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Fruit Notes 

Prepared by: Department of Plant and Soil Sciences 

Massachusetts Cooperative Extension, University of Massachusetts, United States 

Department of Agriculture and Massachusetts counties cooperating. 



Editors: W. R. Autio and W. J. Bramlage 




Volume 52,No.l 
WINTER ISSUE, 1987 



Table of Contents 

Apple Rootstock Evaluation in Massachusetts 

Pomological Paragraph: Revision of Storage Handbook 

Pomological Paragraph: Public Opinion About Alar 

Mauget Microinjection of Oxytetracycline for Therapy 
and Prevention of Eastern X-Disease of Peaches 

Strawberry Arthropod Pests: An Introduction 
to Strawberry Insect Pest Management 

Pomological Paragraph: Market Basket Survey: 
Good News for Retailers and Consumers 

Monitoring and Control of Apple Blotch Leafminer: An Update 

Pomological Paragraph: State of Maine Suspends Action on 

Mandatory Tolerances for Alar* 

Reducing Energy Costs in CA Storage 

An Economic Analysis of Orchard Rejuvenation in Response to 
the Reduction or the Elimination of the Use of Alar® 



APPLE ROOTSTOCK EVALUATION IN MASSACHUSETTS: 1986 

Wesley R. Autio 

Department of Plant and Soil Sciences 

University of Massachusetts 



With the increasing costs of land, labor, and all inputs of orchard 
production, there is a need to intensify management. The use of dwarfing 
rootstocks is one way to accomplish this while reducing some costs and 
increasing returns. However, rootstocks must be evaluated thoroughly prior to 
wide scale planting. In this paper 1 would like to present the results of two 
rootstock plantings at the Horticulture Research Center in Belchertown, 
Massachusetts. 

The University of Massachusetts has been involved with the NC-140 
Regional Research Committee for a number of years, and in 1980 and 1984 
plantings were established at about 30 locations across the country and Canada. 
The 1980 planting consists of Starkspur Supreme Delicious on Ottawa 3, M.7 
(EMLA), M.9A (EMLA), M.26 (EMLA), M.27 (EMLA), M.9, MAC 9 (Mark), MAC 
24, and OAR 1. The EMLA designation means that the source of the rootstock 
was a clone which has had the viruses removed. A similar planting of these 
rootstocks with Summerland Red Mcintosh as the scion cultivar was established 
in 1985. 

The 1984 planting includes Starkspur Supreme Delicious on Bud. 491, Bud. 9, 
MAC 1, MAC 39, P.l, P. 22, seedling, CG 10, CG 24, M.4, M.7 (EMLA), M.26 
(EMLA), Bud.490, P. 2, P. 16, P. 18, CG, and Ant. 313. Descriptions of the origins 
of the rootstocks in both the 1980 and 1984 plantings can be found in Fruit 
Notes 51(4):22-24. 

1980 Planting 

Tables 1, 2, and 3 show the sizes, yields, and amounts of suckering of the 
trees in the 1980 planting after seven growing seasons. Based on trunk 
diameter and height (Table 1), the largest trees were on MAC 24 roots, and 
they were significantly larger than those on M.7 (EMLA). Trees on MAC 9 
were similar in size to those on M.26 (EMLA). Trees on M.27 (EMLA) and M.9 
were the smallest. Interestingly, those on M.9A (EMLA) were significantly 
larger than those on M.9. 

The hypothetical number of trees per acre (Table 1) was calculated from 
tree spread. It was assumed that spacing between trees should be 40% greater 
than the present spread, and the distance between rows should be approximately 
8 feet larger than the spacing between trees. These data suggest that the 
optimal density of MAC 9 is similar to that of M.26 (EMLA). MAC 24 requires 
a very wide spacing, approximately 20 x 28 feet. 

Yield for these trees is reported in Table 2 as yield per tree and per acre 
(calculated from hypothetical tree density) for 1986 and on a cumulative basis. 
Generally, the largest trees were the most productive per tree, but the 



potential yield per acre was highest for trees on MAC 9 and M.9A (EMLA). In 
1986, on a per acre basis, trees on OAR 1, MAC 24, and M.27 (EMLA) were the 
poorest yielders. 

Table 1. Tree size and hypothetical density in the 1980 planting as measured 
on October 15, 1986 

















Hypothhtical 




Trunk 


Tree 




Tree 


number of 


trees 




diameter 


height 


spread 


per acre (+ 


approx. 


Rootstock 


(ir 


i) 


(ft) 




(f1 


:) 


spacing in 


ft.) 


Ottawa 3 


2.2 


d* 


8.4 


d 


7.4 


b 


214 (11 X 


19) 


M.7 (EMLA) 


3.2 


b 


11.2 


b 


9.0 


b 


165 (13 X 


21) 


M.9A (EMLA) 


1.8 


e 


7.4 


de 


5.4 


c 


342 (8 X 


16) 


M.26 (EMLA) 


2.5 


cd 


9.8 


e 


7.4 


b 


214 (11 X 


19) 


M.27 (EMLA) 


1.0 


f 


5.2 


f 


2.8 


d 


952 (4 X 


12) 


M.9 


1.3 


f 


6.2 


ef 


3.4 


d 


760 (5 X 


13) 


MAC 9 


2.5 


cd 


7.8 


d 


7.6 


b 


218 (11 X 


19) 


MAC 24 


5.0 


a 


14.4 


a 


13.0 


a 


83 (20 X 


28) 


OAR 1 


2.6 


c 


10.4 


be 


5.2 


c 


377 (8 X 


16) 



*Means in a column not followed by the same letter are significantly different. 



Table 2. Cumulative and 1986 yields per tree and per acre for the 1980 
plant ing. 



Rootstock 



Yield yield 

per tree per tree 

(1986) (1983-86) 

(bu) (bu) 



Potent ia 1 


Potential 


yield 


cumulat ive yield 


per acre 


per acre 


(1986) 


(1983-86) 


(bu) 


(bu) 


276 abed 


817 ab 


335 abc 


835 ab 


380 ab 


1067 a 


336 abed 


944 ab 


257 cd 


762 ab 


327 bed 


1110 a 


440 a 


1131 a 


226 cd 


623 ab 


181 d 


539 b 



Ottawa 3 
M.7 (EMLA) 
M.9A (EMLA) 
M.26 (EMLA) 
M.27 (EMLA) 
M.9 
MAC 9 
MAC 24 
OAR 1 



1.29 c* 
2.03 b 
1.11 c 
1.57 be 
0.27 d 
0.43 d 
2.02 b 
2.72 a 
0.48 d 



3.82 cd 
5.06 be 
3.12 d 
4.41 be 
0.80 e 
1.46 e 
5.19 b 
7.51 a 
1.43 e 



*Means in a column not followed by the same letters are significantly different. 



The number of suckers per tree and per acre are reported for each 
rootstock in Table 3. On a per tree basis MAC 24 resulted in many more 
suckers than any other rootstock. When the number of trees per acre were 
considered MAC 24 and M.9 produced the most suckers per acre. 

Table 3. The number of suckers per tree and potential number per acre for 
trees in the 1980 planting. 



Rootstock 



Cumu la live 


Potential 


suckers 


suckers 


per tree 


per acre 


(1980- 


86) 


(1980-86) 


0.8 


b* 


171 b 


4.2 


b 


693 b 


1.6 


b 


547 b 


5.0 


b 


1070 b 


0.2 


b 


190 b 


7.8 


b 


5928 a 


1.4 


b 


305 b 


118.4 


a 


9837 a 


2.6 


b 


980 b 



Ottawa 3 
M.7 (EMLA) 
M.9A (EMLA) 
M.26 (EMLA) 
M.27 (EMLA) 
M.9 
MAC 9 
MAC 24 
OAR 1 



"Means in a column not followed by the same letter are significantly different. 



In 1986 evaluation of fruit quality and ripening of fruit from these trees 
began. Results will be reported in later issues. 

1984 Plantin g 

The trees in the 1984 planting are not old enough for a full evaluation of 
tree characteristics, but tree size after 3 growing seasons and bloom are 
reported in Table 4. Treus on Ant. 313, Bud. 491, and seedling roots were the 
largest, and those on P. 2, P. 16, and P. 22 were the smallest. The number of 
flower clusters were counted in 1986 and the bloom is presented as the number 
of blossom clusters per unit of trunk cross-sectional area. Because of the 
significantly higher amount of bloom, trees on B.9, MAC 39, P. 22, M.26 (EMLA), 
P. 2, P. 16, and C.6 likely would fruit earlier than trees on the other rootstocks. 
Further observation of these trees will give us insight into new rootstocks 
which may perform well in Massachusetts. 



Table 4. Tree size and bloom of trees in the 1984 planting. 





Tru 


nk 










Blossom c 


lusters 




diame er 


Height 


Spread 


per cm^ 


' trunk 


Rootstock 


(in) 


(ft) 


(f 


t) 


cross-sectional area 


Bud.491 


1.59 


ab* 


7.1 


ab 


4.4 


ab 


0.03 


f 


Bud. 9 


1.23 


def 


7.1 


fg 


3.1 


bcdef 


8.87 


c 


MAC 1 


1.29 


cde 


7.3 


defg 


3.3 


abcde 


0.45 


f 


MAC 39 


1.04 


fg 


6.9 


gh 


3.1 


bcdef 


5.01 


de 


P.l 


1.47 


a be 


8.1 


bcde 


3.2 


bcdef 


3.98 


e 


P. 22 


0.78 


h 


4.7 


J 


1.8 


e 


8.24 


c 


Seedling 


1.55 


ab 


8.1 


bcde 


4.0 


abed 


1.24 


f 


CG 10 


1.49 


a be 


7.9 


cdef g 


3.9 


abed 


0.99 


f 


CG 24 


1.38 


bode 


8.2 


abed 


3.6 


abcde 


0.65 


f 


M.4 


1.23 


def 


7.6 


cdef g 


3.3 


abcde 


0.80 


f 


EMLA 7 


1.32 


cde 


7.9 


cdef g 


3.6 


abcde 


1.06 


f 


EMLA 26 


1.19 


ef 


7.1 


ef g 


2.9 


cdef 


4.51 


e 


Bud.490 


1.43 


abed 


7.8 


cdef g 


3.4 


abcde 


0.91 


f 


P. 2 


1.00 


fgh 


5.7 


ij 


2.7 


def 


4.54 


e 


P. 16 


0.85 


gh 


5.9 


hi 


2.3 


ef 


8.33 


e 


P. 18 


1.43 


abed 


8.2 


abed 


4.0 


abed 


0.65 


f 


C.6 


1.18 


ef 


6.9 


gh 


3.3 


abcde 


6.18 


d 


Ant. 313 


1.64 


a 


8.7 


a be 


4.8 


a 


0.50 


f 



'Means in a column not followed by the same letter are significantly different. 



Conclusions 



MAC 9 (sold as Mark) continues to perform extremely well under our 
conditions. Trees are similar in size to M.26. They are more stable than M.26, 
not requiring support at this point, and they are veiy productive. The other 
rootstock which shows a lot of promise is M.9A (E\LA). The source of this 
stock is derived from M.9A (a clone of M.9) after the viruses were removed. It 
is considerably more vigorous and much more productive than standard M.9. It 
could be particularly useful for plantings on posts. The additional vigor keeps 
lateral branches more upright and productive longer. 

In coming years we will be able to observe Mark with Mcintosh and 
several other cultivars in differeni plantings around Massachusetts. It would be 
advisable for growers to begin experimenting with Mark in small plantings but, 
it is too early in testing to recommend it for large-scale plantings. 



- 5 - 

POMOLOGICAL PARAGRAPH 

Revision of Storage Handbook 

William J. Bramlage 

Department of Plant and Soil Sciences 

University of Massachusetts 

The U.S. Department of Agriculture recently published a revision of its 
Agriculture Handbook Number 66, "The Commercial Storage of Fruits, 
Vegetables, and Florist and Nursery Stock." 

The handbook discusses factors that can significantly affect quality 
maintenance during storage, and is a wealth of specific information about the 
postharvest needs and problems of many horticultural crops. Anyone working 
with storage of horticultural crops should have this publication for quick 
reference to needs for storing these crops. 

Agriculture Handbook Number 66 can be purchased from the Superintendent 
of Documents, Government Printing Office, Washington, D.C. 20402. The stock 
number is 001-000-04478-8, and the price is $6.00. 



POMOLOGICAL PARAGRAPH 

Public Opinion About Alar 
International Apple Institute 



Are consumers concerned about apples? Not really, according to a 
national study conducted by Opinion Research Corporation, a San Francisco 
based market research firm. The study, conducted in July 1986, reports that 
only an estimated nine percent of the population is even aware of any publicity 
or news stories of health concerns about apples. 

A surprising number of respondents to the study replied that the news 
they heard about apples was good. In addition, many other respondents who 
remember recently hearing something about apples in the news could not even 
recall whether it was positive or negative. 

Consequently, the overwhelming majority of consumers are not concerned 
with apples and therefore, we hope retailers are not worried. 

* * « * * 



- G - 



MAUGBT MICROINJECTION OF OXYTETRACYCLINB FOR THERAPY 
AND PREVENTION OF EASTERN X-DISEASB OF PEACHES 

Terry A. Tattar, Julianno Schi>5ffer, 

and Daniel Cooley 

Department of Plant Pathology 

University of Massachusetts 

Introduction 

Peach X-disease has been considered one of tiie factors that limits 
profitability of commercial peach product ion in the Nortlieast. This mycoplasnfia 
disease has been brought into remission by trunk injection of oxytetracycline 
antibiotics (2). However, the injection met'nods used were very labor intensive 
and difficult for peach growers to use in commercial orchards (1). There also 
is some evidence that these methods have led to significant trunk dam.ige over 
time (Pierson, personal communication). Mauget (J.J. Mauget Co., 2810 So. 
Figu<;roa St., Los Angeles, CA 90065) microinjection has been used widely for 
trunk injection of shade trees by arborists to deliver f ert ili/.ers, fungicides, 
antibiotics, insecticides, and micrunutrients. Recently, a Mauget capsule //ith 
4% oxytetracycline (OTC) became available for experimental use in controlling 
myc»)plasma diseases of trees. If a simple system of trunk injtsction like the 
Mauget microinjection system could deliver oxytetracycline to peach trees 
effectively, control of X-disease in peach orchards by trunk injection could be 
performed by peach growers. The objcsct of this study was to determine if 
Mauget capsules containing 4% oxytetraoycline could be used to control X- 
disease in a commc^rcial peach orciiard. 

Materials and Methods 

Green Acres Orciiard in Wilbraham, Massachusetts was the test site for 
this study. In late summer, 1985 it was noted that a number of trees in the 
northeast corner of a 5- to 6-year-old peach block (a late variety mixture) 
vvere exhibiting sy.nijto ns (reduced apical and radial growth, greatly reduc^^d 
fruit yield, chlorotic and red-spotted foliage, prematire defoliation of inner 
leav-is, and prematare bud break) of eastern X-disease. At this time several 
trees in this corner of the block had already died and replacement trees had 
been planted. A number of other trees had one-t'nird to one-half of their 
crowns remov'id by pruning. 

Antibiotic therapy was performed in an attemjjt to save the living trees 
exhibiting X-disease sy^nptjas, and to protect a number of trees growing 
adjacent to the affected ones. The metliod cliosen for therapy was trunk 
injection with Mauget capsules, which contain 4 ml of i% oxytetra-cycline 
(OTC) antibiotic and are disposable after use. On October 7, 1985 twenty-seven 
trees were trunk injected using a dose rate of one capsul<i per two inches of 
trunk diameter, measured at approximately one foot above ground. Since most 
trees were approximately 5 to 7 inches in diameter, three capsules per tree was 
the most common dose. To place the Mauget capsule in the tree, a drill hole 
(3/16" in diameter and 1/2" dec^p) was made in the trunk approxim^i tely 2 to 4" 
aboveground. The delivery tube and capsule were inserted immediately into the 
hole. Most )f the capsules were einpty within two hours and all were empty by 
the next day when the capsules were removed. 



7 - 



Results 

In the spring of 1986 all treated trees appeared free of X-disease 
symptoms. However, in late July and August, nine of the 27 injected trees 
began to display X-disease syrrptoms. Most of these trees were the most 
severely affected trees in the fall of 1985. One of these trees died by the end 
of the growing season. The remaining 18 trees stayed in remission through 
fruit harvest and fall coloration. Fruit yields on these trees were normal. The 
wounds from the injection completely closed by the end of the 1986 growing 
season. 

Discussion 

The effect of OTC therapy on this block was a partial success, with most 
trees remaining free of X-disease synptoms in 1986. Since most of the trees 
that went out of remission were in poor condition before injection, there may 
be limited effectiveness of OTC therapy on trees in advanced stages of the X- 
disease. The Mauget capsule delivery system for the OTC antibiotic appeared to 
be an effective and sinple technique for injection therapy in this experiment. 
Additional research is needed to evaluate further this preliminary study. We 
are particularly interested in establishing levels of injury at which treatment is 
effective, and levels where treatment is not effective. 

Outlook 

The effect of Mauget injection of OTC for X-disease control currently is 
being evaluated in 5 commercial orchards in central and western Massachusetts. 
Trees in these orchards were injected after harvest in September and October, 
1986. An update of this research project will be made in the fall of 1987. 

Literature Cited 

1. Lacy, G.H. 1982. Peach X-disease: Treatment site damage and yield 

response following antibiotic infusion. Plant Disease Reptr. 66:1129 - 
1133. 

2. Sands, D.C. and G.S. Walton. 1975. Tetracycline injections for control 

of eastern X-disease and bacterial spot of peach. Plant Disease Rept. 
59:573-576. 

Acknowledgements 

The authors wish to thank Dorence Green, Steven Smedberg, and George 
Swain of Green Acres Orchards for their assistance and cooperation during this 
study. We also thank the J.J. Mauget Connpany for supplying us with the 
Mauget OTC capsules for these experiments. 

***** 



- 8 - 



STRAWBERRY ARTHROPOD PESTS: AN INTRODUCTION 
TO STRAWBERRY INSECT PEST MANAGEMENT 

Karen I. Hausohild 

Regional Fruit Agent 

Hampden County Extension Office 

West Springfield, MA 

Conpared with other fruit crops grown in the Northeast strawberries have 
relatively few insect or other arthropod pests. However, at least three of these 
pests, if uncontrolled, can devastate the crop in any given year. Although 
chemical controls are most often used, the populations of at least two of these 
pests can be controlled, to a certain extent, by non-chemical measures. 

The purpose of this article is to acquaint readers with the life histories of 
and damage caused by the major strawberry arthropod pests found in our area. 
Chemical control recommendations can be obtained from your county, regional, 
or State extension personnel. Where appropriate, non-chemical control measures 
will be outlined. 

Tarnished Plant Bug 

There are two insect species that are the most troublesome on strawberry 
buds or fruit, the tarnished plant bug and the strawberry bud weevil ("clipper"). 
Their damage results in direct fruit loss or loss of marketable fruit. The 
tarnished plant bug ( Lygus lineolaris P. & B.) is an oval-shaped, flattened bug 
about 1/4 inch long, brown in color, and mottled with irregular blotches of 
white, yellow, reddish-brown, and black. On the front third of the forewings 
there is a clear-yellow, triangular area tipped with a black triangular spot. The 
greenish or yellowish nymphs resemble adults except for their small size and 
lack of wings. Larger nyrrphs are marked with 4 black spots on the thorax and 
one on the base of the abdomen. The tarnished plant bug (TPB) has a 3 to 4 
week life cycle; therefore, three to five generations of this insect can occur in 
any one season. 

Tarnished plant bugs overwinter as adults in protected areas such as leaf 
litter, hedgerows, or even in strawberry mulch. They emerge from their 
overwintering sites early in spring and feed on developing fruit tree buds, 
weeds, alfalfa, or other crops. Apparently, strawberry is a preferred crop 
because it initiates growth early in the spring. 

Plant bugs have piercing-sucking mouthparts. As they feed they introduce 
a toxic saliva into the developing strawberry fruit. This feeding results in 
misshapen, catfaced berries, which, if abundant, seriously reduce the size and 
number of marketable fruit. The most critical time for damage appears to be 
immediately after petal fall, with less damage occurring during full bloom and 
less to none occurring during the flower bud stage. 

Although the basis for control of this pest is properly timed pesticide 
applications, there are cultura 1 practices that may help. Good weed control will 
help eliminate alternate food sources as well as egg-laying sites. Be sure to 



- 9 - 



control weeds in bordering crops and hedgerows. Since tarnished plant bugs are 
early season pests, it may be helpful to avoid planting early maturing 
strawberry cultivars if this insect is troublesome for you. 

In New York state, as few as one TPB nyntph per fruit inflorescence is 
thought to result in 30% fewer fruits with a corresponding 18% loss in berry 
weight. Therefore, it is very inportant to be aware of this insect and the 
potential for damage it can cause. 

Strawberry Bud Weevil 

The strawberry bud weevil, or "clipper" beetle, ( Anthonomus signatus Say) 
is a dark reddish-brown beetle with black patches on its wings, and measures 
about 1/10 of an inch in length. Weevils hibernate as adults in trash in or 
near strawberry fields, coming out to feed and lay eggs in the developing fruit 
buds in the spring. The female lays an egg in an unopened blossom bud then 
girdles the stem below the bud so that the bud stem breaks, wilts, and falls to 
the ground. The beetle grub inside feeds largely on the pollen of the unopened 
bud. The legless, white grub feeds for about 4 weeks then changes to a pupa 
and eventually to a weevil within the bud in which it developed. The newly- 
emerged beetles feed for a short time then go into hibernation until the 
following spring. 

Yield losses due to egg-laying damage caused by the strawberry bud weevil 
(SEW) can range from 50 to 100%. An average of one cut bud per 1.5 feet of 
row, or one female beetle found per 40 row-feet, can result in economic 
damage. 

Since strawberry bud weevils overwinter in wooded areas, preferring areas 
with early flowering species such as red bud and wild brambles, avoiding such 
areas may reduce potential SBW damage. Also, there is some indication that 
early flowering cultivars attract overwintering SBW, and therefore can be used 
as a "trap" crop. 

Because of the potential seriousness of this pest, it is inportant to watch 
for the incidence of SBW in early cultivars. Look for cut buds, or the tiny 
adults on the blossoms themelves. (Adults also feed on strawberry pollen.) 

To help control SBW, remove excess foliage and mulch from renovated 
strawberry beds immediately after harvest to discourage overwintering. If SBW 
damage has been severe, plow under strawberry beds to reduce overwintering 
populations. 

Spitt lebug 

Spittlebugs ( Philaneeus spp. ) are soft-bodied, tan to greenish, elongate 
bugs about 1/8 to 1/4 inch long. The adults have blunt heads and prominent 
eyes. Wings can be marked with spots, stripes or bands. 

Spittlebugs usually overwinter as eggs in the stems of grasses or weeds. 
Eggs hatch in the spring at about the time new strawberry leaves and flower 



10 



buds are showing. The small white nymphs settle on the new growth, and as 
soon as they start to feed they start to excrete the spittle within which they 
remain, and feed until they transform to adults. There are five nynphal stages 
which last a month or more, depending on tenperatures. Only one generation 
occurs each year. 

Spittlebugs have-piercing sucking mouthparts which they use to feed on 
plant juices. Feeding damage reduces plant vigor and can severely reduce 
strawberry yields. When spittlebugs overwinter in plant crowns, early season 
feeding can result in stunted, poorly-colored plants --da mage that looks very 
similar to that caused by cyclamen mites. 

Good weed control will help decrease damage by spittlebugs, as will 
maintaining weed-free hedgerows. 

Mites 



Two-spotted spider mites ( Tetranychus urt icae Koch) are tiny, light- 
colored mites that have two reddish to black spots on their bodies. These 
mites overwinter as adults and become active as tenperatures warm in the 
spring. If spring weather is warm and dry, mites build up rapidly due to their 
rapid rate of development. 

Spider mite feeding results in discolored or blotching of leaves, or under 
heavy infestations, bronzing and drying of the leaves. Since spider mites spin 
silken threads as they crawl around on leaf surfaces, in heavy infestations webs 
may form over entire plants. Eggs are laid on leaf surfaces or are attached to 
webbing. 

Severe mite damage not only affects infested leaves, it also decreases 
plant vigor and yields and can result in plant stunting and death. Early mite 
control is essential to maintain plant health and yields. Good weed control and 
attention to cultural practices may help with spider mite control. 

Root Weevils 



Over twenty species of root weevils are pests of strawberries. Of these 
the black vine weevil ( Otiorhynchus sulcatus F.) and the strawberry root weevil 
( O. ovatus L.) are the most irrportant. Although the adult weevils feed on 
foliage, the most important damage results from larval feeding on roots. Larvae 
are small, legless, white grub-like insects found in and around strawberry roots. 

Once strawberry root weevils have invaded a strawberry planting they are 
very difficult to control. Proper identification of the species is essential to 
adequate chemical control, where chemical controls can be used. Prevention 
and destruction of infected plantings are the best methods of dealing with 
strawberry root weevils. 

Root weevil populations increase as plantings are held over from year to 
year. Therefore, cropping for fewer years will help prevent problems. Good 
sanitation will also assist in preventing infestations. 



- 11 - 



White Grubs 

Like root weevils, white grubs, the larvae of Japanes ? beetles and other 
Phy llophaga species, can be severely damaging to strawb rry plants. White 
grubs are generally more troublesome on newly turned S( d land, or in very 
weedy fields. White grubs are C-shaped, about 1 1/2 inches long and have 6 
legs. They spend one or more years in the soil while completing their 
development. To prevent white grub infestations, do not plant strawberries in 
newly turned sod and keep fields weed free. White grubs are extremely 
difficult to control once they become established. 

For additional information on these and other strawberry insect pests and 
their control, refer to "Managing Diseases and Insects on Small Fruits" (MA 
CES C-164R. 1985. D. R. Cooley, J. L. Drozdowski, W. J. Manning, C. F. 
Brodel, and K. Haus<hild) or to the publications referenced below: 

Schaeffer, G. A. "Pest Management for Strawberry Insects." In: Handbook 
Series in Agriculture, Section D: Pest Management. CRC Press, Inc. 

Williams, R. N. (Mar-Apr.) 1979. Two Insect Pests Increase in Ohio 

Strawberry Fields. Ohio Report on Research and Development, pp. 24-26. 

« * * * * 



POLMOLOGICAL PARAGRAPH 

Market Basket Survey: 
Good News For Retailers And Consumers 

International Apple Institute 

A recent EPA-requested market basket study was conducted by Uniroyal, 
manufacturer of the Alar chemical, and the news is good for retailers and 
consumers. The study found that a random sanple of apples and apple products 
taken directly from supermarket produce aisles, farm markets, and apple 
orchards had levels of Alar far below the accepted legal level of 30 parts per 
million (ppm). Moreover, it was even below the four ppm estimated by the 
EPA. 

Market basket research found that most apples, which contained any trace 
of Alar, had an average of only 1.65 ppm. (That's roughly equivalent to one 
and a half cents in ten thousand dollars.) In fact, close to 25 percent of the 
apples tested had levels so low (0.1 ppm) they were not required for UDMH 
analysis. 

Consequently, because exposure to Alar is extraordinarily low, there is no 
perceptible risk to public health while additional tests are being completed. In 
addition, little or no spraying has been conducted due to apprehension about 

the issue. 

***** 



12 



MONITORING AND CONTROL OF APPLE BLOTCH LEAFMINER: 

AN UPDATE 

Thomas Green, Susan Butkewich, William Coli, 
Kathleen Leahy, and Ronald Prokopy 

Department of Entomology 
University of Massachusetts 

and 

Glenn Morin and Roberta Spitko 
New England Fruit Consultants 

In previous issues of Fruit Notes, we reported on the behavior of apple 
blotch leafminer (ABLM) moths [49(3):19-22] and on the use of red visual traps 
to monitor this pest [48(2):ll-14]. During the 1986 season, we conducted 
experiments to improve both monitoring and control of ABLM, in cooperation 
with a number of apple growers.^ 

During the 1985 and 1986 seasons, many growers successfully used visual 
traps hung horizontally in the tree canopy to determine the need for a pre- 
bloom insecticide application for ABLM. In 13 of 14 orchards, where the traps 
were used and no insecticide was applied for ARLM before bloom, the numbers 
of moths captured on the traps accurately predicted the need for an insecticide 
treatment. 

We have experienced two problems \i using this trap. First, in most 
cases, moth captures have been too few at tight cluster to make a treatment 
decision. Wh(>n using Thiodiin ^^ for ABLM control tnis decision must be rnade 
at tight cluster or earlier. Secondly, after a rail ABLM on the horizontal 
surface of the trap lose their distinctive wingscal? pattern, making it difficult 
to distinguish ABLM from other captured insects. 

To correct both of these problems, we experimented with a new trap 
position, tacking the trap vertically to the south side of tree trunks at knee 
height. Results from our study of ABLlVI behavior indicated that the motJis 
accumulate on the lower portion of the tree trunk during the day in early 
spring, probably for warmth. 

Our results this past season (Table 1) suggested that traps in this position 
captured more ABLM earlier in the spring than did traps in the canopy, 
although this difference was not statistically significant. ABLM were also more 
easily recognized on the traps in the new position, even after a rain. 



^The authors wish to express sincere appreciation to the following growers who 
participated in this work: Richard Bargeron, Keith Bohne, Dana Clark, Ed 
Roberts, and Mike and Tim Smith. Excellent technical assistance was provided 
by Suong Nguyen and James Mussoni. 



13 



Table 1. Number of ABLM moths captured on red visual traps in two positions 
at tight cluster and early pink, in seven commercial orchards. 



Trap position 



Mean ABLM captured per trap 
Tight cluster Early pink 



Horizontal in canopy 
Vertical in trunk 



l.l a* 
3.8 a 



9.3 a 
18.1 a 



*Means within a column not followed by the same letter are significantly 
different at the 5% level. 

Our results in 1986 suggest that if cumulative captures in this new 
position exceed 3-6 ABLM per trap by tight cluster or 18-22 by early pink, an 
insecticide treatment for ABLM may be desirable. This is a very rough 
approximation, based on results in only 7 blocks. We will continue testing in 
1987 to refine these estimates. In the meantime, wc liave continued confidence 
in the treatment threshold of 13 ABLM per trap by early pink for traps placed 
in the tree canopy. 

We also tested a spray tank additive, Nu -Fi lm-17 ' '" (6 oz./lOO gal.), with 
a single Thiodan^'^ (1 Ib./lOO gal.) treatment for ABLM at tight cluster. 
Growers using Thiodan for ABLM usually have found 2-3 pre-bloom applications 
to be necessary for good control. We hoped tliat Nu-Film-17, advertised as a 
spreader-sticker which extends the residual activity of insecticides, would hel[o 
to reduce the numbc of Thiodan applications needed. 

Our results did not bear this out, however (Table 2), Nu-Film-17 appeared 
to have no influence on the efficacy of Thiodan. It is noteworthy that both 
the single application of Thiodan and the Thiodan + Nu-Film-17 reduced ABLM 
mine densities, but not below our threshold of 0.13 first generation mines per 
leaf, supporting previous evidence that a single application of Thiodan pre- 
bloom usually is not sufficient to control ABLM. 

Table 2. Effectiveness of Thiodan^'" + Nu-Film-17'''", Thiodan ilone, and no 
treatment against ABLM. Applications were made at tight cluster in 
four commercial orchards. 



Treatment 



1st Generation 
mines per leaf 



Thiodan 

Thiodan + Nu-Film-17 

Untreated 



0.13 a* 
0.14 a 
0.26 b 



*Means within a colunn not followed by the same letter are significantly 
different at the 5% level. 



- 14 



VVc also tested a new material, Dimilin^'" for control of ABLM, Dimilin is 
a chitin syntht sis inhibitor which acts against both ABLM adults and eggs. 
Dimilin has lonj; residual activity and is reported to be non-toxic to beneficial 
predators, reducing the risk of mite and aphid build-up associated with the use 
of synthetic pyrethroids [see Fruit Notes 51(2):6-8]. A single application of 
Dimilin (4 oz./lOO gal.) was very effective in controlling ABLM when applied at 
tight cluster (Table 3), as was Vydate"*" (1.5 pt./lOO gal.) applied at early pink. 
ABLM mine densities in the treated trees remained well below treatment 
thresholds through the second generation. 

Table 3. Influence of pre-bloom application of Dimilin'"^ and Vydate "^ on 
ABLM densities in three commercial orchards. 



1st Generation 2nd Generation 

Treatment mines per leaf mines per leaf 



Dimilin at TC 0.04 a* 0.08 a 

Vydate at EPK 0.02 a 0. i? b 

Untreated 0.26 b 0.60 c 



*Means within a column not followed by the same better are significantly 
different at the 5% level. 

We also tested Dimilin for control of 2"*^ generation ABLM (Table 4), 
applying a single treatment at 2"fl cover in one orchard, ard two treatments (at 
2nd oover and 19 days later) in another orchard. Our results showed significant 
reductions in ABLM larval densities in treated trees in both orchards. 

Table 4. Influence of a single application of Dimilin (Block 1) at 2nd cover 
(2C) and two applications of Dimilin (Block 2), one at 2nd cover and the 
second 19 days later, on ABLM densities. 



2nd Generation 
Treatment mines per leaf 



Block 1: Dimilin at 2C 

Untreated 0.81 b 

Block 2: Dimilin at 2C + 

19 days later 0.05 a 

Untreated 0.60 b 



*Means within a column not followed by the same letter are significantly 
different at the 5% level. 

Our results with Dimilin agree vvith results from other states and Europe. 
Hopefully, Dimilin will be available for use in the near future. 



- 15 - 

In conclusion, the visual monitoring- trap for ABLM has been used 
successfully to determine the need for an insecticide application before bloom in 
many orchards. A new position for this trap may improve its usefulness by 
allowing an earlier treatment decision and reducing confusion in the 
identification of the insects captured. Dimilin holds promise as a new selective 
treatment option for ABLM without threatening biological control of mites and 
aphids. 

The ABLM has become an important pest in our region by having 
developed resistance to organophosphate (OP) insecticides commonly used in 
commercial orchards. Beneficial parasites which control ABLM very effectively 
in unsprayed trees are killed by these OP's and other insecticides. Whatever 
we can do to reduce insecticide use in our orchards, through the use of IPM 
sampling techniques lor example, will help to spare these beneficials and allow 
them to assist us in controlling ABLM. 

* « * « * 



POMOLOGICAL PARAGRAPH 

State of Maine Suspends Action 
on Mandatory Tolerances for Alar 

International Apple Institute 

Robert Deis, Director, Maine Bureau of Public Service, in an October 10, 
1986, memorandum to food processors said that because "many food processors 
have voluntarily decided to discontinue their use of Damino/-ide-treated raw 
products and many farmers, part iculirly apple growers, have substantially 
reduced their applications of Daminozide--we expect this will lead to a 
significant reduction in public exposure--we are therefore suspending 
implementation of mandatory state tolerances in hopes that the-y will be 
unnecessary. " 

The residue guidelines considered in Maine (and the basis for acceptable 
voluntary action) are 1 ppm for infant and baby food and 5 ppm for general- 
use, heated, processed food packaged before 10-1-86 and non-detectable and 1 
ppm, respectively, thereafter. 

Rather than setting mandatory tolerances, it was pointed out the state was 
taking non-regulatory steps which include a survey of processors to clarify the 
extent and nature of their Daminozide policies and to monitor residues of 
Daminozide/UDMH in products sold in Maine. The memoriindum to processors 
indicated that if product is found to have residues above what the state 
considers acceptable levels, voluntary withdrawal of lots will be requested. 



Reprinted from Apple News 17(5):l-2. 



16 



RBDUCIN*; ENERGY COSTS IN CA STORAGE 

J. A. Bartsch 

Cornell University 

Agricultural Engineer 

Dedication 

This work is dedicated to Professor Robert M. Smock, who in 1938 
published the results of his research on evaporator fan cycling to save energy. 
We are grateful for his constant support and encouragement in this project and 
in all fruit storage programs. Dr. Smock suffered a fatal heart attack on April 
22, 1986 as he walked across the Cornell campus to his office in the Pomology 
Department. 

Introduct ion 

The concept of reducing cold storage energy use through evaporator fan 
cycling is not new. In 1938 R. M. Smock (2), a Pomologist at Cornell 
University, wrote of his work, "Certainly no differences were indicated in this 
study which would justify the extra power cost of continuous blower operation." 
Smock's study indicated that fan operating time could be reduced by 45% with 
no detrimental effect on fruit quality and condition. Thirty plus years have 
elapsed, and now the merits of this original research are being discovered and 
applied to modern CA storage in New York. 

Storage Technology 

Fruit storage technology has changed tremendously since the first cold 
storages were built in New York State. The handling, cooling, and storage 
milestones are highlighted in Table 1. 

Table 1. Commercial loading and cooling rates for apples. 



Year 



Loading 
Period 



Cool ing 
Time 



Room 
Atmosphere 



Handling 
Method 



1924 
1938 
1945 
1965 
1986 



2-3 weeks 
2 weeks 
1 week 
1 week 
5 days 



1 week 

1 week 
3-4 days 
2-3 days 
"overnight" 



Air 
Air 
CA 
CA 
"Rapid" 



CA 



Barrels 

Bu. Box 

Bu. Box 

20 Bu. Bin 

20 Bu. Bin 



The industry began to use on-farm refrigeration for apples stored in 
barrels around 1924. Professor Smock's study involved refrigerated air storage 
of apples in bushel boxes in 1938. Around 1945, commercial CA storage was 
begun, and by 1965, the importance of faster cooling was recognized and 20- 
bushel pallet bins were in widespread use. Currently, commercial operations are 
striving for overnight cooling and rapid CA. 



17- 



The technology change has required increased cooling capacity for pull 
down, which Is reflected In larger evaporators and bigger air handling systems. 
The very first refrigerated rooms relied upon gravity refrigeration and contained 
no supplemental air circulating equipment. By 1938, forced air blower units 
delivered 18 air changes per hour and added approximately 198 watts of heat 
per 1,000 bushels of stored fruit. Current centrifugal blower units have a 28 
air-change -per-hour capacity. Direct throw propeller fans on modern 
evaporators deliver 90 air changes per hour. The present hardware associated 
with both types of systems adds approximately 375 watts of heat per 1,000 
bushels of fruit. The heat added by the fan motors is now 2 to 3 times greater 
than the heat of respiration of the fruit (130-180 W/1,000 bushels). 

The energy budget for a modern New York State CA storage is shown in 
Figure 1. These data are for a 120,000 bushel plant equipped with flooded 
ammonia refrigeration. The daily electrical requirements for cortpressors and 
evaporator fans are shown along with the total for the refrigeration system. 



2500 



2000 - 



1500 



1000 



500 - 




• 40 Hp Conprcssor 




'^''^^l^p^hiA,^^'^ 



7S Hp Compressor 



'"' '^A'^^A^ 



OCT 



NOV 



occ 



JAN 



rcB 



APR 



MAT 



Fig. 1. Daily energy consumptions in a 120,000 bushel CA storage, where fans 
were operated continuously. 



The "measured total" includes the relatively small amount of electricity used by 
water pumps and condenser fans--a quantity which averages approximately 6% of 
compressor use. The "metered total" is the daily average electrical use 
calculated from monthly power company bills. Hot water heating, office space 
heat, and the electricity used by CA burners and scrubbers are included in the 
"metered total." 



18 



The data in Table 2 indicate that a total energy savings of 40% is possible 
if evaporator fans could be turned off half of the time. Total savings approach 
60% when fans ire off 16 hours out of 24 hours. Based on early research by 
Smock and later reports by Yost (5) half-time reduction in fan operation is 
feasible and causes no detrimental effects on stored fruit quality or condition. 

Table 2. Daily energy use and potential energy savings through fan cycling 
in 120,000 bushel CA storage 



Item 




on 


Fans 
cont inuously 


Fans cycle 
5 096 on, 5 0% 


id 
off 


Fa 

25% 


ns cycled 
on, 75% off 


Fans 

Coripressor 

Condenser 




- 


750 kWh 

500 kWh 

30 kWh 




375 WVh 

375 kWh 

23 kWh 






188 kWh 

313 kWh 

19 kWh 


Total use 
% Savings 


1280 kWh 
0% 




773 kWh 
40% 






5 20 kWh 

59% 


Air Handler 


Eff 


iciency 













During storage trials (1), we investigated the efficiency of high velocity 
direct throw air handlers presently used in CA storages. (Efficiency is defined 
as the quantity of air returning through pallet runner openings conpared with 
the total quantity of air delivered from the evaporator discharge). When 
efficiency measurements were made in a 30,000 bushel CA room, 70% of the 
discharge air never passed through the stacks; it simply short-circuited over the 
top of the bins and back to the evaporator. When air flow was reduced 50% by 
turning off half the fans, the return air flow decri;ased only 22%. Since the 
measured return flow coming out of the stacks was still uniform over the entire 
room, we concluded that half of the evaporator fans could be safely shut down 
after field heat was removed and the CA room was sealed. 

Control Strategies 

The energy crisis of the 1970s prompted eastern growers to begin using 
evaporator fan cycling to save energy. The first storage operators to employ 
fan cycling simply turned their refrigeration systems off at night and back on 
again in the morning during the winter. Research studies (2,4) indicated that 
tennperature variations on the order of +^ 1**F from the set point would be 
expected when systems were turned off for 12 to 14 hours. We found these 
variations to ho, greater than those experienced when refrigeration systems 
operated continuously. Since fruit quality and condition after CA storage in the 
cycled rooms was equivalent to that in rooms operated continuously, the cycling 
practice became widely accepted. 



19 - 



Our fruit storage industry currently enploys several control strategies for 
fan cycling. Manual control is still used by some of the smaller growers. Time 
clock control is used, and a few new systems employ programmable load 
controllers to sequence fan and refrigeration operations. Presently, however, 
the most popular technique is to cycle fans and refrigeration with a solid-state 
thermostat. This thermostat, accurate to +^ 0.25OF, can be set to control only 
temperature while fans run continuously during loading and pull down. Later 
the thermostat is switched to control fans and refrigeration together. Remote 
temperature sensors are installed in the CA rooms where the thermostat is used 
to control fan cycling. 

Initially we were skeptical of using a single thermostat sensor to control 
all of the fans in the CA room. Our recommendation still calls for remote 
tenperature sensors in all rooms whether fans are cycled or not. We encourage 
growers to turn at least some of the fans on for 30 minutes each 12 hours 
during very cold weather. We have recorded fan cycles of up to 36 hours off 
and 1 hour on when the thermostat alone was used to cycle the fans with the 
refrigeration. 

After 3 years of experience we are not aware of any fruit condition 
problems resulting from the fan cycling methods described above. Some 
freezing damage has occurred in open, partially enpty CA rooms, because 
insufficient respiration heat was available. Our biggest concern is that 
compressor capacity in older plants now far exceeds the load developed in the 
CA rooms when fans are cycled. During extended cold periods, machines may 
sit idle for 24 hours or more, and provisions must be made to keep the 
conpressor room warm. Heat reclaim from these compressors is no longer 
possible during the storage season when the fans are cycled. 

Temperature, Relative Humidity, and Atmosphere Variations Due to Fan Cycling 

We find that the tenperature controller, not the fan cycling practice, is 
the cause of major temperature variations in the CA rooms. We have 
documented temperature variations in excess of + 20F in rooms with 
continuously operated fans controlled by mechanical thermostats. Tenperature 
variations in cycled rooms controlled by the solid state thermostats average + 
1° or less. 

Few data exist for relative humidity variations. Some very limited data 
from new storage facilities indicate cycled rooms yield less defrost water than 
identical continuously operated rooms. In theory, this should be the case, but 
we do not have sufficient data to confirm it for commercial systems. 

We are equally short of data on atmosphere concentration variations. In 
one study of 1% oxygen storage in a 30,000 bushel CA room, no variation in O2 
levels could be detected after the fans were off for 12 hours. This 
determination was made by inserting sanpling lines into 6 stack locations during 
loading and monitoring the oxygen level with an electronic analyz.er. 



20 







SI r 



mc 



Fig. 2. Monthly energy use in a 300,000 bushel CA storage. 



83-Ha 
8S-fl6 




Fig. 3. Monthly energy use In a 175,000 bushel CA storage. 



21 - 



Energy Savings 

Eastern storage operators are sold on fan cycling to save energy and 
dollars. We have documented the monthly savings by two of our commercial 
cooperators and present these data in Figures 2 and 3. The "base year" is the 
1982-83 storage season, when no fan cycling was used. Conversion to fan 
cycling was conpleted in 1984-85; total energy use was reduced nearly 50% in 
the process. The need for good storage management with fan cycling is 
indicated in Figure 3, where higher than expected use occurred in 1985-86. 
This was due to a tenporary change in refrigeration plant management from 
October through February in this storage. The new manager was not 
"comfortable" with fan cycling practices of the previous year and operated the 
evaporator fans for a longer period of time each day during that season. 

The fan cycling practice holds great promise for energy cost savings. 
Energy rates in the Northeast currently average 11 cents per kWh and electric 
costs are a significant part of the total storage budget. Our research has 
shown that fan cycling results in a 60% savings in energy in commercial CA 
storages. The simple payback on the fan cycling thermostat controller and 
remote temperature sensing equipment is currently 4 to 5 months. The value of 
energy saved is equivalent to 16 cents per bushel of storage capacity. We 
estimate that the potential value of energy savings due to fan cycling is 1 
million dollars annually for our CA industry in New York State. 

Literature Cited 

1. Bartsch, James A. 1982, Consunption and loss of energy in commercial 

units. Proceedings of 3^"^ National CA Conference. Timber Press. 
Beaverton, Oregon. 

2. Blanpied, G. David. 1979. Effect of blower operation upon temperatures in 

CA rooms. Unpublished data. 

3. Smock, Robert M., and S. R. Shapley. 1938. Blower operation in farm cold 

storage. Refrigeration Engineering Vol. 36. 

4. Yost, G. E. 1980. Tennperature data from CA rooms operated with 
intermittent fan cycles. Unpublished data. 

5. Yost, G. E. 1984. Energy saving through the use of fan and refrigeration 

cycling in apple cold storage. Transactions of the ASAE:497-501. 

* * * « * 



22 



AN ECONOMIC ANALYSIS OF ORCHARD REJUVENATION 

IN RESPONSE TO THE REDUCTION OR THE 

ELIMINATION OP THE USE OF ALAR*^") ^ 

Martha Kimball and Wesley R. Autio 

Department of Plant and Soil Sciences 

University of Massachusetts 

Since about 1966, Alar''" has been used to extend the harvest season 
for Mcintosh apples by controlling preharvest drop and delaying fruit ripening, 
enabling growers to efficiently manage harvest labor and cooling capacity. 
Without Alar*"', the number of harvest weeks for long-term storage is 
decreased, thus increasing the quantity of fruit that must be harvested per day. 
To accommodate this higher harvest rate, picking labor and cooling capacity 
must be increased, raising production costs. Alternative methods of extending 
the harvest season would help alleviate this critical problem. 

This study examines the economics of replacing 50 acres of mature, 
seedling-rooted trees (that are difficult to pick and lack good color 
development) with dwarf and S(imi -dwarf trees that are more efficient to pick, 
color well, and allow extension of the Mcintosh harvest. It is assumed that the 
grower must replace this block over a 10-year period, rather than all at once, 
so that income can continue to be generated each year. The objective of the 
study >vas to determine the mix of different Mcintosh strains and rootstocks 
that would best use farm resources under Massachusetts production and 
marketing conditions during this orchard replacement. 

The study was conducted using a multiperiod linear programming model 
that was developed specifically for Massachusetts apple growers to aid in long- 
range ()lanning of cultivar selection. That model looked at replacing standard 
Mcintosh acreages with 7 different cultivars. However, given the commercial 
importance of Mcintosh in Massachusetts, we have chose to replant only with 
McIntosh--but to use a mix of Mcintosh strains on semi -dwarf ing and dwarfing 
rootstocks that will spread the harvest season, best use available resources, and 
maximi/.e prof itablility of the orcliarl. 

We tried to achieve goals by selei^ting strains and rootstocks with specific 
properties. Our goals and choices .vere: I) To produce trees smaller than 
standard tliat will produce fruit witii hotter color and ripen earlier (Marshall 
Mcintosh on M.7/V); 2) To produce trei^s sn^iller than standard but with fruit 
ripening the same time as standard (Rogers Mcintosh on M.7A); 3) To produce 
much smaller trees capable of producing fruit for rapid, early harvest (Marshall 
Mcintosh on M.26); 4) To produr^e highly colored fruit ripening later than 
standard (Marshall McI itosh on 0A.R1). Please note: OARl is an experimental 
rootstock that !ias been found to delay ripening of Golden Delicious in Oregon 
by about 10 days. 



^This study was supported by a grant from the Massachusetts Fruit 
Growers' Association 

^Hanlon, W. L., C. E. Willis, and R. L. Christensen. 1976. \ framework 
for long range apple variety decisions. Mass. Agrio. Exp. Sta. Bull. 621. 



- 23 



Four management limitations (constraints) were inserted into the model, 
namely, cooling capacity, harvest labor, storage capacity, and replanting 
acreage. These are described briefly. 

\creage: The planting period for the 50-acre rejuvenated orchard was 10 
years. Each year 5 acres were removed and replanted. The model also used a 
20-year period--10 years beyond the end of replant ing--to evaluate consequences 
of strain/rootstock selections up to the time the orchard readies full produc- 
tion. For eaiih planting year, the model decided how many acres of each 
strain/rootstock combination to plant for maximum prof itabli lity, given the 
following set of conditions. 

Storage. Most orchards divide the marketing of their crop between the 
fresh market, during and immediately following harvest, and long term storage. 
However, to simplify the model, we assumed that all fruit produced on the 50 
acres was placed in long-term storage. 

The storage capacity was set initially at 20,000 bushels. It was increased 
to 48,500 bushels in year 20 .vh(>n most ,)lantings had reached lull tnat irity. All 
trees less than 4 years old were considered nonbearing mid u-ed none <jf the 
storage capacity. Trees older than 4 years were bearing .ind thMr yield used a 
portion of the total storage capacity. 

Harvest labor. The harvest season was divided into eifrht 3-day picking 
periods. These extended from September 4 to October 1. A percentage of the 
total yield for each strain-rootstock combination was harvested during at least 
4 of these picking periods. Each combination had harvest labor needs specific 
to its stage of growtJi because yield varies with strain, rootstock, and age of 
tree. The available labor hours for eacii harvest period were deterrnined by 
multiplying the number of pickers (set initially at 7) by ivorking hours per day 
(set constant at 9) and by 3 days per Iiarvest period. For the 50 acres, 189 
hours were available for each 3-day period. 

Each strain-rootstock (^^mbiiat ion contributed to the use of harvest labor 
depending on the yield, the tree's ag<!, the percentage of yield harvested during 
a particular i)icking period, and the picking rate. In year 20, when most 
plantings were matare, additiotial harvest labor vvas required. To enable the 
model to operate, harvest labor was increased to 550 hours per picking period 
(20 pickers) by year 20. 

Cooling capacity. Field heat must be removed from th<i apples after 
harvest. The (juantity of fruit that can be (tooled is limited by the size of the 
refrigerating equip-nent. Cooling lapac^ity was evaluated to correspond with the 
eight 3-day harvest periods. The total capacity was 9,000 bushels for 3 days or 
3000 bushels per day. 

Each strain-rootstock comoiiat ion contribut:!S to the orchard's returns to 
management. This contribution dei)<;nds on the difference between revenues and 
costs. In this study, returns to management covered overhead costs, 
managernent labor, an<l profit. 

Revenues were dependent on yic^Id, which varies accorcli ig to the trecs's 
age, the strain-rootstock combiiation, and the (jrice. Price was held constant 
for all years but varied with fruit gra<le. ^'or all trees, yield was assorted as 
follows: 75% extra fancy, 15% utility, and 10)6 processing. The busiiel prices 



- 24 - 



were $10.00, $5.00, and $2.30, respectively. Obviously, dramatic differences 
exist between the newly planted trees and the standard trees as to the 
distribution of fruit into grades, but to simplify the model the proportions were 
held constant and the differences were accounted for with yield differences. 

Total cost for each strain-rootstock combination was the summation of the 
following costs: site preparation, planting, nonbearing growing years 1 through 
3, bearing growing years 4 through 20, harvesting, cooling, and storage. All 
costs were figured on a per acre basis using current prices. 

For the 20-year life span of the rejuvenated orchard, costs and revenues 
were totaled and returns to management were calculated per acre for all strain- 
rootstock combinations. An acre planted in year 1 incurred costs of site 
preparation, planting, and nonbearing maintenance through the first 4 growing 
years with no revenues received. In year 5, when these trees began to bear 
fruit, revenues were positive and increased through matarity. Revenues were 
received from these trees for 16 years. However, an acre planted in year 5 
earned revenut^s for only 12 of the 20 years. Trees planted in year 10 earned 
revenues for only 7 years within the framework of this study. 

RESULTS 

The discussion of results is divided between findings of the original set of 
constraints, called the original modiil, and findings of the modified models 
resulting when constraints .vere changed to reflect changes in availability of 
orchard resources. Comments are included about each strain-rootstock 
combination and about ?ach constraint. 

Results of the Original Model 

Table 1 presents the optimal lO-year plant ing plan for the 50 rejuvenated 
acres, as determined by the original model. 



Table 1. Planting plan for the original model. 



Planting year Rogers/M.7A Marshall/M.7A Marshall/M.26 Marshall/OARl 



10 5 

2 2.2 2.8 

3 5 

4 3.9 1.1 

5 5 

6 0,1 4.9 

7 5 

8 5 

9 5 
10 5 

TOTAL 0,1 36 13.9 



25 



Mar3hall/M.26. Marshall on M.26 was favored. The model suggested 
planting 36 of the total 50 acres with Mar3hall/M.26. The early coloring strain 
and the more open tree in this combination gives the earliest and longest 
harvest season of the trees compared. Also, because of its precocity, 
Marsha 11/M. 26 reaches full production earlier than other strain-rootstock 
combinations. Therefore, this combination has less conpetition for labor ind 
cooling capacity, and are the primary factors leading to its selection for the 
most planting. 

Marsha 1 l/OAR 1. The combliation of Marshall on 0AR1 composed 
practically all the remainder of the 50 acres. This strain-rootstock combination 
should yield later in the season, extending the harvest at least 3 days beyond 
other combinations. A disadvantage is that full production is not reached until 
approximately 3 years after Marshall/M.26. Also, it is less precocious and 
begins bearing later than other combinations. Hence, its contribution to returns 
to management was delayed. The model decided to plant 5 acres in year 10 
because maximum yield would not be reached by year 20, so less burden was 
placed on storage capacity. OARl is, at this time, purely experimentnl, and we 
do not know how it will perform with a Mcintosh scion and under 
Massachusetts conditions. However, it is obvious that a strain-rootstock 
combiiation which ripens later than norrnal i:an be advantageous because of its 
ability to expand the harvest season and reduce comijctition for labor ind 
cooling. 

Rogors/M.7A. The model suggested planting only 0.1 acre of Rogers/?4.7A. 
Rogers and seedling Mcintosh are harvested over a similar time period. 
Replacing seedling trees with Rogers on M.7A did not expand the harvest 
season; thus, that action does not alleviate any pressures caused by the nonuse 
of Alar''". However, some benefits may be gained with a smaller tree, such as 
less picking time per bushel. 

Marshall/M. 7A. No acreage was suggested for planting Marshall/M. 7A 
given the conditions of the original model. This strain-rootstock combination 
competes with MarshaU/M.26 for resources during the sane periods. Marshall/ 
M.7A's have a somewhat shorter harvest season than Marshall/M. 2fi, and a 
higher percentage of tne crop is picked during the first week. Also, 
Marshall/M. 7A reaches full production 1 year later than Marshall/M.26, so it 
offered no financial advantage. 

Some alterations were made in constraints to allow the model to operate. 
First, to not violate the assumj^tion that all fruit must be stored, storage 
capacity was increased frorn 20,000 busliels to 48,500 by year 20. Also, in year 
20, cooling capacity was increased from 9,000 bushels to 0,800 to harvest 
periods 4 through 8, which were the most prolific harvest periods. This change 
resulted in cooling capacity becoming most constraining in period 3. Harvest 
labor was set initially at 189 ho.irs jjcr 3-Jay harvest period. Thu .vas in<;rensed 
to 550 hours by year 20 as trees reached full maturity. The 189 hours became 
constraining in year 11 during the 4^^^ and 5t'i harvest periods. If labor was 
reduced in the S^fi period, then Rogers/M.7A would not be planted. If the 
amount of labor increased then the <]uantity of Marshall/OARl selected for 
planting declined. 



26 - 



Results of Modified Models 

After results of the original model were obtained, the magnitudes of the 
constraints, or resources available, were (^hanged for labor, cooling capacity, 
and storage. The following is a description of the overall changes made to the 
constraints and of the responses to those changes. For a more detailed 
discussion of the modified models, readers should refer to the Extension 
publication we have written (to be published in January, 1987) that describes 
this research at greater length. 

Increasing the amount of harvest labor, cooling capacity, or both 
simultaneously caused greater changes in the planting mix than changes in 
storage capacity. Therefore, storage capacity was increased to handle all apples 
and then held kept constant. Harvest labor md cooling capacity were increased 
only in the most ;onstraining 3-day harvest periods in any year, as opposed to 
being increased in all harvest periods for any year. This enabled the 
identification of the harvest periods that demanded the greatest amount of labor 
and cooling (Capacity. Also, this treatment made it easier to note how the 
selection of different combinations was influenced by changes in harvest labor 
and cooling capacity. Cooling capacity was most constraining in year 20, when 
plantings ivere nature and produced Jtiaxi nurn yields. In this year for harvest 
periods 4 through 8, cooling was increased in steps from the initial 9,000 
bushels per 3 days to 10,000, and finally to 11,000 bushels per 3-day harvest 
period. 

Harvest labor was altered in year 11 for the 2T' through the 4^^ periods 
(September 7 to 17). The number of pickers was increased in steps from 7 to 8 
to 9 in year 11. With each picker working 27 hours in a 3-day harvest period, 
the total hours available for each harvest period increased from 189, to 216, 
and to 243. In year 20 harvest labor was most constraining during the 4*^" and 
5^'^ harvest periods (September 14 to 17 and 1'^ to 21), so labor hours available 
were raised to 5G7 per 3 days (21 pickers) for both periods. 

Marsha I l/M. 26 . Marshall on M.26 was selected for planting most frequently 
in all models. Overall, this strain-rootstock combination makes the best use of 
resources as explained previously. However, the advantages do not inply that 
Marshall/M.26 should be the sole strain planted on the rejuvenated acreage. 
Such action would result in high labor ind <.ooling requirements concentrated 
during the days of Marshall/M. 26's peak picking period. Again, the objective 
vvas to determine the most profitable nix of strain-rootstock combinations that 
would use the inputs available efficiently. 

If ample harvest labor vas available at matirity of the orchard, 
Marshall/M.26 replaced acreages selected originally for planting with 
Marshall/OAR I. In the original model, no Marsiia ll/M.26 was chosen in planting 
year 3. However, 2.5 acres were chosen when harvest labor and total cooling 
capacity increased. For planting year 9, the original model decided to plant all 
5 acres with Marshall/M.26. However, as harvest labor ind cooling became lass 
constraining, less of this combiiation was chosen, with no Marshall/M.26 being 
selected for year 10. Probably, this situation arose because labor and cooling 
capacity were not increased to high enough levels. 



- 27 - 

Rogers/M. 7A. In the original model Rogers/M.7A was selected only in year 
6 for 0.1 acres. When the number of pickers increased to 9 in year 11 for 
harvest periods 3 and 4, 1.5 acres of Rogers/M. 7A was selected for planting in 
year 1. However, if the number of pickers was greater than for the same 
harvest period, planting Marshall/M.26 was more profitable. Acreage of 
Rogers/M. 7A planted during year 3 increased when harvest labor increased 
during year 20. 

Also, selection of Rogers/M. 7A was sensitive to cooling capacity. 
Increasing cooling to 11,000 bu per 3-day period during year 20 stimulated 
approximately 3 acres of Rogers/M. 7A to be planted in year 8. This resulted in 
a reducition of Marshall/M.26 acreage from !J acres to about 2 acres in year 8. 
Rogers/M. 7A replaced 1.4 acres of Marsiiall/M.26 in year 9 for the same reason. 

Hogers/M. 7A's picking schedule is more similar to Marshal l/OARl than to 
Marshall/M.26. The bulk of the crops is harvested during the same 2 weeks, 
but harvestinjf of Marshall/OARl extends about one half week past that of 
Rogers/M. 7A. However, as more labor and cooling capacity become available 
Rogers/M. 7A acreage increases while that of Marshall/OARl df'creases, because 
Rogers/M. 7A begins bearing earlier and reaches full production sooner. 

Marshall/M.7A. Because of earlier coloring Marshall/M.7A has a longer 
potential harvest period than Rogers/M.7A. However, its harvest period 
coincides with that of Marshall/M.26, but the latter has a more efficient use of 
harvest labor. Therefore, in most cases, Marshall/M.26 was chosen rather than 
Marshall/M. 7A. In fact, Marshall/M.7A never was selected until the 10th 
planting year. 

Marshall/OARl. OARl is attractive because; it may delay fruit ripening. 
Extending the harvest season places demands on resources at times when other 
strains place less or no demand on harvest labor md cooling capacity. It is 
the one strain requiring harvesting in period 8, and it co(ni>etes only with 
Rogers/M. 7A during period 7. In all rnodels, somi- .b^reage of Marshall/OARl 
was selected for planting, because it comple nents other strains as an aid in 
expanding harvest from 2 vveeks to 4 w;.'cks and provides more efficient use of 
labor and cooling capacity. 

CONCLUSIONS 

It should be remenberid tliat the results of this study were specific to tiie 
50-acre rejuvenated orchard described by a given set of conditions. Five acres 
of the orchard was replanted yearly for 10 years. The research used the 
methodology of multi-period linear programming to determine the number of 
acres of 4 different Mcintosh strain-i-ootstock combiiations that should 
comprise the replanted acres each year. The objective of planting a mix that 
generates the greatest profit over the 20 year period was (^rjustraincd by the 
amount of storage, labor, and cooling capacity available during harvest. 

Given the limits, Marshall on M.26 composed 66 to 72% of the 50 acres 
replanted in each of the alternative >nodels which used varying levels of harvest 
labor ind cooling capacity. Marshall/M.26 requires more labor and mat trials at 
planting time becau-;c; the trees may requin; staking and may require more 



- 28 



intensive in.'inageinent during the entire life of the tree. However, several 
characteristics contribute to the selection of these trees as the best economic 
choice: the trees reach full production earlier, the harvest period is longer, 
and fruit can be harvested at a faster rate than those of other strains. 

OARl is an experimental rootstock that is being field tested with Mcintosh 
in Massachusetts. It was ised in this study to determine its economic potential. 
Marshall on OARl was selected by the model when harvest labor and cooling 
capacity ^fere most constraining. Due to the experimental nature of this 
rootstock Marshall/OAR 1 is not suggested for planting, but these results show 
that a combination of strain and rootstock which results in later ripening is 
desirable and can have high economic potential. Recent results suggest that 
Mark also may delay fruit ripening and may be able to provide benefits similar 
to those projected here for OARl. Unfortunately, it also is experimental, but 
lias undergone moie thorough testing tlian OARl at this time. Clearly, a 
rootstock that delays Mcintosh harvest has great value in a strain-rootstock 
mix. 

Acres selected for replanting with Rogt^rs on "1.7A increased when harvest 
labor and cooling capacity ivere more :ivailable. At the least constraining levels 
of resources in the later planting years, Rogers/M.7A substituted for 
Marshall/OARl. Thus, availability of labor and of cooling capacity affect 
decision-making in this rejuvenation framework. 

Lastly, Marsiiall on M.7A was selected minimally. This study did not 
recommi'iiil planting MarshaU/M.7A when Marshall/M.26 is an alternative. 
However, >vhen M.26 is not an alternativf; because of inadequate soil moisture, 
too shallow a soil, or a desire to avoid the more intensive management 
required, Marshall/M. 7A would bo the obvious replacement. 

Every orchard functions under different conditions; yet, similarities among 
orchards in growing and harvesting practices exist. This study examined a 
hypothetical orchard. It did not use the costs of any specific orchard. 
Alt'iough the results are specific to the rejuvenated 50 acres in the model, 
suggestions for replant ing schemes can be rnade. To guarantee that all fruit be 
harvested in all cases, harvest labor must be increased to 9 pickers for the 50 
acres in year 11 and to 21 pickers by year 20. If this is not done, the entire 
crop at full maturity cannot be picked. Also, cooling capacity must be 
increased from the original ability to cool 9,000 busliels per 3-day picking 
period, to 11,000 bushels per period by year 20. 

Table 2 is a suggested 10-year planting mi >c for a rejuventated 50-acre 
orchard. It is based upon the research results and should be used as an aid for 
grower decisions. Again, because MarsIiaU/OAR I is experimental, it is not 
included in the suggest ed plant ing mix. For rejuvenatid acreages of differing 
sizes, the percentage values can be applied. For exatrple, in year 3, 60% of a 
rejuvenated acreage would be planted with Rogers/M.7A, and 40% planted with 
Marshall/M.26. 



- 29 



Table 2. Suggested planting mix in a 50-acre rejuvenated Mcintosh orchard. 





