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Full text of "Insect, weed & plant disease survey bulletin"

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• . - 



LIBRARY OF THE 

UNIVERSITY OF ILLINOIS 

AT URBANA-CHAMPAIGN 



£322 

In7 




Digitized by the Internet Archive 

in 2011 with funding from 

University of Illinois Urbana-Champaign 



http://www.archive.org/details/insectweedplan196873univ 



This volume is bound without. R 6^ ( |3^/4 ) 

mn(*ltwY n?l(^l) 

which is/are unavailable. 



./- n\. / 




<A-\ '* 



INSECT 

SURVEY 

BULLETIN 






.i 




State 






FOR IMMEDIATE RELEASE 









College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 

U. S. Department of Agriculture Cooperating 

APR - 9 ^368 

March 15, 1968 



INSECT SURVEY BULLETIN NO. 



mm 

i 



This series of weekly bulletins provides a general look at the insect situation 
(fruit insects excepted) along with suggested, abbreviated control measures. Each 
individual should check his own fields to determine local conditions. Before ap- 
plying insecticides 3 read the labels carefully and follow all precautions. This 
will not only insure personal safety, but will also prevent residue hazards. 

Cattle lice have increased steadily in numbers since late last fall and have now 
reached a peak population. Infested cattle rub, lick, and bite themselves ex- 
cessively; as a result, hair loss and even raw or bloody patches on the skin are 
common symptoms of louse infestations. Scaly skin, weather, temperature, and diet 
can also cause similar symptoms. Make a spot check for lice on a few of the ani- 
mals with the roughest appearance; look first along the brisket and neck, then 
check the withers and tail crown for the small dark blue or black sucking- lice or 
reddish-brown chewing lice. Tiny, oval, yellow or black eggs (nits) stuck to hairs 
are also a sign of lice. 

Control cattle lice with sprays. Although using dusts and backrubbers will usually 
control light infestations, they will not control moderate to severe infestations. 

Use Ciodrin for dairy cattle. Mix 1-1/2 pints of liquid concentrate containing 
4 pounds of active ingredient per gallon, 2 pints containing 3.2 pounds, or 3 pints 
containing 2 pounds per gallon with 100 gallons of water. Rotenone is also effec- 
tive. 

For beef cattle, use lindane--l-l/2 pints of 20-percent lindane liquid concentrate 
per 100 gallons of water; or malathion, 3 quarts of the 50- to 57 -percent mala- 
thion liquid concentrate per 100 gallons of water. When using lindane, allow 30 
days to elapse between treatment and slaughter. Lindane and malathion are pre- 
ferred for louse control on beef cattle because both materials will also control 
mange mites as well as lice. 

Follow these suggestions when spraying cattle for lice: 

1. Add 1 to 2 pounds of a washday detergent to each 100 gallons of finished spray 
to aid in wetting and in penetrating the thick coat. 

2. Apply 1-1/2 to 2 gallons of finished spray per animal, if they weigh 800 pounds 
or more. 

3. Thorough coverage of each animal from head to tail is essential for good con- 
trol. Spraying must be thorough; if not, repeat the treatment in 2 weeks. 



-2- 

On warm days throughout the winter, adult alfalfa weevils have been depositing 
eggs in alfalfa stems. A few larvae can be found now. Except in extreme southern 
Illinois or on steep south or west slopes, damage will not be visible for another 
2 or 3 weeks . > 



Damage will be severe in almost all alfalfa fields south of a line from Paris to 
Alton. Moderate to heavy damage will occur in most alfalfa fields north to a line 
from Watseka to Springfield to Hardin. 

Egg laying has just begun, and a recent egg survey in east-southeastern Illinois 
shows that 35 percent of the alfalfa fields already have enough eggs for poten- 
tially severe larval damage. This indicates that a severe alfalfa weevil problem 
can be expected this spring. 

Much attention has been given the brown recluse spider dur- 
ing the past year. It is yellow to dark brown in color , 
about 1/2 inch long, with a distinct fiddle-shaped dark 
marking behind the "head." It was first found in 1959 in 
Carbondale and Harrisburg, as far north as Sullivan by 1965, 
and as far north as Chicago by 1967. (See attached map.) 

This spider is usually found in dark places in the home; 
closets , crawl spaces, and other dark storage spaces are fav- 
orite spots. However, the spider is not aggressive and does 
not attack; it tries to escape when disturbed. When pinched 
(as in clothing, gloves, or bedding), it will bite. Consult 
your doctor about any such bites . 




Note fiddle -shaped 
dark marking behind 
the "head." 



We are trying to catalogue the distribution of this spider and others, and we will 
identify all spiders sent to the Natural History Survey in Urbana. Send specimens 
in alcohol to Dr. John Unzicker, Room 93, Natural Resources Building, Illinois 
Natural History Survey, Urbana, Illinois 61801. Include your name, address, and 
where the spider was found. Dr. Unzicker will reply as quickly as time permits. 

North of Highway Route 36, corn rootworms are a common topic of conversation. 
Several new insecticides for application at planting time are on the market. 
Dasanit was not included in the printed Illinois recommendations of December 31, 
1967, because it did not have federal label approval. Recently, it received this 
approval, and is now recommended for rootworm control in Illinois. We classify 
it in the same category with phorate, BUX ten, and dyfonate. 

Plant pathologist M.P. Britton states that during the past few weeks, there has 
been a rash of questions on brown stem rot of soybeans and the reason for its 
build-up. Under Illinois conditions, a build-up of brown stem rot of soybeans 
occurs when beans are grown for several years successively in the same field. Red 
clover in a rotation has not been shown to be a factor in the spread of brown stem 
rot of soybeans. However, since red clover can be infected by the fungus, we do 
not think that soybeans should follow red clover. The normal practice, of course, 
is to follow red clover with corn. 

CAUTION: REMEMBER— READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS CAREFULLY. 

This weekly report was prepared by H.B. Petty, Steve Moore, Roscoe Randell, and 
Don Kuhlman, Illinois Natural History Survey and University of Illinois College 
of Agriculture, in cooperation with the USDA Agricultural Research Service, Plant 
Pest Control Branch, from information gathered by entomologists and cooperators 
who send in weekly reports from their own localities. 



[ 



A\ 



BROWN RECLUSE SPIDER DISTRIBUTION 



Date in county indicates 
year the spider was first 
found. 




1964 




INSECT 

SURVEY 

BULLETIN 



#«■»% 




'%«*' 



.# 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



State / County / Local Groups / U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



March 23, 1968 



INSECT SURVEY BULLETIN NO. 2 



This series of weekly bulletins provides a general look at the insect situation 
(fruit insects excepted) along with suggested, abbreviated control measures. Each 
individual should check his own fields to determine local conditions. Before ap- 
plying insecticides , read the labels carefully and follow all precautions. This 
will not only insure personal safety, but will also prevent residue hazards. 

This week was National Poison Prevention Week, but attention should be focused on 
the problem for all year long. In agriculture, the next 3 to 4 months are the 
most critical, since the majority of insecticides used on farms will be applied 
during that time. We constantly repeat, "Read and follow the label." 

These are precautions to follow when handling insecticides: 



1. 

2. 
3. 
4. 
5. 
6. 
7. 



if iii* 



Wear gloves 

Avoid breathing dust or spray by wearing an appropriate mask 

Wear goggles ^u..^ ut 

Do not smoke p^ „ c, \<tf$ 

Wash carefully after use 

Wash clothes each day 

If insecticides are spilled on your clothing, change to clean clothes immedi- 
ately 

8. Store insecticides away from livestock feed, and always store insecticides in 
their original containers 

These and many other warnings can and are listed as precautions, but above all 
think first and handle insecticides with care. Carelessness can be fatal. In 
agriculture , the record is good. We have had only one accidental death from a 
pesticide used in commercial agriculture since 1960- -there need be no more. 

Unfortunately, pesticides are not used as carefully by homeowners, and small chil- 
dren are the ones who suffer the most. Be sure to store and place insecticides 
where children cannot get to them. Each year in Illinois, 2 to 4 people die from 
pesticides as a result of carelessness and there are about 750 cases (mostly chil- 
dren) of accidental ingestion of pesticides. 

One way to avoid insecticide accidents in the home is to keep insects out. As an 
example, most ants live outdoors, as do crickets, centipedes, and spiders. They 
crawl up over the foundation and into your home. You can keep them out by apply- 
ing 2-percent chlordane to the foundation and to a 2- to 4-inch band of soil 
around your home in April or May and again in August. This will control these 



insects before they enter your home and eliminate the indoor use of ant baits, which 
small children are tempted to eat. But above all, keep pesticides under lock and 
key where children cannot get them. 

Alfalfa weevil damage will be severe in almost all alfalfa fields south of a line 
from Paris to Alton. Moderate -to -heavy damage will occur in most alfalfa fields 
north to a line from Watseka to Springfield to Hardin. Weevil feeding will be ap- 
parent in alfalfa fields north of this line, but will not reach significant propor- 
tions. 

Larvae are now hatching in southern Illinois; they can be found quite easily. Dam- 
age has not occurred yet; but by next week, feeding should be noticeable. As the 
weather warms, observe fields closely for weevil feeding. The first insecticide 
application will probably not be needed in the more advanced fields in extreme 
southern Illinois until the first week in April or later, depending on the weather. 

If you intend to protect your alfalfa from weevil attack, begin to make prepara- 
tions now. Apply the insecticide when weevil feeding has become noticeably appar- 
ent on 25 percent or more of the terminals; a second application may be needed 
about 2 weeks later as more larvae hatch; and a third one may be needed to protect 
the new shoots after the first cutting has been removed. This may seem expensive, 
but you will produce more and better-quality alfalfa than in the past. 

The recommendations are : 

1. Experienced commercial applicators who have the proper protective clothing 
will get best results with methyl parathion applied at 1/2 pound per acre or 
a special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per 
acre. Azinphosmethyl can be applied only once per cutting. 

2 . The person not properly equipped with protective clothing to use methyl para - 
thion or azinphosmethyl can use a mixture of 5/4 pound of malathion and 5/4 
pound of methoxychlor per acre or a mixture of 1/2 pound of diazinon and 1 
pound of methoxychlor per acre. When air temperatures are above 60° F., you 
may also use 1 1/4 pounds of malathion per acre. 

Allow 15 days to elapse between an application of methyl parathion and harvest, 
16 days for azinphosmethyl, 7 days with methoxychlor, and 7 days with diazinon. 
No interval is required between the application of malathion and harvest. 

We are continually questioned about the most effective material. Methyl para- 
thion, put on by commercial applicators who wear protective clothing, usually pro- 
vides the best control under all conditions. Furthermore, the total cost of chem- 
ical and application may not be any greater than chemical cost plus labor for the 
materials used by the individual applicator. Regardless of what or how the mate- 
rial is applied, timing is critical. An application made too early may be wasted, 
but an application that is too late usually means a crop loss. Apply when 25 per- 
cent of the terminal growth has obvious feeding damage. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The 
exception is on stubble, where 10 gallons per acre by ground will be sufficient. 



A dormant oil application in the early spring will assist in controlling certain 
scale insects and overwintering red mite eggs. Purchase dormant oil and mix with 
water according to directions on the label. A 2 -percent oil spray is sufficient 
to control San Jose, Putman, and tulip tree scale. Do not apply when temperatures 
are below 40° F. or if new growth is present. 

CAUTION: REMEMBER— READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS CAREFULLY. 

This weekly report was prepared by H.B. Petty, Steve Moore, Rosooe Randell, Don 
Kuhlman, and Stephen Sturgeon, Illinois Natural History Survey and University of 
Illinois College of Agriculture , in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch, from information gathered by entomologists and 
cooperators who send in weekly reports from their own localities. 




>tate / County / Local Groups 



INSECT 

SURVEY 

BULLETIN 



*« Tf #% 




%>TY9& 



^ 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



March 29, 1968 



INSECT SURVEY BULLETIN NO. 5 



This series of weekly bulletins provides a general look at the insect situation 
(fruit insects excepted) along with suggested, abbreviated control measures. Each 
individual should check his own fields to determine local conditions. Before ap- 
plying insecticides, read the labels carefully and follow all precautions. This 
will not only insure personal safety, but will also prevent residue hazards. 

Alfalfa weevil larvae are now hatching in southern Illinois. The coming of warmer 
weather has increased egg hatch and egg laying, resulting in a buildup in the num- 
ber of larvae; also, the alfalfa is beginning to grow. Check the alfalfa fields 
closely for damage caused by the larvae feeding on the terminal leaves . 

In the new plant growth, newly-hatched larvae feed within the growing plant tips 
and on the upper leaves as they open. They skeletonize the leaves, which then 
dry rapidly. Severely damaged fields take on a grayish to whitish cast. 

If you intend to protect your alfalfa from weevil attack, begin to make prepara- 
tions now. The first insecticide applications will probably not be needed in more 
advanced fields in extreme southern Illinois until the first week in April or later, 
depending on the weather. A spot check of alfalfa tips will give you some indica- 
tion of damage. Select 25 terminal tips at random, and carefully examine them for 
the presence of small larvae or feeding injury. 

Apply the insecticide when weevil feeding has become noticeably apparent on 25 
percent or more of the terminals. Newly-hatched larvae are about 1/20 of an inch 
long and are yellow, except for a shiny black head. When full grown, they are 
about 5/8 of an inch long, green, with a wide white stripe running down the middle 
of the back. 

The recommendations are: 

1. Experienced commercial applicators who have the proper protective clothing 
will get best results with methyl parathion applied at 1/2 pound per acre or 
a special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per 
acre. Azinphosmethyl can be applied only once per cutting. 

2. The person not properly equipped with protective clothing to use methyl para - 
thion or azinphosmethyl can use a mixture of 5/4 pound of malathion and 5/4 
pound of methoxychlor per acre or a mixture of 1/2 pound of diazinon and 1 
pound of methoxychlor per acre. When air temperatures are above 60° F. , you 
may also use 1 1/4 pounds of malathion per acre. 

bltliVEUSITY OF ILLINOIS 

APR -9 1968 
LIBRARY 



Allow 15 days to elapse between an application of methyl parathion and harvest, 
16 days for azinphosmethyl, 7 days with methoxychlor , and 7 days with diazinon. 
No interval is required between the application of malathion and harvest. 

We are continually questioned about the most effective material. Methyl para- 
thion, put on by commercial applicators who wear protective clothing, usually 
provides the best control under all conditions. Furthermore, the total cost of 
chemical and application may not be any greater than chemical cost plus labor 
for the materials used by the individual applicator. Regardless of what material 
is applied or how, timing is critical. An application made too early may be 
wasted, but an application that is too late usually means a crop loss. Apply 
when 25 percent of the terminal growth shows feeding damage. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The 
exception is on stubble, where 10 gallons per acre by ground will be sufficient. 

White grubs will probably be present in some fields this spring, especially in 
the east-central part of the state where they were a problem in 1965 (when ap- 
proximately 20 thousand acres of soybeans were damaged) . These U-shaped larvae 
with a brown head have been overwintering down in the soil, after hatching from 
eggs this past fall, and are now near the surface. One species of white grub or 
June beetles commonly lays its eggs in soybean fields. True white grubs usually 
complete their life cycle in 3 years, spending almost 2 years in the soil as grubs. 
This insect feeds on the roots of both corn and soybeans. One indication that this 
pest is present in a field is that they will be turned up to the surface during 
plowing. If many birds are feeding on freshly plowed or disced ground, check to 
see if there are white grubs present. If the field is to be planted to corn, 
broadcast 3 pounds of actual aldrin or heptachlor per acre and incorporate it 
into the soil. Do not use these chemicals on fields to be planted in soybeans. 
Ahead of soybeans, broadcast 4 pounds of actual diazinon per acre and incorporate 
it into the soil. 

White grubs and other soil infesting insects in the home garden can be controlled 
with a broadcast application of diazinon. Apply 1 ounce of actual diazinon per 
1,000 square feet of garden area and work it into the soil. Do not apply aldrin 
or heptachlor to home garden soil . 

Spring cankerworms will be hatching soon and will be feeding on many deciduous 
trees, such as American elms and apple. These brown to dark-green to black mea- 
suring worms (sometimes called inch-worms) can completely defoliate trees in the 
early spring as the trees leaf out. For best control results, apply the chemical 
when the worms are still small. Use either carbaryl (Sevin) with 2 pounds of 50- 
percent wettable powder in 100 gallons of water or lead arsenate with 4 pounds 
per 100 gallons of water. 

Clover mites are annoying in some homes. These mites are tiny, orange-to-black 
moving specks about the size of the period at the end of this sentence. They 
cover furniture, walls, curtains, window sills, etc., as they attempt to find 
their way outdoors. Pick them up with a vacuum cleaner or use an 0.1-percent 
pyrethrin spray from a pressurized spray can for quick knockdown. Before fall, 
remove grass, clover, and weeds next to the foundation- -leaving a strip of soil 



-3- 

at least 18 inches wide. This bare soil serves as a barrier to the mites. Re- 
planting this strip to such flowers as zinnia, marigold, chrysanthemum, or salvia 
(which do not attract clover mites), will prevent clover mite problems next year. 

Cluster flies (attic flies) are a nuisance in some homes. The adult flies entered 
houses and buildings last fall to get shelter for the winter. Since attics and 
basements are not as carefully sealed as other areas, large numbers of flies can 
gather there. With the onset of warm, sunny days, they become active and leave 
the partitions and voids to congregate at windows. Clusters sometimes include 
thousands of flies. Though they are a nuisance, cluster flies don't injure 
either persons or materials. They are slightly larger and more sluggish than 
house flies. 

The best indoor control is 20-percent dichlorvos (DDVP) resin strips placed in 
attics, basements, and other fly- infested rooms. One strip per 1,000 cubic feet 
(one strip per average room) is effective about 4 to 6 weeks. Do not use in 
rooms where tropical fish are present or in pet shops . 

CAUTION: REMEMBER- -READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 
CAREFULLY. 

This weekly re-port was prepared by H.B. Petty, Steve Moore, Rosaoe Randell, Don 
Ruhlman, and Stephen Sturgeon, Illinois Natural History Survey and University of 
Illinois College of Agriculture , in cooperation with the USDA Agricultural Re- 
search Service, Plant Pest Control Branch, from information gathered by entomolo- 
gists and cooperators who send in weekly reports from their own localities. 




tate 



INSECT 

SURVEY 

BULLETIN 



^« T %//> 







College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



S. Department of Agriculture Cooperating 



/\PR -9 1968 April 5, 1968 
INSECT SURVEY BULLETIN NO. 4 



FOR IMMEDIATE RELEASE 



This series of weekly bulletins provides a general look at the insect situation 
(fruit insects excepted) along with suggested, abbreviated control measures. Each 
individual should check his own fields to determine local conditions. Before ap- 
plying insecticides , read the labels carefully and follow all precautions. This 
will not only insure personal safety, but will also prevent residue hazards. 

Alfalfa weevils continue a slow buildup in southern Illinois. Egg hatch and larval 
feeding have been reduced by the cool weather. Thus, the expected damage has not 
yet occurred. However, some fields south of Route 13 have terminal feeding damage 
of about 10 percent, but treatment should be delayed in these fields until 25 per- 
cent or more of the terminals are damaged. Depending on the weather, the first 
insecticide applications may be necessary south of Route 13 in the second week of 
April, and 10 days to 2 weeks later north of this line. [In cool weather (below 
40° F.), larvae do little or no feeding.] 

It is most important to inspect alfalfa fields frequently. Spraying too early or 
too late can be a waste of time and money. A spot check of alfalfa tips will give 
you some indication of damage. Select 25 terminal tips at random in several loca- 
tions of the field, and carefully examine them for the presence of small larvae or 
feeding injury. Apply the insecticide when larval feeding has become apparent on 
25 percent or more of the terminals. Newly-hatched larvae are about 1/20 of an 
inch long and are yellow, except for a shiny black head. When full grown, they 
are about 3/8 of an inch long, green, with a wide white stripe down the middle of 
the back. 

The recommendations are: 

1. Experienced commercial applicators who have the proper protective clothing will 
get best results with methyl parathion applied at 1/2 pound per acre or a spe- 
cial alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per acre. 
Azinphosmethyl can be applied only once per cutting. 

2. The person not properly equipped with protective clothing to use methyl para - 
thion or azinphosmethyl can use a mixture of 3/4 pound of malathion and 5/4 
pound of methoxychlor per acre, or a mixture of 1/2 pound of diazinon and 

1 pound of methoxychlor per acre (3 quarts of the commercially prepared mix- 
ture, Alfatox) . When air temperatures are above 60° F., you may also use 
1 1/4 pounds of malathion per acre. 



Allow 15 days to elapse between the application of methyl parathion and harvest; 
16 days for azinphosmethyl ; and 7 days with methoxychlor, diazinon, or mixtures of 
them. No interval is required between the application of malathion and harvest. 

We are continually questioned about the most effective material. Methyl parathion, 
put on by commercial applicators who wear protective clothing, usually provides the 
best control under all conditions. Furthermore, the total cost of chemical and 
application may not be any greater than the chemical cost plus labor for the mate- 
rials used by the individual applicator. Regardless of what material is applied 
or how, timing is critical. An application made too early may be wasted, but an 
application that is too late usually means a crop loss. Apply when 25 percent of 
the terminal growth shows feeding damage. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The ex- 
ception is on stubble, where 10 gallons per acre by ground will be sufficient. 

Clover leaf weevils can be confused with alfalfa weevils. This large, pale-green 
worm with white stripes down its back has a tan or brown head; the alfalfa weevil 
has a black head. There have been reports of this insect in clover and alfalfa 
fields in the western part of the state. They feed mainly at night, and hide 
around the base of the plant during the day. Most stands of alfalfa and clover 
outgrow the damage from this insect; also, parasites and a fungus disease usually 
prevent a buildup of this pest. However, if feeding is severe and growth is slow, 
a spray of 1 pound of malathion will be effective. Pea aphids, if present, will 
also be controlled by the malathion. 

Fungus gnats are numerous in some wheat fields. These small gnat- like flies (some- 
times mistaken as Hessian fly), which develop in wet, decaying organic matter, are 
not pests of the wheat plants. But they do manage to crawl through window screens 
and become a nuisance in homes. Inside the home, a 0.1-percent pyrethrin space 
spray applied from a pressurized can will give quick knockdown and relief. 

Clover mites are annoying in some homes. These mites are tiny, orange- to-black 
moving specks about the size of the period at the end of this sentence. They cover 
furniture, walls, curtains, window sills, etc., as they attempt to find their way 
outdoors. Pick them up with a vacuum cleaner or use an 0.1-percent pyrethrin spray 
from a pressurized spray can for quick knockdown. Before fall, remove grass, clover, 
and weeds next to the foundation- -leaving a strip of soil at least 18 inches wide. 
This bare soil serves as a barrier to the mites. Replanting this strip with flowers 
such as zinnia, marigold, chrysanthemum, or salvia (which do not attract clover mites) 
will prevent clover mite problems next year. 

Winged termites and ants are appearing and are causing concern to homeowners. If 

warms of flying termites appear, check for mud tubes on inside basement walls and 
on the outside of foundations. Many termite control problems are extremely com- 
plicated and require an experienced exterminator. 



TERMITE or ANT? the differences are: 

ANTENNA ELBOWED 



TERMITE 




WINGS(IFPRESENT) 
MANY SMALL VEINS 
BOTH WINGS 

SAME SIZE 



ANTENNA 
NOT ELBOWED 



^CHEMISE" 
V. WAIST 

"HOUR- 
GLASS" 
WAIST 




WINGS 
"(IF PRESENT) 

FEW VEINS 
HIND WINGS SMALLER THAN 
FRONT WINGS 



NOT FOR PUBLICATION: SPECIAL NOTE TO RADIO AND TELEVISION STATIONS 

You can have University of Illinois entomologists on your station each week telling 
farmers how to best control their insect pests. All you do is telephone (217) 333- 
2614 each Friday. An automatic answering device will play a 1:40 tape summarizing 
the week's insect activity and forecasting the next week's problems. This summary 
gives only highlights. We hope you will continue to use these in-depth written 
reports. Contact your Extension adviser in agriculture for the local angle. 



Have your recorder running when you call . The recorded information is different 
for the northern and southern portions of the state. Therefore, if you are in the 
northern half of Illinois , call between 9 a.m. and 11 a.m. each Friday; if you are 
in the southern half of the state , call between 11:05 a.m. and 1 p.m. each Friday. 

For more information or in case of difficulty, call Mr. Cliff Scherer in the Agri- 
cultural Communications Office, 330 Mumford Hall, University of Illinois, Urbana. 
Phone (217) 333-4783. 

CAUTION: REMEMBER- -READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared by E.B. Petty, Steve Moore, Roscoe Randell, Don 
Kuhlman, and Stephen Sturgeon, Illinois Natural History Survey and University of 
Illinois College of Agriculture, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch, from information gathered by entomologists and 
cooperators who send in weekly reports from their own localities . 



J./*.'! 




State / County 



Local Groups 



INSECT 

SURVEY 

BULLETIN 



^«T%/ 




% 



M 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 

U. S. Department of Agriculture Cooperatinq 

THE UBRARV fir fflf 



FOR IMMEDIATE RELEASE 



*> 



I IS 



UNIVERSITY Of ILUNUK 

INSECT SURVEY BULLETIN NO. 5 



April 12, 1968 



This series of weekly bulletins provides a general look at the insect situation 
(fruit insects excepted) along with suggested, abbreviated control measures. Each 
individual should check his own fields to determine local conditions. Before ap- 
plying insecticides, read the labels carefully and follow all precautions. This 
will not only insure personal safety, but will also prevent residue hazards. 

The alfalfa weevil is damaging alfalfa south of Highway 13. A few fields have 
already been sprayed. Feeding is more evident than usual on the lower leaves 
possibly because of the cool weather of recent weeks. Infestations and damage 
vary from field to field and each field should be judged on an individual basis. 
At least two and possibly three treatments will be needed to protect alfalfa 
stands in this area. 



In the area between Highways 13 and 40, larvae are present and feeding i 
able. Some fields in this area will probably need treatment by the end 
week (April 19 or 20) . Peak spraying in this area should occur the week^of 
April 21. 



notice- 

my gf 



H '* 30 



m 



B'vrl'-ai 



J ^u 



In the area between Highway 40 and a line from Watseka to Hardin, weev f rK-ac£)iwi'ty, 
is just beginning, and it will be at least another 2 weeks before the situation"" 
becomes critical. 



Apply the insecticide when larval feeding has become apparent on 25 percent or 
more of the terminals. Serious injury can occur within a few days after this 
feeding level is reached. 

The recommendations are: 



Experienced commercial applicators who have the proper protective clothing 
will get best results with methyl parathion applied at 1/2 pound per acre or 
a special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per 
acre. Azinphosmethyl can be applied only once per cutting . Do not harvest 
for 15 days after treatment with methyl parathion and for 16 days with azin- 
phosmethyl . 

The person not properly equipped with protective clothing to use methyl para - 
thion or azinphosmethyl can use a mixture of 3/4 pound of malathion and 3/4 
pound of methoxychlor per acre (3 pints of a concentrate containing 2 pounds 
of methoxychlor and 2 pounds of malathion per gallon) or a mixture containing 



-2- 

at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre (2 1/2 to 
5 quarts of the commercially prepared mixture Alfatox) . You may also use 
1 1/4 pounds of malathion per acre (1 quart of the 5-pounds-per-gallon con- 
centrate) in the morning on days when air temperatures will be above 60° F. 
Do not harvest for 7 days after treatment with methoxychlor, diazinon, or 
mixtures of them. There is no waiting period for malathion. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The 
exception is on stubble, where 10 gallons per acre by ground will be sufficient. 

A few clover leaf weevils can be found in every alfalfa and clover field but as 
yet no damaging populations have been reported. 

White grubs are moving up from the subsoil to feed on grass and weed roots and 
later on the roots of corn and soybeans. The common three-year-cycle grub caused 
problems in corn and soybeans in the central sections in 1965 and is expected to 
be a problem in some fields this year. The grubs are about half grown in this 
second year of their development and will feed throughout the growing season. 
Watch for grubs when plowing or during other tillage operations, and if many are 
present or if the field has a history of grub problems, plan to apply control 
measures. If the field is to be planted to corn, apply 1 1/2 pounds of actual 
aldrin or heptachlor and disk it in ahead of planting. Do not use either aldrin 
or heptachlor on fields to be planted to soybeans. Ahead of soybeans, 4 pounds 
of actual diazinon broadcast and disked in should provide get-by protection. 

English grain aphids are present in wheat fields but are not numerous enough to 
be of concern. Predators, parasites, and diseases usually hold grain aphid num- 
bers in check. We have observed some fields of wheat in poor condition, but dis- 
ease (see report below), not aphids, was the cause. Aphids are of greatest con- 
cern when the populations are high at the time wheat is heading out. No control 
is needed at this time. 

Septoria leaf blotch is abundant in most wheat fields in Illinois. Extremely 
favorable conditions for infection of young wheat plants occurred last fall. 
Defoliation and invasion of crowns at that time produced weakened plants. Some 
of these did not survive the winter. Spores are produced on the dead leaves in 
pycnidia, and the disease can be expected to spread upward onto the new leaves 
as long as cool, wet weather persists. 

The pycnidia appear as small black dots , and the resulting speckled appearance 
of the dead tissue is a reliable symptom for identifying the disease. New infec- 
tions appear as yellow to light-green areas. At first they are confined to tis- 
sue between the leaf veins, but later spread to form irregular blotches. 

Septoria leaf blotch does its greatest damage to seedlings in the fall and to 
tillers in the early spring. In some years the disease kills most of the rosette 
leaves and up to 50 percent of the tillers. If most of the leaves of maturing 
plants are killed before the grain reaches the soft dough stage, the grain is 
lightweight and shriveled. 



There is some winter injury in winter wheat. 
Much of the damage is from heaving. Some is 
from cold-weather injury to plants weakened by 
disease or flooding. (Plant disease reports are 
prepared by M.P. Britton, Extension Plant Pathol- 
ogist.) 

Bagworm eggs are present in the old sacs on many 
evergreens and other shrubs in the home yard. 
These eggs will hatch about June 1 in central 
sections. If you hand-pick and destroy these 
bags now, you may not have to spray your ever- 
greens in June. 

Lawn grubs can destroy the best -kept lawn. Dam- 
aged turf turns brown in spots , and the sod can 
be rolled up like a carpet, often exposing the 
grubs beneath. If grubs were a problem in your 
lawn last summer or if you wish to prevent the 
problem, apply 1 1/4 pounds of actual chlordane 
per 10,000 square feet. In established sod, ap- 
ply as granules or as a spray. When spraying, 
treat only a small area and then water in thoroughly 

before spraying another small area. For new seedings, mix the chlordane in the soil 

before planting. Do not plant vegetable root crops in treated soil for 5 years. 

This treatment should also eliminate ants and soil-nesting wasps from the yard. 

It will not prevent problems with sod webworms. 

Treat now for pine tip moths which infest the tips of mugho, scotch, and red pine. 
Apply a DDT spray to the ends of the branches and repeat the treatment again in 
late June. To mix, use 3 tablespoons of the 25-percent liquid concentrate per gal- 
lon of water. 

CAUTION: REMEMBER- -READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS. 




This weekly report was prepared by H.B. Petty, Steve Moore, Rosooe Randell, Don 
Kuhlman, and Stephen Sturgeon, Illinois Natural History Survey and University of 
Illinois College of Agriculture , in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch, from information gathered by entomologists and 
cooperators who send in weekly reports from their own localities . 




INSECT 

SURVEY 

BULLETIN 



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College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



April 19, 1968 



INSECT SURVEY BULLETIN NO. 6 



This series of weekly bulletins provides a general look at the pest situation 
(fruit insects excepted) , along with suggested, abbreviated control measures. 
Each individual should check his own fields to determine local conditions. This 
release also contains a plant disease report supplied by the Department of Plant 
Pathology and the Illinois Natural History Survey, as well as a weed control re- 
port supplied by the Departments of Agronomy and Horticulture^ 



FIELD CROP PEST PROBLEMS 



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Alfalfa weevil development is now progressing rapidly. 

weevil situation this spring is quite different than it was last year. In the 
winter of 1966-1967, weevil adults were depositing eggs and larvae were hatching 
all winter long. As a consequence, weevil larvae were feeding on the alfalfa 
plants even before they were growing. This past winter, although weevil adults 
deposited a few eggs, they did not really begin to lay eggs until the beginning 
of alfalfa growth. By the time the eggs began to hatch, alfalfa had been growing 
for 2 weeks or longer. Either one of two things could happen because of this 
late start: 

1. Egg laying, hatch, and damage may be condensed into a shorter period, with 
feeding and damage severe for a short period, then declining rapidly. Egg 
counts indicate that this may already be taking place. 

2. Egg laying may be prolonged over the same span of time as last year. In this 
case, noticeable damage will occur late into the second growth. 

General statements are difficult to make because of the retarded development of 
the alfalfa weevil. Therefore, each field must be judged individually. Ordinar- 
ily, 3 applications of an insecticide are needed to control moderate to heavy 
infestations. Make the first application when 25 percent of the terminals (in- 
dividual stems, not plants) show feeding. A second application is required about 
2 weeks later, since more hatch occurs and weevils migrate into the fields. A 
third application is made to protect the new shoots of the second growth, after 
the first cutting has been removed. 

This year, some of the early developing alfalfa may not require 2 insecticide 
applications on the first crop. However, apply an insecticide when 25 percent 
or more of the terminals show feeding. Examine the field 10 days to 2 weeks later. 
If weevil feeding is increasing rapidly and the crop is still 10 days or even 



longer from harvest, you may want to make another insecticide application. Al- 
though, if the crop is within a week or so of harvest, you may prefer to cut the 
hay a few days early to avoid the extra cost of insecticide. In this case, be 
prepared to spray the stubble as soon as you remove the hay, since those larvae 
present will move immediately from the hay to the new shoots in large numbers and 
damage could be severe. Later developing fields will probably require the normal 
insecticide program. 

In the area south of a line from Harrisburg to Carbondale, spraying began 10 days 
ago, and fields should be examined to see if a second application is needed during 
the next 10 days. Advanced fields may be harvested a little early to avoid the 
second application, but be ready to spray the stubble. 

Spraying began this week in the area north of this Harrisburg-Carbondale line, 
up to a line from Carmi to Pinckneyville to Sparta. Weevil feeding in that area 
became quite apparent this week, and untreated fields will be severely damaged 
within another 7 days . 

Hatching began late this week in the area north of the Carmi-Sparta line and south 
of Route 50. Hatch will progress rapidly now. Examine fields to find out when 
25 percent of the terminals show feeding. Many fields will meet this criterion 
by Monday, April 22. 

Fields in the area north of Route 50 and south of Route 40 should begin to show 
feeding this week. Some may require an insecticide application. 

Larvae will be appearing in fields in the area north of Route 40 and south of a 
line from Watseka to Springfield to Hardin late in the week of April 22 or early 
in the week of April 29. 

The insecticide recommendations are: 

1. Experienced commercial applicators who have the proper protective clothing 
will get the best results with methyl parathion applied at 1/2 pound per acre 
or a special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound 
per acre. Azinphosmethyl can be applied only once per cutting . Do not har- 
vest for 15 days after treatment with methyl parathion and for 16 days with 
azinphosmethyl . 

2. The person not properly equipped with protective clothing to use methyl 
parathion or azinphosmethyl can use a mixture of 3/4 pound of malathion and 
5/4 pound of methoxychlor per acre (3 pints of a concentrate containing 2 
pounds of methoxychlor and 2 pounds of malathion per gallon) or a mixture con- 
taining at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre 
(2-1/2 to 3 quarts of the commercially prepared mixture Alfatox) . You may 
also use 1-1/4 pounds of malathion per acre (1 quart of the 5-pounds-per- 
gallon concentrate) in the morning, on days when air temperatures will be 
above 60° F. Do not harvest for 7 days after treatment with methoxychlor, 
diazinon, or mixtures of them. There is no waiting period for malathion. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The 
exception is on stubble, where 10 gallons per acre by ground will be sufficient. 



A few clover leaf weevils can be found in every alfalfa and clover field but as 
yet no damaging populations have been reported. 

Cutworms can also be found feeding on red clover in south-central and southern 
Illinois. The clover, however, seems to be growing away from the damage. 

White grubs have been discussed in the past 2 weeks as a potential soybean and 
corn root pest in the eastern and central areas of Illinois. They have a 3-year 
life cycle. The last outbreak was in 1965, when many fields of soybeans were 
severely damaged. If you find lots of grubs as you are plowing, you may want to 
apply a soil insecticide. If the field is to be planted in corn, apply 1-1/2 
pounds of actual aldrin or heptachlor and disk it in ahead of planting. Do not 
use either aldrin or heptachlor on fields to be planted in soybeans. Ahead of 
soybeans, 4 pounds of actual diazinon- -broadcast and disked- in- -should provide 
get-by protection. 

We will appreciate reports of this pest this year. Please notify your county 
Extension adviser. 

Plant Diseases 

Septoria leaf spot is now spreading upwards on the leaves of wheat, and will con- 
tinue to spread as long as the cool weather persists. 

Powdery mildew was observed on wheat south of Highway 40 this past week. This 
disease will become more prevalent as the weather warms up. It is readily rec- 
ognized by the powdery white growth that occurs in patches on leaves and sheaths. 

Weeds 

Ramrod has additional clearance in 1968 for corn- -including seed production fields, 
sweet corn, and corn for grain forage or silage. Livestock can now be turned into 
Ramrod -treated cornfields after harvest. You may also use Ramrod on sorghum, 
unless the sorghum is to be grazed by dairy cattle or used as silage for dairy 
cattle. 

Ramrod is not cleared for weed control on soybean fields, if the beans are to be 
used for food, feed, or oil. It can be used if the soybeans are to be used for 
seed only. 

Sutan is now cleared for field corn, sweet corn, and corn used for silage. It is 
not cleared for hybrid corn grown for seed. (Several seed corn companies will 
have trials to further check corn tolerance this year.) It may be used alone at 
4 pounds actual (2/3 gal.) per acre on a broadcast basis. Incorporate into the 
soil immediately after application. 

One of the major ideas of interest is to apply a combination of Sutan and Atrazine. 
Although results with this combination looked promising in 1967, only field-trial 
use is suggested in 1968, in order to obtain more information on weed control and 
crop tolerance under a wider range of conditions. In trying this combination, we 
suggest 3 pounds (1/2 gal.) of Sutan with the Atrazine; 1-1/4 pounds of Atrazine 
SOW on lighter-colored soils may be sufficient, but nearly 2 pounds may be needed 
on the darker soils. Supplies should be sufficient for this purpose in 1968. We 
will also further evaluate the combination this year in research trials. 



-4- 

Paraquat has been cleared for application to emerged weeds prior to corn planting 
or prior to corn emergence. Considerable research has been done with Paraquat 
for killing sod and planting corn in dead sod. Paraquat is a "quick burner" that 
becomes inactivated on contact with the soil. 

Atrazine is usually applied at the same time for residual control. This program 
will likely have very limited acceptance in 1968, but there has been a spurt of 
interest with the new clearance for Paraquat and the development and availability 
of equipment for "no-till" planting. 

Clearance for amitrole and amitrole-T is apparently under review, but no changes 
are anticipated that will affect normal use in Illinois during 1968. 

There have been many questions about seeding -down areas for the government pro- 
gram in 1968, where Atrazine was used on corn in 1967. Plan ahead and do not use 
Atrazine where you plan to seed small grain or small seeded legumes this fall or 
next spring. Soybeans can usually follow Atrazine -treated corn the next year, 
if Atrazine was applied uniformly and accurately at the proper rate. 

HOMEOWNER PEST PROBLEMS 

Insects 

Oystershell scale cannot be controlled now. Many people are asking about con- 
trolling this pest that attacks lilacs, many trees, and other shrubs. It is too 
late to apply a dormant oil and too early for a malathion spray. The eggs are 
under the overwintering scales. These eggs will hatch in late May in southern 
Illinois, early June in central Illinois, and mid-June in northern Illinois. The 
young scales crawl out from under the old scales and migrate to the new growth 
to feed. At this time, they are called crawlers, and they can be controlled with 
malathion sprays. Another application may be required in August. 

Brown recluse spiders are still being discussed. We need one spider from 
each county in our collection for reference purposes. We will appreciate receiv- 
ing specimens. Place suspicious -looking spiders in a small bottle of alcohol and 
send them to Dr. John D. Unzicker, Illinois Natural Historv Survey, Urbana, 
Illinois 61801, for determination. 

Plant Diseases 

Fusarium rot is a problem if you grow gladioli. Start your control program be- 
fore you set the bulbs. First, examine the bulbs before planting and discard any 
that show signs of rot. Then, treat the good bulbs with Arasan dust. Place the 
bulbs in a paper bag with the dust and shake. They are then ready to plant. 

Weeds 

Dandelions and other broadleaved weeds are now prevalent in many lawns ; people 
are asking about control. It is still not too late to apply 2,4-D amine or low- 
volatile esters at the rates suggested on the label. 

Mixtures of 2,4-D with NCPP, dicamba, and others are widely available, and 
these may be used instead of 2,4-D alone. They provide a wider range of weed 
control. Always follow the label when using these herbicides. 



Applications should still kill the dandelions and may prevent formation of the 
seeds. Apply these materials when there is no wind blowing; even light drift of 
spray onto susceptible shrubs, flowers, and vegetables may seriously damage such 
plants. 

Precautions in Using Pesticides 

Each year we get a few reports of spray solution with pesticides siphoning down 
into wells from sprayer tanks. Watch the hose when filling, or attach it to the 
top of the tank so it will remain above the water level. Remove the hose as soon 
as the tank is filled. The proper use of valves on the water system car- also help 
prevent the possibility of such siphoning. Prevention is a lot easier than ef- 
fecting a cure. 

Keeping good records of pesticide applications is like keeping a good record of 
your checking account. It provides a valuable review and helps in making future 
plans. 

Always keep pesticides out of the reach of children and people not accountable 
for their actions. These are the ones who most often suffer from improper pesti- 
cide storage. 

READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS. 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Knhlman, and Stephen 
Sturgeon, Illinois Natural History Survey and University of Illinois College 
of Agriculture. 

Plant Diseases: M.P. Britton, Department of Plant Pathology, and J.L. 
Forsberg, Illinois Natural History Survey. 

Weeds: Ellery Knake, Department of Agronomy, and J.D. Butler, Department of 
Horticulture . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricul- 
tural Research Service, Plant Pest Control Branch. 



£-/V / 




INSECT 

SURVEY 

BULLETIN 



ABWfe, 




ate / County / Local Groups 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbanar l)tocus 

U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



April 26, 1968 



INSECT SURVEY BULLETIN NO. 7 



This series of weekly bulletins provides a general look at the pest situation 
(fruit and commercial vegetables excepted) } along with suggested, abbreviated con- 
trol measures . Each individual should check his own fields to determine local 
conditions . The plant disease report was prepared by the Department of Plant 
Pathology , the insect situation report by the Department of Agricultural Entomol- 
ogy and the Illinois Natural History Survey. 

FIELD CROP PEST PROBLEMS 



Forage Crops 

Alfalfa weevil development almost came to a standstill during this past week. Egg- 
laying by the adults has been slowed down by the cool weather, and feeding has been 
greatly reduced. Larval populations could have exploded this week in much of the 
alfalfa weevil area; actually, there was a noticeable increase of larvae in some 
areas, but not in the proportions expected. 

Adults are quite numerous in alfalfa fields now. When brought inside, these adults 
immediately begin to deposit eggs in quantities. Thus, as soon as the weather 
warms up, we can expect a surge of egg-laying, which will be followed within 10 days 
by severe weevil feeding. 

This delay of weevil development could prove to be beneficial. Many eggs may be 
removed from fields as the hay is harvested; also, many small worms will be either 
removed or killed by exposure to the sun. On the other hand, if the alfalfa is 
cut before or during this siege of egg- laying, eggs will be deposited on the second 
growth, resulting in severe damage to that growth. 

However, the entire situation is so erratic that no general rules that would apply 
to all fields can be given. Each field has to be judged by itself. Take into 
account the abundance of weevil larvae, terminal feeding, alfalfa growth, and 
length of time until harvest. Some fields may escape injury, while others may 
be severely damaged; the temperature of the next few weeks will be the determining 
factor. But in many fields, the alfalfa is now ahead of the weevil, and may con- 
tinue to outgrow the feeding of these insects. 

In the area south of a line from Harrisburg to Carbondale, fields already sprayed 
may be ready for a second treatment by the week of April 29. Some fields that 
have not been treated are showing noticeable damage, which will increase. Fields 



that are 10 days or more from harvest may benefit by an immediate insecticide 
application. Otherwise, cut early. Weevil adults are still laying eggs, eggs 
are hatching, and some larvae are already mature. These pests will still be 
around for another 4 weeks, so \vatch for feeding damage to new shoots on second- 
growth alfalfa and be ready to protect it. 

In the area north of the line from Harrisburg to Carbondale and south of a line 
from Nashville to Mt. Vernon, treatments have already been applied to many fields, 
or soon should be. Some of the earlier-developing fields may not need another 
spray, but second growth will require protection. Although few treatments have 
been made northward to Highway 50, larvae can readily be found in alfalfa fields, 
and their number will increase rapidly with warm weather. The first growth in 
most fields will need at least one spray application, but some of the earlier- 
developing fields on the west side of the state (where the infestation is lighter) 
may escape treatment if cut a bit early. 

In the area north of Route 50 and almost up to Route 40, weevil development is 
very much behind what was expected, and it now appears that treatments will not 
be needed at least until after May l--even later in the area north of Route 40 
and south of the line from Watseka to Springfield to Hardin. 

Apply insecticide controls when 25 percent of the terminals show feeding. The 
insecticide recommendations are: 

1. Experienced commercial applicators who have the proper protective clothing 
will get the best results with methyl parathion applied at 1/2 pound per acre 
or a special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per 
acre. Azinphosmethyl can be applied only once per cutting . Do not harvest for 
15 days after treatment with methyl parathion, 16 days for azinphosmethyl. 

2. The person not properly equipped with protective clothing to use methyl para - 
thion or azinphosmethyl can use a mixture of 3/4 pound of malathion and 3/4 
pound of methoxychlor per acre (3 pints of a concentrate containing 2 pounds 
of methoxychlor and 2 pounds of malathion per gallon) or a mixture containing 
at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre (2-1/2 to 3 
quarts of the commercially prepared mixture Alf atox) . You may also use 1-1/4 
pounds of malathion per acre (1 quart of the 5-pounds-per-gallon concentrate) 
in the morning, on days when air temperatures will be above 60° F. Do not 
harvest for 7 days after treatment with methoxychlor, diazinon, or mixtures 

of them. There is no waiting period for malathion. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The 
exception is on stubble, where 10 gallons per acre by ground will be sufficient. 

Clover leaf weevil populations in red clover fields are now declining. As usual, 
a disease has begun to kill many of them. This disease has appeared in epidemic 
proportions in some fields. 

Pea aphids are conspicuous by their low numbers in alfalfa fields. Ordinarily, 
they are numerous by this stage of growth. Development will depend now on the 
weather and on natural enemies, such as lady beetles and aphid diseases. V\hen 
populations of pea aphids are extremely low on alfalfa in the spring, there is a 
theory that the natural enemies of pea aphids (lady beetles, aphis lions, and many 
others) fail to develop in great numbers. When this occurs, corn leaf and many 
other aphids may be a problem during the warmer months. 



Leaf spots in alfalfa fields are abundant on the lower leaflets. Most of these 
are probably pseudoplea spots. Some leaflet drop can be expected from leaf spot 
infections. Fungicide control is not feasible. 

Wheat 

Septoria leaf spot on wheat is still largely confined to the lower leaves. There 
has not been much movement of the disease upward on the plants. Lower leaves are 
heavily infected in most fields and the disease could become serious if prolonged 
periods of cool, wet conditions occur. 

HOMEOWNER PEST PROBLEMS 

Trees and Shrubs 

Spring cankerworms are brown to dark- green to black measuring worms that eat the 
leaves of elm, apple, and other trees. They may completely defoliate elms. These 
worms first appear just as the leaves begin to emerge from the buds. They continue 
to feed for a few weeks; when full grown, they drop to the ground on a silken thread. 
At times, hundreds of them can be seen swinging on strands of web. 

For control, use either (1) carbaryl (Sevin) with 2 pounds of 50-percent wettable 
powder in 100 gallons of water or (2) 4 pounds of lead arsenate per 100 gallons 
of water. It is necessary to spray the entire tree. A power sprayer will be needed 
to do this. 

Eastern tent caterpillars are now common in trees, along roadsides, and in wooded 
areas in the southern part of Illinois. The worms live in the tent in the crotch 
of a tree and migrate out to the branches to eat the leaves. Strands of webbing 
or trails extend from the tent to the leaves. The easiest method of control is 
to cut out the tent and burn the branch and the tent. If this would disfigure the 
tree, you can spray with carbaryl or lead arsenate, as for cankerworms. But this 
must be done early, since it is difficult to penetrate masses of webbing with a 
spray. 

Plant Lawns 

Helminthosporium leaf spot is showing up in Kentucky bluegrass lawns. This disease 
can be very destructive during wet, cool weather- -especially on lawns that are 
mowed less than 2 inches high. The leaf spots are dark brown; some have light tan 
centers. Leaves with several spots are killed. When many leaves are killed, brown 
areas appear in the lawn. Leaf spot damage can be reduced by applying lawn fungi- 
cides containing Phaltan, Dyrene, Maneb, or Acti-dione. Applications must be re- 
peated during wet, cool weather. 

PRECAUTIONS IN USING PESTICIDES 

Corn planting has started or will start within the next few weeks. Many farmers 
will be using special insecticides designed to control aldrin/heptachlor-resistant 
corn rootworms. These insecticides are for use primarily on the soil surface ahead 
of the press wheel, not in with the seed. A few of them injure germination. Be 
sure to follow the label instructions on placement concerning these newer insecti- 
cides. 



-4- 

Also, some of these newer insecticides are more toxic than those previously used. 
You can use them without bodily harm, providing a few simple precautions are ob- 
served. The first one is to be careful, not careless. When emptying sacks of 
granules, do so in such a manner that any dust will blow away from you. Always 
wear gloves. Wear a dust mask and goggles in case of doubt. Change clothes daily. 
Always wash up carefully before eating. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, Illinois Natural History Survey and University of Illinois College of 
Agriculture. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



SPECIAL NOTICE- -NOT FOR PUBLICATION 

Last week's report had notes about insects, plant diseases, and weeds. This week, 
we have insect and plant disease information. We are trying to have a plant pest 
bulletin, rather than insects only, as part of our continuing efforts to make this 
weekly bulletin more useful to you. But we need your comments. Please send us 
your opinion. If this new style meets with your approval, we will rename this 
bulletin accordingly. Please fill out the questionnaire and return to: 

H.B. Petty, Extension Entomologist 
280 Natural Resources Building 
Urbana, Illinois 61801 

1. I want the University to continue this integration of all plant-pest information 
in a weekly situation bulletin. Yes . No. 

2. I suggest the following name for such a weekly bulletin. 



3. I am a farmer , pesticide and equipment dealer , salesman 

seedsma n , canner , newsman , other (please identify) 



Other comments: 



j~ n i 




ate / County / Local Groups 

FOR IMMEDIATE RELEASE 



fcfcv 



/ 



%. 



jfrwatfe. 



sF 



INSECT 

SURVEY 

BULLETIN. JUN io ■■:X«^ 

College of Agriculture . ,,, f 

University of Illinois 

and Natural History Survey, Urbana, Illinois 

U. S. Department of Agriculture Cooperating 

May 3, 1968 



INSECT SURVEY BULLETIN NO. 8 



This series of weekly bulletins provides a general look at the pest situation 
(fruit and aommeraial vegetables excepted) , along with suggested, abbreviated 
control measures. Each individual should check his own fields to determine local 
conditions. The plant disease report was prepared by the Department of Plant 
Pathology , the insect situation by the Department of Agricultural Entomolgy and 
the Illinois Natural History Survey, and the weed report by the Department of 
Agronomy and the Illinois Natural History Survey. 

FIELD CROP PEST PROBLEMS 



Insects 

Alfalfa weevil development has returned to normal speed, with the warmer weather 
of the past week. Egg hatch and larval feeding have greatly increased. Most 
alfalfa fields in the area south of a line from Harrisburg to Carbondale have been 
treated once, sometimes twice. Treatments should have been applied this past week 
to most alfalfa fields south of Route 50. Alfalfa stands are growing rapidly with 
the warmer weather. First cutting of alfalfa will be occurring in a week to 10 
days in the southern part of the state. In general, insecticide treatments have 
been effective in this heavily infested area. 

The alfalfa is still ahead of the weevil, especially where the first treatment was 
timed correctly. In many instances, the second treatment can be delayed until 
after cutting the first crop. Remove the first crop along with many eggs in the 
stems and treat the new growth of the second crop. 

Next week, egg hatch and larval feeding will increase in areas to the north of 
Route 50. Treatments will need to be made on some fields in the area up to a line 
through Jerseyville to Pana to Paris during the week of May 6. 

Watch for weevil feeding; when 25 percent of plant terminals show feeding, apply 
an insecticide. However, some fields may not require treatment if cut early. 
Weevil feeding will continue for another three weeks. 

The insecticide recommendations are: 

1. Experienced commercial applicators who have the proper protective clothing will 



ipplj 
th m( 



get the best results with methyl parathion applied at 1/2 pound per acre or a 
special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per acre. 
Azinphosmethyl can be applied only once per cutting . Do not harvest for 15 days 
after treatment with methyl parathion, 16 days for azinphosmethyl . 

2. The person not properly equipped with protective clothing to use methyl para - 
thTon or azinphosmethyl can use a mixture of 5/4 pound of malathion and 5/4 
pound of methoxychlor per acre (3 pints of a concentrate containing 2 pounds 



of methoxychlor and 2 pounds of malathion per gallon) or a mixture containing 
at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre (2-1/2 to 
3 quarts of the commercially prepared mixture Alfatox) . You may also use 
1-1/4 pounds of malathion per acre (1 quart of the 5-pounds-per-gallon con- 
centrate) in the morning, on days when air temperatures will be above 60° F. 
Do not harvest for 7 days after treatment with methoxychlor, diazinon, or 
mixtures of them. There is no waiting period for malathion. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The ex- 
ception is on stubble, where 10 gallons per acre by ground will be sufficient. 

Corn flea beetles are numerous in many wheat fields in western and southern areas. 
They are inflicting white scratch marks on the tips of leaves as they feed, but 
this injury is not expected to reduce yields. Although corn flea beetles are 
vectors of Stewart's disease in corn, they are not known to carry a wheat disease. 
Treatment of wheat fields is not suggested. 

Newly emerging corn should be watched for the presence of these small, shiny, black 
beetles that jump when approached. If damage to small corn is severe and plants 
are being killed, apply 3/4 pound of carbaryl (Sevin) or 1-1/2 pounds of toxaphene 
per acre as a band spray over the row. 

Spittlebugs are hatching in southern and central areas . The nymphs , orange to 
yellow in color, cause damage by sucking sap from alfalfa and clover plants. They 
are found behind leaf sheaths or on the leaves and stems, in masses of froth or 
spittle. Chemical control is usually not profitable if spittlebug nymphs average 
fewer than one per stem. 

Potato leafhoppers , a migrant from" southern states , appeared for the first time 
this week in southern areas. They are small, green, wedge-shaped insects that 
skid sideways when disturbed. They cause the yellowing on second- and third- 
cutting alfalfa. No control measures are recommended at this time. 

Variegated cutworms are feeding in clover fields in southern Illinois. Presently, 
they are very small and few in number. 

Plant Diseases 

There has not been a significant increase in the spread of Septoria leaf spot in 
wheat during the last week. The dry weather has effectively prevented the spread of 
the disease from the lower leaves to the upper ones. Spores are abundant on the 
lower leaves in nearly all fields, and the disease could become serious if periods 
of cool, wet weather occur. 

Powdery mildew is prevalent on the lower leaves and sheaths of both winter wheat 
and winter barley in fields that are about knee high (jointing). Mildew tends to 
be most severe in fields with high nitrogen fertility and high plant populations. 
This disease can be expected to increase in severity as long as moderately cool 
temperatures prevail. Rainy weather is not necessary for the development of this 
disease. The disease can be recognized by the presence of white to gray mats of 
fungus growth on the leaves and sheaths; the presence of spores gives the mats a 
powdery appearance. Effective fungicides have not been cleared for use on wheat 
and barley by the Food and Drug Administration. 



Weeds 

Oil-soluble amine formulations of 2,4-D have been available under the trade names 
Dacamine and Emulsamine. These oil-soluble amines of 2,4-D are said to have "the 
effectiveness of an ester and the safety of an amine." 

The regular esters of 2,4-D are formulated in oil and mixed with water to make an 
emulsion for spraying. The amines are salts that are purchased with the salt 
already dissolved in a concentrated solution, which is mixed with water for spray- 
ing. 

When the oily-ester formulation is mixed with water, the resulting emulsion has a 
milky appearance, with the oil globules dispersed in the water. The amines form 
a true solution, just like salt or sugar in water; so the spray mixture does not 
have the milky appearance. 

The ester formulations with oil penetrate through the waxy layer on the surface of 
leaves better than the amines. This is one of the reasons why 1/6 to 1/4 pound of 
2,4-D ester generally does about the same job as 1/2 pound of 2,4-D amine. Provid- 
ing the rate is adjusted, the amine form of 2,4-D is usually about equally effec- 
tive for killing weeds. But it is safer than the ester, since the amine is less 
volatile. 

The oil -soluble amines are similar to the esters in the way they penetrate leaf 
surfaces; hence the reason for saying they have the "effectiveness of esters." 
Since they are still amines, volatility is not a problem; hence the reason for 
saying they have the "safety of amines." 

Don't expect miracles from the oil-soluble amines. Essentially, they are just a 
different formulation of 2,4-D. Crop tolerance and the degree of weed control 
will probably be about the same as with other forms of 2,4-D, providing the in- 
dicated rates and other directions for application are followed. 

Herbicide Combinations . There's a right way and a wrong way to mix herbicide com- 
binations consisting of emulsifiable concentrates (EC) and wettable powders (WP) . 
Before you mix a large amount, test the proportions on a small scale. Some manu- 
facturers suggest this procedure: First add the EC and agitate the solution 
thoroughly. Premix the WP with a small amount of water, add it to the EC solution, 
and continue agitating the mixture. When using aldrin and atrazine together, use 
fertilizer-grade aldrin in an emulsifier; also, be careful to watch for spray line 
clogging with this combination. NOTE: This combination may be less effective than 
either aldrin or atrazine used alone, since aldrin should be disked- in immediately 
upon application for greatest effectiveness. 

Aquatic Plants in Ponds . No doubt some of the common aquatic plants, such as curly - 
leaf pondweed and small pondweed, will soon be abundant in many lakes and ponds in 
Illinois. Sago pondweed and leafy pondweed will also be appearing soon. In a 
matter of just a few weeks after the above aquatic plants first are observed in 
the water, they will severely infest much of the water space. Now is the time to 
apply herbicides for the control of these species, using such herbicides as endo- 
thall at the rate of 1 p. p.m. or diquat cation at 0.5 p. p.m. Follow label direc- 
tions. The application of herbicide prior to seed development will help reduce 
infestations in future years. Curlyleaf pondweed and small pondweed will persist 
if not treated until mid-summer. Sago pondweed and leafy pondweed will persist 
through the summer. Usually elimination of the existing stands of curlyleaf 



-4- 

pondweed, small pondweed, and sago pondweed early in the growing season will rid 
the water of these aquatic plant pests for most of the summer. Repeated applica- 
tions of herbicides may be required for the season- long control of leafy pondweed. 
Apparently, the aquatic plants can infest bodies of water throughout the growing 
season. 

HOMEOWNER PEST PROBLEMS 

Insects 

Ticks are annoying campers, picnickers, and others. Use a repellent on socks, 
pants, cuffs, and exposed parts of the body. When entering wooded or grassy tick- 
infested areas, DEET (diethyltoluamide) is one of the best tick repellents. 

To control ticks in the home yard, spray the grass, shrubs, and flowers with 
diazinon, malathion, or carbaryl (Sevin) . Do not apply diazinon to ferns or 
hibiscus, malathion to cannaert red cedar, or carbaryl to Boston ivy. 

Ants, water bugs, crickets, and other insects that commonly invade the home can 
be effectively controlled at this time of the year with a foundation treatment of 
2-percent chlordane. Purchase chlordane as an emulsion concentrate and mix with 
water to the proper strength (1 pint of 45-percent chlordane in 3 gallons of water 
gives a 2-percent solution). Spray the foundation to the point of runoff plus two 
or three inches of soil adjacent to the foundation wall. Also, spray cracks or 
expansion joints along porches and steps and along walk edges. In homes with crawl 
spaces, treat the inside wall of the foundation plus any supporting pillars. Do 
not spray on shrubbery or flowers, because the oil may burn the foliage. 

Three gallons of finished spray should be adequate for the average house. With 
this control of insects on the outside of the home, the use of insecticides inside 
the home will be greatly reduced. 

Aphids are already appearing on roses, hawthorne trees, and other shrubs. These 
soft-bodied, wingless insects usually suck the sap from new terminal leaves 
causing them to curl back. If aphids are present, spray with either diazinon or 
malathion. Mix with water according to directions on the label. This treatment 
will also control mealybugs, if present. 

Plant Diseases 

Powdery mildew is just beginning to appear in Kentucky bluegrass lawns, especially 
Merion bluegrass lawns. The disease appears first in the shaded areas under trees 
and shrubs, and on the east and north side of buildings. The fungicides Karathane 
and Parnon give excellent control when applications are begun as soon as the 
disease is seen. 

Damage from Helminthosporium leaf spot in Kentucky bluegrass is very apparent in 
some lawns in southern and central Illinois. This disease is checked by hot, dry 
weather. Fungicide applications should be continued during wet, cooler weather. 
Phaltan, Dyrene, Daconil 2787, Maneb, or Actidione are suggested. 

Weeds 

Ground ivy or creeping charlie seems to be causing more and more problems as a weed 
in home lawns. This plant, often brought in as a ground cover, escapes from the 
original beds and becomes a serious lawn weed. 



-5- 

Ground iw is characterized by a small blue flower, and a kidney-shaped leaf that 
gives off a minty odor when crushed. Ground ivy develops long runners that often 
grow beneath the grass. These runners may be raked or pulled out to keep the plant 
from running rampant. Chemical treatment with silvex, MCPP, or dicamba either 
alone or in combination with 2,4-D used at the rates recommended on the container 
should offer effective control although repeat applications may be needed for com- 
plete eradication. 



READ TEE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, Illinois Natural History Survey and University of Illinois College 
of Agriculture. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Ellery Knake and Marshal McGlamery, Department of Agronomy, J.D. 
Butler, Department of Horticulture, and Robert Hiltibran, Illinois Natural 
History Survey. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricul- 
tural Research Service, Plant Pest Control Branch. 



J./K, I 




INSECT 

SURVEY 

BULLETIN 



the Liang? ^rnr 




JUiV )Q 

mt:m Ami 

College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



ate / County / Local Groups / U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



May 10, 1968 



INSECT SURVEY BULLETIN NO. 9 



This series of weekly bulletins provides a general look at the pest situation 
(fruit and commercial vegetables excepted) , along with suggested, abbreviated 
control measures . Each individual should check his own fields to determine lo- 
cal conditions . The plant disease report was prepared, by the Illinois Natural 
History Survey, the insect situation by the Department of Agricultural Entomol- 
ogy and the Illinois Natural History Survey, and the weed report by the Depart- 
ment of Horticulture . 

FIELD CROP PEST PROBLEMS 



Forage Crops 

The alfalfa weevil continues to hold the spotlight. Economic damage is occurring 
in most alfalfa fields south of Route 40, while north of this line feeding is 
noticeable but only an occasional field has required treatment. In some fields 
south of Route 50, larval populations have doubled from what they were last week, 
but many larvae are pupating. Most fields south of Route 40 have been treated 
once and some have had two spray applications. In general, insecticide treatments 
have been effective in this heavily infested area. 

In the area north of Route 40 and south of a line from Watseka to Hardin an occa- 
sional field may need treatment during the week of May 13. 

In some problem fields where at least 25 percent of the plant terminals show feed- 
ing, apply an insecticide. But in many of the current problem fields it would be 
best to cut the alfalfa if flower buds are showing, remove the hay, and spray the 
second growth. After cutting the first crop, watch the new growth. If weevil 
damage can be seen and larvae are present, spray immediately. 

The insecticide recommendations are: 

1. Experienced commercial applicators who have the proper protective clothing will 
get the best results with methyl parathion applied at 1/2 pound per acre, or 

a special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per 
acre. Azinphosmethyl can be applied only once per cutting . Do not harvest 
for 15 days after treatment with methyl parathion, or for 16 days after apply- 
ing azinphosmethyl. 

2. The person not properly equipped with protective clothing to use methyl para - 
thion or azinphosmethyl can use a mixture of 5/4 pound of malathion and 

3/4 pound of methoxychlor per acre (3 pints of a concentrate containing 



-2- 

2 pounds of methoxychlor and 2 pounds of malathion per gallon) , or a mixture 
containing at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre 
(2 1/2 to 3 quarts of the commercially prepared mixture Alfatox) . You may 
also use 1 1/4 pounds of malathion per acre (1 quart of the 5-pounds-per-gallon 
concentrate) in the morning on days when air temperatures will be above 60° F. 
Do not harvest for 7 days after treatment with methoxychlor, diazinon, or mix- 
tures of them. There is no waiting period for malathion. 

The quantity of finished spray applied per acre is also important. Use no less than 
4 gallons per acre by air or 20 gallons per acre by ground machine. The exception 
is on stubble, where 10 gallons per acre by ground will be sufficient. 

Pea aphids are abnormally low this year in alfalfa and clover fields. 

Spittlebugs are more numerous this year. Froth masses are easily found in clover 
and alfalfa fields in the south central part of the state, ranging from 1 mass per 
10 to 20 stems. In northern Illinois, nymphs averaging 1 per 4 stems are down low 
in the leaf sheath but will soon move higher on the stems and froth masses will 
appear within the next 1 to 2 weeks. Damage so far is light. 

Chemical control is usually not profitable if spittlebug nymphs average fewer than 

1 per stem. If treatment is necessary, use 3/4 pound of methoxychlor per acre. 

Corn Insects 

Seed corn beetles have been reported causing damage to an occasional field in cen- 
tral and northern areas. The seed corn beetles (about 1/4 inch long) are brown 
with a light tan border on their wing covers or a uniform chestnut brown. The 
beetles hollow out the seed, resulting in poor germination and reduced stands. 
If replanting is necessary, apply diazinon or phorate (Thimet) as a 7- inch band 
on the soil immediately ahead of the press wheel. 

Black cutworm moths have been flying for several weeks, but there has been no 
damage reported from newly hatched larvae. Watch for damage in low, poorly drained 
areas of a field, especially where a soil insecticide was not applied. Broadcast 
applications of aldrin or heptachlor at or before planting have given good protec- 
tion against this pest. If damage appears, treat with either carbaryl (Sevin) at 

2 to 3 pounds actual ingredient per acre, or diazinon at 2 pounds, or toxaphene at 

3 pounds per acre, or trichlorfon (Dylox) at 1 pound per acre. Results will be 
improved if the spray is directed at the base of the plants, if at least 20 gallons 
of finished spray is used per acre, and if the spray is incorporated with a culti- 
vation immediately after application. 

Corn flea beetles are not yet a problem, but periodic checks of newly emerging corn 
should be made for their presence. The adults are small, smooth, black, shiny, and 
roundish, and jump readily when approached. They inflict white scratch marks on 
the first three or four true leaves and may cause the seedling to appear whitish 
or silvery and sometimes kill the plant. If damage is severe and plants are being 
killed, apply 5/4 pound of carbaryl (Sevin), or 1 1/2 pounds of toxaphene per acre 
as a band spray over the row 

Corn borer pupation reached 70 percent in extreme southern sections this week. 
Moth emergence should begin next week. Pupation is just beginning in central 
sections. 



HOMEOWNER PEST PROBLEMS 

Trees and Shrubs 

Oystershell scale eggs began hatching this week in central sections. It will be 
another 2 weeks before hatch is complete, and during this time the newly hatched 
crawlers will be setting up housekeeping on shrubs, like lilac and dogwood. Wait 
until hatch is complete before treating. Crawlers can be controlled by a careful 
and thorough spraying with malathion (2 teaspoons of 50- to 57-percent concentrate 
per gallon of water). Even though scales are killed by spraying, the scale cover- 
ing will persist for several months. 

Hawthorn leaf miner egg hatch is complete in central sections. The maggots dis- 
figure leaves and damage plants by eating the tissue between the upper and lower 
surface of the leaves. Treat immediately with malathion (2 teaspoons of 50- to 
57-percent emulsifiable concentrate per gallon of water) or diazinon (2 teaspoons 
of 25-percent emulsifiable concentrate per gallon of water) . 

Pine needle scale eggs began hatching this week in central sections. Egg hatch 
should be completed in one week. The crawlers feed in particular on white pine 
and Norway spruce. For control, spray with malathion (2 teaspoons of 50- to 
57-percent concentrate per gallon of water) . 

Juniper blight , caused by a fungus, became epidemic in Illinois in 1966 and 1967. 
Although the disease has been reported from the Midwest since the late 19th Century, 
and is widely distributed throughout the state, it seldom causes significant damage 
unless weather conditions become favorable for disease development. The prolonged 
wet, cool springs of the past two years have been nearly ideal for development and 
spread of the disease. 

The most common symptom of juniper blight is the browning or blighting of young 
shoot tips, which may appear in early May in southern Illinois and as late as 
July 1 in the northern part of the state. At the base of the brown or blighted 
tissues, very small, black fruiting bodies of the disease fungus may be seen under 
a hand lens or microscope. Spores which are formed in these fruiting bodies are 
released during wet weather and are easily spread at that time to other branches 
and adjacent healthy plants by driving rains or on pruning or shearing tools. On 
highly susceptible hosts, the fungus may invade and girdle larger stems, resulting 
in browning and death of major branches. 

Since the fungus fruiting bodies persist through the winter on the blighted shoots, 
a tremendous number of spores may be released this spring and, if weather conditions 
are again favorable for disease development, another juniper blight epidemic could 
occur in 1968. 

Several control measures, if used correctly, may be effective against juniper blight. 
All blighted twig tips should be removed and burned to eliminate the sources of in- 
fection. Pruning or shearing should be done on a dry day to reduce spread of the 
fungus to other plants by contact. In addition, susceptible plants may be sprayed 
at 7- to 10-day intervals from the time new growth begins in the spring through 
early to mid- July. Organic mercury fungicides at the rate of 1 pound or 1 pint in 
100 gallons of water will do a good job of control. Bordeaux mixture 8-8-100 or 
copper fungicides at 3 to 4 pounds in 100 gallons of water are also effective. 



-4- 
HEEBICIDES 
Special Note to Commercial Vegetable Growers 

The herbicide Prefar has been cleared for use on commercial acreages of squash, 
cucumbers, muskmelons, cantaloupes, and watermelons. Prefar should be applied 
before planting and incorporated with the soil. Use Prefar on mineral soils only 
at rates specified on the label. 

Prefar has shown excellent and sustained control of annual grasses in test plots 
in Illinois and neighboring states. Some broadleaf weeds are not controlled and 
Prefar should be used on a small part of your acreage in 1968 to fit your indi- 
vidual weed problems. Prefar also has clearance on lettuce. 

Corn 

Sales of herbicides this spring appear to have been a little more delayed than in 
the last few years. Partly caused by a little more conservative attitude on the 
part of some farmers and partly caused by some reduction in corn acreage, the in- 
crease in use of herbicides may not be as great as in recent years. 

Although many farmers have delayed their purchase of herbicides until closer to 
planting time, a high percentage of farmers are or will be using herbicides again 
this year. 

With the early planting in many areas rain could bring on a weed problem, espe- 
cially where herbicides were not used. Timely cultivation and properly timed 
postemergence applications could still keep the weeds under control. 

The rotary hoe is still one of the most effective and economical tools we have for 
controlling weeds. When the weed fuzz begins to show, it is time to go with the 
rotary hoe. Once the weed seeds have germinated and the seedlings are "in the 
white," just about ready to emerge, the rotary hoe can kick out millions of weeds 
per acre. 

If a herbicide has been used and is holding the weeds in check, there is no big 
rush for cultivation. But if the herbicide isn't working well enough, don't hesi- 
tate to use the rotary hoe. The rotary hoe isn't necessarily detrimental to the 
performance of herbicides. If the weather has been dry and one of the less per- 
sistent herbicides like Randox hasn't worked within two weeks and weeds are appear- 
ing, don't wait for miracles. If one of the longer lasting herbicides such as 
Atrazine has not worked well enough on the first crop of weeds, a rotary hoe can 
help and enough Atrazine may still be present to control later weeds. 

Postemergence Corn Applications 

If you used no herbicide or if you used a grass killer like Ramrod or Randox on 
corn, 2,4-D is still one of your most economical and effective treatments for 
broad- leaved weeds. For best control, apply the 2,4-D early when weeds are small 
and easiest to kill. You can broadcast 2,4-D over the top of corn until it is 
about 8 inches high. After that height, use drop extensions down to the nozzles. 



-5- 

If you're planning on a postemergence application of atrazine and oil, get it on 
early before weeds (including annual grasses and broadleaves) are over 1 1/2 inches 
tall and definitely within 3 weeks after planting. You may hear occasional success 
reports with applications made later than this, but delaying the application de- 
creases your chances of success and increases the chance of herbicide residue the 
next year. 

Only a few herbicides and phases of weed control are mentioned here. For more 
complete details refer to the 1968 Weed Control Guide. If you don't have a copy 
ask your county Extension adviser. 

Current issues of Agronomy News will also contain additional weed control informa- 
tion. If you are not on the Agronomy News mailing list, drop a card to Agronomy 
News, N-305 Turner Hall, Urbana 61801. There is no charge for Agronomy News. 

Soybeans 

Herbicide combinations for soybeans haven't been developed as much as for corn. 

In soybeans, Treflan primarily controls annual grasses and pigweed. It gives some 
control of lambsquarter. We don't have much of anything to combine with Treflan 
to take care of the other broad- leaved weeds. The rotary hoe is still one of the 
best bets to clean out the broad- leaved weeds, and it is not likely to decrease the 
effectiveness of Treflan. 

If annual grass such as foxtail is the major problem in soybeans, Treflan has been 
one of the most consistent performers. 

If broad- leaved weeds as well as annual grasses are a problem, amiben has a good 
record for control of many broad- leaved weeds and also does quite well on annual 
grasses. 

At this point we do not accept the economics or feasibility of combining Treflan 
and amiben, which has sometimes been suggested. 

Where annual grass and smartweed are the major problems, one possibility would be 
to incorporate Treflan before planting and follow with a regular surface- applied 
preemergence application of CIPC at planting time. For smartweed control, 3 or 
4 pounds of CIPC (active ingredient broadcast or proportionately less banded) 
should be adequate. 

Labels don't think — people do 

Be sure that your personnel deliver the right herbicides for the crop. Double 
check, especially if a corn herbicide is being moved after most of the corn is 
planted and most farmers are planting beans. All due respects to Mom, but when 
she comes in to pick up a few more bags of pesticide for Dad, be sure of the name. 
It is not too difficult to confuse names like alanap, aldrin, atrazine, and amiben 
if you are more familiar with cake recipes than with herbicides. We've already 
had some problems and could have more with farmers figuring their needs closer to 
the belt and more last-minute delivery rush this year. 



-6- 

READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, Illinois Natural History Survey and University of Illinois College of 
Agriculture. 

Plant Diseases: Donald Schoeneweiss , Illinois Natural History Survey. 

Weeds: Herb Hopen, Department of Horticulture, and Ellery Knake, Department of 
Agronomy . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 




ate / County / Local Group: 



INSECT 
SURVEY 



^ tiBRAfty 






<& 




BULLETIN^ J o^«^ 

College of Agriculture. "^ r - n, n , ntn 
University of Illinois " l % 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



May 17, 1968 



ILLINOIS INSECT. DISEASE, A ND WEED SURVEY BULLETIN NO. 10 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. The plant disease report was prepared by 
the Department of Plant Pathology , the insect report by the department of Agri- 
cultural Entomology and the Illinois Natural History Survey, and the weed report 
by the Departments of Agronomy and Horticulture and the Illinois Natural History 
Survey . 

INSECTS 



Forage Insects 

The alfalfa weevil situation has not changed greatly during the past week. The 
number of larva remains high and feeding is evident in alfalfa fields south 
of Highway 16. North of this line, feeding is noticeable but not severe. Larvae 
are pupating rapidly but eggs are still hatching, so populations are expected to 
remain high for another 2 to 3 weeks. However, no further increase in the number 
of larva is expected, rather a gradual decline should occur as pupation continues 
and the incidence of parasitism increases. (As high as 22 percent of the larvae 
were parasitized by a wasp in one field this week.) 

New spring adults are appearing in southern sections; they will feed for awhile 
in alfalfa, then move to protected places near alfalfa fields and remain quiet 
through the summer. Adult feeding damage appears as a feathering of the leaf 
margins, in contrast to the skeletonizing injury' of the larvae. Adult feeding 
damage may be more evident this year than usual, since peak emergence of adults 
is likely to occur in many fields just shortly after cutting when the new growth 
is still short. No satisfactory control is presently available for adults. 

Most alfalfa fields in the problem area have been treated at least once, some 
twice. In untreated and as yet uncut fields, it would be best to cut the alfalfa 
if flower buds are present, remove the hay, and spray the new growth of the second 
crop . Cutting itself can reduce weevil numbers, since a percentage of the unhatched 
weevil eggs are removed with the hay and many worms will be either killed or forced 
to pupate by exposure to the sun and the removal of their food supply. If the crop 
has already been cut but the new growth not sprayed, watch it closely for evidence 
of weevil damage. If it does not green-up in 2 to 5 days and worms are present, 
treat it promptly. 

On second-crop fields that have considerable growth, apply an insecticide when 

25 percent of the plant terminals show feeding. This will mainly apply to southern 

sections, where the second or possibly third spray treatment is now needed. 



The insecticide recommendations are: 

1. Experienced commercial applicators who have the proper protective clothing will 
get the best results with methyl parathion applied at 1/2 pound per acre, or a 
special alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per acre. 
Azinphosmethyl can be applied only once per cutting . Do not harvest for 15 
days after treatment with methyl parathion, 16 days for azinphosmethyl. 

2. The person not properly equipped with protective clothing to use methyl para - 
thion or azinphosmethyl can use a mixture of 5/4 pound of malathion and 5/4 
pound of methoxychlor per acre (3 pints of a concentrate containing 2 pounds 
of methoxychlor and 2 pounds of malathion per gallon) , or a mixture containing 
at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre (2-1/2 to 
5 quarts of the commercially prepared mixture Alfatox) . You may also use 
1-1/4 pounds of malathion per acre (1 quart of the 5 -pounds -per -gallon con- 
centrate) in the morning on days when the air temperatures will be above 60° F. 
Do not harvest for 7 days after treatment with methoxychlor, diazinon, or mlx- 
tures of them. There is no waiting period for malathion. 

The quantity of finished spray applied per acre is also important. Use no less 
than 4 gallons per acre by air or 20 gallons per acre by ground machine. The ex- 
ception is on stubble, where 10 gallons per acre by ground will be sufficient. 



Special note : Spray burn has occurred in some alfalfa fields with all of the 
insecticides currently suggested for use. Burn has been more apparent this year 
than last, possibly because the alfalfa in general has been taller when sprayed. 
Little or no spray burn has been observed with stubble treatments. The burn ap- 
pears first (2 to 3 days after spraying) as yellow spots on the leaves, followed 
by a more general yellowing of affected leaves. Although noticeable, the spray 
burn is usually not severe enough to affect yield. 

Meadow spittlebug froth masses are numerous, especially in many of the new clover 
and alfalfa seedings in the state. The heaviest infestation is present in the 
northern and western sections. Many small, newly hatched, orange nymphs (hidden 
behind leaf sheaths in the crown of the plants) are also present, so that froth 
masses will become even more apparent. 

To determine the need for treatment, count the number of spittlebugs (several may 
be present in a single froth mass) on 50 to 100 stems. If there are 1 or more 
nymphs per stem- -not per plant- -control is profitable. For maximum benefit, con- 
trols should be applied while the nymphs are small and just beginning to form froth 
masses. Methoxychlor applied at 3/4 pound of actual per acre will provide ex- 
cellent control. Allow 1 week to elapse between treatment and harvest or 
pasturing with methoxychlor. 

Lesser clover leaf weevil larvae can be found feeding behind leaf sheaths on red 
clover in the southern half of the state; they will appear soon in northern sec- 
tions. These small, gray to dirty-green worms eat out a groove or tunnel in the 
stem behind leaf sheaths, in the axil of the stem, or in terminal buds. Infested 
plants are often stunted; stems may wilt and die. Blooms may dry up and brown 
prematurely. Counts this week showed from 5 to 50 percent of the stems infested 
in most fields. No practical control measures are known. 



-o- 

Potato leafhoppers continue their migration into the state from the south. These 
tiny, green, wedge-shaped insects that skid sideways when disturbed cause yellowing 
of second- and third- cutting alfalfa. No control measures are needed at this time. 

Corn Insects 

Corn seed beetles are damaging germinating cornfields in the central, western, and 
northern sections. Most fields had been treated with a soil or seed treatment of 
either aldrin or heptachlor, some with other chlorinated hydrocarbon seed treat- 
ments- -indicating that seed corn beetles have probably developed resistance to 
these chemicals. This problem was observed for the first time a year ago. 

From 5 to 30 percent of the stand has been destroyed in problem fields. Seed corn 
beetles are about 1/4 -inch long, brown with a light -brown to tan border, or they 
may also be a uniform chestnut brown. They move readily when disturbed. These 
beetles hollow out the seed; the adults can usually be found in the damaged seed 
or in surrounding soil. 

If replanting becomes necessary, apply diazinon at 1 pound of actual per acre as 
a band on the soil surface just behind the planter shoe. 

Flea beetles are damaging occasional fields of corn. Newly emerging corn should 
be watched for the presence of small, shiny, black beetles that jump readily when 
disturbed and leave white scratch marks on the leaves. If damage is severe and 
plants are being killed, apply 3/4 pound of carbaryl (Sevin) --preferred on dairy 
farms- -or 1-1/2 pounds of toxaphene per acre as a band spray over the row. If 
grassy areas in fence rows, road sides, or ditch banks border the field, also spray 
these to prevent additional flea beetles from moving into the corn. Use carbaryl 
for spraying these field borders, but do not use it in the vicinity of bee hives. 
Do not contaminate fish-bearing waters when using toxaphene. 

Black cutworms are causing damage in only a few cornfields. Watch for cut plants, 
especially in the low or poorly drained spots, for the next several weeks. Ap- 
plications of 3 pounds of toxaphene, 2 to 3 pounds of carbaryl (Sevin) , 2 pounds 
of diazinon (use as granules) , or 1 pound of trichlorfon (Dylox) per acre --directed 
as a spray at the base of the plants- -will control small worms. Worms that are 
1-1/2 to 2 inches long are more difficult to control. For best results, use at 
least 20 gallons of water per acre; cultivate immediately to cover the spray deposit. 
Rain following treatment will greatly improve control results. Let's get the cut- 
worms early this year! 

Preplanting broadcast applications of 1-1/2 pounds of actual aldrin or heptachlor 
(do not use on dairy farms) per acre is the best insurance against a cutworm problem. 
Row treatments at planting time with these same insecticides provide erratic re- 
sults against cutworms. 

Corn borer pupation is complete and emergence has reached 50 percent in the extreme 
southern section. In the central section, approximately 40 percent of the borers 
have pupated. In the northern section, pupation is just beginning. 

Small-Grain Insects 

True armyworms are present in thick, rank stands of small grain (wheat, barley, 
rye) and grasses south of Highway 40. Along the north edge of this area, the 
worms are about a week old (1/4 to 1/2 inch), while south of Highway 15 the worms 



-4- 

are generally larger. Populations are generally low, but may increase as more eggs 
hatch. Cool, wet weather favors this pest. The situation will bear watching for 
the next 2 to 3 weeks. 

Do not confuse the striped armyworms with the transparent yellow-to-green sawflies . 
Sawflies were more numerous than armyworms in the wheat fields examined this week. 
Sawflies do not damage wheat plants enough to require control. 

English grain aphids can be found in wheat, but these populations are not yet 
alarmingT After the wheat heads appear (wheat was heading out as far north as 
the central section this week) , it takes an average of 30 to 50 aphids per head 
to cause measurable damage. Usually, the aphids will leave the wheat head as it 
enters the dough stage. Many lady beetles were present; they may hold aphid pop- 
ulations in check. 

The aerial spray-eradication program for the cereal leaf beetle was completed this 
week, according to Mr. Thomas Lanier, Plant Pest Control Division, Agricultural 
Research Service, USDA. The State Department of Agriculture is also cooperating 
on this program. Technical grade malathion (9.7 pounds per gallon) was applied 
by air at 4 fluid ounces per acre in a 2 -mile circle at each site where a few 
cereal leaf beetles were found last July in Will, Kankakee, Iroquois, Vermilion, 
Edgar, and Woodford counties. Over 400,000 acres were sprayed, with the hope that 
this new insect pest can be prevented from becoming established in Illinois. 

Homeowner Insect Problems 

Mosquitoes are becoming numerous in many areas of the state. To reduce the number 
of mosquitoes in your yard, follow these steps. (1) Eliminate standing water in 
such places as eaves, troughs , old tires, tin cans, children's toys, storm sewers, 
etc. (2) Apply a water-base spray containing 1-percent malathion (2 ounces of 
50- to 57-percent liquid concentrate per gallon of water) to shrubbery and tall . 
grass. Repeat the treatment every week or two if needed. (3) Keep the screens 
on doors and windows in good repair. (4) Hang plastic resin strips (2" x 10") 
containing 20-percent dichlorvos (DDVP)--one strip per 1,000 cubic feet of space, 
or about one per room. These strips will kill mosquitoes and flies for 4 to 6 
weeks. Hang the strips out of the reach of children and away from fish bowls and 
food counters. Repeat treatments with 0.1-percent pyrethrum space spray- -applied 
from a pressurized spray can- -can be used for quick knockdown in place of the 
dichlorvos resin strips. (5) When entering mosquito-infested areas, use a repel- 
lent. One of the most effective mosquito repellents is DEET (diethyltoluamide) . 
(6) For quick knockdown at cookouts, outdoor parties, or picnics, use either 0.1- 
percent pyrethrum or 0.5- to 1-percent dichlorvos (DDVP) as an oil- or water-base 
space spray. Spray the mist lightly beneath tables and chairs and into the air 
for a few feet around the area. Repeat the treatment as needed. 

Clothes moths and carpet beetles are getting ready for a summer's feast on improperly 
stored woolens. A small hole chewed in a piece of clothing may destroy its entire 
value. To keep woolens safe from damage by these insects follow these suggestions. 

1. Dry clean or wash woolens and place them in clean, plastic storage bags or other 
insect- tight containers. 

2. Woolens that are not dry cleaned or washed should be hung in bright sunlight for 
a full day and brushed thoroughly before storing. Pay particular attention to 
pocket interiors, cuffs, and folds when brushing. 



-5- 

5. If the storage area is not insect-tight (as is true of most closets, trunks, 
and boxes), vacuum the container thoroughly and spray all inside surfaces with 
0.5-percent diazinon, applied from a pressurized spray can. 

4. Cedar- lined chests are usually insect-tight, but all fabrics need to be insect- 
free before storing. The cedar oil vapors destroy small larvae, but do not 
kill the larger ones. As added insurance in cedar chests, you can spray the 
inside surfaces as suggested above or use a fumigant material. Either naptha- 
lene or PDB (paradichlorobenzene) is the fumigant commonly used in moth 
crystals, flakes, or balls. Use at least 1 pound of crystals, flakes, or 
balls for every 100 cubic feet of space. 

5. Woolens not placed in insect- free containers can be protected by treating in 
light amounts with 0.5-percent diazinon, from a pressurized spray can, or 
liberally moistened with a fluoride-base fabric solution. Protection will 
last a year or more, unless the woolens are washed or dry cleaned. Caution : 
Infants clothing should be washed or dry cleaned before use . 

6. Good housekeeping practices will help reduce the number of these insects. Clean 
frequently to prevent lint and hair from accumulating, especially around radi- 
ators, baseboards, heating vents, and closets, as well as beneath large furni- 
ture and other hard-to-get-at places. If these places become infested, a light 
application of 0.5-percent diazinon will insure protection. 

PLANT DISEASES 

New Septoria leaf spot infections are showing up on wheat plants. Some fields 
examined this week had most of the lower half of the leaves severely infected. 
The increase in this disease has occurred in the areas receiving rainfall during 
the last week. 

Powdery mildew is heavy in scattered fields throughout the state. Fields with 
high populations of plants and/or high nitrogen fertility should be watched. 
Lodging can be expected in severely mildewed fields . 

Loose smut is showing in wheat and barley fields that have headed-out. Diagnostic 
characteristic: The brown dusty mass of spores replaces the heads. The amount 
of smut varies considerably from field to field. The use of seed saved from badly 
smutted fields will result in a high incidence of loose smut the following year. 
Lower smut usually results from using certified seed as it is produced in fields 
with less than 1 percent smutted plants. 

Some alfalfa fields in east-central Illinois have been examined that show low- 
temperature injury . Hints for diagnosis: (1) leaves of the same age near the top 
of the stems killed from the tip and margins inward. (2) Older leaves showing no 
damage or lesser damage. (3) New growth from the terminals showing no sign of 
injury. The degree of injury varies from plant to plant. A period of cold weather, 
with frost, occurred one to two weeks previously. 

WEDS 

Atrazine and oil applied as an early postemergence treatment can still be used to 
get broadleaf and grass weeds, if you didn't get your preemergence herbicide on at 
planting time. 



Research and field experience suggest that on the relatively dark soils of the 
state, 2-1/2 pounds of Atrazine 80W plus a gallon of "crop" oil (non-phy to toxic) 
applied postemergence may be just as effective, sometimes more effective, than a 
preemergence application of 3-3/4 pounds of Atrazine 80W. 

On the relatively light-colored Illinois soils, a regular preemergence application 
of Atrazine will likely remain one of the most successful treatments. 

Many factors influence the results with Atrazine and oil. To control annual grasses, 
it is especially important to make the application 3 weeks after planting, when 
grasses are small (up to 1-1/2 inches). If applied too late, weed control is less 
effective and the possibility of injury to other crops next year is greater. Do 
not mix 2,4-D with the Atrazine and oil, since there is greater chance of corn injury, 

Although corn has displayed excellent tolerance to Atrazine alone, corn has some- 
times shown a general stunting where oil was added. In 1967, there were a few cases 
of fairly severe injury to corn where Atrazine and oil were used. 

Where a reduced Atrazine rate has been used in combination with another herbicide 
for preplant or preemergence application, an early postemergence Atrazine and oil 
application at a reduced rate might offer "another chance," in case control with 
the earlier treatment has not been satisfactory. But where Atrazine is applied 
twice, do not exceed the amount normally recommended for preemergence application 
for the soil type involved. 

Broadleaf weeds in lawns can be kept to a minimum this summer by the proper use of 
a starter fertilizer and by following other recommended establishment practices. 
The use of 2,4-D and 2,4-5-TP and most of the selective broadleaf weed killers are 
not recommended for newly seeded lawns. Often the first mowing will reduce the 
broadleaf weed problem enough for the lawn to look presentable. However, if the 
weeds persist after the first few mowings, 2,4-D or 2,4,5-TP may be applied for. 
effective control. 

Remember that broadleaf herbicides may damage or even kill desired plants (bent- 
grass, white clover, etc.). Pay particular attention to the container label for 
information as to what weeds will be controlled and the lawn grasses that may be 
treated safely. Follow the directions and precautions on the label. 

Filamentous algae growth often becomes apparent in many bodies of water with the 
onset of warm weather. These unsightly mats frequently drift with the wind and 
water currents. 

Applying fine crystals of copper sulfate directly to the algae mats will eliminate 
them. The copper sulfate causes the algae mats to turn white and disappear. A 
follow-up application may be necessary to completely remove all of these mats. 

The best time to apply copper sulfate is as soon as the mats appear. The mats are 
small then, less time will be required to treat them, and less copper sulfate will 
be needed. 

Another method would be to apply copper sulfate around the margins of the body of 
water, treating only the water area infested, at a rate of copper of 1 part per 
million. This method of application is also very effective. 



■7- 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy; J.D. Butler, Department of Horti- 
culture; and Robert Hiltibran, Illinois Natural History Survey. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricul- 
tural Research Service, Plant Pest Control Branch. 



m / 




INSECT 

SURVEY 

BULLETIN 



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College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



tate / County / Local Groups / U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



May 24, 1968 



ILLINOIS INSECT, DISEASE, AND WEED SURVEY BULLETIN NO. 11 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures . Each individual should check his own 
fields to determine local conditions. TflE UBRAHV OF TMF 

MAY ; 



INSECTS 



ies8 



Forage Insects 



WBVaSIY OF ILUNOtt 



The alfalfa weevil situation is about the same as it was a week ago. Damage is 
severe in some unsprayed, uncut fields, but where the first crop has been harvested, 
the second growth is growing rapidly. The big change this week is the great in- 
crease in parasitism by a wasp, one that apparently migrated into Illinois with the 
weevil. Parasitism in several fields varied from 22 to 78 percent, averaging 
47 percent for all fields examined. 

If you want to see these parasites, select large larvae and place them in a jar 
with some alfalfa. After a few days, they will build a lace-like netted globe-- 
the cocoon or shell. In some of these globes, you will see a green worm or pupa; 
in others, there will be a tiny, brown, seed-like pupa--this is the cocoon of the 
wasp parasite. 

The total effect of this parasitism cannot be assessed as yet. Parasitized larvae 
do not die in the worm stage; they die in the pupal stage. Although the larvae 
feed to maturity, they are not as ravenous as the healthy worms. Furthermore, 
parasitized larvae pupate earlier in life, cutting down on their total consumption 
of alfalfa. 

A question has been raised as to the advisability of spraying, since sprays might 
kill the parasites. If a field is about ready to harvest, cut it. If the plants 
do not show signs of growth in 2 or 3 days and weevil larvae are numerous and are 
feeding heavily, spray it. If the plants are growing, you may be able to avoid a 
spray application. 

Variegated cutworms are abundant in clover fields in the southern half of the state. 
These grey- to-black worms have a series of white-to-yellow, diamond- shaped dots 
down their backs. They are usually found in trash on the ground during the day. 
At night, they feed heavily on the lower leaves of plants and new shoots. Thus, 
the canopy of leaves on top are untouched, camouflaging the damage that is taking 
place. When the crop is cut, the worms hide under the bales or windrows. In- 
fested fields take on a brown appearance after hay removal, as the new shoots are 
being devoured. Apply 1-1/2 pounds of carbaryl (Sevin) per acre to the stubble 
after the first crop has been removed. 



Small-Grain Insects 

True armyworms can still be found in luxuriant stands of small grains and grasses 
south of Highway 40; such fields should continue to be observed. The worms are . 
still small, and it may be 10 days to 2 weeks before any damage appears. No 
serious infestations have been reported as yet. 

Sawflies , which are yellow- to-green, transparent, velvety worms, are also present 
in wheat fields, but they do no damage. These worms are not striped, as are the 
true armyworms. Furthermore, they have fleshy prolegs on every segment of the 
back half of their body, which they use for walking and grasping the surface of 
a stem securely. True armyworms have only 4 pairs of such prolegs. 

English grain aphids have appeared in numbers in a very few fields of small grains 
in western and southwestern Illinois. They may increase with continued cool 
weather . 

Cereal leaf beetle detection surveys are now or soon will be conducted in the 
northern two- thirds of the state. Representatives of the state and federal govern- 
ment will be examining small-grain fields, particularly oats, for this new foreign 
pest. A few specimens have been found in Illinois during the past two years. 
These scouts will contact your University of Illinois county Extension adviser be- 
fore the survey begins. 

Corn Insects 

Corn seed beetles are abundant in some fields. Damage is reported from fields 
treated with aldrin or heptachlor, indicating resistance. Under adverse conditions 
for germination, damage will be more serious than when conditions favor rapid 
germination. 

Most damage occurs in end rows and for a short distance into full-size field rows. 
The entire field is not usually affected. Furthermore, some seeds in dry soil 
or that were planted too deep have not germinated; do not confuse this lack of 
germination with beetle injury. Examine kernels for beetle injury- -if there is 
none, the seeds may still germinate. Furthermore, do not disk-up a reasonably 
good stand- -it might still produce more corn than a later planting. 

When replanting, you may need one of the insecticides used for corn rootworm con- 
trol, applied as a band on the soil surface ahead of the press wheel. We suggest 
1 pound of diazinon per acre, but other rootworm insecticides may also give con- 
trol. When replanting, consider the conditions; if they favor rapid germination, 
treatment may not be necessary. 

Wireworms have damaged a few fields of corn already. No insecticide had been 
used. Although it is difficult to control these pests after corn is planted, a 
spray of aldrin or heptachlor may greatly retard further damage. Apply 1 pound 
of the actual chemical per acre; direct the spray at the base of the plant. Cul- 
tivate immediately, then hope for about an inch of rain to help carry the insec- 
ticide down to the wireworms. Do not use aldrin or heptachlor on dairy farms; 
try diazinon. 

Black cutworms may soon appear. Watch low spots in cornfields. When the first 
plants are cut, get ready to apply an insecticide while the worms are still small 
and can be controlled. Applications of 3 pounds of toxaphene, 2 to 5 pounds of 



carbaiyl (Sevin) , 2 pounds of diazinon (use as granules) , or 1 pound of trichlorfon 
(Dylox) per acre- -directed as a spray at the base of the plants--will control small 
worms . 

For best results, use at least 20 gallons of water per acre; cultivate immediately 
to cover the spray deposit. A rain following the treatment will greatly improve 
control results. 

Homeowner Insect Problems 

Elm leaf beetle eggs were found this week on Chinese elm. These eggs are yellow, 
formed in clusters on the undersides of the leaves. The yellow larvae that will 
hatch from the eggs feed on the undersides of the leaves. The leaves appear 
silvery at first as the green tissue is eaten; but soon, the entire tree will take 
on a brown appearance. It is still too early to spray, but they are starting. 

PLANT DISEASES 

Septoria leaf blotch , formerly found only on the lower leaves, has now moved up 
on wheat plants. In some fields, as many as 50 percent of the leaves are showing 
infection; some are turning brown. Such leaf damage makes the field appear brown 
and thin. If the grain is only slightly developed, leaf loss will result in 
shriveled, light grain at harvest. 

Powdery mildew is now common in wheat fields in many areas of the state. Fields 
with moderate -to -severe infections are beginning to lodge. 

Yellow dwarf has appeared in a very few oat fields in southwestern Illinois. Where 
present, the infection is severe, and damage will be serious. 

WEEDS 

For broadleaved weeds in corn, 2,4-D is still your most effective and economical 
herbicide. You can broadcast over the top until corn is 8 to 10 inches high. 

Rates suggested for broadcasting 2,4-D per acre are 1/6 pound of the low-volatile 
ester, 1/4 pound of the high-volatile ester, or 1/2 pound of the amine. For most 
weeds, the earlier you apply, the better the control. 

Nutgrass infestations have increased the past few years. We don't have all the 
answers for control yet, but Vernam looks like a good bet where you plant soybeans. 
As an early postemergence agent in corn, atrazine and oil has given partial con- 
trol of nutgrass; it may give enough knockdown to permit better smothering with 
the cultivator. 

Aerial application of atrazine may give weed control in cornfields that are too 
wet to cultivate. However, unless applications are accurate and uniform, residue 
problems may occur next year, if there is much overlap. 

How late can preemergence herbicides be applied if they were not put on at plant - 
ing time? This depends on the herbicide. Atrazine can be applied anytime up to 
3 weeks after planting- -until weeds are 1-1/2 inches tall. Ramrod may have some 
effect on very small weeds, if applied very soon after emergence. But your best 
bet for most preemergence herbicides is to apply them before the weeds emerge- - 
usually at planting time or very soon thereafter. 



We know you never make mistakes , but just in case you goof and get the wrong her- 
bicide on the crop, don't panic. The seriousness of the problem will depend on the 
crop and herbicide involved. If you have a 50-50 chance of crop recovery, you 
might consider replanting between the rows of the first planting, then saving which- 
ever planting looks best in a few weeks. The use of a herbicide on a crop for which 
it is not cleared poses another problem. 

Planavin has received clearance for the use of up to 1-1/2 pounds of active in- 
gredient (2 pounds of 75-percent wettable powder) on a broadcast basis for soybeans. 
The previous maximum was 1-1/8 pounds active (1-1/2 pounds of 75-percent wettable 
powder) . 

How deep you incorporate herbicides will depend on many factors, such as soil 
texture, speed, and the adjustment of the equipment. As a rule of thumb, most of 
the herbicide is usually incorporated only about a third to a half of the depth 
to which equipment is operated. Excessive incorporation may dilute the herbicide 
and decrease weed control. If incorporation is too shallow, loss of volatile her- 
bicides may increase. Follow the manufacturer's directions; he is as anxious as 
you are for the herbicide to work. 

If you have to replant and have used a herbicide, analyze your situation carefully. 
If you used Randox on corn, you could replant to soybeans with no problem. If you 
used atrazine on corn, don't replant to soybeans, you can replant to corn and still 
receive some benefits from the atrazine already in the soil. For other situations, 
review the characteristics of the herbicides, such as persistence, crop tolerance, 
and clearance. 

However, you might apply a herbicide when replanting, but weeds usually aren't as 
much of a problem on late planting. Good cultivation may be all you will need. 

Two general groups of cattails, narrow- and broad- leaf, are found in Illinois water. 
The narrow- leaf cattails have narrower and smaller leaves but longer seed stock 
than the broad- leaf cattails. If the two species are present together, crosses 
can also be present. 

The elimination of these two cattail species with herbicides is easily possible, 
and the same herbicides are effective against both. Also, herbicides applied 
prior to the development of the cattail head will help prevent spread. 

Cattail control can be undertaken by applications of dalapon or aminotriazole to 
the foliage; use 4 ounces of dalapon or 2 ounces of aminotriazole per gallon of 
water. The effectiveness will be increased by the addition of some liquid house- 
hold detergent. A second application may be necessary to eliminate the plants 
that survive the first application. Hand-pulling the new shoots will prevent 
regrowth. 

In controlling cattails, remember that they help prevent bank erosion, and thereby 
have some benefit. 

SPRAY EQUIPMENT 

With equipment for applying fungicides, herbicides, and insecticides, nozzle wear 
is especially important. Experimental tests show that the flow rate of nozzles 
increases 25 percent after being used on 500 acres. Such a 25-percent overdose 



may be serious, so recalibrate your sprayer after every few hundred acres. Be 
sure you know the amount of any chemical you are applying, and be certain that the 
amount you apply agrees with the recommended rate. 

If you set the speed for applying chemicals by positioning the tractor speed- 
control lever, also check this --particularly after the recent rains. Harder soil 
surfaces will result in a higher ground speed, even though the speed-control lever 
setting is the same. To determine speed, check the time in seconds it takes to 
drive between markers 88 feet apart with a running start. Your speed in miles per 
hour is the number of seconds divided into 60. 

A water hose in the spray tank may result in back siphon into the well. To avoid 
this, fix a bracket on your spray tank to hold the hose above water level when 
filling. This will eliminate the possibility of a hose stuck down in the tank 
siphoning pesticide into a well. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Crops, Ellery Knake, Department of Agronomy; Aquatic, Robert Hiltibran, 
Illinois Natural History Survey. 

Spray Equipment: J.C. Siemens, Department of Agricultural Engineering. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricul- 
tural Research Service, Plant Pest Control Branch. 




INSECT 
SURVEY 






THE LiBRABY OF THt % 



M 



BULLETIN jun ifcm^ 

College of Agriculture ^ pj [UMS 

University of Illinois ' 

and Natural History Survey, Urbana, Illinois 



itate / County / Local Groups 

FOR IMMEDIATE RELEASE 



U. S. Department of Agriculture Cooperating 

May 31, 1968 



ILLINOIS INSECT, DISEASE, AN D WEED SURVEY BULLETIN NO. 12 

This series of weekly bulletins provides a general look at the insect, -plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 

INSECTS 

Corn Insects 

Corn seed insects continue to destroy stands of newly emerging corn. Some fields 
being destroyed for a second time will need to be replanted again. Circumstantial 
evidence indicates that both the seed corn beetles and maggot are resistant to the 
chlorinated hydrocarbon insecticides in these problem fields . How widespread this 
resistance may be has not been determined as yet, but several dozen fields are 
known to have problems. 

Preliminary observations in test plots (replanted and treated a week ago) indicate 
that the organic phosphate insecticides used for control of resistant rootworms 
will effectively control corn seed beetles. For the present, if replanting be- 
comes necessary, we suggest applying 1 pound of actual diazinon per acre as a band 
on the soil surface just ahead of the press wheel. Take time to consider before 
disking -up a reasonably good stand- -it might still produce more corn than a later 
planting . 

Corn rootworm eggs will be hatching soon. Resistance by northern corn rootworms 
to aldrin and heptachlor has become widespread in the northern half of the state. 
The western corn rootworm, which is highly resistant to these same insecticides, 
will cause commercial damage in some fields in the area west of a line from Galena 
to Dixon to Peoria to Carthage. Potentially, any field planted to corn for 3 or 
more years (in some cases even second-year corn may be affected) in the northern 
half of the state could have moderate-to-severe lodging from rootworm attack this 
summer. 

If you suspect or know that you have resistant rootworms and if you did not use 
an organic phosphate or carbamate insecticide at planting time, apply an organic 
phosphate insecticide within the next two weeks. Use granules applied at the 
base of the plants, and cover them by cultivation. Diazinon, disulfoton (Di- 
Syston) , or phorate (Thimet) at 1 pound of actual chemical per acre have label 
approval and are suggested for use. If you have not yet planted your corn and 
wish to control rootworms, apply diazinon, Dyfonate, BUX-ten, Dasanit, or phorate 
as granules at 1 pound of actual chemical per acre in a 7 -inch wide band lust 

IHE LIBRARY OF THI 

JUii 3 u.,, 

UNIVERSITY OF ILLINOIS* 



ahead of the press wheel. Always handle insecticides with care; be especially 
careful when handling Dyfonate, Dasanit, and phorate--all are highly toxic in- 
secticides. Read and follow the precautions on the label. 

Black cutworms are just beginning in a few scattered fields. The recent wet 
weather should favor cutworm development. Continue to watch the low, poorly 
drained spots or places where water stood during recent rains for signs of cut- 
worm damage. Fields treated before planting with a broadcast application of 1-1/2 
pounds of actual aldrin or heptachlor per acre are the least likely to have problems 

For emergency control, applications of 3 pounds of toxaphene, 2 to 3 pounds of 
carbaryl (Sevin) , 2 pounds of diazinon (use granules) , or 1 pound of trichlorfon 
(Dylox) per acre- -directed as a spray at the base of the plants- -will control 
small worms. For best results, use at least 20 gallons of water per acre; culti- 
vate immediately to cover the spray deposit. A rain following the treatment will 
greatly improve control results. 

European corn borer moth emergence has reached 75 percent in the southern section; 
pupation is about complete in the central section; and it is at the 55-percent 
level in the northern section. The generally low number of overwintering corn 
borers (half those of a year ago) make the possibility of serious problems with 
first-generation borer rather remote. In addition, with the large acreage of 
early planted corn, moths will be spreading their eggs over many fields rather 
than just concentrating them in a few. The greatest possibility of injury to a 
few fields by first-generation corn borer is in the west-central, west, and west- 
southwest sections- -areas where overwintering populations were highest. Be pre- 
pared to examine early planted fields in late June and early July in these areas 
for borer feeding. 

Forage Insects 

Alfalfa weevil populations have leveled off and are beginning to decline as larvae 
pupate, parasites take their toll, and overwintering adults lay fewer eggs. The 
new growth of the second crop may still need to be sprayed in some fields. 
Although larvae will be present and easily found in most fields for several weeks 
yet, the peak period of damage is over. 

Newly cut alfalfa fields south of a line from Watseka to Hardin should be checked 
for possible damage. If a field does not green up in 2 or 3 days after cutting 
and if worms are present, treat it promptly. 

For control of alfalfa weevil larvae, farmers making their own applications should 
use either malathion or a commercially prepared methoxychlor-malathion or 
methoxychlor-diazinon (Alfatox) mixture. Commerical applicators can use the above 
materials or one of the more-toxic insecticides like methyl parathion or azinphos- 
methyl (Guthion) . Be sure and follow label directions for dosages, harvest limita- 
tion, and precautions when using insecticides. 

Mead ow spittlebug froth masses are thick; some fields may justify treatment. New 
seedings of clover and alfalfa in the north and western sections are the most- 
heavily infested. If there are 1 or more nymphs per stem- -not per plant- -control 
is profitable. Methoxychlor applied at 5/4 pound of actual chemical per acre 
gives excellent control. With methoxychlor, there is a 1-week waiting period be- 
tween treatment and harvest or pasturing of the crop. 



Potato leafhoppers continue to migrate into the state from the south, laying eggs 
in alfalfa. These small, green, wedge-shaped insects that skid sideways when dis- 
turbed cause yellowing of second and third cuttings. They not only reduce yields, 
but also lower the vitamin A and protein content of the hay. Populations appear 
to be heavier than normal; damage could be more pronounced this year. 

