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1941 NO. 28

1

NO. 384

JANUARY 1941

Montana Insect Pests

1939 and

1940

TWENTY^ I CHTH REPORT OF THE STATE
ENTOMOLOGIST

BY

HARLOW B. MILLS, STATE ENTOMOLOGIST

MONTANA STATE COLLEGE

AGRICUL^^AE^rs*™ii;fflsaiECi

OCT 3 1 2007

MONTANA STATE LIBRARY

1515 E. 6th AVE.
HELENA, MONTANA 59620

Bozeman, Montana.
January 1, 1941.
To His Excellency,
Governor Sam C. Ford,
Helena, Montana.
My Dear Sir:

I am pleased to present herewith, the 28th report of the State Entomo-
logist of Montana.

The Office of the State Entomologist was established by the Legislative
Assembly of 1903 with the assigned duties of conducting field investigations
Dn injurious insects within the State, and of investigating outbreaks of in-
jurious insects and making recommendations for control.

Since the establishment of this office 37 years ago, agriculture within
the State has increased greatly, and proportionately more time has been
spent by the State Entomologist in carrying out the duties of the office.
During the last decade of extensive outbreaks of grasshoppers and Mormon
crickets, the major part of his time has been spent in control work.

The law prescribes) that the office carry no salary other than that re-
ceived from the College of Agriculture and Mechanic Arts and the Experi-
ment Station, and twenty years ago this was a reasonable arrangement.
At the present time, however, an equitable distribution of salary should
include an item for this purpose in the annual appropriation for this office.

Grasshoppers, during the past biennium, have been again the major
injurious insects within the State, and have received much attention. It
is estimated that out of a possible loss of $37,365,612 to crops because of in-
festations of 'hoppers and Mormon crickets, a savings of $22,909,265 has
been realized because of cooperative control campaigns with the United States
Department of Agriculture in the last four years.

It should be pointed out that campaigns against such injurious insects have
been made possible only through the assistance of Federal funds. Grass-
hopper bait materials have been purchased for use in the State, and dur-
ing the past two years equipment has been purchased and crews hired for
baiting on abandoned land. While the figures on total Federal expenditures
for grasshopper control during the past two years are not available, of the
$163,046.10 spent on Mormon cricket control in 1939 and 1940, $125,042.96
came from Federal funds. Practically all of the remainder came from county
and individual sources.

Funds made available by the State were far too small even to care for
supervision.

A few newly introduced pests are recorded herein, and mention is
made of one which is within striking distance of us in the West.

Respectfully submitted,

HARLOW B. MILLS,

State Entomologist.

Montana State Library

illllllllllll
3 0864 1004 0573 0

MONTANA INSECT PESTS 1939 AND 1940
Twenty-Eighth Report of the State Entomologist

Harlow B. Mills

INTRODUCTION

The years 1939 and 1940 were characterized, as have been all
in the decade just past, by intense grasshopper infestations in a
large part of the State. These pests again were by far the domin-
ant injurious insects, and their numbers were tremendous.

During the past three years, flights of the lesser migratory
locust (Melanoplus mexicanus Sauss.) have been one of the out-
standing biological phenomena of this region. This species, which
is known to have migratory tendencies, has been comparatively
quiescent in the State for many years, and the migrations which
occurred were of small proportions and for short distances. As was
reported in the Twenty-Seventh Report of the State Entomologist1
the native populations of all species of grasshoppers in the State
were at a low ebb in 1938. On the first day of July of that year, im-
mense numbers of the lesser migratory locust invaded the State
from the southeast, traveling as far to the northwest as Blaine,
Fergus, Petroleum, Rosebud, and Treasure counties. Large num-
bers of eggs were laid in the east-central area, involving Phillips,
Valley, Daniels, Sheridan, Roosevelt, Richland, Dawson, Wibaux,
Fallon, Prairie, Custer, Rosebud, Treasure, Garfield, and Petroleum
counties. This area was delimited by the survey of the autumn of
1938. and preparations were made to combat the hatching 'hoppers
in the spring of 1939. The control operations were complicated by
the deposition of large numbers of eggs in idle and reverted lands,
and in depleted range which was being invaded by such annual
weeds as Russian thistle and tumbling mustard.

To meet this new and unusual condition, the United States De-
partment of Agriculture, through the Bureau of Entomology and
Plant Quarantine, instituted a new program, furnishing bait, mixing,
transportation, and crews to poison infested, reverted, and range
land from which migrations might originate. This was in addition
to the usual cropland program in which bait materials were furn-

~ 'Montana Experiment Station Bulletin 366, 1939, pp. 12-16. (Out of
print. Available only in libraries.)

4 MONTANA EXPERIMENT STATION BULLETIN 384

ished to farmers. The area involved was so large, though, that great
numbers of grasshoppers reached maturity and migrated in the
fall of 1939 (figure 1) .

AREA HEAVIiy INFESTED WITH EGGS
SPRING 1939

AREA HEAVILY INFESTED WITH EGGS
SPRING 1940

Figure 1. Egg infestations (Melanoplus mexicanus) in the springs of
1939 and 1940, resulting from the invasion of 1938. Arrows show direction
of flight.

This new migration was primarily to the northwest again, and
flying 'hoppers invaded an area as far west at Toole, Pondera, Te-
ton, Chouteau, and Fergus counties. The survey in the fall of 1939
indicated that the area so heavily infested in the summer of that
year was now practically devoid of these pests, while an area in-
volving Phillips, Blaine, Hill, Liberty, Toole, Pondera, Teton, Chou-
teau, and Fergus counties which had received the migration, was
heavily infested with eggs. Hill County, which had an infestation of
83 per cent, was the most heavily infested county ever recorded in
the country.

Fortunately, practically all of the eggs were laid in crop and
idle land, and the range did not present the problem which it did
in east-central Montana in the summer of 1939. The special Feder-
al program was again in operation during the 1940 control season
but was largely limited to the treatment of roadsides. The hatch
in the spring of 1940 was well indicated by the previous fall's sur-
vey, but the intensity of the hatch was not forseen.

Migrations commensurate with those of the summers of 1938
and 1939 did not occur during the summer of 1940, although there
was a great deal of general movement. The 'hoppers were in a

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 5

mood to fly, and did infest parts of Toole, Pondera, Teton, Wheat-
land, Golden Valley, Musselshell, Rosebud, Petroleum, and possibly
Valley, which were not so heavily infested during the summer. This
lack of mass flight for considerable distance was probably due to
the weather conditions during the flight period, and to the great
reduction in populations as a result of the intensive control pro-
gram.