Rogei 


rs/M.TA 


Mi 


ir3hall/M.7A 

% of 


Mars! 


mll/M.26 






% of 


% of 


Year 


Acres 


Planting 


Acres 


Planting 


Acres 


Planting 


1 
















5 


100 


2 
















5 


100 


3 


3 


60 










2 


40 


4 
















5 


100 


5 
















5 


100 


6 
















5 


100 


7 
















5 


100 


8 


2.5 


50 










2.5 


50 


9 


3.5 


70 










1.5 


30 


10 


5 


LOO 







a 









TOTAL 



14 



36 



% of total acreage: 

2H% 



72% 



The authors would like to thank the Massachusotts Fruit Growers' 
Association for generously supporting this study. 



COOPERATIVf EXTENSION SERVICE 

U S DEPARTMENT OF AGRICULTURE 

UNIVERSITY OF MASSACHUSETTS 
AMHERST MASS 01003 



OFFICIAL BUSINESS 

PENAl TY FOR PRIVATF USE S3()0 



BULK RATE 


POSTAGE 8. FEES PAID 


USDA 


PERMIT Nu G:r>8 



r 



Fruit Notes 

Prepared by: Department of Plant and Soil Sciences 

Massachusetts Cooperative Extension, University of Massachusetts, United 
States Department of Agriculture and Massachusetts counties cooperating. 



Editors: W. R. Autio and W. J. Bramlage 




Volume 52, No.2 
SPRING ISSUE, 1987 



Table of Contents 



Soil Applications of Gypsum Can Improve 
Apple Fruit Calcium Levels 

Pomological Paragraph: 
Reducing Fruit Load on Tree Leaders 

Can Rootstock Affect Apple Ripening and Quality? 

Pomological Paragraph: . 
Pruning Well-feathered Trees at Planting 

A Report on the 1986 Massachusetts 
Apple IPM Program 

Pomological Paragraph: 
Early, Heavy Cropping of Apples 

Results of 1986 Chemical Thinning Trials on Mcintosh 

Timing the Tarnished Plant Bug: A Tale of Frustration 



SOIL APPLICATIONS OF GYPSDM CAN IMPROVE 
APPLE FROIT CALCIOM LEVELS 

William J. Bramlage 

Department of Plant and Soil Sciences 

University of Massachusetts 

Calcium (Ca) deficiency in the fruit is a chronic problem in modern apple 
production. If this deficiency occurs, it causes poorer keeping quality of the 
fruit . 

There are 4 possible approaches available for dealing with potential Ca 
deficiency in apples. These are cultural practices, soil treatments, foliar 
sprays, and postharvest dips or drenches. These approaches were addressed 
recently (Proc., Mass. Fruit Growers' Assn. 93: in press). 

Of these approaches, soil treatments are generally the least effective due 
to the poor ability of apple roots to absorb Ca from the soil solution. We 
have tried numerous treatments and have obtained marginal benefits at best. 
However, recent results from applications of gypsum (CaS04-2H20) have been 
better than any from earlier studies of soil treatments and will be described 
here . 

We have conducted 2 major trials with gypsum. The first trial was 
initiated by Dr. Mack Drake in 1976 in a block of mature, seedling-rooted 
Cortland trees. Half of these trees received 80 lbs. of gypsum spread under 
the canopy in April and half received no gypsum. Otherwise, the trees were 
fertilized and cared for in an identical manner. These applications were 
repeated annually through 1986. 

During this period leaves and fruit were sampled and analyzed for mineral 
concentrations, and fruit were usually stored in both air and controlled 
atmosphere (CA) and their quality was assessed after long-term storage. 
Results for analyses from 1977 through 1984 are summarized in Table 1. It can 
be seen that gypsum treatments increased Ca concentrations in both leaves and 
fruit. In addition, they suppressed magnesium (Mg) in both leaves and fruit, 
and suppressed potassium (K) in the fruit but not the leaves. Treatment had no 
effect on phosphorus (P) levels in either fruit or leaves. 

The increased fruit Ca levels improved keeping quality of the apples 
(Table 2). Both bitter pit and senescent breakdown were significantly reduced 
after both air and CA storage. In the case of bitter pit, the reduced levels 
of both Mg and K in the fruit should enhance the benefit from increased Ca, 
since it has long been known that high Mg and K worsen the effects of low Ca in 
causing bitter pit development. It should be noted that in 1985 there was a 
severe bitter pit problem in the fruit on the trees. As we walked through this 
block it was very clear which trees had and had not been treated with gypsum, 
as the appearance of the fruit was markedly different. In contrast, little 
bitter pit occurred in this block in 1986 and no difference was apparent at 
harvest time . 

The second gypsum experiment was established in 1980 in a block of 
Delicious trees planted on MM. 106 rootstock in 1972. This experiment was set 



up and conducted by Dr. William J. Lord until his retirement. The trees in 
this block received either 0, 50, or 100 lbs. of gypsum spread beneath the 

Table 1. Effects of annual gypsum applications of 80 lbs. per tree beneath the 
canopy in the spring on fruit and leaf mineral concentrations. Cortland. 
1977-1984. 



Element 



Treatment 



Ca (ppm fruit, 
% d.w. leaves) 



Mg (ppm fruit, 
% d.w. leaves) 



K (%) 



P (ppm fruit, 
% d.w. leaves) 



Fruit 



No gypsum 
Gypsum 



142 
162 



303 

273 



0.63 
0.60 



420 

417 



Significance^ 



•kiiic 



*** 



** 



n.s . 



No gypsum 
Gypsum 





Leaves 




0.82 


0.26 


1.36 


0.96 


0.23 


1.39 



1.90 
1.86 



Significance^ 



iiik-Jc 



*** 



n.s . 



n.s , 



'Significance: *** = odds of 999:1; ** = odds of 99:1; n.s. = not significant 



Table 2. Effects of annual gypsum applications, 1977-1984, on fruit quality, 
Cort land . 



Factor 



No gypsum Gypsum Significance^ 



Firmness , 


lbs 


. , harvest 


13.4 


After 


air 


stg 


9.2 


After 


CA 




11.0 


Bitterpit , 


, %, 


after air stg 


8 


After 


CA 




11 


Breakdown. 


1 "> J 


after air stg 


20 


After 


CA 




8 



13.5 

9.3 

11.1 

3 
5 

12 
3 



n.s. 
n.s ■ 
n.s . 

*** 

•kick 

*** 
■k-k-k 



'Significance: *** = odds of 999:1; n.s. = not significant, 



canopy in April. These treatments were repeated each year until 1986, when the 
100-lbs. application rate was discontinued. Each year leaves and fruit were 
analyzed, and when available (the site is subject to frost), fruit were stored 
in 320F air and assessed after long-term storage. 

Results are summarized in Table 3. Gypsum increased Ca concentrations in 
both leaves and fruit, and decreased Mg concentrations in both leaves and 
fruit. It did not affect fruit K and slightly increased leaf K. Gypsum ut 100 
lbs. per tree was no better than 50 lbs. per tree in any of these measurements. 

Table 3. Effects of annual gypsum applications, 1980-84, on leaf and fruit 
mineral concentrations. Delicious. 



Gypsum (lbs. /tree) Significance^ 



Factor 50 100 vs 50 vs 

50 + 100 100 



n. 


s 


n. 


s 


n. 


.s 


n. 


,s 


n, 


.s 


n, 


,s 



Fruit Ca, ppm 145 153 152 * 

Mg, ppm 263 258 255 ** 

K, Z 0.54 0.55 0.55 n.s. 

Leaf Ca, % 1.22 1.32 1.36 ** 

Mg, % 0.36 0.32 0.32 ** 

K, % 1.36 1.42 1.43 ** 

zsignif icance: ** = odds of 99:1; * = odds of 19:1; n.s. = not significant. 

In this experiment no consistent effect on fruit quality has been 
measured. In part this probably is due to the large variability in cropping 
among trees, and the consequent variability in fruit quality. For example, in 
1986 a severe bitter pit problem existed but it was found only on the large 
fruit that were produced on trees that had been damaged by frost. The large 
effect of fruit size may have masked any possible benefit from the gypsum 
treatments . 

These results indicate that soil applications of gypsum beneath the tree 
can increase apple Ca concentrations and improve fruit quality after storage. 
The effects are modest in size but can produce measurable benefit under 
appropriate conditions. 

Use of gypsum can, however, create some problems. The obvious one is 
suppression of leaf Mg levels. Mg deficiency is common in Massachusetts and 
results in loss of vigor and productivity of trees. Our results have shown a 
steady decline in leaf Mg in the Cortland block with continuing gypsum 
application. Each year leaf Mg was lower than it was the previous year in the 
gypsum-treated trees. Clearly, Mg levels would have to be monitored carefully 
and corrective measures applied as needed if a gypsum program was adopted. 



We do not know what effects long-term use of gypsum would have on soil 
properties. These effects must be determined in future assessments. 

Likewise, we do not know what application rate is optimum. Since spread 
of the trees was different in the Cortland and Delicious blocks, it is more 
useful to consider applications in terms of lbs. per square foot. The Cortland 
trees were treated with 0.2 lbs. per sq. ft. annually, and the Delicious trees 
with 0.3 and 0.6 lbs. per sq. ft. Since the higher rate on Delicious was no 
different from the lower rate, it appears that something less than 0.3 lbs. per 
sq. ft. may be optimum. However, a comprehensive experiment needs to be 
conducted to determine effective rates. 

Gypsum treatments are both laborious and expensive when applied as we did. 
The material was evenly spread under the trees, a slow unpleasant task. Our 
price for gypsum was approximately $0.08 per pound, and therefore the treatment 
cost between $3 and $5 per tree per year using the rates reported here. 
However, we do not know if gypsum needs to be applied annually. In 1986 the 
100 lbs. per tree treatment under Delicious was discontinued, but fruit mineral 
analyses showed that Ca level remained equal to that of fruit no longer 
receiving gypsum. 

At this time, 1 view soil gypsum treatment as an effective way to raise 
fruit Ca levels when it is applied as we have. Perhaps the best way to use 
gypsum is in an orchard or a block that is known to consistently produce low- 
Ca apples. We have another block of Cortland trees that is in very fertile 
soil and which produces excessive vigor and large fruit, and these fruit are 
always badly affected with bitter pit and breakdown. In 1986 we established an 
experiment in this block to see if we can improve fruit quality through gypsum 
treatments. Our data show that treatments did not influence mineral 
concentrations in this first year. Fruit were not analyzed the first year in 
either of the earlier experiments, so this is the first time in which we can 
determine the rate at which fruit mineral levels change over time. Based on 
the earlier studies, we should see improvements next year. 

1 have tried to emphasize that use of gypsum is still very experimental. 
It will take a number of years before we can make recommendations with 
confidence. However, it is obvious from the results shown here that soil 
gypsum treatments can improve fruit Ca levels and quality under some 
conditions. It is therefore a new weapon in the modern apple grower's arsenal 
of techniques for coping with the ongoing threat of Ca deficiency in fruit. 



POMOLOGICAL PARAGRAPH 

Reducing Fruit Load on Tree Leaders 

Growers should avoid allowing too many fruit to develop on the leader of 
young trees. It may be advantageous to remove fruit from the entire tree until 
the fourth year. Then for the succeeding years, depending upon tree size, the 
removal of fruit from the leader should be continued. 



5 

CAN ROOTSTOCK AFFECT APPLE RIPENING AND QDALITY?^ 

Wesley R. Autio 

Department of Plant and Soil Sciences 

University of Massachusetts 

Interest in the effects of rootstocks on fruit ripening and quality began 
a number of years ago. In 1930 Wallace (7) published data suggesting that 
apples from trees on M.9 rootstocks had higher soluble solids (sugar) levels 
and did not store as well as fruit from trees on other rootstocks. However, if 
fruit from trees on M.9 were harvested earlier than others, then similar 
storability was obtained, suggesting that M.9 encouraged earlier ripening. In 
1944 Hewetson (4) published similar results using Mcintosh trees with various 
interstocks. Fruit from trees with an M.9 interstock matured and colored 
earlier. Perry and Dilley (6) confirmed these results using the ethylene 
climacteric as an index of ripening. In their study Empire apples on MM. Ill 
with an M.9 interstock entered the climacteric significantly sooner than those 
on MM. Ill alone. 

Lord et al. (5) used the ethylene climacteric and soluble solids as the 
primary indices of Empire apple ripening and compared various interstock- 
rootstock combinations with M.26, M.9, and M.27. They found few consistent 
differences with respect to the percentage of fruit in the ethylene climacteric 
5 days after harvest. However, consistent differences existed in soluble 
solids content. Fruit from trees on M.27 had significantly higher soluble 
solids than fruit from trees on M.26, with fruit from trees on M.9 intermediate 
between the two. These results suggested that M.27 encouraged earlier ripening 
than M.26, and possibly M.9. 

Fallahi et al. (2, 3) compared the ripening and quality of fruit from 
Golden Delicious trees on seedling roots, M.l, M.7, M.26, MM. 106, and OAR 1. 
Using ethylene measurements they found that fruit from trees on M.26 appeared 
to ripen earliest, and those from trees on OAR 1 ripened substantially later 
than those from all other trees. However, OAR ] also had the highest percent 
soluble solids, which is difficult to explain. 

It is difficult, from the small number of studies, the small range of 
rootstocks used in each study, and the somewhat inconsistent results to compose 
a clear picture of the effects of rootstock on apple ripening and quality. The 
objective of this study was to use a range of rootstocks, from the very 
dwarfing M.27 to the very vigorous MAC 24, to assess rootstock effects on 
ripening, size, and quality. 

Materials and Methods 

Starkspur Supreme Delicious trees on 9 rootstocks (Ott.3, M.7 EMLA, M.9A 
EMLA, M.26 EMLA, M.27 EMLA, M.9, MAC 9 (Mark), MAC 24, and OAR 1) were planted 
in a randomized complete block design with 10 replications at the University of 



^This work was supported in part by a grant from the International Dwarf 
Fruit Tree Association. 



Massachusetts Horticultural Research Center in Belchertown, MA. To assess the 
effects of rootstock on fruit ripening, quality, and size, 7 of the 10 
replications were used, 5 planted in 1980 and 2 planted in 1981. 

Starting on September 15, 1986, and continuing at 5 day intervals until 
October 5, four fruit from each tree were harvested for the measurement of 
internal ethylene levels. One-ml gas samples were taken from the core of each 
apple to determine the ethylene concentration. 

On September 29, 1986 ten fruit were harvested from each tree for the 
assessment of fruit weight, length/diameter (L/D) ratio, flesh firmness, 
percent soluble solids, and watercore incidence. Firmness was measured with an 
Effegi Penetrometer with a 1 cm head. The percent soluble solids was assessed 
with a hand ref ractometer , and watercore was characterized by visual assessment 
using the method of Bramlage and Lord (1). 

Results and Discussion 

Table 1 reports the fruit weight, firmness, L/D ratio, percent soluble 
solids, and watercore incidence. To accurately assess the effects of rootstock 
on fruit size it is necessary to account for crop load. Table 1 also includes 
an estimate of crop load in terms of weight of fruit per unit of trunk cross- 
sectional area. Additional statistical analyses were performed on these data 
to remove the effect of crop load from that of rootstock, and the differences 
shown in Table 1 are true estimates of the effects of rootstock on size. Trees 
on M.9 produced the largest fruit and those on M.27 EMLA and OAR 1 produced the 

Table 1. Fruit parameters and crop load for Starkspur Supreme Delicious trees 
on various rootstocks. 





Fruit 




Flesh 




Soluble 










weight 




firmness 


L/D 


solids 


Watercore 


Crop ] 


Load 


Rootstock 


(g) 




(kg) 




ratio 


(%) 


index^ 


(kg/cm2 


TCAY) 


Ott.3 


184 


cX 


8.39 


b 


0.97 ab 


11.6 abc 


2.0 ab 


0.98 


ab 


M,7 EMLA 


196 


ab 


8.57 


b 


0.99 a 


11.1 be 


1.8 ab 


0.72 


be 


M.9 A EMLA 


192 


b 


8.34 


b 


0.97 ab 


11.4 abc 


2.0 ab 


1.33 


a 


M.26 EMLA 


175 


d 


8.57 


b 


0.96 be 


11.3 abc 


1.8 ab 


0.92 


ab 


M.27 EMLA 


157 


e 


8.89 


a 


0.94 c 


12.0 a 


2.4 a 


0.91 


ab 


M.9 


200 


a 


8.39 


b 


0.95 be 


11.8 ab 


2.3 a 


0.95 


ab 


MAC 9 


177 


cd 


8.34 


b 


0.95 be 


10.9 e 


1.4 b 


1.25 


a 


MAC 24 


193 


ab 


8.48 


b 


0.97 ab 


11.1 be 


2.4 a 


0.42 


cd 


OAR 1 


153 


e 


8.98 


a 


0.97 ab 


11.4 abc 


2.2 a 


0.27 


d 



^Watercore index: 1 = not present; 5 = most severe. 

yTCA = trunk cross-sectional area. 

^Means in a column not followed by the same letter are significantly different, 



smallest. Note that trees on M.27 EMLA and M,9 had similar crop loads and 
trees on OAK 1 had a very light crop, suggesting a substantial effect of 
rootstock on fruit size. • 

Few differences were seen in fruit firmness (Table 1) and those that were 
present can be attributed to size, the smaller fruit being firmer. The L/D 
ratio (Table 1) was highest for fruit from trees on M.7 EMLA and smallest for 
fruit from trees on M.27 EMLA. The differences were statistically significant 
and may be of commercial importance. 

The percent soluble solids (Table 1) was highest for fruit from trees on 
M.27 EMLA, whereas it was the lowest in fruit from trees on MAC 9. 
Furthermore, watercore was most prominent in fruit from trees on M.27 EMLA and 
MAC 24 and least prominent in fruit from trees on MAC 9. This relationship 
suggests that there may be significant differences with respect to the timing 
of fruit ripening, but soluble solids and watercore are not very accurate 
indices of fruit ripening. 

During the course of ripening, apples exhibit a very rapid rise in the 
biosynthesis of ethylene, a gaseous plant hormone. Within the core area the 
concentration of ethylene rises with the increase in biosynthesis, providing a 
very accurate means of comparing the times of ripening. Figure 1 shows the 
internal ethylene concentration of apples from trees on M.27 EMLA, M.7 EMLA, 
and MAC 9. Other rootstocks were deleted from the graph to avoid confusion, 
but were roughly grouped into 3 patterns. Generally, M.27 EMLA (along with 
Ott.3, M.9, and M.9A EMLA) encouraged the earliest increase in internal 
ethylene. M.7 EMLA (along with M.26 EMLA, MAC 24, and OAR 1) resulted in a 
somewhat later rise, and MAC 9 delayed the increase in internal ethylene. 



12 



Ethylene (ppm) 



10 h 

8 



2 - 



M.27 EMLA 



M.7 EMLA 



— *— 
9/15 




MAC 9 



A 



9/20 



9/30 



10/5 



Figure 1. The internal ethylene concentration of Starkspur Supreme Delicious 
fruit immediately after harvest from trees on MAC 9, M.7 EMLA, or M.27 EMLA. 



8 

Figure 2 shows the moan internal ethylene concentration for all harvests, 
and it is obvious that M.27 fclMLA and Ott.3 resulted in higher levels and MAC 9 



0.8 



Ethylene (ppm) 




0.0 



Ott.3 M.7E M.9AE M.26E M.27E M.9 

ROOTSTOCK 



MAC9 MAC24 OARl 



Figure 2. The mean, internal ethylene concentration of fruit harvested 
September 15, 20, 25, and 30 from Starkspur Supreme Delicious trees on the 
rootstocks included in this study. E refers to those rootstocks derived from 
EMLA clones. Bars with different letters represent means that are 
significantly different at the 5 % level (Duncan's New Multiple Range Test). 



resulted in lower levels. These data confirm the effect of these rootstocks on 
ripening, showing a significant delay in the rise in internal ethylene caused 
by MAC 9 and enhancement caused by M.27 EMLA and Ott.3. Additional 
confirmation is provided by the data in Figure 3. This graph shows the 
postharvest ripening rate of fruit from trees on the various rootstocks. Fruit 
from trees on MAC 9 ripened the slowest and those from trees on M.27 EMLA 
ripened fastest, suggesting that the fruit from MAC 9 were less mature when 
harvested than those from M.27 EMLA. 

The ethylene measurements support the suggestion of the soluble solids and 
watercore data that M.27 EMLA encouraged earlier ripening, whereas MAC 9 
delayed ripening. 



Cone lusions 



The results from the first year of this study suggest that rootstocks can 
alter fruit size, fruit quality (in terms of soluble solids and the incidence 
of watercore), and the time of fruit ripening. In 1986 M.9 resulted in the 



largest fruit, while M.27 EMLA and OAR 1 resulted in the smallest fruit. 
Ripening was enhanced by M.27 EMLA, resulting in higher soluble solids levels, 
more watercore, an earlier increase in internal ethylene, and faster post- 



Days to 1 ppm Ethylene 




Ott.3 M.7E M.9AE M.26E M.27E M.9 

ROOTSTOCK 



MAC9 MAC24 OARl 



Figure 3. The mean, postharvest ripening rate (days to reach 1 ppm internal 
ethylene) of fruit harvested September 15 and 20 from Starkspur Supreme 
Delicious trees on the rootstocks included in this study. E refers to those 
rootstocks derived from EMLA clones. Bars with different letters represent 
means that are significantly different at the 5 % level (Duncan's New Multiple 
Range Test). 



harvest ripening rate. MAC 9 delayed ripening, resulting in lower soluble 
solids levels, less watercore, a later increase in internal ethylene, and a 
slower postharvest ripening rate. Study of these effects will continue in 1987 
to confirm the results presented here. 

Are rootstock effects on fruit ripening of commercial significance? The 
delay that may be provided by MAC 9 (Mark) may only be a few days, but it may 
be of some help in expanding the harvest season for a single cultivar. Strains 
of some cultivars are now available which ripen somewhat earlier than normal. 
If these strains are combined with rootstocks which encourage earlier ripening 
and the standard strains are combined with rootstocks, like Mark, which delay 
ripening, significant expansions of the harvest season may be obtained. If 
Alar* is not available for drop control in the future, it will be necessary to 
use techniques like the one suggested here for cultivars such as Mcintosh to 
allow harvest of the entire crop. 



10 
Literature Cited 



1. Bramlage, W. J. and W. J. Lord. 1967. Watercore and internal breakdown 
in Delicious apples. University of Massachusetts Cooperative Extension 
Service Publication No. 11. 

2. Fallahi, E., D. G. Richardson, and M. N. Westwood. 1985. Quality of 
apple fruit from a high density orchard as influenced by rootstocks, 
fertilizers, maturity, and storage. J. Amer. Soc . Hort . Sci. 110:71-74. 

3. Fallahi, E., D. G. Richardson, and M. N. Westwood. 1985. Influence of 
rootstocks and fertilizers on ethylene in apple fruit during maturation 
and storage. J. Amer. Soc. Hort. Sci. 110:149-153. 

4. Hewetson, F. N. 1944. Growth and yield of Mcintosh apple trees as 
influenced by the use of various intermediate stem pieces. Proc . Amer. 
Soc. Hort. Sci. 45:181-186. 

5. Lord, W. J., D. W. Greene, R. A. Damon, Jr., and J. H. Baker. 1985. 
Effects of stempiece and rootstock combinations on growth, leaf mineral 
concentrations, yield, and fruit quality of 'Empire' apple trees. J. 
Amer. Soc. Hort. Sci. 110:422-425. 

6. Perry, R. L. and D. R. Dilley. 1984. The influence of interstem on 
ripening indices of 'Empire' apples. Compact Fruit Tree 17:50-54. 

7. Wallace, T. 1930. Factors influencing the storage qualities of fruit. 
Proc. 1^*- Imperial Horticultural Conference, London. 



***** 

P(M10L0GICAL PARAGRAPH 

Pruning Well-feathered Trees at Planting 

William J. Lord 

Department of Plant and Soil Sciences 

University of Massachusetts 

If you receive well-feathered trees from the nursery, it is important to 
leave as many favorably positioned branches on the trees as possible, because 
when all but 2 or 3 branches are removed, these tend to grow very vigorously 
and develop narrow crotch angles when growing conditions are favorable. Head 
the trees at 39 inches, or 10 to 12 inches above the highest, useful branch, if 
the tree is well feathered. Do not head the branches, or remove any more low 
branches than necessary. Heading adds to the problem of excessive vigor on 
vigorous cultivars and delays production. Low branches contribute to the total 
leaf surface of the tree. Low branches and extra scaffold limbs can be removed 
in subsequent years. 



11 

A REPORT ON THE 1986 MASSACHUSETTS APPLE IPM PROGRAM 

William M. Coli, Daniel R. Cooley, Kathleen Leahy, and Ronald Prokopy 

University of Massachusetts 

Acknowledgements: We would like to thank Keith Bohne , Bill and Henry 
Broderick, Dana Clark, William Flint, Jesse and Wayne Rice, Ed Roberts, and 
Tony Rossi for their cooperation. We also thank Glenn Morin and Robin Spitko 
(New England Fruit Consultants) for their scouting reports which we included in 
the weekly pest message on several occasions, and for the harvest injury data 
in Table 1. Special thanks to Sue Butkewich and Tom Green. 

Program funding was provided in part by U.S.D.A. (Smith-Lever 3(d) Pest 
Management), the Massachusetts Department of Food and Agriculture, and grower 
contributions. Individual grower support of the Apple IPM program and the Pest 
Alert messages totalled $2870 in 1986, an increase from 1985. In addition, the 
Massachusetts Fruit Growers Association, Inc. provided a grant of $1,600 which 
was used to replace the aging IPM vehicle. Our "new" vehicle, which we use to 
travel to monitored orchards and research sites, is a 1983 Ford LTD, and has 
already begun to develop a sticky trunk. We sincerely wish to thank the 
growers and the MFGA for their continued interest in and support of the 
program. 

Five commercial orchard blocks (plus a San Jose scale-infested commercial 
block in Lancaster) and one block at the Horticultural Research Center (HRC) 
were monitored weekly for arthropods and pathogens affecting fruit trees. Scab- 
infested leaves which had been placed in wire cages at these 6 sites in March 
were collected weekly and examined using squash mounts and counts of mature 
ascospores, to determine apple scab spore maturity. In addition, temperature 
and rainfall were recorded at the Horticultural Research Center (HRC), and 
other pest information was gained by occasional orchard visits and reports 
from Sue Butkewich, Tom Green, growers, Extension workers in other states, and 
private-sector consultants. 

This information was used to reply to grower calls and write twice-weekly 
Entomology Pest Messages from April 8 to September 10. Plant Pathology messages 
were written weekly during the primary scab season, and in response to observed 
problems afterwards. Messages initially were transmitted to regional agents via 
the University computer's mail program, but after August 1 were shifted to a 
grant-funded, microcomputer-based, bulletin board system (BBS) called INFONET. 

Entomology and Plant Pathology staff made a combined total of about 100 
orchard site visits during the year, assessing pest problems faced by large and 
small commercial orchardists. Staff also gave 27 Extension talks at grower and 
other group meetings and 2 talks at professional association meetings, and 
authored or co-authored 5 Fruit Notes articles and several journal or 
proceedings articles. Entomology staff again cooperated with Dr. Rick Weires, 
Hudson Valley Lab, on the Annual March Message. Bill Coli gave an invited talk 
at the 29^*^ annual meeting of the International Dwarf Fruit Tree Association, 
entitled "Techniques of Integrated Pest Management for Commercial Orchards." 
Plant pathology initiated cooperative research on delayed, early-season 
spraying with Dr. William MacHardy of the University of New Hampshire and Dr. 
David Rosenberger, Hudson Valley Cooperative. 



12 

At 4 Twilight meetings in each of the 3 regions, growers were provided 
with extensive IPM training including 2 hours at each session covering sprayer 
calibration using the Tree-Row-Volume method. These calibration sessions 
provided a total of about 450 grower-training-hours, all suitable for pesticide 
applicator certification credits. A 5-page handout titled "Calibration of 
Orchard Sprayers Using the Tree Row Volume Method" prepared by entomology staff 
was distributed at these meetings. This information is also being incorporated 
into a computerized expert system which should be publicly available in the 
near future. We would like to acknowledge the support and assistance of Mr. 
Bill Doe, Doe Ag. Sales, and Mr. Rick Clark, Orchard Equipment and Supply, who 
provided substantial expertise in fine-tuning the calibration of several 
diverse types of sprayers. We also would like to acknowledge the contribution 
of the Regional Agents who assisted in presenting this material at the twilight 
meetings . 

Fungicide, insecticide, and insect growth regulator trials were again 
performed at the HRC and at grower sites, testing chemicals which may be or 
presently are a component of commercial spray programs. Evaluation of pesticide 
effects on mite predators continued as did evaluation of disease-resistant 
apple cultivars. A commercial test block of disease-resistant cultivars planted 
in a randomized block design was established at the Rice farm in Wilbraham. 
This planting is intended to assess the feasibility of using no fungicides and 
a minimum of insecticides in a commercial setting, and to define further 
horticultural characteristics and marketability of these cultivars. 

Related Entomology research and adaptive studies continued to focus on 
evaluation of selective, relatively non-toxic pesticides and development of 
monitoring traps for Tentiform Leafminer, on timing of plant bug injury and 
pesticide treatment for plant bug, and on the behavioral ecology of the Apple 
Maggot Fly and the Plum Curculio. Other Entomology studies involved a test of 
several visual traps for monitoring the Walnut Husk Maggot (an occasional peach 
pest), a project to collect and identify unusual mite predators first found 
last season in a low-spray orchard in Stow, MA, and, in cooperation with Dr. 
Alan Eaton, University of New Hampshire, a survey to determine the distribution 
in Massachusetts of Psylla mali , the European Apple sucker. P . ma 1 i is not 
found as a pest in commercial orchards, but appears to be expanding its range 
and may become a pest in commercial blocks in the future. 

Insect/Mite Pest Status and Harvest Injury, 1986 

Tarnished plant bug - TPB was once again the number one cause of insect 
injury in the state's commercial apple orchards. In one block we visited 
weekly, no pre-bloom insecticide was applied, and on-tree injury reached 4%. 
However, most "dimples" were in or near the calyx, and would not likely have 
resulted in fruit downgrading. 

Plum curculio - Extremely favorable weather in late May caused PC to 

emerge in most areas over a very short period of time, allowing some growers to 

control PC with one insecticide application. In a few locations, however, PC 
egglaying scars were seen in late June and early July. 

Apple maggot fly - Trap captures continued this year into October in all 
areas of the state, although overall numbers of AMF captured were not high, and 
only one Extension-monitored block sustained any injury. Again this year peak 



13 

captures occurred in September in commercial blocks and in Dr. Prokopy's 
orchard. 



Table 1. Percent insect-injured fruit in on-tree surveys of 53 commercial 
blocks, 1986, compared to orchard harvest injury averages from 1978-1985. 



Insect pest 



Percent injury^ 



1986 



1978-1985 



Tarnished plant bug 
European apple sawfly 
Plum curculio 
San Jose scale 
Leafrollers 
Green fruitworms 
Apple maggot fly 
Other 



0.83 
0.01 
0.75 
0.11 
0.02 
0.03 
0.05 
0.02 



1.74 
0.40 
0.51 
0.74 
0.03 
0.08 
0.06 
0.01 



^Data provided by New England Fruit Consultants. Sample consisted of 50 fruit 
per tree on 6 to 16 trees per block, depending on block size. 

Apple leafminers - Sticky, red, visual traps again were very useful in 
predicting potential LM problems prior to bloom. Traps in 3 of 6 blocks 
indicated the need to treat, later borne out by counts of sap-feeding mines. In 
2 other blocks, overwintering generation moth captures remained just below the 
provisional action threshold (12 moths per trap), and first and second 
generation mines likewise never exceeded the economic injury level. In one of 
these blocks (which also sustained high levels of white apple leafhopper injury 
and received no Alar®) we noted a higher level of pre-harvest drop than was 
seen in other monitored sites. 

White apple leafhopper - White apple leafhopper was again a problem at 
many sites in 1986, especially where l^'- generation activity was not noted and 
controlled, or where only organophosphate insecticides were used against the 
OP-resistant leafhoppers. A few blocks experienced serious, late-season WAL 
buildup. Also, see later section on potato leafhopper. 

Mites - In most orchards mite numbers were very low this year, possibly 
due to frequent, heavy rains throughout the summer. A. fallacis predator 
numbers were very high in all locations compared to recent years, and seemed to 
be thriving despite the shortage of red mite adults. 

Disease Situation 



The 1986 season was characterized by extreme disease pressure largely 
caused by prolonged wet weather and low temperatures. The major efforts of the 
program were to monitor Venturia inaequalis ascospore maturity from April 



14 

through mid-June, to develop weekly messages and distribute them to Regional 
Fruit Agents, to test new ergos terol-synthesis inhibiting fungicides for 
potential use in the program, to continue with work on disease-resistant 
apples, and to participate in grower training sessions for sprayer calibration 
and disease-management information. 

Leaves for the apple scab maturity assay were collected from an abandoned 
orchard in November, 1985, placed in hardware-cloth cages, and left out in a 
non-sprayed orchard over the winter. These cages were distributed to the 6 
sites in March. Weekly collections were made by Kathleen Leahy, Jim Williams, 
and Bill Coli. Leaves were then examined, squash mounts prepared, and counts of 
mature ascospores made. 

Squash mount data indicated that primary season lagged behind tree 
development by up to 2 weeks. This meant that early season sprays were not 
needed. In most areas, fungicide applications could have been delayed until 
half-inch green or tight cluster at the earliest. In fact, no fungicides 
probably were necessary until bloom this year. Wetting periods monitored at 
Belchertown showed that there were no Mill's infection periods before May 7, 
because during wet periods weather was too cool for scab development. At this 
time most trees were in early bloom. There were several heavy infection periods 
through the rest of May. A heavy wetting period (72 hours) occurred June 5-8, 
and the effects of this are still being discussed. Scab development on late 
terminals during the end of June suggested that there was a primary infection 
period at the beginning of the month, and that the maturity evaluations had 
estimated the end of the season before it had occurred. The alternative 
suggestion is that during mid-May, primary infections occurred, and during the 
heavy rains in early June, secondary scab was spread. Scouting in the tops of 
trees showed lesions on early terminals and clusters, indicating that these 
infections had occurred in mid-May. Because of frequent rains, extreme 
pressure continued through the summer, causing greater than normal fruit scab 
in some orchards. 

Pest messages have stressed the need to scout orchards until infections 
which might have occurred have had a chance to show up. During this period, 
sprays should be applied as they were during primary season. However, some 
growers immediately reverted to a reduced frequency and/or rate in their spray 
schedule at the announced termination of primary season. In our tests, such a 
reduction this year resulted in terminal scab infections of the type reported 
around the state. This confirms our original recommendation: after the end of 
primary season, orchards must continue to be sprayed on a primary schedule for 
a period sufficient to allow any primary infection to be visible. 

Other infections appeared to be caused by a failure to spray before or 
immediately after critical infection periods in May, or by a failure to cover 
the tops of large trees. Large trees were infected much more frequently than 
properly pruned trees on dwarfing rootstocks. Scouting the tops of trees 
revealed primary infections better than scouting other locations. 

Tests at the HRC also looked at the efficacy of 3 ergosterol-inhibit ing 
(EI) fungicides, Rubigan'" (Elanco) , Nustar'" (Dupont), and A-815'" (Uniroyal) 
and compared them to a standard dithiocarbamate, Manzate™ 200. In some 
treatments, the EI compounds were combined with the Manzate. In general, 
sterol-inhibit ing fungicides were better than Manzate at controlling primary 



15 

scab. Nustar was superior to other materials. These materials can be applied 
on an after-infection basis up to 96 hours following the initiation of an 
infection. Next season, the upper limits of this time will be tested. In 
addition, an application of one or more of these materials will be made this 
fall to determine whether they have any effect on the ability of the fungus to 
overwinter and produce ascospores in the spring. The tests at the HRC 
represented a 150% increase over such tests in previous years. 

There were no reports this year of the bud blast or cankering attributed 
to fire blight on Marshall Mcintosh. The summer may have been too cool for 
development of the disease, though fire blight did show up in at least one 
commercial orchard. Alternatively, dormant copper or Bordeaux treatments or 
in-season streptomycin may be alleviating the problem. 

New or Unusual Outbreaks 

Potato leafhopper - Widespread leaf yellowing of apple throughout 
Massachusetts has been identified by New York state entomologists as injury 
caused by the potato leafhopper. Leaf injury, a diffuse yellowing of 
consecutive terminal leaves, results from PLH feeding, during which leafhoppers 
inject a toxic saliva. Injury shows up later, often after leafhoppers have 
left. With no insects present, PLH injury can easily be mistaken for nutrient 
deficiency. PLH does not overwinter in the region, but is "imported" from 
southern states as storms move up the coast. Because the summer of 1986 was 
characterized by a greater than normal frequency of such storms, PLH numbers on 
several crops were unusually high. 

Catfacing insects on peaches - Catfacing continued well into the summer on 
peaches in many locations this year, with injury occurring at one monitored 
site in early August. The causative agent is not known, although a rather 
damaged specimen which may have been oak hickory plant bug showed up on an AMF 
sphere in late July. We will be monitoring the situation closely in 1987 to 
determine if other pests such as stink bugs might be causing this injury. 

European corn borer - A grower located close to a corn field experienced 
late season damage from ECB - larvae tunneling into the calyx and through the 
core of the fruit. Growers in similar situations would be well advised to 
monitor ECB populations in August and September. Also, early in the season, 
one grower reported damage to terminal growth of young trees apparently caused 
by an insect larva which was collected and tentatively identified as ECB. 

Plans for 1987 

We will be increasing the number of monitored orchards from 6 to 10 in 
1987; two of these sites will very likely be low-spray orchards. In addition, 
we will be monitoring a number of peach and pear blocks for borers, catfacing 
insects, psylla, and peach X-disease as well as other problems which may become 
apparent . 

The INFONET computerized bulletin board, operated in cooperation with Dr. 
Wesley Autio, Department of Plant and Soil Sciences, will be maintained and 
expanded in 1987. This BBS is the primary means of disseminating topical pest 
management and horticultural information, pesticide registration news, meeting 
dates, etc. to regional agents and other interested parties. INFONET will 



16 

continue to be directly accessible to growers with telecommunication ability. 
The BBS number in Amherst is 413-545-4717. For information or a user manual, 
please call Bill Coli or Kathleen Leahy at 413-545-2283 or Wes Autio at 413- 
545-2244. 

We propose to continue most 1986 activities, including: monitoring 
weather, pathogens, arthropods, and tree development in 10 commercial blocks, 
writing twice-weekly pest messages, presenting 4 grower training sessions in 
each of the 3 regions, performing adaptive studies and pesticide trials, 
authoring extension and other publications, and generating outside funding. In 
addition, we plan to provide continued support of the National Park Service IPM 
Program at Adams National Historic Site, which will generate $500 to partially 
support the Apple IPM technician. If 2 grant applications we have submitted 
are approved, we will also be initiating a large-scale study in commercial 
orchards on the influence of ground cover on mite predator prey interactions 
and buildup of scab inoculum and a study aimed at implementing very low spray 
programs using traps for controlling directly apple maggot flies. 

Calibration will be emphasized, although not as intensively as in 1986. 
Every attempt will be made to coordinate Entomology and Plant Pathology 
scouting, with increasing emphasis planned for looking for disease incidence in 
commercial and abandoned orchards. 

We plan to develop computerized expert systems to diagnose and advise on 
problems. Initially, these will be for use by regional agents, though it is 
hoped that growers will have access to them in the near future through INFONET. 
At present, we have initiated work on root disorder diagnostics, fruit 
disorders diagnostics, scab fungicide application recommendations, and sprayer 
calibration. This work is also supported in part by the College of Food and 
Natural Resources, and in part by a Public Service Endowment from the 
University . 



POMOLOGICAL PARAGRAPH 

Early, Heavy Cropping of Apples 

William J. Lord 

Department of Plant and Soil Sciences 

University of Massachusetts 

Early, heavy cropping of apple trees is not always desirable when trees 
are planted at wide spacings. Early, heavy cropping may stunt the trees. This 
situation has been observed in a row of Cortland on M.26 with the severity of 
stunting varying considerably within the row. Therefore, we may find that in 
some instances heading back cuts on the extension growth of the central leader 
and on shoots of the scaffold (framework) branches is desirable. This 
procedure will stiffen the central leader and scaffold branches, promote 
growth, and delay fruiting. An alternative to heading cuts is defruiting. 



17 
RESULTS OF 1986 CHEMICAL THINNING TRIALS ON MCINTOSH 



Duane W. Greene and Wesley R. Autio 

Department of Plant and Soil Sciences 

University of Massachusetts 

Chemical thinning is one of the most critical activities undertaken by 
apple growers each year. Effective thinning can mean the difference between 
profit and loss not only the year of application but also the following year. 

There have been no new chemical thinning agents registered in 
Massachusetts in more than 20 years. However, during this period of time there 
has been a steadily increasing demand for larger apples. We are continually 
looking for new and better thinning agents, but until these are found and 
registered it will be necessary to use more effectively those thinning agents 
that are presently available. 

Experiments were initiated at the Horticultural Research Center in 
Belchertown in 1986 with two goals in mind: 1) evaluate the effectiveness of 
several thinning treatments and combinations in an attempt to identify 
promising treatments for future recommendations, and 2) determine the 
importance of bloom intensity on final fruit set following a chemical thinning 
treatment . 

Experiment One 

Mature Mcintosh trees (M.7 rootstock) with a heavy bloom were selected for 
Experiment One. Thinning treatments were applied 16 days after full bloom on 
May 26, 1986, when fruit diameter was approximately 10 mm. Treatments used 
were: naphthaleneacetic acid (NAA) at 5 or 7.5 ppm and benzyladenine (BA) at 
50 ppm. These were applied alone as a dilute spray or in combination with 1 
lb. carbaryl (50 % WP) per 100 gal. One group of trees received no chemical 
thinning spray and one received only carbaryl. After June drop all fruit on 
previously tagged limbs were counted and fruit set was calculated. A 30-apple 
sample was taken at harvest, weighed, and evaluated for percent color, flesh 
firmness, and soluble solids (sugars) content. 

Generally, a fruit density of about 5.5 to 6.0 fruit/cm limb circumference 
on Mcintosh is considered to be ideal, and all treatments thinned when applied 
alone, although only BA at 50 ppm and NAA at 7.5 ppm thinned adequately (Table 
1). When carbaryl was combined with NAA or BA additional thinning occurred. 
NAA at 7.5 ppm, BA, and carbaryl alone increased fruit size. Size was 
increased further when carbaryl was added. No chemical thinning spray 
influenced flesh firmness, soluble solids, red color, or seed number. 

Because of its detrimental effects on mite predators the use of high rates 
of carbaryl is discouraged. Attempts are being made to minimize the amounts 
used. Although the effectiveness of carbaryl is somewhat concentration 
independent, rates of 1/4 lb per 100 gal. or below may be insufficient to thin 
adequately by itself. NAA is a very effective thinning agent but it is also 
the compound most likely to over-thin. Lower rates of NAA are frequently 
chosen to reduce the chance of overthinning. Therefore, the most satisfactory 



18 

chemical-thinning treatment would be one using a moderate level of carbaryl in 
combinations with NAA. Acceptable thinning should be achieved without causing 
overthinning or severely depressing the predator mite population. 



Table 1. Effects of naphthaleneacetic acid (NAA), benzyladenine (BA), and 
carbaryl (50 % WP) on fruit set and fruit weight of Mclntosh/M.7 apple trees. 

Fruit/cm limb circumference Fruit weight (g) 

Carbaryl (1 Ib./lOOgal.) Carbaryl (1 Ib./lOOgal.) 



13.6 


ay 


8.6 


6.2 


b 


4.1 


9.3 


b 


3.8 


6.7 


b 


5.9 



130 


b 


147 


153 


a 


174 


142 


ab 


156 


150 


b 


164 



Treatment^ (-) (+) (-) (+) 



Control 
BA, 50 ppm 
NAA, 5 ppm 
NAA, 7.5 ppm 

Average 8.9 **^ 5.6 144 ** 160 

^Treatments were applied as a dilute spray on May 26, 17 days after full bloom. 
NAA was applied as Fruitone N" and carbaryl as Sevin" (50 % WP) . 

YTreatment effects on fruit set or weight were significantly different (5 % 
level, Duncan's New Multiple Range Test) if not followed by a common letter. 

^The effects of carbaryl on fruit set and fruit weight were significant at the 
1 % level (Duncan's New Multiple Range Test). 



BA is in the developmental stages as a chemical thinner. It is the only 
chemical used alone that adequately thinned Mcintosh. It has performed equally 
well as a thinner over the past 5 years on Mcintosh as well as on other 
cultivars. BA presently is being sold as a branching agent on Christmas trees 
and is also 50% of the active ingredients of Promalin'". We will continue to 
evaluate this compound. 

Experiment Two 

A block of 16-year-old Mcintosh on MM. 106 was selected, and just prior to 
bloom 70 limbs were tagged and the blossom clusters were counted. Limbs were 
selected that had a wide range of blossom densities, some having as few as 15 
and others having as many as 350. A dilute thinning spray containing 2.5 ppm 
NAA and 1 lb. carbaryl per 100 gal. was applied with an airblast sprayer on May 
27, 16 days after full bloom. Fruit set was determined at the end of June 
drop . 



19 

It was found that the greater the number of blossom clusters at bloom the 
more fruit that remained after June drop (Figure 1). However, the point that 
we would like to e;iipluisize is that it requires a large increase in the amount 
of bloom on a limb to cause a relatively small increase in fruit number. For 
example, if the bloom on a limb was increased from 5 to 10 blossom clusters per 
cm limb circumference, the fruit set after thinning would increase only from 
about 5.5 to 6.5 fruit per cm limb circumference. NAA at 2.5 ppm plus J lb. 
carbaryl per 100 gal. is a moderate thinning treatment, and adequate thinning 
was obtained on limbs with blossom densities up to 10 to 12 blossom clusters 
per cm limb circumference. NAA at 5 to 7.5 ppm plus carbaryl would have been a 
better choice for the limbs having a heavier bloom. 



25 


Fruit per cm Limb Ore. 
























20 


■ 












15 


■ 






■ 


• 
• 

• 


• 


10 
5 


• 

■ 
■ 

i^- • 

• • 
«• • 

1 I 


• 
• 


• 

• • 

I. 


• 
• 

• 
• 

• 

1 


• 
• 


a 

• • 

t 



5 10 15 20 25 

Blossom Clusters per cm Limb Giro. 



30 



Figure 1. Effect of blossom cluster density on final fruit set of Mcintosh 
apples following a chemical thinning spray of NAA at 2.5 ppm plus 1 lb carbaryl 
(50 % WP) per 100 gal. 



Although blossom density does influence fruit set, treatments can be 
selected that will operate effectively over a relatively wide range of 
densities. NAA at 3 ppm plus carbaryl at 1 lb. per 100 gal. should be 
effective on trees with low to moderate bloom, whereas NAA at 5 to 7.5 ppm plus 
carbaryl at 1 lb. per 100 gal. would be more appropriate on Mcintosh trees with 
a moderate to heavy bloom. 



***** 



20 
TIMING THE TARNISHED PLANT BUG: A TALE OF FRUSTRATION 



Ronald J. Prokopy, Susan L. Butkewich, and Thomas A. Green 

Department of Entomology 

University of Massachusetts 

In 1976 we began what turned out to be 11 consecutive years of research on 
(a) the stages of plant development during which tarnished plant bug (TPB) 
injury to apple is initiated, (b) the most efficient method of monitoring the 
appearance of plant bug adults, and (c) the efficacy of various pesticides for 
controlling plant bugs. In 4 previous issues of Fruit Notes [43(2) : 10-14, 
44(2) :l-5, 45(3):15-18, and 45(4)13-14], we reported our results of the first 4 
years. In brief, we found that (a) apple flower buds, blossoms, and developing 
fruit are susceptible to TPB feeding injury from silver tip to about one month 
after petal fall, (b) susceptibility to bud abortion (abscission) is greatest 
from silver tip until tight cluster, while susceptibility to fruit injury 
(dimples and/or scabbing) is greatest from tight cluster to a month after petal 
fall, (c) a 6 X 8 inch sticky white rectangle trap placed at knee height near 
the periphery of the tree offers an effective method of monitoring the 
abundance of TPB adults, (d) capture of 2.5 or more adults per trap from silver 
tip through tight cluster or 4.2 per trap from silver tip through midpink 
indicates an economically justifiable need for treating TPB adults with 
pesticide, and (e) no given type of pesticide guarantees a high degree of TPB 
control, though Cygon" may be the most effective material, followed by various 
synthetic pyrethroids, Guthion", Imidan", and Lorsban" or Thiodan'", in that 
order. 

One major question that emerged from the first 4 years of work was: how 
can one predict the best time to apply a pesticide against TPB? In other 
words, could one piece together knowledge of the time of greatest 
susceptibility of developing blossoms and fruit to TPB injury with knowledge of 
the time of greatest abundance of TPB adults in the orchard and determine a 
time at which pesticide application should be the most effective? For the past 
6 years (1981-1986), we have attempted to answer this question through research 
at the Horticultural Research Center in Belchertown, MA. 



Methods 



To gain information on the time at which fruit injury was initiated in an 
unsprayed block, we placed cloth bags over branch terminals harboring 
developing flower buds to exclude TPB adults for specified time periods. For 
the first 3 years (1981-1983), we used 2 approaches to bagging buds. In the 
first experiment, we employed 280 bags (half on Mcintosh, half on Delicious) at 
silver tip. At each of 6 stages (tight cluster, early pink, late pink, petal 
fall, 1 week after petal fall, 2 weeks after petal fall), we removed 40 bags 
(20 per cultivar), thereby exposing the buds to TPB from time of bag removal 
onward. Check bags remained in place the entire season. In the second 
experiment, no terminals were bagged until tight cluster. At that time and at 
each of the above stages thereafter, we bagged 40 terminals (half on Mcintosh, 
half on Delicious), thereby preventing TPB from causing injury from time of 
bagging onward. Check terminals remained unbagged the entire season. In both 



21 

experiments, all bags were removed from the beginning to the end of bloom to 
permit pollination. For the last 3 years (1984-1986), we conducted a third 
experiment in which we used a single approach to bagging buds. We emplaced 280 
bags before silver tip (half on Mcintosh, half on Delicious). At the start of 
each of 7 bud development stages (silver tip, green tip, half-inch green, tight 
cluster, early pink, late pink, and petal fall) we removed 40 bags (20 per 
cultivar) but replaced the bags at the end of that stage, thereby exposing the 
buds to TPB only during that stage. In addition, 40 check terminals were not 
bagged. As before, all bags were removed during bloom for pollination. In all 
experiments, bagged and check terminals were examined in July or August for TPB 
injury to fruit. 

To acquire information on the abundance of TPB adults in these 
experimental blocks during each tree development stage, each year at silver tip 
we hung 20 sticky-coated, white visual monitoring traps (half on Mcintosh, half 
on Delicious) in trees immediately adjacent to the trees with bags. TPB adults 
were counted and removed from traps at each tree development stage. 
To compare time of fruit injury initiation and time of TPB abundance with time 
of pesticide treatment against TPB, each year in another block adjacent to the 
above we applied pesticide to 8 randomly-positioned trees (all Mcintosh) at 
each of 4 different tree development stages. On each tree, 60 fruit were 
examined in August or September for TPB injury. 



Results 

Over the 6 years in which flower bud terminals were bagged with cloth to 
assess the time at which TPB fruit injury was initiated, 6904 bagged and check 
fruit were examined for injury. Normally, 6 years of research involving nearly 
7000 experimental fruit is sufficient to gain a detailed impression of any 
insect interaction with tree fruit. In this case it was not. The data (Table 
1) reveal inconclusive, even conflicting trends. Thus, the results of 
Experiment 1 (in which terminals were bagged at silver tip and bags were 
removed permanently at successive stages beginning at tight cluster) suggest 
that progressively less injury to fruit was initiated at successive stages 
after tight cluster. Conversely, the results of Experiment 2 (in which 
terminals were bagged permanently at successive stages beginning at tight 
cluster) suggest that progressively greater injury to fruit was initiated at 
successive stages after tight cluster. The results of Experiment 3 (in which 
terminals were bagged permanently except during a given developmental stage) 
suggest lack of a consistent trend in time at which injury to fruit was 
initiated . 

The visual trap capture data (Table 2) suggest TPB adults were on average 
most abundant in the unsprayed experimental block from half-inch-green until 
late pink. Comparatively few were captured before half-inch-green and after 
pink. Time of peak captures varied considerably from year to year. We should 
add that the consistent decline in trap captures from pink onward may have been 
due only partly to decreasing TPB populations. It may have been due also to 
declining ability of the traps to compete as visual stimuli with developing 
foliage and blossoms. 

The pesticide timing experiments (Table 3) reveal no clear picture of the 
most effective time of treatment for preventing TPB injury to fruit. The only 



22 

Table 1. Percent TPB-injured fruit on terminals bagged with cloth during 
specified tree development stages. Exp. 1 = terminals bagged at silver tip, 
free of bags from designated stage onward. Exp. 2 = terminals covered with 
bags from designated stage onward. Exp. 3 = terminals free of bags only during 
designated stage. 

% Injured fruit 

Year Exp. ST GT HIG TC EP LP PF 1 WK 2 WK CK 



Bags removed from this growth stage onward 



1981 1 

1982 1 

1983 1 



27.4 


13.2 


15.2 


9.7 


10.9 


5.5 


4.6 


8.7 


7.3 


5.3 











1.7 


4.5 


6.8 











2.6 


1.5 


13.5 


9.1 


6.8 


3.2 


3.6 


2.7 


2.6 


243 


221 


232 


237 


214 


228 


216 



Average — 

Total No. Fruit — 

Injury as % of 

TC Injury -- ~ ~ 100 67 50 23 27 20 19 



Bags put on at this growth stage 



1981 2 

1982 2 

1983 2 



6.9 


5.2 


— 


12.5 


17.2 


10.5 


12.3 


5.9 


3.9 


3.9 


2.4 


6.5 


10.1 


10.4 


1.1 


6.5 


6.1 


3.3 


7.4 


3.8 


11.6 


4.6 


5.2 


5.0 


6.1 


10.4 


8.1 


11.4 


314 


318 


243 


344 


323 


461 


709 



Average — 

Total No. Fruit — 

Injury as % of 

CK Injury — ~ ~ 40 46 44 54 91 71 100 

Growth stage during which terminals were exposed 



1984 3 







1.0 





1.3 


1.8 


2.2 


1.0 


— 


— 


5.0 


1985 3 




1.5 


2.4 


7.4 


1.8 





9.8 


6.6 


— 


— 


10.0 


1986 3 







1.0 


2.2 








1.3 





"""" 


" 


4.3 


Average 




0.5 


1.5 


3.2 


1.0 


0.6 


4.4 


2.5 








6.4 


Tot. No. Fruit 


335 


332 


247 


305 


325 


384 


369 


— 


— 


304 


Injury as % 


of 






















CK Injury 




8 


23 


50 


16 


9 


69 


39 






100 



Legend: ST=silver tip; GT=green tip; HIG=half-inch green; TC=tight cluster; 
EP=early pink; LP=late pink; PF=petal fall; 1 WK=1 week after PF; 2 WK=2 weeks 
after PF; CK=check. 



23 

Table 2. Capture of TPB adults on 20 visual monitoring traps at successive 
stages of tree development. Traps were emplaced at silver tip and removed 2 
weeks after petal fall. 

Average no. adults captured per trap 



Year 


GT 


HIG 


TC 


EP 


LP 


PF 


2 WK 


1981 


1.5 





3.7 


__ 


5.4 


2.6 


1.4 


1982 


2.4 





2.8 





5.6 


1.0 


0.4 


1983 


2.6 


— "~ 


10.8 





0.8 


0.4 


0.4 


Average 


2.2 


__ 


5.8 


__ 


3.9 


1.3 


0.7 


(1981-83) 
















1984 





0.9 


0.4 


5.0 


0.7 





.. 


1985 





1.4 


1.7 


2.0 


0.8 


0.5 





1986 





0.4 


0.4 


0.4 


0.4 


0.1 


— *" 


Average 





0.9 


0.8 


2.5 


0.6 


0.2 


__ 


(1984-86) 

















Table 3. Injury to fruit by TPB adults on trees treated with pesticide at 
different times. 



% Injured fruit when pesticide 
applied at 



Year Pesticide HIG TC EP LP PF CK 



2.3 


0.3 


1.6 


3.6 


5.6 


2.6 


4.3 


2.8 


4.4 


5.9 


3.0 


3.8 


5.3 


7.0 


5.2 



1981 Ambush" 2EC (6.4 oz/100) 

1982 Ambush'" 2EC (6.4 oz/100) 

1983 Ambush" 2EC (6.4 oz/100) 



Average (1981-1983) 2.6 2.8 3.2 5.0 5.6 

1984 Pydrin" 2.4EC (3.5 oz/100) 0.6 0.8 0.4 0.6 — 1.3 

1985 Pydrin" 2.4EC (3.5 oz/100) 0.6 1.3 0.8 1.3 — 0.4 

1986 Cygon" 50EC (16 oz/100) 0.6 1.3 0.6 0.8 — 1.3 



Average (1984-1986) 0.6 1.1 0.6 0.9 — 1.0 



24 

consistent trend was that holding off treatment until petal fall resulted in 
very little reduction in injury. Even so, the best treatments (tight cluster 
during 1981-1983 and half-inch-green or early pink during 1984-1986) reduced 
fruit injury by only about 50% compared with unsprayed check trees. This 
situation was true even though the pesticides used (Ambush", Pydrin", or 
Cygon") were among the most effective known against TPB. 

Conclusions 

We conclude that conducting research on the time of initiation of TPB 
injury to fruit in apple orchards and the time at which it is most efficacious 
to apply pesticide for TPB control is no less frustrating than attempting to 
manage TPB effectively in commercial orchards. Examination of 11 years of 
pesticide trial data of numerous researchers in the eastern United States and 
Canada reveals a truly incredible amount of variation from locale to locale and 
from year to year within a locale in the effectiveness of any given material in 
preventing TPB fruit injury. Our 11 years of sampling fruit at harvest in 
commercial orchards throughout Massachusetts reveals an equally large variation 
in TPB injury and in success at controlling TPB. The data presented here on 
tests conducted in the same experimental orchard over 6 consecutive years 
likewise are fraught with a high degree of variation, the causes of which are 
uncertain. In fact, the picture we now have of how to control TPB effectively 
is nearly as unclear as when we began these tests in 1981. It seems to us no 
wonder, therefore, that growers have a difficult time dealing with the insect. 

If we can conclude anything from the research reported here and from 
observations we and others have made in commercial orchards, it is this. 
First, initiation of TPB fruit injury may occur any time from tight cluster 
through petal fall. Second, populations of TPB in commercial orchards may be 
sufficiently great at any time from tight cluster to petal fall to cause 
considerable fruit injury. Third, visual monitoring traps have proven over the 
years to be sensitive in determining if TPB populations are sufficiently great 
to merit possible pesticide application. Fourth, materials such as Cygon" and 
pyrethroids are probably the most effective sorts of materials against TPB, 
though their use in no way guarantees good control. Finally, if used, 
pesticide should be applied against TPB sometime between half-inch-green and 
late pink. But, based on the data reported here, we would not want to predict 
what the outcome might be. Perhaps, as Rick Weires of the Hudson Valley Lab 
and we have pointed out several times, we should be paying less attention to 
TPB and more attention to factors such as bruising and mechanical injury to 
fruit during harvest and grading. In virtually every Massachusetts orchard we 
and others have sampled over the years, bruising, stem punctures and mechanical 
injury have been responsible for far more culls (average of 29 bushels per acre 
per year) than TPB and all other insects combined (average of 3 bushels per 
acre per year) . 

•k "k rk "k :k 



COOPERATIVF EXTENSION SERVICE 

U S DEPARTMENT OF AGRICULTURE 

UNIVERSITY OF MASSACHUSETTS 
AMHERST MASS 01003 



OFFICIAL BUSINESS 

PENALTY FOR PRIVATE USE, S300 



BULK RATE 


POSTAGE & FEES PAID 


USDA 


PERMIT N.) G?G8 



Fruit Notes 



OCT 20 C7 



Prepared by: Department of Plant and Soil Sciences 

Massachusetts Cooperative Extension, University of Massachusetts, United 
States Department of Agriculture and Massachusetts counties cooperating. 

Editors: W. R. Autio and W. J. Bramlage 



I ' ' ■ ' M C C 



Volume 52, No. 3 
SUMMER ISSUE, 1987 




Table of Contents 



Postharvest Calcium Treatments: Reducing the 
Risk of Fruit Damage 

Establishing a System for Automatic Monitoring 
and Control of CA Storages 

Pomological Paragraph: Use of Liquid-N, 
for O, Pulldown in CA Storages 

Does Summer Pruning of Mcintosh Pay? 

Pomological Paragraph: Scion Cultivar Affects 
Rootstock Shank Rooting 

The Second Stage of Apple IPM in Massachusetts 

Pomological Paragraph: New Mcintosh Strain Discovered 

Integrated Pest Management and Biological Control Potential 
for Strawberries in the Northeastern United States 



SCIENCES LIBRARY 



A New Program for Integrated Pest Management 
of Strawberries in Massachusetts 

Postharvest Handling of Blueberries 



V. 



POSTHARVEST CALCIDM TBEATMEMTS: REDUCIHG THE RISK OF FRUIT DAMAGE 

William J. Bramlage, Sarah A. Weis, and Patricia A. Shesgreen 
Department of Plant and Soil Sciences 
University of Massachusetts 

Recently, we re-examined the potential benefits and risks from using 
postharvest calcium (Ca) treatments ( Proc. Mass. Fruit Growers' Assn. 1986. 
92:106-109). To summarize, if the harvested fruit are low in Ca, they have a 
reduced storage potential. Postharvest dips or drenches with calcium chloride 
(CaCl2) can significantly improve fruit Ca levels and storage potential. 
However, CaCl2 dips or drenches can cause spotting of fruit, usually seen as 
small, black, sunken areas on the cheeks of the fruit or bronzing at the calyx 
end, which may be serious enough to downgrade the fruit. Our earlier 
recommendation of 21 lbs of CaCl2 per 100 gallons of water [ Fruit Notes 
48(4): 18-19] was excessive and led to an unacceptable amount of spotting. More 
recently we have suggested 12 lbs of CaCl2 per 100 gallons of water. This 
amount is sufficient to significantly improve fruit Ca levels and potential 
storage life, yet greatly reduces the risk of fruit spotting. 

During the past several years we have conducted a series of tests to try 
to identify factors contributing to the amount of fruit spotting resulting from 
postharvest CaCl2 treatments. Here we report the results of these tests. 

Time in solution : Most Ca that enters fruit from a conventional 
postharvest treatment is taken in slowly over time from a residue. Thus, time 
in solution is not a factor for Ca uptake as long as fruit are covered by 
solution and a residue is established. In our tests we routinely dip fruit for 
20 seconds for uniformity, but a shorter time would be sufficient; there is no 
benefit from a longer period. There is some direct entry of solution into the 
fruit through openings in the skin surface. These include the calyx canal, 
lenticels, and wounds, even ones not visibly apparent. All of these entry 
sites are variable among cultivars, handling practices, and growing conditions. 

Relative temperatures of fruit and water . Dips and drenches normally 
employ cold water. However, fruit temperature can vary greatly. Our early 
tests showed that the wanner the apple was at time of dipping, the more Ca it 
absorbed. To determine the role of fruit temperature in spotting, we dipped 
70°F Mcintosh and compared them with fruit first cooled to 320F. The solu- 
tion was initially 50°F, but it either warmed or cooled during treatments, 
depending on temperature of the apples. The warm fruit developed much more 
spotting than did the cold fruit. The reason for this is probably that when a 
warm fruit is plunged into cold water, the air inside the fruit quickly cools 
and occupies less volume. This situation creates a partial vacuum that draws 
solution into the apple through any openings in the fruit surface. Cells 
around these openings are suddenly in contact with a high CaCl2 concentration 
and they can be damaged, eventually dying and producing spots. Therefore, if 
warm fruit are treated with a CaCl2 solution, a lower rate of CaCl2 may be 
needed to avoid spotting. The better approach probably is to cool the fruit at 
least partially before treatment or to ensure that the treating solution is at 
a temperature fairly near that of the fruit. 



Fruit maturity . The characteristics of a fruit surface may change during 
maturation. Thus, fruit maturity might affect solution uptake and development 
of spots after storage. We harvested Mcintosh early-, mid-, and late-season 
(at 1-week intervals) from the same trees and dipped them in a series of CaCl2 
solutions with and without diphenylamine (DPA) . Fruit maturity had no effect 
on the amount of fruit spotting resulting from these treatments. Thus, 
maturity does not appear to be a significant factor in development of spotting. 

Addition of DPA . DPA increases Ca uptake from a solution when combined 
with CaCl2, as is normally recommended. Why this occurs has not been 
established. To find out if DPA increased spotting from Ca treatments we 
compared two different CaCl2 concentrations, with and without DPA. We found 
that DPA tripled the amount of spotting resulting from a given CaCl2 
concentration. We also found that DPA alone caused significant spotting on 
Mcintosh, especially around the calyx area. Why DPA increases spotting is 
unclear. We tried two different formulations of DPA and got equivalent amounts 
of spotting, with and without CaCl2. The recommended rate of CaCl2 use for 
postharvest treatments may have to vary, depending on whether or not DPA is 
included in the mixture. It should be noted that a number of fruit that were 
treated with neither CaCl2 nor DPA developed some spotting after storage, 
apparently as a result of latent damage to cells caused by orchard applications 
of pesticides. (These trees had not been sprayed with foliar CaCl2.) Clearly, 
not all spotting of fruit after storage is attributable to CaCl2 or DPA. 