Leafhopper abundance can be detected by shaking the plants over a piece of paper. 
If swarms of these insects are observed at cutting time, treatment of the new 
growth is indicated. Spray when the new growth is 2 to 6 inches tall with either 
1 pound per acre of actual carbaryl (Sevin) or methoxychlor . Allow 7 days to 
elapse between treatment and harvest when using methoxychlor. There is no waiting 
period for carbaryl. 

Small-Grain Insects 

The number of true armyworms remained low in the fields observed this week, and 
it appears that this may be a light year for them. The worms found in the central 
and south-central sections were about 1/2 to 1 inch in size, with the highest 
counts in thick, rank, lodged spots averaging about 1 per foot of row. No reports 
of control applications have been received at this time. 

English grain aphid populations have increased in wheat, particularly in the west- 
southwest and southwest sections. Counts range as high as 20 aphids per head. 
It takes an average of 30 to 50 aphids per head to cause measurable damage. Make 
a careful count, taking head samples in several areas of the field to obtain an 
average figure. If control is indicated, have a commercial applicator apply methyl 
parathion at 1/4 pound of actual chemical per acre. There is a 15-day waiting pe- 
riod between treatment and harvest for methyl parathion. 

Homeowner Insect Problems 

Bagworm hatch is now complete in southern sections, and sprays should be applied 
immediately. The target date for spraying in the central sections is after 
June 15; in northern sections, after June 30. 

Make plans to apply treatments early this year, while the worms are still small 
and easy to kill and before damage is evident. Carbaryl (Sevin), diazinon, or 
malathion are all effective. Malathion will also provide fair control of mites 
that might be present. Follow label directions and check the plants that may be 
injured if sprayed with the insecticide you are using. 

Oystershell scale hatch is about complete in the central and southern sections ; 
sprays will control them if applied during the next few weeks. In northern sec- 
tions, sprays should not be applied until after June 15, when hatch is complete. 
Careful and thorough spraying with malathion (2 teaspoons of 50- to 57 -percent 
liquid concentrate per gallon of water) will effectively control oystershell scale. 
An additional treatment will likely be needed in early to mid-August for second 
generation crawlers. Even though scales are killed by spraying, the scale cover- 
ing will persist for several months. 

Chiggers will be a problem soon. They annoy campers, hikers, picnickers, fisher- 
men, and berry pickers--even homeowners in their own yard on occasion. When enter- 
ing possible chigger- infested areas, use a repellent such as DEET (diethyl toluarnide) 






-4- 

Take a warm soapy shower or bath as soon as possible after returning from a chigger- 
infested area. It takes the mites several hours to penetrate the skin; they can 
often be washed off before becoming embedded. 

To reduce chiggers in a home yard, spray lightly over the grass, low flowers, and 
shrubs with either malathion or diazinon. 



PLANT DISEASES 



Wheat 



Septoria leaf blotch has increased during the last week. Lesions may be found on 
all leaves in fields in southern Illinois. The leaves on the lower half of the 
plant are usually dead. The incidence of septoria is less as you go north in the 
state. Damage by septoria can be expected to increase during the next week or 
10 days if the weather remains moderately cool. 

There has been relatively little change in the amount of powdery mildew . Although 
scattered in occurrence, this disease is present in some fields in sufficient 
quantity to cause lodging. 

Leaf rust and stem rust can be found on susceptible wheat varieties south of 
Highway 40. Rust has not been observed on Benhur or Riley 67. Trace amounts 
have been found on Triumph and Monon. Uniform light leaf rust has been found in 
Gage wheat. 

Oats 

Yellow dwarf in oats has been found only in the extreme southwestern part of Illi- 
nois. If aphid populations increase in other parts of the state, oat fields 
should be watched for this disease. 

Corn 

Cold-weather damage to corn has been reported in northern Illinois. 

WEEDS 

Ducks and Herbicides 

The excessive moisture we have had in some areas may be fine for ducks, but what 
about herbicide performance? 

With normal seedbed preparation and fairly loose, open soil, herbicides are usually 
moved into the soil with initial rainfall. There probably wasn't much lateral 
movement across the soil surface, unless herbicides were applied to a compact smooth 
surface that wouldn't let the herbicide in easily. The torrents of rain that moved 
soil in some places may also have caused some herbicide movement with the soil. 

With excessive rain, the more-soluble herbicides like Randox may be moved too deep-- 
past the zone where they are most effective. Ramrod is less soluble (700 parts 
per million) and not as subject to leaching as Randox. Atrazine is one of the 
least-soluble herbicides for corn (70 p. p.m.). Other factors (soil texture, soil 
structure, temperature, and degree of adsorption onto the soil complex) will also 
affect the rate of herbicide loss. 



-5- 

Treflan is one o£ the least-soluble herbicides (less than 1 p.p.m.). But with 
excessive moisture degradation, certain chemical or biological processes in the 
soil may be increased. As soil moisture moves up to the surface and evaporates, 
some herbicide may move upward with the moisture and might be relocated in the 
effective zone. Or some may move with the water vapor into the air. 

Your best indication of how much herbicide you have left is to check on how good 
your weed kill is. If you used a preemergence herbicide and it's working, count 
your blessings. But if weeds are growing, don't hesitate to cultivate as soon as 
you can- -even though you used a herbicide. Weeds may sometimes emerge and then 
die, but don't wait too long if you could be cultivating. 

With the sun coming out, crusting may be a problem on some fields. The rotary 
hoe is still one of the best implements for breaking crusts and killing early 
weeds. For weeds that are too far along for the rotary hoe, the row cultivator 
is one of your next lines of defense. 

Postemergence herbicides may help, especially on large acreages or where it's too 
wet to cultivate. If you haven't used any atrazine on the field yet and you don't 
think cultivation or 2,4-D is the answer, consider atrazine and oil . 

If you used a half rate of atrazine with Ramrod preemergence on dark soil and if 
Ramrod isn't holding the grass, consider another half rate of atrazine with oil. 
Weigh the cost against possible loss due to weeds. 

For most broadleaved weeds, 2,4-D is still your best bet for postemergence applica- 
tion. Atrazine plus oil can help on both broadleaved and grass weeds that are less 
than 1-1/2 inches tall. Lorox or Dowpon are possibilities a little later for 
directed postemergence application in corn, but you will need special equipment 
and a lot of care in application. 

We haven't been overly optimistic about aerial applications of atrazine and oil. 
But they may help out in emergency situations, where fields are wet and it looks 
as if the weeds will get too large for cultivation. If you decide on aerial appli- 
cation, insist on as uniform an application as possible. Avoid overlapping that 
can cause residue problems. It will be difficult to eliminate overlap completely. 
If you use an aerial application of atrazine, plan on corn in treated fields again 
next year. Don't use more than 2-1/2 pounds per acre of Atrazine 80W, and be sure 
to keep atrazine off crops other than corn. 

Make your decisions and control weeds as early as possible. We don't have any 
good answers for knee-high grass in corn and soybeans. 

Atrazine and Oil 

Atrazine and oil can help control weeds when it's too wet to cultivate, but users 
should realize that corn can sometimes be injured. This may be a good year for 
killing weeds with atrazine and oil. But adding oil to atrazine can increase the 
possibility of injury to corn. Last year, some corn showed early stunting but 
usually recovered well. There were a few cases of fairly severe injury. With 
the cool and wet weather, corn is growing slowly and is already under stress. 
Applying oil may further reduce respiration, resulting in some injury. However, 
when it warms up and plants are growing rapidly, entry into the plant may be 
greater, also creating some possibility of injury. 



-6- 

Weeds can also be a serious threat, so carefully weigh the advantages and dis- 
advantages of using atrazine and oil. If you decide on atrazine and oil, be will- 
ing to accept the risks involved as well as the benefits. You can reduce risks as 
much as possible by making uniform and accurate applications. 

Marginal Aquatic Plant Control 

Several species of aquatic plants inhabit the shorelines of many bodies of water. 
Frequently, the entire shoreline is infested (depending upon the water depth) , 
and the plants can form borders along the water edge. Also, the marginal plants 
can infest much of the area where there is shallow water. 

Marginal plants --arrowhead, waterwillow, creeping water primrose, and bulrushes -- 
can be controlled by applications of granules 2,4-D at a rate of 1 pound of 20- 
percent granuler 2,4-D per 440 square feet. Also, foliar applications of liquid 
2,4-D using 1/4 cup (4 pounds per gallon ester of 2,4-D) diluted to 1 gallon with 
water is very effective for the above species. 

However, these plants also help prevent erosion along the bank of the pond, thereby, 
they are of some value. 

LISTING OF LICENSED ILLINOIS CUSTOM SPRAYER APPLICATORS 

If you would like a list of persons having an Illinois Custom Spray Applicator's 
License, you may obtain one by writing to Mr. Juett Hogancamp, Weed and Herbicide 
Adviser, State Department of Agriculture, Emerson Building, State Fairgrounds, 
Springfield, Illinois 62705. County Extension advisers already have one copy of 
this list. 

NOT FOR PUBLICATION: SPECIAL NOTE TO RADIO AND TELEVISION STATIONS 

If you inadvertently misplaced or lost the number to our automatic telephone- 
answering service, it is as follows: (217) 333-2614. Have your recorder running 
when you call. The answering device will play a 1:40 tape, summarizing the week's 
insect activity and forecasting the next week's problems. If you are in the 
northern-half of Illinois , call between 9 a.m. and 11 a.m. each Friday; if you 
are in the southern-half of the state , call between 11:05 a.m. and 1 p.m. Contact 
your county Extension adviser in agriculture for the local angle. 

For more information, or in case of difficulty, call Mr. Cliff Scherer in the Agri- 
cultural Communications Office, 330 Mumford Hall, University of Illinois, Urbana: 

(217) 333-4783. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy; Robert Hiltibran, Illinois Natural 
History Survey. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 




INSECT 

SURVEY 

BULLETIN 

College of Agriculture 

University of Illinois 

and Natural History Survey, 






tate / County / Local Groups / U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



June 21, 1968 



ILLINOIS INSECT, D ISEASE, A ND WEED SURVEY BULLET IN NO. 15 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local ^"^fjffc^'ft^inv nr rur 



Corn Insects 



jul rtW 

WKWMitlT tt RUNS* 



Corn rootworms are of primary concern this week. We have found a few newly - 
hatched western rootworm larvae and had a report of northern rootworm egg hatch 
on June 2TT! Rootworms should be found commonly within the next 10 days. 

All western corn rootworms in Illinois are highly resistant to aldrin and hepta- 
chlor"] The area of moderate to severe western corn rootworm infestation is bounded 
in Illinois by the Mississippi River on the west and a line from Carthage to Peoria 
to Dixon to Galena on the south, east, and north. In this area, third-year corn- 
fields are likely to be damaged and second-year fields may very well be severely 
damaged by western rootworms, particularly in Mercer County and adjacent areas. 
Over 50 percent of the fields infested by northern corn rootworms in 1967 showed 
varying degrees of rootworm resistance to aldrin and heptachlor. Although these 
northern corn rootworms are present throughout the state, they are expected to be 
more severe in the northern half of Illinois than in the southern half. Fields 
planted to corn for 3 or more years continuously are most likely to be damaged, 
but severe damage to second-year corn may occur. The farther north and west the 
more common the northern corn rootworm is and the more resistant it has become. 

At planting time, many farmers used one of the phosphate or carbamate insecticides 
in places of aldrin or heptachlor to control these rootworms. Many other farmers 
have planned to use one of these phosphate or carbamate insecticides as a basal, 
cultivator, or lay-by application. The insecticide is directed at the base of the 
plant and the cultivator throws dirt over the chemical . We recommend 1 pound of 
diazinon, disulfoton (Di-Syston) , or phorate (Thimet) per acre. BUX ten, Dasanit, 
and dyfonate do not have label approval for this purpose. Parathion and carbaryl 
(Sevin) , although not recommended in Illinois for this purpose, do have label ap- 
proval and are recommended by some states . 

For convenience, this can be done any time in the fore part of June, but the ideal 
ti^e to apply these chemicals as basal treatments is when the first rootworm eggs 
begin to hatch and that is now. Another week and it will be impossible to get 
through some fields. For those farmers who have already made these applications, 
the control should be very good. 



Several have called to ask about determining need for this basal application. If 
the field was treated with aldrin or heptachlor last year, the corn lodged badly, 
and the roots were devoured, then you probably had resistant rootworms. If you 
found green beetles feeding on the silks of each ear, you have a rootworm problem. 
Corn planted in these fields this year will probably be damaged, and you should 
be ready to apply or already have applied control measures. But you can make a 
basal application even after rootworm hatch has begun, providing you can get 
through the field with your equipment. Ideal time for application is now, not 
after the damage has been done. It will be too late 2 to 3 weeks from now. 

Black cutworms continue to appear in a few fields but only a few are present. 

For emergency control, applications of 3 pounds of toxaphene, 2 to 3 pounds of 
carbaryl (Sevin) , 2 pounds of diazinon (use granules) , or 1 pound of trichlorfon 
(Dylox) per acre --directed as a spray at the base of the plants --will control 
small worms. For best results, use at least 20 gallons of water per acre; cul- 
tivate immediately to cover the spray deposit. A rain following the treatment 
will greatly improve control. 

White grubs are now being reported from a few corn and soybean fields. These 
fields are usually those where beans Avere grown in 1967. The June beetles, adults 
of the white grubs, deposit their eggs in bean fields in a continual corn-soybean 
rotation. The eggs hatch and by the following year the grubs are about 1/4 inch 
long. We are in the second year of this cycle, and these grubs will feed all 
summer. 

If the field is in soybeans, we have no chemical control after the beans are up. 
In corn, it might help to apply a spray of 1 pound of aldrin or heptachlor. Direct 
the spray at the base of the plant. Cultivate immediately and throw dirt over the 
sprayed area. This will provide some help but control will not be perfect. 
Whether or not this specific use has label approval is open to question, but the 
corn should not be used for ensilage or stover. The grain should be free of any 
contamination, however. This should not be applied after early July. 

First-generation European corn borers are not expected to be a general problem 
this year even in the more advanced fields in an area. However, it would be wise 
to check the most advanced fields to be sure that a localized situation has not 
developed. 

Based on borer development, time for treatment in west -southwest and west-central 
Illinois will be the week of June 24 and for north-central and northern Illinois 
the week of July 1 . 

To decide whether an insecticide can be profitably applied, measure the tassel 
ratio of the field and determine the percentage of the plants with recent feeding 
in the whorl leaves. To determine the tassel ratio, measure the height of the 
plants with leaves extended; split the stalk open and measure from the tip of the 
developing tassel to the base of the plant; divide the tassel height by the plant 
height; and multiply by 100. That figure is the tassel ratio. If the tassel 
ratio is at least 55 (preferably 40 to 45) and at least 75 percent of the plants 
show whorl feeding, treatment is justified. Use 1 pound of actual diazinon in 
granular form per acre or 1 1/2 pounds of carbaryl (Sevin) as granules. For 
spraying, use the sane amount of actual insecticide per acre, and direct the spray 



to the upper third of the plant. Aerial applications should be granules, not 
sprays or dusts. Allow 10 days between treatment and ensiling of corn when ap- 
plying diazinon; carbaryl has no waiting period. Recent label approval has been 
granted for use of 7 1/2 to 10 pounds of 20 -percent carbaryl granules per acre. 
Our tests some years ago were with 5 -percent granules, but we would anticipate 
similar control results. 

Soybean Insects 

Variegated cutworms have been found damaging soybeans. This almost black to gray 
worm has a series of yellow or white diamond spots down its back. It feeds at 
night and hides in the soil during the day. Carbaryl (Sevin) as a spray at 1 
pound per acre should give practical control. 

Small Grain Insects 

Cereal leaf beetles have been tentatively identified (not yet officially confirmed) 
this year from Cook, Champaign, Edgar, Kankakee, Grundy, Shelby, Livingston, 
Vermilion, and Will counties. They have not been found in Woodford and Iroquois 
counties this year but were found in these two counties in previous years. This 
foreign insect is a pest of oats and spring wheat and has been a problem in 
northern Indiana and northern Michigan for the past few years . 

Honey bees 

Under some circumstances, use of insecticides on foliage can kill large numbers of 
bees needed for pollination of many crops. This represents a loss to the farmer 
who was using the insecticide to kill noxious insects. Bee kills also work a 
financial hardship on the beekeeper. However, beekeepers and farmers can both 
benefit by cooperation when insecticides are to be used. 

Insecticide use can very well be of benefit to bees. Insecticides kill insect 
pests and allow more plants to grow and bloom, thus increasing pollen and nectar 
supply for the bees. 

Selection of insecticide and formulation may greatly reduce or eliminate bee losses. 
Some insecticides are quite toxic to bees, others moderately so, and others only 
mildly toxic. Some are persistent, others are not. A toxic insecticide applied 
as a granule may have little effect on bees frequenting the field, while a spray 
or a dust of the same insecticide may be quite toxic. Both beekeepers and appli- 
cators should know the properties of the insecticide and the formulation to be 
used. Farmers should notify beekeepers prior to use of insecticides, giving 
enough notification that the beekeeper can handle his bees properly. 

The beekeeper should know the agricultural practices in the neighborhood of his 
bee hives. At critical times of insecticide use, he may be able to cover the 
hives or under some circumstances move them temporarily to another location. Bee- 
keepers can help by posting their name and address on bee yards. They can also 
supply the county Extension adviser with a list of beekeepers in the area and 
locations of hives. 

With a little care bee losses in Illinois can be of minor importance. For further 
information, ask your county Extension adviser for a copy of University of Illinois 
Circular 940, "Pesticides and Honey Bees." 



Livestock Insects 

Flies on pastured cattle are increasing in number and are causing noticeable an- 
noyance to the animals. In southern sections, there is an average of 40 to 250 
horn flies and 2 to 4 stable flies per animal. In northern sections, there is an 
average of 25 to 50 horn flies, 1 to 3 stable flies, and 2 to 10 face flies per 
animal. 

Start fly control rather than waiting until the problem is severe. Thus far, 
weather has been favorable for high survival of stable flies and maggots which 
forecasts a severe fly year. Stable flies prefer wet and rotting straw in which 
to deposit eggs, as their maggots survive very well in this material. If the 
weather remains moist and humid throughout the summer, stable flies will even 
develop in moist rotting vegetation in fence rows and fields. Piles of discarded 
hay or grass clippings also provide an incubator for these stable flies. 

Right now remove wet straw and hay from the barns and barn lots. Scatter it to 
dry before the stable flies use it as their egg incubator. A bit of sanitation 
now may prevent a severe problem later. 

For dairy cattle, apply Ciodrin, dichlorvos (DDVP) , or synergized pyrethrin sprays 
daily or twice a week depending on amount used per animal. For beef cattle, use 
toxaphene every 3 weeks or Ciodrin in an automatic sprayer. Do not apply toxaphene 
within 28 days of slaughter nor to calves under 4 months of age. 



PLANT DISEASES 



Corn 



Corn smut has killed young plants in some fields in central Illinois. The damage 
occurs only in the low areas of fields . Stand reductions in the damaged areas of 
as much as 50 percent have been observed. The smut infection occurs below the 
soil line and results in typical white smut galls on the base of the plant. The 
above-ground symptoms are: (1) stunting of the entire plant, (2) wilting of the 
leaves followed by death of leaves, and (3) death of the plant. Some galls ex- 
tend above the soil line and cause considerable distortion of the plant. This 
can be distinguished from herbicide injury by the presence of the smut galls. 
There apparently is no evidence that herbicides predispose the plants to infection. 
Damage to corn seedlings by smut is a little unusual; however, such injury was 
noted in Indiana last year and again this year. 

Wheat 

Leaf rust has increased rapidly during June and is very heavy in some fields at 
this time. Some fields have had all leaf tissue killed by a combination of damage 
from Septoria leaf blotch, powdery mildew, and leaf rust. If the leaves are 
killed while the kernels are still in the late milk stage, reduction in test 
weight and possibly in kernel size can be expected. Benhur is apparently resistant 
to the races of the rust found on the other varieties. Very little stem rust has 
been observed. 



WEEDS 



Field Crop Weeds 



It is too late now for Atrazine and oil applications. Most weeds are too large 
for good control, and late applications could result in Atrazine residue problems 
in the soil next spring. 

If you apply Treflan now for late-planted soybeans, there may be some chance of 
injury to fall-seeded grain from such a late application. 

Kith the cool wet weather of late May and other factors, we perhaps have had more 
than the usual amount of crop injury from herbicides this year. For aid in 
recognizing herbicide injury symptoms, refer to pages 51-54 of the 1966 Custom 
Spray Operators' Training School Manual; the February, 1967, issue of Crops and 
Soils Magazine ; or the July, 1968, issue of Successful Farming . 

Lawn Weeds 

One of the best ways to combat weeds in a lawn is to maintain a dense stand of 
grass. Heavy rains in much of Illinois have helped, in many instances, to cause 
a need for additional fertilizer, especially if the lawn is to be kept looking 
its best. 

Summer fertilization of the grass should be done with care. Follow the recommenda- 
tions for summer fertilization on the fertilizer bag. If directions are not on 
the bag, then directions for summer lawn fertilization and ways to prevent fertil- 
izer burn can be found in Circular 982, Keeping a Lawn, available from your county 
Extension adviser in agriculture. 

Crabgrass in lawns is becoming noticeable in much of Illinois. If you failed to 
get a preemergent herbicide on early, you might want to treat with one of the 
summer crabgrass control materials such as DSMA or AMA. Two or perhaps three 
applications of these materials are usually needed to achieve satisfactory con- 
trol. Often materials of 2,4-D type for control of broadleaved weeds are included 
with the crabgrass materials to give a broader spectrum of weed control. 

SPECIAL NOTE: 



Field days, featuring agronomy research programs, will be conducted at research 
centers throughout Illinois this summer. Representatives from the U. of I. will 
be present to discuss research programs on these fields . 

TIME FIELD 



DATE 

June 26 
June 27 
July 25 
Aug. 16 
Aug. 19 
Aug . 26 
Aug. 27 
Sept. 4 



TIME 

10:00 a.m. 

6:30 p.m. 

1:00 p.m. 

10:00 a.m. 

4:30 p.m. 

6:00 p.m. 

4:30 p.m. 

9:00 a.m. 



FIELD 

*DeKalbI/ 

*Carlinville 
*Carbondale_/ 

*Dixon Springs^.' 

Kewaneei/ 

Aledo 

Hartsburg—/ . 
* Browns town—' 



DATE 



1/ 



Sept. 


4 


6:00 p.m. 


Carthage 


Sept. 


5 


1:00 p.m. 


*Carlinville 


Sept . 


5 


1:00 p.m. 


Toledo 


Sept. 


6 


1:00 p.m. 


Oblong 


Sept. 


9 


1:00 p.m. 


*Newton 


Sept. 


L2 


8:00 a.m. 


*Urbana 


Sept. 


K> 


1:00 p.m. 


Dixon 


Sept. 


17 


1:00 p.m. 


Elwood 



T7 Food will be available. 

2/ Sponsored jointly by Southern Illinois University and the University of Illi- 
nois. All other meetings are sponsored by the University of Illinois except 
as noted. 

* Includes weed control research. 



SPECIAL NOTE TO EXTENSION ADVISERS 

Several have asked about methods of counting corn rootworm larvae. One method is 
to spread a piece of canvas on the ground, dig up a corn plant along with the 
soil in a 6 -inch square about 4 to 6 inches deep, and examine the soil carefully 
by sifting it through your hands several times. Then tear up and split the roots, 
also looking at the debris which has fallen off the roots. 

A second method resembles the first. Examine the soil, but cut off the roots and 
place them in a plastic bag. Look for worms that will leave the roots at 24-, 
48-, and possibly 72-hour intervals. 

A third system is to examine the soil in the field and save the roots. Place 
them on hardware cloth over a bucket, having first placed a piece of moist paper 
in the bottom of the bucket. Keep this moist and examine for worms at the end of 
48 hours. 

A fourth, the flotation method, is to mix a pound of salt per gallon of water. 
Place this in a bucket and put the dirt and roots still attached to the base of 
the plant in this salt solution. Any salt will do- -it does not have to be table- 
grade. Swish the roots and soil around several times. The rootworms will soon 
float to the top with the debris and foam. Sometimes this is an excellent method 
and \\'orks perfectly. At other times, the worms get mixed in with the debris which 
must be examined carefully several times. After the count is made, the salt water 
could be strained into another bucket and reused at least a few times. One problem 
is disposal of this concentrated salt solution. Do not dump it in the field. 

Interpretation? If the worms are still very small, and hatches just starting, 
and you find 4 or 5 per plant, make a basal application. Later when the worms 
are larger and hatch has progressed, 10 to 15 worms are needed to necessitate a 
basal treatment. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Cereal Leaf Beetle: T.J. Lanier, USDA, Plant Pest Control. 

Bees: E.R. Jaycox, Department of Horticulture. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy; J.D. Butler, Department of 
Horticulture. 

Ag Communications : Del Dahl . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 




INSECT 

SURVEY 

BULLETIN 



3 m\ 



v *ttw%. 




tate 



County 



Local Groups 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Aarjcultu^ 5fORfl[e rating 

JUL 3 1968 



FOR IMMEDIATE RELEASE 



UNiVtRilY OF ILLINOIS 
June 28, 1968 



ILLINOIS INSECT. DISEASE. AND WEED SURV EY BULLETIN NO. 16 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial ve g e table*uj£XG^tgd) , along with 
suggested, abbreviated control measures. Each individual snomW MJM his own 
fields to determine local conditions. in, „ . 

Jul. g 2 ms 

insects Htoatwir flr nutam 

Corn Insects 

Northern and western corn rootworm eggs continue to hatch, and in some fields of 
continuous corn in the northern half of the state an average of 30 larvae per 
plant are already present. Counts of 100 or more per plant will be common in 
problem fields within the next week or two. There is extreme variation in egg 
hatch and size of the worms from field to field. The worms scarify the surface 
and tunnel into the roots. They particularly like the tender, more succulent, 
newly-forming brace roots. By late July or August severely damaged plants will 
tip over. 

To find rootworm larvae, dig up a 6-inch-square area of soil about 6 inches deep 
around the corn plant. Examine the soil by breaking up the clods and sifting 
the soil through your fingers. Rework the soil several times. Then tear up and 
split the roots, watching the debris which falls for additional larvae. Another 
method of checking for rootworm larvae is the use of a salt solution. Mix a pound 
of crude salt or table salt in a gallon of water. Place the soil and roots into 
this solution and stir vigorously. The rootworm larvae will float to the top and 
with care can be sorted from the foam and debris and counted. Do not dump the 
salt solution in the field. 

If you suspect or know you have a rootworm problem (10 to 15 per plant or more 
justifies treatment) and you can still get a cultivator through the field, it 
still may not be too late (particularly in the northern section) to obtain some 
benefit. However, for best results the applications should have been made a week 
or two ago when eggs were just beginning to hatch. Further delay now in treat- 
ment will result in less effective control since damage is already occurring. 

We recommend 1 pound of actual diazinon, disulfoton (Di-Syston) , or phorate (Thimet) 
per acre as a basal treatment off the cultivator. The insecticide is directed at 
the base of the plant and the cultivator throws dirt over the chemical. 

First -generation European corn borer infestations are generally light in the prob- 
lem area of west -southwestern, west -central, and northwestern Illinois. In the 
most advanced corn between 5 and 40 percent of the plants were infested this week. 



-2- 

In the west -southwest section the optimum time for treatment is past as borers 
are already entering the stalk. In the west-central and northwest sections the 
time for treatment is this week (July 1) . 

To decide whether an insecticide can be profitably applied, measure the tassel 
ratio of the field and determine the percentage of the plants with recent feeding 
in the whorl leaves. To determine the tassel ratio, measure the height of the 
plants with leaves extended; split the stalk open and measure from the tip of the 
developing tassel to the base of the plant; divide the tassel height by the plant 
height; and multiply by 100. That figure is the tassel ratio. If the tassel 
ratio is at least 35 (preferably 40 to 45) and at least 75 percent of the plants 
show whorl feeding, treatment is justified. Use 1 pound of actual diazinon in 
granular form per acre or 1 1/2 pounds of carbaryl (Sevin) as granules. For 
spraying, use the same amount of actual insecticide per acre, and direct the spray 
to the upper third of the plant. Aerial applications should be granules, not 
sprays or dusts. Allow 10 days between treatment and ensiling of corn when ap- 
plying diazinon; carbaryl has no waiting period. Recent label approval has been 
granted for use of 7 1/2 to 10 pounds of 20 -percent carbaryl granules per acre . 
Our tests some years ago were with 5-percent granules, but we would anticipate 
similar control results. 

A report was recei\ r ed of black cutworms damaging waist-high corn in northern 
Illinois. The recent wet weather in many areas of the state makes conditions 
favorable for continued cutworm development. On tall corn the worms bore into 
the stalk just at or slightly below ground level and tunnel up or down in the 
stalk for a short distance. The leaves of infested plants first wilt and later 
turn brown. The plant will snap off readily if handled. On small corn the stalk 
is usually cut off and the plant pulled into the cutworm burrow. There is little 
that can be done to control the cutworm once corn is laid by. If you can still 
get a cultivator through the field, an application of 3 pounds of toxaphene, 2 to 
3 pounds of carbaryl (Sevin) , 2 pounds diazinon (as granules) , or 1 pound of 
trichlorfon (Dylox) per acre will control small worms. Direct the spray at the 
base of the plants , using at least 20 gallons of water per acre and cultivate 
immediately to cover the spray deposit. 

Common stalk borers are feeding in the whorls of some corn plants and the staixs 
of oats. These whitish-brown, striped worms with a purple band around their 
middle cause irregular holes to appear in unfolding corn leaves; in oats the heads 
turn white prematurely. Damage is most common along the edges of fields- - 
especially adjacent to fence rows, ditchbanks, roadsides, and grass waterways 
where there was a weed problem out in the field the previous year. Usually only 
a small percentage of the total plants are infested. Injury is of little con- 
sequence and by the time the stalk borers are found, it is too late for an in- 
secticide to be effective. You can lessen the problem for next year by keeping 
weeds under control in August and September. 

Black and yellow grass thrips (about 1/16 inch) are abundant in the whorl leaves 
of corn. The thrips rasp the leaf surfaces, leaving silvery patches. Plants are 
not usually seriously affected and will outgrow the damage. 

Corn leaf aphids are present in the whorl of corn plants in a few fields, partic- 
ularly in the west-southwestern section. Aphids were also observed on grasses in 
and bordering cornfields in the central section. These early aphid migrants are 
winged and will soon move to corn, giving rise to many young aphids. It is still 
too soon to determine how serious the problem will be in 1968. 



Soybean Insects 

Thistle or painted lady caterpillars are still present and feeding on soybeans. 
They web the leaves together in a nestlike manner and eat chunks out of the leaf 
margins in the same way that grasshoppers do. One worm will move a foot or two 
along the row as it feeds. The larva is covered with dark spines, and the body 
itself is velvety black with light green stripes running lengthwise. When full 
grown (1 1/2 inches) the larvae transform into silvery, pink, hard-shelled cocoons 
found attached to the undersides of the leaves. 



In general, infestations are not serious. Most fields have less than 10 percent 
feeding damage. Soybeans can withstand considerable defoliation (30-40 percent) 
before bloom without affecting yields greatly. Toxaphene and carbaryl (Sevin) 
have both provided good control of this insect. Do not feed soybeans as forage 
to livestock if treated with toxaphene. 

Homeowner Insect Problems 

Cottony maple scale eggs are hatching, and the young 
crawlers are moving to the leaves to feed. The eggs 
appear as cottony masses (like popcorn) on small twigs 
and branches. This scale is particularly injurious 
to soft maple but will attack a variety of trees and 
shrubs . 

Apply control measures within the next week or two to 
kill the young crawlers before they develop protective 
coverings . A malathion spray containing 2 teaspoons 
of the 50-57 percent liquid concentrate per gallon of 
water is effective. 

Bagworm hatch is now complete in northern Illinois, 
and larvae are feeding on evergreens and other trees 
and shrubs . Treatments should be made when the worms 
are young and easy to kill before severe damage is 
done. Carbaryl (Sevin), diazinon, or malathion are 
all effective. Malathion will provide fair control 
of mites that might be present. Follow label direc- 
tions and check plants that may be injured if sprayed 
with the insecticide you are using. 

, , , , , , . Cottony maple scale 

Striped and spotted cucumber beetles are attacking 

vine crops in the home garden. The beetles may kill 

small seedlings and seriously retard or kill older plants. Carbaryl (Sevin) or 

malathion will control these insects. Follow label directions for dosage and 

precautions. Make the application late in the day to avoid injury to bees. 

Mosquito populations continue high in many areas . This is fast becoming another 
record high year for these insects. To reduce the number of mosquitoes in your 
yard, follow these steps. (1) Eliminate standing water in such places as eaves, 
troughs, old tires, tin cans, children's toys, storm sewers, etc. (2) Apply a 
water-base spray containing 1-percent malathion (2 ounces of 50-57 percent liquid 
concentrate per gallon of water) to shrubbery and tall grass. Repeat the treat- 
ment every week or two if needed. (3) Keep the screens on doors and windows in 




good repair. (4) Hang plastic resin strips (2" x 10") containing 20-percent 
dichlorvos (DDVP)--one strip per 1,000 cubic feet of space, or about one per room. 
These strips will kill mosquitoes and flies for 4 to 6 weeks. Hang the strips 
out of the reach of children and away from fish bowls and food counters. Repeat 
treatments with 0.1 -percent pyrethrum space spray- -applied from a pressurized 
spray can- -can be used for quick knockdown in place of the dichlorvos resin strips. 
(5) When entering mosquito -infested areas, use a repellent. One of the most 
effective mosquito repellents is DEET (diethyltoluamide) . (6) For quick knock- 
down at cookouts, outdoor parties, or picnics, use either 0.1-percent pyrethrum 
or 0.5- to 1 -percent dichlorvos (DDVP) as an oil- or water-base space spray. 
Spray the mist lightly beneath tables and chairs and into the air for a few feet 
around the area. Repeat the treatment as needed. 

Ants, spiders, crickets, millipedes, sowbugs , roaches , and other crawling insects 
continue to enter homes. If you sprayed the foundation wall of your home in May, 
it may need another treatment now. Buy chlordane as a liquid concentrate and 
dilute it with water to the proper strength (1 pint of 45-percent chlordane liquid 
concentrate in 3 gallons of water gives a 2 -percent solution). Spray the founda- 
tion from the sill to the soil until the spray runs off. Also, spray 2 to 3 
inches of soil next to the foundation wall. Spray in cracks or expansion joints, 
along porches and around steps, and along the edge of sidewalks and driveways. 
In houses with crawl spaces, treat the inside of the foundation wall as well as 
the outside, and spray support pillars. The average house requires about 3 gal- 
lons of finished spray. Do not spray near wells or cisterns. Do not spray 
shrubbery or flowers because the oil may burn the foliage. Repeat the treatment 
again in late summer for protection in the fall. 

WEEDS 

Herbicide injury seems to be a little above normal this year. Injury to soybeans 
from atrazine carryover is being observed in some fields. Symptoms vary from a 
slight mottling of some leaves to necrotic brown sections in others. There are 
some completely dead plants. The severity depends on the amount of atrazine left 
in the soil. Injury is most evident on field ends where sprayers were filled, 
where sprayers were left on when turning, or where there was overlapping. Where 
correct rates were carefully applied, injury is usually not severe. And slight 
injury to soybeans early in the season may not be reflected in final yields. In- 
jury may look worse than it actually is. This indicates the need for future rate 
adjustments and careful application. 

There are several factors that may have contributed to herbicide carryover in some 
fields this year. Temperatures in 1967 were below normal. Some areas were 
relatively dry last summer or early this spring. Both chemical and biological 
degradation of herbicides proceed faster with warm moist conditions. 

In some fields atrazine postemergence was not applied until mid-June of 1967 and 
soybeans were planted in early May of 1968. This gave a relatively short period 
of time for herbicide decomposition as compared to preplant or preemergence applica- 
tions in April or early May of 1967 with soybean plantings in June of 1968. Some 
research suggests that when atrazine is incorporated into the soil immediately, 
loss of the herbicide from the soil surface may be reduced and residue in the soil 
may be increased. 



Where tillage is minimized and the herbicide is not sufficiently diluted by mixing 
with more soil, there is more chance of carryover injury. Some increase in carry- 
over may be associated with broadcast applications. Make careful observations in 
your fields this year and try to select rates for next year that will be sufficient 
for weed control without residue problems. Consider combining herbicides and 
rotating herbicides to decrease residue problems. The surest way to avoid herbi- 
cide injury is not to use herbicides. But in spite of the occasional problems, 
the benefits from herbicides usually far outweigh any disadvantages. 

Injury to fall -seeded wheat where Tref Ian had been used on soybeans has not been 
serious in the past, but it may pay to try to avoid planting wheat this fall where 
Tref Ian was applied unusually late this spring. 

Help make America beautiful . Give a boy a haircut, and spray weeds in fencerows. 
One quart of 2,4-D and 5 pounds of Dowpon in 50 gallons of water will treat 
2 miles of fencerow 4 feet wide. Some custom applicators should be able to pick 
up extra business and satisfied customers with a fencerow spray program. Vary 
the herbicides and rates to fit the situation. And use care to avoid injury to 
adjacent crops. 

DUCKWEED CONTROL 

Frequently ponds become infested with duckweed, Lemna minor. This species is 
difficult to control because the mature seed -producing plant is small, and a large 
number of plants are involved. Applications of Diquat or disodium aquathol, 1 cup 
of herbicide diluted to 4 gallons, applied directly to the duckweed as a fine 
spray will reduce the duckweed population. Applications about every two weeks 
will be required to keep the duckweed under control. We have not been able to 
eliminate duckweed from a body of water, but by the repeated applications have 
kept the water surface relatively free of duckweed. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Weeds: Ellery Knake, Department of Agronomy; Robert Hiltibran, Illinois Natural 
History Survey. 

Ag Communications : Del Dahl . 

The information for this report was gathered by these people, staff members, 
county extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



l~ ^>v / 




ite 



/ County / Local Groups 



INSECT 

SURVEY 

BULLETIN 



-**"'%%, 




'%0I\* 



# 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



July 5, 1968 



ILLINOIS INSECT. DISEASE, AND WEED SURVEY BULLETIN NO. 17 
This series of weekly bulletins provides a generalJ^Dffhoe^ ±h& insect, plant dis- 



ease, and weed situation (fruit and aommeroial vegetables'"e'xc T ep'Q&d) , along with 
suggested, abbreviated control measures. Each indiyddus^lfpsl^uld check his own 

ummtu ar nam 



fields to determine local conditions. 



INSECTS 



THE LIBRARY OF THE 
JUL S 1968 



Corn Insects 



IINSVERSIV OF ILLINOIS 



Corn rootworm development is progressing rapidly. This week occasional, early- 
emerging adults were observed. In addition, between 2 and 3 percent of the root- 
worm population is now in the resting or pupal stage, and will soon change into 
adults. Apparently, rootworm development is earlier in western than in eastern 
Illinois; but, in general, it is now too late to make a basal or cultivator appli- 
cation of an insecticide in most fields. In most instances, corn-plants breakage 
and root pruning would be too great to justify this basal application. Also, in 
most fields, the worms are now big enough to be difficult to kill by late insecti- 
cide applications. 

Billbugs are damaging late -planted corn; in a few of these problem fields, damage 
is severe. Billbugs are gray, brown, or black snout beetles (1/5- to 3/4 -inch) 
that drill holes in the stalk below ground level, usually at or just above the 
main roots. When the leaves emerge, they have a series of holes in them. The 
adult snout beetles stay hidden in the soil and under clods during the day, but 
often move readily from plant to plant at night. Soil treatments with aldrin and 
heptachlor have never been highly effective against billbugs. 

If damage is severe and treatment indicated, apply 1-1/2 pounds of actual carbaryl 
(Sevin) as a band spray over the row. 

Corn flea beetles continue to damage occasional, late-planted cornfields that are 
bordered by grassy areas. These small black beetles (that jump readily when dis- 
turbed) leave white scratch marks on the leaves. Once corn reaches 10 to 12 inches 
in height, it can usually grow away from flea-beetle injury. 

If damage is severe and plants are being killed, apply 3/4 pound of carbaryl 
(Sevin) - -preferred on dairy farms--or 1-1/2 pounds of toxaphene per acre as a band 
spray over the row. 

The first European corn borer larvae are maturing rapidly, and many of them have 
already entered the stalk. Development appears to be slightly earlier than normal. 
Once they have bored into the stalk, insecticides no longer control them. It is 



-2- 

too late to effectively control these borers now. There were only occasional 
fields of early planted corn with sufficient infestations (75 percent or more of 
the plants with borer feeding) to justify treatment. Most advanced fields of 
corn have a light number of corn borers. With good survival of this first genera- 
tion, we could still experience second -generation corn borer problems in some 
late-maturing cornfields. 

Black cutworms might possibly still appear in cornfields. If a late generation 
occurs, damage could be extremely severe. Watch fields for an occasional dead or 
dying plant. Examine such plants to see how large an area has been gouged out of 
the stalk below the soil level. Examine other areas of the field to see if worms 
are present, or if this is just an occasional worm doing damage. 

Common stalk borers can still be found in some cornfields. These are whitish- 
brown, striped worms with a purple band around the middle. They feed in the whorl. 
Emerging leaves have irregular holes in them. Damage is usually most common along 
the edge of the fields. The damage is not thought to be serious; by the time 
injury is noticed, it is too late to apply an insecticide. However, controlling 
the weeds along the edge of the field and out in the field in August and September 
will decrease the problem for next year. 

Fall armyworms may soon appear in late-planted cornfields. Areas in a field will 
have numerous plants with severely chewed leaves. Dark brown, smooth- skinned 
worms will be found feeding in the whorls of plants. This will appear in "patches" 
in the field, because the moths deposit a cluster of 50 to 100 eggs on one plant. 
The worms move to adjacent plants as they hatch, infesting several plants in a 
row. Control is usually not recommended since the plants usually grow away from 
the damage. 

In cases of severe damage, try granules of either carbaryl (Sevin) or toxaphene 
at 1-1/2 pounds of actual chemical per acre. Do not feed toxaphene -treated corn 
as forage to dairy cattle. Do not feed toxaphene -treated corn as forage or stover 
to livestock fattening for slaughter within 28 days of slaughter. 

Soybean Insects 

Thrips , commonly found last week in the whorl leaves of corn, are increasing in 
number on soybeans in some areas. These small, yellow-to-black thrips (about 
1/16-inch long) rasp the surface of the leaves, giving them a "silvery" appearance. 
Plants will usually outgrow the damage, and rain helps. 

Small, green, gnat-like leafhoppers are also numerous on soybeans. But as yet, 
damage is of minor importance and no control is needed. 

Homeowner Insect Problems 

"Cottony" maple scale eggs are hatching, and the young crawlers are moving to the 
leaves to feed. The eggs appear as cottony masses (like popcorn) on the small 
twigs and branches. Soft maple is the primary variety attacked, but this scale 
also feeds on other trees and shrubs. If control is needed, apply within the next 
two weeks. Use 2 teaspoons of 50- to 57-percent malathion liquid concentrate per 
gallon of water. 



-3- 

Eim leaf beetle larvae are feeding on elm foliage , especially Chinese elms. The 
dirty-yellow to black worms feed on the underside of leaves, skeletonizing them. 
Spraying the foliage with carbaryl (Sevin) at the rate of 2 pounds of 50 -percent 
wettable powder is effective. Another treatment about the first of August (this 
timing is suggested for central Illinois) may be needed for the second generation. 

Aphids are building up on roses, as well as on other flowers, shrubs, and trees. 
Spraying with malathion or diazinon will give effective control. A repeat applica- 
tion may be needed later, if populations begin build up again. Follow the direc- 
tions and precautions listed on the label. 

PLANT DISEASES 

Corn 

Corn smut is unusually prevalent on the stalks and leaves of corn this year. The 
large galls low on the stalk can kill the plants. These galls also cause extreme 
deformation that may result in unproductive plants . Galls on the leaves are not 
particularly harmful. Ears and tassels can be destroyed. Evidently, the weather 
conditions have been ideal for infection by the smut fungus . There is no chemical 
control for this disease. 

Soybeans 

Rhizoctonia and phytophthora fungi are now killing seedling soybean plants. 
Phytophthora damage occurs primarily in low spots in the field. Rhizoctonia damage 
occurs on both high and low ground. If phytophthora is a problem, the grower should 
use resistant varieties in the future. 

Septoria brown spot is beginning to appear in some soybean fields. This fungus 
disease occurs on the lower leaves first, moving upward later in the season. The 
leaflets turn yellow and have scattered chocolate -brown spots on them. The spots 
do not fall out. 

Wheat 

Glume blotch is a problem in a number of wheat fields. The disease is recognized 
by light tan -to -brown lesions on the upper half of the glumes and lemmas of the 
spikelets. Small dark pycnidia (spore cases) occur on the diseased areas and are 
diagnostic. Kernels in the diseased heads tend to be somewhat smaller and lighter 
than those in healthy heads . 

WEEDS 

Just at press time, a flurry of reports started to come in concerning onion-leafing 
on corn, associated primarily with 2,4-D application. We'll have more information 
on this in next week's BULLETIN. 

Onion- leafing , malformation in brace roots, brittleness, and elbowing of the stalks 
are typical symptoms of 2,4-D injury to corn. We have some every year. Overdosing 
is one cause. If you direct 2,4-D toward the row, be sure to adjust your rates so 
you don't apply more than the recommended rate on the area actually treated. Also, 
injury may be more likely if you spray during hot, humid weather. Some hybrids 
are more sensitive than others to 2,4-D. It may pay to check with your seedsman 
before you spray. 



-4- 

In spite of occasional injury, 2,4-D is still one of the most effective and least 
costly treatments for controlling many broadleaved weeds in corn. There will 
probably be 3 to 4 million acres treated in Illinois again this year. 

Don't wait until corn is tasseling or silking to apply 2,4-D. Apply it early, 
while weeds are small and are the easiest to kill. 

Banvel-D can give greater control of smartweeds in corn than 2,4-D. But if you 
plan to use Banvel-D, be fully aware of the possibility of injury to nearby soy- 
bean fields. See the 1 968 Weed Control Guide or the Agronomy Handbook for more 
details. If you used atrazine earlier, you very likely do not have a serious smart- 
weed problem now. Smartweeds are quite sensitive to atrazine applied preemergence 
or as a very early postemergence treatment. 

2,4-DB may help control a serious infestation of cockleburs in soybeans. It can 
also help control annual morningglory and giant ragweed. But again, be aware of 
the risk of soybean injur/. Refer to the 1968 Weed Control Guide for details. 

In addition to the previous clearance (for broadcasting 2,4-DB from 10 days pre- 
bloom to midbloom) , there is a new clearance for application as a directed spray, 
when soybeans are 8 to 12 inches tall and cockleburs are 3 inches tall. 

Panicum and crabgrass may be late-season grass problems in cornfields, especially 
where corn stands are thin or in inbred seed fields where plants are short and 
there is little shade. With these late grasses, only the seeds near the surface 
germinate. In some fields, these grasses can be controlled with timely cultivation. 

You may find panicum or crabgrass developing in fields that were treated earlier 
with atrazine. Ramrod applied shortly before or immediately after crabgrass and 
panicum germinate might provide satisfactory control, but timing is critical. 
Directed postemergence applications of Lorox or Dowpon are other possible con- 
trols, but these should be applied when the grasses are small. Be sure to keep 
Lorox and Dowpon off the corn leaves. 

If you find a serious infestation of crabgrass or panicum this year, consider 
planting soybeans and using Treflan next spring. 

Leaflets three --let it be . It may be poison ivy. If you need wall charts to help 
the kids at summer camp"Tdentify poison ivy ask for Circular 850, Controlling 
Poison Ivy, available from your Extension adviser in agriculture; or write to the 
Information Office, College of Agriculture, University of Illinois, Urbana, Illinois 
61801. 

Amitrole or Amitrole-T is effective for controlling poison ivy. Now is a good time 
to spray. See Circular 850 for details. A slide set on "Identification and Con- 
trol of Poison Ivy" is available for loan from county Extension visual libraries. 
Ask your Extension adviser. 

NOT FOR PUBLI^TION^SPECIATNOTE TO RADIO AND TELEVISION STATIONS 

The 1:45 tape recording from our automatic telephone answering service of the 
weekly insect report has been expanded for your convenience. 



The report for the northern half of Illinois is available between 5 p.m. Thursday 
and 11 a.m. Friday of each week. 

The report for the southern half of Illinois is available between 11:05 a.m. Friday 
and 2 p.m. Saturday . 

The number to call is (217) 333-2614. Have your recorder running when you call. 
The report summarizes the week's insect activity and forecasts next week's insect 
problems. You should contact your Extension adviser in agriculture for the local 
angle. 

For more information or in case of difficulty, call Mr. Cliff Scherer in the Agri- 
cultural Communications Office, 330 Mumford Hall, University of Illinois, Urbana, 
Illinois: (217) 333-4783. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report \vas prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy. 

Ag Communications : Del Dahl . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



£A^^ 




INSECT 

SURVEY 

BULLETIN 



*%W%, 







# 

<W^ 



ate / County 



Local Groups 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



July 12, 1968 



ILLINOIS INSECT, DISEASE, AND WEED SURVEY BULLETIN NO. 18 

This series of weekly bulletins provides a general look at the insect, plant 
disease, and weed situation (fruit and commercial vegetables excepted) , along 
with suggested, abbreviated control measures. Each ■,J-^& l &3v$' should check his 



own fields to determine local conditions. 



INSECTS 



Corn Insects 



JUL 



r> r) W* 



ft.U»»* 



" jut 17 1968 



First-generation European corn borers have begun to pupate in the southern half 
of Illinois. Pupation is almost complete in the southernmost counties; moth 
emergence has begun. Watch for whorl damage to late corn by the last week of 
July. 

In south-central Illinois, pupation ranges from 10 to 40 percent in field corn; 
moth emergence will begin in late July, In early August, watch for feeding on 
corn that is in the late-whorl to early-silk stage. 

Second-generation infestations in late field corn can be handled in the same way 
as the first -generation problem. If 75 percent of the plants have whorl-leaf 
feeding, apply carbaryl or diazinon granules. If the corn has tasselled, look 
for egg masses. If the average is about 1 per plant, apply an insecticide when 
a few eggs have begun to hatch. 

A survey this week of the most mature fields in the area between highways 40 and 
50 revealed that first-generation borer populations ranged from 25 to 90 per 100 
plants- -100 mature borers per 100 plants represents a 3-percent decrease in yield. 
It is too late to control this first generation; with these low numbers, it might 
not have been profitable anyway. 

Southwestern corn borer is present in several southern Illinois counties. Poten- 
tially, it is a more serious corn pest than the European corn borer. Fortunately, 
it does not yet overwinter too successfully in our climate, because its origin 
was Mexico or Arizona. However, it appears to be slowly adapting to Midwestern 
conditions. 

A random field survey in the four southernmost counties revealed an average of 
10 to 30 first-generation southwestern corn borers per 1,000 stalks of corn. 
This is probably the highest infestation ever in Illinois. 



-2- 

These first-generation borers have begun to pupate. Some moth emergence is ex- 
pected within the next week, but peak emergence should not occur before the week 
of July 22, or perhaps the week of July 29. Egg- laying will begin within 2 days 
following emergence. Only late fields of corn should be affected. 

To determine the need for insecticide treatment, examine the whorls of late- 
planted corn for signs of leaf -feeding by European and southwestern corn borers. 
Both insects feed in the whorl. As the leaves emerge, they show regular patterns 
of circular or elongated holes across the leaves. Also, there is some stripping 
of the plant tissue, appearing as white areas where the green tissue was eaten. 

If you find 60 percent or more of the whorls with this feeding, it is time to 
treat. If only southwestern borers are present, as little as 10 to 25 percent 
of whorl feeding may mean economic damage. One to three insecticide applications 
may be needed to control an infestation of southwestern corn borers alone or a 
mixture of both the southwestern and European corn borers. Only one application- - 
at the most two- -would be needed to control European corn borers alone. 

Egg counts are another way of determining the need for southwestern corn borer 
control. If you find 25 egg masses per 100 plants, treatment may be profitable. 

We have no Illinois information on chemical effectiveness, since treatments have 
never been made before. Entomologists in the states to the south and west of Il- 
linois recommend 2 to 3 applications of insecticides at intervals of 7 to 10 days. 
Granules are preferred over sprays. Endrin at 0.3 to 0.4 pound per acre per ap- 
plication is usually recommended. Also, 2 pounds of carbaryl (Sevin) or 1 to 2 
pounds of diazinon are suggested. Although endrin may be the most effective, we 
do not encourage its use in the area of Illinois most heavily infested with the 
southwestern corn borer, because many such fields are near wildlife and waterfowl 
refuges and fish-bearing waters. 

Do not use ensilage, stover, or fodder from endrin- treated corn. If you use diazi- 
non, allow 10 days to elapse before using the ensilage, stover, or fodder. No 
waiting period is required for carbaryl. 

Southern corn rootworm larvae, pupae, and adults (spotted cucumber beetles) are 
present in some cornfields in the southern half of Illinois. The larvae eat the 
roots. In some late cornfields, they have tunnelled up into the stalks, killing 
the heart of the plant. The beetles feed in the leaves and silks of the corn. 
They will deposit eggs in the soil for another generation or two yet this year. 

Northern and western corn rootworms are developing as anticipated. Pupation 
has begun in northern Illinois, but eggs are still hatching and very tiny worms 
can be found. This situation may exist for another two weeks. Damage to roots 
is now evident in many fields; it will become progressively worse during July. 

In northern Illinois, only late cornfields can profit from basal treatments. In 
case you find extremely high infestations in earlier fields, you may, in despera- 
tion, want to try a broadcast application of diazinon, phorate (Thimet) or di- 
sulfoton granules without cultivation. However, the prospects for effective con- 
trol by this method are not good, unless timely rains should occur. 



-3- 

The number of corn leaf aphids is increasing this week. Some fields in the south- 
southwestern part of the state have a few plants that are heavily infested. Both 
winged and wingless aphids can be found on grasses and in the whorls of corn 
plants. These insects suck the juices from the plant. Such damage usually oc- 
curs just prior to and during tasseling. Check the whorls of corn plants for 
these insects during the two-week period prior to tasseling. 

Early treatment is best. When the corn is in the late-whorl stage and 50 percent 
or more of the plants have aphids (with a few plants heavily infested) , and if 
the corn is under stress, treat immediately. Treatment is also justified in corn 
in the early tassel- to-pollinating stage, if 15 percent or more of the plants are 
heavily loaded with aphids. 

Spray treatments by ground or air with 1 pound of malathion or diazinon per acre 
will provide control. When using malathion, allow 5 days between treatment and 
harvest for grain, ensilage, or stover. There is no waiting period between treat- 
ment and harvest for grain for diazinon, but allow 10 days for ensilage or stover. 
If corn is still in the late-whorl stage, seed producers may prefer to use 1 pound 
per acre of either diazinon or phorate (Thimet) as granules. To avoid potential 
hazards to detasselers, use phorate only on male- sterile corn. 

Common stalk borers in border rows of corn are still causing concern, but should 
soon disappear. Keep fence rows, ditch banks, grass waterways, and similar areas 
mowed during August to help prevent infestations next year. This is where the 
moths deposit their eggs. 

Black cutworms were found this week in a cornfield in south-central Illinois. 
About 10 percent of plants had been hollowed out below the ground level, and 
these plants were dead. It is too late for control when this has happened. 

True armyworms have been observed in grassy cornfields in the northern half of 
Illinois. Watch such fields closely; the worms feed first on the grass and then 
move on to the corn plant. For infestations, apply carbaryl (Sevin) or toxaphene. 

There is no waiting period between application and harvest of the crop for grain 
or ensilage if you use carbaryl. If you apply toxaphene, there is no restriction 
on use of grain, but do not feed treated forage to dairy animals. Do not feed 
ensilage, fodder, or stover to livestock within 28 days of slaughter. 

Soybean Insects 

Bean leaf beetles are now present in southern Illinois, but not in damaging numbers. 

Very small, green cloverworms are present in soybeans in central and northern Illi- 
nois. These pale, green worms with white stripes are the ones that feed heavily on 
soybeans, usually in August. If the plants are jarred, they fall to the ground. 
When touched, they twist their body rapidly- -almost as if they were a spring. The 
severity of this problem remains to be seen, but a fly parasite lays tiny, white 
globular eggs on the backs of these worms. When present in sufficient numbers, 
they aid in control. 



Livestock Insects 

The number of face flies is now increasing, on both dairy and beef cattle. We do 
not know all the factors involved in this growth pattern. With the population 
now on the increase in southern, central, and western Illinois, it would be well 
to check on them weekly. 

If control becomes necessary, apply 2 percent Ciodrin at 1 to 2 ounces per animal 
2 to 6 tunes per week, either by an automatic cattle sprayer or with a hand sprayer. 
For beef animals on pasture, you may want to try 5-percent toxaphene in oil. To do 
this, saturate a cloth, canvas, or burlap head or back oiler at least weekly. 

Do not treat cattle under 4 months of age with toxaphene and do not apply within 
28 days of slaughter. Do not contaminate feed, water, milk, or milking utensils 
with Ciodrin. 

HOMEOWNER INSECT PROBLEMS 



Picnic beetles are especially numerous at the present time. These black beetles 
with four yellow spots are attracted to food odors and decaying or overripe fruit 
and vegetables. They are commonly found around garbage cans and on window screens, 

For control in home yards , harvest fruits and vegetables before they become over- 
ripe. Dispose of any spoiled produce. To kill the adult beetles, spray with mala- 
thion, diazinon, or carbaryl (Sevin) on and around garbage cans. Spraying shrub- 
bery and tall grass with the same insecticides before a cookout will greatly 
reduce the number of these beetles. Follow directions on the label; check plants 
that may be injured if sprayed with the insecticide you are using. Either 0.1- 
percent pyrethrin or 0.5-percent dichlorvos (DDVP) in pressurized spray cans will 
give a quick knockdown of beetles that suddenly move into an area. 

Tomato h ornworms as well as fruitworms (corn earworm) are common in tomato patches 
in the southern half of the state. Spray with carbaryl (Sevin), using 2 table- 
spoons of 50-percent wettable powder per gallon of water. Repeat if necessary 
each week. There is no time limit between treatment and harvest. 

Variegated cutworms will soon be common pests of several vegetable crops and 
flowers with heavy foliage in home gardens. Carbaryl will control them. 

PLANT DISEASES 

Corn 

A secondary effect of the widespread 2.4-D iniury to corn has been the increase 
of corn smut infection on the injured plants. Many smut galls are prevalent near 
the whorl at the base of the "onion" leaf. Most of the smut galls are on leaves 
and sheaths and will do little damage. Some galls involve the developing stalk 
and will be damaging. The increase in smut, following 2,4-D damage is on hybrids 
that are normally susceptible to smut. 

Soybi ins 

Bacterial blight is appearing in some fields at this time. It is recognized by 
the angular leaf spots, usually surrounded by a narrow zone of yellow leaf tissue. 
The dead spots tend to fall out of the leaf. Severely infected leaves may have a 
ragged appearance. 






Homeowner Plant-Disease Problems 

Early blight on tomatoes is now showing up in home gardens. Look for roundish- 
to- angular dark brown spots, with angular rings or ridges within them. Affected 
leaves turn yellow or brown and drop early, starting at the base of the plant. 
Exposed fruit later sunscald. The same fungus may cause dark brown- to-black, 
sunken, leathery spots on the "shoulders" of the fruit near the stem end. 

Control earl>- blight by applying maneb (mostly sold as Manzate, Manzate D, Ortho 
maneb, Di thane M-22) or Dithane M-45 as sprays at 7- to 10-day intervals. If the 
weather is rainy, shorten the interval to 5 days; if it is dry and hot, lengthen 
the interval, up to 14 days. Thorough coverage of foliage and fruit is essential. 
Multipurpose vegetable dusts and sprays usually have maneb as an active ingredient, 

Blossom- end rot on tomatoes can be found now wherever fruits are at least half- 
grown. The bottom or blossom end of the fruit becomes dark brown- to-black, and 
is sunken and leathery. Up to one-half of the fruit may be involved. 

The control for this disease is to water during dry periods. Where feasible, 
maintain a uniform soil -moisture supply and promote steady growth. Mulch or 
cultivate in a shallow fashion during dry periods, and fertilize adequately- - 
based on a soil test. Avoid overfertilizing with nitrogen and potassium. Four 
weekly applications of calcium nitrate, starting when the first fruits are the 
size of golf balls, may help. Use 1/2 to 3/4 of an ounce per gallon of water. 
Calcium nitrate may be added to the maneb used to control early blight. 

Cat face on tomatoes is another disease now prevalent in home gardens. The blos- 
som end of the fruit is extremely malformed and scarred with irregular, swollen 
protuberances and bands of scar tissue. The control is to grow locally adapted 
varieties and use the same treatment recommended for blossom-end rot. Cat face 
may be caused by drought or by high (95° F. or above) or low (55° F. or below) 
temperatures that reduce pollination on contact with a hormone-type herbicide, 
such as 2,4-D. The disease is due to poor pollination. 

Early blight on potatoes can be found now and will be increasing with summer 
showers and heavy- dews. The symptoms and control are the same as those for 
tomatoes . 

Blackleg on potatoes is common in Illinois following heavy rains and cold weather 
in heavy, poorly drained soils. Affected plants are stunted, upright, and wilt- 
ing, with curled upper leaves. The stem base may be an oily green, but it soon 
becomes dark brown- to-blackish, slimy, and rotted. The seed piece is often de- 
cayed, and such plants are easily pulled up. Blackleg commonly follows seed- 
corn maggots, wireworms, white grubs, borers, hail, or other injuries. The only 
control procedure is to plant the best blue- tag seed available and to control 
insects . 



WEEDS 



Corn 



This year, 2,4-D injury- to corn seems to be more severe than ever before in the 
history of 2,4-D use in Illinois. 



-6- 

The major sign of injury during the past week has been " onion- leafing ." Although 
the total number of fields actually affected may still be relatively low, some 
fields have shown rather severe, tight rolling of the leaves. 

This rolling has occurred in many areas of the state on many different hybrids 
and apparently with many different 2,4-D formulations. Although some injury has 
shown up after both early and late spraying, most of the injury seems to have oc- 
curred where corn was sprayed early, when it was only a few inches tall. 

Our best guess is that with the cool, moist stress conditions present during the 
last part of May, the 2,4-D affected the plants when most of the leaves were in 
the very early stages of formation- -surrounding the growing point and hardly 
recognizable as leaves. Then, with the subsequent moist and hot weather and 
pattern of extremely rapid growth, these early effects later became visible as 
the onion- leafing. 

An occasional tendency toward onion- leafing has been reported this year even in 
fields not sprayed with 2,4-D. This is most likely related to the very rapid 
growing conditions, possibly to certain genetic lines of corn. 

Usually in previous years, only a very small percentage of the plants in a field 
where extensive onion- leafing has appeared have been seriously affected. Leaves 
have usually unrolled soon enough for tassels to emerge. Pollination was nearly 
normal, and there was little effect on ears. This year, however, where some of 
the leaves seem to be very tightly rolled, there may be a greater- than-usual ef- 
fect on tassel emergence. It's difficult to predict what the result may be on 
ears; but with a smaller leaf area exposed for normal photosynthesis, ear devel- 
opment may be affected. 

There seems to be an increase in smut in some fields. Where the corn was brittle, 
cracking opened the way for more smut. The seriousness of the situation will have 
to be assessed in individual fields, using common sense and good judgment. Hope- 
fully, some fields may outgrow the injury fairly well. 

This problem would tend to make one cautious about applying 2,4-D during the next 
few weeks. However, the symptoms we see now do not necessarily mean that severe 
problems will develop with later spraying. 

Do not spray injured fields a second time with 2,4-D. Avoid spraying on hot, 
humid days. Be sure the correct rates are carefully applied. 

There is little that can be done now about the injured fields, except to hope 
that a high percentage of the plants will outgrow most of the injury. 

Pond Weeds 

Chara vulgaris , commonly known as mushgrass, becomes abundant in many bodies of 
water in Illinois. At this time of year, other vegetative problems may have 
matured or responded to applications of herbicides. 

In general, chara resembles other aquatic vegetation. But since it is an algal 
species, it is not susceptible to commonly used herbicides, such as endothal or 
2,4-D. Stands of chara can be eliminated by applications of crystals of copper 
sulfate directly to it. This is the cheapest and most -effective method for con- 
trol. Chara has a pungent odor, and this can be imparted to the water and fish. 



NOT FOR PUBLICATION- -SPECIAL NOTE TO COUNTY EXTENSION ADVISERS 

Fly control at county fairs : We have modified the following portion of a Purdue 
Insect Newsletter on this subject to fit Illinois conditions: 

1. Fair officials will need to be sure that manure, garbage, refuse, and soft 
drink bottles are removed from the grounds every day. This is a must. 

2. Just before the Fair starts, spray livestock sheds and other buildings that 
may harbor flies with dimethoate (Cygon) , diazinon, or ronnel (Korlan) . A 
farm crop-sprayer, equipped with a lead of hose and a spray gun, can be used 
for this purpose. Most rotary pumps on these sprayers can be adjusted to 
operate at 250 to 300 pounds of pressure. 

If the water pressure is good, a spray gun that fits on the end of a hose 
will do a good job of applying the insecticide. 

Sprays can also be applied to refuse containers, garbage cans, etc. --before 
and during the Fair. A couple of boys with compressed-air sprayers can do 
this job. 

3. The clip-on foggers that attach to a gallon can of oil-base pyrethrins and/or 
DDVP fly spray will do a good job of killing adult flies in animal shelters. 
These fogs are best applied in the early morning when no people are around. 
Animals need not be removed, although horses may be frightened by the fog. 

4. Urge that food stands keep some pyrethrins and/or DDVP household pressurized 
spray cans on hand, to kill adult flies. These sprays should be used at night 
after the stands close. The local health department should insure that all 
stands maintain the required standards of cleanliness. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Plant Diseases: M.P. Britton and M.C. Shurtleff , Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy, and Robert Hiltibran, Illinois 
Natural History Survey. 

Ag Communications: Del Dahl . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 




INSECT 

SURVEY 

BULLETIN 



,*»'«% 




% 



,# 



County 



Local Groups 



FOR IMMEDIATE RELEASE 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 

July 19, 1968 



ILLINOIS INSECT, DISEASE, AND WEED SURVEY BULLETIN NO. 19 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



i 



INSECTS 






I 



Corn Insects 



I 



Corn leaf aphids have increased rapidly in fields in many areas, especially across 
the central part of the state. In many fields, populations have increased to the 
point where more than half the plants in a field are infested with at least a 
small colony; the infestation in some plants is moderate to heavy. A few fields 
have an infestation as high as 100 percent. 

Corn leaf aphid infestations usually begin while the plant is 
in the whorl stage probably, two to three weeks ahead of full 
tassel, reaching a maximum during peak pollen shed. Infesta- 
tions decline rapidly after that. The time to decide about 
treatment is now . Fields where the plants are now in full 
tassel will most likely escape damage; fields with more than 
half the tassels showing may escape injury, while those with 
a few or no tassels showing are most likely to suffer damage 
and should be examined critically until after pollen shed. 

To examine a field for aphids, (1) pull 25 \\'horls in four places in a field, 
(2) unroll the leaves, and (5) determine the percent of infested plants and degree 
of damage. If the next two weeks are hot and dry, the population of aphids is 
most likely to increase greatly, decreasing with cool, rainy weather. We have 
observed very few predators. The black beetles with the four yellow spots, com- 
monly seen in the whorl , are picnic beetles . They are not predators and do not 
damage plants. 

Treatment is justified on late-whorl-stage corn (a few tassels showing) , if 
50 percent or more of the plants have some aphids (a few heavy) and if the corn 
is under stress (from low soil moisture, fertility, disease, etc.). Continue to 
watch the infestation as long as growing conditions are good; if 15 percent or 
more of the plants become heavily loaded with aphids, treat immediately. 

Seed fields should be treated if 50 percent or more of the plants have some 
aphids (only a few heavy), even if the corn is not under stress. In general, 
applications after all the silks have dried are disappointing. 



Spray treatments by ground or air with 1 pound of malathion or diazinon per acre 
will control the aphids. When using malathion, allow 5 days between treatment 
and harvest for grain, ensilage, or stover. Using diazinon, there is no waiting 
period between treatment and harvest for grain, but allow 10 days to elapse be- 
fore making ensilage or stover. If corn is still in the late-whorl stage, seed 
producers may prefer to use 1 pound of either diazinon or phorate (Thimet) per 
acre as granules. To avoid potential hazards to detasselers, use phorate only 
on male-sterile corn. 

Corn rootworm larval populations are continuing to increase in cornfields as tiny, 
-ecently hatched worms can be found in northern Illinois. Eggs are still hatch- 
ing and the number of larvae is expected to increase or remain constant for 
another one or two weeks. Pupation of worms is progressing rapidly in many 
fields and adults are emerging. One field in northern Illinois increased from 
45 worms per hill on July 10 to 101 per hill on July 17. 

Goosenecking of corn plants, as a result of larval damage, is now evident in 
many infested cornfields. Wilting and dying plants were observed in some heavily 
infested fields. 

Northern corn rootworm adults are beginning to emerge from the soil in corn- 
fields where rootworms have been feeding on the roots of corn plants in the 
northern and central sections of the state. These green beetles feed on fresh 
silks and may reduce pollination. 

Western corn rootworm adults are also emerging and they do the same damage. These 
yellow- and black- striped beetles will appear in the northwestern section of the 
state. Both of these insects will be emerging during the next few weeks. Treat- 
ment is justified if there are 5 or more beetles per plant and if not over 50 per- 
cent of the plants have silked. This situation is likely to exist in many fields 
about August 1. The beetle population will continue to increase until mid-August. 

Sprays of carbaryl (Sevin) , diazinon, or malathion at 1 pound actual insecticide 
or 1/4 pound of methyl parathion per acre are effective. Methyl parathion should 
be applied by experienced applicators only . Allow 5 days between treatment and 
harvest for malathion, 10 days for diazinon, and 12 days for methyl parathion; 
carbaryl has no waiting period. 

European corn borers have almost completed pupating and are also emerging as moths 
in the southern half of Illinois. Pupation is just beginning in the northern 
sections. Second -generation infestations in late cornfields can be handled the 
same as the first-generation situation: If 75 percent of the plants show whorl 
feeding, apply carbaryl (Sevin) or diazinon granules. If the corn has tasseled, 
look for egg masses on the leaves. If the average is 1 or more per plant, apply 
an insecticide when a few eggs have begun to hatch. 

True arm^vorms have been observed in grassy cornfields in the northern half of 
Illinois. Watch such fields closely; the worms feed first on the grass and then 
move onto the com plant. For infestations, apply carbaryl (Sevin) or toxaphene. 

If you use carbaryl (Sevin) , there is no waiting period between application and 
harvest of the crop for grain or ensilage. If you apply toxaphene, there is no 
restriction on use of grain, but do not feed treated forage to dairy animals. 
) not feed ensilage, fodder, or stover to livestock within 28 days of slaughter. 



-3- 

Woolybears and other leaf- feeding bristly caterpillars are being observed feeding 
on corn leaves and silks. Control with insecticides is seldom needed for these 
insects . 

Soybean Insects 

Green cloverworms are present in some soybean fields in central and northern 
Illinois. These pale, green worms with white stripes "spring" or jump by rapidly 
curling and uncurling their body. Damage is not apparent, but the situation bears 
watching . 

Small-Grain Insects 

Cereal leaf beetles were recently found in Moultrie County, as well as in those 
counties previously reported. A survey of all 102 counties for this insect has 
now been completed by the Plant Industry Division, Illinois Department of Agri- 
culture and the Plant Pest Control Division, USDA. 

Forage Insects 

Young grasshoppers are present in occasional fencerows, roadsides, and ditches, 
grass waterways and hay fields. They will remain in these areas as long as suc- 
culent plant growth is present for feeding. When the growth begins to turn brown, 
these insects will migrate into adjoining soybean and cornfields. 

Since egg hatch is complete, there is only one generation per year and they are 
concentrated in small areas. Chemical control of these young 'hoppers is most 
economical and easiest before they migrate into the field crops. Treating these 
areas with carbaryl (Sevin) at 3/4 pound per acre as a spray is best for grass- 
hoppers. Diazinon at 1/2 pound, malathion at 1 pound, and naled (Dibrom) at 3/4 
pound per acre are also effective. When treating forage crops, allow 7 days be- 
tween treatment and harvest with diazinon, 4 days with naled; there is no waiting 
period for malathion or carbaryl. 

Homeowner Insect Problems 

Sod webworm moths , which are buff colored, have been observed flying over lawns 
in towns in the southwestern section of the state, and they are beginning to 
appear in the central section. This flight is the second-generation of moths. 
They are laying eggs as they fly in a zigzag pattern just above the lawn. If you 
notice large numbers of these moths, plan to treat your lawn with an insecticide 
about 2 weeks later. 

The larvae of the webworm are a gray worm with small brown spots over their back 
and a black head. They are about an inch long when mature, and live for about 
4 weeks as a larva. The worms live in silken-lined burrows in the thatch of the 
lawn, clipping off the grass blades at the base. Brown spots appear in the lawn 
when worms are numerous, and large numbers of robins will move in to feed on the 
larvae. By this time, it is usually too late for control. 

To control sod webworms , apply as a spray: (1) 2 pounds of actual carbaryl (Sevin), 
(2) 1 pound of diazinon, or (3) 1-1/4 pounds of trichlorfon (Dylox) per 10,000 
square feet (1/4 acre). Apply the amount of insecticide suggested in at least 
25 gallons of water, and do not water the lawn for 3 days after treatment. Gran- 
ular forms of the same insecticides applied from a fertilizer spreader can be 
used in place of the spray. 



-4- 

Aphids are still prevalent on many shrubs and in some trees. They are soft-bodied, 
sucking insects that are easily controlled with malathion (50- to 57-percent liquid 
concentrate) or with diazinon (25-percent liquid concentrate, using 2 teaspoons of 
either chemical per gallon of water) . 

Picnic beetles continue to be uninvited guests at cookouts, picnics, and in and 
around the home. The black beetles with four yellow spots are attracted to the 
odor of food, especially overripe and decaying produce. Also, they are present 
around garbage cans. 

For control in home yards, harvest fruits and vegetables before they become over- 
ripe. Dispose of any spoiled produce. To kill the adult beetles, spray with 
malathion, diazinon, or carbaryl (Sevin) on and around garbage cans. Spraying 
shrubbery and tall grass with the same insecticides before a cookout will greatly 
reduce the number of these beetles. Follow directions on the label; check plants 
that may be injured if sprayed with the insecticide you are using. Either 0.1- 
percent pyrethrin or 0.5-percent dichlorvos (DDVP) in pressurized spray cans will 
give a quick knockdown of beetles that suddenly move into an area. 

PLANT DISEASES 

The plant-disease situation in field crops has remained about the same as given 
in the last two issues. 

WEEDS 

A lot of soybean fields look quite clean this year. The delayed planting, use of 
herbicides, rotary hoeing, and good cultivation have all contributed. 

Now is a good time to chop that volunteer corn out of soybeans. Relatively few 
fields have a serious problem. 

As the beans stop growing, some of the taller-growing weeds (like velvetleaf) will 
become more evident. Fulling these to prevent seed production will be well worth- 
while in many fields. Pulling may not sound very "glamorous," but is still 
practical and economical in many fields. (And it will give kids something to tell 
their grandchildren.) 

Corn has made tremendous growth in the last few weeks. There are still some appli- 
cations of 2,4-D with "high boy" sprayers. Even though this is a low-cost practice, 
there is no need to spray unless you really do have susceptible, broadleaved weeds 
present. In spite of the problems we've had with 2,4-D this year, we still say 
that weed control is usually better and competition less if weeds are sprayed when 
they are small, rather than waiting until it is too late. 

The common recommendation is not to spray when corn is silking and pollinating. 
We usually don't have much of a problem in this regard- -perhaps because most folks 
do avoid spraying then. 

With the small grain harvested, weeds such as foxtail and ragweed now have a chance 
for more-vigorous growth. If you don't plan to work the fields for a while, con- 
sider clipping or spraying to reduce the weed seed production. If you don't have 
a grass or legume seeding, consider spraying. A low-cost application of 2,4-D can 
check most broadleaved weeds. A few pounds of Dowpon per acre- -alone or added to 



-5- 

2,4-D--can reduce the seed production of grasses considerably. The smaller the 
grass, the less Dowpon you'll need. If weeds have made much of a growth, it may 
pay to clip or chop the stubble before spraying. 

If you have Johns ongrass in wheat stubble and plan to plant corn or soybeans in 
the field next spring, consider a Dowpon application now for control. Clipping 
or chopping the Johnsongrass a time or two before spraying will help deplete the 
food reserves in roots and rhizomes; this generally improves control. 

When the Johnsongrass is about a foot high and is actively growing during warm 
moist weather, spray with 8 pounds of Dowpon in 50 to 40 gallons of water per acre, 
Wait at least a week or two before working the soil, in order to give the Dowpon 
plenty of time to translocate and act on the roots and rhizomes. Unless the 
Johnsongrass is making good, active growth when sprayed, results may be disap- 
pointing. 

By spraying Johnsongrass this summer, you can control much of the old Johnsongrass 
without delaying planting next spring. But you should plan to follow up next 
spring with a preemergence application of Eptam for corn or Treflan for soybeans, 
to control Johnsongrass that may come from seed. See Illinois Circular 827 for 
more details on Johnsongrass control. 

If you see dead clumps of Johnsongrass along roadsides and in other non-crop areas, 
it means somebody is doing a good job of spraying. Find out who it is and pat 
them on the back. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Cereal Leaf Beetles: T.J. Lanier, USDA, Plant Pest Control. 

Plant Diseases: M.P. Britton and M.C. Shurtleff, Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy. 

Ag Communications: Del Dahl. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



/' u I 




INSECT 

SURVEY 

BULLETIN 



8 







ft/ry M w* 



^ 



tate / County / Local Groups 



FOR IMMEDIATE RELEASE 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 

JUL 2 9l96|o 



July 26, 1968 



ILLINOIS INSECT, DISEASE, AND WEED SURVEY BULLETIN NO. 20 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 

THE LIBRARY I 



INSECTS 



AUG -1 



Corn 

[;.■_:_'_.-._:,: ;... li LihiiiS 
Corn leaf aphids are still present in most cornfields in light to moderate num- 
bers. A few fields have heavy populations. Fields still in the late-whorl or 
early-tassel stage are the most critical, especially if soil moisture is low. 
Fields of corn with fully exposed tassels and in which pollen shed is about com- 
plete will probably escape damage, unless infestations are extremely severe. In- 
festations in these fields are already beginning to decline. 

Examine fields of corn in the late-whorl to early-tassel stage, especially if the 
soil moisture has been less than adequate. 

To examine a field for aphids, (1] pull 25 whorls in four places in a field, 
(2) unroll the leaves, and (3) determine the percent of infested plants and degree 
of damage. If the next two weeks are hot and dry, the population of aphids is 
most likely to increase greatly- -decreasing with cool, rainy weather. We have 
observed very few predators. The black beetles with the four yellow spots, com- 
monly seen in the whorl, are picnic beetles. They are not predators and do not 
damage plants . 

Treatment is justified on late -whorl -stage corn (a few tassels showing), if 50 per- 
cent or more of the plants have some aphids (a few heavy) and if the corn is under 
stress (from low soil moisture, fertility, disease, etc.). Continue to watch the 
infestation as long as growing conditions are good; if 15 percent or more of the 
plants become heavily loaded with aphids, treat immediately. 

Seed fields should be treated if 50 percent or more of the plants have some aphids 
(only a few heavy) , even if the corn is not under stress. In general, applica- 
tions after all the silks have dried are disappointing. 

Spray treatments by ground or air with 1 pound of malathion or diazinon per acre 
will' control the aphids. Allow 5 days between treatment and harvest for malathion 
and 10 days for diazinon. If corn is still in the late-whorl stage, seed producers 
may prefer to use 1 pound of either diazinon or phorate (Thimet) per acre as 
granules. To avoid potential hazards to detasselers, use phorate only on male- 
sterile corn. 



-2- 

Corn rootworm adults are feeding on silks in many cornfields throughout the state. 
The tan or pale -green northern rootworms, 12-spotted southern ones, and yellow- 
and-black (often striped) western rootworms all feed on silks. The western corn 
rootworm was found for the first time in Brown County this week. In the primary 
rootworm problem area (the northern half of the state) , as many as 5 or more 
beetles per silk were observed in some fields this week. Adult emergence varies 
from 10 to 40 percent in these fields, so adult populations will increase as the 
beetles continue to emerge. In most of these problem fields, lodging is already 
noticeable and root damage is severe, due to root pruning by the larvae. 

When beetles are numerous, they can interfere with pollination. The injury will 
probably be more severe in medium- and late-maturing fields, since adult root- 
worms are likely to be higher in these fields during the critical pollinating 
period. 

Treatment for adult rootworms is justified if there are 5 or more per silk, and 
if not over 50 percent of the plants have silked. Sprays of carbaryl (Sevin) , 
diazinon, or malathion at 1 pound of actual insecticide or 1/4 pound of methyl 
parathion per acre are effective. Methyl parathion should be applied by expe - 
rienced applicators only . Allow 5 days between treatment and harvest for mala- 
thion, 10 days for diazinon, and 12 days for methyl parathion; carbaryl has no 
waiting period. Sprays of malathion, methyl parathion, and diazinon will also 
control corn leaf aphids, while carbaryl will not. 

We have been receiving calls from farmers who have not previously had rootworm 
problems. Most such problem fields had received an aldrin or heptachlor treat- 
ment that did not control the rootworms. Rootworm resistance to aldrin and 
heptachlor has now become widespread in Illinois; hence, these insecticides can 
no longer be depended on for rootworm control. In general, the phosphate and 
carbamate insecticides used this past spring for the control of resistant root- 
worms are providing satisfactory results. Within the next week or two, it would 
be wise to check your corn (particularly continuous corn) for rootworm damage and 
for the presence of adult beetles, if you have not already done so. 

You can best determine the need for a rootworm control program for next year by 
making an estimate of the adult rootworm population at this time. Make a count 
of the average number of beetles per plant when the corn is in full silk. An 
average of 5 to 10 or more adults per plant is probably enough to cause economic 
losses in 1969, if the field is planted to corn again. Although not fool proof, 
this is the best, current rule of thumb we can give you for predicting rootworm 
problems for next year. 

Notify your local county Extension adviser about severely damaged fields, espe- 
cially if you have had failures with the organic phosphate or carbamate insecti- 
cides used for the control of resistant rootworms. Also, report any fields of 
first-year corn that have been bothered by rootworms. 

Second-generation European corn borer moth emergence is well under way in southern 
sections, and eggs are being laid. Emergence is just beginning in the central 
section. Pupation ranges from 15 to 30 percent in the northern section. Now is 
the time to check late-maturing fields for egg masses and whorl feeding in the 
southern section. Wait about a week in the central section, and about 2 weeks in 
the northern section. Treat whorl-stage corn if 75 percent or more of the plants 
show recent whorl feeding. Treat tasseled corn if the egg masses per plant average 



one or more. Apply the treatment at first egg hatch. Use either 1-1/2 pounds of 
carbaryl (Sevin) or 1 pound of diazinon as a granule or spray. On whorl -stage 
corn, aerial applications should be granules, not sprays. Aerial sprays on tas- 
seled corn are effective. Allow 10 days to elapse before making ensilage or 
stover when using diazinon. Carbaryl has no waiting period. 

Corn-blotch leaf miners , tunneling between the leaf tissues, were especially 
noticeable on the lower leaves of corn in some areas this week. The tunnels 
appear as transparent galleries, and may be confused with corn leaf diseases. 
By carefully separating the leaf tissue, you can often find a small 1/16- to 1/4- 
inch, green- to-white maggot or a reddish brown pupa inside. This leaf mining 
seldom consumes a very large portion of the leaf, and only a few leaves per plant 
are involved. Damage done by this insect is believed to be of little or no eco- 
nomic importance. No control is recommended. 

Soybeans 

Green cloverworm populations have increased in soybeans . They strip the leaves 
but do not attack the pods, as do grasshoppers and bean leaf beetles. Damage is 
most severe when defoliation occurs while bean pods are filling and while the 
beans are mature but still green. Moderate defoliation- -less than 40 percent-- 
occurring before bloom or after the beans are mature will not affect the yield 
significantly. 

As a rule-of -thumb, we feel that an average of 6 or more worms per linear foot of 
drill row during the period of pod development justifies treatment. To determine 
the field average, shake the plants over the center of the row and count the worms 
in" several places in the field. Use 1-1/2 pounds of toxaphene or 1 pound of 
carbaryl (Sevin) per acre to control this insect. When using toxaphene, the beans 
should not be harvested for 21 days after spraying. Do not feed toxaphene- 
treated soybeans as forage to dairy animals or to livestock being fattened for 
slaughter. Carbaryl has no waiting period or feeding restrictions. 

Livestock Insects 

Face fly populations continue moderately high on pastured cattle in the central 
and south-central sections. In the area between Route 460 and Route 9, pastured 
cattle averaged 20 to 40 flies each. Cattle show annoyance from face flies when 
10 to 15 flies per animal are present. Cattle on tight, dry- lot confinement are 
not bothered by face flies. 

For dairy cattle, apply Ciodrin as a 2 -percent oil or water-base spray at 1 to 2 
ounces per animal two to four times per week. An automatic sprayer, a small 
electric mist-type sprayer (not fogger) , or a hand sprayer can be used. Apply 
the spray over the entire animal, including the legs. Ciodrin is the most effec- 
tive insecticide for face fly control, and it will also eliminate horn flies and 
reduce the number of stable flies. 

For beef cattle, the use of an automatic sprayer with Ciodrin as suggested for 
dairy cattle should be considered. If this is impractical , use a 1-percent 
Ciodrin-water diluted spray at 1 to 2 pints per animal, as often as once a week 
if needed. Canvas or burlap head oilers and face or back oilers, saturated with 
a 5-percent toxaphene in oil solution, will provide some relief to cattle. Do 
not treat cattle under 4 months of age with toxaphene, and do not apply it within 
28 days of slaughter. 



Homeowner Insect Problems 

Fall webworms are spinning webs around the ends of branches on shade trees- -espe- 
cially birch, ash, and elm. Pale green or yellow worms with a dark stripe down 
the back and a yellow stripe along each side skeletonize the foliage inside the 
web nest. They continue to extend the web to take in fresh foliage. The damaged 
leaves turn brown, curl, dry up, and eventually die. 

Spraying with 50-percent carbaryl (Sevin) at the rate of 2 tablespoons per gallon 
of water is effective. 

Picnic beetles are thick in cornfields and around homes. These black beetles 
with four yellow spots on their back eat decaying material in the galleries of 
corn borer and feed on the sticky secretions left by aphids on corn. Around the 
home, they are attracted by cooking odors or to garbage containers, as well as 
to overripe fruits and vegetables in the garden. They are a real nuisance at 
cookouts , picnics , and outdoor barbecues . 

For control in home yards, harvest fruits and vegetables before they become over- 
ripe; dispose of any spoiled produce. To kill the adult beetles, spray with 
malathion, diazinon, or carbaryl (Sevin). Follow directions on the label for 
dosages, and observe the specified waiting periods between treatment and harvest. 
For beetles, a spray-can application of either 0.1-percent pyrethrin or 0.5- 
percent dichlorvos (DDVP) will give a quick knockdown. Spray the mist lightly 
beneath tables and chairs and into the air for a few feet around the area. Apply 
the same mist over the top and around the sides of garbage containers. 

Both the imported and looper cabbage worms are feeding on the outer leaves of 
cabbage heads, or may be eating their way into the head. These worms are dif- 
ficult to control when they are more than half grown. Spraying with carbaryl 
(Sevin) or malathion while the worms are small will give adequate control. Allow 
7 days between the last application and harvest when using malathion, and 3 days 
for carbaryl. 

PLANT DISEASES 

Corn 

A few fields of corn have been seen in which a high number of plants have the 
"crazy top" disease. This fungus disease is soil borne. Infection occurs only 
in low, wet spots in fields. 

The symptoms are a general stunting of the plant and yellow streaking of the 
leaves, followed by death of the leaves. As the tassels form, they are often 
leafy, showing the typical "crazy top" symptom. 

Soybeans 

Bacterial blight is severe on soybean leaves in many fields throughout the northern 
half of Illinois. It is recognizable by the angular leaf spots, usually sur- 
rounded by a narrow zone of yellow leaf tissue. The dead spots tend to fall out 
of the leaves, and severely infected leaves may have a ragged appearance. 

Phytophthora blight is present in low spots in soybean fields planted to suscep- 
tible varieties. This disease can be identified by the complete killing of plants 
in low spots. Plants of any size may be killed. 



WEEDS 

Is It Too Late To Spray Corn With 2,4-D? 

Most 2,4-D labels say not to spray corn from the tasseling to the dough stage. 
Whether or not the corn is subject to much injury at that stage is somewhat con- 
troversial. Based on field studies and observations, it is difficult to establish 
that 2,4-D has much of a direct effect on silks that would interfere with fertil- 
ization. And, under field conditions, it is rather difficult to study the effect 
of 2,4-D on pollen viability. Conceivably, 2,4-D that has translocated in the 
plant might affect silking and tasseling, even though it was not directly applied 
to the silks and tassels. 

Mid-season hybrids silk about 60 to 70 days after corn emergence- -depending on 
the hybrid, the season, and the date of planting. If plenty of pollen is avail- 
able, the silks are pollinated soon after they emerge from the husks. But where 
stands are uneven, the time for pollen shed and silk emergence can be extended. 

About two weeks after the silks emerge they will be dry. The plant reaches the 
dough stage about 3 to 4 weeks after the silks emerge. 

To be on the safe side, it is best to follow the indicated label precautions and 
not spray from the tasseling to the dough stage . This is a crucial stage in the 
development of the corn plant. 

In addition, large weeds are competing with the crop by late July and August. 
They may have already formed viable seed, and they are not easily controlled. 
Dense shade in high -population fields can considerably depress the growth of 
many weeds. 

While you may have more time to spray 2,4-D now, your control would have been 
much better in most fields if you had used 2,4-D earlier. Also, there is still 
some risk of 2,4-D making corn brittle and causing injury. 

A "Color Chart for Estimating Organic Matter in Mineral Soils in Illinois" (AG 1941) 
is available from the Office of Publications, College of Agriculture, University 
of Illinois, Urbana, Illinois 61801. 

The chart, prepared by John Alexander of the Agronomy Department, can help you 
estimate the organic -matter content of soils on the basis of color. The guide 
should also be of considerable help to you in determining the appropriate herbi- 
cide rates for adequate weed control, as well as minimum cost and residue. 



NOT FOR PUBLICATION 



Special Note to County Extension Advisers, South-Central and Southern 

Two field meetings especially for county Extension advisers will be held on the 
identification, damage, and control of the European corn borer. We invite you to 
attend. 

Tuesday, July 30 Bond County Extension Adviser's Office, 1:00 p.m. 

Wednesday, July 31. . .Richland County Extension Adviser's Office, 1:00 p.m. 



-6- 

READ TIE LABEL AND FOLLOW ALL PRECAUTIONS 



This weeklv report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy. 

Ag Communications: Del Dahl. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 




INSECT 

SURVEY 

BULLETIN 



ABT£*fe 







.0 



FOR IMMEDIATE RELEASE 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 

U. S.lft<MBRAR¥iflFifH&f Agriculture Cooperating 

AUG 1 9 1368 



imwrniv flf immiQ 



August 2, 1968 



ILLINOIS INSECT, DISEASE. AND WEED SURVEY BULLETIN NO. 21 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) 3 along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. • PRmtY Or THE 



INSECTS 



AUa -J 



13B9 



torn 



WMM HE ILLINOIS 

Corn leaf aphids increase rapidly in number in corn from pretassel to late silking. 
How soon will these aphids decrease? They decrease after pollination has occurred. 
After silks are dry, they disappear rapidly from the field. 

Several other questions are being asked. The white objects in the aphid colony 
are the shed skins of aphids- -not dead aphids or aphid eggs. There are no aphid 
eggs. In fact, there are no male aphids during the summer months. All aphids are 
females that give birth to living young. The black on the corn plants Is sooty 
mold growing on the honey-dew secretion of the aphids. This is also present on 
plants without aphids. This sooty mold will wash off with rain and the plants will 
look greatly improved. 

Stress on the corn plant is all important. A drought during an aphid outbreak can 
be extremely serious. If plant roots are pruned for any reason (as by rootworms) , 
the aphid damage will be greater than to plants with normal root systems. 

In general, the aphid situation is not serious in most areas of adequate moisture, 
because the light to moderate infestations are not damaging. Some people become 
excited and refer to light or moderate infestations as "heavily loaded plants." 
A heavily loaded plant is one with the tassel plus several of the upper leaves 
literally coated with aphids. 

This week, aphid populations decreased rapidly in fields already pollinated, and 
they started to decrease in fields that were pollinating. Fields in the late- 
whorl or early tassel stage should be observed carefully this week. 

Treatment is justified on late-whorl- stage corn (a few tassels showing), if 50 
percent or more of the plants have aphids (a few heavy) and if the corn is under 
stress (from low soil moisture, fertility, disease, etc.). Continue to watch the 
infestation as long as growing conditions are good; if 15 percent or more of the 
plants become heavily loaded with aphids, treat immediately. 



-2- 

Corn rootworm adults are increasing in abundance in cornfields, and there are more 
to come before emergence is complete. The tan or pale-green northern rootworms, 
the yellow and black-striped western ones, and the 12-spotted southern rootworms, 
all feed on silk. In most fields, pollination is complete and silk feeding is no 
longer important. We observed a few heavily infested fields of western rootworms 
(15 to 20 or more beetles per plant) , where the adults were feeding on the silks 
as well as skeletonizing leaves and feeding on brace roots. In these fields, the 
root pruning by the larvae was so severe that some corn plants were dying. The 
western corn rootworm infestations appear to be most severe in fields of second- 
year corn, while northern corn rootworm infestations seem most severe in fields 
where corn has been planted for 3 or more years in succession. 

In most fields, treatment with insecticides at this time will not be profitable. 
But in late fields, where pollination may still be affected by silk feeding, or 
in those where adults are extremely numerous and are damaging ear tips, treatment 
may still be justified. Treatment for adults is recommended only if there are 
5 or more beetles per ear, and if not over 50 percent of the plants have silked. 
Sprays of carbaryl (Sevin), diazinon, or malathion at 1 pound of actual insecti- 
cide or 1/4 pound of methyl parathion per acre are effective. Methyl parathion 
should be applied by experienced applicators only . Allow 5 days between treat- 
ment and harvest for malathion, 10 days for diazinon, and 12 days for methyl para- 
thion; carbaryl has no waiting period. Sprays of malathion, methyl parathion, and 
diazinon will also control corn leaf aphids, while carbaryl will not. 

Do not expect a single insecticide application for adult control to significantly 
reduce the number of larvae that will be present in the field next year. Migra- 
tion of the adult beetles from adjacent fields and prolonged emergence will pro- 
vide sufficient eggs to cause economic problems in 1969, if the field is planted 
to corn again. However, it is possible that two or more applications may kill 
enough adults now to reduce larval numbers next year. 

European corn borer moths are now present in most areas. In north-central and 
northern Illinois, egg laying will not really be underway for several days yet; 
egg laying has just begun in central Illinois. First -generation populations were 
low in these areas. Severe second- generation damage is not expected. 

However, many fields in south- central Illinois were infested by first-generation 
borers. Second-generation moths are numerous in this area, and egg laying will 
progress rapidly during the next 2 weeks. Many fields now in the late-whorl stage 
will be favored by the moths for egg laying. Watch such fields closely; some late- 
planted cornfields may be severely damaged. 

If you find small worms in the whorls of 75 percent of these plants, an application 
of an insecticide will be justified. In the more-mature fields, count egg masses. 
If there is an average of 1 egg mass per plant, insecticide applications will be 
profitable. Apply insecticides at first egg hatch. 

Use either 1-1/2 pounds of carbaryl (Sevin), or 1 pound of diazinon, as a granule 
or spray. On whorl-stage corn, aerial applications should be granules, not sprays. 
Aerial sprays on tasseled corn are effective. Allow 10 days to elapse before making 
ensilage or stover when using diazinon. Carbaryl has no waiting period. 



Southwestern com borer is abundant in bottomland fields of very late corn in the 
southern tip of Illinois. Now is the time to apply insecticides. If 25 percent 
of the whorls show feeding from this borer and small borers are found in the whorl, 
apply either 1 to 2 pounds of actual diazinon or 2 pounds of carbaryl (Sevin) per 
acre. If applying by air, use granules; they will roll into the whorls and get in 
behind the leaf sheaths. Some states also recommend EPN granules. With diazinon 
granules, wait 10 days before harvesting the crop. There is no time limit on the 
use of carbaryl. There is a 14-day waiting period when using EPN. 

Corn flea beetles are extremely abundant in cornfields in the southern half of 
Illinois. Their feeding alone is not of importance, but they could be transmit- 
ting Stewart's disease or blight. This will appear as brown, dry, lower leaves 
within the next few weeks. Control of flea beetles now will not reduce the inci- 
dence of disease, so no control is recommended for flea beetles. 

Fall armyworms are present in some late-maturing cornfields. The dull-green to 
brown, smooth- skinned worms feed in the whorl, leaving ragged holes in the leaves. 
Several plants in one area will be damaged, and there is usually only one worm 
per plant. The worms were about half grown this week in the south-central section. 
IVhen mature, the worms drop to the ground and pupate in the soil. Unless the field 
is heavily infested (25 percent or more) , treatment is not profitable. If the in- 
festation is severe and the worms still present, carbaryl or toxaphene at 1-1/2 
pounds per acre as granules will give control. Do not feed toxaphene- treated corn 
as forage to dairy cattle or to livestock fattening for slaughter. The corn grain 
may be fed. 

Cattail caterpillars --orange- striped, brown and black, bristly worms- -are present 
in some fields of corn. They feed along the leaf margins, chewing out large areas 
similar to grasshoppers. Seldom are they numerous, probably because a wasp para- 
sitizes many of the worms and kills them. No control measures have yet been nec- 
essary. 

Soybeans 

Green cloverworms continue to be a problem in many soybean fields, particularly in 
the northern two -thirds of the state. All sizes of worms are present, but many of 
them still tiny. They strip the leaves --especially the newer, more-tender top 
leaves, but do not attack the pods or blossoms. Severely damaged fields take on 
a grayish to whitish cast. Damage is most severe if defoliation occurs when the 
pods are half filled. Most beans are now in the early pod- forming stage. A few 
parasitized worms were observed this week, but in general, the worm populations 
are healthy. 

Treatment is justified if there are 6 or more worms per linear foot of drill row 
during the period of pod development. This is particularly true if 25 percent of 
the leaf surface has already been eaten. To determine the field average, shake 
the plants vigorously over the center of the row and count the worms in several 
places in the field. Use 1 pound of carbaryl (Sevin) or 1-1/2 pounds of toxaphene 
per acre to control this insect. Toxaphene is slow-acting, so wait about 4 days 
after spraying before judging its effectiveness. The beans should not be harvested 
for 21 days after spraying with toxaphene. Do not feed toxaphene- treated soybeans 
as forage to dairy animals or to livestock being fattened for slaughter. Carbaryl 
has no waiting period or feeding restrictions. 



Potato leafhoppers are extremely abundant in soybeans. Damage may appear as brown- 
ing of the leaf margins and stunted or misshapened appearance of the plants. Rarely 
is control recommended for these tiny, green, wedge-shaped insects. If damage has 
become noticeable, however, you may want to control them with malathion, carbaryl, 
or toxaphene. Control measures for green cloverworms will control these leafhoppers 
and will add to the benefits derived from cloverworm control. Do not feed toxaphene- 
treated soybeans as forage to livestock. Do not harvest malathion- treated soybeans 
for 5 days after treatment. 

Stinkbugs are numerous in some soybean fields, particularly in southern sections. 
Find a large semielliptical green or brown insect that is shaped somewhat like a 
shield and smash it. The name indicates the way to identify the bug. These bugs 
will attack developing pods, sucking the sap from them with their long, stout beaks. 
They cause shrinking, dimpling, and underdevelopment of the beans; sometimes, pods 
without any beans. They are also capable of transmitting yeast spot disease. Most 
farmers usually do not become concerned about stinkbugs until harvest time, when 
beans are down-graded because of damage. 

USDA research workers have found that an average of 1 stinkbug per yard of row will 
reduce the yield by 10 percent. If stinkbugs are numerous and control is needed, 
apply 1 pound of carbaryl (Sevin) or malathion per acre. When using malathion, 
allow 5 days to elapse between treatment and harvest. 

Livestock Insects 

Fly populations are high on untreated pastured cattle throughout the state. Blood- 
sucking flies, like the horn fly , are averaging between 300 to 500 per animal in 
the southern section, 100 to 200 in the central section, and 50 to 150 in the 
northern section. Stable flies are also present, with an average population of 12 
per animal. Annoying flies, like the face fly , are highest in the area between 
route 460 and route 9, where 20 to 40 flies per animal are common. Runny eyes and 
problems with pink eye and conjuctivitis are noticeable where face flies are abun- 
dant. Young calves seem to suffer the most. 

For dairy cattle, apply Ciodrin as a 2-percent oil or water-base spray, at 1 to 2 
ounces per animal, two to four times per week. An automatic sprayer, a small, 
electric mist-type sprayer (not a f ogger) , or a hand sprayer can be used. Apply 
the spray over the entire animal, including the legs. Ciodrin is the most effec- 
tive insecticide for face- fly control; it will also eliminate horn flies and reduce 
the number of stable flies. 

For beef cattle, the use of an automatic sprayer with Ciodrin as suggested for 
dairy cattle should be considered. If this is impractical, use a 1-percent Cio- 
drin, water- diluted spray, at 1 to 2 pints per animal, as often as once a week if 
needed. Canvas or burlap head oilers and face or back oilers, saturated with a 
5-percent toxaphene in oil solution, will provide some relief to cattle. Do not 
treat cattle under 4 months of age with toxaphene, and do not apply it within 28 
days of slaughter. 

WEED CONTROL 

Where Treflan was applied to soybeans in 1967 , we had several cases of injury to 
corn earlier in 1968. Some of the injury could be explained by excessive applica- 
tions, particularly on field ends. In the majority of fields showing injury, soy- 
bean stubble was not plowed with a moldboard plow prior to planting corn. The 



-5- 

problem is not considered extremely serious, and much of the corn recovered sur- 
prisingly well. However, as an added precaution, it would be well to consider 
conventional plowing where fields treated with Treflan this year will be planted 
to corn next year. 

If you used atrazine and oil in June this year, consider planting corn rather than 
soybeans in the field next year. Applying atrazine relatively late decreases the 
amount of time for herbicide decomposition and increases the possibility of damage 
to soybeans next year, especially if the soybeans are planted early. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Weeds: Ellery Knake, Department of Agronomy. 

Ag Communications: Del Dahl . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



NOTE TO COUNTY EXTENSION ADVISERS 

This year, we had corn rootworm control demonstrations in 7 counties. These 7 
advisers applied several insecticides at planting time. We helped rate these 
plots. Several counties have asked about demonstration plots of standard recom- 
mendations for next year. We now plan to organize such plots. If you are inter- 
ested in having one in your county in 1969, select possible fields now. Count 
the number of beetles per plant or per ear. Find several fields that have more 
than 10 beetles per plant. One of these may then be selected for next year, de- 
pending on the ease of obtaining harvest records, the evenness of field, availa- 
bility, etc. Let us know your plans. 




INSECT 

SURVEY 

BULLETIN 






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College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



County 



Local Groups 



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FOR IMMEDIATE RELEASE 



U- flft LB$t8HF n Wt' i of ii»aticulture Cooperating 

AUG 19 1958 



August 9, 1968 



ILLINOIS I NSECT. DISEASE. AND WEED SURVEY BULLETIN NO. 22 

This series of weekly bulletins provides a general look at the insect, plant dis- 
ease, and weed situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
field to determine local conditions. 

CORN INSECTS 

Corn leaf aphid populations decreased rapidly this past week in fields where pol- 
lination is complete. Ocassionally, such fields still have a high number of 
aphids. Aphids can also be found in moderate to heavy numbers in late-maturing 
fields that are still in the late-whorl to early silk stage. Adult, winged aphids 
are especially common in these later-maturing fields, as they have migrated from 
the earlier maturing fields. 

Treatment is justified on late-whorl-stage corn (a few tassels showing) if 50 per- 
cent or more of the plants have aphids (a few heavy) and if the corn is under 
stress (from low soil moisture, fertility, disease, etc.). Continue to watch the 
infestation as long as growing conditions are good; if 15 percent or more of the 
plants become heavily loaded with aphids, treat immediately. 

Corn rootworm adults are abundant in many fields in the northern half of the 
state. The western corn rootworm was found for the first time in Kankakee County 
last week, and this week in LaSalle County. If you live in a county where western 
corn rootworms are not known to be present, take any specimens resembling this in- 
sect to your county Extension adviser in agriculture for identification. 

In most fields, treatment with insecticides at this time will not be profitable. 
But in late fields (where pollination may still be affected by silk feeding) or 
in fields where adults are extremely numerous and are damaging ear tips, treat- 
ment may still be justified. Treatment for adults in late-maturing fields is 
recommended only if there are 5 or more beetles per ear, and if not over 50 per- 
cent of the plants have silked. Sprays of carbaryl (Sevin) , diazinon, or mala- 
thion at 1 pound of actual insecticide or 1/4 pound of methyl parathion per acre 
are effective. Methyl parathion should be applied by experienced applicators only . 
Allow 5 days between treatment and harvest for malatnion, 10 days for diazinon, 
and 12 days for methyl parathion; carbaryl has no waiting period. Sprays of 
malathion, methyl parathion, and diazinon will also control corn leaf aphids, 
while carbaryl will not. 

Do not expect a single insecticide application for adult control to significantly 
reduce the number of larvae that will be present in the field next year. Migra- 
tion of the adult beetles from adjacent fields and prolonged emergence will provide 



-2- 

sufficient eggs to cause economic problems in 1969, if the field is planted to 
corn again. However, it is possible that two or more applications may kill 
enough adults now to reduce the number of larvae next year. 

European corn borer moths seem to be abundant in some areas of north-central 
Illinois; this indicates a greater potential second-generation population than 
previously expected. In northern sections, about 70 percent of the second- 
generation moths had already emerged this week. Egg-laying will continue in the 
central section for another week or two, and in northern sections for another 
2 to 3 weeks. Late-maturing fields should be checked for the presence of the 
borer eggs. An average of 1 egg mass or more per plant is sufficient to justify 
an insecticide treatment. Make the application at first egg hatch. 

SOYBEAN INSECTS 

Green cloverworms are being killed by a fungus disease and parasitic flies. Worms, 
dead from disease, are white to tan, and the body tissues are hard (mumif ied) . 
High temperatures and humidities have provided ideal conditions for the spread and 
development of this disease and the sudden decline in worm numbers in some fields. 
The incidence of disease among the worms varies from field to field. In some 
fields, as high as 50 to 50 percent of the worms were affected. This should help 
reduce the threat of serious damage to late -maturing soybeans from the next gen- 
eration of green cloverworms. In addition, many of the larger worms are nearly 
through feeding, and some have already pupated. 

In most areas, populations are generally somewhat lower than they were a week 
ago; thus, fewer fields will require treatment. However, the situation still 
bears watching; the population of worms is still high in some fields. 

Damage from these pests is most likely to occur from the late-blossom through the 
pod -development stage, when leaf destruction may result in decreased yields. 
Plants can usually stand losses of 25 percent or more of the leaf surface, even 
at this critical time. Therefore, do not worry about controlling these worms 
until about 25 percent of the leaf surface has been consumed and until, by several 
counts, you find 6 or more worms per foot of row. When the pods approach the 
filled stage, leaf loss is of much less importance; if late enough, this can be 
beneficial. 

Reports indicate that 1-1/2 to 2 pounds of toxaphene per acre has not performed 
consistently well. Carbaryl, by report, has provided good control, but should 
not be used at more than 1 pound per acre, because high rates will damage beans. 
Malathion at 1 pound per acre has given good results in the few fields where it 
has been used. It has a shorter residual life than toxaphene and may not kill 
newly hatching worms more than a day or two after application. 

Toxaphene may be used with greater bee safety than carbaryl or malathion. If bee 
yards are present in the vicinity, either use toxaphene or malathion. If you are 
using malathion, apply in the late afternoon, after bee activity has ceased. 

Potato leafhoppers and plant bugs are also abundant in soybean fields. As you 
control cloverworms, you control these pests --adding to the benefit to yield. 



-3- 

Bee Poisoning (taken from the Cornell University Chemicals Pesticides Newsletter) 

Bees are an essential part of our agriculture. Most bee poisoning occurs when 
pesticides are applied to crops while in bloom. However, some fields, though not 
in bloom, will have weeds in bloom and selection of the safest materials available 
should be made to keep poisoning to a minimum. Spraying in the evening or early 
morning will help. 

Other hazards are: 

1. Drift of toxic sprays or dusts on to adjoining crops which are in bloom 

2. Contamination of flowering cover crops when orchards are sprayed 

3. Bees coming into contact with insecticide residues on plants 

4. Bees drinking or touching contaminated water on foliage or flowers 

5. Bees collecting contaminated pollen or nectar 

6. Bees collecting insecticidal dusts with pollen (arsenical materials and Sevin 
are especially dangerous because they may be stored with pollen in the hive 
and later fed to brood; hazardous amounts of insecticides have not been found 
in honey) 

Cooperation between the beekeeper and the grower should be a major consideration 
in reducing bee poisoning. Try to work together to reduce the chances of poison- 
ing. Remember that foraging bees may travel 1 or 1-1/2 miles. Do your part to 
reduce bee poisoning. 