It is interesting to note that the migration of 1938 invaded an
area in which grasshoppers were on the decline and that there were,
considering the State as a whole, fewer of them in 1940 than in 1939.
They were apparently able to hold up their populations primarily
on the strength of the immense numbers present even though condi-
tions were not the best for their increase.

MAJOR INSECT CONTROL PROBLEMS

Grasshopper Control in 1939

The unusual conditions prevailing during 1939 in the badly in-
fested area in eastern Montana were (1) high infestations on deplet-
ed range, (2) almost a pure infestation of Melanoplus mexicanus,
(3) a hatch almost two weeks earlier than was expected, (4) an ex-
tremely even hatch, (5) uniformly excellent kills with poison bait,
and (6) high local interest in the control campaign. While there
was a high incidence of egg predation by bee fly and blister beetle
larvae, the large numbers of eggs which remained produced exces-
sive populations. In irrigated valleys the two-striped grasshopper
(Melanoplus bivittatus) appeared locally in some numbers, and
along fence rows and roadsides in Judith Basin and Fergus counties
they were moderately abundant. There was very little hatch until
May 5th, when a spontaneous hatch occurred in parts of Prairie,
Custer, Rosebud, Dawson, McCone, and Richland counties. In sur-
rounding areas the appearance of nymphs was delayed a little. The
evenness of the hatch was demonstrated by counts made in the area
the fourth week in May. At that time 68.9 per cent were in the
second instar, 23.3 per cent in the first, and 7.7 per cent in the third,
with over 90 per cent of the eggs hatched. A great deal of -rain
fell for about three weeks beginning May 19th. The counties east
of a line drawn through Carbon and Phillips counties had received
100 per cent of their normal rainfall for the April to August period
by the last of July, and most of Valley, Daniels, Sheridan, and
Roosevelt counties had received 125 per cent of the normal. Baiting
operations were stopped, but conditions were such that some peri-
odic feeding kept most of the 'hoppers alive. Mild migration move-
ments were first noted on the 25th and 26th of June, and they con-
tinued until the latter part of July.

In 1937 the big-headed grasshopper (Aulocara elliotti) was sec-
ond only to M. mexicanus as the dominant species in the State. In

6 MONTANA EXPERIMENT STATION BULLETIN 384

1938 its numbers along with range species with which it usually as-
sociates, were negligible.

Disease was a factor in the reduction of numbers of the two-
striped grasshopper, and sarcophagid flies were locally abundant
throughout the infested areas.

In spite of crop losses amounting to $2,867,923, the campaign
was in many respects very successful. Cooperation among all of

the agencies involved was excellent, and the interest of the farm
operators high. It is estimated that $6,835,758 in crops were saved

as a result of the campaign. Bait usage by counties is given in
table 1.

TABLE 1. — BAIT USAGE (DRY WEIGHT) BY COUNTIES, 1939-1940.

County 1939 1940

Tons Tons

Beaverhead 2.5 3.1

Big Horn 8.1 25.75

Blaine 882.5 2,976.98

Broadwater 2.0

Carbon .6 ■

Cascade 110.5 353.0

Chouteau 351.0 3,209.0

Custer-Powder River 573.35

Daniels 1,342.0

Dawson 1,838.5

Fallon-Carter 173.0 43.0

Fergus 252.25 4,786.0

Flathead 19.0

Gallatin 12.25 4.45

Garfield 1,059.9

Gla.cier .75

Golden vSiey-Muss^ 34.0 37.10

Hill 160.0 6,810.0

Jeff Orson

Judith Basin '"]"""]~"[~[]~l~[]l"~~ZZ^]Z"""""[""Z"Zll 135. 6 1 65. 05

Lake 39.0 1.0

Lewis and Clark 3.0 25.25

Liberty 20.0 1,483.7

Madison 2.0

McCone 2,437.6

Meagher 1.45

Missoula 4.5

Petroleum ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ'. 39.0 .6

Phillips 237.5 536.0

Pondera 58.0 588.0

Powell 1.0

Prairie 740.75

Ravalli 5.0

Richland 4,884.0 .5

Roosevelt 5,474.5 40.0

Rosebud 870.0

Sanders 9.0

Sheridan 543.0

Stillwater 2.5 6.50

Sweet Grass .2 4.75

Teton 71.0 550.0

Toole 120.0 232.0

Treasure 281.0

Valley 3,599.0 6.0

Wheatland 4.0 8.0

Wibaux 523.5

Yellowstone 6.0 67.75

Total 26,909.88 21,988.23

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 7

Grasshopper Control In 1940

Again in 1940 the dominant species in the State was the lesser
migratory locust. It is estimated that an intensive educational
campaign, carried on during the preceding winter mainly by coun-
ty agents, was successful in reaching approximately 7,500 people
personally, and the farm operators in the badly infested area in
north-central Montana were ready when the hatch began. Little
'hoppers appeared earlier again in 1940 than was anticipated. They
were first seen about May 11th, and by the 20th some injury was
evident. Nymphs appeared in light soil above Gildford in Hill
County before any were noted anywhere else along the upper tier of
counties. The rush on the mixing stations was almost explosive, a
comparatively large amount of bait materials on hand in the crit-
ically infested counties was soon exhausted, and for a short period
sawdust was not received in sufficient quantities to supply the great
demand. As soon as shipments were adjusted no further trouble
was experienced with shortages in bait materials.

Some disease in M. bivittatus and M. packardi was noticed, and
sarcophagid flies were moderately abundant in local areas.

The 1940 campaign was successful in saving an estimated $7,012,-
763, and losses were estimated to amount to $2,155,631. Other than
for a temporary shortage of sawdust mentioned previously, the
campaign was comparatively smooth-running, cooperation among
all agencies involved was excellent, and the interest of the farmers
high in the badly infested area.

Bait usage by counties for the 1940 season is given in table 1.

Preparation and the Success of Grasshopper Campaigns

It has been amply demonstrated during the past three years
that the success of a grasshopper control campaign is directly pro-
portional to the preparation for it, both in the field of education and

TABLE 2.— LOCAL CONTRIBUTIONS AND PARTICIPATION, 1939-1940

1939 1940

Number of mixing stations 57 37

Average weight (wet) per sack 80 80

Counties actively engaged 21 10

Farmers using bait 9,588 5,250

Average farmers per county 457 525

Wet bait used 38,479 32,980

Mechanical bait spreaders 2,891

Cropland baited (acres) 1,272,289 2,119,451

Range or pasture baited (acres) 1,021,623 86,558

Estimated losses - $2,867,923 $2,155,631

Estimated savings $6,835,758 $7,012,763

in maintaining quantities of materials at strategic places previous
to the actual field work. In 1938, when there was no warning that
the counties in eastern Montana would be invaded, and practically
no preparation was made for the influx from the southeast, crop
losses for the State were estimated to be $6,831,090, and the savings

MONTANA EXPERIMENT STATION BULLETIN 384

about one-seventh of that amount, or $940,924. In 1939 preparations
were made in advance for a strenuous campaign, and in spite of dif-
ficult complicating factors, the savings were estimated at $6,835,758,
and the losses considerably less than half of that amount, or $2,867,-
923. Again in 1940 there was warning of the possibility of a diffi-
cult situation in north-central Montana, and extensive preparations
were made to meet the condition. The savings amounted to an esti-
mated $7,012,763, and the losses were less than a third of that
amount, or $2,155,631 (table 2).