To follow up on these findings, in 1985-86 we conducted a large test in 
which we dipped Mcintosh in solutions containing 4, 8, 12, or 16 lbs of CaCl2 
per 100 gallons plus DPA, a surfactant, or neither of these materials. After 
storage we measured both the increase of Ca in the fruit and the amount of 
fruit spotting. As expected, both Ca uptake and fruit spotting increased in a 
straight line as the concentration of CaCl2 in the dip solution increased. The 
presence of DPA in the dipping solution did not increase the amount of Ca in 
the fruit at the end of storage, but it increased the amount of spotting. Use 
of the surfactant also had no effect on the final amount of Ca in the fruit, 
but increased the amount of spotting, though to a lesser extent than did DPA. 

Washing fruit after dipping . A report from Australia stated that treated 
apples could be washed 3 days after dipping or drenching; the wash reduced 
spotting but not total Ca uptake. To test this approach, we dipped Mcintosh in 
12 lbs of CaCl2 per 100 gallons, washed them 1, 3, or 7 days after dipping, and 
measured Ca uptake and spotting at the end of storage as compared with similar 
samples that had not been washed. Washing 1 or 3 days after dipping greatly 
reduced Ca uptake, while washing 7 days after dipping produced less of a 
reduction. In this experiment CaCl2 did not increase spotting, whether or not 
the fruit were washed. It appears that even if washing controlled spotting, 
washing 3 days or less after dipping would nearly eliminate any benefit from 
treating with CaCl2. Furthermore, the logistics of washing after dipping could 
make this approach prohibitively time-consuming under our storage systems. 

Interaction with iron . At a meeting last summer, a colleague from 
Australia said that the cause of spotting was actually iron, which was 
extracted from metal and put into solution by the CaCl2. At the same meeting, 
a report from New Jersey indicated that presence of iron in water was the cause 
of damage to peaches following hydrocooling. Thus, we conducted an experiment 
to test the possible role of iron in apple spotting. 



We set up solutions containing different concentrations of iron, with and 
without CaCl2. Iron caused severe spotting, and when it was combined with 
CaCl2 the spotting was increased. We also prepared CaCl2 solutions, 12 lbs per 
100 gallons, in a plastic bucket and in a rusty metal bucket. The CaCl2 
solution in a plastic bucket caused no fruit spotting, but the one in the metal 
bucket caused substantial spotting. Our purpose in this test was simply to 
find out if this avenue might lead anywhere, and it is obvious that it merits 
further study. It is also noteworthy that in the washing experiment, described 
above, we had no spotting from 12 lbs of CaCl2 per 100 gallons in 1986-87, 
whereas in previous years spotting occurred. The dipping tank used in these 
tests is made of galvanized iron and after years of use was starting to rust. 
Last summer it was painted, and so the CaCl2 solution in 1986 was no longer in 
direct contact with iron. Further tests must be made to establish the 
importance of iron in this problem but the implications are consistent with the 
comments of our Australian colleague, who said that eliminating metal tanks 
solved their spotting problem. 

In conclusion, it must be reaffirmed that a postharvest treatment with 
CaCl2 can significantly increase storage potential of apples. It appears that 
12 lbs of CaCl2 per 100 gallons of water is a reasonable compromise, increasing 
fruit Ca levels significantly with a relatively small risk of spotting. (Note 
that our assessment of spotting is very intense. Most of our "spotted" fruit 
would still be in grade.) The CaCl^ must be Briner's Grade or purer , since it 
is considered by authorities to be a food additive. The solution must contain 
an appropriate fungicide, or mixture of fungicides, or severe rotting can 
result. DPA or ethoxyquin can be applied with the CaCl2. We suggest adding 1 
pint of vinegar per 100 gallons of solution to protect against possible adverse 
effects of a high pH due to the CaCl2 ( Fruit Notes 50(2) : 18-20) . 

We suspect that spotting results from the solution that enters the fruit 
openings during the dip. Our studies show that spotting is increased when DPA 
or a surfactant is included in the mixture, when the fruit are significantly 
warmer than the solution, or when substantial levels of iron are present in the 
solution. Under these conditions, perhaps the CaCl2 should be reduced to 8 or 
10 lbs per 100 gallons. 

We shall continue with these studies, to try to find conditions under 
which the risk of fruit spotting from postharvest CaCl2 treatments can be 
minimized or eliminated. These treatments have great value in increasing 
storage life potential, and are extremely useful as a final technique when you 
recognize at harvest time that a Ca problem exists. They are used routinely by 
some Massachusetts growers, and are used extensively for apples in many parts 
of the world. Their use should not be ruled out because of a fear of fruit 
damage. However, they must be used with care, just as with any other chemical 
application. 

***** 



ESTABLISHING A SYSTEM FOR AUTOMATIC MONITORING AND 
CONTROL OF A CA STORAGE 

Katrin Kaminsky and William J. Bramlage 
Department of Plant and Soil Science 

and 

Ernest A. Johnson 
Department of Food Engineering 
University of Massachusetts 

The Orsat gas analyzer is used almost exclusively in New England to 
determine the concentrations of oxygen (O2) and carbon dioxide (CO2) within a 
controlled atmosphere (CA) storage. Control of these levels is performed 
manually by the storage operator. Although the Orsat method is inherently 
accurate, the procedure itself for sampling and measuring the atmosphere in the 
rooms contains much opportunity for human error. Also, since this operation is 
time-consuming, atmospheres are generally measured and adjusted no more often 
than once per day. Under this type of management considerable fluctuation of 
the storage atmosphere can occur, and problems can go unnoticed or uncorrected 
for some time. To compensate for these potential problems, significant margins 
of error are incorporated into standard CA recommendations. Even so, serious 
errors in atmosphere maintenance are still common. 

There are alternatives to the Orsat method of measuring storage atmosphere 
composition. Electronic devices for measuring O2 and CO2 are widely available. 
A system using these devices to frequently and automatically measure O2 and CO2 
levels was developed in England, and quickly was expanded to provide automatic 
adjustment of O2 and temperature when they exceeded set tolerance levels. More 
recently, automatic adjustment of CO2 has also been developed. These systems 
are controlled by a programmed computer, and can be purchased as "package" 
units. However, the costs of such units is discouraging for operators of the 
relatively small storages that are typical of the New England apple industry. 

Another alternative is the "user-built" system, in which a user assembles 
his own system from available components, developing a system to meet his needs 
and to stay within his financial resources. Such a system employs separate 
components which are available for O2 and CO2 analysis, a personal computer for 
data handling and initiation of sampling, measuring, and controlling devices, 
and the necessary pump, valves, and relays to facilitate the whole process. 
This approach has been applied successfully to both research and commercial 
systems at a cost less than that of a package system. 

It is our conviction that automatic monitoring and controlling of CA 
storage atmospheres can significantly improve operation of New England apple 
storages. To establish a demonstration, "user-built" system for use with the 
storage rooms at the Horticultural Research Center, Belchertown, last year we 
received a grant from the Massachusetts Society for Promoting Agriculture. 
During the 1986-87 season, we assembled and operated this system. It is the 
purpose of this article to describe the system and provide an initial 
assessment of its operation. 



The Horticultural Research Center contains five storage rooms, four of 
which are normally operated as CA rooms; two rooms have a capacity of 2500 
bushels each and the other two have a capacity of 600 bushels each. 
Previously, temperature has been monitored by a single mercury thermometer 
placed inside the door of each room, and any adjustment of temperatures has 
been done manually. O2 and CO2 were measured daily with a single Orsat 
analyzer, samples being drawn from each room with an electric pump. O2 was 
added as needed by operating a controlled leak in the door, and CO2 was 
scrubbed when necessary using a lime box. O2 pulldown was achieved with a 
liquid-N2 system. 

The system established in 1986 was as follows. Temperature monitoring was 
upgraded by installing multiple thermocouples in each room, following Cornell 
University recommendations (Cornell University Agricultural Engineering 
Extension Bulletin 430). A coimnercially available paramagnetic O2 analyzer and 
a commercially available infrared CO2 analyzer were obtained to replace the 
Orsat analyzer. These electronic measuring devices were supplied with air 
drawn from a room by a new electric pump through the copper sampling lines that 
previously supplied the air for the Orsat. The existing solenoid valves on 
these lines were wired via a relay board to a conventional personal computer. 

A commercially available software package, designed for use in automatic 
monitoring and controlling systems, was set up so that an air sample was drawn 
hourly from each room and passed through the O2 and CO2 monitors. Analyses 
were recorded on both a disc and on a print-out. Also, at each sampling time, 
temperature at one thermocouple in each room was measured and recorded. Later 
in the season a dewpoint indicator was purchased for humidity measurement, and 
subsequently each sample was also measured for relative humidity and these data 
were also recorded. Thus, an hourly record of O2, CO2, temperature, and 
relative humidity within each room was automatically obtained. (The system 
could have been programmed for either more frequent or less frequent sampling 
or recording.) 

The system can be programmed so that adjustments of temperature, O2, and 
CO2 can be made automatically when the measured values exceed previously 
established limits. For example, a temperature of 37°F might be desired and 
the program might change the temperature control setting if it falls below 
36.5°F or rises above 37.5°F. In our first season we continued to control 
temperature manually and to operate the lime box manually. However, O2 control 
was automated. Each room possessed 4-inch PVC inlet and outlet lines fitted 
with large solenoid valves. A cylinder of N2 gas and a squirrel cage fan were 
attached to the inlet manifold. The system was programmed so that when an O2 
reading fell below 2.5% or rose above 3.5%, the control system was activated 
via the relay board. This system vented either air or N2 into the room, 
depending on whether O2 was too low or too high. Outlet valves were also 
opened automatically to relieve the positive pressure caused by air or N2 
addition to a room. 

The system worked reasonably smoothly, given that this was its first year 
of operation and we were developing it as time and availability of supplies 
permitted. During the summer we shall complete some unfinished wiring and 
plumbing, and we anticipate that we shall go into the 1987-88 season with a 
completed system and with the operators now being familiar with the operation 
and the equipment. The operators had little previous experience with computer 



operation. 

A detailed assessment of the operation of this system versus that of an 
Orsat-monitored system will be published later. However, an obvious benefit 
was the time-saving achieved by automatic monitoring of atmospheric conditions 
in the CA rooms. This savings was especially appreciated during the initial 
pull-down period. At this time, the hourly program was deactivated and a 
continuous O2 reading was taken for the room being flushed with liquid-N2. 
This allowed the operators to watch the changes in O2 level as the liquid-N2 
was metered into the room. 

Total cost of the equipment was approximately $8500. However, the 
dewpoint indicator cost $1300 and was included in our system for research 
purposes. Likewise, our system has greater control capability built into it 
than a commercial operator might desire, since we may wish to completely 
automate controls for research purposes. 

The establishment of this system has created the opportunity for us to 
demonstrate the feasibility and advantages of automatic CA operation. This is 
neither a new idea nor new technology. Similar — and often more sophisticated — 
systems are in commercial use in many parts of the world. Our objective in 
this project is to lead the way in upgrading New England storage operations to 
the level of many of the area's competitors, and through better storage 
operation to provide a higher quality apple for the market. 

***** 



PCMOLOGICAL PARAGRAPH 

Use of Liquid-N2 for O2 Pulldown in CA Storages 

William J. Bramlage 

Department of Plant and Soil Sciences 

University of Massachusetts 

During the past two years a number of New England CA storage operators 
have used liquid-N2 for O2 pulldown. At the Horticultural Research Center, 
Belchertown, we have used this system and have been very pleased with the 
results (Proc. Mass. Fruit Growers' Assoc. 92:102-105). Dr. James A. Bartsch 
of the Department of Agricultural Engineering, Cornell University, recently 
published a factsheet entitled, "Creating a Low Oxygen Atmosphere with Liquid 
Nitrogen." This information should be of interest and value to anyone using 
this system or considering use of it. The factsheet "Agricultural Engineering 
Facts, EF-9" can be obtained from William J. Bramlage, Department of Plant and 
Soil Sciences, French Hall, University of Massachusetts, Amherst, MA 01003. 

***** 



7 

DOES SUMMER PRUNING OF MCINTOSH PAY? 

Duane W. Greene, Wesley R. Autio, and William J. Bramlage 

Department of Plant and Soil Sciences 

University of Massachusetts 

The uncertainties about the future of Alar* and the possibilities of 
adverse results on animal feeding studies led many growers in 1986 to use no 
Alar* or a reduced amount of Alar* last year. A number of suggestions were 
made last year to help growers cope with reduced Alar* use, and summer pruning 
was listed as one of the procedures available to growers to help alleviate 
problems associated with the nonuse of Alar*. Last year a summer pruning 
experiment was conducted at the Horticultural Research Center using mature 
Mcintosh trees. The results of this experiment are reported here. 

There is a direct relationship between the amount of light a fruit 
receives and red color development. Fruit that are exposed to direct or near 
direct sunlight will develop red color early and the intensity of the color 
will be great enough so that these fruit can be harvested as U.S. Extra Fancy. 
Alar* has been indispensible to growers in controlling drop and retarding 
ripening until fruit develop sufficient red color to be sold as U. S. Extra 
Fancy. In the absence of Alar* fruit may fall to the ground before they 
develop sufficient red color. If light penetration into the tree can be 
increased by appropriate pruning techniques, fruit may develop red color early. 
This early coloring would do two things. First, it would allow early harvest 
of fruit that would have the potential for long-term storage. Secondly, it 
would allow the harvest of a larger percentage of the crop as hand picked fruit 
rather than as drops. 

A block of mature Mcintosh on M. 7 rootstock that received no Alar* in 
1986 was selected, the summer pruning treatments were randomized, then half of 
the trees were summer pruned during the 3^*^ week in August. Only 1-year-old 
wood and unproductive wood were removed. It required about 25 minutes for one 
person to summer prune each tree. The first harvest on these trees was on 
September 10. 

Large cuts, particularly in the tops of trees, should not be made during 
the summer. Falling branches, heavy with leaves and developing fruit, can 
severely bruise fruit below. For summer pruning to be truly effective, large 
thinning-out cuts must be made during the dormant period. These cuts will open 
up a tree. The summer pruning further increases light penetration by removing 
some of the current season's growth and unproductive wood. 

There were many positive effects following summer pruning (Table 1). 
Fruit on summer pruned trees had more red color, considerably more of them 
graded U. S. Extra Fancy, and a much larger percentage of the crop was 
harvested during the first picking (September 10). Because a larger percent of 
the crop was harvested the first time, there were fewer drops and more hand- 
picked fruit from the summer-pruned trees. Summer pruning did not influence 
the total yield on these trees. However, approximately 2 more bushels of fruit 
per tree were harvested as hand picks rather than as drops. 



Table 1. Effects of summer pruning on Mcintosh fruit. 



Parameter 



Summer pruned 



Not summer pruned 



Change (%) 



Red color (%) 57 

U. S. Extra Fancy (%) 72 

Crop harvested l^t pick (%) 79 

Crop harvested by hand (%) 81 

Drop (%) 19 

Dormant pruning time (min/tree) 11 



49 
42 
59 
70 
30 
17 



+ 16 
+ 71 
+34 
+ 16 
-37 
-40 



Did summer pruning pay? Let us assume a price of $1.60 per bushel for 
drops and $8.00 per bushel of hand picks. There were 144 more bushels of hand- 
picks per acre from summer-pruned trees with an additional return of $932.00. 
It would take a pruner about 30 hours per acre to do a good summer pruning job 
on these trees. Unless a grower pays his workers $31.00 or more per hour, 
summer pruning more than paid for itself. This figure is conservative because 
it required 40 percent less time to prune summer-pruned trees during the 
dormant season, thereby producing additional savings. We feel that summer 
pruning is a procedure that should be part of every grower's maintenance 
program on mature trees, especially if Alar* is not used. 

***** 



POMOLOGICAL PARAGRAPH 

Scion Cultivar Affects Rootstock Shank Rooting 

Wesley R. Autio 

Department of Plant and Soil Sciences 

University of Massachusetts 

Many nurseries bud apple trees on certain rootstocks 12 to 18 inches above 
the soil line. When these trees are planted in the orchard a large portion of 
the originally above-ground rootstock material must be buried. The philosophy 
behind this practice is that rooting along the long, buried shank may improve 
the anchorage of the tree and reduce requirements for staking. However, in 
some cases rooting does not occur and a less stable condition results than if 
the trees were budded at a lower height and planted only slightly deeper than 
they were in the nursery. A reason for this lack of rooting is given by Roy 
Rom and George Moticheck in a study published this year (HortScience 22:57-58). 
They found that the scion cultivar was the major factor affecting rooting along 
the buried rootstock shank. In general, nonspur cultivars resulted in 
significantly more rooting than did spur-types, possibly explaining the poor 
shank rooting which has been observed with some trees. 



***** 



9 

THE SECOND STAGE OF APPLE IPN IN MASSACHUSETTS 

Ronald J. Prokopy 

Department of Entomology 

University of Massachusetts 

Through 1977, most Massachusetts apple growers controlled apple insect 
pests by making insecticide applications every 10 to 14 days, irrespective of 
whether pest insects were present in sufficient abundance to merit such 
treatment. From 1978 through 1982, our College received funds from a 5-year 
federal Cooperative Extension Service grant to initiate a pilot program of 
integrated pest management (IPM) in Massachusetts apple orchards. The 
entomological part of the program had 3 major objectives: to promote the 
buildup of natural populations of beneficial predators; to reduce pesticide 
use; and to maintain or increase the high quality and quantity of fruit 
produced. Our overall entomological approach to achieving these objectives lay 
in intensive, careful monitoring of pest and beneficial, natural enemy 
population abundances in participating IPM orchards, and in advising IPM 
growers of need, optimal timing, and type of pesticide to be applied. 

The results of this pilot program were highly encouraging. In fact, they 
were so encouraging that 2 biologists in the program decided to form a private 
IPM-consult antship business: "New England Fruit Consultants". From 1983 
through 1986, NEFCO has been very active in providing IPM services to a 
substantial number of Massachusetts apple growers. "Boston IPM", though active 
largely in Vermont, has also provided IPM services to a few Massachusetts 
growers. In 1986, about one-third of the apple acreage in Massachusetts was 
serviced by these private consultants. In addition, results of a recent survey 
we conducted [ Fruit Notes 51(2):11-16 and 51(3):19-25] indicate that more than 
two-thirds of Massachusetts apple growers now employ IPM practices. 

To what degree have IPM practices benefited Massachusetts apple growers? 
Table 1 presents a summary of the amount of pesticide used each year in 
Massachusetts IPM apple orchards from 1977 through 1986. 

These results show that compared with pesticide use before the pilot 
program, there was (on average) a 37% reduction in insecticide use and a 61% 
reduction in miticide use during the pilot program (1978-82) and a 43% 
reduction in insecticide use but essentially no change in miticide use in 
orchards serviced by private consultants (1983-86). On average, fruit quality 
in IPM orchards has equalled or exceeded that realized before the start of the 
program. Finally, the growing of "healthier" (less-pesticide-treated) apples 
and the reduced amount of spray drifting from the orchard into the neighboring 
environment has created a favorable public image for IPM growers. It can be 
concluded, therefore, that this first stage of IPM in Massachusetts apple 
orchards has been a success. 

The second stage of apple IPM is aimed at employing new pest control 
methodologies to achieve a further reduction in pesticide use. The first stage 
has relied on intensive monitoring of pest and beneficial predator abundances 
and subsequent judicious application of needed, selective pesticides least 
harmful to predators. In our opinion, this stage has taken us about as far as 
it can in terms of pesticide reduction. The second stage will rely on 



10 
Table 1. Pesticide use in Massachusetts IPM apple orchards, 



Dosage equivalents of 



No. 
orchards 



Year or blocks Insecticide Miticide 



** 



1977 (Before IPM) 16 9.1 1.8 



1978 (IPM pilot prog.) 8 

1979 " " 16 

1980 " " 18 

1981 " " 19 

1982 " " 36 



1983 


(Priv. 


consults . ) 


33 


1984 


II 


II 


36 


1985 


It 


II 


48 


1986 


II 


II 


51 



6.4 


0.9 


6.0 


0.4 


4.8 


0.8 


6.2 


0.4 


5.5 


0.9 


6.0 


1.3 


5.5 


2.0 


5.1 


2.5 


4.6 


1.7 



Dosage equivalent = actual amount of pesticide used divided by amount 

recommended in Pest Control Guide. 

Does not include oil spray against overwintering mite eggs. 

knowledge gained of the behavior and ecology of pests and beneficial predators 
and on employment of behavior-manipulation techniques as a substitute for use 
of most pesticide treatments. 

For the past 6 years (1981-86), one form of this second stage of apple IPM 
has been used at my small (50-tree) orchard of disease-resistant apple trees in 
Conway, MA. The approach has been as follows: (a) application of a pre-bloom 
oil treatment against overwintering San Jose scale and eggs of the European red 
mite; (b) 2 applications of Imidan (one at petal fall and another 10 to 14 days 
later) for control of European apple sawfly, plum curculio, and first- 
generation codling moth; and (c) use of red-sphere visual traps (1 or 2 per 
tree) to capture and thereby control apple maggot fly adults. Table 2 is a 
summary of the average percent (1984-86) of clean and insect-injured fruit on 
the experimental orchard trees compared with several neighboring (200 meters 
away), unsprayed trees. 

This use of only 2 dosage equivalents of insecticide (compared with 5 to 6 
in the average first-stage IPM orchard and 9 in non-IPM orchards) is not the 
only benefit realized. The absence of any insecticide use from 10 to 14 days 
after petal fall (early June) through the remainder of the growing season has 
allowed key predators and parasites of mites, aphids, leafhoppers, leafminers, 
and San Jose scale to flourish during summer months. The result has been no 
need to make any application of miticide or other pesticide for control of 
these secondary pests. In our opinion, this result strongly suggests that the 



11 

Table 2. Percent clean and insect-injured fruit from experimental and 
unsprayed apple trees. 

Experimental Neighboring 

orchard trees unsprayed trees 

Percent clean fruit 93.7 

Percent injury by: 

Plant bug 1.6 2.7 

Sawfly 0.6 8.7 

Curculio 3.5 96.0 

Codling moth 0.5 58.0 

Leafrollers 0.3 13.7 

Apple maggot 0.2 82.3 

Other 2.3 



problems experienced even in IPM orchards with outbreaks of mites and other 
secondary pests are due in substantial part to detrimental effects on 
beneficial predators and parasites as a result of insecticide, fungicide or 
herbicide applications (even judicious use of selective materials) from June 
onward. 

Can this approach used in the Conway experimental orchard be transferred 
directly and successfully to larger commercial orchards? We doubt that it can 
because of the amount and cost of labor that would be required to place and 
maintain apple maggot traps in every apple tree. But variants of this approach 
that are derived from knowledge we and others have gained of the behavior of 
key apple pests over the past decade could prove successful. Thus, our recent 
research on the host-finding behavior of sawfly, plum curculio, and apple 
maggot adults has suggested that individuals entering an orchard from unsprayed 
trees in nearby woods or hedgerows are most likely to visit first those apple 
trees that are at the perimeter of the orchard and then gradually move into 
interior trees. Because sawfly, plum curculio, and apple maggot populations, 
as well as populations of every other key pest attacking apple fruit, originate 
almost exclusively on unsprayed trees outside the orchard, intercepting these 
insects at the perimeter of the orchard with traps (or spraying insecticide or 
egg-laying deterring chemicals on the perimeter trees to prevent immigration 
into the interior of the orchard) could constitute an effective variant of the 
approach used in the Conway experimental orchard and allow us to enter the 
second stage of IPM in Massachusetts apple orchards. 

At present, the only truly effective traps for direct control of a key 
apple pest are traps for capturing apple maggot flies. Visual traps developed 
for plant bug, sawfly, and leafminer adults are effective for monitoring 
occurrence of adults and are being used extensively in first-stage IPM apple 
orchards, but they have not proven effective as yet for direct control. 
Chemicals that deter egglaying (either pheromones emitted by the adults or 
chemicals emanating from plant tissue wounded by egglaying females) are now 
known, from our recent research, to exist in sawfly, plum curculio, and apple 
maggot. None of these chemicals has yet been identified as to structure or has 



12 

been synthesized. Thus, it will be some time yet before they are available for 
use. Sex pheromones for codling moth and most pest species of orchard 
leafrollers have been identified by Wendell Roelofs and his colleagues at 
Geneva, New York, and have been applied in massive amounts in and around 
experimental apple orchards in an attempt to disrupt mating behavior and 
thereby reduce numbers of larval progeny attacking fruit. But this approach 
will require considerably more work before it is ready for implementation in 
commercial orchards. 

Thus, the picture appears rather bright for behavior-based management of 
many key apple fruit pests in the future. In the meanwhile, it may be possible 
at least to begin the second stage of apple IPM using knowledge and techniques 
presently available. 

Toward this end, we have received support from the Massachusetts Society 
for Promoting Agriculture to carry out a 3-year experiment in several 
commercial apple orchard blocks in which (a) all insecticide and miticide 
spraying of the interior of each block would cease at the end of May (following 
1 pre-bloom and 1 or 2 post-bloom treatments), and (b) the perimeter of each 
block would be managed in such a way as to prevent immigration of key apple 
pests into the interior from June until harvest. The perimeter management 
techniques would be either (a) placement of sticky-coated, apple-odor-baited 
red sphere traps for apple maggot flies in perimeter trees or adjacent woods, 
or (b) application of insecticide to perimeter apple trees every 2 weeks from 
June until harvest. 

We realize this experiment of extreme reduction in insecticide use 
involves high risk of some amount of insect injury to the fruit. At the same 
time, we believe that if we do not venture forward into the unknown, we have 
little chance of moving beyond present pest management practices. 

***** 



P(»10L0GICAL PARAGRAPH 

New Mcintosh Strain Discovered 

Wesley R. Autio 

Department of Plant and Soil Sciences 

University of Massachusetts 

A new Mcintosh strain (EG506 — Adams County Nursery) has been discovered in 
the Hudson Valley of New York which is reported to ripen later than normal and 
to hold on the tree for a longer period of time. We will be establishing a 
planting of these trees in 1988 and will compare them with standard strains of 
Mcintosh. If this strain acts as reported then it may be of great value in 
expanding the Mcintosh harvest season. 

***** 



13 

INTEGBATED PEST MANAGEMENT AND BIOLOGICAL CONTROL POTENTIAL 
FOR STRAWBERRIES IN THE NORTHEASTERN UNITED STATES 

David T. Handley 
University of Maine 

Strawberry producers in the northeastern United States are faced with a 
number of arthropod pests with which they must compete in order to produce a 
profitable crop. Applications of chemical pesticides has been the standard 
method of control for many years, but is now being re-evaluated in view of 
increasing costs, environmental contamination, the development of insect and 
mite resistance, and the disruption of natural enemy complexes. Integrated 
pest management (IPM) programs, developed for many major agricultural crops, 
can improve pest control efficiency by exploiting all possible means of 
management, including cultural, biological, and chemical, resorting to the 
latter only when nonchemical methods cannot maintain pest populations below a 
specific economic injury level. IPM may hold potential for strawberries grown 
in the Northeast, but alternatives and supplements to chemical pesticides are 
presently few. 

Cultural control techniques for strawberry pests include sanitation, e.g. 
removing dead plant material and weeds that may harbor pests, adjusting 
planting times or patterns to avoid peak pest populations, crop rotation, trap 
crops, and mechanical control, such as burning or flooding. Strawberry 
production has incorporated some cultural control measures into the general 
management scheme, such as rotation with other crops that do not share the same 
pest complex, and renovation, during which disease-infected foliage and insect 
overwintering sites are destroyed or tilled into the soil. The time of plowing 
under old beds can affect the status of overwintering pests species. The use 
of trap crops has received little attention for strawberry pests, but may offer 
a means of reducing early outbreaks of some insects (9). Physical barriers are 
effective against some insects, but generally have been considered too 
expensive or labor intensive to be used (4). However, the recent introduction 
of lightweight, synthetic row covers and application machinery may stimulate a 
re-evaluation of this technique. Strawberry plant resistance to certain pest 
species such as root weevils, aphids, and spider mites has been observed. To 
date, however, this is not thought to provide economic control (1,7,10). 

Biological control refers to the use of natural parasites and predators of 
insect pests to maintain populations below economic thresholds. This technique 
may involve searching out and importing exotic, natural enemies, and/or using 
conservation and augmentation techniques to increase the effectiveness of 
natural enemies, whether native or imported (3). 

Several problems are inherent with the practical application of biological 
control of northeastern strawberry pests. The strawberry plant is native to 
the northeastern U.S. The wild strawberry, Fragaria virginiana , is thought to 
be a parent of the now popular cultivated strawberry, Fragaria ananassa (2). 
Therefore, a native pest complex exists that is both established and well 
adapted. This situation greatly reduces the probability of finding effective 
exotic natural enemies. In nearly every successful example of control using 
exotic natural enemies, the pest itself was exotic. Furthermore, success with 
exotic natural enemies usually occurs in salubrious, stable, and undisturbed 



14 

environments (3), none of which are characteristic of northeastern strawberry 
plantings . 

Utilizing conservation techniques for native natural enemies could prove 
more rewarding. Chief among these would be the reduction of nonselective or 
broad-spectrum pesticide use. Despite their effectiveness on a given pest 
species, these materials can destroy natural enemy populations, initiating a 
resurgence and possible population explosion for certain pests, including some 
not previously considered economically damaging. 

The effectiveness of native natural enemies is hampered by other problems 
as well. Due to long coevolut ionary relationships, pest species likely 
developed resistance mechanisms to most parasites, and the parasites themselves 
may be plagued with hyperparasites . Native predators may provide some control 
of strawberry pests. The root feeding larvae of weevils and scarabs are 
attacked by birds and rodents, but these may themselves damage plants. 
Predatory beetles also feed on pest larvae, tarnished plant bugs, and mites 
(9). These predators are relatively nonspecific feeders, however, and are 
thus less effective as control agents of a specific pest. Because they are 
native, they will also have their own natural enemies, which will keep their 
populations, and hence control potential, in check. 

Augmentation of natural enemies, whether native or imported, involves 
manipulation of the population such that control of the pest species is 
improved. Typically, this is accomplished by rearing natural enemies 
artificially and releasing them, either inundatively or as an inoculative 
population (3). Such approaches are usually quite expensive and may not be 
justifiable on a minor crop such as strawberries. 

One of the most important barriers facing biological control potential in 
strawberries is the relatively high value of the crop. Very small amounts of 
damage may have significant economic effects due to the high cash return of 
strawberry fruit. Therefore, when an economic injury threshold is determined, 
it will be quite low, meaning only small pest populations need be present to 
justify control measures (9). These thresholds may require pest numbers to be 
below a level required for the natural predators to remain viable. This 
condition would necessitate supplementary chemical applications, probably 
causing greater harm to the natural enemies, or repeated inundative releases of 
the natural enemy, much like a "biological insecticide". 

Perhaps the most promising use of biological control in strawberries to 
date is against phytophagous mites. In California, cyclamen mite has been 
effectively controlled with Typhlodromus species. These native predatory mites 
can provide adequate control without manipulation, but typically not until the 
third year of a planting. To achieve control in first and second year beds, 
the predator must be stocked. Research also suggests that stocking young 
fields with cyclamen mite along with Typhlodromus could improve establishment 
and effectiveness of the predator (6). Strawberry growers were not receptive 
to this idea, and have since adopted an annual system of production which 
eliminates the need for such controls. Strawberry plantings in the Northeast 
are still maintained for several years, however, allowing cyclamen mite 
populations to reach damaging levels. Although it is unlikely that the 
predatory Typhlodromus could successfully overwinter, inundative releases of 
the predator at specific pest population thresholds potentially could bring 



15 

about substantial control. 

Successful control of the twospotted spider mite has also been achieved 
with a predator. Releases of the mite Phytoseiulus persimilis before spider 
mite populations attained an average of one mite per leaf provided effective 
control in California (8). This predatory mite has also been used successfully 
in greenhouses and under row covers (5). Control is temporary as the mite 
completely eradicates its prey and therefore its food source under these 
conditions. Similar to the Typhlodromus species, P. persimilis would not 
likely survive the climate extremes of the Northeast. This would necessitate 
annual releases of the predator, and the cost required may be prohibitive. 

Despite inherent difficulties, biological control has some potential as a 
component of an integrated pest management program for strawberries in the 
northeastern United States. Research is needed to determine the effectiveness 
of native natural enemies and the existence of exotic species. The strawberry 
root weevil for example, is thought to have come originally from Europe, yet no 
efforts have been reported to seek natural enemies there. Some strawberry 
pests, including leaf rollers and aphids, are already known to be controlled 
effectively by natural enemies (9). Only minor manipulation or alterations 
may be required to bring about much greater biological control of other 
species. 

The increased exploitation of biological control agents, combined with 
proper cultural practices and improved application strategies for chemicals, 
could greatly increase pest control efficiency in strawberries and hence, 
profitability. In addition, such an integrated proeram likely would reduce the 
amount of pesticides used, and thereby reduce the potential hazards of frequent 
and repetitive pesticide use. 

References 

1. Barritt, B.H. and C.H. Shanks. 1980. Breeding strawberries for 
resistance to the aphids Chaetosiphon fragaefolii and C. thomasi . 
HortScience 15:823-825. 

2. Darrow, CM, 1962. The strawberry. Holt, Rhinehart and Winston. New 
York. 447 pp. 

3. DeBach, P. 1974. Biological control by natural enemies. Cambridge 
University Press. London. 323 pp. 

4. Downes, W. 1931. The strawberry root weevil. Can. Dept. Agric. Pamphlet 
no. 5. 2nd ed. 

5. Gould, H.J. and J. Vernon. 1978. Biological control of Tetranychus 
urt icae (Koch) on protected strawberries using Phytoseiulus persimilis 
Athais-Henroit. Plant Path. 27: 136-139. 

6. Huffaker, C.B. and C.E. Kennett. 1956. Predation and cyclamen mite 
populations on strawberries in California. Hilgardia 26(4): 191-222. 

7. Kishaba, A.N., V. Voth, A.F. Howland, R.S. Bringhurst, and H.H. Toba. 
1972. Twospotted spider mite resistance in California strawberries. J. 



16 

Econ. Entomol. 65: 117-119. 

8. Oatman, E.R., J. A. McMurtry, and V. Voth. 1968. Suppression of 
twospotted spider mite on strawberry with mass releases of Phytoseiulus 
persimilis . J. Econ. Entomol. 61: 1517-1521. 

9. Schaefers, G.A. 1981. Pest management systems for strawberries. pp. 
377-393. In: Handbook of pest management in agriculture. D. Pimentel, 
ed. CRC Press. Boca Raton, Fla. 501 pp. 

10. Shanks, C.H., D.L. Chase, and J.D. Chamberlain. 1984. Resistance of 
clones of wild strawberry, Fragaria chiloensis , to adult Otiorynchus 
sulcatus and 0. ovatus . Environ. Entomol. 13:1042-1045. 

•k i< -k -k -k 



A NEW PROGRAM FOR INTEGRATED PEST MANAGEMENT OF STRAWBERRIES 

IN MASSACHUSETTS 

Daniel R. Cooley, Karen Hauschild, and Sonia Schloemann 
University of Massachusetts 

Last fall, -an integrated pest management program for strawberries was 
funded by the University of Massachusetts Integrated Pest Management (IPM) 
program. This article is intended to give a brief outline of the proposed 
program, and invite comments from interested parties. 

Strawberries offer a unique opportunity for integrated pest management, 
for a number of reasons. Note that strawberries suffer important damage from 
all pests: diseases, weeds, and insects. We intend to use the term pest in its 
broadest sense, encompassing any agent which necessitates pesticide 
applications . 

In assessing the potential for strawberry IPM, we saw that while acreage 
on a given farm is not generally large, the number of small farms producing 
strawberries has steadily increased in recent years. As a result, there are a 
number of new strawberry growers in the state. In addition, strawberries 
require relatively frequent applications of pesticides in order to produce 
well. This situation is complicated because only a few fungicides are 
registered for use on strawberries, and the future utility of these compounds 
is threatened because registration may be removed, fungus resistance has 
developed, some of the pesticides used on strawberries are potential 
groundwater contaminants, and some may affect non-target beneficial insects. 
Also, strawberry growers frequently sell their crop to "pick-your-own" 
customers, giving the public exposure to not just the product, but the fields 
in which it is grown. And finally, many strawberry pests have also been studied 
in recent years, either on strawberry or as pests of other crops. The general 
biology and suggestions for innovative management strategies for these pests 
have been developed, but have not been applied generally to commercial 
strawberry production. Massachusetts is in a strong position to use this 
knowledge since the three regional fruit agents all have an active interest and 
good backgrounds in small fruit. 



17 

A few years ago, experience in developing and publishing the New England 
Guide for Managing Diseases and Insects of Small Fruits (3) showed that there 
was not a great deal of current knowledge on strawberry pest control. However, 
a recent survey (5) has identified the most important pathogens. Several fungi 
contributed to berry rots, and several other fungi contributed to root rots. 
The most significant fruit pathogens (and the diseases they cause) were 
Botrytis cinerea (grey mold), Phytophthora cactorum (leather rot), Haines ia 
lytheri (tan brown rot), and Phomopsis obscurans (berry blight). The etiology 
of each of these pathogens is distinct, but in general wet weather and 
increasing fruit maturity cause more disease development. In unmanaged 
situations, fruit rots can destroy the entire crop. Even using recommended 
controls, adverse conditions can cause significant crop loss. For example, 
gray mold causes between 20% and 60% loss in Quebec, depending on weather (4). 
Leather rot losses in Ohio approached 40% in commercial beds in 1980 and 1981 
(6). Gray mold is endemic in strawberry fruit, and Botrytis was frequently 
isolated from all beds in the Massachusetts survey. Leather rot was also 
frequently observed. 

The most damaging strawberry insect and weed pests in Massachusetts have 
not been determined. According to growers, the most important insect pests are 
tarnished plant bug ( Lygus lineolaris ), strawberry bud weevil or clipper 
( Anthonomus signatus ), white grubs ( Phyllophaga spp.), and strawberry root 
weevil ( Otiorhyncus ovatus ). There is little doubt that tarnished plant bug is 
the major contributor to misshapen strawberries (8). 

Several weeds cause economic problems in strawberries, including several 
grass species, Galinsoga, and thistle. Though growers cite these as the 
problem weeds, it is not clear whether this is the case, and if so, how much 
damage is caused. However, it is clear that weeds are a major factor causing 
beds to be taken out of production. 

Previous work supplies some tools to start an IPM program. Gray mold 
epidemiology is partially understood. One study has shown that floral and 
pedicel infections early in the season are more important to future berry 
infections than direct infections occurring at or near harvest (7). A few 
applications of a fungicide early in the season may be as effective as a series 
of applications from bloom through harvest. Such applications could be made 
more efficient by applying epidemiological data from Quebec which indicate that 
temperatures from 15 to 20°C and relative humidities from 90 to 100% for at 
least 28 hrs . are optimal for gray mold epidemics (4). An experimental model 
for gray mold pressure is in the process of being published (1). A similar 
model of temperature and moisture effects on leather rot infection has been 
published recently (6). 

Another element in a fruit rot control program would involve studying 
fungicide retention and redistribution. Presently, growers often apply 
fungicides every 3 to 5 days around harvest if weather is wet, on the 
assumption that this will increase protection against berry rots. On apples, 
captan remains effective for 1 week regardless of rain (9). Frequent 
applications of fungicide around strawberry harvest may be useless. 

Insect monitoring would be a key element in the program. Initial work 
indicates that tarnished plant bug traps similar to those used in apple IPM (2) 
could be successful in strawberry. One technique, using non-visual traps, has 



18 

suggested an economic threshold level of 1 nymph per 25 flower clusters, which 
would provide a starting point for insect monitoring techniques (8). 

Techniques for reducing herbicide use remain poorly developed in all 
crops. To date, there has not been even a survey of the major weed species 
affecting strawberry beds, though a survey is planned for this year. It may be 
possible to reduce herbicide use in new plantings by using a dieback cover crop 
during the previous season. Spot treatments rather than broadcast treatments 
may be an effective way to reduce herbicide use post-planting. 

Anecdotal evidence and experience in other IPM programs in the state 
indicate that spray coverage may be one of the most important sources of error 
in pest management. This can be caused by inaccurate calibration, or by 
inappropriate equipment and calculations. Such problems could be examined 
immediately. 

At the outset, we have proposed a number of specific objectives for the 
program. 

1. Use crop development and weather data to time fungicide applications for 
fruit rot control, and compare the results with typical calendar-based 
timing. 

2. Use insect monitoring techniques on three major strawberry pests, 
tarnished plant bug, strawberry bud weevil, and two-spotted mite, in order 
to time pesticide applications on the basis of the presence or absence of 
the pest, and develop information for economic threshold levels. 

3. Determine what weed species are important in strawberries in 
Massachusetts, and determine the efficacy of present control 
recommendat ions . 

4. Test alternative fungicides against fruit rots, develop improved timing 
for fungicide application via epidemiological data, and test alternative 
cultural practices designed to reduce fruit rot. 

5. Examine present sprayer calibration and equipment, and determine whether 
inaccuracies or inappropriate techniques exist. If they do, suggestions 
on how to improve sprayer efficiency and calibration will be made. 

6. Develop appropriate expert system delivery systems for the IPM 
information, using the INFONET electronic mail system to access Regional 
Extension staff and interested growers. 

7. Distribute pest messages on current status of pest problems and crop 
development on a weekly basis prior to and during harvest, and at longer 
intervals as needed thereafter. 

The first year of the program we are concentrating on a survey of current 
pest management practices, and beginning the testing of reduced pesticide 
recommendations. With a limited number of growers in the Connecticut Valley, 
we have established small sections of fields which will be treated as IPM 
plots. These plots will be treated separately from the rest of the grower's 
field. These plots will also be areas where pest pressure is most intensively 



19 

studied. 

For example, this year there are a number of colored traps in place to 
test the effectiveness of various colors in monitoring tarnished plant bug 
populations. Fungicides will be applied according to flowering and berry 
development, while Botrytis (the primary berry rot fungus) will be monitored on 
last year's leaves and the developing flowers and fruit. Similar monitoring 
will be done in non-IPM plots. It will also be possible to test the validity 
of a new gray mold model (1). Weed species and numbers will be evaluated in 
plots, and the herbicide practices of growers will be determined. The 
comparison of pest pressure in IPM and non-IPM plots will allow us to evaluate 
which practices are the most effective with the least pesticide impact. This 
information will define directions for pest management practices which will be 
refined in the following seasons. 

We are at the beginning of the program. At this stage, we welcome the 
comments and advice of any interested people. 

References 

1. Bulger, M. A., L. V. Madden, and M. A. Ellis. 1987. Influence of 
temperature and wetness duration on infection of ripe strawberry fruit by 
Botrytis cinerea . Can. J. Plant Pathol, (in press). 

2. Coli, W. M., T. A. Green, T. A. Hosmer, and R. J. Prokopy. 1985. Use of 
visual traps for monitoring insect pests in the Massachusetts IPM program. 
Agric. Ecosystems Environ. 14:251-265 

3. Cooley, D.R., J. L. Drozdowski, W. J. Manning, C. F. Brodel, and K. 
Hauschild. 1985. Managing diseases and insects on small fruit in New 
England. Massachusetts Cooperative Ext. Publication no. C-164R. 

4. Devaux, A. 1978. Etude epidemiologique de la moissiure grise des fraises 
et essais de lutte. Phytoprotection 59:19-27. 

5. Drozdowski, J. L. and W. J. Manning. 1984. Strawberry disease survey 
report. Unpublished manuscript. 

6. Grove, G. G., L. V. Madden, M. A. Ellis and A. F. Schmitthenner. 1985. 
Influence of temperature and wetness duration on infection of immature 
strawberry fruit by Phytophthora cactorum . Phytopathology 75:165-169. 

7. Powelson, R. L. 1960. Initiation of strawberry fruit rot caused by 
Botrytis cinerea . Phytopathology 50:491-494. 

8. Schaefers, G. A. 1980. Yield effects of tarnished plant bug feeding on 
June-bearing strawberry varieties in New York state. J. Econ. Entomol. 
73:721-725. 

9. Smith, F. D. and W. E. MacHardy. 1984. The retention and redistribution of 
captan on apple foliage. Phytopathology 74:894-899. 

***** 



20 

POSTHARVEST HANDLING OF BLUEBERRIES 

Wesley R. Autio 

Department of Plant and Soil Sciences 

University of Massachusetts 

Blueberries ( Vaccinium corymbosum ) are very perishable once harvested and 
must be handled carefully to maintain quality and reduce postharvest losses. 
The primary quality factors, as outlined by the U.S. grade standards, are 
maturity, color, size, and freedom from defect and decay (7). In a 3-year 
study of blueberries at retail stores Cappellini et al. (3) determined the 
reasons for postharvest berry losses (Table 1). Of the 15.2% of berries lost, 

Table 1. Sources of blueberry losses in retail outlets. From Cappellini et 
al. (3). 



Percentage 
Defect lost 



Decay 10.7 

Overripe or dehydrated 3.3 

Mechanical or insect injury 0.2 

Immaturity 1 .0 

TOTAL 15.2 



over two-thirds were lost to decay, so efforts to improve postharvest handling 
of blueberries must reduce the incidence of decay to be successful. In this 
discussion I will present general changes which occur during blueberry 
ripening, factors which affect decay, and means for reducing decay and 
increasing postharvest life and fruit quality. 



Ripening 

Blueberries are a climacteric fruit, meaning that they exhibit a rapid 
rise and fall in respiration during the course of ripening. Throughout this 
period many other changes occur, including a reduction in acidity, an increase 
in sugar content, and a dramatic increase in anthocyanin content (the source of 
the blue coloration). Table 2 depicts the timing of the major changes that 
occur during ripening. 

It is interesting to note that blueberries do not attain their full flavor 
when they first become blue, but actually require an additional 1 to 2 days to 
develop full flavor (8). This is reflected in Table 2 by a sharp decline in 
acids (and rise in pH) and rise in sugars after the fruit become blue, both 
changes improving flavor. The sugar/acid ratio reflects both of these changes, 
and is what we perceive when we taste the fruit. 



21 

Table 2. Biochemical changes associated with Wolcott blueberry ripening, 
Adapted from Ballinger and Kushman (1). 









Total 


Soluble 




Sugar/ 


Antho- 








acidity 


solids 


Sugars 


acid 


cyanins 


Stage 


PH 


(% 


as citric) 


(%) 


(%) 


ratio 


(mg/lOOg) 


Immature -green 


2.60 




4.10 


6.83 


1.15 


0.28 


__ — 


Mature-green 


2.68 




3.88 


7.20 


1.79 


0.46 





Green-pink 


2.79 




2.36 


9.88 


5.27 


2.28 


85 


Blue-pink 


2.81 




1.95 


10.49 


6.20 


3.26 


173 


Blue 


2.96 




1.50 


10.79 


6.87 


4.69 


332 


Blue-ripe 


3.70 




0.50 


12.42 


9.87 


19.95 


1033 



Decay 

Decay is the primary source of berry loss after harvest (2). The 3 most 
common decay organisms are anthracnose, gray mold, and alternaria (3). 
Researchers have observed that decay is most prevalent in late-harvested 
berries, where there is a higher percentage of overripe fruit. For instance, 
at retail stores 10.9% of the berries are lost from early season harvests, 
whereas 20.3% are lost from late season harvests (3). This apparent loss of 
resistance to decay is related to the advancement of ripening and has been 
correlated with an increase in the sugar-to-acid ratio (1) (see Table 2). 
Thus, as fruit ripen their sensitivity to decay during the postharvest period 
increases, and the sharpest increase is during the very latest stages of 
ripening. 

The primary entry point for decay organisms is the stem scar. Table 3 
shows results of a study where some fruit had their stems removed and some did 
not. Decay increased much more rapidly in those fruit where the stems were 
removed, leaving stem scars. 

Table 3. Percent decay associated with the stem scars of harvested blueberry 
fruit. From Cappellini and Ceponis (2). 



Days at 70'^F 



Treatment 



With stems 


0.1 


0.6 


0.9 


Without stems 


0.7 


3.8 


6.7 



22 

Decay can be controlled adequately with postharvest fungicide dips but 
resistance to applying pesticide after harvest and problems with application 
preclude their use. Other means must be used to control postharvest decay. 

Postharvest Handling 

The simplest and most effective way of maintaining blueberry quality after 
harvest is with the use of refrigeration . Cold temperatures slow ripening and 
nearly stop decay. Some resistance to the extensive use of refrigeration of 
blueberries exists because many growers are concerned that the sweating of 
fruit after removal from the cold can increase decay, but research has shown 
that decay is not significantly increased by sweating (4). 

The optimum conditions for holding blueberries are 31 to 32*^F and 95% 
relative humidity. Even at 40° there is substantially more loss to decay than 
at 32" (Table 4). Under most circumstances, blueberries may be kept for 2 



Table 4. Percentages lost associated with holding temperature, 
and Kushman (6). 



From Hruschka 



Length of storage 



Holding 
temperature 


2 wks 


2 wks + 
2 days at 70° 


4 wks 


4 wks + 
2 days at 70° 


32° 
40° 


10 
13 


18 
28 


18 
30 


36 
55 



weeks at 32° with very little loss (4). However, if some loss can be tolerated 
they may be kept for up to 6 weeks. Late-harvested berries will not store as 
well as early-harvested fruit, and any decay present at harvest will reduce 
storage potential by providing an inoculum source (7). 

Also, it is critical to cool the berries as quickly as possible. Ceponis 
and Cappellini (5) studied the differences in losses associated with cooling 
rate. Berries were cooled in 2, 48, or 72 hours and kept at 35°F for 2 weeks, 
after which they were removed from storage and kept at 70° for up to 3 days. 
Table 5 shows their results, and it is obvious that rapid cooling reduced 
losses, particularly in the first 2 days after being transferred to 70°. Many 
growers may not have cooling equipment available to reduce the temperature of 
their berries to 35° in 2 hours, but it is important to cool them as quickly as 
possible . Some success has been obtained by supplementing existing cooling 
equipment with liquid nitrogen or CO2 to speed the cooling process (9). 

Modified atmospheres around the fruit may improve longevity. Elevated CO2 
(10 to 15%) seems to be the most advantageous modification because it inhibits 
the growth of decay organisms. Table 6 shows data on fruit losses to decay 



23 

Table 5. The effects of cooling rate on the percent loss of blueberries. From 
Ceponis and Cappellini (5). 



Days at 70*'F after 2 wks at 35° 



Cooling times (hrs) 



2 
48 
72 



0.8 


2.0 


6.8 


17.2 


2.7 


6.9 


14.1 


20.7 


3.7 


10.8 


20.6 


24.8 



after cold storage with high CO2. The CO2 enriched atmosphere significantly 
reduced loss during and after storage. The use of CO2 enrichment of storage 
rooms may not be feasible for blueberry growers, but enrichment of small lots 
of fruit may be accomplished with the use of plastic films. Research studies 
have used plastic envelopes to enclose several 1-pint baskets and have injected 
CO2 directly into the envelopes to enrich the atmosphere. A high CO2 
environment will develop naturally after enclosure in plastic but will take 5 
to 7 days to reach 10-15%. Even with this delay in the development of a high 
CO2 atmosphere the benefits of sealing in plastic may be significant. However, 
plastic must be removed when the berries are removed from cold storage . 

Table 6. The effects of CO2 enrichment on the percent loss of blueberries 
after cold storage. From Ceponis and Cappellini (5). 



Days at 70° after 2 wks at 35° 



Percent CO2 



12 to 15 0.9 2.1 5.7 12.6 

2.4 6.6 13.8 20.6 



CONCLUSIONS 

1. Keep blueberries COLD (31 to 32°F). The most effective means of 
maintaining blueberry quality is through refrigeration. 

2. Cool blueberries QUICKLY. Significant benefits exist from rapid cooling. 

3. Seal in plastic to increase CO2 if longer storage is desired. Research 
has shown that high CO2 can significantly reduce blueberry losses to 
decay. Plastic films may be used to develop and maintain a high CO2 
environment around the fruit. 



24 
References 

1. Ballinger, W. E. and L. J. Kushman. 1970. Relationship of stage of 
ripeness to composition and keeping quality of highbush blueberries. J. 
Amer. Soc. Hort . Sci. 95:239-242. 

2. Cappellini, R. A. and M. J. Ceponis. 1977. Vulnerability of stem-end 
scars of blueberry fruits to postharvest decays. Phytopath. 67:118-119. 

3. Cappellini, R. A., M. J. Ceponis, and G. Koslow. 1982. Nature and extent 
of losses in consumer-grade samples of blueberries in greater New York. 
HortScience 17:35-36. 

4. Cappellini, R. A., M. J. Ceponis, and C. P. Schulze, Jr. 1983. The 
influence of "sweating" on postharvest decay of blueberries. Plant 
Disease 67:381-382. 

5. Ceponis, M. J. and R. A. Cappellini. 1983. Control of postharvest decays 
of blueberries by carbon dioxide-enriched atmospheres. Plant Disease 
67:169-171. 

6. Hruschka, H. W. and L. J, Kushman. 1963. Storage and shelf life of 
packaged blueberries. U.S.D.A. Agric. Market. Res. Rep. 612. 

7. Kader, A. A., R. F. Kasmire, F. G. Mitchell, M. S. Reid, N. F. Sommer, and 
J. F. Thompson. 1985. Postharvest technology of horticultural crops. 
Cooperative Extension, University of California. 

8. Ryall, A. L. and W. T. Pentzer. 1982. Handling, transportation, and 
storage of fruits and vegetables. Vol. 2, AVI, Westport, CT. 

9. Saltveit, M. E., Jr. and W. E. Ballinger. 1983. Effects of anaerobic 
nitrogen and carbon dioxide atmospheres on ethanol production and 
postharvest quality of blueberries. J. Amer. Soc. Hort. Sci. 108:459- 
462. 

•k -k ic if if 



COOPERATIVF EXTENSION SERVICE 
U S DEPARTMENT OF AGRICULTURE 
UNIVERSITY OF MASSACHUSETTS 
AMHERST MASS 01003 



OFFICIAL BUSINESS 

PENALTY FOR PRIVATE USE. S300 



BULK RATE 


POSTAGE & FEES PAID 


USDA 


PERMIT No G2r,8 



Fruit Notes,""; 

Prepared by: Department of Plant and Soil Sciences ' ^' MA S ^ 

Massachusetts Cooperative Extension, University of Massachusetts, United 
States Department of Agriculture and Massachusetts counties cooperating. 



Editors: W. R. Autio and W. J. Bramlage 



Volume 52, No. 4 
FALL ISSUE, 1987 




Table of Contents 

Evaluation of Mcintosh Strains 
in Massachusetts 

Potato Leafhopper in Massachusetts 
Apple Orchards 



Redfree: A High Quality, Early-season, Disease- 
resistant Apple 

Effects of Fertilization on Apple Quality 

Pomological Note: Rabbits in Orchards 

Cranberry IPM in Massachusetts — What it Means 

and How it Works 

Growth Regulators in Orchard Management 

Pomology Group Moves 

Orchard Mice and Voles 



EVALUATION OF NCINTOSH STRAINS IN MASSACHUSETTS 

Wesley P.. Autio, William J. Lord, and William J. Bramlage 

Department of Plant and Soil Sciences 

University of Massachusetts 

Many Mcintosh strains have been discovered throughout the years. Some 
have been good and others not so good. To be accepted now, new strains must 
have a high percent red color, yield well, and emerge from long-term storage 
with high quality. To assess Mcintosh strains, a planting was established in 
1979 at Green Acres Fruit Farm, Wilbraham, MA, including Morspur, Marshall, 
Imperial, Macspur, Eastman, Gatzke, and Rogers Mcintosh on M.7A. This planting 
is maintained by the grower. 

Trees have fruited since 1983, and the yields are reported in Table 1. 
Most strains, with the exception of Eastman, yielded similarly each year and on 
a cumulative basis. Eastman trees yielded the fewest fruit each year from 1983 
to 1986, with a cumulative yield less than half that of the other strains. 
Eastman also was the smallest tree in terms of trunk circumference (Table 1). 
However, this fact did not account for the low yields, since they also were the 
least yield efficient trees from 198:) to 1986 (Table 1). 



Table 1. Yield per tree (bu) in 198j through 1986 and on a cumulative basis, 
cumulative yield efficiency, and 1986 trunk circumference of Mcintosh strains 
planted in 1979. 



Yield per tree (bu) 

Yield Trunk 

efficiency circum. 

Strain 1983 198^ 1985 1986 Cumulative (kg/cm^) (cm) 



Morspur 


0.4 ab* 


1.1 ab 


1.1 abc 


5.2 a 


7.7 a 


2.31 


a 


27.7 a 


Marshall 


0.3 be 


1.4 a 


1.1 be 


4.1 a 


6.8 a 


2.11 


ab 


27.8 a 


Imperial 


0.5 a 


1.1 ab 


1.6 ab 


4.8 a 


8.0 a 


2.11 


ab 


29.7 a 


Macspur 


0.3 be 


1.0 ab 


1.0 be 


4.4 a 


6.7 a 


1.72 


be 


29.5 a 


Eastman 


0.2 c 


0.1 c 


0.5 c 


1.9 b 


2.7 b 


1.52 


c 


20.5 b 


Gatzke 


0.2 be 


0.5 be 


1.2 ab 


4.3 a 


6.3 a 


1.88 


abc 


27.7 a 


Rogers 


0.3 be 


1.1 ab 


1.8 a 


4.9 a 


8.1 a 


2.17 


ab 


29.4 a 


* Within 


columns. 


means not 


followed 


by the 


same letter 


are 


sign 


if icantly 


different. 

















As fruit ripen their starch is converted to sugar which is observed easily 
by staining the starch with an iodine solution. The pattern of staining 
changes during ripening and can be categorized by comparing it to an index 
chart. As the starch disappears the index value increases. For two harvests 
in 1983, three in 1984, two in 1985, and one in 1986 starch index values were 
determined with the starch-iodine test (Table 2). No consistent differences 



were seen among the strains, suggesting that there were no differences with 
respects to the time of ripening. However, the starch-iodine test is not very 
sensitive for assessing small differences. 

Table 2. Starch index values of fruit from different strains of Mcintosh 
harvested in 198J, 1984, 1985, and 1986. 

1983 198M 1985 1986 



Strain 9-9 9-17 9-4 9-11 9-18 9-3 9-10 9-4 



Morspur 


1.9 ab* 


2.5 a 


2.6 a 


3.2 abc 


4.7 


a 


3.2 a 


4.7 a 


3.5 b 


Marshall 


1.9 ab 


2.8 a 


2.2 a 


3.4 ab 


4.1 


a 


3.2 a 


4.1 a 


3.8 a 


Imperial 


1.7 ab 


2.7 a 


2.2 a 


3.2 abc 


4.1 


a 


3.3 a 


4.6 a 


5.2 c 


Macspur 


1.9 a 


2.6 a 


2.2 a 


3.6 a 


4.5 


a 


3.4 a 


4.7 a 


3.6 ab 


Eastman 


1.3 b 


2.8 a 













2.5 b 


4.0 a 


3.1 c 


Gatzke 


1.8 ab 


2.3 a 


2.2 a 


3.1 be 







2.8 ab 


4.4 a 


3.1 c 


Rogers 


1.5 ab 


2.i a 


2.0 a 


2.9 c 


4,1 


a 


3.0 ab 


4.1 a 


3.4 be 



* Within columns, means not followed by the same letter are significantly 
different. 



During the course of apple ripening the internal C2H4 concentration rises 
dramatically, providing an accurate and sensitive means of monitoring ripening. 
For three harvests in 1984 and 1985 the internal C2H4 concentration was 
determined for Marshall and Rogers fruit (Table 3). We were particularly 
interested in determining if Marshall fruit ripened earlier, since they colored 
significantly earlier than the other strains. Rogers was selected as a 
standard strain. In both years, Marshall fruit ripened significantly earlier 
than Rogers fruit, showing higher internal C2H4 concentrations at each harvest. 
In 1986 internal C2H4 concentrations were determined for all strains on 
September 4 (Table 3). Marshall fruit had the highest levels, and over the 
three years of the study comparison of concentrations suggest that Marshall 
fruit ripen about 5 days before standard strains such as Rogers. 

The primary factor in determining success when growing Mcintosh is red 
color. For an orchard to be profitable, a large percent of the fruit produced 
must have enough red color to meet the U.S. Extra Fancy grade, i.e. 50 percent 
red color characteristic of the cultivar. Table 4 shows the percent of the 
fruit meeting the Extra Fancy grade for each harvest in each year. In all 
cases Marshall had the highest percent of fruit in the Extra Fancy grade. 
Also, earlier coloring of Marshall fruit can be observed in those years where 
multiple harvests were made. 

Flesh firmness was measured at harvest each year (Table 5). Significant 
differences were noted among the seven strains. However, these differences may 
be attributed to differences in fruit size (Table 6). Generally, the smallest 
fruit were the firmest. 



Table 3. Internal C2Hi( concentrations of fruit from different Mcintosh strains 
harvested in 1984, 1985, and 1986. 



Strain 



9-4 



1984 



9-11 



9-18 



8-27 



1985 



9-i 



9-10 



1986 



9-4 



Morspur 

Marshall 

Imperial 

Macspur 

Eastman 

Gatzke 

Rogers 



0.12 a* 4.60 a 11.50 a 0.10 a 3.15 a 14.93 a 



0.04 b 



0.65 b 3.80 b 0.05 b 



0.51 b 



2.12 b 



0.35 b 
1.29 a 
0.48 ab 
0.40 b 
0.46 ab 
0.62 ab 
0.28 b 



* Within columns, means not followed by the same letter are significantly 
different. 



Table 4. Percent of fruit meeting the U.S. Extra Fancy grade harvested from 
different Mcintosh strains in 1983, 1984, 1985, and 1986. 







1983 






1984 




1985 


1986 


Strain 


9-1 


9-7 


9-14 


9-4 


9-11 


9-18 


9-S 


9-10 


9-4 


Morspur 


17 b" 


20 b 


57 be 


13 b 


23 b 


72 b 


30 b 


20 b 


75 ab 


Marshall 


64 a 


67 a 


84 a 


51 a 


89 a 


90 a 


77 a 


65 a 


95 a 


Imperial 


15 b 


23 be 


68 ab 


23 b 


13 be 


72 b 


12 c 


21 b 


80 ab 


Macspur 


8 be 


33 b 


56 be 


9 b 


23 b 


63 b 


18 be 


17 b 


81 ab 


Eastman 


1 c 


6 c 


25 d 


— 


— 


— 


5 c 


4 b 


61 b 


Gatzke 


9 be 


17 c 


52 be 


8 b 


8 c 


— 


10 c 


14 b 


80 ab 


Rogers 


8 be 


28 b 


39 cd 


7 b 


8 c 


67 b 


7 c 


14 b 


73 ab 



Within columns, 
different. 



means not followed by the same letter are significantly 



In 1985 one bushel of fruit from each tree was kept in controlled 
atmosphere storage for 7 months followed by air storage for 2 months. In 1986 
one bushel from each tree was kept in air storage for 4 months, and one bushel 
was kept in controlled atmosphere storage for 6 months followed by air storage 
for 1 1/2 months. The incidences of storage disorders were not significantly 
different among strains in either year (Table 7). However, some differences 
existed with respect to fruit firmness after storage in 1986, but these 
differences may be attributed to fruit size. 



Table 5. Flesh firmness (lbs) of fruit harvested from different Mcintosh 
strains in 1983, 1984, 1985, and 1986. 

198i 198'< 1985 1986 



Strain 9-9 9-17 9-4 9-11 9-18 9-3 9-10 9-4 

Morspur 15.5 ab* 14.5 ab 16.6 a 15.3 ab 14.7 a 15.7 a 14.0 ab 14.8 a 

Marshall 15.5 ab 14.9 a 16.3 ab 15.5 ab 15.3 a 15.8 a 14.4 a 14.8 a 

Imperial 15.3 ab 14.4 abc 16.1 ab 15.5 ab 14.8 a 15.5 ab 14.1 ab 14.6 ab 

Macspur 14.7 b 13.8 cd 15.7 b 14.6 c 14.2 b 15.0 be 13.1 c 14.3 c 

Eastman 14.8 b 13.6 d 14.7 c 13.8 b 14.2 c 

Gatzke 15.3 ab 14.0 bed 15.6 b 15.0 be 14.4 c 1j.3 e 14.4 be 

Rogers 16.0 a 14.5 abc 16.5 a 15.7 a 15.3 a 15.7 a 14.3 ab 14.7 ab 

* Within columns, means not followed by the same letter are significantly 
different. 



Table 6. Diameter (in.) of fruit harvested from different Mcintosh strains in 
1984, 1985, and 1986. 