University of Illinois Circular 940, Pesticides and Honey Bees, is available at 
your Extension adviser's office. 

HOMEOWNER INSECTS 

Fall webworms are defoliating certain trees- -especially birch, ash, and elm. 
These pale-green or yellow worms (with a dark stripe down the back and a yellow 
stripe along each side) spin a web over the ends of the branches and skeletonize 
the leaves inside. They continue to extend the web to take in fresh foliage. 
The damaged leaves curl, turn brown, and dry up. 

A spray of carbaryl (Sevin) , using 2 tablespoons of the 50-percent wettable 
powder per gallon of water, is effective. 

Aphids are heavy on many kinds of trees, shrubs, and flowers. These small, soft- 
bodied, sucking insects (green, yellow, black, or red) secrete a sticky material 
called "honeydew." This sugary secretion coats leaves, making them glisten. 
Cars parked beneath infested trees become covered with sticky spots. Ants are 
often numerous on aphid- infested plants, where they feed on the aphid secretions. 
White specks are usually visible on the leaves; these are the cast-off skins of 
the aphids--not eggs. Leaves of heavily infested plants will curl, yellow, and 
eventually brown. 



-4- 

For control, spray the foliage thoroughly, using 2 teaspoons of 50- to 57-percent 
malathion or a 2 5 -percent diazinon emulsion concentrate per gallon of water. Do 
not use malathion on African violets or cannaert red cedar. Do not use diazinon 
on ferns or hibiscus. 

Sod webworm moths can be seen flying over lawns at dusk. They hide in tall grass 
and shrubbery during the day. These buff -colored moths of the second generation 
have been laying eggs for the past 2 or 3 weeks. If worms are going to be a 
problem, they should be causing damage soon. Brown, irregular spots in the lawn 
are an indication of damage. These gray worms (with brown spots and dark-brown 
heads) hide in the thatch and are difficult to find. Their silken-lined tunnels, 
their droppings, and the cut pieces of grass are more apparent. 

If treatment becomes necessary, apply 2 pounds of actual carbaryl (Sevin) , 1 pound 
of actual diazinon, or 1-1/4 pounds of actual trichlorfon (Dylox) per 10,000 square 
feet. Apply the amount of insecticide suggested in at least 25 gallons of water. 
Do not water for 3 days after treatment. Granular forms of the same insecticide 
can be applied from a fertilizer spreader in place of the spray. 

Fleas often provide a not -so -welcome surprise when vacationers return home. The 
hungry horde of adult fleas have developed from eggs and larvae while the dog or 
cat were away. Flea eggs and larvae are difficult to find; they develop in rugs, 
upholstered furniture, lint deposits, beds where dogs and cats sleep, and even 
outdoors in the soil. The adult fleas emerge and spread throughout the house and 
yard in search of a warm-blooded animal. Fleas usually attack the lower parts of 
the legs on humans, leaving a series of 2, 3, and 4 punctures in a row in the skin. 

For control, treat the dog or cat with a 4-percent malathion or 5 -percent carbaryl 
(Sevin) dust. Pets serve as a walking lunch counter for fleas. In cases of 
severe infestations in homes, spray lightly over rugs, upholstered furniture, 
and other areas where fleas are present with 0.1 -percent pyrethrum or 1 -percent 
dichlorvos (DDVP) from a pressurized spray can. This will provide a quick kill 
of adult fleas. Repeat treatments may be needed, since the spray lasts for only 
a few hours. Apply the same dust material used on the dog or cat on their bedding 
or basket. Outdoors, dust or spray the infested areas with either malathion or 
carbaryl. 



PLANT DISEASES 



Corn 



Stewarts leaf blight (bacteria) of corn is present in scattered fields of dent 
corn. Infections severe enough to cause yield reduction occur most frequently 
in southern Illinois. Severely blighted fields invariably have increased amounts 
of stalk rot late in the season. 

Stewarts blight can be recognized by the long, irregular streaks in the leaves. 
At first, the streaks are light-green to yellow. Later, the tissue dies and 
turns brown. Several streaks may coalesce and kill the entire leaf. Careful 
examination of the streaks when the leaf is held to the light shows feeding in- 
juries made by flea beetles. The injury appears as fine, irregular scratches. 
The disease is spread by the flea beetle. Control is obtained by using resis- 
tant varieties. 



-5- 

Northern corn-leaf blight and southern corn-leaf blight have been found in suscep- 
tible fields this weekT Only trace amounts are present. These diseases are 
caused by fungi. Northern corn-leaf blight is characterized by elliptical lesions, 
that are typically 2 to 4 inches long by a half inch wide. Southern corn- leaf 
blight is characterized by lesions 1 inch or less in length by a quarter inch wide 
that have parallel sides. The color of lesions in both diseases is grayish green 
at first. Later as the tissue dies, they become tan. Northern corn-leaf blight 
occurs throughout Illinois. Southern corn- leaf blight is usually found in only 
the southern half of the state. 

Both diseases are effectively controlled by using resistant hybrids. 

Soybeans 

Some soybean fields in southern Illinois have plants infected with bud blight. 
This virus disease usually appears at the margin of fields, especially when the 
soybeans are planted next to clover, alfalfa, or pastures. 

Symptoms vary with the stage of development at which plants become infected. In 
young plants, the terminal bud turns brown and bends sharply downward forming a 
crook. The buds become dry and brittle. Leaves may be bronzed and the plants 
remain dwarfed. Plants infected near flowering time are somewhat dwarfed and 
produce few or no pods, or a few poorly filled pods. Infected plants usually 
remain green until killed by frost. 

Phytophthora blight is more prevalent this year than it has been for several years. 
This is probably caused by the large acreage of susceptible soybean varieties 
planted and by the ideal conditions for infection by the phytophthora fungus. 
Plants may be killed at any stage of growth. The infected plants usually turn 
yellow, the leaves wilt and droop, and the plant dies. Usually, brown lesions 
can be found on the basal part of the stem of the large dead plants. 

SEED TREATMENT OF WHEAT 

The mercury seed treatment fungicides can be used on wheat planted this fall. 
Seed treatment of wheat is recommended for the control of seedling diseases caused 
by seed and soil-borne fungi that cause stand reductions, and for the control of 
stinking smut or bunt. Mercury seed- treatment fungicides will not control loose 
smut. 

The best results have been obtained with seed that has been custom treated at 
elevators and at seed and feed houses. Satisfactory results can be obtained with 
drill box formulations of the mercury seed -treatment fungicides. The use of drill 
box mixing assures that only the seed that is planted is treated. TREATED SEED 
IS HIGHLY POISONOUS: IT MUST NOT BE USED FOR FOOD OR FEED. DO NOT PUT TREATED 
SEED IN GRAIN GOING TO MARKET. 

The new systemic fungicide, Vitavax, used for smut control in small grains, will 
not be available for use on certified or market wheat seed this year. The Uni- 
Royal Company has requested label clearance for the use of this fungicide on 
foundation and registered seed only, and at this date, they have not been granted 
a label for such use. The company expects a decision from the Food and Drug 
Administration within a week. We will keep you informed on developments. 



WEEDS 

Where Banvel-D (dicamba) was sprayed postemergence on corn, we have had several 
reports of injury to nearby soybean fields. Soybean leaves become crinkled and 
cupped, and the top leaf buds do not open and expand normally but are somewhat 
clustered. 

Corn has relatively good tolerance to Banvel-D, and this herbicide controls many 
of the same weeds as 2,4-D. One of the major differences is that Banvel-D usually 
gives better control of smartweed than does 2,4-D. 

However, considering the number of cases where injury to nearby soybeans occurs 
from Banvel-D each year, we strongly suggest that other alternatives be explored 
for smartweed control. One of the best alternatives is Atrazine. Smartweeds are 
very susceptible to Atrazine- -applied preplant, preemergence , or early postemergence. 
We have obtained excellent smartweed control on dark soils with rates of 1-1/4 
pounds or more of Atrazine 80W. 

Will yields be affected in fields now showing injury? Each field needs to be con- 
sidered individually, since the degree of injury will vary. Slight cupping and 
crinkling of the leaves does not necessarily mean that there will be a yield re- 
duction. Selecting several plants at random from both the affected and unaffected 
areas of the field and counting pods should give some indication of the serious- 
ness of the problem before harvest. A comparison of yields at harvest provides 
one of your best means of appraisal. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

Insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey. 

Plant Diseases: M.P. Britton, Department of Plant Pathology. 

Weeds: Ellery Knake, Department of Agronomy. 

Ag Communications: Del Dahl. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



*—*. "WWfc. 




County 



Local Groups 



INSECT 

SURVEY 

BULLETIN 



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College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana. Illinois 



U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



August 16, 1968 



ILLINOIS INSECT. DISEASE, AND WEED SURVEY BULLETIN NO. 23 

This is the last issue of this series for 1968. We sincerely hope these 23 issuer 
have been of help to you in the control of insect, plant disease, and weed control 
problems in your community. Next year, we will have a new masthead. If you have 
suggestions for an appropriate design, send us your ideas. We appreciate your 
help and cooperation. 

CORN INSECTS 

European corn borer is still a problem to canning companies that process sweet 
corn. As many as 100 egg masses per 100 stalks were still found this week in 
mid-season to late plantings. Adhere to insecticide schedules for such fields. 
Low populations of first-generation corn borers in early planted corn provide 
many moths. Second-generation borers could be a problem if these moths concen- 
trate their egg-laying on sweet corn; but if they also deposit eggs on late- 
planted field corn, the pressure on sweet corn will be relieved to some degree. 
Overall, we do expect a noticeable infestation of second-generation corn borers 
in late corn in many areas of Illinois. 

Corn rootworm adults can now be found readily in many cornfields throughout the 
state. The highest populations of beetles are still in the west, northwest, and 
northeast sections. However, it is not uncommon to find fields of corn where 
beetle populations average up to 10 per plant in central and eastern Illinois. 

In general, it is now too late to control beetles to prevent pollination injury. 
Most fields have already pollinated. Treat late-maturing fields if there are 
5 or more beetles per ear, and if not over 50 percent of the plants have silked. 
Use 1 pound of carbaryl (Sevin) , diazinon, malathion, or 1/4 pound of methyl 
parathion per acre. Methyl parathion should be applied by experienced applicators 
only . Allow 5 days between treatment and harvest for malathion, 10 days for 
diazinon, and 12 days for methyl parathion. Diazinon will control corn leaf 
aphids, while carbaryl will not. 

Do not expect a single insecticide application for adult control to significantly 
reduce the number of larvae that will be present in the field next year. Migra- 
tion of the adult beetles from adjacent fields and prolonged emergence will pro- 
vide sufficient eggs to cause economic problems in 1969, if the field is planted 
to corn again. However, it is possible that two or more applications ma)' kill 
enough adults now to reduce the number of larvae next year. A random survey of 
cornfields is now underway in 22 counties- -checking adult beetle populations, in 
order to better estimate possible damage in 1969. 



For the next 4 weeks, examine silks and plants every week for the green, northern 
corn-rootworm beetles or the striped, western corn-rootworm beetles. You are 
most likely to find western rootworm beetles already in second-year cornfields, 
where they will lay eggs for next year's crop of rootworms. Northern rootworm 
beetles will be most common in fields where corn has been grown for two or more 
years successively. They will also migrate, and will occasionally be found this 
fall in fairly large numbers in first-year cornfields. 

If you find no beetles, it is unlikely that you will have rootworm problems next 
year. If you find beetles, this does not necessarily mean you will have rootworm 
problems next year, but the odds are that you will. Egg laying is underway right 
now . 

How many beetles should you find to predict problems next year? We do not know; 
but 1 per plant is a start, and 5 per plant can lead to serious problems. If 
you find this many, plan on using one of the phosphate or carbamate insecticides, 
because all rootworms in Illinois can now be considered resistant to aldrin or 
heptachlor. 

If the western corn rootworms have not been reported from your county, please 
send suspicious -looking beetles to us. See your Extension adviser in agriculture 
for a list of counties where this pest has already been found. The western corn 
rootworm was found for the first time in Mason and Logan counties this week. 

Corn leaf aphids are about as conspicuous now by their absence as they were by 
their presence a few weeks ago. Winged aphids have been migrating from infested 
fields as soon as they reached the dry-silk stage. Huge numbers of these winged 
aphids have infested the whorls of late corn, where some build-up of wingless 
offspring may occur. In general, however, the aphid problem is disappearing. 

Fall armyworms are appearing in very late-planted corn that is just now in the 
whorl or very- early- tassel stage. These grey to brown worms can be found deep 
in the whorl. As the partially damaged leaves emerge, they are very ragged. 

Damage is most common in patches or areas in the field; the female moth will 
deposit a cluster of several dozen eggs on one leaf. As they hatch, the tiny 
worms migrate or are blown onto adjacent plants- -thus affecting several plants 
in the one spot. 

Usually, yields are not seriously affected. Sometimes, however, these worms enter 
the ear and stalk. They are damaging if they feed extensively in ears. Although 
this is usually not the case, it can occur. 

Control is difficult, since the worms are either deep in the whorl or in the ear 
before they are discovered. Carbaryl (Sevin) or toxaphene granules will help 
control them in the whorls; carbaryl sprays will help prevent ear infestations, 
but will not control the worms after they are deep in the ear. 

SOYBEAN INSECTS 

Green cloverworm populations continue to decline. The fungus disease that has 
killed them apparently is now widespread in the state, and the worms have 
disappeared rapidly. Beans should soon mature enough that reinfestation would 
not seriously affect yields. 



-3- 

Leafhoppers disappeared almost as rapidly as the cloverworms. They are very 
scarce now, even though they were quite abundant in soybean fields a few weeks 
ago. 

Grasshoppers are abundant in some roadsides, ditches, fencerows, and grass water- 
ways. In some instances, they have started to migrate into stands of corn, soy- 
beans, and hay. If large numbers have been observed and are causing damage 
(especially to soybean pods) , they can be controlled with 3/4 pound of carbaryl 
(Sevin) or 1-1/2 pounds of toxaphene per acre. This would apply to cornfields, 
soybean fields, and fencerows. In clover and alfalfa fields, use either 5/4 
pound of carbaryl, 1/2 pound of diazinon, 1 pound of malathion, or 5/4 pound of 
naled (Dibrom) per acre. 

Do not feed soybean forage treated with toxaphene to dairy animals, or to live- 
stock fattening for slaughter. Do not make more than two applications after pods 
begin to form. 

Treat while the 'hoppers are small and before damage is severe. 

WHEAT INSECTS 

Hessian fly populations are at the lowest level in 10 years, but they could build 
up rapidly if the weather and farm practices during the next year favor their 
survival. To keep this pest at its present low level, destroy all volunteer 
wheat by mid-September. In this way, the adult flies that emerge in late Septem- 
ber or early October will have no wheat on which to deposit eggs. Also, seed a 
resistant variety of wheat.. Soft wheats (such as Knox 62 and Benhur) or hard 
wheat (such as Gage, Scout, Scout 66, and Parker) are suggested by the university 
of Illinois Agronomy Department as resistant varieties. 

If you seed a Hessian fly -susceptible wheat, observe the date recommended for 
optimum yields for your community. Even when seeding a resistant variety, it is 
best to observe the "fly-free" dates. 

HOMEOWNER INSECTS 

Crickets often migrate consideraDle distances at this time of year. They feed 
on vegetation in uncultivated areas during the summer. Ordinarily, their food 
supply (in pastures, fencerows, ditch banks, and other grassy areas) dries up 
in late August or early September. This food shortage --added to their instinc- 
tive desire to migrate-- results in huge swarms, often suddenly appearing around 
lights at night. A chlordane spray around the house foundation, the doorways, 
and the outdoor lights of the home will help reduce the number of these invaders 
that get into the house. 

Leafhoppers (wedge-shaped, ' sects about 1/4 ppeai 

in great numbers around lights. As with crickets, these insects have been develop- 
ing all summer; as they mature and their food dries up, they have the urge to 
migrate. Chlordane sprays will also be helpful here. 

Foundation sprays of 1 -percent i1 i ill 3 p t control the leaf- 

hoppers and crickets, as well as ants, spiders, and roac ting 

into homes this fall. Use emulsifiable concentrate, and dilute with water to a 
1-percent strength. Spray the foundation of the house to runoff, as well as a 
4-inch strip of soil alongside the foundation. Spray around doorways and lights. 
If you plan to spray only the house foundation, use a 2-percent chlordane solution. 



If millipedes (thousand- legged pests) are a problem, use carbaiyl (Sevin) around 
the foundation and out into the yard for several feet. 

PLANT DISEASES 

Reportedly, the Vitavax label for the treatment of foundation and registered 
barley and wheat seed has been approved and is effective for use this week. 
Official confirmation is expected shortly. 

WEEDS 

This has been a bad weed year; the weather has favored the weeds. Despite this 
handicap, weed control has been very good. The first killing frost is just 
around the corner, and it will kill the weeds that were missed this summer. But 
they have shed seeds for a next year's crop. Watch during harvest for the weedy 
spots. This will indicate where and what to expect next year. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 



It has been a privilege of the following people to prepare these weekly reports: 

Insects: H.B. Petty, Steve Moore. Roscoe Randell, Don Kuhlman, and Stephen 
Sturgeon, University of Illinois College of Agriculture and Illinois Natural 
History Survey; and E.R. Jaycox, Department of Horticulture. 

Plant Diseases: M.P. Britton and M.C. Shurtleff . Department of Plant Pathology, 
University of Illinois College of Agriculture; and Donald Schoeneweiss and J.L. 
Forsberg, Illinois Natural History Survey. 

Weeds: Ellery Knake and Marshal McGlamery, Department of Agronomy; H.J. Hopen 
and J.D. Butler, Department of Horticulture, University of Illinois College of 
Agriculture; and Robert Hiltibran, Illinois Natural History Survey. 

Equipment : J.C. Siemens, Department of Agricultural Engineering. 

Ag Communications: Del Dahl. 

The information for these re-ports was gathered by these people, other staff mem- 
bers s county Extension advisers, USDA Agricultural Research Service^ Plant Pest 
Control Branch personnel- and other cooperators. 




INSECT 

SURVEY 

BULLETIN 



*/ry of ^ 



County 



Local Groups 



College of Agriculture 

University of Illinois 

and Natural History Survey, Urbana, Illinois 



U. S. Department of Agriculture Cooperating 



FOR IMMEDIATE RELEASE 



November, 1968 



Illinois Insect, Disease, and Weed Survey Bulletin No. 24 



SPECIAL ISSUE 



INSECTICIDE RECOMMENDATIONS 






\X 






.r\f*C 



We receive many inquiries about changes in recommendations during the fall of each 
year, but prior to the publication of printed circulars. We are sending you these 
Tentative Special Suggestions and Major Changes for 1969 to help answer your "early" 
questions. Caution statements , time limitations between application and harvest, 
and other precautions are not included. These tentative suggestions will appear 
in final form in the University of Illinois College of Agriculture Circular 899, 
which will be sent to the printers by November 25, 1968. These statements have 
been reviewed by entomologists of the Illinois Natural History Survey and the Uni- 
versity of Illinois College of Agriculture, and were prepared by H.B. Petty, Steve 
Moore, Roscoe Randell, and Don Kuhlman from information gathered by entomologists 
in Illinois and the USDA Agricultural Research Service. 

Dairy Farms 

As in the past, dairy farmers are cautioned against the use of the chlorinated 
hydrocarbon insecticides --aldrin, chlordane, dieldrin, DDT, endrin, heptachlor, 
or lindane--to avoid the possibility of illegal residues in milk. 

Because of possible drift, do not apply sprays or dusts of aldrin, DDT, chlordane, 
dieldrin, heptachlor, or lindane to fields adjacent to dairy- hay, pasture, or 
ensilage crops. 

Soybean Farms 

On the basis of research and the results of random surveys of Illinois soybeans, 
we suggest to Illinois soybean producers the following limitations on the use of 
certain insecticides in 1969: 

1. Do not use the soil insecticides aldrin, chlordane, dieldrin, endrin, heptachlor, 
or lindane as a soil or foliar treatment for soybeans. 

2. At present, if either aldrin or heptachlor have been applied annually in a 
field for 5 or more years, allow 2 years to elapse from the date of the last 
application before planting soybeans. Thus, if aldrin or heptachlor was ap- 
plied to a field from 1964 through 1968, do not apply aldrin or heptachlor in 
1969; do not grow soybeans in this field until 1970. If corn is grown, use one 
of the suggestions for rootworms listed on page 2. 



3. For the common Illinois rotation (which includes soybeans, corn, and grains), 
continue to plant soybeans as you have in the past. The future of this sug- 
gestion depends on research and survey data. 

CORN SOIL INSECT SITUATION 

Western corn rootworms : In 1968 they were found, with the exception of 8 counties, 
throughout the area of Illinois north of a line from Pittsfield (Pike County) , to 
Lincoln (Logan County) , to Kankakee (Kankakee County) . In 1969 , they may spread 
to most of the counties north of a line from St. Louis to Danville. In Mercer and 
adjoining counties, many second-year cornfields were damaged in 1968; in 1969, 
many fields of second-year corn will be severely damaged in the area north and 
west of a line from Dixon to Peoria to Stronghurst (Highway 116) , and extended to 
the state boundaries. Second-year cornfields will be damaged more than others, 
but not all of them will be severely affected. 

All western corn rootworms in Illinois are resistant to the commonly used soil 
insecticides aldrin and heptachlor; they will no longer control this insect. 

The northern corn rootworm , although found throughout Illinois, is most abundant 
north of Highway 56 (Pittsfield to Springfield to Decatur) , and is often a pest 
in fields if corn is grown for 3 or more years continuously in the same field. 
Under some conditions, we have seen second-year corn damaged by northern corn 
rootworms. Although it is not common, this does occur. 

Even though northern rootworms are not a general pest south of this line (Pitts- 
field to Springfield to Decatur) , they do damage corn severely in central localized 
areas, such as bottomland, where corn is grown as a continuous crop. 

Northern corn rootworm populations increased in 1968. Despite this, weather con- 
ditions favored root regrowth, and many fields were able to recuperate from severe 
root pruning and produce a good yield. Therefore, damage was less apparent in 
1968 than in 1967. The population of corn rootworm beetles was greater in August, 

1968, than in either 1966 or 1967. Thus, the threat of damage is greater for 

1969. To further complicate matters for 1969, resistance to aldrin and heptachlor 
has increased to such a degree that these two insecticides no longer give practical 
control of northern corn rootworms in the majority of cornfields. 

Seed-corn beetles eat the seed and chew off the sprout during germination. There 
were a lot of these pests this past year. Quite often, aldrin, dieldrin, heptachlor, 
and lindane soil or seed treatments failed to control them. Seed-corn maggots 
hollow the seeds prior to their germination. In at least two instances, resistance 
to aldrin, chlordane, dieldrin, heptachlor, and lindane were confirmed. 

In 1968, attacks by these two seed pests reduced stands from a few hundred plants 
per acre in some fields to as many as several thousand plants per acre in others. 

Wireworms , cutworms, white grubs , grape colaspis , and others are still controlled 
by the use of aldrin or heptachlor, even though these chemicals can no longer be 
relied on to control rootworms, seed-corn beetles, and seed-corn maggots. 

CONTROL OF RESISTANT ROOTWORMS, RESISTANT SEED INSECTS, AND GARDEN SYMPHYLANS 

A crop rotation may be the easiest method for controlling resistant corn rootworms. 
To hold populations of northern corn rootworms at low levels, do not grow corn for 
more than 2 years successively in any rotation. In western corn rootworm areas, 



-3- 

rotations involving only 1 year of corn may be required. However, the resistant 
strain of northern corn rootworms may become a problem on second-year corn, much 
as the western corn rootworms are now. 

In addition to crop rotation, early planting may help minimize root damage by 
corn rootworm larvae and pollination damage by the adults. However, early plant- 
ing may increase corn borer problems . 

Although several insecticides are labeled for corn rootworm control entomologists 
of the University of Illinois Cooperative Extension Service and the Illinois Natu- 
ral History Survey suggest the following materials for the most-effective control 
of rootworm in Illinois. These rates are based on row length, not width. 

For Planting Application 

Furadan (if label approval is granted) 1 pound per acre 

Buxten 1 pound per acre 

Dasanit 1 pound per acre 

Dyfonate 1 pound per acre 

Phorate 1 pound per acre 

These materials were used in Illinois in 1968 at the rates shown. To reduce 
costs, lower rates of application have been suggested. Lower rates will likely 
reduce effectiveness, particularly with heavy infestations. 

For Basal Application in June 

Diazinon 1 pound per acre 

Disulfoton 1 pound per acre 

Parathion 1 pound per acre 

Phorate 1 pound per acre 

Carbaryl 2 pounds per acre 

Many of the registered organic -phosphate insecticides- -and carbamate insecticides 
when applied at planting time --kill only 40 to 75 percent of the rootworms. With 
light infestations of corn rootworms, this provides practical control; although 
not as effective on early planted corn as on that planted later, they still did 
an acceptable job in Illinois during 1968. However, in fields with moderate-to- 
heavy infestations, the more -effective insecticides are needed to give a practical 
degree of control. 

Applications of insecticides approved for use during cultivation in late May to 
mid- June are equally effective. The insecticide is directed at the base of the 
plant; for best results, there should be some soil cover. These basal applica- 
tions can be made when convenient. But to avoid bad weather, do not wait until 
the last minute. 

The insecticides listed for rootworm control at planting may be adversely affected 
by heavy rainfall. The control of corn rootworm may be less effective when these 
insecticides are applied to early rather than later-planted corn, because of ex- 
posure to greater amounts of rainfall. 

Extreme drought conditions may also decrease the effectiveness of the insecticide. 
This could be particularly important in the use of basal applications to control 
rootworms. For this reason, late May to mid- June applications are encouraged, in 
order to take advantage of normal rainfall patterns. 



-4- 

Resistant seed-corn beetles and maggots were controlled by planting applications 
of Dasanit, diazinon, dyfonate , Furadan, and phorate. We have no data on seed- 
beetle control by the use of planter applications of carbaryl, disulfoton, and 
parathion. 

In a few fields in central Illinois, an experimental application of 3 ounces of 
50-percent diazinon wettable powder plus 1-1/2 ounces of graphite per bushel of 
seed just prior to planting gave excellent seed-corn beetle control. Resistant 
seed-corn maggots have been controlled with as little as 1/2 ounce of diazinon 
per bushel of seed in Canada. The rate of diazinon to be used per bushel of 
seed has not been thoroughly established for seed-corn beetle and seed-corn maggot 
control in Illinois. It is possible that i ounce per bushel of the actual diazinon 
may provide excellent control. 

If combinations of diazinon and other insecticides are used as seed treatments, 
follow the manufacturer's directions to avoid possible germination injury. In 
using a seed treatment, empty and clean the planter often. This will avoid any 
accumulation of excess powder in the bottom of the planter box, which could inter- 
fere with seeding rates. 

To further confuse the soil-insect problem in Illinois cornfields, the garden 
symphylan (a tiny, white, rapidly-moving, centipede -like pest) appeared in many 
Illinois cornfields. It feeds on corn roots. Small areas in a field may be 
generally stunted, or one plant may be knee-high while an adjoining plant may be 
shoulder-high. These stunted plants do not produce normally. Of the insecticides 
mentioned for rootworm control, only dyfonate seems to be effective in controlling 
this pest. Effective control using zinophos and parathion has been reported by 
some states. 

CONDENSED SOIL INSECTICIDE SUGGESTED USES 

In 1969, suggestions for maximum soil-insect control in Illinois cornfields must 
be based on individual situations. We have attempted to list them below: 

1. First-year corn, or any corn in areas where rootworms are no problem: 

On nondairy farms : 

Use diazinon as a seed treatment to control resistant seed-corn beetles and 
seed-corn maggots. If cutworms, wireworms, white grubs, grape colaspis, and 
others are usually a problem, broadcast and disk-in 1-1/2 pounds of aldrin or 
heptachlor per acre prior to planting. Row treatments of 1 pound per acre can 
be used, but will be less effective. 

On dairv farms : 

i. 

If soil insects have been a problem, apply 1 to 1-1/2 pounds of diazinon, or 
1 pound of Dasanit, dyfonate, or phorate at planting time in a 7-inch band to 
the surface of the soil ahead of the press wheel. If you do not do this, at 
least as a minimum, use a diazinon seed-treatment. If you suspect that garden 
symphylans are present, use dyfonate at planting time. 



-5- 

2. Fields that have been in corn for 2 or more years in an area of severe western 
corn rootworm infestation (west and north of a line from Dixon to Peoria to 
Stronghurst) : 

Use Furadan, Buxten, Dasanit, dyfonate, or phorate at 1 pound per acre at 
planting time, or apply 1 pound of diazinon, disulfoton, parathion, phorate, 
or carbaryl as a basal application. When using Buxten at planting time or 
any basal application with no planting-time application, use a diazinon seed- 
treatment at planting time. 

5. Fields in corn for 5 or more years in the area where western rootworms are 
not a problem but where northern corn rootworms are a problem: Apply the 
same controls listed in No. 2. 

SOYBEAN INSECTICIDE SUGGESTIONS 

Green cloverworm : We will tentatively drop toxaphene and add malathion at 1 pound 
per acre . 

Caution : Carbaryl used at more than 1 pound per acre has injured soybeans. 

SUGGESTED INSECTICIDE CHANGES FOE INSECT CONTROL ON LIVESTOCK 
AND IN LIVESTOCK BARNS FOR 1969 

Additions to Current Suggestions 

1. Ciodrin (1.0-percent water, 1 pint per animal per week) for face flies on 
pastured beef and dairy cattle. 

2. Ruelene (crufomate) emulsion, 2 cc. per 10 pounds of body weight, as a 
drench for sheep -nose bot control. 

5. Toxaphene (0.5-percent water base) for mange control on beef cattle and 
swine . 

4. Ciodrin for mange control on dairy cattle. 

5. Rabon (SD 8447) as a residual barn spray for house flies. 
Deletions to Current Suggestions 

1. Rotenone for cattle -lice control on dairy cattle. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




MSEC! WEED & PLANT DISEASE SURVEY BULLETIN 

<\TE/COUNTY/LOCAL GROUPS/US. DEPARTMEMT OF AGRICULTURE COOPERATING"»*(ft^U \ W» *&"'"' 



c 



)R IMMEDIATE RELEASE 



No. 1, March 28, 1969 



lis series of weekly bulletins provides a general look at the insect, weed, and plant 
■sease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
*eviated control measures. Each individual should check his own fields to determine 
>cal conditions. 



INSECTS 



irage Insects 



falfa weevil development slowed this week due to the cold, wet weather. An average of 
i larvae per square foot were found in the extreme southern counties. The worms are still 
lall, more yellowish than green, and hidden in terminal leaf buds. Some tips are showing 
ceding but no damage has yet occurred. A week to ten days of warm weather would cause a 
idden hatch of many new larvae, resulting in the need for treatment in some fields. The 
.rst insecticide applications will probably not be needed in the extreme southern counties 
Ltil the week of April 6 or later, depending on the weather. Cool weather will prolong 
,g laying and hatch, allow the alfalfa to grow, and lessen the amount of injury. 

lis spring, the alfalfa weevil has the potential of inflicting severe damage to fields of 
.falfa south of a line from Watseka to Hardin. Damage could be noticeable. Some treat - 
aits could be needed in alfalfa fields in the area north of this line as well. 

: you intend to protect your alfalfa from weevil attack, begin to make preparations now. 
an to apply an insecticide when 25 percent of the terminals show noticeable feeding and 
irvae are still present. A second application may be needed about 2 or 3 weeks later as 
>re larvae hatch. Even a third spraying might be needed in some southern areas to com- 
.etely protect the first cutting and new growth of the second cutting. 

le insecticide recommendations are : 



Experienced commercial applicators who have the proper protective clothing will get 
the best results with methyl parathion applied at 1/2 pound per acre, or a special 
alfalfa weevil spray of azinphosmethyl (Guthion) at 1/2 pound per acre. Azinphos - 
methyl can be applied only once per cutting . Do not harvest for 15 days after treat - 
ment with methyl parathion, 16 days for azinphosmethyl . 

The person not properly equipped with protective clothing to use methyl parathion or 
azinphosmethyl can use a mixture of 5/4 pound of malathion and 5/4 pound of methoxy- 
chlor per acre (5 pints of a concentrate containing 2 pounds of methoxychlor and 2 
pounds of malathion per gallon) , or a mixture containing at least 1/2 pound of diazinon 
and 1 pound of methoxychlor per acre (2-1/2 to 3 quarts of the commercially prepared 
mixture Alfatox) . You may also use 1-1/4 pounds of malathion per acre (1 quart of the 
5-pounds-per-gallon concentrate) in the morning on days when the air temperature will 
be above 60° F. Do not harvest for 7 days after treatment with methoxychlor, diazinon, 
or mixtures of them. There is no waiting period for malathion. 



-2- 

The quantity of finished spray applied per acre is also important. Use no less than 4 
gallons per acre by air or 20 gallons per acre by ground machine. 

Clover- leaf weevil larvae, which can be confused with alfalfa weevil, are also present in 
both alfalfa and clover fields. Clover-leaf weevils are large, pale-green larvae with 
white stripes down their back and a tan or brown head; the alfalfa weevil has a black 
head. Clover-leaf weevils feed mainly at night, hiding down around the base of the plant 
during the day; alfalfa weevils are found feeding in the terminals during the day. Warm, 
humid weather enhances the spread of a fungus disease that kills clover-leaf weevils. 
Parasites also help control them. Clover and alfalfa stands can usually grow away from 
the damage; however, if damage becomes severe and growth is slow, a spray of 1 pound of 
malathion per acre is effective. This will also control pea aphids, a few of which are 
now present in southern sections . 

CORN INSECTS 

European corn borer survival this past winter was normal or above in the northern, western 
and west -southwestern sections of the state, as shown by a recent survey. A similar surve 
will be conducted in other areas within the next few weeks. The following survival record 
were obtained: 

Percent survival 
County of corn borer 

Greene 82 

Henderson 76 

JoDaviess 76 

Knox 62 

LaSalle 76 

Livingston 88 

Macoupin 84 

Madison 68 

Winnebago 80 

Average 77 



A figure of 70 to 80 percent is considered a normal survival level--above 80 is high, and 
under 70 is below normal. Statewide, the borer population is higher than it has been 
since 1955, and it presents a potentially serious problem. The incidence of parasites 
and diseases among borers is low, so borers are healthy. However, strong winds or beating 
rains in late May (southern sections) and June (central and northern sections) , when the 
overwintering moths are emerging, could still eliminate much of the problem. 

Plow cornstalks cleanly and you will eliminate 99 percent of the overwintering borers. 
Stalk choppers or shredders should be used on stalk fields that are not plowed, or else 
disk them thoroughly. This will eliminate about 92 percent of the overwintering borers. 

Plant hybrids that are adapted to your area. If you plant your corn early, plan on ap- 
plying an insecticide to prevent com borer damage. Midseason plantings of corn will 
have less injury from both first- and second-generation corn borer. 

HOMEOWNER INSECTS 

Scale insects are present on many kinds of trees and shrubs- -lilac, dogwood, Euonymus, 
tulip, spruce, elm, etc. The scales are in the egg stage beneath the old body-covering 
of the female scale. Examine the branches of trees and shrubs in your yard for the pres- 
ence of scales. 






A dormant oil spray will help control San Jose, Putnam, and tulip tree scales and over- 
wintering red mite eggs. Purchase a dormant oil and mix it with water, according to 
manufacturers' directions on the label. Do not apply when temperatures are below 40° F. 
or if new growth is present. Do not use on evergreens. For later treatments to control 
scales, apply a malathion water-base spray. Time the treatments at peak hatch when the 
scales are in the crawler stage. This will vary with the type of scale and the location 
in the state . 

Spring cankerworms , dark-brown to dark-green measuring worms, will be feeding soon on trees 
like American elm and apple as well as other fruit and shade trees. They attack early, 
feeding on developing leaf buds and newly developing leaves. Sometimes they completely 
strip a tree of foliage while other trees are only partly defoliated. When full-grown, 
the worms drop to the ground by means of silken threads that appear like streamers in the 
wind. By this time, it is usually too late for control. 

Use either carbaryl (Sevin) with 2 pounds of 50-percent wettable powder or lead arsenate 
with 4 pounds in 100 gallons of water. 

You can control soil insects in your vegetable garden by applying diazinon at 1 ounce per 

1,000 square feet before planting. To do this, mix 1/4-pint (4 fluid ounces) of 25 -percent 

diazinon liquid concentrate in enough water (usually 2 to 3 gallons) to cover 1,000 square 
feet, then rake into the soil. 

Flies are becoming a nuisance again in many homes. These are mainly cluster flies, but 
face flies, flesh flies, and bottle flies are also present. They have overwintered in the 
partitions and other recesses within the home. On warm, sunny days they become active. 
Those that are unable to get outdoors end up indoors, usually congregating around windows. 

The best control is provided by using 20-percent dichlorvos (DDVP) resin strips. Place 
these strips in attics, basements, and other fly- infested rooms. One strip per 1,000 
cubic feet (about one per average -size room) is effective for about 6 weeks. As an 
added precaution, hang the strips out-of -reach of children and away from fish bowls or 
food counters. An 0.1 -percent pyre thrum or 0.5 -percent dichlorvos (DDVP) space spray, 
applied from a pressurized spray can, can be used for quick knockdown in place of the 
dichlorvos resin strips. Apply for 15 to 20 seconds in an average-size room. Frequent 
treatments will be needed during problem periods. Remove all birds, fish, and other pets 
before making the application. 

WEEDS 
Treat Musk Thistle In April 

Several areas of Illinois have a new weed called "musk" or "nodding thistle." The thistle 
thrives in pasture land and other noncultivated areas . 

Musk thistle is a biennial, requiring two years from seedling to seed. The first year, 
a basal rosette of coarsely lobed, spiny leaves forms. During the second year, the 
flower and seed head develop. Infestations may not be noticed until the second year; it 
is then that the plants produce their tall, upright flower stalks- -usually during May. 
Unfortunately, it is too late for the most effective control by that time. 

April is the best time to treat musk thistle. The weed is still in the rosette stage, and 
the musk thistle is quite susceptible to 2,4-D. But, the plant builds up a tolerance to 
2,4-D after the flower stalk forms. Also, control is usually better when the temperature 
is above 75° F. and when the plant is growing actively. 



Apply 2,4-D at the rate of 1 to 1-1/2 quarts per acre of the 4-pounds-per-gallon formula- 
tion in 20 or more gallons of water. Use the low-volatile ester form. Remember that 
April treatments are much more effective than later treatments. Do not graze dairy cattle 
for seven days after the 2,4-D treatment. 

For spot treatments, put 1 quart of the same 2,4-D mixture in 25 gallons of water and spray 
until the plant is moist. Adding one cup of household detergent to the 25 gallons of watei 
will increase the effectiveness. 

NEW NAMES FOR HERBICIDES 

This season has brought several name changes to herbicide users . To help limit some of 
the confusion, here they are: 

1. "Swat" is the new name for the Sutan-atrazine combination. 

2. Geigy's new names for atrazine and simazine are "Aatrex" and "Princep." 

3. Alanap + CIPC has these new names: Whistle (Kaiser); Amoco Soybean Herbicide (Americar 
Oil) ; and Alanap Plus (Uniroyal) . 



PLANT DISEASES 



Oat Seed Treatment 



Proper treatment with a mercury fungicide (such as Ceresan, Chipcote , Ortho LM, or Panogen 
is cheap insurance for improving stands and grain quality, and also for getting higher 
yields. Income from oats can be increased as much as $5 per acre with a seed treatment 
that costs only a few pennies. Oat diseases controlled by mercury seed treatment include 
loose and covered smuts, bacterial blights, Helminthosporium leaf blotch, scab, seed-borne 
root rots, Fusarium blight, seed decay, and seedling blights. New races of the smut fungi 
are causing more loose and covered smuts both in Illinois. 

■ 
It is difficult for many farmers to get oat seed treated commercially. Two products are 
now available for safe and effective hopper- or drill-box treatments. T hese are Ceresan 
M-DB and Panogen PX. Follow the manufacturer's directions carefully. Warning: Treated 
seed should not be used for feed or food. Even one kernel may cause an entire carload to 
be condemned and destroyed . For more details, ask your Extension adviser for Report on 
Plant Diseases, No. 1001 (Revised) . 

Pruning — Disease Control and Tool Disinfectants 

It's pruning time. Orchardists, nurserymen, arborists, and homeowners are pruning for at 
least one of these reasons: to improve shape and form; to make spraying and dusting 
easier; to increase fruit quality and yield; to eliminate rubbing, dead, weak, and over- 
crowded branches ; or to control disease . 

When cankers, fire blight, wood decay, crown gall, or other infectious diseases are known 
or suspected, pruning tools should be disinfected between cuts or between trees. Cheap 
disinfectants you can use to dip or swab pruning tools include 70- or 95 -percent rubbing 
alcohol and liquid household bleach (Clorox, Purex, Sunny Sol), diluted 1 to 5 with water 
After using bleach, the tools should be thoroughly washed with water. 



Tree wounds more than 1 to 2 inches in diameter should be promptly covered with a 
permanent -type wound dressing or pruning paint, to prevent the entry of disease -causing 
organisms. 

USE DISEASE-RESISTANT , CERTIFIED SEED 

When ordering field crop, vegetable, flower, or other seed, select adapted varieties and 
cultivars recommended for your area that are both disease-resistant and certified. You 
can get information on field crops from the Department of Agronomy and the Illinois Crop 
Improvement Association in Urbana. By checking through seed and nursery catalogs and 
various Cooperative Extension Service circulars and other printed matter, you can find 
what you want to know about vegetable, flower, and other types of seed. 

Many improved varieties are resistant to one or more diseases. One way to get disease-free 
seed is to insist on certified seed. You can't tell by looking at a seed whether it's in- 
fected. The disease -producing organisms may be dormant or microscopic. They are often 
located under the seed coat . 

Most certified vegetable seed, and much of our flower seed, is produced under strict 
growing conditions in arid regions in the Pacific Northwest. You may pay a little more 
for certified seed, but you won't be taking the chance of increasing losses from seed- 
borne diseases. 

LAWN RENOVATION AND DISEASE CONTROL 

If your lawn is thick with a heavy mat or thatch of dead, choking grass, and if the grass 
is beginning to green-up, this is a good time to renovate the lawn and reduce future 
disease problems. "Vertical" mowers or dethatching machines are available from most 
garden-supply and rental -equipment centers. It is not unusual to remove two or more truck- 
loads of dead grass from an established home lawn. Removal helps the grass to grow and re- 
duces future losses from leaf spot and melting -out, Rhizoctonia brown patch, Schlerotinia 
dollar spot, Fusarium blight, and snow molds. Removing the clippings, especially if they 
are long, also reduces disease losses. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Rosaoe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural His- 
tory Survey. 

PLANT DISEASES: MX. Shurtleff, Department of Plant Pathology 

WEEDS: Marshal MoGlamery , Department of Agronomy 

AG COMMUNICATIONS: Del Dahl 

The information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 



Special Note to Pesticide Dealers and Applicators : The first of a series of field training 
meetings will be held for pesticide dealers and applicators on Wednesday, April 2, in 
Johnson County. We will meet at Mr. Bob Wetherell's office (Johnson County Extension Ad- 
viser), 19 Court Street, Vienna, Illinois, at 1:30 p.m. and go to the field for about 2 
hours. These meetings are to help you brush-up on trouble -shooting techniques concerning 
insect and plant-disease problems. The insect portion of the meeting will cover alfalfa 
weevil, clover- leaf weevil, pea aphids, and corn-borer development. In case of rain, we'll 
have specimens along and will meet in the Extension adviser's office. The following week 
on Tuesday, April 8, a similar meeting will be held in Randolph County with Mr. Charles 
Willman, Extension Adviser, at South St. Louis and Belmont Streets, in Sparta, Illinois. 
The meeting time, again, is 1:30 p.m. Announcements about the dates and locations for 
future meetings will be carried in this bulletin. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/U S DEPARTMEMT OF AGRICULTURE COOPERATING 

RSlfBaiYQFrjIEB 



FOR IMMEDIATE RELEASE 



d; 



No. 2, April 5, 1969 



mm 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



FORAGE 



Alfalfa weevil development continues to be slow. It now appears that no insecticide treat - 
ments will be needed in extreme southern Illinois until at least the week of April 13. 
Small larvae are generally present; an average of 33 larvae and 100 eggs per square foot 
were observed again this week. Feeding by these tiny worms is hardly noticeable, but it 
will become more apparent with warmer weather. 

Further north, the hatch has been delayed and only an occasional small worm is present. 
Continued cool weather may retard weevil development but may permit the alfalfa to grow. 
This would reduce the number of sprays needed to protect the alfalfa. But as soon as 
25 percent of the terminals show feeding, apply an insecticide unless the field is to be 
harvested within a week to 10 days. 

The insecticide recommendations are : 

1. Commercial applicators can apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) with good results. Use azinphosmethyl only once per cutting. Do 
not harvest for 15 days after treatment with methyl parathion, 16 days for azinphos- 
methyl. Wear protective clothing. 

2. Persons not equipped with protective clothing can use a mixture of (1) 3/4 pound of 
malathion and 3/4 pound of methoxychlor per acre, (2) a mixture containing at least 
1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 1-1/4 pounds of 
malathion per acre on days when air temperatures will be above 60° F. for several hours 
after application. Do not harvest for 7 days after treatment with methoxychlor, diaz- 
inon, or mixtures of them. There is no waiting period for malathion. 

Clover leaf weevils resemble alfalfa weevil, but feed at night and hide in ground debris 
during the day. Inspect red clover fields that have a heavy straw or mat covering. Slow- 
growing plants may be injured by this worm. The leaves will be devoured and the plants 
will look unthrifty- -often with almost no leaves. Although warm, humid weather favors a 
disease that will kill these worms, severe problems could develop if the cool weather con- 
tinues for any extended period. 

Clover can usually grow away from the damage. If the damage becomes severe and growth is 
slow, a spray of 1 pound of malathion per acre is effective. This will also control pea 
aphids, a few of which are now present in southern sections. 



CORN 

European corn borer survival has been quite high in Illinois this winter. Several county 
Extension advisers report survival ranges of 70 to 90 percent, with the highest ones in 
northern and southern Illinois. It now appears that weather and farm practices may well 
determine the extent of the corn borer problem this summer. 

Plow corn stalks cleanly. If they are not plowed, then disk or shred the stalks thorough^ 
to provide some help in killing these overwintering borers. Plant adapted hybrids. Since 
the earlier, more-mature corn in late June and early July is most susceptible to damage by 
first-generation corn borer, farmers who plant early should be prepared to use insecticide: 
for control. 

For corn seed beetles and maggots , the extent of resistance to aldrin and heptachlor still 
poses a problem. These two pests can reduce stands as they eat out the heart of the seed 
or cut the small sprouts. We suggest that those using aldrin or heptachlor as a soil 
treatment should also use diazinon as a seed treatment. However, when using planter-box 
seed treatments , empty the planter boxes frequently to prevent buildup on the plates or th 
accumulation of excess dust in the planter boxes. Either one can reduce seeding rates. 
Use no less than 4 ounces of 25-percent or 3 ounces of 33.3-percent diazinon seed treatmen 
per bushel of seed. Two ounces of 25-percent (or less) diazinon will probably not be suf- 
ficient to control these seed pests, particularly the corn seed beetles. 

HOME GARDEN 

Soil insects : Some home gardeners still apply such insecticides as aldrin, heptachlor, 

dieldrin, or others to the garden and work it into the soil before planting. However, the 

rates they use are often dangerously high. To avoid problems, we recommend the use of 

diazinon at 1 ounce of the actual chemical to 1,000 square feet (an area 25 by 40 feet). 

This is 1/4 pint of 25-percent concentrate in enough water to cover the area. Rake it int 
the soil immediately. 

■ 



WEEDS 
FORAGE CROPS 

Eptam (EPTC) can be incorporated before planting alfalfa, lespedeza, and birdsfoot trefoil 
to control annual grasses --when the legumes are sown without a companion crop and without 
grasses in the mixture. Apply 3 pounds (a half gallon) of the herbicide and immediately 
mix to a depth of about 2 inches by disking before seeding the legume. Do not graze or 
feed treated legumes for 60 days after treatment. 

Balan can be used in a similar manner. Balan is approved for alfalfa, birdsfoot trefoil, 
red, alsike, and ladino clovers. 

2,4-DB may be used to control broadleaved weeds (wild mustard, pigweed, and lambsquarter) 
in new seedings of alfalfa, red clover, ladino clover, alsike clover, or birdsfoot trefoil- 
when seeded alone or with oats, wheat, or barley. Apply 1/2 to 1-1/2 pounds of 2,4-DB 
amine per acre or 1/2 to 3/4 pounds of ester, when the weed's are less than 3 inches high. 
No portion of a treated crop should be fed to livestock within 30 days of application. 
2,4-DB may also be used in established forages. 

Dowpon (Dalapon) has been used successfully to kill young grass seedlings in seedling 
stands of alfalfa and birdsfoot trefoil that are not seeded with small grain or grasses. 
Use 2 to 3 pounds of the commercial preparation per acre, when weed grasses have about 



leaves and legumes are 2 to 3 inches high. Forage from the treated area must not be fed 
j dairy animals or to animals being finished for slaughter. The first-year crop should 
Dt be sold commercially or shipped interstate. 

4ALL GRAINS 

reck winter wheat now to determine the need for chemical weed control. You can control 
Dst broadleaved weeds in winter wheat with 2,4-D. April is the time to do it. Wheat is 
}St tolerant to 2,4-D after it has finished tillering in the spring and before it is in 
le boot stage. 

f there is a legume underseeding , use no more than 1/4 pound of 2,4-D amine- -1/2 pint of 
4-pound-per-gallon formulation. This rate will control most troublesome weeds, except 
ild onion and garlic. 

o control wild onion and garlic, use 1/2 pound per acre of the 2,4-D ester . This rate 
ill probably destroy legume underseedings and may damage wheat, but it will reduce aerial 
ulblet formation of wild onion and garlic and will lessen the possibility of harvest-time 
ockage . 

ead the label and follow all precautions. Federal regulations specify: "Do not forage 
r graze treated grain fields for 2 weeks after treatment. Do not use treated straw for 
ivestock feed." 

OME GARDEN 

Cultivation is the most-used and safest method of weed control for the home gardener. This 
ust be done several times during the summer to be effective. Mulching is also quite effec- 
ive, because it prevents light from reaching the weed seedlings. Such opaque materials as 
raft papers, black polyethylene, ground corn cobs, weed-seed free straw, etc. are used, 
n addition, mulching conserves moisture, makes for uniform soil temperatures, and keeps 
he edible portions above ground clean. 



PLANT DISEASES 



MALL GRAINS 

outh of about Highway 50, Septoria leaf blotch has seriously infected or killed most of 
he wheat leaves formed last fall. It is now moving onto the leaves formed this spring, 
he wheat is about 8 inches tall in Johnson and surrounding counties. The dead fall leaves 
erve as a source of inoculum for the newly formed leaves. 

o rust or powdery mildew is evident now on wheat in southern Illinois. 

here is some heaving damage. No serious loss is expected, since soil moisture is abundant 
nd the injured wheat plants are starting to reroot themselves. Off-color leaves --reddish - 
urple to purple- -are common, mostly because of the unseasonably cold weather. 

■arge yellow spots are also common in many wheat fields. This may be the result of overly 
et soil and infection by Septoria. 

"or more information on Septoria Leaf Blotch and Glume Blotch of Wheat, write to the Depart - 
ent of Plant Pathology, 218 Mumford Hall, University of Illinois Urbana-Champaign Campus, 
;, rbana, Illinois 61801. Ask for a copy of RPD No. 105 (Revised). 



-4- 

CORN AND SOYBEANS 

Don't rush corn and soybean planting. Wait until the soil warms up. If you plant now, the 
seed- -even though properly treated with a protective fungicide such as captan or thiram-- 
will be in cold, wet soil, and sprouting will be delayed. This gives seed decay and pre- 
emergence seedling blight fungi, such as Pythium, a chance to "get in their licks." 

After the soil warms up, the seed will germinate more rapidly, stands will be more uniform, 
plant vigor and yields will be higher, and the possibility of having to replant will be 
greatly decreased. 

The period during which a seed germinates and the seedling becomes established is very 
critical in the life of a corn or soybean plant. Avoid deep planting, poor seedbed prepara 
tion, and cold or wet soils (below 50° to 55° F. for corn and about 60° F. for soybeans). A 
soil temperature below 50° to 55° F. favors most soil-borne fungi, causing seed rot and 
seedling blights. 



GENERAL INFORMATION 
TANK-MIXING AGRICULTURAL CHEMICALS 

There is considerable interest in mixtures and combinations of herbicides, insecticides, 
and liquid fertilizers. For use limitations on mixtures, read all labels and follow the 
one with the most-severe restrictions. 

There are both tank-mix and formulated mixtures. While Sutan-atrazine is only a tank -mix, 
other herbicide combinations (such as Ramrod -atrazine and Lorox-Ramrod) are available as 
both tank and formulated mixes. With tank mixes, you can vary the ratio to meet local con 
ditions. But there may be problems caused by inefficient agitation, insufficient water 
volume, and lack of an emulsifying agent. Normal spraying requires approximately 2 gallon 
of spray volume for each pound of wettable powder, to keep a good dispersion. 

Wettable powders (WP) require continuous agitation. Mechanical or hydraulic- jet agitation! 
is preferable to normal by-pass agitation. 



■ 



In mixing, first have some liquid carrier in the tank. Never place concentrated chemicals 
in an empty tank. Also, add wettable powders before adding emulsifiable concentrates (EC) 
spray oils, or other additives. Always premix wettable powders before adding them to the 
tank. 

Some chemicals are formulated as "fertilizer grade," with extra emulsifier. But if the 
chemicals you use are not this way, adding emulsifier can sometimes help. Compex (Colloid 
Products Corporation) is a spray tank adjuvant formulated to help in preparing chemical 
blends. Use it at the rate of 3 pints per 100 gallons of spray (1/2 teaspoon per pint). 

Check compatibility by mixing small amounts first. To do this, a set of measuring spoons 
and a few quart jars are quite handy. When checking compatibility, remember that 1 tea- 
spoonful per pint equals 1 quart per 25 gallons; also, that 1 level teaspoonful of wettabl 
powder per pint equals 1 pound per 25 gallons. Therefore, if your mix calls for a 25- 
gallon solution with 2 quarts of emulsifiable concentrate (EC) and 3 pounds of wettable 
powder (WP) , your conversion is 2 teaspoons of EC and 3 level teaspoons of WP per pint of 
carrier (water or liquid fertilizer) . 

Procedure : (1) Calculate conversion factors for 1 pint of mix. (2) Place 1 pint of 
carrier in each jar and label the jars "A" and "B." (3) Add one -half teaspoon of adjuvant 
to jar marked "A" (adjuvant added). (4) Add the proper amount of chemicals to both jars 
(WP's first). (5) Close the jars and shake or invert to mix. (6) Allow to set and observ 
the results. 



Die compatibility and the amount of agitation needed can be determined by observing jar 
ji'B" (without adjuvant). If the materials remain suspended for over 2 hours without sepa- 
rating, flaking, precipitating, or "gunk" formation, there is no need for extra spray 
adjuvant, and only moderate agitation is needed. If they separate but can be easily 
resuspended , the materials can be combined and applied together with thorough agitation. 

The need for extra adjuvant can be determined by comparing jar "A" (adjuvant added) with 
.jar "B." If the materials in "A" remain suspended while those in "B" do not, then extra 
emulsifier or dispersing agent may make the combination possible. Remember : some 
"fertilizer grade" materials already have extra adjuvants added. 

TESTING FOR HERBICIDE RESIDUE 

Will this year's crop be injured by last year's herbicide? You can find out by growing 
seedlings of susceptible plants in "suspect soil" while you are doing your early spring 
planting or gardening. 

Gather soil samples from areas where you suspect herbicide carryover. Headlands and hills 
that may have received excessive doses because of overlapping or decreased sprayer speed 
are likely areas. You will need about 2 quarts of suspect soil and 2 quarts of untreated 
: soil. Be certain your samples are representative. If you use pint containers, you can 
have 4 containers with "suspect" soil and 4 with untreated samples for comparison. If 
necessary, check samples can be prepared from suspect soil by adding activated charcoal 
(1 gram for each 2 quarts). Activated charcoal capsules of the half -gram size can be 
obtained from most drugstores. 

Place the soil into the containers. Metal or cardboard containers should have holes 
punched in the bottom for drainage. Seed about 15 oats, a half teaspoon of lawngrass 
seeds, or 6 soybean seeds per container. Water the soil, but do not saturate. Place the 
containers in a warm place where they will receive sunlight. Keep the soil moist, but not 
overwet. 

Injury symptoms should appear in about 2 to 3 weeks- -by the time the seedlings are 3 to 
4 inches tall. The time required will depend partly on temperature and moisture. Severe 
injury will result in a complete kill of the seedlings. Marginal injury can best be 
determined by comparing check and suspect samples. 

You can minimize field injury by thoroughly mixing the soil during seedbed preparation. 
Plow rather than disk. Delaying planting will allow greater time for chemical breakdown. 
Another choice is to grow a less-susceptible crop. 

When planning this year's herbicide program, consider what crops you plan to grow next year. 

i 

I PESTICIDES IN WELLS 

, Several calls are received each year about pesticides that accidentally get into a well, 
i Often, the contamination is caused by flushing or overflowing the sprayer near the well. 

Also, water systems with freeze drains or without pressure tanks can back-siphon liquid 

from a sprayer tank if hoses are not removed and the valves closed. 

' Prevention is certainly cheaper and easier than the cure. Close all valves and remove the 
' hose from the tank after filling. But never put the hose inside the tank. A bracket to 
[ hold the hose at the top of the tank will also prevent siphoning. 

! Don't leave the tank while it is filling. And don't flush tanks where the material will 
drain into the well. 



-6- 

SPECIAL ANNOUNCEMENTS 
PESTICIDE DEALERS AND APPLICATORS FIELD DAYS/1: 30 P.M. /EACH DAY 

April 8, Office at Randolph County Extension Adviser, Charles E. Willman, Sparta. 

April 15, Office at Monroe County Extension Adviser, Arlin H. Obst, Waterloo. 

April 16, Office at Madison County Extension Adviser, Warren W. Bundy, Edwardsville. 

Insect and plant disease trouble -shooting will be the general topic, with special emphasis 
on alfalfa weevil and corn borer. 



PUBLICATIONS AVAILABLE 



Circulars: The "1969 Fungicide Guide for Commercial Vegetable Growers" (Circular 999) and 
"Soil Disinfestation Methods and Materials" (Circular 893, Revised) have just been issued. 
Others that you may find helpful are Circular 676, "Soybean Diseases in Illinois," and NC 
Regional Extension Publication No. 21, "Corn Diseases in the Midwest." Single copies of 
these publications may be obtained by contacting your county Extension office or by droppii 
a postcard to the Agricultural Publications Office, 123 Mumford Hall, University of Illino: 
Urbana -Champaign Campus, Urbana, Illinois 61801. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Rosaoe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture , Urbana-Champaign and Illinois Natural His- 
tory Survey. 

PLANT DISEASES: M.C. Shurtleff and M.P. Britton, Department of Plant Pathology . 

WEEDS: Marshal MoGlamery and Ellery Knake, Department of Agronomy; Herb Hopen, Department 
of Horticulture. 

AG COMMUNICATIONS : Del Dahl 

The information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 



J~<>v / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




INSECT. WEED & PLANT DISEASE SURVEY BULLETIN 

STATE/COUNTY/LOCAL GROUPS/U S. DEPARTMEMT OF AGRICULTURE COOPERATIM&. r VT" ">,' .'■'■''" 



- j 



FOR IMMEDIATE RELEASE 



001 



No. 3, April 11, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



FORAGE 



Alfalfa weevil development continues to be slow in the area south of a line from St. Louis 
to Lawrenceville. A few fields in this area had very light feeding on 10 to 30 percent of 
the terminals, but visible damage is not readily apparent. Most larvae are small and are 
found only by close examination of the buds of the plants. Further north, the hatch has 
been delayed. 

Adult alfalfa weevil populations started to build up this week south of Route 50, ranging 
from 20 to 90 per 100 sweeps. The warm days recently caused these adults to become very 
active. Egg laying is increasing rapidly. 

Depending on the weather conditions, insecticide treatments will not be necessary for 7 to 
10 days. Egg- laying and egg-hatch will increase at a rapid rate if the warm weather con- 
tinues. Watch your fields closely during the next week for increasing larval populations 
and feeding damage, particularly on south slopes. As soon as 25 percent of the terminals 
show noticeable feeding, it is time to treat. 

The insecticide recommendations are: 

1. Commercial applicators can apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) with good results. Use azinphosmethyl only once per cutting. Do not 
harvest for 15 days after treatment with methyl parathion, 16 days for azinphosmethyl. 
Wear protective clothing. 

2. Persons not equipped with protective clothing can use a mixture of (1) 3/4 pound of 
malathion and 3/4 pound of methoxychlor per acre, (2) a mixture containing at least 
1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 1-1/4 pounds of 
malathion per acre on days when air temperatures will be above 60° F. for several 
hours after application. Do not harvest for 7 days after treatment with methoxychlor, 
diazinon, or mixtures of them. There is no waiting period for malathion. 

The 24-county European corn borer survival survey is now completed. Nearly all areas in 
the state revealed higher- than -normal survival rates. Several county Extension advisers 
report corn borer survival of 70 to 98 percent. 



-2- 

Percent 
District survival 

Northwest 77 

Northeast 78 

West 73 

Central 64 

East 72 

West -Southwest 80 

East -Southeast 77 

Southwest 95 

Southeast 77 

STATE AVERAGE "8T 

A figure of 70 to 80 percent is considered normal as a survival level- -above 80 is high, 
and under 70 is below normal. Weather and farm practices may well determine the extent 
of the corn borer problem this summer. 

Fungus gnats are numerous in some wheat fields , as well as in many buildings and homes . 
These small, gnat-like flies (sometimes mistaken for the Hessian fly) develop in wet, de- 
caying organic matter. They manage to crawl through window screens, becoming a nuisance 
in homes. Inside the home, a 0.1-percent pyrethrin space spray applied from a pressurized 
can will give quick knockdown and relief. 

Clover leaf weevil populations remained about the same as last week. From 2 to 4 per squan 
foot were found in the central section of the state. All were less than half -grown and wen 
difficult to find. 

Watch new seedlings of red clover and alfalfa for leaf damage. The presence of warm, rainy 
weather is favorable for a fungus disease. Such a disease will reduce the number of 
weevils. 

Potato leafhoppers are now present in alfalfa around the southern half of the state. They 
are small, green, wedge-shaped insects that skid sideways when disturbed. They cause 
yellowing on second and third cuttings of alfalfa. No control is recommended at this time. 

Clover mites are also becoming annoying in some homes. These mites are tiny, orange-to- 
black moving specks about the size of a pinhead. They cover furniture, walls, curtains, 
window sills, etc. as they attempt to find their way outdoors. They can be picked up with 
a vacuum cleaner, or an 0.1-percent pyrethrin spray from a pressurized spray can will 
give quick relief. Before fall, remove grass, clover, and weeds next to the foundation- - 
leaving a strip of soil at least 18 inches wide. This bare soil serves as a barrier to the 
mites. Replanting this strip with flowers, such as zinnia, marigold, chrysanthemum, or 
salvia will prevent a clover -mite problem next year. 

Winged termites and ants are appearing and are causing concern to homeowners. If swarms of 
flying termites appear, check for mud tubes on inside basement walls and on the outside of 
foundations. Many termite -control problems are extremely complicated and require an ex- 
perienced exterminator. 



TERMITE or ANT? the differences are: 

ANTENNA ELBOWED 



TERMITE 




WINGS(IFPRESENT) 
MANY SMALL VEINS 
BOTH WINGS 

SAME SIZE 




ANTENNA 
NOT ELBOWED 



:'CHEMISE" 
V WAIST 

"HOUR- 
GLASS"! 
WAIST' a 

WINGS 

(IF PRESENT) 

FEW VEINS 

^"HIND WINGS SMALLER THAN 

FRONT WINGS 



NOT FOR PUBLICATION: SPECIAL NOTE TO RADIO AND TELEVISION STATIONS 

You can have University of Illinois entomologists on your station each Friday or Saturday 
telling farmers how to best control their insect pests. All you do is telephone (217) 
333-2614 each Friday. An automatic answering device will play a recording with U. of I . 
entomologists summarizing the week's insect activity and forecasting next week's problems. 

This year both the southern and northern Illinois insect report will be available at the 
same time. 

Each report will be 2 minutes long. You may record either report each time you call. 
You'll be getting a higher broadcast quality report this year since the playback machine 
is of professional standards. 

For more information or in case of difficulty call Gene Stanley (217) 333-4782. 

For the northern and the southern Illinois insect report call (217) 355-2614 each Friday 
between the hours of 6 a.m. and 5 p.m . 



WEEDS 



LASSO GRANULES CLEARED 



Lasso 10-percent granules have now been cleared for use, 
so the herbicide is cleared for both soybeans and corn. 
for soybeans in 1969. 



Lasso liquid was cleared earlier, 
Primary emphasis will likely be 



So far, in both soybean and corn trials, tolerance appears to be good with Lasso. For 
most individuals, Lasso is less irritating than Randox or Ramrod, and it controls about 
the same spectrum of weeds as Ramrod. 

However, compared to Ramrod, Lasso may perform somewhat better on the lighter soils, may 
hold up better under relatively heavy rain, and may control weeds slightly longer. Under 
low-rainfall conditions, Ramrod may sometimes perform slightly better than Lasso. 



-4- 

Lasso should be used for surface -applied preemergence application, at planting time or soo 
after. Rates should center at about 2 pounds of active Lasso per acre- -2 quarts of the 
liquid, or 20 pounds of granules- -on a broadcast basis. Reduce the rate proportionately i 
you're banding. Rates can be safely varied 1/2 pound either way, depending on soil type 
and the degree of control desired. 

TREFLAN CARRY-OVER 

Some treflan used on soybeans in 1967 carried over and affected a few 1968 cornfields. 
Low rainfall conditions in the fall and spring of 1967 probably contributed to a slower 
degradation of the Treflan. Most of the fields where the problem occurred had only been 
disked or chisel -plowed. 

Using a moldboard plow dilutes the herbicide more than disking or chisel -plowing. To avoi 
carry-over problems, uniform and accurate applications of no more than recommended rates 
are important. 

The results of one experiment indicate that the granule may have a longer persistence thai 
the liquid formulation. 

Although the Treflan residue problem was not widespread or serious, some consideration and 
caution seems appropriate, in order to avoid any possible problems in 1969 and 1970. 

HOMEOWNER WEED PROBLEMS 

Prevent crabgrass . Crabgrass is especially widespread in southern Illinois, but it is a 
serious lawn problem throughout the state. If you've had crabgrass in your lawn in past 
years, consider using a herbicide. 

Today, many excellent preemergence herbicides are available that will prevent crabgrass ir 
festations. Often, these materials will control other annual grasses and some broadleaf 
weeds as well. Used as directed, the materials give consistent crabgrass control when 
applied to established Kentucky bluegrass lawns. 

Most of the preemergence chemicals are sold to the homeowner in dry form for application 
with a lawn spreader. Pay particular attention to proper spreader setting, in order to 
realize the desired results. 

Preemergence materials should be applied early in the season before the crabgrass seed 
germinates. A rule of thumb often used is to apply the chemical before the petals of the 
early blooming magnolia fall. 



PLANT DISEASES 



CONTROL DAMPING-OFF OF SEEDLINGS 

Vegetable, flower, tree, and other seedlings may suddenly wilt and wither or collapse fror 
a decay that strikes at the ground line or below. Usually, the decay is caused by soil- 
borne fungi. 

Damage is most common in cold, heavy, wet soils and in shady areas where air circulation 
is poor. One answer is to grow plants in soil that has been treated with a broad-spectrum 
soil' fumigant. Once damping-off starts, here's what can be done to save the rest of the 
seedlings. 



1. Keep soil on the dry side. 

2. Avoid overcrowding, excessive shade, too-deep planting, and overwatering- -especially 
with nitrogen. 

5. Water seedlings at 5- to 7-day intervals with ferbam or ziram 76-percent wettable 

powder (2-1/2 level tablespoons per gallon of water); or use captan, thiram, zineb, or 
folpet (all 50- to 76 -percent WP) at the rate of 1 to 1-1/2 tablespoons per gallon. 
Apply about 1/2 pint per square foot of bed surface, using a watering can or coarse 
sprinkler. 

4. Be sure to buy and plant only top-quality seed that has been treated with a protectant 
fungicide (such as captan or thiram). The seedbed soil should naturally be well- 
prepared, deep, and well-drained. 

SPRAYING FRUITS TO CONTROL DISEASE 

The present period- -from the bud-swelling to early bloom stage- -is a critical time in con- 
trolling a wide range of fruit diseases --including apple scab, powdery mildew, and cedar 
rusts; peach- leaf curl and plum pockets ( buds must still be dormant or the treatment is too 
late); brown rot blossom blight of stone fruits; strawberry leaf diseases; anthracnose and 
spur blight of brambles; and grape black rot. Suggested spray schedules are given in 
Circular 936 Pest Control in Commercial Fruit Plantings , Fruit Leaflet No. 1 Strawberry 
Spray and Dust Guide, and Circular 935 Growing Small Fruits in the Home Garden. Copies 
may be obtained from the Office of Agricultural Publications, 123 Mumford Hall, Urbana 
61801. 

Captan is the best all-around fungicide for fruits, especially for the home fruit grower. 
It is widely sold in multipurpose fruit-spray and dust mixes that can be applied to prac- 
tically all fruits. If powdery mildew is a problem, Karathane or sulfur can be added to 
the captan. If rusts are important, add thiram, zineb, or maneb to the mix. 

Dikar is a new fungicide for the commercial apple grower. It is sold by Rohm $ Haas and 
is a mixture of their Dithane M-45 and Karathane. It has been highly effective in con- 
trolling scab, powdery mildew, and rust diseases. 

NEW SOIL DISINFESTATION CIRCULAR 

Soil is treated by heat or chemicals to destroy disease-causing organisms (including 
nematodes), insects, and weed seeds in the soil. The process eliminates the need to change 
soil in greenhouses, cold frames, hot beds, and other plant beds. A complete, up-to-date 
discussion of this subject is given in a revised Circular 893, Soil Disinfestation Methods 
and Materials. Copies may be obtained from your County Extension Office or by writing to 
the Office of Agricultural Publications, 123 Mumford Hall, Urbana 61801. 



PUMPS FOR FIELD-SPRAYING 



The roller pump is still the one most-commonlv used because of its low cost and avail- 
ability! The principal complaint against the roller pump is that the rollers wear rapidly, 
especially when used for pumping suspensions of wettable powders. Generally, the capacity 
of the roller pump can be restored by replacing the rollers, if the housing is not severely 
damaged. However, much of the wear or damage to the pump may be caused by the way it is 
used and stored. 



Roller pumps- -or any pump for that matter- -should not be operated dry. Excessive heat wil 
damage the rollers and seals. With a clear suction line and an open discharge line, the 
pump should displace liquid within 15 seconds. When used for spraying wettable powders, 
roller pumps should not be shut off as long as the wettable powder suspension is in the 
pump housing. If the pump is shut off, the wettable powder will settle to the bottom of 
the pump and will cause damage when the pump is started up again. 

The water used should be free of suspended solids that can cause wear. Use only clean 
water that is filtered while filling the tank. 

The centrifugal pump is rapidly gaining in popularity, and it is recommended over the 
roller pump for handling wettable powders. A centrifugal pump made of abrasion-resistant 
materials will pump wettable powder suspensions satisfactorily. Its capacity is high, so 
keeping wettable powders in suspension should not be a problem if an adequate bypass syste 
is used. It is readily available for tractor-PTO use at a reasonable price. But the 
centrifugal pump is more expensive than the roller pump. The main limitation of the cen- 
trifugal pump is its maximum pressure. However, such pumps are entirely adequate for 
field applications of herbicides, liquid fertilizers, and most insecticides. 

The piston pump , if properly constructed, will handle wettable powders satisfactorily. 11 
provides far more pressure than is needed for most field spraying but the increased pressii 
may be necessary for fungicide applications. 



SPECIAL ANNOUNCEMENTS 



Pesticide Dealers and Applicators Field Days/1: 30 p.m. each day 

April 15, Office of the Monroe County Extension Adviser, Arlin Obst, Waterloo. 
April 16, Office of the Madison County Extension Adviser, Warren Bundy, Edwardsville . 
April 22, Office of the Greene County Extension Adviser, Eldon Starkweather, Carrollton. 
April 23, Office of the Macon County Extension Adviser, Warren Myers, Decatur. 

Insect and plant disease trouble -shooting will be the general topic with special emphasis 1 
on alfalfa weevil and corn borer. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Rosooe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural His- 
tory Survey. 

PLANT DISEASES: M.C. Shurtleff and M.P. Britton, Department of Plant Pathology. 

WEEDS: Marshal McGlamery and Ellery Knake , Department of Agronomy; J.D. Butler, Departmev 
of Hortioulture . 

AG ENGINEERING: John Siemens. 

AG COMMUNICATIONS: Del Dahl. 

The information for this report was gathered by these people, staff members, county Extcn 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 



I- sir / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 

TATE/COUNTY/LOCAL GROUPS/U S DEPARTMEMT OF AGRICULTURE COOPERATING ip'tV ' 



i-W 



: 



FOR IMMEDIATE RELEASE 



USR0- 



No. 4, April 18, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



FORAGE INSECTS 

Alfalfa weevil development, although still slower than normal south of Highway Route 50, 
did speed up this week. Insecticide applications should be made now in the more-severely 
infested fields. Fields that had feeding on 10 to 30 percent of the terminals last week 
low show 40- to 50 -percent terminal feeding; 5 to 10 percent of the terminals had severe 
feeding; 20 percent, moderate; and 20 percent, light. Although most larvae are small and 
^an be found only through close examination, they are growing rapidly. Expect more damage 
to appear this week. 



In the area south of Highway 50, weevil adults are also more numerous. 
160 per 100 sweeps of an insect net, compared with 20 to 90 last week, 
creasing- -so will larval populations and damage. 



Populations reached 
Egg- laying is in- 



Further north, weevil activity is just beginning. Here there was feeding on 5 to 20 per- 
cent of the terminals, and there were 1 to 5 worms per infested terminal. Egg -laying and 
natch will accelerate with warm weather. Those worms already there will grow and feed, so 
insecticide control may be justified late in the week of April 21. 

fetch all alfalfa fields closely from now on. As soon as 25 percent of the terminals show 
loticeable feeding, apply an insecticide- -unless the field is within two weeks of harvest. 
In that case, cut early and treat the new growth. 

Die insecticide recommendations are: 



I. Commercial applicators can apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) with good results. Use azinphosmethyl only once per cutting. Do not 
harvest for 15 days after treatment with methyl parathion, 16 days for azinphosmethyl. 
Wear protective clothing. Slight discoloration of alfalfa may occur after the use of 
parathion. 

I. Persons not equipped with protective clothing can use a mixture of (1) 3/4 pound of 
malathion and 3/4 pound of methoxychlor per acre, (2) a mixture containing at least 
1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 1-1/4 pounds of 
malathion per acre on days when air temperatures will be above 60° F. for several 
hours after application. Do not harvest for 7 days after treatment with methoxychlor, 
diazinon, or mixtures of them. There is no waiting period for malathion. 



Pea aphids are appearing in occasional southern Illinois alfalfa fields, but are not plen- 
tiful enough to be serious at present. The current warm and calm weather, with the mois- 
ture now present, will promote the spread of a fungus disease of aphids, which would kill 
them. Diseased aphids are brown and flattened, and often have a white mold about them. 

Insecticides are recommended for alfalfa weevil control, also for the control of pea aphid: 

CORN INSECTS 

Flea beetles are now common in fence rows and wheat fields. They will soon migrate to 
corn. These black beetles strip narrow lines on the leaves, leaving the white tissue. Th( 
beetles are tiny and jump at the slightest disturbance. Approach the plants slowly or the 
beetles will have disappeared before you get to the plant. 

This beetle transmits Stewarts disease of corn. We know so little about the time of inocu 
lation that we cannot recommend beetle control to prevent disease infection this early. I: 
the beetles are killing or severely damaging plants, sprays of toxaphene or carbaryl will 
prove helpful. 

Black cutworm moths were found this week for the first time this year. 

HOMEOWNER INSECTS 

Elm leaf beetles that have wintered in the wall voids and partitions are now trying to get 
outside. These yellow and brown- striped beetles are a nuisance when they migrate into the 
home rather than outside. Usually, they congregate between the storm sash or screen and 
the window. Leave the outer window partly open and they will go outdoors. Inside the 
home, use a vacuum sweeper to pick them up. 

Bagworms are still in the egg stage in any bagworm sacks from last year that are still 
hanging. For the next three to four weeks, hand pick and burn these bags. This will re- 
duce the number of bagworms that will hatch in late May and early June. Although hand- 
picking may not eliminate the need for sprays, it will at least reduce the number of worms 
that will be present later on. This will help substantially in controlling them. 

Spring cankerworms (often called inch-worms) are dark-brown-to-green measuring worms that 
feed on the buds and newly emerging leaves of trees like elm and apple. Full grown, the 
worms drop to the ground on silk threads. Hundreds of them can be seen hanging from a 
tree. When this happens, it is too late to spray. If the infestation is found when the 
worms are small, sprays of carbaryl (Sevin) or lead arsenate will provide control. A 
bacterial spray is also available, which is reported to be effective. 

Millipedes are moving into homes from shrubbery beds, lawns, storm sewers, and from mounds 
of dirt and refuse made by excavations in new subdivisions, where the soil is filled with 
decaying vegetation. 

In cases of heavy migration, spray lawns and shrubbery beds with carbaryl or diazinon. Th: 
provides a barrier zone in which the millipedes are killed, preventing them from getting 
into the home. 

For minor problems, limited spraying of a 3- to 4-foot-wide area around the house founda- 
tion should be adequate. Apply approximately 2 pounds of actual carbaryl or 1 pound of 
actual diazinon in 25 gallons of water for each 10,000 square feet of area treated. 



^alls on trees, especially maple and oak, are caused by tiny insects that have hatched from 
:ggs layed in the leaves. These tiny insects burrow into the newly developing leaves. The 
>lant then grows the galls around the insect. 

Spraying with malathion at or immediately after new leaves develop will help control these 
>ests. However, these galls rarely, if ever, kill the tree. 



NEEDS 
IERBICIDES AND SEED CORN PRODUCTION FIELDS 

wo big problems in seed production fields have been late -season weed control and inbred 
.ines susceptible to herbicidal injury. Herbicides with close crop tolerance may injure 
iome inbred corn lines, causing a failure of male- and female-parent lines to "nick." 

Several herbicide labels caution about use on inbred lines of corn or in seed production 
: ields. Eptam, Randox-T, and Dowpon have not been recommended for seed production fields 
.n the past. Currently, Primaze and Sutan are not suggested for this purpose. Primaze is 
l combination of atrazine and prometryne, and prometryne has some potential for corn in- 
ury. 

lany seed producers have had a problem with late-season grass control. Sutan has shown the 
ibility to control some of these grasses such as fall panicum, witchgrass, and crabgrass. 
lany inbred corn lines were evaluated in 1968 for their susceptibility; most lines showed 
;ood tolerance. However, a few lines were initially injured, but did recover. 

jeed producers and custom applicators should be cautious about using herbicides with close 
:rop tolerance on seed production fields. If such a herbicide is used, care must be taken 
r ith calibration, formulation, and application. 

REVISION OF JOHNSONGRASS CONTROL 

he spring treatment program for Johnsongrass control has been changed to shorten the time 
•etween application and planting of corn and soybeans. Current label directions are: 

. Allow Johnsongrass to grow until 8 to 12 inches tall. 

. Apply 5 to 7 pounds of Dowpon per acre as a foliar spray. 

Wait 3 days after spraying, then plow. 

. Wait at least 5 days after plowing to plant corn or soybeans. If dry weather persists, 
wait at least 5 days after receiving a minimum of a half an inch of rainfall. 

his clearance shortens the time between spraying and planting by 2 to 4 weeks. The delay 

etween spraying and plowing allows absorption and translocation of Dowpon into the Johnson- 

rass. The waiting period between plowing and planting allows breakdown of the Dowpon so 
hat it won't injure the corn or soybean crop. 

his change makes the spring program more flexible and allows earlier planting than was 
reviously possible. The major concern is the possibility of crop injury if planting is 
oo soon after plowing. The most- effective control program for established Johnsongrass 
s still the summer program after small grains. 



The seedling or "new grass" treatment is a vital part of any Johnsongrass control program. 
The seedlings are controlled by a preemergence herbicide. We suggest using Sutan in corn- 
Treflan, Planavin, or Vernam in soybeans. 

HERBICIDE INCORPORATION 

Most annual weed seeds germinate in the top 2 inches of the soil and the herbicide is 
usually needed here for the best results. Incorporation prevents surface losses of vola- 
tile herbicides and moves low-solubility herbicides into the soil. Most herbicides of 
moderate solubility move into this weed seed zone with normal rainfall. 

To incorporate herbicides, use a tandem disk-harrow or a rotary tiller. With powered 
rotary tillers, the distribution of the herbicide is best when the increment of cut is 
2 inches and when many knives are used as possible--at high rotor speeds or slow ground 
speeds. However, powered rotary tillers are not available on most farms and they do not 
always leave the most-desirable seedbed. The tandem disk is the tool most commonly used 
for herbicide incorporation. The disk does not incorporate as uniformily as the rotary 
tiller. And it has a tendency to partially invert a soil slice, concentrating the pesti- 
cide along a diagonal plane parallel to the direction of travel. A single disking results 
in zones of high concentration. In tests by the Agricultural Engineering Department, an 
additional disking did not increase the uniformity of incorporation much. 

Studies of the effects of travel speed and gang angle show that the distribution can be im- 
proved when gang angle is increased and the tandem disk is used at high, but safe, speeds. 
The soil should be loose and not too moist for best results. A wet, sticky soil resists 
incorporation. 

The tandem disk should be operated at a depth of about 4 inches for best results. Greater 
depths may cause excessive dilution of the herbicide. 

Field cultivators, chisel plows, and spring-tooth harrows are not satisfactory because they 
primarily just shatter and lift the soil. They cause the finer particles to be moved down- 
ward, leaving the clods on top and little mixing occurs. 



PLANT DISEASES 



WHEAT DISEASES 

Septoria leaf blotch is abundant now on the lower leaves of plants in nearly all Illinois 
fields. The disease has spread upward to new leaves during the last week throughout the 
southern one-half of Illinois. 

In Gage wheat, septoria is especially severe in combination with infection by soil-borne 
wheat mosaic virus . The .symptoms of the combined diseases are apparent as irregular areas 
of yellowed wheat. Individual leaves are mottled from the virus infection. The septoria 
infection produces a streaking. 

Recovery from the virus symptoms will occur in two to three weeks. But septoria infection 
may remain heavy throughout the rest of the growing season. 

Powdery mildew may appear anytime on wheat and winter barley in southern Illinois where the 
crop is dense and fertility- -especially nitrogen- -is high. Mildew has become an increas- 
ingly important disease in recent years as farmers have increased the use of fertilizers 
and rate of seeding. High nitrogen produces a rank, dense growth that creates an ideal 



-5- 

twironment for the development of the mildew fungus. For more information read Report on 
lant Diseases No. 104, "Powdery Mildew of Wheat and Barley." Copies may be obtained by 
riting to the Department of Plant Pathology, 218 Mumford Hall, University of Illinois at 
rbana- Champaign, Urbana 61801. 

HOULD SOYBEAN SEED BE TREATED WITH A SEED-PROTECTANT FUNGICIDE? 

=ed treatment fungicides- -containing captan, thiram, or chloranil- -protect seed against 
;ed-decay fungi and help ward off soil-born organisms that infect just before or just 
fter emergence. 

l Illinois and surrounding states, soybean seed treatment tests have usually shown that 
roper seed treatment improves the germination of poor-quality seed, but has little or no 
Efect on the germination of high-quality seed- -except under very stress conditions such 
5 cold, wet soil and deep planting. 

;ed treatment often increases the emergence of low- germinating seed by 10 to 50 percent, 
it such increases are seldom accompanied by increases in yield. Our thoughts may change 
l the above points based on extensive trials planned this spring. You will hear more about 
lis after harvest. 

; feel that farmers should plant only top-quality, certified seed (germination 85 percent 
: more) . This gives the soybean grower the best protection against low- germinating seed 
lat is shriveled, cracked, moldy, badly weathered, split, or immature. Sowing top-quality 
?ed is the best guarantee for a thick, uniform stand of vigorous plants. 

IUIT DISEASES ARE ACTIVE NOW 

irays should be applied to strawberries, brambles, apples, pears, stone fruits, and grapes 
: 7- to 10-day intervals. This will keep new foliage (and later fruit) protected during 
^riods of wet weather when infections occur. 



NEW PUBLICATIONS 



dversity of Illinois Circular 1001, Home Orchard Pest Control, has just been published. 
: will be available from county Extension advisers and the Office of Agricultural Publica- 
ons, 123 Mumford Hall, Urbana 61801. This circular covers insect, disease, and weed- 
mtrol suggestions for the various tree fruit crops. A multipurpose spray is suggested. 



SPECIAL ANNOUNCEMENTS 



sticide Dealers and Applicators Field Days/1: 30 p.m. each day: 

ril 22, Office of the Greene County Extension Adviser, Eldon Starkweather, Carrollton. 
ril 23, Office of the Macon County Extension Adviser, Warren Myers, Decatur, 
ril 29, Office of the Iroquois County Extension Adviser, Kenneth Imig, Watseka. 

sect and plant disease trouble -shooting will be the general topic, with special emphasis 
alfalfa weevil and corn borer. 



SPECIAL NOTE TO RADIO AND TELEVISION STATIONS 



u can have the insect situation report on your station each Friday or Saturday. Tele- 
:'one (217) 333-2614 each Friday. An automatic answering device will play a recording with 
of I. entomologists summarizing the week's insect activity and forecasting next week's 



problems. There is a southern- and northern-Illinois report, each 2 minutes long. You 

may record either report each time you call. For more information or in case of difficulty 

call Gene Stanley (217) 333-4782. To get the northern- and southern-Illinois insect re- 
ports call (217) 333-2614 each Friday between 6 a.m. and 5 p.m. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Bon Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture , Urbana-Champaign and Illinois Natural His- 
tory Survey. 

PLANT DISEASES: M.C. Shurtleff and M.P. Britton, Department of Plant Pathology. 

WEEDS: Marshal MoGlamery and Ellery Knake, Department of Agronomy; J.D. Butler, Department 
of Horticulture. 

AG ENGINEERING: John Siemens. 

AG COMMUNICATIONS : Del Dahl. 

The information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 



J- L 7 




COLLEGE OF i 

AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




INSECT WEED & PLANT DISEASE SURVEY BULLETIN 

STATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMEMT OF AGRICULTURE COOPERATING 



;qr immediate release 



II 



No. 5, April 25, 1969 



!%is series of weekly bulletins provides a general look at the insect, weed, and plant 
iisease situation (fruit and commercial vegetables excepted) , along with suggested, 
ibbreviated control measures. Each individual should check his own fields to determine 
teoal conditions. 



INSECTS 



'ORAGE INSECTS 

U.falf a weevil varies greatly from field to field and from area to area. In some fields 
vhere alfalfa growth is extremely slow, weevil development is equally slow; where alfalfa 
Is growing rapidly, weevil development is also progressing rapidly. This reflects the 
jffect of wind breaks, field slopes (south and west exposures warm up earlier) , and similar 
factors that affect early growth. Each field must be examined to determine the weevil in- 
festation. 

Since last week, weevil populations have jumped visibly in the area south of a line from 
Carmi to Pinckneyville to Sparta. This week, we found up to 2,300 larvae per 100 sweeps 
)f an insect net- -compared to only 200 last week. Terminal feeding varied from a low of 
.0 percent in some fields to a high of 75 percent in others. The ideal treatment period 
started this week and will continue into next week (the week of April 28) . If a field is 
athin 2 weeks of harvest, you may choose to cut early, remove the hay, and spray the new 
growth. 

! rom the Carmi- to- Sparta line north to Highway 50, the weevil populations are not high 
ret. They range from 100 to 300 per hundred sweeps of an insect net. In this area and 
iust to the north of it, the variation between fields is quite noticeable; so each field 
iust be examined. Populations are increasing here and insecticide treatments may be 
leeded by the middle or latter part of the week of April 28. Early cutting may also be 
i partial answer to weevil control there. 

Tie weevil situation varies greatly in the area between Highway 50 and a line from Paris 
:o Mattoon to Carlinville. Although treatment may be warranted in an occasional field 
.ate the week of April 28, treatment generally will not be necessary until the week of 
lay 5- -unless weather becomes unseasonably warm. Early cutting, hay removal, and spray - 
ng new growth may help answer the weevil problem by then. 

Ms year, as last, one application may be enough to protect the first cutting, but watch 
he new growth carefully because new shoots may need protection. If fields are more than 
! weeks from harvest and 25 percent of the terminals show noticeable feeding, treat them. 

he insecticide recommendations are: 

Commercial applications can apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) with good results. Use azinphosmethyl only once per cutting. Do not 
harvest for 15 days after treatment with methyl parathion, 16 days for azinphosmethyl. 
Wear protective clothing. 



2. Persons not equipped with protective clothing can use a mixture of (1) 3/4 pound of 
malathion and 3/4 pound of methoxychlor per acre , (2) a mixture containing at least 
1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 1-1/4 pounds of 
malathion per acre on days when air temperatures will be above 60° F. for several 
hours after application. Do not harvest for 7 days after treatment with methoxychlor 
diazinon, or mixtures of them. There is no waiting period for malathion. 

Pea aphids are becoming more common in alfalfa fields in the southern part of the state. 
Fortunately, a few lady beetles are also appearing. If these natural enemies of the aphij 
increase in number, they will help with aphid control. 

CORN AND SMALL GRAIN INSECTS 

True armyworm and black cutworm moths are moving northward from states to the south of us 
These armyworm moths arrive early and will lay eggs in the grass along fence rows , ditch 
banks, roadsides, and in pastures where the growth is thick and rank. Soon they will con 
centrate their egg- laying in rank stands of wheat, barley, and rye. Black cutworms will 
lay their eggs in cornfields --in the low wet spots, poorly drained portions, and grassy 
areas. Cool, wet weather favors both armyworm and cutworm development. It is too soon 
as yet to predict possible problems with these insects. 

HOMEOWNER INSECT PROBLEMS 

Aphids are appearing on hawthorn trees, as well as on other trees, shrubs, and flowers. 
These small, green, black or red, soft-bodied insects congregate on developing buds and 
leaves and suck the sap. If aphids are numerous and control appears necessary, spray the 
foliage with malathion (2 teaspoons of the 50- to 57-percent liquid concentrate per gallo: 
of water) or with diazinon (2 teaspoons of the 25-percent liquid concentrate per gallon o 
water) . These sprays will also control mealybugs and help reduce the number of mites . 

Clover mites are still a nuisance in some homes. They scatter out over furniture and on 
walls, curtains, window sills, etc .- -particularly on the south and west sides of the 
house. Pick them up with a vacuum cleaner, and/or use a 0.1-percent pyrethrum or 0.5- 
percent dichlorvos (DDVP) spray from a pressurized spray can for quick knockdown. Before 
fall, remove all grass, clover, and weeds next to the foundation- - leaving a strip of bare 
soil at least 18 inches wide. By replanting this strip with flowers such as zinnia, mari 
gold, chrysanthemum, rose, or salvia, you will prevent problems with clover mites next yei 



WEEDS 
HERBICIDES AND SOIL ORGANIC MATTER 

The amount of organic matter in the soil influences the performance of many herbicides. 
Illinois mineral soils vary in organic matter content from 0.5 to 7 percent. 

There are several ways of estimating the organic-matter content of your soils. A chemical 
laboratory test is the most-accurate one. 

Another option is to use the Color Chart For Estimating Organic Matter In Mineral Soils Ii 
Illinois, AG- 1941. A third option is to use Bulletin 725, Soils of Illinois. The chart 
and bulletin are available through your count)'' Extension adviser. V 

1/ They are also available from the Office of Agricultural Publications, 123 Mumford Hall : 
or the Agronomy Extension Office, N-305 Turner Hall, University of Illinois at Urbana- 
Champaign, Urbana 61801. 



-5- 

fe suggest adjusting the rates to organic-matter levels on these corn herbicides: AAtrex 
atrazine) , Princep (simazine) , prometryne, Lorox (linuron) , and Lasso. Thus, combinations 
rhich contain one or two of these herbicides --such as Primaze, Londax, Sutan- atrazine, 
.amrod- atrazine, and atrazine- linuron- -are also affected by the level of organic matter. 

reflan, Planavin, Lasso, and Lorox are soybean herbicides that are affected by the organic- 
latter level in the soil. Lorox tolerance to soybeans is close, so no more than one pound 
if Lorox SOW -(50 percent ai) is suggested for each percent of organic matter. This will 
laximize control and will minimize injury. 

VY BEANS FOR SEED 

hese preemergence herbicides are presently cleared for use on soybeans for seed, or on re- 
ilanted beans: Ramrod, Londax (a mixture of Lorox and Ramrod), and Preforan. They are not 
o be sold for use in food, feed, or oil markets. 



PLANT DISEASES 
'HEAT 

eptoria leaf blotch . The situation is about the same as last week. Older leaves are 
ellowed or dead, and black specks (pycnidia of the Septoria fungus) are common in older 
pots on spring- formed leaves. 

oil-borne mosaic . Last week, gage wheat showed some yellowing and mottling of leaves. 
he wheat is growing out of this now, and the new leaves are a healthy green. No further 
i.amage is expected. Mosaic is only serious in cold weather in low, wet areas where sus- 
eptible hard wheats are grown. 

' j'owdery mildew . This can now be found in light amounts within about a third of the fields 
s far north as Jasper County. Mildew is prevalent only in heavily fertilized fields. We 
xpect the disease to move north during the coming week. 

eaf or stem rusts . There is no evidence of these at present. 

LFALFA 

spring black stem . This is common now in southern Illinois within the counties sampled- - 
hite, Jefferson, and Hamilton. Look for dark, slightly sunken areas on the stem and leaf 
etioles. Small, dark spots will also show on the leaves, Many of these leaves will be 
urning yellow and dropping off shortly. 

rown rot . Some of this is evident, along with heaving damage. Crown- rotting fungi enter 
hrough wounds caused by heaving, frost damage, and other types of winter injury. Abundant 
oil moisture is keeping these plants alive. But some plants will probably die during 
oisture-stress periods later on. 

LOVERS 

; ields look good so far. The only diseases evident are the viruses . Symptoms vary, depend - 
ng on the virus and the species of clover. Infected plants are usually stunted or dwarfed 
nd are "bunchy," with yellow and mottled leaves. Regular or irregular yellow patterns may 
evelop along the veins of the leaves. 



LAWNS 



1 



With all the recent rains, mushrooms will be popping up in lawns and near old stumps. Ther< 
is no effective chemical control. To avoid worry about poisoning pets or children, collect 
or rake the mushrooms by hand or mow over them. 

Warn homeowners about the chances of poisoning. Only a trained mycologist can tell poisonoi 
types from those that can be eaten. Mushrooms usually grow from rotting wood or other de- 
caying organic material in the soil. They are common in areas of buried tree stumps, dead 
roots, logs, and boards. Expect them any time following heavy rains or watering to mid-fal! 

One means of lasting control is to dig up the buried wood. Otherwise, let the mushroom 
mycelium in the soil go ahead and complete the decay. Then they will disappear. 

STORED CORN AND SMALL GRAINS 

As the weather warms up, storage rots and the molds that cause them will become active. Th< 
symptoms are: (1) discoloration of the germ or embryo; (2) evidence of mold growth (bluish- 
green, green, tan, white, black, or pinkish- red material) ; (3) "caking" together to form a 
crust- -usually at the center and top of a bin; and (4) a musty odor. Bins should be checkei 
frequently for "hot spots" or the formation of a moldy crust. 

USEFUL REFERENCES 

You can obtain copies by writing to the Department of Plant Pathology, 218 Mumford Hall, 
University of Illinois at Urbana- Champaign, Urbana 61801. Ask for Reports on Plant Disease; 
(RPD's) by number: 

Soil-Borne Mosaic of Winter Wheat (RPD 102, Revised) 

Powdery Mildew of Wheat and Barley (RPD 104, Revised) 

Leaf and Stem Diseases of Alfalfa (RPD 301) 

Root and Crown Troubles of Alfalfa (RPD 302) 

Virus Diseases of Alfalfa and Clovers in Illinois (RPD 307, Revised) 

Storage Rots of Corn (RPD 206) 

NEW SOIL DISINFESTATION CIRCULAR 

Soil is treated by heat or chemicals to destroy disease -causing organisms (including nema- 
todes) , insects, and weed seeds in the soil. The process eliminates the need to change soi! 
in greenhouses, cold frames, hot beds, and other plant beds. A complete, up-to-date dis- 
cussion called "Soil Disinfestation Methods and Materials" is given in the newly revised 
Circular 893. Copies may be obtained from your county Extension office or by writing to 
the Office of Agricultural Publications, 123 Mumford Hall, University of Illinois at Urbana- 
Champaign, Urbana 61801. 



A WORD TO THE WISE 



Keep a record of the insecticides you use. Include the trade name, percentage of active 
ingredients, and the dilution- -as well as the rate of application and the dates of appli- 
cation. If you are ever questioned, you have the records. 

Because of tight credit and bad weather, farmers are not buying farm chemicals. Dealers 
who ordinarily would have sold out a good share of their stock and reordered by now have 
not done so this year. 



hances are, when the weather breaks, farmers will all want their chemicals at the same 
ime. Some farmers may find that the chemical they want is not on hand. Because of clogged 
istribution channels, it may not be available for several days. 

o avoid having to choose an alternate chemical, farmers should either buy now or place an 
rder for the chemicals they want. By doing this, they can be fairly certain that their 
hemical will be available when the rush comes. 



SPECIAL NOTE TO AGRICULTURAL EXTENSION ADVISERS 



et us know immediately about any fields of corn where the stand has been seriously damaged 
y seed-corn beetles. Dr. Ralph Sechriest is anxious to locate these fields for test purposes. 

o those willing Extension advisers who agreed to dissect stalks each week in order to help 
etermine corn-borer development in their area- -sharpen your knives! We would appreciate it 
f you would count 25 live specimens (larvae, pupae, or empty pupal cases) and have the re- 
ort in the mail by Tuesday afternoon. Begin dissections the week of April 27 in the southern 
ection, the week of May 4 in the central section, and the week of May 11 in the northern 
ection. Stan Ceglinski, Cairo, Illinois, found no borer pupation on April 21. 



SPECIAL ANNOUNCEMENTS 



esticide Dealers and Applicators' Field Days/1:30 p.m. each day: 

ipril 29... Office of the Iroquois County Extension Adviser, Kenneth Imig, Watseka. 
ay 6 Office of the Grundy County Extension Adviser, Albert Pilch, Morris. 

nsect and plant disease trouble -shooting will be the general topic, with special emphasis 
n the alfalfa weevil and the corn borer. 



EAD THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

'his weekly report was prepared as follows: 

NSECTS: H.B. Petty, Steve Moore, Rosaoe Randell, Don Kuhlman, and Stephen Sturgeon, 
'niversity of Illinois College of Agriculture , Urbana- Champaign and Illinois Natural 
'istory Survey. 

'LANT DISEASES: M.C. Shurtleff and M.P. Britton, Department of Plant Pathology. 

1EEDS: Marshal McGlamery and Ellery Knake, Department of Agronomy. 

.G COMMUNICATIONS : Del Dahl. 

he information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
'lant Pest Control Branch. 



J- /ȣ, / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




INSECT WEED & PLANT DISEASE SURVEY BULLETIN 

— <-■▼•- ~~ "■' — ^ n 

STATE/COUNTY/LOCAL GROUPS/U S DEPARTMEMT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 6, May 2, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures . Each individual should check his own fields to deter- 
mine local conditions. 



INSECTS 



FORAGE INSECTS 

Alfalfa weevil development is progressing slowly, but there is a gradual buildup. 
Most alfalfa fields south of Highway 460 are being damaged. In the area between 
Highway 460 and Highway 16, feeding damage is evident; some fields may need treat- 
ment this week or by the following week (May 11) . Between Highway 16 and Highway 17 
larvae can be readily found, but populations are still low. There may be need for 
treatment in some fields in this area in another two or three weeks. 

When checking for alfalfa weevil, judge each field separately; there is a wide varia- 
tion in weevil populations from field to field. If a field is within two weeks of 
harvest, it probably would be best to cut early, remove the hay, and spray the new 
growth. For most fields in the southern section, we will probably get by with a 
single spraying on the first crop, but a second spraying may still be needed on the 
new growth of the second crop. In the central section, early cutting and a spray 
treatment, if needed, on the new growth of the second crop are likely to be sufficient. 
If fields are more than two weeks from harvest and 25 percent or more of the terminals 
show noticeable feeding, spray immediately. 

The insecticide recommendations are: 

1. Commercial applicators can apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) with good results. Use azinphosmethyl only once per cutting. Do 
not harvest for 15 days after treatment with methyl parathion, 16 days for azinphos- 
methyl. Wear protective clothing. 

2. Persons not equipped with protective clothing can use a mixture of (1) 5/4 pound of 
malathion and 3/4 pound of methoxychlor per acre, (2) a mixture containing at least 
1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (5) 1-1/4 pounds of 
malathion per acre on days when air temperatures will be above 60° F. for several 
hours after application. Do not harvest for 7 days after treatment with methoxychlor, 
diazinon, or mixtures of them. There is no waiting period for malathion. 

Clover leaf weevil larvae are numerous in some fields of clover and alfalfa, particularly 
in the western and northern sections of the state. Counts ranged from 4 to as high as 40 
per square foot in some fields. The larvae are about a third grown. Although feeding is 



-2- 

noticeable, damage as yet is slight. Red clover (4 to 5 inches tall) is only about half 
the height of alfalfa (8 to 10 inches tall) and, therefore, most vulnerable. Warm, 
humid weather will allow rapid plant growth and will enhance the spread of a fungus 
disease that kills the larvae. A few cream-colored weevil were observed, indicating the 
possibility of infection by the fungus disease. 

Watch fields closely for the next 10 days. If clover-leaf weevil feeding begins to get 
ahead of plant growth, a spray of 1 pound per acre of malathion will control them. 

Spittlebugs are hatching in northern sections. These tiny orange nymphs are down low 
behind the leaf sheaths. Soon, they will move higher up on the plants and form froth 
masses. They damage alfalfa and clover plants by sucking out the sap. Occasional field 
especially new seedings of red clover, are averaging 1 to 2 nymphs per stem. Damage so 
far is light. In the central and southern sections, froth masses are apparent, but in- 
festations are generally lower than in the north. 

Chemical control is usually not profitable if you find fewer than 1 nymph per stem. If 
treatment is necessary, apply 3/4 pound of methoxychlor per acre. Wait 7 days after 
treatment before pasturing livestock or cutting for feed purposes. 

CORN INSECTS 

Slender seed-corn beetles were numerous in some fields of corn stubble in the northern 
section. In one field the average was as high as 12 beetles per square foot. This 
chestnut -brown beetle (3/8-inch long) --along with the striped seed-corn beetle and seed- 
corn maggot- -will eat holes in the germinating corn seed and cut small sprouts. The 
severity of the problem will depend on weather during the planting period. Cool weather 
and slow germination will enhance the likelihood of damage. Warm weather and more-rapid 
germination will lower the chances for injury. Since aldrin, heptachlor, chlordane, 
lindane, or dieldrin as soil or seed treatments may not control these insects (due to 
resistant problems), we suggest the use of a diazinon seed treatment. A planter treatment 
(7-inch band over the row or just ahead of the press wheel) of Furadan, dyfonate, dasanit 
or phorate (Thimet) at 1 pound of actual chemical per acre- -as suggested for rootworms-- 
will also give adequate protection against these insects. 

Corn borer pupation began in the extreme southern section this week, as reported by 
Bob We the re 11 in Vienna. Stan Ceglinski in Cairo found no borer pupation as yet, so 
spring development is just getting started. Warren Bundy of Edwards vi lie found no 
borer pupation on April 28. 

LIVESTOCK INSECTS 

Horn flies appeared on pastured cattle in the extreme southern sections for the first 
time this week. Populations are light, but an economic buildup (50 to 100 or more per 
animal) could develop within the next two weeks. 

HOMEOWNER INSECT PROBLEMS 

Holly leaf miner larvae can be found tunnelling between the leaf tissues of many types 
of holly. They leave a yellowish mine, and will continue to damage the leaves if not 
controlled. It is still not too late to control them. Use a dimethoate (Cygon) spray 
by mixing 2 teaspoons of the 23-percent (2E) liquid concentrate in a gallon of water. 
Spraying should be done immediately. Thorough coverage is important for good success. 
.Another spraying may be needed about the middle of June. 



-3- 

Sod webworm larvae were reported damaging a few lawns. These were probably larvae that 
overwintered in the soil and have just recently moved to the surface to feed. Only 
occasionally are overwintering larvae numerous enough to cause damage. Actually, not 
even the first-generation webworm larvae in June and July present the major problem; 
rather, the second-generation ones in August. 

Carbaryl (Sevin) , diazinon, or trichlorfon (Dylox) as sprays or granules are effective 
against sod webworms. Follow the instructions on the label relating to dosage, method 
of application, and precautions. 

Crayfish . We were asked what to do about crayfish in low- lying lawn areas where rains 
have been heavy. Our first thought was to stock the lawns with large-mouth bass, if 
conditions are still wet enough; otherwise, wait until conditions dry. The crayfish 
will disappear then. 

Ticks are annoying campers, picnickers, hikers, fishermen, and other persons. They 
cling to the vegetation along paths in and near wooded areas, waiting for man or other 
warm-blooded animals to come along. They attach themselves by embedding their mouth- 
parts into the skin. When entering wooded areas or ones suspected as tick- infested, 
use a repellent on socks, pants, pants cuffs, and exposed parts of the body to prevent 
tick bites. DEET (diethyltoluamide) is one of the best tick repellents. To control 
ticks in the home yard as well as in parks or playground areas, spray the grass, shrubs, 
and flowers with diazinon, malathion, or carbaryl (Sevin) . Do not apply diazinon to 
ferns or hibiscus, malathion to Cannaert red cedar, or carbaryl to Boston ivy. 

You can prevent ants , water bugs , spiders , crickets , and other insects from entering 
your home by spraying the outside foundation wall with a 2-percent chlordane water 
emulsion. Purchase chlordane as a liquid concentrate and mix it with water to the 
proper strength (1 pint of 45-percent chlordane in 3 gallons of water gives a 2 -percent 
solution) . Spray the foundation wall from the soil to the sill area or along the outer 
wall for a distance of about a foot above the soil to the point of runoff. In addition, 
spray 5 to 4 inches of soil adjacent to the wall and the expansion joints along porches 
and steps, plus the edges of walks. In homes with a crawl space, spray the inside wall 
of the foundation and any supporting pillars. Do not spray shrubbery or flowers, be- 
cause the oil in the spray may burn the tender foliage. 

Three gallons of finished spray should do for the average house. The need for using 
insecticides inside the home will be greatly reduced by using this type of outside, 
preventative treatment. 



WEEDS 
INCORPORATING SOYBEAN HERBICIDES 

Most people incorporate herbicides to reduce the surface loss of volatile herbicides. 
Treflan, Planavin, and Vernam are all subject to some surface loss when left exposed 
on the soil surface. Label recommendations for these herbicides have changed during 
the past year. 

Previously, the manufacturer of Treflan suggested that it be incorporated immediately. 
The current recommendation is that incorporation can be delayed as much as four hours 
after application. Weed control may be variable because of delayed incorporation- -if 
the application is made to wet, warm soil or if the wind velocity is 10 m.p.h. or greater. 



For Planavin, the manufacturer suggests that incorporation may be delayed as much as 
two days. If rain should prevent mechanical incorporation, the rain itself will probably 
do the job. Planavin is slightly more soluble and less volatile than Treflan, but in- 
corporation is considered necessary for both. 

Vernam liquid and granular formulations are suggested as preplant incorporated treatments. 
But the granules are also suggested as a preemergence treatment without incorporation. 
Granules will probably reduce volatile loss until rainfall occurs. Slight incorporation 
will probably decrease variability. According to current label suggestions, incorporat- 
ing Vernam is necessary for control of nutgrass, wild cane, or Johnsongrass from seed. 

Dacthal has a low solubility, and will perform more consistently when lightly incorporated 

Amiben, Randox, Lorox, and Lasso are currently recommended for surface preemergence treat- 
ment only. If adequate rainfall does not occur within 10 to 14 days, normal, rotary 
hoeing is suggested. The practice will keep seedling weeds under control, and the slight 
incorporation may improve herbicide performance. 

PASTURE WEED CONTROL 

Many broadleaved weeds in perennial grass pastures can be controlled easily with 2,4-D. 
Timing is an important part of the spray problem in pastures. Most annual broadleaved 
weeds germinate from late April through June. Most are susceptible to 2,4-D when they 
are young and are growing fast. 