In order to make preparations to meet such emergencies, the
annual grasshopper survey is the most valuable field tool at our dis-
posal. The accuracy of prediction, as to areas involved, has been
increasing from year to year. It has been obvious, however, that er-
rors have been large on the basis of predicting the amount of bait
which may be used in a county. There are so many variable factors
which affect the amount of bait which may be used (weather, inten-
sity of infestation, availability of outside assistance, cooperation of
involved agencies, ability of personnel, use of cultural methods,
natural control, time and evenness of hatch, flights, species in-
volved, survey adequacy, type of farming, etc.) that wide differ-
ences between bait prediction figures and bait usage figures are to
be expected.

600

u500
co

Zi

c

co 400

PREDICTED

Co
O
O

u.

0 200

1—
z
u
0

0^

0

a 100

Ul

0

0

Q.

0-9.9

10-19.9 20-293 30-39.9 40-49.9 50-59.9 60-69.9 10-19.9 80-89 9
AVERAGE PER-CENT INFESTATION BY 10 PER-CENT GROUPS

Figure 2. Correlation between percentage of predicted bait used and the
intensity of infestation. Montana counties, 1937 to 1940.

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 9

During the last two years a general correlation has been noted
between the intensity of the infestation and the percentage of the
predicted bait which is used. When the per cent infestation (the
per cent of cropland which may need baiting) in a country is low,
the bait usage is correspondingly low, and when the per cent in-
festation is high, much more than the predicted amount may be
used (figure 2) . This general observation led to the compilation of
data in an endeavor to ascertain the inclusiveness of this correlation
in counties exhibiting all variations in percent infestation. The per
cent infestation for all infested Montana counties, together with the
per cent of the predicted bait used, was tabulated for 1937, 1938,
1939, and the north-central counties for 1940. The per cent infesta-
tions were averaged in 10 per cent groups, and the per cent of pre-
dicted bait used, on this basis, is given in the table below:

Per Cent Infestation No. Times Occurring Per Cent of Prediction
Used

0 to 9.9 17 88.3

10.0 to 19.9 31 70.8

20.0 to 29.9 34 110.9

30.0 to 39.9 14 139.8

40.0 to 49.9 8 231.9

50.0 to 59.9 6 523.7

60.0 to 69.9 1 136.0

70.0 to 79.9 0

80.0 to 89.9 1 486.0

The progression calculated in this table appears superfically
to be satisfactory until the 60.0 per cent to 69.9 per cent group is
reached. This group and the ones following include so few samples
that no significance could be attached to them. It is likely that a
larger number of samples in the first three groups would bring the
percentage of predicted bait which was used lower than those given
above.

While there seems to be a good correlation between these two
factors when averaged in 10 per cent groups, the data indicate a
great deviation on both sides of the mean, and it will take more data
than are at hand to put this correlation on a sound basis.

In order to discover the effect of climate and geography on this
correlation, the data were compiled for counties west of the Divide.
During the period under study these counties consistently used less
than the predicted amount of bait regardless of the per cent infesta-
tion obtained from the survey.

If this study has a value it will be in allowing an intelligent
change in the method of calculating the amounts of bait needed. It
should indicate the amount of correction necessary in different
ecological habitats infested with injurious numbers of grasshoppers.
It may necessitate a division of the chronically infested areas re-

10 MONTANA EXPERIMENT STATION BULLETIN 384

gardless of State lines, and preparations for campaigns may have to
be made on such an area basis rather than on a county basis.

Mormon Cricket Control 1939-1940

The period of 1931-1938 marked the most extensive Mormon
cricket invasion of crop areas ever recorded in the State. The
seriousness of the situation has greatly decreased in the last two
years. During 1938 the infestation reached its peak, with an estimat-
ed 2,209,078 crop acres and 5,542,407 range acres infested. Most of
these 7,751,485 acres were quite thickly populated with crickets. In
1939 there was a decrease of approximately 74 per cent in infested
cropland and 43 per cent on the range. In 1940 still another de-
crease was noted; infested crop areas were reduced 69 per cent and
range 38 per cent. Comparison of the peak infestation of 1938 with
the condition at the end of the 1940 campaign indicated a two-year
reduction of 78 per cent on cropland and 84 per cent on the range,
giving a total reduction for all infested acres of 81 per cent (table 3) .

TABLE 3.— DECREASE IN MORMON CRICKET INFESTATION 1938 TO 1940

1938 to 1939 1939 to 1940 1938 to 1940

Average Average Average

decrease % decrease % decrease %

acres decrease acres decrease acres decrease

Crop 1,626,258 74 218,800 69 1J3457058 78

Range 1,715,007 31 2,628,300 38 4,343,307 84

Total ... 3,341,265 43 2,847,100 65 6,188,365 81

Several factors probably are responsble for this decrease in in-
festation. It is apparent that control work is responsible for a good
deal of the reduction. Besides the destruction of tremendous num-
bers of crickets by the use of dust, bait, and oil and metal barriers,
there are indications that when the crickets are disturbed a large
number of the eggs which they lay will not hatch. Climatic condi-
tions in all likelihood play an important part, although it is not
known what conditions affect the crickets adversely. In past years
parasites and predators have been important agents in reducing
populations of crickets. In most areas in the State the egg para-
site, Sparaison pilosum Ashm., has been noted in increasing num-
bers for several years, and large numbers of parasitized eggs have
been collected. The sphecid predator, Palmodes laeviventris Cress.,
has been increasing in numbers, and was very abundant in certain
areas in 1940. Field mice habitually dig out the eggs and eat them.
In one area where the eggs were concentrated the mice had de-
stroyed 43 per cent of the eggs. When crickets are available, various
species of birds feed extensively on them. As many as 53 hawks
(probably Swainson's and the red tail) have been seen preying on a
single band in Beaverhead County. An examination of regurgitated
hawk pellets disclosed a large number of cricket legs, and other
indigestible heavily sclerotized parts. Other birds which were no-

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 11

ticed feeding extensively on these insects were crows, magpies,
sage hens, Brewer's blackbirds, meadow larks, horned larks, and
lark buntings. In many cases the bands of crickets could be locat-
ed by the flocks of birds hovering over them. It has also been ob-
served that coyotes and skunks eat large numbers of the pests.