1984 1985 1986 



Strain 9-4 9-11 9-18 9-3 9-10 9-4 



3.13 ab 3.10 b 3.22 b 3.04 b 

3.03 b 3.04 b 3.10 c 2.95 c 

3.16 a 3.13 b 3.22 b 3.15 a 
3.16 a 



Morspur 


2.93 b* 


3.01 b 


Marshall 


2.89 b 


2.98 b 


Imperial 


2.97 b 


3.03 b 


Macspur 


3.02 ab 


3.11 al 


Eastman 








Gatzke 


3.13 a 


3.19 a 


Rogers 


2.89 b 


3.03 b 



3.09 b 


3.25 b 


3.05 b 


3.27 a 


3.29 ab 


3.20 a 


3.30 a 


3.39 a 


3.16 a 


3.04 b 


3.17 be 


3.03 b 



3.14 ab 

* Within columns, means not followed by the same letter are significantly 
different. 

In summary, Eastman produced a small tree which yielded poorly. Other 
strains produced trees of similar size and productivity. Marshall produced 
fruit which colored earlier and to a higher degree and ripened earlier than 
fruit from other strains. Fruit quality after storage was similar for all 
strains in this study. Another Mcintosh strain trial was established in 1985 
with a number of high-coloring strains, including Redmax. Results from this 
study will be reported in future issues of Fruit Notes. 



Table 7. Post-storage quality of fruit harvested from different Mcintosh 
strains in 1985 and 1986. Fruit in 1985 were harvested September 10, kept in 
CA (3% O2, 5% CO2) for 7 months and air for 2 months prior to quality 
assessment. Fruit in 1986 were harvested September 4 and either kept in air 
for 4 months or CA for 6 months and air for 1 1/2 months prior to quality 
assessment. 













Senescent 


Bitter 






Firmness 


Scald 


Decay 


breakdown 


pit 


Browncore 


Strain 


(lbs) 




(X) 


(%) 


(i) 


(5t) 


(%) 










CA— 1985 








Morspur 


9.8* 


0» 


17* 


14* 


— — 


3* 


Marshall 


10.1 







28 


23 


— 





Imperial 


10.3 







13 


15 


— 


1 


Macspur 


8.7 







30 


27 


— 





Eastman 


10.0 







27 


14 


— 





Gatzke 


9.6 







22 


25 


— 


1 


Rogers 


9.6 




1 


14 
Air— 1986 


19 




1 


Morspur 


10.1 


ab*» 


6» 


8« 


11* 


5* 


__ 


Marshall 


10.0 


ab 


6 


9 


7 


1 


— 


Imperial 


9.8 


ab 


10 


8 


15 


4 


— 


Macspur 


9.2 


b 


3 


7 


11 


3 


— 


Eastman 


9.3 


ab 


9 


7 


11 


5 


— 


Gatzke 


9.1 


b 


9 


22 


12 


5 


— 


Rogers 


10.3 


a 


8 


11 

CA— 1986 


6 


2 




Morspur 


10.7 


be 


2* 


3* 


2* 


5* 


^mm 


Marshall 


11.6 


a 


2 


2 


1 


2 





Imperial 


10.8 


be 


4 


2 





6 





Macspur 


10.3 


c 


1 


3 


1 


4 





Eastman 


11.3 


ab 


1 


6 


2 


3 





Gatzke 


11.2 


ab 


3 


3 


1 


3 





Rogers 


11.1 


ab 


1 


2 


1 


2 


^" 



* No significant differences existed among strain for these parameters. 

** Within column and storage treatment, means not followed by the same letter 
are significantly different. 

• • « » » 



6 

POTATO LEAFHOPPER IN HASSACHUSETTS APPLE ORCHARDS 

Kathleen Leahy, Ronald J. Prokopy, and William M. Coli 

Department of Entomology 

University of Massachusetts 

In 1986, many growers, private consultants, and Extension workers noted a 
"new" type of injury on terminal leaves of apple, consisting of general off- 
coloration as well as a strong marginal yellowing or burning of the leaves. 
Since the injury was not particularly severe and no causative agent was found, 
in most cases it went unremarked during the growing season. It was not until 
the fall, when Extension workers and private consultants from the Northeast 
gathered to share information, that the problem was recognized as a widespread 
phenomenon, and the injury was definitively identified as caused by the potato 
leafhopper, (PLH) Empoasca fabae . Over the decades, this insect is known to 
have been an occasional pest of apples, but this has been the most notable 
outbreak in recent years. 

Nymphs and adults of PLH are pale green in color, and tend to move rapidly 
(often in a sideways fashion) when disturbed. In contrast, nymphs and adults 
of the white apple leafhopper (the only other leafhopper likely to be seen in 
Massachusetts apple orchards) are pale yellow to whitish in color and move more 
slowly when disturbed, usually straight ahead. An additional distinguishing 
character visible with a hand lens is a rather distinctive whitish "H" pattern 
on the top of the thorax of a PLH adult. And, of course, the location (new, 
succulent terminal growth) and type of damage (yellowing and "burn" as opposed 
to stippling) are also diagnostic. 

PLH overwinter as adults in the South, and move northward in warm masses 
of air, usually beginning in June. They fall out when the warm air collides 
with cooler northern air. Eggs are laid in the veins and petioles of newly- 
developing foliage of a variety of plants. Nymphs feed on tender terminal 
leaves. There are two and possibly three generations of PLH here in the 
Northeast. Luckily, apple is not the most favored host of this insect. It was 
discovered in 1841, feeding on beans. By the late 1800's it had become a pest 
of potatoes, its preferred host. Other favored hosts include clover, alfalfa, 
and beets. Fortunately, most (but not all) PLH apparently leave apple trees 
after completing the first generation. By that time, the growth of terminal 
foliage in most orchards has hardened off to an extent where PLH prefer other 
plants having more succulent foliage. However, in plantings of young trees or 
on older trees producing vigorous mid- to late season growth, PLH can continue 
to be a problem until August. 

The first evidence observed in 1987 of PLH on apple in Massachusetts was 
on July 8 in a Wilbraham orchard. Over the next few weeks, PLH continued to 
disperse into most locations in Massachusetts. In general, infestations have 
been heavier this year than they were last. To illustrate, in surveys during 
July in 18 orchards participating in the second-stage IPM program, we found 
about 10? of terminals of bearing trees in sprayed (control) blocks manifesting 
signs of PLH injury. 

In most cases observed in 1987, PLH injury first appeared as a general 
off-coloration (partial yellowing) of new terminal growth. It was only after 



some weeks that the diagnostic "hopper burn," or yellowing of leaf margins, 
began to appear. In a few severe cases, particularly where trees were also 
stressed by drought, leaves later became curled and somewhat browned about the 
margins. 

Since PLH has only been a sporadic pest on apple, the effects of this 
injury on affected trees are not well known. Because PLH inject a toxin into 
the plant, in many crops (such as potatoes) the threshold for these insects is 
very low. It is likely, however, that fruit trees, because of their size and 
the enormous amount of vegetative growth of which they are capable, can 
withstand considerably higher numbers of PLH. Until we know better, we have 
adopted a provisional threshold for PLH that is the same as that for white 
apple leafhopper, 25 leafhoppers or signs of feeding per 100 terminals 
observed. 

PLH are extremely mobile, rendering monitoring and management decision- 
making difficult. For one thing, PLH will take flight at a fairly slight 
disturbance, so that moving terminals for examination may cause the leafhoppers 
to fly off. (According to researchers working with PLH, ovipositing females 
are much less easily disturbed than males. This fact may make it possible at 
least to determine whether the insects are still present, but difficult to 
assess actual population levels.) 

It is also difficult to assess the susceptibility of potato leafhopper to 
insecticides. In 1986 in New York, where PLH infestation was more severe than 
it was in Massachusetts, PLH were observed on terminals in blocks which had 
been treated with organophosphate insecticides. This observation led tree 
fruit entomologists there to speculate that resistance had developed, but 
vegetable specialists raised the possibility that reinfestation had occurred in 
those blocks, and that no resistance was present. Vegetable specialists in 
both New York and Massachusetts note that PLH are highly dispersed over a wide 
geographic range and a variety of plant hosts, many of which are never exposed 
to pesticides. These factors would tend to inhibit the development of 
resistance in most cases. 

Pesticide control results in Massachusetts in 1987 have been inconclusive, 
but we can state with confidence that we have not seen any sign of continued 
infestation of trees treated with organophosphate insecticides (OP's). In 
fact, in the one monitored orchard where an OP was used against PLH, 
infestation declined from ^7% of terminals the week before treatment to 0% the 
week after. The reason that it is not possible to state definitely that this 
decline was due to the OP treatment is that similar declines also occurred in 
untreated orchards, over the same period of time, possibly because terminal 
growth was beginning to harden off and PLH were moving onto other hosts. 

Based on the recommendations of vegetable specialists, and the fact that 
no obvious OP resistance has been noted on any crop in Massachusetts in 1987, 
we are proceeding with the assumption that PLH are indeed susceptible to OP's, 
including Imidan and Guthion. 

Since it appears that potato leafhopper migration is determined primarily 
by prevailing weather conditions in the southern U.S., it is impossible to 
predict whether this insect will continue to be a problem on apples in 
Massachusetts. However, since such outbreaks have happened in the past, we 



8 

hope to be armed with more information to handle the next one, whenever it may 
occur. We are involved currently with assessing injury levels in heavily- 
infested blocks in order to determine whether PLH injury affects premature 
drop, fruit size or color, or fruit set the following spring. 



« « « « « 



ERRATUH 

A Report of the 1986 Massachusetts Apple IPM Program 

William M. Coli, Daniel R. Cooley, Kathleen Leahy, and Ronald J. Prokopy 

University of Massachusetts 

In the article on the Apple IPM Program results published in the Spring 
issue of Fruit Notes [52( 2) : 1 1-16] , we neglected to acknowledge the 
contribution of the Regional Fruit Specialists, Jim Williams in particular, to 
the IPM program. In addition to being responsible for sending the twice-weekly 
Pest Alert Messages, the Regional Specialists have shared information gathered 
from their orchard visits with us. Jim also has done regular, weekly IPM 
scouting in at least one orchard for the past 4 seasons, and his assistance has 
been of great value to the IPM Program, allowing us to extend our monitoring to 
parts of the state which University-based scouts are unable to visit regularly. 
We regret having omitted Jim's name, as well as Dom Marini and Karen Hauschild, 
from the list of credits for all who have helped the program. 



• « • • » 



REDFREE: A HIGH QUALITY, EARLY-SEASON, DISEASE-RESISTANT APPLE 

Daniel R. Cooley 
Department of Plant Pathology 

and 

Joseph Sincuk 

Department of Plant and Soil Sciences 

University of Massachusetts 

Early season apples are often thought of as second-rate fruit, stop-gaps 
until the real show begins with Mcintosh. Redfree may not change the attitude 
we have about Mcintosh, but it may offer an excellent opportunity for high- 
quality, early-season fruit. The disease resistant planting at the 
Horticultural Research Center, Belchertown, MA, has two Redfree trees, both of 
which fruited heavily this year. The fruit were ready to pick August 10, making 
it harvestable at about the same time as Jersey Mac and approximately 1 week 
earlier than Paulared. When the fruit were harvested, most had approximately 



65i red color with a green ground color, while approximately 10J had greater 
than 80% red color with a yellow-cream ground color. Later taste testing 
showed that the fruit with the cream ground color were too ripe, though they 
were sweeter (Table 1). The fruit with a greener background were more tart, 
similar to Empire. These greener fruit were judged as good, comparing well 
with any early-season fruit. The texture of the fruit was very good, and the 
fruit were firm (Table 1). 

Table 1. Flesh firmness and percent soluble solids of Redfree divided into 
average and high-coloring lots and Jersey Mac. One group of Redfree fruit was 
kept at room temperature for ^ days prior to assessment. 

Red color Time at Flesh firmness Soluble Solids 
Cultivar (.%) room temp. (lbs) (%) 



Redfree 82% fresh 14.9 11.1 

Redfree 63% fresh 18.1 10.5 

Jersey Mac 61% fresh 15.5 10.2 

Redfree 63% ^ days 17. 'i 10.3 



Redfree comes from the Purdue-Rutgers-Illinois breeding program, and as 
such is resistant to apple scab, cedar apple rust, fire blight, and mildew. It 
may also be resistant to red mite. Among the named parents in Redfree 's 
heritage are Rome Beauty, Jonathan, Red Rome, and Melba. It is an annual 
bearer. Some descriptions suggest that it may require two pickings, though if 
the fruit are harvested prior to peak color, this activity may not be necessary 
and quality may be higher. Redfree presently is available from The Nursery 
Corporation (Hilltop). 

While the information we gathered this year is very preliminary, it looks 
like Redfree could be an excellent early-season apple, regardless of its 
disease-resistant characteristics. It is reported to keep for up to 2 months 
in refrigerated storage, and we found no serious loss of quality in ^ days at 
room temperature. However, it appears that the fruit should be harvested early 
rather than at or near full ripeness, since both taste quality and keeping 
quality are lower in the ripest fruit. When compared to Jersey Mac picked a 
few days earlier (Table 1), Redfree were sweeter but less juicy. Soluble 
solids and firmness were both somewhat higher in the Redfree. If this season 
is typical of Redfree 's quality, then it could compete well with any of the 
popular early-season cultivars. 



» « « « « 



10 

EFFECTS OF FERTILIZATION ON APPLE QUALITY 

William J. Lord 

Department of Plant and Soil Sciences 

University of Massachusetts 



It is necessary to produce apples with high quality, and many orchard 
factors can affect quality. However, one of the most important and easiest to 
alter is nutrition. Below are presented some of the effects of fertilization 
on fruit quality. 



Calcium 

Initially, the concern about low fruit calcium was directed at bitter pit 
and cork spot, but today many other physiological disorders have been at least 
partly related to low calcium levels in the fruit. In warmer fruit growing 
areas cork spot and bitter pit remain the most serious effects of low calcium; 
but in cooler areas various forms of internal breakdown are the most serious 
calcium-deficiency problems. 



Nitrogen 

Excessive amounts of nitrogen in the tree and fruit can severely reduce 
fruit quality. The vigorous growth that nitrogen encourages results in a lower 
calcium level in the fruit. Moreover, the high nitrogen fruit tend to be 
larger, greener, and softer; are more subject to preharvest drop; and have more 
cork spot and bitter pit. These fruit also tend to develop greater am.ounts of 
scald, bitter pit, internal browning, and internal breakdown during and after 
storage. 

Potassium 

Potassium deficiency has only a mild effect on fruit quality, reducing the 
acidity of the fruit and reducing red coloration. Excessive amounts of 
potassium in fruit are a greater danger to fruit quality, since they lead to 
increased scald, bitter pit, and internal breakdown after storage. 

Magnesium 

There is little evidence that either too little or too much magnesium 
directly affects fruit quality. However, excess magnesium interferes with 
calcium just as does excess potassium, so excessive amounts of magnesium may 
produce calcium deficiency effects in fruit. 

Phosphorus 

Phosphorus deficiency can reduce tree growth and yield, and in several 
parts of the world it also has been shown to cause increased amounts of 



11 

breakdown of apples during storage. However, in North America there has been 
very little evidence of phosphorus deficiency in fruit. We recently have found 
that high levels of phosphorus in apples, especially in combination with low 
levels of calcium, greatly increases breakdown of apples during storage. 

Boron 

Boron deficiency can cause internal and external cork development in 
fruit. Excessive levels of boron in fruit can cause earlier maturation, 
increased amounts of water core at harvest, and increased amounts of breakdown 
after storage. Thus, a moderate level of boron is important for good fruit 
quality. 

Boron also influences calcium movement in the tree. If boron is 
deficient, less calcium moves to the fruit and calcium deficiency can result. 
It therefore is important to maintain adequate boron levels as part of a 
program to avoid calcium deficiency. 



« K » « « 

POHOLOGICAL NOTE 

Rabbits in Orchards 

William G. Lord 

Plant Science Department 

University of New Hampshire 



Cottontail rabbits can be found throughout southern New England and often 
cause serious damage to young apple trees. Damage generally includes extensive 
bark removal and severe clipping of lateral shoots. 

Habitat control is an effective population control measure. Overgrown 
ditches, brushy fence rows, and stone walls provide rabbits with excellent food 
and protection from predators. Elimination of these areas may be all that is 
needed for adequate rabbit control. 

Trees can be protected from rabbits by hardware cloth (1/2" mesh) tree 
guards that extend 2' above the average snow depth. Orchard perimeter fencing 
or 1" or 1 1/2" mesh wire that extends S' above the average snow depth is also 
effective. 

Taste repellents are another effective method of reducing rabbit damage to 
orchards. Repellents containing Thiram have been effective when applied 
according to label directions. Other commercial products such as Hinder also 
provide effective control. 



« « « « « 



12 

CRANBERRY IPM IN HASSACHUSETTS — WHAT IT HEANS AND HOW IT WORKS 

Joan A. Lasota 

Cranberry Experiment Station 

University of Massachusetts 

East Wareham, MA 



Tn 1986 a record cranberry crop (1.8 million barrels) was produced in 
Massachusetts, where the total earnings reached approximately $90 million. 
This level is a 7 percent increase from the previous season, making the 1986 
crop the largest in Massachusetts history and makes the state the leading 
cranberry producer in the U.S. for the third consecutive year. Cranberries are 
this state's most valuable agricultural commodity, accounting for 23 percent 
of the total cash receipts in 1985. The average per acre harvest is currently 
149.3 barrels, an increase from 70.1 barrels in 1975. The price per barrel 
also has increased — from $13 in 1975 to $55 in 1985. This figure was between 
$52 and $5^* in 1986. Ocean Spray Cranberries, which markets approximately 80% 
of the fruit sold in Massachusetts, increased its sales from $361 million in 
1982 to $541 million in 1985 and expects to continue this trend. 

Results of a pesticide survey conducted for pesticide-treated cranberry 
acreage in 1983. 1984, and 1985 indicated that greater than 60 percent of all 
pesticides used on cranberries in Massachusetts were insecticides. Evaluation 
of the period between 1981 and 1985 showed that the number of insecticide 
applications for bogs in Massachusetts increased by a factor of 1.6 in 1984; 
however, this figure decreased to 1.0 in 1985, making 1981 and 1985 equivalent 
in terms of the number of insecticide application. Tn all cranberry growing 
regions, parathion was the most widely used insecticide. It was used on at 
least three times as many acres as any of the other insecticides. A gradual 
decrease in the use of parathion in bogs has been noted and may be related to 
an increase in the use of 'orsban, an insecticide which only recently became 
registered for use on cranberries in Massachusetts. 

Environmental contamination, hazards to human and other non-target 
organisms, increased monetary costs of pesticide applications, and the 
increased probability of resistance to pesticides demands that current and 
future research efforts focus on an integrated approach to pest management, 
emphasizing minimal use of chemical pesticides. Depressing the use of 
chemicals is particularly important in highly residential areas, such as 
southeastern Massachusetts, to help prevent environmental contamination. 
Pollution of aquifers is of particular importance. Additionally, the proximity 
of cranberry bogs to homes results in fear of pesticide drift on the part of 
homeowners. Recently, growers have been faced with public hearings on 
proposed bills requiring notice 60 days prior to pesticide application. There 
also have been hearings to ban all aerial applications in certain towns. 
Pressure from external sources is forcing growers to contemplate alternatives 
to the standard, prophylactic, calender application of pesticides, a spray 
schedule which has little or no regard for pest population levels. 

Integrated pest management (IPM) means the judicious use of chemical 
control measures while taking full advantage of cultural, mechanical, and 
biological controls. With IPM, calender-based spray schedules are replaced by 
chemical controls which are based on sampling and monitoring pest populations. 



13 

By first determining when and at what quantities pests are present, we can 
time accurately chemical applications to coincide with damaging pest levels. 
The intent of IPM rarely is the elimination of pesticides. It usually means 
minimizing chemical use. The benefits of IPM are not only realized at the time 
of implementation of the program but are also long-term. Ecological, 
economic, and sociological concerns are paramount when considering development 
or implementation of an IPM program. 

Integrated pest management gives maximum consideration to the fine 
ecological balances among all of the components of an agricultural system. 
Attention is paid to the life cycles of the pests and the extent of their 
interaction with the host plant. Host plant phenology, or the developmental 
stages of plants, are investigated extensively together with the pest and 
natural enemy life cycles. 

Tn an IPM program, the decision whether or not to implement control 
measures is based upon economic threshold levels. These levels are the lowest 
pest population densities that will result in economic damage. Thus, it is 
important to monitor pest populations throughout the growing season so that 
control decisions can be made to prevent economic losses. It is also important 
that the cost of control does not exceed the marketable value of the commodity. 
Because pests and their population levels change during the course of the 
growing season, threshold levels may be different for different plant parts and 
at different times during the season. 

Threshold levels are based on two types of pests: 1)direct pests - those 
which affect the marketable part of the plant, for example, the berries of a 
cranberry plant, and 2)indirect pests - those which attack the non-marketable 
parts, for example, leaves, stem, and roots. Because the fruit are the parts 
of cranberries which are marketed, the threshold levels for direct pests are 
extremely low, especially if the berries are sold for fresh-market purposes. 
Keep in mind, that the importance of attack on the different plant parts varies 
from crop to crop. In the case of ornamentals where the entire plant is used 
for aesthetic purposes, direct and indirect pests may be of equal importance 
from an economic standpoint and the need to control. 

The Cranberry IPM program (1983 to 1985) successfully sparked grower 
interest in the concepts if IPM and demonstrated significant monetary savings. 
As growers become increasingly aware of the benefits of IPM, they tend to 
utilize information distributed via this program, regardless of whether of not 
they are formal participants in the program. 

1986 and 1987 Scouting Program 

Fifteen growers were involved in the cranberry IPM program in 1986. This 
figure more than doubled in 1987, with 33 participants. The total number of 
acres in the 1986 program was 208, increasing to 450 in 1987. The largest 
acreage contracted from an individual grower was 50 and the smallest was 0.58. 
All growers were visited in early May by the cranberry IPM coordinator to 
discuss specifics and procedures for the program. Also at this time, 
recommendations were made for spring weed control. 



14 

Bogs were scouted weekly by the IPM coordinator and summer scouts, from 
the beginninR of May until September. This scouting involved monitoring insect 
pests with the use of sweep nets, pheromone traps, and vine and berry samples. 
Diseases and weed pests were also identified and monitored. Growers were 
notified via telephone or in person regarding the pest status of their bogs and 
recommendations for control. Copies of weekly reports were given to growers. 
In September, growers received graphs and reports for cranberry fruitworm and 
pests which were monitored with pheromone traps. Also in September, bogs were 
sampled for weed problems to aid in making spring and fall herbicide 
recommendations. Berry and vine samples were collected to determine end-of- 
season damage (particularly upright dieback, berry rot, cranberry fruitworm, 
and cranberry tipworm damage). 

Insect monitoring is related to host plant phenology. The following 
pests are most prevalent in spring and early summer and are damaging to the 
vine uprights. They are leaf feeders; however, they are most destructive when 
they damage developing buds. Sampling with sweep nets (25 sweeps/acre) was 
conducted weekly, from mid-May through the end of bloom. 

gypsy moth blossom worm black headed fireworm 

Sparganothis fruitworm cranberry sawfly false armyworm 
yellow headed fireworm cranberry weevil spanworms 

The adult flight activity of the following pests were monitored with the 
aid of pheromone traps. Traps were set out in late May and were changed and 
counted weekly, until early to mid August. 

cranberry girdler 
Sparganothis fruitworm 
blackheaded fireworm 

Southern red mite is a potential pest throughout the growing season, 
although its populations are highest during the summer. It was monitored by 
collecting and inspecting 10 to 15 uprights/acre for eggs, immatures, adults, 
and damage. Large populations may also be seen during sweeping. Cranberry 
tipworm is a potential pest during most of the growing season, damaging the 
tips of uprights. Uprights were collected and inspected in the laboratory for 
the presence of eggs, larvae, pupae, and damage. Following the first two 
cranberry fruitworm sprays, which are timed depending on when the plant is 50% 
out-of-bloom, 50 berries/acre were collected every five to seven days and 
inspected for the presence of viable cranberry fruitworm eggs until there was 
no longer the danger that viable eggs were being deposited. The percentage of 
parasitized eggs was also determined at this time. 

Just prior to harvest, 50 berries/acre and 10 vines/acre were collected 
and brought into the laboratory for inspection. Insect, disease, and 
mechanical damage were identified. 

This article is intended to be an introduction to the Cranberry IPM 
program, some of the cranberry pests, and the procedures used during pest 
monitoring. More detailed results will be presented in future issues. 



« « « « « 



15 

GROWTH REGUUTORS IN ORCHARD HAMAGEHENT 

Duane W. Greene 

Department of Plant and Soil Sciences 

University of Massachusetts 

Growth regulators are an important component of apple production. They 
are used more intensively on apples than on any other horticultural crop, and 
they can regulate important physiological processes, resulting in higher and 
more consistent yields of high-quality fruit. Growth regulators include 
hormones found naturally in the plant and similar synthetic compounds. 

Chemical Thinning 

The oldest, yet probably the most important, use of plant growth 
regulators remains in the area of chemical thinning. Apple trees frequently 
produce too many flowers, and if all flowers set fruit which develop to 
maturity, the fruit will be too small and flower bud formation for the crop the 
following year will be either reduced or eliminated. Chemical thinners can be 
applied from shortly after bloom until about ^ weeks afterwards. Weather 
conditions determine the exact length of time during which fruit can be thinned 
chemically. 

Carbaryl is the mildest and safest thinning agent, but it should not be 
used at bloom time because it is especially toxic to honey bees. Some growers 
also are reluctant to use this compound because of its possible adverse effect 
on predator mites. 

Naphthaleneacetic acid (NAA) is a more potent thinner and is used on the 
more difficult to thin cultivars and on those cultivars that have a 
particularly heavy bloom. Naphthaleneacetamide (NAAm or NAD) is milder than 
NAA and is used when NAA could cause injury or leaf dwarfing. NAD is not 
recommended for use on Delicious because of the possibility of producing many 
small, seedless fruit called "pygmies." Promalin^M, applied with a surfactant, 
has some thinning ability when used to elongate Delicious. Spray combinations 
of carbaryl and NAA or NAD are becoming increasingly popular — especially where 
growers want to get increased thinning, yet reduce the possibility of 
overthinning or foliar damage seen with the higher rates of "AA or mad. 

Preharvest Drop 

Daminozide (Alar-85^^) is the most important compound used to control 
preharvest drop. It is most effective when applied near harvest, but label 
restrictions specify that it cannot be applied within 50 days of harvest. 
Since daminozide is less effective when application is made earlier in the 
season, it should be applied as close to harvest as the label will allow. 
Daminozide is under review by the EPA and its future registration status is in 
question. 

NAA also retards preharvest drop. It becomes effective within one day of 
application, and it can control drop for 7 to 10 days. If needed a second 
application may be made. NAA has the negative effects of advancing ripening 
and causing fruit softening. 



16 



Advancing Fruit Ripening 



Ethephon (Ethrel^^) can advance the marketing season of most cultivars by 
increasing red color and advancing ripening. Also, it will accelerate fruit 
drop if applied alone. Therefore, this compound should either be applied with 
NAA or on trees that received daminozide earlier in the season. If 
temperatures are very high following application and the weather remains 
cloudy, sufficient red color may not develop on treated fruit until ripening is 
significantly advanced. Because of this potential problem, ethephon should be 
used on young trees, since light penetration is usually very good and fruit on 
these trees frequently is too large to have a long storage life. Ripening may 
advance rapidly on ethephon-treated trees. They should be watched very 
carefully so that harvesting can be done before excessive fruit drop occurs. 

Growth Control and Flower Bud Formation 

Frequently young trees grow too rapidly thus failing to flower and set 
fruit. Also, older trees may become too vigorous due to over-fertilization, 
excessive pruning, or the loss of a crop due to frost. Daminozide, ethephon, 
or a combination of daminozide and ethephon may be used to retard growth and 
increase flower bud formation. Treatments should be applied when terminal 
shoot growth is 4 to 6 inches long. Concentrations of ethephon high enough to 
reduce terminal growth will also cause excessive fruit thinning. Therefore, 
ethephon must not be used on trees where cropping is desired the year of 
application. Young trees should not be sprayed with daminozide and ethephon 
until they are large enough to bear a crop. 

Water Sprout and Root Sucker Control 

Water sprouts are vigorous, upright shoots arising from any portion of the 
above-ground part of a tree. They are most prevalent on vigorous trees 
carrying a light crop. Heavy pruning encourages water sprout growth. It is 
desirable to restrict growth of these shoots for two reasons: the shade they 
produce retards red color development, and removing them adds to the pruning 
costs. Tre-Hold Sprout Inhibitor A112^^ (ethyl ester of NAA) is used to 
inhibit growth of these shoots. It usually is mixed with interior latex paint 
and applied to pruning cuts. The paint allows the applicator to see the 
treated areas, and the increased viscosity of the mixture reduces movement to 
nontarget areas of the limb. It is important that the inhibitor be applied 
during the dormant season, because volatilization of the NAA from applications 
made after the buds start to grow can cause some leaf epinasty and fruit 
thinning. 

Root sucker control also may be achieved with Tre-Hold. Root suckers 
should be pruned during the dormant season and the regrowth treated with a Tre- 
Hold spray. Application should be delayed in the spring until four weeks after 
bloom to reduce the possibility of fruit thinning. Thorough coverage is 
essential for success. If there is tall grass or weeds on the orchard floor, 
it may be useful first to spray under the trees with a contact herbicide such 
as paraquat. Ten to fourteen days later, follow the herbicide application with 
the Tre-Hold treatment. Extreme care must be taken to prevent drift since the 
recommended rate of '''re-Hold is ^00 to 1000 fold higher than the recommended 
rate of NAA for chemical thinning or drop control. 



17 



Lateral Branching 



Many young trees, especially spur types, fail to branch adequately. This 
lack of branching can limit the ultimate productivity of the tree, because the 
allotted space will not be filled. To stimulate lateral branching, Promalin 
may be applied in the spring when terminal growth is 1 to ^4 inches long. Only 
vigorous, healthy trees should be treated, since Promalin will not overcome a 
lack of branching due to poor growth. The high rate of Promalin should be used 
only on diff icult-to-branch trees. High rates of Promalin on easily branched 
trees can stimulate too many lateral shoots, all of which will be too short to 
develop into good scaffold limbs. Promalin should be used only on nonbearing 
trees, because the rates required to stimulate lateral branching will thin the 
crop the year of application and inhibit flower bud formation for the following 
year. 

Elongate Delicious 

The Delicious grown in New England normally are not as elongated as those 
grown in the Pacific Northwest. To elongate Delicious fruit, Promalin may be 
applied when the king flower is open. Promalin can thin, especially if a 
surfactant is included and the highest rate of Promalin is applied (2 
pts/acre). Promalin should not be used on young trees until they are old 
enough and ready to be chemically thinned. 



« « » » « 



POMOLOGY GROUP HOVES 

In the middle of August three members of the pomology group of the 
Department of Plant & Soil Sciences at the University of Massachusetts moved 
from French Hall to Bowditch Hall. The new addresses and telephone numbers for 
Wesley Autio- William Bramlage, and Duane Greene are listed below. James 
Anderson, William Lord, and Franklin Southwick will remain in French Hall. 



Wesley R. Autio 
205 Bowditch Hall 
University of Massachusetts 
Amherst, MA 01003 
Tel. 413-545-2250 



William J. Bramlage 
308 Bowditch Hall 
University of Massachusetts 
Amherst, MA 01003 
Tel. 413-545-2254 



Duane W. Greene 
304 Bowditch Hall 
University of Massachusetts 
Amherst, MA 01003 
Tel. 413-545-2259 



« « « « « 



18 

OBCHABD HICE AND VOLES 

Alan Eaton 

Department of Entomology 

University of New Hampshire 



Mice and voles are closely related rodents that can be distinguished from 
each other on the basis of tail and ear size, among other minor differences. 
In New England, mice are not a problem in orchards, but two species of voles 
frequently cause serious damage. These pests are the meadow vole and the pine 
vole. Meadow voles range throughout New England, but pine voles are known to 
be present only from southern New England to southern Vermont, New Hampshire, 
and the southern tip of Maine. 

Meadow voles inhabit the orchard floor, developing a network of surface 
trails through the groundcover and feeding primarily on grasses and fleshy 
herbs. This species usually does most of its damage during the winter when 
herbage is less abundant, but damage is possible at any time of the year. They 
chew away areas of bark and cambium that can be reached from the ground or from 
higher positions in or on snow cover. In some soils they will burrow and 
sometimes are responsible for trunk girdling several inches below the ground 
surface. 

Pine voles travel either in surface trails or in burrows 3 or more feet 
deep depending somewhat on soil conditions. In solid grass sods, they may be 
almost totally subterranean; but where the groundcover contains a high 
percentage of broadleaf herbs, pine vole may travel on the surface. During the 
cold months, their activity is pretty much limited to the underground burrows. 
When herbage is abundant, pine voles store caches in the tunnel system for 
later use. They feed upon bark and cambium primarily below the soil line, and 
chew off small roots up to about the diameter of a pencil. All commercial 
apple cultivars and their seedlings, as well as the available rootstocks, are 
very susceptible to vole feeding. 

Identification of Pest Species 

When vole damage is apparent, it is important to determine which species 
is responsible. Some of the management practices used for meadow voles are not 
effective against pine voles. Identification of the species may require 
trapping. Use snap traps baited with rolled oats, or peanut butter, or a 50:50 
mixture of these two. Fresh apple pieces are also a good bait. Place traps 
across active runs, including those that lead into underground burrows if they 
are present. Cover the trap with an apple box or a similar cover. This will 
exclude birds and cats and help you locate the trap trees in the orchard. Set 
enough traps to be sure of catching 5 to 10 voles from various locations in the 
orchard. Check the traps after only one or two days. Tail length is useful 
for identification. The pine vole tail is very short — about the same length as 
the hind foot (not the leg!), measuring 3/^ inch or less. The meadow vole's 
tail is about twice the length of its hind feet, reaching 1 1/2 to 1 3/^ inches 
on adults. Both species have chunky bodies and small beady eyes, and their 
ears are small and almost concealed in fur. The fur color is dark brown or 
gray-brown. If you catch a long-tailed specimen, it is likely to be a white- 



19 

footed mouse. This mouse's tail is well over ? inches long, and all underpants 
of this mouse are covered with white fur. It is reported to eat the bark of 
young trees occasionally, but it is generally considered a non-pest species in 
orchards. Your traps may also catch a shrew, which is a beneficial small 
mammal, or a mole, which is neither harmful nor beneficial. A shrew can be 
identified by its long, pointed snout and its needle-pointed front teeth. 
Moles can be identified by their front feet, which are very large, with 
prominent digging claws. 

Orchard Floor Management 

Prevention of vole population build-ups offers the most practical method 
of reducing tree injury. 

1. Mow orchard floor sod frequently during the growing season. 

2. Maintain a vegetation-free area within at least '< feet of the tree trunks. 
The use of herbicides may be necessary to accomplish this. 

3. Eliminate brush and thick vegetative cover around orchard perimeters. 
^. Completely remove all fruit drops from the orchard. 

Tree Guards 

Maintenance of proper tree guards is the most effective measure for 
preventing tree girdling by meadow voles, unless snow depth exceeds the height 
of the guard. Voles tunnel through snow to any depth. Also, trunk guards do 
not prevent underground damage by pine voles. 

Galvanized hardware cloth is one of the best materials for tree guards. 
One-quarter-inch mesh in 2'4-inch width is preferred. The cloth is cut large 
enough to completely encircle the tree and allow enough room for 10 or more 
years of growth. The cloth is formed into a cylinder and fastened together so 
that no gaps are left through which the mice can gain entry. Two or 3 short 
pieces of wire may be necessary to secure the seam. The guards are embedded at 
least 2 inches into the soil to prevent the rodents from burrowing underneath. 
An annual check of the guards is recommended, preferably before the ground 
freezes. The disadvantages of hardware cloth are that it is difficult to work 
with and installation is time-consuming. 

Several rigid, perforated polyethylene or plastic mesh products are being 
promoted for use as tree guards. Each is used in a way similar to that of 
galvanized hardware cloth to form a cylinder which is buried in the ground and 
is of large enough diameter to give free circulation to air and to allow for 
tree growth. These products are easier to handle than wire guards, but some 
may be broken down by ultraviolet light and may have a limited life. 

Wrap-around plastic guards are readily available, cheap, and easy to 
install but are not recommended unless they are removed each spring and 
installed again in the fall . Various borers seem to prefer trees with wrap- 
around plastic or paper guards. Also, the bark beneath plastic guards remains 



20 

tender and hardens slowly, the plastic may become brittle when weathered, and 
these guards are difficult to keep in place on trees with uneven trunks or 
swollen graft unions. 

Paper wrap-around guards are not recommended. They must be tied off with 
string which can girdle the tree unless it is removed in the spring. Very high 
populations of bark borers have been found in trees protected with this 
material. The treated paper also weathers quickly, and the protected bark 
remains tender and hardens slowly. 

Rodenticides 

Poison baits are of two types: zinc phosphide and anti-coagulant. Just 
one or two fresh grains or pellets of zinc phosphide-treated bait can quickly 
kill the vole that eats it, whereas it may take several days of feeding on 
anti-coagulant baits to kill voles. Owing to the caching habit of pine voles, 
poison baits that are taken by the species may not be consumed until much 
later, or not at all. Zinc phosphide breaks down slowly in moist air, and it 
loses its toxicity rather quickly if the bait becomes wet. To preserve the 
toxicity of unused zinc phosphide baits, place the opened package within a 
plastic bag and seal the bag tightly. 

Rodenticide Techniques 

Broadcast . Broadcast applications of baits can be effective against 
meadow voles. However, they are usually not effective against pine voles. 
Bait should be directed into live ground cover where meadow voles forage, 
rather than into herbicide-treated strips. Most product labels limit 
treatments to the postharvest, dormant period. The presence of dropped apples 
can make baiting ineffective; however, as apples are a preferred food for 
voles. All sound drops should be removed before bait is broadcast. If the 
weather is wet and dark during the first few days after broadcasting, the 
baiting effort will have been wasted. Wet weather and dark days discourage 
vole activity, and wet bait loses potency and palatability. Try to bait just 
before a mild, fair-weather period of several days. 

Baiting in Artificial Trails . Mechanical trail-builder baiting machines 
construct trails beneath the soil surface and supply baits at regular intervals 
for meadow or pine voles that enter those trails. According to the U.S. Fish 
and Wildlife Service, which can furnish plans to construct the device, this 
technique can be effective against both pine and meadow voles. Sod cover and 
reasonably moist soil are required at the time the machine is pulled through 
the orchard. Generally, one trail is made along each side of the tree rows, 
beyond the wheel tracks, beneath the drip line of the trees, and in sod. 
Trails should be cut 2 to ^ inches deep, with bait placed at ^- to 5-foot 
intervals. 

Hand-baiting . Hand-baiting implies selective placement of baits where 
vole activity is most likely or where active trails or burrows are located. 
Bait is placed in quantities of one teaspoon, at the rate of 2 to 3 lbs per 
acre. To greatly speed bait placement, bait stations such as asphalt roofing 
shingles or split tires should be distributed beneath the trees in sodded areas 



21 

well in advance of baiting time. Over a period of weeks or months voles 
develop trails under these bait stations — trails that can be baited quickly 
after harvest. 

Orchard Floor Sprays . Liquid Rozol^^ (chlorphacinone) is an anticoagulant 
formulated for spray application. In order for it to be effective, it must 
thoroughly wet and penetrate the ground cover. Before the spray is applied, 
the ground cover should be dry and mown short enough for maximum penetration. 
Voles are killed after repeated exposure to residues on the ground and cover 
crop. Liquid Rozol will not be effective when there is no surface-feeding 
activity. 

Estimating Vole Activity 

Vole activity can be estimated by placing apples in runways or tunnel 
entrances. Place whole, firm apples, with a thin slice removed, at regular 
intervals throughout the orchard where activity is suspected. After 24 hours, 
look for small teeth marks in the apples. If such a check indicates voles are 
present 2 to 3 weeks following a baiting, a second treatment may be needed. 

Re-treatment with Baits 

Where some voles have been sickened by a rodenticide treatment but have 
survived, the acceptance of the same bait a second time within a few weeks will 
be poor. This problem seems to be more common with zinc phosphide baits than 
with anticoagulants. If a second treatment is needed, use a different bait 
(e.g., if zinc phosphide was used in the earlier treatment, use an 
anticoagulant for the follow-up). Obviously, the best way to deal with this 
problem is to prevent it from occurring: do everything possible to kill all of 
the voles with the first treatment. 



Orchard Borders 

In the brushy areas immediately adjacent to a vole-infested orchard, one 
can generally find a relatively high population of the same species that is 
present in the orchard. If these border areas are not baited, they will be a 
source of reinfestation of the treated orchard. 



Caution 

Rodenticide baits may be attractive to domestic pets, wild birds, and 
other nontarget wildlife. Exposed bait, and especially exposed piled bait, 
increases the chances of nontarget injury. As with all pesticides, use good 
judgment and take reasonable precautions to avoid problems. 



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Fruit Notes 

Prepared by the Department of Plant & Soil Sciences 

University of Massachusetts Cooperative Extension, 

United States Department of Agriculture, and Massachusetts Counties cooperating. 



ISSN 0427-6906 



f Editors: Wesley R. Autio and William J. Bramlage 






1988 




Volume 53, Number 1 
WDSTTER ISSUE, 1988 



Table of Contents 



Apple Scald, A Complex Problem 

Can M.9 Rootstocks be Used Profitably in 
Massachusetts Apple Orchards? 

Nine Years of Apple IPM Implementation at the 
Horticultural Research Center 

Dormant Pruning to Improve Packout of Mcintosh 

Are Asian Pears for New England? 

Variable Conditions in CA Storage Can Cause Fruit 

Disorders After Storage 

Publications Available from the University of Massachusetts 



APPLE SCALD, A COMPLEX PROBLEM 

William J. Bramlage 

Department of Plant and Soil Sciences, University of Massachusetts 



Symptoms . "Scald" is a term loosely applied 
to a group of skin disorders of apples and pears. 
It involves brown or gray discoloration of 
irregularly shaped areas on the surface of the 
fruit during or following storage. On apples, 
Wilkinson and Fidler (5) described the following 
forms of scald: 

a. "Rugose scald": skin initially develops a faint 
bronze color, but later these areas turn Ught 
brown to very dark brown. The surface 
layers of cells are dead and so they dry out 
and collapse, leaving a brown, sunken 
appearance. Usually, many lenticels remain 
green, however, standing out prominently 
from the sunken areas. 

b. "Browning scald": the lenticels do not remain 
green, the injury progressively invades deeper 
into the flesh, and areas often slough off 
because they remain moist. 

c. "Lenlicel spot scald": the injury is 
predominantly around the lenticels, so that it 
appears as a spotting rather than a blotchy 
disorder. 

d. "Stem-end browning": the injury is primarily 
on the shoulder, radiating from the stem-end 
cavity, which remains relatively free of the 
disorder. 

It appears that all of these forms are 
expressions of the same problem, with specific 
cultivars being more prone to one form or 
another. However, there are many other forms of 
fruit injury that also may cause skin damage that 
is similar to one of these forms of scald. For 
example, we have noted frequently a large amount 
of lenticel spotting after storage which is clearly 
the result of field treatments, presumably 
pesticides, even though there was no evidence of 
damage at harvest. This spotting could easily be 
mistaken for "lenticel scald". Especially on 
Mcintosh, we often see "black scald", a clearly 
defined black area almost always occurring on the 
red side of the fruit. This injury is actually a 
form of sun scald, even though it usually is not 



present at harvest, and could be confused with 
"browning scald". With very ripe fruit, friction 
damage can cause injury that could be confused 
with either "browning scald" or "stem-end 
browning". On pears, "scald" is often a symptom 
of over-storage. Thus, there is often much 
confusion about what is being called "scald". 

Nature of scald . True scald is an 
expression of damage and death within the 
surface layers of cells in localized regions. It 
never occurs on the tree, only after relatively 
long periods of storage. Its development is 
believed to be divided into four stages: 1. The 
first 6 to 8 weeks after harvest, when changes 
occur in the fruit that create the potential for 
scald development, although scald does not yet 
occur; 2. The next 5 to 8 weeks when changes 
continue so that scald can no longer be 
prevented although it still has not appeared; 3. 
The remainder of storage, when scald may slowly 
appear; 4. Post-storage, when scald rapidly 
develops. Thus, the first 6 to 8 weeks after 
harvest are crucial for applying scald control 
measures, and post-storage conditions can 
determine how extensively the scald symptoms 
will appear. For example, we have noted much 
more scald under humid post-harvest conditions 
than under dry ones. 

An outstanding series of research papers in 
the late 1960's and early 1970's, mostly from 
Australia, established much of what we know 
about the chemistry of scald development. It 
was shown that early in storage fruit accumulate 
a chemical called alpha-farnesene; being a 
volatile compound, much of it can evaporate 
from the fruit. As storage time lengthens the 
alpha-farnesene is oxidized to a group of 
compounds called conjugated trienes, which do 
not evaporate and continue to accumulate as 
long as the fruit are kept in storage. These 
conjugated trienes apparently are toxic to the 
cells, damaging them and eventually causing their 
death, which is accompanied by their brown or 
black discoloration, drying out, and collapse. 
Since most of the alpha-farnesene is found in 
the fruit peel, most of the conjugated trienes 



are made in the peel, and therefore these arc the 
cells that are killed. 

Factors affecting scald . Different cultivars 
vary greatly in scald susceptibility. For example, 
Cortland is extremely susceptible and nearly was 
abandoned until effective scald-control methods 
were developed. On the other hand, Golden 
Delicious has very low susceptibility. The huge 
increase in production of Granny Smith worldwide 
has intensified concern about scald, since this 
cultivar is extremely scald susceptible. 

Susceptibility of a given cultivar is not 
constant, however. It is widely recognized that 
immature fruit tend to be more susceptible than 
over mature ones. Although this relationship is 
not invariably true, it is strong enough that 
growers should be much more concerned about 
scald on early-picked than on latc-pickcd fruit. 

Color is another important factor. Scald is 
more likely to occur on a green area than on a 
well-colored area of the fruit. This relationship 
is probably indirect; good exposure to sun is 
probably what reduces scald susceptibility, rather 
than red pigments. Thus, the production of red 
strains of susceptible cultivars largely obscures 
the fact that shaded areas and shaded fruit are 
more susceptible than exposed areas and exposed 
fruit. Excessive tree vigor and inadequate 

pruning (hence, fruit shading) probably increase 
scald susceptibility, while summer pruning 
probably decreases it. 

Scald susceptibility varies considerably from 
year to year for a given cultivar. To a large 
extent this variability is the result of the 
influence of weather on scald susceptibility. 
Studies in England (2) showed that weather 
conditions from late July to the beginning of 
September were very important: hot, dry weather 
increased scald susceptibility; cool, damp weather 
decreased it. Indications were that water stress 
may have been more important than temperature 
in this relationship. Studies in New Jersey (3) 
showed that hot weather shortly before harvest 
increased scald susceptibility; when Stayman 
Winesap apples had experienced 190 or more hours 
of temperatures below 50"F they did not develop 
scald, but as this total dropped scald 
susceptibility increased. Thus, a cool moist 
August and a cool harvest season should greatly 
reduce scald susceptibility; whereas, a hot dry 



August and a hot September should increase it. 
How these two periods interact is not clear. 
For example, 1987 had a hot dry August but a 
cool September. Is one of these situations more 
important than the other? 

Control measures . Numerous approaches to 
controlling scald have been developed, since 
losses to the disorder can be devastating. Early 
approaches recognized that scald was caused by 
a volatile compound and were aimed at 
maximizing evaporation of the compound from 
the fruit during storage. These techniques 
included use of air purifiers in the storage, 
storage ventilation, and paper wraps that were 
impregnated with mineral oil. These techniques 
reduced the amounts of scald that developed, but 
did not control it. 

CA storage greatly reduces scald. Both low 
O2 and high CO2 can be effective. However, 
since CO2 is most effective at concentrations 
above 5% and most cultivars are susceptible to 
CO2 injury above 5%, for most cultivars the 
greatest benefit from CA is from the low O2. 
The low O2 impedes oxidation of alpha farncsene 
to conjugated trienes, the toxic materials. This 
effect is much greater at 1 to 2% O2 than at 3% 
O2, and many researchers have shown that scald 
can be nearly completely controlled at 1 to 1.5% 
O2. However, in the Northeast we have 
generally been unable to store fruit at less than 
3% O2, so we are unable to take full advantage 
of the scald control from CA. At our 
recommended CA conditions, scald is still a 
potential problem. 

An important factor in scald control 
through CA is rapidity with which CA conditions 
are established. Delayed sealing or slow 

generation of an atmosphere can greatly increase 
the risk of scald development after storage. 
Rapid CA is an excellent scald control measure, 
especially where O2 cannot be reduced below 3%. 

Ethylene-scrubbing during CA storage can 
also control scald. In England, scald virtually 
was eliminated from fruit taken from a 
commercial ethylene-scrubbed storage (1). 
However, the feasibility of ethylene scrubbing in 
commercial storage for most cultivars is doubtful, 
so this method seems to have limited application. 

The most reliable scald-control measure is 



probably the use of the antioxidant chemicals 
diphenylamine (DPA) and ethoxyquin. In the mid- 
1950's Smock (4) found that these materials 
provided excellent control of scald, and following 
their approval by the Food and Drug 
Administration they became standard commercial 
treatments as postharvest dips for fruit destined 
for long-term storage. These materials interfere 
with the oxidation of alpha farnesene to 
conjugated trienes, as does low O2 in a CA 
atmosphere. 

Use of antioxidants is not without its 
problems. The materials must be used with care, 
since excessive dosage can cause severe fruit 
injury. Even use at recommended dosage often 
leads to injury due to entrapment of solution in 
cavities, between fruit, or in wooden containers. 
As this trapped solution evaporates, the 
antioxidant concentrates to injurious levels. 
There is also concern about the risks to 
consumers from residual antioxidants; since these 
materials are volatile, little or no residue should 
persist at the end of storage if the material is 
used properly. However, these materials have not 
been approved in some countries, so treated fruit 
cannot be exported to such countries. 

Current directions . During the past 3 years 
we have been conducting extensive studies on 
scald. Our goal is to reduce dependence on the 
antioxidant chemicals for control. Current 

recommendations are generally based on a "worse- 
case scenario," since growers simply cannot risk 
scald development. However, as is described 
above scald susceptibility is extremely variable 
and maximum treatment is often (usually?) not 
necessary. If we can better quantify the factors 
affecting scald, we should be able to quantify the 
potential for scald and adjust the recommended 
treatment to the actual need. One approach to 
this is through careful collection of climatological 
data in relation to scald development. A 
cooperative study involving a number of fruit 
researchers and directed by Dr. David Blanpied at 
Cornell University is in progress. We are 



attempting a different approach: a search for a 
chemical index of scald susceptibiUty in the fruit 
that might signal the need (or lack thereof) for 
chemical treatments at the time of harvest. 

Scald was probably the single most 
important postharvest problem for apples until 
antioxidant chemicals were approved. For 20 
years after approval little further attention was 
given to this problem. Now interest is renewed, 
largely due to the need to reduce the use of 
chemicals wherever possible. Growers can expect 
to hear much more about scald control measures 
in coming years. 



Literature Cited 

1. Dover, C. J. 1985. Commercial scale 
catalytic oxidation of ethylene as applied to 
fruit stores. In: J. A. Roberts and G. A. 
Tucker (eds.). Ethylene and Plant 
Development. Butterworths, London. pp. 
373-383. 

2. Fidler, J. C. 1956. Scald and weather. 
Food Sci. Abstracts 28:545-554. 

3. Merritt, R. H., W. C. StUes, A. V. Havens, 
and L. A. Mitterling. 1%1. Effects of 
preharvest Jiir temperatures on storage scald 
of Stayman apples. Proc. Amer. Soc. Hort. 
Sci. 78:24-34. 

4. Smock, R. M. 1957. A comparison of 
treatments for control of the apple scald 
disease. Proc. Amer. Soc. Hort. Sci. 69:91- 
100. 

5. Wilkinson, B. G. and J. C. Fidler. 1973. 
Physiological disorders. In: Fidler, J. C, B. 
G. Wilkinson, K. L. Edney, and R. O. 
Sharpies (eds.). Tlie Biology of Apple and 
Pear Storage. Commonwealth Agricultural 
Bureaux, East Mailing, Kent, England, pp. 
67-Dl. 



^^ ^f^ ^t^ ^m^ ^m^ 



CAN M.9 ROOTSTOCKS BE USED PROFITABLY IN 
MASSACHUSETTS APPLE ORCHARDS? 

Wesley R. Autio 

Department of Plant and Soil Sciences, University of Massachusetts 



The title of New York Agricultural 
Experiment Station Bulletin No. 406 (1915) is 
"Dwarf Apples Not Commercially Promising." The 
opinions expressed in that publication certainly do 
not reflect those held by the current researchers 
at the New York Agricultural Experiment Station, 
Geneva; however, there is still much resistance 
among growers to the idea of planting fully 
dwarfed apple trees. In this article data will be 
presented that show that fully dwarfed trees on 
M.9 can be substantially more profitable than the 
much larger trees on M.7, particularly during the 
early fruiting years. 

Figure 1 

Size of Rogers Mcintosh trees 

planted in 1979. 



Feet 




M.7 A 



M.26 M.9 Post M.9 Trellis 



M.9 was one of the earliest dwarfing 
rootstocks available. It was selected as a chance 
seedling in France in 1879 (2) and produces a tree 
only 25 to 50 % of the size of a standard, 
seedling-rooted tree. A number of dwarfing 
rootstocks which produce a tree similar in size to 
that produced by M.9 now are being evaluated and 
some are available, but M.9 still is used more 



extensively worldwide than any other very 
dwarfing rootstock (2). In the U. S. the strain 
of M.9 which is most commonly available is M.9 
EMLA. It was originally propagated from a 
virus-free strain produced by the cooperation of 
East Mailing and Long Ashton Research Stations 
in England, hence the EMLA designation. A tree 
on M.9 EMLA is somewhat more vigorous than 
one on standard M.9. In this study the size, 
productivity, and profitability of trees on M.9, 
M.26, and M.7 were compared. 



Table 1. Trunk circumference in 1987, calculated 
tree density, and approximate spacing of Rogers 
Mcintosh trees planted in 1979. 





Trunk 


Calculated 


Approx. 




circum. 


density 


spacing 


Rootstock 


(cm) 


(trees/acre)* 


(ft) 


M.7A 


43.2 a** 


101 


17x25 


M.26 


30.3 b 


145 


14x22 


M.9 Post 


19.7 c 


277 


9x17 


M.9 Trellis 


19.7 c 


277 


10x16 



^Calculated from 1987 tree spreads (Figure 1). 
**Means within columns are significantly 
different if not followed by the same letter. 



In 1979 a replicated planting of Rogers 
Mcintosh and Macspur trees on M.7A, M.26, and 
M.9 was established by Dr. Franklin W. 
Southwick at the Horticultural Research Center, 
Belchertown, MA. Half of the trees on M.9 were 
trained to individual posts and half were trained 
to simple, 3-wire trellises. At the end of the 
1987 growing season (ninth leaf) trees were 
nearing their mature size. Figure 1 depicts the 
height and spread of the Rogers Mcintosh trees, 
and Table 1 reports trunk circumferences. As 
would be expected, trees on M.7A were the 



Table 2. Yield per acre from Rogers Mcintosh trees and the percent of fruit making the U. S. Extra 
Fancy grade in 1987 from Rogers Mcintosh and Macspur trees planted m 1979. 









Yield per 


acre (hv) 


mvear: 




Total 


U.S. Extra 
Fancy- 1987 


Rootstock 


4 


5 


6 


1 


8 


9 


(%) 


M.7A 
M.26 
M.9 Post 
M.9 Trellis 


67 b* 
84 b 
147 a 
180 a 


147 b 
183 b 
217 a 
307 a 


163 b 
168 b 
294 b 
463 a 


385 c 
426 be 
512 ab 
548 a 


152 b 
165 b 
202 b 
335 a 


388 b 
441 b 
667 a 
669 a 


1302 c 
1467 c 
2039 b 
2502 a 


30 b 
55 a 
59 a 
50 a 



•Means within a column are significantly different if not followed by the same letter. 



largest, reaching nearly 15 ft in height, and trees 
on M!9 were the smallest, not reaching 9 ft. The 
1987 tree spreads were used to calculate tree 
densities and spacings (Table 1) so that potential 
yields per acre could be estimated. Please note 
that these densities represent optimal spacings for 
this planting site, and those used by growers 
should be adjusted as to cultivar, site, and soil 
conditions. 

Table 2 shows yields from years 4 through 9. 
Each year the trees on M.9 produced more fruit 
than those on M.7A or M.26. Additionally, in 
later years and on a cumulative basis trees 
trained to trellises yielded more than those 
trained to individual posts. This observation is 
likely related to a higher fruiting surface per 
acre because of the support given to limbs by the 
trellis. Also in Table 2 are reported the percent 
of fruit making the U. S. Extra Fancy grade in 
1987. These percentages are particularly low 
because harvest occurred prior to optimum 
coloring (September 8). Trees on M.9, both 
posted and trellised, and M.26 had similar 
percentages but all had significantly more Extra 
Fancy fruit than those on M.7A. These smaller 
trees were more open and allowed more light 
penetration and coloring than did the more 
vigorous trees on M.7A. 

Higher yields and better potential packout 
suggest that there are significant advantages to 
planting trees that have been budded to M.9. 
However, this information is not adequate to 
recommend M.9 over the other rootstocks, since 
the costs of producing apples on fully dwarfed 



trees exceeds those of growing larger trees. 
Therefore, it is necessary to look more closely 
at the costs of production for trees on these 
rootstocks and compare that information with 
the potential monetary returns. 



Table 3. Estimated per-acre establishment costs 
of a Mcintosh orchard on M.7, M.26, and M.9 
rootstocks. 





M.7 


M.26 


M.9 


Activity 


Post Trel. 


Site prep.* 

Layout 

Trees 

Planting* 

Posting* 

Trellising* 


700 

20 

500 

125 






700 
30 
725 
175 
300 



700 700 

60 60 

1400 1400 

350 350 

600 

1200 


TOTAL 


1345 


1930 


3110 3710 



*Includes cost of supplies, labor, and equipment. 



Cost data presented in this article are 
estimates based on information from several 
sources, including observations at the 
Horticultural Research Center and published data 
from Cummins and Norton (1), Gerling (3, 4), 
Hanlon et al. (5), Kimball and Autio (6), and 
Norton (7). Plantings of trees on M.9 cost 
significantly more to establish than plantings on 



M.7. Table 3 shows estimated establishment costs. 
The more dwarfing rootstocks required a higher 
tree cost, since more trees were planted per acre. 
They required more labor in layout and planting. 
Also, the cost of posting or establishing a treUis 
was quite high and neither is required for trees 
on M.7. 



Table 4. Itemized per-acre costs of growing 
Mcintosh trees during their second season. 



differences in the costs of maintaining 
nonbearing and bearing trees on these 
rootstocks. Table 6 gives the individual and 
cumulative costs for 9 years for each rootstock. 
The major differences among rootstocks related 
to training requirements, with the trellised trees 
requiring significantly more labor to maintain. 
Also, equipment usage was higher with the 
dwarfed trees because of the greater number of 
rows per acre to travel. The amount of spray 
material required was considerably lower for 
trees on M.9 because of the lower tree volume 













per acre. 


Additionally, the pruning time was 




M.7 


M.26 


M.9 




less for the small trees. 
Table 6. Estimated 


per-acre cost of 




Activity 


Post 


Trel. 














growing 


Labor 










Mcintosh trees during years 1 through 9. 




Pruning 


40 


40 


40 


40 










Training 





25 


50 


150 










Spraying 


35 


45 


60 


60 








M.9 


Other 


50 


50 


50 


50 


Year 


M.7 


M.26 Post Trel. 


Equipment 


150 
140 


200 
140 


250 
140 


250 
140 










Chemicals 










Other 


20 


20 


20 


20 


Yearl 


400 


450 500 


600 


TOTAL 


435 


520 


610 


710 


Year 2 
Year 3 
Year 4 


435 
520 
600 


520 610 
600 700 
630 750 


710 
800 












900 












Year 5 


650 


670 800 


920 


Table 5. 


Itemized 


per-acre 


costs of growing 


Year 6 


720 


710 880 


940 


Mcintosh trees during their ninth i 


season. 




Year 7 


800 


760 880 


950 












Years 
Year 9 


840 
845 


800 890 
805 900 


950 












960 




M.7 


M.26 


M.9 




TOTAL 


5810 


5945 6910 


7730 


Activity 


Post 


Trel. 






The 


costs of trees on M.9 trained 




Labor 










to posts 


Pruning 


195 


130 


65 


65 


and M.9 trained 


on trellis, including 


Training 








40 


100 


estabUshment, growing, 


and harvesting (Table 7), 


Spraying 


45 


70 


90 


90 


were 36% 


> and 57%, respectively, greater 


than for 


Other 


35 


35 


35 


35 


trees on 


M.7. However, the returns (Table 7), 


Equipment 


250 


300 


450 


450 


accounting for yield differences and some 


Pesticides 


250 


200 


150 


150 


variation 


in packout 


during the later 


seasons 


Fertilizers 


50 


50 


50 


50 


when the 


trees were 1 


larger, were 60% ; 


and %% 


Other 


20 


20 


20 


20 


greater than for M.7 


The net profit 


for the 


TOTAL 


845 


805 


900 


960 


first 9 years (Table ' 


7) was $405 per 


acre for 












trees on ] 


M.7 and $4780 for trees on M.9 trained 



to a treUis. 



Growing costs differed as the trees on the 
different rootstocks matured. Tables 4 and 5 
itemize the growing costs for the second and 
ninth growing seasons, respectively, to illustrate 



These data suggest that during the early 
fruiting years Mcintosh trees on M.9 are 
considerably more profitable than those on M.7. 
As these trees reach full maturity the 



Table 7. Total per-acre costs and returns from 
Mcintosh trees during their first 9 growing 
seasons. 



they give a basis for some comparison of these 
rootstocks. 



M.9 



Activity 



M.7 



M.26 



Post Trel. 



COSTS: 
Establishment 
Growing 
Harvesting* 


1345 
5810 
2900 


1930 
5945 
3100 


3110 
6910 
3700 


3710 
7730 
4300 


Total 


10055 


10975 


13720 


15740 


RHIURNS:** 


10460 


12030 


16720 


20520 


NET: 


405 


1055 


3000 


4780 



*Based on a fixed per-acre cost related to 
equipment, picker housing, picker travel, etc. 
plus a per-bushel cost related to harvesting. 
** Based on yields reported in Table 2. 



differences in yield and maintenance costs may 
decline; however, the differences in packout may 
increase. Rough estimates comparing the costs 
and returns for the first 20 years of the planting 
suggest that trees on M.9 trained to a trellis can 
net $10,000 per acre more than trees on M.7, 
accounting for differences in training, spraying, 
yield, and packout. It is important to note that 
the cost estimates used in this study could vary 
greatly from those for an individual farm, but 



Literature Cited 

1. Cummins, J. N. and R. L. Norton. 1974. 
Apple rootstock problems and potentials. N. 
Y. Food and Life Sci. Bui. No. 41. 

2. Ferree, D. C. and R. F. Carlson. 1987. 
Apple rootstocks. In: R. C. Rom and R. F. 
Carlson (eds) Rootstocks for Fruit Crops. 
John Wiley & Sons. New York. pp. 107-143. 

3. Gerling, W. D. 1984. A survey of the cost 
of growing and harvesting apples in eastern 
New York in 1983. Fruit Notes 49(3):12-18. 



Gerling, W. D. 1986. 
costs. Proc. Annu. 

Growers' Assoc. 92:28-35. 



Grower production 
Mtg. Mass. Fruit 



5. Hanlon, W. L., C. E. Willis, and R. L. 
Christensen. 1976. A framework for long 
range apple varietal decisions. Mass. Agric. 
Exp. Sta. Bui. No. 621. 

6. Kimball, M. A. and W. R. Autio. 1987. 
Rejuvenating Mcintosh apple orchards: A 
response to Alar reduction. Univ. Mass. 
Coop. Ext. Circ. C-187. 

7. Norton, R. 1970. High density apple 
planting using clonal rootstocks. N. Y. State 
Hort. Soc. Newsletter 26(3): 1-16. 



^ 



NINE YEARS OF APPLE IPM IMPLEMENTATION AT 
THE HORTICULTURAL RESEARCH CENTER 

William M. Coll, Ronald J. Prokopy, and Kathleen Leahy 
Department of Entomology, University of Massachusetts 

Daniel R. Cooley 

Department of Plant Pathology, University of Massachusetts 

Anthony Rossi 

Department of Plant and Soil Sciences, University of Massachusetts 



Commercial fruit grower adoption of IPM is 
well established in a majority of Massachusetts 
orchards {Fruit Notes 51(2):11-16; 51(3):19-25), and 
such orchards represent a change from pre-IPM 
pest management — a single-minded focus on 
chemical pest controls -- to a more hoUstic IPM 
approach integrating techniques, and disciplines of 
pest management. In the 1987 March Message, we 
described a range of characteristics which we 
believe represent a typical "first-stage" IPM 
orchard. In addition, we have published results 
(Can. Ent. 117:581-585,1985) from Prokop/s 
Conway orchard of 50 disease-resistant apple 
trees that show reduced pesticide use even below 
first-stage IPM levels. 