Biennial weeds, such as bull thistles, are more susceptible to 2,4-D when they are in 
the rosette stage rather than in the flower-stalk forms. Perennial weeds like Canada 
thistle are most susceptible when they are in the early-bud stage. 

Choose the application rate to fit the problem. In the young stages, most annual weeds 
and dandelions can be controlled with 1/4 to 1/2 pound of 2,4-D per acre. Most other 
pasture weeds can be controlled with a 1- to 2-pound application. Apply 1 to 2 quarts 
per acre of a 4-gallon-per-acre formulation. The high rate will eliminate most legumes 
in a grass -legume pasture. 

If woody or brush species must be controlled, use a mixture of 2,4-D plus 2,4,5-T 
brushkiller. 

Do not spray seedling grasses or grasses that are in the boot to milk stage. Do not 
graze dairy animals on treated areas for 7 days after treatment. 



SPECIAL ANNOUNCEMENTS 



Pesticide Dealers and Applicators' Field Day, 1:30 p.m., May 6, Office of the Grundy 
County Extension Adviser, Kenneth Imig, Watseka. 

Insect and plant disease trouble -shooting will be the general topic, with special em- 
phasis on the alfalfa weevil and corn borer. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

insects: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urb ana- Champaign and Illinois Natural 
History Survey. 

WEEDS: Marshal MoGlamery and Ellery Knake, Department of Agronomy . 

AG COMMUNICATIONS: Del Dahl. 

The information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 




s\ 



COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PL ANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US. DEPARTMEMT OF AGRICULTURE COOPERATING 



SPECIAL NEWS RELEASE 



FOR IMMEDIATE RELEASE 



Diazinon Buildup 
Reduces Seeding Rates 



URBANA--A diazinon seed treatment has been recommended 
for the first time this year to protect germinating corn seeds 
against attack by seed corn beetles and seed corn maggots. 

University of Illinois and Natural History Survey 
Entomologist H.B. "Pete" Petty says the practice is good, but as 
with all new practices, a few problems have resulted. 

Under some conditions--possibly high humidity--corn 
seeding rates have been seriously reduced. Some farmers have been 
forced to replant. The problem occurs when diazinon dust builds 
up under the corn planter plates. 

Petty cautions farmers to remove and examine the plates 
frequently to avoid the buildup problem. And he advises adding 
additional graphite, as they have done in the past, to ensure an 
even flow of seed. 

As an additional precaution, farmers should avoid applying 
more than recommended rates of diazinon. An overdose results in 
extra dust. 

Premixing the powder and seed corn before putting it in 
the planter box also may help prevent the buildup problem. 

-30- 

JTS: je 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMEMT OF AGRICULTURE eOOPETOVpNG 



FOR IMMEDIATE RELEASE 



PEG! 



No. 7, May 9, 1969 



i 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



INSECTS 



FORAGE INSECTS 



Alfalfa weevil development and alfalfa growth have both speeded up this past week. 
Severe feeding was found in many fields below Highway 40, moderate to light feed- 
ing in fields in the central section, and very light feeding in the north-central 
section of the state. Many alfalfa fields have been or will be cut within a week. 

If the first cutting has been removed, be sure to watch the new growth of the 
second crop. If larvae are present and damage is being done, spray immediately. 
In the central part of the state, fields are generally within two weeks of harvest 
and damage is light. Therefore, it would be best to cut early, remove the hay, 
and treat the new growth. Also, if flower buds are present (regardless of how 
much damage the weevil has done) and if the field has not been treated, cut the 
alfalfa, remove it, and spray the second-crop new growth. 

Parasites of the alfalfa weevil were found in some areas of the state in 1968, 
with the parasitism ranging up to 78 percent. Parasites are small wasp larvae 
that hatch-out inside the weevil and feed on it. Again this past week, parasitism 
was found in larvae collected in the southern part of the state. The percent of 
larvae parasitized varied from area to area, but averaged 85 percent around 
Lawrenceville . If fields are more than 2 weeks from harvest and 25 percent of 
the terminals show noticeable feeding, treat them. 

The insecticide recommendations are : 

1 . Commercial applicators can apply 1/2 pound per acre of methyl parathion or 
azinphosmethyl (Guthion) with good results. Use azinphosmethyl only once per 
cutting. Do not harvest for 15 days after treatment with methyl parathion, 
16 days for azinphosmethyl . Wear protective clothing . 

2. Persons not equipped with protective clothing can use a mixture of (1) 5/4 pound 
of malatnion and 3/4 pound of methoxychlor per acre, (2) a mixture containing at 
least 1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 1-1/4 
pounds of malathion per acre on days when air temperatures will be above 60° F. 
for several hours after application. Do not harvest for 7 days after treatment 
with methoxychlor, diazinon, or mixtures of them. There is no waiting period 
for malathion. 



3. Fields that are close to harvest and in which treatment is necessary should 
not be treated with azinphosmethyl (at least 16 days before cutting) or with 
methyl parathion (15 days). Switch to one of the other suggested chemicals, 
such as malathion, that has no waiting period. 

Spotted alfalfa aphids can be found in about any alfalfa field in the state in 
low to moderate numbers . If weather conditions become hot and dry during mid- 
summer, damage could be severe in some fields around late July and early August. 

Clover -leaf weevils are present in most clover fields. But a fungus disease has 
killed many of them in central and southern parts of the state, leaving pale- 
colored, dead larvae hanging from clover leaves or lying on the ground. 

Dead pea aphids can be found attached to clover and alfalfa leaves , as a result 
of being parasitized. 

Spittlebugs are appearing on the stems of alfalfa and clover plants , forming 
froth masses on the stems. 

Chemical control is usually not profitable if you find fewer than 1 nymph per 
stem. If treatment is necessary, apply 3/4 pound of methoxychlor per acre. 
Wait 7 days after treatment before pasturing livestock or cutting the field 
for feed purposes . 

CORN INSECTS 

Corn planting , compared to European corn-borer development , is early in the northern 
two- thirds of the state. Winter populations of corn borer were higher than normal, 
and the survival level is higher than normal. This comparatively early planting 
and the spring borer populations indicate a serious potential problem, unless some- 
thing drastic happens to the corn borer. Pupation began this week, but is still 
averaging less than 10 percent in extreme southern Illinois. Farmers in the 
northern half to two-thirds of Illinois should plan now to take time to examine 
their early planted corn regularly for corn borer, during late June and early 
July. 

Com seed beetles are now found in many cornfields or in fields soon to be planted. 
Anything that hastens germination will help prevent damage by this pest. 

We issued a statement last week about diazinon seed treatment and seeding rates. 
This had nothing to do with germination. However, in some instances, excess dust 
can accumulate in the bottom of the planter box and decrease the seeding rate. 
In some cases, certain hybrid seed has apparently "bridged-over" in the planter 
box and seeded unevenly. In other cases, the dust caked in the planter plates 
and decreased the seeding rate. More trouble was encountered with plastic plates 
than with metal plates . Diazinon as well as other seed treatments can cause 
seeding problems. 

Several corrective measures have been used: (1) Add extra graphite, (2) premix 
the seed, (5) do not overdose, (4) increase the seeding rate, and (5) empty boxes 
and examine planter plates after filling each box. 



-3- 

Above all, watch the seeding rate . 

Pay no attention to rumor and do not panic as some have done. This seed treatment 
is a good practice. As with all new practices, some difficulties will be encountered. 
It will require that a bit more care be taken when planting. Many farmers who have 
examined their planter boxes at regular intervals reported to us that they had no 
problems. Furthermore, many have asked about using diazinon seed treatment and root- 
worm insecticides. Except for BUXten, aldrin, or heptachlor, the rootworm insecticides 
should control these beetles. 

Flea beetles are common in early planted sweet corn in the southwestern part of the 
state. Fields of newly emerging corn should be observed often for these shiny, 
black, jumping beetles. They strip-out narrow lines on the corn leaves, leaving 
only white tissue. If damage is occurring and plants are dying, apply either 3/4 
pound of carbaryl (Sevin)- -preferred on dairy farms --or 1-1/2 pounds of toxaphene 
per acre as a band over the corn row. Also, treat grassy areas bordering the field, 
such as fence rows or ditchs, to prevent additional flea beetles from moving into 
the corn. Do not use carbaryl near beehives or toxaphene near fish-bearing waters. 

HOMEOWNER INSECT PROBLEMS 

Roaches in the home can be controlled with a spray of 0.5-percent diazinon in oil, 
applied to their runways and hiding places . This material can be purchased in a 
pressurized spray can. Also, Baygon was recently approved for use in the home and 
can be purchased in pressurized cans. Brown-banded roaches require a more-thorough 
treatment than the other, more-common species. 

Oystershell scale eggs have begun to hatch, especially on lilac, and the newly 
hatched crawlers are moving out on new growth. Thorough spraying with malathion 
(2 teaspoons of 50- to 57 -percent liquid concentrate per gallon of spray) at this 
time will provide good control of these crawlers. The old scale coverings will 
probably remain on the bark for a while, but they will eventually slough-off. 



WEEDS 
POSTEMERGENCE CORN TREATMENTS 

Although Ramrod is primarily used as a preemergence material at planting time, 
Ramrod wettable powder is cleared for early postemergence spray applications for 
corn until grass weeds reach the two-leaf stage. 

Fairly good results have come in from Agronomy Department trials with this early 
postemergence treatment. But the sooner application can be made after planting, 
the better. Corn tolerance has been good for both preemergence and early post- 
emergence Ramrod applications . 

You don't have to wait until you see the weeds. Ramrod can be applied anytime be- 
fore the weeds or crop emerge. You can still make an application until the weeds 
have two leaves. But don't stretch your luck by applying Ramrod to bigger weeds. 



The very early, postemergence treatment may also provide control of some broad- 
leaved weeds , such as pigweed and lambsquarter . There is no recommendation for 
mixing oil or 2,4-D with Ramrod as an early postemergence treatment. 

The Ramrod -at razine combination has clearance for very early postemergence 
application- -before weeds reach the two-leaf stage. There are no label recom- 
mendations for adding oil to this combination. 

With AAtrex , you have quite a bit of flexibility. If you didn't get it on pre- 
plant or at planting, you can still apply it after planting. But do it before 
the weeds emerge. 

AAtrex may also be used with or without the oil additive as an early postemergence 
spray before weeds are 1-12/ inches hi gh. If the weeds aren't up, there is no 
need to add the oil. Important point : The sooner you apply AAtrex after planting, 
the better. 

When mixing AAtrex and oil, fill the spray tank with at least half the amount of 
water needed. In a separate container, make a thin slurry of AAtrex in water 
and add this to the tank. Keep the suspension well-agitated, add the oil, then 
add the remaining amount of water needed. 

If you plan to use AAtrex and oil, store and handle the oil carefully. Oil con- 
taminated with even a small amount of water may not emulsify properly when added 
to the tank. 

For further details, refer to the University of Illinois 1969 Weed Control Guide, 
and the most-recent label instructions. 

For the best weed control and highest yields, exercise control early. 

HERBICIDE COMBINATIONS FOR SOYBEANS 

We have received several questions about the use of herbicide combinations for 
soybeans . Farmers look to combinations as a way of controlling more broadleaved 
weeds . 

Alanap Plus (Whistle and Amoco soybean herbicide) is a mixture of Alanap and 
Chloro-IPC. The Chloro-IPC improves the smartweed control. 

Dyanap (Alanap + dinitro) is cleared for very early postemergence use on soybeans. 

Dinitro is a contact herbicide that will control most of the broadleaved weeds 
that emerge with the soybeans . Many of the broadleaved weeds continue to emerge 
long after soybeans come up. 

Londax (Lorox + Ramrod) presently is cleared for soybeans, and is to be used for 
seed replanting. 

Noraben , a mixture of Herban (norea) + Amiben, is being advertised before clearance. 
Norea is chemically related to Lorox. It is cleared for cotton, sorghum, and 
spinach, but not for soybeans as yet. 



-5- 

There is also interest in Lorox and Lasso as a preemergence , tank-mix combination. 
The Lorox rate will need to be adjusted for soil type to give a maximum margin 
between soybean tolerance and selective weed control. 

NEW DINITRO CLEARANCE 

Dow has announced that " Preemerge" (dinitro) has been cleared for directed post- 
emergence use on seed soybeans. Dinitro previously had clearance only for use 
on soybeans from the cracking stage- -as plants emerge- -until the first true leaves 
form. Present clearance is for use from the time soybeans are 5 to 6 inches tall 
until they bloom. 

The purpose of this restricted registration is to control some broadleaved weeds, 
such as cocklebur and morningglory , which are tolerant to most preemergence 
herbicides . 



SPECIAL ANNOUNCEMENTS 



Pesticide Dealers and Applicators Field Meetings , 1:30 p.m. each day. May 20... 
Office of the Pulaski -Alexander County Extension Adviser, Stan Ceglinski. 
May 21... Off ice of the Saline County Extension Adviser, Robert Edgar. Insects 
and diseases will be the general topics, with emphasis on the com-borer situation 
and control. 

********** 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Rosaoe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture , Urbana-Champaign and Illinois Natural 
History Survey. 

weeds: Marshal McGlamery and Ellery Knake, Department of Agronomy. 

AG COMMUNICATIONS : Del Dahl. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



Isy^ { 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




;nsect weed & PLANT disease survey bulletin 



iTATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMEMT OF AGRICULTURE COOPERATING^ 



f- , 
. J 



Li. 



r __ 



=0R IMMEDIATE RELEASE 



No. 8, May 16, 1969 



Tiis series of weekly bulletins provides a general look at the insect, weed, and plant 
lisease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
\ocal conditions. 



INSECTS 



■ORAGE INSECTS 

llfalfa weevil populations continue at a high level , and damage is evident in fields south 
»f Highway 16 . In the area between Highway 16 and Highway 136, damage is approaching 
economic levels. Some fields may need treatment this week. North of this line, feeding 
.s noticeable but is not yet severe. Larvae are just beginning to pupate in the central 
iection; pupation is progressing rapidly in the southern sections. However, eggs are 
-.till hatching; so, populations are expected to remain high for another 2 to 3 weeks, 
'.arval populations should now begin to level off and gradually decline, as pupation con- 
:inues and the incidence of parasitism increases. (In several fields, an extreme of 
30 to 95 percent of the larvae were found parasitized by a wasp this week.) 

Continue to watch alfalfa fields in the southern half to two -thirds of the state for 
/eevil problems. In fields that are untreated and as yet uncut, it would be best to cut 
±e alfalfa, remove the hay, and spray the neiv growth of the second crop. Cutting will 
)ften reduce the weevil population, since many eggs are removed and a good many larvae 
ire either killed or forced to pupate by exposure to the sun. If the crop has already 
)een cut but the new growth has not been sprayed, watch it closely for evidence of 
/eevil damage. If it does not green up in 2 to 4 days and if worms are still present, 
ipply treatment promptly. When the second-crop growth is considerable, apply an insec- 
:icide as soon as 25 percent or more of the terminals show noticeable feeding. This 
minly applies to the southern sections of the state. 

.Tie insecticide recommendations are : 

l. Commercial applicators can apply 1/2 pound per acre of methyl parathion or azin- 
phosmethyl (Guthion) with good results. Use azinphosmethyl only once per cutting. 
Do not harvest for 15 days after treatment with methyl parathion, 16 days for 
azinphosmethyl. Wear protective clothing. 

Persons not equipped with protective clothing can use a mixture of (1) 5/4 pound 
of malathion and 3/4 pound of methoxychlor per acre, (2) a mixture containing at 
least 1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 1-1/4, 
pounds of malathion per acre on days when air temperatures will be above 60° F. 
for several hours after application. Do not harvest for 7 days after treatment 
with methoxychlor, diazinon, or mixtures of them. There is no waiting period for 
malathion. 



5. Fields that are close to harvest and in which treatment is necessary should not be 

treated with azinphosmethyl (at least 16 days before cutting) or with methyl parathion 
(15 days). Switch to one of the other suggested chemicals, such as malathion, that 
has no waiting period. 

Use no less than 4 gallons of finished spray per acre by air, or 20 gallons per acre if 
ground equipment is used. On stubble, 10 gallons per acre is sufficient. 

Special note : Some spray burn was noticed this week, but the burn was not serious enough 
to affect yield. The burn appears 2 to 3 days after spraying as yellow spots on the leavt, 

Spittlebug froth masses are numerous in many new seedings of clover and alfalfa, particula: 
in the northern and western sections. If there are 1 or more nymphs per stem, control is 
profitable. It is best to control the nymphs while they are still small and just begin- 
ning to form the froth masses. For control, apply methoxychlor at 3/4 pound of actual 
chemical per acre. With methoxychlor, allow one week to elapse between treatment and 
harvest or pasturing. 

Potato leafhoppers continue to migrate into the state from the south. These tiny, green, 
wedged-shaped insects that skid sideways when disturbed cause a yellowing of the second- 
and third-crop alfalfa. No control measures are needed at this time. 

CORN INSECTS 

European corn-borer pupation is well along in the southern section of Illinois, and a few 
moths have emerged. Pupation is just beginning in the central section. Reports on corn- 
borer development were received this week from Stan Ceglinski at Mounds, Earl Lutz at 
Ridgway, Warren Bundy at Edwardsville, and Jim Paullus at Rochelle. First-generation corn 
borers now have the potential of seriously damaging corn in the northern half to two- 
thirds of the state. Planting got well under way during the last few days of April and 
the first week of May in this area. Rain has since prevented further planting. Corn- 
borer moths will concentrate their egg-laying in these more mature fields (corn, which is 
now up) during the month of June. Watch these fields closely in June for borer infesta- 
tions. Be prepared to use insecticides if needed. 

High overwintering borer populations exist. Thus far, the borers are healthy, although 
strong winds and beating rains during peak moth flights could still eliminate the threat. 

Seed-corn beetles continue to pose a serious threat for germinating corn. The new 
suggestion of using a diazinon seed treatment for protection has presented some problems 
with seeding rates for farmers . The treatment has not affected germination . The earlier 
reports that diazinon dust adversely affected seeding rates have been traced largely to 
the use of the dust during periods of high humidity. This was our suspicion when we first 
commented on this problem two weeks ago. Generally speaking, farmers who have taken the 
time to check and clean their planter plates frequently have had little difficulty. We 
still feel that the use of a diazinon seed treatment is good practice. Some of the farmers 
who have returned their supply of diazinon dust to their dealers may regret this later on. 

Black cutworm moths have been flying for several weeks, but there has been no damage re- 
ported as yet. Cool wet weather favors this insect. Watch low, wet spots or poorly 
drained spots in cornfields for damage. Broadcast applications of aldrin or heptachlor 
at or before planting (not for use on dairy farms) have given the most -cons is tent pro- 
tection against this insect. If damage appears, use a spray- -directed at the base of the 
plants --of carbaryl (Sevin) at 2 or 3 pounds, diazinon at 2 pounds, toxaphene at 5 pounds, 



r trichlorfon (Dylox) at 1 pound of actual chemical per acre. It is best to use at least 
D gallons of water per acre and to cover the spray band by throwing soil at the base of 
~ie plants with a cultivator . 

pm flea beetles could soon be a problem in newly emerging corn. These small, black, 
hiny beetles that jump when disturbed eat white scratch marks on the leaves. Damaged 
lants first turn whitish or silvery, and sometimes are killed. If damage is severe 
ad plants are being killed, apply 3/4 pound of carbaryl (Sevin) or 1-1/2 pounds of toxa- 
dene per acre as a band spray over the row. 

VALL-GRAIN INSECTS 

rue armyworms are present in thick, rank stands of wheat and barley in the southern and 
outhwestern sections of the state. As yet, they are still small and are not numerous 
nough to cause problems. However, the situation will bear watching as more eggs are 
aid and hatch. Cool, wet weather favors this pest. 

o not confuse the striped armyworms with the transparent ye How -to -green sawflies . An 
rmyworm has five pairs of abdominal prolegs ; sawflies, six or more pairs. In many wheat 

ields , we saw more sawflies than armyworms . Sawflies do not damage wheat plants enough 
o require control . 

OMEOWNER INSECT PROBLEMS 

all cankerworms have hatched, and the larvae are beginning to feed on leaves of shade 
rees . This is particularly true in northeastern Illinois. These cankerworms like apple 
r elm, but will also feed on other fruit and shade trees. Sometimes these brown, to 
ark-green, to black measuring worms completely strip trees of their new spring foliage, 
hile other trees may be only partly defoliated. When full grown, the worms drop to the 
round by means of a silken thread that appears like a streamer in the wind. By this 
ime, it is too late for control. For best results, spray the foliage while the worms 
re still small and before the damage becomes severe. Use either 2 pounds of 50-percent 
arbaryl (Sevin) wettable powder or 1 quart of 50- to 57 -percent malathion liquid con- 
entrate per 100 gallons of water. 

awthorn leaf miner maggots will soon disfigure the leaves of Hawthorn trees. They damage 
he leaves by eating the tissues between the upper and lower surfaces . Small brownish 
atches develop along the edge of infested leaves. If your Hawthorn has been bothered by 
eaf miners, spray the leaves now with malathion (2 teaspoons of 50- to 57-percent liquid 
oncentrate per gallon of water) or diazinon (2 teaspoons of 25-percent liquid concentrate 
er gallon of water) . 

lothes moths and carpet beetles are getting ready for a summer's feast on improperly 
tored woolens. A small hole chewed in a piece of clothing may destroy its entire value, 
o keep woolens safe from damage by these insects, follow these suggestions. 

. Dry-clean or wash woolens and place them in clean, plastic storage bags or other insect- 
tight containers . 

. Woolens that are not dry-cleaned or washed should be hung in bright sunlight for a full 
day and brushed thoroughly before storing. Pay particular attention to pocket interiors, 
cuffs, and folds when brushing. 



-4- 

5. If the storage area is not insect-tight (as is true of most closets, trunks, and boxes 
vacuum the container thoroughly and spray all inside surfaces with 0.5-percent diazino 
applied from a pressurized spray can. 

4. Cedar-lined chests are usually insect-tight, but all fabrics need to be insect-free 
before storing. The cedar oil vapors destroy small larvae, but do not kill the larger 
ones. As added insurance in cedar chests, you can spray the inside surfaces as sug- 
gested above or use a fumigant material. Either napthalene or PDB (paradichlorobenzen 
is the fumigant commonly used in moth crystals , flakes , or balls . Use at least 1 poun 
of crystals, flakes, or balls for every 100 cubic feet of space. 

5. Woolens not placed in insect -free containers can be protected by treating in light 
amounts with 0.5-percent diazinon, from a pressurized spray can, or liberally moist- 
ened with fluoride-base fabric solution. Protection will last a year or more, unles 
the woolens are washed or dry-cleaned. Caution: Infants clothing should be washed 
or dry-cleaned before use . 

6. Good housekeeping practices will help reduce the number of these insects. Clean 
frequently to prevent lint and hair from accumulating, especially around radiators, 
baseboards, heating vents, and closets, as well as beneath large furniture and other 
hard-to-get-at places. If these places become infested, a light application of 0.5- 
percent diazinon will insure protection. 

The brown recluse spider was found for the first time in Pike County this week. 

Cereal pr oduct insects may be having lunch in your kitchen cabinets as uninvited house 
guests. Many kinds of beetles and moths attack stored food products. They can be found 
not only in packages or containers of food, but also in the cracks and crevices of cabi- 
nets or cupboards. Follow these three simple steps: 

1. Remove all food packages from the cabinets and examine a small amount from suspect 
packages under a bright light for signs of insects. 

2. Vacuum or carefully brush out cabinets and shelving. 

3. Spray the entire inside surface of the empty cabinets with a 0.5 -percent diazinon or 
5.0-percent methoxychlor-oil solution from a pressurized spray can. 



WEEDS 
CONTROLLING YELLOW NUTSEDGE 

Yellow nutsedge (nutgrass) reproduces from seed, nutlets, and rhizomes. It usually emerge: 
late in damp areas, such as drainageways or low- lying soils. 

Some preplant herbicides help control the weed. Sutan, AAtrex, and Vernam all give some 
control. If you use Vernam on soybeans in late-planted fields, you may be able to deter- 
mine the exact area where application is needed. 

Ramrod and Lasso have both given some control. Lasso appears to be much more active. Las: 
is cleared for preemergence use on both corn and soybeans . 



5 

;:razine and oil will also give control in corn, when applied postemergence to plants that 
re 2 to 3 inches tall. Corn tolerance is lowered with atrazine and with 2,4-D. 

SPECIAL ANNOUNCEMENTS 

;:sticide Dealers and Applicators Field Meetings , 1:30 p.m. each day. 

lay 20. . .Office of the Pulaski -Alexander County Extension Adviser, Stan Ceglinski. 

Iiy 21. . .Office of the Saline County Extension Adviser, Robert Edgar, Harrisburg, Illinois. 

lsects and plant diseases will be the general topics with emphasis on corn borer, armyworms, 
;id flea beetles. 

NOT FOR PUBLICATION 



SPECIAL NOTE TO RADIO AND TELEVISION STATIONS 

3U can have the insect situation report on your station each Friday through Monday noon, 
jlephone (217) 333-2614 each Friday. An automatic answering device will play a recording 
fcth U. of I . entomologists summarizing the week's insect activity and forecasting next 
pek's problems. There is a southern- and northern- Illinois report, each 2 minutes long. 
ou may record either report each time you call. For more information or in case of dif- 
Lculty, call Ron Scherer (217) 333-1130. To get the northern- and southern- Illinois 
ftsect reports call (217) 333-2614, from 6 a.m. on Friday until noon on Monday. 



SPECIAL NOTE TO SPECIALIZED AGRONOMY EXTENSION ADVISERS 

averal weeks ago, you were sent information about the locations of fields of corn stubble 
a your area with high overwintering populations of European corn borers . We need your 
jlp in following the development of corn borer in the state for the next several weeks, 
cten, there are sufficient stalks left exposed, even if the field has been plowed or 
isked. Keep track of the number of larvae, pupae, and empty pupal cases as you dissect 
ie stalks until you count a total of 25 forms. You should be able to do this in 30 
mutes to an hour, if the field still has sufficient borers. If you can get the reports 
lto the mail by Monday or Tuesday of each week, this would be most helpful. 



BAD THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

lis weekly report was prepared as follows: 

LSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen Sturgeon, 
liversity of Illinois College of Agriculture , Urhana-Champaign and Illinois Natural 
Istory Survey. 

ieds : Marshal McGlamery and Ellery Knake, Department of Agronomy. 

"7 COMMUNICATIONS: Del Dahl. 

ie information for this report was gathered by these people, staff members, county Ex- 
2nsion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Lant Pest Control Branch. 



1-/K / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA -CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT, WEED & PLANT DISEASE-SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US DEPARTMEMT OF AGRICULTURE COOPERATING 

IR IMMEDIATE RELEASE 



»..,ia 



No. 9, May 23, 1969 



"% 



is series of weekly bulletins -provides a general look az the insect, weed, and -giant 
sease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
'eviated control measures. Each individual should check his own fields to determine 
<cal conditions . 



INSECTS 



)RAGE INSECTS 

.falfa weevil populations remain high . Moderate to serious damage is evident in untreated 
.elds south of Route 16. Terminal feeding by larvae ranged from 40 to 100 percent in this 
•ea this past week. Damage has reached economic levels in many alfalfa fields between 
>utes 16 and 136. Treatments should be made now or else the hay should be cut and removed, 
.elds between Routes 136 and 24 should be watched closely during the coming week. 

l the extreme southern areas of the state, the number of larvae is gradually leveling off, 
ren declining, as pupation increases and new adults emerge. Parasitism of the larvae by 
isps should also help keep populations in check. 

)ntinue to watch alfalfa fields in the southern two -thirds of the state for weevil prob- 
>ms. If the alfalfa is near cutting, remove the hay and watch the new growth for damage. 

iny fields south of Route 50 have been sprayed at least one time. In some instances, the 
image to the new growth is already extensive with as many as 10 to 20 worms present per 
reep. If the crop has already been cut but the new growth has not been sprayed, watch it 
.osely. If it does not green-up in 2 to 4 days and if worms are still present, apply an 
lsecticide as soon as 25 percent of the terminals show noticeable feeding. 

le insecticide recommendations are: 



Commercial applicators can apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) with good results . Use azinphosmethyl only once per cutting . Do not 
harvest for 15 days after treatment with methyl parathion, 16 days for azinphosmethyl. 
Wear protective clothing. 

Persons not equipped with protective clothing can use a mixture of (1) 3/4 pound of 
malathion and 3/4 pound of methoxychlor per acre , (2) a mixture containing at least 
1/2 pound of diazinon and 1 pound of methoxychlor per acre, or (3) 1-1/4 pounds of 
malathion per acre on days when air temperatures will be above 60° F. for several 
hours after application. Do not harvest for 7 days after treatment with methoxychlor, 
diazinon, or mixtures of them. There is no waiting period for malathion. 

Fields that are close to harvest and in which treatment is necessary should not be 
treated with azinphosmethyl (at least 16 days before cutting) or with methyl parathion 
(15 days). Switch to one of the other suggested chemicals, such as malathion, that 
has no waiting period. 

e no less than 4 gallons of finished spray per acre by air, or 20 gallons per acre if 
•ound equipment is used. On stubble, 10 gallons per acre is sufficient. 



CORN INSECTS 

European corn borer pupation is 75 to 100 percent completed in the southern sections of 
Illinois and moth -emergence is beginning. Egg-laying was observed in a field of early 
planted sweet corn south of Route 13. In the central section, approximately 25 percent 
of the borers have pupated. Pupation is just starting in the northern sections. 

All conditions considered, damage from first -generation corn borers could be serious in the 
northern half to two-thirds of Illinois. Corn borer development is about a week behind, 
compared with last year at this time. Early planted corn in the northern two-thirds of the 
state may be sufficiently mature by mid- to late-June to attract moths and increase corn 
borer survival . 

Flea beetles are damaging occasional fields of corn. Watch newly emerging corn for small, 
shiny, black beetles that jump when disturbed and leave white scratch marks on the leaves. 
If damage is severe and plants are being killed, apply 3/4 pound of carbaryl (Sevin) -- 
preferred on dairy farms--or 1-1/2 pounds of toxaphene per acre as a band spray over the 
row. Many fields being damaged are adjacent to grassy areas, fence rows, roadsides, and 
grass waterways. Spray these to prevent additional flea beetles from moving into the corn. 
Do not contaminate fish-bearing waters when using toxaphene. 

Black cutworms are conspicuous by their absence but can't be written off the books yet. 
Watch the low, wet spots in the cornfields for damage. If damage appears, use a spray 
directed at the base of the plants of carbaryl (Sevin) at 2 or 3 pounds, diazinon at 2 
pounds, toxaphene at 3 pounds, or trichlorfon (Dylox) at 1 pound of actual chemical per 
acre. It is best to use at least 20 gallons of water per acre and to cover the spray band 
by throwing soil at the base of the plants with a cultivator. 

Common stalk borers caused considerable damage last year to border rows in many cornfields. 
Whorl damage by this pest is often observed after it's too late to make a treatment. 

Damage most often occurs to cornfields adjacent to weedy fence rows, ditchbanks , road- 
sides, or grass waterways. These are the places where the common stalk borer overwinters 
in the egg stage. About mid- June, watch for damage to corn whorls by a whitish-brown, 
striped worm with a purple band around the middle . Treatments are not effective unless 
the infestation is spotted early. 

SMALL GRAIN 

True armyworms are being found in thick stands of wheat and barley in the southern half of 
the state. So far, their number is low. Continue to observe wheat and barley fields dur- 
ing the next two weeks. The presence of cool, wet weather is favorable for the development 
of armyworms . 

Treatment is justified if there are six or more armyworms per foot of row as an average 
over the field. Apply 1-1/2 pounds of actual toxaphene per acre for armyworm control in 
small grains. There are no restrictions in use of the grain, but do not feed the straw 
to dairy cattle or to livestock being fattened for slaughter. Do not contaminate fish- 
bearing waters. Avoid drift onto pastures or hay fields. Trichlorfon (Dylox) at 3/4 
pound of actual per acre may be used to within 21 days of harvest, but the straw should 
not be used for livestock feed. Use carbaryl (Sevin) at 1 pound of actual chemical per 
acre on grass pastures or hay fields. Warn area beekeepers when carbaryl is applied. 



-o- 



imy sawflies are being found in wheat fields, but they are of little concern. Do not con- 

ise sawflies with armyworms . The sawf ly larva is transparent and is yellow to green in 

clor. It also has six or more pairs of abdominal prolegs, while the armyworm has five 
firs. 

IMEOWNER INSECTS 

t rope an pine sawflies , a third to a half grown, have been reported at work defoliating 
jne trees. These black-headed, grayish-green larvae like to feed together in clusters. 
Tey can be controlled by spraying with carbaryl (Sevin) using two tablespoons of the 50- 
jrcent wettable powder per gallon of water, or 2 pounds per 100 gallons of water. 



WEEDS 
1STEMERGENCE HERBICIDES FOR CORN 

\ 4-D is the most -economical and effective treatment for most broadleaved weeds in corn. 
Vu can spray over the top until the corn is 8 inches high. On taller corn, use drop 
i zzles (extensions) to keep 2, 4-D out of the corn whorl. 

] sure to apply no more than recommended rate of 2, 4-D. That rate varies with the 
simulation and the strength of formulation (the number of pounds per gallon) . 

Iters are more effective than amines on weeds, so the rates vary. The volatile drift 
lizard is greater with esters than with amines. 

ftme corn hybrids are more susceptible to 2, 4-D injury than others. Some single-crosses 
:;em to be extremely susceptible. Inbred seed stock (parent lines) often are quite 
(Lsily injured. It may be wise to check before spraying. 

hch year some corn is damaged by 2,4-D--1968 was a particularly bad year. Corn is most 
iisceptible to 2, 4-D injury when it is growing fast or when it is under stress. Spraying 
orn with 2, 4-D during or immediately after very cool, wet weather (or during very hot, 
lurid weather) may increase the possibility of corn injury. 

l invel (dicamba) is less likely to injure corn than 2, 4-D, but is much more likely to drift 
ad injure nearby soybeans, vegetables, or ornamentals. Banvel controls smartweed better 
'ian 2, 4-D, but is more expensive. 

ntrex (atrazine) can be applied to corn as a postemergence spray until weeds are 1-1/2 
itches tall. Broadleaved weeds are much more susceptible to AAtrex than annual grass 
[jeds. So for effective grass control, the timing is critical. 

I)ray additives, such as emulsifiable oils or special surfactants, have increased the post- 
uergence herbicidal activity of AAtrex. The spray oil should be low in aromatic content, 
live a high UR value, and should contain at least 1-percent suitable emulsifier--so the 
Ll and water will mix. Agitation is essential to prevent separation of the oil and water. 

se 2-1/2 pounds of AAtrex SOW and 1 gallon of oil in 20 to 40 gallons of water per acre. 
|! sure to add the oil last in the mixing operation. Oil contaminated with water before 
ixing can cause compatibility problems. 

fecial surfactants, such as Tronic or T-Mulz, have also been used with AAtrex. They are 
Ud at a rate of 1 pint per acre or 1 pint per 25 gallons of spray. Surfactants have the 
.'Vantage of having less volume to handle, but oils are usually slightly more effective. 



Under some conditions, AAtrex-oil -water emulsions have resulted in corn injury. Do not use 
oil in AAtrex sprays when the corn is under stress or when it is wet and succulent. Do not 
treat breeding stock or inbred lines with sprays of AAtrex-oil. Do not add 2,4-D to the 
AAtrex -oil -emulsion. 

If AAtrex is applied postemergence at higher than 2-1/2 pounds per acre of 80W, or if it 
is applied later than mid- June, plan to plant corn in the field again next year. Do not 
graze treated areas or feed treated forage to livestock for 21 days following applica- 
tion. 

PLANT DISEASES 
WHEAT 

There is less disease in wheat this year than in any of the past 10 or 15 years. 

Septoria leaf blotch has not spread upward from the lowest leaves. Losses from this diseas 
should be very minor this year. 

Powdery mildew is abundant in scattered fields and will cause lodging and yield reduction. 

Leaf rust should start appearing during the next week or ten days. Trace amounts are now 
present in Arkansas and Missouri . Leaf rust development is later than normal in these 
states, and we anticipate that it will be late in Illinois. 

Loose smut will be evident as the heads emerge from the boot. 

ALFALFA 

Leaf spot diseases are causing defoliation of alfalfa and clovers. Early harvest will 
prevent some leaf loss for this and future cuttings . . 

LAWNS 

Leaf spot and melting -out are common problems, ones that are now serious in some lawns. 
Brown or purple spots are evident on the leaves. Later, the centers become light brown 
and the dark-purple borders are quite distinct. Leaf sheaths are turning brown, causing 
death of the leaf blades and giving diseased lawns a brownish undercast. Later, the crowns 
rhizomes, and roots will turn brown. During hot weather, the plants will die in large 
irregular areas . 

Cultural control practices help keep this disease complex in check. Fungicides such as 
Ortho Lawn and Turf Fungicide, Daconil 2787, Dyrene, defolatan, folpet (Phaltan) , maneb 
(Fore), or zineb are effective when applied on a regular, protective schedule. But they 
will do little good now if leaf spot and melting-out are severe. 

Stripe smut is prevalent and is serious in scattered turf areas. Look for pale-green to 
yellowed plants occurring in patches. Infected plants are stunted and have curled or 
shredded leaves with black stripes. Such plants will probably die during the hot, dry 
weather. 

At present, about all we can suggest is to water and fertilize heavily infected lawns. 
These practices promote vigor and help keep smutted plants aliveT If smut is a minor 
problem (only a few scattered plants that are difficult to see), let the lawn dry out. 
The smutted plants will die and healthy plants will then replace them. 



IP 



-5- 

FRUIT 

Peach leaf curl is serious and is causing almost complete defoliation of unsprayed trees 
in backyards . All we can suggest is to fertilize and water during dry periods, to promote 
vigor and a new crop of leaves. The disease is easily controlled by a single, dormant 
application of almost any fungicide. 

Fire blight is showing up on apple, pear, crabapple, hawthorn, and related plants. See 
Report on Plant Diseases No. 801 for more details. 

Apple scab is now serious on apple and crabapple . Infected leaves are turning yellow and 
are dropping off. Many trees will be nearly defoliated during the next several weeks 
where a protective spray program is not followed. 



SPECIAL ANNOUNCEMENTS 



Pesticide Dealers and Applicators Field Days/1: 30 p.m. each day: 

June 3, Office of the Perry County Extension Adviser, Charles Howell, Pinckneyville 

June 4, Office of the White County Extension Adviser, Ralph Romig , Carmi 

June 9, Office of the Jasper County Extension Adviser, Larry Casey, Newton 

June 10, Office of the St. Clair County Extension Adviser, Ray Hardimon, Belleville 

June 10, Office of the Marion County Extension Adviser, Les Rogers, Salem 

June 11, Office of the Macoupin County Extension Adviser, William McAllister, Carlinville 

June 11, Office of the Moultrie County Extension Adviser, Roger Wenberg, Sullivan 



NOT FOR PUBLICATION 



SPECIAL NOTE TO RADIO AND TELEVISION STATIONS 

You can have the insect situation report on your station each Friday through Monday noon. 
Telephone (217) 333-2614 each Friday. An automatic answering device will play a recording 
with U. of I. entomologists summarizing the week's insect activity and forecasting next 
week's problems. There is a southern- and northern- Illinois report, each 2 minutes long. 
Ifou may record either report each time you call. For more information or in case of dif- 
ficulty, call Ron Scherer (217) 333-1130. To get the northern- and southern-Illinois 
insect reports call (217) 333-2614, from 6 a.m. on Friday until noon on Monday. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Rosooe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural 
'iistory Survey. 

'WEDS: Marhsal MoGlamery and Ellery Knake, Department of Agronomy. 

plant DISEASES: M.C. Shurtleff and M.P. Britton, Department of Plant Pathology. 

\G COMMUNICATIONS: Del Dahl. 

the information for this report was gathered by these people, staff members, county Ex- 
:ension advisers, and others, in cooperation with the USDA Agricultural Research Service, 
^lant Pest Control Branch. 



Jft /-. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/U S DEPARTMEMT OF AGRICULTURE COOPERATING 

L... 



OR IMMEDIATE RELEASE 



: , 



No. 10, May 29, 1969 



Ttis aeries of weekly bulletins -provides a general VtMMi at the insect, weed, and -giant 
liaease situation (fruit and commercial vegetables excepted), along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



VRN INSECTS 

ieed-corn beetles and seed-corn maggots are both damaging germinating corn. The beetles 
ire also hurting seedling plants. Missing plants (skips) or stunted plants are a sign of 
;eed damage by these insects. The slender seed-corn beetle (most common) is chestnut 
)rown color. The striped seed-corn beetle is dark-brown with a tan border. Both are 
ibout 3/8 inch long and move about in the soil readily. The seed-corn maggot is a pale, 
/ellowish-white maggot about 1/4 inch long found in the seed. 

fhe beetles and maggots eat holes in the seed. The beetles also eat gouges in the devel- 
oping sprout, sometimes cutting small sprouts completely. Plants with damaged sprouts or 
dnor tunnelling in the seed are stunted. Many of these plants will still recover. Once 
:orn reaches the three- or four-leaf stage, it will usually grow away from the damage. 
lowever, the insects will continue to hurt germinating corn for another 2 to 4 weeks. 
Damage is evident in untreated fields as well as in fields treated with aldrin, heptachlor, 
Alordane, lindane, or dieldrin as seed or soil treatments, indicating resistance to these 
insecticides. The control of these insects has been satisfactory, when a diazinon seed 
treatment or an insecticide for resistant rootworms was applied at planting time. 

If replanting becomes necessary, use a diazinon dust on the seed for control. Take time 
to check and clean the planter plates frequently. This will help prevent any reduction 
in the seeding rate. 

Slack cutworms are reported to be causing damage in a few fields. Watch the low, wet 
spots in the cornfields. If damage appears, use a spray directed at the base of the 
Dlants of carbaryl (Sevin) at 2 or 3 pounds, diazinon at 2 pounds, toxaphene at 3 pounds, 
)r trichlorfon (Dylox) at 1 pound of actual chemical per acre. It is best to use at 
least 20 gallons of water per acre and to cover the spray band by throwing soil at the 
)ase of the plants with a cultivator. 

European corn-borer moth emergence is progressing rapidly in the southern section. In 
the central section, approximately 75 to 90 percent of the borers have pupated, and 
emergence of moths is beginning. Pupation has started in the northern section, but no 
noths have emerged as yet. Corn-borer development parallels that of 1956, when a high 
overwintering population caused severe damage in the more -mature plantings in late June 
aid early July. Much of the corn planted before May 10 in the northern half to two- 
thirds of the state (except localized areas in the east-central section) may develop 
pconanic infestations of first-generation borers. Watch fields in the south-central 
'section beginning about June 12, in the central section about June 18, and in the 
northern section about June 24 for damaging infestations. Plan to use insecticides if 
leeded. 






-2- 

Grape colaspis is damaging occasional fields of corn planted on a plow down of red clover, 
according to late reports. These small white grubs chew off the root hairs. Row treat- 
ments of aldrin or heptachlor do not provide adequate protection against this insect, but 
broadcast treatments are effective. Affected plants are stunted and the leaves turn purp] 
indicating a lack of phosphate due to the inability of the damaged roots to absorb a suf- 
ficient amount. The grubs will mature and complete their feeding during the next two to 
three weeks. Generally, plants will recover and produce a near-normal yield unless the 
damage is extremely severe. 

CORN AND SOYBEAN INSECTS 

White grubs have been reported as numerous in a few fields now being plowed in the centra] 
section. These are mainly fields in a continual corn-soybean rotation. The grubs are 
generally large, indicating that this is the last year of their cycle. These large grubs 
will finish feeding in mid to late June and will burrow down in the soil to form the rest- 
ing (pupal) stage. Next year about this time, the adult June beetles will emerge and lay 
eggs in soybean or sod fields to complete the cycle. 

If the field is to be planted to soybeans, a delay in planting to allow the grubs to finis 
their feeding period will be helpful. If the beans have already been planted, nothing can 
be done. 

Before planting corn, broadcast 2 pounds of actual aldrin or heptachlor per acre and disk 
it in. After corn is up, it might help to spray 1 pound of actual aldrin or heptachlor 
per acre. Direct the spray at the base of the plants. Cultivate immediately to throw 
soil over the sprayed band. This will provide some help but will not be perfect. Rain 
following treatment will improve control. Corn treated in the same manner should not be 
used for ensilage or stover, but it may be used safely for grain. Do not make treatments 
after July 1. Do not use aldrin or helptachlor on dairy farms. 

FORAGE INSECTS 

Alfalfa weevil populations are beginning to level off and decline as the larvae pupate. 
Parasites take their toll, and adults lay fewer eggs. The problem area lies south of 
Route 9. 

Watch the new growth of the second crop. If it does not green-up in 2 to 4 days after 
cutting, and if worms are present, spray it promptly. When the second-crop growth is con- 
siderable, apply an insecticide as soon as 25 percent or more of the terminals show no- 
ticeable feeding. (This applies mainly to the southern third of the state.) Larvae of 
the alfalfa weevil will be present and easily found for several weeks yet, but the peak 
period for damage is over in most areas. 

For control of the alfalfa weevil larvae, farmers making their own applications should 
use malathion or a commercially prepared malathion-methoxychlor or methoxychlor-diazinon 
(Alfatox) mixture. Commercial applicators can use the above materials or one of the 
more-toxic insecticides like methyl parathion or azinphosmethyl (Guthion) . Be sure to 
follow label directions for dosages, harvest limitations, and precautions when using in- 
secticides . 

Lesser clover- leaf weevil larvae can be found feeding behind leaf sheaths and along the 
stems of red clover. The larvae are gray to dirty-green, legless worms with a black 
head. They can usually be found in a dirty groove on the stem or in a tunnel inside the 
stem behind a leaf sheath, or in terminal buds. Infested plants are often stunted, and 
stems and leaves may wilt and die. The blooms dry-up and turn brown prematurely. No 
practical control measures are known. 



OMEOWNER INSECT PROBLEMS 

t 

, agworm hatch is about complete in the southern sections, and sprays should be applied im- 
! ediately. The target date for spraying in the central sections is after June 15; in the 

orthern sections, after June 30. Bagworms especially like to feed on evergreens (except 

ews) , but they will also attack other trees and shrubs. 

ake plans to apply treatments early this year, xvhile the worms are still small and easy 
o kill and before damage is evident. Carbaryl (Sevin) , diazinon, or malathion are all 
ffective. Malathion will also provide fair control of the mites that may be present, 
j ollow label directions and check the list of plants on the label for the ones that may be 
njured if sprayed with the insecticide you are using. 



.phids are heavy on many kinds of trees, shrubs, and flowers. These small, soft -bodied, 
ucking insects (green, yellow, black, or red) secrete a sticky material called "honeydew." 
his sugary secretion coats leaves, making them glisten. Cars parked beneath infested 
rees become covered with sticky spots. Ants are often numerous on aphid- infested plants, 
here they feed on the aphid secretions. 

hite specks are usually visible on the leaves; these are the cast-off skins of the aphids-- 
iOt eggs. The leaves of heavily infested plants will curl, yellow, and eventually brown. 

; or control, spray the foliage thoroughly, using 2 teaspoons of 50- to 57-percent mala- 
Mon or a 25-percent diazinon emulsion concentrate per gallon of water. Do not use mala- 
:hion on African violets or cannaert red cedar. Do not use diazinon on ferns or hibiscus. 

iuonymous scale crawlers are now moving out on the leaves and new growth. They will soon 
: orm a protective covering, making control difficult. If your euonymous has a history of 
icale problems, apply a malathion spray immediately. Repeat the treatment twice more at 
/eekly intervals. To mix, use 2 teaspoons of the 50- to 57-percent malathion liquid con- 
:entrate per gallon of water. 

lie " dive bombers" are back again. There are a large number of mosquitoes in many areas, 
irobably as a result of the wet weather during recent weeks. To reduce the number of mos- 
luitoes in home yards, follow these steps: (1) Eliminate standing water in such places 
is eave troughs, old tires, tin cans, childrens' toys, storm sewers, etc. (2) Apply a 
/ater-base spray containing 1-percent malathion (2 ounces of 50- to 57-percent liquid con- 
:entrate per gallon of water) to shrubbery and tall grass. Repeat the treatment every 
;eek or two if needed. (5) Keep the screens on doors and windows in good repair. (4) Hang 
)lastic resin strips (2" x 10") containing 20-percent dichlorvos (DDVP)--one strip per 
L,000 cubic feet of space, or about one per room. These strips will kill mosquitoes and 
•lies for 4 to 6 weeks. As an added precaution, hang the strips where children cannot 
'each them and away from fish bowls and food counters. A 0.1 -percent pyrethrum space 
;pray- -applied from a pressurized spray can- -can be used for quick knockdown in place of 
:he dichlorvos resin strips. Frequent treatments will be needed during problem periods. 
^5) When entering mosquito- infested areas, use a repellent. One of the most -effective 
rosquito repellents is DEET (diethyltoluamide) . (6) For quick knockdown at cookouts, out- 
loor parties, or picnics, use either 0.1-percent pyrethrum or 0.5-percent dichlorvos 
(DDVP) as an oil- or water-base space spray. Spray the mist lightly beneath tables and 
:hairs and into the air for a few feet around the area. Repeat the treatment as needed. 

Tie number of fleas on dogs and cats is increasing. If left uncontrolled, they can be- 
:ome a serious problem in a home or home yard by late summer. The worm (larva) stage _ 
3f fleas live in the bedding of dogs and cats, rugs, upholstered furniture, and even in 
:he dirt in flower and shrubbery beds. The worm stage is usually not noticed and is 
larmless, but adult fleas suck the blood of warm-blooded animals. Your dog or cat is a 



-4- 

walking bait station for fleas. Dust them at least once a month during the warm weather 
(May to October) with either 4-percent malathion or 5-percent carbaryl (Sevin) . Treat- 
ments should also be made once or twice during the colder months (November to April) for 
added protection. 



WEEDS 
POSTEMERGENCE TREATMENTS ON CORN 

Four points seem timely: 

1. Atrazine and oil applications need rain soon after application to be highly effective. 

2. We've had several calls regarding the control of nutgrass in corn. Atrazine and oil 
does the best job. If you're willing to risk corn injury—where you have a serious 
nutgrass problem, you can add 2,4-D to the atrazine and oil. Keep in mind that the 
practice is risky, and if you try it, you're gambling and may suffer some corn injury . 

3. We have a report from Minnesota researchers that adding one-half pound of Dowpon to 
atrazine and oil activates the atrazine and improves grass control. Dowpon is cleared 
for such use, but our tests have not shown much improvement in control by adding the 
Dowpon. 

4. Where grasses are coming, consider using the rotary hoe. It's still a good way to 
kill existing weeds, and the light incorporation sometimes improves herbicide activity 

WATCH YOUR WELL 

We've had several calls from farmers who have filled their spray tanks, and then had the 
tank's contents siphoned back into the well- -herbicide and all. 

Remove the hose when you finish filling the tank. Better yet, be certain you have a valve 
that will prevent siphoning. Another way to avoid the accident is to fasten the hose to 
the top of the tank, so that it doesn't extend into the spray tank. 



SPECIAL ANNOUNCEMENTS 



Pesticide Dealers and Applicators Field Days/1: 30 p.m. each day: 

June 3, Office of the Perry County Extension Adviser, Charles Howell, Pinckneyville 

June 4, Office of the White County Extension Adviser, Ralph Romig, Carmi 

June 9, Office of the Jasper County Extension Adviser, Larry Casey, Navton 

June 10, Office of the St. Clair County Extension Adviser, Mike Hardimon, Belleville 

June 10, Office of the Marion County Extension Adviser, Les Rogers, Salem 

June 11, Office of the Macoupin County Extension Adviser, William McAllister, Carlinville 

June 11, Office of the Moultrie County Extension Adviser, Roger Wenberg, Sullivan 



NOT FOR PUBLICATION 



SPECIAL NOTE TO RADIO AND TELEVISION STATIONS 



You can have the insect situation report on your station each Friday through Monday noon. 
Telephone (217) 335-2614 each Friday. An automatic answering device will play a recording 
with U. of I. entomologists summarizing the week's insect activity and forecasting next 
week's problems. There is a southern- and northern- Illinois report, each 2 minutes long. 



jiu may record either report each time you call. For more information or in case of dif- 
jculty, call Ron Scherer (217) 333-1130. To get the northern- and southern- Illinois 
; sect reports call (217) 333-2614, from 6 a.m. on Friday until noon on Monday. 



[ AD THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

; is weekly report was prepared as follows: 

.SECTS: H.B. Petty, Steve Moore, Rosooe Randell, Bon Kuhlman, and Stephen Sturgeon, 
liversity of Illinois College of Agriculture , Urbana-Champaign and Illinois Natural 
> story Survey . 

•EDS: Marshal MoGlamery and Ellery Knake, Department of Agronomy. 

|: COMMUNICATIONS: Del Dahl. 

he information for this report was gathered by these people, staff members, county Ex- 
nsion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
'ant Pest Control Branch. 



J .'H '/ 



\( 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT, WEED & PLANT DISEASE .SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US DEPARTMEMT OF AGRICULTURE COOPERATING 






FOR IMMEDIATE RELEASE 



USRARY 



No. 11, June 6, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures. Each individual should check his own fields to deter- 
mine local conditions. 



INSECTS 



CORN INSECTS 

Seed-corn beetles are still present in many cornfields throughout the state. Where a 
diazinon seed treatment was not used, damage may yet occur to newly emerging corn 
plants. If replanting is necessary or if the corn is just now going in, be sure to 
treat with diazinon. Corn now 6 inches high or taller will probably escape further 
damage by the beetle. 

The slender seed-corn beetle is migrating now and was picked up in light traps by the 
thousands this past week. Damage caused by the seed beetle may appear in fields, but 
the beetle could be gone. 

True armyworms have been reported doing damage to corn following rye where a no-tillage 
system of planting was used. The armyworm moths laid eggs in the rye, and the newly 
hatched worms are feeding on the corn. For control, use 1-1/2 pounds of toxaphene, 
1-1/2 pounds of carbaryl (Sevin) , or 1 pound of trichlorfon (Dylox) --applied as a spray 
over the row when damage is apparent. Cultivating after application will be helpful. 

Wireworms are damaging corn in a few fields where no insecticide had been used. If 
replanting is necessary, apply a broadcast application of 2 pounds of aldrin or hep- 
tachlor per acre, and disk-in immediately. A spray may give quicker kill than the 
granules. It is difficult to control this insect after corn is planted. Use a spray 
of aldrin or heptachlor to salvage a damaged stand where replanting is unnecessary 
and to prevent further damage. Apply 1 pound of the actual chemical per acre. Direct 
the spray at the base of the plant and cultivate immediately. Do not use aldrin or 
heptachlor on dairy farms- -try diazinon. 

Corn rootworm eggs of both the western and northern species will begin to hatch within 
another week or two. Potentially, fields of continuous corn in the northern half of 
Illinois may be affected. Many fields of second-year corn north and west of a line 
from Dixon to Peoria to Stronghurst may be damaged by the western corn rootworm . 
Other fields of second-year corn to the east and north of this line may also be dam- 
aged. The northern corn rootworm is most abundant north of Highway 36 (Pittsfield 
to Springfield to Decatur), and is often a problem in fields where corn has been 
grown continuously for three or more years in the same field. 



If you suspect or know that you have a resistant western or northern corn-rootworm 
problem, and if you did not use an organic phosphate or carbamate insecticide at 
planting time, apply one of these within the next two weeks. Use granules applied 
at the base of the com plants, and cover them by cultivation. A special applicator 
on the cultivator directs the phosphate granules at the base of the plant, and dirt 
is thrown over this deposit. 

Organic phosphate or carbamate insecticides are the only effective means of con- 
trolling resistant rootworms. The following materials have label approval for basal 
application and are recommended for control of resistant rootworms in Illinois. 

Rate per 

Insecticide acre (lb.) 

*BUXten 1 

Diazinon 1 

Disulfoton (Disyston) 1 

Parathion (Niran) 1 

Phorate (Thimet) 1 

Carbaryl (Sevin) 2 

*Note: Effective June 1, 1969, BUXten 
granular has been granted USDA 
registration for use as a basal 
application for corn rootworm 
larval control in field corn. 
For best results, make the ap- 
plication before June 15. 

The emergence of European corn borer moths is almost complete in the southern section. 
In the central section, pupation is complete and moth emergence is well underway. 
Pupation is about 90 -percent complete in the northern section and moth emergence is 
just starting. 

Egg- laying has been observed south of Route 50. These early counts show 55 to 65 
egg masses per 100 plants. An estimated 10 to 15 percent of the pupae in old stalks 
in the southern section have been killed by sunscald. In southern areas, egg-laying 
will take place for another 10 days to two weeks. 

Watch closely for damage in fields that were planted very early . Fields averaging 
30 inches in height now, with a tassel ratio of 5 to 10, may have a high level of 
borer survival and could warrant treatment within two weeks, or perhaps sooner. The 
survival of borers from eggs layed during the next two weeks will increase with corn 
plant development. Economic damage may be prevented if we get hot, dry winds, which 
will roll the egg masses off plants. Hard, beating rains would also help kill the 
moths during peak egg- laying periods. Moths may be laying eggs on weeds and other 
plants, and this would further reduce economic damage. 

r!uch of the com planted before May 10 in the northern half to two-thirds of the 
state (except for localized areas in the east-central section) may develop economic 
infestations of first-generation borers. Watch fields for damaging infestations... 
in the south-central section beginning about June 12, in the central section about 
June 18, and in the northern section about June 24. Plan to use insecticides if 
needed. 

To decide whether an insecticide can be profitably applied, measure the tassel 
ratio of the field and determine the percentage of the plants with recent feeding 
in the whorl leaves. To determine the tassel ratio, measure the height of the 



-J- 



plants with leaves extended; split the stalk open and measure from the tip of the 
developing tassel to the base of the plant; divide the tassel height by the plant 
height; and multiply by 100. That figure is the tassel ratio. If the tassel ratio 
is at least 55 (preferably 40 to 45) and at least 75 percent of the plants show whorl 
feeding, treatment is justified. Use 1 pound of actual diazinon in granular form per 
acre or 1-1/2 pounds of carbaryl (Sevin) as granules. For spraying, use the same 
amount of actual insecticide per acre, and direct the spray to the upper third of the 
plant. Aerial applications should be granules, not sprays or dusts. Allow JO days 
between treatment and the ensiling of corn when applying diazinon; carbaryl has no 
waiting period. Commercial applicators may prefer to use parathion, which provides 
good control of the corn borer. Parathion has a 12-day waiting period between treat- 
ment and harvest. 

Corn flea beetles are appearing, but their number remains low except in an occasional 
field. They can damage stands when the population is high. Both the black beetles 
have been observed on small corn. If damage to newly emerging corn is severe and 
plants are being killed, apply 5/4 pound of carbaryl (Sevin) --preferred on dairy farms - 
or 1-1/2 pounds of toxaphene per acre as a band spray over the row. They inflict 
white scratch marks on the first 5 or 4 true leaves and may cause the seedling to ap- 
pear whitish or silvery. Do not contaminate fish-bearing waters when using toxaphene. 

Black cutworm problems have been few thus far. Although damage is more likely to 
occur in low, wet spots, these cutworms may attack on hillsides too. Check the low 
spots in cornfields regularly; watch for missing, cut, or wilting plants. The small, 
gray-to-black worm can usually be found in the soil near the damaged plant. Corn 
plants cut above the growing point or heart will recover. 

If damage appears, use a spray directed at the base of the plants of carbaryl (Sevin) 
at 2 or 5 pounds, diazinon at 2 pounds, toxaphene at 5 pounds, or trichlorfon (Dylox) 
at 1 pound of actual chemical per acre. It is best to use at least 20 gallons of 
water per acre; also, to cover the spray band by throwing soil at the base of the 
plants with a cultivator. 

If you know the location of a black cutworm problem field, please contact us . 

Thrips can be found in the whorl of all corn plants in southern Illinois. Their 
feeding appears as tiny streaks of white mottling on the leaves. When thrips are 
abundant, the damage may give the field a wilted, silvery appearance. Do not con- 
fuse thrip damage with the silvery colored upper corn leaf damage caused by wind or 
cold. Insecticides are seldom needed to control thrips on corn. There arc two 
species; the adult of one species is yellow and white, the other is black. Fully 
grown adults are about 1/16 of an inch long. 

Corn blotch leaf miners are appearing in cornfields around the southern areas. The 
adult lays eggs in the surface of the corn leaf. The larvae leave mines, or trans- 
parent galleries. The feeding and egg-laying punctures made by the adult (a gray- 
to-brown fly) probably have little effect on plant vitality. Likewise, the leaf 
mining by the larvae seldom causes injur)'. 

SMALL GRAIN 

True armyworm populations continue to remain low in most thick, rank stands of small 
grains (wheat , barley, rye, grasses) throughout the southern half o\~ the state. It 
is advisable to make spot checks in small grain fields for another two weeks. Cool, 
wet weather is favorable for the development of nrmyworms. 



-4- 

Treatment is justified if there are 6 or more armyworms per foot of row as an average 
over the field. For control, apply 1-1/2 pounds of actual toxaphene per acre. There 
are no restrictions on the use of the grain, but do not feed the straw to dairy cattle 
or to livestock being fattened for slaughter. Do not contaminate fish-bearing waters. 
Avoid drift onto pastures or hay fields. Trichlorfon (Dylox) at 3/4 pound of actual 
chemical per acre may be used to within 21 days of harvest, but the straw should not 
be used for livestock feed. Use carbaryl (Sevin) at 1 pound of actual chemical per 
acre on grass pastures or hay fields. Warn area beekeepers when carbaryl is applied. 

FORAGE INSECTS 

Alfalfa weevil larvae populations are declining in the southern part of the state, as 
pupation increases and adults emerge, In the central and north- central sections (be- 
tween Route 36 and Route 34) , larvae are causing economic damage to many fields of 
first-crop alfalfa. In this area, it is best to cut and remove the hay; then watch 
the new growth for damage. 

Some serious larval damage to the new growth of the second crop has been reported 
south of Route 50. If the new, second-crop growth does not green-up within 2 to 
4 days after cutting, look for the small, green larvae or the 1/4 inch, brown-snout 
beetle adults of the alfalfa weevil. Treat promptly if either or both are present 
and if 25 percent or more of the terminals show feeding. Adult feeding damage, 
which appears as a "feathering" along leaf margins, may occur in the extreme southern 
areas as the pattern of emergence increases . 

For control of the alfalfa weevil larvae, farmers making their own applications 
should use malathion or a commercially prepared malathion-methoxychlor or methoxychlor- 
diazinon (Alfatox) mixture. Commercial applicators can use the above materials or 
one of the more-toxic insecticides, such as methyl parathion or azinphosmethyl (Guthion) . 
Be sure to follow the label directions for dosages, harvest limitations, and precautions 
when using insecticides . 

HOMEOWNER INSECT PROBLEMS 

Bagworms are hatching in southern sections. Sprays should be applied immediately. In 
the central sections, the target date for spraying is after June 15; in northern sections 
after June 30. 

For best results, spray while the worms are still small and easy to kill--and before 
damage is evident. Use either carbaryl (Sevin), diazinon, or malathion. The latter 
will also provide fair control of any mites that are present. Follow the recommenda- 
tions on the label, and check the plants that may be injured by the particular insecti- 
cide being used. 

Leaf miners are feeding between the upper and lower surfaces of the leaves on some 
birch trees, leaving blotches and "mines." For control, spray the foliage thoroughly 
when the mines first appear. Use diazinon (4 tablespoons of diazinon 25-percent E.C. 
in 6 gallons of water) or malathion (4 tablespoons of malathion 50- to 57-percent E.C.). 
Repeat the treatment in 10 to 12 days. 

Elm leaf beetles will soon be skeletonizing the leaves of Chinese elm. Other elm 
species are also affected to some extent. These are small, dirty-yellow to black 
worms found on the undersides of the leaves. A spray of carbaryl (Sevin), using 
2 pounds of 50-percent wettable powder per 100 gallons of water, or lead arsenate, 
using 4 pounds of wettable powder per 100 gallons of water, is effective. 



-5- 

Maple bladder galls can be found on the upper sides of the leaves on some soft maple 
trees . These show up as green or reddish growths. Mites overwintering on the bark 
of trees stimulate the formation of the galls, in which many mites live and feed. 
These galls rarely cause damage. It is too late to control this insect in 1969. 
Next spring, spraying with malathion after the buds are swollen but before new leaves 
appear will control this pest. 

Oystershell scale hatch is underway in the central and southern parts of Illinois. 
The new crawlers are getting ready to begin feeding on lilac, birch, dogwood, ash, 
peonies, and many other shade trees and shrubs. In the northern sections, it will 
be about 2 weeks (June 15) before hatch is complete. For control, use a spray of 
malathion (2 teaspoons of 50- to 57-percent concentrate per gallon of water), and 
treat the infested area thoroughly. An additional treatment may be needed in mid- 
August for the second-generation crawlers. Even though scales are killed by spraying, 
the covering will persist for several months. 

Forest tent caterpillars are pale blue worms with a white keyhole marking on each 
segment down the back. These worms make no tent or extensive webbing, but they can 
quickly defoliate trees. Carbaryl (at 2 pounds of 50-percent wettable powder per 
100 gallons of water) will give control. 

The brown recluse spider was found for the first time in Franklin County this week. 



WHEAT DISEASES 



Glume blotch is beginning to appear on wheat heads. On the Ben Hur variety, glume 
discoloration occurs naturally and should not be confused with glume blotch. 

Loose smut is also present in wheat, as is head blight or scab. 

SPECIAL ANNOUNCEMEFTTg 
Pesticide Dealers and Applicators Field Days/1: 30 p.m. each day: 

June 9, Office of the Jasper County Extension Adviser, Larry Casey, Newton. 

June 10, Office of the St. Clair County Extension Adviser, Mike Hardimon, Belleville. 

June 10, Office of the Marion County Extension Adviser, Les Rogers, Salem. 

June 11, Office of the Macoupin County Extension Adviser, William McAllister, Carlinville, 

June 11, Office of the Moultrie County Extension Adviser, Roger Wenberg, Sullivan. 

June 17, Office of the Brown County Extension Adviser, Robert Hayward, Mt. Sterling. 

June 17, Office of the Henderson County Extension Adviser, Curt Eisenmayer, Stronghurst. 

June 18, Office of the Knox County Extension Adviser, Don Teel, Galesburg. 

*June 18, Office of the Livingston County Extension Adviser, Paul T. Wilson, Pontiac. 

*June 19, Office of the McLean County Extension Adviser, Gene Mosbacher, Bloomington. 

June 19, Office of the Iroquois County Extension Adviser, Ken Imig, Watseka. 

*NOTE : THE DATES OF THE LIVINGSTON AND MCLEAN COUNTY MEETINGS HAVE BEEN CHANGED FROM 
PREVIOUS ANNOUNCEMENTS. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty t Steve Moore, Rosooe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural 
History Survey. 

diseases: M.P. Britton, Department of Plant Pathology. 

AG COMMUNICATIONS: Del Dahl. 

The information for this report was gathered by these people, staff meirbers, county Ex- 
tension advisers, and others, in cooperation with the USDA Agricultural Research Servio 
Plant Pest Control Branch. 



"** I 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
U R B AN A-CH AM P Al G N 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



rATE/COUNTY/LOCAL GROUPS/U S. DEPARTMEMT OF AGRICULTURE COOPERATING 



3R IMMEDIATE RELEASE 






l<& 



: 



2 









No. 12, June 13, 1969 



his series of weekly bulletins provides a general look at the insect, weed, and -plant 
Isease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine local 
editions . 



INSECTS 



DRN INSECTS 

ged-corn beetle damage is still being reported to us. Plant stands are erratic, and plants 
ary greatly in size. Since these beetles have eaten the food stored in the seed, the small 
prout dies before it emerges; or if it does emerge, the seedling is weakened. Therefore, 
lere are normal plants in the field, weak plants less than half normal size, plants that 
ave never emerged, and seeds that did not germinate. Variation in size can also be due to 
ertilizer burn, wind, fungus infection, and planting -depth differences. However, if the 
eed was definitely hollowed out, the damage is probably seed beetle. Seed-beetle damage 
as been observed where no treatment was applied, as well as where aldrin or heptachlor 
ad been used as soil insecticides . 

arn blotch leaf miners are becoming more common. They are not of economic importance, but 
an be confused with other problems. The adult, which is a fly, makes tiny elongated punc- 
ures in groups about 1/16-inch long- -usually in the tip of the leaf. The maggot mines 
stween the upper and lower leaf surfaces . A dirty-yellow maggot can usually be found in 
tiese mines . 

ommon stalk borers are now appearing in cornfields and can be expected to appear in many 
rops--oats, wheat, corn, tomatoes, and many flowers --during the next three weeks. Although 
tiey are still only 1/4-inch long, the distinctive coloration is noticeable. They have 
ellow-to-white stripes running lengthwise along the body. The middle section of the body 
5 purple, black, or brown; both ends are lighter colored. 

hese pests usually infest crops near fence rows, ditch banks, grass waterways, or any 
ther area where weeds were present for the moths to deposit eggs last August. These eggs 
re now hatching, and the worms are migrating to the nearest plants. 

ontrol is rarely recommended, since these worms usually remain on one plant and do not 
igrate throughout the field- -contrary to the impression held by some people. 

orn flea beetles are tiny, black, shiny beetles found on com leaves. They jump at the 
lightest disturbance, so approach the plants cautiously if you want to see them. The 
eetles strip tiny areas from the surface of the leaf. The tiny "scratches" are parallel 
o the leaf veins. Although not numerous enough to be damaging, these beetles transmit 
tewart's disease of corn, No control on field corn is practical for these insects unless 
hey are killing plants. 



Black cutworm damage reports , although not numerous , are more common this year than last 
Check low spots on fields. If plants are being cut above the growing point of the corn 
and if the worms are all over 1 inch long, the outbreak will be over very shortly, and the 
corn will continue to grow. However, you should treat immediately if the plants are being 
cut off below the growing point and many worms are less than an inch long. Direct the 
spray at the base of the plants ; use carbaryl (Sevin) at 2 or 3 pounds , diazinon at 2 
pounds, toxaphene at 3 pounds, or trichlorfon (Dylox) at 1 pound of actual chemical per 
acre in at least 20 gallons of water per acre; also, cover the spray by throwing soil at 
the base of the plants with a cultivator . 









Corn rootworm eggs will begin to hatch this week in the north half of Illinois. Poten- 
tially, fields of continuous corn in the northern half of Illinois may be affected. Many 
fields of second-year corn north and west of a line from Dixon to Peoria to Stronghurst 
may be damaged by the western corn rootworm . Other fields of second-year corn to the east 
and north of this line may also be damaged. The northern corn rootworm is most abundant 
north of Highway 36 (Pittsfield to Springfield to Decatur) , and is often a problem in fieL; 
where corn has been grown continuously for three or more years in the same field. 

I 
If you suspect or know that you have a resistant western or northern corn-rootworm prob- 
lem and if you did not use an organic phosphate or carbamate insecticide at planting time, 
apply one of these within the next two weeks. Use granules applied at the base of the con 
plants, and cover them by cultivation. A special applicator on the cultivator directs the 
phosphate granules at the base of the plant, and dirt is thrown over this deposit. 

Organic phosphate or carbamate insecticides are the only effective means of controlling 
resistant rootworms . The following materials have label approval for basal application 
and are recommended for control of resistant rootworms in Illinois. 

Rate per 

Insecticide acre (lb.) 

*BUXten I 

Diazinon 1 

Disulfoton (Disyston) 1 

Parathion (Niran) 1 

Phorate (Thimet) 1 

Carbaryl (Sevin) 2 






*Note : Effective June 1, 1969, BUXten 
granular has been granted USDA 
registration for use as a basal 
application for corn rootworm 
larval control in field corn. 
For best results, make the ap- 
plication before June 15 . 

In northern Illinois, the big question relates to rainfall and the effectiveness of plantin- 
time applications of rootworm insecticides. Did the 3- to 6-inch rains take the insecticid 
out of the rootworm zone? This is likely to vary with insecticides. Check the root systeir 
of plants this week and during the next two weeks for the infestations. If you find 5 or 
more worms per plant, use a basal application. 

Small worms are hard to find. Dig up the plant. Put the roots in a plastic bag. Examine 
the bag for tiny rootworms two times at 24-hour intervals. In another 10 days, the root- 
worms will probably be large enough to be seen in the field by shaking the roots over a 
piece of canvas or plastic. At this time, also tear open the roots; many rootworms are 
actually in them. 



Unfortunately, it may be too late to get through the corn with a cultivator by the time 
you find the rootworms . If you think the rain did seriously reduce the effectiveness of 
your planting-time treatment, information from our 1968 corn rootworm control demonstra- 
tions may help you decide on whether to make a basal application. 

First, 1968 was a year for optimum results from planting-time treatments. We had no 
tieavy rains between planting time and rootworm egg hatch. We applied diazinon to 1/2 
jf each plot as a basal application. Our results from 8 fields showed that a planting - 
time treatment plus a basal application yielded 1-1/2 percent more corn than the planting - 
time application alone. Under many conditions (including those of 1968), this gain 
rfould not justify the added expense. But with the heavy rains that came before rootworm 
3gg -hatch this year, making a basal application could produce much better results this 
/ear. If you feel certain your field will be heavily infested with rootworms, if you did 
lave heavy rains, the 1968 data may help you make a decision now, as you should recover 
at least the 1-1/2 percent in yield as in 1968 and most likely considerably more with 
this year's rainfall. 

Ihe potential for European corn-borer infestations is still uncertain. Corn-borer develop- 
nent this year parallels that of 1956, when we had one of our most-severe, first-generation 
infestations. Moth emergence is similar to that of 1956, egg-laying is a little later this 
/ear, and the corn about 5 to 10 inches shorter. Thus, borer survival may be slightly lower 
than in 1956. This year, we have also had more borers die in the pupal stage before they 
could emerge as moths. In southern Illinois, emergence is complete and egg-laying will soon 
De over. Examine the most-advanced fields now for possible treatment. Only a very small 
percentage of the fields are involved. 

[n south-central Illinois, emergence is almost done and about 5 to 20 percent of the moths 
ire yet to emerge. Egg -laying should be complete by June 20 to 25. On the east side of 
:he state, a few fields of the most-advanced corn will be involved. On the west side, 2 
;o 4 percent of the fields might have economic infestations. The next 7 to 10 days will 
letermine the importance of corn borer to the early corn. Continue to examine the most- 
idvanced fields carefully. 

vlthough the threat of economic damage from first-generation borers is not great in south 
md south-central Illinois, the survival rate may be high enough to cause damage later on. 

~.n central Illinois, about 10 to 30 percent of the moths are yet to emerge. Egg-laying has 
just begun, and it will continue for the next 2 weeks or a little longer. Much depends on 
he temperatures at night. If those temperatures remain high, the moths will deposit their 
;ggs quickly and egg-laying will be over. Cooler nights will mean that the egg-laying will 
:ontinue for a longer time, and about 5 to 10 percent of the fields will develop borer prob- 
.ems . Observe the most-advanced corn until the last few days of June. 

n north-central and northern Illinois, 20 to 45 percent of the moths are yet to emerge. 
ji occasional egg mass can be found. Egg-laying will continue into late June and early 
uly. Observe the most-advanced fields carefully, starting about June 20. 

o determine the need for treatment, measure the tassel ratio. Dig up a plant and measure 
rom the bottom of the plant to the tip of the longest leaf. Split the plant and find the 
eveloping tassel. Measure from the bottom of the plant to the tip of the tassel. Divide 
he tassel height by the plant height and multiply by 100. If the tassel ratio is 50 or 
jver and if 75 percent or more of the plants have corn-borer feeding on the whorl leaves, 
ihe field should be treated--but not until the tassel ratio is at least 35, preferably 40 
o 50. If there is corn-borer feeding in the whorl, the percent of plants required to 
ustify treatment can be reduced with higher tassel ratios. 



-4- 






Use 1 pound of actual diazinon in granular form per acre or 1-1/2 pounds of carbaryl (Sevi) 
as granules. For spraying, use the same amount of actual insecticide per acre, and direct 
the spray to the upper third of the plant. Aerial applications should be granules, not 
sprays or dusts. Allow 10 days between treatment and the ensiling of corn when applying 
diazinon; carbaryl has no waiting period. Commercial applicators may prefer to use para- 
thion, which provides good control of the corn borer. Parathion has a 12 -day waiting perid 
between treatment and harvest. 



SOYBEAN INSECTS 

Bean leaf beetles are now appearing and are eating holes in leaves . Do not treat unless 
the stands are being noticeably reduced. 

Alfalfa weevils and related alfalfa pests are feeding on the leaves of soybeans planted ir. 
fields where alfalfa was plowed down this spring. No controls are needed. 

FORAGE INSECTS 

Alfalfa weevil needs watching on second-growth alfalfa in central and north-central Illi- 
nois; also, on the east side of the state to as far north as Kankakee and LaSalle. On the 
west side of the state, this problem tapers off to the south. If second-crop alfalfa is 
not growing and is browning and if worms are present, apply one of the weevil insecticides 

STORED-GRAIN INSECTS 

Stored-grain in sects are lying in wait for wheat harvest, which is just around the corner 
in southern sections . To protect wheat from insect damage, follow these steps: 

1. Sweep up and clean out all old grain, chaff, and other debris inside and around the 
storage bin. 

2. Apply a water -base spray of 1.5-percent premium-grade malathion (mix 5 ounces of 50- 
to 75-percent malathion emulsion concentrate per gallon of water) or a 2.5-percent 
methoxychlor (mix 14 ounces of 25-percent methoxychlor -emulsion concentrate per gallon 
of water) to the ceiling, walls, and floor of the bin. 

3. If the wheat is to be stored for a month or longer, treat it with a premium-grade 
malathion dust (40 to 60 pounds of 1-percent dust per 1,000 bushels), or spray (1 pint 
of 50- to 57-percent emulsion concentrate in 5 to 5 gallons of water per 1,000 bushels 
The dust is best applied on the surface of the wheat in the combine hopper; the spray, 
as the wheat is augered or elevated into the bin. 

4. Clean out the combine, auger, and other grain-handling equipment. An easy way to cleaj 
the combine is to discard or feed to livestock the first 2 or 5 bushels that pass 
through . 

HOMEOWNER INSECT PROBLEMS 

Sod webworm moths can be observed around shrubbery, also on window screens and around ligh'i 
at night. They are laying eggs for the first -generation larvae, which will be feeding dur 
ing late June. This generation usually does not do economic damage, as docs the second 
generation in late July and August. But lawns should be watched for damage anyway. If 
control is necessary, use carbaryl (Sevin) or diazinon- -either as spray or granules. 






Galls of all shapes and descriptions are appearing on the leaves of maple, oak, and 
several other shade trees . These galls are caused by mites , wasps , grubs , aphids , and 
other insects. Each one has its own special tree species and gall formation. In general, 
the small insect begins to feed on the leaf in its early development, sometimes almost in 
the bud stage. As a means of protection, the leaf develops this corky growth around the 
insect. This growth may disfigure the leaf, but it rarely, if ever, hurts the tree. It 
is too late to do anything now. A spray of malathion in the early stage next spring would 
reduce the galls next year. 

Seventeen -year locusts are being reported in northeastern Illinois. These pests appear 
every 17 years --as the navy and black, clear-winged adult. Their high-pitched shrill 
singing can be heard for some distance. They deposit their eggs on the tips of twigs. 
The young hatch, go into the ground, and will emerge as adults 17 years from now. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS. 



WEEDS 



So far, preplant applications of Sutan-atrazine and Ramrod- at razine have performed well 
in corn. Some grasses emerged in fields where Sutan-atrazine or straight Sutan was used, 
but then twisted, curled, and died. More farmers used the Ramrod-atrazine combination this 
year and got good results. This is one of the outstanding corn treatments. 

Many fields received quackgrass treatments too late. If you have some perennial grasses 
(quackgrass or wirestem muhly) in corn, do the best you can with cultivation and plan to 
make a good atrazine treatment this fall. Atrazine is effective, but the treatments 
should be made in the fall or spring before plowing --not after seedbed preparation. 

If you have equipment for direct spraying and there is enough height difference between 
annual grass weeds (foxtail, panicum) and corn, you might try Lorox or Dowpon as directed 
sprays. However, it is better to rely on cultivation before the grass gets too high, be- 
cause these treatments may injure the crop. 

POSTEMERGENCE HERBICIDES FOR CORN 

Do not mix 2,4-D with atrazine and oil. If corn has been recently sprayed with 2,4-D, 
there may even be some risk in using atrazine and oil soon after. Although no one has reported 
any corn injury from 2,4-D, be sure to apply proper rates. Do not make applications if the 
corn is under stress. 

2,4-D spraying is economical, effective, and especially helpful where no herbicide has been 
used or where only a grass killer such as Sutan, Ramrod, or Lasso was used. 2,4-D will con- 
trol velvetleaf if applied before the weeds are big enough to effectively compete with the 
crop. 

AAtrex, applied preemergence or postemergence, will generally control smartweed. If you 
still have a smartweed problem, 2,4-D postemergence may curl the leaves but probably will 
not give good control. AAtrex action is sometimes delayed on velvetleaf. The velvetleaf 
may emerge but then dies . 

Banvel postemergence gives good smartweed control, but watch out if soybean fields are 
; near cornfields that you are treating. The risk of injuring soybeans is high. 



POSTEMERGENCE HERBICIDES FOR SOYBEANS 

Tenoran (chloroxuron) is used mainly to control broadleaved weeds where a preemergence 
herbicide such as Treflan has been used. It gives fairly good control of pigweed, lambs- 
quarter, smartweed, jimsonweed, morning glory, and cocklebur. 

Apply the herbicide when broadleaved weeds are less than 2 inches high and when grass weed 
are less than a half inch high. Treat velvetleaf before it is an inch high, because contrl 
is difficult after that. Tenoran works better on cocklebur after two true leaves emerge, 
rather than earlier when the "leathery" cotyledons are exposed. 

To broadcast Tenoran, use 2 to 3 pounds of the 50 -percent wettable powder per acre with 1 
pint of Adjuvan T surfactant added per 25 gallons of spray solution. The rate for banding 
is proportionately less. Soybeans treated with Tenoran usually show leaf burn, but the 
injury may not affect yields. 

2,4-D may be broadcast from 10 days before soybeans begin to bloom until mid-bloom, or it 
can be used as a postemergence directed spray when soybeans are 8 to 10 inches tall and 
cockleburs are 3 inches tall. It gives fairly good control of annual morning glory and 
giant ragweed, too. 

After being sprayed with 2,4-D, soybeans may show early wilting, curving or cracking of th 
stems, and proliferate growth at the base of the plant. If you use too much or apply the 
chemical under unfavorable conditions, lodging may increase and yields may decrease. 

Postemergence herbicides on soybeans have not gained much acceptance in Illinois. 



SPECIAL ANNOUNCEMENTS 



June 


17, 


June 


17, 


June 


18, 


*June 


18, 


*June 


19, 


June 


19, 


June 


23, 


June 


23, 


June 


24, 


June 


24, 



■X0T1;' 



Office of the Brown County Extension Adviser, Robert Hayward, Mt. Sterling 
Office of the Henderson County Extension Adviser, Curt Eisenmayer, Stronghurst 
Office of the Knox County Extension Adviser, Don Teel, Galesburg 
Office of the Livingston County Extension Adviser, Paul T. Wilson, Pontiac 
Office of the McLean County Extension Adviser, Gene Mosbacher, Bloomington 
Office of the Iroquois County Extension Adviser, Ken Imig, Watseka 
Office of the Whiteside County Extension Adviser, Fred Tincher, Morrison 
Office of the LaSalle County Extension Adviser, Jim Daugherty, Ottawa 
Office of the JoDaviess County Extension Adviser, Geo. Swallow, Elizabeth 
Office of the Winnebago County Extension Adviser, Dick Kerr, Rockford 

THE DATES OF THE LIVINGSTON AND MCLEAN COUNTY MEETINGS HAVE BEEN CHANGED FROM 
PREVIOUS ANNOUNCEMENTS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen Sturgeon, Uni- 
versity of Illinois College of Agriculture , Urbana-Champaign and Illinois Natural History 
Survey . 

WEEDS: E.L. Knake, Department of Agronomy . 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 



J-,V- I 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




INSECT. WEED & PLANT DISEASE SURVEY BULLETIN 



ITATE/COUNTY/LOCAL GROUPS/US DEPABTMEMT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 13, June 17, 1969 



This series of weekly bulletins -provides a general look at the insect , weed, and plant 
disease situation (fruit and commercial vegetables excepted) > along with suggested, 
abbreviated control measures. Each individual should check his own fields to deter- 
mine local conditions. 



INSECTS 



CORN INSECTS 

European corn borer egg-hatch in south-central Illinois below Route 16 reached its peak 
with most of the corn too small for borers to survive. The majority of the corn there 
is less than 40 inches tall, with about 20 percent over 40 inches and a tassel ratio of 
15 or less in these taller fields. Late -planted fields in this area should be watched 
carefully later on for second-generation borers. 

In central Illinois up to Route 9, moth -emergence is all but complete. Egg-laying is in 
full swing with hatch just beginning. Very little whorl feeding is evident. Less than 
10 percent of the fields have corn taller than 40 inches. Moths are beginning to con- 
centrate on the earlier fields. The decision on whether treatment is needed in these 
early fields can be made early next week. 

Between Routes 9 and 6, egg-laying has just begun, with 10 to 25 percent of the moths 
yet to emerge. By late next week, egg -hatch will be occurring in the earliest fields, 
and a decision can be made then about treatment. 

torth of Route 6, about 30 percent of the moths have yet to emerge and egg- laying is 
starting. Most of the corn is about 10 inches tall. In a few fields, it is close to 
30 inches high. Watch these early planted fields during the first week in July for 
whorl feeding, and treat if necessary. 

In all areas of the state where the com borer is a potential problem, cool nights have 
temporarily delayed egg- laying; also, moth -emergence. This delay can allow corn to reach 
an optimum height for borer survival. 

To determine the need for treatment, measure the tassel ratio. Dig up a plant and mea- 
sure from the bottom of the plant to the tip of the longest leaf. Split the plant and 
find the developing tassel. Measure from the bottom of the plant to the tip of the 
tassel. Divide the tassel height by the plant height and multiply by 100. If the tas- 
sel ratio is 30 or over and if 75 percent or more of the plants have corn-borer feeding 
on the whorl leaves, the field should be treated- -but not until the tassel ratio is at 
least 35, preferably 40 to 50. If there is corn-borer feeding in the whorl, the per- 
cent of plants required to justify treatment can be reduced with higher tassel ratios. 



-2- 

Use 1 pound of actual diazinon in granular form per acre or 1-1/2 pounds of carbaryl 
(Sevin) as granules. For spraying, use the same amount of actual insecticide per acre, 
and direct the spray to the upper third of the plant. Aerial applications should be 
granules, not sprays or dusts. Allow 10 days between treatment and the ensiling of corn 
when applying diazinon; carbaryl has no waiting period. Commercial applicators may pre- 
fer to use parathion at 1/2 pound actual per acre, which will provide good control of 
the com borer. Parathion has a 12 -day waiting period between treatment and harvest. 

Corn rootworm eggs will be hatching soon. If you know or suspect that you have a root- 
worm problem and did not use an organic phosphate or carbamate insecticide at planting 
time, apply one of the recommended chemicals now as a basal treatment. Do not wait to 
count larvae. In many fields --especially early planted ones --the corn will be too tall 
for a basal treatment by the time rootworms are large enough to be found and counted. 

Insecticides suggested for basal treatment are diazinon, phorate (Thimet) , BUXten, di- 
sulfoton (DiSyston) , or parathion (Niran)--at the rate of 1 pound of actual chemical 
per acre, and carbaryl (Sevin) a t the rate of 2 pounds actual per acre. 

Black cutworm damage is still being reported in various locations in Illinois. Check 
cornfields For areas of missing plants, especially in the low spots. If plants are 
being cut above the growing point of the corn and if the worms are all over 1 inch long, 
the outbreak will be over very shortly, and the corn will continue to grow. However, 
you should treat immediately if the plants are being cut off below the growing point 
and many worms are less than an inch long. Direct the spray at the base of the plants; 
use carbaryl (Sevin) at 2 or 3 pounds, diazinon at 2 pounds, toxaphene at 3 pounds, or 
trichlorfon (Dylox) at 1 pound of actual chemical per acre in at least 20 gallons of 
water per acre; also, cover the spray by throwing soil at the base of the plants with 
a cultivator. 

Billbugs damage to young com stands has been observed. They are snout beetles that 
drill holes in stalks below ground level. When the leaves emerge, they have a series 
of holes in them. The feeding of a single beetle may kill a small plant, while a 
larger plant may continue to grow normally with only a few rows of holes across the 
leaves. Suckering and distorted growth are other symptoms of billbug injury. 

White grub damage has been reported in both corn and soybeans. These grubs have hatched 
in 1968 or 1967 from eggs laid by June beetles. Half -grown grubs will continue to feed 
all summer. Full-grown grubs will soon pupate and quit feeding. There is no effective 
chemical control for grubs in a soybean field after the plants are up. In a cornfield, 
some control can be obtained with 1 pound actual of aldrin or heptachlor, applied as a 
spray to the base of the plant and cultivated-in immediately. Do not use aldrin or 
heptachlor on a soybean field . 

Common stalk borers are moving out of grasses and weeds into border rows of corn. These 
whitish-brown, striped worms with a purple band around their middle feed in the whorl of 
the corn plant. Emerging leaves have irregular holes in them. Plants may be killed or 
severely damaged by this pest. Chemical control is difficult to achieve because the 
borers are usually too deep in the whorl of the plant for insecticides to reach them. 

FORAGE INSECTS 

Alfalfa weevil activity is about over . Continue to watch for damage to the new growth 
of second-crop alfalfa north of a line from Jacksonville to Watseka. If the field does 
not green-up soon after the first cutting, treat it promptly. Larvae are present in 
fields in this area, but pupation and adult emergence is progressing rapidly. 



HOMEOWNER INSECT PROBLEMS 

Elm leaf beetles have begun to hatch, especially Chinese, this week. The small, dirty- 
yellow to black larvae feed on the underside of leaves- -skeltonizing them and leaving 
only the veins. Sprays of carbaryl (Sevin) or malathion now will reduce the damage. 
An additional spray 10 to 12 days later will help control this insect. 

Bagworms have hatched and have begun to feed in the central part of the state. Spray 
with either malathion, carbaryl (Sevin), or diazinon. Follow label directions. 

Aphids of many species are commonly found on lots of trees --especially willow, tulip, 
and sycamore; also on shrubs, including roses. In most instances, these aphids, or 
plant lice, do very little damage. If damage is serious with leaves curling and drying, 
apply malathion as a spray, using 2 teaspoons of 50- to 57-percent liquid concentrate 
per gallon of spray. 

Bean leaf beetles are chewing holes in green bean leaves. Carbaryl (Sevin) applied as 
a dust or spray will effectively control this insect. Also, the same chemical as a 
dust or spray will control both the spotted and striped cucumber beetle . These two 
beetles, particularly the black and yellow striped adults, feed on young plants of cu- 
cumbers, melons, and other vine crops. Many times, they cause these young plants to 
wilt and die, due to bacterial wilt- -a disease carried by the beetles. 

Some homeowners who have applied chlordane as a foundation spray may wish to repeat 
this practice during the next few weeks to provide protection against house- invading 
insects such as crickets, water bugs, ants, spiders, and millipedes. One pint of 45- 
percent chlordane liquid concentrate added to 3 gallons of water is usually sufficient 
to treat the foundation of the average-size home. Be sure to spray to the point of 
runoff; also, treat cracks around steps and sidewalks along the foundation. 



WEEDS 



Several Illinois vine weeds may cause problems. Hedge bindweed got a good start in 
some cornfields, but 2,4-D will control it. Field bindweed is much more difficult 
to control. 

Control wild sweet potato with 2,4-D, but be sure to apply it at the right time. Use 
the usual rate of 2,4-D in corn when the sweet potatoes are in the bud stage- -just 
before the buds open up into flowers. At this stage, 2,4-D moves with food reserves 
from the leaves downward to the tubers and gives greater control. The bud stage may 
be late enough to require high-clearance spray equipment. 

Wild cucumber control has been relatively good where AAtrex was applied preemergence . 
AAtrex gave the best control when it was incorporated. 2,4-D applied after the weeds 
emerge will not help much. 2,4,5-T controls wild cucumber much better than 2,4-D, and 
can be used in fence rows and non-crop areas. However, 2,4,5-T does not have federal 
clearance for use in corn. 

You can control annual morning glories in corn with a preemergence herbicide such as 
AAtrex, but some of the soybean herbicides like Amiben and Lorox do not give good 
morning glory control. In corn, 2,4-D postemergence controls annual morning glory. 
In soybeans,' a postemergence application of 2,4-DB may give fair control where the prob- 
lem is severe. Before using 2,4-DB on soybeans, however, consider the injury risk. 
If you use 2,4-DB, make careful and accurate applications. 



-4- 

Cocklebur , though not a vine, is in a similar category as annual morning glory. It is 
easy to control in corn with 2,4-D. In soybeans, Amiben gives erratic cocklebur control. 
2,4-DB gives fairly good control of cocklebur in soybeans, but use it only for the more 
serious problems, and consider the risks of soybean injury. 

VI AGRONOMY DAY FEATURES RESEARCH, MANAGEMENT 

Illinois farmers, caught in the middle of a cost-price squeeze, must look for new ways to 
lower costs and raise profits. University of Illinois agronomists are not promising to 
unveil any magical solutions to the problems at Agronomy Day this year, but most of the 
stations on the tour present information geared to help farmers get the most from limited 
cash outlays. At each of the 16 research plots, specialists will explain the work they 
are doing. 

Agronomy Day Chairman Gene Oldham says that the first tour starts at 7 a.m. on June 26. 
Tours will start every 10 minutes thereafter until 1 p.m. The tours last about 2-1/2 
hours. So if you come early, you can make the full tour and be on your way home by 
10 a.m. Lunch will be available on the grounds at the Agronomy South Farm in Urbana. 

Here are the stops on the Agronomy Day tour: 

1. Water Pollution. 

2. What Is New in Chemical Weed Control? 

3. Soil Organic Matter and Herbicides. 

4. Corn for Specific Purposes. 

5. Micronutrient Survey. 

6. Alfalfa Varieties. 

7. Alfalfa Seeding. 

8. Plant Diseases. 

9. Tillage. 

10. Nitrogen- -What Is It and How Much. 

11. Soybean Fertility. 

12. Oat Production. 

13. Wheat Production. 

14. Insect Report. 

15. Corn Fertility. 

16. Soybean Production. 

READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS . 

SPECIAL ANNOUNCEMENTS" 

Pesticide Dealers and Applicators Field Days/1: 30 p.m. each day: 

June 23, Office of the Whiteside County Extension Adviser, Fred Tincher, Morrison 

June 23, Office of the LaSalle County Extension Adviser, Jim Daugherty, Ottawa 

June 24, Office of the JoDaviess County Extension Adviser, George Swallow, Elizabeth 

June 24, Office of the Winnebago County Extension Adviser, Dick Kerr, Rockford 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty 3 Steve Moore, Kosaoe Randell, Don Kuhlman, and Stephen Sturgeon, 

University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural 

History Survey. 

WEEDS: E.L. Knake, Department of Agronomy. 

AG COMMUNICATIONS : Del Ddhl. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



%/tvf 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT, WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US DEPARTMEMT OF AGRICULTURE COOPERATING 



i i oft! 






r- - 



)R IMMEDIATE RELEASE 



No. 14, June 27, 1969 

lis series of weekly bulletins provides a genera Trvdhli at the insect, weed, and plant 
Isease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
"eviated control measures. Each individual should check his own fields to determine 
jcal conditions. ,, . i L .•,;.,■,.•• 



INSECTS 



JRN INSECTS 



le first generation of European corn borers has almost been eliminated as a general threat 
d early corn this year. 

lthough first -generation borers may not present a general problem, some fields that 
3re planted early will be damaged. This is particularly true in the area bounded by the 
llinois River on the east, Route 136 on the south, and Route 6 on the north. The rain 
id wind storms of the past week apparently whipped egg masses off leaves and killed a 
reat many moths, because it is now difficult to find either moths or eggs in early corn, 
f we have misjudged the effect of these storms, egg laying will begin with the first 
ight that is warm and quiet. Such nights enable moths to fly and deposit eggs without 
3ing disturbed. 

s an insurance, continue to examine early planted fields in western and northern Illinois 
or signs of whorl feeding for another week. It will pay to treat fields with an insecti- 
ide if tassel ratios are over 30 and if 75 percent of the plants show whorl feeding, but 
o not apply insecticide until the tassel ratio is at least 35, preferably 40 to 50. Higher 
assel ratios require a lower percent of plants with whorl feeding to warrant insecticide 
ontrol. Naturally, the earliest fields will now have the highest tassel ratios. 

d determine the tassel ratio, dig up a plant and measure from the bottom of the plant to 
tie tip of the longest leaf. Split the plant and find the developing tassel. Measure from 
tie bottom of the plant to the tip of the tassel. Divide the tassel height by the plant 
eight and multiply by 100 . 

org rootworm larvae have not yet been reported, but they should appear this week. If you 
now or suspect that you have a rootworm problem and did not use an organic phosphate or 
arbamate insecticide at planting time, apply one of the recommended chemicals now as a 
asal treatment. Do not wait to count the larvae. In many fields- -especially early planted 
nes--the corn will be too tall for a basal treatment by the time rootworms are large enough 
o be found and counted. 

he insecticides suggested for basal treatment are diazinon, phorate (Thimet) , BUXten, disul- 
oton (DiSyston) , or parathion (Niran)--at the rate of 1 pound of actual chemical per acre; 
nd carbaryl (Sevin) , at the rate of 2 pounds actual per acre. 



-2- 

Common stalk borers are migrating from the hollow-stemmed grasses and weeds in fence rows 
to other crops. Corn plants along the edges of fields are being killed or severely chewed 
This striped worm with a brown, purple, or black area around the middle of the body can 
easily be found in dead or dying weed stems, or in the corn plants. 

We have been asked to make control suggestions, ones to be used only if you insist on tryi;; 
to control these borers. First, mow the fence row- -a stubble beater would be best. This' 
will kill some worms, but will drive the worms out of the weeds and grasses in the fence 
row and into the corn. Therefore, spray the stubble, soil, and first two or three rows o 
corn immediately- -before the worms get into the corn. Use 2 pounds of 80-percent carbaryl 
(Sevin) in 20 gallons of spray per acre. This suggestion is only for a trial. 

Garden centipedes (symphylans) are now appearing. Damage may occur to all plants in an 
area within a field, or only individual plants may be affected. The most-common symptoms 
are severe plant stunting and purpling, or the plants may die. Root systems are weakened 
or are nonexistent. Numerous, small, grey -to -white, many legged creatures can be found in 
the soil around the plants. They disappear very rapidly. If you have this condition, make 
plans to control them in these areas next year. 

Several different kinds of aphids have been found frequently on corn. None of these are 
the corn leaf aphid, and none are numerous enough to cause injury. It is too soon to make 
predictions about the prospects for corn leaf aphids . 

SOYBEAN INSECTS 

Corn-seed maggots have been reported doing damage to stands of soybeans . The maggots 
attack the seeds during germination, and will also tunnel into the stems afterward. Ohio 
extension entomologists report the same problem in some areas of that state. If you re- 
plant, you can use diazinon as a planting-time treatment. However, it is not likely that 
damage from these maggots would occur with rapid germination; therefore, insecticide might 
not be needed now. 

LIVESTOCK INSECTS 

The number of flies on cattle now on pasture is building up, particularly in the central 
and southern sections of Illinois. Fly counts on untreated herds this week showed the 
following averages: 

Average number flies per animal 
Section of Illinois Face flies Horn flies Stable flies 

Southern 5 

Central 10 

Northern 2 

An average of one horse fly or deer fly per animal was also found on cattle in the southerr 
section. The number of flies will increase sharply with warm weather, particularly in the 
northern section. The wet condition we now have favors the development of flies. Studies 
have shown that the pasture fly complex will cause a 10- to 20-percent loss in milk or beef 
production during a normal fly season. 

For control on dairy cattle, apply Ciodrin as a 2-percent oil or water-base spray- -at 1 to 
2 ounces per animal and 2 to 4 times per week. A 1-percent dichlorvos (DDVP) or a 0.1- 
percent pyre thrum spray applied at 1 to 2 ounces per animal each day can also be used. 



350 


5 


100 


6 


10 


1 



Pay particular attention to the animal's legs and undersides when spraying. For dry stock 
and young stock on pasture, use a 1-percent Ciodrin, water-diluted spray. Apply 1 to 2 
pints per animal, as often as once per week if needed. Ciodrin is the most-effective 
insecticide for face-fly control. All of the above insecticides provide good control of 
horn flies and fair control of stable flies. 

For control on beef cattle, apply a water-base spray of 0.5-percent toxaphene, using 1 to 
2 quarts per animal every three weeks. Toxaphene provides excellent control of horn flies, 
fair control of stable flies, and poor control of face flies. 

If face flies become serious, use Ciodrin as suggested for dairy cattle. A canvas or 
burlap head-oiler or back-oiler, saturated with 5-percent toxaphene in oil, will provide 
some relief against face flies. Do not apply toxaphene to beef cattle within 28 days of 
slaughter. 

HOMEOWNER INSECT PROBLEMS 

Mimosa webworm larvae can be found feeding on honey locust and mimosa in the southern 
sections of the state. Within the next week or two, they should become apparent in the 
central and northern sections. They are small, gray -to -brown, striped, active cater- 
pillars that use a silken thread to tie a bunch of leaflets together. They skeletonize 
these leaflets and then form a new nest. The old nest turns brown, and the leaflets 
die. Several generations will follow this first one. Treatments made now in the southern 
sections and during the next week or two in the central section will help prevent more- 
severe damage by this insect later in the summer. However, an additional treatment in 
late July and August may still be needed. 

\ spray of either carbaryl (Sevin) using 2 pounds of 50 -percent wettable powder per 100 
gallons of water or malathion using 1 quart of the 50- to 5 7 -percent liquid concentrate 
per 100 gallons of water is effective. 

First-generation elm leaf beetles are skeletonizing the leaves of Chinese and other elms 
in the central and northern sections. The damage by first -generation worms is about over 
in the southern part of the state. These small, dirty-yellow to black worms feed on the 
undersides of leaves and congregate in large numbers next to the trunk at ground level 
vhen they are ready to pupate. A spray of carbaryl (Sevin) or malathion is effective. 
Spray treatment may be needed again in late July in southern sections to control second- 
generation worms . 

•latching and feeding by cottony maple scale is beginning on the leaves of soft maple and 
3ther trees and shrubs. A sign of infestation is the appearance of white cottony masses 
(like popcorn) on small twigs and branches . The female scale has laid hundreds of eggs in 
-hese cottony masses. Apply control measures within the next week or two. The young 
scales must be killed before they develop a protective covering. A malathion spray is 
effective . 

Bagworm hatch is now complete in northern sections, and the larvae are feeding on ever- 
greens and other trees and shrubs. Sprays should be applied immediately for best results. 
Jse carbaryl, malathion, or diazinon. Follow the directions on the label. In central 
uid southern sections, it is still not too late to spray shrubs for protection against 
pagworms. 



-4- 

WEEDS 

Several Illinois vine weeds may start to cause problems about now. Hedge bindweed got a 
good start in some cornfields, but it is rather easily controlled with 2,4-D. Field 
bindweed is much more difficult to control. 

Wild sweet potato can be controlled with 2,4-D, but the timing of the application is 
critical. Use the usual rate of 2,4-D in corn when the sweet potatoes are in the bud 
stage- -lust before the buds open up into flowers. At that stage, 2,4-D moving toward 
the tubers with food reserves from the leaves gives the most -complete control. The bud 
stage may be late enough that high clearance equipment will be needed. 

Wild cucumber control has been relatively good where AAtrex has been applied preemergence, 
preferably incorporated. As a postemergence treatment, 2,4-D isn't much help. 2,4,5-T 
controls wild cucumber much better than 2,4-D. 2,4,5-T can be used in fence rows and in 
noncrop areas, but it does not have federal clearance for use in corn. 

.A nnual morning glories are often controlled in corn with a preemergence herbicide such 
as AAtrex. Some soybean herbicides like Arniben and Lorox do not give good morning glory 
control. In corn, 2,4-D postemergence gives good control. In soybeans, postemergence 
application of 2,4-DB may give fair control where the problem is severe. But before 
using 2,4-DB on soybeans, consider the risk of injury. If you use 2,4-DB, make careful 
and accurate applications . 

Cocklebur , although not a vine, is similar to annual morning glory. It is easy to control 
with 2,4-D in corn. In soybeans, cocklebur control is somewhat erratic with Arniben. 
2,4-DB can give fairly good cocklebur control in soybeans, but go easy. Use 2,4-DB for 
only the most-serious problems, and consider the risks before you use it. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS, 



SPECIAL ANNOUNCEMENTS 



Garden Centipede (Symphylan) Research Plot Demonstrational Meeting 

July 9. . .Thomas Watson Farm (Rock Island County). . .9 a.m. 

Go 4-1/2 miles east of the Mississippi River or 4-1/2 miles west of Illinois Cit? 
on Route 92, then south on the blacktop (County Road B) for 1-1/2 miles and east 
for 1/4 mile. 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen Sturgeon, Uni- 
versity of Illinois College of Agriculture , Urbana-Champaign and Illinois Natural History 
Survey . 

WEEDS: E.L. Knake, Department of Agronomy 

AG COMMUNICATIONS: Del Dahl. 

The information for this report was gathered by these people, staff members , county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT, WEED & PLANT DISEASE SURVEY BULLETIN 

ATE/COUNTY/LOCAL GROUPS/U S. DEPARTMEMT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 15, July 3, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures. Each individual should check his own fields to determine 
local conditions . , ~,„, T . 



INSECTS 



CORN INSECTS 



C \ 1 
USRAftX 



European corn borer moths were apparently killed by rain storms about as fast as they 
emerged from the pupal cases during the past 2 weeks. However, some did escape, de- 
posited eggs, and these borers did survive. Decisions about treatment should be made 
now. 

In southern and south-central Illinois, egg-laying is over and some of the most- 
advanced fields have up to 30 percent of the plants infested with 2 to 3 half-grown 
borers per plant, but this is not enough to warrant use of an insecticide. The borers 
were still behind the leaf sheaths, and had not yet bored into the stalks. This many 
first -generation borers, although not plentiful enough to warrant control, will supply 
plenty of moths to produce lots of second-generation borers. 

In central Illinois, there are a few borers in corn on the east side of the state, but 
not enough to warrant control. An occasional field of the most-advanced corn on the 
west side of the state may warrant treatment. A few egg masses can still be found in 
these fields; survival of borers hatching from these eggs will be high. 

In northern Illinois, only a very few fields have enough corn borers to warrant chemi- 
cal control. Moths and eggs are scarce. 

Fields with tassel ratios approaching 50 and having 40 percent or more whorl feeding 
with an occasional egg mass still to hatch warrant use of an insecticide. Use diazinon 
or carbaryl (Sevin) granules . 

Corn rootworms were found hatching all the way to the northern boundary of Illinois 
this week. Have excessive rains killed newly-hatched worms? Small rootworms will 
likely be killed, where water stands in ponds. Newly hatched rootworms will probably 
drown in those fields where the soil is saturated and water stands between the rows 
for a day or two. Since the hatch of worms extends over a 3-week period, these rains 
may help reduce rootworm populations, but the rains are not likely to completely con- 
trol rootworms. 

Rains may have decreased the effectiveness of insecticides applied at planting time. 
Examine the roots right away. If you find 5 or more rootworms per plant, it will pay 



to make a basal application of an insecticide immediately, using the cultivator to 
cover the insecticide. Within a week, it will be too late. Use BUXten, carbaryl 
(Sevin) , diazinon, disulfoton (Di-Syston), parathion (Niran) , or phorate (Thimet) . 
Direct these at the base of the plant and cover with dirt. 

Corn blotch leaf miners are still being reported. They are extremely numerous in some 
fields this year. Whether or not they are of economic importance is questionable, but 
they are often confused with other problems. The adult, which is a fly, makes tiny 
elongated punctures in groups about 1/16 of an inch long- -usually in the tip of the 
leaf. The maggot mines between the upper and lower leaf surfaces. A dirty-yellow mag- 
got can usually be found in these mines . 

.An insect with the scientific name Smyra henrici is now present in cornfields. This 
caterpillar and others strip the chlorophyll from the lower leaves of the corn. Later, 
they devour the entire leaf. Although not of importance, the damage is often erroneous 1) 
thought to be caused by corn borer. 

Corn flea beetles can still be found in cornfields. They will gradually become more 
abundant late in July and August. 

Corn leaf aphids were found in Pulaski and Alexander counties on sorghum this past week, 
and in central Illinois this week. None have appeared on corn as yet, but several other 
aphids (English grain aphid and potato aphid) have been collected from corn. Fortunatel} 
the corn leaf aphids in Pulaski and Alexander counties were heavily parasitized by a 
small wasp. No control measures are recommended for this week. 

Thrips are very common in whorls of corn. No economic damage has been observed. 

SOYBEAN INSECTS 

Bean leaf beetles have been feeding in soybeans , but damage is not severe . They eat 
holes in the leaves. This green to red beetle is hard to find; they drop to the ground 
at the slightest disturbance. No control is needed now. 