Control in 1939. — The 23 counties participating in the 1939 cam-
paign were Big Horn, Blaine, Carter, Carbon, Cascade, Chouteau,
Custer, Fergus, Gallatin, Golden Valley, Hill, Judith Basin, Lake,
Meagher, Musselshell, Park, Phillips, Powder River, Rosebud,
Sanders, Stillwater, Sweet Grass, and Yellowstone. The pro-
gram was on a crop-protection basis with most of the work being
done on or within five miles of cropland. In isolated areas, how-
ever, crickets were occasionally controlled to rid a county of an in-
festation. In most of the above counties the program was very suc-
cessful, and populations were reduced by the campaign and natural
factors to such an extent that no control work was necessary in 1940.

Control in 1940. — The 1940 control program was carried out on
the same basis as the previous one. There were only five counties
involved, Big Horn, Chouteau, Judith Basin, Sanders, and Yellow-
stone having infestations severe enough to make control work ne-
cessary. It is doubtful if control work will be necessary in Chou-
teau, Judith Basin, and Yellowstone counties in 1941. In the fall
of 1940 a large migration entered Beaverhead County from Idaho,
and there has been some increase in Meagher County (table 4) .

TABLE 4. — MORMON CRICKET CONTROL ACTIVITIES

1939 1940

Crop savings $489,215 $99,840

Crop losses 16,280 125

Acres protected 235,885 72,123

Acres injured 13,268 75

Crop acres infested 582,820 364,020

Range acres infested 3,827,400 1,199,100

Total infested acres - 4,410,220 1,563,120

Acres dusted 107,207 16,052

Acres baited 4,567 5,663

Equipment and materials used

Hand dusters 439 92

Power dusters 79 30

Mixed dust (pounds) 516,293 83,301

Mixed bait (pounds) 93,540 108,120

Oil barrier (miles) 114.8 0

Oil (gals.) 36,831 0

Metal barrier (miles) 150.9 3

OTHER IMPORTANT INSECTS OF 1939 AND 1940
Clover Insects

The past two years have been marked by an increase in damage
caused by clover insects in the Flathead district, and the damage
which they have caused has run into several hundred thousand
dollars. The important insects involved were the clover seed
midge, the clover root borer, and clover aphids.

12 MONTANA EXPERIMENT STATION BULLETIN 384

Clover seed midge (Dasyneura legumincola (Lint.) ) . — The first
and only record of this insect in the State until the present was of
an outbreak at Arlee in 1917. In both 1939 and 1940 its attack on red
clover in the vicinity of Ronan, Lake County, greatly reduced the
seed yield of this important crop. Its attack is characterized by the
failure of the florets to open and by the later absence of seed. Tiny
pink or orange larvae may be found in the injured clover heads.
The winter is spent in the larval stage in the soil. In the early
spring these larvae pupate and in May or June emerge as tiny
midges which are slate gray with reddish abdomens. The eggs are
laid about the calyx and the hatching larvae enter the flowers.
When they are full grown they fall to the ground, usually during
a period of rain, and complete the cycle. There are usually two
generations. To control these insects the clover should be cut a
little before the uninjured heads have reached full bloom, and all
volunteer clover should be eliminated. This destroys the larvae
which would otherwise develop into the second generation of adults,
and usually allows ample time for the second growth to produce
seed.

The clover root borer (Hylastinus obscurns (Marsh) ) . — This is
also present in the Flathead area. The main injury caused by this
beetle results from the tunneling of the white, legless larvae in the
roots (figure 3) . The plants thus attacked wilt, turn brown, and fin-
ally die. Although this insect may attack several cultivated leg-
umes, including alfalfa and sweet clover, it prefers red and mam-
moth clover. This insect does not usually injure stands which are
one or two years old, doing the most of its damage to older fields.
When any quantity of injury is noticed in the fields, (intense in-
jury is not common) , the only control recommended is to plow
under the crop.

The clover aphid (Anuraphis bakeri Cowen). — This aphid has
been abundant in the same area as the two insects discussed above,
during 1939 and 1940. Although the plants may not be greatly in-
jured by the feeding of this insect, the seed crop losses may be great
because of its secretion of honeydew which mats the heads and
cakes the seeds in storage. Close pasturing early in the season or
cutting the first crop close to the ground and promptly removing the
hay may allow a seed crop to be produced comparatively free from
the damage which this insect causes.

Grain Insects

During the last biennium the requests for information concern-
ing the control of insects infesting stored grains have increased con-
siderably over previous years. Although the action of many of
those sent in or collected by members of the staff may not actually
injure the grain in which they were found, their presence may result

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 13

Figure
root borer.

3. Root of red clover showing tunnels and white larvae of clover

in dockage when it is sold. Those which have come to our atten-
tion recently are listed below:

Granary Weevil (Sitophilus granarius (L.) ) . — This insect, a lit-
tle smaller than a grain of wheat, is a brownish-black weevil. It
is widely distributed throughout the world, and seems to prefer a
temperate climate. The little white legless larvae hollow out the
inside of the wheat kernels, and may be extremely injurious to stor-
ed grains in the State. This pest has been reported from Belgrade,
Billings, Brussett, Chinook, Custer, Deer Lodge, East Helena, Flat-
head County, Fromberg, Hardin, Havre, Joliet, Jordan, Melstone,
Miles City, and Plains.

14 MONTANA EXPERIMENT STATION BULLETIN 384

Sawtooth Grain Beetle (Oryzaephilus surinamensis (L.)). —
This is a slender, flat, light- to dark-brown beetle which is also
world-wide in its distribution. The sides of the thorax bear a num-
ber of saw-tooth-like projections, from which the insect gets its
common name. Both in the larval and adult stages it attacks grain
and grain products, but it is not so important a pest as the granary
weevil. It has been found in the State in Belgrade, Billings, Boze-
man, East Helena, Missoula, and Ronan.

Flat Grain Beetle (Laemophloeus sp.) . — This is the smallest of
the grain-infesting insects which has been found in the State. It
is about one-sixteenth of an inch long, flat, elongate, and reddish
brown. It apparently cannot live in sound grain, usually following
up the damage caused by other grain insects or infesting grain or
meal which is out of condition. The genus has been found infesting
grain or grain products at Belgrade, Billings, Chinook, Havre, and
Hardin.