Since most commercial orchards will not 
contain primarily resistant cultivars for the 
foreseeable future, we believe it is important to 
demonstrate "how low one can go" with pesticide 
use in first-stage IPM blocks which contain the 
usual commercial apple mix, without sacrificing 
fruit quality or quantity. Consequently, we think 
growers would be interested in data we have 
collected in a test orchard that used first-stage 
IPM practices for a number of years. 

This article presents the results of 9 years 
of IPM implementation at the Horticultural 
Research Center (HRC), Belchertown, MA. 
Although the HRC is operated in most respects 
like a typical commercial orchard, it allows us to 
test new approaches to pest management and be 
somewhat less risk-aversive than growers whose 
livelihood depends on successful pest management 
year after year. 

Since 1979, the authors have cooperated to 
implement a minimum-spray program in Block C at 
the HRC, a 2-acre interior block, west of Sabin 



Street and just north of the cold storage 
building. Composed of mostly Delicious strains 
on M.7 rootstocks, with a few Mcintosh mixed 
in, trees are well pruned and fertilized. 

Because of the demands of other research 
being conducted in Block C, fungicide programs 
in the early years were moderately conservative, 
but insect and mite sprays were applied only if 
justified by observations or trap captures in 
excess of economic thresholds. Over the past 3 
seasons, the effort to reduce fungicide in the 
block has been intensified, and has consistently 
included pre-application consultations. Where 
pesticide labels allowed a range of rates (e.g., 4 
to 6 oz/100 gal), we used the low end of the 
range, or lower. Anthony Rossi, the orchard 
foreman, received weekly scouting reports and 
sometimes recommendations. Final spray 

decisions were always his, although he followed 
IPM guidelines very closely. Wherever practical, 
sprays were avoided deliberately, and we 
attempted to avoid the use of predator-harsh 
pesticides (e.g. pyrethroids, carbamates, etc.) as 
a matter of course. When sprays were applied, 
few were at full, labeled rates. Sprays were 
applied with well-calibrated airblast sprayers and 
whenever possible at the same time that the rest 
of the orchard was being covered. Each year, 
we performed harvest surveys and examined 
closely 800 to 1000 fruit on the trees. 

Pesticide use . On average, 2.9 dosage 
equivalents (DE) of insecticide, 1.0 DE oil, 1.3 
DE miticide, 6.0 DE fungicide, and 0.1 DE 
aphicide were applied (Table 1). Insecticide, 
miticide, and fungicide use were all below 
statewide IPM averages {Fruit Notes 52(3):9-12). 
For reasons that are unclear, the HRC has never 
had a problem with apple leafminers, although 



Table 1. Number of spray applications (A) and dosage equivalents (DE) of 
pesticide used in Block C, University of Massachusetts Horticultural Research 
Center, 1979-87. 



Year 


Insecticide 


OU 


Miticide 


Fungicide 


Aphicide 


Total DE 


1979 -A 


3.0 


1.0 


2.0 


9.0 







-DE 


2.3 


1.0 


1.2 


4.5 





9.0 


1980 -A 


5.0 


1.0 


2.0 


9.0 







-DE 


3.0 


1.3 


0.8 


4.8 





9.9 


1981 -A 


3.0 


1.0 


3.0 


8.0 







-DE 


1.6 


1.0 


1.2 


5.6 





9.4 


1982 -A 


4.0 


1.0 


2.0 


8.0 







-DE 


2.8 


1.0 


2.0 


5.6 





11.6 


1983 -A 


2.0 


1.0 


2.0 


11.0 







-DE 


0.8 


1.0 


0.8 


7.7 





10.3 


1984 -A 


3.0 


1.0 


3.0 


11.0 


1* 




-DE 


1.6 


1.0 


1.8 


9.1 


1 


14.5 


1985 -A 


2.0 


1.0 


2.0 


7.0 







-DE 


2.0 


1.0 


1.5 


4.7 





9.2 


1986 -A 


2.0 


1.0 


2.0 


8.0 







-DE 


1.6 


1.0 


0.8 


7.2 





10.6 


1987 -A 


5.0 


1.0 


2.0 


6.0 







-DE 


4.1 


1.0 


1.8 


5.0 





11.9 


9- Year Average 












-A 


3.2 


1.0 


2.4 


8.5 


0.1 




-DE 


2.9 


1.0 


1.3 


6.0 


0.1 


10.7 



*Endosulfan used against green aphids but timed to coincide with first 
summer generation LM adult flight. 



they are present in the orchard (most noticeably 
in the third generation) and a nearby orchard has 
experienced severe leafminer outbreaks and injury. 
Fortunately, this pest has never exceeded action 
thresholds, and no carbamate or pyrethroid 
insecticide has been used in Block C. 

In addition to helping keep insecticide DE 
below state IPM averages, the absence of 
predator-harsh pesticide also has made mite 
control relatively easy in this block, even though 
Red Delicious predominate. The occasional late 
outbreak of ERM, and resultbg egglaying, do not 
appear to be something that annual oil 
applications (Table 1), endemic mite predators, 
and split applications of low miticide rates caimot 
handle. 



Only in one year was any pre-bloom 
insecticide appUed against TPB. Typically, the 
first insecticide was applied at petal fall against 
sawfly and curculio. An average of 1.6 spray 
appUcations (range 1-2) were directed against 
curcuUo. It seems clear that in some blocks at 
least the 3, 4, or even 5 insecticide applications 
some growers use against PC are not required. 

A likely contributing factor to the relative 
ease of mite control in Block C is the relatively 
low number of spray appUcations (avg. 1.6, range 
1-3) used against AMF. In over half of the 
years (57%), first capture of AMF on red sphere 
traps was late enough, and trap captures low 
enough, to enable excellent AMF control with 
only 1 well-timed spray. Only once were 3 
sprays needed, based on monitoring. 



As mentioned above, the fungicide program 
in Block C was moderately conservative and, 
although partly based on hygrothermograph and 
weather monitoring and spore maturity 
determination, likely could be improved upon. 
Fungicide use in Block C largely was driven by a 
perception that the cost:benefit ratio for 
fungicide use was low. To eliminate the 
perceived risk, fungicides were often appUed with 
insecticides and oil sprays. From a high of 11 
appUcations and over 9 DE in 1984, fungicide use 
was reduced in 1987 to the fewest number of 
spray appUcations (6) and the third fewest number 
of DE (5.0) since we began record-keeping in 
1979. This situation was at least partly due to 
the incorporation of a new sterol-inhibiting (SI) 
fungicide into the program. 

Aphicide use in Block C was essentially nil, 
with predators providing control in most years. 
If needed, Anthony Rossi has been able to 
coordinate application of endosulfan against aphids 
and first summer generation adult leafminers. 



Harvest survey results (Table 2). Levels of 
pest injury in Block C were well within 
acceptable ranges for commercial orchards in 
spite of the much lower than average i>esticide 
program. 

As noted in Table 2, disease injury in all 
years was negligible, reflecting a consistently 
successful fungicide program even when less than 
full rates were used. 

Tarnished plant bug was the most frequent 
injury found in samples. A high infestation in 
1983 drove average injury up to 2.4%. However, 
most of the 1983 injury was of the severity and 
type that would not have affected fruit grade. 
In 1983, plum ciu-culio injury reached 1.6%. 

In two years, we experienced late season 
mite buildup. Red mite eggs in the fruit calyx 
were observed, although this "injury" is not 
considered serious by most growers and again 
should have no effect on grade. 



Table 2. On-tree harvest surveys: percent insect, mite, and disease injury, 
Horticultural Research Center, 1979-87. 













Other 


ERM 








Year 


TPB* 


PC 


EAS 


AMF 


insects 


eggs- 


BER 


SCAB 


FS 


1979 


0.8 

















0.2 


0.1 


3.0 


1980 


1.8 


0.3 


0.4 











.*** 


- 


- 


1981 


0.2 














3.7 


0.2 


0.2 





1982 


1.0 


0.3 


1.0 




















1983 


11.5 


1.6 























1984 


0.2 














3.7 


0.2 


0.2 





1985 


1.5 

















0.5 








1986 


- 


- 


- 


- 


- 


- 


- 


- 


- 


1987 


0.3 


0.1 


0.1 














0.1 


0.1 


9 Year 




















Average 


2.1 


0.3 


0.2 








0.9 


0.1 


0.1 


0.4 


(Average Injury 4 


.1%) 

















•TPB, tarnished plant bug; PC, plum curcuUo; EAS, European apple sawfly; 
AMF, apple maggot fly; ERM, European red mite; BER, blossom end rot; 
SCAB, apple scab; FS, fly speck. 
**Eggs in calyx of fruit at harvest. 
***Data not available. 



10 



Table 3. Cost per acre 
Research Center, 1980-87*. 



of spray materials, Block C, Horticultural 















Total 


Year 


Insecticide 


Oil 


Miticide 


Fungicide 


Aphicide 


yearly cost 


1980 


$34.55 


$25.94 


$18.50 


$48.91 





$127.90 


1981 


$14.48 


$26.16 


$24.98 


$48.73 





$114.35 


1982 


$38.29 


$21.60 


$43.80 


$67.96 





$171.65 


1983 


$9.24 


$21.60 


$18.24 


$72.67 





$121.75 


1984 


$18.50 


$21.60 


$41.04 


$82.01 


$41.04 


$204.19 


1985 


$18.48 


$21.00 


$40.77 


$46.47 





$126.72 


1986 


$18.50 


$21.60 


$18.24 


$67.% 





$126.30 


1987 


$43.61 


$21.60 


$27.51 


$50.87 





$143.59 


8 Year 














Average 


$24.46 


$22.64 


$29.14 


$60.70 


$5.13 


$142.06 



*Based on 300 gal/acre dilute base and non-discounted chemical costs. 



It is interesting to note that although apple 
maggot flies were caught in the block, no AMF 
injury was ever detected. In the case of mobile 
pests like the AMF, which normally do not 
establish resident populations in sprayed blocks, 
orchard edges typically experience more pest 
pressure than interiors. We have looked at 
hundreds of fruit in Block C over the years, and 
we have never seen a single fruit damaged by 
apple maggot egglaying. While it is true that 
Block C is an interior block, this points out the 
possibility that growers may be applying more 
insecticide than is needed in similar blocks 
elsewhere. The protection afforded interior 
blocks such as Block C by sprays applied to 
surrounding sprayed blocks may allow some 
growers to achieve signiHcant decreases in 
pesticides required for acceptable pest control. 

Pesticide costs and potential for further 
reduction (Table 3). By better using spore 
maturity and weather monitoring and by including 
SI fungicides against apple scab, we believe that 
fungicide costs can be reduced further. This past 
year, Rubigan^"* allowed longer spray intervals 
between appUcations during frequent wetting. It 
also gave us the confidence to wait until after an 
infection period had occurred before making an 
application. Additionally, information was 

available from both a Reuter-Stokes scab 



predictor and a modified hygrothermograph. 
Having reliable weather information and a 
fungicide with 96 hours post-infection activity 
reduced the perceived risk. 

Without Isirge-scale use of red sphere AMF 
traps, it is unlikely that further significant 
reductions in insecticide use can be achieved, so 
that Uttle additional cost saving compared to 
pre-IPM levels is expected. However, simply 
reducing the total pesticide load in an orchard 
should enhance the survival of mite predators 
and reduce the difficulty of mite pest 
management. Because of the importance of 
spider mite pests, oil is an essential component 
of apple IFM, and will remain a more or less 
fixed cost. Of course, fluctuations in the price 
of oil could significantly increase the cost of 
annual treatment, as in 1980-81. The use of 
mite predator releases in the future may provide 
a way to apply oil only every 2 or 3 years, and 
hence reduce the cost of this material. 

The cost of aphicide would not be expected 
to increase in low-spray blocks, due to enhanced 
survival of aphid predators. Proper tree pruning 
and fertilization will help deter aphid buildup 
beyond economic thresholds. However, 

occasional outbreaks (rosy aphid) could require 
aphicide use. 



11 



Conclusions . From our experience at the 
HRC, we conclude that it is possible, using first- 
stage IPM strategies and technologies, for some 
commercial growers to further reduce amounts of 
pesticide used, and consequently, reduce costs (at 
least in certain interior blocks) without 
sacrificing fruit quality. We urge growers to 
consider a scouting/low-spray approach in a trial 
block so that they can achieve the lowest possible 
spray usage from first-stage IPM. As growers 



move beyond pesticide management toward the 
"Second-Stage" of IPM, pest management 
potentially will include such techniques as 
resistant cultivars, insect growth regulators, 
predator/parasite release or enhancement, 
trapping out pests, mating disruption, oviposition 
deterrents, etc. We are hopeful that second- 
stage IPM research (now under way) will result 
in even greater savings in pesticide cost and 
improvement in farm profitability. 



0^ 4|k ^* ^p ^p 

DORMANT PRUNING TO IMPROVE PACKOUT 
OF MCINTOSH 

Duane W. Greene and Wesley R. Autio 

Department of Plant and Soil Sciences, University of Massachusetts 



A U. S. Extra Fancy Mcintosh apple must 
have at least 50% typical red color, and an apple 
will develop red color only if it is exposed to the 
sun. The higher the light intensity reaching an 
apple, the earlier its red color will develop and 
the more intense its red color will be. The type, 
severity, and location of the pruning cuts 
determine the extent to which fruit on a tree will 
be exposed to adequate light for good red color 
development. Therefore, it is important for all 
growers to conduct dormant pruning that will 
assure good light penetration into the tree canopy 
and high packout. 

Types of pruning cuts and their use . Three 
basic types of cuts are used during the pruning of 
apple trees. These are described below. 

1. Tliinning-out. These are cuts that involve 
removal of an entire shoot or branch at its 
junction with another shoot, a branch, or 
the trunk. This type is the most useful 
pruning cut on mature trees. It can be 
used to redirect branch growth and open up 
the tree for greater light penetration. 

2. Stubbing. This type of cut involves the 
removal of a portion of a branch back into 
2-year-old or older wood. Stubbing is 



usually done to reduce the length of a 
limb or to stiffen a limb so that it does 
not bend down and shade branches below. 
Lateral branching may be increased by this 
type of a cut. Excessive regrowth from 
stubbing can be reduced by cutting to a 
weak sideshoot. 

3. Heading. A heading cut removes a portion 
of 1-year-old wood. On bearing trees 
heading cuts are not recommended, because 
they encourage the development of lateral 
shoots clustered near the cut, which have 
narrow, weak crotch angles. If heading 
cuts are made on a tree over a number of 
years, a mantle of bushy growth will 
develop that will inhibit light penetration. 
Since some of the most productive buds 
are removed each year and others are 
forced to grow into lateral shoots, 
cropping potential on these trees is 
reduced considerably. 

Pruning the bearing tree . The goals of 
dormant pruning of mature apple trees are to 
remove unproductive wood, to encourage the 
continued development of productive wood, and 
to allow maximum light penetration into the tree 
canopy. The types of pruning that are most 



12 



frequently performed to achieve the above goak 
are listed below. 

1. Eliminate branches that are crossing. 
These branches shade fruit and result in 
low quality and poor coloring. 

2. Remove large branches in the tops of trees. 
A conical tree allows the most efficient 
interception of light. A program of limb 
rotation in the upper 1/3 of a tree should 
be conducted to assure that no large limbs 
will develop that might shade fruit or 
prevent the development of scaffold limbs 
below. It is critical that these Umbs be 
eliminated if summer pruning is to be 
effective. They cannot be removed during 
the summer and if present even severe 
summer pruning will not be sufficient to 
overcome the shading. 

3. Eliminate large upright branches. 
Extremely strong branches that compete 
with the central leader will cause problems 
until they are removed. They prevent the 
development of good scaffold branches and 
they frequently cause too much shading. 

4. Remove branches growing toward the center 
of the tree. Branches growing toward the 
center of the tree will increase shading in 
an area prone to low light. 

5. Remove branches with narrow crotch angles. 
Branches with narrow crotch angles are 
weak and frequently break under a fruit 
load or during ice or snow storms. It is 
important to remove branches with poor 
crop potential to allow the growth of better 
limbs with greater potential. 

6. Remove weak wood. Fruit that develop on 
weak branches are characteristically small 



and have poor quality. When fruit on 
these branches begin to grow the branches 
bend down and shade other fruiting 
branches below. 

7. Lower tree height. When trees get too 
tall they become difficult to harvest and 
spray, and the upper portions can shade 
productive branches below. Trees on M.7 
can be lowered to 10 to 14 feet without 
appreciable loss of yield if they have been 
trained to a central leader. 

Don't try to do it all at once . If a tree 
has not been pruned or only has been pruned 
lightly for several years, extensive pruning may 
be necessary. However, growers should not make 
all of the cuts in one year if extensive wood 
removal is necessary. Tree renovation should be 
distributed over at least 2 years. If too much 
wood is removed in one year poor fruit set and 
excessive vegetative regrowth may occur. It is 
important to make sure that there is adequate 
fruit set so that the crop can help control 
regrowth. 

The recommended pruning approach . We 
feel that the pruning approach most useful in 
Massachusetts will involve a combination of 
dormant and summer pruning. It is essential to 
establish the tree shape and make major cuts 
during the dormant season. Large cuts made 
during July and August likely will result in 
extensive fruit bruising caused by falling 
branches. Pruning during the summer should 
emphasize the reduction of shading by removal 
of young, nonfruitful wood. Summer pruning is 
not an expense that is added directly to your 
dormant pruning costs. At the Horticultural 
Research Center dormant pruning of trees that 
were previously summer pruned required 40% less 
time than trees that were not summer pruned. 
Prepare your trees now for summer pruning. 



*•!• »Sg ^f %fe 
^P •P *•* ^r 



13 



ARE ASIAN PEARS FOR NEW ENGLAND? 

James T. Williams 

University of Massachusetts Cooperative Extension, Concord, MA 



Asian pears that we see on the fruit 
counters of local supermarkets are the cultivated 
forms of Pyms serotina (pyrifolia) and Pyrus 
ussuriensis. They are unique in flavor and are 
sometimes called salad pears, apple pears, or 
oriental pears. They are firm, crisp, crunchy, and 
juicy when ripe. Unlike many of our domestic 
pears {Pyrus communis), they obtain their best 
quality when ripened on the tree. 

The Asian pear found its way to the United 
States m mid-1800's during the Gold Rush when 
early Oriental miners brought seeds with them 
from China where these pears were first grown in 
693 A.D. 

Cultivars . The most commonly grown 

cultivars in California are: Shinseiki (early), 
Kikusui (mid-season). Twentieth Century, Chojuro, 
and Ishiiwase (late). Most Asian pear cultivars 
are partly self-fruitful, but better crops can be 
expected when two or more cultivars are planted 
together. 

Spacing, training, and culture . Asian Pears 
can be planted anywhere standard pears can be 
grown. They must have 400 to 900 hours of 
chilling temperatures below 45°F. They are 
planted in the spring as with standard pears. We 
have little experience with spacing requirements; 
however, in California spacings vary from 7.5 x 15 
feet to 15 X 20 feet, depending on the rootstock 
used. These trees can be maintained as free- 
standing, central leader or modified-central leader 
trees. Trellising in Japan using the Pergola 
system gives a continuous, single-layer canopy 
kept at approximately 5 feet off the ground. 
High quality, large fruit are harvested without the 
use of ladders. The Tatura or modified Tatura 
systems, which are "V"-shaped, are established 
with trees spaced 5 x 16 feet and with the two 
main scaffolds sloped 60° from horizontal. 
Fertilizing and other cultural practices are similar 
to those for standard pears. 

Rootstocks . Pyrus betulaefolia is the most 
commonly used rootstock for Asian pears because 
of its vigor, tolerance of wet and poorly drained 



soils, and effect on fruit size. Most Asian pears 
are severely dwarfed on P. communis rootstocks, 
but a few such as TsuU and Ishiiwase are 
compatible and have done well in California. 

Fruit thinning . Thiiming of the fruit is of 
prime importance because premium prices are 
paid for large fruit. During the winter of 1986- 
87 New England supermarket prices for Asian 
Pears ranged from $2 to $3 per pound! Heavy 
crops are frequently set, often with 6 to 8 fruit 
per cluster. Thinning to one fruit per cluster 
and to 5 inches apart will insure good-sized 
fruit. Most growers hand-thin fruit 3 to 6 
weeks after petal fall. When trees are not 
thinned, alternate bearing can develop. 

Pests. Pear psylla is the most serious pest 
of Asian pears, but Asian pears appear to be less 
attractive and suffer less damage than standard 
pears. Codling moth and mites are lesser 
problems but bear watching. Fireblight can be a 
problem but so far has not seemed as severe as 
with Bartlett and Bosc. 

Harvest . Harvest times in our area have 
not yet been established but there are several 
cultivars available that Hkely will ripen in 
September and October. (Note: To begin 
obtaining some information, such as harvest 
dates, the three regional fruit agents in 
Massachusetts are establishing Asian pear 
cultivar trials including about 10 to 12 trees on 
a site. Growers who are interested in being 
involved in this study are urged to contact one 
of the regional agents.) When harvesting Asian 
pears care must be taken, because scarring and 
bruising can occur very easily. Fruit should be 
picked into Hned baskets. Yields in California 
range from 150 to 200 pounds per 8- to 10-year- 
old tree. 

Storage . Most Asian pears can be stored 
for up to 6 months at 32°F, although some 
cultivars store better than others. So far, 
extended storage has not been required to a 
great degree in California, since market demand 
has remained high early in the season. 



14 



Market . A New England market for Asian 
pears has already been established by Western 
U.S. fruit marketers, but it is felt that a few 
enterprising local growers could find a niche in 
our markets for this group of fruits. 



Information for this article came from 
Fowler Nurseries, Newcastle, CA, and from 
articles in HortScience (15:13-17) and California 
Agriculture (W. H. Griggs and B. T. Iwakiri. 
January, 1977). 



*^k 4t ^t# ^b 

*J* ^^ *(* •p 



VARIABLE CONDITIONS IN CA STORAGE CAN 
CAUSE FRUIT DISORDERS AFTER STORAGE 

William J. Bramlage 

Department of Plant and Soil Sciences, University of Massachusetts 



We frequently receive samples of fruit after 
storage which contain some disorder(s), and are 
asked what caused the problem. Even when we 
see a copy of the storage log, it is often difficult 
to specify the problem. We can usually identify 
the disorder, but pinpointing its cause is often 
little more than a guess, because storage (and 
prestorage) conditions often interact to produce 
problems. 

This interaction of conditions was addressed 
in a recent paper by C. R. Little and I. D. Peggie 
of the Horticultural Research Institute, Victoria, 
Australia {HortScience 22(5):783-790). The paper 
reported results from an extraordinarily complex 
series of experiments that spanned 8 years and 
included 7 cultivars of apples and 2 cultivars of 
pears. All fruit were harvested preclimacteric and 
were stored in small experimental chambers where 
conditions could be carefully controlled. 

The primary objective was to test various 
I0W-O2 regimes. In this experiment, they 

compared Conventional CA (2 to 5% CO2 and 2 to 
5% O2, depending on cultivar). Ultra-low O2 (1% 
CO2 and 1.5% O2), and Hyper-low O2 (0.5% CO2 
and 0.7 to 1.0% O2). They also applied Initial 
L0W-O2 Stress (less then 0.2% O2 and less than 
2% CO2 for the first 10 days of storage), followed 
by one of the other I0W-O2 systems. In addition 
to comparing the various O2 regimes, they 
examined the interaction of Rapid CA (at- 
temperature 1 day after harvest and at- 
atmosphere in less than 6 days after harvest), 



Slow CA (at-atmosphere 14 to 20 days after 
harvest), inappropriate temperatures, high CO2 
levels, and ethylene scrubbing. 

Results were judged in terms of the 
percentages of disorders that occurred, primarily 
scald, Hesh browning, and core flush (a disorder 
somewhat similar to brown core in Mcintosh). 
Most of the experiments were with Jonathan and 
Granny Smith apples. 

Among the findings of the study were these: 

1. The lower the O2 level, the less scald 
developed. However, below a certain O2 
level (depending on cultivar), the percents of 
flesh browning and core flush increased. At 
these levels, off-flavor and purpling of the 
skin were noticeable in some cultivars. 

2. Very low levels of O2 at the beginning of 
storage were effective when Rapid CA was 
used, but caused disorders when Slow CA 
was used. Also, the Initial L0W-O2 stress 
caused disorders if it lasted more than 10 
days. 

3. If the atmosphere was changed part-way 
through storage, it was beneficial if it 
beoune less severe but was detrimental if it 
became more severe. The change was more 
consequential if it occurred at 100 days than 
if it occurred later than this. 



15 



4. When temperature was kept either above or 
below what was recommended for a cultivar, 
greater amounts of disorders occurred. If the 
incorrect temperature was combined with low 
O2, the effect was made worse. 

5. Disorders that were intensified by very low 
O2 and by low temperature were made worse 
when CO2 was too high. The worst situation 
was when very low O2 was combined with 
both too low a temperature and too high a 
CO2 level. All 3 factors interacted to worsen 
problems. 

6. Ethylene scrubbing reduced disorders, 
especially scald. However, either 6% CO2 or 
extremely low O2 levels were just as effective 
as ethylene scrubbing in controlling scald. 

7. When CO2 was higher than O2 in a storage 
atmosphere, disorders tended to be increased. 
Low O2 and high CO2 interacted to intensify 
disorders other than scald, but the presence 
of ethylene did not make these problems 
worse. 

The technology involved in these studies 
generally is not applicable in the Northeast fruit 
industry today. However, the principles that are 
seen in the results are meaningful. 

Clearly, anyone wishing to modify standard 
storage recommendations must do so with great 
care. Lowering O2, increasing CO2, or lowering 
temperature possibly can reduce fruit softening, 
but any of these factors can also lead to 
disorders: low O2 injury, high CO2 injury, or 
brown core. Thus, each modification involves a 
calculated risk. What is generally not recognized 
but is made dear in these studies is that if one 
factor is changed (e.g., O2 is lowered), the risk 
of damage from the change is greatly increased if 
temperature is also changed or CO2 is also raised, 
or worst of all, if all 3 modifications occur. 
Most often, these additional changes are not 
intended but result from operator errors or 
equipment malfunctioning. The less reliable and 
accurate that storage operation is, the greater is 
the risk of a detrimental result if a storage 
condition is deliberately modified. 

The corollary of this situation is: if a 



storage operator wants to modify standard 
recommendations, storage management must first 
be made precise and accurate. It is hazardous 
to modify storage conditions without fu-st making 
certain that storage operations are precise. If 
you want to modify one condition, you must be 
able to control other factors so that a stressful 
combination of factors can be avoided. 

Should a storage operator discover that 
adverse conditions have developed, he should 
react by lessening the stress on the fruit. For 
example, he may be operating at a less-than- 
recommended O2 level when he discovers that 
CO2 is creeping out of control. Since he is 
losing control of CO2, he needs to increase the 
O2 to avoid a double stress. The sooner this is 
done, the less likely it is that damage will 
result. 



Little and Peggie concluded that percent 
CO2 should not exceed percent O2 in a storage 
atmosphere. We recommend 5% CO2 and 3% O2 
for Mcintosh, which appears to violate their 
conclusion. However, ours is a very conservative 
recommendation for Mcintosh, recognizing the 
lack of sophistication in operation of most of 
our storages, and is outside the consideration of 
these authors. Yet, it is probably a good rule- 
of-thumb that should you lower O2 below the 
standard recommendation, you should follow 
Little and Peggie's advice: keep CO2 lower than 
O2. 

The results of this study emphasize that 
storage operation is a system , in which O2, CO2, 
and temperature are in balance. Preharvest 
conditions, fruit maturity, speed of atmosphere 
generation, and possibly ethylene enter into this 
balance. Our standard storage recommendations 
are deliberately conservative to allow for some 
variability among these factors. If a storage 
operator chooses to modify these 
recommendations, he must be able to control the 
other factors in this balance, so that multiple 
stresses do not result. Unless he can provide 
this control, he should not deviate from the 
standard recommendations unless he is prepared 
to accept possibly serious development of 
disorders in fruit during and after storage. 



*4f '^ *t> ^b 

^^ •^ w^ ^^ 



16 



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Cooperative Market Pooling for Small Scale Production 
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Economics of Small Scale Food Production 



Varieties of Apples For Massachusetts 

Varieties of Peaches for Massachusetts 

Varieties of Pears and Quinces for Massachusetts 

Varieties of Plums for Massachusetu 

Apple Spray Guide 

Integrated Management of Apple Pests in Massachusetts 

Peach, Pear, and Plum Guide 

Pruning Tree Fruit 

Pruning Neglected Aging Apple Trees 

Rejuvenating Mcintosh Apple Orchards: 

Response to Reduced Alar 
Topworking and Budding of Fruit Trees 
Ladder Safety in the Orchard 
Be a Better Apple Picker 
Harvesting Suggestions for Orchard Foremen 
Home Orchard Peach and Nectarine Culture 



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Strawberry Diseases 

Strawberry Pest Management Schedule 



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Pruning Blueberries 

Varieties of Blueberries for Massachusetts 

Blueberry Diseases 

Blueberry Pest Management Schedule 



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Bramble Pest Management Schedule 



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Varieties of Grapes for Massachusetts 

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Fruit Notes 

Prepared by the Department of Plant & Soil Sciences - . ^^O'^Orr'^ /» 

' ■ '■-■' . ■"C- 

University of Massachusetts Cooperative Extension, " ' ^ O 

United States Department of Agriculture, and Massachusetts Counties cooperating. ^PR ^ C) looq 



ISSN 0427-6906 



Editors: Wesley R. Autio and William J. Bramlage 



SCitivjj^ 



^^^ti^iii 



Volume 53, Number 2 
SPRING ISSUE, 1988 




Table of Contents 



Summer Pruning is Important for 
Early Harvest of High Quality Mcintosh 

A Brief History of the Cultivated Strawberry 

The Initiation of a New IPM Program in Strawberries in 
Massachusetts: Accomplishments in the Pilot Year 1987 

Benefits of Alar to Apple IPM Programs 

Results of the First Year of Second-stage Apple IPM Practices 

Singing in the Rain: The Effects of Weather on Plum Curculio 

Spring Migration 



A Comparison of Insecticidal Soap and Amitraz as Summer Sprays 

Against Pear Psylla 

A Report on the 1987 Massachusetts Apple IPM Program 



Fruit Notes 

Publication Information: 



Fruit Notes (ISSN 0427-6906) is published the first day of January, 
April, July, and October by the Department of Plant & Soil Sciences, 
University of Massachusetts. 



The costs of subscriptions to Fruit Notes are $4.00 for United States 
addresses and $6.00 for foreign addresses. Each one-year subscrip- 
tion begins January 1 and ends December 31. Some back issues are 
available for $1.00 (United States addresses) and $1.50 (foreign 
addresses). Payments must be in United States currency and should 
be made to the University of Ma.ssachusetts. 



Correspondence should be sent to: 

Fruit Notes 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

University of Massachusetts 

Amherst, MA 01003 



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SUMMER PRUNING IS IMPORTANT FOR EARLY 
HARVEST OF HIGH QUALITY MCINTOSH 

Duane W. Greene and Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 



Summer pruning is a useful technique for increas- 
ing red color and allowing early harvest of Mel ntosh apples, 
as we have previously reported (Fniit Notes 52(3):7-8). 
Most researchers conclude that August is the best time to 
summer prune. It is reasoned that at this time rcgrowth 
following summer pruning will be minimal, there will be 
little risk of encouraging winter injury, and it will not be too 
late to enhance color development. The goals of our 
research in 1987 were to confirm the benefits of summer 
pruning and to evaluate the potential for expanding the 
timing of summer pruning to include .inly. 

Dormant Pruning is Neccss:irv . Previously we 
emphasized the need for proper dormant pruning to 
achieve the maximum benefits from summer pruning 
(Fm/VA'oto 53(1): 12-13). Large branches in the tops of the 
trees that cause shading must be removed during the 
dormant season, because removal during the summer 
causes too much fruit damage and drop as cut branches fall 
through the tree canopy. A program of limb rotation in the 
tops of trees should be conducted in the dormant season to 
maintain a conically shaped tree and to assure that there 
are no major obstacles to light penetration into the tree 
canopy. 

Summer Pruning Procedure . Summer pruning 
cuts should maximize light penetration. (Jcneraliy, these 
are made in the tops and on the periphery of the tree. 
Specific suggestions are listed below. 

1. Remove vigorous, upright branches that will not be 
productive. 

2. Remove weak, hanging branches that are shading 
productive wood below them. 

3. Remove watersprouts; however, leave a sufficient 
number with wide crotch angles to serve as potential 
replacements for large branches in a limb rotation pro- 
gram. 

4. Do not remove branches larger than 1 inch. 

5. Use thinning cuts rather than heading cuts, since 
thinning cuts generally will result in less unwanted re- 
growth. 



Research Results in 1987 . In June 90 mature 
Mclntosh/M.7 trees were selected and distributed among 
15 groups of 6 trees each. One tree in each group was not 
summer pruned and served as a control. Each of the 
remaining 5 trees in each group was summer pruned on 
eitherJulyl, July 15, August 4, August 14, or September 1. 

The first harvest in this block was on September 
15. Twelve percent more fruit were picked from summer 
pruned trees at this harvest (Table 1). A random sample 
of fruit taken immediately before harvest showed why this 
effect occurred: summer pruning resulted in 10% more red 
color and 30% more fruit making the U.S. Extra Fancy 
grade (Table 1). There were no detrimental effects ob- 
served due to summer pruning. Additionally, it appeared 
to make no difference when the trees were summer pruned, 
i.e. similar benefits were obtained from all treatments. 
However, it should be noted that it took longer to prune 
each tree as the sea.son progressed, 11 minutes per tree on 
July 1 and 16 minutes per tree on September 1. 

The results reported here have important prac- 
tical significance. The beneficial effects ofsummer pruning 
on red color and packout again have been confirmed. 
Additionally, more fruit may be picked in the early portion 
of the harvest season when they have the maximum storage 
potential. Furthermore, summer pruning may be done 
equally well any time during the months ofJuly and August. 
Therefore, growers may summer prune trees during slack 
periods using existing help, or it may be advantageous to 
bring in off sht>re labor early, specifically to summer prune 
Mcintosh trees. 



Table 1. Effect 


s ofsummer 


pruning in 


1987. 






Red 


U 


. S. Extra 


First 




color 




Fancy 


harvest 


Treatment 


(%) 




(%) 


(%) 


Control 


52 




44 


43 


Julyl 


61 




71 


53 


July 15 


62 




76 


55 


August 4 


64 




76 


57 


August 14 


64 




89 


54 


September 1 


61 




73 


55 


1 



A BRIEF HISTORY OF THE CULTIVATED STRAWBERRY 



David T. Handley 

Cooperative Extension Service, University of Maine 



The cultivated strawberry, Fragaria ananassa 
Duch., is a relative newcomer to agriculture. The cullivars 
now grown arc the result of hybridization by humans, the 
fruit being quite different from those of their natural 
ancestors. The unique developmental nature of the fruit 
has made it the center of much study. The plant itself also 
presents features of interest in its vegetative reproductive 
ability, and its response to environmental conditions. In a 
more practical sense, the strawberry has become the basis 
of a large commercial industry, and is considered to be the 
most popular small fruit in the United States. 

The exact origin of the modern cultivated straw- 
berry is unclear, but the best evidence indicates that it is 
derived from a cross between two native American species, 
F. virginiana Duch., andF. chilocnsis Linn. The former is 
a common inhabitant of the eastern coast of North Amer- 
ica that greatly impressed early seventeenth century colo- 
nists. The natives commonly used the fruit in breads, but 
Roger Williams noted in 1643 that "the English have 
exceeded and make good wine". The species was intro- 
duced in England, and soon became a favorite in local 
gardens. 

Prior to these introductions, the prevalent 
strawberry in England and Europe was F. vesca Linn., 
commonly known as the wood strawberry. This berry has 
a history dating back to the Romans, who favored it served 
with cream and sugar, or soaked in wine. It is doubtful, 
however, that the plant was widely cultivated at that time. 
Supplies were probably obtained from the plentiful popu- 
lations growing wild. By the fifteenth century, large-scale 
cultivation of this species was occurring, but it was eventu- 
ally replaced by an early-ripening, bright red clone of F. 
virginiana , developed from the slock originating in the 
colonies. 

In 1712, while gathering information about 
Spanish fortifications along the west coast of South Amer- 
ica for the French navy, Captain Amede Frezier was 
impres.sed by the large-fruited strawberries cultivated by 
the natives. Being an amateur botanist in addition to a spy, 
he collected some plants for the voyage home. Two of the 
few surviving specimens were given to the Royal ( Jarden in 
Paris along with the .statement that they bore fruit "as big 
as walnuts". Antoinc de Jussieu, director of the garden at 
the time, must have been disappointed when the plants 



produced only small, deformed berries if any. 

The plants Frezier took back to France were F. 
chilocnsis. This species is dioecious (requiring both male 
and female plants for productivity), and unfortunately he 
had collected only females. The problem was simply a 
matter of pollination, but this fact apparently was not 
realized until many years later. Fortunately, plants were 
retained in some collections and the species was later 
redeemed when in Brittany it was discovered that inter- 
planting it with F. virginiana , a plentiful pollen producer, 
resulted in excellent crops. F. cliiloensis, or the Chilean 
strawberry, soon became the major species of commerce. 
Brittany was the European center of production, shipping 
fruit to Paris and London. Despite its impressive size, 
however, this strawberry was pale, seedy, and faint of 
Havor. 

Probably as a result of the cross pollination 
technique used to produce Chilean strawberries, seedlings 
of F. chilocnsis x F. virginiana crosses began to appear in 
European gardens. Some of this progeny bore fruit of large 
size with a deep red ficsh. The Havor was somewhat 
reminiscent of pineapple, and for this reason these plants 
became known as the pineapple strawberry or pine straw- 
berry. Although the origin was initially clouded, probably 
by businessmen in hopes of high profits, Antoinc Nicholas 
Duchesne published a hypothesis of its hybrid origin in 
1766, based upon his experier.ce with strawberry breeding 
and knowledge of the Brittany practices. The pine straw- 
berry was named F. ananassa Duch. 

In America, the early commercial strawberry 
industry was dependent upon the European introductions 
ofF. virginiana and F. ananassa. However, in 1838, Charles 
Hovey, of Cambridge Massachusetts, introduced the 
'Hovey' strawberry. This cultivar was the result of crossing 
a European pine strawberry with a native F. virginiana. 
'Hovey' is credited with being the first cultivar of any fruit 
made from an artificial cross in the United States. The high 
quality of both the fruit and plant stimulated a great new 
interest in strawberries throughout the country. This 
cultivar and later U. S. introductions such as 'Wilson' and 
'Howard' provided the basis for future breeding programs 
and led to the large and successful commercial industry we 
know today. 



References 

Darrow, G. M. 1966. Vie Strawberry: History, Breeding, Hendrickson, R. 1981. Tlie Berry Book. BaWcnUnc. NY. 
and Physiology. Holt, Rhincharl, and Winston. NY. 

Wilhelm, S. and J. E. Sagcn. 1974. A History of the 
Hcdrick, U. P. 1925. Tlie Small Fniits of New York. Rept. Strawberry. Univ. Cal. Berkley, CA. 
N. Y. Agric. Exp. Sta. J. B. Lyons Co. Albany, NY. 



*4fi 4fi ^fe ^^ 

n^ ^re wn ^u^ 

THE INITIATION OF A NEW IPM PROGRAM IN 
STRAWBERRIES IN MASSACHUSETTS: 
ACCOMPLISHMENTS IN THE PILOT YEAR 1987 



Sonia Schloemann and Daniel Cooley 

Department of Plant Pathology, University of Massachusetts 



Strawberries are the most extensively planted 
small fruit in Massachusetts. According to current esti- 
mates by the Massachusetts Department of Food and 
Agriculture there are approximately 500 acres of strawber- 
ries grown commercially in the state. The estimated yearly 
value of the crop is $5,000 per acre for an overall value of 
approximately $2.5 million. An individual's actual crop 
value is determined largely by the marketing methods used 
and the price that he is able to obtain. It is clear, however, 
that strawberries are a valuable crop and can provide 
significant returns under the proper conditions. 

Most Massachusetts growers do not produce 
large acreages of strawberries. The average grower man- 
ages 3.5 acres, which illustrates the fact that strawberries 
are often used as a cash crop to augment the income from 
other fruit or vegetable crops. Strawberries fit in well with 
these other cropping systems in terms of land require- 
ments, machinery needed, and timing of harvest. 

Strawberry culture requires significant inputs in 
production and pest control. The increased awareness of 
the ecological risks and the rising costs of pesticide appli- 
cation are putting a strain on Massachusetts growers and 
are providing incentives for developing new management 
strategies. Additional incentives include: the development 
of resistance by pests and pathogens to certain pesticides; 
the loss of registration of some pesticides because of 
potential health hazards; and, the risk of exposure by the 
public to the spray materials used in commercial straw- 
berry production. This danger is enhanced by the fact that 



most of the berries are sold on a pick-your-own basis, so 
consumers may be exposed to pesticide residues in the 
field. 

With this situation as a backdrop, the Strawberry 
IPM program embarked on its first season with a set of 
objectives as stated in the Summer, 1987 issue ofFntit Notes 
(6). To summarize these objectives, we sought to: (1) 
identify the key pests causing economic injury to straw- 
berries in Massachusetts; (2) establish consistent and 
accurate sampling techniques for each key pest; (3) study 
available management and control methods; (4) deter- 
mine what the current pest control practices are and the 
areas for potential change; (5) conduct trials using alter- 
native fungicide spray recommendationsand evaluate their 
efficacy; and (6) distribute a regular Strawberry Pest 
Message. Efforts to address these objectives were made in 
several ways: (1) surveys were conducted at 4 locations on 
a weekly basis throughout the season to monitor pest 
pressures; (2) observations were made at 10 additional 
locations; (3) sampling methods for all pests were devel- 
oped and evaluated at these locations; (4) scouting results 
were reported weekly through harvest and occasionally 
thereafter; (5) limited-fungicide spray recommendations 
were made and evaluated; (6) literature searches were 
conducted to determine the current stale of knowledge on 
strawberry pest management; and (7) all Massachusetts 
strawberry growers were surveyed to obtain information 
on current practices and concerns. The results of these 
efforts follow. 



Strawberry Pests 

Pest control in strawberries includes efforts in all 
three pest groups: insects, diseases, and weeds. Key insect 
pests, those which cause economic injury and concern to 
the grower, include tarnished plant bugs {Lyf^ts Uncolaris), 
strawberry bud weevils (clipper) {Anlhonoinus sigiwtiis), 
and two-spotted spider mites {Tetranychus iirticac) (12). 
Other insect pests exist but arc of lesser concern togrowers. 

Important plant disease organisms include bacte- 
ria, viruses, and fungi, with fungi being the most prevalent. 
Fungal pathogens fall into four categories: berry rots, leaf 
diseases, crown rots, and root rots. The two key diseases 
of concern are a berry rot, grey mold {Botrs'tis cincrca), and 
a root rot, black root rot {Rhizoctonia fragaria) (12). Red 
stele (Phylophthora fragaria) is also a problem in the 
Northeast but generally is managed successfully through 
the use of resistant cultivars and soil fumigation. 

Keystrawbcrryweeds vary widely throughout the 
state but grasses and other perennial weeds are of most 
concern. These weed problems include dandelion {Ta- 
raxacum officinale), goldenrod (Solidago canadensis), 
orchard grass {Dactylis gloinerata), quackgrass {Agropyron 
repcns), and yellow wood sorrel (Oxalis siricta) (12). Heavy 
weed infestations will affect yield, plant vigor, and bed 
longevity. 



Key Insect Pests 

Tarnished plant bug causes misshapen berries 
with the typical "cat-facing" or apical seediness. It is 
ubiquitous and can cause severe losses of yield if not 
controlled. The damage is caused by the feeding of adults 
or nymphs on the newly developing fruit. Feeding prevents 
individual achenes from developing, thus causing the de- 
formity. The later in the development of the berry that 
feeding occurs, the less significant the injury. However, 
under heavy infestations, 30 to 50% crop reductions have 
been reported (10). Current practices include 1 to 3 sprays 
in the early season with malathion or thiodan. 

Tarnished plant bugs overwinter as adults and lay 
eggs in early May. Eggs hatch at approximately the same 
time as the strawberries are approaching 10% bloom. The 
nymphs cause the majority of the damage and must be the 
target of a management plan. Sampling for these nymphs 
may be done by shaking 25 flower trusses from a 2-foot 
section of row individually over a dish at a number of 
locations. The current threshold number usingthis method 
is 1 nymph per 25 flower trusses (10). We were unable to 
evaluate this method satisfactorily in 1987, because the 



IPM program began at the end of the flowering period. A 
second monitoring method that we tried was the use of 
sticky traps to catch the adult tarnished plant bugs, as has 
been shown in apple orchards (4). This procedure was not 
satisfactory, because it was difficult to correlate trap 
catches and damage and to set threshold levels. The use of 
models for egg hatch and nymphal development according 
to thermal accumulation has been studied in Quebec (1) 
and may prove useful in combination with sticky traps for 
determining first incidence of tarnished plant bug activity. 
The Massachusetts Strawberry IPM Program will be using 
the Hower truss/nymph method this year to make spray 
recommendations based on threshold numbers. The ob- 
jective is not only to reduce the number of sprays but also 
to improve the liming of sprays and to fine-tune the rates 
and materials used against tarnished plant bug. 

Strawbcrrvbud weevil causes a reduction of yield 
by laying eggs in the newly exposed buds and girdling the 
pedicel of these buds, which then will not develop. This 
pest, otherwise known as the clipper because of the nature 
of the injury, is not as common in Ma.ssachusetts as is the 
tarnished plant bug, but when it occurs, it can cause severe 
losses; up to 90% damage has been reported in some states 
(11). Current practices include 1 to 3 pre-bloom sprays per 
season of guthion, parathion, or lorsban. 

The strawberry bud weevil overwinters as an adult 
in hedge-rows or woods and is active when temperatures 
are above 60°F and buds are available. Sampling for this 
pest is performed by counting the number of clipped buds 
per 2 feet of row. Unfortunately, this procedure counts the 
damage after the fact but is the only satisfactory method 
available. The threshold number that we are currently 
using is 1.2 clipped buds per 2 feet of row (11). Samples 
should be taken from near the field borders, hedge-rows, 
and woods since these arc areas where we expect to find the 
clipper first, and we want to halt the invasion of it into the 
field. When the threshold level is reached, we recommend 
spraying with guthion at labeled rates. As with the tar- 
nished plant bug, the objective not only is to reduce the 
number of sprays but to improve effectiveness by improv- 
ing the timing. Experiments are planned to aid in the 
development of a trap or lure similar to that used for the 
boll weevil, so that we can monitor populations before 
damage occurs. 

Two-spotted spider miles affect the yield of straw- 
berries indirectly by sapping the vigor of the plants. These 
tiny arthropods live on the underside of leaves and feed on 
plant juices. Under heavy infestation (over 100 mites per 
leafiet) two-spotted mites can have significant impacts on 
yields and on the longevity of a bed (9). Many growers do 
not spray for two-spotted mites because their heaviest 



populations occur during harvest. Spraying during this 
time is not recommended and growers can wait and get 
adequate control simply with renovation when the foliage 
is mowed off. However, for growers who feel they must 
spray before harvest or after renovation one or two sprays 
of kelthane or plictran may be used. Both of these 
materials were removed from the market during 1987, but 
some formulations of kelthane are available for use in 1988. 

Two-spotted spider mites overwinter as adults 
and become more active as temperatures increase during 
the summer. Dry, hot weather favors these mites. There 
is a danger that populations can explode in a very short 
period of time. The strawberry 1PM program is refraining 
from making recommendations for mile control based on 
threshold numbers, because there is little agreement 
among researcherson what population levels are tolerable. 
We will, however, report levels to growers. The current 
concern is the lack of availability of milicides for those 
growers who want to control mites. We plan to explore the 
use of biological control of two-spotted mites with the use 
of indigenous predacious mites (Anihlysciiis fallacis) (8). 
This type of control can be accomplished cither by encour- 
aging the growth of natural populations of these predators 
or by the release of artificially-reared populations to aug- 
ment the naturally occurring ones. In addition, the use of 
"soft" pesticides such as insecticidal soaps, which have 
been successful in greenhouse settings, will be evaluated 
for efficacy in strawberries during 1988. 



normally used from bloom through harvest. 

In Ontario, grey mold has been shown to overwin- 
ter in the green leaf tissue under the winter mulch (2). This 
fact, if it is also true in New England, has significant 
implications for disease management. According to the 
Ontario work, spores from infected crop residues land on 
newly formed and expanding leaves in the fall. The spores 
germinate and invade the leaf tissue and then enter a 
quiescent state for the winter protected by the winter 
mulch. At that time there are no visible symptoms of 
infection. Then, in the spring when these leaves begin to 
sencsce and die, the fungus grows and produces new spores 
which are available to infect the tender blossom petals, 
which then infect the fruit. Using this information, one can 
protect the leaves from infection in the fall or knock back 
the initial inoculum in the spring before the blossoms 
appear. This treatment eliminates the need for numerous 
sprays, and the potential for any fungicide residues on the 
fruit. Since no developing fruit will be present at the time 
of sprays, they cannot accumulate fungicide (13). Leaf 
protection can be accomplished by applying fungicides to 
the surface or by providing competitive organisms which 
will inhibit the ability of the fungus to germinate or pene- 
trate the surface of the leaf tissue (5). Two yeast species and 
one bacterial species which occur naturally on the surface 
of strawberry leaves and provide effective biological con- 
trol of grey mold in Ontario have been identified (13). The 
Strawberry IPM program is determining the efficacy of 
these methods in Ma.ssachusetts. 



Key Disease Organisms and Their Damage 

Grey mold (Botrylis cinerea). This fruit rot is, by 
far, the problem of most concern to Massachusetts growers 
in terms of potential for yield reduction (12). The Botrytis 
fungus infects the Hower petals or sepals and then prolifer- 
ates in the developing fruit causing it to rot. The berries 
may rot on the plant or shortly after they have been 
harvested. Grey mold can cause very heavy losses in years 
with damp wet weather in the spring, especially if it occurs 
during bloom. If not managed, under these conditions a 
nearly complete crop loss is possible. Even under a 
fungicide spray program a significant yield reduction may 
occur. Current practices include 1 to 12 sprays per season 
with captan, benlate, captan/benlate, or ronilan. 

During 1987 an IPM spray regime consisting of 3 
bloom sprays of captan or ronilan was compared with a 
typical spray regime. We found no significant difference in 
the amount of berry rot found with either regime (12). 
These results concur with work done by other researchers 
(3) and suggest that 3 well-timed bloom sprays are as 
effective for grey mold control as the 4 or more sprays 



Grey mold management presents a major chal- 
lenge to pesticide reduction strategies. We are targeting a 
reduction in the number of sprays, adjusting spray timing 
to early season, and exploring the potential for biological 
alternatives to reduce the pesticide load on the environ- 
ment. Our approach is especially timely since captan's 
registration is under special review and grey mold has 
developed resistance to benlate and ronilan in some areas. 
Furthermore, benlate has been shown to adversely affect 
populations of predacious mites in apples and may do the 
same in strawberries. 

Black root rot is a complex of organisms which 
results in the decay and blackening of the perennial and 
feeder roots. The causal fungus, RItizoctonia fragariae 
(Ceratobasidium sp.), commonly is associated with straw- 
berry roots. R.fragariac invades strawberry roots by direct 
penetration, causing cortical decay and rootlet death. This 
injury results in reduced plant vigor, and degeneration and 
premature death of plants. 

Black root rot is difficult to manage with existing 
measures. In Massachusetts, we suggest planting in well- 



drained soil, using "healthy" plants, mulching to reduce 
winter injury (a contributing factor), and using soil fumi- 
gants before planting. While these fumigants may help 
black root rot management, traces of them may also end up 
in underground water supplies. 

The IPM program plans to evaluate the use of 
reduced rales of standard fumigation materials, the effect 
of certain cover crops for reducing inoculum in the soil, and 
the possible use of biological control methods by inoculat- 
ing the roots at transplanting with avirulcnt strains of 
Rhizoctonia. This work has been initiated by Janice 
Drozdowski and Dr. William Manning at the University of 
Massachusetts (7). 



Weeds in Strawberries 

Weed control in strawberries poses one of the 
greatest challenges to commercial strawberry growers. 
Since strawberries are a perennial broadlcaf plant, man- 
agement of other perennials, particularly grasses, is diffi- 
cult. If weeds proliferate they can significantly shorten the 
longevity of a planting, reduce yields, and discourage pick- 
your-own customers from picking in certain areas. Sev- 
enty-seven percent of Massachusetts strawberry growers 
use herbicides, as compared to 70% who use fungicides, 
64% who use insecticides, and 28% who fumigate (12). The 
average number of herbicide applications for those who 
use herbicides is 3.2 sprays per season. This use level is 
more than that for most other crops. 

This year the IPM program surveyed strawberry 
plantings throughout the state to establish which weeds and 
weed types posed the most problems to growers. This work 
will continue in 1988 to provide a more complete picture of 
the situation. The strawberry IPM program plans to 
establish field plots to evaluate alternative weed manage- 
ment .strategics using reduced rates of certain herbicides 
and using certain mulching practices. The objective is to 
develop a management program with fewer herbicide 
applications without reducing yield and bed longevity. 



Conclusions 

Integrated pest management of strawberry has 
great potential forseveral reasons. First of all, strawberries 
suffer important damage from diseases, weeds, and insects. 
Secondly, pesticide applications are expensive both eco- 
nomically and ecologically. Also, several of the key pests 
of strawberries are significant pests in other crops and have 
been studied in the IPM context before, and this informa- 
tion gives us a head start in strawberry IPM. In addition, 



many of our Massachusetts growers are involved in or 
familiar with other Massachusetts IPM programs, i.e. corn, 
potatoes, or apples. The success of these programs has 
paved the way for an enthusiastic reception by growers to 
the Strawberry IPM Program. 

The first season of the Strawberry IPM program 
has been one of establishing baselines for current practices 
and knowledge of pest control, testing our scouting meth- 
ods and making some trial recommendations, and for 
introducing ourselves to the Massachusetts growers. The 
key to success of the strawberry IPM program is involve- 
ment of the growers, because their input is instrumental in 
directing the course of this program. 

We will be expanding our grower base from 4 in 

1987 to 15 in 1988. With a larger number of growers, we 
hope to be able to generate more information. We are 
particularly interested in how well the relatively untested 
techniques described in this paper will work in the field. 
Our new reporting forms will facilitate communication 
with growers. These forms will be used to report togrowers 
the scouting results for the week and recommendations 
based on those results. We look forward to a successful 

1988 season. 



Literature Cited 

1. Bostanian, N. J., G. Mailloux, and M. Binns. 1987. 
Modeling tarnished plant bug, (Lygiis lincolaris), nymphal 
populations in strawberry fields by thermal summation. 
Paper delivered at the 1987 Entomological Society of 
America Annual Meeting. Boston MA., November 29 - 
December 3, 1987. 

2. Braun, P. G. and J. C. Sutton. 1987. Inoculum 
sources oi Botrytis cincrca in fruit rot of strawberries 8in 
Ontario. Can. J. Plant Pathol. 9:1-5. 

3. Bulger, M. A., L. V. Madden, and M. A. Ellis. 1987. 
Infiuence of temperature and wetness duration on infec- 
tionof ripe strawberry fruit by fiof/}'//.rc//i<?re(7. Can. J. Plant 
Pathol, (in press). 

4. Coli, W. M., T. A. Green, T. A. Hosmcr, and R. J. 
Prokopy. 1985. Use of visual traps for monitoring insect 
pests in the Massachusetts IPM program. Agric. Ecosys- 
tems Environ. 14:251-265. 

5. Cook, R. J. and K. F. Baker. 1983. Vie Nature and 
Practice of Biological Control of Plant Pathogens. Amer. 
Phytopath. Soc, St. Paul, MN. 



6. Coolcy, D. R., K. Hauschild, and S. G. Schlocmann. 
1987. A new program for integrated pest management of 
strawberries in Massachusetts. Fniit Notes 52(3):16-19. 

7. Drozdowski, J. L. and W.J. Manning. 1984. Straw- 
berry disease survey report. Unpublished manuscript. 

8. Oatman, E. R., F. E. Gilstrap, and V. Voth. 1976. 
Effect of different release rales of Phylosciiilus persimilis 
on the two-spotted spider mite on strawberry in southern 
California. Entomophaga 21:269-273. 

9. Oatman, E. R., J. A. Wyman, H. W. Browning, and 
V.Voth. 1981. Effects ofreleascs and varying infestations 
levels of the two-spotted spider mite on strawberry yield in 
southern California. 7. Econ. Entomol. 74:112-115. 



10. Schacffcrs, G. A. 1980. Yield effects of tarnished 
plant bug feeding on June-bearing strawberry varieties in 
New York state. J. Econ. Ent. 73:721-725. 

11. Schaeffers, G. A. 1981. Pest management systems 
for strawberry insects, pp. 377-393. In D. Pimentel (ed.) 
Handbook of Pest Management in Agriculture. Vol.3. CRC 
Press, Boca Raton, PL. 

12. Schloemann, S. G. and D. R. Cooley. 1987. Straw- 
berry IPM survey: 1987 program report. Report to the 
Massachusetts IPM Program. 

13. Sutton, J. C. and R. G. Braun. 1987. New Methods 
for controlling gray mould fruit rot (Botrytis cinerea) on 
strawberries. Proc. Ontario Hort. Crop Conference. 



*^M fc^^ ^^ *^* 

^K ^r ^^ ^t^ 



BENEFITS OF ALAR TO APPLE IPM PROGRAMS 

Ronald J. Prokopy 

Department of Entomology, University of Massachusetts 



Based on highly equivocal, unsubstantiated evi- 
dence, the U. S. Environmental Protection Agency (EPA) 
in August of 1985 announced the intent to cancel the 
registration of Alar^^ (daminozide). When the press heard 
of the EPA's intent to cancel Alar, the issue quickly 
received extensive national coverage, with ensuing strong 
condemnation of the material by the press and the public. 
Even though the EPA's ultimate decision was to reduce 
permissible levels of Alar on fruit, rather than cancel 
completely the use of Alar, the initial irresponsible an- 
nouncement of intent to cancel use was sufficient to flag 
Alar as a dangerous chemical in the mind of the public. The 
Massachusetts Department of Public Health expanded 
upon the original EPA announcement by phasing out 
tolerances for Alar residues in processed products. As you 
well know, the end result has been strong reluctance on the 
part of brokers, processing firms, and supermarkets to 
accept apples treated with Alar for fear that consumers 
would refrain from buying them. In turn, many growers 
were reluctant to use Alar in 1986 and 1987 for fear that 
they could not sell their apples, even though it technically 
has remained legal to use it. This nonuse resulted in 
premature drop of nearly 30% of all Mcintosh and reduc- 
tion in storability of those apples that were harvested. 



This situation in itself is most unfortunate. But, an 
equally great misfortune is the highly counter-productive 
effect discontinued use of Alar has had on present and 
potential integrated pest management (IPM) practices on 
apples. In regard to present practices. Alar is frequently 
used not only to positively affect fruit quality but also, when 
applied in mid-or late-June, to slow the growth of water- 
sprouts and terminals. A positive benefit of this use to pest 
management lies in depriving aphids of rapidly-growing 
foliar tissue. Hence, aphid populations tend to be lower in 
blocks treated with Alar in June. Another benefit of Alar 
to current IPM practices is associated with tolerable levels 
of leafmincrs and spider mite populations. When present 
in substantial numbers (and even in only moderate num- 
bers in dry years), leafmincrs and mites can cause prema- 
ture fruit drop, reduce fruit coloration, and diminish the 
keeping quality of fruit. Without Alar, many growers have 
had to use a greater amount of pesticide against leafmincrs 
and mites to maintain these pests at levels lower than can 
be tolerated in Alar-treated blocks. With Alar, we can 
tolerate more leafmincrs and mites to maintain these pests 
at levels lower than can be tolerated in Alar-treated blocks. 
With Alar, we can tolerate more leafmincrs and mites 
without ill effect. 



In regard to future IPM practices, particularly 
second-stage IPM practices, Alar (or another compound 
that is equally effective) must play a major role or else most 
second-stage practices will come to naught. In nearly all 
orchards treated with Alar, few pests can survive within the 
orchard itself because the fruit (and any pests the fruit may 
harbor) are picked before they drop. Thus, the pests are 
taken away with the fruit. When the fruit drop, however, 
pests may remain in the orchard, overwinter there, and 
pose an immediate threat to the crop next summer. The 
low price paid for dropped apples does not usually warrant 
investment of labor to pick them up, so many are left on the 
ground to rot. Such a situation is not amenable to manage- 
ment by a second-stage IPM approach of intercepting pests 
at the orchard border, before they enter the orchard. Thus, 
without Alar, growers are denied the opportunity of reduc- 
ing pesticide use against pest insects and mites by using a 
second-stage IPM approach, and are denied the opportu- 



nity of producing healthier, more pesticide-free apples. 

We feel the EPA and the Massachusetts Depart- 
ment of Public Health did not consider the multiple bene- 
fits of Alar to fruit growers and the environment when it 
announced in 1985, without good evidence, that Alar was 
a dangerous chemical. In truth, the EPA's decision not only 
has caused a great economic hardship to fruit growers, but 
also has been counter-productive to the EPA's own best 
interest in providing for a healthier environment. The 
EPA's 1985 announcement has and will continue to cause 
greater use of more toxic (but nevertheless legally used) 
pesticides than otherwise would be necessary with Alar. 
We hope that the EPA and the Massachusetts Department 
of Public Health in the future will consider more fully the 
positive benefits of an orchard chemical when making a 
cost/benefit analysis of the future use of a compound. 



* * * 



RESULTS OF THE FIRST YEAR OF SECOND-STAGE APPLE 
IPM PRACTICES 



Mary T. O'Brien and Ronald J. Prokopy 
Department of Entomology, University of Massachusetts 



Since 1978 we have conducted a program of 
integrated pest management (1PM) in Massachusetts 
apple orchards. The first-stage of this program, from 1978 
through 1982, was funded by a 5-year federal Cooperative 
Extension Service pest management grant to initiate a pilot 
IPM program. A maintenance phase followed the pilot 
program and has been ongoing since 1982. 

Initially, there were 3 major objectives: to pro- 
mote the buildup of natural populations of beneficial 
predators, to reduce pesticide use, and to maintain or 
increase the quality and quantity of fruit produced. The 
overall entomological approach to achieving these objec- 
tives was to intensively and carefully monitor abundances 
of pests and beneficial natural enemies in participating 
IPM orchards and to give advice to IPM growers as to the 
need for, optimal timing of, and type of pesticide to be 
applied. 



The results of this pilot program were highly 
encouraging. Compared with pesticide use before 1978, 
there was a 37% reduction in insecticide use and was a 61% 
reduction in miticide use during the pilot program, along 
with a reduction in the loss of fruit due to insect damage. 
The results were so encouraging, in fact, that 2 persons 
trained in the program formed "New England Fruit Con- 
sultants". Over the past 5 years (1983-87) they have been 
hired by commercial growers to provide IPM scouting and 
advisement services on more than one-third of the apple 
acreage in Massachusetts. 

Results of a recent survey indicated that about 
two-thirds of Massachusetts apple growers now employ 
IPM practices. Thus, over the past decade, this first stage 
of IPM in Massachusetts apple orchards can be considered 
a success, although this success must be tempered by the 
knowledge that the uses of miticides as well as non- 
selective insecticides directed against apple blotch leafmin- 



ers and white apple leafhoppers have been on the rise in 
IPM orchards over the past 5 years (partly due to develop- 
ment of resistance to materials previously effective). 
Having substantially achieved our goals, we initiated the 
second stage of the apple IPM program in 1987. 

Second-stage IPM employs behavioral, ecologi- 
cal, and biological approaches to pest management as 
substitutes for most pesticide treatments. The major goal 
of the program is to eliminate use of insecticides and 
miticides after the last curculio spray. This elimination 
allows important predators and parasites of key foliage- 
feeding pests (mites, aphids, leafminers, and leafhoppers) 
to build up to numberssufficient to provide control of these 
pests. To facilitate this goal, we emphasize the use, during 
April and May, of those pesticides least likely to be harmful 
to beneficial predators and parasites. 

In the summer of 1987, 18 commercial orchards 
participated in the second-stage IPM program comprised 
of the following 4 elements: 

(1) application of oil or other needed selective pesticides 

(1) during April and May to control European red mite, 
San Jose scale, tarnished plant bug, European apple sawfly, 
plum curculio, green fruitworms, and early-season leaf- 
rollers; 

(2) no use of any insecticide or miticide following the last 
plum curculio spray in May to permit buildup of beneficial 
predators and parasites in a pesticide-free habitat (except 
for fungicide use against diseases); 

(3) removal of abandoned apple, pear, hawthorn, and 
quince trees within 100 yards or more of the orchard 
perimeter to greatly reduce or preclude immigration of key 
mid- and late-season lepidopteran pests (codling moth and 
summer leafroUers) attacking apple fruit; and 

(4) intercepting apple maggot Hies (a key summer pest 
attacking the fruit) before the great majority of flies can 
penetrate the orchard interior, either by ringing the or- 
chard perimeter with odor/visual maggot Oy traps (sticky 
red sphercsbaited with synthetic apple odor) or by spraying 
perimeter-row apple trees periodically to kill entering files. 