Small grasshoppers can be found in hay-crop fields, in fence rows, and in some cases 
they are feeding on the leaves of soybeans in the edge of rows. No controls are recom- 
mended now. 

Southern corn rootworm adults (also known as the spotted cucumber beetle) are present 
in soybean fields. They eat the surface of the leaves. They are not of enough im- 
portance to warrant control. 

LIVESTOCK INSECTS 

Barn flies are bothersome particularly in central and southern sections, and populations 
are expected to increase sharply with the warmer weather. The house fly and the blood- 
taking stable fly (needle-like beak) make up the barn fly complex. Both flies spend 
90 percent of their time sitting on barn walls, support posts, fences, etc., and only 
about 10 percent of their time on the animals. Therefore, there is no need to spray 
cattle kept on dry lot. Begin controls now before the flies become too numerous. The 
following program will provide good results: 

1. Practice good sanitation. Eliminate fly-breeding materials- -such as manure, rotting 
straw, wet hay and feed- -as often as possible. Spreading this refuse where it can 
dry makes it unsatisfactory for fly development. 



-3- 



Apply a barn spray to the point of run-off to the ceilings and walls of all live- 
stock buildings. Also spot-spray outside around windows and doors and along 
fences in the lot. The following insecticides are suggested for this purpose: 



Insecticide 



Amount 
per 100 
gallons 
of water 



Diazinon, 50-percent wettable powder 

Dimethoate, 23-percent (Cygon) liquid 
concentrate 

Rabon, 25-percent liquid concentrate 

Ronnel , 24-percent (Korlan) liquid 
concentrate 



16 pounds 



Length of 
control 



2 to 4 weeks 



4 gallons 4 to 6 weeks 
4 gallons 4 to 6 weeks 

4 gallons 1 to 5 weeks 



Use only ronnel in poultry houses. All materials are cleared for use in dairy, 
beef, swine, sheep, and horse barns. Always caution farmers to cover feed and 
water troughs before spraying. Do not spray animals with these materials at the 
dosages suggested. Remove animals before spraying the barns. Do not spray the 
milk storage room. 

Supplement good sanitation and barn sprays with a spray bait material. Use 2 to 
4 ounces of dichlorvos (DDVP) or naled (Dibrom) in a mixture of 1 gallon of clear 
corn syrup and 1/2 gallon of warm water. Apply this from a small tank sprayer to 
the favorite fly roosting areas. 

Barn foggers using insecticides like dichlorvos (DDVP), pyrethrum, or naled 
(Dibrom) give a quick kill of flies during the fogging operation (10 to 20 minutes) , 
but the effect is not lasting. When fly populations become intense, even twice a 
day fogging fails to provide satisfactory fly control for the farm- -even though the 
barn is kept temporarily free of flies. .As normally used, fogging does not leave 
enough insecticide deposit on the animals to protect the cattle from flies when on 
pasture. Coarse sprays applied to the animals are best for this purpose. 



WEEDS 



As soon as you're through cultivating, catch your breath, then sharpen the hoe and go 
after the volunteer corn in soybeans while it's still small enough to chop off with 
one whack. When soybeans quit growing, you may see velvetleaf or jimson weed popping 
above the beans. If you only have 37 such weeds in a 40-acre bean field, a sharp hoe 
is usually the most -practical and easiest means of control. 

Don't forget good fencerow weed control . Two miles of fencerow 4 feet wide is about 
an acre. Five pounds of Dowpon plus a quart of 2,4-D (1 pound active) in 50 gallons 
of water, applied as a coarse spray, can control both broadleaved and grass weeds in 
a two-mile stretch. This combination makes an easy and inexpensive control program. 
You can kill poison ivy in fencerows with amitrole or amitrole-T. 



-4- 



DE LAY -SCHEDULE INFORMATION 



After applying some herbicides on corn, you'll have to wait awhile before the crop 
can be cut for silage. Here's a rundown: 

AAtrex --OK for silage corn. AAtrex can also be used for grain and forage sorghum and 
sorghum-sudan hybrids. Do not graze treated areas or feed treated forage to livestock 
for 21 days after application. 

Ramrod - -OK for silage corn. Do not graze or feed sorghum (milo) forage or silage from 
treated fields to dairy animals. 

Ramrod/atrazine mixture - -same as for Ramrod. 

Lasso - -Wait 12 weeks after treatment before harvesting immature corn forage or feeding 
it to cattle. 

Randox-T --OK for silage corn. (Silage com not listed on Randox label.) 

Sutan --OK for silage corn. 

Knoxweed --OK for silage corn. 

Londax - -Restriction for nonuse on silage corn has apparently been lifted. 

There are inconsistencies between labels that may be difficult to interpret. Some 
labels specifically state the corn types on which a herbicide may be used- -such as 
hybrid seed corn, field corn, sweet corn, silage corn, and popcorn. Other labels 
are vague, and may simply say that "corn" or "field corn" includes a broader classi- 
fication. Read the fine print carefully for possible restrictions and limitations. 

CAUTION: BEFORE USING PESTICIDES, READ AND HEED THE LABEL. 



SPECIAL MEETING ANNOUNCEMENTS 



CORN ROOTWORM INSECTICIDE DEMONSTRATION PLOTS 

We will examine roots and count worms per plant for different insecticides applied at 
planting and during cultivation. Come and help make these counts to determine control 
with different insecticides. It will be a regular "rootworm search party." 

July 8, Livingston County : 1:00 p.m., Barth Farm. Go east of Pontiac on Route 116. 

Between Graymont Road and Flanagan on south side of road. 

July 9, Warren County : 1:30 p.m., Moore Farm. West of Roseville. Liquid insecti- 
cide in liquid fertilizer plots. Contact James McCurdy, 
Extension adviser, Monmouth for directions. 

July 10, Warren County : 9:00 a.m., Twomey Farm. Early planting. Go west of Rose- 
ville 5-1/2 miles on Route 116 to Smithshire Road. 

1:30 p.m., llennetent Farm. Late planting. 



-5- 

July 10, Stark County : 9:00 a.m., Cox Brothers Farm. South of Wyoming on Route 91 

to curve (about 2 miles) and west 1/2 mile on side road. 

July 11, Knox County : 9:00 a.m., Maurice DeSutter Farm. South of Woodhull 2 miles 

and west 1/2 mile. 

July 14, DeKalb County : 9:00 a.m., John L. Pigott Farm. North of DeKalb on 1st Street 

to Rich Road and west 1/2 mile. 

July 14, Hancock County : 1:00 p.m., Crose Farm. 3 miles east of Carthage, north on 

blacktop to first turn east, 1/2 mile. 

July 15, McHenry County : 9:00 a.m., Earl Hughes £, Sons Farm. About 5-1/2 miles north- 
west of Woodstock on the Dunham Road, just off Route 14. 

July 16, Boone County : 9:00 a.m., Nelson Farm. On the road east of Chrysler plant, 

just south of interstate highway. 

1:50 p.m., Flanders Farm. Liquid insecticide in fertilizer. 
North on Route 176 to Blaine Road, east to Blaine, north 
1 mile, and west 1/2 mile. Up long lane. 

July 16, JoDaviess and 

Stephenson Counties : 8:30 a.m., Cecil Creighton Farm. North of Stockton, 3 miles 

north of Route 20 on Route 78 and 1-1/2 miles east. 

July 17, Carroll County : 8:30 a.m., Woesnner Farm. East of Shannon 3 to 4 miles and 

north 1/2 mile. 

Rayner Moser Farm. Liquid insecticide in liquid fertilizer. 
In the afternoon after completion of Woesnner field counts. 
West of Milledgeville on Route 88 to curve north. East side 
of road. 

July 18, Ogle County : 8:30 a.m., Hugh Hermes Farm. On Route 2 east of Sterling. 

First farm on north side of road, west of Emerald Hills 
Country Club. 

July 18, Bureau County : 8:30 a.m., Anson Farm. East edge of Dover on Route 54. 

BRING YOUR POCKET KNIFE TO SPLIT ROOTS FOR "WORM SEARCH." 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Rosooe Kandell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural 
History Survey. 

WEEDS; E.L. Knake, Department of Agronomy. 

AG COMMUNICATIONS : Del Dahl. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



Ss. / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URB ANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




JSECT. WEED & PL A NT DISEASE SURVEY BULLETIN 



rE/COUNTY/LOCAL GROUPS/US. DEPARTMEMT OF AGRICULTURE COOPERATING 



• HIT OF eras 



~: 



FOR IMMEDIATE RELEASE 



LIBRARY 



No. 16, July 11, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



CORN INSECTS 

Fall armyworms are damaging late-maturing com, particularly in the southern sections 
of the state. These dark -brown to dull-green, smooth-skinned worms feed in the whorl, 
giving plants a ragged appearance as the leaves emerge. A series of plants in a row 
will show damage, and these patches of infested plants will usually be over the entire 
field. The adult moths deposit a cluster of eggs on one plant; after hatching, the 
worms move to adjacent plants. You will find only one worm per plant since they eat 
one another. 

In general, infestations are light and control is not needed. Treatment is justified 
in fields having 20 percent or more of the plants infested. Before applying insecti- 
cides, be sure the worms are still present, and that most of them are not more than 
1-1/4 inches long. IVhen they reach about 1-1/2 inches, they are mature; at that size, 
they stop feeding, drop to the ground, enter the soil, and pupate. 

For control, use granules of either carbaryl (Sevin) or toxaphene at 1-1/2 pounds of 
actual chemical per acre. Sprays provide erratic results, so the granular form is 
preferred. Do not feed toxaphene -treated forage to dairy cattle. Do not feed toxaphene- 
treated corn as silage to livestock fattening for slaughter. Corn treated with toxa- 
phene granules may be fed as stover to livestock to within 28 days of slaughter. 

First-generation European corn borers are pupating in the southern sections, and second- 
generation moths will begin to emerge this week (July 13). Check late-maturing corn for 
whorl damage --the last week of July and early August. 

In the central section, the borers are just beginning to enter the stalk, and it will 
soon be too late (end of the week of July 13) for effective control. Occasional small 
borers can still be found, along with those about half grown. Between 10 and 50 per- 
cent of the plants are infested with borers in the more-mature fields in this area, 
representing about 0.5- to 2-percent yield loss in these fields. Occasional fields 
have 70 to 80 percent of the plants infested. These can be profitably treated, if it 
is done immediately. 

In the northern section, populations appear to be lower. The more-mature fields have 
between 5 and 30 percent of the plants infested. The borers are still small and have 
not yet tunnelled into the stalks. 



-2- 

In general, there is a light to moderate number of corn borers in most of the more- 
mature fields (over half the acreage) throughout the state. Corn borers are also 
surviving in crops other than corn. Most hollow-stemmed weeds, small grains (like 
oats), certain vegetables, and even flowers (as well as many other plants) are suit- 
able hosts for corn borers. A report was received this week of potatoes in a home 
garden being severely damaged by corn borers. With good survival of this first 
generation, we could experience severe second-generation corn borer problems in many 
of the late-maturing fields. 

Corn rootworm larvae are increasing in number as the hatch of overwintering eggs con- 
tinues - ! Untreated plants in one of our demonstration fields averaged 13 worms per 
plant. Approximately 4 percent of the larvae have pupated in the central section. 
Egg-hatch is expected to continue for another 2 to 3 weeks, and the number of larvae 
will continue to rise during the next week or two- -then level off as more larvae reach 
the pupal stage. Damage to roots is beginning to show and will become progressively 
worse over the next 2 to 3 weeks . Rootworm development is about a week later than 
last year. 

Except for extreme conditions, it is generally too late to apply a basal treatment 
off the cultivator, since corn plant breakage and root pruning would be too great. 
The prospects of effective control by broadcasting the insecticides without culti- 
vation are not good. 

Corn leaf aphids are beginning to appear on corn in the central section. Individual, 
winged aphids were found on a few plants. These winged females will now give rise to 
young -producing, small colonies of aphids within a few days. Aphid predators like 
lady beetles, aphis lions, and insidious flower bugs are present. These predators 
will feed on the developing aphids. It is too soon to predict the severity of corn 
leaf aphid infestations. 

Corn leaf aphids suck the juices from the plants causing the ears to be stunted and 
shriveled. Injury to the plants usually occurs just prior to and during tasseling. 

Early treatment is best. Treatment is warranted when corn is in the late-whorl to 
early tassel stage and when 50 percent or more of the plants have a light to moderate 
number of aphids. At the latest, treatment should be made prior to brown silks. 

Spray treatments by ground or air, with 1 pound of malathion or diazinon or 1/4 pound 
of methyl parathion per acre, are effective. Allow 5 days for malathion, 10 days for 
diazinon, and 12 days for methyl parathion between treatment and harvest for grain, 
ensilage, or stover. If corn is in the late-whorl stage, seed producers may prefer 
to use 1 pound per acre of either diazinon or phorate (Thimet) as granules. To 
avoid potential hazards to detasselers, use phorate only on male-sterile corn. 

Common stalk borers can still be found in corn plants along the edges of fields. 
They come from the weeds and grasses bordering on these fields . This is one of the 
heaviest years on record for stalk borer. Preliminary damage studies conducted 
last year by Stephen Sturgeon, Survey Entomologist, showed a yield reduction of 37 per- 
cent for damaged plants, compared to undamaged plants in the same field. Only a small 
percentage of the total plants are generally infested. By the time the damage is 
found, the worms are deep in the whorl and control is difficult. It would help to 
keep weeds and grasses bordering the cornfields well mowed in August and September, 
thus discouraging stalk-borer moths from laying their eggs for next year's crop of 
worms . 



o- 




SOYBEAN INSECTS 

Seed com maggots continue to damage a few fields of late -emerging soybeans. Skips 
appear in the row of damaged fields. Small, white maggots can usually be found in- 
side the damaged seed. It is too late to control the maggot when damage is observed. 
The warm, wet weather should help slightly damaged plants to recover. 

HOMEOWNER INSECT PROBLEMS 

Millipedes are moving into homes from shrubbery beds, lawns, storm 
sewers, and nearby wasteland with a heavy trash cover. These mi- 
grations are somewhat earlier than normal (August and September), 
and are probably the result of recent heavy rainfall. It is usually 
the cool weather that causes them to seek shelter in homes. These 
brown or grey, hard-shelled, slow-moving, worm- like animals have 
two legs per body segment. They are sometimes called "thousand- 
leggers," and will curl up in a tight coil when disturbed. Although 
harmless, they make a general nuisance of themselves in the home, 
Millipede clustering in basements and garages. 

In cases of heavy migrations, spray lawns and shrubbery beds with carbaryl (Sevin) , 
diazinon, or trichlorfon (Dylox) . This provides a barrier zone in which the millipedes 
are killed, and prevents them from gaining access to the house. If migrations persist, 
repeat the treatment in a week or two. For minor problems, spray shrubbery beds and 
a 5- to 4-foot wide area around the foundation of the house for control. The general 
lawn treatment will also control sod webworms and leafhoppers, but it is ineffective 
against grubs. 

Picnic beetles are becoming numerous at the present time. These black beetles with 
four yellow spots are attracted to food odors and decaying or overripe fruit and vege- 
tables. They are commonly found around garbage cans and on window screens. 

For control in home yards, harvest fruits and vegetables before they become overripe. 
Dispose of any spoiled produce. To kill the adult beetles, spray with malathion, 
diazinon, or carbaryl (Sevin) in and around garbage cans. Spraying shrubbery and tall 
grass with the same insecticides before a cookout will greatly reduce the number of 
these beetles. Follow directions on the label. Check plants that may be injured if 
sprayed with the insecticide you are using. Either 0.1-percent pyrethrin or 0.5-percent 
dichlorvos (DDVP) spray in pressurized cans will give a quick knockdown of beetles that 
suddenly move into an area. 



WEEDS 



Wet is the word from all over the state. If you did not complete your cultivation 
before the rains, corn and beans are likely to be too large in many fields to finish 
cultivating when it dries up. 

2,4-D can still be helpful in many late-maturing cornfields. So far, fewer farmers 
have reported 2,4-D injury to corn this year than last. A few areas, however, have 
reported rather severe injury --some where 2,4-D was sprayed July 5 and 4 during 
exceptionally hot and humid weather followed by wind. 

Avoid spraying 2,4-D during such hot, humid periods. Be sure application rates are 
correct. We suggest 1/6 lb. /A., low-volatile ester; 1/4 lb. /A. , high-volatile ester; 
or 1/2 lb. /A. of amine. (If you're using a 4 lb. /gal. concentrate, 1/4 lb. is a half 
pint and 1/2 lb. is one pint.) 



-4- 

Iligh- clearance equipment will be needed in many fields and "drop nozzles" will usually 
be necessary. If nozzles are directed in toward the row, reduce the amount of 2,4-1) 
;md adjust the nozzles to prevent too much spray from being applied directly on the 
corn. Do not spray from the tasseling to dough stage. Because 2,4-1) can make corn 
brittle for a week or so, it is best not to treat if windstorms can be expected during 
the next week. 

There is always some risk involved when using 2,4-D. So follow the precautions care- 
fully and realize that there may still be some risk beyond your control. 

For the state as a whole, the benefits from 2,4-D will far exceed the disadvantages. 
Having weeds at harvest has its risks, too. 

Forget about using atrazine and oil this late. If atrazine has been applied as late 
as July, do not plant soybeans next year, because of the likelihood of residue. Most 
grass weeds are now too large for control with atrazine postemergence. 2,4-1) is more 
economical and practical for most broadleaved weeds now. 

The rainj have brought on late small weeds, both between and in the rows. With high 
populations and narrow rows, corn and beans should provide enough shade to discourage 
weed growth in many of these fields. However, some small weeds may come along; 
although not very competitive, they can produce seed. 2,4-D is still best for late- 
germinating broadleaved weeds in corn. 

A few farmers have considered Dowpon or Lorox for grass, but not many of them have 
appropriate equipment; and care is needed to avoid corn injury. If very much Dowpon 
contacts corn leaves , it can translocate in the plant and adversely affect ear and 
grain development. To be effective, Lorox should be applied before the weeds are 
8 inches high- -preferably when they are 5 or 6 inches high. Corn should be at least 
15 inches high and you must carefully direct the spray to avoid corn injury. 

Postemergence herbicides for soybeans were discussed in the Insect, Weed, and Plant 
Disease Survey Bulletin No. 12 (June 15, 1969), on page 6. The portion on 2,4-D 
should have read 2,4-DB . You can still use 2,4-DB for really serious cocklebur, 
annual morning glory, and giant ragweed in soybeans. But check the timing and rates 
carefully. 

There seems to be increased interest in Banvel this year. It is approved only for 
corn up to 56 inches high and has done well on smartweed and many other broadleaved 
weeds. Corn has relatively good tolerance to Banvel postemergence, but the problem 
of possible injury to nearby plants (such as soybeans) still discourages its use. 

Because of damage from 2,4-D plus atrazine and oil, we have suggested not to add 
Banvel to an atrazine -and -oil mixture. Atrazine does so well on smartweed that there 
is little reason to add the Banvel. Banvel has been cleared for pasture and range- 
land use too. It is better than 2,4-D on some perennial weeds. 

There is no waiting period between treatment and grazing for animals other than 
dairy cows, but do not graze meat animals in treated fields within 50 days ol~ 
slaughter. And do not use the seed from treated grass for feed or food. 

The restrictions on dairy cattle grazing and dry-hay usage are shown on the following 
page. 



Treated Pasture Grasses Grazed by Dairy Cattle 



Waiting period 



Rates 



Lb. acid equivalent/acre Quart/acre (lb. /quart) 



7 days 
21 days 
bO davs 



to 1/2 
1/2 to 1 

1 to 8 



1/2 

1/2 to 1 

1 to 8 



Treated Pasture for Dry-Hay Usage 



Rate 



Wait to cut 



Lb. acid equivalent/acre 



57 days 
51 days 
70 days 
90 davs 



to 1/2 
1/2 to 1 

1 to 2 

2 to 8 



CAUTION: BEFORE USING PESTICIDES, READ AND HEED THE LABEL 

SPECIAL MEETING ANNOUNCEMENTS 

CORN ROOTWORM INSECTICIDE DEMONSTRATION PLOTS : We will examine roots and count worms 
per plant for different insecticides applied at planting and during cultivation. Come 
and help make these counts to determine control with different insecticides. It will 
be a regular "rootworm search party." 



July 14, DeKalb County : 

■ July 14, Hancock County : 

July 15, McHenry County : 

July 16, Boone County : 



July 16, JoDaviess and 
Stephenson Count icsT 



9:00 a.m., John L. Pigott Farm. North of DeKalb on 1st Street 
to Rich Road and west 1/2 mile. 

1:00 p.m., Crose Farm. 5 miles east of Carthage, north on 
blacktop to first turn east, 1/2 mile. 

9:00 a.m., Earl Hughes 5 Sons Farm. About 5-1/2 miles north- 
west of Woodstock on the Dunham Road, just off Route 14. 

9:00 a.m., Nelson Farm. On the road east of Chrysler plant, 
just south of interstate highway. 

1:30 p.m., Flanders Farm. Liquid insecticide in fertilizer. 
North on Route 176 to Blaine Road, east to Blaine, north 
1 mile, and west 1/2 mile. Up long lane. 



8:30 a.m., Cecil Creighton Farm. North o\' Stockton, 5 miles 
north of Route 20 on Route 78 and 1-1/2 miles cast. 



July 17, Carroll County : 



July IS, Ogle County : 



8:30 a.m., Woesnner Farm. East of Shannon 3 to 4 miles and 
north 1/2 mile. 

Rayner Moser Farm. Liquid insecticide in liquid fertilizer. 
In the afternoon after completion of Woesnner field counts. 
West of Milledgeville on Route 88 to curve north. East side 
of road. 

8:30 a.m., Hugh Hermes Farm. On Route 2 east of Sterling. 
First farm on north side of road, west of Emerald Hills 
Country Club. 



July 18, Bureau County : 8:30 a.m., Anson Farm. East edge of Dover on Route 34. 
BRING YOUR POCKET KNIFE TO SPLIT ROOTS FOR "WORM SEARCH." 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urbana-Champaign and Illinois Natural 
History Survey. 

WEEDS: E.L. Knake and M.D. MoGlamery, Department of Agronomy . 

AG COMMUNICATIONS: Del Dahl. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



./Hs 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 

ATE/COUNTY/LOCAL GROUPS/US. DEPARTMEMT OF AGRICULTURE COOPEHAflNQ 






FOR IMMEDIATE RELEASE 



No. 17, July 18, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



INSECTS 



CORN INSECTS 

Fall armyworms can still be found in some medium -maturing fields and in most late- 
maturing cornfields. Occasional fields have 20 to 50 percent infested plants, but 
in most fields the range is between 5 and 15 percent infested plants. 

In the southern section, many of the larvae have already matured, stopped feeding, 
and pupated. Additional generations could still present further problems in late- 
maturing fields. After corn has tasseled, fall armyworms will attack the developing 
ears (like corn earworms) , and some larvae will be present in ears until frost. 

In the central and northern sections, the larvae were about half grown to nearly 
full grown this week, and pupation will now progress rapidly. Treatment is justified 
in fields having 20 percent or more of the plants infested. Before applying insecti- 
cides, be sure the worms are still present, and that most of them are not more than 
1-1/4 inches long. When they reach about 1-1/2 inches, they are mature; at that size, 
they stop feeding, drop to the ground, enter the soil, and pupate. 

For control, use granules of either carbaryl (Sevin) or toxaphene at 1-1/2 pounds of 
actual chemical per acre. Sprays provide erratic results, so the granular form is 
preferred. Do not feed toxaphene- treated corn as forage to dairy cattle. Do not 
feed toxaphene- treated corn as silage to livestock fattening for slaughter. Corn 
treated with toxaphene granules may be fed as stover to livestock to within 28 days 
of slaughter. There are no restrictions for carbaryl. 

Corn rootworm larval populations continue to increase as hatch of overwintering eggs 
reaches its peak, particularly in the northern section. As eggs continue to hatch, 
the number of larvae is expected to increase or hold about the same for the next 
2 weeks. Pupation of larvae is progressing rapidly in many fields, and a few adults 
have emerged in the western and central sections. Pupation reached 4 percent this 
week in northern sections, but will progress rapidly from now on. 

Damage to roots is becoming more evident, and goosenecking of plants as a result of 
larval feeding is now evident in a few fields. This will become increasingly evident 
in the weeks ahead, especially if strong winds or rains accompanied by strong winds 
occur. Thus far the insecticides recommended for resistant rootworms as planting- 
time and as basal treatments off the cultivator have generally provided good to ex- 
cellent control of larvae in spite of the heavy rainfall in some areas. 



-2- 

Both the yellow- to-tan to pale-green northern corn rootworm adults and the yellow- 
and-black-striped western corn rootworm adults (northwestern section) will be found 
emerging and feeding on fresh silks during the next several weeks. These insects 
can reduce pollination. Particularly watch late-planted fields as these fields are 
most likely to reach the early-silk stage at the time of peak adult rootworm popula- 
tions . 

Treatment is justified if there are 5 or more beetles per plant and if not over 
50 percent of the plants have silked. Sprays of carbaryl (Sevin) , malathion, or 
diazinon at 1 pound of actual chemical per acre or 1/4 pound of actual methyl para- 
thion per acre are effective. Methyl parathion should be used by experienced appli- 
cators only. Allow 5 days between treatment and harvest for malathion, 10 days for 
diazinon, and 12 days for methyl parathion. Carbaryl has no waiting period. 

First-generation corn borers are pupating and emerging as moths in the southern half 
of the state. Check late-maturing fields for whorl feeding in late July and early 
August. 

Pupation is just beginning in the northern half of the state, and it will be another 
week before the first moths begin to emerge. Borers ranged from small to nearly 
full grown, with most of them half to two-thirds grown. They are now beginning to 
tunnel into stalks, and most of them will enter the stalk within the next week. 
Check late-maturing fields for whorl damage or egg masses in early to mid-August. 

Second- generation infestations in late-maturing fields can be handled in the same 
way as the first-generation problems. If 75 percent or more of the plants have 
whorl- leaf feeding, apply carbaryl (Sevin) or diazinon granules. If the corn has 
tasseled, look for egg masses. If the average is 1 or more per plant, apply an in- 
secticide after a few eggs have hatched. 

Commercial applicators may prefer to use parathion at 1/2 pound per acre. Sprays by 
air or with high-clearance ground equipment are effective on tasseled corn. Allow 
10 days between treatment and harvest when using diazinon and 12 days for parathion. 
Carbaryl has no waiting period. 

Corn leaf aphids are slowly increasing in numbers, but populations are still light. 
Individual aphids and a few colonies were observed in about 1 to 5 percent of the 
plants in fields in the central section. Many fields of corn are now coming into 
tassel, and with aphid numbers low it is doubtful that these fields will have a 
serious problem. This is particularly true in areas that have ample soil moisture. 
In areas with low soil moisture, however, a late buildup of aphids could still be 
serious. In general, it does not appear that the corn leaf aphid will present as 
severe a problem as it did in 1966 and 1968. It is still early for reliable pre- 
dictions, and the next week or two will more definitely determine the situation. 
Continue to check fields that have not yet reached the early tassel stage for aphid 
buildup. Treatment is warranted when corn is in the late-whorl to early tassel 
stage and when 50 percent or more of the plants have a light to moderate number of 
aphids. At the latest, treatment should be made prior to brown silks. 

Spray treatments by ground or air, with 1 pound of malathion or diazinon or 1/4 pound 
of methyl parathion per acre, are effective. Allow 5 days for malathion, 10 days for 
diazinon, and 12 days for methyl parathion between treatment and harvest for grain, 
ensilage, or stover. Methyl parathion should be applied by experienced applicators 
only. If corn is in the late-whorl stage, seed producers may prefer to use 1 pound 
per acre of either diazinon or phorate (Thimet) as granules. To avoid potential 
hazards to detasselers, use phorate only on male-sterile corn. 



Large numbers of true armyworm moths have been flying northward within recent days. 
Be on the lookout during the next week or two for the presence of armyworm larvae 
in grassy cornfields in the northern section. The worms feed first on the grass and 
then move to the corn plant. 

For infestations, apply carbaryl (Sevin) or toxaphene at 1-1/2 pounds of actual 
chemical per acre. Do not feed toxaphene-sprayed corn as forage to dairy cattle or 
livestock fattening for slaughter . Corn can be harvested as grain without any re- 
strictions. There are no waiting periods or restrictions for corn treated with 
carbaryl. 

SOYBEM1 INSECTS 

Grasshoppers have been observed feeding heavily on the marginal rows of soybeans. 
They have recently moved from fence rows, ditchbanks, and roadsides. Migrations of 
grasshoppers will continue from these areas particularly if conditions are dry. If 
large numbers are observed, spray the bordering grassy areas with 3/4 pound of carb- 
aryl (Sevin) or 1-1/2 pounds of toxaphene per acre. 

FORAGE INSECTS 

Meadow spittlebug adults can be found in clover, alfalfa, and soybean fields. These 
large, wedge-shaped, tan-to-brown- to-black, leafhopper-type insects (about 1/4 inch) 
jump with an audible "pop" when disturbed. The females lay their eggs during late 
August and September in clover and alfalfa fields. These eggs will hatch next spring. 
The adult spittlebugs will continue to be present in these fields until mid- to late- 
September. Their feeding is of little importance. 

HOMEOWNER INSECT PROBLEMS 

Sod webworm moths are beginning to appear in increasing numbers, particularly in 
southern and central sections. These buff -colored moths rest in shrubbery and tall 
grass during the day and are seen flying in a zigzag pattern over the lawn near dusk. 
These are the second-generation moths that are laying their eggs at this time. If 
you find large numbers of these moths in your yard, plan to treat your lawn with an 
insecticide about 2 weeks later. Usually target dates for treatment are late July in 
southern sections, early to mid- August in the central section, and mid- to late 
August in the northern sections. 

The larvae of the webworm are gray worms with brown spots and black heads. They are 
about an inch long when full grown and live for 5 to 4 weeks in the worm stage. The 
worms live in silken-lined burrows in the thatch of the lawn, clipping off grass 
blades at the base. Brown spots appear in the lawn and large numbers of robins will 
move in to feed on the larvae. By this time, it is usually too late for control. 

For control of webworms, apply a spray or granules of 2 pounds of actual carbaryl 
(Sevin), 1 pound of actual diazinon, or 1-1/4 pounds of actual trichlorfon (Dylox) 
per 10,000 square feet. Use about 25 gallons of water to distribute the insecti- 
cide over the 10,000 square feet when spraying. Do not water the lawn for at least 
5 days after treatment. If heavy rains occur within 5 days of application, a re- 
peat treatment may be needed. 

Tomato fruitworms (same as corn earwormj and tomato hornworms are common in tomatoes 
particularly in southern sections. Tomato fruitworms are more numerous than normal 
this year, and damage to developing tomatoes will likely be severe during August and 



even into September over much of the state. Sprays of carbaryl (Sevin) , using 
2 tablespoons of the 50-percent wettable powder per gallon of water, are effective. 
When worms are present, spray the tomato plants every 5 to 7 days. There is no 
waiting period between treatment with carbaryl and harvest of the tomatoes . 

.An assortment of insect pests like flea beetles , bean beetles , striped and spotted 
cucumber beetles , and other leaf- feeding beetles can be found attacking vegetables 
in home gardens . Carbaryl (Sevin) or malathion will control these insects. Use 
2 tablespoons of 50 -percent carbaryl (Sevin) wettable powder or 2 teaspoons of 50- 
to 57-percent malathion liquid concentrate per gallon of water. Follow label 
directions for the waiting period between spraying and harvest and for other pre- 
cautions. Make the applications in early evening to avoid injury to bees. 



WEEDS 



Weeds are still bad news in many fields where adequate cultivation and spraying 
have not been possible because of wet weather. 

2,4-D is about the only spray to consider for corn at this late date. Usually we 
are not very enthusiastic about late spraying, but much more than normal may be 
justified this year. 

Most 2,4-D labels say, "Do not apply from tasseling to dough stage." This state- 
ment is apparently based on early research which showed that spraying at certain 
critical stages might interfere with development of grain. In one Iowa study, 
2,4-D was sprayed on corn plants at various stages. Applying 2,4-D when tassels 
were beginning to emerge resulted in inhibition of ear shoots . And application of 
2,4-D 1 to 4 days before silk emergence caused severe inhibition of seed set on 
the developing ear. 

Each year, 2,4-D causes some brittleness and breakage of corn, some onion- leafing, 
and some malformation of brace roots. But we have had very few reports from 
farmers' fields of 2,4-D affecting ear and grain development. Perhaps this is 
partly because of precautions to avoid spraying during the critical period, more 
resistant hybrids, and minimal amounts of 2,4-D applied directly to the corn leaves. 

But it still seems safest to avoid spraying during the critical stages, especially 
during early development of the ear shoots (this is about the time tassels begin 
to emerge) and just before silks emerge. 

Silks are usually pollinated very soon after they emerge. After fertilization and 
when the silks are drying, there is apparently less risk of injury from 2,4-D. 
However, fertilization is followed by a period of rapid nutrient uptake and movement 
of food materials to the grain. Stress conditions or injury of various kinds during 
this stage may interfere with normal kernel development. 

Although weeds will usually be large, "tough," and harder to kill with 2,4-D, 
spraying can be resumed after the grain is well on its way and in the dough stage . 
The dough stage begins about 5-1/2 weeks after silks begin to emerge. During the 
dough stage, the silks are dry, kernels are still developing, and starch is 
accumulating. 

But remember that by the thne corn reaches the dough stage, many weeds already will 
have done most of their damage through competition for nutrients and moisture. Many 
weed seeds will also be developed sufficiently to be viable. The late spraying may 
make harvesting a little easier, however. 



Banvel use appears to have increased this year. Reports have started coming in of 
injury to nearby soybean fields. Symptoms are cupping and crinkling of soybean 
leaves. Some of the top leaf buds may not open normally. Yields may be affected, 
but not always as much as you would anticipate by the appearance of the field. 
There's not much you can do except to get a good book on how to win friends and in- 
fluence people. 

NOT FOR PUBL I CAT I ON --SPECIAL NOTE TO COUNTY EXTENSION ADVISERS 

Fly control at county fairs : We have modified the following portion of a Purdue 
Insect Newsletter on this subject to fit Illinois conditions: 

1. Fair officials will need to be sure that manure, garbage, refuse, and soft- 
drink bottles are removed from the grounds every day. This is a must. 

2. A few days before the fair starts, spray livestock sheds, outdoor privies, empty 
food tents, and other buildings that may harbor flies with dimethcate (Cygon) , 
diazinon, or ronnel (Korlan) . A farm crop sprayer, equipped with a lead of hose 
and a spray gun, can be used for this purpose. Apply the spray to the ceilings 
and walls to the point of runoff. Most rotary pumps on these sprayers can be 
adjusted to operate at 250 to 300 pounds of pressure. If the water pressure is 
good (50 p.s.i. or more), a spray gun that fits on the end of the hose will do 

a good job of applying the insecticide. 

Sprays should also be applied to refuse containers, garbage cans, and the like 
before and during the fair. A couple of young boys with compressed-air tank 
sprayers can do this job. 

5. Flies are attracted from great distances to animal waste and food odors. These 
flies are not killed until they land on a treated surface. For quick knockdown 
of these incoming flies in animal shelters and other places, use a small electric 
fogger with oil- or water-base pyrethrum or dichlorvos (DDVP) . These fogs are 
best applied in the early morning when no people are around. Animals need not 
be removed, although horses may be frightened by the fog. 

4. Urge that food stands keep some pyrethrum or dichlorvos in a pressurized spray 
can for quick kill of adult flies. These sprays should be used at night after 
the stands close. The local health department should insure that all stands 
maintain the required standards of cleanliness. 

This weekly report was prepared as follows: 

INSECTS: H,B. Petty, Steve Moore, Rosooe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture , Urb ana- Champaign and Illinois Natural 
History Survey. 

WEEDS: E.L. Knake and M.D. MoGlamery, Department of Agronomy. 

AG COMMUNICATIONS: Del Dahl. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



/J^ 



L 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECX WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



I l - ■ ' 



..'. A L. .- 



rCD I lOyQ 
FOR IMMEDIATE RELEASE No. 18, July 25, 1969 

; ' : -- M i ■ 

This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) 3 along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



CORN INSECTS 

Armyworms are invading cornfields in western and northern Illinois . The moths , abundant 
for the past 2 to 3 weeks, deposited eggs on grasses in cornfields, on oats in lodged spots, 
and on oats and grasses in government acres. These worms have fed for some time, have 
stripped the grasses, and are now migrating in search of food. If they migrate into a 
cornfield, they often strip the plants, leaving only stalks and midribs. When corn is 
small , this leaf loss may not be serious , but at this late date , it is as plants are under 
stress during pollination and silking. Thus damage could be serious. Fat worms, 1-1/4 to 
1-1/2 inches long, are mature and have already done their damage; but if you have many 
small worms in a field, an insecticide for control may be wise. Above all, examine plants 
land soil carefully for worms before treating. Be sure you have a problem and do not treat 
just to be treating. Watch for shriveled or dying worms. Virus disease, wasp parasites, 
and fly parasites may help control this pest. 

If you need an insecticide, use 1-1/2 pounds of actual toxaphene or carbaryl (Sevin) per 
acre as a spray. Do not apply carbaryl [Sevin) near bee yards or on pollinating plants 
frequented by bees. Do not apply toxaphene to, or adjacent to, fish-bearing waters. Do 
lot feed toxaphene -treated com for ensilage or stover. 

Fall armyworm damage to corn is still visible but plants are recovering. Usually several 
plants in one spot are affected. Leaves are fed upon, and plants have a ragged appearance. 
3ut the worms have now matured and are conspicuous by their absence. A later generation 
nay enter ears of late corn, alfalfa, or soybeans. However, this damage from the later 
veneration is usually not severe except in extremely late corn. 

Control is not recommended when the worms are gone, but if you find these worms in the 
diorl of the plants , you can control them with granules of either carbaryl (Sevin) or 
".oxaphene at 1-1/2 pounds of actual chemical per acre. Sprays provide erratic results, 
;o the granular form is preferred. Do not feed toxaphene- treated corn as forage to 
lairy cattle. Do not feed toxaphene -treated corn as silage to livestock fattening for 
slaughter. Corn treated with toxaphene granules may be fed as stover to livestock to 
rithin 28 days of slaughter. There are no restrictions for carbaryl. 

]orn rootworms have begun to emerge as adults, but in the meantime the worms still present 
n the soil are feeding on the roots; plants in many fields are tipping over because of 
his root pruning. If moisture continues to be plentiful, the plants will partially re- 
:uperate, but, if moisture becomes short, damage will be severe. 



Our next concern will be the green, yellow, or striped rootworm beetles that feed on 
silks. If they are abundant in fields less than 50 percent silked, damage to pollina- 
tion will be measurable. Treatment is justified if there are 5 or more beetles per 
plant and if not over 50 percent of the plants have silked. Sprays of carbaryl (Sevin), 
malathion, or diazinon at 1 pound of actual chemical per acre or 1/4 pound of actual 
methyl parathion per acre are effective. Methyl parathion should be used by experienced 
applicators only. Allow 5 days between treatment and harvest for malathion, 10 days for 
diazinon, and 12 days for methyl parathion. Carbaryl has no waiting period. 

Corn leaf aphids are more plentiful than last week, but the situation is not alarming. 
In most fields infestations ranged from to 6 percent this week. In one field we found 
15 percent of the plants infested. Infestations are much lower than in 1966 and 1968. 

Aphids multiply fastest when corn is in the pretassel or late-whorl to brown-silk stage. 
Since most of our corn is now beyond this susceptible stage or rapidly approaching the 
nonsusceptible stage and aphid populations are low, we do not anticipate a severe general 
problem. However, examine late corn, particularly in the drier areas of Illinois. Aphid 
populations may still increase and damage these fields severely. Treatment is warranted 
when corn is in the late -whorl to early tassel stage and when 50 percent or more of the 
plants have a light to moderate number of aphids. At the latest, treatment should be 
made prior to brown silks. 

Spray treatments by ground or air with 1 pound of malathion or diazinon or 1/4 pound of 
methyl parathion per acre are effective. Allow 5 days for malathion, 10 days for diazinon, 
and 12 days for methyl parathion between treatment and harvest for grain, ensilage, or 
stover. Methyl parathion should be applied by experienced applicators only. If corn 
is in the late-whorl stage, seed producers may prefer to use 1 pound per acre of either 
diazinon or phorate (Thimet) as granules. To avoid potential hazards to detasselers, use 
phorate only on male -sterile corn. 

European corn borers are in between broods except in extreme southern Illinois, where 
second-generation borers were found this week. In northern Illinois expect second- 
generation moth flight to begin about August 5 to 10; in central Illinois, August 1 to 
10. Moths will be present in southern Illinois from now on. 

Insecticide applications may be justified to control second -generation borers in late 
corn this year. In southern Illinois check late fields now. 

Second-generation infestations in late -maturing fields can be handled in the same way as 
the first-generation problems. If 75 percent or more of the plants have whorl-leaf feed- 
ing, apply carbaryl (Sevin) or diazinon granules. If the corn has tasseled, look for egg 
masses. If the average is 1 or more per plant, apply an insecticide after a few eggs 
have hatched. 

Commercial applicators may prefer to use parathion at 1/2 pound per acre. Sprays by air 
or with high -clearance ground equipment are effective on tasseled corn. Allow 10 days 
between treatment and harvest when using diazinon and 12 days for parathion. Carbaryl has 
no waiting period. 

Southwestern corn borers are present in late corn in extreme southern Illinois. Late 
fields averaged 21 percent stalk infestation in fields in the southern tip of Illinois 
this week. Examine these late plantings for this spotted worm. Carbaryl or diazinon 
granules may be helpful in control if you find 25 percent or more of the plants infested. 



Picnic beetles are invading corn silks in central and northern Illinois. They are usuallv 
attracted to the rotting plant material in fields that have been damaged by other insects. 
Ve doubt that they are damaging pollination and do not consider them a primary pest of 
;orn. Under certain conditions, they may feed on ear tips that have been exposed. 

Voollybear caterpillars of various colors may soon be found feeding in the silks or on the 
Leaves . Thus far they have never been of economic importance. 

SOYBEAN INSECTS 

j ras shoppers seem to have survived the earlier rains successfully and are present in some 
legume and soybean fields. They can also be found in fence rows and ditch banks. If 
large numbers are observed, spray marginal soybean rows and adjacent grassy areas with 
5/4 pound of carbaryl (Sevin) or 1-1/2 pounds of toxaphene per acre. 

iOMEOWNER INSECTS 

V'e have received several inquiries from small communities about mosquito control . The 
following control program is suggested: 

L. keep drainage ditches, roadside ditches, and storm sewers properly cleaned and drained 
to avoid water pockets. 

2. Remove grasses, weeds, lilies, and other vegetation from along the margins (5 feet from 
shore) of nearby ponds and lakes. Drain or fill nearby wet land areas if possible. 

Urge homeowners to eliminate standing water in their yards in such places as eaves, 
troughs, old tires, tin cans, children's toys, and like places. 

Spray tall grasses, weeds, and shrubbery in and around the community with malathion to 
eliminate adult mosquitoes. There are many insecticides that effectively kill mosquitoes. 
We have selected malathion first on the basis of safety and then effectiveness. It will 
kill mosquitoes for approximately 1 to 5 days after application depending on weather, 
and is no more toxic to man and animals than aspirin. Malathion has a somewhat notice- 
able odor, but in the diluted form used for mosquito spraying, it should net be objec- 
tionable . 

Malathion may be effectively applied by a conventional high-pressure sprayer, aircraft, 
mist blower, or fogger. Plan on applying approximately 1/2 pound of actual malathion 
per acre. 

i. Notify residents of the method, date, and time of application. Do not apply malathion 
to fish-bearing waters or water used for drinking purposes . 

irmyworms are extremely abundant in lawns in some areas. Carbaryl sprays can be used in 
aid around house yards if worms are devouring the grass and becoming a general nuisance, 
'o not spray if worms are mature. 

; 'icnic beetles are nuisances when they visit your picnic table. They also invade gardens 
here they attack fruits and vegetables damaged by weather or other insects. Thev partic- 
ilarly like to penetrate ripe tomatoes with growth cracks. 



These black beetles with the four ye How -to -orange spots on their backs are difficult to 
control. Sprays of carbaryl (Sevin) may be helpful. Use 2 table spoonfuls per gallon 
of water in your garden. Diazinon sprays around garbage containers and in some vegetables 
may also be helpful. Do not harvest tomatoes for at least 24 hours after application. 
Follow label directions for use in home gardens. 

Fall webworms are beginning to appear on shade trees. They spin webs around the ends of 
branches , especially of birch, ash, and elm. Tawny-colored hairy caterpillars skeletonize 
the foliage inside the webbing. They continue to extend the web to take in fresh foliage. 
Prune out infested limbs and burn webs where larvae are located, or break open web and 
spray with malathion at the rate of 2 teaspoonfuls per gallon of water. 



WEEDS 



2,4-D drifting to gardens . Each year 2,4-D affects some vegetables and fruits in adjacent 
or nearby cornfields. "Should the produce be eaten? In most situations it is probably 
all right. 

The LD50 for various 2,4-D formulations varies from about 375 to 850 mg./kg. For 2,4-D 
ester, the LD50 is about 650 mg./kg. --the equivalent of about 1 ounce per 100 pounds. So, 
if a 100-pound person consumes 1 ounce of 2,4-D ester, he should be concerned. The amount 
could be lethal . 

The amount of 2,4-D that drifts to a garden varies considerably with spray pressure, volume 
of water used, wind direction, and other factors. 

As an example, let's assume you apply the recommended rate- -1/4 pound of 2,4-D, or one- 
half pint of concentrate, per acre--to a cornfield. Assume that 25 percent--a highly 
exaggerated rate--of the 2,4-D drifts to the garden. Such a drift level would result in 
1 ounce (by weight) of actual 2,4-D being spread over a full acre, or 2 fluid ounces (4 
tablespoons) of the liquid 2,4-D concentrate on a full acre . 

This small amount of 2,4-D might have some effect on plants, but it is unlikely that it 
could cause an acute toxicity problem to humans. Only a portion of the 2,4-D would be on 
the edible plant parts and it would be impossible for one individual to consume the produce 
from an acre at one sitting. 

Of the 2,4-D that drifts to a garden, some will be deposited on the soil, some on the non- 
edible plant parts, and only a portion on some of the edible plant parts. 

2,4-D is not very persistent and usually decomposes rather fast during a few weeks of warm 
moist weather. Its effect on plants may be evident for some time, however. 

Accidental ingestion of the liquid concentrate because of improper storage and handling is 
the major concern. All concentrates should be properly stored and carefully handled, 
especially around children. 

Although eating plants affected by 2,4-D does not seem a cause for alarm, there are two 
other considerations. Some individuals may be allergic or particularly sensitive to certain 
herbicides just as some individuals are sensitive to bee stings, drugs, plants, and pollen. 
Little research has been done on this relationship for herbicides, so be careful. 



-5- 

Secondly, the psychological effect may be one of the most important aspects. A person may 
eat some affected vegetables or fruit and then start worrying or losing sleep. He may 
develop a sore throat or headache from some entirely unrelated cause and associate his 
discomfort with having eaten the produce. 

Strained relationships between neighbors is another problem. So it's best to use con- 
siderable precaution to avoid getting 2,4-D on gardens and ornamentals. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 

Special Announcements: 

MEETING TO RATE CORN ROOTS DAMAGED BY ROOTWORMS 

July 29 8:30 a.m. --noon . McHenry County. Louis Engelbrecht, Extension Adviser. 

Location : Earl Hughes § Sons Farm, northwest of Woodstock on Route 14 to Dunham 
road then west about 1 mile. 

Fifteen insecticide plots to be compared with roots from untreated plots. Lodg- 
ing also to be rated. 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Rosaoe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture , Urbana-Champaign and Illinois Natural 
History Survey. 

WEEDS: E.L. Knake and M.D. MoGlamery , Department of Agronomy. 

AG COMMUNICATIONS : Del Dahl. 

The information for this report was gathered by these people , staff members , county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT, WEED & PLANT DISEASE SURVEY BULLETIN 



rATE/COUNTY/LOCAL GROUPS/US. DEPARTMEMT OF AGRICULTURE COOPERATING 






I- - 



FOR IMMEDIATE RELEASE 



tt* 



'£a 



% - 1 



No. 19, August 1, 1969 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



CORN INSECTS 



True armyworms in corn rate the insect -of -the -week award. The problem area lies north 
of Route 36. They are damaging corn where grasses were thick in the row and cornfields 
planted adjacent to government acres which contain grasses or oats. The worms strip 
the lower leaves first, leaving only the stalk and midribs. Sometimes they chew silks 
and work the tip of the ear. 

Worms of all sizes were found this week (the worm stage lasts 2-1/2 to 3 weeks), with 
about 1/2 to 2/3 of them nearly full grown. The worms should begin to disappear as 
pupation progresses rapidly. The next generation of moths will roll on northward and 
should present no further problems in these same areas. 

Before applying an insecticide, examine the field closely for the presence of worms and 
assess the prospects for further damage. In many fields, the damage is confined to 
localized grassy spots. Virus diseases, wasp parasites, and fly parasites can reduce 
populations quickly. So, watch for shriveled or dying worms on the leaves. Diseased 
worms were observed in several fields this week. If the disease becomes widespread, 
worm populations will disappear almost overnight. 

If worms are still present, particularly many small to half -grown ones, and feeding is 
pronounced, apply 1-1/2 pounds of actual carbaryl (Sevin) or toxaphene per acre as a 
spray. Malathion at 1 pound of actual per acre is also effective. Do not apply carbaryl 
near bee yards or on pollinating plants frequented by bees. Carbaryl has no waiting 
period. Do not apply toxaphene on or adjacent to fish-bearing waters. Do not feed 
toxaphene -treated corn as ensilage or stover to dairy cattle or to livestock fattening 
for slaughter. Corn may be fed as grain from toxaphene -sprayed fields. Do not harvest 
corn treated with malathion as feed or forage for 5 days after treatment. 

Corn rootworm adults are beginning to emerge in cornfields, where they are feeding on 
silks. Species include the tan or pale-green northern, yellow and black striped western, 
and 12-spotted southern corn rootworms. Since adult emergence is just beginning, popula- 
tions can be expected to increase. In many of the problem fields, the corn is lodged 
(especially if rains and winds have occurred recently) and root damage is severe, due 
to feeding by the larvae. 



-2- 

If rootworm beetles are numerous, they can reduce pollination. Medium to late-maturing 
fields will likely be most seriously affected, since beetle numbers are likely to be 
higher in these fields during the critical pollinating period. Treatment is justified 
if there are 5 or more beetles per plant and if not over 50 percent of the plants have 
silked. Sprays of carbaryl (Sevin) , malathion, or diazinon at 1 pound of actual chemica 
per acre, or 1/4 pound of actual methyl parathion per acre are effective. Methyl para- 
thion should be used by experienced applicators only . Allow 5 days between treatment 
and harvest for malathion, 10 days for diazinon, and 12 days for methyl parathion. 
Carbaryl has no waiting period. 

If you want to estimate the prospects of rootworm problems for next year, make a check 
on the number of rootworm beetles and rootworm damage during the next week or two. If 
you find lots of beetles (5 or more per plant) , or if the roots are moderately to severe 
damaged, then there may be enough rootworms in the field to cause economic losses in 197 
if the field is planted to corn again. 

Notify your county extension adviser if you have had failures with one of the organic 
phosphate or carbamate insecticides used for the control of resistant rootworms. Also 
report any fields of first-year corn that have been damaged by rootworms. 

Corn leaf aphids are increasing slowly but populations are still not alarming. In most 
fields aphid infestations on plants ranged from 5 to 10 percent this week. One field 
was reported to have up to 30 percent of the plants lightly infested. Aphids multiply 
fastest when corn is in pre-tassel or late-whorl to brown silk stage. Since most of our 
com is now, or soon will be, beyond this susceptible stage, and since aphid populations 
are low, we do not anticipate a generally severe problem. Continue to examine late corn 
particularly in the drier areas of Illinois. Aphid populations may still increase and 
damage these fields. Treatment is warranted when corn is in the late-whorl to early 
tassel stage and when 50 percent or more of the plants have a light to moderate number o 
aphids. At the latest, treatment should be made prior to brown silks. 

Spray treatments by ground or air, with 1 pound of malathion or diazinon or 1/4 pound of 
methyl parathion per acre, are effective. Allow 5 days for malathion, 10 days for diazi 
and 12 days for methyl parathion between treatment and harvest for grain, ensilage, or' 
stover. Methyl parathion should be applied by experienced applicators only . If corn is 
in the late-whorl stage, seed producers may prefer to use 1 pound per acre of either 
diazinon or phorate (Thimet) as granules. To avoid potential hazards to detasselers, 
use phorate only on male-sterile corn. 

Second -generation European corn borer moth emergence is well under way in southern sec- 
tions, and eggs are being laid. Moth emergence is just beginning in the central section 
Pupation reached about 20 percent in the northern section. Now is the time to check 
late-maturing fields for egg masses or whorl feeding in the southern section. Wait abou 
a week in the central section and about 2 weeks in the northern section. Treat whorl - 
stage corn if 75 percent or more of the plants show recent whorl feeding. Apply 
carbaryl (Sevin) or diazinon as granules. Treat tasselled corn if the egg mass per plan 
averages one or more. Apply an insecticide after a few eggs have hatched. 

Commercial applicators may prefer to use parathion at 1/2 pound per acre. Sprays by air 

or with high -clearance ground equipment are effective on tasselled corn. Allow 10 days 

between treatment and harvest when using diazinon and 12 days for parathion. Carbaryl 
has no waiting period. 



■3- 



30YBEAN INSECTS 

grasshoppers continue to damage fields of soybeans and corn. They can also be found in 
fence rows, ditchbanks, and roadsides, from where they may move to soybeans or corn at 
any time. If grasshoppers are damaging soybeans or corn, they can be controlled with a 
spray of 3/4 pound of actual carbaryl (Sevin) or 1-1/2 pounds of actual toxaphene. 
\llow 21 days between treatment with toxaphene and the harvesting of soybeans for grain. 
)o not feed toxaphene -treated soybeans or corn as forage to dairy cattle or livestock 
fattening for slaughter. Carbaryl has no restrictions. For treatment of ditchbanks 
and roadsides, use one of the same insecticides listed above. It is wise to control 
grasshoppers in these nonagricultural areas before they have a chance to move into 
:rop lands. 

iOME OWNER INSECT PROBLEMS 

tystershell scale eggs will be hatching soon in the central section. The young crawlers 
set up housekeeping on shrubs like lilac and dogwood. They suck the juices from the 
slant and if abundant, they can seriously retard growth and even kill the plant. This 
Is the second generation of this scale and the build-up is often heavy. If you have had 
a history of problems in your yard, spray the shrubs thoroughly with malathion using 
2 teaspoons of the 50- to 57 -percent liquid concentrate per gallon of water. Target 
dates for spraying are right now in the southern sections , August 10 in the central 
section, and August 20 in the northern section. 

Sod webworm moths are increasing in numbers as emergence continues in the central section, 
rhere are still more to come. These buff -colored moths rest in shrubbery and tall grass 
luring the day and are seen flying in a zigzag pattern over the lawn near dusk. Second- 
generation moths are laying their eggs at this time. If you find large numbers of these 
noths in your yard, plan to treat your lawn with an insecticide about 2 weeks later. 
Jsually target dates for treatment are now in southern sections, early to mid-August in 
the central section, and mid- to late August in the northern sections. 

fhe larvae of the webworm are gray worms with brown spots and black heads. They are 
about an inch long when full grown and live for 3 to 4 weeks in the worm stage. The 
vorms live in silken-lined burrows in the thatch of the lawn, clipping off grass 
blades at the base. Brown spots appear in the lawn and large numbers of robins will 
nove in to feed on the larvae. By this time, it is usually too late for control. 

For control of webworms, apply a spray or granules of 2 pounds of actual carbaryl (Sevin), 
1 pound of actual diazinon, or 1-1/4 pounds of actual trichlorfon (Dylox) per 10,000 
square feet. Use about 25 gallons of water to distribute the insecticide over the 10,000 
square feet when spraying. Do not water the lawn for at least 3 days after treatment. If 
leavy rains occur within 3 days of application, a repeat treatment may be needed. 

rhere are a large number of mosquitoes in most areas of the state. To reduce the number 
Df mosquitoes in home yards, follow these steps: (1) Eliminate standing water in such 
Dlaces as eave troughs, old tires, tin cans, childrens' toys, storm sewers, etc., (2) Apply 
a water-base spray containing 1-percent malathion (2 ounces of 50- to 57-percent liquid 
:oncentrate per gallon of water) to shrubbery and tall grass. Repeat the treatment every 
reek or two if needed. (3) Keep the screens on doors and windows in good repair. 
'4) Hang plastic resin strips (2" x 10") containing 20-percent dichlorvos (DDW)--one strip 
Der 1,000 cubic feet of space, or about one per room. These strips will kill mosquitoes 
and flies for 4 to 6 weeks. As an added precaution, hang the strips where children cannot 
reach them and away from fish bowls and food counters. A 0.1 -percent pyre thrum space 
spray- -applied from a pressurized spray can- -can be used for quick knockdown in place of 



-4- 

the dichlorvos resin strips. Frequent treatments will be needed during problem periods. 
(5) When entering mosquito-infested areas, use a repellent. One of the most -effective 
mosquito repellents is DEET (diethyltoluamide) . (6) For quick knockdown at cookouts, out- 
door parties, or picnics, use either 0.1-percent pyrethrum or 0.5-percent dichlorvos 
(DDVP) as an oil- or water-base space spray. Spray the mist lightly beneath tables and 
chairs and into the air for a few feet around the area. Repeat the treatment as needed. 



WEEDS 



Johnsongrass grows actively with the current moist and warm weather. Now is a good time 
to treat. If you have Johnsongrass growing in small-grain stubble, in drowned- out bottom- 
lands, or in idle acres, here is a good control program: 

1. Qiop or clip the Johnsongrass a time or two. This is not essential, but when the tops 
are cut, food reserves are drawn from the roots and rhizomes, making chemical treat- 
ment more effective. 

2. Let the Johnsongrass regrow to about a foot high. 

5. Spray with Dowpon. Use 8 pounds of Dowpon commercial product in 30 to 40 gallons of 
water per acre; 5 pounds may be adequate, though not as effective as 8 pounds. Dowpon: 
contains a wetting agent, but additional nonionic surfactant or wetting agent may im- 
prove performance on grass leaves that are difficult to wet. 

4. Wait at least 3 days before disking or plowing. The delay gives Dowpon time to move 
from the leaves to rhizomes for more complete kill. Then disk or plow. Tillage 
provides further control. 

5. The area can be planted to corn or soybeans next spring. To control seedling Johnson- 
grass in corn, use a preemergence herbicide such as Eptam or Sutan. For soybeans, 
use Treflan, Plana\ r in, or Vernam. 

The above program is one of the best for Johnsongrass control. You can use a similar , 
program in the spring, but the program is not nearly as practical. You must delay corn 
and soybean planting at least 5 weeks after applying Dowpon to give the chemical time to 
decompose. 

Start your quackgrass control program this fall. Five pounds of AAtrex 80W applied at 
least 3 weeks before freezing usually gives excellent control. We still get many ques- 
tions on how to control quackgrass after corn is planted. You just can't get good con- 
trol then. 

So plan ahead with the fall or early spring applications. Dowpon and amitrole-T are 
other possibilities for quackgrass control. See Illinois Circular 892. 



DISEASES 



Phyllosticta yellow leaf blight has been found recently for the first time in Illinois 
in the northern tier of counties. This nav disease of corn has been reported in Wis- 
consin, Michigan, Missouri, Minnesota, Indiana, New York, and Pennsylvania. This disease 
has so far been found on the earparent in seed production fields, and is not likely to 
appear in farmers' fields. 



-5- 

Its symptoms are similar to those of southern com leaf blight. In its early stages, 
yellow leaf blight produces symptoms that resemble those of nitrogen deficiency, es- 
pecially on the lower leaves. Close examination, however, shows that the chlorosis 
is caused by a large number of individual elongated yellow spots. The spots, 1/4 to 
1/2 inch long, are elliptical to oval and have tan to cream-colored centers. You can 
expect the disease to move to the upper leaves and the leaves of more susceptible va- 
rieties and inbreds to die. Aerial application of Dithane M-45 has been recommended 
as a control by Wisconsin plant pathologists although its effectiveness has varied 
somewhat. 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Hosooe Randell, Don Kuhlman, and Stephen Sturgeon, 
University of Illinois College of Agriculture, Urb ana-Champaign, and Illinois Natural 
History Survey. 

WEEDS: E.L. Knake and M.D. MoGlamery, Department of Agronomy. 

DISEASES: E.E. Burns, Department of Plant Pathology . 

AG COMMUNICATIONS : Del Dahl. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



mj- 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



: ATE/COUNTY/LOCAL GROUPS/US. DEPARTMEMT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 1, April 3, 1970 
v 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and eommercial vegetables excepted) , along with sug- 
gested, abbreviated control measures. Each individual should check his own fields 
to determine local conditions. 

THE LIBRARY OF THE 



INSECTS 



FORAGE 



JUN 1 8 1970 

iiMlvFRjirY Ot- ILLINOIS 
U A T 1V U%ANA.CHAMPAIGr4 



Alfalfa weevil development is slow because of the cool weather. There are about 
the same number of eggs per square foot in southern Illinois alfalfa fields now as 
a year ago. Further north, in central Illinois, egg counts are higher than last 
year. If the alfalfa begins to grow before weevil hatch, alfalfa growers may be 
able to get by with only one spray application; also, the later the hatch, the 
larger the number of parasitic wasps to attack and kill the alfalfa weevil larvae. 

In 1969, the first applications of insecticides began the week of April 18 in 
southern Illinois. Unless temperatures moderate rapidly, this year will be like 
last year- -both in the timing of the insecticide applications and the intensity 
of the attack. Although some alfalfa fields required an insecticide application 
in 1969, many others needed no insecticides at all. The weather during the next 
few weeks will be very important in determining the importance of the alfalfa 
weevil to the 1970 alfalfa crop. 

Clover leaf weevil larvae, green worms with a white stripe down the back, resemble 
the alfalfa weevil larvae --except that the head of the alfalfa weevil is black and 
that of the clover leaf weevil is brown. Furthermore, the clover leaf weevil feeds 
at night and hides in the ground debris during the day, and the alfalfa weevil lar- 
vae are on the plants all day long. 

If red clover is covered with straw and other debris and growth is retarded, these 
clover leaf weevil larvae can cause severe damage during extended periods of cold 
weather. On the other hand, warm, humid weather promotes plant growth as well as 
a fungus disease that kills these pests. Clover can usually grow away from damage; 
but if growth is slow and leaf feeding is severe, a spray of 1 pound of malathion 
per acre (or mixtures of malathion or diazinon and methoxychlor) will reduce the 
insect population and allow the plants to grow. Malathion alone is most effective 
when the air temperature approaches 60° F. 



CORN INSECTS 



European corn borer winter survival is higher than usual. At this time of year, 
20 to 30 percent of the borers found in the old corn stalks are usually dead. This 



year in the southeastern, southern, and west -southwestern sections of Illinois, sur- 
vival is high and mortality is less than 10 percent. Preliminary surveys this week 
in western Illinois indicate a 15-percent mortality. 

CLARIFICATION OF SOIL INSECTICIDE USES 

Our suggestions for using soil insecticides in Illinois cornfields have been: 

1. Where rootworms are not a problem: As a minimum use a diazinon seed treatment. 
Otherwise apply 1.5 pounds of diazinon or 1 pound of Dasanit, Dyfonate, or 
phorate (Thimet) at planting time in a 7- inch band on the soil surface ahead 
of the press wheel. If you suspect that garden symphylans are present, use 
Dyfonate at planting time. 

2. In fields where rootworm problems are anticipated: Apply Dasanit, Dyfonate, 
or phorate (Thimet) as a 7-inch band on the soil surface ahead of the press 
wheel; or, treat the seed with diazinon and apply BUXten or carbofuran as a 
7-inch band ahead of the press wheel; or treat, the seed with diazinon and 
make a basal application of BUXten, Dasanit, or phorate in June. 

3. We suggest that present supplies of aldrin and heptachlor be used up by ap- 
plying them to fields of grass sods being plowed up for corn, to clover sods 
to be planted to corn, or to fields to be planted to corn, where white grubs 
are a problem. 

4. The reason for dropping aldrin and heptachlor from our general use soil -insecti- 
cide recommendations is based on low yield returns for treatments, the continual 
appearance of insect strains resistant to these chemicals, low wireworm popula- 
tions, and the continual environmental contamination of insecticides with a long 
residual life. 

In twelve fields where picker yields were compared in 1969, we had the following re- 
sults : 

Organophosphates--118.7 bushels per acre 

Only diazinon seed treatment --111. 9 bushels per acre 

Nothing- -109. 9 bushels per acre 

Chlorinated hydrocarbons- -106. 3 bushels per acre 

Seven of these fields had sufficient corn rootworm populations to affect yields, 
but five did not. Thus, we attribute these yield differences to the control of or 
the failure to control rootworms, seed beetles, seed maggots, garden symphylans, 
and perhaps other insects we failed to observe. Wireworms, cutworms, grape colaspis , 
white grubs, corn root aphids , and sod webworms were not present in these fields. 

Wireworms, grape colaspis, corn root aphids, and sod webworms have not been a general 
problem in Illinois for several years. Cutworms usually affect no more than 1 to 2 
percent of the total corn acreage in Illinois. 

These facts influenced our thinking in making our 1970 suggestions to Illinois farmers 
for soil-insect control practices in cornfields. For further information, see Circu- 
lar 899, Insect Control for Field Crops. It is available from your county Extension 
adviser. 



-3- 



HOMEOWNER INSECTS 

Garden soil insects (including wireworms, seed and root maggots, and white grubs) 
can be controlled by mixing in 4 ounces of 25-percent diazinon per 1,000 square 
feet of garden area. Do not use aldrin, heptachlor, phorate, or other insecti- 
cides that are labeled for corn soil insect control. 

Reports of cluster flies have been numerous this spring. These sluggish adult 
flies, slightly larger than the common house fly, moved into houses during the 
fall. They are now becoming active, moving out of wall partitions, and clustering 
in large numbers at windows in the attic or upstairs area. To control these flies, 
hang 20-percent dichlorvos (DDVP) resin strips in attics or other areas where they . 
are present --but not in kitchens, or other areas where food is present, nurseries, 
or rooms where infants, those who are ill, or elderly people are confined. 

One strip per 1,000 cubic feet will provide control for four to six weeks. A 
pressurized spray can containing 0.1-percent pyrethrin, used as a space spray, 
will give a good kill of the flies present, but will not provide residual pro- 
tection in the area. 

Spring cankerworms , dark-brown to dark-green measuring worms, will be feeding soon 
on trees like American elm and apple, as well as on other fruit and shade trees. 
They attack early, feeding on developing leaf buds and newly developing leaves. 
Sometimes they completely strip a tree of foliage, while other trees are only partly 
defoliated. When full-grown, the worms drop to the ground by means of silken threads 
that appear like streamers in the wind. By this time, it is usually too late for 
control. 

As a foliage spray, use either carbaryl (Sevin) with 2 pounds of 50-percent wet- 
table powder or lead arsenate with 4 pounds in 100 gallons of water. 



PLANT DISEASES 



MERCURY SEED TREATMENTS 

As you probably have heard by now, mercury seed treatments (Panogen, Ceresan, 
Ortho LM, and Chipcote- -the ones we have recommended) should no longer be applied 
to small grain seed, except to use up present supplies. We suggest the use of 
Vitavax, preferably with thiram or captan added. Any seed- treating establishment 
or farmer can treat up to 10,500 pounds of any small-grain seed under the current 
Vitavax label. By itself, Vitavax does a good job against external and internal 
smuts and some other seedling blighters, but is much less effective against other 
fungi that help reduce stands and yields. This is where the addition of captan 
or thiram will help give broad- spectrum control. Full clearance of these products 
is expected by mid-summer, in time for treating winter wheat seed. 



GENERAL INFORMATION 



Cautions : Be careful when filling sprayers near wells. Many accidents have oc- 
curred in the past. Keep the hose from the well out of the spray tank- -back si- 
phoning can occur. Be careful not to spill concentrates alongside the well. Do 
not drain sprayers by the well. Following these and other precautions may prevent 
problems this year. 



Farmers are now using some of the newer insecticides. These should be handled with 
respect. Wear rubber gloves when handling, never pour by holding a container above 
your head, and always pour granules into hoppers so that the wind will blow any 
dust away from you. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H .B . Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Cooley , 
College of Agriculture , University of Illinois at Urbana-Champaign , and the Illi- 
nois Natural History Survey. 

PLANT DISEASES: M.C. Shurtleff , Department of Plant Pathology . 

AG COMMUNICATIONS : Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



_//-?/ 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US. DEPARTMEMT OF AGRICULTURE COOPERATING 



OR IMMEDIATE RELEASE 



No. 2, April 10, 1970 



'his series of weekly bulletins provides a general look at the insect, weed, and plant 
lisease situation (fruit and commercial vegetables excepted) , along with, suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 



■ocal conditions, 



■OR AGE INSECTS 



INSECTS 



THE LIBRARY OF THE 

JUN 1 8 1970 

UNIVERSITY Of ILLINOIS 
*$ URBANA-CHAMPAIGN. 



Ifalfa weevil eggs began to hatch this past weekend with the warm weather, but cool 
eather could bring weevil development to a stand still. Populations of this pest will 
ary greatly from area to area, even from field to field. No statement can be made that 
ill apply to all fields in any one area. A few noticeably damaged fields may be pre- 
ent as far north as Kankakee on the east and Pittsfield on the west. However, the more- 
evere and general infestations, as expected, will be in the southern part of Illinois. 

.mall larvae can now be found in the southern part of the state, but feeding at present 
s minor and almost unnoticeable. Mien 25 percent of the tips show feeding, apply an 
nsecticide unless the crop is within 10 days of harvest. Treatments may be needed at 
he earliest in a week to 10 days in extreme southern sections, in about 10 days to 2 
eeks in the south central section, and in 2 to 4 weeks in the central section. 

he insecticide recommendations are: 



Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphosmethyl 
(Guthion) for good results. Use azinphosmethyl only once per cutting. Do not harvest 
for 15 days after treatment with methyl parathion, or 16 days for azinphosmethyl. Wear 
protective clothing. 

. Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per acre, 
(2) a mixture of 3/4 pound of malathion and 5/4 pound of methoxychlor per acre, (5) a 
mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre, 
or (4) 1-1/4 pounds of malathion per acre on days when air temperatures will be above 
60° F. for several hours after application. Do not harvest for 7 days after treatment 
with Imidan, methoxychlor, diazinon, or mixtures of them. There is no waiting period 
for malathion. Do not apply Imidan more than once per cutting. 

lover leaf weevils are green worms with a white stripe down the back . They resemble 
Ifalfa weevils. They often feed on red clover, however, and do feed at night- -hiding in 
ail debris during the day. Clover can usually grow away from damage; but if growth is 
low and leaf feeding is severe, a spray of 1 pound of malathion per acre (or mixtures of 
alathion or diazinon and methoxychlor) will reduce the insect population and allow the 
Lants to grow. Malathion alone is most effective when air temperatures are 60° F. or 
Dove. 



CORN INSECTS 

Corn seed beetles may again be a problem if germination is slow. This is when their attack 
can reduce stands , sometimes seriously. Usually, but not always, this is more of a problem 
with corn planted early. 

Soil applications of Dasanit, diazinon, Dyfonate, and phorate (Thimet) will control this 
beetle. You can no longer depend on aldrin and heptachlor soil treatments to do the job. 
Diazinon seed treatments alone will also control seed beetles. About 10 percent of the 
people who used this method in 1969 complained about the effect on seeding rates. Adding 
a dust to the seed may pose a reduced seeding-rate problem. To avoid this, when using 
seed treatments : 

1. Treat seed in a separate container, so excess dust will not be in the planter box. 

2. Empty planter boxes frequently, to prevent powder from accumulating in the bottom. On 
plateless planters, clean out the trap often. Clean up plastic plates and other plante 
box mechanisms at the end of the day. 

5. Do not overdose. 

4. Check frequently for wear or chemical caking on the planter plates, particularly on 
plastic plates. Some plastic plates also become "gummy" from chemical reaction. 

5. In some instances, using plates with a size-larger cell may be helpful. Adding some 
extra graphite may also help maintain the seeding rate. 

When to use diazinon seed treater: 

1. Use it if you are using no soil insecticide at all, or when you are using aldrin, 
heptachlor, or BUXten. Furadan may or may not control the beetles. 

2. You do not need diazinon seed treater if you are applying Dasanit, diazinon, Dyfonate, 
or phorate (Thimet) as a soil insecticide . 

Soil Insecticides : Aldrin and heptachlor no longer satisfactorily controls the three corn 
rootworms, seed beetles, seed maggots, or garden centipedes (symphylans) ; but do control 
grape colaspis and wireworms with row or broadcast treatments . Aldrin and heptachlor also 
control cutworms and white grubs, if broadcast and disk-in prior to planting. 

Dasanit, Dyfonate, and phorate (Thimet) control the rootworms, seed beetles, and seed mag- 
gots, and provide some protection against garden centipedes. Diazinon will do the same, 
except that it will not control the corn rootworms. Dyfonate will provide the best pro- 
tection against garden centipedes. All four will give some protection against wireworms 
and corn root aphids, very little control of cutworms, and no control of white grubs. 

Our Illinois recommendations are printed in Circular 899, Insect Control for Field Crops. 



Cautions : Do not apply the newer insecticides in the planter shoe next to the seed, as 
you have done with aldrin or heptachlor. With some, the germination of the seed may be 
affected. Apply them in a 7-inch band just ahead of the press wheel. 



WEOWNER INSECTS 



uigus gnats will soon appear, attracting the attention of many people. These small, gnat- 
ke flies develop in wet, decaying organic matter. They get into homes and are nuisances, 
iside the home, a spray of 0.1-percent pyrethrins applied from a pressurized can will give 
mporary relief. 



WEEDS 



1W CLEARANCE 

aisanto has announced new clearances for alachlor (Lasso) . Lasso is now cleared for tank 
_xing with atrazine (AAtrex) for corn and with linuron (Lorox) for soybeans. The rate 
.earance for clay soils and soils with over 3-percent organic matter has also been in- 
leased to allow the useage of 3- and 4-pound rates per acre. Most of the material avail- 
>le in 1970 will not have this information on the label . 

JACKGRASS 

: you are in quackgrass country (northern Illinois) , it is still not too late to think 
)out a control program in corn. Atrazine (AAtrex) is the key to quackgrass control. The 
ite is 5 pounds per acre of the 80 -percent wettable powder. This can be applied as a 
.ngle application preplant, or as a split application of 2-1/2 pounds per acre in the 
)ring and 2-1/2 pounds per acre at planting time. 

ZGETABLE GARDENS 

Cultivation and mechanical removal . THIS METHOD IS THE MOST -USED AND SAFEST ONE FOR 
THE HOME GARDEN. It must be repeated several times through the growing season of a 
crop. Vacations or absence from the garden is a negative factor for this method. 

Mulching or smothering weeds . This prevents light from reaching the weed seedlings . 
Several opaque materials used are- -Kraft papers, black polyethylene, ground corn cobs, 
week- seed- free straw, other fresh vegetation, and composted vegetation. 

, Use of herbicides . This is not practical in small vegetable gardens with several crop 
species. Different vegetables and weeds vary in their tolerance to herbicides. Thus, 
ideally , several herbicides should be used. Certain desirable herbicides for certain 
vegetables remain in the soil longer than one growing season, and may kill or injure 
different vegetables the following year. Applications must be carefully controlled 
when a herbicide is used on a small area. The tendency is to apply additional amounts 
if the quantity measured-out "looks" as though it is not enough. 

my home vegetable gardens are not large enough to make buying several herbicides worth- 
rile. But Dacthal, Amiben, or Treflan can be used by the home or small commercial gardener 
10 doesn't want to hand weed but wants to use a herbicide. Dacthal, Amiben, or Treflan are 
)t the most desirable herbicides for a large planting of an individual species. The most- 
;sirable ones for individual vegetable species are listed in Circular 907, Herbicide Guide 
>r> Commercial Vegetable Growers. 

icthal can be used on snap or garden beans, broccoli, brussel sprouts, cabbage, cantaloupe, 
lulif lower, collards, cucumbers, eggplant, lettuce, mustard greens, onions, peppers, potatoes, 
juash, strawberries, sweet potatoes, tomatoes, turnips, and watermelons. Dacthal must be 
)plied to weed-free soil, because it is a weed-seed germination inhibitor. Best results 



are obtained if it rains if you irrigate 2 to 5 days after application. The best applica 
tion time varies with species. Follow label suggestions on the Dacthal container for time 
of application. 

Amiben, (also sold as Begiben) is a herbicide used in soybean culture. It can also be 
used on the following vegetable species: dry and lima beans, peppers, pumpkins and squash 
sweet potatoes, and tomatoes. 

Treflan is also used in soybean culture, and can be used on the following vegetable specie 
snap, dry and lima beans, broccoli, brussel sprouts, cabbage, cauliflower, carrots, kale, 
mustard greens, okra, peas, peppers, tomatoes, and turnip greens. Treflan must be worked 
into the soil before transplanting or seeding. To insure uniform incorporation, use a 
rototiller or double-disk the soil at right angles. For more information, contact your 
local Extension adviser or the UI Department of Horticulture, 124 Mumford Hall, Urbana 618 
Ask for VG-4, Weed Control in the Vegetable Garden. 



MACHINERY 



GRANULAR INSECTICIDES 

Now is the time to get granular pesticide applicators ready. If you plan to use insecticiis 
such as BUXten, Dasanit, diazinon, Dyfonate, Furadan, or phorate (Thimet) , have the 7-inch 
spreading devices or banders positioned ahead of the press wheel. Your equipment dealer ■ 
should have these available for your planter. 

To calibrate a granular applicator, get the recommended setting for your unit from the 1 
dealer. Use the setting as a start, then calibrate the units in the field by collecting a], 
weighing the granules dispensed over a known acreage. Remember, the application rate will 
vary with the ground speed, moisture content of the granules, and many other factors. 

Don't expect the setting to be the same for each applicator unit. To check the application 
rate of each unit, place a strip of masking tap vertically on the inside of the applicator! 
hopper, then fill the hopper a pound at a time. After each pound is added, shake the hopp< 
to settle the material and mark the tape at the level of the chemical. Then, the amount o. 
material used can be easily checked by simply reading the level of the chemical before and 
after planting a known acreage. 

SEED TREATMENT 

Preliminary tests for potential seeding problems with diazinon corn-seed treater indicate 
that diazinon mixed with the seed before being placed in the planter hopper gives the 
fewest problems. In some instances, attempts to mix the treatment and the seed in the 
hopper have resulted in extreme variations in the amount of treatment on the seeds and 
excess dust in the bottom of the planter box. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Cooley , College of 
Agriculture , University of Illinois at Urbana-Champaign , and the Illinois Natural History 
Survey . 

MACHINERY: J.C. Siemens, Department of Agricultural Engineering. 



-D- 

WEEDS: M.D. McGlamery , Department of Agronomy , H.J. Hopen , Department of Horticulture . 
AG COMMUNICATIONS: Del Dahl. 

The information for this report vas gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBAN A-CH AMP AIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



^ 



0* 



^ 



-OR IMMEDIATE RELEASE 



ytPtfP' No. 3, April 17, 1970 



Fhis series of weekly bulletins provides a general look at the insect, weed, and plant 
lisease situation (fruit and aommeroial vegetables excepted) , along with, suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



?0RAGE INSECTS 

Ufalfa weevil development is slightly behind last year. Generally, alfalfa growth is 
;ood, and damage from alfalfa weevil larvae should not be much different than last year, 
fhese green larvae have a light stripe down the back and shiny black head. 

(n southern Illinois this week, they were still very small and hardly noticeable at a 
luick glance. Some feeding was observed, but only by careful examination of the new 
shoots. Applications of insecticides, where needed, probably should not be made until 
late next week at the earliest. 



tn south-central and central Illinois, an occasional larva can be found. The adults, 
low present in moderate numbers, are laying their eggs. With normal temperatures, treat- 
ments with insecticides will not be needed for at least 10 days to two weeks in south- 
:entral Illinois, and not for 3 weeks in central Illinois. 

vhen there is feeding on 25 percent or more of the terminals and the field is more than 
;wo weeks from harvest, an insecticide application is justified. 

ihe insecticide recommendations are: 

Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphosmethyl 

(Guthion) . Use azinphosmethyl only once per cutting. Do not harvest for 15 days after 

treatment with methyl parathion, or 16 days for azinphosmethyl. Wear protective cloth- 
ing. 

Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per acre, 
(2) a mixture of 5/4 pound of malathion and 3/4 pound of methoxychlor per acre, (3) a 
mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor per 
acre, or (4) 1-1/4 pounds of malathion per acre on days when air temperatures will be 
above 60° F. for several hours after application. Do not harvest for 7 days after 
treatment with Imidan, methoxychlor, diazinon, or mixtures of them. There is no wait- 
ing period for malathion. Do not apply Imidan more than once per cutting. 

Tover leaf weevil larvae are very numerous in some red clover fields in southern Illinois, 
"he clover is growing, however, and damage is still minor, although it may become more 
ipparent soon. 



A disease of clover leaf weevil in epidemic form can eliminate this pest as a problem, whe 
the weather is warm and "muggy." The first indication of this disease is when the normall 
green larvae appear yellow, then brown. The dead and dying larvae cling to the stems and 
leaves . 

If the weevils are dying, no insecticide is needed. If severe feeding is taking place, a 
spray of 1 pound of malathion per acre (or mixtures of malathion or diazinon and methoxych 
will reduce the insect population and allow the plants to grow. Malathion alone is most 
effective when the air temperature is 60° F. or above. 

HOMEOWNER INSECTS 

Now that spring yard work has begun, many questions are coming in about insect pests on 
ornamental plants. Euonymus scales , common on several shrubs like winter creeper, and 
euonymus evergreen ground cover may be confused with insect eggs . Saw dust castings from 
borers in the trunks of trees and shrubs can be found on the bark or accumulating at the 
base of the trunk. Although nothing can be done to control these pests now, a spray of 
malathion after the eggs of these scales hatch will be helpful --about early June in the 
central section of the state. The tunnels of the borers can be probed with a wire to kill 
the borers, or dimethoate sprays can be used later to prevent reinfestation. But right 
now is the time to pick last year's bagworms from the evergreens or other trees and burn 
them. About half of these bags will be full of eggs that will hatch in 4 to 8 weeks, then 
the small worms will begin to devour the needles. The more eggs you destroy now by pulling 
off the bags, the easier it will be to control the bagworms later. 

As you rake the old leaves around shrubs and the foundation of the house, you may find 
adult elm- leaf beetles and lady beetles . The elm-leaf beetle has a brownish-black body 
with yellow stripes on the wings. The yellow elm-leaf beetle larvae will appear later on 
Chinese elms. They skeletonize these leaves. No control of the wintering adults is needec 
Lady beetles are yellow, orange, or red insects, hemispherical in shape, with black spots.: 
They are beneficial, since they eat other insects. 

Clover mites appeared in great numbers this week. They have spent the winter under the 
siding of the house and in other protected areas. These minute brown or orange mites are 
present by the thousands on the sides of some houses, and often appear in huge numbers 
inside the windowsills. Use a vacuum sweeper to collect them inside the house or spray 
with a pressurized spray can containing 0.1 -percent pyrethrin or 0.5 -percent dichlorvos 
(DDVP) . Spray on the outside of the house and along the foundation with 1 -ounce of dicofol 
(Kelthane 18.5 W) or 4 ounces of chlorobenzilate per 3 gallons of water. Later this spring 
remove the grass and weeds next to the foundation for a strip 18 inches wide and plant this 
in flowers. Very few clover mites will cross this 18-inch barrier in the fall. 

Winged ants , often confused with termites, are now appearing in large swarms. Under Illi- 
nois conditions, if the body of the insect is yellow, red, or brown, it is almost certain 
to be an ant. If the winged insect is black, it could be a swarming termite. If the wings 
have many veins and there is no waist in the middle of the body, it is usually a termite. 

For identification contact your county Extension adviser, a local pest-control operator, 
or send the insect to 280 Natural Resources Building, Urbana, Illinois 61801, and we will 
identify it. 



-3- 

WEEDS 
2,4,5-T REGISTRATION 

The registration of liquid formulations of 2,4,5-T for use around the home and on lakes, 
ponds, ditches, and banks has been suspended. Nonliquid formulations for use around the 
home and on all food crops intended for human consumption may also be cancelled. The 
registered use of 2,4,5-T for controlling weeds and brush in ranges, pastures, forests, 
or on rights-of-ways and other nonagricultural uses are not affected at this time. More 
details are expected later. 

ORGANIC-MATTER CONTENT AND HERBICIDE RATES 

Herbicide rates are often varied by the texture and organic-matter content of the soil. 
Some of the herbicides most affected by the amount of organic matter are atrazine (AAtrex) , 
simazine (Princep) , linuron (Lorox) , trifluralin (Tref Ian) , and nitralin (Planavin) --as 
well as combination products such as linuron/propachlor (Londax) and propachlor/atrazine 
(Ramrod/atrazine) . 

You can estimate the organic -matter content by using the Color Chart for Estimating 
Organic-Matter in Mineral Soils in Illinois (AG-1941) . This information is also available 
from some soil test reports. The "1970 Weed Control Guide" section of the 1970 Illinois 
Agronomy Handbook has suggested rates for some herbicides, and can be used as a guideline. 
Tank-mix combinations present special problems because the different ingredients may be 
affected differently by the organic-matter content. 

Herbicides such as linuron (Lorox) and nitralin (Planavin) are not recommended for soils 
above 3- to 4-percent in organic -matter content. Other herbicides like propachlor (Ramrod) 
do not perform as well on soils of low- organic matter content as on those whose organic- 
matter content is medium to high. 

Organic -matter content is only one of the factors to consider in choosing a herbicide. Also 
consider the weeds to be controlled, and consult the 1970 Weed Control Guide. 

PRE PLANT APPLICATIONS 

AAtrex can be incorporated into the soil, but doesn't have to be. Applications can be made 
3 weeks before planting; usually, the closer to planting time the better. 

Apply Sutan just before planting and incorporate it right away. A spray boom just in front 
of the disk works well. Cross-disking is not essential. 

Be sure to apply Sutan accurately, uniformly --whether it is used alone or in combination 

with atrazine. This is especially true when liquid fertilizer equipment is used. Although 

not considered as a serious or extensive problem, we have had a few past cases of corn 
injury caused by overdosing and overlapping. 

Sutan plus atrazine has given good control of both grass and broadleaf weeds. Follow the 
same procedures and precautions as with Sutan alone. 

Lasso is now cleared for preplant incorporation for corn or soybeans, within 7 days before 
planting. The time of incorporation for Lasso is not critical. Present research suggests 
that preplant -incorporated applications of Lasso may be beneficial for controlling nutsedge. 
But for the control of annual grasses like panicum and foxtail, surface applications are 
probably best. 



The Treflan label now gives up to 4 hours for incorporation. Be sure you get Treflan on 
the right fields --only on those to be planted to soybeans, not corn. Incorporate Treflan 
twice- -once soon after application to reduce surface loss and again just before planting, 
to give final seedbed preparation, control of broadleaved weeds, and a more-uniform dis- 
tribution. 

If you want to use CIPC for added smartweed control, don't mix and incorporate it with 
Treflan. Apply CIPC to the soil surface at, or soon after, planting. Use 2 to 3 pounds 
per acre of active CIPC on a broadcast basis, either as liquid or granules. Apply pro- 
portionately less in a band. 

NEW CLEARANCES 

Lasso plus atrazine tank mix has been approved for corn. When used for preplant applica- 
tion, incorporate it like you would Lasso alone. There will probably be greater interest 
in surface applications at planting, since these provide broad -spectrum control of annual 
grasses and broadleaves. Use about 1-1/2 quarts Lasso plus 1-1/2 pounds atrazine 80W 
(broadcast basis) on light-colored silt loams with less than 3-percent organic matter. 
Use about 2 quarts Lasso and 2 pounds of atrazine 80W per acre for the darker, clay soils 
with over 3 -percent organic matter. 

Where Ramrod plus atrazine has performed well, growers should not be in too big a rush to 
switch to Lasso-atrazine, especially on the darker soils. However, the Lasso-atrazine 
combination would be less irritating to handle and better adapted to the light -colored, 
silt loam soils than Ramrod/ atrazine. Because Lasso is available as a liquid, the amount 
of water required per acre may be less than with the Ramrod- atrazine wettable powder. 

Lasso plus Lorox is also cleared as a tank mix for soybeans . This combination has per- 
formed well in research trials, especially on the light-colored silt loams. Adjust rates 
on the basis of the organic -matter content. The Lasso-Lorox combination should be applied 
only to the surface and not incorporated. 

AQUATIC WEEDS 

It is not too early to consider a program of aquatic plant control. Frequently, people 
wait until this problem is serious then wonder what happened. Actually, the problem has 
been developing and growing slowly since mid-April or earlier. When the warm weather 
comes, the water warms up rather quickly. Soon after, the weed infestation becomes severe. 

Consider what has happened during the past few years . Take time to check the body of water 
frequently, to see if some aquatic plant is growing. If it is, identify the problem and 
obtain the necessary aquatic herbicide so you will be ready when necessary. If a particular 
body of water was weedy last year, it is reasonable to expect that it will be again this 
year. 

HOMEOWNER PROBLEMS 

Now is the time to apply herbicides for crabgrass control in the lawn. Many excellent 
chemicals have been put on the market recently for preemergence control of crabgrass and 
certain other annual grasses. These materials may also control certain broadleaved weeds. 



Dae thai , Balan, Betasan, Bandane, Azak, Tupersan, and several other materials have given 
consistently good results in crabgrass control. All of these chemicals should be used 
as directed on the container. Most of the preemergence chemicals are in dry form, and 
nay be applied with a lawn seeder. Be sure that the spreader doesn't overlap, or that 
you don't apply too much material in any other way. Calibrate the spreader before using 
it. An over -application of the chemical can damage the grass. 

VEGETABLE GARDENS 

Last week, we said amiben was also sold as "Begiben" for use in vegetable gardens. It 
should have been "Vegiben." 



MACHINERY 



SEED TREATMENT 

Laboratory tests on the effects of the diazinon corn-seed treatment show that the effect 
on the cell fill is slight. Actually, this treatment increased cell fill about 3 per- 
cent, compared with that obtained using seed corn alone. A decreased in this percentage 
came about only when the diazinon was not well mixed with the seed and when excessive 
accumulation occurred in the bottom of the hopper. Therefore, it is important to treat 
the seed in a separate container and to use the treatment at the recommended rate. 

The 5-percent increase in cell fill from diazinon is close to that from graphite. Other 
factors such as variations in ground speed, change in cell fill as the hopper empties, 
and many others will affect cell fill just as much. When properly used, the effects of 
the diazinon seed treatment on the planting rate should be of little concern. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman , and Tim Cooley , College of 
Agriculture, University of Illinois at Urbana-Champaign , and the Illinois Natural History 
Survey . 

WEEDS: Ellery Knake and M.D. McGlamery , Department of Agronomy, J.D. Butler and H.J. Hopen , 
Department of Horticulture, R.C. Hiltibran, Illinois Natural History Survey. 

MACHINERY : J.C. Siemens, Department of Agricultural Engineering . 

AG COMMUNICATIONS : Del Dahl. 

The information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 



Ih 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA -CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 4, April 24, 1970 



This series of weekly bulletins provides a general look at the insect, weed, and plant 

disease situation (fruit and commercial vegetables excepted) , along with suggested 

abbreviated control measures. Each individual should check his own fields to determine 

local conditions. 

THE LIBRARY OF THE 



INSECTS 



JUN 1 8 1970 



FORAGE INSECTS 

UNIVfeRSIIY Ot= ILLINOIS 
AT UBBANA-GHAMPAIGN 

Alfalfa weevil populations are still low and the alfalfa seems to be growing. Because 
of the lower number of weevils and good plant growth, perhaps no insecticide applica- 
tions will be needed in many fields. Each field should be examined frequently, however. 

In southern Illinois, south of Harrisburg, small- to medium-sized larvae were present 
this week. Some adults are still laying eggs. It is now time to examine fields care- 
fully and decide whether you need an insecticide for weevil control. Continue this 
alert for at least two more weeks. 

In south-central Illinois, some larvae are present. Adult weevils are easy to find, 
but feeding is hardly noticeable. Treatment, if necessary, will probablynot be needed 
for one to two weeks, so begin to check fields this coming week. 

In central Illinois, occasional larvae can be found, but adults are much more common. 
Weevil feeding is not yet noticeable. Treatment, if needed, will not be for two to 
three weeks . 

When there is feeding on 25 percent or more of the terminals and the field is more than 
two weeks from harvest, an insecticide application may be justified. 

The insecticide recommendations are : 

1. Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) . Use azinphosmethyl only once per cutting. Do not harvest for 
15 days after treatment with methyl parathion, or 16 days for azinphosmethyl. Wear 
protective clothing. 

2. Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per acre, 

(2) a mixture of 3/4 pound of malathion and 3/4 pound of methoxychlor per acre, 

(3) a mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor 
per acre, or (4) 1-1/4 pounds of malathion per acre on days when air temperatures 
will be above 60° F. for several hours after application. Do not harvest for 

days after treatment with Imidan, methoxychlor, diazinon, or mixtures of them. There 
is no waiting period for malathion. Do not apply Imidan more than once per cutting. 



-2- 

SMALL GRAINS 

Armyworm moths are now flying. They will be depositing eggs on vigorously growing stands 
of grasses and grains, and will concentrate their egg-laying in spots within fields 
where the grain or grass is the most luxuriant. Examine such areas for the first indi- 
cations of armyworms. No serious infestations are expected for some time. 

CORN 

Soil insecticide . Several have asked us to rate the corn rootworm insecticides. Before 
making our 1970 recommendations last fall, we checked 1969 results for percent of worm 
kill, root damage, pounds of pressure required to pull the plants from the soil, and 
yields. Since we were not able to differentiate on the basis of performance, we listed 
the materials alphabetically. If seed beetles are present, use a diazinon seed treater 
when you plan to use basal treatments, or planting time treatments of BUXtenor furadan. 
Seed treatment is not needed if you use dasanit, dyfonate, or phorate (Thimet) at 
planting time. 

We further recommend the use of dasanit, diazinon, dyfonate, or phorate in fields where 
there are no rootworms. Do not expect these insecticides to control black cutworms or 
white grubs. They will give some control of wireworms and other soil- inhabiting insect 
pests. 

Nothing we have today will provide the overall insect control that aldrin and heptachlor 
did a decade ago; unfortunately, insect resistance now prevents these two materials from 
providing that same degree of control today. 

Armyworms may defoliate corn planted the "no-till" way. Sometimes this damage can be 
serious. The armyworm moths may be laying eggs in these fields now, and this egg- laying 
may continue for a few weeks. The worms that hatch during the next two to six weeks 
will be hungry. They will devour the young com plants in their search for food. 

Applications of 1 pound of malathion or trichlorfon (Dylox) or 1-1/2 pounds carbaryl 
(Sevin) or toxaphene per acre will effectively control these pests. Toxaphene will 
probably give the longest protection- -a week to ten days --against newly hatching worms. 

Remember, toxaphene is extremely toxic to fish, but it is probably the safest insec- 
ticide for use around bees. Carbaryl is extremely toxic to bees, but it is not too 
toxic to fish. 

HOMEOWNER 

You'll hear the singing of the periodical cicada or seventeen-year locust this spring 
and summer, in the eastern part of the state and in the southern sixteen counties. 
They may also be heard in Morgan, Tazewell, Logan, Knox, and Dewitt counties in the 
central section, and in Kane and Lee counties in the northern section. This pest is 
due to appear in May in southern counties --June in the central and northern counties. 
Of the thirty different broods of cicadas in the United States, at least ten are pres- 
ent in Illinois. This particular one, Brood X, was severe in 1955 when the adults 
laid their eggs. These adults prefer oak, hickory, apple, peach, and pear trees as 
well as grapevines for laying their eggs. Damage occurs when the female cicadas make 
slits in branches and twigs and deposit eggs. The small twigs and branches turn brown, 
die, and sometimes break off. The young nymphs that hatch crawl into the soil for 
another seventeen years, and remain in the ground sucking the sap from tree roots. 



Often, a wooded area infested in. 1953 with cicadas, has since been cleared. The cicadas 
will still emerge and cling to any vine, plant, or other upright object. When they 
emerge as adults, they will fly about in search of trees in which to deposit their eggs. 

We are anxious to update our records on the distribution of this brood of cicadas in 
Illinois, in order to make more-accurate predictions for 1987. Please send us spec- 
imens of cicadas that you encounter, noting the date and location (nearest town). 
Please mail the specimens to Dr. Lewis J. Stannard, 285 Natural Resources Building, 
Urbana, Illinois 61801. 

Protect young trees and shrubs by enclosing them in cheesecloth or mosquito netting. 
Carbaryl (Sevin) is effective as a spray. Use 2 pounds of the 50-percent wettable 
powder per 100 gallons of water. For smaller amounts, use 2 tablespoons per gallon 
of water. Apply the treatment when egg- laying begins, and repeat it 7 to 10 days 
later. Do not apply carbaryl to apple trees within 2.1 days after full bloom, because 
it may cause a thinning of the fruit. Do not apply to Boston Ivy. Repeated treatments 
with carbaryl may produce a buildup of mites, which will cause a russetting of the 
leaves. Adding 2 teaspoons of 57-percent malathion liquid concentrate per gallon of 
water to the carbaryl spray mixture will control these mites. 

Brown recluse spiders . Much attention has been 
given the brown recluse spider during the past few 
years. Since detection in Illinois during 1957, 
Dr. J.D. Unzicker, Taxonomist of the Illinois Natu- 
ral History Survey, has identified brown recluse 
spiders from 45 of the 102 counties in Illinois 
(see map) . 



The body of this spider is about 
1/2 inch long, the leg span 1 to 
1-1/2 inches. The color may vary 
from light fawn to almost dark 
brown ; with a distinct, fiddle- 
shaped, dark marking behind the 
head (see picture) . 

This spider is poisonous , and is 

now considered to be of public 

health importance. It bites only 

when disturbed. The brown recluse 

spider has a habit of living in dark, sheltered 

areas (such as attics), in stored goods, basements, 

crawl. spaces,, and barns. Unlike other web-spinning 

species, it spins very small or irregular webs. 





During the past year, we have received reports of 
bites that produced necrotic lesions that were 
painful and slow to heal. These have been attrib- 
uted to the brown recluse spider. Consult your 
physician about any such bite. We are trying to 
catalogue the distribution of this spider and 
others , and we will identify all spiders sent to the 
Natural Histoiy Survey in Urbana. Please send such 

specimens to Dr. John Unzicker, Room 93, Natural Resources Building, Illinois Natural 
History Survey, Urbana, Illinois 61801. Include your name, address, and where the 



April 1, 1970 , places where the 
brown recluse spider has been 
found in Illinois . 



-4- 



spider was found. When spider bites occur, the spider responsible should be captured 
if possible and sent to Dr. Unzicker for identification. 



WEEDS 



FORAGE CROPS 

Musk thistle is a biennial one that is now increasing in many areas of Illinois. April 
is the ideal time to control musk thistle, while the weed is still in the rosette stage 
and before the seed stalk forms. Usually, control is best when the plant is growing 
actively and temperatures are above 75° F. 

For spot treatment, add 1 quart of 2,4-D ester (4 pounds per gallon) and 1 cup of 
household detergent per 25 gallons of water. Spray until moist. For larger infesta- 
tions, use 1 to 1-1/2 quarts of 2,4-D ester in 20 or more gallons of water per acre. 

SMALL GRAINS 

Check small grains now to determine the need for chemical weed control. Used early, 
2,4-D will control broadleaved weeds such as wild mustard. 

If there is a legume underseeding , apply 1/2 quart per acre of 2,4-D amine (4 pounds 
per gallon of the formulation) . Never use 2,4-D ester with a legume underseeding 
unless you want to control wild garlic or wild onion, and then expect some kill of 
the legume. 

To control wild garlic and wild onion, use 1/2 quart per acre of 2,4-D ester . This 
will not completely control the weeds, but will reduce aerial bulblet formation and 
lessen the possibility of harvest- time dockage for "garlicky" wheat. 

Banvel (dicamba) can also be used for controlling smartweed or wild buckwheat in wheat 
and oats, but it is weak on wild mustard. Don't use Banvel on small grain sown with a 
legume underseeding . Use 1/4 quart per acre when spring grains are in the 3- to 5- leaf 
stage. Use on winter wheat before it reaches the joint stage. 

Treat small grains with 2,4-D after it has finished tillering in the spring but before 
it reaches the boot stage. That is about 4 to 12 inches in height. 

Read the label and follow all precautions. 

CORN AND SOYBEANS 

Incorporating the herbicide early is important, since most annual weed seeds germinate 
in the top 2 inches of soil. Most herbicides of moderate solubility move into the 
weed-seed zone with normal rainfall. The primary purpose of herbicide incorporation 
is to prevent surface loss of volatile herbicides and to move the herbicides of low 
solubility down into the soil. 

The tandem disk is the most-common tool used for herbicide incorporation. The disk 
should be operated at a depth of about 4 inches for best results. Using greater depths 
may cause excessive dilution of the herbicide. In general, field cultivators are not 
satisfactory for herbicide incorporation. The Treflan label does include the use of 
the mulch treader this year. 



Most volatile herbicides, such as Sutan and Vernam, should be incorporated immediately 
after application. The Treflan label allows the use of a 4-hour delay in incorporation, 
but the sooner the better. Lasso and AAtrex can be incorporated, but this is not neces- 
sary unless you are trying to control yelloiv nutsedge. 

Check. fields for weedy spots in corn. Giant ragweed is now germinating. Smartweed will 
soon start. Giant foxtail and pigweed will start germinating in about one to two weeks, 
depending on the temperature. 

If you find areas of high infestation, it may be worthwhile to consider broadcasting 
a herbicide. These areas are often along drainageways , turn-rows, headlands, and fence 
lines where it is most difficult to cultivate and use a rotary hoe. You can use a band 
application of herbicide, and cultivate the rest of the field. 

Yellow nutsedge (Cyperus esoulentus), often called nutgrass , has become a serious weed 
problem in many areas of Illinois. It is a sedge (with a triangular stem and three- 
ranked leaves), rather than a true grass (with a round stem and two-ranked leaves). It 
overwinters primarily as tubers (nutlets), which sprout in the spring and form rhizomes. 
A coronal node is formed on the rhizome about 1 to 1-1/2 inches below the soil surface. 
The crown area forms roots, shoots, and new rhizomes. New rhizomes form more plants at 
first; later in the season, they turn down and develop new tubers for overwintering. 

Thus, the crown area that develops below the soil surface is a critical area for yellow 
nutsedge control. The most-effective control program involves a combination of preplant 
tillage, an incorporated herbicide, and postplant tillage. 

Nutsedge is usually found in low- lying, wet areas. It generally emerges about corn- 
planting time, or by the time the plants emerge. 

The herbicides for nutsedge control in corn are alachlor (Lasso) , butylate (Sutan) , and 
atrazine (AAtrex). EPTC (Eptam) has provided adequate control, but corn tolerance has 
not been sufficient. The best treatments in research trials have been either butylate 
(4 pounds per acre), or alachlor (3 to 4 pounds per acre) --applied preplant incorporated 
and followed by an early postemergence treatment of atrazine (2 pounds per acre) plus 
nonphytotoxic oil (1 gallon per acre) . 

Nutsedge control in soybeans allows the farmer to locate the areas, use preplant tillage, 
and broadcast a herbicide just on these areas, because soybeans are planted later than 
corn. The two herbicides that have proven useful for nutsedge control in soybeans are 
alachlor (Lasso) and vernolate (Vernam) . Both of these should be used at the highest 
recommended rate, and should be incorporated. Incorporation can be combined with preplant 
tillage. 

Fall panicum is a grass weed that continues to germinate late in the season. Earlier 
planting and earlier "lay-by," combined with a greater dependence on chemicals and a 
reduction of tillage, have invited late-emerging weeds --especially in wide-row corn. 

Fall panicum is a problem throughout the state, but the greatest difficulty is in 
southern Illinois --because of wider rows, longer growing seasons, and a greater depend- 
ence on atrazine as a herbicide there. Fall panicum is a particular problem on zero- 
tillage corn. 

Simazine (Princep) is better than atrazine (AAtrex) on late-emerging grasses, such as 
fall panicum and crabgrass. Alachlor (Lasso) and butylate (Sutan) are two other her- 
bicides with enough persistence to control late-emerging grasses. Many people arc 



V 



combining atrazine or simazine with Lasso or Sutan to give broadleaf weed control. 
Remember, it is necessary to incorporate Sutan soon after application. 



MACHINERY 
SPRAYER CALIBRATION 

The importance of properly calibrating the application equipment used with agricul- 
tural chemicals cannot be overemphasized. For sprayers, the factors to be considered 
include nozzle type and size, operating pressure, ground speed, and the concentration 
of the chemical in the tank. It is important to check all of the variables involved. 
Copies of Circular 837, Calibrating and Maintaining Spray Equipment, are available and 
may be helpful. 

Several nozzle types are being used for applying herbicides. The regular, flat-fan 
nozzle is the most-popular one. It should be used at pressures between 15 and 30 p.s.i. 
never over 40 p.s.i. Nozzle spacing should be around 20 inches, with a boom height that 
provides about a 25-percent overlap. 

A nozzle manufactured for the specific purpose should be used for band spraying. 

Flooding, flat-spray nozzles are recommended for applying herbicides, especially where 
drift is hazardous because the particles are larger. 

Flooding nozzles should be mounted on about 40 -inch centers at such a height that the 
patterns of adjacent nozzles will overlap about 10 percent. If the boom can not be 
maintained at such a low height, the boom height can be increased to obtain double 
coverage. However, the spray will be more susceptible to drift and to distortion of 
the pattern because of the wind. 

Other nozzle types are also available. With proper selection, adjustment, and the 
like, these can be used to apply herbicides satisfactorily. 

All nozzles wear and require replacement. A brass nozzle tip should be replaced after 
it has been used to spray 100 acres. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , College 
of Agriculture, University of Illinois at U rb ana- Champaign , and the Illinois Natural 
History Survey and George McKibben, Dixon Springs Experiment Station. 

WEEDS: M.C. McGlamery , Department of Agronomy. 

MACHINERY: J.C. Siemens, Department of Agricultural Engineering. 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



SPECIAL NOTE TO RADIO AND TV STATIONS 

Our automatic telephone answering service will provide the following insect situation 
recordings, starting on Monday, April 27: 

Homeowner Insect Problems- -every Monday. 

Calling time- -9 a.m. Monday to 8 a.m. Tuesday. 
Dial (217) 333-2614 

Southern Illinois Insect Situation- -every Friday. 

Calling time- -9 a.m. Friday to 2 p.m. Friday. 
Dial (217) 333-2614 

Northern Illinois Insect Situation- -every Friday through Monday. 

Calling time- -3 p.m. Friday to 8 a.m. Monday 
Dial (217) 333-2614 

Each of these will be 2 minutes long. In case of questions or difficulty, call (217) 
333-4783. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
U R B AN A-CH AM P Al G N 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 

HATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING ^j Qf ' 

?0R IMMEDIATE RELEASE *%\^ eU** f 5 ' May 1 ' 197 ° 

This series of weekly bulletins provides a general look at the insect, weed, and plant 
lisease situation (fruit and commercial vegetables excepted) , along with suggested 
■Abbreviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



FORAGE 



Alfalfa weevil larvae are common in southern Illinois alfalfa fields, and feeding 
damage was quite evident this week. In south-central Illinois, the larvae were nu- 
merous and feeding was noticeable. In central Illinois (particularly in the west), 
larvae could be found easily only on south and west slopes, where feeding was evi- 
dent. However, alfalfa is growing rapidly and may outgrow the damage, except in 
fields where weevil populations are high. 

Equally important is the presence of a number of wasp parasites , especially in south 
and south-central Illinois. We cannot now establish the effect these parasites may 
have. They are emerging early, and will attack the weevil larvae now present and may 
eliminate them. If this is the peak of the parasitic wasp emergence, late-hatching 
larvae will escape and we will then see a flare-up of damage; but if this is just the 
beginning of parasitic wasp emergence, the alfalfa weevil will be in for a rough time. 

Do not apply insecticides unless they are needed. Examine each field regularly. When 
there is feeding on 25 percent or more of the terminals and the field is more than two 
weeks from harvest, an insecticide application may be justified. 

The insecticide recommendations are: 

1. Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) . Use azinphosmethyl only once per cutting. Do not harvest for 

15 days after treatment with methyl parathion, or 16 days for azinphosmethyl. Wear 
protective clothing. 

2. Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per acre, 

(2) a mixture of 5/4 pound of malathion and 5/4 pound of methoxychlor per acre, 

(3) a mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor 
per acre, or (4) 1-1/4 pounds of malathion per acre on days when air temperatures 
will be above 60° F. for several hours after application. Do not harvest for 7 
days after treatment with Imidan, methoxychlor, diazinon, or mixtures of them. There 
is no waiting period for malathion. Do not apply Imidan more than once per cutting. 