Broad-Horned Flour Beetle (Gnathocerus cornutus (F.) ) . —
This beetle is about one-sixth of an inch in length. It gets its name
from the mandibles of the male which extend in front of the head
conspicuously and curve inwardly. It is reddish brown in color. It
may be found in grain but prefers meal or flour. Although it is
found throughout the world, it is comparatively rare in the Great
Plains region and in Montana we have a single record from Deer
Lodge.

Confused Flour Beetle (Tribolium confusum Duv.). — The con-
fused flour beetle is a shiny, reddish-brown beetle, flattened and
oval in shape, about one-seventh of an inch long. It is a very general
feeder on grain and grain products, and is probably the most import-
ant and destructive of the pests attacking flour in the United States.
It may be found wherever grain or grain products are stored, es-
pecially in flour mills and in homes. We have records of extreme
abundance in houses in various parts of the State. It is generally
distributed over the world, and has been reported in Montana from
Bozeman, Butte, Forsyth, Great Falls, Missoula, Redstone, Turner,
and Wolf Point. Accidental ingestion of these pests by humans
is not an uncommon occurrence. Investigations recently reported1
from the Montana Agricultural Experiment Station indicate that
cooked confused flour beetles in all stages when consumed in oat-
meal are not injurious to humans, even when eaten in rather large
doses.

Foreign Grain Beetle (Ahasverus advena (Waltl.) ) . — This tiny,
robust, reddish-brown insect seldom if ever attacks clean, dry grain.
It is, therefore, not an important pest in stored grain, preferring
damp mouldy material and feeding on the moulds present. It is
widely distributed throughout the world, but in Montana has been
found only at Amsterdam, Custer, and Billings.

1Mills1 H. B. and Pepper, J. H., J. Econ. Ent. Vol. 32, No. 6. pp. 874-875,
1940.

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 15

Mealworms (Tenebrio molitor L. and Tenebrio obscurus F.) . —
Of these two large grain insects, the yellow mealworm (T. molitor)
appears to be more common than the dark mealworm (T. obscurus)
in Montana. The adults are over one-half of an inch long, ellipti-
cal in shape, without the strong body constriction which is notice-
able in the cadelle. The yellow mealworm adult is shiny and dark
brown to black. The adult of the dark mealworm is similar in size
and shape but is dull pitchy black in color. The larvae are elongate,
cylindrical, shiny, about an inch long, yellowish in the yellow meal-
worm and darker in the other species. They breed in refuse grain
and coarse cereal and mill products, and are partial to moist situa-
tions. There is but one generation a year and, as they feed exter-
nally upon grains, they may be easily removed from grain by fan-
ning and screening. The j'ellow meal worm has been reported from
Bozeman, Culbertson, Darby, Dillon, Florence, Great Falls, Ham-
ilton, Hardin, Helena, Joliet, Kalispell, Malta, Miles City, Missoula,
and Wibaux. The dark mealworm is known from Bozeman, Great
Falls, Hardin, and Hill County.

Cadelle (Tenebroides m,auritanicus (L)). — One of the larger
grain pests, the Cadelle is about one-third of an inch long, oblong,
flattened, and black with a conspicuous constriction between the
thorax and the abdomen. The larva is chalky white, fleshy, and
three-quarters of an inch long when full grown. The tip of the abdo-
men ends in two dark horns. Both the larva and the adult feed on
grain and grain products, and often devour only the germ from the
kernel. In Montana there are records of its occurrence in Great
Falls and Hardin.

Meal moth (Pyralis farinalis L.). — The adult of this pest is a
rather fragile looking moth with a wing spread of approximately an
inch. The forewings are characteristically marked with deep brown
bases and tips, these areas being separated from the irregular inter-
mediate straw-colored stripe by white lines. The underwings are
brownish gray, which coloration may be broken into spots toward
the hind margin. The whitish larva becomes about an inch long
when full grown. It spins a tube as it develops, and trails a silken
thread behind it wherever it goes. This webbing is conspicuous in
grain which is heavily infested or which has supported this pest
for some time. It is a general feeder in grains, cereals, and is
sometimes found in hay or other dried vegetable material. It pre-
fers damp materials and is often abundant where grain or grain
products are allowed to accumulate. The larvae, which may be
tinged with orange at both ends, may gnaw through sacking and
cause such materials to spill. There are records in the Montana
Insect Pest Survey of its occurrence near Culbertson, Forsyth,
Hardin, Kremlin, and in Garfield County.

Mediterranean Flour Moth (Ephestia kuehniella Zell.). — The
larvae of this small greyish moth may be found infesting accumu-
lations of flour, meal, or waste grain, webbing the material to-

16 MONTANA EXPERIMENT STATION BULLETIN 384

gether. When they are full grown they are about one-half inch
long and white or slightly pink in color. Not especially abundant
in Montana, this species has been reported from Bozeman, Hardin,
Miles City, and Moore.

Indian Meal Moth (Plodia interpunctella (Hbn.)). — The adult
of this species is a conspicuously marked little moth. The outer
two-thirds of the forewings are copper brown, and the inner
third is whitish gray. The wings expand to about three-fourths
of an inch. The larvae, when fully developed, are about one-half
of an inch in length and are dirty white with occasionally a green-
ish tinge. They web the materials which they infest and may
feed on grain, grain products, dried fruits, nuts, and similar food
stuffs. They have been reported from Billings and Bozeman in
the State.

Control of Grain Insects

Damage from grain insects may be greatly reduced if protec-
tive measures are taken to prevent infestations. Bins in which
grain is to be stored should be thoroughly cleaned before new grain
is stored. New bins should be so constructed that they are off
the ground, and that grain cannot accumulate beneath the floor,
between walls, etc. Dry grain should be stored, and there should
be good ventilation; it is said that grain containing seven or eight
per cent moisture is too dry and hard for most insects and that
several cannot exist in flour containing eleven per cent or less
moisture. Steel or concrete bins are more desirable than wooden
structures. Old grain sacks should not be stored near granaries
and should not be used again until they have been fumigated or
otherwise freed of live insects.

Stored grain which has become infested with grain pests is
best treated by fumigation, and carbon disulphide is the most econ-
mical and efficient material which can be used for this purpose.
This compound is a colorless, rapidly evaporating liquid, which is
approximately one-fourth heavier than air (1.26:1). If properly
applied to the top of a bin it penetrates downward, killing the in-
sects without injuring the grain. It should be remembered that
carbon disulphide is inflammable and under certain conditions ex-
plosive. Even lighted cigars or cigarettes should be kept away
from a building being fumigated with this material. The bin to be
treated should be made as tight as possible, and one pound of carbon
disulphide should be used for every 100 cubic feet or 80 bushels of
grain. Shallow pans may be imbedded in the surface of the grain
and the liquid poured into them and allowed to evaporate, or it
may be poured over old sacks or blankets thrown into the bin.
Fumigation should not be attempted at temperatures below 60°F.
U. S. D. A. Farmers' Bulletin 1483 gives further information on
this subject.