Of the 18 blocks (2 to 4 acres each) there were 6 
in which odor/visual traps for apple maggot files were 
placed every 10 yards in the woods surrounding each block, 
6 in which odor/visual traps were placed every 10 yards in 
perimeter apple trees, and 6 in which perimeter apple trees 
were sprayed every 3 weeks during June, July, and August. 
We compared results in these blocks with a comparable- 
size nearby block in each orchard sprayed by growers in 



normal fashion during June, July, and August. 

Table 1 shows that on average 1,062 maggot files 
per orchard were intercepted in test blocks where traps 
were put in the woods, compared with 2,054 where the traps 
were placed in perimeter apple trees. One hundred 
percent more files were caught on nonbaitcd monitoring 
traps placed in interior apple trees in woods-trapped test 
blocks than in grower control blocks, suggesting that twice 
as many files were active in the interior of these test blocks 
than in the adjacent control blocks. About 46% more were 
caught on monitoring traps inside the apple-tree-trapped 
test blocks and 65% more in the border-row-sprayed test 
blocks than in the adjacent control blocks. Although none 
of the 3 approaches to intercepting maggot files before fiy 
penetration into the block interior was completely effec- 
tive, the latter 2 types gave promising results. 



Table 1. Apple maggot fiy captures per block. 



Type of block 



Interception Monitoring 
traps* traps** 



AMP traps in woods 1,062 

Grower control 

AMF traps in orchard 2,054 
Grower control 

Border row sprays 
Grower control 



352 
176 

123 
84 

104 
63 



*Odor-baitcd traps at orchard perimeter. 
**Nonbaitcd traps on interior apple trees. 



Table 2 shows the percent fruit damaged by each 
type of fruit-injuring pest. For all 3 test block types, 
combined injury by early season pests (plant bugs, sawfiies, 
curculios, and fruitworms) was greater in the test blocks 
than in the grower control blocks. These pests would have 
been controlled by sprays applied during April and May 
(prior to the start of the program). Hence, it appears that 
pest pressure in and around the average test block was 
greater than that in and around the average control block 
(so the cards were partly stacked against us). Maggot files 
caused about 4 times as much damage in woods-trapped 
test blocks as in control blocks (9.3 vs. 2.3%), about 3 times 
more damage in apple-tree-trapped test blocks as in con- 
trol blocks (1.4 vs. 0.5%), and about the same amount of 



Table 2. Fruit-injuring pests. 




Injured fruit 


(%)* 


TPB.EAS, 


** 


SJS,CM,LR 


Type of test block PC.GFW 


' AMF 


other 


AMF traps in woods 


14.0 


9.3 


2.4 


Grower control 


12.6 


2.3 


1.1 


AMF traps in orchard 


6.3 


1.4 


0.1 


Grower control 


2.3 


0.5 


0.2 


Border row sprays 


2.4 


0.6 


0.3 


Grower control 


1.9 


0.8 


0.3 


*700 fruit sampled per block ir 


July, August, and 


September. 








**Key: 








AMF -apple maggot fly 




PC -plum curculio | 


GFAV -green fruitworm 




SJS -Sa 


n Jose scale 


TPB -tarnished plant bug 


LR -Jc; 


frollcr 


EAS - European apple 


sawfly 


CM -codling moth 



damage in border-row-sprayed test blocks as in control 
blocks (0.6 vs. 0.8%). Damage by other mid- and late- 
season pests (scale, codling moth, leafrollers, and others) 
was about twice as great in woods-trapped test blocks as in 
control blocks (2.4 vs. 1.1%), but was no different in apple- 
tree-trapped and border-row-sprayed test blocks com- 
pared with control blocks. Although none of the test blocks 
yielded all perfect fruit, we feel these results are encourag- 
ing in terms of the potential effectiveness of either traps 
placed in perimeter apple trees, or border row sprays (in 
combination with removal of nearby host trees) as an 
alternative approach to managing maggot fly, codling 
molh, and leafrollers. 

Table 3 shows populations of foliar-feeding pests 
found during sampling in each block. Although popula- 
tions of European red mites and two-spotted miles aver- 
aged 37% higher in the test than in the control blocks, 
populations of mile predators averaged 137% higher in the 
test blocks. This result is precisely the sort of outcome we 
were hoping to sec. If (he test blocks were to remain free 
of inscclicidc and milicidc after May for the next 2 years, 
wc would expect mite predators to increase even further to 
a point where I hey alone (in conjunction wit hpre-bloom oil 
sprays) might be able to control pest mites. Woolly apple 
aphids were low in numbers in all blocks. White apple 
leafhoppcrs averaged 57% more abundant in the test 
blocks, but here again we expect leafhopper parasites to 



Table 3. Foliar-feeding pests. 


Type of test block 




Leaves (or 


terminals) 


infested (%)* 






ERM,** 
TSM 


Predatory 
mites 


WAA 


WAL 


PL 


ABLM 


AMF traps in woods 
Grower control 

AMF traps in orchard 
Grower control 

Border row sprays 
Grower control 


23 
20 

20 
13 

24 
16 


11 
4 

7 
4 

1 



1 
3 

2 
2 

5 
5 


13 

8 

9 

5 



1 


11 

8 

17 
10 

9 
10 




23 
12 

10 
14 

5 
4 


*200 leaves (or terminals) sampled per block in July and August. 

**Key: 

ERM -European red mite WAL -white apple leafhopper TSM 
PL -potato leafhopper WAA -woolly apple aphid ABLM 


-two-spotted mite 
-apple blotch leafm 


iner 





10 



increase in future years. Potato leafhopper averaged 32% 
more abundant in the test blocks, but we still have no solid 
evidence that this insect is truly injurious to bearing trees. 
Leafmincrs were 27% more abundant in the test blocks, 
but we fully expect leafminer parasites to increase to 
substantial levels during summer months in future years. 

Second-stage IPM research for 1988 will concen- 
trate on repeating the experimental designs for border row 
sprays and apple maggot traps placed in perimeter apple 
trees. The design which called for apple maggot traps in the 
woods around an orchard will be eliminated. 

In conclusion, results of the first year of implem- 
entation of several second-stage IPM practices in commer- 
cial orchards give us cause to be optimistic about the future 
of these practices in preventing injury to apple fruit during 
June, July, and August and in fostering buildup of impor- 
tant natural enemies of foliar pests. In succeeding years, we 
will work on refining our second-stage techniques (includ- 



ing possible substitution of sticky spheres with insecticide- 
impregnated non-sticky spheres), with the aim of being 
able to recommend with confidence a truly integrated 
behavioral, cultural, and biological approach to orchard 
pest management. 

Acknowledpements . We thank the Massachu- 
setts Society for Promoting Agriculture and the Northeast 
Regional Project on Integrated Management of Apple 
Pests (NE-156) for supporting our work on second-stage 
apple IPM. Special thanks go to Leslie White and Esther 
Ruiz who worked on the 1987 studies. Bill Coli, Kathleen 
Leahy, Sue Butkcwich, and Dave Stanley also participated 
in this program. 

Literature Cited 

1. Butkewich.S.L.andR.J.Prokopy. 1985. Update on 
the relative toxicity of orchard pesticides to the predator 
mite, Amblyseius fallacis. Fntit Notes 50(3): 9-11). 



*^f ^fi *il^ *it* 

#n #n rn ^% 



SINGING IN THE RAIN: THE EFFECT OF WEATHER ON 
PLUM CURCULIO SPRING MIGRATION 

Susan L. Butkewich and Ronald J. Prokopy 
Department of Entomology, University of Massachusetts 



The plum curculio (PC), Conotrachelus nenuphar 
(Hebst), is a serious pest of stone and pome fruits east of 
the Rocky Mountains. It is also one of the two most 
important species attacking apples in the Northeast. Less 
is known about the plum curculio than about any other key 
apple pest. Several factors have been responsible for 
Hmiting our success in understanding this insect. PCs are 
cryptically colored and feign death when disturbed, making 
behavioral studies difficult. In their northern range, PCs 
overwinter in leaf litter outside the orchard and return to 
host trees in the spring. The behavioral adaptations 
involved in leaving the orchard in the fall, returning in the 
spring, and locating a host, are complex and not well 
understood. 

From a control standpoint, detection of PC move- 
ment into an orchard in the spring is critical since PCs can 
crawl quickly throughout a host tree, causing significant 
damage to fruit in a short time. To illustrate the rapidity 



with which PC injury may appear, in 1987 unlrcatcd trees 
in Conway, MA had 9% fruit injury on May 21 and 96% on 
May 24! PC populations are difficult to monitor since they 
usually are clumped rather than distributed. Presently, 
control practices are initiated when feeding and cggiaying 
scars on fruit reach economic threshold levels; however, by 
the time fruit damage is detected, considerable fruit injury 
already may have occurred throughout an orchard. More 
effective techniques for monitoring PC appearance on host 
plants in the spring would help us to overcome a major 
stumblingblock in pest control within apple integrated pest 
management programs in the Northeast. 

Many researchers have felt that PC spring migra- 
tion is infiuenced by environmental factors. Quaintance 
and Jenne (3) developed the mean temperature "rule" as 
an index of PC activity, where a mean temperature above 
60°F for 3 or 4 days will result in large migrations. Snap(5) 
agreed with these conclusions. Whitcomb (6) found that 



11 



55° was the minimum temperature for PC activity and that 
75° for 2 or more consecutive days was optimum for 
migration. Furthermore, he suggested that cool weather 
following a warm period may reduce or suspend migration 
until optimum temperatures are reached once again. 
Lathrop (1) believed that other environmental factors 
besides temperature may be important to springmigration. 
Smith and Flessel (4) found that mass migration was 
correlated with humidity as well as temperature. They 
indicated that water loss during periods of low humidity 
may reduce migration. McGiffen and Meyer (2) suggest 
that low temperatures suppress PC activity and aid in the 
conservation of resources until daily air temperature and 
saturation deficits are conducive to flight. They believed 
that temperature must be above the flight threshold, with 
saturation deficit below the desiccation range, for migra- 
tion to occur. 



Because PCs attack border rows first before 
moving toward the block interior, we recommend only a 
border row spray early in the season, with a f uli-biock spray 
at peak PC activity and a border row spray toward ihe end 
of the PC season. Gulhion and imidan have been the most 
effective materials against PC. 

Timing of the first border spray is critical and 
should commence as soon as PC damage is observed on 
fruit, even if rain is predicted, because PC movement to 
host trees is likely to commence as soon as the rain slows 
or stops. The rain may reduce residue longevity, possibly 
making another insecticide application necessary. How- 
ever, delay of a spray may leave you with a heavily damaged 
crop when you awake in the morning! Weigh your choices 
carefully. 



Over the past 4 years, wc have gathered data to 
determine the influence of weather on the spring migratory 
night of PCs from overwintering sites. Ourstudiesindicate 
that PCs are especially likely to move into orchards during 
late day or evening hours under humid, warm conditions 
when the air is relatively calm. Heavy movement occurred 
even during lulls between intermittent rainfall, especially 
when the temperature was above 70°F. 

Based on these findings we want to stress the 
importance of careful daily monitoring of fruit for PC 
feeding and egglaying, especially when weather conditions 
are ideal for migration. Examine 5 or 10 developing fruit 
per tree for fresh feeding or egglaying scars on several trees 
along rows that border woods. Feeding injury appears as 
a small round hole, often undercut so that the hole is larger 
beneath the skin. Oviposition scars are crescent-shaped. 

Our research indicates that during migratory 
night into an orchard, PCs may use visual and olfactory cues 
to locate a host tree. However, it appears that odor alone 
is a stronger stimulus than vision alone. Furthermore, in 
laboratory studies, we found that host odor aids PCs in fruit 
location and actually "turns on" feeding behavior. PCs 
readily locate and feed on sap exuding from cut or wounded 
branches. We therefore wonder if PCs might be attracted 
to recently pruned trees. 



Literature Cited 

1. Lathrop, F. H. 1949. Biology of the plum curcuiio in 
Maine./. Econ. Entomol. 42:12-18. 

2. McGiffen, M.E. and J. R. Meyer. 1986. Effect of 
environmental factors on overwintering phenomena and 
spring migration of the plum curcuiio, Coiiolrachclus 
^^^(^/^/^/•(ColeopterarCurculionidae). Environ. Enloniol. 
15: 884-888. 

3. Quaintance, A. L. and E. L. Jenne. 1912. The plum 
curcuiio. U. S. Dept.Agric. Bur. Entomol. Bull. 103:1-250. 

4. Smith, E. H. and J.K. Flessel. 1968. Hibernal ion of 
the plum curcuiio and its migration to host trees. J. Econ. 
Entomol. 61:193-203. 

5. Snap, O. \. 1930. Life habits of the plum curcuiio in 
the Georgia peach belt. U. S. Dept. Agric. Tech. Bull. 1 88:4- 
76. 

6. Whitcomb, W. D. 1929. The plum curcuiio in apples 
in Massachusetts. Mass. Agric. Exp. Sta. Bull. 49:26-52. 



* a^ ^M ^» ^1^ 

^R ^R ^^ ^J^ 



12 



A COMPARISON OF INSECTICIDAL SOAP AND AMITRAZ 
AS SUMMER SPRAYS AGAINST PEAR PSYLLA 



William M. Coli, Anthony Rossi, and Kathleen Leahy 

Departments of Entomology and Plant & Soil Sciences, University of Massachusetts 



The pear psylla (Psylla pyricola) is well known as 
an important pest of pears, causing damage in the form of 
reduced tree vigor and through the accumulation of excre- 
ment (honeydew) and resultant sooty mold fungus on fruit, 
foliage, and wood. In commercial pear orchards, psylla are 
often difficult to control due to pesticide-induced resis- 
tance to many registered pesticides. We frequently have 
seen excessive psylla injury, giving trees a blackened ap- 
pearance, even in blocks which received a regular spray 
program, and a number of growers have reported increas- 
ing difficulty with psylla control in recent years. 

To some extent, psylla are a problem because 
growers often do not recognize that a particular material 
that had been effective in the past is no longer providing 
control. For example, some growers may .still be able to use 
azinphosmcthyl or phosalone against psylla, but in many 
instances these materials will not adequately control the 
pest. Synthetic pyrethroids generally still are effective, but 
continued use, especially of multiple applications in a 
season, will almost certainly result in the development of 
resistance. For most pear growers, dormant oils will 
suppress psylla in the early part of the season, but fre- 
quently one or more applications of amitraz, a highly toxic 
material, are required during the July through August 
period. 

Because of the potential for psylla to develop 
resistance to amitraz and the negative effects of this and 
other registered pesticides on beneficial arthropods, it is 
imperative that alternative approaches to managing pear 
psylla be developed and tested. For example, researchers 
in Washington achieved limited success by washing honey- 
dew from fruit with water sprays. In this article, we describe 
a trial conducted in 1987 at a small commercial pear 
orchard to determine if insecticidal soaps have any poten- 
tial in commercial psylla control programs by "cleaning" 
fruit, by direct psylla control, or by both. For more informa- 
tion on pear psylla management strategies, see the 1988 
March Message (University of Massachusetts Cooperative 
Extension). 

The trial was conducted in a 1 acre orchard of well- 
pruned, 8-year-old Bartlett pear trees in Belchertown, MA. 
Treatments were laid out in a randomized complete block 
design, using 6 replications of 3-tree plots for each treat- 



ment. Weekly sampling for all psylla life stages (eggs, 
softshcll nymphs, hardshell nymphs, and adults), honey- 
dew, and beneficial arthropods was conducted by observ- 
ing the last four leaves on 10 succulent terminals from 
throughout the canopy of the center tree of each plot. 

Treatments were: (1) untreated check, (2) ami- 
traz @ 2 pints per 100 gal. water, and (3) SaferTM soap @ 
2 gal. per 100 gal. water. All treatments were applied until 
runoff with a motorized hydraulic handgun sprayer at 200 
psi, after 30% of terminals were infested with active psylla 
stages (July 28). Because trees were not cropping heavily, 
at harvest fruit from all trees in each 3-tree plot were 
combined and examined closely for signs of injury. Data 
were analyzed using analysis of variance, and means were 
separated using Duncan's New Multiple Range Test. 

Data in Figure la indicate that both the soap and 
amitraz treatments caused a significant reduction in num- 
bers of all active psylla stages (softshell, hardshell, and 
adult) compared to the check on August 7 and August 12. 
By August 19, the quantity of active psylla stages on treated 
trees did not differ significantly from those on the check; 
however, treatment-related pest reduction allowed fruit to 
be harvested with no further treatment and with no down- 
grading of fruit from honeydew or sooty mold when soap 
or amitraz was used. 

When life-stage data were analyzed separately, 
results indicated that neither treatment caused a significant 
reduction in numbers ofsoftshell nymphs (Figure lb). This 
result may be due to the protection afforded this stage by 
drops of honeydew which they secrete and hide within. 
Softshcll nymphs typically also are protected by their 
tendency to feed in leaf axils where sprays may not ade- 
quately reach. Also, since neither treatment was expected 
to have an effect on eggs, undoubtedly a certain portion 
hatched after the treatment date, resulting in higher 
softshell nymph numbers. This finding suggests that there 
is a need for back-to-back soap applications to prevent 
nymph numbers from continuing to expand, which is 
important because it is nymphal feeding and excrement 
which sap the tree of its fluids and soil the fruit. Hardshell 
nymphs were reduced by both treatments as of the August 
7 sample date (Figure Ic). Although significant differences 
disappeared by subsequent sample dates (as surviving soft 



13 



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Pear Psylla, Soft-Shell Stage 



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Figure 1. Number of active stages of pear psylla on check, Safer soap-, and amitraz-treated Bartlett pear trees. 



shells continued to develop), in practical terms, psylla 
populations under both spray treatments likely were below 
most growers' "visual action threshold" through harvest. 
Nonetheless, in blocks where psylla build up earlier in the 
season, further applications of soap and amitraz likely 
would be required. 

Numbers of psylla adults (Figure Id) also were 
reduced significantly by both soap and amitraz. Because 
adult numbers were significantly higher in amitraz plots on 
July 23 (pre-treatment), it can be argued that amitraz 
performed better than soap against this stage. The residual 
effect of amitraz compared to non-residual soap could 
account for this apparent difference. 

Although check terminals were infested com- 
pletely and showed honcydew and sooty mold growth as 
early as August 7, at harvest only a few fruit from check 
trees showed signs of honeydew. While no evidence of 
spray toxicity to foliage was noted in this trial, 49% of Safer- 
treated fruit were found to be injured at harvest. Phytotox- 
icity consisted of dark-colored surface lesions about 1 cm 
in diameter, apparently formed when soap concentrated at 
the bottom of treated fruit. This injury might be avoided 



by the use of spreading agents to reduce soap accumula- 
tion, by use of a different rate, or by spraying when drying 
conditions arc optimal. 

We compared the cost of applying amitraz and 
Safer soap using a price of $45 per gallon for amitraz and 
$9 per gallon for Safer soap (retail price when purchased 
in volume) and recommended rates. The use of Safer soap 
($54 per acre using a 3(X) gal. dilute base) was 37% more 
costly than amitraz ($34 per acre) under the conditions of 
our test. However, the manufacturer reports that they arc 
working on a second-generation material which is hoped 
will be as effective as the present soap but at 30% to 50% 
of the cost. Moreover, it is difficult to estimate the value of 
reduced pesticide resistance, reduced outbreaks of secon- 
dary pests (e.g., mites), and of reduced negative effects on 
beneficial species that may result from the use of soaps. 
Also unknown at this time is whether or not growers could 
receive a premium price in specialty markets by growing 
"low-spray" or even "organic" pears using dormant oils 
and soap sprays as the basis of a spray program. Positive 
results in these areas could easily affect the economics of 
spray decision-making. 



14 



We conclude that insecticidal soaps may have a 
role in future pear psylla control programs in spite of their 
higher cost; however, more work needs to be done using 
spray additives to reduce or eliminate fruit phytotoxicity. 
Because insecticidal soaps arc non-selective, possible 
negative effects on beneficial species (aphid predators, 
spiders, minute pirate bugs, etc.) must be investigated. 



Further, other than learning that defoamcrs arc essential 
when applying soaps, we know very little at present about 
their application through air-blast sprayers, or whether 
they may be applied using low-volume techniques. Conse- 
quently, we are not prepared at this time to recommend 
insecticidal soap on a large scale, although growers are 
encouraged to experiment in small blocks. 



* * 



* * 



A REPORT ON THE 1987 MASSACHUSETTS APPLE IPM 
PROGRAM 



William M. Coli, Kathleen Leahy, Daniel R. Cooley, Ronald J. Prokopy, and Mary T. O'Brien 
Departments of Entomology and Plant Pathology, University of Massachusetts 



Acknowledgements: We wish to thank Keith 
Bohne, Alex and Charlie Dowse, Tony Lincoln, Frank 
Parker, Jesse and Wayne Rice, Ed Roberts, Bill Rose, 
Mike and Tim Smith, Tony Rossi, and National Park 
Service staff, Ron Catudal and Gene Gabriel, for their 
cooperation. Thanks also to New England Fruit Consult- 
ants, Sue Butkewich, and Tom Green for information they 
provided which we included in pest messages and reports. 
Special thanks to Regional Fruit Agents, Jim Williams and 
DomMarini, for performing weekly scouting ofacommcr- 
cial orchard in their region and reporting their findings for 
use in pest alert messages. Thanks to all Regional Fruit 
Agents for speedy turnaround of pest messages. 



Extension Program Activity 

As in previous years, the apple 1PM program was 
funded by a combination of state, federal, and grower 
sources. Voluntary grower contributions totaled $3,200 in 
1987, a 14% increase from last year. We greatly appreciate 
this continued support, and we consider it further evidence 
that Massachusetts apple growers, through hiring IPM 
consultants and support of Extension programs, have 
adopted IPM on a large scale. 

Program activities were similar to those in 1986, 
and continued to focus on grower and other group educa- 
tion, information-transfer using newsletters, code-a- 
phones, twilight meetings, and orchard visits, and on per- 
forming appropriate adaptive studies. Eight commercial 
orchard blocks, two blocks at the University of Massachu- 
setts Horticultural Research Center (HRC) in Belcher- 



town, and one at an historic orchard in Quincy were 
monitored weekly for arthropods and pathogens affecting 
tree fruits. Increased emphasis was placed on monitoring 
peach and pear pests and including this information in pest 
messages. Scab infested leaves which had been placed in 
wire cages at cooperator sites in November, 1986, were 
collected weekly and examined to determine apple scab 
spore maturity. In addition, temperature and rainfall were 
recorded at the HRC, and other pest information was 
gained by occasional orchard visits, and by reports from 
Sue Butkewich, Tom Green, growers, Extension workers 
in other states, and private scouts and consultants. 

Plant Pathology expanded the Vcnliiria iitacqiialis 
(apple scab) ascospore maturity monitoring to cover more 
effectively the range of development in the stale. As a side 
benefit, it was possible to begin to model the development 
of ascosporcs, and relate it to degree days. In New 
Hampshire, such a model has eliminated the need for 
frequent maturity sampling. However, discrepancies be- 
tween the New Hampshire results and tests in other states 
make it advisable for us to test the model in Massachusetts. 

Cooperating growers were strongly encouraged 
tobuy modified recording hygrothermographs, which were 
made available at a bulk discount along with weather 
shelters or plans for their construction. Weather data from 
these stations, as well as from the HRC, were used to advise 
growers on the intensity of the scab pressure. 

Scouting information was used to reply to grower 
calls and to write twice-weekly Entomology Pest Messages 
from April 7 to August 25. Plant Pathology messages were 



15 



written weekly during the primary scab season, and in 
response to observed problems thereafter. Messages were 
transmitted via the INFONET computerized bulletin 
board system (BBS). The 3 regional fruit agents again 
distributed messages as weekly newsletters and via 24-hour 
code-a-phoncs. Recorded code-a-phone messages contin- 
ued to be used by growers at levels comparable to past 
years. A few growers accessed the INFONET BBS directly 
from their own computers. 

Entomology and Plant Pathology staff members 
made a combined total of approximately 150 orchard site 
visits during the year, assessing pest problems faced by 
large and small commercial orchardists. Staff assisted 
pomologists with apple maturity assessments during har- 
vest using the starch-iodine test, and this information was 
disseminated via INFONET and newsletters. Maturity 
alerts provided an important harvest management tool for 
growers, especially when less daminozide (AlarTM) was 
used. 

Staff members gave a total of 28 talks at grower 
and other group meetings and authored or co-aulhorcd 6 
Fniit Notes articles, 20 journal articles, and 1 proceedings 
article. Entomologyand Plant Pathologystaff also collabo- 
rated with Dr. Rick Weires, Hudson Valley Lab, on the 
annual March Message. 



Table 1. Percent insect- and disease-inj 


urcd fruit in 


8 commercial blocks in 1987, compared to 1978-86. 




Fruit infested (%) | 


Injury type 


1987 




1978-86 


Tarnished plant bug 


1.30 




1.64 


European apple sawfly 


0.20 




0.36 


Plum curculio 


0.71 




0.54 


Apple maggot fly 


0.89 




0.06 


San Jose scale 


0.01 




0.67 


Leafrollers 


0.08 




0.03 


Green fruitworm 


0.02 




0.07 


Codling moth 


0.00 




0.01 


Other insects* 


0.00 




0.01 


Apple scab 


0.32 




0.83 


Calyx end rot 


0.28 




0.20 


Black rot 


0.03 




0.14 


Fly speck 


0.72 




0.05 


Other diseases** 


0.07 




0.12 


*Othcr insects include: 


white 


apple 


Icafhopper, 


aphid honeydew and sooty mold 






**Other diseases include; 


sooty blotch, moldy core, | 


white rot, and quince rust 









In 1987 we completed year 2 of a cooperative 
agreement with the U.S.Dept. of the Interior, National 
Park Service, which seeks to implement IPM in historic 
orchards at the Adams National Historic Site (NHS), 
Quincy, MA, at the Roosevelt/Vanderbilt NHS, Hyde 
Park, NY, and at the Morristown NHS, Morristown, NJ. 
Under our direction, park staff pruned trees, monitored 
insects, recorded temperature and leaf wetness, and ap- 
plied pesticides based on scouting. The Adams Historic 
orchard shows the most completely developed pest man- 
agement plan, and produced a crop of good quality apples 
this season for the first time in recent history. 

A Training Workshop held at the University of 
Massachusetts February 24-26, 1987, as part of the USDI- 
-NPS cooperative agreement was attended by 22 National 
Park Service staff from throughout the U.S., and provided 
training in concepts and techniques of 1PM for historic 
orchards, including lectures by several University faculty 
and staff. Participants identified 26 historic fruil plantings 
in the NPS system, the earliest site dating from 1752. 
Evaluations indicated highly positive response to work- 
shop structure and content. 



Insect and Mite Status, 1987 

Tarnished plant bug (TPB) was again the single 
most important cause of fruit injury noted at harvest in 
Massachusetts orchards (Table 1), and TPB remains a 
difficult pest to manage. The goal of predicting the optimal 
liming of TPB sprays still eludes us. However, we rarely 
observe severe fruit distortion from TPB feeding in com- 
mercial orchards. Thus, much of the injury we see has 
comparatively little effect on grade. 

European apple sawfiv (EAS) activity was very 
high in 1987 throughout Massachusetts and in other parts 
of the Northeast. Activity began shortly before bloom (5/ 
14 to 5/21) in most areas, although a few EAS were caught 
on white plant bug traps a week before bloom. Record 
captures of EAS were noted, especially in a Wilbraham 
block wherein cumulative average captures exceeded 39 
per trap by 5/14. The highest single trap capture was 89 
EAS, a new "record" for us, although Lorraine Los at the 
University of Connecticut has us beat, with her report of up 
to 100 EAS per trap! Numerous EAS-scarred or -infested 
fruit were seen in orchards in June, but most fell from the 
tree, and harvest surveys showed only an average amount 
of EAS fruit injury (Table 1). 

A pple maggot fiv (AMF) was first reported on 7/ 
6 on a red sphere in Westborogh, and activity was early and 



16 



high. In some parts of the state, fly emergence and activity 
followed normal patterns, but in others, where rain show- 
ers were infrequent, AMF activity in August was below 
normal. In one warmer block of Delicious peak nonbaited- 
spherc capture (mean of 4.5 per trap) occurred during the 
week ending 9/11. AMF fruit injury in 8 monitored blocks 
averaged 0.89% (Table 1), and in an additional 18 grower- 
sprayed blocks injury averaged 1.4%, unusually high levels 
for sprayed commercial blocks. Overall, AMF trap cap- 
tures were high, with an average of 25 flies per trap in the 
18 aforementioned blocks from early July to early Septem- 
ber. 

European red mite activity also began early, with 
up to 20 mites per leaf seen on 5/14 in a Granville block 
which had received an oil treatment and which did not have 
a history of using predator-harsh materials. Two moni- 
tored blocks needed treatment for mites before the end of 
May. Pcrhapsdue to early prey mite buildup, predator mite 
activity was also very high later in the season. A.fallacis and 
the Stigmaeid mite, Z. mali (yellow mites), were common 
in some monitored blocks. Some orchards had as many as 
20% of leaves with ^./a//ac/.y, and up to 40% with Z. mali 
in August. In addition, some unusual predators, such as the 
Conioptcrix, were noted in Granville on 7/ 14; however, the 
Coccinelliid beetle, Stclhoris puncliim, an important mite 
predator in Pennsylvania and parts of New York, was not 
reported anywhere in Massachusetts this season. 

Plumcurculio pressure began shortly after bloom 
and continued for 3 to 4 weeks. Most growers maintained 
an insecticide cover through the period, and PC damage 
was not significant in monitored blocks. 

Leafminers (LM^ showed unusually low activity 
throughout the state. Overwintering generation LM emer- 
gence was apparently affected by very cold weather and 
snow during the time of emergence. Adults which had 
begun to move from the groundcover to tree canopies may 
have been "knocked down" by the cold. After that, visual 
trap captures continued at a low level into bloom. The few 
growers who had a leafminer problem had difficulty timing 
sprays correctly, and few monitored blocks had 100% 
leafminer control. Third generation LM injury (late sea- 
son) was high in several blocks, which should also have 
resulted in an increase in parasitism, normally highest in 
that generation. 

Potato leafhopp cr (PLH) was first spotted in a 
commercial orchard in Wilbraham on July 8, and activity 
continued in some parts of the state through August. By 
harvest, "hopper burn", a yellowing of leaf margins, some- 
times progressing to death of leaf margins, was widespread 
in the state. A single azinphosmethyl spray appeared to 



provide control at the HRC, and we have had no reports of 
apparent PLH resistance to other organophosphates. 

A pple grain aphids and green apple aphids both 
reached high numbers before bloom in many instances. 
Green aphids dispersed onto apple fruit early as well, 
although absolute numbers of aphids on fruit remained 
low. In monitored orchards, however, no significant honey- 
dewand no sooty mold problems were noted during harvest 
surveys in spite of aphid presence earlier. Cecidomyiid 
predator larvae were present in overwhelming numbers (5 
to 10 per terminal). Syrphid larvae were not really a factor 
in biocontrol until near the end of aphid activity. 

Japanese beetles were noted in unusually high 
numbers in some commercial orchards in 1987. Although 
one grower reported high enough defoliation to warrant 
treatment, most problems were not that severe. Beetle 
problems were typically localized and could have been 
spot-treated. 

Birds caused a significant amount of damage to 
fruit this year. Cortlands continued to be a favorite target 
of crows, bluejays and other species. Peaches also received 
much damage statewide. It has been suggested that the dry 
summer forced birds to look for moisture sources wherever 
they could, and that recurrence may be reduced in similar 
years by providing bird baths or other clean water sources. 



Disease Status, 1987 

Scab i ncidence wasgenerally light, but variable. In 
the eastern part of the state, within 50 miles of the coast, 
scab was heaviest. Early season rain in the eastern part of 
the state lasted for longer periods, though temperatures in 
both east and west were similar. Infection periods, there- 
fore, occurred in the east when they did not in the western 
areas. A dry summer meant that there was little, if any, 
secondary spread after June. Fruit scab was generally 
confined to the calyx end, indicating early season infections 
which spread. 

Blossom end rot w as heavier than normal in some 
orchards. The same weather which promoted calyx-end 
scab undoubtedly promoted end rot. The causative organ- 
ism for this was not Sclerolinia but Allcmaria. 

Powdery mildew developed into a more serious 
problem than usual last year. We used the pest messages to 
advise growers that the disease was becoming widespread, 
and that fungicides which affect both mildew and scab 
should be used. 



17 



Related Research and Adaptive Studies 

An important part of 1987 activity involved cm- 
barking on the second stage of apple IPM in a large number 
of commercial orchards. Second-stage IPM projects focus- 
ing on apple maggot fly (the key insect pest after May) and 
key Icpidopteran pests and on phytophagous mites and 
apple scab were initiated with funding from outside grants. 
As part of the mite biocontrol project, groundcover surveys 
of 36 second-stage blocks were undertaken. Results of 
these surveys will enable us to establish orchard classifica- 
tions (mowing vs. herbicide, hard vs. soft spray program, 
and broadleaf vs. grass groundcover) prior to the start of 
1988 mite sampling. We wish to acknowledge the signifi- 
cant contribution of James Williams and Karen Hauschild 
who assisted with these surveys, and Dr. Prasanta 
Bhowmik, who provided training and assistance in orchard 
weed identification. We will report more fully on all 
second-stage IPM projects in other Fniil Notes articles. 

Fungicide, insecticide, and insect growth regula- 
tor trials again were performed at the HRC and at grower 
sites in 1987. This activity involved testing chem icals which 
may be or presently arc a component of commercial spray 
programs. Evaluation of pesticide effects on mite preda- 
tors continued, as did the evaluation of disease-resistant 
apple cultivars. Monitoring continued in a commercial test 
block of disease-resistant cultivars established at the Rice 
farm in Wilbraham. This planting is intended to determine 
the feasibility of using no fungicides and a minimum of 
insecticides in a commercial setting. 

A set of 5 ergosterol biosynthesis-inhibiting 
chemicals (Si's) was tested at 10-day application intervals, 
following delayed application (tight cluster was the first 
application). This study was designed to test the feasibility 
of increasing intervals and delaying the first fungicide 
application using Si's. This work will be described in other 
Fmil Notes articles. 

IPM blocks at the HRC were treated with a 
registered SI (RubiganTM) on a delayed application basis 
under Plant Pathology supervision. Effective control was 
obtained with 2 fewer fungicide applications than in previ- 
ous seasons. Another experimental material (not an SI), 
with potential for long-term residual fungicidal activity 
combined with low environmental hazard, was tested. Two 
applications of the material, made in early and late June, 
effectively stopped scab development. Next season, the 
material will be tested in a series to determine whether it 
might offer a means for drastically reducing summer cover 
sprays and possibly primary season sprays as well. 

Two root fungicides and various planting hole 



amendments were tested for effect on early tree growth. 
This experiment is a continuation from 1986 and indicates 
that a 50% peat amendment and one of the fungicide 
treatments (AlietteTM) are the two most effective tech- 
niques for promoting the growth of newly planted trees. A 
further report will appear in a future Fruit Notes article. 

Daniel Cooley began work on a regional IPM 
project with Dr. William MacHardy (NH) and Dr. David 
Roscnberger (NY), to determine if the scab inoculum dose 
from the previous season will predict the length to which 
the first application of fungicide can be delayed the follow- 
ing season. One Massachusetts orchard was involved in 
this study, and plans were to expand the project to second 
stage IPM blocks last fall. 

Cooley also developed a prototype expert .systems 
(computerized decision support software) for apple scab 
and apple root problems in conjunction with Dr. Paul 
Cohen of the Computer and Information Science Depart- 
ment, using Public Service Grant funding. We have been 
exploring ways to integrate this technology into the overall 
IPM program. 

Disease-resistant apple cultivar evaluation con- 
tinued, with emphasis on horticultural factors, such as 
maturity and storability. Plans were made and funding 
obtained for a major disease resistant block at the HRC. 
Observation of an immature block planted in Wilbraham 
continued, and bud wood was distributed to a commercial 
grower, suggesting that such a program might promote 
disease-resistant cultivars. 

Related entomology research and adaptive stud- 
ies in Prokopy's lab continued to focus on improvement of 
monitoring traps for apple Icafminers and on the host- 
finding behavior of the apple maggot fiy and the plum 
curculio. Other related entomology studies involved a test 
of insecticidal soap against pear psylla (Psylla pyricola), the 
most important pear pest in most orchards. In cooperation 
with Dr. Alan Eaton, University of New Hampshire, we 
continued tosurvey the distribution, in New England, of the 
European apple sucker, Psylla mail, potentially a serious 
pest in commercial blocks in the future. Although not yet 
found as a pest in commercial orchards, P. mali appears to 
be present in abandoned orchards throughout the central 
and western counties in Massachusetts, west into New 
York's Hudson Valley and south into Connecticut. 



Plans for 1988 

We propose to continue most of the 1987 activi- 
ties, including: monitoring weather, pathogens, arthro- 



18 



pods, and tree development in at least 8 commercial blocks; 
writing twice-weekly pest messages; presenting 4 grower 
training sessions in each of three regions; performing 
adaptive studies and pesticide trials; authoring extension 
and other publications; and obtaining outside funding. 

Both second-stage projects will continue in 1988. 
The apple maggot-lepidopteran pest project, aimed at 
preventing immigration of these apple pests into an or- 
chard, will utilize most of the same 18 orchards as in 1987. 
The orchard understory work will begin its first full field 
season, with extensive sampling of miles and mite preda- 
tors in about 30 commercial orchards with different 
groundcover characteristics and management regimes. 
Beginning in mid-May, mite sampling in the tree and in the 
row or aisle groundcover will commence. Sampling will 
consist both of visual scans and sample collection at 10 
locations within the block and at block borders. Patholo- 
gists will measure leaf litter decomposition relative to 
groundcover type, and isolate fungi and bacteria to deter- 
mine their effectiveness in decomposing fallen apple 
leaves. A complete description of this project will be 
forthcoming. 

Spore maturity and weather data will be obtained 
on the same scale as in 1987, and Pathology staff will 
continue to evaluate disease-resistant apples including a 
new block to be planted at the HRC. We also will look at 
the possibility of early season fungicide reduction in a 
program which requires early-season estimation of scab 
inoculum dose, and late-season estimation of infection. 



This program could eliminate all fungicides up to tight 
cluster or pink, and fits well into a second-stage IPM 
program. 

Work on expert system development will con- 
tinue, hopefully in conjunction with others in the northeast 
region. Expert systems arc highly relevant to the future of 
IPM, since applications of this technology are a natural 
outgrowth of the apple IPM program, and have the poten- 
tial to make it even more effective. We plan to pursue 
regional and University funding and cooperation in the 
dcvelopmentofacomprehensiveapplelPM expert system, 
which, when released, should be a valuable educational as 
well as managerial tool. 

Continued field tests of insecticidal soap against 
psylla, aphids, and mites arc planned, contingent on fund- 
ing from outside sources. An additional activity planned for 
1988 is an update of previously-established economic 
thresholds, taking into account price changes for fresh fruit 
and pesticides and new data on pest severity. 

This year will be the first of a new cooperative 
agreement with the National Park Service, which will 
involve a survey and inventory of historic orchards and fruit 
tree plantings in the NPS system throughout the U.S. 
Inasmuch as some NPS sites may contain examples of 
historic fruit cultivars which are not available elsewhere, 
this work is being carried out under a directive from the 
Secretary of the Interior to conserve unique genetic re- 
sources (in the form of apple cultivars). 



* 



* * * 



19 



COOPERATIVE EXTENSION 

U. S. DEPARTMENT OF AGRICULTURE 

UNIVERSITY OF MASSACHUSETTS 

AMHERST, MASSACHUSETTS 01003 0099 



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PERMIT No GPRS 



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3 



Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

University of Massachusetts Cooperative Extension, 

United States Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R. Autio and William J. Bramlage 



ISSN 0427-6906 



BIOLOGICAL 



JUL 15 1988 




Volume 53, Number 3 
SUMMER ISSUE, 1988 

Table of Contents 

The Economic Benefits of Summer Pruning 

Effects of Rootstock and Interstock on the 

Growth, Productivity, and Anchorage of a 

Spur and Standard Strain of DeUcious 

Prospects for Greater Use of Biological Control 
Agents Against Pests of Apple in Massachusetts 

Peach Brown Rot Fungicide Trial, 1987 

Mauget Microinjection for Peach X-Disease Therapy 

t 

Reevaluation of NAA as a Preharvest 
Drop Controlling Chemical for Mcintosh 

Postharvest Apple Rots: Dr. Rosenberger's Approach 

Electric Lift Trucks in Refrigerated Facilities 

Potential for Explosions in CA Storage Facilities 

An "Expert System" for CA Storage of Mcintosh 



Fruit Notes 

Publication Information: 

Fruit Notes (ISSN 0427-6906) is published the first day of January, 
April, July, and October by the Department of Plant & Soil Sciences, 
University of Massachusetts. 



The costs of subscriptions to Fndt Notes are $4.00 for United States 
addresses and $6.00 for foreign addresses. Each one-year subscrip- 
tion begins January 1 and ends December 31. Some back issues are 
available for $1.00 (United States addresses) and $1.50 (foreign 
addresses). Payments must be in United States currency and should 
be made to the University of Massachusetts. 



Correspondence should be sent to: 

Fruit Notes 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

University of Massachusetts 

Amherst, MA 01003 



COOPERATIVE EXTENSION POLICY: 

All chemical uses suggested in this publication are contingent upon continued registration. These 
chemicals should be used in accordance with federal and state laws and regulations. Growers are urged 
to be familiar with all current state regulations. Where trade names are used for identification, no 
company endorsement or product discrimination is intended. The University of Massachusetts makes 
nowarrantyorguaranteeof any kind, expressed or implied, concerning the use of these products. USER 
ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY DAMAGE. 



Issued by the University of Massachusetts Cooperative Extension, E. B. MacDougall, Director, in furtherance 
of the acts of May 8 and June 30, 1 914. The University of Massachusetts Cooperative Extension offers equal 
opportunity in programs and employment. 



tJ 



The Economic Benefits of Summer Pruning 



Daniel A. Lass and Martha A. Kimball 

Department of Agricultural & Resource Economics, University of Massachusetts 

Wesley R. Autio, Duane W. Greene, and Richard Clark 
Department of Plant & Soil Sciences, University of Massachusetts 



In previous Fm/fNoto articles [52(3) :7-8 and 53(2): 1] 
Greene and Autio outlined some of the procedures and 
benefits of summer pruning of Mcintosh trees. These 
benefits included earlier coloring (allowing earlier harvest 
and lower losses to drop) and a higher percentage of the 
fruit making the U. S. Extra Fancy grade. In this article we 
shall detail the economic benefits of summer pruning, to 
give growers the necessary information to decide whether 
or not to summer prune. 

In 1986 and 1987 summer pruning studies were per- 
formed on 25-year-old Rogers Mclntosh/M.7 trees at the 
Horticultural Research Center, Belchertown, MA. These 
trees can be considered the standard for the industry. Two 
harvests were made each year. Data were collected on the 
number of bushels harvested in each picking, the number 
which were lost to drop, and the percent of a random 
sample made at the first picking which were U. S. Extra 
Fancy. Additionally, the fruit were observed after storage 



and downgrading due to bruising and softening was esti- 
mated. Most of these data are reported in the previous 2 
articles. 

A distribution of the packout was approximated from 
various observations for the entire yield of trees which were 
summer pruned and those which were not (Table 1). 
Grades were divided into 3 groups: Extra Fancy/Fancy, 
No. 1/Utility, and Processing. Drops were counted sepa- 
rately and assumed to be usable for processing. The per- 
bushel fruit values used in this study were $10.50 for the 
Extra Fancy/Fancy, $6.00 for the No. 1/Utility, and $2.00 
for the processing. One half bushel per tree was assumed 
to be lost during the summer pruning activity. Pruning 
labor was assumed to cost $6.00 per hour. 

Summer pruning reduced the losses to drop and 
downgrading due to bruising and softening, because it 
allowed an earlier harvest of a larger percentage of the 
crop. Summer pruning also resulted in more fruit making 



Table 1. Comparison of returns and costs for summer pruned and control Mcintosh trees. 1 




Not summer 
(bu/acre) 


pruned 
($/acre) 


Summer 


pruned 


(bu/acre) 


($/acre) 


A. Crop yields and values: 










Harvested 


755 




802 




Extra Fancy/Fancy 
No. 1/Utility 
Processing 


581 

113 

61 


$6101 
678 
122 


683 
63 
56 


$7172 
378 
112 


Drop 
Totals 


444 


888 


360 


720 


1199 


$7789 


1162 


$8382 


B. Labor costs: 










Summer pruning (hours) 
Dormant pruning (hours) 

Totals 



21 


$ 
126 


17 
13 


$102 
78 


21 


$126 


30 


$180 


C. Net value 




$7663 




$8202 


1 



Table 2. Comparison of returns and costs for Alar-treated and 


summer pruned trees. 


1 




Alar-treated, 


Not Alar-treated, 


Alar-treated, | 




not summer pruned 


summer pruned 


summer 


pruned 


(bu/acre) 


($/acre) 


(bu/acre) 


($/acre) 


(bu/acre) 


($/acre) 


A. Crop yields and values: 












Harvested 


1019 




802 




1023 




Extra Fancy/Fancy 


815 


$8558 


683 


$7172 


871 


$9146 


No. 1/Utility 


153 


918 


63 


378 


80 


480 


Processing 


51 


102 


56 


112 


72 


144 


Drop 
Totals 


180 


360 


360 


720 


139 


278 


1199 


$9938 


1162 


$8382 


1162 


$10048 


B. Labor costs: 














Summer pruning (hours) 





$ 


17 


$102 


17 


$102 


Dormant pruning (hours) 
Totals 


21 


126 


13 


78 


13 


78 


21 


$126 


30 


$180 


30 


$180 


C. Alar application 




$70 




$0 




$70 


D. Net value 




$9742 




$8202 




$9798 


1 



the higher grades on color because of the increase in light 
penetration into the tree. Summer pruned trees had 
slightly lower yields, but the overall fruit value was $8382 
per acre compared to $7789 for trees that were not summer 
pruned (Table 1). Seventeen hours of labor per acre were 
added by summer pruning, but dormant pruning was 
reduced by 8 hours per acre. Total labor costs were 
increased by only $54 per acre. Summer pruning resulted 
in an additional net value of $539 per acre; a value which 
makes the activity very much worthwhile. 

In these 2 years of study only trees which did not 
receive Alar^^ were used, but we have made estimates 
comparing Alar-treated trees with summer pruned trees 
which did or did not receive Alar (Table 2). Note that these 
estimates were approximations based on our experience 
with Alar and summer pruning. The expected net returns 
were approximately $1540 higher if Alar were used com- 
pared to when summer pruning was practiced without Alar, 
primarily because of the much lower percentage of fruit 



lost to premature drop. Obviously, summer pruning can- 
not compensate completely for not using Alar, but it does 
reduce the losses by approximately one third. Table 2 also 
shows an estimate of the costs and returns of Alar-treated 
trees which were summer pruned, giving a comparable net 
value to Alar-treated trees which were not summer pruned. 
These results suggest that it likely would not be beneficial 
to summer prune if you have already treated with Alar, 
primarily because Alar would keep fruit on the tree long 
enough for red color to develop and the fruit to be har- 
vested. However, summer pruning still may be beneficial 
since earlier coloring would allow earlier harvest, poten- 
tially resulting in higher quality fruit for long-term storage. 

Summer pruning can be a very beneficial procedure 
which causes a small increase in pruning costs, but a 
substantially greater crop value in cases where Alar is not 
used. Growers should consider summer pruning all Mcin- 
tosh trees which will not receive Alar. The economic 
returns speak for themselves. 



* »f» %£^ «X« mSfi 
w^ ^fm a^ *{* 



Effects of Rootstock and Interstock on the Growth, 
Productivity, and Anchorage of a Spur and Standard 
Strain of Delicious 



Wesley R. Autio and Franklin W. Southwick 

Department of Plant & Soil Sciences, University of Massachusetts 



A number of studies have compared spur and standard 
apple strains but commonly have not assessed the addi- 
tional effects of rootstock and interstock. In this study we 
compared the effects of M.7A, M.26, M.9/MM.111, M.9/ 
MM. 106, and MM.lll on the growth, productivity, and 
anchorage of Starkrimson Delicious (spur strain) and 
Gardiner Delicious (standard strain) trees. 

Trees were planted in the spring of 1981 at the Horti- 
cultural Research Center, Belchertown, MA. The experi- 
mental design was a randomized complete block with 7 
replications. Within each block 4 trees were planted per 
strain-rootstock-interstock combination, and the two 
middle trees were used for data collection. All rows were 
20 ft apart, but spacing within rows varied with the combi- 
nation. Starkrimson trees on M.26, M.9/MM.106, and 
M.9/MM.111 were spaced 12 ft apart, and Starkrimson 
trees on M.7A and MM.lll and Gardiner trees on M.26, 
M.9/MM.106, and M.9/MM.111 were spaced 14 ft apart. 
Gardiner trees on M.7A and MM.lll were spaced 16 ft 
apart. 

In 1983 bloom was assessed, and in 1984 bloom, fruit 
set, and yield were measured. In 1985 tree height, spread, 
trunk circumference, and yield were measured. The 1985 
tree spread values were used to calculate theoretical tree 



spacings and theoretical numbers of trees per acre. It was 
assumed that the optimal distance between trees within a 
row should be 50% greater than the 1985 tree spread and 
the distance between rows should be 8 ft greater than the 
distance between trees within a row. The value of 50% was 
used because it resulted in approximately the accepted 
densities for the 2 strains on M.7A, the most tested root- 
stock in the study. These values were used to calculate the 
theoretical yield per acre in 1984 and 1985. 

In September, 1985 these trees experienced the effects 
of Hurricane Gloria, which allowed an assessment of tree 
anchorage of these strains on the various combinations. 
The angle of lean from the vertical was used to measure 
anchorage, since poorly anchored trees were partially or 
completely blown over. 

Tree Size 

Tree height, spread, and trunk circumference, ob- 
tained in November, 1985, are presented in Table 1. For 
each measurement Gardiner trees were significantly larger 
than Starkrimson trees. This relationship between a spur 
and a standard strain has been shown many times. Signifi- 
cant differences also existed among rootstocks within each 



Table 1. Height, spread, trunk circumference, and calculated number of trees per acre in 1985 of 
Gardiner and Starkrimson Delicious trees planted In 1981. 


Height (ft) 


Spread (ft) 


Trunk 
circum. (cm) 


Trees 1 
per acre 1 


Stock Gard. 


Stark. 


Gard. 


Stark. 


Gard. 


Stark. 


Gard. 


Stark. 1 


M.7A 13.7 b^ 
M.26 11.4 d 
M.9/MM.111 12.2 c 
M.9/MM.106 12.6 c 
MM.lll 14.9 a 

Average 13.0 **'' 


12.3 a 
10.1b 
10.0 b 
10.8 b 
12.3 a 

11.1 


10.7 a 

9.2 b 

9.0 b 

10.5 a 

10.3 a 

9.9 


7.9 a 
6.4 b 
6.2 b 

7.8 a 
8.4 a 

** 7.4 


26.6 a 

19.2 d 

21.3 c 

23.4 b 
26.9 a 

23.5 ** 


23.8 a 
18.1 be 

16.9 d 
19.5 b 

23.7 a 

20.4 


119 b 191 b 
153 a 276 a 
160 a 291 a 
121 b 198 b 
126 b 175 b 

136 ** 226 


'Means within columns not followed by the same letter are significantly different at odds of 19:1. 1 
''Gardiner and Starkrimson are different at odds of 99 to 1. 1 



Table 2. Flowering and fruit set of Gardiner Delicious and Starkrimson Delicious trees planted in 


1981. 






Number of blossom cluster 






















Fruit set 
















1983 


1984 






1984 




Stock 


(/cm 


trunk circ.) 


(/cm limb 


circ.) 


(/cm limb ( 


:irc.) 


Gard. 


Stark. 


Gard. 


Stark. 


Gard. 




Stark. 


M.7A 


8.3 c' 


9.9 c 


4.0 b 


3.5 b 


16.8 ab 




23.4 ab 


M.26 


11.8 b 


10.6 b 


5.6 a 


4.3 a 


16.6 be 




11.8 be 


M.9/MM.111 


10.2 be 


9.2 be 


4.9 a 


4.5 a 


11.6 c 




10.4 c 


M.9/MM.106 


13.6 a 


12.4 a 


5.3 a 


4.0 a 


22.6 a 




25.5 a 


MM.lll 


2.0 d 


0.8 d 


4.0 b 


2.9 b 


9.6 c 




13.4 c 


Average 


9.2 


ns" 8.6 


4.8 ** 


3.9 


15.4 


ns 


16.9 


'Means within columns not followed by the same letter are significantly different at odds of 19 to 1. 




''If **, thenGardinei 


■ and Starkrimson arc different at 


odds of 99 to 1 


. Ifns, 


then Gardiner 


md Starkrimson | 


are not significantly 


different. 















Table 3. Yield per tree 


and theoretical yield per : 


acre for Gardiner and Starkrimson Delicious 


trees 


planted 


in 1981. 




















■ 


Stock 






1984 




1985 




Cumulative 1 


Gard. 




Stark. 


Gard. 


Stark. 


Gard. 




Stark. 


A. Yield per tree 


(bu) 


















M.7A 




0.4 b^ 




0.3 b 


0.6 be 


1.3 be 


1.0 be 




1.6 be 


M.26 




0.4 b 




0.3 b 


0.9 a 


1.5 b 


1.3 b 




1.8 b 


M.9/MM.111 




0.1 c 




0.1 c 


0.9 ab 


1.0 cd 


1.0 c 




1.1 c 


M.9/MM.106 




0.7 a 




0.5 a 


1.0 a 


1.9 a 


1.7 a 




2.4 a 


MM.lll 




0.1 c 




0.1 c 


0.4 c 


0.8 d 


0.5 d 




0.9 d 


Average 




0.3 


ns'' 


0.2 


0.8 


1.3 


1.1 


** 


1.6 


B. Yield per acre 


(bu) 


















M.7A 




47 b 




57 b 


63 ab 


250 b 


109 ab 




307 b 


M.26 




49 b 




58 b 


138 a 


385 a 


187 a 




444 a 


M.9/MM.111 




20 c 




24 c 


144 a 


312 ab 


165 a 




336 b 


M.9/MM.106 




79 a 




94 a 


123 ab 


371 a 


202 a 




466 a 


MM.lll 




15 c 




12 c 


42 b 


136 c 


57 b 




147 c 


Average 




42 


ns 


49 


102 ** 


290 


144 


** 


340 


^Means within columns not followed by 


the same 


letter are significantly different at odds of 19 to 1. 




1f**,thenGardi 


ner and Starkrimson are different at odds of 99 to 1. 


If ns, then Gardiner and Starkrimson | 


are not significantly different. 

















strain. Gardiner trees were tallest on MM. Ill, followed by 
those on M.7A. The two interstem combinations were 
similar in size, and trees on M.26 were the shortest. 
Siarkrimson trees were tallest on MM. Ill and M.7A, and 
the M.26, M.9/MM.111, and M.9/MM.106 trees were of 
similar height. Tree spread was greatest for trees on 
MM.lll and M.7A. 

As expected, the size of the spur trees allowed for 
significantly more trees per acre than for the standard 
strain (Table 1). For both strains the M.26 and M.9/ 
MM.lll rootstocks resulted in the smallest trees and most 
trees per acre. The M.7A, M.9/MM.106, and MM.lll 
trees were of similar tree spread which resulted in similar 
values for trees per acre. Differences in precocity may 
cause inaccuracies in determining theoretical densities 
using these young trees. For instance, the trees on M.9/ 
MM. 106 had the highest yields for 1984 and 1985, and as a 
result their growth rate may have been slower than trees on 
M.7A. When a similar formula is used to calculate ultimate 
spread for trees on M.7A and M.9/MM.106, it would be 
expected that either the density for M.9/MM.106 would be 
underestimated or that for M.7A would be overestimated. 
In this case it appears that the theoretical density for trees 
on M.9/MM.106 maybe lower than the ideal density. The 
situation may be the reverse for trees on MM.lll, where 
the theoretical density was substantially higher than com- 
monly recommended. 

Flowering and Fruit Set 

Table 2 shows the flowering and fruit set data for 1983 
and 1984. No significant differences existed between 
Gardiner and Starkrimson as to the quantity of bloom in 
1983, but in 1984 Gardiner had significantly more bloom 
than Starkrimson. These trees were in their fourth leaf in 
1984 and the greater bloom on Gardiner, the standard 
strain, may have been due simply to variation in these trees 
which were just coming into production. In general the 
interstem trees and trees on M.26 had more blossom 
clusters than did trees on M.7A or MM.lll. 

Fruit set in 1984 (Table 2) was similar for the 2 strains, 
but trees on M.9/MM.106 had the highest set and those on 
MM.lll and M.9/MM.111 had the lowest. 

Yield 

Yield per tree and theoretical yield per acre are 
presented in Table 3. On a per-tree basis the cumulative 
yield for 1984 and 1985 was significantly higher for the 
Starkrimson than the Gardiner trees. Some studies have 
shown a similar relationship, with the spur strain yielding 
more than the standard strain; however, most studies have 
shown the reverse. Cases such as this one, where the spur 
yielded more than the standard strain, may reflect precoc- 
ity rather than ultimate yield potential. As the standard 



trees become Wger it would be expected that they would 
yield more than the spur trees. 

Theoretical production per acre was significantly 
higher for Starkrimson. Since the spur strain was smaller 
and more productive it had a much higher theoretical yield 
per acre. 

Yields per tree for the various rootstocks showed that 
trees on M.9/MM.106 produced the most fruit, whereas 
those on MM.lll produced the fewest. The MM.lll root, 
with or without an M.9 interstock, appeared to confer a low 
yield potential to the tree, or at least resulted in less 
precocity. There also was a lower fruit set for trees with 
these roots. It is particularly interesting to note the 
difference between the two interstem trees. Trees on M.9/ 
MM. 106 had the highest theoretical yield per acre, fol- 
lowed by those on M.26, M.9/MM.111, M.7A, and 
MM.lll. These data suggest that the interstem trees and 
those on M.26 can result in the highest productivity. 



Table 4. Tree lean after Hurricane Gloria, | 


1985. 








Lean from vertical (°) 1 


Stock 


Gard. 


Stark. 


M.7A 


53 d' 


33 c 


M.26 


20 b 


19 b 


M.9/MM.111 


16 b 


20 b 


M.9/MM.106 


34 c 


19 b 


MM.lll 


a 


a 


Average 


25 


ns" 18 


'Means within columns not followed by the 1 


same letter are significantly different at | 


odds of 19 to 1. 






>'Gardiner and Starkrimson are 


not signifi- 


cantly different. 







Anchorage 

Information already presented suggests that MM.lll 
is a poor rootstock for Delicious, because first of all, it 
produces the largest tree, and secondly, it has the lowest 
yield per tree and theoretical yield per acre. However, it is 
commonly thought to be well anchored. We were able to 
measure anchorage easily in 1985 because of the effects of 
Hurricane Gloria. Trees were subjected to winds in excess 
of 65 miles per hour, and substantial tree movement 
resulted. After the hurricane, several trees were leaning, 
and the angle from vertical was measured (Table 4). The 
poorest anchorage was seen with trees on M.7A roots, 
where the average angle oflean was 43°. Treeson MM.lll 



showed no signs of leaning and were by far the best 
anchored. Granted, the lower fruit load on MM.lll trees 
may have reduced somewhat the tendency to lean, but they 
also h-^d the largest leaf surface and above-ground por- 
tions, providing a larger area for wind action and more 
potential for damage. 



Trees on MM.lll were undesirable in terms of size 
and yield but were much better anchored than any other 
rootstock or rootstock-interstock combination. Under 
certain conditions the better anchorage would make trees 
on MM.lll much more desirable than other combinations. 



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Prospects for Greater Use of Biological Control Agents 
Against Pests of Apple in IVIassachusetts 



Roy G. Van Driesche 

Department of Entomology, University of Massachusetts 



A recent publication of the Massachusetts Agricul- 
tural Experiment Station, Opportunities for Increased Use 
ofBiological Control in Massachusetts by Van Driesche and 
Carey (Bulletin 718), has reviewed the status of the use of 
parasites and predators for insect and mite pest control for 
all major crops in Massachusetts. This report is available 
through the Bulletin Distribution Center, Cottage A, at the 
University of Massachusetts at Amherst for $7.00. For 
apples, several possibilities exist to expand the degree of 
pest control provided by predators and parasites. 

Little to no possibility exists for control of the major 
apple pests (apple maggot fly, plum curculio, and the 
tarnished plant bug). These species have few exposed life 
stages suitable for attack by beneficial insects, and because 
they are direct pests of the fruit, little tolerance exists for 
their presence in commercial orchards. Certainly a few 
parasites of these species do exist, but they offer no 
reasonable hope for commercially acceptable levels of 
control. The controls applied for these species do, how- 
ever, play a key role in regard to the biological control of 
those species for which effective biological control agents 
do exist - namely aphids, scales, white apple leafhopper, 
mites, and leafminers. All of these groups can come under 
effective control by predators or parasites given favorable 
orchard management. 

The traditional use of continuous insecticide cover 
sprays from early season through early to mid-August 
frequently disrupts the control of these secondary pests. 
The "Second-stage" 1PM program currently being tested 
at the University of Massachusetts by the tree fruit ento- 
mologist, Ronald Prokopy, and the IPM coordinator, 
William Coli, however, has the potential to change this 
situation. The strategy replaces insecticidal control of 
apple maggot fly with a control system based on sanitation 
and intensive trapping. Second-stage IPM may allow 



routine, non-fungicidal sprays to be discontinued after the 
end of May. The termination of these disruptive sprays is 
expected to result in more mite predators and leafminer 
parasites in orchards, and these are expected, based on 
previous studies, to exert commercial-level control of these 
pests in most orchards. Preliminary results for one field 
season did show a substantial increase in predator mites 
when post-May, non-fungicidal sprays were not applied. 
We are, therefore, very likely to be at a major turning point 
in orchard pest control, in which the termination of con- 
tinuous cover sprays (the rule for at least 40 years) will 
usher in a mixed chemical/biological control strategy in 
which mite predators and leafminer parasites will provide 
control of these pests. 

There are a number of specific actions or studies that 
need to be undertaken to reach this goal. The most 
important is, of course, the second-stage IPM project itself, 
as it is the foundation on which all else rests. This effort 
currently is underway with primary funding from the 
Massachusetts Department of Food & Agriculture and the 
Massachusetts Society for the Promotion of Agriculture. 
Other specific actions that will be needed include the 
following. 

Mites . The composition of predacious mite fauna in 
Massachusetts apple orchards and their response to or- 
chard pesticides is fairly well understood (Hislop & 
Prokopy, 1981). The goal of increasing predator numbers 
in orchards to levels high enough to control spider mites 
can be reached by 1) earlier termination of cover sprays (as 
in the second-stage IPM strategy); 2) introducing a strain 
of the main pTcda\.OT,Amblyseiusfallacis, that has greater 
resistance to common cover spray insecticides; 3) planting 
and managing orchard floor vegetation that is most favor- 
able to predator mite survival and reproduction; and 4) 



avoiding the use of materials such as benomyl and the 
pyrethroids that do greater damage to predator mites than 
spider mites. Activity on point one is underway and 
a^'ditional funding for this effort is being sought from the 
Department of Food & Agriculture under the 
Department's competitive biological control grants pro- 
gram. A pesticide-resistant strain of Amblyseius fallacis 
does exist and has been established in apple orchards in 
Quebec where it has provided successful control of Euro- 
pean red mite and two-spotted spider mite (Bostanian & 
Coulombe, 1986). This resistant >1. /a//acw can be intro- 
duced in Massachusetts orchards. The role of orchard 
floor vegetation, the species of plants used and their 
management, is not well understood. Such vegetation 
influences winter survival of predators, the timing of their 
spring movement back into trees, and their rate of repro- 
duction, since plant pollens are used as food sources by the 
predator. A project to research this topic in Massachusetts 
has been funded by the Department of Food & Agriculture. 
Work was initiated in 1987 and will continue this year. 

Aphids and San Jose Scale . Generally, existing 
predators appear to keep the three aphid species in Mas- 
sachusetts apples under satisfactory control unless dis- 
rupted by pesticide use. The cecidomyiid, Aphidoletis 
aphidimyza, is one of the more important aphid predators, 
but various coccinellids, syrphids, and chamacmyiids also 
exist in important numbers. The apple aphid is the best 
studied of the three aphid species, and its control is 
predominantly by predators. The woolly apple aphid has 
a specific parasite, Apheliniis malt, that is important in 
regulating that species. Least is known about biological 
controls of the rosy apple aphid, one of the main aphid pests 
of apples. San Jose scale is attacked by a specialized 
parasite, Prospallella pemiciosi, of Asian origin, as well as 
various generalist predators. Future plans for control of all 
these pest species are based on the judgment that existing 
parasites and predators do exist that will control these pests 
in most cases unless disrupted by pesticide applications. As 
such, the second-stage IPM strategy should improve the 
degree and reliability of such control in the future. 