SMALL GRAINS 

Cereal leaf beetles are present in isolated areas of Illinois. The Illinois and U.S. 
Departments of Agriculture are cooperating in a suppression program. Malathion will 
be applied at 3 ounces per acre. It is an insecticide commonly used by homeowners on 
flowers, shrubs, and vegetables, and is no more toxic than aspirin if ingested. How- 
ever, this insecticide is extremely toxic to the beetle--also to mosquitoes and flies. 
Unfortunately, it is toxic to honey bees, too. Beekeepers have been warned by the State 
Apiary Inspector to cover hives or move them from areas to be sprayed. Spraying will 
begin on May 4 . 

Armyworm moth flight is increasing. Watch lodged spots in grain fields; also, grass 
fields with luxuriant growth. Moths concentrate their egg-laying in these spots, and 
the worms will appear there first. Worms should be noticeable in extreme southern 
Illinois within 2 to 5 weeks; in south-central and central Illinois, within 3 to 5 week: 

Applications of 1 to 1-1/4 pounds of malathion, 1 pound of trichlorfon (Dylox) , 1-1/2 
pounds of carbaryl (Sevin) , or toxaphene will control armyworms. Do not apply carbaryl 
to small grains after the boot stage. Do not feed forage or straw treated with toxapher 
or trichlorfon to dairy cattle, livestock being fattened for slaughter, or poultry. 
There is no waiting period between the application of toxaphene and grain harvest; a 
week is required when applying malathion, 21 days for trichlorfon. 

HOMEOWNER 

The seventeen-year locust or periodical cicada, Brood 

X, was a problem in 1953. This brood, the largest 

one in the eastern United States , is due to appear 

by May 20 in southern Illinois, and by about June 10 

in the northern 

part of the 

state. Emergence 

will reach a peak 

a few weeks 

later. 

In 1953, these 
periodical cica- 
das, were pre- 
sent in swarms 
in Vermilion, 
Edgar, Clark, 
Crawford , Law- 
rence, Wabash, Ed- 
wards , White , 
Williamson, Ran- 
dolph, Morgan, Knox, and Lee counties. They were 
present from a few specimens to swarms in other 
counties , as indicated on the map . 

Infestation during 1970 may well follow the 1953 
pattern. We are anxious to update our records on 

distribution of this brood of cicadas in Illinois, in order to make more-accurate pre- 
dictions for 1987. Please send us specimens of cicadas that you encounter, noting the 
date and location (nearest town) . Please mail such specimens to Dr. Lewis J. Stannard, 
285 Natural Resources Building, Urbana, Illinois 61801. 





ripider mite damage to Junipers has been reported. At first, the damaged foliage appears 
;o be finely mottled--then grayish, dry, and brown. To detect mites, strike a few 
tranches of the plant sharply with one hand while holding a white dish or piece of 
:aper under the branches with the other. If mites are present, they can be seen running 
ibout on the paper or dish when it is held in bright light. Apply dicofol (Kelthane 
L8. 5-percent emulsifiable) at 2 teaspoonsful per gallon of water. Spray to runoff. 

3yster shell scale young will soon begin hatching and crawling out from under the old 
scales on shrubs like lilac. These crawlers will feed on new growth by sucking the 
Dlant sap. Make two applications of malathion, 10 to 14 days apart, beginning about 
4ay 10 in southern Illinois, May 15 in the central section, and May 25 in the northern 
Dortion of the state. 

]rape flea beetles are feeding on the new foliage of grapes in many home gardens . Sprays 
Dr dusts containing carbaryl (Sevin) will control these tiny, greenish-blue beetles that 
jump when disturbed. 



WEEDS 
USE OF HERBICIDES IN GREENHOUSES 

Do not use a volatile herbicide inside greenhouses . When used under field growing con- 
ditions, most herbicides do not injure plants, because of volitalization from the soil 
surface. Under greenhouse conditions, soil surfaces are kept moist, which increases 
the volitalization of most herbicides, and the vapors are not swept away by air currents. 
%ny herbicides not considered volatile under field conditions can cause damage when 
contained in a greenhouse environment. The safest means of controlling weeds under 
greenhouse conditions is to remove them by hand, mulching, or using weed burners. 

If damage is noted from volatile chemicals, the soil should be removed as soon as pos- 
sible. (This is often not practical immediately.) Or, the soil should be drenched 
with 0.5 gram of activated charcoal per 5 pounds of soil (or 1 pound of activated 
charcoal per 1,000 pounds of soil). The activated charcoal may tie-up some soil nutri- 
ents. If nutrient deficiencies are noted, foliar feeding should be employed. 

Volatile herbicides (particularly the phenoxy types--2, 4-D/2, 4, 5-T/etc . --should be 
stored in structures completely separated from greenhouses and the like . A broken bag 
or leaking can will often cause phenoxy injury to sensitive flower or vegetable crops 
grown in close proximity to stored herbicides . 

HOME USE OF 2,4,5-T SUSPENDED 

The U.S. and Illinois Departments of Agriculture, Interior, and Health, Education, and 
Welfare have suspended the use of liquid 2,4,5-T, around the home, on lakes, ponds, or 
ditch banks. Cancellation for uses of nonliquid 2,4,5-T around the home and on all food 
crops intended for human consumption is expected. 

These actions are based on the opinion that using 2,4,5-T around the home and in water 
areas could constitute a hazard to human health. New information indicates that 2,4,5-T, 
as well as its contaminant, dioxins, may produce abnormal development in unborn animals. 
Nearly pure 2,4,5-T was reported to cause birth defects when injected experimental ly at 
high doses into pregnant mice, but not in rats. No data on humans are available. 



The use of 2,4,5-Ton range, pasture, and forests or on rights of way and other non- 
agricultural land is all right, but it should not be used near homes or recreation 
areas. A review is being made of registered uses, to make certain that these include 
adequate precautions against grazing in areas so that no contaminated meat or milk will 
result. The mam concern is the length of time between treatment by 2,4 5-T and'eraz- 
mg by animals. s 

While residues of 2, 4, 5-T in meat and milk are very rare, they are illegal and make 
contaminated products subject to seizure. There is no tolerance for 2,4 5-T on meat 
milk, or any other feed or food. 

The USDAwill issue guidelines for disposing of household products containing 2 4 5-T 
llns chemical is biologically decomposed in a moist environment. 

Research in November and December, 1969, indicates that 2,4, 5-T has produced a number 
of birth defects when fed or injected into certain strains of mice and rats, but the 
birth abnormalities could not be attributed with certaintv either to 2 4 5-T or to 
the impurities, dioxins, known to be present. Evidence of the extreme 'potency of the 
impurities as toxic agents was shown, and the 2, 4, 5-T now being marketed is of greater 
purity than that- which was tested. s 

Studies have been initiated to determine whether 2, 4, 5-T itself, its impurities, or a 
combination of both caused the earlier findings, and whether the 2, 4, 5-T now being 
marketed produces birth abnormalities in mice and rats. 

Taken separately the dioxin impurities and the 2, 4, 5-T, as it is now manufactured, both 
produced birth abnormalities in the experimental mice. Because absolutely pure 2 4 5-T 

Hnnf thTii lable f °^ T fi ng ' J* iS ° nly P° ssible t0 infe r from certain of the observa- 
tions that the pure 2,4 5-T probably would be teratogenic if tested. However, since 
pure Z,4,5-T is not marketed and could not be produced in commercial quantities this 
is not a practical issue for consideration. ' 

The measures being taken are designed to provide maximum protection to women during 
the childbeanng years by eliminating formulations of 2, 4, 5-T from use in household 
aquatic and recreational areas. Its use on food crops will be cancelled, and will be 
controlled on range and pastureland. Maximum surveillance of water supplies and 
marketed foods will be maintained, as a measure of the effectiveness of these controls 
Details will be announced shortly in the Federal Register. 

TANK-MIXING HINTS 

Many herbicides are being applied with liquid fertilizers. Problems of compatability 
sometimes arise when emulsifiable concentrates (EC's) are mixed with liquid fertilizers 
because the emulsifier is not salt-stable. Some manufacturers have special, pesticidal 
formulations for liquid-fertilizer application. Others specify the emulsion stability 
beadde^if needed. * COmpatabilit y a S ent ^ such as Compax or Spento 68) should 

If you can determine dilution factors, you can check compatability in quart jars before 
mixing a whole tank. First, determine the volume of spray per acre. With liquid 
fertilizers, this will depend on the analysis used and the rate desired. Next, determine 
the volume or weight of the pesticide to be applied per acre. Then, convert the number 
oi quarts or pounds of additives and gallons of spray carrier to an amount per pint of 
spray. Useful small measurement units are grams and milliliters. There are 454 grams 



per pound, and 946 milliliters per quart. Measuring spoons can be used for approxima- 
tion, if scales or pippetes are not available. One level teaspoon holds about 5 milli- 
liters or approximately 2 to 3 grams of wettable powder (WP) , although wettable powders 
(WP's) do vary in density. 

1 quart/25 gallon = 4.7 ml. /pint = 1 tsp./pint 

1 lb. (WP)/25 gallon =2.2 gram/pint = 1 tsp./pint 

To list the mix for adding 1 quart of EC and 1 pound of WP per 25 gallons, you would 
add 1 teaspoon of EC and 1 teaspoon of WP to 1 pint of the liquid fertilizer. 

Procedure : 

1. Place 1 pint of carrier into a quart jar. 

2. Add the proper amount of each pesticide. 

3. Close the jar and mix, by shaking or inverting it. 

4. Observe the mixture at once, and again after 30 minutes, to determine compatability 
and suspension stability. 

If the materials remain suspended or are easily resuspended, then uniform application 
will be possible with good agitation. If they separate, precipitate, or form "gunk," 
you need to rerun the test with the addition of a compatability agent, such as Compax 
(1/2 teaspoon per pint), to determine if this will solve the problem. 

Mixing procedures can make the difference between success and failure. Partially fill 
the tank before adding pesticides. Wettable powders should be pres lurried, emulsifiable 
concentrates preemulsified, with water (separately) before being added to liquid fer- 
tilizer. Add wettable powder to the tank before the emulsifiable concentrates. Always 
have the agitation system operating when the pesticides are added to the tank. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Cooley , College 
of Agriculture , University of Illinois at Urbana-Champaign , and the Illinois Natural 
History Survey. 

WEEDS: Ellery Knake and M.C. McG lamer y , Department of Agronomy, and Herb Hopen , Depart- 
ment of Horticulture . 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people , staff members , county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



-6- 

SPECIAL NOTE TO RADIO AND TV STATIONS 

Our automatic telephone answering service will provide the following insect situation 
recordings, starting on Monday, April 27: 

Homeowner Insect Problems --every Monday. 

Calling time --9 a.m. Monday to 8 a.m. Tuesday. 
Dd Dial (217) 333-2614 

Southern Illinois Insect Situation — every Friday. 

Calling time- -9 a.m. Friday to 2 p.m. Friday. 
Dial (217) 333-2614 

Northern Illinois Insect Situation — every Friday through Monday. 

Calling time- -3 p.m. Friday to 8 a.m. Monday. 
Dial (217) 333-2614 

Each of these will be 2 minutes long. In case of questions or difficulty, call (217) 
553-4783. 



TiA 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT, WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 

FOR IMMEDIATE RELEASE 



No. 6, May 8, 1970 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested 
abbreviated control measures. Each individual should check his own fields to determine 
local conditions. 

THE UI8RARY OF THE 



INSECTS 



JUN 18 1970 



FORAGE 

Alfalfa weevil larvae 
Pupation has already b 
southern third of the 
ments started late las 
may still be profitabl 
so rapidly that if the 
and treat the second g 



UNIVERSITY Qf IttiNOIS 
AT URBANA^HAMPAIQN 

are now very numerous in the southern third to half of Illinois, 
egun. Severe damage has occurred to some alfalfa fields in the 
state. Damage is common within most fields in that area. Treat- 
t week in fields where the weevils developed early. Treatment 
e in some fields, but damage and crop growth may have progressed 

field is within ten days of harvest, it might be best to cut 
rowth- -should this become necessary. 



In the central third of the state (latitude, St. Louis to Peoria), weevil development 
has progressed rapidly and damage is heavy. Now is the time to treat fields in that 
area. 

In the northern third of Illinois, only moderate damage is expected. Although alfalfa 
weevils are a severe problem in producing the first cutting of alfalfa in southern 
Illinois, they may be a second- cutting problem in the north. Therefore, watch the 
second growth of alfalfa in the northern section. 

Examine each field regularly. Do not apply insecticides unless they are needed. When 
there is feeding on 25 percent or more of the terminals and the field is more than two 
weeks from harvest, an insecticide application may be justified. 

The insecticide recommendations are: 

1. Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) . Use azinphosmethyl only once per cutting. Do not harvest for 

15 days after treatment with methyl parathion, or 16 days for azinphosmethyl. Wear 
protective clothing. 

2. Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per acre, 

(2) a mixture of 3/4 pound of malathion and 3/4 pound of methoxychlor per acre, 

(3) a mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor 
per acre, or (4) 1-1/4 pounds of malathion per acre on days when air temperatures 
will be above 60° F. for several hours after application. Do not harvest for ' 
days after treatment with Imidan, methoxychlor, diazinon, or mixtures of them. 
There is no waiting period for malathion. Do not apply Imidan more than once per 
cutting . 



:: 



Spittlebugs have been hatching for some time now. Control with insecticides has not 
been profitable for several years. However, if there is more than one spittlebug 
nymph per stem , treatment may be justified. Use 1/2 pound of methoxychlor per acre 
at least one week before harvest. 

CORN 

) 

Flea beetles will pounce on corn as soon as it emerges , particularly in southern 
Illinois. The winter may have been severe enough to kill some of them, but the snow 
cover may also have protected them. These small, black beetles jump when disturbed 
and are difficult to find on corn leaves, since they leave the corn before you get to 
the plant. They eat or strip the green from the plant leaf- -leaving tiny, white, 
elongated scratch marks on the leaves. Damaged plants will generally turn silvery, 
then brown. If enough plants are being killed to warrant the cost of insecticides, 
apply 3/4 pound carbaryl (Sevin) or 1-1/2 pounds of toxaphene per acre, as a hand 
spray over the row. 

Slender seed-corn beetles are active throughout the state. The phosphate insecticides 
[diazinon, dasanit, Dyfonate, and phorate (Thimet)] --applied as a 7-inch band ahead 
of the press wheel- -will control them. Diazinon seed-treater will also prevent seed 
and seedling damage. 

European corn-borer pupation reached the 50-percent level this week- -as reported by 
Earl Lutz, the Gallatin County Extension Adviser, at Ridgway. Further north, pupation 
is well underway. Emergence in northern Illinois should be underway in 2 to 3 weeks, 
depending on the temeprature. Not much corn will be susceptible to first-generation 
damage . 

HOMEOWNER 

You can prevent ants, water bugs, spiders, crickets, and other insects from entering 
your home by spraying the outside foundation wall with a 2-percent chlordane water 
emulsion. Purchase chlordane as a liquid concentrate and mix it with water to the 
proper strength (1 pint of 45-percent chlordane in 3 gallons of water gives a 2-percent 
solution) . Spray the foundation wall from the soil to the sill area, or along the outer 
wall for a distance of about a foot above the soil to the point of runoff. In addition, 
spray 5 to 4 inches of soil adjacent to the wall and the expansion joints along porches 
and steps, plus the edges of walks. In homes with a crawl space, spray the inside wall 
of the foundation and any supporting pillars. Do not spray shrubbery or flowers, be- 
cause the oil in the spray may burn the tender foliage. 

Three gallons of finished spray should do for the average house. The need for using 
insecticides inside the home will be greatly reduced by using this type of treatment. 

Ticks are annoying campers, picnickers, hikers, fishermen, and other persons. They 
cling to the vegetation along paths in and near wooded areas, waiting for man or other 
warm-blooded animals to come along. They attach themselves by embedding their mouth- 
parts into the skin. When entering wooded areas or ones suspected of being tick-infestei, 
use a repellent on socks, pants, pants cuffs, and exposed parts of the body to prevent 
tick bites. DEET (diethyltoluamide) is one of the best tick repellents. To control 
ticks in the home yard as well as in parks or playground areas, spray the grass, shrubs, 
and flowers with diazinon, malathion, or carbaryl (Sevin). Do not apply diazinon to 
ferns or hibiscus, malathion to Cannaert red cedar, or carbaryl to Boston ivy. 

There are scattered reports of eastern tent-caterpillar infestations. These insects 
form nests of webbing in the crotches of tree limbs --especially wild cherry, willow, 



-3- 

and fruit trees. The caterpillars feed on the foliage outside their web nests, often 
completely defoliating the trees. If control is necessary, apply a spray containing 
carbaryl (Sevin) , using 2 tablespoons of the 50-percent wettable powder per gallon of 
spray . 

Tree borers - -attacking oak, ash, apple, birch, and similar trees- -have previously been 
controlled by DDT. DDT is now prohibited for sale or use in Illinois. Other control 
measures include keeping the trees in a vigorous growth condition by applying ferti- 
lizer or by wrapping the trunks of newly planted trees and other young ones with spe- 
cial paper. Dimethoate (Cygon) has been effective against these borers- -especially 
the bronze birch borer. Treatment of infested trees should be made in mid- to late 
May. 

Euonymous scale hatch has begun, and these crawlers are moving onto new leaves and 
stems . Another name for euonymous is wintercreeper. Where this insect is a problem, 
apply malathion as a spray- -thoroughly covering the bark and leaves. Make two to 
three applications on the infested shrubs. Space the applications about 10 days apart. 
The first application should be in mid-May in the southern part of the state, during 
the latter part of May in the central section, and in early June in the northern area. 



WEEDS 



Several new herbicide names are appearing. Many of the products are not new, but are 
combinations of existing products. Some of these are listed below: 

Solo naptalam (Alanap) + chlorpropham (Chloro-IPC) 

Whistle Same as above 

Amoco Soybean Weed Killer Same as above 

Noraben norea (Herban) + chloramben (Amiben) 

Shamrox DCPA (Dacthal) + linuron (Lorox) 

Amilon chloramben (Amiben) + linuron (Lorox) 

Londax propachlor (Ramrod) + linuron (Lorox) 

Primaze atrazine (AAtrex) + prometryne (Caparol) 

The primary purpose of herbicide combinations is to control more weeds under a wider 
range of soil and climatic conditions, while reducing crop injury and sometimes cost. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , College 
of Agriculture , University of Illinois at U 'rb ana-Champa ign , and the Illinois Natural 
History Survey. 

WEEDS: M.D. McG lamer y , Department of Agronomy. 

AG COMMUNICATIONS : Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



In 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT. WEED & PLANT DISEASE SURVEY BULLETIN 



rATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 7, May 15, 1970 



This series of weekly bulletins provides a general look at the insect s weed, and plant 
disease situation (fruit and oorrmeroial vegetables excepted) , along with suggested 
abbreviated control measures. Each individual should check his own fields to determine 
local conditions. m U(8MRy Qf ^ 



INSECTS 



JUN 18 1970 



FORAGE 



ynlVeWSITY Of ILLINOIS 
AT UHBANA^HAMPAIGN 

Alfalfa weevils are heavier this spring than during either of the last two years. 

Populations are high, and damage is evident in most fields south of U.S. Highway 136. 

Pupation is progressing rapidly. Wasp parasites are helping some to reduce the number 

of weevils. Eggs are still hatching, however, so populations are expected to remain 

high for another two to three weeks . 

Larvae can be found north of U.S. Highway 136. Feeding is noticeable but not severe. 
Some fields north of this line may need treatment within the next week or two. The 
greatest injury in this area could be on the new growth of second-crop alfalfa. 

As you continue to check fields for damage, judge each field separately. The weevil 
population varies greatly from field to field. Do not apply insecticides unless they 
are needed. Applying insecticides is justified when there is apparent feeding on 
25 percent or more of the terminals and the field is more than two weeks from harvest. 
If the field is showing moderate to severe damage and is less than two weeks from 
harvest (particularly in the southern section), cut and remove the crop. Cutting 
will often reduce the weevil population, since many eggs are removed and a good many 
larvae are either killed or forced to pupate by exposure to the sun. Watch the new- 
growth closely; if it does not green-up within a few days and if worms are still 
present, apply a treatment promptly. 

The insecticide recommendations are: 

1. Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphos- 
methyl (Guthion) . Die" azinphosmethyl only once per cutting. Do not harvest for 

15 days after treatment with methyl parathion, or 16 days for azinphosmethyl. Wear 
protective clothing. 

2. Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per acre, 

(2) a mixture of 3/4 pound of malathion and 3/4 pound of methoxychlor per acre, 

(3) a mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor 
per acre, or (4) 1-1/4 pounds of malathion per acre on days when air temperatures 
will be above 60° F. for several hours after application. Do not harvest for 7 

days after treatment with Imidan, methoxychlor, diazinon, or mixtures of them. There 
is no waiting period for malathion. Do not apply Imidan more than once per cutting. 



5. Azinphosmethyl or methyl parathion should not be used on fields close to harvest 
that need treatment. Switch to one of the other suggested insecticides, such as 
malathion, that has no waiting period. 

Clover leaf weevils are present in all clover and alfalfa fields. Populations are 
generally low. A fungus disease has killed many of them in the central and southern 
sections. 

Pea aphid populations on clover and alfalfa remain light, and no damage is evident. 
Some pea aphids are being killed by parasites. These are the brown ones (not green) 
that are attached to the leaves. 

Potato leafhoppers are continuing to migrate into Illinois from the south. These are 
the tiny, green, wedged-shaped insects that skid sideways when disturbed. They cause 
a yellowing of second- and third-crop alfalfa. No control measures are needed now. 

CORN 

Black cutworm moths have been flying for several weeks . Watch the spots in cornfields 
that are low or wet, or the poorly drained, for damage. Cut or missing plants are a 
sign that cutworms may be at work. If damage appears, use a spray- -directed at the 
base of the plants- -of carbaryl (Sevin) at 2 or 3 pounds, diazinon at 2 pounds, toxa- 
phene at 3 pounds, or trichlorfon (Dylox) at 1 pound of actual chemical per acre. It 
is best to use at least 20 gallons of water per acre, and to cover the spray band by 
throwing soil at the base of the plants with a cultivator. 

Bristly cutworms and sod webworms are feeding on corn planted on sod. The worms are 
cutting the plants above the growing point, but the plants will recover. In two fields 
in the western section, feeding was observed on as much as 10 to 20 percent of the 
plants. No control will be needed unless the worms begin to eat the heart, causing 
the plants to die. Carbaryl (Sevin), diazinon, and trichlorfon (Dylox) --applied as 
suggested for black cutworms- -should provide effective control for these insects. 

Seed corn beetles are numerous in many cornfields or in those soon to be planted. 
Diazinon, Dasanit, Dyfonate, and phorate (Thimet) --applied as a 7-inch band ahead 
of the press wheel- -will control these beetles. Diazinon seed-treater will also 
prevent damage from this insect. 

Corn flea beetles were found feeding on newly- emerged corn this week. No serious injury 
has yet been reported. Watch closely sweet corn in the southern section that was 
planted early. These small, black, shiny beetles that jump when disturbed leave white 
scratch marks on the leaves. Damaged plants first turn white or silvery, and are some- 
times killed later on. If damage is severe and plants are being killed, apply 3/4 pound 
of carbaryl (Sevin) --preferred on dairy farms- -or 1-1/2 pounds of toxaphene per acre as 
a band spray over the row. To prevent additional flea beetles from moving into the 
corn, treat the grassy areas bordering the field. Do not use carbaryl near bee hives 
or toxaphene near fish-bearing waters. 

Corn borer pupation is well along in the southern part of the state, and a few moths 
have emerged. Pupation is just beginning in the central section. No pupation of borers 
has occurred in the northern area. Reports on corn -borer development were received this 
week from Les Rogers at Salem, Charles Orcutt at Marshall, Warren Bundy at Edwardsville, 
Bob Hayward at Mt. Sterling, Bill McAllister at Carlinville, Earl Lutz at Ridgway, and 
Jim Paullus at Rochelle. There are many overwintering borers in the southern and 
western sections. 



SMALL GRAINS 

Flights of true armyworm moths continue from states to the south. These moths are 
laying their eggs in grassy areas and in thick, rank stands of wheat, barley, and rye. 
Small worms were found in southern and south-central sections this week. Cool, wet 
weather favors the development of this insect. 

Do not confuse the striped armyworms with the transparent yellow-to-green sawflies . 
An armyworm has five pairs of abdominal prolegs ; sawflies, six or more pairs. Sawflies 
were found in many wheat fields this week. They do not damage wheat plants enough to 
require control. 

Treatment is justified if there are six or more armyworms per foot of drill row, as an 
average over the field. Applications of 1 to 1-1/4 pounds of malathion, 1 pound of 
trichlorfon (Dylox) , 1-1/2 pounds of carbaryl (Sevin) , or toxaphene will control army- 
worms. Do not apply carbaryl on small grains after the boot stage. Do not feed 
forage or straw treated with toxaphene or trichlorfon to dairy cattle , livestock 
being fattened for slaughter, or poultry. There is no waiting period between the 
application of toxaphene and grain harvest; a week is required when applying malathion, 
21 days for trichlorfon. 

HOMEOWNER 

Aphids are already appearing on some shrubs and trees. These small, soft-bodied in- 
sects (green-yellow, black, or red) suck the sap from terminal leaves, causing them 
to curl. You can control them by spraying the foliage thoroughly, using 2 teaspoons 
of 50- to 57-percent malathion or 25-percent diazinon emulsion concentrate per gallon 
of water. Do not use malathion on African violets or cannaert red cedar. Do not use 
diazinon on ferns or hibiscus plants. 

Tent caterpillars are feeding on a variety of trees. Two kinds, the eastern tent and 
forest tent caterpillars, are active right now. The forest tent caterpillars make no 
tent. Many worms (2 inches long) are now reaching maturity, and will stop feeding 
and spin cocoons- -usually on the tree trunks. If most of the worms are large, no 
insecticide treatment is needed. If most of them are still 1/2 to 1-1/2 inches long, 
they can be controlled by spraying with carbaryl (Sevin) , using 2 tablespoons of the 
50-percent wettable powder per gallon of water. 

Mosquitoes have become bothersome in many areas because of the wet weather. These are 
mainly the so-called "floodwater" mosquitoes. They breed in back-water areas or in 
the water standing in drainage ditches, low lands, and other temporary water-pool spots, 
Floodwater, or "temporary-pool," mosquitoes move from outlying to urban areas, and are 
more difficult for the individual homeowner to control . 

To help reduce mosquitoes in home yards, follow these steps: (1) Eliminate standing 
water in such places as eave troughs, old tires, tin cans, childrens' toys, storm 
sewers, etc., (2) Apply a water-base spray containing 1-percent malathion (2 ounces 
of 50- to 57-percent liquid concentrate per gallon of water) to shrubbery and tall 
grass. Repeat the treatment every week or two if needed., (5) Keep the screens on 
doors and windows in good repair., (4) Hang plastic resin strips (2 by 10 inches) 
containing 20-percent dichlorvos (DDVP)--one strip per 1,000 cubic feet of space, or 
about one per room. These strips will kill mosquitoes and flies for 4 to 6 weeks. 
Do not use these strips in kitchens or other areas where food is handled. Do not 



-4- 

use them in any room where infants, the ill, or aged persons are confined. A 0.1- 
percent pyrethrum space spray- -applied from a pressurized spray can--can be used for 
quick knockdown in place of the dichlorvos resin strips. Frequent treatments will 
be needed during problem periods., (5) When entering mosquito -infested areas, use a 
repellent. One of the most-effective mosquito repellents is DHET (diethyltoluamide) ., 
(6) For quick knockdown at cookouts, outdoor parties, or picnics, use either 0.1- 
percent pyrethrum or 0.5-percent dichlorvos (DDVP) solution as an oil- or water- 
base, space spray. Spray the mist lightly beneath tables and chairs and into the 
air for a few feet around the area. Repeat the treatment as needed. 

Cereal product insects may be having lunch in your kitchen cabinets as uninvited house 
guests. Many kinds of beetles and moths attack stored food products . They can be 
found not only in packages or containers of food, but also in the cracks and crevices 
in and around cabinets or cupboards. Follow these three simple steps: 

1. Remove all food packages from the cabinets and examine a small amount from suspect 
packages under a bright light for signs of insects. 

2. Vacuum or carefully brush-out all cabinets and shelving. 

3. Spray the entire inside surface of the empty cabinets with a 0.5-percent diazinon 
or 5.0-percent methoxychlor-oil solution from a pressurized spray can. 



WEEDS 
DELAYED HERBICIDE APPLICATION 

How late after corn planting can you still apply a "preemergence" herbicide? This is 
a common question, particularly because of the recent rains. If the weeds and corn 
have not emerged and there is adequate moisture for herbicide activity (and there 
probably is), most herbicides will still be effective. 

If the corn and weeds are just emerging, avoid using some of the herbicides with close 
crop tolerances, such as Knoxweed, Londax, and Primaze. If the weeds and corn have 
just emerged, consider rotary hoeing--where possible --along with a herbicide treatment. 
The rotary hoe will control some of the emerging weeds; the incorporation will also 
improve the effectiveness of the herbicide you use. 

If the grasses have emerged but have not reached the two-leaf stage, you can apply 
Ramrod 65W (liquid form) and Ramrod/ atrazine as an early, postemergence treatment. 
These treatments still require rain within 5 to 7 days for best results . 

If weeds are past the one- to two-leaf stage, consider an early, postemergence herbicide 
treatment such as atrazine and oil. An AAtrex (atrazine) plus oil treatment is most 
effective when the weeds (especially grasses) are no more than 1 to 2 inches tall. The 
usual rate for grass control is 2-1/2 pounds, per acre of AAtrex SOW, plus 1 gallon of 
special oil formulated for crop spraying. Occasionally, this treatment has injured 
corn, under stress conditions such as excess moisture. 

The most-economical and effective postemergence treatment for most broadleaved weeds 
in corn is 2,4-D. You can spray over the top until the corn is 8 inches high. On 
taller corn, use drop nozzles (extensions) to keep the 2,4-D out of the corn whorls. 
Be sure to apply no more than the recommended rate. For 2,4-D, that varies with the 
formulation and the strength (the number of pounds per gallon) . 



-5- 

Banvel (dicamba) is less likely to injure corn than 2,4-D, but is much more likely to 
drift and injure nearby soybeans, vegetables, or ornamental plants. Banvel controls 
smartweed better than 2,4-D, but is more expensive. 

HERBICIDES ON SEED BEANS 

Several herbicides are cleared for use on "seed beans." This restriction on a label 
means that soybeans harvested from land treated with such a herbicide can be used 
for replanting next year. They cannot be used for feed, food, or oil purposes, 
unless this restriction should be removed before such sale or usage. Preforan, 
Ramrod, and Londax are three herbicides that carry the "seed bean" restriction. 



MACHINERY 
CLEANING SPRAYERS 

Corrosion in sprayers occurs naturally anytime the equipment is left idle, especially 
when chemicals are also left in it. We suggest that sprayers be cleaned after each 
period of use. When you change chemicals, it is also important to clean-out the 
residue of the previous chemical. This will avoid the chance of reactions occurring 
between different chemicals , and of resulting contamination or damage to crops . 

When chemicals are being added to the tank, try to mix only the amount of spray 
materials you will be able to apply that day. And especially for the last tank, 
try to mix only enough chemical to finish the spraying job. Avoid having left-over 
spray material. 

Depending on conditions, it is a good idea to clean all screens and nozzles fre- 
quently. Do not use a metal object to clean nozzles. Clean them with air, water, 
or a toothpick. Nozzle openings are manufactured to close tolerances. One thrust 
with a metallic object will make a nozzle useless for accurate spraying. A damaged 
nozzle is difficult to detect; but if the pattern shows streaks, the nozzle has been 
damaged and should be replaced. 

To clean a sprayer, mix a small box, or about 2 pounds, of a nonsudsing detergent 

with 30 gallons of water in the sprayer tank. Circulate this mixture through the 

by-pass for 50 minutes. Then drain, allowing some to pass through the boom and the 
nozzles. 

If the spray material is water-soluble, a water rinse is sufficient after circulating 
the detergent. But if phenoxy herbicides such as 2,4-D or brushkillers are being 
used, an ammonia or charcoal rinse is necessary. 

For an ammonia rinse, fill the tank at least a third full with a solution of 2 quarts 
of household ammonia per 25 gallons of water. Circulate the ammonia solution and 
allow a small amount of it to flow through the nozzles. Let the remaining rinse 
stand overnight, and then run it out through the nozzles. After that, rinse the tank 
thoroughly with clean water. 

When you finish using the sprayer for the season, remove the nozzles and screens, 
coat them with oil, and store them with the sprayer booms and hoses in a cool, diy 
place. 



-6- 

READ THE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman , and Tim Coo ley , 
College of Agriculture , University of Illinois at Urbana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: M.D. McG lamer y , Department of Agronomy . 

MACHINERY: J.C. Siemens, Department of Agricultural Engineering . 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



141 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 8, May 22, 1970 



This series of weekly bulletins provides a general look at the insect, weed, and 

plant disease situation (fruit and commercial vegetables excepted) , along with 

suggested abbreviated control measures. Each individual should check his own fields 

to determine local conditions. 

THE LIBRARY OF THE 



INSECTS 



FORAGE INSECTS 



JUN 18 1970 

UHIV&fcSltY Qt IfcUINOIS 
AT UBIAN^eHAMPAIGN 



Alfalfa weevil populations continue high in fields south of State Highway 17. 
Damage is moderate to severe in fields south of U.S. Highway 40. Most fields in 
this area have been sprayed at least once; in some fields damage to the second 
crop is already severe and treatment is needed. Although the number of weevils is 
high, it has leveled off and is beginning to decline, as the pupation of the larvae 
continues and as the wasp parasites take their toll. 

In the area between highway 40 and 17, damage is light to moderate; most fields are 
close to harvest. Cutting alone, especially when temperatures are high, will reduce 
the number of worms, but watch the new growth closely. If it does not green-up 
within 2 to 4 days and worms are present, apply a treatment promptly. The number 
of worms is likely to remain high for another week or two in this area. 

North of State Highway 17, feeding is noticeable but is not of economic importance. 
Some fields may need treatment within a week or two. The greatest chance of injury 
could be on the new growth of the second crop. 

The insecticide recommendations are: 



Commercial applicators . Apply 1/2 pound per acre of methyl parathion or 
azinphosmethyl (Guthion) . Use azinphosmethyl only once per cutting. Do not 
harvest for 15 days after treatment with methyl parathion, or 16 days for 
azinphosmethyl. Wear protective clothing. 

Persons not equipped with protective clothing . Use (1) Imidan at 1 pound per 
acre, (2) a mixture of 3/4 pound of malathion and 5/4 pound of methoxychlor 
per acre, (5) a mixture containing at least 1/2 pound of diazinon and 1 pound 
of methoxychlor per acre, or (4) 1-1/4 pounds of malathion per acre on days 
when air temperatures will be above 60° F. for several hours after application. 
Do not harvest for 7 days after treatment with Imidan, methoxychlor, diazinon, 
or mixtures of them. There is no waiting period for malathion. Do not apply 
Imidan more than once per cutting. 



Spittlebug froth masses are numerous in many new seedlings of clover and alfalfa 
in the eastern and northern sections of Illinois. If there is an average of one 
or more nymphs per stem, control is profitable. Since it is best to control 
spittlebugs when the nymphs are still small and just beginning to form these froth 
masses, control with an insecticide is now late and should be used only if infest- 
ations are severe. For control, apply 3/4 pound of methoxychlor per acre. Allow 
one week to elapse between treatment and harvest when using methoxychlor. 

CORN 

Corn flea beetles are causing damage in an occasional field. These small, black, 
shiny beetles that jump when disturbed cause plants to turn white or silvery; some 
plants are killed. Corn can usually outgrow flea-beetle damage once it reaches a 
height of 10 to 12 inches. If damage is severe and plants are being killed, apply 
3/4 pound of carbaryl (Sevin) --preferred on dairy farms--or 1-1/2 pounds of toxa- 
phene per acre as a band spray over the row. To prevent additional flea beetles 
from moving into the corn, treat the grassy areas bordering the field. Do not use 
carbaryl near bee hives or toxaphene near fish-bearing waters. 

Black cutworms are present in corn fields , but no serious damage has been reported 
as yet. Watch the spots in corn fields that are low or wet, or poorly drained, for 
damage. Cut or missing plants are a sign that cutworms are at work. If damage 
appears, use a spray- -directed at the base of the plants --of carbaryl (Sevin) at 
2 or 3 pounds, diazinon at 2 pounds, toxaphene at 3 pounds, or trichlorfon (Dylox) 
at 1 pound of actual chemical per acre. It is best to use at least 20 gallons of 
water per acre, and to cover the spray band by throwing soil at the base of the 
plants with a cultivator. 

European corn-borer pupation is nearly complete in the southern section, and moth 
emergence is underway (17-percent emergence at Ridgway) . In the central section 
of the state, approximately 60 to 90 percent of the borers have pupated. This is 
somewhat ahead of the normal cycle. Pupation is just starting in the northern 
section. 

These reports on corn borer development were received from Jim Paullus at Rochelle, . 
Bob Hayward at Mt. Sterling, Charles Orcutt at Marshall, Warren Bundy at Edwardsville 
Earl Lutz at Ridgway, Paul Wilson at Pontiac, and Mike Sager at Eureka. Large, 
overwintering borer populations exist in the southern, west-central, and northwest 
sections of Illinois. 

In the southern section, first -generation corn borer problems should be light 
since only a few corn fields are mature enough for good borer survival. Peak egg- 
laying in this section is expected to occur during the first week of June. 

In the west and southwest parts of the central section and in the northwest section, 
the few fields of corn that were planted early could be seriously damaged by first- 
generation corn borers. However, if borers continue to develop ahead of schedule, 
the threat of severe damage will diminish. In these areas, be prepared to examine 
the fields that were early for borer feeding damage. Such fields should be examined 
in mid- to late June. 



-3- 

June beetles , the adult stage of white grubs are the large, brown, hard-shelled 
beetles (nearly an inch long) that fly toward lights at night and bump against win- 
dows and screens. They are emerging in large numbers from sod fields and others 
that were in soybeans in 1967. These beetles have a three -year life cycle. The 
adults will now lay eggs, and small white grubs will hatch and feed on plant roots. 
Little damage is expected in soybeans or corn this year, since the grubs will still 
be small. Next spring (in their second year), the grubs will be half to two-thirds 
grown, and will feed heavily throughout the season. Some fields in which corn and 
soybeans are rotated and where corn follows sod are likely to be damaged next year. 

SMALL GRAIN 

True armyworms can be found in thick, rank stands of wheat, barley, rye, and various 
grasses in the southern half of the state. Some fields may be heavily infested. 
Counts averaging as high as 6 per linear foot of row were observed in fields this 
week. Look in the thick or lodged spots first when checking for armyworms. They 
will be hidden in the dead leaves and other trash at the base of the plants. If 
you find lots of worms, make a count In several places in the field and figure the 
average number of worms per foot of drill row. If you find no worms or an occasional 
one in the thick or lodged spots, there is no need to look further. 

Continue to check for armyworms during the next week or two, since there could be 
additional egghatch. 

Do not confuse the striped armyworms with the transparent yellow-to-green sawf lies . 
An armyworm has five pairs of abdominal prolegs; sawf lies, six or more pairs. 
Sawf lies were found in many wheat fields this week. They do not damage wheat plants 
enough to require control. 

Treatment is justified if there are six or more armyworms per foot of drill row, as 
an average over the field. Applications of 1 to 1-1/4 pounds of malathion, 1 pound 
of trichlorfon (Dylox) , 1-1/2 pounds of carbaryl (Sevin) , or toxaphene will control 
armyworms. Do not apply carbaryl on small grains after the boot stage. Do not feed 
forage or straw treated with toxaphene or trichlorfon to dairy cattle, livestock 
being fattened for slaughter, or poultry. There is no waiting period between the 
application of toxaphene and grain harvest; a week is required when applying malathion, 
21 days for trichlorfon. 

HOMEOWNER 

Chiggers will be a problem soon. They annoy campers, hikers, picnickers, fishermen, 
berry pickers, and even homeowners in their own yard on occasion. These tiny mites 
cling to grasses and weeds, transfering to persons who happen to brush against them. 
When entering areas that may be infested, use a repellent such as DEET (diethyltolua- 
mide) . Apply the repellent on socks, pants, pant cuffs, as well as on exposed ankles 
and calves. Take a warm, soapy shower or bath as soon as possible after returning 
from a chigger- infested area. It takes the mites several hours to penetrate the 
skin; they can often be washed off before becoming imbedded. 

To reduce the number of chiggers in a home yard, spray malathion or diazinon lightly 
over the grass, low flowers, and shrubs. Do not apply diazinon to ferns or hibiscus, 
or malathion to cannaert red cedar. 



The number of f leas on dogs and cats is increasing. If left uncontrolled, they can 
become a serious problem in a home or home yard by late summer. In the worm (larva) 
stage these fleas live in the bedding of dogs and cats, rugs, upholstered furniture, 
and even in the dirt in flower and shrubbery beds. The worm stage is usually not 
noticed and is harmless, but adult fleas suck the blood of warm-blooded animals. 
Your dog or cat is a walking bait station for fleas. Bust them at least once a 
month during the warm weather (May to October) with either 4 -percent malathion or 
5-percent carbaryl (Sevin) . Treatments should also be made once or twice during 
the colder months (November to April) for added protection. 

Clothes moths and carpet beetles are getting ready for a summer's feast on improperly 
stored woolens. A small hole chewed in a piece of clothing may destroy its entire 
value. To keep woolens safe from damage by these insects, follow these suggestions. 

1. Dry-clean or wash woolens and place them in clean, plastic storage bags or 
other insect-tight containers. 

2. Woolens that are not dry-cleaned or washed should be hung in bright sunlight 
for a full day and brushed thoroughly before storing. Pay particular attention 
to pocket interiors, cuffs, and folds when brushing. 

5. If the storage area is not insect- tight (as is true of most closets, trunks, 
and boxes) , vacuum the container thoroughly and spray all inside surfaces with 
0.5-percent diazinon, applied from a pressurized spray can. 

4. Cedar- lined chests are usually insect- tight, but all fabrics need to be insect- 
free before storing. The cedar oil vapors destroy small larvae, but do not 
kill the larger ones. As added insurance in cedar chests, you can spray the 
inside surfaces as suggested above or use a fumigant material. Either napth- 
alene or PDB (paradichlorobenzene) is the fumigant commonly used in moth 
crystals, flakes, or balls. Use at least 1 pound of crystals, flakes, or 
balls for every 100 cubic feet of space. 

5. Woolens not placed in insect-free containers can be protected by treating in 
light amounts with 0.5-percent diazinon, from a pressurized spray can, or 
liberally moistened with fluoride-base fabric solution. Protection will last 

a year or more, unless the woolens are washed or dry-cleaned. Caution: Infants 
clothing should be washed or dry-cleaned before use . 

6. Good housekeeping practices will help reduce the number of these insects. Clean 
frequently to prevent lint and hair from accumulating, especially around radi- 
ators, baseboards, heating vents, and closets, as well as beneath large furni- 
ture and other hard-to-get-at places. If these places become infested, a light 
application of 0.5-percent diazinon will insure protection. 

Sawflies are feeding on pine needles, especially in Christmas tree plantings. If 
these dark-green caterpillars are defoliating pine trees, use carbaryl (Sevin) or 
diazinon. 



-5- 

WEEDS 
FIELD WEED CONTROL 

Corn. If you did not get your herbicide on at planting time, you may still have 
some flexibility. Ramrod or Ramrod- atrazine can be applied until grass weeds are 
in the two- leaf stage. Corn that is up has enough tolerance to Ramrod and atrazine, 
so let weed size be your guide. Atrazine and oil can be used until the weeds are 
1-1/2 inches tall. But there has been occasional corn injury with atrazine and 
oil- -especially under wet, cool stress conditions. Do not add 2,4-D or Banvel to 
atrazine and oil, because of the increased risk of corn injury. Another "no no" 
is Lasso after corn emergence. 

If you used Sutan and if some grasses have started to emerge, do not get excited 
prematurely. They will probably curl and die. With atrazine, too, some weeds may 
emerge and then die. You need not spend too much time trying to "start them down." 
The rotary hoe will usually do much more good than harm, even if a herbicide has 
been used for corn or beans . 

One of the major weaknesses of using Ramrod- atrazine is often the lack of velvet- 
leaf control. If velvetleaf gets started, use good cultivation and/or 2,4-D as 
an early postemergence treatment. 

If the weather should turn wet and cool, avoid spraying 2,4-D on corn under stress 
conditions . 

Smartweed . It is prevalent in many areas again. A lot of folks have asked about 
spraying this weed with 2,4-D or Banvel before working the seedbed. Smartweed 
is not easily controlled with 2,4-D. If you are considering Banvel, be certain 
there are no susceptible plants in the area. Modern tillage equipment should give 
a weed- free seedbed in most fields. And atrazine applied almost any approved way-- 
alone or in combination, surface or incorporated, pre- or postemergence- -usually 
can be counted on for good smartweed control. 

If you expect to have smartweed problems in soybeans, kill any existing weeds with 
good seedbed preparation. And remember the value of Chloro IPC- -used at 2 to 5 
pounds per acre active on a broadcast basis, or proportionately less in a band. 
It comes as a 4-pound-per-gallon EC, or as granules. Apply it to the surface. Do 
not incorporate. Chloro IPC can be used alone or following previously incorporated 
Treflan. Some of the other Chloro IPC combination treatments are being tested 
more extensively this year. 

Do not use Banvel on smartweed where you plan to plant soybeans. The use of 2,4-D 
on smartweed before soybean planting may or may not give good results. The 2,4-D 
may or may not affect soybeans, depending on the rate and formulation, rainfall, 
soil moisture, temperature, and the interval between application and planting. 

Soybeans . Since some corn herbicide applications were delayed because of rain, 
soybean herbicides need to be on before or at planting time. If this is not done, 
we do not have many alternative postemergence herbicides to suggest for soybeans. 
Dinitro is only for very early postemergence use. Tenoran can be used on broad- 
leaved weeds up to 2 inches tall, and may help some on small grass. Tenoran may 
have some noticeable effects on beans, but damage to them usually is not severe. 
2,4-DB is a possibility a little later. Although these postemergence treatments 
for soybeans may be helpful in certain situations, none of them have had much 
acceptance in Illinois. 



Silage corn . AAtrex, Ramrod, Ramrod- at razine, Sutan, Sutan-atrazine, Lasso, Lasso- 
atrazine, Londax, Eptam, and Knoxweed are all cleared. (For Lasso, at least 12 
weeks must elapse before harvesting or feeding immature corn forage to cattle.) 
AAtrex is also cleared for popcorn. For sorghum, check the details on the Ramrod 
and AAtrex labels; for sorghum- sudan, check the AAtrex label. 

2,4,5-T . This should no longer be used around homes, lakes, ponds, or ditchbanks. 
Consider substituting silvex, which will control many of the same species plus some 
others. 

Marihuana . It is now about 6 to 12 inches high in some areas, and this is a good 
time to spray with 2,4-D--"before it grows to pot." 

PASTURE WEED CONTROL 

The most-common herbicide spray for pasture weed control is 2,4-D, unless woody 
species are present; then, a mixture of 2,4-D and 2,4,5-T (brush-killer) is generall 
used. Choose the rate of 2,4-D to fit the weed problem. Most annual broadleaved 
weeds can be controlled with 0.5 pound per acre of 2,4-D (1/2 pint of a 4-pounds- 
to-the-gallon mixture) . 

Most of the other pasture weeds (biennials and perennials) can be controlled with 
1 to 2 pounds per acre of 2,4-D. This rate will eliminate most of the legumes in 
a grass -legume pasture. Do not spray seedling grasses or grasses in the boot stage 
(if for seed production) . Do not graze dairy animals on treated areas for 7 days 
after treatment. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , 
College of Agriculture, University of Illinois at Urbana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: Ellery Knake and M.D. McG lamer y , Department of Agronomy . 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



FIELD MEETINGS 



This year, we applied five soil insecticides in different ways to corn planted after 
sod. You are invited to view these fields during the first two weeks of June at 
1:30 p.m. on the following dates--insect infestation may or may not be noticeable, 
but we will dig for insects and count stands at that time: 

June 2 . Pike County- -Barry, Perry Metcalf farm. Contact Extension Adviser Harry 
Wright in Pittsfield. 

June 5 . Knox County- -Wataga, Robson farm. Extension Adviser Don Teel, Galesburg. 
Field 1/4 mile west and 1 mile north of junction of Highway 54 and the Wataga- 
Henderson Road. 



-7- 

June 4 . Livingston County, Mannville, Wilbur Burge farm. Contact Extension Adviser 
Paul Wilson in Pontiac, for the location near Long Point. 

This is a tentative schedule for meetings to be held in other counties : 

June 8, Ogle; June 9, Perry and Carroll; June 10, Tazewell and Winnebago; June 11, 
Boone; June 12, Vermilion and Kane. 



n 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



rATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 9, May 28, 1970 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and oommeroial vegetables excepted) , along with suggested 
abbreviated control measures. Each individual should check his own fields to deter- 
mine local conditions. 

Because of the long weekend this bulletin is being written one day earlier than 
usual. We hope no last-minute problems are overlooked. lbraryofthe 



INSECTS 



SMALL GRAINS AND GRASSES 



JUN 1 8 1970 

UNIVP&9ITY SF IWWINUIS 
AT URiANA^HAMPAIQN 



Armyworms are now present in wheat fields in many areas . Some luxuriant fields of 
wheat are infested as far north as central Illinois, but high temperatures are speeding 
up worm development as well as a disease that may kill many of the worms. Parasites 
are also present. The worms are still small in wheat fields along the east side of 
the state and there are many of them. Populations are lower and the worms are more 
mature in the western and southern sections. Although the time for maximum benefit 
is about over, some fields may still warrant the use of an insecticide. 

To determine the need for treatment, strike the plants vigorously, then count the 
worms on the ground or in the debris --even in the cracks and crevices in the row. If 
the average count is 6 or more worms per linear foot of drill row throughout the field, 
apply an insecticide when the worms are about 3/4 of an inch long. An armyworm eats 
39 linear inches of wheat leaf in its lifetime, but 80 percent of that feeding occurs 
after the worm is over 3/4 of an inch long. Leaf feeding is not serious when worm 
populations are low, but an average population of less than 6 worms per linear foot 
of drill row can still be damaging if the worms are cutting off the heads of the 
wheat. Also if most worms are about 1-1/4 to 1-1/2 inches long and are fat, they 
are through feeding. Do not use insecticides then; it is too late. 

Do not confuse the striped armyworms with the transparent yellow-to-green sawflies . 
An armyworm has five pairs of abdominal prolegs ; sawflies, six or more pairs. Saw- 
flies were found in many wheat fields this week. They do not damage wheat plants 
enough to require control. 

Treatment is justified if there are six or more armyworms per foot of drill row, as 
an average over the field. Applications of 1 to 1-1/4 pounds of malathion, 1 pound 
of trichlorfon (Dylox) , 1-1/2 pounds of carbaryl (Sevin) , or toxaphene will control 
armyworms. Do not apply carbaryl on small grains after the boot stage. Do not feed 
forage or straw treated with toxaphene or trichlorfon to dairy cattle, livestock 
being fattened for slaughter, or poultry. There is no waiting period between the 
application of toxaphene and grain harvest; a week is required when applying malathion, 
21 days for trichlorfon. 

Remember, toxaphene is very toxic to fish. Do not use it near fish-bearing waters . 
If there are honey-bee colonies adjacent to fields to be treated, toxaphene is the 



safest of the four to use; carbaryl is the most -dangerous one to use around the 
bees . 

CORN 

Black cutworm damage is still slight, and we are uncertain about activity by this 
pest. They cannot be written off yet as a potential problem. Five reports of 
damage thus far involved (1) no treatment; (2) aldrin, broadcast; and (3) failures of 
aldrin, diazinon, and phorate (Thimet) as band or row treatments. Broadcasting al- 
drin usually controls cutworms, as does diazinon on late-planted corn. However, 
aldrin and phorate applied in the row will not provide satisfactory control. 

Corn that was planted early can be severely damaged. When cutworms slice off the 
plants below the growing point the plant dies . This happens when the corn approaches 
12 inches in height. Thus, stands of early corn could be hurt now by cutworms, but 
corn planted recently or that being planted now may escape damage for at least 
another two weeks. Mien corn is cut off above the heart, the plant keeps right on 
growing- -in fact, may not even be slowed down. However, a late infestation of black 
cutworms in mid-June, as we had in 1958, could be devastating to all corn. 

If damage appears, use a spray- -directed at the base of the plants --of carbaryl 
(Sevin) at 2 or 5 pounds, diazinon at 2 pounds, toxaphene at 3 pounds, or trichlor- 
fon (Dylox) at 1 pound of actual chemical per acre. It is best to use at least 20 
gallons of water per acre, and to cover the spray band by throwing soil at the base 
of the plants with a cultivator. 

Common stalk borers attack corn alongside fence rows, grass waterways, and ditch 
banks , where they have overwintered as eggs . Mien the wo mis outgrow the grass or 
weed stems or the fence row is mowed, the borers migrate into the adjacent corn rows. 
Sometimes, an attack on young plants by the borers will wilt the plant; other times, 
will fail to produce an ear, even if it lives. These striped worms with a dark- 
purple band around their middle can be controlled by a spray of carbaryl (Sevin) as 
they migrate. It is too late to spray once they are in the corn plant and leaf 
ragging is apparent. Control is justified only in severe infestations. 

European corn borer pupation and emergence is a little earlier than usual, but the 
moths may concentrate in fields that were planted early to lay their eggs. Such 
fields can be found in most areas, and may suffer severe first -generation borer 
damage. However, any weather conditions that would delay the emergence of the 
moths and egg-laying could change this situation, increasing the possibility of 
a greater infestation. 

The pupation of overwintering corn borer is complete in southern Illinois, where 
the moths are flying and egg- laying is well underway. Pupation is almost complete 
in central Illinois, moth emergence has begun, and egg-laying will start soon. In 
northern Illinois, pupation is progressing rapidly, but no moth emergence has been 
noted as yet. 

The egg-laying period is usually about three weeks. Insecticides to control first- 
generation corn borers should not be applied to field corn until almost all eggs 
have hatched. Thus insecticide applications are usually made about three weeks after 
egg- laying begins. 

If corn is 50 inches tall (leaves extended) or more at that time and if 75 percent 
or more of the plants show any fresh whorl feeding, apply carbaryl (Sevin) or diaz- 
inon as granules . 






-3- 

CLOVER AND ALFALFA 

Alfalfa weevil development has been extremely rapid this week. In the northern part 
of the state, it is better to cut the first growth than to use an insecticide. Watch 
new growth carefully, and apply an insecticide if this is necessary to save the crop. 
Some new growth has already been damaged seriously. Now is also the time to think 
about an application of methyl parathion in November to kill overwintering adults, 
before they lay eggs for the 1971 alfalfa crop. This practice will prevent killing 
weevil parasites. 

Lesser clover-leaf weevil larvae are now feeding on buds and tunnelling into the stems 
Their feeding leaves dirty-looking channels. Stems often break over at the feeding 
point, and the stem dies. No control is needed. This insect usually arouses more 
curiosity than it does overall damage. 

HOMEOWNER PROBLEMS 

Armyworms are now feeding in lawns . The damage from these worms can be confused with 
that of lawn webworms . Although many of the armyworms are parasitized, control may 
be necessary. Use carbaryl (Sevin) at the rate of 2 ounces of 50 -percent wettable 
powder per 1,000 square feet of lawn area. Apply with at least 3 gallons of water 
per 1,000 square feet. 

Elm leaf beetle eggs are being laid, especially on Chinese elms. These eggs will 
hatch into dirty-yellow to black worms that will skeletonize the leaves from the 
underside. Spraying the tree with carbaryl (Sevin) when damage begins to appear 
will provide control. 

Dusting or spraying new plants of vine crops, such as melons and cucumbers will pre- 
vent injury from cucumber beetles , as well as from the bacterial wilt disease that 
these insects spread from plant to plant while they feed. Use carbaryl, 5-percent 
dust, or mix 2 tablespoons of the 50-percent wettable carbaryl powder per gallon of 
water . 



WEEDS 
WEED CONTROL 

Because of the poor corn stands caused by flooding or crusting, some farmers are re- 
planting corn or changing to soybeans. Consider the existing stand and the date before 
you decide to start over. There is a yield reduction from late planting, as well as 
from poor stand. 

If you decide to replant, consider the pesticides used on the first planting before 
choosing another crop and crop -protect ion program. Many of the pesticides cleared 
for use on corn are not cleared for soybeans. Some of the pesticides used on corn 
can significantly injure soybeans. Don't forget that double doses of chemicals with 
close crop tolerances can cause corn injury. 

AAtrex, Primaze, Sutan-atrazine, Ramrod- atrazine, or any other combinations with 
atrazine (AAtrex) will cause serious soybean injury if the soybeans are planted where 
the chemicals have been used earlier in the spring. Lasso and Lorox are cleared for 
use on corn and soybeans, but Ramrod and Londax only have a "seed bean" clearance 
for soybeans. Knoxweed is a mixture of EPTC and 2,4-D; and both materials can injure 
soybeans . 



If you broadcast your herbicide, you probably should not use another herbicide ap- 
plication, even though you've lost two to three weeks of effective weed control. If 
you banded the herbicide, consider "splitting the centers" between previous rows and 
using a second herbicide application. 

Remember' to read the label and follow the instructions. The rates specified are the 
basis for crop clearances and tolerances. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , 
College of Agriculture, University of Illinois at Urbana-Champaign, and the Illinois 
Natural History Survey. 

WEEDS: Ellery Knake and M.D. McG lamer y , Department of Agronomy. 

AG COMMUNICATIONS : Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



ANNOUNCEMENTS 



See last week's letter for June 2-4 soil insecticide field meetings. Meetings for the- 
week of June 8 at 1:30 p.m. are: 

June 8. Ogle County. The Herb and Rich Coffman farm. Contact Extension Adviser 

Stan Eden in Oregon for the location. (815) 732-2191. 

June 9. Perry County. Contact Extension Adviser Charles R. Howell in Pinckneyville 

for the location. (618) 357-5671. 

June 9. Carroll County. The Ron Iske farm near Brookville. West of the junction of 

Routes 52 and 64, on the gravel road- -second farm on the south side. Harold Brinkmeier, 

Extension Adviser, Mt. Carroll. 

June 10. Winnebago County. The Pieratt Johnson-Clem Meissen farm. One-fourth mile 

west of Owen Center -Elmwood Road Junction, about 2 miles north of Rt. 20, on the west 

side of Rockford. Dick Kerr, Extension Adviser, Rockford. 

June 10. Tazewell County. Contact H. David Myatt in Pekin for the location. 

(309) 347-2855. 

June 11. Boone County. The Clyde Curtis farm, north of the junction of Routes 73 

and 176, to the Quail Trap Road; west to the third set of buildings on north side. 

Wallace Reynolds, Extension Adviser, Belvidere. 

June 12. Vermilion County. The Richard Fourez farm. Contact Extension Adviser 

John Bicket in Danville. (217) 442-8615. 

June 12. Kane County. The James Foley farm. First set of buildings north of the 

junction of Rt. 51 and the Red Gate Road- -west side of Rt. 31. Philip Farris , 

Extension Adviser, St. Charles. 

[ Special note to Extension advisers : We have had, as usual, an occasional report of 
fish being killed in farm ponds . Please check these out and notify us of the insec- 
ticide used in adjoining fields; also, about the fertilizer and formulation used, 
the herbicide used, the presence of barnyard runoff, and any other factors that 
might be peculiar to the situation.] 



.4i 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 10, June 5, 1970 



This series of weekly bulletins provides a general look at the insect, weed, and plant 

disease situation (fruit and commercial vegetables excepted) , along with suggested 

abbreviated control measures. Each individual should check his own fields to determine 

local conditions. >r , w __ TLIC . 

THE LIBRARY OF THE 



INSECTS 



CORN 



JUN 2 9 1 Q 70 

UNIVtKSlf* Oh ILLINOIS 
AT URBANA-CHAMPAIGN 



Cutworms are the major insect problem this week- -primarily the black species, with an 
occasional infestation of the variegated species. These worms have been cutting off 
corn plants at or below the soil surface. They are not necessarily confined to the 

I low areas of fields as is usually the situation but are found throughout a corn field. 

'Also, the size of the worms in an infested field may range from ones almost full-grown 
(about two inches long) to young worms (a half inch or less in length) . Where soil 

[moisture is low, the worms are feeding below the surface of the soil. Where the soil 

'surface is moist, however, the worms are feeding on or near the surface. 

In many instances, worms tunnel into the base of taller plants and kill them. Corn 
; plants cut off below the growing point will die. In general, corn that is less than 

12 inches tall will recover from cutworm damage. But if many small worms are present 
j (as in many fields now) , cutworm damage could continue for another 10 to 14 days . 

I Some of the cutworm- infested fields were treated with a row application of either 
aldrin or heptachlor at planting time. Decisions on applying emergency treatments 
will vary from field to field. It is important to check the fields closely and to 
carefully evaluate the damage being done. Some infested fields are wet, thus pre- 
venting any ground application of an insecticide. Don't depend on aerial applications 
I of cutworm emergency treatments to give consistent control. If the corn is more than 
i 8 inches tall and 20 percent or more of the plants have been attacked, emergency treat- 
ment is warranted. Use a spray- -directed at the base of the plants- -of carbaryl 
! (Sevin) at 2 or 3 pounds, diazinon at 2 pounds, toxaphene at 3 pounds, or trichlorfon 
j (Dylox) at 1 pound of actual chemical per acre. It is best to use at least 20 gallons 
of water per acre, and, if possible, to cover the spray band by throwing soil at the 
I base of the plants with a cultivator. 

If replanting becomes necessary, the cutworms will probably still be present when this 
j is done. Diazinon or Dyfonate granules will probably provide the best control. Use 
them at 2 pounds of actual insecticide per acre, banded ahead of the planter press 
wheel . 

European com-borer development continues to progress more rapidly than usual. Egg- 
laying in the southern part of Illinois probably peaked during this past week. The 



-2- 

emergence of the moths is complete in the south-central section, three - fourths complete 
in north-central Illinois, and just beginning in the northern area. 

If treatment is needed in southern Illinois, this would probably be applied during the 
week of June 8. Cool temperatures can slow-down borer development, allowing the corn 
plants to reach a more desirable height. If corn is 50 inches tall (leaves extended) 
or more by the week of June 8, and if at least 75 percent of the plants show any whorl 
feeding, apply carbaryl (Sevin) or diazinon as granules. 

Rootworm eggs have already begun to hatch. If you plan to apply a basal application 
of soil insecticide, this should be done immediately; if possible, also cultivate in 
order to incorporate the insecticide. We have had many questions about the effect of 
heavy spring rains on planting-time treatments of soil insecticides. The insecticides 
we have suggested for 1970 performed well during 1969 under heavy rainfall conditions. 
We expect the same to be true this season. 

SMALL GRAINS AND GRASSES 

Armyworms can still be found in many wheat fields in southern and central Illinois. The 
greatest number is along the eastern side of the state. One disease and a number of 
parasites are killing many of the worms. In some localities, armyworms have migrated 
to corn fields from wheat fields or grass areas. Although no report of cutting-off 
wheat heads has been received, this could happen as the wheat begins to ripen. 

To determine the need for treatment, strike the plants vigorously, then count the worms 
on the ground or in the debris- -even in the cracks and crevices in the row. If the 
average count is 6 or more worms per linear foot of drill row throughout the field, 
apply an insecticide when the worms are about 3/4 of an inch long. An armyworm eats 
39 linear inches of wheat leaf in its lifetime, but 80 percent of that feeding occurs 
after the worm is over 5/4 of an inch long. Leaf feeding is not serious when worm 
populations are low, but an average population of less than 6 worms per linear foot 
of drill row can still be damaging if the worms are cutting off the heads of the 
wheat. Also if most worms are about 1-1/4 to 1-1/2 inches long and are fat, they are 
through feeding. Do not use insecticides then; it is too late. 

Treatment is justified if there are six or more armyworms per foot of drill row, as 
an average over the field. Applications of 1 to 1-1/4 pounds of malathion, 1 pound of 
trichlorfon (Dylox) , 1-1/2 pounds of carbaryl (Sevin), or toxaphene will control army- 
worms. Do not apply carbaryl on small grains after the boot stage. Do not feed for- 
age or straw treated with toxaphene or trichlorfon to dairy cattle, livestock being 
fattened for slaughter, or poultry. There is no waiting period between the appli- 
cation of toxaphene and grain harvest; a week is required when applying malathion, 
21 days for trichlorfon. 

Remember, toxaphene is very toxic to fish. Do not use it near fish-bearing waters. 
If there are honey-bee colonies adjacent to fields to be treated, toxaphene is the 
safest of the four to use. Carbaryl is the most dangerous one to use around bees. 

Where there is migration into corn, spray the infested rows as well as a 25- to 30-foot 
strip of wheat adjacent to the corn. 

CLOVER AND ALFALFA 

Alfalfa weevil damage is common in many unmowed fields in the central section of the 
state. In the southern third of Illinois, weevil activity has slowed down very much. 
Some newly-mowed fields show damage to the new growth of the second crop. It is better 
to cut the first crop and spray the new growth before it is damaged. 



-3- 



SOYBEANS 



Bean leaf beetles are feeding in some soybean fields, on the underside of bean leaves. 
Unless feeding is severe, no control is needed at this time. Sprays of carbaryl or 
toxaphene will control these beetles. 

LIVESTOCK INSECTS 

Pasture flies are increasing, particularly in the central and southern sections of 
Illinois. Horn flies , stable flies , and face flies rob you of milk or beef produc- 
tion. Don't let flies pick your pocket. Follow these suggestions. 

For control on dairy cattle, apply Ciodrin as a 2-percent oil or water-base spray- - 
at a rate of 1 to 2 ounces per animal two to four times per week. A 1-percent 
dichlorvos (DDVP) or a 0.1-percent pyre thrum spray, applied at 1 to 2 ounces per 
animal each day, can also be used. Pay particular attention to the animal's legs 
and undersides when spraying. For dry stock and young stock on pasture, or for 
lactating animals, use a 1-percent Ciodrin, water-diluted spray. Apply 1 to 2 pints 
per animal, as often as once per week if needed. Ciodrin is the most- effective 
insecticide for face- fly control. All of the above insecticides provide good con- 
trol of horn flies and fair control of stable flies. 

To control pasture flies on beef cattle, apply a water-base spray of 0.5-percent 
toxaphene, using 1 to 2 quarts per animal every three weeks. Toxaphene provides 
excellent control of horn flies, fair control of stable flies, and poor control of 
face flies. 

If face flies become a serious problem, use Ciodrin as suggested for dairy cattle. A 
canvas or burlap head-oiler or back-oiler, saturated with a solution 5-percent tox- 
aphene in oil, will provide some relief against face flies. Do not apply toxaphene 
to beef cattle within 28 days of slaughter. 

HOMEOWNER PROBLEMS 

Bagworms are starting to hatch from eggs that overwintered in spindle-shaped bags on 
trees and shrubs, especially junipers. The newly-hatching worms feed on foliage, 
grow, and construct their bag. In southern Illinois, the hatch should peak during 
the first week in June. The peak will hit central Illinois by June 15. In northern 
Illinois, egg-hatch should be almost complete by the end of June. If treatment is 
necessary, apply a spray containing carbaryl (Sevin) , diazinon, or malathion. Do 
not use malathion on cannaert juniper. For best results, apply sprays while the 
worms are small. 

Grape flea beetles are still feeding on grape leaves. Both bluish-green adult beetles, 
which jump when disturbed, and their young larvae are commonly found feeding on the 
new grape foliage, thus stunting the new cane growth. Either carbaryl (Sevin) or 
malathion sprays or dusts will control this insect pest. 

Bronze birch borer adults, a pest of birch trees, are emerging from under the bark 
of the upper limbs. The symptoms of bronze borer damage first appear in the tops of 
affected trees. The upper limbs become weak and die as the borers tunnel under the 
bark, leaving characteristic raised rings around the limbs. These raised areas may 
be present on limbs that appear to be healthy, but are infested with borers. If 
borer symptoms are present, apply treatment during early June with a spray containing 
dimethoate (De-Fend and Cygon) . ' Follow the directions on the container for mixing 
the spray. Repeat the treatment two weeks later. Keeping the birch trees in a vig- 
orous growing condition will reduce the chances of borer injur)'. 



Sawflies are now about half-grown. They are feeding on and defoliating pine plantings 
especially white pines in eastern Illinois. These worms can be controlled with a 
mixture of 2 pounds of carbaryl (Sevin) per 100 gallons of spray. 



WEEDS 

> 
ATRAZINE-OIL TREATMENTS 

The wet spring and the rush to plant corn has caused many farmers to put off the appli 
cation of a preemergence herbicide. The resulting weed problems have created a renewe 
interest in the atrazine-oil treatment. 

The phytobland (nonphytotoxic) oils used in this treatment should meet certain stand- 
ards for purity, viscosity, and emulsifier content. Purity is expressed as an unsul- 
fonated residue (UR) value. A 90 -percent UR value indicates a 10 -percent content of 
aromatic sulfonated residue. Phytobland oils should have a UR value of more than 
90 percent. 

Viscosity is expressed as SSU (Seyboldt Seconds Universal) values, indicating the time 
required for a given quantity of oil to pass through a funnel orifice test. A 100 SSU 
oil is more viscous than a 70 SSU one. Common viscosities for these oils are 90 to 
150 SSU. 

The oils are used at the rate of 1 gallon mixed with about 20 to 40 gallons of water 
per acre. Thus, an emulsifier must be added so the water and oil will mix completely. 
The usual emulsifier content is 1 to 2 percent. The emulsifier must be kept free 
from water until final mixing occurs, otherwise the oil may not emulsify with the 
water. 

Agricultural surfactants are sometimes used rather than oil. Surfactants offer the 
advantage of a lower quantity of spray additive, because they are used at the rate 
of 1 to 2 quarts per 100 gallons of spray. The comparative performance of oils and 
surfactants are often about equal; if there is a difference, it is usually in favor 
of the oils. Thus there is current interest in a 4-to-l ratio of oil and surfactant, 
used in combination at the rate of 1 quart per acre- -combining the advantages of both 
oil and surfactant. 

Some spray applicators use household detergents rather than oils or agricultural sur- 
factants. These are usually more expensive and less effective than agricultural sur- 
factants or phytobland oils. Some detergents also cause problems with foaming of 
sprays and surging of pumps and nozzles. 

The AAtrex (atrazine) rate is 2-1/2 pounds per acre 80W (2 pounds per acre ai). For 
maximum results, the treatment should be applied before grass weeds are 1-1/2 inches 
tall. The atrazine-oil postemergence treatment sometimes causes corn injury- - 
especially on corn that has been under stress from prolonged cold, wet weather prior 
to spraying and that begins its active, succulent growth after spraying. 

HERBICIDE INJURY 

How do you recognize herbicide injury? Agronomy Fact Sheet W-31, Recognizing and 
Reducing Herbicide Injury (which was included in the Pesticide Dealer and Applicator 
Clinic packets), helps answer that question. It is also available from the Agronomy 
Department. This fact sheet covers the causes and symptoms of herbicide injury and 
the methods of reducing it. 



-5- 



When you go to diagnose a case of crop injury, be sure to look at roots as well as 
the tops. Also take into account all the potential sources of injur)', such as her- 
bicides, insecticides, diseases, insects, water damage, wind erosion, compaction, 
and crusting. Be sure to get all the facts. 

MARIHUANA IDENTIFICATION 

There have been several reports of weeds that resemble marihuana, but are hairy and 
have yellow flowers. These plants are upright cinquefoil {Potentilla recta) --not 
marihuana {Cannabis sativa) . They both have digitately compound leaves, but 
cinquefoil is a perennial and marihuana is an annual. 

Marihuana also has separate male and female plants (dioecious) and blooms much later 
than cinquefoil, which is beginning to bloom now. Some of the buttercups (Ranunculus 
spp.) are often confused with cinquefoil. They have deeply divided leaves and could 
also be mistaken for marihuana. 

WELL SAFETY 

We have received questions about chemicals getting in wells. The most-frequent 
causes are the flushing or overflowing of sprayers near wells or the siphoning of 
hoses while filling sprayers. It would also be possible, if a loss of pressure 
occurs, to get chemicals' from a spray tank into a muncipal water supply by siphoning. 

Prevention is cheaper and easier than the cure. Here are some suggestions: 

1. Do not leave the sprayer unattended when filling the tanks. 

2. Do not flush tanks where a chemical will drain into wells. 

3. Do not place the hose in the tank. A bracket to hold the hose and the tank will 
prevent siphoning. The inovative handyman can probably design an anti-siphoning 
device. 

What to do if the material gets into the well is another matter. First, determine 
the use of the well. Is the water used for human or animal consumption? Is the 
well used to irrigate a garden? Second, determine the chemical (s) involved and 
their toxicity. Third, start pumping the well as soon as possible, and dispose of 
the water in a suitable manner. Some materials such as Treflan, Lasso, or 2,4-D 
ester will be visible in water in very dilute amounts. 



READ THE LABEL' AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Coo ley , 
College of Agriculture , University of Illinois at Urbana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: M.D. McG lamer y , Department of Agronomy . 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



ANNOUNCEMENTS 

t 

See last week's letter for June 2-4 soil insecticide field meetings. Meetings for 
the week of June 8-15 at 1:30 p.m. are: 

June 8. Ogle County. The Herb and Rich Coffman farm. Contact Extension Adviser 

Stan Eden in Oregon for the location. (815) 732-2191. 

June 9. Perry County. Contact Extension Adviser Charles R. Howell in Pinckneyville 

for the location. (618) 357-5671. 

June 9. Carroll County. The Ron Iske farm near Brookville. West of the junction of 

Routes 52 and 64, on the gravel road--second farm on the south side. Harold Brinkmeier, 

Extension Adviser, Mt. Carroll. 

June 10. Winnebago County. The Pieratt Johnson-Clem Meissen farm. One-fourth mile 

west of Owen Center- Elmwood Road Junction, about 2 miles north of Rt. 20, on the west 

side of Rockford. Dick Kerr, Extension Adviser, Rockford. 

June 10. Tazewell County. Contact H. David Myatt in Pekin for the location. 

(309) 347-2835. 

June 11. Boone County. The Clyde Curtis farm, north of the junction of Routes 73 

and 176, to the Quail Trap Road; west to the third set of buildings on north side. 

Wallace Reynolds, Extension Adviser, Belvidere. 

June 12. Vermilion County. Tne Richard Fourez farm. Contact Extension Adviser 

John Bicket in Danville. (217) 442-8615. 

June 12. Kane County. The James Foley farm. First set of buildings north of the 

junction of Rt. 51 and the Red Gate Road- -west side of Rt. 31. Philip Farris, 

Extension Adviser, St. Charles. 

June 15. Menard County. The Elmer Behrends farm near Petersburg. It is located 

4-1/2 miles west of Petersburg on the Snake Hollow road, north side of the road. 

Contact Extension Adviser Elmer Rankin in Petersburg. (217) 632-7491. 

June 17. Ford County. The Paul Malone farm, two miles north of Cabery on Route 115. 

Go 1-3/4 miles west on the campus blacktop. Contact Extension Adviser James 

Neuschwander in Melvin. (217) 388-7791. 

[ Special note to Extension advisers : We have had, as usual, an occasional report of 
fish being killed in farm ponds. Please check these out and notify us of the insec- 
ticide used in adjoining fields; also, about the fertilizer and formulation used, 
the herbicide used, the presence of barnyard runoff, and any other factors that 
might be peculiar to the situation.] 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




«ECT WEED & PLANT DISEASE SURVEY BULLETIN 



iTE/COUNTY/LOCAL GROUPS U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 11, June 12, 1970 



This series of weekly bulletins' provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures . Each individual should check his own fields to determine 
local conditions. RARY of THE 



INSECTS 



JUN 2 » Vrii 



INOIS 



Black cutworms still rate the "insect of the week" award. However, the worms are 
maturing rapidly and damage should decline. Check your corn for cut or missing plants -- 
a sign that the cutworms are at work. If plants are being cut above the growing point 
and if the worms are larger than 1 inch, the outbreak will be over shortly and the corn 
will continue to grow. However, immediate treatment is needed if the plants are being 
cut below the growing point and if many of the worms are less than an inch long. Use 
a spray- -directed at the base of the plants--of carbaryl (Sevin) at 2 to 5 pounds, 
diazinon at 2 pounds, toxaphene at 3 pounds, or trichlorfon (Dylox) at 1 pound of 
actual chemical per acre. It is best to use at least 20 gallons of water per acre 
and to cover the spray band by throwing soil at the base of the plants with a culti- 
vator. 

Corn-borer development generally appears to be ahead of the corn, thus lowering borer 
survival and reducing the threat of serious damage. However, in many areas, the most- 
mature corn fields may become heavily infested. 

In the southern section of Illinois, egg-hatch reached its peak this week. Most of 
the corn in that area is too small for borer survival. The tiny borers already present 
in fields where the corn is less than 40 inches high will die. In many of the fields 
of 50-inch or taller corn, 75 to 100 percent of the plants are infested. If needed, 
treatments should be applied now. 

In the central section, moth -emergence is nearly complete and egg- laying is reaching 
its peak. Treatments, if needed, should be applied during the week of June 21. 

In the northern section, 40 to 60 percent of the moths have emerged and egg-laying is 
underway. 

To determine the need for treatment, measure the tassel ratio. Dig up a plant and mea- 
sure from the bottom of the plant to the tip of the longest leaf. Split the plant and 
find the developing tassel. Measure from the bottom of the plant to the tip of the 
tassel. Divide the tassel height by the plant height and multiply by 100. If the tas- 
sel ratio is 30 or over and if 75 percent or more of the plants have corn-borer feeding 
on the whorl leaves, the field should be treated- -but not until the tassel ratio is at 
least 35, preferably 40 to 50. The percentage of infested plants required to justify 
treatment can be reduced with higher tassel ratios . 



-?- 



Use 1 pound of actual diazinon in granular form per acre of 1-1/2 pounds of carbaryl 
(Sevin) as granules. For spraying, use the same amount of actual insecticide per 
acre, and direct the spray to the upper third of the plant. Aerial applications should 
be granules, not sprays or dusts. Allow 10 days between treatment and the ensiling of 
corn when applying diazinon; carbaryl has no waiting period. Commercial applicators 
may prefer to use parathion at 1/2 pound actual per acre, which will provide good con- 
trol of the corn borer. Parathion has a 12-day waiting period between treatment and 
harvest . 

Reports on corn-borer development were received from Warren Bundy at Edwardsville , 
Bob Hayward at Mt. Sterling, Jim Paullus at Rochelle, and Mike Sager at Eureka. 

Com rootworm egg-harch will continue over the next several weeks. The peak number 
of larvae is expected in early to mid-July. Many fields of continuous corn in the 
northern half of Illinois may be affected, even though there were fewer adult root- 
worms in 1969 than for several years. Fields of second-year corn, north and west of 
a line from Carthage to Bloomington, to LaSalle, to Joliet may be damaged by the 
western corn rootworm . The concentration of northern corn rootworms is greatest 
north of U.S. Highway 36, often presenting a problem where corn has been grown con- 
tinuously for three or more years in the same field. 

If you know about or suspect that you have a rootworm problem and did not use an 
organic phosphate or carbamate insecticide at planting time, apply one within the 
next two weeks. Use granules applied at the base of the plants, and cover them by 
cultivation. The insecticides suggested for basal treatment are BUXten, Dasanit, 
or phorate (Thimet)--at the rate of 1 pound of actual chemical per acre. 

Common stalk borers are moving out of the grasses and weeds found in fence rows , road- 
sides, grass waterways, and ditchbanks and into the border rows of corn. These whitish- 
brown, striped worms with a distinct purple band around their middle feed in the whorl 
of the corn. The emerging leaves will have irregular holes in them. Plants may be 
severely damaged, sometimes killed, by these insects. Control in corn is difficult, 
because the worms are usually too deep in the whorl for insecticides to reach them. 
In cases of severe infestations try the following suggestion: 

Mow the grasses and weeds from which the borers are migrating. A rotary mower would 
be best, in order to help kill some of the worms during cutting. This will drive the 
worms out of these areas and into the corn. Therefore, spray the mowed area and the 
first few rows of corn immediately with 1-1/2 pounds of actual carbaryl (Sevin) per 
acre. This should help reduce further infestations and additional damage. 

Thrips are common in corn whorls, especially in the southern section of the state. 
Both the yellow and black grass thrips are present. They are tiny (about 1/16 of an 
inch) and leave tiny streaks of white mottling on the leaves. The feeding damage is 
being mistaken for that caused by flea beetles, which leave a more -distinct , white 
groove or scratch mark on the leaves. When numerous, the thrips, cause a field to 
take on a silvery appearance. Insecticides are seldom needed to control thrips on 
corn. However, if severe damage occurs, a spray of 1 pound of malathion per acre 
directed into the whorl should control them. 

SMALL GRAINS 

The threat from true armyworms is subsiding as the worms mature and various diseases 
and parasites take their toll . Scattered reports have been received of armyworm mi- 
grations from grass pastures, hay fields, and wheat into corn. Large areas of small 
corn can be damaged overnight by a hungry horde of armyworms. 



/atch for armyworm migrations as your wheat begins to turn and ripen, or when you 
low grassy areas if these are adjacent to small corn. If migration occurs, spray 
±ie corn as far out as the worms have migrated. Also, spray 2 to 3 rods into the 
/heat or grassy area, as well as all over any fence row or lane through which the 
rorms are moving. For migrations from wheat to corn, use 1-1/2 pounds of toxaphene 
ier acre. For migrations from grass fields into corn, use 1-1/2 pounds of carbaryl 
Sevin) per acre. Remember that toxaphene is toxic to fish and that carbaryl is 
:oxic to bees. 

'ORAGE CROPS 

;he alfalfa weevils still need watching. In the southern section, a large number of 
idult weevils are damaging the new growth of the second crop in fields that have been 
:ut recently. These adults will continue to feed for another week or two before tak- 
ing their summer siesta. Most of the insecticides used for larval control are not 
effective against the adults. Methyl parathion is effective, but should be applied 
inly by commercial applicators. Be sure to allow 15 days between treatment and har- 
dest or pasturing. 

[n the central, north - central , and northern sections of Illinois, the larvae are 
zausing economic damage in many fields of first-crop alfalfa. It would be best to 
;ut and remove the crop and to watch the new growth for damage. If that new growth 
ioes not green-up within 2 to 4 days and if worms are present, apply an insecticide 
oromptly. 

."or control, farmers making their own applications should use malathion; Imidan, a 
aixture containing malathion and methoxychlor; or a mixture of methoxychlor and 
iiazinon (Alfatox) . Commercial applicators can use the above materials or one of 
the more-toxic insecticides, such as methyl parathion or azinphosmethyl (Guthion) . 

-ollow label directions for dosages, harvest limitations, and precautions. 

anall grasshoppers are appearing in fence rows, ditchbanks, grassy waterways, and 
lay fields- -particularly in the southern section of the state. There is a greater 
lumber of overwintering grasshopper eggs than has existed for several years. The 
southwestern, southern, and western sections are the ones where problems are most 
Likely. 

fiany more grasshoppers will be hatching during the weeks ahead. Hot, dry leather is 
Eavorable for survival during the hatching period. If you notice lots of tiny 'hoppers 
Ln grassy areas or hay fields, plan to control them before they move into more -valuable 
zrops , such as corn and soybeans. Spray grassy areas with 1-1/2 pounds of toxaphene 
3r 3/4 pound of carbaryl (Sevin) per acre. Use carbaryl (Sevin) on hay fields or 
Dastures. There is no waiting period for carbaryl (Sevin). 

4ites , probably two -spotted spider mites, are damaging soybeans in the west -southwest 
section. Hot, dry weather favors their development. Rain would tend to lessen their 
lumber, and would allow the plants to grow out of the damage. The mites appear as 
small, orange or black spots on the undersides of the leaves. Usually, a fine web is 
also present. Affected soybeans show stunting, yellowing, and eventual browning of 
the leaves. 

If damage is severe and treatment is needed, spray with 1/2 pound of azinphosmethyl 
(Guthion) or 5/4 pound of carbophenothion (Trithion) per acre. 

these insecticides should be app l ied only by experienced operators. 



Azinphosmethyl has a 21-day waiting period between treatment and harvest; carbopheno- 
thion, a 7 -day waiting period. Do not feed soybeans sprayed with these insecticides 
as forage to dairy cattle or livestock being fattened for slaughter. 

Potato leafhoppers , both nymphs and adults, are numerous in some alfalfa fields. They 
reduce hay yields as well as the quality of the hay by lowering the content of Vitamin 
A and protein. These leafhoppers cause a yellowing of second- and third -crop alfalfa. 
Treatment is indicated if swarms of these small (1/8 inch), green, wedge-shaped in- 
sects are observed during cutting or on the new growth of the second crop. Use either 
carbaryl (Sevin) or methoxychlor, at 1 pound per acre. When using methoxychlor, allow 
7 days to elapse between treatment and harvest. There is no waiting period for carbar> 
(Sevin) . 

STORED-GRAIN INSECTS 

Stored-grain insects are lying in wait for the wheat harvest, which is just around the 
corner in the southern part of Illinois. To protect stored wheat from insect damage, 
follow these steps : 

1. Sweep-up and clean-out all the old grain, chaff, and other debris from inside and 
around the outside of the storage bin. Also clean-out the combine, auger, and 
other grain -handling equipment. You can clean the combine by discarding or feed- 
ing to livestock the first 2 or 3 bushels that pass through. 

2. To the ceiling, walls, and floor of the bin, apply a water-base spray of 1.5- 
percent, premium-grade malathion (mix 3 ounces of 50- to 57 -percent, malathion - 
emulsion concentrate per gallon of water), or a 2.5-percent methoxychlor spray 
(mix 14 ounces of 25 -percent, methoxychlor -emulsion concentrate per gallon of 
water) . 

3. If the wheat is to be stored for a month or longer, treat it with a premium-grade 
malathion dust (40 to 60 pounds of 1 -percent dust per 1,000 bushels), or spray 

(using 1 pint of 50- to 57-percent emulsion concentrate in 3 to 5 gallons of water 
per 1,000 bushels). The dust can be applied best to the wheat when it is in the 
combine hopper; the spray, as the wheat is augered or elevated into the bin. Give 
the surface grain a light treatment after all the grain is in the bin. 

4. Re inspect the grain once each month to be certain that your control program is 
effective. Last year some stored wheat that had been treated with premium-grade 
malathion became infested with Indian meal moths by mid- to late August, indicat- 
ing a possible resistance of this insect to malathion. 

Use malathion as directed . A report has been received that one large grain company 
refused to buy wheat treated with malathion because of the objectionable odors. Be 
sure the malathion you use is labeled for use in stored-grain insect control, and, 
therefore, is of the low-odor type. Do not overdose, and do not apply malathion if 
you plan to ship the grain within a week or two. Apply a grain fumigant for quick 
kill, if insects are present and the grain is to be shipped soon. 

HOMEOWNER PROBLEMS 

Sod webworm moths appeared this week around lights and in tall grass and shrubbery. 
They fly a zig-zag pattern over lawns during the early evening, laying eggs that 



will produce the first generation of worms. This generation is seldom numerous enough 
to cause damage. But the second generation --that comes during late July, August, and 
early September --often presents problems. Watch the lawn for damage. If control is 
necessary, use carbaryl (Sevin) , diazinon, or trichlorfon (Dylox) as sprays or granules, 

Bagworms have hatched in the southern area of the state. Sprays should be applied im- 
mediately. In the central section, the target date for spraying is after June 15; in 
the northern portion, after June 50. 

For best results, spray while the worms are still small and easy to kill and before 
damage is evident. Use carbaryl (Sevin), diazinon, or malathion. Malathion will also 
provide fair control of any mites that may be present. Follow the recommendations on 
the label and check carefully for the plants that could be injured by the insecticide 
you use . 

Aphids are present on many trees and shrubs , and on some flowers such as roses . In 
most instances, the plant will not be seriously damaged by aphids. However, if the 
leaves begin to curl and dry, apply a spray using 2 teaspoons of 50- to 57-percent 
malathion or 25-percent diazinon liquid concentrate per gallon of water. Do not use 
malathion on African violets or cannaert red ceder. Do not use diazinon on ferns or 
hibiscus plants . 



WEEDS 



DIRECTED POSTEMERGENCE APPLICATIONS FOR EMERGENCY USE IN CORN 

We have received several questions about grass -control materials, after it is too late 
to use the atrazine-oil treatment. The cultivator is still a valuable weed-control 
tool, and its use at the right time can take care of many of the weed problems. 

Directed sprays of Lorox and Dowpon can be used in emergency situations, when grass 
weeds are too tall for control by cultivation. You must have a significant height dif- 
ferential between the corn and the weeds in order for these treatments to be effective. 

Dowpon (dalapon) can be applied as a directed spray when corn is 8 to 20 inches tall, 
from ground to whorl . Use leaf lifters to keep the spray off the corn leaves . Dowpon 
will translocate into the corn plant, causing stunted and deformed plants. Do not 
let the spray contact more than the lower half of the stalk, and do not direct the 
spray more than 7 inches above the ground. The rate of use for Dowpon is 2 pounds 
of actual chemical per acre (broadcast basis). Use proportionately less, depending 
on the coverage. 2,4-D can also be added to the spray to control broadleaved weeds. 

Lorox (linuron) may be applied as a directed spray after the corn is at least 15 inches 
high, but before weeds are 5 to 8 inches tall. Lorox will control both grasses and 
broadleaved weeds --if you cover the weeds with the spray and keep it off the corn as 
much as possible. Any corn leaves that are sprayed will be killed. Use 1-5/4 to 5 
pounds per acre of 50 -percent Lorox, on a broadcast basis, or proportionately less 
in a directed band. Surfactant WK should be added at the rate of 1 pint per 25 gal- 
lons of the spray mixture. 

CLIMBING MILKWEED 

This is sometimes called bluevine. It is a deep-rooted perennial vine, not an early 
emerging weed. Hence, it is necessary to control other weeds in the corn with pre- 
emergence herbicides or cultivation, or both, in order to get good spray coverage on 



the climbing milkweed. Apply the treatment when the weeds are spreading on the groun 
and before they start to climp up the corn. 

To obtain optimum coverage, use herbicides with a surfactant, enough water volume, 
and a suitable nozzle set-up. Use 2,4-D at 1/2 pound per acre (1 pint of 4-pound-per 
gallon product). The date of application will depend on plant development, but is 
usually in late June or early July. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman , and Tim Cooley , 
College of Agriculture , University of Illinois at Urb ana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: M.D. McGlamery and E.L. Knake , Department of Agronomy . 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



ANNOUNCEMENTS 



Soil insecticide field meetings for the week of June 15 at 1:30 p.m. are: 

June 15. Menard County. The Elmer Behrends farm near Petersburg. It is located 
4-1/2 miles west of Petersburg on the Snake Hollow Road, north side of the road. 
Contact Extension Adviser Elmer Rankin in Petersburg. (217) 632-7491. 

June 17. Ford County. The Paul Malone farm, two miles north of Cabery on Route 115.! 
Go 1-3/4 miles west on the campus blacktop. Contact Extension Adviser James 
Neuschwander in Melvin. (217) 388-7791. 



Al / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



■v*e 



UBB^ 



of 



"Vrfc 



FOR IMMEDIATE RELEASE 






^ 



<&$&#* 



Art ovSNo. 12, June 19, 1970 



2%£s series of weekly bulletins -provides a gene$*fj$,\}&%ffiCat the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures . Each individual should check his own fields to determine 
local conditions. 



INSECTS 



CORN 

European corn-borer infestations should be watched carefully for the next three weeks . 
Wait until you are sure treatment is warranted, but do not allow fields to suffer 
noticeable economic loss. 

A few cornfields (1 to 5 percent of the total) everywhere are much more advanced than 
others. In the south, west, and northwest parts of the state, such fields either show 
or will soon show noticeable feeding on the whorl leaves. In the east, central, and 
northeast sections (where overwintering borer populations were low) , fewer fields will 
be affected. 



In southern Illinois, small borers will soon leave the whorl as the tassels emerge and 
enter the stalk. Once there, they are difficult to reach with insecticides. This 
will occur within the next week in those very early fields. Thus, the time to apply 
insecticides has almost gone by in the area south of a line across the state opposite 
St. Louis. Eggs are still being deposited on corn north of this line almost up to 
Rock Island- -with a few fields, particularly on the west side of the state, already 
meeting the standards for profitable insecticide application. The optimum timing will 
be during the next two weeks. 

The emergence of moths is almost complete in northern Illinois, and egg-laying is just 
starting. A few fields will probably be damaged. The optimum time period for applica- 
tions to field corn will probably start 10 days to two weeks from now. 

In general, the storms of this past week killed some moths. This will help reduce the 
overall, first -generation borer population. Nevertheless, watch those early fields 
closely. 

To determine the need for treatment, first check the tassel ratio. Dig up a plant and 
measure from the bottom of the plant to the tip of the longest leaf. Split the plant 
and find the developing tassel. Measure from the bottom of the plant to the tip of the 
tassel. Divide the tassel height by the plant height and multiply by 100. If the tas- 
sel ratio is 30 or over and if 75 percent or more of the plants have corn-borer feeding 
on the whorl leaves, the field should be treated- -but not until the tassel ratio is at 
least 35, preferably 40 to 50. The percentage of infested plants required to justify 
treatment can be reduced with higher tassel ratios . 



-2- 

Use 1 pound of actual diazinon in granular form per acre or 1-1/2 pounds of carbaryl 
(Sevin) as granules. For spraying, use the same amount of actual insecticide per 
acre, and direct the spray to the upper third of the plant. Aerial applications shoulc 
be granules, not sprays or dusts. Allow 10 days between treatment and the ensiling of 
corn when applying diazinon; carbaryl has no waiting period. Commercial applicators 
may prefer to use parathion at 1/2 pound actual per acre, which will provide good con-; 
trol of the corn borer. Parathion has a 12 -day waiting period between treatment and 
harvest. 

Southwestern corn borers in the extreme southern counties usually follow the pattern 
of the European corn borer. The number of southwestern borers is usually not serious 
until the second and third generations --from late July through September. No chemical 
control is recommended at this time. 

Corn leaf aphids may be around this year . Some are already present . They certainly 
have a wide selection of planting dates from which to choose. No control is recommends 
as yet. 

Armyworm moths --the brown or buff-colored, heavy-bodied moths- -will become numerous 
within the next three to four weeks. They will be emerging from wheat fields in centra 
and southern Illinois, where these worms were generally found. A few moths have alreac 
appeared. Cornfields with grassy weeds should be checked during late July and August 
for infestations. No control is needed now. 

Cutworms are maturing rapidly. Corn that was cut off above the growing point is grow- 
ing back; but in corn that was planted early, cutting was below the growing point and 
the plants died. Most worms are now 1-1/2 inches long or more, and will be pupating 
and emerging as moths later. Our fear is that with the wet weather, the moths that 
emerge from fields infested early may soon deposit their eggs in low spots within othei 
fields. If this happens there could be serious damage. This is more likely to happen 
in northern Illinois than in the central or southern sections, since these moths tend 
to migrate northward. i 

If plants are still being cut above the growing point and if worms are larger than 1 
inch, the outbreak will be over shortly and the corn will continue to grow. However, ; 
immediate treatment is needed if the plants are being cut below the growing point and 
if many of the worms are less than an inch long. Use a spray --directed at the base 
of the plants --of carbaryl (Sevin) at 2 to 3 pounds, diazinon at 2 pounds, toxaphene 
at 3 pounds, or trichlorfon (Dylox) at 1 pound of actual chemical per acre. It is 
best to use at least 20 gallons of water per acre and to cover the spray band by 
throwing soil at the base of the plants with a cultivator. 

Corn rootworm eggs are now hatching. If you expect a rootworm infestation but did 
not use a rootworm insecticide at planting time, make a basal application as soon as 
you can get into the field. 

As a result of the recent rains , we do not know whether the rootworm insecticides 
applied at planting will provide the usual control; also, whether the water standing 
in the fields has drowned some rootworms . Where the corn is still short, you can 
check for a basal application in about a week; where the corn is tall, it is already 
too late . 

In general, in fields where a rootworm insecticide was applied at planting time, no 
basal application will be needed, unless there has been excessive soil erosion. For 
a basal application we suggest BUXten, Dasanit, or phorate (Thimet) . 



SMALL GRAINS 

English grain aphids are showing up on the wheat heads in some fields , particularly 
on the east side of the state. The wheat is maturing rapidly, and these insects 
usually do very little damage after the kernels approach the dough stage. Therefore, 
insecticides should be used only in fields that are maturing exceptionally late. 
Even there, the average aphid count should be at least 25 per wheat head- -an aver- 
age of 50 may be more realistic. 

LIVESTOCK INSECTS 

Barn flies are becoming bothersome, particularly in central and southern sections. 
The population is expected to increase rapidly from now on, because of the excessive 
moisture and high temperatures. 

The house fly and the blood-taking stable fly (needle-like beak) make up the barn-fly 
complex. Both flies spend 90 percent of their time sitting on barn walls, support 
posts, fences, and the like, and only about 10 percent of their time on the animals. 
Therefore, there is no need to spray cattle kept on dry lot. Begin control efforts 
now before the flies become too numerous . The following program will provide good 
results: 

1. Practice good sanitation . Eliminate fly-breeding materials- -such as manure, rotting 
straw, wet hay and feed- -as often as possible. Spreading this refuse where it can 
dry makes it unsatisfactory for fly development. 

2. Apply a barn spray to the point of run-off on the ceilings and walls of all live - 
stock buildings . Also spot-spray outside around windows and doors and along 
fences in the lot. The following insecticides are suggested for this purpose: 

Amount 
per 100 

gallons Length of 
Insecticide of water control 

Diazinon, 50-percent wettable powder. . . .16 pounds 2 to 4 weeks 

Dimethoate, 23-percent (Cygon) liquid 

concentrate 4 pounds 4 to 6 weeks 

Revap (Rabon plus dichlorvos), liquid 

concentrate 4 gallons 4 to 6 weeks 

Ronnel, 24-percent (Korlan) liquid 

concentrate 4 gallons 1 to 5 weeks 

Ronnel, 25-percent wettable powder 52 pounds 1 to 3 weeks 

Use only ronnel in poultry houses. All materials are cleared for use in dairy, 
beef, swine, sheep, and horse barns. Cover feed and water troughs before spray- 
ing. Do not spray animals with these materials at the dosages suggested. Remove 
animals before spraying the barns. Do not spray the milk storage room. 



3. Supplement good sanitation and barn sprays with a spray bait material . Use 2 to 
4 ounces of dichlorvos (DDVP) or naled (Dibrom) in a mixture of 1 gallon of clear 
corn syrup and 1/2 gallon of warm water. Apply this from a small tank sprayer to 
the favorite fly-roosting areas . 

i 
Barn foggers using insecticides like dichlorvos (DDVP) , pyrethrum, or naled 
(Dibrom) give a quick kill of flies during the fogging operation (5 to 10 min- 
utes) , but the effect is not lasting. When fly populations become intense, even 
twice a day fogging fails to provide satisfactory fly control for the farm- -even 
though the barn is kept temporarily free of flies. As normally used, fogging 
does not leave enough insecticide deposit on the animals to protect the cattle 
from flies when on pasture. Coarse sprays applied to the animals are best for 
this purpose. 

HOMEOWNER PROBLEMS 



Many tree leaf samples that are infested with galls have been sent in or observed. 
Some of the more-common ones include maple bladder on maple, various galls on oak, 
and pod gall on honey locust. These are warty -appearing growths that develop on the 
leaves. They rarely cause any damage to branches of the tree. Chemical control is 
difficult, since the tiny insect forming the gall is inside it. If treatment is 
desired, it will be most effective just before the gall is formed; in most instances, 
this is in the spring as the new leaves are emerging from buds. Hence, this should 
be planned for next spring. 

Lecanium scale is appearing on oak trees as well, as on some yews and arbor-vitae 
shrubs . These dark brown or red, bead- like scales are found along the branches at 
the base of the leaves. Eggs usually hatch under these scales during late June, with 
the crawlers moving onto new growth. If such scales are present and are causing 
damage, spray now with malathion to control the young crawlers. 

A species of spittlebug is feeding on juniper shrubs. These appear as small frothy 
masses of spittle on the needles; the insect is inside the frothy mass. These insects 
can be controlled with methoxychlor, carbaryl (Sevin) , or malathion. Do not use 
malathion on cannaert red cedar. 



ATRAZINE AND OIL 



WEEDS 



It is now too late for postemergence treatments with atrazine and oil. Most weeds 
are too large, and late applications increase the chance of residue problems next 
year- -especially if the weather turns dry. 

Preemergence or postemergence treatments with atrazine have helped to control smart- 
weeds in many areas. Where smartweeds are still a problem, Banvel can help; but 
extreme precautions are needed in order to avoid injury to nearby soybeans and other 
desirable plants. If the Banvel moves into soybeans, it can cause considerable 
damage to the plants. The signs of damage are cupped and crinkled leaves; also, the 
leaf buds not opening normally. Yield reductions may result, especially if Banvel 
gets on the soybeans near the bloom stage. 

2,4-DB may be used as a postemergence treatment on soybeans 7 to 10 days before bloom 
to mid-bloom, when soybeans are about knee-high. This can be helpful in controlling 
cocklebur, annual morningglory, and giant ragweed. But 2,4-DB can cause some wilting 



-5- 

and can increase lodging in soybeans. The stems may show some cracking and prolifera- 
tion at the base. We suggest using 2,4-DB only where these weeds are serious and only 
if the grower is willing to risk some injury to soybeans. 

POSTEMERGENCE TREATMENTS FOR CORN 

2,4-DB and Banvel (dicamba) are the two top choices for broadleaved weed control in 
corn. 

2,4-D will control most of the annual broadleaved weeds effectively and economically. 
Use "drop pipes," or nozzle extensions from the boom, to keep the spray out of the 
corn whorl if you spray after the corn is more than eight inches tall . Do not spray 
with 2,4-D after corn begins to tassel. 

The rate of 2,4-D to apply depends on the strength of the concentrate and the type of 
2,4-D used--amine or ester. If you use the amine form, apply one-half pound of the 
active ingredient per acre. That is 1 pint of the 4 -pound material per gallon of 
material. If you use the ester form, apply one-sixth to one-fourth pound per acre. 

The amine form is less likely to cause drift problems, but most farmers consider the 
ester form more active and less likely to wash-off with a rain. Weeds are easier to 
kill when they are small, so adjust the rate of application to the weed size. 

CORN INJURY 

Each year 2,4-D damages some corn. The symptoms are an elbowing of the stalk, abnormal 
brace roots, and "onion leafing." Corn seems most susceptible to 2,4-D damage when it 
is under cool, wet-weather stress, or when it is growing fast during hot, humid periods. 
Corn stalks are often brittle for 7 to 10 days after spraying with 2,4-D, so delay culti- 
vation if possible. 

Banvel is cleared for use on corn until the crop is 56 inches high, or until 10 days 
before the tassels emerge. Banvel is similar to 2,4-D, but it provides improved smart- 
weed control. Banvel often affects soybeans near treated cornfields, causing a cupping 
of the soybean leaflets about two weeks after the drift occurs. The soybeans generally 
outgrow the injury, and yields are not affected. To minimize Banvel drift, use a low 
pressure and avoid spraying when the wind velocity is more than 5 miles per hour. 

Both Banvel and 2,4-D can injure corn. Banvel is cleared for use over the top of the 
corn, but the use of drop nozzles generally lessens the chance of corn injury. Remember: 
injury most often occurs when the corn has been under cool, wet -weather stress. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , College 
of Agriculture , University of Illinois at Urbana-Champaign , and the Illinois Natural 
History Survey. 

WEEDS: M.D. McGlamery and E.L. Knake , Department of Agronomy. 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



A REQUEST 

Please put spiders and other insects in a separate, closed vial inside a mailing tube 
when you send them to us for identification. If desired, alcohol can be used in the 
vial. Please do not put live insects and spiders loose in a mailing tube . When the 
lid is taken off, they come out! (Good secretaries are hard to find!) 

H.B. Petty 



m 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 






Rf^RV 



Of ( 






HE 






lvN jlS 



FOR IMMEDIATE RELEASE 



M * y 



^PW<3* 



No. 13, June 26, 1970 



T/zis ser-tes o/ weekly bulletins provides a general look at the insect, weed,and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures . Each individual should check his own fields to deter- 
mine local conditions. 



INSECTS 



GENERAL 

Grasshoppers increased noticeably last year, and deposited eggs that overwintered. 
The big, green differential grasshoppers deposited eggs in fencerows, grass sods, 
ditchbanks, and roadsides. The smaller, red-legged grasshopper layed eggs in al- 
falfa, clover, and other hay fields. These eggs are now hatching. 

Hard, beating rains will kill newly hatched grasshoppers, but will not kill them 
after they are a few days old. Although some of the overwintering eggs may have 
hatched during the recent rains and some tiny grasshoppers may have been killed, 
the hatch continues. The grasshoppers hatched more recently may survive. 

You may find these tiny grasshoppers all over where soybeans or corn was planted 
on hay-crop ground. Or, you may find them in this year's hay crop as the eggs were 
layed in it last fall. Of course, the tiny differential grasshoppers can still be 
found in fencerows and ditchbanks. If these tiny grasshoppers are very numerous, 
as they are now in many areas, it will be easier to control them now while they are 
small than it will be later. 

In fencerows, apply carbaryl (Sevin) , diazinon, malathion, naled (Dibrom) , or toxa- 
phene. In hay fields, use the same materials except for toxaphene. Cut the hay and 
drive the grasshoppers into an occasional uncut swath you have left. Then, spray it. 
Carbaryl and malathion at 1 pound per acre require no waiting period after application; 
naled requires 4 days; diazinon, 7 days. 

Provide protection around the edges as the grasshoppers migrate into soybeans. If the 
migration is prolonged, you may have to spray the borders several times. Always read 
the label for more -detailed restrictions. 



CORN 



European corn borer populations were not too severe in any of the fields examined 
this week. In general, about 5 to 10 percent of the fields in any area are mature 
enough for a high survival of the borers. Only 10 to 20 percent of such fields have 
enough borers to warrant the use of an insecticide. In the area south of a line 
through St. Louis, it is too late for optimum results by using an insecticide. A 



-2- 

few eggs are still being deposited in the area north of St. Louis, south of Rock 
Island, and west of Route 51. The borers are entering the stalks, and the time for 
best results from applying an insecticide is almost over. In northern and eastern 
Illinois, the time to apply an insecticide will be this coming week. The number of 
borers is low in eastern Illinois, and only a few fields require protection. 

To determine the need for treatment, first check the tassel ratio. Dig up a plant 
and measure from the bottom of the plant to the tip of the longest leaf. Split the 
plant and find the developing tassel. Measure from the bottom of the plant to the 
tip of the tassel . Divide the tassel height by the plant height and multiply by 
100. If the tassel ratio is 30 or over and if 75 percent or more of the plants have 
corn-borer feeding on the whorl leaves, the field should be treated- -but not until 
the tassel ratio is at least 35, preferably 40 to 50. The percentage of infested 
plants required to justify treatment can be reduced with higher tassel ratios. 

Use 1 pound of actual diazinon in granular form per acre, or 1-1/2 pounds of car- 
baryl (Sevin) as granules. For spraying, use the same amount of actual insecticide 
per acre, and direct the spray to the upper third of the plant. Aerial applications 
should be as granules, not sprays or dusts. Allow 10 days between treatment and the 
ensiling of corn when applying diazinon; carbaryl has no waiting period. Commercial 
applicators may prefer to use parathion at 1/2 pound actual per acre, which will pro- 
vide good control of the corn borer. Parathion has a 12-day waiting period between 
treatment and harvest. 

Black cutworms are still around, although they seem to be decreasing in number. We 
had several calls from eastern Illinois this week. Again, we say that in fields of 
corn in the rotary-hoe stage, cutworms cut plants above the growing point or heart. 
About 60 to 80 percent of these plants will grow into healthy stalks. So, do not 
disk-up such fields. The taller corn plants may be killed, since the worms cut off 
the plant below the heart. 

Control varies. We have had reports of failures from practically all planter-time 
treatments, including aldrin and heptachlor. In fact, we have had several complaints 
about failures of these materials even when they were broadcast. Sprays of toxaphene 
and carbaryl (Sevin) have given varying results. In some instances, control has been 
almost perfect ; in others , control was only moderate . We hope to have methods next 
year that will provide more -cons is tent control. 

Corn blotch leaf miners tunnel into corn leaves and make a narrow streak up and down 
the leaf between the upper and lower surfaces. You will usually find a dirty-yellow 
to green maggot in the tunnel. No damage is done, and this is usually more of a 
curiosity than anything else. 

Leafhoppers are laying eggs in the tissue of corn leaves. The egg mass is usually 
fan -shaped, and each egg represents a fan rib. They will not scrape off, as corn- 
borer egg masses do. Leafhoppers are not important. 

Lady beetle adults are present in corn fields, laying their orange eggs. These 
elliptical-shaped eggs are attached upright on the corn leaf, and are layed in clus- 
ters. Lady beetles and their young eat other insects. 

Green lacewings deposit tiny white eggs individually on the stems of corn leaves. 
The young is the aphid lion, which eats aphids and other insects. 



■3- 



HOMEOWNER PROBLEMS 



Co ttony maple scale appears as a sticky, cottony mass on tree branches- -especially 
those of maple and honey locust. At present, these are the adult scales with eggs 
inside the cottony area. They are sucking plant sap from the twig. The eggs will 
be hatching in early July, and the young will crawl out onto the underside of leaves. 
These crawlers will appear as tiny, yellow specks on the leaves. They will remain 
on the leaves, sucking plant juices until September. For control, spray in early 
to mid- July with malathion. Be sure to spray the leaves near twigs covered with 
the cottony masses thoroughly. 