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 17
MISCELLANEOUS RECORDS AND OBSERVATIONS

Say's Plant Bug (Chlorochroa sayi Stal) . — This bug has been at-
tacking grain crops primarily in north-central Montana every year
since 1932. Its attacks have fluctuated in intensity and in localities
involved from year to year, sometimes being very destructive local-
ly. Other than in the Triangle area, where it was first noticed in
injurious numbers, and where it has been a problem ever since,
it has been seen damaging wheat south of Hardin, on Rosebud

Figure 4. Eggs of Say's plant bug on Russian thistle, the common spring
host for this pest. Enlarged about 3 to 4 times.

Creek in Rosebud County, and near Savage. This insect overwin-
ters in the adult stage beneath mats of weeds, straw, etc., and has
a spring generation primarily on Russian thistle and tumbling
mustard. Anything which can be done to destroy the hibernating
quarters will reduce the overwintering populations, and an ef-
fort should be made to return to grass reverted fields upon which
annual weeds are growing (figure 4) .

Grass Plant Bugs. — But one instance of movement of the grass
plant bug (Labops hesperius Uhler) into wheat has been observed

18 MONTANA EXPERIMENT STATION BULLETIN 384

during the past two years. In 1939 these insects invaded a wheat
field on Reece Creek north of Bozeman, causing the usual mottling
of the leaves. The wheat was about eight inches high at the time,
and soon outgrew the damage. Conostethus americanus Knight
has not been reported as injurious since 1938.

The Potato and Tomato Psyllid. — A survey was made June 19-
27, 1939, of all Montana potato areas except those in Flathead and
Lake counties. Specimens of Paratrioza cockerelli (Sulc) were col-
lected in Lewis and Clark, Cascade, Blaine, Phillips, Valley, Rich-
land, Dawson, Custer, Rosebud, Yellowstone, Carbon, and Still-
water counties. Despite the presence of psyllids at this early date,
the subsequent 1939 psyllid losses dropped far below those of 1938.
In many parts of the State light psyllid infestations were obscured
by heavy Rhizoctonia infections which were very prevalent. How-
ever, slight potato losses directly attributable to Paratrioza cock-
erelli were observed at Trident in Gallatin County, at Malta in
Phillips County, and in the Yellowstone Valley (Park City, Bill-
ings, Huntley, Custer).

A survey was made June 22-27, 1940, of potato plantings in
the eastern two-thirds of Montana. Neither adults nor immature
stages of Paratrioza cockerelli were found west of a line connect-
ing the western borders of Phillips and Yellowstone counties.
Adult Paratrioza cockerelli were collected in Phillips, Valley,
Richland, Dawson, Custer, Rosebud, Big Horn, and Yellow-
stone counties. Subsequent summer observations of infestations in
Yellowstone County snowed a gradual increase in populations of
psyllids until harvest time, afer which a general migration oc-
curred to tomatoes, egg plant, and peppers. Slight losses in po-
tato yields, unnoted by growers, probably resulted from these
infestations. A few farmers sprayed their potatoes (1 gal. liquid
lime sulfur testing 28° Baume, in 35 gallons of water) early in
the season as a precautionary measure. No reports of psyllid
damage were received from growers in the State.

Pear Psylla. — The pear psylla (Psyllia pyricola Forst.) is a
small, pale-orange to reddish-brown sucking insect. It is one of
the most important pests of the pear. When abundant, the leaves
turn brown, the fruit drops prematurely or is of poor quality, and
both the leaves and fruit may be covered with sticky honeydew
which the insects produce. This insect was introduced into Con-
necticut from Europe in 1832 and has spread over the eastern
states. Recently it was introduced into the Spokane area in Wash-
ington, and it now presents a threat to the western part of Mon-
tana at least. Ravalli, Missoula, Lake, Flathead, and Sanders
counties were surveyed from July 23rd to 30th to discover wheth-
er or not the insect had reached the State. The following is a
tabulation of the results of the survey:

TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 19

County

No. premises
examined

No.
Bartlett

trees by
Flemish

variety

Unknown

No.

times psylla

collected

Ravalli

Missoula

34

11

56
21

53
0

11
141

3
26
61
12

1
103

74

9
18

5

10
116

0

0

Lake

13

0

fathead . ..
Sanders

Total ..

3

12

73

0
0
0

It is likely that this insect does not at present exist in the
State. Any of the symptoms mentioned above occurring on pears
should be reported and specimens sent immediately to the State
Entomologist, Bozeman, Montana.

Lettuce Root Aphis. — During the first week in August 1940,
a report was received of injury being suffered by a large plant-
ing of head lettuce in the Gallatin Canyon. An examination of
the field revealed a large population of root lice attacking pri-
marily the second planting. This insect was identified through
the kindness of Miss M. A. Palmer as Pemphigus bursarius Lin-
naeus. The planting most heavily attacked was practically a
complete loss; the rest of the field was heavily irrigated for some
time after the discovery of the insects, and, although they were
present on the last two cuttings, the damage noticed was small.

Spruce Gall Lice. — Cooley's spruce gall louse (Adelges cool-
eyi Gill.) is abundant throughout the State both on native and
ornamental trees. There seems to be an individual susceptibility
in stands of Engelmann spruce (Picea engelmanni) , some trees
being heavily infested, and others close by practically immune.
It has been noted further that black hill spruce (Picea glauca al-
bertiana) and Norway spruce (Picea excelsa) are more heavily
infested than native forms. Another spruce gall aphis (Pineus
pinijoliae (Fitch)) was found attacking Engelmann spruce
at the head of Squaw Creek, Gallatin County, June 26, 1940, at an
elevation of approximately 9000 feet. The terminal gall caused
by this insect differs from the gall of Cooley's spruce gall louse
in being composed of flat scales, giving it a cone-like appearance.
(See figure 5). This species has not as yet been recorded as
damaging ornamentals in the State.

Although research on the control of the spruce gall louse in
Montana is not complete, good control has been obtained in other
parts of the country. A spray consisting of one quart of 40 per
cent nicotine sulphate and five gallons of miscible oil to 200 gal-
lons of water has been found to be satisfactory. The spray is
applied in the spring when the young are hatching from the
cotton-covered egg masses and colonizing the new growth.