Leaftniners . The apple blotch leafminer is a classic 
induced pest. In unsprayed areas its densities are kept low 
by several efficient specialist parasites. In Massachusetts 
the major species are Pholetesor (Apanteles) omigis, a 
braconid, and the eulophid, Sympiesis marylandensis (Van 
Driesche & Taub, 1983). Both species feed on older larvae 
within mines. Under current orchard spray regimes these 
parasites become common in orchards only late in the 
season (August through October) after cover sprays are 
ended. When limited to this short period, parasites cannot 
suppress leafminers below economic levels. Terminating 
non-fungicidal cover sprays after the end of May, as envi- 
sioned by second-stage IPM, should create an opportunity 



for substantial increase in control of leafminer populations 
by parasites. Two additional parasite species have poten- 
tial for increasing the degree of leafminer control, the 
braconid, Apanteles pedias, from New Zealand and the 
encyrtid, Holcothorax testaceipes, from Japan. Both have 
been imported successfully into Ontario by fruit entomolo- 
gists at the University of Guelph and are established in that 
area. A. pedias also has been released in New York state. 
Dr. Chris Maier of the Connecticut Agricultural Experi- 
ment Station recently received funding to import and 
establish these parasites in New England. Studies in 
Massachusetts will be needed following releases to deter- 
mine the degree of control resulting from the introduction 
of these new species. 

In conclusion, biological control, while not applicable 
for plum curculio, apple maggot fly, or tarnished plant bug, 
in the future will play the key role in suppressing mites, 
leafminers, aphids, and San Jose scale. The principal way 
in which this control will occur will be through better 
conservation of existing predators and parasites by earlier 
terminationofregular cover sprays. Certain newbiological 
control agents, namely a pesticide-resistant strain of the 
predator m\{c, Amblyseius fallacis, and two exotic species 
of leafminer parasites, Apanteles pedias and Holcothorax 
testaceipes, should be introduced. As controls become 
increasingly based on predators and parasites, grower need 
for information on the recognition and biology of the 
specific beneficial species involved will increase. To meet 
this need, new Extension literature discussing the details of 
biological controls of specific apple pests will be required. 
Plans to develop such materials exist and are being sup- 
ported by funds from the Department of Food & Agricul- 
ture. 

References Cited 

Bostanian, N. J. and L. J. Coulombe. 1986. An integrated 
pest management program for apple orchards in south- 
western Quebec. Can. Enlomol. 118:1131-1142. 

Hislop, R. G. and R. J. Prokopy. 1981. Integrated 
management of phytophagous mites in Massachusetts 
(USA) apple orchards. 2. Influence of pesticides on the 
predator Amblyseius fallacis (Acarina: Phytoseiidae) 
under laboratory and field conditions. Prot.Ecol. 3:157-72. 

Van Driesche, R. G. and G. Taub. 1983. Impact of 
parasitoids on Phyllonorycter leafminers infesting apple in 
Massachusetts, USA. Prot. Ecol. 5:303-17. 

Van Driesche, R. G. and E. Carey (eds.). 1987. Opportu- 
nities for Increased Use of Biological Control in Massachu- 
setts. Mass. Agric. Exp. Sta. Bull. 718. 



**f« •X* *£• ^« 
^% 0^ #j» ^» 



Peach Brown Rot Fungicides Trial, 1987 

Daniel Cooley and James Mussoni 

Department of Plant Pathology, University of Massachusetts 

Joseph Sincuk 

Department of Plant & Soil Sciences, University of Massachusetts 

Two of the newer fungicides for peach brown rot Funginex 1.6 EC was used in 1 treatment at the lower 

control are Ronilan^^ (vinclozolin) and Rovral^^ (iprodi- end of the standard rate range (12 oz/100 gal), Rovral 

one). These materials are reported to be more effective 50WP was used at 0.25 Ib/lOO gal (1/2 the standard rate) 

than most other fungicides on peach brown rot. However, and Ronilan 50 WP was used in 3 treatments at 0.75 lbs, 0.75 

they are also more expensive than other materials. lbs plus the spray adjuvant X-77™, and at 0.5 lbs plusX-77 

Ronilan and Rovral are labelled and recommended (standard rate for Ronilan is 1 lb/100 gal). Treatments 
such that a lower rate may be used under low or moderate were scheduled at the discretion of the assistant orchard 
brown rot pressure. That means that when the weather is manager, and were done on the following dates under the 
relatively dry, then the lower rate may be used. We tested weather conditions listed: May 11-late petal fall (70°F, 
these materials at the lower label rates (and in one case, light breeze); May 26--post shuck split (85°F, light breeze); 
below the lowest label rate) in 1987, to see whether or not June 22--ripening fruit (85°F, humid, shower); July 6--not 
the low rates would perform as well as a low rate of Harbinger (75°F, clear, calm); and August 5--Glo Haven 
Funginex^^ (triforine), which has been an effective mate- only (80°F, clear, calm). Sprays were applied with a high- 
rial against brown rot for a number of years. We examined pressure handgun sprayer at a rate of 250 gal per acre, and 
the efficacy of the lower rates and analyzed it with respect trees were sprayed to the drip point, 
to the costs. The block consisted of three cultivars: Harbinger, 



Table 1. Treatments and rot ratings for 
Massachusetts, 1987. 


peach 


brown rot 


fungicide trial at the University of 


Treatment 




Harbinger 




Garnet 
Pre. 


Beauty 
(%) 


Glo Haven 1 


Pre.' 


Post." 


(%)« 


Pre. 


Post. (%) 


Ronilan 0.75 lb 
+ X-77 1% v/v 


0.0 a" 


1.3 a 


73 


0.1 a 


28 


0.0 a 


0.3 a 13 


Ronilan 0.75 lb 


0.1 a 


1.2 a 


70 


1.5 d 


33 


0.4 b 


0.3 ab 28 


Ronilan 0.5 lb 

+ X-77 1% v/v 


0.0 a 


1.5 ab 


85 


0.5 b 


39 


0.0 a 


0.4 b 20 


Rovral 0.25 lb 


1.0 b 


2.4 c 


93 


1.1 c 


22 


0.5 b 


0.6 d 39 


Funginex 12 oz 


1.3 b 


1.9 be 


82 


1.9 d 


26 


0.5 b 


0.4 c 23 


Control 


3.1 c 


3.4 d 


100 


1.6 d 


50 


0.8 c 


0.9 e 45 


^Mean number of brown rotted peaches per tree immediately prior to harvest. 

^Mean rot rating on to 5 scale (0 = no rot, 1 = < 10% rot, 2 = 10 to 25%, 3 = 26 to 75%, 4 = 76 to 

90%, 5 = > 90%) of a random box of approximately 40 fruit after 3 to 4 days at room temperature. 

"Percent of the harvested fruit showing any rot. 

"Means in a column not followed by the same letter are significantly different at odds of 19 to 1. 



8 



Garnet Beauty and Glo Haven. There were 2 randomly 
placed blocks of 4 trees of each cultivar in each fungicide 
treatment, for a total of 8 trees per treatment. 

At harvest, fruit on each tree were evaluated for the 
amount of rot present. All trees were mature (10 years) and 
were in adjacent rows in a block at the Horticultural 
Research Center (HRC), Belchertown, MA. Each cultivar 
was grown in two adjacent rows, 20 ft apart. Peaches were 
harvested, yield recorded, and a subsample of approxi- 
mately 40 random, apparently healthy fruit from each 
treatment were placed in a box and kept at room tempera- 
ture for 3 to 4 days. The fruit then were rated for the 
number of peaches which showed rot, and for the average 
intensity of the rot present, rated on a to 5 scale (0 = no 
rot, 1 = < 10% rot, 2 = 10 to 25%, 3 = 26 to 75%, 4 = 76 
to 90%, 5 = >90%). The postharvest ratings for rot 
intensity were not made on the Garnet Beauty fruit. 

All fungicide treatments had significantly less rot than 
the non-treated controls (Table 1). Harbinger has been 
particularly susceptible to postharvest brown rot at the 
HRC,asindicatedbythe 100% postharvest rot. Even in the 
treated Harbingers, there was some rot on between 70 and 
93% of the peaches. Ronilan treatments at the higher rate, 
either with or without X-77, significantly reduced rot 
intensity and preharvest rot. The 0.5 lb rate of Ronilan was 
slightly better than Funginex at reducing the rot intensity, 
but not the percent of rotted peaches. The 0.25 lb. rate of 
Rovral was equivalent to Funginex. Ronilan at either rate 
was significantly better than Funginex or Rovral at reduc- 
ing the preharvest rot. There was no difference between 
Ronilan treatments for preharvest rot on the Harbingers. 

In the other two cultivars, adding X-77 to the Ronilan 
at either the 1/2 rate or 3/4 rate significantly reduced the 
preharvest rot. Not adding X-77 depressed Ronilan's 
performance compared to that of Funginex. The 1/2 rate 
of Rovral was sometimes better and sometimes worse than 



the standard rate of Funginex. 

The best treatment for brown rot in this experiment 
was generally the 3/4 rate of Ronilan with X-77. The 1/2 
rate of Ronilan with X-77 also did reasonably well. The 1/ 
2 rate of Rovral was as good as the standard rate of 
Funginex. 

Does this mean that 3/4 or 1/2 rates of Ronilan may 
be substituted for other fungicides? Not really. This 
experiment indicates that in a season with moderate pres- 
sure, such as last year, the 3/4 and 1/2 rates of Ronilan or 
the 1/2 rate of Rovral will work as well as a standard rate 
of Funginex. The question remains, does Funginexwork as 
well as some of the older materials such as thiram and 
captan? Research in other states indicates that Funginex 
is at least as good as either captan or thiram, and that is why 
we used a Funginex standard. However, without including 
these materials in the test, we cannot be sure that captan or 
thiram would not have done better. This year we hope to 
repeat the test using captan or thiram. 

However, if Funginex at 12 oz is a good standard, then 
the lower rates of Ronilan not only did as well, but usually 
did better. In that context, reduced rates of Ronilan can do 
as well as or better than Funginex, and therefore might be 
considered as an alternative to a full rate of Funginex. 
However, the economics of the situation do not necessarily 
favor even the reduced Ronilan, Rovral, or Funginex 
treatments. For the season (given 3 applications for brown 
rot), the cost of Ronilan at the low rate was $114.00/acre 
more than captan; at the 1/2 lb. rate, Ronilan cost $66.00 
more than captan (Table 2). Funginex at the 12 oz rate cost 
$25.50 more than captan. Rovral at the 1/4 lb rate cost 
$15.00 more than captan. Since 3 applications is a low 
estimate, the cost difference in many cases would be 
greater. In short, a full rate of captan is always much less 
expensive than the newer materials. Among the materials 
tested, Ronilan is more effective, yet it is also several times 



Table 2. List of retail prices for fungicides at recommended and decreased rates (January, 1988). 



Material 



High rate^ 



Cost 
per acre'' 



Low rate 



Cost 
per acre 



Reduction 
per acre" 



Cost comp. 
to captan 



Ronilan SOW lib $192.00 3/4 lb $144.00 $48.00 +$114.00 

Ronilan 50 W 1 lb $192.00 1/2 lb $%.00 $96.00 + $66.00 

Rovral 50 W 1/2 lb $90.00 1/4 lb $45.00 $45.00 + $15.00 

Fungmex 1.6 EC 16 oz $74.25 12 oz $55.50 $18.75 + $25.50 

Captan SOW 21b $30.00 21b $30.00 $0.00 + $0.00 

Ter 100 gal. 

Iligh rate of material in 250 gal, 3 applications; January, 1988 approximate prices from retail source. 

"Dollars saved by using the reduced rate for 3 applications. 



as expensive. 

If the increased control can more than pay for itself, it 
is worthwhile. For example, if the material reduces the 
number of rotted peaches by 1 peach per tree, it will 
increase the production of an acre of peaches by approxi- 
mately 1 bushel. This result will earn an extra $15.00 to 
$20.00. Ifthepostharvestrotisdecreased, extramoneyand 
extra customer satisfaction will be added. If this extra 
money exceeds the extra material cost, obviously the treat- 
ment is worthwhile. 

By those criteria, our data from last year indicated that 



the Ronilan treatments were not economically justified. 
However, it is important to stress that this is only one year, 
and that we do not know how well captan might have 
controlled brown rot. In addition, this analysis does not 
consider what might happen under heavy brown rot pres- 
sure. 

This year we hope to carry out the economic analysis 
more completely and include captan treatments for com- 
parison. Only by determining the ultimate Tmancial benefit 
can we judge whether or not a more effective chemical is 
indeed a more cost effective fungicide. 



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Mauget Microinjection for Peach X-Disease Therapy 



Julianne Schieffer, Terry A. Tattar, and Daniel R. Cooley 
Department of Plant Pathology, University of Massachusetts 



Introduction 

Since the first report in Connecticut in 1933, X-disease 
has become a serious disease of peach. Originally thought 
to be caused by a virus, X-disease was shown to be caused 
by a mycoplasma-like organism living in the phloem. 
Infection occurs from chokecherry to peach through trans- 
mission by leafhoppers. 

An infected tree breaks out of dormancy with healthy 
foliage and flowers. After seven to eight weeks, sections of 
the tree begin to show a diffuse yellowing. Soon the leaves 
become brittle, develop red spots, tatter, and curl upward. 
Diseased leaves fall, often leaving a rosette of yellowed, 
dwarfed leaves at the tip of each infected branch. This 
process produces a "rat tailing" effect as the terminal bud 
breaks prematurely. Diseased trees have reduced growth 
and lower yields. Unaffected scaffolds within the same tree 
may continue to grow and bear, but this fruit often lacks 
flavor or is bitter. Death of the tree, or winter kill of 
affected sections, often follows within one to four years. 

Attempts to control peach X-disease have had mixed 
results. Pruning diseased limbs is not successful, as the 
disease appears on other limbs the following year. Chemo- 
therapy of X-disease with oxytetracycline (OTC) has 
shown much promise, but traditional injection methods 
have a number of disadvantages. Injection techniques such 
as gravity infusion, pneumatic pressure, and pipettes, have 
proven labor intensive, ineffective, or detrimental to tree 
health (Lacy, 1982; Rosenbergcr & Jones, 1977). Mauget 
microinjection has been used widely to deliver effectively 



chemicals to shade trees with little injury. The objective of 
this study was to determine if Mauget microinjection of 
oxytetracycline could be used in commercial peach or- 
chards for remission of peach X-disease symptoms. 

Materials and Methods 

The Mauget microinjection system consists of a small 
disposable capsule. In our research, these capsules con- 
tained 4 ml of 4% OTC solution. Each capsule is attached 
to a beveled feeder tube and pressurized with a mallet to 
approximately 10 to 12 pounds per square inch. One or 
more 3/16 inch holes, depending on tree diameter, are 
drilled approximately 1/2 inch deep at the tree base with a 
portable drill. The capsules are inserted immediately and 
tapped with the mallet to break the internal membrane, 
thereby forcing the OTC solution into the xylem of the tree. 
The appropriate dose rate is one capsule per two inches of 
trunk diameter. Most trees in this study received 2 or 3 
capsules. The contents of most of the capsules was taken 
up by the tree within a few hours. Empty capsules were 
removed within a week. 

Four Massachusetts orchards were chosen for injec- 
tion in September, 1986. Each diseased tree and each 
healthy control tree was rated with the following scale: = 
outwardly healthy, 1 = foliar symptoms on 10% or less of 
the canopy, 2 = symptoms on 10 to 50% or less of the 
canopy, 3 = 50 to 90% affected, and 4 = over 90% affected 
or dead. Approximately half the trees in each rating class 
then were injected after fruit harvest. 



10 



Trees were observed throughout the following grow- 
ing season for symptom remission, yield, and wounding. In 
September, 1987, every tree was rerated to determine any 
change due to treatment or to progress of the disease. 

Results 

As indicated by the rating changes shown in Table 1, 
most X-disease symptoms on the OTC-treated trees were 
either absent or less severe. Untreated controls either 
remained at the same disease level, or grew worse when 
compared to the previous year's ratings. Of the untreated 
trees with an initial rating of (healthy), 47% showed an 
increase in X-disease symptoms. Trees with initial disease 
ratings of 1 or 2 responded well to the OTC treatments, 
often bearing as much fruit as healthy trees. The severely 
diseased trees with ratings 3 and 4 gave variable results. 
Many treated and untreated trees of the 3 and 4 rating 
classes became worse or died. Even among those trees 
responding to the treatment, most had only one or two live 
scaffolds bearing fruit. 

Observations throughout the season showed that most 
treated trees in rating classes to 2 had good fruit yields. 
Untreated trees gave a wide range of yields dependent 
mostly on the extent to which the crown was affected by X- 
disease. 

Some trunk damage associated with the drilled holes 
was evident a year after treatment. Over 60% of the holes 
inspected had small cracks or gummosis associated with 
the injection site. A few trees had extensive cracks (from 
6 to 10 inches) and decay. Fourteen percent of the holes 
had callused over after a year and a half. The injection 
wound alone did not cause the cracks and gummosis; they 



were caused by the OTC treatment (Schieffer, unpublished 
data). 

Discussion 

Mauget microinjection of OTC appears to be an 
effective and simple technique for X-disease therapy de- 
spite possible long-term drawbacks related to injection 
wounds. Microinjection is not labor intensive and does not 
require special equipment. Since most X-infected trees 
decline quickly and eventually die, treatment of diseased 
trees may at least prolong their productivity. However, 
trees not more than half affected responded the most, 
therefore, Mauget therapy appears to offer limited effec- 
tiveness to trees in advanced stages of X-disease. Injections 
will be most cost-effective where half of the tree or less is 
affected by foliar symptoms at the time of treatment. 

Mauget microinjection may prove especially valuable 
in delaying symptom development in asymptomatic trees 
on sites where high disease pressure from infected choke- 
cherries is present. Treatment of healthy trees, on the 
other hand, may need to be considered carefully because of 
the possible long-term wound effects from OTC injection. 

Research is continuing on the evaluation of risks vs. the 
benefits of prophylactic use of this method in healthy trees, 
and to determine how long treated trees remain in symp- 
tom remission. 

References 

Lacy, G.H. 1982. Peach X-disease: Treatment site damage 
and yield response following antibiotic infusion. Plant 
Disease Reptr. 66:1129-1133. 



Table 1. Changes in 


X-disease ratings following OTC treatment. 








Original rating 


Treatment 


Increase 


(%) 


No change 


(%) 


Decrease (%) 





OTC 


9 




91 










Control 


47 




53 







1 


OTC 


5 




19 




76 


1 


Control 


73 




13 




13 


2 


OTC 







20 




80 


2 


Control 


17 




75 




8 


3 


OTC 


14 




7 




79 


3 


Control 


10 




70 




20 


4 


OTC 







67 




33 


4 


Control 







100 







I 



11 



Rosenberger, DA., and A.L. Jones. 1977. Symptom remis- 
sion in X-diseased peach trees as affected by date, method, 
and rate of appUcation of oxytetracycHne-HCL. Phytopa- 
tholoQ> 67:277-282. 



Acknowledgements 

The authors wish to thank Hamilton Orchards in New Salem, 
Westward Orchards in Harvard, Bolton Spring Orchards in Bolton, and 
Green Acres Fruit Farm in Wilbraham for their cooperation during this 
study. We also thank James Williams and Karen Hauschild for help with 
injections, and the J. J. Mauget Company for supplying the Mauget OTC 
capsules. 



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Reevaluation of NAA as a Preharvest Drop Controlling 
Chemical for Mcintosh 



Duane W. Greene 

Department of Plant & Soil Sciences, University of Massachusetts 



For the past 20 years Alar^^ has been the primary 
chemical used to control preharvest drop of Mcintosh fruit. 
The superior performance of Alar essentially eliminated 
the use of those compounds available prior to its registra- 



tion. However, the registration of Alar is under review and 
we still do not know what its future will be. More stringent 
tolerance levels already have been set by the Massachusetts 
Department of Public Health. 





Cumulative drop (%) 






100 






.^-— « 




-^ Control 


^^ 




-I- NAA (10 ppm) 


^ft^"^^^ 






80 


- -^ NAA (20 ppm) 


cJ^^^^ ^x.———- 


H — ' — *" 




60 


-B- Alar (750 ppm) 


J^ j^^'^^^^ 


^ 




- 


//y^ 


40 


/Jj€^ 






20 


itJTi 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 t 1 1 1 1 1 1 t 


1 1 1 1 1 1 




■ 1 1 1 t- 

Sept 2 Sept 11 Sept 20 Sept 29 Oct 8 


Oct 17 


Figure 1. Cumulative drop from trees which received Alar, NAA (10 or 20 ppm 
ber 8), or no drop-controlling treatment. 


on Septem- 



12 



The only other drop-controlling chemical that is reg- 
istered for use on apples is naphthaleneacetic acid (NAA). 
If growers in Massachusetts must depend on this com- 
pound, then a reevaluation of its effectiveness is necessary, 
since most of the research on NAA was done prior to 1960. 
Pruning and training systems, pest control programs, root- 
stocks, orchard management practices, and fruit condition 
requirements have all undergone significant changes since 
that time. 

A study was initiated in 1987 to answer several specific 
drop control questions: 1. How effective is NAA at 
controlling preharvest drop of Mcintosh? 2. How long 
does drop control from NAA last? 3. Can growers first spot 
pick then effectively control drop with NAA? 4. How much 
drop occurs as a result of harvesting? 

A block of 11-year-old Rogers Mclntosh/M.26 were 
selected and divided into 8 groups of 8 trees each. Two 
trees in each group were sprayed with 750 ppm Alar (2.25 
lbs per acre) on July 17, 1987. When the first sound fruit 
began to drop on September 8, NAA at 10 and 20 ppm was 
applied to a tree in each group. This timing is recom- 
mended on the NAA label. It was decided that September 



14 was the day that a commercial grower would begin spot 
picking these trees. All fruit that had sufficient color to 
meet the U. S. Extra Fancy grade were harvested from half 
of the trees in each block. On September 15 NAA at 10 or 
20 ppm was applied to a portion of the trees that were 
previously spot picked. Drops were removed from under 
trees prior to and immediately after spot picking. All drops 
were removed 3 to 4 times weekly from September 1 to 
October 2 and then twice weekly until the experiment 
ended on October 20. 

The NAA label recommends that application should 
begin as soon as the first sound, uninjured fruit begin to 
drop. This timing occurred on September 8. Whenapphed 
at this time 10 ppm NAA was as effective as Alar at 
controlling drop for 8 days, and 20 ppm NAA was as 
effective as Alar for 10 days (Figure 1). After 10 days Alar 
was clearly the superior drop controlling chemical. Cumu- 
lative drop on trees receiving NAA was significantly less 
than on control trees, even as long as 6 weeks after 
application. Although fruit quality was not evaluated in this 
experiment, it was noticed that fruit receiving NAA were 
noticeably softer and riper at the end of September. 



Cumulative drop (%) 



100 



80 



60 



40 



20 



-e- 


Control 


-h 


NAA (10 ppm) 


-^ 


NAA (20 ppm) 


-B- Alar (750 ppm) 



I I I I I I I I 



Sept 2 



Sept 1 1 




I I I I I I I I I I I I I I I I I I I I I I I I I I 



Sept 20 



Sept 29 



Gets 



Oct 17 



Figure 2. Cumulative drop after spot picking on September 14 from trees which received 
Alar, NAA (10 or 20 ppm on September 15), or no drop-controlling treatment. 



13 



100 



Cumulative drop (%) 




Sept 13 



Sept 22 



Octi 



Oct 10 



Oct 19 



Figure 3. Cumulative drop after September 14 from trees that were or were not spot picked 
on September 14 and received Alar or no drop controlling-treatment. 



Growers may wish to delay the appHcation of NAA 
until they make their first harvest. This delay will allow the 
filling of CA storages with fruit that has the potential for 
long-term storage. When application of NAA was delayed 
until trees were spot picked (September 14), it took ap- 
proximately 6 days for drop control to be effective (Figure 
2). During this period, over 25% of the fruit on NAA- 
treated trees dropped. Once drop control was established, 
NAA retarded drop for a long period of time. The results 
of this experiment confirm the results of a similar experi- 
ment done in 1986. In that study NAA was applied on 
September 13 when drop exceeded 10%. It required 9 days 
for NAA to slow drop significantly, and by that time over 
20% of the crop had been lost. 

Spot picking removed about 39% of the crop. Even 
though these trees were relatively small and are not difficult 



to pick, 6% dropped as the result of harvesting process. It 
has been suggested that partial crop removal may reduce 
drop. It is reasoned that the more mature fruit that are 
prone to drop will be removed by spot picking. Also, the 
snowball effect of one dropping fruit hitting another will be 
reduced. Harvest did not reduce the amount of drop from 
untreated trees (Figure 3). However, if trees were previ- 
ously treated with Alar, crop removal did retard drop. The 
reason for this is not clear. 

Summary . If NAA was applied when the first sound 
apples started to drop it retarded drop effectively for 7 to 
10 days. If NAA application was delayed until trees were 
spot picked and drop was proceeding, it took up to 6 days 
to slow drop. Over 25% of the crop was lost before drop 
control was established. 



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14 



Postharvest Apple Rots: Dr. Rosenberger's Approach 



Daniel R. Cooley 

Department of Plant Pathology, University of Massachusetts 



Dr. David Rosenberger of the Hudson Valley Lab, 
Cornell University, has been studying postharvest rots on 
apples for a number of years. In a recent talk at the 
University of Massachusetts he discussed some of the key 
points in the management of these problems, and these 
points will be outlined in this article. Dr. Rosenberger 
emphasized that the key to good management was an 
integration of several techniques: 

* Appropriate and sufficient summer fungicide applica- 
tions; 

* Good management of the harvesting process; 

* Appropriate postharvest chemical use in the dip tank; 

* Good sanitation in the storage facility and harvest proc- 
ess; and 

* Intelligent use of storage and marketing options. 

Fungicide Applications During the Growing 
Season 

Good storage rot control begins in the field before 
harvest. For example, last summer the wet harvest tem- 
peratures, combined with a tendency to leave fruit on the 
tree for color development, produced a larger than normal 
amount of rot in storage. This situation occurred because 
the wet weather during summer and harvest increased the 
rot inoculum and unseen fruit infections. 

There are a number of diseases, rots and others, which 
can develop in storage: 

Pin-point scab can be a problem. Late-season scab 
infections on the fruit can go undetected, and develop in 
storage into visible lesions. The best way to avoid a 
problem is to maintain good scab management throughout 
the season. 

Sooty blotch and fly speck are late season problems that 
may develop if summer weather conditions are humid. 
Interestingly, the fungi which cause these diseases will not 
grow at storage temperatures. However, unseen infections 
on harvested fruit can develop in storage. The fungi grow 
duringthe period when the fruit is cooling, before it reaches 
the storage temperature. In a large storage room, where it 
may take several days to reach the desired temperature, the 
fungi grow well for a time. Rapid cooling after harvest 
would help eliminate this problem. 

Moldy core is another disease which develops in the 
field, and lies undetected until the fruit has been in storage. 
Moldy core can be caused by a number of fungi, but about 
90% of the problems are caused by Altemaria. The 
infections occur during bloom and petal fall. Unfortu- 



nately, there do not seem to be any fungicides which control 
the disease very well. The infections develop inside the 
fruit, largely protected from fungicides. 

Fungicides can help reduce many of the other posthar- 
vest rots. A minimum program of 1 appUcation in early July 
and 1 again in early August should be adequate to control 
development of most of the late season fungal infections. 

Management During Harvest and Packing 

Wounded or over-mature fruit are more susceptible to 
postharvest diseases. For example, a rough orchard road 
can lead to significant quantities of wounding, which will 
increase the fruit's susceptibility to rot. Taking the time to 
smooth the orchard floor can reduce this problem. Avoid 
storing over-mature fruit. Ingeneral, the most mature fruit 
should be marketed first, and the less mature stored. 

As mentioned above, rapid cooling can decrease the 
time that rot fungi have to develop. In some cases, it will 
stop development completely, while in others it will slow 
the process. Rapid cooling slows down fruit ripening, 
which slows down all forms of fruit rotting since fruit lose 
their resistance to fungi as they ripen. 

Another management practice which affects posthar- 
vest rots as well as storability is calcium nutrition. Low 
calcium in the fruit increases its susceptibility to rot organ- 
isms. Perhaps other nutrients, such as potassium also can 
affect rot susceptibility. Maintaining a calcium nutrition 
program is advisable. 

Sanitation 

Attention to sanitation can be beneficial at all points in 
the postharvest handling process. The basic aim is to keep 
the inoculum for postharvest rots away from the fruit. 

Old bins can contain bits of old, rotten fruit from the 
previous year. Designating a single bin for culls can reduce 
the spread of this inoculum. Soaking a bin with bleach 
solution (10% in water) mixed with either detergent or a 
standard spreader-sticker, and allowing the bin to air dry 
also will reduce problems. 

Dirt from the orchard fioor also can carry inoculum. 
To counter this problem, keep bins on sod and away from 
direct soil contact. Do not operate equipment so that it will 
dig up soil when a bin is Ufted. In wet weather, rigging a 
hose to wash trucks, trailers, and bins wiU reduce the 
amount of soil which is carried into the drench solution. 

Reducing the inoculum load in the drench solution is 
very important, since it comes in contact with virtually all 



15 



the fruit. Besides using an equipment prewash, it is 
advisable to change the drench solution frequently. Since 
disposing of the solution is a problem, minimizing the 
voluir; of solution used in the drench equipment can 
contribute to overall efficiency. For example, it would be 
better to develop a system using 15 gallons of rapidly 
recirculating drench, and change it daily, than to use a 200 
gallon system for weeks. 

Given that you have a large volume system, the holding 
tank should have rounded corners rather than square 
corners. Square corners are "dead" areas, where fungicide 
can settle out of solution. Keepingthe solution agitated and 
the chemicals in solution is critical to maintaining proper 
application rates. Placing rounded baffles in a square tank, 
or using a rounded tank, can solve the problem. 

Fungicides 

There are only a few fungicides registered for posthar- 



vest use. These include the following materials: Captan 
SOW™, Captan SOW™, Benlate 50W^, Topsin 70W™, 
and Mertect 340- F™. Captan is only moderately effective. 
Benlate, Topsin, and Mertect ju^e very effective, but can 
become ineffective when fungal resistance develops. 
Rosenberger observed that these fungicides appeared to 
control rot better when used in combination with DPA 
(diphenylamine) than did either the fungicides or the DPA 
alone. When he tested the fungicides and DPA against 
benomyl-resistant Penicillium, he discovered that DPA 
inhibited the fungus. However, benomyl-sensitive isolates 
of Penicillium were inhibited only marginally by DPA. 
Most Penicillium isolates were sensitive to either DPA or 
fungicide. Hence, in a mixed set of resistant and sensitive 
fungal spores, such as would be expected in natural condi- 
tions, the majority of the fungi would be affected. Interest- 
ingly, the DPA is effective at low temperature (about 35°F) 
but not at room temperature. 



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Electric Lift Truclcs in Refrigerated Facilities 

James F. Thompson 
University of California, Davis 



New Battery Desig ns. Although electric lift trucks cost 
60% more than equivalently sized propane-powered Uft 
trucks, many cold storage and precooling operations are 
buying electric lifts for work inside refrigerated areas. One 
reason for the switch is that new battery designs allow 
electric lifts to operate for a full 8-hour shift in these 
operations. But, more importantly, the savings in energy 
and maintenance costs will more than pay for the extra cost 
of an electric lift over its economic life. 

Energy Cost . A 5,000 pound capacity Uft truck will cost 
$23,000 if battery-powered (this includes a charger and a 
battery with a 6,000-hour life) . An electric lift uses electric- 
ity for battery charging. But an electric lift produces less 
waste heat than a propane lift, so refrigeration for remov- 
ing lift truck heat is much less. Seven tons of refrigeration 
capacity are needed to remove waste heat produced by a 
propane lift, while only 2.5 tons are needed for electric lifts. 
In addition, most of the electricity use for electric lifts is at 
night when electric rates are often lower. 

The net effect is that electricity costs are equal for the 
two types and total energy savings for electric compared 
with propane are equal to the cost of propane for the 
propane lift. To estimate propane savings, assume a 5,000 



pound lift truck uses about 1 gallon of propane per hour. 

Low Maintenance . Electric lifts have much lower 
maintenance costs than propane lifts. Lift truck manufac- 
turers' estimate maintenance costs for propane powered 
trucks to be $2.50 per hour of operation, while maintenance 
costs for electric lifts trucks are an equivalent of only $1.00 
per hour of operation. 

For many operations, the energy and maintenance cost 
savings of electric lifts will more than pay for the higher 
initial and battery replacement cost of electric lift trucks. 

No Ethylene Gas No Carbon Monoxide . An impor- 
tant added benefit of electric lifts is that they do not produce 
ethylene gas as propane lifts do. Ethylene can cause 
premature ripening in some crops, and postharvest disor- 
ders such as russet-spotting in lettuce. Also, electric lifts do 
not produce the carbon monoxide which can be a safety 
concern if a refrigerated, enclosed facility does not have 
adequate ventilation. 

Reprintedfrom Perishables Handling Newsletter, Coopera- 
tive Extension, University of California. No. 62, October, 
1987. 



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16 



Potential for Explosions in CA Storage Facilities 



Henry Waelti and Eugene M. Kupferman 
Washington State University 

A certain amount of risk is involved when using 
combustible gases to generate CA atmospheres. This risk 
can be minimized if users understand the principles of 
operation of CA equipment so that they can take the 
needed precautions. 

The common gases used in CA generators arc propane 
and natural gas. Both fuels can be ignited by a spark or 
flame if they are allowed to accumulate to certain concen- 
trations and if sufficient oxygen is present. 

Explosive Limits 

The limits of gas-to-air ratios between which explo- 
sions can occur are expressed as lower explosive limit 
(LEL) and upper explosive limit (UEL). Outside of these 
limits there is no danger of explosion. For propane they are 
2.2% (LEL) and 9.5% (UEL). This means that if there is 
less than 2.2% propane in a room, there is not enough fuel 
to explode, or if there is above 9.5% propane in a room, 
there is not enough oxygen present to allow an explosion. 
(For natural gas, the LEL is 5.3% and the UEL is 14%.) In 
addition to the gas, a minimum of 11% oxygen is required 
to create an explosion with propane. 

Open Flame Burners 

In open flame burners, without catalytic converters, it 
is essential that the correct amount of gas is used to obtain 
complete combustion (4.2% propane in normal air). If the 
ratio of gas to air is lower, or higher, incomplete combus- 
tion occurs, resulting in production of carbon monoxide 
and ethylene gas, which are detrimental to fruit quality. 
Also, carbon monoxide may leak through walls, accumu- 
late in work areas, and create a health hazard to workers. 
Fortunately, there are few of these burners left. 

Inert Gas Generators 

Inert gas generators, such as Tectrol and Isolcell, 
produce an inert gas by direct and catalytic combustion of 
fresh air and propane or natural gas. As long as the fuel- 
air mixture remains at the correct ratio and the catalyst is 
working properly, complete combustion is assured. 

Recirculating 

In recirculating systems, such as the catalytic oxygen 
burners (COB), the fuel is oxidized on a catalytic surface 
without a flame. As in the open flame burners, enough 



oxygen must be available to combine with ALL the fuel 
present. Thus, as the oxygen level in a storage decreases, 
the fuel supply must also be decreased. Although catalytic 
oxidation of fuel may occur without a flame down to 0.5% 
oxygen, these burners should not be operated below 3% 
oxygen. With the proper gas-to-air ratio in the COB, the 
operating temperature of the catalyst is 1100°F to 1300°F. 
This temperature range will be maintained as long as the 
fuel and air flow remain at the proper setting and the 
catalyst remains functional. A properly designed and 
operated catalyst allows the fuel to be oxidized completely 
down to an operating temperature of 1000°F. If a minimum 
operating temperature of lOOO'F cannot be maintained at 
the recommended fuel and air ratio, then the catalyst may 
be defective and may need to be replaced. 

Accident Prevention 

-Purchase a propane/methane monitor. They can be 
installed on the burner to monitor the effluent stream. 
Portable units can be used to monitor individual rooms for 
combustible hydrocarbons and other gases toxic to workers 
and detrimental to the fruit. It usually is NOT possible to 
detect propane or natural gas by smell. 

-In early summer, have a competent technician check 
out all CA equipment so that there is enough time to make 
the necessary repairs before the storage season. These 
tests should include the use of portable gas analyzers to 
monitor fuel/air ratios and combustion efficiency. 

-CA generating equipment must be operated and 
maintained according to manufacturer's instructions at all 
times. 

-Low temperature fuel cut-offs on recirculating burn- 
ers should not be set below the manufacturer's recommen- 
dations, which is usually 1000°F. 

-Check all safety devices at the start of equipment 
operation, including low and high cutoff thermostats, sole- 
noid valves, fuel regulators, and air pressure switches. 

-Do NOT turn on the fans and open the door when 
bringing up the oxygen in a room if there is a suspicion of 
gas in the room. 

-A recommended procedure when opening a room is 
to scrub out the combustible gases that may be present in 
the room atmosphere using the COB catalyst. Bring up the 
oxygen level in the room to 5%. Turn off the fuel supply to 



17 



the COB and set it on preheat. Run the temperature up to 
600°F and recirculate the CA room atmosphere through 
the generator. The temperature of the catalyst may rise, 
and if ^vill remain hot until the combustible gas (propane 
or natural gas) is down to a s£ife level. 

-Some storage operators routinely use a COB to scrub 
out any combustible gas which may have entered a CA 
room during pulldown. 



It is possible to reduce risks to a minimum. By 
understanding the principles of CA generator operation, 
maintaining the equipment and safety devices, and using 
the available instrumentation, managers can maintain a 
clean and safe storage atmosphere. 

Reprinted from Postharvest Pomology Newsletter, Wash- 
ington State University, March, 1988. 



*9Sm »3^ %|» «£# 
w^ ^* ^* '^^ 



An "Expert System" for CA Storage of Mcintosh Apples 

William J. Bramlage 

Department of Plant & Soil Sciences, University of Massachusetts 



Our recent survey of CA storage operators in Massa- 
chusetts indicated that many storages are not being oper- 
ated at conditions that are most suitable for Mcintosh 
apples. Factors that can contribute to this situation include 
not recognizing the importance of certain conditions, or 
overlooking details during the hectic harvest period. 

To try to provide easy access for storage operators to 
critical information, and to create a mechanism for self- 
evaluation of storage operations, we are developing an 
"Expert System" for CA storage of Mcintosh apples in 
New England. This system is a series of questions, with 
answers to be provided by the storage operator, followed by 
advice about how long the apples reasonably can be ex- 
pected to retain quality in storage, the potential for storage 
disorders resulting from some adverse storage condition, 
and corrections that might be made when an adverse 
condition is recognized. 

This "Expert System" is a computer program on a 
floppy disk that can be operated on any IBM-compatible 
personal computer. It will come with directions for activat- 
ing and operating the program, and will require only the 
availability of an IBM"^-compatible personal computer 
with 640 kbyte memory capacity, and the rudimentary 
knowledge for operating the computer. 

This system was developed by A. Zubin Varghese, a 
graduate student in our Department of Food Engineering, 
through a series of intense interviews with the author. Mr. 
Varghese worked with Ernest Johnson and Lester Whit- 
ney, in the Department of Food Engineering, to convert the 
information from these interviews into a computer pro- 
gram. This Expert System depicts the author's best judg- 
ment of CA storage conditions for Mcintosh apples in 
Massachusetts, but in a broader sense provides informa- 



tion about storage responses of apples to varying condi- 
tions. Its format is a series of "If ... Then ..." situations and 
its primary goal is to provide information to help reduce 
losses of apples during and following storage. 

The questions in this program first attempt to establish 
the potential of a set of apples for storage based on maturity 
at harvest, speed of cooling, time required to fill and seal a 
CA room, and time required to generate the CA atmos- 
phere. Then, the storage operator is questioned about the 
conditions that are being maintained within the CA room, 
including unintended deviations from recommendations. 
Where less-than-desired conditions exist, suggestions for 
"what might have been" are given. Where risks of physio- 
logical disorders are recognizable, these risks are quanti- 
fied, the potential disorder is described, and possible 
corrective actions are recommended. The program is 
accompanied by a printed text describing the kinds of 
information needed to answer the questions, and the 
recommended ways of obtaining this information. 

This "Expert System" is new and needs testing to see 
how useful it is and how it might be improved. It is primarily 
intended as an educational tool, a readily available source 
of information. We hope to have it available for trial by late 
summer, and to offer it through the University of Massa- 
chusetts Cooperative Extension for a small fee to cover 
expenses. 

We hope that some CA storage operators will be 
willing to try the system and to help us evaluate its useful- 
ness and possible improvements. If you are interested in 
obtaining and evaluating this "Expert System" if it is 
available by late summer, please contact the author or Dr. 
Wesley Autio, at your earliest convenience. 



* ^£# ^^ ^}i* *S* 
v|* vjv v{* *»^ 



18 



I New England 

Apple Production Guide 




Cost: $4.00 per copy. 



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Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

University of Massachusetts Cooperative Extension, ' *"' ' ' ' A O O . 

United States Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R. Autio and William J. Bramlage 



ISSN 0427-6906 



BIOLOGICAL 

OCT 06 1988 



bCltNCES LiBKAHY 




Volume 53, Number 4 
FALL ISSUE, 1988 

Table of Contents 

Improving the Growth of Newly Planted Apple Trees 

The Effects of Travel Speed, Nozzle Arrangement, 

and Application Volume on Pesticide 

Distribution in Apple Trees 

Biological Control of Apple Blotch Leafminers 
in Massachusetts Apple Orchards 

Controlling Spider Mites in Massachusetts Apple 
Orchards Through Conservation of Predator Mites 

Comparing Costs of Rubigan^^ and Conventional Fungicides 

Apple Bruising. I. Evaluating Grading Lines 

An Assessment of CA Storage Operations in Massachusetts 

A User-built System for Automated Monitoring 
and Controlling of CA Apple Storages 



/T 



Fruit Notes 

Publication Information: 

Fruit Notes (ISSN 0427-6906) is published the first day of January, 
April, July, and October by the Department of Plant & Soil Sciences, 
University of Massachusetts. 



The costs of subscriptions to Fruit Notes are $4.00 for United States 
addresses and $6.00 for foreign addresses. Each one-year subscrip- 
tion begins January 1 and ends December 31. Some back issues are 
available for $1.00 (United States addresses) and $1.50 (foreign 
addresses). Payments must be in United States currency and should 
be made to the University of Massachusetts. 



Correspondence should be sent to: 

Fruit Notes 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

University of Massachusetts 

Amherst, MA 01003 



COOPERATIVE EXTENSION POUCY: 

All chemical uses suggested in this publication are contingent upon continued registration. Thesechemicals should be 
used in accordance with federal and stale laws and regulations. Growers are urged to be familiarwith all current state 
regulations. Where trade names are used for identification, no company endoreemeni or product discrimination is 
intended. The University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied, 
concemingthe use of these products. USER ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY 
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Issued by the Unhrrsity ofMassachusells Cooperatiw Extension, E. B. MacDougoU, Director, in furtherance of the acts of 
May 8 andJune 30,1914. The Unix-ersily ofMassachusetIs Cooperative Extension offers equal opportunity in prop-ams and 
employment. 



Improving the Growth of Newly 
Planted Apple Trees 

Wesley R. Autio and Duane W. Greene 

Department of Plant & Soil Sciences, University of Massachusetts 

Daniel R. Cooley 

Department of Plant Pathology, University of Massachusetts 



It is well accepted that to be profitable an orchard 
enterprise must receive returns from new plantings as 
early in the life of those trees as possible. Rootstocks and 
cultivars are major factors determining the age at which an 
orchard begins to pay for itself. Site preparation and 
cultural practices prior to, during, and after planting also 
influence the age at which a tree comes into production. 

At the University of Massachusetts Horticultural 
Research Center in Bclchertown we generally do not 
obtain a desirable amount of growth the year of planting, 
and it must be recognized that to obtain early returns and 
maintain high profitability throughout the life of a block it 
is necessary for the trees to grow well and produce a good 
fruiting framework in the years just after planting. Site 
preparation techniques, such as cover cropping, organic 
matter incorporation, and installation of irrigation or 
drainage, are known to improve growth. We decided to 
study planting and post-planting techniques which may 
offer some benefit to tree growth. 

Level of Nitrogen Fertilizer 

In 1986 four plantings were established at the Horti- 



cultural Research Center. The first planting (Marshall 
Mclntosh/M.9) assessed the effects of different levels of 
nitrogen fertilizer applied soon after planting. It was 
postulated that additional growth could be obtained if 
nitrogen was applied at higher rates than usually recom- 
mended. In 1986 individual trees received either 0.5, 1.0, 
1.5, or 2.0 pounds of ammonium nitrate in split applica- 
tions two weeks apart approximately two weeks after 
planting. Treatments were repeated in 1987; however, the 
2.0-pound rate was decreased to 1.5 pounds because of 
tree injury noticed in 1986. Trunk circumference was 
measured at planting and after the 1986 and 1987 grovving 
seasons. Total shoot growth was measured after the 1986 
and 1987 growing seasons. Data are reported in Table 1. 
In 1986, increasing the amount of ammonium nitrate 
beyond the standard rate of 0.5 pound decreased trunk and 
shoot growth. Even in 1987, the second leaf, growth was 
decreased when the rate of application was increased. We 
can postulate that root injury occurred in 1986 which 
carried over to 1987, and that we cannot attempt to 
improve tree growth with increasing nitrogen applications. 
Furthermore, these results suggest that we should re- 
examine our present recommendation of 0.5 pound of 



Table 1. The effects of different levels of i 
planted in 1986. 


litrogen fertilization on the growth of Marshall Mclntosh/M.9 trees 


Ammonium 
nitrate 
1986/1987 
(lbs/tree) 


Trunk circumference (cm) 


Change in 


trunk circ. (cm) 


Shoot growth (cm) 


At planting 1986 1987 


1986 


1987 1986 + 87 


1986 1987 1986 + 87 


0.5/0.5 
1.0/1.0 
1.5/1.5 
2.0/1.5 


3.2 * 3.6 ** 6.4 ** 

3.3 3.5 5.8 
3.2 3.3 5.1 
3.2 • 3.3 5.1 


0.4 ** 
0.2 
0.1 
0.1 


2.8 ** 3.2 ** 
2.3 2.5 
1.8 1.9 
1.7 1.9 


114 ** 649 ** 763 ** 
93 524 617 
78 350 428 
89 378 467 


*No significant differences existed. 

**For these measurements there was a significant linear decrease between the 0.5/0.5 and 1.5/1.5 treatments. 

There was no significant difference between the 1.5/1.5 and the 2.0/1.5 treatments. 



Table 2. The effects of urea application technique on the trunk and shoot growth of Summerland Red 
Mclntosh/Mark trees planted in 1986. 



Trunk circumference (cm) 

Application 

treatment At planting 1986 1987 


Change 
1986 


in trunk circ. (cm) 
1987 1986 + 87 


Shoot 


growth (cm) 


1986 


1987 1986+87 


Dry 3.8 * 4.2 * 
Foliar 3.7 4.3 
Drench 3.5 3.9 


7.1 * 

6.9 

7.4 


0.4 * 

0.6 

0.4 


2.9 * 3.2 * 
2.6 3.2 
3.5 3.9 


117 * 

132 

108 


657 * 774 * 
652 784 
770 878 



*No significant differences existed. 



ammonium nitrate and determine if a smaller dose may be 
appropriate for newly planted trees. 

Nitrogen Application Technique 

The second planting (Summerland Red Mcintosh/ 
Mark) established in 1986 studied the effects of nitrogen 
application technique the year of planting on tree growth. 
In 1986 trees all received 0.25 pound of urea, but it was 
applied either dry to the soil on May 15, in solution as a soil 
drench on May 8, or in foliar applications on May 25 and 
June 8. In 1987 all trees received a soil treatment of 1 
pound of ammonium nitrate. Tree growth was measured 
as in the first planting. Data are reported in Table 2, and 
they showed that application technique did not alter the 
amount of tree growth during the first or second leaf. 

Mulching and Vydate 

In the third planting established in 1986 Gala/M.26 



trees were either mulched with 0.5 bale of hay after 
planting, treated with foliar applications of Vydate 2L^^ (2 
quarts/100 gallons) just after leaf emergence and in mid- 
July, mulched and treated with Vydate, or not treated. 
Mulch was reapplied in 1987. Tree growth was measured 
as in the first planting, and data are reported in Table 3. 
Mulch was included in this planting because it often is 
able to encourage better tree growth, even beyond its weed 
control abilities. In this experiment weed control was 
maintained with herbicides. Vydate was used to control 
nematodes which may reduce growth. Neither mulch nor 
Vydate treatments affected the growth of these trees. 
However, mulch significantly increased the quantity of 
bloom in 1988. It is clear that this response could signifi- 
cantly improve early returns. Additionally, mulched trees 
are less susceptible to extremes in water availability, so 
that over a number of years plantings established with 
mulch would be expected to have better growth even 
though we did not see it in this planting. 



Table 3. The 


effects of hay mulch and Vyd 


ate appli 


cations on the trunk, shoot growth. 


and bloom of Gala/M.26 


trees planted 


in 1986. 




















Trunk circumference (cm) 


Change 


in trunk 


circ. (cm) 


Shoot 


growth (cm) 

























1988 Bloom 




At 


















(clusters/ 


Treatment 


planting 


1986 


1987 


1986 


1987 1986 + 87 


1986 


1987 


1986 + 87 


cmO 


Control 


4.4* 


4.8* 


8.0* 


0.5* 


3.1* 


3.6* 


290 * 


906 


* 11% * 


8.5** 


Mulch 


4.3 


4.8 


8.3 


0.6 


3.5 


4.0 


308 


927 


1235 


20.4 


Control 


4.3* 


4.8* 


8.1* 


0.5* 


3.2* 


3.7* 


282 * 


868 


* 1150 * 


17.0* 


Vydate 


4.3 


4.9 


8.3 


0.5 


3.4 


3.9 


316 


962 


1278 


12.8 


*No significant differences existed. 
















**Significantly different at odds of 99 to 1. 

















Table 4. The effects of various planting treatments on the trunk and shoot growth of Royal Gala/M.26 trees 


planted in 1986. 




















Trunk circumference (cm) 


Change in trunk 


z\TC. (cm) 


Shoot growth (cm) 


Planting 


















treatment At planting 


1986 


1987 


1986 


1987 


1986 + 87 


1986 


1987 1986+87 


Control 


3.8 a* 


4.9 be 


8.5 ab 


1.1 de 


3.6 ab 


4.7 ab 


321 c 


1054 b 1375 b 


Topsoil 


3.8 a 


4.9 be 


9.1a 


1.1 cde 


4.1a 


5.2 a 


321 e 


1509 a 1830 a 


Peat 


3.8 a 


5.4 a 


9.2 a 


1.6 a 


3.8 ab 


5.4 a 


500 a 


1298 ab 1798 a 


Manure 


3.7 a 


5.1b 


8.9 a 


1.4 abc 


3.8 ab 


5.2 a 


399 b 


1184 ab 1583 ab 


Tree planter (TP) 


3.8 a 


4.7 c 


7.9 b 


0.9 e 


3.2 b 


4.1b 


259 c 


998 b 1257 b 


TP + Aliette (2#) 


3.8 a 


4.9 be 


8.4 ab 


1.2bcde 


3.5 ab 


4.6 ab 


294 c 


1137 b 1431 b 


TP + Aliette (4#) 


3.7 a 


5.1b 


8.4 ab 


1.4 ab 


3.4 ab 


4.8 ab 


313 c 


1258 ab 1571 ab 


TP + Ridomil 


3.8 a 


5.0 be 


8.6 ab 


1.2 bed 


3.6 ab 


4.8 ab 


328 c 


1107 b 1435 b 


*Means within columns not followed by the same 


letter are 


significantly different at odds of 19 to 1. 



Planting Techniques, Hole Treatments, and Root 
Fungicides 

The last planting (Royal Gala/M.26) established in 
1986 studied the effects of planting hole treatments, plant- 
ing techniques, and post-plant root fungicides. In this 
experiment half of the trees were planted with a tree 
planter and half were planted into an 2-foot augered hole. 
The trees in the auger holes either were planted with the 
soil that was removed from the hole, good topsoil from 
another site, a mixture of 1:1 peat-to-topsoil, or a mixture 
of 2:1 composted manure-to-topsoil. Trees planted with a 
tree planter were either sprayed in 1986 and 1987 to the 
drip point with Aliette^^ (at 2 pounds/100 gallons or 4 
pounds/100 gallons) late spring, mid-summer, and early 
fall; treated with a soil drench in 1986 and 1987 of 1 quart 
of Ridomil^^ (at 1 quart/100 gallons) late spring, mid- 
summer, and early fall; or were not treated with either root 
fungicide. Tree growth was measured as in the first 
planting, and data are reported in Table 4. 

In 1986 the most prominent effect was caused by the 
addition of peat to the planting hole. Peat-treated trees 
had the largest increase in trunk circumference and the 
most shoot growth. The addition of composted manure 
also improved growth but not to the extent of the peat 
treatment. In 1987 differences in growth rate began to 
dissipate except for the topsoil treatment. Using good 
topsoil in the planting hole did not have much effect the 
first year; however, in 1987 those trees had significantly 
more shoot growth than the controls. At the end of 1987 
the largest trees, in terms of trunk circumference, were 
those planted with good topsoil, those planted with the 
addition of peat, and those planted with the addition of 



manure. Trees planted in an augered hole seemed to grow 
better than those planted with a tree planter; however, the 
differences between the two were not statistically signifi- 
cant. These results suggest that the use of some type of 
planting treatment can significantly improve the growth 
and development of the trees to be planted. However, it 
may be difficult to apply these types of treatments in some 
situations, such as when a tree planter is used. Therefore, 
at times it may be more practical to use surface applica- 
tions of organic material or the growing of cover crops with 
subsequent plowing or tilling under to improve the soil. 
When the soil has been prepared such as this before 
planting the effects probably will last longer than if only an 
augered hole is treated. 

The use of root fungicides had only a small effect on 
tree growth. In 1986 the high level of Aliette and the 
Ridomil treatment resulted in more trunk growth but no 
increase in shoot growth. In 1987 no growth differences 
existed. One could conclude that these root fungicides give 
little benefit; however, at some sites the pressure of root- 
attacking fungi may be much greater than at this site at the 
Horticultural Research Center and the effect may be much 
greater. 

It is clear from the results of these four experiments 
that cultural treatments performed at planting or to newly 
planted trees can have significant effects on tree growth. 
The importance of early tree growth and the establishment 
of a fruiting framework suggests that growers should 
carefully prepare a site before planting, and consider the 
use of some of these treatments during the planting year. 
We shall continue to study improvements of tree develop- 
ment with cultural techniques. 



* * * 



The Effects of Travel Speed, Nozzle 
Arrangement, and Application Volume on 
Pesticide Distribution in Apple Trees 

Daniel R. Cooley 

Department of Plant Pathology, University of Massachusetts 



Spraying recommendations may seem as though they 
are based only on common sense rules of thumb, or worse, 
nothing at all. So it is encouraging when scientific facts are 
generated that support spraying recommendations. 

Dr. Jim Travis and Dr. Turner Sutton, plant patholo- 
gists at Pennsylvania State University and North Carolina 
State University, respectively, recently completed studies 
on spray deposits in apple trees. The usual recommenda- 
tion to direct 2/3 of the sprayer output toward the top 
1 /3 of the tree, and 1 /3 of the output at the bottom 2/3 of 
the tree is based on work done in 1965. Since that time, in 
spite of the significant changes in tree size and pesticide 
formulation, that recommendation has continued to be 
made. Travis and Sutton found that the recommendation 
is still relatively sound, if trees are of medium size (ap- 
proximately 13 ft high X 12 ft in diameter). However, as the 
tree size decreases to 9.5 ft high x 9.5 ft in diameter, a 50:50 
ratio (half directed at the top 1/3 and half directed at the 



bottom 2/3) gives the best deposit throughout the tree, and 
the lowest variability from one part of the tree to another. 
Of course, there are many other factors which affect 
spray deposition. Of those examined in the recent study, 
the following were found to optimize spray deposition: 

1. A tractor speed of 2 mph was found to be better than 1.5 
or 2.5 mph; 

2. A rate of 66 gal/acre was better than 40, 100, or 400 gal/ 
acre; 

3. Well pruned trees were better than moderately to 
poorly pruned trees. 

Adhering to these guidelines could improve spray 
deposition and distribution in fruit tree foliage, making 
pesticide applications more effective and more efficient. It 
is important to note that the tests were made under a 
specific set of conditions, which may or may not have 
relevance to each particular orchard. However, if these 
practices can be tried, they can help control costs. 



:(: * 4: 

Biological Control of Apple Blotch Leafminers 
in Massachusetts Apple Orchards 

Roy G. Van Driesche, Ronald J. Prokopy, and William M. Coli 

Department of Entomology, University of Massachusetts 

T. Bellows 

Department of Entomology, Division of Biological Control, University of California, 

Riverside, CA, 92521 



Introduction 

The apple blotch leafminer (ABLM), Phyllonorycter 
crataegella (Clemens) is a small (1/4 inch) moth in the 
family Gracillariidae that has become a significant pest in 
Massachusetts apple orchards since the mid 1970's. This 
problem has occurred due to the development of resis- 
tance to common orchard cover spray materials, such as 



azinphos-methyl (Guthion™), which formerly suppressed 
populations as a side effect, although there was no con- 
scious effort on the part of the growers to do so. 

Following the first detection of resistance in ABLM 
populations in Massachusetts, resistance spread rapidly 
throughout the region. Densities of mines rose sharply as 
the pest was controlled neither by cover sprays (which no 
longer affected the moth), nor, in commercial orchards, by 



parasites, which were easily killed by orchard cover sprays. 

A broader view shows that this same scenario of 
pesticide-resistant leafminers and pesticide-susceptible 
parasites has led to significant pest problems from a 
number of other Phyllonorycter species on apple or other 
tree fruits in many areas, including P. blancardella (F.) in 
New York, Michigan, and Ontario (Dutcher & Howitt, 
1978; Free et al., 1980; Weires et al., 1980), P. corylifoliella 
(Hubner) in Holland (Van Frankenhuyzen, 1975), P. el- 
maella (Doganlar & Mutuura) in Utah (Barrett & Jor- 
gensen, 1986), and P. ringoniella (Matsumura) in Japan 
(Sekita & Yamada, 1979). This repeated pattern high- 
lights the vulnerability of single-factor chemical controls 
which, once breached by pest resistance, leave pests free to 
multiply unrestrained by natural enemies which typically 
are slower to develop pesticide resistance (if ever) and 
hence cannot attack the pest in the sprayed environment. 

Because high density leafmincr populations can ad- 
versely affect apple crops by increasing drop and reducing 
flower bud formation (Reissig et al., 1982) and because 
Phyllonorycter spp. have a high capacity to develop pesti- 
cide resistance, it is important that orchardists in Massa- 
chusetts broaden control systems immediately to protect 
and encourage the specialist parasites that attack ABLM. 
If this is not done, further resistance in the species likely 
will occur to the specific carbamate and organochlorine 
materials that are currently effective and used against high 
density leafminer populations. 

Major Parasites of ABLM in Massachusetts 

Studies in Massachusetts (Van Driesche & Taub, 
1983), Connecticut (Maier, 1984), New York (Weires et 
al., 1980), and elsewhere have consistently shown that 
Phyllonorycter species attacking apple are themselves ex- 
tensively attacked by several species of parasites in the 
absence of interference from pesticide applications. The 
most important of these in Massachusetts at this time are 
the braconid, Pholetesor omigis (Weed), and the eulophid, 
Sympiesis marylandensis (Girault) (Van Driesche & Taub, 
1983). 

P. omigis is a black species, 1/4 inch long, that attacks 
tissue feeding host larvae, laying its egg inside the body of 
the host larva. The mature parasite larvae exits from the 
host and spins a white cocoon inside the leaf mine. Detec- 
tion of parasitism by P. omigis is easiest in old mines since 
parasite cocoons are readily visible to the naked eye and 
remain present even after the adult parasite has left the 
mine. Parasite cocoons are easily separated from both live 
and emerged moth pupae. 

S. marylandensis, in contrast, is smaller (1/8 inch), 
metallic blue-black in color, and attacks tissue stage larvae. 
Its eggs are laid next to, but outside of, the host larvae and 
are visible with a hand lens. Parasite larvae develop and 
feed outside the host larvae and pupate in the mine, with no 



cocoon. Parasitism by this species can be detected at any 
time because of its position external to the moth larva. In 
addition to killing hosts by parasitization, 5. marylandensis 
adults directly attack and kill other tissue feeding larvae 
which they pierce with their ovipositor and then partially 
consume as a source of protein. Larvae killed in this 
manner appear dried out and shriveled 2md are often 
attached to the mine "skin" at a single point, where the 
parasite formerly fed. 

Other potentially important parasite species, not yet 
found in Massachusetts, include the braconid, Pholetesor 
pedias (Nixon), and the encyrtid, Holcothorax testaceipes, 
both recently introduced to Ontario (Laing & Heraty, 
1981) from New Zealand and Japan, respectively. 

Management Options Available to Growers to 
Promote Biological Control of Apple Blotch 
Leafminer Populations 

The major infiuence on parasite populations in apple 
orchards is the pesticide regime, both in terms of its 
duration and the particular chemicals selected for use. To 
a lesser extent, proximity of wild or abandoned apple trees, 
or wild cherry trees where parasite populations will be 
found attacking various species of leafminers, can also 
infiuence events within commercial apple orchards. 

Pesticide Management . Attempts have been made to 
identify pesticides more toxic to the pest leafminer than to 
their associated parasites (Weires et al., 1982; Van Dries- 
che et al., 1985). While somedegree of selectivity has been 
found (e.g., for oxamyl; Van Driesche et al., 1985), in 
general all materials which provide effective control of 
leafminer adults or larvae also seriously harm parasites. 
Low rates of low-residual materials are the least damaging 
to parasites. Nevertheless, complete elimination of chemi- 
cal controls of leafminers in favor of reliance on parasites 
should be the goal of orchardists trying to establish biologi- 
cal leafminer control systems, as currently available pesti- 
cides for leafminer control are relatively incompatible with 
parasite survival. 

In addition to pesticide applications directly targeted 
against leafminers, cover sprays against other insects also 
represent a major obstacle to parasite effectiveness within 
commercial orchards. While parasitism levels on non- 
sprayed trees are high (often 60% or greater), levels inside 
blocks sprayed for other insects are typically very low (less 
than 5%), with some increase in the third leafminer gen- 
eration in September after cover sprays have ended (Van 
Driesche and Taub, 1983). It thus appears that the most 
effective action growers can take to conserve leafminer 
parasites in commercial orchards is to end regular cover 
sprays as early in the season as possible, lengthening out 
the insecticide-free period in which leafminer parasites 
can increase in numbers. Currently, cover sprays are 



maintained until mid-August or even into September to 
protect fruit against apple maggot flies. A "Second-stage 
IPM" strategy now being tested in Massachusetts may 
offer a means to extend the length of the insecticide-free 
period by terminating regular cover sprays at the end of 
May after the period of plum curculio attack has ended. 
Control of apple maggot fly in July, August, and Septem- 
ber then would be based on intensive trapping using red 
sticky traps developed by Prokopy and removal of wild or 
abandoned apple trees adjacent to the orchards. While 
initial data (1987) show that this system increases numbers 
of predator mites, data are not yet available as to its effect 
on leafminer parasites. Such data, however, will be col- 
lected in future tests beginning in 1988. 

Habitat Management . Abandoned or wild apple 
trees, or wild cherries in forested areas near orchards 
typically have Phyllonorycter spp. Icafmincrs (including 
ABLM) that serve as hosts for P. omigis and 5. marylan- 
dcnsis. Increased parasitism in commercial orchards in 
late summer and fall results from both within-orchard 
build up of the parasites that survived early season pesti- 
cide applications and perhaps from immigration of para- 
sites into orchards from hosts living on unlcndcd trees. 
The relative importance of these two sources is unknown. 
Wild hawthornc, wild apple trees, and abandoned apple 
trees near orchards all serve as sources of apple maggot 
flies that can enter orchards and hence such trees should 
be removed. Various species of native cherries also serve 
as possible breeding sites for ABLM parasites, but are 
likely to be too few in number to do more than "re-seed" 
orchards that have lost their leafminer parasites due to 
extensive pesticide use. The size of mid- to late-season 
leafminer parasite populations in commercial orchards is 
therefore less likely to be determined by the habitat out- 
side the orchard than by the pesticide application history in 
the orchard itself. 

State Actions of Potential Value in Promoting 
Biological Control of the Apple Blotch Leafminer 

Existing native parasites of ABLM, while fairly effec- 
tive, are not necessarily the species with the highest poten- 
tial to suppress leafminer populations. Because of the 
problems that have arisen in various regions with other 
Phyllonorycter species, much is known of the parasites 
attacking a variety of leafminer species. Some species 
seem to have potential to increase the level of control over 
that provided by our native parasites. For example in 
Ontario, the introduced parasite, Pholetesor pedias, has 
produced levels of parasitism 2 1/2 times greater than the 
native Pholetesor omigis (Laing & Heraty, 1987). This 
parasite has been established in Ontario and more recent- 
ly in New York (Weires, personal communication). An- 
other parasite of potential value is the encyrtid, Holcotho- 
rax testaceipes, which is the major parasite attacking P. 



ringoniella in Japan (Sekita & Yamada, 1979). It has 
recently been established in Ontario and is becoming the 
dominant parasite there as well. A recently approved 
Northeast Regional Apple Project has provided funds to 
Dr. Chris Maier of the Connecticut Agricultural Experi- 
ment Station to introduce both of these parasites to New 
England. 