Mimosa webworms have begun to feed on mimosa and honey locust trees, and to construct 
web nests on the branches. Spraying with either malathion or carbaryl (Sevin) when 
the nests first appear will control this insect. A repeat treatment may be needed 
after two or three weeks. 



WEEDS 



Quite a bit of replanting has been necessary this year. Some areas are still wet, 
and there are still some fields to plant. What do you plant where atrazine was 
previously applied for corn and the field must be replanted? 

Planting soybeans would not be in accordance with the label, and the risk of severe 
injury to soybeans is considerable. Sorghum would probably tolerate the atrazine, 
but you need a market or some use for the sorghum. Sorghum- sudan may tolerate the 
latrazine, but most farmers could not use a very large acreage. Although sorghum or 
sorghum-sudan may tolerate the atrazine that was applied earlier, strict interpre- 
tation of the label suggests that this practice is not clearly approved for Illinois. 
If you can use corn silage, that would be one of your best answers. 

A short-season com to be used for grain is also a possibility. Although yields may 
not be very good and drying at harvest will probably be necessary, this may be better 
than leaving the land idle. Raising sunflowers or buckwheat is not feasible on land 
treated with atrazine. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman , and Tim Coo ley , 
College of Agriculture , University of Illinois at Urbana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: M.D. McGlamery and E.L. Knake , Department of Agronomy. 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



M/k / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



IVTE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



'OR IMMEDIATE RELEASE 



No. 15, July 10, 1970 



fh-is series of weekly bulletins provides a general look at the insect, weed, and plant 
lisease situation (fruit and commercial vegetables excepted) , along with suggested, 
ibbreviated control measures . Each individual should check his own fields to deter- 
mine local conditions. 



INSECTS 



?ORAGE 






Grasshoppers may be scattered throughout some hay fields. Where there are 17 per 
;quare yard, they eat a ton of hay a day in a 40-acre field. Three to six per square 
rard are considered enough to cause economic damage. When cutting hay, leave several 
incut swaths as traps. Spray these with 1 pound of malathion or 3/4 pound of carbaryl 
^Sevin) per acre. There is no waiting period between application and harvest. 

SOYBEANS 

Grasshoppers are present throughout some soybean fields that were grass or hay fields 
Last year. The eggs were laid in these fields then, and have now been hatching for 
ibout two weeks. You can apply carbaryl, malathion, naled (Dibrom) , or toxaphene. If 
grasshoppers are migrating from adjacent fields into beans, you can get the longest 
control with toxaphene, applied as a border spray. But do not apply toxaphene next to 
cish-bearing waters. Do not apply carbaryl near bee hives. 

Green clover worms can be found in some bean fields. They are not numerous enough now 
to create any problem, but they do bear watching in late-planted beans. Their primary 
lamage will be leaf eating. If they attack beans between the blossom and pod-fill 
stages, the damage is the same as with grasshoppers. However, these worms do die of a 
fungus infection and are found as white, dusty, mummified worms. They are also para- 
sitized by a fly that deposits white, globular eggs on the backs of the worms behind 
the head. These two natural enemies help control this pest. No insecticides are 
needed at this time. 

20RN 



Grasshoppers have not been reported in cornfields. They may migrate into them later. 
Jse the same insecticides as you would for soybeans. However, please note that diazi- 
lon now has a label for use on corn. 

Horn rootworm adults are beginning to emerge. Although only a few western and north - 
ern adults have been seen, more will be present soon. From now on, keep an eye on 
silking. If there is an average of 5 or more beetles per silk and pollination is just 
beginning, an application of carbaryl or malathion will be profitable, in order to pro- 
tect the corn during the pollinating period. Also, check the number of rootworm bee- 
tles, to have an idea of the rootworm prospects for that field in 1971. 



-2- 

Questions will soon be asked about corn leaf aphids . As yet, we have observed very 
few of them. They often appear first on grasses, then later on corn. The period of 
growth between pretassel and pollination is critical for corn. Pull 10 whorls in five 
places in the field and unroll them to see if aphids are present. If it is dry and 5C 
percent or more of the plants are infested, the use of diazinon or malathion is recom- 
mended to individuals. If aerial applications are made, parathion can be used if prop 
er protective measures are taken. Do not use parathion in seed fields that are to be 
detasselled by hand. 

SMALL GRAINS 

Cereal leaf beetle infestations are reported by the Illinois Department of Agriculture 
as much-more common than in the past. New areas of infestation will be announced wher 
survey work now underway is completed. 

LIVESTOCK 

Face flies are bothering pastured cattle in some areas. Cattle stop grazing, bunch up 
mill about, switch their tails, and rub their heads as they fight these flies. At the 
very least, cattle with lots of face flies (15 to 20 or more per animal) usually devel 
op eye problems. Face flies may also transmit pinkeye disease. For control on dairy 
cattle, apply a 2-percent, ciodrin oil-base spray at 1 to 2 ounces per animal as often 
as once a day, if needed. A 1 -percent, ciodrin water-base spray- -applied at 1 pint pe 
animal per week- -may be used in place of the oil-base spray. Dust bag treatments with 
insecticides like ciodrin or coral do give effective control of face flies. 

For pastured beef cattle, the ciodrin water-base spray (as suggested for dairy cattle) 
should be considered. Otherwise, use a head- or back-oiler, wrapped with canvas or bu- 
lap and saturated with 5-percent solution of toxaphene in oil. This will afford par- 
tial relief from face flies. Keep the oiler in good repair and well saturated. Do 
not apply toxaphene to beef cattle within 28 days of slaughter. 

HOMEOWNER PROBLEMS 

Corn earworms are much more numerous than usual in the early fields of sweet corn in 
southern and central Illinois. Homeowners may need to treat silking sweet corn with 
carbaryl (Sevin) ; and if so, will need to continue spraying the ear zone every 2 to 3 
days until the silks are brown. 

Tomato fruitworms (same as corn earworms) could be a problem in ripening tomatoes. 
These caterpillars tunnel into the tomato fruit, usually next to the stem. Spraying 
with carbaryl will provide control. There is no time limitation between the last 
spray and harvesting tomatoes or corn. 

Picnic beetles seem to be very common this year, especially as uninvited guests to 
picnics or backyard cookouts. These black beetles with four yellow spots are attracte 
to the odors of rotting fruit and vegetables, or to the smell of any food. 

For control around the home, harvest fruits and vegetables before they become overripe 
Dispose of spoiled produce. To kill the adult beetles, spray with malathion, diazinon 
or carbaryl (Sevin) in and around garbage cans. Spraying shrubbery and tall grass wit 
any of these insecticides before a cookout will greatly reduce the number of these 
beetles. 

Follow the directions on the label. Check plants that may be injured if sprayed with 
the insecticide you are using. Either 0.1-percent pyrethrin or 0.5-percent dichlorvos 



(DDVP) spray in pressurized cans will give a quick knockdown of beetles that sud- 
denly move into an area. 



ANNOUNCEMENTS 



CORN ROOTWORM DEMONSTRATIONS 



July 14, Knox County. The Ed Bowman Farm, 1.5 miles North of Oneida on the West side 
of road. Don Teel, Extension Adviser. (309) 342-5108. 

July 15, Ogle County. The Charles Mullen Farm, 1.5 miles North of Adeline on the West 
side of road. Stan Eden, Extension Adviser. (815) 732-2191. 

July 16, Boone County. The Bob Newport farm. Go East on Belvidere-Poplar Grove black- 
top, one-half mile North and East of Belvidere on the West side of road. 

July 17 , Boone County. The Ken Reeber farm, 1 mile North of Poplar Grove on blacktop, 
East side of road. Junction with the Quail Trap Road. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Tim Cooley , 
College of Agriculture, University of Illinois at Urbana-Champaign, and the Illinois 
Natural History Survey. 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



TH £ LIBRARY OF THE 

WG -6 1370 



No. 16, July 17, 1970 



U AT "URSANA,CHAMPAIGN. 



This series of weekly bulletins provides a general look at the insect, weed, and -plant 
iisease situation (fruit and commercial vegetables excepted) , along with suggested, 
abbreviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



■20RN 

Corn leaf aphids are numerous in some fields; they may seem to almost "explode" within 
the next two weeks, but this will vary greatly from hybrid to hybrid and from area to 
area. Limited surveys indicate the possibility of a serious problem; but, as yet, we 
cannot define any problem areas. The number of aphid predators is low, which will 
permit a faster buildup; but a disease is killing some aphids. Also, high temperatures 
have slowed reproduction. 

Corn in the late-whorl and early tassel stages seems to have the most aphids. Early 
fields in which pollination is already occurring will escape damage. Corn injury us- 
ually takes place between the pretassel and pollinating stage. Aphids suck the juices 
from plants, causing stunting. With heavy infestations and stress conditions (partic- 
ularly dryness), the plants will be barren, or at best produce a shrivelled ear. 

Early treatment is best. Treatments should be made prior to brown silks. Many fields 
are in the late-whorl stage or are just now coming into tassel, and should be checked. 

Do not panic. Do not spray unless it is justified. Examine all fields carefully. If 
50 percent or more of the plants are lightly to moderately infested with aphids, the use 
of 1 pound of malathion or diazinon, or 1/4 pound of methyl parathion, per acre as a 
spray will be effective. 

For best results, the spray should be applied just after the tassels begin to show. 
\llow 5 days for malathion, 10 days for diazinon, and 12 days for methyl parathion 
Detween treatment and harvest for grain, ensilage, or stover. Methyl parathion should 
oe applied only by experienced applicators . 

If corn is in the late-whorl stage, 1 pound of either diazinon or phorate (Thimet) as 
granules will be effective. Do not use phorate or parathion in seed fields that are 
to be detasselled by hand. 

Picnic beetles are present in corn whorls in many areas. They are of little concern 
in field corn. But in sweet corn, they are getting into the ears and destroying the 
kernels . 



Infestations of second- generation corn borers on late-maturing corn could be severe in 
the southern section of Illinois. Moth- emergence is underway, and peak egg-laying can 
be expected by about July 25 in that area. Some borers are present in most of the com 
fields that were planted early, and the emerging moths will move to the late-maturing 
fields that are in the late-whorl to early silk stage to lay their eggs. Check these 
late-maturing fields during late July or early August for corn-borer egg masses or 
whorl feeding. 

First-generation borers are pupating rapidly in the central section, and an occasional 
second- generation moth has emerged. Pupation is just getting underway in the northern 
section. 

For corn in whorl stage, if 75 percent or more of the plants are showing recent whorl 
feeding, apply carbaryl (Sevin) or diazinon granules. If the corn has tasselled, look 
for egg masses. If the average is 1 or more per plant, apply an insecticide after a 
few eggs have hatched. 

Commercial applicators may prefer to use parathion at 1/2 pound per acre. Sprays by 
air or high-clearance equipment are effective on tasselled corn. Allow 10 days between 
treatment and harvest for diazinon and 12 days for parathion. Carbaryl has no waiting 
period. 

SMALL GRAINS 

Cereal- leaf -beetle quarantines have been imposed on the following, entire counties: 
Champaign, Christian, Clark, Coles, Cook, Cumberland, DeWitt, Douglas, DuPage, Edgar, 
Fayette, Ford, Grundy, Iroquois, Kankakee, Livingston, Macon, McLean, Montgomery, 
Moultrie, Piatt, Shelby, Vermillion, and Will. A quarantine is in effect for parts of 
these counties: North of a line along the north edge of Township 6 in Effingham; Grove 
Township in Jasper; Seward Township in Kendall; Road District No. 2 in Menard; East of 
a line along the East edge of Range 6, West in Sangamon; and Kansas Township in Woodfor* 
County. Continued surveys may reveal new infested areas; if so, these will be announce' 

For further information on cereal- leaf -beetle quarantine and regulations, contact 
Mr. Rodney Anderson, Head, Division of Plant Industries, State Department of Agriculturi 
Emerson Building, State Fairgrounds, Springfield, Illinois 62706; Mr. Burhl McClung, 
Supervisor in Charge, Plant Protection Division, USDA, P.O. Box 98, Urbana, Illi- 
nois 61801; or R.M. Puyear, District Supervisor, Plant Protection Division, USDA Box F, 
Wyanett, Illinois 61379. 

GENERAL 

Grasshoppers continue to pose a threat in many areas. Hot, dry weather increases the 
likelihood of damage. They will tend to move to the more-succlent crops such as corn 
and soybeans as the vegetation dries out in roadside, ditchbank, fencerow, waterway, 
and hayf ield areas . 

For control in roadsides, ditch banks, fencerows, waterways, and other grassy areas 
(where no crops are involved) , apply toxaphene at 1-1/2 pounds per acre. Do not apply 
it near fish-bearing waters. 

For control in clover, alfalfa, and hayfields , apply 3/4 pound of carbaryl or 1 pound 
of malathion per acre. Do not apply to clover or alfalfa fields that are in bloom, sine 
both insecticides are toxic to bees. 



For control in corn and soybeans , apply carbaryl at 3/4 pound or toxaphene at 1-1/2 
pounds per acre. Do not feed toxaphene- treated corn or soybeans as a forage to dairy 
cattle or to livestock being fattened for slaughter. Do not harvest soybeans as grain 
for 21 days after treatment with toxaphene. Carbaryl has no waiting period or other 
restrictions when used as directed. 

LIVESTOCK 

Under "Face Flies" in last week's bulletin (No. 10), the statement "Dust bag treatments 
with insecticides like ciodrin or Coral do give effective control of face flies" should 
have read "Dust bag treatments with insecticides like ciodrin or Coral do not give ef- 
fective control of face flies." 

HOMEOWNER PROBLEMS 

Picnic beetles continue to plague home vegetable gardeners. They are damaging the ker- 
nels of ripening sweet corn. They will swarm to overripe vegetables or fruit. 

To help reduce the problem, pick fruits and vegetables before they become overripe. 
For control on sweet corn, apply carbaryl (Sevin) as a spray 'to the ear zone and leaf 
axils. To mix, use 2 tablespoons of the 50-percent wettable powder per gallon of water. 
Do not expect to control the beetles that are deep in the silks; the insecticide will 
not reach them. 

Additional treatments every 4 or 5 days may be needed to prevent further infestations. 
This treatment will also help prevent infestations by corn earworms and corn borers. 
Carbaryl or malathion may be used on other vegetables or fruits if picnic beetles pre- 
sent a problem. Follow the directions on the label for dosage, waiting period, and 
other restrictions. 



WEEDS 
2,4-D, POSTEMERGENCE IN CORN 

Weeds are still bad news in some fields where adequate cultivation and spraying have 
not been possible. 2,4-D is about the only spray to consider for corn at this late 
date. 

Most 2,4-D labels say, "Do not apply from tasseling to dough stage." This statement is 
apparently based on early research which showed that spraying at certain critical stages 
might interfere with development of grain. In one Iowa study, 2,4-D was sprayed on 
corn plants at various stages. Applying 2,4-D when tassels were beginning to emerge 
resulted in inhibition of ear shoots. And application of 2,4-D 1 to 4 days before silk 
emergence caused severe inhibition of seed set on the developing ear. 

Each year, 2,4-D causes some brittleness and breakage of corn, some onion- leafing, and 
some malformation of brace roots. But we have had very few reports from farmers' fields 
of 2,4-D affecting ear and grain development. Perhaps this is partly because of pre- 
cautions to avoid spraying during the critical period, more resistant hybrids, and mini- 
mals amounts of 2,4-D applied directly to the corn leaves. 

But it still seems safest to avoid spraying during the critical stages, especially dur- 
ing early development of the ear shoots (this is about the time tassels begin to emerge) 
and just before silks emerge. 



Silks are usually pollinated very soon after they emerge. After fertilization and when 
the silks are drying, there is apparently less risk of injury from 2,4-D. However, 
fertilization is followed by a period of rapid nutrient uptake and movement of food 
materials to the grain. Stress conditions or injury of various kinds during this stage 
may interfere with normal kernel development. 

Although weeds will usually be large, "tough," and harder to kill with 2,4-D, spraying 
can be resumed after the grain is well on its way and in the dough stage . The dough 
stage begins about 5-1/2 weeks after silks begin to emerge. During the dough stage, 
the silks are dry, kernels are still developing, and starch is accumulating. 

But remember that by the time corn reaches the dough stage, many weeds already will have 
done most of their damage through competition for nutrients and moisture. Many weed 
seeds will also be developed sufficiently to be viable. However, the late spraying may 
make harvesting a little easier. 

2,4-D AND CORN INJURY 

Quite a bit of corn was injured by 2,4-D this year. Some that was sprayed before the 
winds of June 16-17, was lodging because it lacked brace roots and because of stalk 
brittleness. 2,4-D injury occurs every year, but it appears to be more common during 
Seasons of highly variable weather where we have cold-wet spells followed by very warm 
weather. Some corn hybrids are more susceptible than others. 

Some of the precautions with 2,4-D are: 

1. Be sure and use the proper rate. The rate varies with formulation and type, 
the standard formulation now is 4 pounds per gallon, but there are still some 
2-pound-per-gallon and other formulations. It requires less of the ester type 
of 2,4-D than of the amino form. 



? 



Use drop nozzles if corn is more than 8 to 12 inches tall. If drop nozzles are 
directed into the row, Use proportionately less material. Directed application 
is not the broadcast rate on the corn. 

5. Check nozzles for proper gallonage, and calibrate the sprayer. You may have the 
right proportions in the sprayer, but if you put too much volume (gallonage) , you 
will have too high a rate. 

4. Do not spray corn after tasselling, the work is No-No from tassel to soft dough. 

FENCE-RON WEED CONTROL 

Xow is the time to push weed control in fencerows. Dalapon (Dowpon) can be used to 
control grasses and prevent seed production. You can add 2,4-D to control the broad- 
leaved weeds . 

WEEDS IN SMALL GRAIN STUBBLE 

With the small grain harvested, weeds such as foxtail and ragweed now have a chance for 
more- vigorous growth. If you don't plan to work the fields for a while, consider clip- 
ping or spraying to reduce the production of weed seeds. If you don't have a grass or 
legume seeding, consider spraying. A low-cost application of 2,4-D can check most broad- 
leaved weeds. A few pounds of dalapon (Dowpon) per acre- -alone or added to 2,4-D- -can 
reduce the seed production of grasses considerably. The smaller the grass, the less 
dalapon you'll need. If weeds have made much growth, it may pay to clip or chop the 
stubble before spraying. 



If you have Johnsongrass in wheat stubble and plan to plant corn or soybeans in the 
field next spring , cons ider a dalapon application now for control. Clipping or chop- 
ping the Johnsongrass a time or two before spraying will help deplete the food reserves 
in roots and rhizomes; this generally improves control. 

When the Johnsongrass is about a foot high and is actively growing during warm moist 
weather, spray with 8 pounds of dalapon in 50 to 40 gallons of water per acre. Wait 
at least a week or two before working the soil, in order to give the Dowpon plenty of 
time to translocate and act on the roots and rhizomes. Unless the Johnsongrass is 
making good, active growth when sprayed, results may be disappointing. 

By spraying Johnsongrass this summer, you can control much of the old Johnsongrass 
without delaying planting next spring. But you should plan to follow up next spring 
with a preemergence application of Eptam for corn or Tref Ian for soybeans , to control 
Johnsongrass that may come from seed. See Illinois Circular 827 for more details on 
Johnsongrass control. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Cooley , 
College of Agriculture, University of Illinois at Urbana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: M.D. McGlamery and E.L. Knake , Department of Agronomy. 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



■ > '•• / 




COLLEGE OF 
AGRICULTURE 

UM\ E^Si^ O- 
ILLINOIS AT 
URBAMA -CHAMPAIGN 
AND NATURAL 

HISTORY SURVEY 

URBAMA ILLINOIS 




v]SECT.\YEED& PLANT DISEASE SURVEY BULLETIN 



TE COUNTY LOCAL GROUPS U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASI 



No. 17, July 24, 1970 



This series ;; :v= : :!: bulletins provides a general loo~k at the insect, weed, and -plant 

disease situaticr, fv:-.:r tti .v~:-Ytt ' v vegetables excepted . along with suggested, 

breviated contro'i measures. Each individual s : :::-.'.i jheck his own fields to determine 
local conditions. 









oofs 






Corn leaf aphid populations in general did not increase as much as expected during the 
past week, although they are causing problems in occasional fields. Furthermore, popu- 
lations in some fields apparently began to decrease, and dead aphids can be found in 
unemerged tassels. 






Infestations are generally low or non-existent in fields already in full tassel, pres- 
ent in very small numbers in fields in early tassel, and noticeably present in some 
fields in the pretassel or late-whorl stage cd growth. However, only about 1 of 
every 10 or 20 of these fields has enough aphids to pose a potential problem. 

Examine fields not yet in tassel t--.refv.llv every 5 days until after tassel emergence. 
Tear open the whorls of 5 to 10 plants in each of 4 or 5 places in the field. If 50 
percent or more of the plants are moderately infested with aphids . apply 1 pound of 
malathion or diatir.tr. or 1 4 pound of methyl parathion per acre as a spray. Apply 
just after the tassels begin tc show. Allow 5 days for malathion, 10 days for diazinon, 
and Id days fox methyl parathion between treatment and harvest for grain, ensilage, or 
stover. Methyl parathion should be applied only by experienced applicators. 

Tht res are ratter cus ir. ccrr. whorls. Dc not confuse them, -..-.t '-. the green aphids that 
move about very slowly. Thrips are trim insects that move very rapidly and are black, 
yellow, or orange. Nc centre 1 is 



IpanA/" 



Grasshcrrers can now be found in cornfields. If they are abundant and devouring leaves, 
ears mav be smaller titan normal. If they feed em silks, the-." can affect pollination if 

emplete. 



it is met 



To control, apply carbaryl Aevin] , diactrc:.. malathion, er texarheme. dther insec- 
ticides may do* the ; e'e . he met arm A - texarheme te eerm te he used for ensilage or 

tedder. 



Picnic "eeetl 



the elack beetles with the 4 Drange er yellow specs, are abundant in 
seme ce:ttfields . Usually they feed in decaying organic matter er possibly teller.. When 
they gc te the silks, thev de not affect pollination te any decree, but they met.- em 



-2- 

occasion in field corn get down to the tip of the ear where they can puncture a few 
kernels of corn. Most importantly this silk and kernel-tip feeding can open up the 
ear for decay later. They are more common in loose-husk hybrids. We do not usually 
recommend control. After the beetles are down in the silks, they are difficult to 
reach with chemicals . 

Northern and western corn rootworm development is slightly ahead of 1969. Adults are 
emerging in abundance in northern and central Illinois and will continue to emerge 
from the soil for another 3 to 4 weeks. Pupation of larvae is progressing rapidly in 
many fields. Pollination damage by adults may occur in late-maturing corn since they 
tend to migrate to these fields to feed on fresh pollen and silks. 

Check the silks for the presence of tan or green northern corn rootworms and the 
yellow- and black-striped western corn rootworm adults. Treatment is justified if 
there is an average of 5 or more beetles per silk and less than 50 percent of the plant 
have silked. Sprays of carbaryl (Sevin) , malathion, or diazinon at 1 pound of actual 
chemical per acre or 1/4 pound of methyl parathion per acre are effective. Methyl para 
thion should be used by experienced applicators only. Allow 5 days between treatment 
and harvest for malathion, 10 days for diazinon, and 12 days for methyl parathion. Car- 
baryl has no waiting period. 

Rootworm infestations in the demonstration plots conducted by extension advisers in 
Boone, Mercer, Knox, Ogle, and Woodford counties, this year were generally higher than 
in past years . Larval counts averaged 20 to 40 worms per plant in some of the untreate 
plots and extensive lodging was evident. If moisture is plentiful, the damaged plants 
will partially recover, but without moisture damage may be severe. Goosenecking and 
lodging of plants as a result of larval feeding are quite evident in some fields . 

Make a note of the fields with lodging and adult rootworms, since these fields may have 
a recurring problem in 1971. Also, notify your county extension adviser if you have ha 
failures with one of the organic phosphate or carbamate insecticides used for resistant 
corn rootworms . 

;cond- generation European corn borer moth emergence is nearing completion in the south; 
ern section of Illinois, and egg- laying by moths is beginning in some fields in the 
late-whorl to early-silk stage. Peak egg-laying can be expected about July 25 in that 
area. Check these fields for egg masses and whorl feeding since the second- generation 
moths prefer these fields to deposit their eggs in. For corn in the whorl stage, if 75 
percent or more of the plants are showing recent whorl feeding, apply carbaryl (Sevin) 
or diazinon granules. If the corn has tasselled, look for egg masses. If the average 
1 or more egg masses per plant, apply an insecticide after a few eggs have hatched. 
Aerial sprays on tasselled corn are effective, but on whorl-stage corn, aerial applica- 

;ions should be granules, not sprays. Use 1-1/2 pounds of carbaryl (Sevin), or 1 pound 
of diazinon, or 1/2 pound of parathion per acre. Allow 10 days between application and 

ilage removal for diazinon and 12 days for parathion. Parathion should be applied 
only by experienced applicators. No waiting period is required for carbaryl. 

In central sections, borers are pupating rapidly, and moth emergence is about one-third 
completed. An occasional moth has emerged in the northern section and pupation is 
underway . 

Woolly bears and cattail caterpillars (brown, orange-striped, and bristly) are present 
in cornfields. The woolly bears like to feed on silks, the cattail caterpillar on 
leaves. Insecticide control is seldom needed. 



Black cutworm damage is still occurring in a few late-planted cornfields. Insecti- 
cide control may be warranted in these fields to prevent further stand reduction, 
since replanting is no longer feasible. 

LIVESTOCK 

Face flies have continued to increase and dairy and beef cattle in some areas are 
suffering from these high infestations. Eye problems are apparent in cattle where 
large numbers are found. Counts last week averaged 20 face flies or more per animal, 
the highest observed since 1962. Cattle plagued by face flies usually develop eye 
problems such as pink eye, which is transmitted by this pest. For control on dairy 
cattle, apply a 2-percent, ciodrin oil-base spray at 1 to 2 ounces per animal as often 
as once a day, if needed. A 1-percent, ciodrin water-base spray- -applied at 1 pint 
per animal per week- -may be used in place of the oil-base spray. Dust bag treatments 
with insecticides like ciodrin or coral do not give effective control of face flies . 

For pastured beef cattle, the ciodrin water-base spray (as suggested for dairy cattle) 
should be considered. Otherwise, use a head- or back-oiler, wrapped with canvas or 
burlap and saturated with a 5-percent solution of toxaphene in oil. This will afford 
partial relief from face flies. Keep the oiler in good repair and well saturated. Do 
not apply toxaphene to beef cattle within 28 days of slaughter. 

HOMEOWNER INSECT PROBLEMS 

Sod webworm moths are beginning to appear in increasing numbers, particularly in 
southern and central sections. These buff-colored moths rest in shrubbery and tall 
grass during the day and are seen flying in a zigzag pattern over the lawn near dusk. 
These are the second- generation moths that are laying their eggs at this time. If 
you find large numbers of these moths in your yard, plan to treat your lawn with an 
insecticide about 2 weeks later. Usually target dates for treatment are late July in 
southern sections, early to mid-August in the central section, and mid- to late Aug- 
ust in the northern sections. 

The larvae of the webworm are gray worms with brown spots and black heads. They are 
about an inch long when full grown and live for 3 to 4 weeks in the worm stage. The 
worms live in silken- lined burrows in the thatch of the lawn, clipping off grass blades 
at the base. Brown spots appear in the lawn and large numbers of robins will move in 
to feed on the larvae. By this time, it is usually too late for control. 

For control of webworms, apply a spray or granules of 2 pounds of actual carbaryl 
(Sevin) , 1 pound of actual diazinon, or 1-1/4 pounds of actual trichlorfon (Dylox) per 
10,000 square feet. Use about 25 gallons of water to distribute the insecticide over 
the 10,000 square feet when spraying. Do not water the lawn for at least 5 days after 
treatment. If heavy rains occur within 3 days of application, a repeat treatment may 
be needed. 



WEEDS 
TOMATOES, GRAPES, AND 2,4-D 



Tomatoes have started ripening. And we have already seen the first samples of tomatoes 
and grapes injured by 2,4-D. Tomatoes and grapes are two of the most sensitive plants 
as far as foliar (leaf) symptoms . The leaves wrinkle and elongate into grotesque 
shapes . 



Can you still eat the tomatoes or grapes if they have been injured by 2,4-D? The 
answer is "yes," if the fruits are still normal, even though the leaves are injured. 
A tiny amount of 2,4-D is enough to cause foliar damage, but larger amounts are re- 
quired to injure the fruit. The amount necessary to injure a human consumer is much 
greater. 

But be a good neighbor, don't spray 2,4-D esters --especially high-volatile ester- - 
near a man's vineyard or home garden. 

MARIHUANA 

Marihuana is now classified as a noxious weed in Illinois. It is against the law foi 
landowners to have it growing on their property. If landowners take this obligation 
seriously, we will have fewer pickers going to pot in Illinois. 

Our slogan is "Swat Pot." Early control is most effective, but better late than neve 
Some plants are already producing seed. Pulling, mowing, or tillage is still an ef 
fective way to prevent further seed production. 

Based on earlier research this year, 2,4-D ester, 2,4,5-T, silvex, Banvel, and amitro 
T were effective and probably would still be helpful if applied soon. Although 2,4-D 
can be effective if applied early, 2,4,5-T is a better choice now on the tougher plan 

Do not use 2,4,5-T around homes or on lakes, ponds, and ditch banks. Silvex does not 
have these restrictions and may be slightly more effective than 2,4,5-T on marihuana.; 
Banvel has been effective, but be careful to avoid injury to nearby susceptible plant 

If you use 2,4-D, 2,4,5-T, silvex, or Banvel use about 1 pound per acre. Amitrole-T ' 
looked good earlier at a rate of 2 to 4 pounds [1 "to 2 gallon) per acre. Tordon give 
good control of marihuana, but risk of injury from drift or soil residue to soybeans 
or other susceptible plants discourages its use in many areas . 

i 

SOYBEANS 

* 

A lot of soybean fields look quite clean this year. The delayed planting, use of 
herbicides, rotary -hoeing, and good cultivation have all contributed. 

Now is a good time to chop that volunteer corn out of soybeans . Relatively few field 
have a serious problem. 

As the beans stop growing, some of the taller-growing weeds (like velvet- leaf) will 
become more evident. Pulling these to prevent seed production will be well worth- 
while in many fields. Pulling may not sound very "glamorous," but is still practical 
and economical in many fields. (And it will give the kids something to tell their 
grandchildren.) 

READ THE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , Collet 
of Agriculture, University of Illinois at Urbana-Champaign , and the Illinois Natural 
History Survey, 

WEEDS: M.D. McGlamery and E.L. Knake , Department of Agronomy. 

AG COMMUNICATIONS: Del Dahl . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



ink 2 



Ji 1 



./v. 



COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



rATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



OR IMMEDIATE RELEASE 



No. 19, August 7, 1970 



Fhis series of weekly bulletins provides a general look at the insect, weed, and plant 
iisease situation (fruit and commercial vegetables excepted) , along with, suggested, 
xbbreviated control measures. Each individual should check his own fields to deter- 
mine local conditions. 



INSECTS 






VRN 



■ 



: all armyworms are damaging late -maturing corn, particularly in the southern sections, 
fhese dark-brown-to-gray to dull-green, smooth- skinned worms feed in the whorl, giving 
)lants a ragged appearance as the leaves emerge. A series of plants in a row will 
;how damage, and these patches of infested plants will usually be over the entire 
field. The worms this week were one-third to one-half grown with another 7 to 10 days 
)f feeding time left before they mature. Additional generations could still present 
further problems in late-maturing fields. After corn has pollinated, fall armyworms 
/ill attack the developing ears (like earworms), and some larvae will be present in 
;ars until frost. 

'reatment is justified in fields in which 20 percent or more of the plants are in- 
fested. Before applying insecticides be sure the worms are still present and that 
,ost of them are not more than 1-1/4 inches long. When they reach about 1-1/2 inches, 
hey are mature; at that size they stop feeding, drop to the ground, enter the soil, 
nd pupate. 

or control, apply either carbaryl (Sevinj or toxaphene at 1-1/2 pounds of chemical 
er acre. Granules are preferred, especially if air applications are made. Ground 
pplications with the spray directed into the whorl will provide fair to good results, 
epending on the size of the worms. The larger worms that are deep in the whorl are 
ore difficult to reach with an insecticide, and control is poor. Smaller worms, 
any of which are on exposed leaves, are readily killed. 

o not feed toxaphene -treated corn as forage to dairy cattle. Do not feed toxaphene- 
reated corn as silage to livestock fattening for slaughter. Corn treated with toxa- 
hene granules may be fed as stover to beef cattle to within 28 days of slaughter, 
here are no restrictions for carbarvl. 



econd-generation flea beetles are numerous in corn, particularly in southern Illinois. 
;iese shiny-black beetles (slightly larger than a pinhead) that jump when disturbed 
3ave white scratch marks on the leaves. Some extremely late fields of corn (8 to 12 
iches high) are being damaged by these insects. The beetles can also be found feeding 
; i more mature corn, but the damage is not serious and no control is needed. Carbaryl 



-2- 

(Sevin) at 5/4 pound or toxaphene at 1-1/2 pounds of actual chemical per acre sprayed 
over the row will control them. Do not feed corn treated with toxaphene as ensilage 
or stover to livestock. 

Corn leaf aphids are heavy in some fields in east-southeast Illinois and in occasional 
fields in other areas. Fields in pretassel have the most aphids. In general, corn 
leaf aphid populations are light, and in many fields the population has decreased as 
tassels emerged. A widespread outbreak of these aphids is not expected this year. 
However, there will continue to be occasional fields where aphids build up to damaging 
numbers . 

In pretassel fields, if 50 percent or more of the plants have moderate numbers of 
aphids, treatment is justified. Apply the treatment just after tassels begin to show. 
In more mature fields, if 15 to 20 percent or more of the plants are heavily loaded 
with aphids (top third blackened) and the corn is under stress, treatment is also 
profitable. 

For control, apply 1 pound of malathion or diazinon or 1/4 pound of methyl parathion 
per acre as a spray. Allow 5 days for malathion, 10 days for diazinon, and 12 days 
for methyl parathion between treatment and harvest for grain, ensilage, or stover. 
Methyl parathion should be applied by experienced applicators. 

European corn borer moths are laying eggs on late-maturing corn. Egg-laying will 
continue in southern Illinois for another week or two; in central Illinois for another 
2 to 5 weeks and in northern Illinois for another 5 to 4 weeks. In southern and south- 
central sections, a third generation in late August and early September is likely. 
The moths will tend to concentrate their egg-laying in fields in the late-whorl to 
early-silk stage. 

If corn is in the whorl stage and if 75 percent or more of the plants are showing 
recent whorl feeding, apply carbaryl (Sevin) or diazinon granules. If the corn has 
tasselled, look for egg masses. If the average is 1 or more egg masses per plant, 
apply an insecticide. Aerial sprays on tasselled corn are effective, but on whorl- 
stage corn, aerial applications should be granules--not sprays. Use 1-1/2 pounds of 
carbaryl (Sevin), 1 pound of diazinon, or 1/2 pound of parathion per acre. (Allow 
10 days for diazinon and 12 days for parathion between application and silage removal.) 
Parathion should be applied only by experienced applicators. No waiting period is 
required for carbaryl. 

Grasshoppers continue heavy in some areas, and migrations into corn and soybeans 
are occurring. For control, use either 3/4 pound of carbaryl (Sevin) or 1-1/2 pounds 
of toxaphene per acre. Do not apply toxaphene to corn or soybeans to be used as 
forage for livestock. Do not apply toxaphene near fish-bearing waters or carbaryl 
near bee yards. 

STORED GRAIN INSECTS 

Heavy infestations of Indian meal moth were observed in untreated wheat this week in 
southern Illinois. No meal moths were as yet present in wheat treated with malathion 
as a dust or spray. The Indian meal moth larva, which is yellow and about 3/8 inch 
long, webs several kernels of wheat together. These clumps of webbed kernels can be 
found on the surface of the grain or clinging to the side walls of the bin. The 
larva transforms to a brown, torpedo -shaped pupa (1/4 inch) from which the small 
copper -colored moth emerges. Small moths flying over the surfaces are also a sign of 
infestation. 



For control, use a grade of malathion labeled for use on stored grains. If a dust 
is used, apply 15 pounds of the 1.0-percent dust per 500 square feet of surface. If 
a spray is used, mix 5 ounces of the malathion liquid concentrate in a gallon of water 
and apply 1 gallon of this mixture per 500 square feet. In addition, spray the walls 
and ceiling of the bin above the grain. A fumigant-type insecticide will kill the 
meal moths both on and in the wheat, but a fumigant does not prevent reinfestation. 

HOMEOWNER INSECT PROBLEMS 

Here is some good advice, slightly adapted, from the Purdue University Insect Newsletter. 
Large numbers of insects can be seen on warm evenings, swarming around lights. These 
insects find their way into homes and buildings, making a general nuisance of them- 
selves. Insecticides are of little help, since within a few minutes after applying a 
quick-knockdown space spray, there are more insects back at the light. You can help 
lessen the problem by the type of lighting you use. Avoid strong, direct, white 
lighting. Indirect or more subdued lighting is preferable. Indoor lights that shine 
directly out of an opening should also be avoided. Colored walls that do not reflect 
light are preferable to glossy white. Where possible, use yellow bulbs. Also a 
bright light set in a tree, on a pole, or corner of a building some distance from 
doors and windows will attract most of the insects and help lessen the number that 
enter the building. 

Leafhoppers attracted to lights have been particularly annoying recently. These are 
wedge-shaped green insects found by the hundreds at lights. 

Second-generation sod webworm moths have been emerging and laying eggs in lawns. This 
egg-laying will continue for several more weeks. Apply ample fertilizer and water to 
the lawn to help lessen the possibility of serious damage by these insects. Once 
started, this program must be continued to avoid serious damage. If needed, an 
application of carbaryl (Sevin) or diazinon as a spray or granules will effectively 
control the worms for a week or two. A good time to apply the treatment is about two 
weeks after a heavy moth flight. An additional treatment may be needed if egg-laying 
continues heavy into late August. 

Millipedes are moving into homes from shrubbery beds, lawns, storm sewers, and nearby 
wasteland with a heavy trash cover. These migrations are somewhat earlier than normal 
(August and September) this year. It is usually the cool weather that causes them to 
seek shelter in homes. These brown or gray, hard-shelled, slow-moving, wormlike animals 
have two legs per body segment. They are sometimes called "thousand- leggers," and will 
curl up in a tight coil when disturbed. Although harmless, they make a general nuisance 
of themselves in the home, clustering in basements and garages. 

In cases of heavy- migrations, spray lawns and shrubbery beds with carbaryl (Sevin), 
diazinon, or trichlorfon (Dylox) . This provides a barrier zone in which the millipedes 
are killed, and prevents them from gaining access to the house. If migrations persist, 
repeat the treatment in a week or two. For minor problems, spray shrubbery beds and 
a 3- to 4-foot wide area around the foundation of the house for control. The general 
lawn treatment will also control sod webworms and leafhoppers , but it is ineffective 
against grubs. 



PLANT DISEASES 



LEAF BLIGHTS THREATEN CORN CROP 



Three corn leaf blights --northern, southern, and yellow leaf blight- -now threaten the 
Illinois corn crop. All three blights are caused by fungi that infect the leaves when 



-4- 

free moisture is present as rain, irrigation water, or dew. Where leaf blights are 
severe, corn ears may be immature and chaffy, feed value of fodder is lowered, and 
plants are predisposed to stalk rot. 

If leaf blights appear before or soon after tasseling, the yield, grain quality, and 
feed value will be reduced. It will be at least three weeks before losses can be 
evaluated. If the weather turns hot and dry, the spread of blights will be checked. 
All three blights usually attack the older leaves first before moving to the upper 
leaves. Heavily infected leaves turn brown and die. 

Northern leaf blight is recognized by long, elliptical, grayish-green to tan spots on 
the leaves, up to 1-1/2 inches wide and 6 inches long. Ears are not infected, although 
lesions may form on the husks. Northern leaf blight can now be found throughout 
Illinois, but the buildup to date has been light. 

Yellow leaf blight is a new disease, occurring primarily in the northern part of the 
Corn Belt. It can now be found in Illinois in scattered locations as far south as 
the St. Louis area. It is favored by cool, wet weather and should not be a factor 
until later this fall. Yellow leaf blight lesions are oval to elliptical in shape 
and tan to cream in color, averaging about 1/2 inch long and 1/8 inch wide. Sometimes 
a distinct yellow margin surrounds each spot. Yellow leaf blight lesions are very 
similar to those of southern leaf blight (see below) . The two diseases can be 
distinguished by putting pieces of infected leaves overnight in a tight plastic 
bag with a moist paper towel. If yellow leaf blight is present, small black specks 
(pycnidia) of the causal fungus appear scattered in the dead spots. 

Yellow leaf blight is closely associated with hybrids having Texas male-sterility 
(Tms) , a character commonly used by the seed trade as a means of avoiding mechanical 
detasseling. Tms brings susceptibility into inbreds and hybrids even though the 
standard versions are more or less resistant. 

Southern leaf blight is an old disease that until 1969 was considered minor. A new 
race of the causal fungus has developed to which inbreds and hybrids having Tms are 
very susceptible. It is potentially the most serious disease of Illinois corn this 
year. Lesions on the leaves range up to 1/2 inch wide and 1-1/2 inches long, being 
oblong, parallel-sided, and grayish-tan to tan in color, surrounded by a yellow zone. 
Many lesions have dark brown to purplish margins. 

The new race of southern leaf blight is causing lesions up to 6 inches long on the 
stalks and ear husks, especially in seed production fields. Lesions penetrate the 
husks and are now causing a powdery, charcoal-like rot of the ears in seed-producing 
fields. Infection is widespread but less destructive in commercial dent corn hybrid 
fields. Southern leaf blight is extremely destructive to corn throughout the south- 
eastern states and can now be found in Illinois as far north as Chicago. It is most 
widespread and damaging at present in southern and central Illinois. 

All three leaf blights are best controlled by growing resistant hybrids. Many inbreds 
and hybrids are available that resist northern corn leaf blight. Illinois scientists 
have found other types of male-sterile cytoplasm resistant to the fungi causing 
southern leaf blight and yellow leaf blight. 

Seed treatment and crop rotation are not effective control measures because the spores 
of the northern and southern corn leaf blighting fungi can be carried a number of 
miles by wind currents. 



Some major seed corn companies are now spraying their seed production fields by 
lirplane on a regular 7- to 10-day schedule, using 2 pounds per acre of a maneb or 
naneb plus zinc ion fungicide. Spraying is not recommended, however, for com- . 
nercial hybrid fields because of the cost. 

]orn planted in rotation and continuous corn on clean-plowed ground have been infected 
Less by leaf blights. Good soil preparation, proper fertility, and drainage should be 
practiced, for stress factors are known to increase severity of yellow leaf blight, 
fellow leaf blight may be controlled by the same fungicides used to check northern 
md southern leaf blights, though control is generally not practiced except by seed 
producers . 

]apsule summary : Leaf blights can now be found in practically all corn fields in 
Qlmois. How severe these blights become will be determined largely by weather 
zonditions during the next several weeks. 



SPECIAL NOTE TO COUNTY EXTENSION ADVISERS 



Ve now have a supply of self-addressed franked mailing tubes for use in sending us 
Insect specimens. If you are in need of a supply of these mailing tubes, please let 
as know. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Tim Cooley , College 

of Agriculture, University of Illinois at Urbana-Champaign , and the Illinois Natural 
History Survey. 

PLANT DISEASES: E.E. Burns and M.C. Shurtleff , Department of Plant Pathology . 
\G COMMUNICATIONS: Del Dahl . 

[he information for this report was gathered by these people, staff members, county 
extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



t ' A^ 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



TATE/COUNTV/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 















FOR IMMEDIATE RELEASE 



No. 20, August 14, 1970 



This is the last in this series of weekly bulletins. We have tried to provide a gen- 
eral look at the insect, weed, and plant disease situation (fruit and commercial 
vegetables excepted) , along with suggested, abbreviated control measures . Each in- 
dividual should check his own fields to determine local conditions. 



INSECTS 



GENERAL 

Grasshoppers are feeding on a variety of crops such as tomatoes, corn, soybeans, hay 
crops, and many flowers. In fact they will eat most anything that is green if they 
are hungry. They have been and still are migrating from fence rows, ditch banks, and 
other areas. As hay is cut, they migrate from hay fields. Malathion or carbaryl 
(Sevin) are two commonly used garden and flower insecticides that will control them. 
These along with naled (Dibrom) and toxaphene can be used on soybeans. These four 
insecticides and diazinon can be used on corn. Check the label for length of time re- 
quired between application and harvest. Do not use toxaphene on forage to be fed to 
dairy cattle or livestock fattening for slaughter. 

CORN 



Fall armyworms continue to damage late-maturing corn. These gray to dull-green to 
dark-brown smooth- skinned worms feed deep in the whorl. Damaged leaves have a ragged 
appearance. In some fields, fall armyworms are entering ears. Many of the worms are 
now mature (1-1/2 inches) or soon will be. At maturity they stop feeding, drop to the 
ground, and pupate in the soil. 

Control is difficult, especially with the larger worms that are deep in the whorl or 
ear. For best results on whorl -stage corn, use granules of either carbaryl (Sevin) 
or toxaphene at 1-1/2 pounds per acre. Sprays on whorl-stage corn provide erratic 
results. If a spray is used, place the nozzles over the row and direct the spray into 
the whorl. On tasselled corn, sprays should be directed at the ear zone and upper one- 
third of the plant . 

■ 
Do not feed toxaphene -treated corn as forage to dairy cattle. Do not feed toxaphene - 
treated corn as silage to livestock fattening for slaughter. Corn treated with 
toxaphene granules may be fed as stover to beef cattle to within 28 days of slaughter. 
There are no restrictions for carbaryl . 

Rootworm beetles are abundant in some fields. If the corn is less than 50 percent 
silked, an insecticide will help prevent pollination injury. Use carbaryl (Sevin), 
diazinon, or malathion. Carbaryl is harmful to bees and although effective on 
beetles, should not be used if bees are frequenting the tassels for pollen. In this 
';ase, use diazinon or malathion late in the day. 



-2- 

Most importantly, from now on watch for beetles in silks, ear tips, and plants. If 
you find an average of 2 or 3 per plant, you may have a rootworm problem if you grow 
corn in that field in 1971. So check your fields for beetles now to determine what 
you may have next year. 

European corn borers are still with us. As usual, some of the later fields will be 
hit hard. It is now difficult to select fields without making counts . 

If corn is in the whorl stage and if 75 percent or more of the plants are showing re- 
cent whorl feeding, apply carbaryl (Sevin) or diazinon granules. If the corn has tas- 
selled, look for egg masses. If the average is 1 or more egg masses per plant, apply 
an insecticide after a few eggs have hatched. Aerial sprays on tasselled corn are ef- 
fective, but on whorl-stage corn, aerial applications should be granules, not sprays. 
Use 1-1/2 pounds of carbaryl (Sevin), or 1 pound of diazinon, or 1/2 pound of parathioi 
per acre. Allow 10 days between application and silage removal for diazinon and 12 
days for parathion. Parathion should be applied only be experienced applicators. No 
waiting period is required for carbaryl. 

SOYBEANS 

Several insects are chewing on soybean leaves. If they defoliate the plants after 
pods are well formed and almost filled, damage is slight. However, if they are 
actually chewing on the pods, yield loss may be in proportion to pod damage. For 
plants in the stage of development from blossom to early pod fill, loss of 40 percent 
of the leaf surface can be important. If insects are defoliating plants during this 
period of growth, control may be in order. Control is indicated when 25 percent or 
more of the leaf surface has been eaten. 

Grasshoppers can be placed in this category. If possible, spray to control them as 
they migrate into the field. Margin or border spraying is all that may be needed. 

Green cloverworms may be a problem. Spray if beans are between blossom and pod fill,; 
if 25 percent of the leaf surface has been eaten and there are 6 or more worms per 
linear foot of row. To count worms, jar plants over the middle of the row and count 
the worms on the ground. Also watch for dead or dying worms. They become sick with 
a fungus disease during periods of high temperatures and humidity. They will be 
noticed as white, dusty, mummified worms. This indicates that the population is 
decreasing. 

ALFALFA 

Webworms can ruin stands of fall -seed alfalfa. Webbing will be apparent and many 
young plants will be killed as the worms consume the leaves. Sprays of methoxychlor, 
malathion, carbaryl (Sevin) , or several others readily kill these worms if the spray 
penetrates the webbing. As long as the alfalfa is not used for hay the year of 
spraying, residues will not be a problem. 

HOMEOWNER PROBLEMS 

Crickets may soon invade homes . Although there appears to be plenty of cricket food 
in the fields, some of them usually migrate. In so doing, they are attracted to 
lights. A foundation spray of chlordane will help reduce the number that enter the 



home. You may also want to mist spray around doorways and windows. Spray the 
foundation of the house to the point of run-off with 1 percent chlordane spray 
made by mixing chlordane emulsion concentrate with the proper amount of water. 
Avoid spraying near dug wells. 

This will control ants , spiders , Oriental cockroaches , and other pests that migrate 
into the house from outdoors . 

Spiders are controlled by these foundation sprays. As they migrate into the house 
in the fall of the year, they usually cross the foundation. Numbers of spiders 
entering the home will be greatly reduced if the foundation has been sprayed with 
chlordane. We are still trying to determine where the brown recluse spider can be 
found in Illinois. Send spiders to Dr. J.D. Unzicker, Room 95, Natural Resources 
Building, Urbana, Illinois 61801, for identification. 

Clover mites will be seeking winter quarters soon. This may be the side of your 
house as well as behind bark on trees. For permanent control, remove grass for 
an 18 -inch strip around the house. You can plant flowers in this 18 -inch strip 
next spring. You can also spray the foundation and out into the yard as soon as 
you see a few of these mites. Use chlorobenzilate or dicofol (Kelthane) . Follow 
the directions on the lable. 

Flies are more of a nuisance in homes than they have been all summer. Cool nights 
cause them to move in for warmth. The problem will continue for several weeks yet. 
You can help lessen this problem by following these suggestions: 

1. In attached garages apply 0.1 percent or stronger pyrethrin or 0.5 percent 
dichlorvos (DDVP) from a pressurized spray can around and in trash barrels and 
around windows where flies tend to gather. 

2. Keep screens on doors and windows in good repair. 

3. Hang a plastic resin strip containing 20-percent dichlorvos (DDVP or Vapona) , 1 
strip per 1,000 cubic feet of space, or about 1 per room. These strips will kill 
most flies and mosquitoes for 4 to 6 weeks. Do not use these strips in kitchens 
or other areas where food is handled. Do not use them in any room where infants, 
ill persons, or aged persons are confined. A 0.1 percent or stronger pyrethrin 
space spray, applied from a pressurized spray can, can be used in place of the 
dichlorvos resin strips. Repeat treatments will be needed with the space spray. 

4. If you have had a history of problems with cluster or attic flies in winter time, 
watch for swarms of flies under eaves and on the siding on the south and west side 
of your home in September. If large numbers of flies appear, spray the south 

and west sides of the house where the flies are active with dimethoate (De-Fend 
and Cygon) . Mix 1 pint of the 25-percent liquid concentrate in 5 gallons of 
water. The spray will leave a white deposit, and on dark-colored surfaces this 
may be objectionable for awhile. Close all windows when applying the spray. 

Walnut caterpillars are large black worms with gray hairs, that feed on the leaves of 
walnut, hickory, butternut, oak, honey locust, willow, and some fruit trees. Colonies 
of caterpillars feed downward on a branch and may completely defoliate it . They string 
webs down the trunk, shed their skins, and crawl back up the tree to feed some more. 



-4- 

Clumps of shed skins the size of a man's fist are left at the base of the tree. 
The caterpillars are about 2 inches long when full grown. At this time, they 
leave the tree, dig into the soil, and pupate. 

A carbaryl (Sevin) spray, using 2 tablespoons of the 50 -percent wettable powder 
per gallon of water, is effective if needed. 

Slugs in gardens will eat holes in leaves or crowns of plants, leaving a slimy 
residue. They feed at night and are particularly abundant where the foliage is 
dense and close to the ground. A slug can be described as a snail without a shell. 

For control, keep the garden or shrubbery bed free of old garden debris, such as 
leaves, stalks, poles, and boards. Slug baits recently shown to be most attractive 
are stale beer and fermenting grape juice. Stale beer seems to work best. Place 
a shallow pan or large jar top in areas where slugs are numerous. Imbed the con- 
tainer into the soil so that the upper edge is nearly level with the soil surface. 
Fill the container to a depth of 1/2 to 1 inch with beer. Any brand will do. The 
slugs are attracted to the fermenting beer, drop in, and drown (happily). 

Oystershell scale egg hatch is complete in the central and southern sections. The 
young crawlers set up housekeeping on lilac, dogwood, birch, and other shrubs and 
trees. They suck the juices from the plant, and if abundant they can seriously re- 
tard growth and even kill the plant. This is the second generation of this scale 
and the build-up is often heavy. If you have had a history of problems in your 
yard, spray the shrubs thoroughly with malathion, using 2 teaspoons of the 50- to 
57 -percent liquid concentrate per gallon of water. Target dates for spraying are 
right now in the southern sections, August 10 in the central section, and August 20 
in the northern section. 

Diazinon and dimethoate may also be used. Follow the directions on the label. 



WEEDS 
2,4,5-T SUSPENDED 

Since 2,4,5-T registration for use around homes, lakes, ponds, and ditch banks has 
been suspended, what alternatives are available- -especially for control of brush on 
ditch banks? 

Silvex is a phenoxy herbicide that will control many of the same plant species as 
2,4,5-T. In fact, it is more effective for control of some species. Cost is usually 
only slightly higher than for 2,4,5-T. Silvex is still approved for many of the 
same uses as 2,4,5-T was previously used for. 

STORING SPRAYS 

1. Drain all spray material from tank, pump, boom, hoses. 

2. Remove end plugs from boom (if present) so any accumulation there can be flushed 
out. 

3. Fill spray tank with clear water, run pump, and flush water through the boom. 

4. Again fill tank with water to which 1 ounce per gallon of either household 
ammonia or tri- sodium phosphate has been added, and run the pump to discharge 



this through the boom. This will help to neutralize any herbicide residue still 
in the equipment . 

Disassemble nozzles, clean screens, and store screens and nozzle parts dry or 
immersed in a jar of fuel oil. 

Drain pump thoroughly and then coat the inside with a rust -proofing material such 
as soluble oil or regular auto radiator rust inhibitor. This will prevent a stuck 
pump. Be sure pump is dry so it will not be damaged by freezing. 

If tank is susceptible to rust, also rinse or spray-coat the interior with soluble 
oil in water or other rust inhibitor. Do this whenever sprayer will be idle for 
a few days. 

Support boom so it won't be damaged by other machinery. Avoid leaving aluminum 
boom material in contact with soil or manure accumulations. 

Remove hoses, wipe clean of oil, and store them inside, coiled neatly in a 5 -gallon 
pail or straightened out on a shelf. Avoid sharp kinks or hanging over a nail.-- 
From R.E. Doersch and O.I. Berge , University of Wisconsin. 



PLANT DISEASES 



SPRAYING FOR SOUTHERN CORN LEAF BLIGHT 

ihould corn be sprayed to protect it against southern corn leaf blight? That is the 
[uestion that farmers are now asking scientists at the University of Illinois. Per- 
laps the following will help you decide: 

.. The suggested fungicide only gives protection. It does not eradicate infection 
present now on the leaves, ears, and stalks. Thorough coverage of all parts of 
the plants is essential. 

1. No fungicide can be applied to corn that will be used as forage for dairy animals 
or animals being fed for slaughter. This means that only corn being harvested for 
grain can be sprayed with a fungicide. 

i. Spraying will probably be of most value to late -planted corn that is not yet 
approaching the dent stage. 

If corn has not dented, if the upper 5 leaves are free of southern leaf blight 
spots, and if less than 10 to 15 percent of the plants are affected, then 2 or 
more sprays applied at 7- to 10-day intervals--or until the corn is in the dent 
stage --may protect the plants against serious infection. 

i. The suggested fungicide to use on corn intended for grain, to protect it against 
southern leaf blight, is 75-percent wettable zineb (sold as Dithane Z-78, Parzate 
C Zineb Fungicide, Ortho Zineb, Miller Zineb, Niagara Zineb, etc.). The manu- 
facturer's recommendations as regards amount to use per acre (2 to 3 pounds) should 
be carefully followed. Federal agencies only permit use of zineb. 

'. To ensure coverage of the foliage, use 5 gallons or more of water if spraying by 
airplane and 20 gallons or more if using ground equipment. High-clearance sprayers 
are probably preferable if available. 



7. Use nozzles as small as possible to output. Because the fungicide is a wet- 
table powder, the nozzles will tend to clog if their output is less than 
0.5 gallon per minute at 40 p.s.i. Either hollow-cone or flat-fan nozzles 
may be used, but hollow cones are preferred on ground rigs. 

S. On aircraft, point the nozzle outlets forward to promote maximum break up of 
the droplets. 

9. On ground sprayers, use nozzles above the rows and drops between the rows to 
spray into the canopy. 

10. The higher the spraying pressure, the better coverage and control you can ob- 
tain. Aircraft spraying pressures should be 30 p.s.i. or above. Ground 
spraying should be at 80 p.s.i. or above. Little will be gained by spraying 
above 100 p.s.i. with either ground or aircraft. 

11. A pint of surfactant per 100 gallons of spray will reduce surface tension and 
improve coverage and hence disease control. 



READ TEE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Cooley , College 
of Agriculture , Universtty of Illinois at Urbana-Champaign, and the Illinois Natural 
History Survey. 

WEEDS: M.D. McG lamer y , and E.L. Knake , Department of Agronomy. 

PLANT DISEASES: E.E. Burns and M.C. Shurtleff , Department of Plant Pathology. 

AG COMMUNICATIONS: Del Da hi . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




MSECT. WEED & PL ANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GBOUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 21, December 



1970 



SPECIAL ISSUE 



INSECT RECOMMENDATIONS FOR FIELD CROPS 

We receive many inquiries about changes in suggested uses for insecticides before our 
recommendations are published in January. We are sending you these Tentative Sugges- 
tions and Major Changes for 1971 to help answer such questions. Caution statements, 
time limitations between application and harvest, and other precautions are not in- 
cluded . 

These tentative suggestions will appear in final form in University of Illinois College 
of Agriculture Circular 899, which will be sent to the printer by December 10. 

This release was delayed this year waiting for the final decision on certain label clear- 
ances. Minor changes are anticipated. These suggestions are only tentative. 



CHANGES IN THE SUGGESTIONS FROM 1970 

Aldrin and heptachlor . We did not recommend the use of aldrin or heptachlor in 1970 as 
soil insecticides for corn fields urging that all existing supplies be used up. For 
1971, we are advising against the use of aldrin or heptachlor as soil insecticides for 
corn. In arriving at this decision, we considered: 

1. The frequency of damage by those soil-inhabiting pests still controlled by aldrin 
and heptachlor, and the abundance of such pests in corn fields. These insecticides 
no longer give practical control of wireworms, seed-corn beetles, or seed-corn mag- 
gots. 

2. The fact that wireworm populations in fields planted to corn in regular rotations 
are generally low. The profitable use of either aldrin or heptachlor would be most 
likely on first-year corn, following established grass or clover sods. The insecti- 
cide would be broadcast at 1.5 pounds per acre and disked- in prior to planting. 
Wireworms and white grubs might be a problem in such a situation, and aldrin or 
heptachlor would be helpful as control agents. 

5. The previous history of use in Illinois. This indicates that in the approximately 
5 million acres that will be planted to corn, residues of dieldrin-aldrin or hep- 
tachlor epoxide-heptachlor now present may exert a depressing effect on the general 
pest population to the extent that continued applications would not be advisable. 

4. The difficulty encountered in selecting fields that would warrant the use of aldrin 
or heptachlor. This creates problems. A few hundred thousand acres of corn could 
be profitably treated if aldrin or heptachlor were applied broadcast for the con- 
trol of black cutworms. But these fields cannot be selected until damage has oc- 
curred, which is after planting. Therefore, to prevent this damage, it would be 

THE USRARY - 

DEC 14- 1970 

UNIVEKSITY Of ILLINOIS 



necessary in Illinois at apply one of these insecticides to 3 or 4 million acres. 
It will be cheaper to apply control measures when cutworms appear. 

When all treatments were compared with the untreated plots, the stands were so similar 
that seed- attacking insects apparently were not present in damaging numbers. The ac- 
tual insect counts support this. 

Corn Rootworms : Fields infested with corn rootworms were more common in 1970 than in 
1969. Damage by rootworms would have been much more common if 2.7 million acres had 
not been treated with rootworm insecticides. The returns for treatment in demonstra- 
tion fields were about 10 bushels per acre. 

From our demonstration plots, we have drawn the following conclusions: 

1. If a very severe rootworm infestation is anticipated, one pound of carbofuran 
(Furadan) per acre will provide the most -cons is tent results. This has been true 
for three years . 

2. If light to moderately severe infestations are expected, any one of the following 
insecticides will provide practical control: 

Rate, a ctual/A. i 






Planting ~ 
Insecticide time Cultivation 

BUX 1 1 

carbofuran 3/4 

Dasanit 1 1 

Dyfonate 1 

phorate 1 1 

If insecticides are going to be used for cultivation- time treatments, use a seed treate 
at planting time. 

Corn Seed Insects: We want to emphasize the importance of using seed treaters containij 
diazinon to protect against attack by seed-corn beetles and seed-corn maggots. In many 
fields with a long history of aldrin and/or heptachlor use, this may be sufficient- - 
except for corn rootworm infestations. 

Fields Wh ere Roo tworms Are Not a Problem : For those who feel that the seed treatment 
is not sufficient, we suggest instead planting- time treatments as a 7- inch band on the 
soil surface: 

No. lb. actual 
Chemical ingredient/A. 

diazinon 1.5 

Dasanit 1 

Dyfonate 1 

phorate 1 



-3- 

We do not have data on the performance of carbofuran under conditions of severe infes- 
tations , and therefore cannot recommend it for protection against these two seed- 
attacking insects. 

Other Insects: If symphylans are present, Dyfonate has label approval. However, the 
organophosphates and carbamates, as used for rootworm control, may be depressing the 
symphylan populations enough for practical purposes. 

FIELD-DEMONSTRATION RESULTS 

Wireworms were not controlled satisfactorily in sixteen fields where all materials were 
applied as strip treatments. Even aldrin and heptachlor did not control the large, 
nearly mature wireworms . 

Most materials used provided some control of white grubs. The number of seed-com bee- 
tles and maggots in these fields was too small to provide a basis for conclusions. Di- 
rect these materials at the base of the plant in early to mid- June. 

Cutworms : For 1971, we are recommending the use of control measures when the first cut- 
worms begin to appear. This will require careful observation. 

We recommend the use of (1) carbaryl as a bait on an apple-pomance carrier; (2) with 
blackstrap molasses; (3) premixed with molasses (Sevimol) ; or (4) with Tractum, a com- 
mercially available attractant. The last three will be sprayed on the base of the plant 
.and soil at the rate of 2 pounds of carbaryl per acre. The bait will be applied so 
that 1 to 1.5 pounds of carbaryl are used per acre. 

lAvoid the use of molasses baits adjacent to bee hives or near an area that is often fre- 
quented by honey bees . 

POSSIBLE PROBLEMS 

ICertain unwanted effects may occur. Some of these can be prevented with care. The 
following suggestions may help avoid problems: 

1. Surface erosion or run-off. Do not apply any of these insecticides to fields with 
severe slopes that drain directly into ponds or streams. 

2. Seed germination. Some of these insecticides will not affect the germination of 
seeds. Nevertheless, for the time being, we suggest that all of these insecti- 
cides be applied as a 7-inch band on the surface of the soil ahead of the press 
wheel at planting. They should not be directed in a stream into the shoe of the 
planter, as done in the past with aldrin and heptachlor. 

3. Calibration. Calibrate the granular applicator carefully. Check the number of 
acres planted against the pounds of granules used. Do this quite often until the 
exact amount of insecticide is being applied. Excessively high rates are not only 
costly but may be damaging to the crop. 

bux and carbofuran. We are still unsure about the effects of BUX and carbofuran 
on the earthworm populations , but we are not as worried about this as we were 
last vear. 



Although these materials are used only as granules, the potential toxicity to the 
handler and applicator must be considered. Always handle with respect. Do not 
expose yourself unduly. Follow precautions. 

5. Soil insects. We no longer have one insecticide that will control all soil in- 
sects. Therefore, analyze the specific situation and use the practice that will 
best fit the needs involved. 

6. Liquid concentrates. The place of liquid concentrates in liquid starter fertilize 
is still uncertain. Liquid phorate has been removed from the market. Others may 
be used, but any one using this method must practice extreme caution in handling. 
Wear rubber gloves, wash frequently with soap and water (carried on the supply 
truck), and do not contaminate the skin or clothing with these liquid materials. 
If you accidentally spill some on yourself, wash immediately with soap and water 
and then shower and change clothes before proceeding with your work. 

EFFICACY OF INSECTICIDES 

The preceding suggestions for using insecticides have been made after a review of the 
available data. These suggestions have proven to be effective from a practical stand- 
point. However, peculiar situations such as soil texture, the pH of the soil, rainfal 
the slope of a field, wind velocity at planting, the method and accuracy of applicatioi 
as well as other unpredictable factors may decrease the efficiency of the insecticide 
We would appreciate reports of failures in controlling insects and the circumstances 
associated with such failures. 






ALWAYS READ THE LABEL AND FOLLOW ALL PRECAUTIONS 

This special report was prepared by: H.B. Petty, Steve Moore III, Roscoe Randell, Doi 
Kuhlman, and Tim Cooley, College of Agriculture, University of Illinois at Urbana- 
Champaign, and the Illinois Natural History Survey. 



Jz^l 



COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




^SECT WEED & PLANT DISEASE SURVEY BULLETIN 



iTE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



MAY -6 1971 



. 1, April 2, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and commercial vegetables excepted) , along witn 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



GENERAL INFORMATION 



Farmers : Be careful when filling sprayers near wells. Many accidents have oc- 
curred in the past. Keep the hose from the well out of the spray tank- -back- 
siphoning can occur. Be careful not to spill concentrates alongside the well. 
Do not drain sprayers by the well. Follow tnese and other precautions to pre- 
vent problems. Handle insecticides with respect. Always wear gloves. Never 
pour by holding a container above your head. Always pour granules into hoppers 
so that the wind will blow any dust away from you. 

Homeowners: Store pesticides out of the reach of small children. Read and heed 
the instructions and precautions on the label. 



INSECTS 



FORAGE INSECTS 



Alfalfa weevils . Development is slow and corresponds to slow crop growth. This 
could mean that alfalfa weevil larvae will be more damaging than last year. Since 
the larvae will already be feeding when the plants begin to grow, tne tiny new 
shoots may disappear rapidly. 

Adults are present and have been laying eggs. Tiny larvae can be found. Their 
presence will be noticeable in southern Illinois within the next 10 days if air 
temperatures are moderate. In severely infested southern- Illinois fields, we 
expect chemical control will be needed in about 10 days to two weeks, so watch 
fields south of Highway 50. 

We are now making egg- and larval -population surveys. There is already a par- 
ticularly high number of eggs per square foot of alfalfa in some fields in In- 
diana and Missouri. The counts in Illinois are slightly higher than normal. 



Insecticide recommendations are the same as last year, 
unless 25 percent or more of the tips show feeding. 



Do not apply insecticides 



CORN INSECTS 



European corn borer . Survival in the western, southwestern, and southern areas 
is lower than normal. Winter-kill is apparently 10 to 50 percent greater than 
last year. While this does not eliminate the corn borer as a potential problem, 
that potential has been somewhat reduced. 



•2- 



SOIL INSECTS 



There has been some confusion about the cancellation of the aldrin label by the 
Federal Environmental Protection Agency. It is still legal to use and sell al- 
drin . 

A challenge has been issued to the manufacturing company to show evidence that 
the sale and use of aldrin is still justified, and that continued use will be of 
greater benefit to the consuming public than the hazard to the environment. For 
this year, using and selling aldrin is legal. This will continue to be the case 
until a further ruling is made after the conclusion of adequate hearings. That 
will not occur until after the 1971 season, perhaps even after the 1972 season. 

We do not recommend the use of aldrin or heptachlor in Illinois . In most in- 
stances, we feel that this will not be profitable, particularly on fields with 
a history of use. If you do use aldrin or heptachlor, use them only on corn 
planted on sod fields. Do not use aldrin or heptachlor on dairy farms or where 
soybeans are to be grown during the year of treatment. Do not grow soybeans in 
fields where aldrin or heptachlor have been applied for five or more consecutive 
years. If you use aldrin or heptachlor on corn and lose the stand too late for 
replanting to corn, do not plant soybeans in that field. 

Our 1969 and 1970 yield records for corn from nineteen demonstration plots (ten 
with moderate corn rootworm infestations and nine with other insects) show: 

Corn, bu./A. 



Treatment 1969 1970 Average 

Recommended organophosphates 132 109 122 

Recommended carbamates 133 110 123 

Chlorinated hydrocarbons 124 104 116 

Diazinon seed treatment alonef!/ 129 107 120 

Nothing 127 103 117 

a/ Only in sixteen fields. 

HOMEOWNER INSECTS 

Odorous house ants . These are now causing concern. While most ant species only 
live outdoors in colonies, this species lives both indoors and outdoors. Outdoor 
nests are generally located beneath stones and boards; indoor nests, underneath 
floors and in walls . 

To prevent ants, water bugs, spiders, crickets, and other crawling insects from 
entering your home, spray the outside foundation wall with a 1-percent emulsion 
of chlordane and water. Purchase chlordane as a liquid concentrate and mix one- 
half pint of 45-percent chlordane or 10 tablespoons of 72 -percent chlordane in 
5 gallons of water. Spray the foundation wall from the ground to the sill, or 
about a foot, to the point of runoff. In addition, spray 3 to 6 inches of soil 
adjacent to the wall, as well as the expansion joints along porches and steps. 
Do not spray shrubbery or flowers. The oil in the spray may burn the tender 
foliage. 

For controlling ants already inside the home, use 0.5-percent diazinon or 0.5- 
percent Baygon in pressurized spray cans. Spray into all cracks, around base- 
boards, and other areas where the ants are observed. 



Clover mites . They are now leaving their winter hibernation sites. When their 
hiding places beneath siding and in cracks and crevices are warmed by the sun, 
these mites move to window sills and walls on the east and south sides of the 
house. Clover mites are tiny, orange- to -black moving specks about the size of 
the period at the end of this sentence. They cover furniture, curtains, window 
sills, and walls. Although harmless, clover mites leave an unsightly stain when 
mashed. 

Pick them up with a vacuum cleaner or use an 0.1-percent pyrethrin spray from a 
pressurized spray can for a quick knockdown. Before fall, remove the grass, 
clover, and weeds next to the foundation so there is a strip of soil at least 
18 inches wide. This bare soil will serve as a barrier to the mites. 



WELDS 

NEW HERBICIDE CLEARANCES FOR 1971 

Preforan . It has recently received clearance for preemergence use on soybeans. 
It is available as a 3-pounds-per-gallon emulsifiable concentrate and 15-percent 
granules. The broadcast rate is 5 to 6 quarts of the emulsifiable concentrate 
or 25 to 30 pounds of the granules. Preforan should control grasses, pigweed, 
and smartweed. Control will be somewhat erratic on ragweed and jimsonweed. Little 
control is expected of cocklebur, morningglory, or velvetleaf. 

AAtrex-Princep (atrazine-simazine) . This is cleared as a 1-to-l tank mix. It 
will control fall panicum and crabgrass better than AAtrex alone. Rates for the 
mix are one-half the rate of each component when used alone. 

Lasso + Chloro-IPC (alachlor + chlorpropham) . It has received clearance as a 

tank mix. The rate is 2 to 5 quarts each per acre. The purpose of this mix is 

to improve the control of smartweed and a few other broadleaf weeds over the con- 
trol obtained with Lasso alone. 

Treflan . The label now allows the use of a field cultivator for incorporation. 
The rules of thumb to follow when incorporating with a field cultivator are: 
(1) sweeps, not points; (2) penetration, 3 to 4 inches; (3) speed, 4 to 5 m.p.h. ; 
(4) repeat at right angles ; and (5) use a drag harrow to pull treated soil in be- 
hind the back shanks. Other tools such as the double disk or mulch treader may 
be preferable. 

Sutan . Note this supplemental statement: "If it is too late to plant corn again, 
soybeans may be planted providing no atrazine was used with the Sutan. Do not 
plant soybeans sooner than 21 days after application of the Sutan." 

OTHER INFORMATION 

Musk thistle . This is a biennial weed, now on the increase in some areas of 
Illinois. April is the ideal time for control, while the weed is still in the 
rosette stage and before the seed stalk forms. Control is usually best when 
the plant is actively growing and temperatures are above 75° F. 

For spot treatment, add 1 quart of 2,4-D ester (4 pounds per gallon) and 1 cup of 
surfactant or household detergent per 25 gallons of water. Spray until moist. 
For larger infestations, use 1 to 1.5 quarts of 2,4-D ester in 20 or more gallons 
of water per acre. 



Forage crops . We are receiving several questions about the use of herbicides on 
alfalfa. Eptam and Balan are cleared for preplant use when alfalfa is to be es- 
tablished without the aid of a companion crop. These herbicides will give pri- 
mary control only on annual grasses. 2,4-DB, sold under the name of Butyrac or 
Butoxone, can be used to control small annual broadleaf weeds. 

Small grains . Check wheat now to determine the need for chemical weed control. 
Used early, 2,4-D will control many broadleaf weeds such as wild mustard. If 
there is a legume underseeding, apply 0.5 quart per acre of 2,4-D amine. Do not 
use 2,4-D ester with a legume underseeding unless you want to control wild garlic 
or wild onion. Then, expect to kill some of the legume. 

To control wild garlic and wild onion, use 0.5 quart per acre of 2,4-D ester. 
This will not completely control the wild garlic, but will reduce aerial bulblet 
formation and lessen the possibility of harvest- time dockage for "garlicky" wheat. 

Treat small grains with 2,4-D after they have finished tillering in the spring, 
but before they reach the boot stage- -when the crop is 4 to 12 inches high. 

SAFETY REMINDERS 

As a pesticide dealer, you are in a unique position to help improve the safety 
record of pesticides in Illinois. You represent the last contact with the pes- 
ticide user. Read the label and its precautions. Pesticides bearing the skull 
and cross bones are very highly toxic and should be handled with special care. 

Pesticide concentrates (materials with a high percentage of active ingredients) 
are more hazardous than diluted materials. Check for leakers among pesticide 
containers . Do not toss or drop containers . 

Store and display pesticides in areas away from articles for human or animal 
consumption or use. 

Urge your customers to read the label, to observe precautions and use directions, 
and to store pesticides properly away from food and plants in a cabinet or closet 
that can be locked. Also, remind your customers of the need for proper use and 
disposal. Tell them never to use an empty pesticide container for other purposes. 

Many of the pesticide ingestions in Illinois each year involve small children who 
find pesticides improperly stored, often in unlabeled containers. 



PLANT DISEASES 

SOUTHERN CORN LEAF BLIGHT 

Ed Burns has been collecting corn samples in three widely scattered areas in 
Illinois--Elwood (near Joliet) , Champaign- Urbana, and Dixon Springs. This is to 
check on the overwintering of the southern corn leaf blight fungus. Ed has col- 
lected debris from five different tillage methods and from both resistant (N) 
and susceptible (T) hybrids at monthly intervals. So far, the fungus has been 
killed in the soil, and is in a weak state in the corn debris above ground. Al- 
ternate freezing and thawing plus wetting and drying have practically killed the 
fungus in all three locations. 



Corn samples collected from cribs in ten widely scattered counties in Illinois 
show that the SCLB fungus is alive and highly virulent in dry corn. This should 
be our main source of local infection during 1971. So we suggest that farmers 
shell-out blighted com in their crib before they plant this year's crop. 

Planter-box treatment . The emergence and stand of infected T and B seed corn 
can be increased by about 10 percent with a planter-box treatment of captan, 
thiram, or maneb seed protectant. Use 1 to 2 ounces of actual fungicide- -2 to 
4 ounces of formulated material- -per bushel of seed. We suggest mixing the fun- 
gicide with the seed in the planter box. Some of the dust will fall around the 
seed when it drops and will help prevent preemergence damping-off . 

DuPont has a thiram seed protectant (arasan 50-Red) , formulated for use in the 
planter box. The Hopkins Agricultural Chemical Company of Madison, Wisconsin, 
has formulated a thiram-maneb treatment. Both the Arasan and the thiram-maneb 
treatments contain graphite to help prevent plugging or planter "drag." 

TREATING OAT SEED 

Since the "hard" mercuries were banned a year ago, many farmers have asked what 
they should use for treating oats and wheat in 1971. There are several possi- 
bilities . 

1. You can still apply any leftover ceresan, panogen, ortho L M, or chipcote. 
The ban means that these products cannot be shipped across state lines any- 
more and that their manufacture has been largely discontinued. 

2. The next best bet would probably be products that contain phenyl mercuric 
acetate (PMA) . This is a liquid (0.078 ounce per bushel), formulated for 
use in Mist-O-Matic and similar treaters. It is "soft" mercury that does 
not accumulate in body tissue and has label clearance. Mercuries are the 
only fungicides that are volatile and will kill-out fungus spores under the 
seed coat. 

3. Other possible seed treatments include captan- -2 ounces per 100 pounds, ap- 
plied dry, or 2.8 ounces per 100 pounds as a slurry- -and Chloranil (Spergon) , 
applied dry, using 6 ounces per 100 pounds. 

4. There are additional products that have label clearance, but they are either 
hard to get or difficult to handle. These include formaldehyde- -1 pint per 
40 gallons of water or 1 pound of dust per 15 gallons of water; hexachloro- 
benzene (HCB)--0.2 ounce of actual chemical per bushel, applied dry or as a 
slurry mix; maneb- -1 ounce of actual chemical per bushel; raformaldehyde-- 

3 ounces per bushel; and zineb--0.5 ounce per bushel. 

Note: We have not had the opportunity to test these products on oats. 



READ THE INSECTICIDE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman, and Tim Cooley , 
College of Agriculture, University of Illinois at Urbana-Champaign , and the Il- 
linois Natural History Survey. 



-6- 

WEEDS : Ellery Knake and Marshal McGlamery , Department of Agronomy. 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 

AG COMMUNICATIONS : Ray Woodis 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




MSECT. WEED & PLANT DISEASE SURVEY BULLETIN 



! IVTE/COUNTY/LOCAL GROUPS U.S. DEPARTMENT OF AGRICULTURE COOPERATING 

OR IMMEDIATE RELEASE No. 2, April 9, 1971 

his series of weekly bulletins provides a general look at the insect, weed, and plant 
isease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
reviated control measures. Each individual should check his own fields to determine 
ocal conditions. 



INSECTS 



ORAGE INSECTS 



lfalfa weevil. Their development and that of the crops has been slowed down by the cold 
eather this past week. Insects usually develop at a slightly faster rate than plants 
uring these cool periods. 

he likelihood of serious damage by alfalfa weevil larvae is greater if temperatures re- 
ain on the cool side. 

dult weevils are continuing to lay eggs and young larvae are hatching. These tiny, 
ream-colored larvae (not green yet) can be found tunnelling into leaf buds and working 
nto folded leaves. Presently, this feeding is minor and hardly noticeable. 

opulations of this insect will vary greatly from area to area and even from field to 
ield. Treatment with an insecticide is justified when 25 percent of the tips show 
eeding and the larvae are still present. Do not apply insecticides unless they are 
eeded. We would expect insecticide applications to be warranted within 10 days to two 
eeks in the extreme southern section of the state, two to three weeks in the south - 
entral section, and three to five weeks in the central section. 



tie insecticide recommendations are: 

. Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azinphosmethyl 
(Guthion) for good results. Use azinphosmethyl only once per cutting. Do not harvest 
for 15 days after treatment with methyl parathion, or 16 days for azinphosmethyl. Wear 
protective clothing. 

. Persons not equipped with protective clothing . Use: (1) Imidan at 1 pound per acre; 
(2) a mixture of 3/4 pound of malathion and 3/4 pound of methoxychlor per acre; (3) a 
mixture containing at least 1/2 pound of diazinon and 1 pound of methoxychlor per acre; 
or (4) 1-1/4 pounds of malathion per acre on days when air temperatures will be above 
60° F. for several hours after application. Do not harvest for 7 days after treatment 
with Imidan, methoxychlor, diazinon, or mixtures of them. There is no waiting period 
for malathion. Do not apply Imidan more than once per cutting. 



Using ground equipment . 
4 gallons by air. 



Apply a minimum of 20 gallons of finished spray per acre, or 



-2- 

Clover leaf weevils . The larvae resemble those of the alfalfa weevil, but feed at night 
and hide in ground debris during the day. Check red clover fields that have had a heavy- 
straw or mat covering. The green worms with a white stripe down the back will be found 
under the debris, and the clover will show irregular holes in the leaves from their feed 
ing. Clover can usually recover from the damage. However, severe damage could occur in 
some fields should the cool weather continue. 

If plant growth is slow and leaf feeding becomes severe, a spray of 1 pound of malathion 
per acre (or mixtures of malathion or diazinon and methoxychlor) will control this insed 
For best results, apply malathion only when air temperatures are 60° F. or above. 

CORN SOIL INSECTS 

There has been some confusion about the cancellation of the aldrin label by the Federal 
Environmental Protection Agency. Although we do not recommend the use of aldrin or heptc 
chlor in Illinois, it is still legal to use and sell aldrin for corn-soil application . 

In most instances, we feel that this will not be profitable, particularly on fields with 
a history of use. In many of these cases, diazinon seed treatment may be sufficient. Ii 
you do use aldrin or heptachlor, use them only on corn planted on sod fields. Do not use 
aldrin or heptachlor on dairy farms or where soybeans are to be grown during the year of 
treatment. Do not grow soybeans in fields where aldrin or heptachlor have been applied 
for five or more consecutive years. If you use aldrin or heptachlor on corn and lose the 
stand too late for replanting to corn, do not plant soybeans in that field. Dasanit, 
diazinon, Dyfonate, and phorate (Thimet) have been steadily replacing aldrin and hepta- 
chlor in general-use situations for corn-soil application. Along with carbofuran (Fura- 
dan) and BUX, they have almost completely replaced aldrin and heptachlor for rootworm 
control . 

HOMEOWNER INSECTS 

Brown recluse spider . This species continues to attract much attention in Illinois. Dr. 
J.D. Unzicker, Taxonomist at the Illinois Natural History Survey, has identified brown 
recluse spiders from 47 of the 102 counties in Illinois (see map) . 



The body of this spider is about half an inch long. The leg span is an inch to an inch 
and a half. The color may vary from light fawn to almost dark brown. There is a dis- 
tinct, fiddle -shaped, dark marking behind the head (see picture). 



• 



Although reports of persons bitten by this spider are not numerous, its bites are poison- 
ous and the brown recluse is considered to be of public health importance. Unfortunately 
the origin of bites is usually unknown. Most are attributed to the brown recluse spider 
because of the resulting wound. This spider bites only when disturbed. The brown reclus 
has a habit of living in dark, sheltered areas (such as attics), in storage areas, base- 
ments, crawl spaces, and barns. Unlike other web-spinning species, it spins very small 
or irregular webs. 

According to Dr. Unzicker, the brown recluse is a southern species that cannot survive 
the winter outdoors in central and northern Illinois. Consequently, it prefers to live 
in or near houses or buildings and inside stored items. Dr. Unzicker suggests consulting 
a physician about any spider bite. Little or nothing is known about the bites of many 
common household spiders. It is possible that other species may be responsible for bites 
similar to those of the brown recluse. 




he are cataloging the distribu- 
tion of this spider and others 
in Illinois. For identification, 
send all spiders to Dr. John 
Unzicker, Room 93, Natural Re- 
sources Building, Illinois Natu- 
ral History Survey, Urbana, Illi- 
nois 61801. Include your name, 
address, and where the spider was 
found. Dr. Unzicker will iden- 
tify the one you found and send 
you this information. When 
spider bites occur, capture the spider if possible 
and send it to Dr. Unzicker for identification. 



If no brown recluse spiders have been identified 
in your county, be sure to send us suspect spiders 
so we may confirm distribution. (See map.) 

hinged termites and ants . They are making their 
spring appearance and are causing concern to 
homeowners. They can be distinguished from each 
other rather easily. A flying termite is always 
black. A flying ant may be black, yellow, tan, 
or almost red. The back wings of an ant are 
shorter than the front wings . The two pairs of 
wings on a termite are of equal size. An ant has 
a constricted, or narrow, waist just behind the 
wing-bearing section of the body. The termite 
has no such constriction. The antennae of ter- 
mites are straight, those of ants are elbowed. 
The diagram shows the major differences. 




Date indicates the year the spider was firt found in the county. 



April 1, 1971. Places where the 
brown recluse spider has been 
found in Illinois . 



TERMITE or ANT? the differences are: 



TERMITE 




WINGS(IFPRESENT) 
MANY SMALLVEINS 
BOTH WINGS 

SAME SIZE 



ANTENNA 
NOT ELBOWED 



ANTENNA ELBOWED 

ANT 



"CHEMISE" 
V WAIST 

"HOUR 
GLASS 
WAIST 




WINGS 

"(IF PRESENT) 
FEW VEINS 
^"HIND WINGS SMALLER THAN 
FRONT WINGS 



If swarms of flying termites appear, check for mud tubes on the inside and outside of 
the foundation walls. Many termite problems are extremely complicated and require an 
experienced exterminator. 



WEEDS 

NEW HERBICIDE CLEARANCE 

Lorox- Lasso for corn. A tank mix of this combination is now cleared for use on corn 
as well as soybeans. The rates are about the same as those given with the recent 
clearance for soybeans. They vary with soil type and organic -matter content. The 
ratio is about 1 pound of 50W Lorox (commercial product) to 1 quart of Lasso. The 
rates would vary from 1 + 1 to 2-1/2 + 2-1/2 per acre. 

TIMING PREPLAN! HERBICIDE APPLICATIONS 

Treflan . It can be applied up to ten weeks prior to planting. Incorporation can be 
delayed up to 8 hours --but the sooner the better, especially if the ground is moist and 
the sun is hot. 

Planavin . Application can be made up to six weeks prior to planting soybeans. Incor- 
poration can be delayed up to 48 hours . 

AAtrex. This can be applied up to two weeks prior to planting. There is no hurry about 
incorporation to avoid surface loss. 

Sutan. It can be applied up to two weeks prior to planting. Immediate incorporation is 
necessary. 

Vernam liquid . This can be applied up to 10 days prior to planting soybeans. Immediate 
incorporation is necessary. 

Lasso. This can be applied preplant on soybeans or corn within 7 days of planting. In- 
corporation is recommended only for control of nutsedge. A higher rate is desirable if : 
Lasso is incorporated. In general, there is no hurry to incorporate Lasso as there is • 
little- -if any- -surface loss. 



PLANT DISEASES 



WINTER-WHEAT AND OAT-SEEDLING PROBLEMS 

Most of the specimens received in our plant disease clinic recently have been winter whe: 
and oats. The same symptoms appear on all the plants. The older leaves are dying or del 
Occasionally, there is leaf discoloration- -purple or yellow. These symptoms usually ap- 
pear uniformly throughout the field. When a primary pathogenic organism is not isolated 
the problem can be attributed to winter injury. 

In Illinois, heaving probably causes most of the winter killing. Plants are lifted from 
the soil by alternate freezing and thawing, leaving root tissue unprotected and often 
broken. The plants should survive if the roots of the young plants appear healthy- -whit* 
and sturdy- -and the new leaves are a normal green color. 



-5- 
These are other disease problems that may affect plant seedlings : 

1. Scab. The plants will be stunted and yellow, some dying. The roots will be rotted 
and reddish -brown. 

2. Spot blotch . This is a dark -brown rot, at or beneath the soil line. The leaves 
will be erect and dark green, with dark brown spots. 

3. Speckled leaf blotch . The leaves will have circular to oval, light-green spots with 
black specks (Septoria fruiting bodies). Later in the spring, the tillers die and 
are covered with black fruiting bodies. 



SAFETY REMINDERS 



Preventing chemicals from getting into wells is much cheaper and easier than taking care 
of the problem afterward. The most -frequent causes are flushing or overflowing sprayers 
near wells or hose -siphoning while sprayers are being filled. If a loss of pressure occurs, 
it would be possible for chemicals to get from a spray tank into a municipal water supply 
by siphoning. 

Here are some tips on prevention: 

1. Do not leave the sprayer unattended while filling the tanks. 

2. Do not flush tanks where the chemical (s) will drain into wells. 

3. Do not place the hose in the tank. A bracket to hold the hose and the tank will pre- 
vent siphoning. 

If the material gets into a well, this problem must be dealt with immediately. First, de- 
termine the use of the well water. Is it used for human or animal consumption or only to 
irrigate a garden? Second, determine the chemical (s) involved and their toxicity. Third, 
start to pump the well as soon as possible, disposing of the water in a suitable manner. 
Some materials, such as Treflan, Lasso, or 2,4-D ester, will be visible in the water--even 
in dilute amounts. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , College of 
Agriculture, University of Illinois at Urbana-Champaign , and the Illinois Natural History 
Survey . 

WEEDS: Ellery Knake and Marshal McGlamery , Department of Agronomy. 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 

AG COMMUNICATIONS: Ray Woodis . 

The information for this report was gathered by these people, staff members, county Exten- 
sion advisers, and others, in cooperation with the USDA Agricultural Research Service, 
Plant Pest Control Branch. 



NOTE TO COUNTY EXTENSION ADVISERS 

You have received a copy of Home and Garden Bulletin No. 67, Insects and Related Pests 
of House Plants. If you need more copies, let us know. We will fill orders as long as 
our shelf supply lasts. This bulletin can also be purchased for 10 cents per copy from 
the Superintendent of Documents, Government Printing Office, Washington, D.C. 20250. 



%2L / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



iTATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 5, April 16, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual fihpuld check_his own 
fields to determine local conditions. 

MAY - 6 1971 



INSECTS 



FORAGE INSECTS 



UNIVERSITY OF ILLINOIS 

r-r MOD4(\|A.rM0.MPAIGri 



Alfalfa weevils . The cool weather is slowing larval development, egg hatch, and 
alfalfa growth. However, adult weevils are present and continue to deposit eggs. 
An extended period of warm weather in southern and south- central Illinois could 
bring about a sudden hatch and a rapid build-up of larvae, with accompanying dam- 
age. Treatments may be justified in an occasional field this coming week south 
of Highway 13. Last week, larval populations south of this line ranged from 1 to 
6 per sweep (about 20 per sweep is considered an economic infestation) , with 20- 
to 80-percent of the plants showing slight tip feeding. One field had 55 larvae 
per square foot, but the number was considerably less in most fields. Feeding 
damage and larval populations are hardly noticeable north of Route 15. Depending 
on weather conditions, we would expect treatments in the south-central area to be 
warranted within ten days to two weeks and two to four weeks in the central section. 

As you examine alfalfa, the yellowish, newly hatched larvae (about 1/20-inch long), 
with shiny black heads, can be found feeding within the folded leaves and buds of 
the plant terminals. Occasionally, an almost -mature larva may also be found. These 
are green with a white stripe down their back. 

Watch all fields closely from now on. Our egg surveys show that some fields nave 
a fairly high concentration per square foot. Populations of this insect vary 
greatly in fields only a short distance apart, so every field must be evaluated 
individually. Treatment with an insecticide is justified when 25 percent of the 
tips show feeding and larvae are present. Do not apply insecticides unless they 
are needed. 



The insecticide recommendations are: 

1. Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azin- 
phosmethyl (Girth ion) for good results. Use azinphosmethyl only once per cutting. 
Do not harvest for 15 days after treatment with methyl parathion, or 16 days for 
azinphosmethyl. Wear protective clothing. 

2. Persons not equipped with protective clothing . Use: (1) Imidan at 1 pound per 
acre; (2) a mixture of 3/4 pound of malathion and 5/4 pound of methoxychlor per 
acre; (3) a mixture containing at least 1/2 pound of diazinon and 1 pound of 



-2- 

methoxychlor per acre; or (4) 1-1/4 pounds of malathion per acre on days when 
air temperatures will be above 60° F. for several hours after application. Do 
not harvest for 7 days after treatment with Imidan, methoxychlor, diazinon, or 
mixtures of them. There is no waiting period for malathion. Do not apply Imidan 
more than once per cutting. 

5. Using ground equipment . Apply a minimum of 20 gallons of finished spray per acre, 
or 4 gallons by air. 

Clover leaf weevils. These can be found in an occasional red clover field, but pop- 
ulations thus far are not very high. The larvae are green with a white stripe down 
the back. They feed at night and hide under the ground debris during the day. Dam- 
aged clover will have irregular holes in the leaves from their feeding, but will 
usually recover. Severe damage could occur in some fields if the cool weather con- 
tinues. 

Check red clover fields that have a heavy straw or mat covering. If plant growth 
is slow and leaf feeding becomes severe, a spray of 1 pound of malathion per acre 
(or mixtures of malathion or diazinon with methoxychlor) will control this insect. 
For best results, apply malathion when air temperatures are 60° F. or above. 

SOIL INSECTS 

We continue to receive questions about the cancellation of the aldrin label by the 
Federal Environmental Protection Agency. Although we do not recommend the use of 
aldrin or heptachlor in Illinois, it is still legal to use and sell aldrin for corn- 
soil application . 

A challenge has been issued to the manufacturing company to show evidence that the 
sale and use of aldrin is still justified, and that continued use will be of greater 
benefit to the consuming public than the hazard to the environment. For this year, 
using and selling aldrin is legal. This will continue to be the case until a fur- 
ther ruling is made after the conclusion of adequate hearings. That will not occur 
until after the 1971 season, perhaps even after the 1972 season. 

In most instances, we feel that aldrin and heptachlor will not be profitable, par- 
ticularly on fields with a history of use. In many of these cases, diazinon seed 
treatment may be sufficient. If you do use aldrin or heptachlor, use them only on 
corn planted on sod fields. Do not use aldrin or heptachlor on dairy farms or where 
soybeans are to be grown during the year of treatment. Do not grow soybeans in fields 
where aldrin or heptachlor have been applied for five or more consecutive years. If 
you use aldrin or heptachlor on corn and lose the stand too late for replanting to 
corn, do not plant soybeans in that field. Dasanit, diazinon, Dyfonate, and phorate 
(Thimet) have been steadily replacing aldrin and heptachlor in general-use situations 
for corn-soil application. Along with carbofuran (Furadan) and BUX, they nave almost 
completely replaced aldrin and heptachlor for rootworm control. 

CORN INSECTS 

European corn borers . Tie survival of overwintering borers is lav in the southern 
and western areas of Illinois where there was little or no snow cover during the 
winter. Survival is higher in northern Illinois wherever the snow cover was more 
extensive. Although the overall survival is apparently lower than last year, this 
does not eliminate the corn borer as a potential problem. Reports on com borer 
survival from Extension advisers were received from El don Starkweather in Greene 
County and Bob S clime rbauch in Wayne County. 



HOMEOWNER INSECTS 

Garden soil insects (including wireworms, seed and root maggots, and white grubs) . 
These can be controlled by mixing 1 ounce actual diazinon or 4 ounces of diazinon 
25-percent liquid concentrate per 1,000 square feet of garden area. Apply as a 
broadcast treatment to the soil surface prior to planting, and thoroughly mix the 
chemical into the top 4 to 8 inches of soil. Do not use aldrin, heptachlor, or 
other insecticides that are labeled for corn- soil insect control. 

Ornamental and lawn pests . Now that spring yard work has begun, questions are 
coming in about insect pests on ornamental plants. Euonymous scales , common on 
shrubs like winter creeper and euonymous evergreen ground cover, may be confused 
with insect eggs. Although nothing can be done to control these pests now, spraying 
with malathion after the eggs of these scales hatch will be helpful- -in late May for 
pine needle and sweet gum scale ; in early June for scurfy , oysters he 11 , and euonymous 
scale ; and in early July for cottony maple , Juniper , and dogwood scales . 

Sawdust from borers in the trunks of trees and shrubs can be found on the bark or 
accumulating at the base of the trunk. The tunnels of the borers can be probed with 
a wire to kill the borers, or dimethoate sprays (25-percent De-Fend W.P.) or Cygon 2E 
can be used in late May or early June. Wrapping the trunks of newly set trees with 
heavy paper for two years, or until the trees are growing vigorously, will help pre- 
vent attacks by borers. 

Now is a good time to pick off last year's bagworms from the evergreen or other trees 
and destroy them. About half of these bags are full of eggs that will hatch within 
four to eight weeks. The more eggs that are destroyed now, the easier it 'will be to 
control the bagworms later. 

Last fall's damage to lawns by the sod webworm is ancient history. It is too early 
to take action against the damaging second-generation, which hits in early August. 
However, a vigorous, well-fertilized lawn is the best plan of attack to ward off 
damage by the first generation. 

Fruit and shade trees . For those with a few fruit trees, Circular 1001 "Home Or- 
chard Pest Control" shows the spray schedules for apple, peach, cherry, pear, ap- 
ricot, and other fruit trees. This circular is available at the office of the county 
Extension adviser, or from the Office of Agricultural Publications, 123 Mumford 
Hall, Urbana 61801. 

Maple bladder galls are small, wartlike growths on the upper surface of leaves of 
young silver or soft maple trees. These galls are caused by mites that overwinter 
in the buds of the trees. When leaves begin to emerge in the spring, these mites 
infest the new leaves. Control is rarely necessary, since these galls will seldom 
damage the tree or its branches. If chemical control is attempted, timing the spray 
with the emergence of the new leaves will increase the chances for success. Use 
malathion, 57-percent liquid concentrate, at the rate of 1 cup per 25 gallons of 
water. 



WEEDS 

NUTSEDGE--A TOUGH NUT TO CRACK 



Yellow nutsedge (Cyperus esculentus) , often called nutgrass, is becoming a serious 
weed problem in many areas of Illinois. It is a sedge (triangular stem and three- 
ranked leaves) rather than a true grass (round stem and two-ranked leaves) . 



Nutsedge overwinters primarily as tubers (nutlets) that sprout in the spring and 
form rhizomes. A coronal node forms on the rhizome about 1 to 1-1/2 inches below 
the soil surface. From this crown area roots, shoots, and new rhizomes form. The 
rhizomes produce plants at first, but later in the season they tum down and develop 
new tubers for overwintering. 

The crown area that develops below the surface of the soil is a critical area for 
yellow nutsedge control. The most -effective control program involves a combination 
of preplant tillage, an incorporated herbicide, and postplant tillage. Nutsedge is 
usually found in low- lying, wet areas. It usually emerges about the corn-planting 
time or when the sprouts come up. 

Controlling nutsedge in soybeans is generally easier than in corn, because soybeans 
are planted later. This gives the farmer time to locate isolated areas of nutsedge 
infestation, use preplant tillage, and broadcast a herbicide just on those areas. 
The two herbicides that have proven useful for nutsedge control in soybeans are 
alachlor (Lasso) and vernolate (Vernam) . Both should be used at the highest rec- 
ommended rate, and should be incorporated. This can be combined with preplant 
tillage. 

The herbicides used for nutsedge control in corn are alachlor (Lasso) , butylate 
(Sutan) , and atrazine (AAtrex) . EPTC (Eptam) has provided adequate control, but 
the corn tolerance has not been sufficient. The best treatments in research trials 
on corn have been either butylate (4 pounds per acre) or alachlor (5 to 4 pounds 
per acre) --applied preplant, incorporated, and followed by an early postemergence 
treatment of atrazine (2 pounds per acre) plus nonphyto toxic oil (1 gallon per acre). 

CHECK WEEDY SPOTS 

It pays to check fields for weedy spots during the spring. Giant ragweed is now 
germinating, and smartweed will soon start. These are two of the first field 
problems with weeds. Giant foxtail and pigweed will start germinating in about 
one to two weeks, depending on the temperature. I 

If you find areas of high infestation, it might be worthwhile to consider broad- 
casting a herbicide on these potential trouble sports. Such areas are often found 
along drainageways , turn- rows, headlands, and fence lines --places where it is most 
difficult to cultivate. Use a band application of herbicide on these areas. Cul- 
tivate the rest of the field. 

TANK-MIXING HINTS 

Many herbicides are being applied with liquid fertilizers. Problems of compatability 
sometimes arise when emulsifiable concentrates are mixed with liquid fertilizers be- 
cause the emulsifier is not salt-stable. Some manufacturers have special pesticide 
formulations for liquid-fertilizer application. Others specify that the emulsion 
stability must be checked and if needed, that a compatability agent such as Compex 
or Sponto/68 be added. 

Check compatability in quart jars before mixing an entire tankful . First, deter- 
mine the volume of spray per acre. With liquid fertilizers, this will depend on 
the analysis used and the rate desired. Next, determine the volume or weight of 
the pesticide to be applied per acre. Then, convert the number of quarts or pounds 
of additives and gallons of spray carrier to the amount per pint of spray. 



NOTE TO RADIO AND TV STATIONS 

Our automatic telephone answering service will provide the following insect situation 
recordings, starting on Monday, April 26: 

Homeowner Insect Problems- -each week. 

Calling time- -9 a.m. Monday to 8 a.m. Tuesday. 

Dial (217) 333-2614. 

Southern Illinois Field Insect Situation --each week. 
Calling time- -1:00 p.m. Thursday to 9:00 a.m. Friday. 
Dial (217) 333-2614. 

Northern Illinois Field Insect Situation- -each week. 
Calling time- -10: 00 a.m. Friday to 8:00 a.m. Monday. 
Dial (217) 333-2614. 

Each recording will be two minutes long. In case of questions or difficulty, call 
Ron Scherer (217) 333-4783. 

HOW TO SEND IN SPECIMENS FOR IDENTIFICATION 

To facilitate rapid and positive identification of insect specimens that we receive, 
please note the following suggestions: 

1. Send soft-bodied specimens in a crush-proof container, such as a plastic pill vial 
containing rubbing alcohol. Do not use formaldehyde. Wrap the vial in cotton or 
paper for sending through the mails. 

2. Place adult specimens in a plastic vial and wrap with cotton or paper. Alcohol 
need not be used. 

3. Give the date, county and town, and information about where the insect was found. 
For examples: beneath the kitchen sink, in a box of cereal, on a maple tree, on 
soybeans . 

4. Do not attach specimens to the letter with scotch tape. Stamp -cancelling machines 
in the post office usually reduce specimens to a small pile of pulverized pieces, 
making identification difficult if not impossible. 

THANKS. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell, Don Kuhlman , and Tim Coo ley , College 
of Agriculture, University of Illinois at Urban a- Champaign , and the Illinois Natural 
History Survey. 

WEEDS: Ellery Knake and Marshal McGlamery , Department of Agronomy. 

AG COMMUNICATIONS: Ray Woodis. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



fATE/COUNTY/LOCAL GROUPS U.S. DEPARTMENT OF AGRICULTURE COOPERATING 






FOR IMMEDIATE RELEASE 









No. 4, April 23, 1971 



This series of weekly bulletins provides a general look at the insect , weed, and 
plant disease situation (fruit and aommeraial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



GENERAL INFORMATION 



Insect development has been at a practical standstill until recently. When a 
cool spring suddenly "breaks" into summer, insect development, retarded early, 
accelerates, and everything seems to happen at once. If warm weather continues 
generally over the state, expect appearance of insects in northern Illinois about 
as soon as in southern Illinois. Also expect many species to appear all at once-- 
some earlier than usual and some later. 



INSECTS 



FORAGE INSECTS 

Alfalfa weevils . Feeding became evident in most alfalfa fields in extreme south- 
ern Illinois this past week, and severe damage has occurred to some fields. Pop- 
ulations of the green worms are high, and there are still many eggs to hatch. 
Spray applications should be made immediately in severely infested fields . Con- 
sider cutting instead of spraying in severe cases. 

In the area north of Highway 13 and south of Highway 50, larvae are evident and 
damage is increasing rapidly. Adults are still numerous and continue to deposit 
eggs in alfalfa stems. The situation will be critical for the next ten days. 

In the area north of Highway 50 to Highway 36, the development is a bit slower. 
Larvae are numerous but adults are present in large numbers. The next ten days 
to two weeks are critical in the south part of this area, but it will be two weeks 
or more before decisions regarding treatment will be required in the north part 
of this area. 



North of Highway 36 it will still be two to four weeks before infestations are se- 
rious . 

The above estimates are based on normal temperature and rainfall expectations . 
Should spring "bust out all over" at the same time and to the same degree, the 
time lapse in development will be greatly narrowed. 

The insecticide recommendations are: 

1. Commercial applicators . Apply 1/2 pound per acre of methyl parathion or az- 
inphosmethyl (Guthion) for good results . Use azinphosmethyl only once per 
cutting. Do not harvest for 15 days after treatment with methyl parathion, 
or 16 days for azinphosmethyl. Wear protective clothing. 



2. Persons not equipped with protective clothing . Use: (1) Imidan at 1 pound 
per acre; (2) a mixture of 3/4 pound of malathion and 3/4 pound of methoxy- 
chlor per acre; (3) a mixture containing at least 1/2 pound of diazinon and 
1 pound of methoxychlor per acre; or (4) 1-1/4 pounds of malathion per acre 
on days when air temperatures will be above 60° F. for several hours after 
application. Do not harvest for 7 days after treatment with Imidan, methoxy- 
chlor, diazinon, or mixtures of them. There is no waiting period for mala- 
thion. Do not apply Imidan more than once per cutting. 

5. Using ground equipment . Apply a minimum of 20 gallons of finished spray per 
acre, or 4 gallons by air. 

Clover leaf weevil . Larvae of this pest resemble alfalfa weevil larvae. Both 
are green with a light- colored stripe down the back. One thing is noticeably 
different- -the head capsule of the clover leaf weevil is brown not black as that 
of the alfalfa weevil. Also clover leaf weevils are usually larger. In hot, 
muggy weather they die in large numbers from a fungus which penetrates their body. 
Alfalfa weevils are not affected by this fungus. 

Fields of red clover examined in the southern one- third to one-half of the state 
this week indicate that clover leaf weevil larvae are present in considerable num- 
bers , but the clover is growing away from their feeding damage and no spraying is 
recommended. 

SMALL GRAIN INSECTS 

Armyworm moths can now be seen at lights at night. These light brown, heavy- 
bodied moths have a white dot on each forewing. They will deposit eggs on grasses, 
including small grains, in the most vigorous areas in these fields. Abundance of 
moths is not known, and it will be three to five weeks before the potential can be 
determined. 

CORN INSECTS 

Black cutworms . Moths of this pest can also be seen at lights at night. These 
purplish-brown, heavy-bodied moths are often present at this time of year. As 
with armyworms, it is difficult to determine potential infestations by moth flight. 

Usually these moths deposit their eggs in low spots in fields, particularly if 
these spots are wet. Time alone will tell where these moths may deposit eggs this 
year if present weather conditions continue . 

HOMEOWNER INSECTS 

Many species of aphids are beginning to appear on trees and shrubs, especially haw- 
thorne and crab apple. The green, soft-bodied plant lice suck the sap from the new 
leaves, causing the leaves to curl, but rarely do severe damage to the tree. If 
aphids are very numerous, a spray of either diazinon or malathion will control them. 
Follow mixing directions on the label. Do not use malathion on canaert red cedar 
or diazinon on ferns or hibiscus plants. 

Fungus gnats are beginning to appear inside homes now. These small flies develop 
in wet, decaying organic matter. If they are a nuisance inside the home, a spray 
of 0.1-percent pyrethrins applied from a pressurized can will give temporary relief. 



Now is the time to control European pine shoot moth on white, red, Scotch, or muhgo 
pine. The brown larvae with black heads have begun to tunnel into shoots. Spraying 
with dimethoate (Cygon, De-Fend) will control the first generation in April; the 
second generation can be controlled in mid- June. Removing the infested shoot tips 
before June will aid in the control of this insect. 

Eastern tent caterpillars are feeding on trees, especially wild cherry, in southern 
Illinois. Young caterpillars have hatched, are feeding on the new leaves, and are 
spinning webs on the trunk and in limb crotches . Spraying with carbaryl (Sevin) or 
malathion will control this insect. The webbing does provide some protection to 
the caterpillar and can prevent spray penetration to give effective control. 



WEEDS 
HERBICIDE INCORPORATION 

Most annual weed seeds germinate in the top 2 inches of soil. And most moderately 
soluble herbicides move into the weed-seed zone with normal rainfall. The primary 
purpose of herbicide incorporation is to prevent surface loss of volatile herbi- 
cides and to move less soluble herbicides into the soil. 

A disk is the most common tool for herbicide incorporation. Run a tandem disk about 
4 inches deep for best results. Greater depths may cause excessive dilution of the 
herbicide. Field cultivators, in general, do not give satisfactory herbicide incor- 
poration. The Treflan label allows the use of a mulch treader for incorporation 
this year. 

Most volatile herbicides, such as Sutan and Vernam, should be incorporated immedi- 
ately after application. The Treflan label allows an 8-hour delay, but the sooner 
the herbicide is incorporated the better. Lasso and AAtrex can be incorporated, 
but incorporation is not necessary unless yellow nutsedge is a major problem. 