Striped Cucumber Beetle. — This pest of cucurbits (Diabroti-
ca vittata (Fabr.)) was neither reported nor collected in 1939,
although in 1938 distribution included Daniels, Roosevelt, and Yel-

20

MONTANA EXPERIMENT STATION BULLETIN 384

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TWENTY-EIGHTH REPORT OF THE STATE ENTOMOLOGIST 21

lowstone counties. No cucumber beetles were noticed in 1940 until
three specimens were swept from pepper and egg plants near
Billings in September and October. On Ocober 24, 1940, hundreds
of specimens were collected in a cantaloupe patch near Billings.
They were feeding on mellow cantaloupe, gouging sizable holes in
fruit which had passed a salable condition. (See figure 6). From
one to two dozen beetles were commonly found on single canta-
loupe, while fruit nearby might show no damage. Operators of
this truck garden had noted no beetles nor damaged cucurbits ear-
lier in the season.

Figure 6. Striped cucumber beetles attacking over-ripe melons.

Strawberry Root Worm. — Following an inquiry on August 8,
1940, from the horticultural inspector at Billings, a strawberry
planting west of that city was examined for insects. About 20
per cent of the several hundred plants in this field were dead. The
root system of the dead plants had suffered from the feeding of
some insect, while leaves of many living and dead plants had been
riddled by a chewing insect. Examination of the soil under the
dead plants revealed many small white grubs (about one-sixth
inch long), numerous pupae, and several small coppery beetles.
Most of these adults had four rather irregular, but distinct, black

22 MONTANA EXPERIMENT STATION BULLETIN 384

blotches on the wing covers. These specimens proved to be stages
of the strawberry rootworm (Paria canella (Fabr.) ) previously
unreported from Montana. A search in three additional strawberry
patches in this area revealed this pest in two of the three plant-
ings.

According to Essig1 these insects overwinter as adults in the
soil, coming out in April and May to feed and deposit eggs on or
near the strawberry plants. Larvae hatch from these eggs in
seven to fifteen days and feed on the strawberry roots. While
Essig notes two generations per year in California, adult emergence
dates in the latitude of Billings would suggest a single generation.

When adults are feeding in the spring and autumn, spraying
with four pounds lead arsenate to 100 gallons of water gives good
control, although this remedy cannot be applied close to picking
time. At such periods the plants may be dusted with a mixture of
sulfur and ground derris root, containing one per cent rotenone
when applied to the plants.

Red Turnip Beetle. — The red turnip beetle (Entomoscelis ad-
onidis (Pallas) ) is a moderately large beetle, about one-third of an
inch in length. In shape it somewhat resembles the Colorado po-
tato beetle, but it is predominantly red with dark areas on the
head and pronotum, and three dark stripes on the wing covers. It
feeds at night on cabbages, radishes, turnips, and other related
plants. Its range extends from Europe through Siberia into the
northern part of North America. Although it has been found in
the Bridger Mountains, Glacier Park, and at Lombard, it was not
reported as injurious until the summer of 1940, when it damaged
gardens in and around White Sulphur Springs. It should be con-
trolled easily by the use of usual stomach poisons such as lead ar-
senate.

Soft-winged Flower Beetle. — This little beetle (Malachius
aeneus (L.) ) was first found in Montana at Bozeman in the spring
of 1938 and in 1940 it was not uncommon; a specimen was taken
in Madison County near Pony, in the summer of 1940. It is about
one-fifth of an inch long, most of the head and prothorax, a V-
shaped area including about two-thirds of the elytral suture, the
under parts, and the appendages are an irridescent greenish black.
The face, the prothorax laterally, and the most of the elytra are
deep red. The species was identified by Mr. H. S. Barber of the
Bureau of Entomology and Plant Quarantine who submitted the
following statement:

"Such a large, conspicuous and abundant exotic species, spread-
ing across our wheat areas, should have received some attention,
but except for records of capture in a few places, there seems to
be very little information which I can find. It is abundant in

^Essig, E. O., Insects of Western North America, 1926, pp. 468-469.

TWENTY-EIGHT REPORT OF THE STATE ENTOMOLOGIST 23

Europe and was reported in New England about 85 years ago, but
the only biological notes I find seem based upon the old note by
Perris 1852 describing the predatory larva. There is, however,
a little-known report that the adults feed upon the soft parts of
blossoms of wheat and much reduce the number of kernels formed
in a head of wheat, the injury being noticeable only by feeling the
ripened heads between the fingers to detect absence of kernels.

"The role of this species in the United States should be de-
termined by new observations on its habits, both as the phytoph-
agous adults and as the predatory larvae."

Alfalfa Weevil. — There are several old records of the alfalfa
weevil (Phytonomus posticus (Gyll.)) in the State. They were col-
lected from hay shipped into Montana from 1912 to 1914 at Ballan-
tine, Billings, Butte, and Great Falls. In 1938 and 1939 scouts for
the Bureau of Entomology and Plant Quarantine collected a few
larvae in the vicinity of Wyola. This is the only place in the
State where these insects apparently have been established.

Sugar Beet Webworm. — Only light to moderate infestations of
the sugar beet webworm (Loxostege sticticalis L.) were reported
during 1939 and 1940. A heavy moth flight took place over most
of the State during early June 1939, but due to the high per cent
of sterility among the females few eggs were laid. Moderate in-
festations necessitating spraying were reported from the vicinity
of Fromberg and also from the lower Flathead district near Ro-
nan. Relatively few fields were attacked and damage was slight.
In 1940 the moth flight was considerably smaller than during the
previous year. The only report of numbers sufficient to require
spraying was from the vicinity of Valier. A few fields in the Bill-
ings district were reported infested, but not in sufficient numbers
to warrant spraying.

Alfalfa Semi-Looper. — This looping, aerial cutworm (Auto-
grapha calif ornica (Speyer)) was last abundant throughout the
State in 1914. The only other record of the species until this year
was from Twin Bridges in 1922. In 1940 larvae were reported from
alfalfa fields near Helena, Logan, and Ronan, and a large number
of adults were flying at Bozeman during the first part of June. The
larvae are cutworm-like, but move with a looping motion similar to
measuring worms. They are very general feeders, but the most of
their damage has been reported from alfalfa. As a usual thing
they are so thoroughly held in check by parasites and disease that
they are not injurious to crops.

Army Worm. — The true army worm (Cirphis unipuncta
(Haw.) ) appeared in 1940 in a small area south of Scobey. This
insect may be a very serious enemy of many crops, especially grass-
es, but in Montana it becomes sufficiently abundant to do damage
only on rare occasions. It may be held in check by the use of grass-
hopper bait or barriers placed before migrating bands.