ORGANIC MATTER AND HERBICIDE RATE 

Herbicide rates vary with the texture and organic matter content of the soil. Her- 
bicides most affected by organic matter content include: atrazine (AAtrex), sima- 
zine (Princep) , linuron (Lorox) , trifluralin (Treflan) , and nitralin (Planavin) , 
as well as combination products such as linuron/propachlor (Londax) and 
propachlor/atrazine (Ramrod/atrazine) . 

You can estimate organic matter content with the "Color Chart for Estimating Or- 
ganic Matter in Mineral Soils in Illinois" (AG- 1941) , and Fact Sheet SP-36 "Average 
Organic Matter Content in Illinois Soil Types." Both guides are available from 
your county Extension adviser or from the U. of I. Department of Agronomy. Or- 
ganic matter content is also available from some soil test reports. 

The "1971 Weed Control Guide"- -also available from county Extension offices --has 
suggested rates for herbicides and can be used as a guideline. 

Herbicides such as linuron (Lorox) and nitralin (Planavin) are not recommended 
for soils that contain more than 3- to 4-percent organic matter. Other herbicides 
such as propachlor (Ramrod) do not perform as satisfactorily on soils with low 
organic matter content. 



PLANT diseases 



WINTER INJURY TO ALFALFA AND CLOVER 






Several alfalfa and red clover samples received by the Extension Plant Pathologists 
in the Department of Plant Pathology show crowns that are soft (easily broken) and 
usually dark to reddish-brown when split apart. The center of the primary root may 
also appear discolored and hollow, and the walls of the hollowed root may appear 
"honeycombed." These symptoms indicate winter injury followed by attack by one or 
more crown and root-rotting fungi. 

Four types of winter injury are commonly recognized: 

1. Heaving- -Alternate freezing and thawing, especially where fields were wet dur- 
ing the winter, can lift the plant from the soil and separate it from the side 
roots. 

2. Low- temperature injury --This kind of injury usually occurs when unadapted va- 
rieties are planted. Application of fertilizers, especially nitrogen, and cut- 
ting or grazing in late fall may aggravate the problem. 

5. Frost injury - -Frosts that occur after plants have started vigorous spring 
growth can leave fields brown. However, unless complications develop, plants 
should recover rapidly in warm weather. 

4. Ice sheets --Ice sheets cause the most serious type of winter injury. Entire 
stands can be lost to ice-sheet formations caused by sleet storms or water 
from rain or melting snow that has frozen. Varieties that are resistant to 
cold injury are generally most resistant to ice -sheet injury. 

Winter injury often leaves plant tissue with deep cracks or other wounds that act 
as entry points for plant -pathogenic fungi and bacteria. 

Controls include: 

1. Sow seed of adapted varieties that are certified disease- free and high yield- 
ing. 

2. Practice balanced soil fertility. Avoid overfertilization as well as late- 
summer or fall application of fertilizer. 

3. Avoid overgrazing and "short clipping." These practices cut down food re- 
serves and lessen the chances for winter survival. 

Further information can be obtained from your county Extension adviser or by 
writing to the University of Illinois Department of Plant Pathology, Urbana, Il- 
linois 61801. Ask for Report on Plant Diseases, No. 302, "Roof and Crown Dis- 
eases of Alfalfa," or RPD No. 304, "Root and Crown Diseases of Clover." 

LEAF-SPOTTING DISEASES OF ALFALFA 

Leaf spotting of alfalfa can cause loss of vigor and reduction in hay quality and 
yield. Wet spring weather increases the chances of 1 leaf spotting. 

1. Common leaf spot --Symptoms of this disease are small, circular, dark-brown 
spots about 1/16 inch in diameter on alfalfa leaflets. First-year plants may 



be weakened or stunted, but little damage occurs. Severe infections may cause 
premature leaf drop. This disease is not seed-borne. 

2. Yellow leaf blotch- -This disease shows up as yellowing of the leaf margins or 
along the veins. As the disease progresses, the yellow areas turn orange and 
small dark dots (fungus fruiting bodies) may be seen. 

3. Pseudoplea spot- -Small, sunken, irregular black spots form on the leaflets. 
These areas become black-dotted and sunken with gray centers and reddish-brown 
margins as the disease advances. 

4. Stemphylium leaf spot - -The fungus that causes this disease can overwinter on 
seed as well as in plant debris. Early infections appear as small, irregular, 
dark-brown, sunken spots. Later the spots enlarge, become target-like and are 
often surrounded by a yellow "halo." Infected leaves often turn yellow and 
may fall prematurely. 

Control: Losses from common leaf spot, yellow leaf blotch, Pseudoplea spot, and 
Stemphylium leaf spot can be limited by good cultural practices. Sow certified 
disease- free seed, cut infected stands in early bloom before leaves fall, and grow 
high-yielding, resistant varieties. 

More information can be obtained from your county Extension adviser. Or write to 
the University of Illinois Department of Plant Pathology, Urbana, Illinois 61801. 
Ask for RPD No. 301, "Leaf and Stem Diseases of Alfalfa." 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 

Read and follow the precautions but also be sure to put pesticides, and all poi- 
sonous materials for that matter, out of the reach of small children and people 
who are not responsible for their actions. 

This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , 
College of Agriculture , University of Illinois at U rbana- Champaign , and the Il- 
linois Natural History Survey. 

PLANT PATHOLOGY: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 

WEEDS: Ellery Knake and Marshal McGlamery , Department of Agronomy . 

AG COMMUNICATIONS: Ray Woodis . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



Ifa I 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMvlEDIATE RELEASE 



No. 5, April 30, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and oommeroial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



INSECTS 



FORAGE INSECTS 






Alfalfa weevils developed very fast this past week, and feeding damage is notice- 
able in fields within the southern third to half of the state. Infestations appear 
to be heavier than last year. However, wasp parasites of weevil larvae are increas- 
ing, and they will help curb the weevil populations. 

Fields needing treatment were observed as far north as Highway 16. Between Highway 
16 and Highway 136, some fields may need treatment this week. It will be another 
one to three weeks before infestations are serious north of Highway 136. 

In the extreme southern section (south of Highway 13) , damage is already severe and 
the best time for insecticide treatment is past. Consider cutting and removing the 
hay and spraying the new growth, if needed. Larvae are already beginning to pupate 
and wasp parasites are taking their toll in this area. Larval populations have prob- 
ably already reached their peak, and will now decline slowly during the next three 
to four weeks. 

There is considerable variation in weevil populations between different areas and 
fields. So check each field separately to make judgments. Do not apply insecti- 
cides unless they are needed. Treatment with an insecticide is justified when 25 
percent of the tips show feeding and the field is more than two weeks from harvest. 

The insecticide recommendations are: 



Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azin- 
phosmethyl (Guthion) for good results. Use azinphosmethyl only once per cutting. 
Do not harvest for 15 days after treatment with methyl parathion, or 16 days for 
azinphosmethyl. Wear protective clothing. 

Persons not equipped with protective clothing . Use: (1) Imidan at 1 pound per 
acre; (2) a mixture of 3/4 pound of malathion and 3/4 pound of methoxychlor per 
acre; (3) a mixture containing at least 1/2 pound of diazinon and 1 pound of 
methoxychlor per acre; or (4) 1-1/4 pounds of malathion per acre on days when 
air temperatures will be above 60° F. for several hours after application. Do 
not harvest for 7 days after treatment with Imidan, methoxychlor, diazinon, or 
mixtures of them. There is no waiting period for malathion. Do not apply Imidan 
more than once per cutting. 



3. Using ground equipment . Apply a minimum of 20 gallons of finished spray per 
acre, or 4 gallons by air. 

SPECIAL NOTE: Some spray burn was noticed this week from methyl parathion and 
malathion. The burn is associated with rapid growth, and occurs mostly in the 
more- luxuriant stands. This may be due to the elimination of the weevil larvae 
by the insecticide and the resulting spurt of growth or may be caused by other 
factors, such as cold weather after the treatment. Other phosphate insecticides 
may also cause spray burn. Generally speaking, the burn is not serious; but 
occasionally, yields are adversely affected. The burn appears two to three days 
after spraying as white spots on the leaves. Some cold injury that resembles 
spray burn was also observed. 

Meadow spittlebugs are just beginning to hatch in the northern half of Illinois. 
The hatch is well underway in the southern half of the state, where occasional 
froth masses are apparent. The heaviest overwintering concentration of spittle- 
bug eggs is in the northern tier of counties and in the McLean County area of 
central Illinois. These tiny, yellow- to- orange nymphs are down low behind the 
leaf sheaths. Soon, they will move higher up on the plants and form froth masses. 
Control with insecticides has not usually been profitable for several years. How- 
ever, if there is more than one spittlebug nymph per stem (not per plant), treat- 
ment is justified. Use 1/2 pound of methoxychlor per acre, and wait seven days 
before harvesting or pasturing. 

CORN INSECTS 

Slender seed-corn beetles and striped seed-corn beetles are now present in fields 
of corn stubble. These beetles eat holes in the germinating corn seed and cut 
small sprouts. The severity of the problem will depend on weather conditions dur- 
ing the planting period. Cool weather and slow germination will enhance the like- 
lihood of damage. Warm weather with adequate moisture, which will produce faster 
germination, will lower the chances for injury. 

Diazinon as a dust applied to the seed corn will protect against the slender and 
striped seed-corn beetles. Also, the phosphate insecticides [diazinon, Dasanit, 
Dyfonate, and phorate (Thimet) ] applied as granules in a 7- inch band just ahead 
of the press wheel will provide control. 

Flea beetles can cause rapid and serious injury to small, newly emerging corn plants. 
These tiny, shiny black beetles jump readily when disturbed. They eat the green 
from the plant leaf, leaving white scratch marks. Damaged plants will turn white, 
and are sometimes killed. Carbaryl (Sevin) at 3/4 pound or toxaphene at 1-1/2 
pounds of actual chemical per acre as a band spray over the row gives effective 
control. 

Carbaryl is preferred for use on dairy farms. To prevent additional flea beetles 
from moving into the corn, treat grassy areas bordering the field. Do not use 
carbaryl near beehives or toxaphene near fish-bearing waters. 

CORN INSECTS 

A few scattered reports have been received of wireworms damaging corn. These worms 
will attack both the germinating seed and underground portion of the stem. If 



replanting is necessary, use one of the phosphate insecticides (diazinon at 2 
pounds per acre, Dasanit, Dyfonate, or Thimet at 1 pound per acre) as granules in 
a 7- inch band just ahead of the press wheel. These insecticides will control the 
small wireworms , but may not control the larger ones . 

LIVESTOCK INSECTS 

Horn flies appeared for the first time on cattle in pasture this past week in 
southern sections. Populations are still light but they could build up to eco- 
nomic levels (50-100 or more per animal) within the next few weeks. 

Face flies have been observed in light numbers on pastured cattle near wooded 
areas in the central section. These adult flies spent the winter in homes, barns, 
sheds and probably in protected areas in woods, and they are now laying eggs for 
the first generation of flies. Before the new spring adults emerge in late May 
and early June, the flies now present will die. Therefore, during mid-May few, 
if any, face flies will be present. 

HOMEOWNER INSECTS 

Spider mites are building up on junipers, and some damage has been reported. The 
mites cause a russetting and browning of the foliage. To detect mites, strike a 
branch sharply with one hand while holding a white dish or piece of paper under 
the branch with the other. The spider mites appear as small, moving black specks 
on a white surface. For control, apply dicofol (Kelthane 18.5-percent liquid con- 
centrate) at 2 teaspoons ful per gallon of water or 1-1/2 teaspoons ful of 25-percent 
wettable powder chlorobenzilate per gallon of water. Repeat treatments may be 
needed. 

Eastern tent caterpillars are feeding on a variety of trees --especially on wild 
cherry, willow, and fruit trees. These insects spin webs in the tree crotches 
and feed on the foliage outside their web nests. Some small, wild cherry trees 
were already completely stripped of their leaves this week. If control is needed, 
apply a spray containing cabaryl (Sevin) or malathion. For carbaryl, mix 2 table- 
spoons of the 50-percent wettable powder per gallon of water. For malathion, mix 
2 teaspoons of the 50- to 75-percent liquid concentrate per gallon of water. 

The tick season is getting into full swing. The peak period of activity is in May 
and June. Campers, picnickers, hikers, fishermen, and berry pickers are the ones 
most often attacked. Ticks cling to vegetation along paths in brushy places and 
the woods. They lie in wait, ready to attach themselves to a passing animal or 
man. A favorite place for feeding on a person is at the base of the head around 
the hairline. Certain ticks can transmit Rocky Mountain spotted fever to man. 
Occasional cases of this disease have been reported in Illinois. 

When entering areas that may be infested with ticks, use a repellent on socks, 
pant cuffs, and exposed parts of the body. DEET (diethyltoluamide) is a reason- 
ably effective tick-repellent. It also works well against mosquitoes. To con- 
trol ticks in such places as home yards, parks, lay grounds, or around the summer 
cabins, spray the grass, shrubs, and flowers with malathion or carbaryl (Sevin). 
Do not apply malathion to canaert red cedar, or carbaryl to Boston Ivy. 

You can prevent ants, spiders, waterbugs, centipedes, crickets, and other insects 
from entering your home by spraying the outside foundation wall with a 1-percent 



-4- 

emulsion of chlordane in water. Purchase chlordane as a liquid concentrate. Mix 
it with water to the proper strength. A half pint (8 ounces or 1 cup) of 45-percent 
chlordane in three gallons of water gives a 1 -percent emulsion. Spray the founda- 
tion wall from the soil to the sill area, or along the outer wall, for a distance 
of about a foot above the soil to the point of runoff. In addition, spray the ex- 
pansion joints along porches and steps, and along the edges of sidewalks and drive- 
ways. In homes with a crawl space, spray the inside wall and any supporting pillars. 
Do not spray directly onto shrubbery or flowers. The oil solvent in the spray may 
burn the tender foliage of some plants. Plan on repeating the treatment two or three 
times this summer. 

Three gallons of finished spray should do for the average house. The need for using 
insecticides inside the home will be greatly reduced by the kind of spraying rec- 
ommended above, under the house and around its perimeter. 



WEEDS 

DRY WEATHER AND HERBICIDE FAILURE 

The dry weather this spring has caused concern about the possibility of herbicide 
failure. If you applied a herbicide but weeds appear because the herbicide is not 
working, use a rotary hoe to control small weeds. 

Do not wait for rain to see whether the herbicide will work. Small weeds are easier 
to control with a rotary hoe than larger ones. The minimal incorporation of the her- 
bicide with a rotary hoe will not retard herbicidal action. It may improve it. 

CONTROLLING JOHNSONGRASS 

Johnsongrass is a perennial plant that is difficult to control. Seedlings cause 
the main problem in most fields, but there is also some "old grass" that sprouts 
from rhizomes. If you did not control that last summer or fall, there is still 
time this spring. 

Follow these tips: 

1. Let the Johnsongrass grow about a foot high before tilling. 

2. Spray 5 to 7 pounds of Dowpon in 30 to 40 gallons of water per acre. 

3. Wait 3 to 5 days after spraying, then plow or disk. 

4. Wait 1 to 3 weeks after tillage to plant corn or soybeans. Wait at least 
2-1/2 weeks before planting sorghum. 

To get the best control of seedling Johnsongrass , use a preemergence or preplant 
herbicide- -Tref Ian, Planavin or Vernam in soybeans, Eptam or Sutan in corn. There 
is no herbicide for control of Johnsongrass seedlings in grain sorghum. The same 
treatments will also control wild cane in corn and soybeans. 

NEW TANK-MIX CLEARANCES 

Federal registration has been given for a tank-mix of Preemerge (dinitro) plus 
Lasso or Preemerge plus Amiben. Both are for preemergence or early postemergence 



-5- 

weed control in soybeans. The rate of Preemerge is 4 to 6 quarts per acre when 
used in preemergence applications, or 2 to 5 quarts per acre in early postemer- 
gence treatments. Use the lower rate if temperature is above 75° F. In the com- 
bination, use the normal rate of Amiben or Lasso. 

FALL PANICUM CONTROL 

Fall panicum is a grass weed that continues to germinate late in the season. Pres- 
ent practices --including earlier planting and "lay-by" plus a greater dependence 
on chemicals and a reduction in the amount of mechanical tillage- -help create fa- 
vorable conditions for late-emerging weeds, especially in wide-row corn where the 
shade is late in coming between the rows. 

Fall panicum is a problem throughout Illinois, but the worst problem is in southern 
Illinois because of wider rows, a longer growing season and greater dependence on 
atrazine (AAtrex) as a herbicide. Fall panicum is especially a problem in zero- 
tillage corn. 

Simazine (Princep) gives better control than atrazine (AAtrex) of late-emerging 
grasses, such as fall panicum and crabgrass. Alachlor (Lasso) and butylate (Sutan) 
are two other herbicides that have enough persistence to maintain control of late- 
emerging grasses. Many people combine atrazine or simazine with Lasso or Sutan for 
controlling broadleaved weeds. But remember that it is necessary to incorporate 
Sutan soon after application. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , Col- 
lege of Agriculture, University of Illinois at Urbana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: Ellery Knake and Marshal McG lamer y , Department of Agronomy. 

AG COMMUNICATIONS: Ray Woodis. 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



vi 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PL ANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 6, May 7, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
■plant disease situation (fruit and oommeroial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. lA/^y 



INSECTS 



JUL 2 



lagj 



FORAGE INSECTS 






"■UNOJS! 



Alfalfa weevils . Development in the central section of the state has probably been 
slowed down by the cool weather, but many alfalfa fields between Highway 13 and 16 
are being damaged. The number of fields needing treatment is greater in this area 
and to the south of it than last year. Wasp parasites are also present in this area, 
with the percentage of parasitism of larvae ranging from 20 in Pulaski County to 60 
in a field in Lawrence County. 

The weevil population should have reached its peak this week in the area south of 
Highway 460, with parasites reducing the population. In that area, it would be 
best to cut the alfalfa, remove it, and treat the new growth- -if needed. 

Watch the fields between Highways 16 and 136 for weevil damage next week. 

There is a considerable variation in weevil population between different areas and 
fields. Check each field separately to make judgments. Do not apply insecticides 
unless they are needed. Treatment with an insecticide is justified when 25 percent 
of the tips show feeding and the field is more than two weeks from harvest. 

The insecticide recommendations are: 

1 - Commercial applicators . Apply 1/2 pound per acre of methyl parathion or azin- 
phosmethyl (Guthion) for good results. Use azinphosmethyl only once per cut- 
ting. Do not harvest for 15 days after treatment with methyl parathion, or 
16 days for azinphosmethyl. Wear protective clothing. 

2- Persons not equipped with protective clothing . Use: (1) Imidan at 1 pound 
per acre; [2] a mixture of 3/4 pound of malathion and 3/4 pound of methoxychlor 
per acre; (3) a mixture containing at least 1/2 pound of diazinon and 1 pound 
of methoxychlor per acre; or (4) 1-1/4 pounds of malathion per acre on days 
when air temperatures will be above 60° F. for several hours after application. 
Do not harvest for 7 days after treatment with Imidan, methoxychlor, diazinon, 
or mixtures of them. There is no waiting period for malathion. Do not apply 
Imidan more than once per cutting. 

3 - Using ground equipment . Apply a minimum of 20 gallons of finished spray per 
acre, or 4 gallons by air. 



CORN INSECTS 

White grubs . They were reported feeding on the roots of early corn in Sangamon 
County this week. Populations ranged from 2 to 25 per yard of row, with an 
average of 12. There are many species of white grubs. They usually have a three- 
year life cycle. 

The grubs in the Sangamon County field were a different species than the ones that 
caused a problem in soybeans in 1965 and again in 1968. After the corn is up, con- 
trolling this grub is difficult. An application of aldrin or heptachlor using a 
rotary hoe and followed by an inch of rain will help. There is no control avail- 
able for soybeans. We have no information on the newer insecticides as a control 
for this pest. 

Leafhoppers . They are now prevalent on corn, particularly along grass -sod areas 
such as waterways in southern Illinois. Ordinarily, this pest does not seriously 
damage the corn, which means that chemical control would not be profitable. 

Corn flea beetles . These are very numerous in corn fields in the central and 
southern sections of the state. There is an average of 6 to 10 beetles per plant 
in some stands of corn. The tiny, shiny black, corn flea beetles --which jump when 
disturbed- -feed on the surface of the corn leaf, leaving scratch marks and often 
causing the leaves to turn white or silvery. The plants are sometimes killed. 

If these beetles are numerous and damage is severe, apply 3/4 pound of carbaryl 
(Sevin) --preferred on dairy farms- -or 1-1/2 pounds of toxaphene per acre as a band 
spray over the row. The grassy areas in and around the field, such as waterways 
and fence rows , should also be treated to prevent additional beetles from moving 
into the field. Do not use carbaryl near bee hives or toxaphene near fish-bearing 
waters . 

Insect reports this week were received from Denver Corn, Sangamon County Extension 
Adviser; Robert Frank, Jackson County Extension Adviser; and Robert Schmerbauch, 
Wayne County Extension Adviser. 

HOMEOWNER INSECTS 

Eastern tent caterpillars . They have severely defoliated trees in some areas of 
southern Illinois. These dark-colored worms with a white stripe down the back 
spin their webs in the crotches and on the limbs and trunks of trees , especially 
wild cherry. Many caterpillars are now full grown (2 inches long) , and are 
spinning cocoons- -on the tree or some nearby structure. 

If most of the Eastern tent caterpillars are less than 1-1/2 inches long, they 
can be controlled with carbaryl (Sevin) or malathion, applied as a spray. Do 
not treat if larvae are full-grown or are pupating. 

Oystershell scale . These eggs are beginning to hatch in southern and central sec- 
tions of Illinois. Another two weeks will be required to complete the hatch. These 
brownish-gray scales, about 1/8 inch long, are often found on lilacs, dogwoods, 
birches, and soft maples, as well as other shrubs and trees. The newly hatched 
crawlers move to new areas on the bark and set up housekeeping by constructing a 
scale over their body. 



-3- 

These crawlers can be controlled by a thorough application of a spray containing 
malathion or diazinon. If malathion is used, mix two teaspoons of 50- to 57- 
percent liquid concentrate in each gallon of spray. Diazinon should be mixed, 
using 2 teaspoons of the 25-percent liquid concentrate per gallon of spray. 



Pine sawf lies . 

in the southern section of 



They are hatching and beginning to feed on the needles of pine 
trees in the southern section of the state. These black-headed, grayish-green 
caterpillars strip the needles from the red, white, jack, and other pine spe- 
cies. Christmas tree plantings, as well as other pine plantings, should be 
observed at regular intervals during the next three weeks for this insect. 
Spraying with carbaryl (Sevin) will provide control. 

weeds 

TOXICITY AND THE LABEL 

Most pesticide labels do not directly state the oral or dermal toxicity of the ma- 
terial, but certain key words on the label indicate the relative toxicity. Toxicity 
is the inherent capacity of a substance to cause injury or death. 

The words "DANGER" or "POISON" and the skull-and-crossbones symbol are required on 
the label if the material is highly toxic (see table below). The word "WARNING" 
is required for moderately toxic materials. "CAUTION" is required for slightly 
toxic materials. All labels must bear the statement "Keep out of the reach of 
children." 

Toxicity Classes 



Route 



Term 



Oral LD50 



Dermal LD50 



Probable lethal 
oral dose for man 



Highly toxic 0-50 0-200 1 tablespoon to 1 teaspoon 

Moderately toxic 50-500 200-1,000 1 teaspoon to 2 tablespoons 

Slightly toxic 500-5,000 1,000-2,000 2 teaspoons to 1 pint 

Practically non-toxic. .5,000-15,000 2,000-20,000 1 pint to 1 quart 

Relatively harmless. . . .more than more than more than 1 quart 

15,000 20,000 

Remember toxicity is only one factor to consider when using pesticides. Always 
read and heed the label. 



PLANT DISEASES 



SOUTHERN CORN LEAF BLIGHT 

None of the corn- seedling samples received so far at the Plant Disease Clinic 
have been infected with the southern corn leaf blight (SCLB) . Most problems were 
caused by (1) cold damage- -frost and low temperatures; (2) mechanical injury- - 
wind and soil particle abrasion; (3) common seedling blights, such as Diplodia 
and Gibberella; or (4) some flea beetle activity. 

SCLB infection symptoms on susceptible corn seedlings will appear first as 
scattered, tiny, circular spots. These will usually have tan centers and a 



reddish-brown border. Under favorable conditions (warm, humid weather) , these 
tiny spots will enlarge within 7 to 10 days after they become visible on the leaf. 
It takes much longer during dry, cool weather. 

One way to check for the organism that causes southern corn leaf blight is to 
place infected leaf sections between soaking-wet paper towels. If masses of dark 
fungus spores are produced within 1 to 5 days, this indicates the possible pres- 
ence of Helminthosporium maydis. However, further examination is necessary for 
positive identification. 

Chlorotic (yellow) spots, wrinkled leaves, streaks, or large bleached areas do 
not necessarily indicate the presence of southern corn leaf blight. Remember, 
that moisture must be on the leaf surface for at least 6 hours , along with viable 
spores, before an infection can occur. 

QUARANTINE ON SOYBEAN CYST NEMATODE REVOKED 

The USDA will revoke the Federal soybean cyst nematode quarantine, effective June 
50, 1971. That action will remove Federal regulations from all states now under 
quarantine- -Arkansas, Florida, Illinois, Indiana, Kentucky, Louisiana, Mississippi, 
North Carolina, Tennessee, and Virginia. The nematode can be controlled with a 
crop rotation system that does not include snap and adzuki beans, lespedeza, com- 
mon vetch, or lupines. Resistant varieties may also be used in some areas, such as 
in southern Illinois. 

For more information about the soybean cyst nematode, read Report on Plant Diseases 
No. 501 (revised) "The Soybean Cyst Nematode Problem." For a copy, contact the De- 
partment of Plant Pathology (218 Mumford Hall, Urbana, Illinois 61801) or from your 
county Extension Adviser in Agriculture. 

LOOSE SOD 

Sod root isolations from several specimens received by the Plant Disease Clinic do 
not show the presence of any pathogen. The root systems look stunted and discolored,' 
and the upper parts of the plants are dead or dying. Sod showing these symptoms can 
usually be easily lifted from the soil because of the lack of root penetration into 
the soil below. The symptoms will be accentuated by moisture deficiency. 

There are eight basic steps for putting in a lawn, seed or sod, that may help avoid 
the problem. 

Before planting: 

1. Remove debris--such as tin, construction lumber, large rocks, plaster, or 
pieces of cement. 

2. Make sure the lawn is properly graded. 

5. Find out if sub surface tile drainage is needed. 

4. Remove any large deposits of poor-quality soil that may be covering the top- 
soil. 

5. Improve soil conditions, if necessary, by adding topsoil, sand, peat, or other 
organic matter. These materials change the soil conditions, but are expensive. 



6. Test the soil to determine its acidity or alkalinity, as well as the relative 
amounts of nutrients present. 

7. Work the soil to break-up clods and insure a uniform soil texture. 

8. Incorporate a fertilizer with a high content of potassium and phosphorus into 
the top 6 to 7 inches of soil. 

If "the sod is loose and dying and there is no apparent cause (covered debris , flood- 
ing, drought, and so on), the problem may be corrected. A good watering schedule 
should be combined with the application of an adequate fertilization program. Use 
1-1/2 to 2 pounds of nitrogen per 1,000 square feet of lawn in the early spring or 
late fall. 

Starting a Lawn and Keeping a Lawn, Circulars 963 and 982, respectively, are avail- 
able at the county Extension office or from the Office of Agricultural Publications, 
123 Mumford Hall, Urbana, Illinois 61801. These publications cover choosing seed or 
sod; grass varieties; fertilization; mowing; watering; plus insects, diseases, weeds, 
and other lawn pests. 

SOYBEAN SEED QUALITY 

Soybeans (especially from northern and central Illinois) received by the Illinois 
Crop Improvement Association are testing below the normal germination level this 
year. Low germination and quality may be caused by beans that are shriveled, sev- 
erely cracked, moldy, split, badly weathered, immature, purple-mottled, or stained 
gray or brown. Much of the reduction is caused by fungi such as those causing pod 
and stem blight and stem canker. Such fungi attack the weakened seed during ger- 
mination. 

Each year in Illinois, there is an effort by some chemical companies to promote 
fungicide seed treatment , with or without one of the necessary minor elements. It 
is not unusual to show a 10- to 20-percent increase in germination and stand by 
proper seed treatment. However, it is rare for fields planted with treated soy- 
beans to outyield untreated beans, because essentially the same yield is obtained 
whether the beans are spaced 1, 2, 3, 4, 5, or even 6 inches apart in the row. 

If you suspect you have low- germinating beans, have them tested. If germination 
is below 80 percent, do not use those beans for seed. It is best to buy certified 
seed of proven high quality. It usually does not pay to treat soybean seed if the 
quality if high- -above 80-percent germination . 

For more information, read Report on Plant Diseases No. 506, "Should Soybean Seed 
Be Treated?" Copies are available from the Department of Plant Pathology (215 Mum- 
ford Hall, Urbana, Illinois 61801) or from the county Extension office. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , 
College of Agriculture , University of Illinois at Urbana-Champaign , and the Il- 
linois Natural History Survey. 

WEEDS: Ellery Knake and Marshal McGlamery , Department of Agronomy. 



-6- 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 
AG COMMUNICATIONS: Ray Woodis. 

The information for this report was gathered by these people, staff members, county- 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 



M< / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 7, May 14, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and plant 
disease situation (fruit and commercial vegetables excepted) , along with suggested, ab- 
breviated control measures. Each individual should check his own fields to determine 
local conditions. 



INSECTS 



JUL 



FORAGE INSECTS 









Alfalfa weevils . These pests continue to damage alfalfa in the southern half of Illi- 
nois^ Fields needing treatment were observed as far north as Route 136 this week. 
Heavier populations were observed further north along the west side of the state than 
along the east. Feeding is evident north of Route 136. Treatments could be needed 
in some fields this week or next. 

In the southern third of Illinois, it would be best to cut the alfalfa, remove the 
hay, and spray the new growth if needed. Treat immediately if the new growth does 
not green-up in two or three days . 

In the central third of the state, many fields were treated this past week. Alfalfa 
is rapidly approaching the point of harvest. It might be best to consider cutting 
the crop, removing the hay, and spraying the new growth of the second crop. 

For the most part in the southern half of the state, alfalfa weevil larvae are pu- 
pating rapidly. Wasp parasites are prevalent and are helping reduce the number of 
larvae. New spring adults are beginning to emerge now. However, eggs are still 
hatching and damage can be expected for another two to three weeks. 

There is a considerable variation in weevil population between different areas and 
fields. Check each field separately to make judgments. Do not apply insecticides 
unless they are needed. Treatment with an insecticide is justified when 25 percent 
of the tips show feeding and the field is more than two weeks from harvest. 

The insecticide recommendations are: 



1. Co mmercial applicators . Apply 1/2 pound per acre of methyl parathion or azin- 
pHosmethyl (Guthion) for good results. Use azinphosmethyl only once per cut- 
ting. Do not harvest for 15 days after treatment with methyl parathion, or 

16 days for azinphosmethyl. Wear protective clothing. 

2. Persons not equipped with protective clothing . Use: (1) Imidan at 1 pound per 
acre; (2) a mixture of 3/4 pound of malathion and 3/4 pound of methoxychlor per 
acre; (3) a mixture containing at least 1/2 pound of diazinon and 1 pound of 
methoxychlor per acre; or (4) 1-1/4 pounds of malathion per acre on days when 
air temperatures will be above 60° F. for several hours after application. Do 
not harvest for 7 days after treatment with Imidan, methoxychlor, diazinon, or 



mixtures of them. There is no waiting period for malathion. Do not apply Imidan 
more than once per cutting. 

3. Using ground equipment . Apply a minimum of 20 gallons of finished spray per acre, 
or 4 gallons by air. 

CORN INSECTS 

Flea bettles. They continue to damage small, newly emerging corn plants. Once the 
corn is eight to ten inches tall, it can usually grow away from the beetle attack. 
The populations of flea beetles are higher than normal this year. These beetles can 
transmit Stewart's disease (bacterial wilt) to corn. The incidence of this disease 
is also expected to be higher than normal this year. Sweet corn varieties are much 
more susceptible to this wilt than the dent corn varieties. Drought conditions ac- 
centuate the disease condition. 

If flea beetles are numerous and damage is severe, apply 3/4 pound of carbaryl (Sevin)' 
preferred on dairy farms --or 1-1/2 pounds of toxaphene per acre as a band spray over 
the row. Grassy areas bordering fields should also be treated. Do not use carbaryl 
near bee hives or toxaphene near fish-bearing waters . 

Black cutworms . These moths have been flying for several weeks. Watch low, wet, or 
poorly drained spots in corn fields for damage. Cut or missing plants are a sign of 
cutworms. It will be to your advantage to detect cutworm damage early, while the 
worms are still small and easily killed. Be on the lookout during the next two to 
four weeks. 

You can control cutworms with a carbaryl (Sevin) bait application. A bait of 5-percent 
carbaryl on apple pomace applied broadcast at 20 pounds of the granules per acre is 
effective. A liquid bait (molasses or tractum) of carbaryl applied as a spray di- 
rected at the base of plants (1 pound per acre) or broadcast (2 pounds per acre) is 
also effective. No cultivation is needed when a carbaryl spray or granular bait is 
applied . Trichlorfon (Dylox) applied at 1 pound per acre in at least 20 gallons of 
water as a spray directed at the base of the plant will also provide control. Cover 
the trichlorfon spray band by throwing the soil at the base of the plants with a cul- 
tivator. 

Wireworms . Scattered reports of damaged corn have been received. Generally, the in- 
festations have not been too severe. If replanting is necessary, use one of the phos- 
phate insecticides (diazinon at 2 pounds per acre, Dasanit, Dyfonate, or Thimet at 
1 pound per acre) as granules in a 7-inch band just ahead of the press wheel. These 
insecticides will control the small wireworms, but may not control the longer ones. 

Corn borers . Pupation is well along in the southern section. It is just beginning 
in the central section. No pupation of borers has occurred in the northern section. 
It is too soon to make predictions. 

HOMEOWNER INSECTS 

Mites . Evergreens are being damaged, particularly junipers and cedars. Russeting 
and browning of foliage are a sign of mites. To check on the presence of the mites, 
hold a white piece of paper under a branch and strike the branch sharply. The mites 
will appear as small orange, grey, or black moving specks on the paper. A spray con- 
taining 2 teaspoons of dicofol ( Kel thane ) , an 18. 5 -percent liquid concentrate, or 
1-1/2 teaspoons of 25-percent wettable powder chlorobenzilate per gallon of water is 
effective. Repeated treatments may be needed. Malathion is only partially effective. 



Bronze birch borers . This is a pest of birch trees. The borers emerge as adults 
from under the bark of the upper limbs. Damage first appears in the tops of af- 
fected trees. The upper limbs may die as the borers tunnel under the bark, leav- 
ing raised rings around the limbs. These raised areas may show up on limbs that 
appear to be healthy, but are actually infested with borers. If borer symptoms 
are present, apply a treatment in late May in southern sections of Illinois and 
early June in northern ones. Spray the trunk and limbs thoroughly with dimeth- 
oate (Cygon or De-Fend) . Follow the directions on the container for mixing the 
spray. Repeat the treatment two weeks later. Keep the trees in a vigorous state 
of growth with adequate moisture and fertilization. 

Holly leaf miners . These can be found tunneling between the leaf tissues of many 
types of holly. They leave a yellowish mine, and will continue to damage the 
leaves if not controlled. Control is still possible. Use a spray of dimethoate 
(Cygon or De-Fend) . Follow the directions on the label for mixing the spray. 
Thorough coverage is important for effective results. Another spraying may be 
needed about the middle of June. 

Bagworms . Last year's bagworms should be picked from- evergreens and trees and 
burned. This is about as late as you can do this before the worms emerge. About 
half of these bags will have eggs inside. These eggs will hatch during the next 
two weeks in the southern section; about two to four weeks in the central part; 
and about four to six weeks in the northern area of Illinois. The more eggs you 
destroy now, the easier it will be to control the bagworms later. 

Clothes moths and carpet beetles . They are getting ready for a summer feast on im- 
properly stored woolens. A small hole chewed in a piece of clothing can destroy 
its entire value. To keep woolens safe from damage by these insects, follow these 
suggestions. 

1. Dry-clean or wash woolens and place them in clean, plastic storage bags or 
other insect- tight containers. 

2. Woolens that are not dry-cleaned or washed should be hung in bright sunlight 
for a full day and brushed thoroughly before storing. Pay particular attention 
to pocket interiors, cuffs, and folds when brushing. 

3. If the storage area is not insect-tight (as is true of most closets, trunks, 
and boxes) , vacuum the container thoroughly and spray all inside surfaces with 
a 0.5-percent diazinon mixture, applied from a pressurized spray can. 

4. Cedar-lined chests are usually insect-tight, but all fabrics need to be insect- 
free before storing. The cedar oil vapors destroy small larvae, but do not kill 
the larger ones. As added insurance in cedar chests, you can spray the inside 
surfaces as suggested above or use a fumigant material. Napthalene or PDB (para- 
dichlorobenzene) are commonly used- -in moth crystals, flakes, or balls. Use at 
least 1 pound of crystals, flakes, or balls for every 100 cubic feet of space. 

5. Woolens not placed in insect- free containers can be protected by treating in 
light amounts with a 0.5-percent diazinon mixture from a pressurized spray can, 
or by liberally moistening them with a fluoride-base fabric solution. This 
protection will last a year or more, unless the woolens are washed or dry-cleaned. 
Caution: Infants' clothing should be washed or dry-cleaned before use . 



Good housekeeping practices will help reduce the number of these insects. Clean 
the house frequently to prevent lint and hair from accumulating, especially around 
radiators, baseboards, heating vents, and closets, as well as beneath large furni- 
ture and other hard- to -get -at places. If such places become infested, a light ap- 
plication of a 0.5-percent diazinon spray will insure protection. 



WEEDS 



STALE-SEEDBED WEED CONTROL — A MODIFIED PIGGYBACK TREATMENT 

A stale seedbed is one that has been prepared before planting and then left undisturbec 
during planting. Treflan or Planavin is usually applied as a preplant treatment, whicl 
is incorporated sometime before planting. The weeds that were not controlled by the 
preplant chemical will emerge. At planting or shortly afterward, a contact herbicide, 
such as Lorox (linuron) , is applied to control the growing weeds, but the seedbed is 
not disturbed. 

Lorox (linuron) is the contact herbicide usually chosen, because it gives some residua] 
control in addition to the contact control. Adding a surfactant greatly enhances its 
contact action. Paraquat has also been tried, but some weeds still emerge after plant- 
ing; also, paraquat has no residual action. 

For drilled soybeans, the stale-seedbed concept is one of the most -promising practices 
for weed control. This concept is really a modified piggyback idea. Two herbicides 
are applied at different times. Lorox and Chloro-IPC have been cleared for use in a 
piggyback treatment with Treflan. Dynap--a combination of dinitro plus Alanap 
(naptalam) --is also being sold for use as an overlay treatment with a grass-control 
herbicide, such as Treflan. 

SOYBEAN HERBICIDE COMBINATIONS 

There are several new names in soybean herbicides. Many of these are herbicide com- 
binations that may provide control of more weeds or may permit use on a greater di- 
versity of soil types. Some of these combinations are: 

SHAMROX—Dacthal (DCPA) plus Lorox (linuron) 

SOLO- -Alanap (naptalam) plus Chloro-IPC (chlorpropham) 

NORABEN--Herban (norea) plus Amiben (chloramben) 

DYNAP- -dinitro (dinoseb) plus Alanap (naptalam) 

DYNARAM- -dinitro (dinoseb) plus Amiben (chloramben) 

AMILON- -Amiben (chloramben) plus Lorox (linuron) 

Tank mixes of Lasso (alachlor) with Lorox (linuron) or Chloro-IPC (chlorpropham) have 
also been cleared. Chloro-IPC is added primarily for smartweed control, while Lorox 
will control smartweed and many other broadleaf weeds for which Lasso does not provide 
adequate control. 



PLANT DISEASES 



STEWART'S DISEASE OR BACTERIAL WILT IN SWEET CORN 



The sum of the mean temperatures for December, 1970; January, 1971; and February, 
1971, was 108.7 in the Carbondale area (85.8 at Urbana) . This temperature index 
means that early season wilt may be destructive; also, that late-season leaf blight 
may be severe on susceptible sweet corn and seedling field corn. (See Report on 
Plant Diseases No. 907, Stewart's Disease or Bacterial Wilt of Sweet Corn, available 
from the UI Department of Plant Pathology, 218 Mumford Hall, Urbana, Illinois 61801. 

The bacterium that causes this disease [Xanthomonas stewartii) survives the winter 
in the bodies of corn flea beetles. Use an insecticide, as recommended by ento- 
mologists, to control the spread of the beetle. Dry weather favors feeding and re- 
production. Beetles feed on and scratch the leaf surface, permitting bacteria to 
enter through the wounds. 

Possible bacterial wilt infection would be indicated by premature tasseling; stunt- 
ing; narrow yellow-green streaks that turn tan; wilting during the daytime; wet, 
chocolate-brown cavities in the lower stalk region; or yellow oozing from the cut 
ends of the vascular tissue. 

Dent corn containing resistance to northern corn leaf blight is usually resistant 
to Stewart's disease after the four- or five- leaf stage. (See Report on Plant 
Diseases 201- -Stewart's Leaf Blight of Corn, available from the same source.) All 
sweet corn varieties are susceptible in the first leaf stage. Corn that was planted 
early may attract a large number of beetles, and susceptible seedlings may wilt rap- 
idly as the bacteria becomes systemic in the seedling and blocks water -conducting 
vessels. 

UPDATE ON THE SOUTHERN CORN LEAF BLIGHT 

To date, the southern corn leaf blight has been found only in Dade and Palm Beach 
Counties in southern Florida. Cold weather and lack of rainfall have prevented a 
build-up of the disease. In northern Florida, only normal (N) cytoplasm is planted. 
All sweet corn is sprayed with fungicides. 

The weekly Dixie Early Warning Service report, received May 10, shows no blight in 
South Carolina, North Carolina, Texas, or Alabama. In Mississippi and Kentucky, 
there were only traces in volunteer fields and on indicator plantings. 

Helminthosporium maydis , race T, appears to have overwintered in Illinois and sur- 
rounding states in the Corn Belt primarily on corn debris left above ground after 
last year's harvest. Where erosion control is not a problem, making a clean plow- 
down is a reasonable precaution. 

No H. maydis spores (conidia) have been caught in spore traps at Dixon Springs or 
Urbana-Champaign during the past two weeks (as of May 12) . 

AERIAL REMOTE -SENSING FOR SOUTHERN CORN LEAF BLIGHT IN ILLINOIS 

Several commercial companies plan to offer farmers infrared and color photographs 
of their fields (at a considerable cost) , in an attempt to detect the presence of 
southern corn leaf blight (SCLB) . However, in terms of disease control, the science 
of aerial remote -sensing is still in the observation phase, not the applied phase. 
Ground observers are still needed to correlate the aerial photographs. Only corn 



with SCLB on the middle and upper leaves was detected with infrared photography in 
1970 in an experiment conducted by the Laboratory for Applications of Remote Sensing 
(LARS) at Purdue University, in cooperation with Michigan State University. 

Currently, there is no experimental evidence that SCLB can be detected on infrared 
or other film before it can be seen on the ground by examining the plants. Color 
infrared film shows changes in the visible and near-infrared portion of the light 
wave spectrum- -not in the thermal (heat) portion where differences in plant temper- 
ature would be detectable. 

The Corn Blight Watch is being conducted by LARS, USDA, and NASA through the coopera- 
tion of Purdue University, the University of Illinois, Michigan State University, and 
others. It is an experiment . The object is to find out the extent to which diseases, 
such as southern corn leaf blight, and other stress conditions can be detected by 
using color infrared film; also, to differentiate such factors as drought stress or 
nitrogen deficiency, which may look similar to SCLB. 

Thirty-six counties are involved in the project in Illinois. The flight lines run 
from north to south in three strips-- (1) down the center of the state, (2) along 
the eastern edge, and (3) along the western edge. A training session for Extension 
advisers from the 36 counties will be held June 3 and 4 in Mumford Hall. Laying- 
out plot lines and other phases of obtaining "ground truth" will be explained. Ed 
Burns and Mai Shurtleff, University of Illinois Extension Plant Pathologists, will 
complete the program with a refresher on the disease problem. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows : 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , Col- 
lege of Agriculture , University of Illinois at Urbana-Champaign , and the Illinois 
Natural History Survey. 

WEEDS: Ellery Knake and Marshal McGlamery , Department of Agronomy . 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 

AG COMMUNICATIONS: Ray Woodis . 

The information for this report was gathered by these people, staff members, county 
Extension advisers, and others, in cooperation with the USDA Agricultural Research 
Service, Plant Pest Control Branch. 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




MSEC! WEED & PLANT DISEASE SURVEY BULLETIN 



WE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



JUL 



FOR IMMEDIATE RELEASE 



,"\- „ .^ 






No. 



, May 21, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



INSECTS 



SMALL GRAINS 

Armyworms . Six to nine armyworms per linear foot of drill row were found in a barley 
field in south- central Illinois this week. They were about 5/4 of an inch long, 
or approximately half grown. One or two worms per linear foot of drill row in 
wheat fields was common in the same area. Although these armyworms are still 
small, they will grow rapidly this week and will be noticeable in some fields. 
As yet, the situation is not alarming. 

To count armyworms in a grain field, look first in the thick, lodged spots. Army- 
worms will hide in the dead leaves and other trash at the base of the plants. If 
you find lots of worms, make a count in several places in the field and figure 
the average number of worms per foot of drill row. If you find no worms or only 
an occasional one in the thick or lodged spots, there is no need to look further. 
Chemical control is justified if there are 6 or more armyworms per foot of drill 
row, as an average over the field. 

An armyworm will eat 59 linear inches of wheat leaf in its life as a worm. How- 
ever, the leaf loss is usually not too important. So, do not become too alarmed 
if you find a few armyworms in a wheat field. They often feed only on tne leaves, 
and damage is usually minor. When they begin to cut off the wheat heads, however, 
damage can be severe. 

Eighty percent of the total food consumed by an armyworm during its lifetime is 
eaten during the last 20 percent of its life as a worm. Normally, you can wait 
until many of the armyworms are 5/4 of an inch long before starting treatment. 
This will give weather, armyworm diseases, and wasp and fly parasites a chance 
to kill many of them. Chemical control may not be necessary. However, once the 
worms are two- thirds to three- fourths grown and the population is high, chemical 
control may be needed. 

Applications of 1 to 1-1/4 pounds of malathion, 1 pound of trichlorfon (Dylox) , 
or 1-1/2 pounds toxaphene per acre will control armyworms. Do not feed forage or 
straw treated with toxaphene to dairy cattle, livestock being fattened for slaugh- 
ter, or poultry. After using trichlorfon, do not forage or feed the wheat within 



three days. There is no waiting period between the application of toxaphene and 
grain harvest; a week is required when applying malathion, 21 days for trichlorfon. 

Sawflies. Do not confuse the striped armyworms with the transparent yellow- to- 
green sawflies. An armyworm has five pairs of abdominal prolegs ; sawflies, six 
or more pairs. Sawflies were found in many wheat fields this week. They do not 
damage wheat plants enough to require control. 

CORN INSECTS 

Armyworms . This pest is also present in thick stands of grasses along roadsides, 
in pastures, and in some hay fields. They are larger than tnose found in small 
grain fields. These worms may soon migrate to adjacent fields with crops such 
as corn. When this happens, damage can be severe. In some cases the armyworms 
merely eat the leaves and the plant continues to grow; in others, they eat the 
plant down into the ground. 

Occasionally, armyworms are a serious problem in corn planted on grass sods or when 
rye has been plowed under in the spring. Before plowing, the moths deposit -eggs in 
the grass. Afterward, eggs hatch and the tiny worms feed on the grass. They soon 
move to the surface, where they will devour the small corn seedlings. 

Also watch fields in which no- till corn has been planted on grass sods. Armyworm 
moths deposit eggs in the grasses. The worms move up readily into the small corn. 

The insecticides for wheat can also be used on corn to control armyworms . 

Black cutworms . A few reports were received from western Illinois this week. Corn 
that is is cut off above the growing point will usually recuperate, but plants 
that are cut off below the growing point or heart are killed. In evaluating dam- 
age, take this possible regrowth factor into consideration before disking-up a 
field for replanting. 

However, as soon as you see cutworm damage, apply control measures. Control is 
much easier when the worms are small. 

You can control cutworms with an application of a carbaryl (Sevin) bait. A bait 
of 5-percent carbaryl on apple pomace applied broadcast at 20 pounds per acre is 
effective. A liquid bait, using molasses or Tractum with carbaryl, applied as a 
spray directed at the base of plants (1 pound per acre) or broadcast (2 pounds 
per acre) is also effective. Do not cultivate when a carbaryl spray or a granular 
bait is applied . Trichlorfon (Dylox) applied at 1 pound per acre in at least 20 
gallons of water as a spray directed at the base of the plant will also provide 
control. Cover the trichlorfon spray band by throwing the soil at the base of t 
the plants with a cultivator. Do not use sugar baits near bee hives. 

Yellow- striped armyworms . These dark- colored worms with yellow or white stripes 
on each side of the back are feeding on corn leaves. This feeding is usually of 
no consequence, so no not apply chemical control unless you feel that the popu- 
lation of worms is extremely high. 

Wireworms . Several fields of com were damaged by this pest this week. If re- 
planting is necessary, use one of the phosphate insecticides (diazinon at 2 pounds 
per acre or Dasanit, Dyfonate, or Thimet at 1 pound per acre) as granules in a 
7-inch band just ahead of the press wheel. These insecticides will control the 
small wireworms, but may not control the larger ones. 



-3- 

If damage has just begun and replanting is not yet indicated and the corn is big 
enough to cultivate, a cultivator application of phorate (Thimet) might be worth 
trying. This is only a gamble, however, in an attempt to save a stand in an emer- 
gency situation. The chemical needs to be concentrated at the base of the plant 
and covered with dirt by cultivation. A gentle rain immediately after application 
is helpful. 

European corn borers . Pupation is starting in central Illinois. From the stand- 
point of corn development, the borer is late; but by the calendar, it is almost 
on time. This may be a year to keep an eye on both first- and second- generation 
borers . 

FORAGE INSECTS 

Alfalfa weevils. The development of this pest has slowed down this week. Also, 
much of the alfalfa is being cut. 

Since the first cutting has either been taken off or soon will be, chemical con- 
trol is no longer recommended. Watch the new growth. If it does not green-up, 
check for alfalfa weevil larvae. If they are severely damaging the new shoots, 
use chemical control. See Report No. 7 for insecticide suggestions. 

Potato leafhoppers . These tiny, wedge-shaped, green pests can now be found as 
adults in alfalfa fields. They are abundant in some areas. These are the "green 
gnats" that are flying as the alfalfa is cut. They go to the new growth and de- 
posit eggs. The young, which look like the adults but are wingless, suck sap and 
also inject a toxin into the plant. This causes second-growth alfalfa to turn 
yellow or purple and to be severely stunted. 

It is too late to control this pest after the symptoms are apparent. If the 
adults are numerous, examine the new growth for tiny leafhoppers . If they are 
abundant, a malathion or methoxychlor spray will control them. 

HOMEOWNER INSECTS 

Chiggers . They annoy campers, hikers, picnickers, fishermen, berry pickers, and 
even homeowners in their own yard on occasion. These tiny mites cling to grasses 
and weeds, transferring to persons who happen to brush against them. When enter- 
ing areas that may be infested, use a repellent such as DEET (diethyltoluamide) . 
Apply the repellent on socks, pants, pant cuffs, as well as on exposed ankles and 
calves. Take a warm, soapy shower or bath as soon as possible after returning 
from a chigger- infested area. It takes the mites several hours to penetrate the 
skin; they can often be washed off before becoming imbedded. 

To reduce the number of chiggers in a home yard, spray malathion or diazinon 
lightly over the grass, low flowers, and shrubs. Do not apply diazinon to ferns 
or hibiscus, or malathion to cannaert red cedar. 

Fleas . Ordinarily they only annoy dogs and cats. But left uncontrolled, they can 
become a serious problem in a home or yard by late summer. In the worm (larva) 
stage, these fleas live in the bedding of dogs and cats, in rugs or upholstered 
furniture, and even in the dirt in flower and shrubbery beds. The worm stage is 
usually not noticed and is harmless, but adult fleas suck the blood of warm- 
blooded animals. Your dog or cat is a walking bait station for fleas. During 
the warm weather (May to October) , use a dust on them of either 4-percent 



-4- 

malathion or 5 -percent carbaryl (Sevin) . Treatments should also be made once or 
twice during the colder months (November to April) for added protection. 

Aphids . Many species are infesting trees and shrubs, such as apple and hawthorn 
trees and rose bushes. Damage caused by an aphid called a greenbug has also been 
found in bluegrass lawns in western Illinois. Greenbug damage appears as circular 
brown patches in the lawn, usually under or near a tree. Examine the grass blades 
on the outer edge of these patches for pale green plant lice or aphids. 

For control, apply a spray of either malathion or diazinon to the infested area. 
If malathion is used, mix 2 teaspoons of 50- to 57-percent liquid concentrate per 
gallon of water. For a diazinon spray, mix 2 teaspoons of the 25 -percent liquid 
concentrate per gallon of spray. Be sure to treat the healthy grass around the 
edge of the damaged area. 

Euonymous scales and pine needle scales . The hatch has begun, and these crawlers 
are moving onto new leaves and stems. Another name for euonymous is wintercreeper. 
Where these insects are a problem, apply malathion as a spray- -thoroughly cover- 
ing the bark and leaves. Make two to three applications on the infested shrubs. 
Space the applications about 10 days apart. The first application should be in 
mid-May in the southern part of the state, during the latter part of May in the 
central section, and in early June in the northern area. 



WEEDS 
WEED CONTROL IN SPRING OATS 

Weeds that germinate early, such as mustard, ragweed, smartweed, and lambsquarters , 
often cause problems in spring oats. These broadleaf weeds are easily controlled 
with 2,4-D or MCPA. MCPA is probably safer for use on legume underseedings, but 
it costs considerably more than 2,4-D. 

Use 2,4-D -amine where oats are undersown with a legume. Never use 2,4-D ester on 
a legume seeding. Apply 1/2 pint per acre of the 4-pounds-per-gallon form of 
2,4-D amine when the oats are 8 to 14 inches tall. 

The amine or ester forms of 2,4-DB (Butoxone or Butyrac) could also be used, but 
are more expensive than 2,4-D or MCPA. The rate is 1 to 2 quarts of 2,4-DB amine, 
or 5/4 to 1-1/2 quarts per acre of 2,4-DB ester- -applied when the small grain is 
4 to 8 inches tall. 

Where the small grain is not undersown with a legume, you can use higher rates of 
2,4-D amine or the 2,4-D ester. Use 1 pint per acre of 2,4-D amine or 2/5 pint 
per acre of 2,4-D ester (4 pounds per gallon). The application should be made 
when the oats are 4 to 12 inches tall. 

Banvel can also be used. It is particularly effective on smartweed and wild buck- 
wheat, but provides only weak control on mustards. Do not use Banvel when you 
have a legume underseeding. Apply 1/4 pint per acre of Banvel when the oats are 
in the two- to five- leaf stage. 

Some farmers seem to believe that 2,4-DB is the higher volatile butyl ester of 
2,4-D. This is not true. One farmer who bought 2,4-D ester and used it on al- 
falfa found out that there is quite a difference. 2,4-DB is the butyric acid form 



-5- 

(2,4-dichlorophenoxy-butyric acid). 2,4-D is the acetic acid form (2,4- 
dichlorophencocy-acetic acid). You can use 2,4-DB on legumes, but not 2,4-D 
butyl ester. 

PLANT DISEASES' 

FIRST SOUTHERN CORN LEAF BLIGHT FOUND 

The first positive case of southern corn leaf blight in Illinois was identified 
in the Plant Disease Clinic at the University of Illinois on May 19. The com 
sample came from a St. Clair County field, planted to a blend. The infected corn 
grows next to a grain bin where corn was shelled-out just before a rainy period. 

The disease has not spread in the field, and new leaves that have emerged since 
May 14 appear to be healthy. Because the known diseased area is small, patholo- 
gists suggested plowing-down the infected corn and replanting the area to re- 
sistant corn or soybeans. 

Southern corn leaf blight appears as small, oval or round spots on the leaves with 
a reddish-brown border . A yellowish halo may surround the border of some spots. 

The Plant Disease Clinic is receiving many corn specimens that show weather damage- 
mostly cold, hail, and wind-whipping. Yellowish spots, blotches, or streaks ap- 
pear in the leaves and later develop whitish or translucent centers. The tissue 
may also be torn on some spots. Scorched leaf tips are also common, sometimes 
associated with grayish areas in the leaf caused by the separation of the upper 
cuticle . 

SCLB spots can be distinguished from "weather spots" by the appearance of the def- 
inite, reddish-brown border. 

POWDERY MILDEW AND SEPTORIA LEAF BLOTCH OF WHEAT 

Powdery mildew and septoria leaf blotch are now showing up in small amounts where 
wheat stands are thick and the nitrogen fertilization rate is high. Mildew ap- 
pears as a whitish mold on the leaves, which may later turn "mealy" and brownish 
and in which black specks are formed (overwintering or oversummering fruiting 
bodies of the mildew fungus) . Septoria shows up as tan- to-brownish, oval-to- 
irregular blotches on the leaves. Later, the centers are sprinkled with black 
specks (fruiting bodies of the septoria fungus) . These diseases cause little 
damage and yield loss. In most years, powdery mildew and septoria can be found 
six to eight weeks earlier. Dry weather has held these diseases in check up to now. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman, and Tim Cooley , 
College of Agriculture, University of Illinois at Urbana-Champaign , and the Illi- 
nois Natural History Survey. 

WEEDS: Ellery Knake and Marshal McGlamery , Department of Agronomy . 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology - 

AG COMMUNICATIONS: Ray Woodis . 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



Vv 7 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PL ANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 9, May 28, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
■plant disease situation (fruit and commercial vegetables excepted) , along with 
suggested, abbreviated control measures . Each individual should check his own 
fields to determine local conditions. 



INSECTS 















CORN INSECTS 



Black cutworms. More reports of damage were received this week from several sec- 
tions, mostly in western Illinois. So far, the damage is confined to a relatively 
few cornfields , but is severe. The size of worms ranges from a half inch or less 
to almost two inches in length. Worms that are one-half to one inch long will 
continue to feed for another week to ten days. When the worms reach two inches 
in size, feeding is virtually completed and pupation will occur shortly. 

Cornfields should be carefully examined now for cut or missing plants --signs that 
cutworms are at work. Damage has been observed on hillsides as well as low, wet 
areas in fields. 



If damage is apparent, corn that is cut off above the growing point will usually 
recuperate, but plants cut off below the growing point are killed. If the corn 
is small, (2 to 4 inches high), cutting generally occurs above the growing point. 
About half of these plants could be expected to recover. Take this possible re- 
growth factor into consideration before disking-up a field and replanting. Im- 
mediate treatment is needed if many of the worms are less than an inch long and 
plants are being cut off below the growing point. 

For emergency control of cutworms, consider using one of the following treatments; 

1. A pellet- like bait of 5-percent carbaryl (Sevin) on apple pomace, applied 
broadcast at 20 pounds per acre with ground equipment or from the air. Do 
not cover by cultivation . 

2. A liquid bait using molasses or Tractum with carbaryl, applied as a spray 
directed as a band over the plants or at their base at the rate of 2 pounds 
per acre" ! The best coverage will be obtained with 20 gallons of water and 1 
or 2 quarts of molasses per acre. Do not cultivate immediately; but if the 
soil is dry, covering the carbaryl -molasses spray by cultivation may improve 
control. Do not use the sugar baits near bee hives. 

3. Trichlorfon (Dylox) , applied at 1 pound per acre in at least 20 gallons of 
water as a spray directed at the base of the plant, will also provide con- 
trol. Cover the trichlorfon spray band by throwing the soil at the base of 
the plants with a cultivator. 



This past week, varying control of cutworms was obtained by using the carbaryl- 
molasses spray. Some results have been good- -others fair to poor. In some in- 
stances, several days passed before control was evident. Emergency cutworm con- 
trol has always been erratic and tough to achieve. This year is no exception. 
Several factors appear to be responsible for the poor results. Where the soil 
was dry, the worms fed beneath the soil surface and did not come in contact with 
the toxicant. Where the soil surface was moist, the cutworms fed on or near the 
surface and were killed by the chemical. 

The need for applying emergency treatments will vary from field to field. If the 
field is too wet thus preventing ground application of an insecticide, an aerial 
application of the 5-percent apple pomace bait can be used at the rate of 20 
pounds per acre. 

If replanting is necessary, the cutworms may still be present when the corn comes 
up. Dyfonate granules at the rate of 2 pounds of actual ingredient per acre, 
banded ahead of the planter press wheel, will give control. When replanting 
without disking-out the plants remaining in the old stand, follow the replanting 
immediately with a carbaryl -molasses spray over the row at 2 pounds per acre. 

Of the cutworm complaints received, about half of the damaged cornfields have 
been treated with a row or broadcast application of aldrin or heptachlor at 
planting time. 

Wireworms . More reports of damage to corn by this pest were received this week. 
If replanting is necessary, use one of the organic phosphate insecticides- -Thimet, 
Dyfonate, and Dasanit at 1 pound or diazinon at 2 pounds per acre. These will 
control small wireworms, but may not control the large ones. A rain after appli- 
cation is helpful. We have had several reports of wireworm- control failure with 
row treatments of aldrin, heptachlor, and chlordane. 

European corn borers . Pupation of overwintering corn borers is 100 percent com- 
plete in southern Illinois, where moth- emergence has started and egg-laying is 
underway. Pupation is 65-percent complete in the central sections of the state, 
and moth- emergence is just starting. Pupation is just beginning in northern Il- 
linois. 

True armyworms . More reports have been received of armyworm damage to corn planted 
after rye and other grasses where a no-tillage system of planting was used. The 
armyworm moths laid their eggs in the grass. The newly hatched worms are now feed- 
ing on the corn. For control, use 1-1/2 pounds of toxaphene, or 1-1/2 pounds of car- 
baryl (Sevin) , or 1 pound of trichlorfon (Dylox) --applied as a spray over the row 
when damage is present. 

HOMEOWNER INSECTS 

Bean leaf beetles . These are beginning to chew holes in the leaves of green beans. 
This is a dull-red or brown beetle with black spots. It can be controlled with 
carbaryl (Sevin) , applied as a 5-percent dust or a spray prepared by mixing 2 
tablespoons of 50-percent wettable powder in each gallon of water. 

Striped cucumber beetles . Adults are present where young plants of vine crops 
such as cucumber and squash have emerged. These black and yellow beetles mi- 
grate to newly emerging plants and chew on the leaves. They often carry a dis- 
ease called bacterial wilt in their mouths. This wilt kills the plants on which 



the beetles feed. Again, carbaryl (Sevin) applied as a dust or spray will pro- 
vide control. 

SMALL GRAINS 

Armyworms . Don't push the panic button yet on armyworms. Although an occasional, 
small grain field was observed in the south-central section this week with suffi- 
cient armyworms to cause problems, most fields didn't have enough to warrant con- 
cern. Many worms are still small and will continue to feed for several days. The 
cool weather has slowed down their feeding and development. 

Continue to check small grain fields carefully for another two weeks. Cool, wet 
weather is favorable for armyworm development. High temperatures help produce 
a disease that may kill many of the worms. 

To determine the need for treatment in a grain field, look first in the thick, 
lodged spots. Then strike the plants vigorously to dislodge the worms and count 
those on the ground or in the debris between the rows , or in the cracks and crev- 
ices in the soil. If you find many worms, make counts in several places in the 
field and figure the average number per linear foot of row. If the average is 
six or more worms per linear foot of row throughout the field, chemical control 
is justified. If you do not find worms or only a few in the thick or lodged 
spots, treatment is not necessary. 

Leaf-feeding is not serious when worm populations are low, but an average popula- 
tion of less than 6 worms per linear foot of drill row can still cause damage if 
the worms are cutting off the heads of wheat. Also, if most worms are about 1-1/4 
to 1-1/2 inches long and are fat, they are through feeding. Do not use insecti- 
cides then. It is too late. 

Applications of 1 to 1-1/4 pounds of malathion, 1 pound of trichlorfon (Dylox) , 
or 1-1/2 pounds toxaphene per acre will control armyworms. Do not feed forage or 
straw treated with toxaphene to dairy cattle, livestock being fattened for slaugh- 
ter, or poultry. After using trichlorfon, do not forage or feed the wheat within 
three days. There is no waiting period between the application of toxaphene and 
grain harvest; a week is required when applying malathion, 21 days for trichlorfon. 

Where the worms are migrating into corn, spray the infested rows as well as a 25- 
to 30 -foot strip of wheat or grass adjacent to the corn. 

FORAGE INSECTS 

Alfalfa weevils . The larvae are pupating in the southern section, and populations 
are leveling off or declining. If damage is present, the best approach now is to 
cut and remove the hay and watch the new growth of the second crop for damage. If 
it does not green-up within 2 to 4 days after cutting and if worms are noticeable, 
spray the alfalfa promptly. Alfalfa weevil larvae will be present for several 
weeks in southern sections, but the peak period for damage is over in this area. 

In the central and northern sections, larval populations are still low and non- 
economic. See Report No. 7 for insecticide suggestions. 



WEEDS 



WEED CONTROL IN GRAIN SORGHUM 



The southern corn leaf blight caused farmers to take a closer look at grain sor- 
ghum this year as an alternate crop. Several herbicides are cleared for grain 
sorghum, but few for forage sorghum. 



The corn herbicides suited for sorghum are Ramrod, Ramrod/atrazine, AAtrex, and 
2,4-D. Milogard, Herban, Herban 21A, and Herban 21P are specific sor- 
ghum herbicides. 

Ramrod (propachlor) is cleared for preemergence use on grain sorghum (milo) but 
not on forage sorghum. The rate is the same as for corn. Ramrod can also be 
mixed with AAtrex or Milogard or followed with a postemergence spray of 2,4-D 
or AAtrex to control broadleaf weeds. 

AAtrex (atrazine) is cleared for use in Illinois only as a postemergence appli- 
cation. AAtrex is cleared for preemergence application, using combinations of 
Ramrod and Herban. 

Milogard (propazine) is a preplant or preemergence herbicide used on grain or 
wheat sorghum. It is chemically related to atrazine, but is less effective on 
some grassy weeds. The rate of Milogard 80W is 2-1/2 to 4 pounds per acre 
(broadcast basis), depending on the soil. Milogard cannot be used on sandy 
soil. Corn and sorghum are the only crops that can be grown on fields treated 
with Milogard for eighteen months after application. 

Herban (norea) is a substitute urea herbicide, sold as a 80-percent wettable 
powder. It is usually combined with atrazine or propazine. Herban 21A and 
Herban 21P are mixes of 2:1 Herban (norea) with atrazine and propazine, respec- 
tively. 

2,4-D can be used to control many broadleaf weeds as a postemergence treatment. 
Sorghum is most tolerant to 2,4-D when it is 4 to 12 inches tall. Use extension 
nozzles (drops) if the sorghum is over 8 inches tall. 

2,4-D and AAtrex (atrazine) are the only herbicides presently cleared for use on 
forage sorghums and sorghum- sudan hybrids. Narrowing the row widths and using 
high plant populations are also good practices for weed control in forage sorghums. 

CORN INJURY PROBLEMS 

We have received several reports of corn injury, particularly "leafing-out" under 
the ground. This problem can be caused by several things, including some chemi- 
cals. However, other causes would include crusting of the ground, planting too 
deep, or damage to the seed germ. In several cases, small round seed was planted. 
Such seed is much more susceptible to germ damage than flat seed because of the 
germ's convex surface. Some inbred corns are more susceptible to "leafing-out" 
under the surface than others because of a short first internode. So you would 
expect some single-cross corns to be more susceptible than others. 

In some cases, the herbicide Lasso was used. Lasso injury can cause "leafing- 
out" under the ground because of a constriction of the coleoptile. Lasso injury 
usually causes onion- leaf ing on a few of the emerged plants. 

WEED PROBLEMS 

We have also received several calls about wirestem muhly control in corn- -especially 
from the northwestern part of the state. There is no good herbicide- control program 



-5- 

£or this weed. A delayed- tillage practice involving late planting has provided 
the best control. But such a practice fits soybeans better than it does corn. 
AAtrex (atrazine) , applied either preemergence or posteraergence, has given some 
temporary control. 

We have also received several samples of Jerusalem artichoke. This is a peren- 
nial sunflower from the northwestern part of the state. This weed is fairly 
susceptible to 2,4-D or Banvel. 



PLANT DISEASES 



PROGRESS REPORT ON SOUTHERN CORN LEAF BLIGHT 

Southern corn leaf blight (SCLB) was identified this past week on volunteer corn 
growing in Champaign, Coles, and Marion Counties. All infections are probably 
race T, but this is being checked by inoculating greenhouse plants. The recent 
rains may have spread Eetminthosporium maydis spores from clumps of volunteer 
corn to nearby seedling corn. Small, round- to-oval leaf lesions, with reddish- 
purple or reddish-brown borders, will appear about mid-week if infection has 
occurred . 

These infections are not expected to spread to any great extent. Certainly, no 
epidemic can or will occur until tassel time, or later. At that time, night tem- 
peratures are in the 70' s, dews are heavy, and the canopy of corn leaves slows 
down air movement. All of these conditions favor rapid infection, multiplication 
of the fungus, and the spread of the disease. Infected volunteer corn- -if you 
search for it- -can probably be found now in fifty or more Illinois counties. 

We do not expect SCLB to be as serious this year as in 1970 because a much higher 
percentage of the fields are planted with resistant N corn, highly tolerant blends, 
and T-cytoplasm corn that yielded well in 1970 where the blight was severe. In 
addition, relatively few H. maydis spores will be blown up from the Gulf States, 
because most of their production is in N or ¥2 corn. We continue to pick up a 
few of the H. maydis spores each week at both Dixon Springs and Urbana. 

The states now reporting SCLB in fields or in volunteer corn include Florida, 
Mississippi, and Texas. The infected areas are small, and the blight is not 
spreading anywhere in the South as rapidly as it did in 1970. Because of the 
recent widespread rains, all states where SCLB was severe in 1970 will probably 
report infections within the next week or two. 

BACTERIAL BLIGHT OF OATS 

The Plant Disease Clinic has recently received several oat specimens with bacter- 
ial blights. The symptoms appear as either gray-brown centered lesions with a 
broad, light-green area fading to a straw-colored halo (Halo Blight) or water- 
soaked streaks and blotches that turn brown and extend for the length of the 
leaf without a halo (Bacterial Stripe Blight) . The infected leaves die-back from 
the tips, giving the infected areas and even complete fields a brownish cast. No 
loss in yield or grain quality is expected. The affected oat fields should appear 
normal in another week or so. 

Both of these bacterial blights are favored by cool, rainy weather and are checked 
by warm, dry periods. The causal bacteria overwinter in infected seed, plant ref- 
use, or soil, and are transmitted by rain and wind and insects. Because of recent 
legal action, seed treatments containing mercury cannot be recommended. Consequently, 



you must rely on resistant varieties for control. More details are given in Re- 
port on Plant Diseases No. 106, "Bacterial Blights of Oats," available from the 
Department of Plant Pathology, 218 Mumford Hall, Urbana, Illinois 61801. 

SOYBEAN SEEDLING DISEASES 

Recent rains and the cool, cloudy weather have kept many fields on the wet side. 
As a result, we have received many soybean specimens at the Plant Disease Clinic 
that show signs of Rhizoctonia, Pythium, and Phytophthora root rots. 

Rhizoctonia infection produces sunken, reddish-brown lesions on the main root 
and stem below the soil line. Circular patches of dead plants, 4 to 10 feet in 
diameter, may appear anytime from now until mid- July. 

Pythium- infected plants have soft, dark rotted areas that may extend up the stem. 
These areas become translucent and water-soaked. They often tear away when the 
plant is pulled from the soil. Infected plants usually appear singly or in small 
groups, and will probably cause little yield reduction. 

Phytophthora root rot is characterized by dark-brown lesions on the root and stem. 
These lesions extend as much as 6 inches above the soil line, as opposed to the 
reddish-brown decay caused by Rhizoctonia. Yellow plants killed by Phytophthora 
occur in sections or rows in the low areas of a field. 

Planting healthy, high-quality seed in warm, well-drained soil is the only con- 
trol measure available for Rhizoctonia and Pythium. All varieties are uniformly 
susceptible. There are many varieties highly resistant or immune to Phytophthora 
rot. These should be planted in poorly drained soils where there is a history 
of Phytophthora. Report on Plant Diseases No. 504, "Root and Stem Diseases of 
Soybeans," contains more details. It is also available from the Department of 
Plant Pathology. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 

This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Rand e 11 , Don Kuhlman, and Tim Cooley , 
College of Agriculture , University of Illinois at Urbana-Champaign , and the Illi- 
nois Natural History Survey. 

WEEDS: Ellery Knake and Marshal McG lamer y , Department of Agronomy. 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 

AG COMMUNICATIONS: Ray Woodis. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



- At- / 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT, WEED & PLANT DISEASE SURVEY BULLETIN 



ATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 10, June 4, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and oommercial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



INSECTS 



CORN INSECTS 

Wireworms . This week the number of complaints increased. They involved a variety 
of rotations , but were most common about corn in fields that were in wheat in 1969. 

This pest lives as a larva in the soil for two to six years. A wireworm problem 
this year usually means there will also be one in the same spot next year, so 
plan accordingly. 

Wireworm damage usually declines by mid- June because the worms go deeper into the 
ground when the soil becomes warmer and drier. 

In cases ivhere replanting in necessary, use one of the organic phosphate 
insecticides --Thimet, Dyfonate, and Dasanit at 1 pound or diazinon at 2 pounds 
per acre. These will control small wireworms, but may not control the large ones. 
A rain after application is helpful. We have had several reports of wireworm- 
control failure with row treatments of aldrin, heptachlor, and chlordane. 

It may also be possible to straddle the rows and replant leaving the old stand. 
Later, you can cultivate- out the poorer stand. Do not use an insecticide if 
replanting to beans. The only insecticide with label approval for soybean soil 
treatment is diazinon. 

Cutworms . A few new infestations were reported this week. Later ones are still 
possible, but this depends on the weather. Cool, wet weather would encourage the 
development of the second generation, particularly in northern Illinois. 

European corn borers . It is still impossible to determine the exact situation. 
The most advanced fields in western Illinois should be observed carefully in 
about two to three weeks. The survival of borers in these fields will be high, 
and the moths will tend to concentrate their egg-laying in such fields. The 
large amount of early planted corn will provide the moths with lots of places 
to deposit eggs. The first generation population, therefore, should be scattered 
over a large area while the second generation may be concentrated in the smaller 
acreages of late-planted fields. 



-2- 

Common stalk borers . These striped worms with a dark-purple band around the mid- 
dle attack corn alongside fence rows, grass waterways, and ditch banks where they 
have overwintered as eggs . When the worms outgrow the grass or weed stems or the 
grass is mowed, the borers migrate into the adjacent corn. Sometimes, an attack 
on young plants by the borers will kill the plant; other times, the plant may live 
but will fail to produce an ear. Since these borers chew in the center of the 
plant, the leaves that emerge are extremely ragged. 

Ordinarily, this pest is serious only along marginal areas such as fence rows, 
waterways, and the like. But common stalk borers assume a new proportion as a 
corn pest in no -till corn being grown in grass sod. These borers are very num- 
erous throughout such fields. As the grass dies after being sprayed with a weed 
killer, they concentrate on the corn. We have seen severe damage by this pest 
for three years now. This year will probably be no exception. 

Control is on a catch-as-catch-can basis. A spray of carbaryl (Sevin) at 1 to 2 
pounds per acre directed at the base of the plant may be helpful. As the borer 
leaves one plant and crawls to another, it will contact the chemical. 

These pests are now appearing, so watch for wilting plants and check for this 
insect. 

SMALL GRAINS 

Armyworms . This pest is still present in wheat, and a few severe infestations 
have been reported this week. Examine fields snowing luxuriant growth. 

To determine the need for treatment, look first in the thick, lodged spots. Then 
strike the plants vigorously to dislodge the worms. Count those on the ground 
or in the debris between the rows, or in the cracks and crevices in the soil. If 
you find many worms , make counts in several places in the field and figure the 
average number per linear foot of row. If the average is six or more worms per 
linear foot of row throughout the field, chemical control is justified. If you 
do not find worms or only a f ew in the thick or lodged spots , treatment is not 
necessary. 

After wheat is in the dough stage, loss of leaves is relatively unimportant. The 
real damage from armyworms will occur if they begin to cut the wheat heads or 
migrate to other, nearby crops. 

When using toxaphene, do not expect good control for about four days. Not only 
is toxaphene a slow-acting toxicant, but 50 percent of the worms will not come 
in contact with the spray for at least 48 hours. 

Of encouragement is the fact that wasp parasites of armyworms are beginning to 
appear in numbers and may control many infestations. The clusters of small 
white cocoons found in the ground in wheat fields are the pupal stage of this 
parasite. The wasps will emerge from them and lay eggs in more armyworms. In 
one field, about 25 percent of the armyworms had been parasitized this week. 

SOYBEANS 

Clover root curculios . This grey snout beetle often migrates from alfalfa and 
clover fields when they are plowed. Tliese beetles concentrate on soybeans, 
eating notches in the new leaves and gouging holes in the stems. Often, the 
leaves are almost entirely consumed. A spray of malathion or carbaryl will 
control this pest, if control is needed. 



LIVESTOCK INSECTS 

Pasture flies are increasing, particularly in the central and southern sections 
of Illinois. Horn flies , stable flies , and face flies rob you of milk or beef 
production. Don't let flies pick your pocket. Follow these suggestions. 

For control on dairy cattle, apply crotoxyphos (Ciodrin) as a 2-percent, water- 
base spray at the rate of 1 to 2 ounces per animal two to four times per week. 
A 1-percent dichlorvos (DDVP) or a 0.1-percent pyrethrum spray, applied at 1 to 
2 ounces per animal each day, can also be used. Pay particular attention to 
the animal's legs and undersides when spraying. Also, for dry stock and young 
stock on pasture, as well as for lactating animals, use a 1-percent Ciodrin, 
water-diluted spray. Apple 1 to 2 pints per animal, as often as once per week 
if needed. Ciodrin is the most effective insecticide for face-fly control . 
All of the above insecticides provide good control of horn flies and fair con- 
trol of stable flies. 

To control pasture flies on beef cattle, apply a water-base spray of 0.5 percent 
toxaphene, using 1 to 2 quarts per animal every three weeks. Toxaphene provides 
excellent control of horn flies, fair control of stable flies, and poor control 
of face flies. 

If face flies become a serious problem, use crotoxyphos (Ciodrin) as suggested 
for young dairy cattle. A canvas or burlap head-oiler or back-oiler, saturated 
with a solution 5-percent toxaphene in oil, will provide some relief against 
face flies. Do not apply toxaphene to beef cattle within 28 days of slaughter. 

HOMEOWNER PROBLEMS 

Mosquitoes . To help reduce the number of mosquitoes in home yards, follow these 
steps : (T) Eliminate standing water in such places as eave troughs, old tires, 
tin cans, childrens' toys, storm sewers, etc. (2) Apply a water-base spray con- 
taining 1-percent malathion (2 ounces of 50- to 57-percent liquid concentrate 
per gallon of water) to shrubbery and tall grass. Repeat the treatment every 
week or two if needed. (5) Keep the screens on doors and windows in good re- 
pair. (4) Hang plastic resin strips (2 by 10 inches) containing 20 -percent 
dichlorvos (DDVP) --one strip per 1,000 cubic feet of space, or about one per 
room. These strips will kill mosquitoes and flies afor 4 to 6 weeks. Do not 
use these strips in kitchens or other areas where food is handled. Do not use 
them in any room where infants, the ill, or aged persons are confined. A 0.1- 
percent pyrethrum space spray- -applied from a pressurized spray can- -can be 
used for quick knockdown in place of the dichlorvos resin strips. Frequent 
treatments will be needed during problem periods. (5) When entering mosquito- 
infested areas, use a repellent. One of the most-effective mosquito repellents 
is DEET (diethyltoluamide) . (6) For quick knockdown at cookouts, outdoor par- 
ties, or picnics, use either 0.1-percent pyrethrum or 0.5-percent dichlorvos 
(DDVP) solution as an oil- or water-base, space spray. Spray the mist lightly 
beneath tables and chairs and into the air for a few feet around the area. Re- 
peat the treatment as needed. 



WEEDS 
2,4,5-T USAGE 



We've had several questions about using 2,4,5-T. Last year use of 2,4,5-T was 
suspended or canceled around homes , on food crops , and on lakes , ponds , and 



-4- 

ditch banks. After recent hearings, the Environmental Protection Agency (EPA) 
announced that it "found no imminent hazard requiring suspension of the regis- 
tered uses of 2,4,5-T." They also issued this statement: 

"2,4,5-T is a very effective herbicide which is widely used for controlling brush 
on rangelands and undesirable broadleaf trees in forestry programs. This chemi- 
cal should be used in such fashion that no residues will result in food or feed. 
Milk cows should not be grazed on treated areas for a few weeks after treatment, 
and meat animals should not be permitted to graze freshly treated areas for a 
few days prior to slaughter." 

So, 2,4,5-T can now be used for brush control, as long as the above restrictions 
are followed. "Brushkiller" (a mixture of 2,4-D and 2,4,5-T) is also subject to 
the same restrictions. Silvex or dichlorprop are two brush herbicides that can 
still be used around ditches and waterways where it is necessary to use something 
besides 2,4-D. Silvex is sometimes sold under the tradenames of Kuron and Silvi- 
Rhap. Dichlorprop is soil as Propi-Rhap. 

POSTEMERGENCE AATREX 

Some advisers are concerned about potential injury after they apply atrazine 
(AAtrex) and oil for grass control in corn. Corn injury can occur with the 
atrazine-oil combination. This is most likely to happen on corn exposed to 
stress, such as cold temperatures or frost. 

For maximum weed control on grasses, the grass weeds should be less than 1-1/2 
inches tall. The rate for atrazine (AAtrex) is 2-1/2 pounds per acre of the 
SOW material. The oil is usually added at the rate of 1 to 2 gallons per acre. 

Agricultural surfactants are sometimes used rather than oil. Surfactants are 
usually used at the rate of 1 to 2 quarts per 100 gallons of spray, so you 
have a smaller volume of material to handle. The performance of oils and sur- 
factants is about equal. Any difference is usually in favor of the oils. 

Surfactant and oil combinations are presently available. They combine the 
effectiveness of the oil with the lower volume of the surfactant. These are 
usually used at the rate of 1 to 2 quarts per acre. 

Remember, when mixing atrazine (AAtrex) and oil, be sure to mix the atrazine 
with the water first and then add the oil. This prevents "gunking" and disper- 
sion problems. 



PLANT DISEASES 



PROGRESS REPORT ON SOUTHERN CORN LEAF BLIGHT 

As of June 3, southern corn leaf blight has been found in the following counties: 
Jackson, Clay, Effingham, Edgar, Coles, Gallatin, Douglas, Jasper, Monroe, and 
Union. In Jackson County, it was found on the agronomy farm at Carbondale; in 
Clay County, on corn planted this spring in a farmer's field. In all other 
cases, blight has been identified only on volunteer corn. So far, there is no 
indication of any spread to nearby planted corn. There is no cause for alarm. 
Cur predictions for 1971 are the same as last week (see Bulletin No. 9). 



-5- 

The new states reporting SCLB since May 28 include: Nebraska (1 county), Iowa (5), 
Alabama (2), Florida (5), Kentucky (1), and Tennessee (1). In all cases, the re- 
ports involve volunteer corn. Only Florida reports a spread of the disease into 
planted fields of corn as well as "spore showers." The number of H. maydis spores 
caught in our spore traps remains extremely low- -about 1 spore every three days. 

OATS 

In general, the Illinois oat crop looks fine. As before, small pockets of yellow 
dwarf or red leaf can be found, usually near field borders. The diseased plants 
are stunted and are heading poorly. Some blasting is apparent. Affected plants 
have a dull yellowish-red appearance. Details are given in Report on Plant Dis- 
eases No. 101, available from the UI Department of Plant Pathology, 218 Mumford 
Hall, Urbana, Illinois 61801. 

Oat smuts --both loose and covered- -can also be found in small amounts. The plants 
are stunted. The kernels are replaced by black masses of smut spores that quickly 
blow away leaving denuded panicles. We expect more smut to develop in future years 
because there is no good, inexpensive substitute for mercury seed treatments. 

WHEAT 

The Illinois wheat crop looks excellent. At present about the only disease of any 
consequence is Septoria leaf blotch. Look for light- to reddish-brown irregular 
lesions on the leaves. They are surrounded by a yellowish band. Black specks 
appear in the light-brown to ash-white centers as the lesions age. Little reduc- 
tion in yield is expected. Control measures are listed in Report on Plant Dis- 
eases No. 105, also available from the Department of Plant Pathology, Urbana. 



SPECIAL NOTE TO COUNTY EXTENSION ADVISERS 

Personnel from the USDA and the Illinois Department of Agriculture are checking 
near infested areas for cereal leaf beetles. Additional counties have recently 
been added to the list of those with infestations. When this happens it does 
not mean that economic damage has occurred, only that at least one beetle has 
been found. Economic damage in newly infested areas is not expected for a few 
more years. 



DATES FOR DIGGING IN WIREWORM PLOTS 



Tuesday, June 8, Livingston County - -9: 00 a.m. Contact Paul Wilson, Extension 
Adviser, for the location near Long Point. Phone: 815/844-3622. 

Wednesday, June 9, Ogle County - -1:00 p.m. Contact Stan Eden, Extension Adviser, 
for the location. Phone : 815/732-2191. 

Thursday, June 10, Perry County --!: 00 p.m. Contact Charles Howell for directions. 
Phone: 618/357-5671. 

Friday, June 11, Kane County --9:00 a.m. First set of buildings north of the junc- 
tion of Route 31 and the Red Gate Road, west side of Rt. 51. Contact Phil Farris, 
Extension Adviser. Phone: 312/584-6166. 



READ THE LABEL AND FOLLOW ALL PRECAUTIONS 



This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Rand el 1 , Don Kuhlman, and Tim Cooley , 
College of Agriculture , University of Illinois at U rbana- Champa ig n , and the Illi- 
nois Natural History Survey. 

WEEDS: Ellery Knake and Marshal McG lamer y , Department of Agronomy. 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 

AG COMMUNICATIONS : Ray Woodis. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



TrAU 1 




COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA-CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA, ILLINOIS 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



fATE/COUNTY/LOCAL GROUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



-77V. 



FOR IMMEDIATE RELEASE 



ML .? 1371 " 

No. 11, June 11, 1971 



This series of weekly bulletins provides a general look at the insect, weed, and 
plant disease situation (fruit and oommeraial vegetables excepted) , along with 
suggested, abbreviated control measures. Each individual should check his own 
fields to determine local conditions. 



INSECTS 



CORN INSECTS 

Wireworms . This pest continued to damage corn this week, but the problem seems 
to be lessening. Wireworm damage usually declines by mid- June because the worms 
go deeper into the ground when the soil becomes warmer and drier. 

In cases where replanting is necessary, use one of the organic phosphate 
insecticides --Thimet, Dyfonate, or Dasanit at 1 pound or diazinon at 2 pounds per 
acre of actual chemical. These will control small wireworms, but may not control 
the large ones. A rain after application is helpful. 

Black cutworms . A few scattered reports of damaged corn were received this week. 
Continue to be on the lookout for damage. Control suggestions were given in Re- 
port No. 9. 

European corn borers . This situation will need to be watched for the next three 
weeks . In general, the development of these borers appears to be slower than nor- 
mal this year, which would allow for greater survival. 



In the southern section of Illinois, egg-laying reached its peak this week. The 
tiny borers now present in the whorls of corn under 40 to 45 inches in height 
(from the ground to the tip of tallest leaf) will die 
is 50 inches or taller, check for borer infestations, 
make the application this week. 



In fields where the corn 
If treatment is justified, 



In the central section, moth- emergence is well along and egg- laying has 
started. The earliest time for treatments, if needed, would be in about ten 
days (June 21 or after). In the northern section, the moths are just beginning 
to emerge. 

To determine the need for treatment, first check the tassel ratio. Dig up a 
plant and measure from the bottom of the plant to the tip of the longest leaf. 
Split the plant and find the developing tassel. Measure from the bottom of the 
plant to the tip of the tassel. Divide the tassel height by the plant height 
and multiply by 100. If the tassel ratio is 30 or over and if 75 percent or 
more of the plants have corn-borer feeding on the whorl leaves , the field should 



-2- 

be treated- -but not until the tassel ratio is at least 35, preferably 40 to 50. 
The percentage of infested plants required to justify treatment can be reduced 
with higher tassel ratios. 

Use 1 pound of actual diazinon in granular form per acre, or 1-1/2 pounds of car- 
baryl (Sevin) as granules. For spraying, use the same amount of actual insecticide 
per acre, and direct the spray to the upper third of the plant. Aerial applications 
should be as granules , not sprays or dusts . Allow 10 days between treatment and the 
ensiling of corn when applying diazinon; carbaryl has no waiting period. Commercial 
applicators may prefer to use parathion at 1/2 pound actual per acre, which will pro- 
vide good control of the corn borer. Parathion has a 12-day waiting period between 
treatment and harvest. 

Garden symphylans or garden centipedes . Damage has been found in two fields of 
corn in the central section. These insect relatives are small (1/16 to 5/16 of 
an inch), white, and have many legs. They move rapidly in the soil, attacking the 
roots. They prefer the root hairs and tender new roots, but they will reduce the 
root system to a stub if the infestation is severe. Infested plants are stunted 
and may be killed. These pests feed throughout the season, moving closer to the 
surface when conditions are moist and going deeper when they are dry. 

To check for centipedes, look in areas where the stand is irregular. Locate plants 
that appear stunted. Dig up the plant with a spade full of soil, and place this on 
a sheet of plastic or cloth. Examine the root system for feeding injury. Carefully 
sort through the soil, breaking up the clods and watching for the white, moving 
centipedes. It usually takes a hundred or more garden centipedes per hill to cause 
noticeable injury. Do not become alarmed if you find 5 to 10 in each hill. This 
number is common in many cornfields. 

If the plants are being seriously affected, we suggest an application of granular 
Dyfonate on a trial basis. Band 1 pound of actual Dyfonate per acre at the base 
of the plants, and cover the granules by cultivation. Rain following the treat- 
ment will enhance the possibility for success. If corn is to be replanted this 
year or planted in this same field next year, apply 1 pound of actual Dyfonate 
per acre as granules in a 7 -inch wide band just ahead of the press wheel. 

Corn rootworms . Egg-hatch has started, and will continue for several weeks. It 
is too soon to predict the severity of the problem. Damage is likely to be the 
worst north of a line from Carthage to Bloomington to Joliet. 

If you suspect a rootworm problem in your fields and did not use an organic phos- 
phate or carbamate insecticide at planting time, apply one within the next two 
weeks. Use granules applied at the base of the plants. Cover with cultivation. 
The insecticides suggested for basal treatments are BUX, Dasanit, Dyfonate, or 
phorate (Thimet) . Use the rate of 1 pound of actual chemical per acre. 

Corn leaf aphids . These were found in corn whorls in the south- central and south - 
ern sections of Illinois this week. The aphids are just getting started, and it 
is too soon to make predictions. 

White grubs . A few reports of damage to corn and soybeans have been received from 
the central section. These grubs vary in size, but are mostly small. They will 
continue to feed throughout the growing season. Attempts to control white grubs 
with basal applications off the cultivator have failed. If soybeans are to be 



replanted, try 2 pounds of actual diazinon per acre in a 7- inch band just ahead 
of the press wheel. 

SPECIAL NOTE TO SWEET CORN PRODUCERS IN SOUTHERN ILLINOIS ESPECIALLY THE SOUTH- 
WESTERN -AREA 

Corn earworm moths are flying and egg- laying is underway. The eggs are being 
deposited on silks if present or in whorls. .An average of one egg per silk was 
found in fields this week. Hatch occurs in about two to three days; therefore, 
treatments should be made on silking corn at least every 48 hours where whorl 
feeding is present. One of the sprayer nozzles should be directed down in the 
whorl . 

For control, use either 2 pounds of actual carbaryl (Sevin) or 1-1/2 pounds of 
actual Gardona per acre. 

SOYBEANS 

Bean leaf beetles . These are eating holes in the leaves of soybeans. No seriously 
aamagea rields have been observed or reported. Sprays of carbaryl (Sevin) or toxa- 
phene are effective. 

FORAGE INSECTS 

Alfalfa weevils . They continue to present some problems. In the southern and south - 
central sections, the new growth of the second crop is being damaged in some fields. 
This is being caused by a combination of feeding by the larvae and the new spring 
adults. Malathion is effective against the larvae, but is not highly effective 
against the adults. Therefore, use one of the other insecticides suggested in Re- 
port No. 7. In the central and northern sections a few fields are being damaged. 
It would be best to cut and remove the crop, then watch the new growth for signs 
of damage. If the new growth does not green-up in two to four days and worms are 
present, apply an insecticide promptly. 

GENERAL 

Grasshoppers . They are hatching-out in fence rows, ditch banks, roadsides, and 
hay fieias. Grasshoppers were more numerous last fall than for several years, es- 
pecially in the central and southern sections. Hot, dry weather during the next 
two to three weeks (their peak hatching period) will favor the survival of the 
"hoppers." If lots of tiny "hoppers" appear in grassy areas, apply a spray of 
5/4 pound of carbaryl or 1-1/2 pounds of toxaphene per acre. Use carbaryl on hay 
fields. This will prevent migrations of these same grasshoppers into more valuable 
crops like corn and soybeans later on. 

INSECTS IN STORED GRAIN 

Wheat harvest is just around the corner and such insects could present a greater- 
than-normal problem this year, especially the Indian meal moth. Dr. Ralph 
Sechriest of the Illinois Natural History Survey has confirmed resistance of the 
Indian meal moth to malathion here in Illinois. Reports of malathion failures 
in attempts to control this insect have been on the increase since 1969. More 
are expected this year. 



-4- 

Those of you selling or making suggestions for the use of malathion on stored 
wheat can expect complaints from farmers , beginning in late July through Septem- 
ber. At present, we have no substitute for malathion as a protective material 
for stored grains. Also, there does not appear to be a total failure of mala- 
thion as yet to control the Indian meal moth. Malathion is still effective 
against the remainder of the insect complex that attacks stored wheat (about 
twelve important ones). We feel the continued use of malathion in a complete 
control program involving (1) bin cleanup, (2) bin spraying, (5) treatment of 
grain during storage, and (4) two surface treatments --one at the conclusion 
of storage and one in early to mid-August- -will still provide satisfactory 
protection on the vast majority of farms. 

Fumigation with Phostoxin, the 75 mixture (ethylene dibromide plus methyl bro- 
mide) , the 75-25 mixture (ethylene dichloride plus carbon tetrachloride), or the 
80-20 mixture (carbon bisulfide plus carbon tetrachloride) can be used for emer- 
gency purposes when insects are present, but such treatments will not provide 
lasting protection. 

HOMEOWNER INSECTS 

Bagworms . The hatch is complete in the southern section. Sprays should be ap- 
plied immediately. The target date for spraying in the central section is after 
June 15, in the northern section, after June 50. 

Control bagworms while they are small and easy to kill. Once the bagworms be- 
come half grown or more, sprays often fail. 

For control, use carbaryl (Sevin) , diazinon, or malathion. Follow the direc- 
tions on the label. Check carefully for plants that could be injured by the 
insecticide used. One application applied at the correct time is usually all 
that is needed. 

Sod webworm moths . They are flying now. These light, buff -colored moths fly in 
a zig-zag pattern over lawns just about dusk. They are laying eggs that will 
produce the first generation of worms. This generation is seldom numerous enough 
to cause damage. The second- generation buildup of worms, coming in late July 
through early September is the one that often presents problems. Brown spots in 
the lawn and the sudden appearance of numerous birds like robins are signs that 
webworms may be at work. 

If the webworms strike, you can control them with carbaryl (Sevin), diazinon, or 
trichlorfon (Dylox) . These can be used as sprays or granules. 

Aphids . These are common on many trees and shrubs- -tulips, willows, sycamores, 
honeysuckles, roses, and others. These small, soft-bodied insects (green, yel- 
low, black, or red) suck the sap from plants and secrete a sticky material called 
"honeydew." This sugary material coats the leaves, making them glisten. A black 
mold may develop when the honeydew deposits are heavy. Cars parked beneath in- 
fested trees become covered with sticky spots. 

Ants feed on the sugary secretions of aphids. Thus, the presence of a large num- 
ber of ants on a plant may be a sign that aphids are also numerous. Another sign 
of infestation is the presence of white specks on leaves. These are the cast skins 
of the aphids. In most cases aphids or plant lice do little damage. However, if 



leaves begin to curl and dry, apply a spray using 2 teaspoons of a 50- to 57- 
percent malathion or a 25-percent diazinon liquid concentrate per gallon of wa- 
ter. Do not use malathion on African violets or canaert red cedar. Do not use 
diazinon on ferns or hibiscus plants. 



PLANT DISEASES 
SOUTHERN CORN LEAF BLIGHT 

Confirmed cases of the blight have now been recorded in twenty-nine Illinois coun- 
ties. This development was quite unexpected. If the weather remains warm and dew 
and rainfall proide adequate moisture, changes in the near future could be even 
more dramatic. 

During the past week, probably because of the warm weather and the presence of 
adequate moisture, there were major changes in southern Illinois corn fields. Af- 
ter checking fields in Macon, Effingham, and Shelby Counties, plant pathologists 
reported two significant changes: 

1. The blight is spreading from volunteer corn to fields planted with T cytoplasm 
or blended seed. 

2. The blight is moving from the lower to the upper leaves of the corn plants. 

These changes are most obvious in the southern half of the state, particularly 
in the southern quarter. 

Farmers should check fields of T cytoplasm and blended corn closely. If there 
are blight lesions on the upper leaves, a close and continuing check should be 
made of the conditions in all such fields. Where lesions are evident on the 
upper leaves, the farmer will have to decide whether or not to plow under the 
corn and replant with soybeans or sorghum. 

WHEAT 

Scab or head blight . This can now be found in thousands of Illinois wheat fields, 
as a result of the widespread rains and the warm, humid weather last week. The 
scab is appearing as a bleached, light-straw color on the wheat heads. They should 
still be the normal green in most fields. A salmon-pink color may also be evident 
at the base of the glumes. If the weather stays warm and moist, the spikelets on 
early infected heads will become speckled with the black, spore-producing bodies 
of the scab fungus by harvest time. Scab- infested kernels appear to be somewhat 
shrunken and lightweight, with a flaky- to- scabby appearance. The color ranges 
from light brown to pink or grayish-white, depending on the time of infection and 
the weather conditions. 

The same fungus infects other small grains, corn, and forage grasses. It may pro- 
duce a seedling blight, stalk or ear rot, root rot, crown or foot rot, and stem 
blight. For details, check Report on Plant Diseases No. 103, "Scab of Cereals," 
which is available from the Department of Plant Pathology, 218 Mumford Hall, Ur- 
bana, Illinois 61801. 

Blackening . This is now common on the culms and glumes of certain wheat varieties 
such as Ben Hur. There is no organism or infection involved. Neither the grain 



yield nor the quality will be affected. The reason some wheat varieties tend to 
blacken during certain seasons is unknown. 



WEEDS 

BROADLEAF WEED CONTROL IN CORN 

When is corn most susceptible to 2,4-D injury? The answer is that corn in almost 
any stage of growth can be injured by 2,4-D. However, a few precautions will keep 
damage to a minimum. Most 2,4-D labels carry the warning not to treat corn when 
it is silking and tasseling. Using "drop" nozzles is recommended if the corn is 
more than S to 12 inches tall. 

Spraying 2,4-D during cool, wet weather or hot, humid weather--when the corn is 
under stress- -may increase the possibility of injury. Applying 2,4-D can cause 
brittleness, bending and lodging- -especially in fast-growing corn. As an added 
precaution, it is best to avoid cultivating corn for about a week after applying 
2,4-D. 

The rate of 2,4-D to use varies with the concentration and formulation. The con- 
centration of 4 pounds per gallon of 2,4-D is the most common one; however, other 
concentrations are available. Amine formulations of 2,4-D require higher applica- 
tion rates than ester formulations, but the amine formulations have less of a drift 
hazard. 

Banvel can also be used to control broadleaf weeds in corn. This chemical provides 
effective smartweed control, with fewer corn- injury problems than 2,4-D. However, 
special care must be taken to prevent damage from drift to soybeans , which are 
especially susceptible to such injury. 

AAtrex (atrazine) used as a postemergence spray also provides effective control 
of broadleaf annual weeds in corn. However, grasses must be treated before they 
are 1-1/2 to 2 inches tall. 

Remember that the timely use of a rotary hoe and cultivator is still an effective 
means of weed control. Used correctly and at the right time, these tools can 
greatly improve a poor or fair weed-control situation caused by herbicide failure. 



READ THE LABEL AND FOLLOW .ALL PRECAUTIONS 
This weekly report was prepared as follows: 

INSECTS: H.B. Petty, Steve Moore, Roscoe Randell , Don Kuhlman , and Tim Cooley , 
College of Agriculture , University of Illinois at Urbana-Champaign , and the Illi- 
nois Natural History Survey. 

WEEDS: Ellery Knake and Marshal McG lamer y , Department of Agronomy. 

PLANT DISEASES: M.C. Shurtleff and Ed Burns, Department of Plant Pathology. 

AG COMMUNICATIONS : Ray Wood is. 

The information for this report was gathered by these people, staff members, 
county Extension advisers, and others, in cooperation with the USDA Agricultural 
Research Service, Plant Pest Control Branch. 



i^ / 







1 s 
COLLEGE OF 
AGRICULTURE 
UNIVERSITY OF 
ILLINOIS AT 
URBANA CHAMPAIGN 
AND NATURAL 
HISTORY SURVEY 
URBANA. ILLINOIS 


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til 




NSECT WEED & PLANT DISEASE SURVEY BULLETIN 



rATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



JHE 03RABK 0E IHB ] 

JUL 81971 



FOR IMMEDIATE RELEASE No. 12, June 18, 1971 

IVERSITY OF ILLINOig 

This series of weekly bulletins provides a gener % a r &~ look at the insect, weed, and 
plant disease situation (fruit and oomrneroial vegetables excepted) , along with 
suggested, abbreviated, control measures . Each individual should check his own 
fields to determine local conditions. 



PRECAUTIONS 



We have an unconfirmed report of the death of a child from a pesticide. A highly 
poisonous pesticide, not available for homeowners, somehow was in a soft-drink 
bottle in a refrigerator. A small youngster drank it. This proved to be fatal 
almost immediately. Safe storage of pesticides is a must. Do not store pesti- 
cide in the refrigerator, the medicine cabinet, under the kitchen sink, or any 
other place where small children can get to it. 

Our Illinois agricultural pesticide accident record is a good one, so now is not 
the time to ease back and become careless. Continue to use proper precautions in 
the mixing and handling of pesticides and always remember to store them where small 
children, persons not accountable for their actions, and animals cannot get into 
them. Never store a pesticide in anything but the original, properly marked con- 
tainer. Remember, unmarked insecticide granules have been fed to livestock. This 
proved to be fatal. Look around, is everything properly marked? 



INSECTS 



CORN INSECTS 

Wireworms . Because of hot weather, wireworms are going down into the soil and 
there is little new feeding damage. These wireworms live in the soil from two to 
six years. Be prepared next year to control wireworms in those spots which were 
badly infested this year. 

Armyworms . Adult armyworms are heavy-bodied brown moths that deposit eggs on grasses 
in weedy cornfields. After consuming the grassy weeds, they turn to the corn. If 
they only eat the leaves below the ears, little damage is done, but when they attack 
the silks and leaves above the ear, yields may be reduced. If your cornfield is 
weedy, watch for armyworms during July. 

European corn borer . Egg mass counts made from Carbondale to Oregon on the west 
half of the state this week revealed remarkably low infestations. Approximately 
100 of the most advanced fields were checked, and counts rarely exceeded 10 egg 
masses per 100 plants. With so much tall corn, female moths readily find a place 
to lay eggs. Rarely is egg-laying concentrated in any one field, and it appears 
that few fields will warrant spraying for first-generation corn borer. But check 
exceptionally advanced fields for another week in southern Illinois, for two weeks 
in central Illinois, and for about two to three weeks in northern Illinois. 



-2- 

To determine the need for treatment, first check the tassel ratio. Dig up a 
plant and measure from the bottom of the plant to the tip of the longest leaf. 
Split the plant and find the developing tassel. Measure from the bottom of the 
plant to the tip of the tassel. Divide the tassel height by the plant height 
and multiply by 100. If the tassel ratio is 30 or over and if 75 percent or 
more of the plants have corn-borer feeding on the whorl leaves , the field should 
be treated- -but not until the tassel ratio is at least 35, preferably 40 to 50. 
The percentage of infested plants required to justify treatment can be reduced 
with higher tassel ratios. 

Use 1 pound of actual diazinon in granular form per acre, or 1-1/2 pounds of car- 
baryl (Sevin) as granules. For spraying, use the same amount of actual insecticide i 
per acre, and direct the spray to the upper third of the plant. Aerial applications 
should be as granules, not sprays or dusts. Allow 10 days between treatment and the 
ensiling of corn when applying diazinon; carbaryl has no waiting period. Commercial 
applicators may prefer to use parathion at 1/2 pound actual per acre, which will pro 
vide good control of the corn borer. Parathion has a 12-day waiting period between • 
treatment and harvest. 

It is possible that many fields will have light first- generation infestations, but 
these fields will supply a great number of moths. Second- generation borer numbers 
could be intense in late fields. 

Corn rootworm . Most rootworms found this week were very small, but a few half- 
grown worms were found as far north as Oregon. If you suspect a rootworm problem 
and you used no insecticide as a band at planting, examine roots and soil now. 
Hatch has not yet reached its peak, and even a few worms per plant at this time 
means greater numbers later. 

Apply cultivation treatments now. Apply granules to the base of the plants. Cover 
by cultivation. The insecticides suggested for basal treatments are BUX, Dasanit, 
Dyfonate, or phorate (Thimet) . Use the rate of 1 pound of actual chemical per acre.. 

Corn blotch leaf miner . This maggot tunnels in the leaves of corn, making irregular 
white longitudinal galleries on the leaves. Damage is not important and no control 
is necessary. 

ALFALFA INSECTS 

Spotted alfalfa aphid . These yellow aphids with black spots feed on the lower 
leaves and stems of the alfalfa plant. They inject a toxin into the plant. Small 
dead spots which enlarge rapidly appear in heavily infested fields. Dry weather 
usually accentuates the damage. 

The apids migrate into Illinois from the southwest and were found in Champaign 
County this week. Every year, some are found in Illinois. 

Demeton (Systox) is preferred and can be used once per cutting and no closer than 
21 days before harvest or pasture. Apply at 1/4 pound per acre. It is every ef- 
fective as a systemic. 

Use 1 pound of malathion, 1/2 pound of diazinon, or 1/4 pound of parathion per 
acre as an emergency treatment. Read precautions on labels. Malathion can be 



-3- 

used on the day of harvest, diazinon requires a 7-day interval, and parathion 15 
days. Parathion should be applied only by professional applicators. 

GENERAL 

Grasshoppers . Tiny, newly hatched grasshoppers are present from one end of the 
state to the other. In some areas, timely rains have killed many of them, but in 
many areas, the small grasshoppers have escaped. Two species are present. One 
is in fence rows, ditchbanks, grass waterways, and similar sod areas. These can 
be sprayed with toxaphene, but do not feed the forage. A second species is present 
in clover fields. When you mow, leave uncut swaths. The grasshoppers concentrate 
in the fence rows and the uncut swaths. They can be sprayed and the hay can be 
cut a day later and used for hay. In this case use malathion or carbaryl (Sevin) . 
Do not apply toxaphene near fish-bearing waters. If clover or alfalfa is blos- 
soming, apply malathion late in the day. Do not use carbaryl if the fields are in 
blossom. 

HOMEOWNER INSECTS 

Galls . Some of the more common galls include maple bladder on maple, various galls 
on oak, and pod gall on honey locust. These are warty- appearing growths that de- 
velop on the leaves. They rarely cause any damage to branches of the tree. Chemical 
control is difficult, since the tiny insect forming the gall is inside it. If treat- 
ment is desired, it will be most effective just before the gall is formed; in most 
instances, this is in the spring as the new leaves are emerging from buds. Hence, 
this should be planned for next spring. 

Cottony maple scale . This scale appears as a sticky, cottony mass on tree branches- - 
especially those of maple and honey locust. At present, these are the adult scales 
with eggs inside the cottony area. These adults are sucking plant sap from the twig. 
The eggs will be hatching in early July, and the young will crawl out onto the un- 
derside of leaves. These crawlers appear as tiny yellow specks on the leaves re- 
maining on the leaves, sucking plant juices until September. For control, spray 
in early to mid-July with malathion. Be sure to thoroughly spray the leaves near 
twigs covered with the cottony masses. 

PLANT DISEASE 

WHEAT 

We are now getting samples of wheat with blasted heads covered with various dark 
molds growing on the glumes, in addition to some Septoria leaf blotch, scab, and 
physiological blackening (see last week's report). 

The blasting of flor