24 MONTANA EXPERIMENT STATION BULLETIN 384

Pale Western Cutworm. — The State has experienced several
years now with no outbreak of the pale western cutworm (Agrotis
orthogonia Morr.) . It was last important in the spring of 1937.
The abundance of this pest is dependent on the rainfall during
May, June, and July of the previous year, and it is possible to pre-
dict in advance the areas where injury may be expected. Weather
data for the spring of 1940 would indicate that it may be a minor
pest during 1941 in the Yellowstone Valley from Forsyth to Liv-
ingston, and in Golden Valley, Musselshell, central Liberty, south-
ern Lewis and Clark, and Beaverhead counties. Control measures
for this insect have been discussed recently1 and will not be repeat-
ed here.

Codling Moth. — In the apple districts of western Montana the
codling moth (Carpocapsa pomonella (L.) ) increased markedly in
1940 over any previous year. Average catches of moths in bait
traps went as high as 75.8 for a two-day period. For the first time
this pest became sufficiently abundant in the Bitter Root and parts
of the Flathead Valley to become one of the foremost problems of
the apple orchardist. Conditions during June, July, and August
were ideal, and even with good spraying programs the loss was
fairly high. However, property executed spraying programs very
decidedly paid for themselves even under conditions of a short crop.
The use of bait traps for the collection of adults as an indication
of the timing of the cover sprays is becoming more important, and
investigations into their use are being continued by Mr. Wm. R.
Forsyth, graduate assistant, who was stationed in the area in 1940.

Termites. — Two species of termites have been found in Mon-
tana, the damp wood termite (Zootermposis nevadensis (Hagen) )
which has been collected near Hamilton and doubtless has a wider
distribution west of the Divide, and the barren-land subterranean
termite (Reticulitermes tibialis (Banks)). This latter species (fig-
ure 7) is widespread in the State and occasionally damages build-
ings. It has been collected in or near the following cities in Montana:
Billings, Hardin, Havre, Helena, Jefferson Island, Kalispell, Miles
City, Powderville, Terry, and Whitehall. The workers, soldiers,
and wingless sexual forms are found in tunnels in wood which have
been excavated by the workers. This species is not a major pest
in the State, but occasionally it is extremely injurious in dwellings.
Its presence is usually first noticed because of a buckling or the ap-
pearance of holes in the floor, or the swarming of slate-colored
winged adults in the rooms. Houses as far north as Havre have
been attacked by this insect. Much has been published on the con-
trol of the termite and on the prevention of its entrance into houses.
Information can be obtained by writing to the Montana Agricul-

:Mont. Agr. Exp. Sta. Bui. 366, p. 22, 1939; Mont. Ext. Ser. Bui. 176, p.
$6, 1939.

TWENTY-EIGHT REPORT OF THE STATE ENTOMOLOGIST 25

Figure 7. Workers of the termite Reticulitermes tibialis Banks. En-
larged 7 times.

tural Experiment Station or to the Office of Information, Depart-
ment of Agriculture, Washington, D. C.

Alpine Rock Crawler. — Continued search during 1939 and 1940
for this alpine insect (Grylloblatta campodeiformis Walker) has
yielded some interesting negative and positive collection data. At-
tempts to collect Grylloblattids in the Bridger Range (Gallatin
County) on August 21, September 2, and September 10, 1939, were
unsuccessful. Specimens were found in the same general area on
September 24, 1939. After the onset of cool autumn weather, ac-
companied by fall showers, many specimens have been collected in
the Gallatin and Springhill canyons. In the Gallatin Canyon on
October 11, as well as in the Springhill area on October 17, 1940,
a pair of mating adults was found.

Earwigs. — There are no native earwigs in Montana, but two
species have been introduced. The little earwig, Labia minor L.,
has been collected twice in or near Bozeman on widely separated
dates, and is of little economic importance. In 1939 the European

2(3

MONTANA EXPERIMENT STATION BULLETIN 384

earwig, Forficula auricularia L., was first reported from the State
when specimens were collected at Thompson Falls, (figure 8) . The
abundance of this pest when first discovered would indicate that
it had been present for some time previous to 1939. In 1940 an in-
festation was reported from Lewistown, with the note that these
insects had been present for at least six years in this area.

The European earwig is an elongate, shiny brown insect, and
is easily identified by the large slender pinchers which are ap-
pended to the tip of the abdomen. It is primarily nocturnal in its
habits, hiding beneath bark, chips, and other debris during the day.
Our infestations undoubtedly came from the introduction of this
pest into Pacific ports some time ago. It is abundant in parts of
Washington, Oregon, California, and Idaho to the west.

/

Figure 8.

times.

European earwig. Male on left, female on right. Enlarged 5

This insect may be best controlled by the use of poisoned bait.
The bait recommended by the Oregon Agricultural Experiment Sta-
tion, which has worked satisfactorily, consists of

TWENTY-EIGHT REPORT OF THE STATE ENTOMOLOGIST 2?

Bran 12 lbs.

Sodium fluosilicate 1 lb.

Fish oil 1 qt.

The dry materials should be thoroughly mixed together and the
fish oil added and mixed in. No water is necessary. Sodium fluor-
ide, barium fluosilicate, or paris green may be substituted for the
sodium fluosilicate, but they are not so satisfactory. The bait
should be scattered about fences, piles of boards, wood piles, trees,
and other places where the earwigs may hide. It should be kept
away from children. Chickens and other birds would have to eat
a great deal of it to be injured.

INDEX

Page

Introduction 3

Major Insect Control Problems 5

Grasshopper Control in 1939 ....i 5

Grasshopper Control in 1940 7

Preparation and Success of Grasshopper Campaigns 7

Mormon Cricket Control 1939-1940 10

Control in 1939 11

Control in 1940 11

Other Important Insections of 1939 and 1940 11

Clover Insects 11

Clover seed midge 12

The clover root borer 12

The clover aphid 12

Grain Insects 12

Granary weevil , 13

Sawtooth grain beetle 14

Flat grain beetle 14

Broad-horned flour beetle 14

Confused flour beetle 14

Foreign grain beetle 14

Mealworms 15

Cadelle 15

Meal moth 15

Mediterranean flour moth 15

Indian meal moth 16

Control of Grain Insects 16

Miscellaneous Records And Observations 17

Say's plant bug 17

Grass plant bugs 17

The potato and tomato psyllid 18

Pear psylla 18

Lettuce root aphis 19

Spruce gall lice 19

Striped cucumber beetle 19

Strawberry root worm 21

Red turnip beetle 22

Soft-winged flower beetle 22

Alfalfa weevil 23

Sugar beet webworm 23

Alfalfa semi-looper 23

Army worm 23

Pale western cutworm 24

Codling moth 24

Termites 24

Alpine rock crawler 25

Earwigs 25