How to Monitor Parasitism Levels in Your 
Orchard 

Leafminer populations can be monitored either by 
counts of adult moths caught on red sticky traps, or by 
counts of mines per leaf for each leafminer generation. 
Thresholds currently in use in Massachusetts for the sec- 
ond system are 0.13 mine/leaf for the first generation and 
1 .00 mine/leaf for the second generation. These levels are 
lower than thresholds currently used in other states to 
account for compounding effects of mites or drought 
stress. The use of 0.13 mine/leaf as a treatment threshold 
is based on the concept that, given the 7 to 8 fold increase 
typical from the first to the second leafminer generations, 
more than 0.13 healthy mines in the first generation will 
result in damaging populations (more than 1.0 mine/leaf) 
in the second generation. This first generation threshold, 
however, should be raised if levels of parasitism are high 
(Figure 1). Parasitism levels can be determined by select- 
ing one hundred old mines at the end of a generation and 
opening them with needle-nose tweezers. Mines then can 
easily be classified into ones in which moths have devel- 
oped, ones in which parasitoids have developed or ones in 
which the larvae were killed by feeding of adult parasites. 
Percentage parasitism can then be calculated as number of 
mines with dead larvae plus the number with parasitized 
larvae or parasite pupae or cast parasite pupal skins 
divided by the total number of leaf mines sampled. Levels 
of parasitism can be taken into consideration only if 
leafminer levels are assessed in the first generation and 
required treatments are then made in the next generation 
against leafminer adults. This strategy currently has the 
drawback that available materials for killing leafminers 
tend to make mite control problems worse. This effect 
becomes increasingly more severe as the season pro- 
gresses, and thus, given existing pesticides, treatments 
made early against first generation leafminer larvae are 
less disruptive to mite population dynamics than treat- 
ments made for second generation leafminer adults. 
Unfortunately, treatments targeted against first genera- 
tion leafminer larvae cannot use thresholds modified by 
levels of parasitism because parasitism occurs late in the 
leafminer larval stage. If the insect growth regulator 
difiubenzuron (Dimilin™) is registered for leafminer 
control, it will be easier to utilize a strategy based on 
assessing first generation mine numbers and levels of 
parasitism at that time and then treating second genera- 



UJ 

> 



o 
o 



en 

UJ 



80 
70 
60 
50 
40 
30 
20 
10 



T 1 I I 



J 1 1 l_ 



-i 1 1- 



-10 10 20 30 40 50 60 70 80 90 



PERCENTAGE PARASITISM 



Figure 1. Treatment thresholds for apple blotch leafminer. 



tion leafminer adults if needed, because diflurbenzuron is References 
not disruptive to biological mite control. 



Converting Front Pesticide Management to 
Biological Control of Apple Leafminers 

Conversion from pesticide management of apple 
leafminers to management based largely on conservation 
of parasites is essential if growers are to reduce pest 
management costs and the threat of ever increasing pesti- 
cide resistance in leafminer populations. This goal can be 
reached only as part of an integrated reduction in orchard 
pesticide use to increase, to the greatest extent possible, 
the insecticide-free period from mid- to late season. 
Recognition of the principal parasite species and the 
ability to tell a leaf mine that produced a parasite from one 
that produced a moth are essential. Sharp tweezers and a 
hand lens are the required tools for this determination. 
Training can be obtained from regional fruit extension 
agents. Regular assessment of proportions of mines para- 
sitized can help growers remain aware of the status of 
leafminer populations in their orchards and can be used to 
modify recommended chemical control thresholds. 



Barrett, B A. and CD. Jorgensen. 1986. Parasitoidsofthe 
western tentiform leafminer, Phyllonorycter elmaella 
(Lepidoptera: Gracillariidae) in Utah apple orchards. 
Environ. Entomol. 15:635-641. 

Dutcher, J.D. and JA. Howitt. 1978. Bionomics and 
control oi Lithocolletis blancardella in Michigan. /. Econ. 
Entomol. 71:736-738. 

Laing, J.E. and J.M. Heraty. 1981. Establishment in 
Canada of the parasite Apanteles pedias Nixon on the 
spotted tentiform leafminer, Phyllonorycter blancardella 
(Fabr.). Environ. Entomol. 10:933-935. 

Laing, J.E. and J.M. Heraty. 1987. Overwintering of 
Phyllonorycter blancardella (Lepidoptera: Gracillariidae) 
and its parasites, Pholetesor omigis and Pholetesor pedias 
(Hymenoptera: Braconidae), in southwestern Ontario. 
Environ. Entomol. 16:1157-1162. 

Maier, C.T. 1984. Abundance and phenology of parasi- 
toids of the spotted tentiforn leafminer, Phyllonorycter 



blancardella (Lepidoptera: Gracillariidae), in Connecti- 
cut. Can. Ent. 116:443-449. 

Free, DJ., Hagley, EA.C. and Simpson, CM. 1980. 
Resistance of the spotted tentiform leafminer, Phyllon- 
orycter blancardella (Lepidoptera: Gracillariidae), to or- 
ganophosphorous insecticides in southern Ontario. Can. 
Entomol. 112:469-474. 

Rcissig, W.H., R.W. Weires, and CO. Forshey. 1982. 
Effects of gracillariid leafminers on apple tree growth and 
production. Environ. Entomol. ll:958-%3. 

Sekita, N. and M. Yamada. 1979. Studies on the popula- 
tion of the apple leafminer Phyllonorycler ringoniella 
Matsumura (Lepidoptera: LithocoUetidae). IIL Some 
analysis of the mortality factors operating upon the popu- 
lation. Appl. Entomol. Zool. 14:137-148. 

Van Driesche, R.G. and G. Taub. 1983. Impact of 
parasitoids on Phyllonorycler leafminers infesting apple in 
Massachusetts, USA. Prot. Ecol. 5:303-317. ^ 



Van Driesche, R.G., J.M. Clark, M.W. Brooks, and FJ. 
Drummond. 1985. Comparative toxicity of orchard insec- 
ticides to the apple blotch leafminer, Phyllonorycler cra- 
taegella (Lepidoptera: Gracillariidae), and its eulophid 
paTisitoid, Sympiesismarylandensis (Hymenoptera: Eulo- 
phidae). /. Econ. Entomol. 78:926-932. 

Van Frankenhuyzen, A. 1975. Phyllonorycler corylifoliella 
(Hubner 1973) (Lep., Gracillariidae). Entomol. Ber., 
Amersterdam, 35: 1. VIIL 

Weires, R.W., D.R. Davis, J.R. Leeper, and W.H. Reissig. 
1980. Distribution and parasitism of gracillariid leafmin- 
ers on apple in the northeast. Ann. Entomol. Soc. Am. 
73:541-546. 

Weires, R.W., J.R. Leeper, W.H. Reissig and S.E. Lienk. 
1982. Toxicity of several insecticides to the spotted tenti- 
form leafminer (Lepidoptera: Gracillariidae) and its "paxdi- 
silc, Apanleles omigis. J. Econ. Entomol. 75:680-684. 



Controlling Spider Mites in Massachusetts 
Apple Orchards Through Conservation 
of Predator Mites 



Roy G. Van Driesche, Ronald J. Prokopy, and William M. Coli 
Department of Entomology, University of Massachusetts 



Introduction 

Spider mites (European red mite, Panonychus ulmi 
(Koch), and two-spotted spider mite, Tetranychus urticae 
Koch) have become increasingly significant pests in apple 
orchards due to destruction of predator mite populations 
and development of resistance to some major milicidcs. 
While spider mites are not direct pests of the fruit itself, the 
cost of their control has increased relative to control costs 
of other pests. Efforts to reduce production costs 
therefore must include less expensive alternatives for 
spider mite control. This article discusses how the strategy 
of predator conservation may be employed by growers to 
reduce their mite control costs. 

The Predators 

In New England the most important mite predator is 
the phytoseiid m'ltc, Amblyseiusfallacis (Garman) (Table 



1). A second species of importance is the stigmaeid mite, 
Zetzellia mail (Ewing). In Western New York, 
Typhlodromus pyri (Scheuten) rather than/l./o/Zacw is the 
major phytoseiid predator and in Pennsylvania and New 
Jersey, the coccincUid Stelhonis punctum (LeConte) is 
important. 5. punctiim is most often seen as a predator 
attacking high density mite populations (15 or more mites/ 
leaO; whereas, A. fallacis does well moderate mite 
densities (4 to 7/leaO. T.pyri andZ. mali are able to persist 
at very low mite levels (under 3/leaO because of their 
abilities to utilize various alternative food sources such as 
rust mites, pollens, and fungi. Predator mite biology for 
, each species must be understood if management practices 
are to be effective. For example, whereas T. pyri spends 
the entire year in apple Uccs,A. fallacis overwinters in the 
orchard groundcover. Management of orchard 
groundcover thus infiuences both A. fallacis survival and 
the timing of its recolonization of apple trees the following 



season. 



Table 1. Major species 


of mite predators on apples in the Northeastern United States. 


Area 


Species 


Family 


New England 


Amblyseius fallacis (Garman) 
Zetzellia malt (Ewing) 


Phytoseiidae 
Stigmaeidae 


New York 


Typhlodromus pyri (Scheuten) 
Zetzellia malt (Ewing) 
Stethorus punctum (LeConte) 


Phytoseiidae 
Stigmaeidae 
Coccinellidae 


Pennsylvania 


Stethonis punctum (LeConte) 


Coccinellidae 


1 



Conservation Methods Available to Growers 

Pcsticidal chemicals, nitrogen, and orchard 
groundcovcrs are the three orchard components that can 
be manipulated to promote biological mite control. 

Pesticide Management . Growers can create an 
orchard environment more 
favorable for predator mite 
survival and reproduction by 1) 
selecting pesticides that are as 
safe as possible to predator 
mites and 2) ending orchard 
cover sprays as early in the 
growing season as possible. 
Relatively safe pesticides that 
may be used without damaging 
greatly predators do exist 
(Table 2). In part, the relative 
safety ofsome materials, such as 
azinphos-methyl (Guthion^^), 
is due to a natural evolution of 
pesticide resistance in predators 
such as A. fallacis, subject over 
many years to the use of these 
pesticides as orchard cover 
sprays. The relative safety of oil 
to predator mites is due to 
selective timing, in that A. 
fallacis is not on the tree at the 
time that early season 
applications are made to kill 
European red mite eggs. All 
classes of pesticides, including 
herbicides, fungicides, and plant 
growth regulators as well as 
insecticides and miticides, 
should be reviewed as to their 
harmfulness to mite predators 



prior to use. For example, both lime sulfur and benomyl 
are very harmful to A. fallacis, but for very different 
reasons. Lime sulfur is directly toxic. Benomyl induces 
sterility in female predator mites (Hislop & Prokopy, 
1981) and thus, when used from June onward, destroys the 
potential for the population to persist and grow. Miticides, 



Table 2. Relative harmfulness of orchard pesticides other than acaricides | 


to predator mites in 


apple."^ 




Very harmful 


Moderately harmful 


Relatively safe 


chlorpyrifos'' 


phosphamidon 


oil" 


methomyl 


karathane 


malathion 


carbaryl 


amitraz 


phosmet 


oxamyl 


difolatan 


azinphos-methyl 


phosalone 


dinocap 


endosulfan 


diazinon 


dikar 


methoxychlor 


dcmeton 




glyodin 


dimethoate 




dodine 


pcrmethrin 




maneb 


fenvalcrate 




thiram 


ammonium sulfate 




dichlone 


paraquat 




captan 


glyphosate 




ferbam 


benomyl" 




simazine 


lime sulfur 




dalapon 

NAA 


^Data from Hislop & Prokopy (1981) and Butkewich & Prokopy (1985) | 


u&ing A. fallacis as test species. 




''At low dosage, this material may be relatively safe. 




"Oil does not affect A. fallacis because this predator overwinters off the | 


tree in the groundcover and hence is not contacted by 


oil applications 


made in the very early periods of the growing season. 




"Harmful because it sterilizes female predator mites. 





although by definition directly toxic to mites, still offer a 
spectrum of safety to predator mites, ranging from 
dormant oil that is relatively safe to A. fallacis, to 
formetanate hydrochloride (Carzol^^) which is extremely 
damaging to predator mites. Miticides in current use are 
arranged in terms of relative safety toA. fallacis, the major 
mite predator in Massachusetts, in Table 3. 

Second-stage IPM, currently being developed in 
Massachusetts apple orchards, provides another approach 
to pesticide management that aids in conserving mite 
predators. Under this management strategy, regular cover 
sprays are used only in the early portion of the growing 
season (to approximately the end of May). After this 
period only fungicide applications are made. Apple 
maggot fly damage is prevented after termination of cover 
sprays by intensive trapping (using red sticky spheres) and 
removal of wild or abandoned apple and hawthornc trees. 
Preliminary data on this strategy from 1987 tests show an 
improvement of predator:prey mite ratios from 1:9 in 
grower-sprayed control blocks to 1:5 in second-stage 1PM 
blocks. At the 1:5 ratio predator mites can be relied on to 
maintain spider mites under commercially acceptable 
control in most cases. 

Nitrogen Management . Apple foliage with elevated 
nitrogen levels is a more nutritious food for spider mites, 
resulting in more rapid development and a larger number 
of eggs laid per female mite (van DcVric & Boersma, 
1970). This more rapid build up of spider mite populations 
makes control by any existing level of predator mites more 
difficult. Nitrogen levels thus should be kept at the lowest 
levels consistent with healthy tree growth. Nitrogen may 
become available to trees either directly, in the form of 



fertilizer applications, or indirectly from nutrients 
released from groundcovers killed by herbicide 
application or plowing. Growers should monitor actual 
nitrogen levels in leaves and adjust their fertilization 
practices accordingly. 

Groundcover Management . Over and above the 
indirect effects of orchard floor vegetation management 
through leaf nitrogen levels, groundcover management 
directly influences predator numbers. Because A. fallacis 
overwinters off the tree, groundcovers can influence the 
numbers of predators that survive, and can affect the 
timing in the following growing season of predator 
movement back into the trees. The timing of predator re- 
entry into trees depends in part on the availability of two- 
spotted spider mites and other food sources in the 
groundcover. The ideal groundcover species and 
management practices are not known, but are currently 
the subject of research in both Massachusetts and New 
York. In addition, herbicides are sometimes used to kill 
strips of orchard floor vegetation. Certain of these (e.g., 
glyphosate, paraquat, and ammonium sulfamate, see 
Table 2) are highly toxic to predator mites. 

Other actions that growers can take to promote 
biological mite control include encouraging development 
of apple rust mite populations. These mites make apple 
leaves less favorable for spider mites and serve as food for 
predator mites when spider mites are scarce. Alternate 
food sources moderate predator mite population declines 
when primary prey species are low in number with the 
result that more predators remain in the orchard to 
suppress spider mite populations when their numbers 
begin to increase. 



Table 3. Impact of orchard 


acaricides on predator mites. 














Overall 




Material 




Trade name 




impact^ 


Comments 


oil 




— 




5 


Use split application (half at 
half inch green and half at tight 
cluster or early pink) 


propargite 




(Omite™) 




4 




fenbutatin-oxide 




(Vendex™) 




4 




clofentezine 




(Apollo™) 




4 




hexythiazox 




(Savey™) 




4 




oxythioquinox 




(Morestan™) 




3 


For pre-bloom use only, do not 
combine with oil 


dicofol 




(Kelthane™) 




2 


Very hard on predators 


formetanate 












hydrochloride 




(Carzol™) 




1 


Very hard on predators 


^Safety index, with 1 


being most harmful and 5 being 


safest 


on A. fallacis. 





10 



In addition, growers whose orchards have few 
predator mites (due to factors such as past pesticide use 
practices) can "re-seed" their orchards by purchasing 
predators, such asA.fallacis, from commercial sources 
and releasing them on orchard trees to induce a more rapid 
increase in predator numbers, which must then be 
conserved by altered (i.e. reduced pesticide) management. 
In some cases such purchased predators may possess 
higher levels of pesticide resistance than is common in 
native predator mite populations. Such resistance will 
promote better predator mite survival and reproduction 
for populations subjected to pesticide use. 

State Programs to Enhance Biological Mite 
Control 

Most of the decisions that influence biological mite 
control in apples are made by growers. Two areas exist 
however where state (or University) programs could 
contribute to this process: introduction to Massachusetts 
of more highly pesticide-resistant strains of existing 
predator mite species and introduction of new species of 
predator mites not currently found in Massachusetts. 
Higher levels of pesticide-resistance than exist in field 
populations have been induced in A. fallacis and other 
species of phytoseiid predator mites. Such a pesticide- 
resistant strain of A. fallacis has been released and 
established in apples in Quebec with good results 
(Bostanian & Coulombe, 1986). 

Existing native species of mite predators in 
Massachusetts {A. fallacis etc.) are not necessarily the 
most effective possible predator species. Some success has 
occurred in establishing exotic predator mites in other 
regions. For example, T.pyri has been moved successfully 
to Austraha for control of European red mite (Thwaite & 
Bower, 1980). Examples listed by McMurlry (1982) of 
species that are of value against spider mites in apples in 
other regions of the world \nc\\\de, Amblyscius potcntillae 
(Garman) from Europe and Typhlodroimis arboreus 
(Chant) from Oregon, among others. Attempts to 
establish exotic mite predators on outdoor crops generally 
have been inhibited by the widespread belief among 
research acarologists that locally existing native species 
likely are to be superior due to better adaptation to the 
local conditions. However, given that apples, European 
red mite and two-spotted spider mites all are recent 
introductions in Massachusetts (i.e. a few hundred years at 
most), there is little reason to hold this view. Successes in 
other areas argue for trials of exotic species to test whether 
or not more effective mite predators might not be 
obtainable. 

Assessing Predator Levels in Your Orchard 

Decisions to apply or not apply miticides are made 



based on evaluations of numbers of prey mites (not 
counting eggs) per leaf in light of numbers of predators 
(either per leaf or per prey mite) and the point in the 
growing season. The simplest assessment system is a fixed 
predatorrprey ratio. For example if on 50 leaves 50 
predators and 500 prey are found, you have a 1:10 
predator: prey ratio, or 10 prey per leaf and only 1 predator 
per leaf. Massachusetts makes miticide recommendations 
based on a threshold than varies with the season (i.e. spray 
if there are 2 to 3 mites/leaf in June, but 3 to 5/leaf in July 
and 5 to 15/lcaf in August). New York recommends 
miticide applications if there are more than 5 prey mites/ 
leaf unless predators are numerous (1 or more per leaf). In 
general a 1:5 predator:prey ratio seems to indicate good 
prospects for biological mite control. A 1 : 10 ratio indicates 
less prospect for control (but still possible). Ratios smaller 
than 1:10 indicate biological mite control is unlikely to 
occur. 

Actually counting all the mites on each of 40 or so 
leaves can be a difficult task. To simplify the process. New 
York has developed a sequential sampling scheme in 
which leaves are picked one after another and then each 
leaf is classified as cither having or lacking spider mites and 
having or lacking predators. A chart with curves then 
allows the sampler to determine if predator:prey ratios are 
such that biocontrol is likely to occur, if miticide 
applications arc needed, or if more leaves should be 
examined (Nyrop, 1987). This scheme has been developed 
for T. pyri in New York. No similar scheme has been 
developed yet (or A. fallacis in Massachusetts. 

In Pennsylvania, a more elaborate decision making 
process in the form of a question and answer "expert 
system" has been developed that growers can use on home 
computers. No similar system exists in Massachusetts. 

Regardless of the exact thresholds used, growers who 
wish to monitor predator:prey ratios in their orchards 
must learn to recognize predator mites as distinct from 
prey mites (i.e. spider mites). A hand lens is sufficient for 
this task and training can be requested from the regional 
fruit extension agents. 

How to Convert From a Pesticide Mite Control 
Program to a Biological Control Program 

Growers who wish to change management strategies 
from chemical to biological mite control should begin by 
requesting an evaluation of their mite control situation 
from an IPM specialist or extension representative. 
Factors to consider include past and current pesticide use 
(both amounts and specific types), orchard floor 
vegetation management, nitrogen management, and 
current spider mite and predator densities. IPM scouts 
can as.sess probable influences of various actions on mite 
populations and recommend specific actions to promote 
mite biological control. Regular monitoring for the first 



11 



season is essential to determine if mites are responding as 
desired, and to determine timing and choice of any 
supplemental mite control treatments that may prove 
necessary. A period of several years may be required to 
convert from an intensive chemical control program to one 
based on conservation of mite predators, as predator 
populations will require time to increase in numbers. This 
process may be shortened by purchasing and releasing 
predator mites into orchards lacking predators after 
predator conservation practices have been established 
(see, for example, Field et al., 1979). 

References 

Bostanian, N.J. and LJ. Couiombe. 1986. An integrated 
pest management program for apple orchards in 
southwestern Quebec. Can. Entomol. 118:1131-1142. 

Butkewich, S.L. and R.J. Prokopy. 1985. Update on the 
relative toxicity of orchard pesticides to the predator mite 
Amblyseius fallacis. Fruit Notes 50:9-10. 

Field, R.P., W.J. Webster and D.S. Morris. 1979. Mass 



rearing Typhlodromus occidentalis Nesbitt (Acarina: 
Phytoseiidae) for release in orchards. /. Aust. ent. Soc. 
18:213-215. 

Hislop, R.G. and RJ. Prokopy. 1981. Integrated 
management of phytophagous mites in Massachusetts 
(U.S A.) apple orchards. 2. Influence of pesticides on the 
predator Amblyseius fallacis (Acarina: Phytoseiidae) 
under laboratory and field conditions. Prot. Ecol. 3:157- 
172. 

McMurtry,JA. 1982. The use ofphytoseiids for biological 
control: progress and future prospects. In: Recent 
Advances in Knowledge of the Phytoseiidae, MA. Hoy (ed), 
Pub. 3284 of the Univ. Cal., 92 pp. 

Thwaite, G. and C. Bower. 1980. Predators spell doom for 
orchard mites. Agric. Gazette ofN. S. W. 91(4):16-19. 

van dc Vrie, M. and A. Bocrsma. 1970. The influence of 
the prcdaccous mite Typhlodromus (A.) potentillae 
(Carman) on the development of/'a/i<?/i>'c/iwjw//m (Koch) 
on apple grown under various nitrogen conditons. 
Entomophaga 15:291-304. 



* * * 



Comparing Costs of Rubigan^"^ and 
Conventional Fungicides 

Daniel R. Cooley 

Department of Plant Pathology, University of Massachusetts 



One of the most appealing features of the ergosterol 
biosynthesis inhibiting fungicides (Si's) is that they offer 
longer periods between applications than do conventional 
fungicides. Rubigan 1 EC^^ at 6 oz/acre, when combined 
with a half-rate of Dithane M45 80W™ (0.75 lbs/ 100 gal), 
has performed well when used at 10 day intervals in tests at 
the Horticultural Research Center, Belchcrtown, MA 
(Table 1). It should be noted that the performance of 
Rubigan at the 4-oz rate plus the half-rate of Dithane is not 
as good, and generally would not be acceptable, at the 10- 
day intervals. After looking at efficacy, we then examined 
the economics of a complete-season Rubigan program. 

At 10-day intervals, 6 Rubigan/Dithane applications 
were used in primary scab season last year (Table 2). At 7- 
day intervals, 9 standard applications would have been 
necessary. Looking at fungicide costs, using retail cost 



estimates, we found that the Rubigan/Dithane program 
was more expensive than a standard program (Tables 2 
and 3). (The standard program used was 1.5 lbs/100 gal in 
all applications, plus 2 applications containing 3/8 lb/100 
gal Cyprex 65W.) 

However, fungicides themselves are only part of the 
costs. Application costs, such as gasoline, equipment wear, 
and labor, must also be considered. Since the Rubigan/ 
Dithane program requires fewer applications, then such 
costs over a season will be lower. Estimates for application 
costs vary: in Massachusetts they are estimated at approxi- 
mately $5.50/acre/application, while in New York they 
are estimated at $16.00/acre/application. When the non- 
fungicide costs were varied, and applied to different types 
of seasons, the following results were obtained (Table 4). 

In a season similar to last season (9 standard sprays vs. 



12 



Table 1. Scab incidence under 10-day Rubigan/Dithane 


programs at two rates, 1987. 


Fungicide & Rate 




Percent scab incidence 




Cluster 




Terminals 


Fruit 


Rubigan lEC 4 oz plus 
Dithane M45 SOW 2.25 lbs 


0.7 a' 




0.3 a 


1.7 a 


Rubigan lEC 6 oz plus 
Dithane M45 80 W 2.25 lbs 


2.9 a 




0.5 a 


4.7 b 


Dithane M45 80 W 2.25 lbs 


13.1 b 




1.5 b 


5.7 b 


Non-sprayed control 


23.6 c 




4.4 c 


23.0 c 


'Means within columns not followed by 
odds of 19:1. 


the same 


letter 


are significantly different at 



Table 2. Comparison 


of actual 10-day SI spray 


applications with a 


theoretical 7-day 


urogram (based on 


Horticultural Research Center data, 1987). 












Mill's scab 










infection period 






Infection period 


Growth stage 


and severety 


Standard 


Rubigan/Dithane 


April 16 - 18 


1/4 to 1/2" 


light 


yes(4/15) 


yes(4/19) 


April 20 - 21 


early TC 


light 


no 


no 


April 25 


TC 


none 


yes(4/25) 


no 


May 2 


late TC 


none 


no 


yes(5/2) 


May 7 - 9 


pink to bloom 


heavy 


yes(5/5) 


ycs(5/12) 


May 16 - 17 


petal fall 


heavy 


yes(5/12) 


no 


May 21 - 22 


late PF, set 


heavy 


yes(5/19) 


yes(5/22) 


May 22 - 23 


late PF, set 


heavy 


no 


no 


May 27 -28 


set 


heavy 


yes(5/26) 


no 


May 30 - 31 


1/4" fruit 


moderate 


no 


no 


June 2 - 3 


1/4" fruit 


heavy 


yes(6/l) 


yes(6/l) 


June 4 - 5 


1/4" fruit 


heavy 


no 


no 


June 12 - 13 


3/4" fruit 


heavy 


yes(6/8) 


yes(6/ll) 


June 13 - 14 


3/4" fruit 


heavy 


yes(6/15) 


no 


Totals 




12 


9 


6 


Cost 






$76.07^ 


$79.40" 


'Dithane M45 80W, 1 


5 lbs/100 gal, 4.5 to 3.6 lbs/A plus 2 applications in combination with Cyprex 65W, 3/ 


8 lb/100 gal., 1.13 to 0.9 lbs/A. 








^Rubigan 1 EC 6 oz/A in combination with Dithane M45 SOW, 0.75 to 0.6 lbs/A. 





13 



Type of season 
(Mills period) 



6 Rubigan/Dithane), if ap- 
plication costs exceed $13.00, 
it would be less expensive to 
apply Rubigan/Dithane than 
a standard treatment. If 
Rubigan is used at the 4 oz 
rate, then application costs 
need to exceed only $6.00 for 
economy. (Note, however, 
that our results with this rate 
may not be commercially ac- 
ceptable.) 

When 6 standard sprays 
are needed versus 4 Ru- 
bigan/Dithane sprays, the 
break-even points for appli- 
cation costs are the same: 
$13.00 at the 6 oz Rubigan 
rate and $6.00 at the 4 oz rate. 
If the season is such that the 
numbers of standard and 
Rubigan/Dithane applica- 
tions are similar, the break- 
even points increase. So, at 7 
standard vs. 6 Rubigan/ 
Dithane applications, appli- 
cation costs need to exceed 
$30.00 (unlikely) for econ- 
omy. 

In fact, it is more likely 
that the Rubigan/Dithane 
applications will save 2 or 3 
sprays, and that the number 

of applications will be 9 vs. 6, or 6 vs. 4, or some combina- 
tion in between. The IPM block at the Horticultural 
Research Center has received an average of 8.5 dosage 
equivalents of fungicide in each of the past 8 years, with a 
range of from 6 to 11 applications. (Last year was the only 
year in which 6 dosage equivalents were used, largely 
because Rubigan was used for the first time in the block.) 
Similarly, Dr. Robin Spitko of New England Fruit Consult- 
ants reports an average of 8.3 dosage equivalents in or- 
chards that they scout, with a range of 6 to 11. In view of 
that, it may be important to calculate application costs, in 



Table 3. Estimates of retail prices used 


in the cost comparisons. 


Material 


Rate per acre^ 


Cost 


Cost per acre 
per application 


Rubigan 1 EC 
Dithane M45 SOW 
Rubigan/Dithane 
Cyprex 65W 


6oz 
4.5 lbs 
6 oz/4.5 lbs 
1.13 lbs 


$1.99/oz 
$1.74/lb 

$2.49/lb 


$11.94 

$7.84 

$15.86 

$2.81 


^Dilute rate, assuming 


300 gal per acre 


required. 





Table 4. Break-even point for non-fungicide application costs under different 
types of seasons and varying numbers of applications. 



Number of Number of 
standard Rubigan/Dithane 
applications applications 



Break-even point' 



6 oz 



4 oz 



Heavy 10 

Moderate - Heavy 9 

Average 6 

Light 4 

Light 4 



7 
6 

4 
3 

4 



$16.00 
$13.00 
$13.00 
$22.00 
none 



$8.00 
$6.00 
$6.00 
$10.00 
none 



Hf application costs are above the figure, the 10-day program is less expen- 
sive; if application costs are below the figure, the standard program is less 
expensive. 



order to determine whether a 10-day program would be 
cost-effective under a given farm's conditions. 

Of course, the convenience of a 10-day program also 
should be considered. And, there may be additional cost 
efficiency when a 10-day schedule allows an insecticide to 
be applied with a fungicide, but a standard program would 
not. A 10 day schedule offers considerable flexibility, and 
does not appear to cost a great deal, if any, more than a 
conventional program, even without considering possible 
convenience and additional savings. 



* * * 



14 



Apple Bruising. I. Evaluating Grading Lines 

William J. Bramlage 

Department of Plant & Soil Sciences, University of Massachusetts 



Bruising is responsible for downgrading large quanti- 
ties of apples and other fruit. A single bruise larger than 5/ 
8 inch in diameter, or several smaller bruises with an 
aggregate area of more than 1/2 inch diameter will elimi- 
nate an apple from the U.S. Extra Fancy grade. Some 
bruising may occur before harvest, but the great majority 
of it occurs during harvest, transport to the packing house, 
grading and packing, transport to the retail outlet, and 
during retail marketing. A great deal of this bruising is 
caused by the harvesting and packing operations, and is 
largely preventable. While any knowledgeable fruit 
grower knows that a ripe apple is easily bruised and can 
identify some obvious sources of bruising, many sources 
are difficult to identify and thus to remedy. 

Personnel at the U.S. Department of Agriculture, 
Agricultural Research Service and at Michigan State 
University have been conducting cooperative research on 
the sources and consequences of apple bruising, and have 
published a series of reports on their findings that are very 
helpful in identifying and correcting sources of bruising. 
This article is the first in a series of articles in Fruit Notes 
on their findings about this extremely important subject. 

Apple packing lines offer many opportunities for 
bruising, but identifying trouble spots is not always easy. In 
a paper presented at the December 15-18, 1987 meeting of 
the American Society of Agricultural Engineers, G. K. 
Brown, C. L. Burton, S. A. Sargent, N. L. Schulte Pason, E. 
J. Timm, and B. E. Marshall addressed this problem. 
Their paper, entitled "Apple Packing Line Damage As- 
sessment," examined bruise, cut, and puncture damage 
incurred by Golden Delicious apples as they moved 
through typical mechanical packing and grading lines. 
Eight different packing lines were tested, representing the 
widely-used equipment and the range of daily capacity of 
commercial packing houses in Michigan. The lines were 
all evaluated twice: mid-September to mid-October 
(freshly harvested apples), and early-January to early- 
February (ripe air-stored fruit). 

Apples were sampled at 4 locations: input to the 
washer, output from the dryer (after waxing), on the sizer, 
and on the packing table. Additional samples were taken 
after bagging. Bruises were all rated according to size 
(diameter): "A" = 1/4 to 1/2 inch; "B" = 1/2 to 3/4 inch; 
"C" = 3/4 to 7/8 inch; "D" = 7/8 to 1 1/4 inch; "E" = 
more than 11/4 inch. 

Sampling at the washer input measured bruising that 
occurred in the flotation tank, the undersize eliminator. 



and the inspection belt. Two-thirds of the apples sustained 
bruises in these operations. Sampling at the dryer meas- 
ured damage from the washer, dewaterer, waxer, and 
dryer. More damage occurred in these operations than 
anywhere else on the line. Sampling on the sizer showed 
damage from the singulator and from transfer to the sizer, 
and this was the second-most source of fruit damage on the 
hne. Sampling at the packing table showed damage that 
occurred from the sizer, and the conveyor, and here the 
least amount of damage occurred. By the time the fruit 
reached the packing table, 99% of them had been bruised 
in the packing line. To evaluate damage in the bagging 
operation, bruise-free fruit were bagged. This step was the 
most damaging of all, bruising 91% of the apples. 

These results are depicted in Figure 1, showing the 
average number of bruises per fruit incurred in each of 
these operations, for each of the 8 packing lines. The data 
shown are for the late test. 

Up to the bagging operation, over 90% of the bruises 
were of the "A" size, less than 1/2 inch in diameter, and 
less than 5% of the fruit were cut or punctured. However, 
during bagging the damage was more severe; 20 to 25% of 
the bruises were 1/2 to 3/4 inch in diameter, and 4 to 5% 
of the fruit were cut or punctured. 

There were few differences in results between the fall 
and winter tests, meaning that ripening had little effect 
when compared with the operations of the packing lines. 
One difference that did exist was that freshly harvested 
fruit were more likely to be cut or punctured than were 
fruit out of storage. 

As you might expect, there were great differences in 
damage among the different packing lines, indicating that 
much of this damage is under the control of the packing 
line operator, and thus is correctable. This was demon- 
strated clearly in that total number of bruises was reduced 
by 50% in the late test, after operators saw the results of the 
early test and began taking corrective actions. 

The authors summarized their assessments of the 
causes of damage as follows. 

Sampling Point A: 

l.RoUing fruit hit steel chains, rollers, plates, and other 
fruit. 

Sampling Point B : 

1. High washer or waxer brush speed resulted in bounc- 
ing and stacking of fruit. 



15 



UJ 

o 
< 

tlJ 



6.5 
6.0 
5.5- 
5.0- 
4.5 
4.0 
:5.5 



a: 

i^ :3.o 

to 

UJ 

^ 2.5^ 

r) 
a: 

"^ 2.0^ 



1.5 

1.0 

0.5-1 

0.0. 



PACXlNOfOUSE 1 




OODE 


i^ 


AVERAGE 


I 1 


8 




r/VA 


3 


^^ 


6 


K^^rt 


4 




7 


^Z^ 


1 


KSSSi 


5 


' — ' 


2 



.L 



SAMPLING POINTS AND DAMAGE INCURRED BETWEEN 
SUCCESSIVE POINTS ON PACKING LINE 



Figure 1. Average number of bruises to Golden Delicious apples incurred between 
points on eight grading lines. A = at input to the washer. B = output from the dryer. 
C = on the sizer. D = on the packing table. E = bagging operation. 



2. Unpadded or poorly padded braces and guides. 
Obstructions in the line. 

3. Mismatched transfers from washer to dewaterer/ 
waxer. 

4. Fruit to fruit contact or impact required for fruit flow. 

5. No partitioning between parallel-flow brushes. 

6. Long resistance time in washer, dewaterer, and waxer 
(low slope angle, fruit contact required for flow). 

7. Fruit hit dryer rollers too fast after leaving the waxer. 
Sampling Point C : 

1. Unpadded plates and rollers. 

2. Dried wax on padded surfaces caused surfaces to be 
rough and hard. 



3. Mistimed singulator to sizer transfer (fruit hit cup or 
bounced). 

4. No timing for transfer of fruit from singulator to sizer. 

5. No transfer plate at singulator-to-sizer transfer. 

6. Fruit-to-fruit impact. 

7. Excess fruit on singulator fell onto hard surfaces in 
recycling line. 

8. Hard cup surfaces on the sizer. 
Sampling Point D : 

1. Excessive belt speeds or sizing cone speeds in sizer. 

2. Excessive drop distance from sizer cup to cross con- 
veyor. 



16 



3. Fruit-to-fruit impact. 

4. No decelerator strips. 

5. No padding in sizer. 

6. Hard surface on sizing cones (metal, rubber). 

7. Excessive recycling on the accumulation tables due to 
fruit volume exceeding packing capacity. 

Sampling Point E : 

1. Fruit-to-fruit contact on the bagger feed-rolls. 

2. Fruit-to-fruit contact as apples drop into the bags. 

3. Excessive vertical drop height from the weight tray to 
the bag. 

4. Excessive fruit size for the bagger. 



5. Dropping bagged fruit onto the conveyor. 

6. Top apples in bags getting hit at the bag closer ma- 
chine. 

7. Bag tumbling at conveyor transfer corners and drops. 

These findings show that many surfaces impacted by 
apples should be padded, that fruit velocity (primarily as 
they roll down transfer ramps) should be slowed, and that 
drop angles (especially in the sizers and baggers) should be 
reduced. Knowing what to look for should help the 
operators of packing lines identify and correct problems, 
thereby substantially reducing fruit bruising during the 
packing operations. 

In subsequent articles based on these Michigan State 
studies, we shall describe other sources of fruit bruising 
and some of its consequences. 



* * * 



An Assessment of CA Storage Operations 
in Massachusetts 



Katrin Kaminsky and William J. Bramlage 

Department of Plant & Soil Sciences, University of Massachusetts 



Development of controlled atmosphere (CA) storage 
in the 1940's and 1950's revolutionized the Mcintosh apple 
industry. This apple has an inherently short life in air 
storage that is made worse by its susceptibility to brown 
core development at temperatures below 37°F. In air 
storage, its quality cannot be maintained beyond 3 or 4 
months. However, in CA, it can be kept at a temperature 
high enough to avoid brown core and, under proper CA 
conditions, retain good quality for up to 8 or 9 months. 
Thus, when done properly, CA can triple the length of the 
marketing season for Mcintosh. 

Current CA recommendations for Mcintosh in Mas- 
sachusetts are 3% O^, 2 to 3% CO^ for the first month and 
then 5% CO^, and 37°F. Some researchers have shown 
that Mcintosh can be stored safely at much less than 3% O^ 
if the COj is also kept very low, but we have never 
succeeded with low Oj storage for our Mcintosh and do 
not recommend low-Oj storage in Massachusetts. The risk 
of injury to the fruit is too high. 

Every year we receive a number of samples of apples 
showing symptoms after storage that strongly indicate that 



storage operation was not correct. These symptoms in- 
clude soft and broken-down apples due to over-ripeness, 
Oj or COj injury due to an incorrect atmosphere compo- 
sition, and core browning or freeze damage due to too low 
a temperature. 

To better understand why these problems occur, and 
to help us in advising CA operators on how to do a better 
job of managing their storages so as to maintain high 
quality of fruit, we conducted a survey of CA operations for 
Mcintosh during the 1986-87 season. A detailed question- 
naire was sent to each of the 28 CA operators licensed by 
the Massachusetts Department of Food and Agriculture, 
and all of them responded to our request. From their 
responses we can construct a reliable profile of CA opera- 
tions for Mcintosh in Massachusetts. This information is 
summarized and evaluated below. 

Survey Results 

Size of Facilities . The 28 CA facilities have a total of 
83 CA rooms with a total capacity of about 590,000 bushels. 



17 



The average operation stored 21,000 bushels, but 50% of 
the operators have a capacity of 15,000 bushels or less. The 
average CA room size was 7,100 bushels, but the capacities 
ranged from 600 to 33,000 bushels per room. Thirteen of 
the CA storages have only 1 or 2 rooms, while 10 have 3 or 
4 rooms, 4 have 5 rooms, and 1 has 7 rooms. All but 4 
operators stored only their own fruit, yet 84% of the fruit 
was destined for the wholesale market. Mcintosh com- 
prised 77% of the stored fruit. These members all show 
clearly that the CA industry in Mcintosh is dominated by 
small storages where the operator stores only his own fruit. 

Room Maintenance Characteristics . About two- 
thirds of the rooms use freon as refrigerant, and the 
remainder use ammonia. Only about two-thirds of the 
operators test the rooms for leaks annually, a serious 
oversight by the remaining operators. For pressure relief 
in the room, 82% use breather bags, 21% use U-tubcs, but 
7% apparently lack a designed relief system. (Percentages 
may exceed 100% because some operators have different 
equipment on different rooms.) In only two-thirds of the 
rooms are floors covered with water before sealing, and 
only 4 operators attempt to measure humidity in the 
rooms. About 75% of the rooms use lime boxes to scrub 
COj from the atmosphere. 

Establishing CA Conditions . During precooling, only 
one-fifth of the operators actually measure fruit tempera- 
tures. Only 39% of the respondents typically fill a room 
within 1 week, and 50% require 1 to 2 weeks for filling. 
(When rooms are opened, 21% typically are emptied in 2 
to 4 weeks, while another 21% require 8 to 12 weeks.) 
Liquid nitrogen was used in 43% of the rooms to generate 
an atmosphere, in most of which 5% O^ was reached within 
3 days. However, one-third of the rooms utilize only fruit 
respiration to generate the atmosphere, which requires 
more than 7 days for 5% O^ to be reached. 

Monitoring the Storage Atmosphere . In about one- 
third of the storages, thermocouples or thermistors are 
used to monitor temperature, and more than 2 locations 
per room are monitored in one fourth of the storages. 
However, nearly 50% of the rooms have only a thermome- 
ter at the door for measuring temperature. Three-fourths 
of the respondents calibrate their temperature-monitoring 
devices annually. 

All storages monitor O^ and CO^ with an Orsat. Only 
8 storages use a pump to draw air from the room to the 
Orsat. Only 7 storages monitor the atmosphere more than 
once per day, and 3 reported monitoring it less than once 
per day. 

Desired storage conditions for Mcintosh varied 
widely. Half of the operators did not state their desired 
temperature, and of those who did, two-thirds set the 
temperature at less than 37°F. For O^ levels, less than half 
of the respondents try to keep the room at 3%. Eleven 
operators try to keep Oj between 3 and 4%, and 5 try to 



maintain Oj at 4 to 5% O^. Sbc operators run rooms at less 
than 3% O^, but no one tries to go below 2%. Half of the 
storage operators try to maintain 5% COj, and nearly half 
try to keep CO^ at less than 5%. 

Atmosphere Variations . Operators were asked to 
identify typical atmosphere fluctuations in "good" rooms 
and in "difficult" rooms. In good rooms, about half 
reported temperature variations of no more than l°Ffrom 
the set point, and about one-third reported that it varied no 
more than 2°F. For Oj, about half reported variation of no 
more than 0.5%, but 6 said that it typically fluctuated more 
than 1% from the desired value. For CO^, responses were 
almost identical to those for Oj. 

One quarter of the operators reported no "difficult" 
rooms. Of those who have such rooms, wide variations in 
Oj or COj were more common than in temperature. When 
asked what condition was most difficult to maintain in their 
storage, half of the operators noted Oj and none noted 
temperature, while one-fourth said there was no real 
difference. When asked what kind of atmosphere injury to 
fruit was most frequent for fruit in their storages, 7 identi- 
fied freezing, 6 identified brown core, 2 identified COj 
injury, and 1 identified low-O^ injury. 

An Evaluation 

This survey clearly show that some of the difficulties 
with fruit quality that CA operators experience when the 
fruit come from storage arise from the sizes of the opera- 
tions. To optimize the benefits from CA, a room should be 
at atmosphere within 7 to 10 days after the first fruit in the 
room were picked. 

Since half of the CA storages in Massachusetts consist 
of only one or two rooms, and half require more than 1 
week to fill a room, it appears that many operators lack the 
volume to fill quickly enough to achieve full benefits of CA. 
How much benefit these operators lose depends on how 
ripe the apples become, how long it actually takes to 
achieve CA conditions, and how well the storage operates. 
Their problems are also compounded by slow pack-out 
rates. Once the CA condition is broken, fruit begin to 
ripen faster, and when 21% of the storages require 8 to 12 
weeks for pack-out, much ripening occurs after breaking 
the CA seal. These operations may benefit substantially 
from division of the rooms, so that they can be both filled 
and emptied faster. 

Once a room is filled, it is critically important that it be 
sealed and brought to atmosphere quickly. One-third of 
the CA rooms still employ only fruit respiration to achieve 
atmosphere pull-down, which takes more than a week. 
Fruit condition is lost during this time — needlessly. 
Liquid nitrogen is easy to use to generate rapidly a low-O^ 
atmosphere, and is especially applicable to small storages. 
No storage should use fruit respiration to generate a CA 



18 



atmosphere with the technology that is readily available 
today. 

We recommend CA conditions of 3% Oj, 5% COj, 
and 37°F for Mcintosh in Massachusetts. Many storages 
are operated under conditions different from these. 

Most operators set temperatures lower than 37°F, 
thus risking brown core development in the fruit. Al- 
though operators indicated that they thought temperature 
was the easiest condition to maintain in CA, low-tempera- 
ture disorders were the most frequently observed prob- 
lems they reported. In part, these problems stem from too 
many operators relying on a single thermometer on the 
door to monitor temperature, but in part they also result 
from deliberately operating at too low a temperature. 

Over half of the storages operate at too high an O^ 
level. The recommended 3% Oj level is a very conservative 
value, intended to allow for some difficulties in maintain- 
ing control. When operators deliberately maintain O^ 
above 3%, they are wasting fruit condition needlessly. The 
same can be said for CO^ levels. About half of the 
operators deliberately maintain CO^ below 5%, often well 
below it. In part this may be due to the practice of placing 
lime in the room. However, when CO^ is less than 5% after 
the first month of storage, fruit condition is being wasted. 

Perhaps the wariness about maintaining recom- 
mended Oj and COj levels arises from distrust of Orsat 
readings. There is always some risk in relying on readings 
from a stationary Orsat. These readings should be 
checked weekly against readings at the door and or read- 
ings with another instrument. We believe that Orsats 
served their purpose in the past, but that it is time to 
replace them with better equipment that is now available. 
Electronic O^ and CO^ monitors offer many advantages 
over the Orsat, and should instill more confidence in the 
readings obtained. 

Some fiuctuations in the storage atmosphere are inevi- 



table, but they need not be large. Large fluctuations carry 
two risks: when Oj is too high or CO^ is too low, fruit 
condition is lost, and when Oj goes too low or CO^ goes too 
high, there may be a risk of fruit injury. It is difficult to 
evaluate how big this problem is in Massachusetts CA 
storages, because our questions and many of the responses 
were somewhat ambiguous. Yet, it is obvious that atmos- 
pheres in many storages fluctuate excessively, and this 
fluctuation too may be responsible for many of the storage 
operators being too conservative in their desired Oj and 
COj levels. 

Excessive fluctuations can arise from many sources. 
One is leakiness of the room, and all rooms should be 
tested and leaks patched annually before filling. Another 
source is infrequent sampling. Atmospheres should be 
monitored once a day at a minimum, but more frequent 
sampling is highly desirable. Another source is improper 
means for adjusting the atmosphere. Letting in too much 
air or using excessive scrubbing rates or times are two 
examples of this problem. 

Much can be done to improve maintenance of the 
storage atmosphere. At the Horticultural Research Cen- 
ter in Belchertown we established an automated system of 
sampling and controlling the storage atmosphere. This 
system is described briefly in an accompanying article. The 
system provides improved atmosphere maintenance, and 
results in conditions that better maintain fruit quality and 
avoid injurious situations. 

This survey of CA operations was of great value 
toward an understanding of the problems that CA opera- 
tors face. We are most grateful to all of our operators for 
providing us with this information. The results of the 
survey illustrate many different sources of fruit losses, and 
hopefully they will be a great help in identifying and 
correcting problems in CA operations that are causing 
serious economic losses to many storage operators. 



* * * 



19 



A User-build System for Automated Monitoring 
and Controlling of CA Apple Storages 

William J. Bramlage 

Department of Plant & Soil Sciences, University of Massachusetts 



The Orsat gas analyzer is used almost exclusively in 
New England to determine the concentration of Oj and 
COj in controlled atmosphere storages. Adjustments of 
the Oj and the COj levels are then performed manually by 
the storage operator. Use of the Orsat is subject to 
considerable operation error. It also is time-consuming, 
resulting in atmosphere sampling no more often than once 
a day in most storages, which in turn can result in signifi- 
cant atmosphere fluctuations, or in problems going unno- 
ticed or uncontrolled for some time. Probably for these 
reasons, CA operators tend to be very conservative in their 
desired O^ and CO^ levels, thus forfeiting some of the 
potential benefits to the fruit from the CA atmosphere. 

To try to improve on CA management in New Eng- 
land we have developed a demonstration system at the 
Horticultural Research Center, Belchertown, that auto- 
mates the CA control procedure. This idea is not new. 
Numerous automatic control systems have been devel- 
oped in other areas, and some excellent systems are 
commercially available. 

Our approach was to try to develop a system at 
minimal cost to the storage operator, since many New 
England storages are small and the operators are short on 
investment capital. It is a system using off-the-shelf com- 
ponents, in which the storage operator is involved from the 
outset in developing a system to meet his or her specific 
conditions and needs. 



Our system was developed by Katrin Kaminsky, as 
part of her M.S. thesis, in cooperation with personnel in the 
Department of Food Engineering who have expertise and 
experience in control systems and computer technology. 
The project was funded by a grant from the Massachusetts 
Society for Promoting Agriculture, with supplemental 
funding from the Massachusetts Agricultural Experiment 
Station. 

The system is designed as a working demonstration of 
automated sampling and control of a CA atmosphere. It is 
in ongoing use at the Horticultural Research Center. To 
provide storage operators with ready access to information 
about the system, a University of Massachusetts Coopera- 
tive Extension Publication has been prepared and is now 
available. The publication provides a step-by-step descrip- 
tion of the system we have developed, and a complete 
listing of supplies and costs that were involved. 

The publication, entitled, "A User-built System for 
Automated Monitoring and Controlling of CA Apple 
Storages," publication C-197, is available from William 
Bramlage or Wesley Autio, Department of Plant & Soil 
Sciences, Bowditch Hall, University of Massachusetts, 
Amherst, MA 01003. We sincerely hope that CA opera- 
tors will obtain a copy and carefully evaluate the applica- 
tion of this system to their operation. We hope that many 
operators will take the appropriate steps to upgrade their 
storage operations with the technology that is now in hand. 



4: :(: 4: 



20 



COOPERATIVE EXTENSION 

U. S. DEPARTMENT OF AGRICULTURE 

UNIVERSITY OF MASSACHUSETTS 

AMHERST. MASSACHUSETTS 01003 0099 



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SERIAL SECTION 
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Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

University of Massachusetts Cooperative Extension, 

United States Department of Agriculture, and Massachusetts Counties Cooperatmg. 

Editors: Wesley R. Autio and William J. Bramlage 



ISSN 0427-6906 




Volume 54, Number 1 
WINTER ISSUE, 1989 

Table of Contents 

Results of the Second Year of 
Second-stage Apple IPM Practices 



Apple Bruising. II. A "Mechanical Apple" 
Measures Fruit Impact During Packing and Transport 

Apple Bruising. III. Impact 
Bruising Leads to Fruit Rotting 



Blueberry Nutrition 
Red Fuji is a Promising New Apple Cultivar 

Apple Rootstocks for the 1990's 

SCIENCES LlBKAtiy 

Apple IPM Program: Delivery and Observations m 1988 



JAN 17 1989 



Fruit Notes 

Publication Information: 

Fruit Notes (ISSN 0427-6906) is published the first day of January, 
April, July, and October by the Department of Plant & Soil Sciences, 
University of Massachusetts. 



The costs of subscriptions to Fruit Notes are $4.00 for United States 
addresses and $6.00 for foreign addresses. Each one-year subscrip- 
tion begins January 1 and ends December 31. Some back issues are 
available for $1.00 (United States addresses) and $1.50 (foreign 
addresses). Payments must be in United States currency and should 
be made to the University of Massachusetts. 



Correspondence should be sent to: 

Fruit Notes 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

University of Massachusetts 

Amherst, MA 01003 



COOPERATIVE EXTENSION POUCY: 

All chemical uses suggested in (his publication are contingent upon continued registration. Thesechemicals should be 
used in accordance with federal and state laws and regulations. Growers are urged to be familiarwith all current state 
regulations. Where trade names are used for identification, no company endorsement or product discrimination is 
intended. The University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied, 
concerning the use of these products. USER ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY 
DAMAGE. 



Issued by the University of Massachusetts Coopera/ive Extension, E. B. MacDougaU, Director, in Jiirtherance of the acts of 
May 8 and June 30, 19} 4. The University of Massachusetts Cooperative Extension offers equal opportunity in programs and 
empicymenL 



Results of the Second Year of Second-stage 
Apple IPM Practices 

Ronald J. Prokopy and Susan A. Johnson 
Department of Entomology, University of Massachusetts 



In a previous issue ofFniil Notes [53(2) :8- 11], we re- 
ported on results in 1987 from the first year of our second- 
stage IPM program in commercial orchards. Second- 
stage IPM employs behavioral, ecological, and biological 
approaches to pest management as a substitute for all 
insecticide and miticide treatments after the last spray 
against plum curculio in early June. The intent of second- 
stage practices is not only to provide an environmentally 
safe, cost-effective approach to controlling summer pests 
that directly attack apple fruit (apple maggot, codling 
moth, summer leafrollcrs) but also to alleviate insecticide 
toxicity to beneficial predators/parasites of important fo- 
liar pests such as mites, aphids, and Icafminers. Allowing 
more natural enemies of foliar pests to flourish reduces the 
need for pesticide treatment against foliar pests and 
thereby lessens the rate (currently very high) at which 
several of these pests are developing resistance to pesti- 
cides. To emphasize further this latter goal, a major facet 
of second-stage IPM is use during April, May, and early 
June of pesticides least likely to be harmful to beneficial 
predators and parasites. 

In the 1987 second-stage IPM tests, we compared 3 
types of non-pesticidal approaches to intercepting apple 
maggot flies before files penetrated the orchard interior. 
These approaches were: (1) placing synthetic apple odor- 
baited sticky red sphere traps every 10 yards in the woods 
immediately surrounding a block of apple trees; (2) plac- 
ing such spheres every 10 yards on perimeter apple trees 
themselves; and (3) spraying perimeter (border row) apple 
trees every 3 weeks from late June through August. In all 
cases, abandoned apple trees within 100 yards of the or- 
chard block perimeter were removed to preclude immi- 
gration of codling moths and summer leafrollcrs. 

In 1988, we repeated the second and third approaches 
in the same blocks as in 1987. The first approach (placing 
spheres in woods) failed to control apple maggot flies to an 
acceptable level. It was replaced in a different set of blocks 
by a treatment that received border row sprays every 3 
weeks from late June onward and that also received 
releases of mite predators into the block interior. Each of 
the 3 approaches used in 1988 was carried out on 6 test 
blocks averaging 2 to 4 acres. Each test block was matched 
with a nearby block of comparable size that received a 
normal amount of spraying during June, July, and August. 



Apple Maggot Ffy Interception Traps on 
Perimeter Trees 

In 1988 we doubled the density of odor-baited sticky 
red sphere traps in perimeter apple trees from 1 trap every 
10 yards to 1 trap every 5 yards. Results (Table 1) show that 
average apple maggot fly captures per block in 1988 were 
about 50% greater than captures in 1987 (compare 3201 in 
1988 with 2054 in 1987). Non-baited sticky red monitoring 
spheres were placed in the interior of each test block and 
grower-sprayed block to provide an estimate of maggot fly 
populations in the block interior. In 1987, 40% more 
maggot flies were caught on monitoring traps in test blocks 
than in grower-sprayed blocks. In 1988, only 11% more 
were caught in the test blocks than in the grower-sprayed 
blocks, reflecting the greater effectiveness of the higher 
density of interception traps in 1988. This greater effec- 
tiveness is also borne out by the low amount of maggot 
injury to fruit in 1988 (0.5% in test blocks vs. 0.2% in 
grower-sprayed blocks). In sum, the higher density of 
interception traps in 1988 did a very good job of preventing 
apple maggot flies from penetrating the block interior. 

Fruit injury by all other pests active after mid-June 
(codling moth, red-banded leafroller, other leafrollcrs, 
scale insects) was essentially the same (no greater than 
0.2%) in test and grower-sprayed blocks in both 1987 and 
1988. This result demonstrates the effectiveness of remov- 
ing apple trees within 100 yards of the orchard perimeter 
as a method of preventing movement of codling moths and 
summer leafrollcrs into orchards (apple maggot flies move 
over much longer distances and are little affected by the 
tree removal method). 

In both 1987 and 1988, total Amblyseius fallacis and 
yellow mite predators were about double in frequency in 
the test blocks compared with the grower-sprayed blocks. 
In 1988, pest mites in the test blocks were effectively held 
in check by predatory mites despite no use of miticide 
other than pre-bloom oil. In the grower-sprayed blocks, 
where miticide was usually used in addition to oil, there 
was a much less favorable pest-to-predator mite ratio. A 
similar pattern held true for aphid predators in 1988: 
nearly double the frequency in the test blocks. Together, 
the results point out the predator-fostering value of com- 
plete elimination of insecticide and miticide use after the 



Table 1. Effects from using AMF interception traps on perimeter trees. 



Avg. no. AMF/block Avg. % fruit injury 

by insect pests active 

Inter- Interior after mid-June^* 

ception monitoring 

traps traps AMF CM RBLR Other 



Year Block No. 



1987 Trapped 6 2054 123 

Grower- 
sprayed 6 — 84 



1.4 0.0 0.1 0.0 
0.5 0.0 0.1 0.1 



1988 Trapped 6 3201 117 0.5 0.0 0.1 0.0 

Grower- 
sprayed 6 — 105 0.2 0.0 0.2 0.0 

Avg. % leaves (or terminals) infested/block"'* 



Ratio of 
pest to 
ERM predatory 

TSM AF YM mites WAA WAL PL LM GAAGAAP 



1987 Trapped 6 20 4.0 3.2 2.8:1 2 9 17 10 - 
Grower- 
sprayed 6 13 1.5 2.3 3.4:1 2 5 10 14 - 

1988 Trapped 6 12 1.3 1.2 4.7:1 3 27 3 11 14 6.7 
Grower- 
sprayed 6 11 1.1 0.1 9.3:1 4 18 2 11 16 3.7 

"^500 on-tree fruit/block sampled during July, August, and September. 

''AMF = apple maggot fly, CM = codling moth, RBLR = redbanded leaf roller, ERM 

= European red mites, TSM = two spotted mites, AF = Amblyseius fallacis, YM = 

predatory yellow mites, WAA = woolly apple aphid, WAL= white apple ieafhopper, 

PL= potato Ieafhopper, LM= leafminer, GAA= green apple aphid, GAAP= green 

apple aphid predators: cecidomyiids and syrphids. 

"400 leaves (or terminals) sampled/block during July, August, and September. 



last curculio spray in early June. 

Woolly aphid and leafminer populations were similar 
in abundance (both low) in test and grower-sprayed blocks 
in both 1987 and 1988. However, both white apple Ieafhop- 
per and potato Ieafhopper populations were greater in the 
test blocks than the grower-sprayed blocks each year. This 
result causes us concern. It indicates we must consider ap- 
plying pesticides specifically against Ieafhopper nymphs in 
test blocks in early- or mid-June. 

We are most encouraged by the results of using apple 
maggot Oy traps on perimeter apple trees. No grower will 
want to hang hundreds of sticky spheres around his or- 



chard each year and clean the spheres of maggot flies ev- 
ery month or so. We have in mind a substitute plan 
whereby a grower might purchase several hundred larger 
spheres (5 to 6 inches or so in diameter) which could be 
more attractive than the current 3-inch spheres. These 
larger spheres could be hung in a permanent position on 
perimeter trees for perhaps 10 years. Only tree pruning 
would necessitate repositioning. In July, each sphere 
would be sprayed with or dipped in a solution containing a 
long-residual pesticide, a feeding stimulant for arriving 
maggot flies, and an agent that would greatly lengthen 
pesticide residual activity. Odor attractants would be 



affixed on a nearby twig. Under this plan, there would be 
no sticky and there would be minimal handling of the 
spheres. We are trying to obtain grant funds to pursue this 
idea. 

Bonier Row Sprees Without Predator Releases 

As in 1987, test blocks in 1988 received a spray of 



Guthion™ or Imidan™ applied only to perimeter apple 
trees every 3 weeks from mid-June through August. The 
interior of the block remained free of insecticide or miti- 
cide during this time. 

As shown m Table 2, in both 1987 and 1988, there was 
little fruit mjury caused by apple maggots, codling moths, 
summer leafrollers, or other insects active after mid-June 
in either border-row-sprayed blocks or the fully-sprayed 



Table 2. Effects of applying border row sprays without mite predator releases in apple 
orchard blocks. 













Avg. % fru 


it injury 










Avg. no. AMF 




by insect 


pests 










on interior 
monitoring 


active after m 


id-June^'' 














Year 


Block 


No. 


traps 


AMF 


CM 


RBLR 


Other 


1987 


Brd-row- 
















sprayed 


6 


104 


0.6 





0.1 


0.2 




Fully- 
















sprayed 


6 


63 


0.8 





0.1 


0.1 


1988 


Brd-row- 
















sprayed 


6 


101 


0.3 





0.1 







Fully- 
















sprayed 


6 


53 


0.2 












Avg. % leaves (or terminals) infested/block'''* 

Ratio of 
pest to 
ERM predatory 

TSM AF YM mites WAA WAL PL LM GAA GAAP 



1987 Brd-row- 

sprayed 6 24 1.2 0.1 19:1 
Fully- 
sprayed 6 16 0.3 48:1 

1988 Brd-row- 

sprayed 5* 12 0.1 0.1 61:1 
Fully- 
sprayed 5 9 0.5 0.1 16:1 



5 





9 


5 


- 


- 


5 


1 


10 


4 


- 


- 


5 


8 


2 


4 


31 


10.7 


5 


6 


2 


6 


23 


8.2 



^500 on-tree fruit/block sampled during July, August, and September. 

''AMF = apple maggot fly, CM = codling moth, RBLR = redbanded leaf roller, ERM 

= European red mites, TSM = two spotted mites, AF = Amblyseius fallacis, YM = 

predatory yellow mites, WAA = woolly apple aphid, WAL= white apple leafhopper, 

PL= potato leafhopper, LM= leafminer, GAA= green apple aphid, GAAP= green 

apple aphid predators: cecidomyiids and syrphids. 

"400 leaves (or terminals) sampled/block during July, August, and September. 

"Owing to a mistake on our part, data on foliar pests in one orchard had to be omitted. 



blocks. This result demonstrates the effectiveness of bor- 
der row sprays in preventing penetration of these fruit-in- 
juring pests into the block interior. 

Unfortunately, mite predators were low in frequency 
in border-row-sprayed blocks in 1988, as they were in 1987. 
Indeed, in neither year in neither type of block was the 



ratio of leaves with predators to leaves with pest mites 
better than 1 to 15. This result suggests a very low proba- 
bility of achieving effective biological control via buildup of 
predatory mites in border-row-sprayed blocks (assuming 
the 6 blocks in which our tests were conducted are repre- 
sentative). From recent work in our department on the in- 



Table 3. Effects from using border row sprays with mite predators releases. 



Year Block No. 



Avg. no. AMF 

on interior 

monitoring 

traps 



Avg. % fruit injury 

by insect pests 

active after mid-June'* 

AMF CM RBLR Other 



1988 Brd-row- 

sprayed 6 
Fully- 
sprayed 6 



135 0.4 0.1 

104 0.2 0.1 

Avg. % leaves (or terminals) infested/block''' 

Ratio of 
pest to 
ERM predatory 

TSM AF YM mites WAA WAL PL LM GAA GAAP 



1988 Brd-row- 












sprayed 6 25 2.2 


0.6 9.0:1 


4 


20 3 


23 9 


3.0 


Fully- 












sprayed 6 20 2.5 


1.6 4.9:1 


4 


20 2 


21 6 


1.8 








Avg. % leaves/ 






Avg. no. 




orchard with 




Tree predators released 


trees 










sampled under these trees 


per orchard 


ERM&TSM 


AF 


YM 


July Yes 


14 




32 


5.5 


0.3 


No 


14 




35 


3.1 


0.2 


August Yes 


14 




19 


4.5 


1.2 


No 


14 




18 


3.1 


0.8 


September Yes 


14 




7 


1.4 


0.3 


No 


14 




9 


1.1 


0.6 



^500 on-tree fruit/block sampled during July, August, and September. 
>'AMF = apple maggot fly, CM = codling moth, RBLR = redbanded leaf roller, ERM = 
European red mites, TSM = two spotted mites, AF = Amblyseius fallacis, YM = predatory 
yellow mites, WAA = woolly apple aphid, WAL= white apple leafhopper, PL= potato 
leafhopper, LM= leafminer, GAA= green apple aphid, GAAP= green apple aphid preda- 
tors: cecidomyiids and syrphids. 
"400 leaves (or terminals) sampled/block during July, August, and September. 



fluence of ground cover and orchard border area compo- 
sition on mite predator abundance, it appears that a sub- 
stantial number of predatory mites may be wind-blown 
into orchards from plants surrounding the orchard. Possi- 
bly such predators are being killed as they contact the 
sprayed border row apple trees. Further work is planned 
to evaluate this possibility. 

All other foliage-injuring pests (woolly aphids, leaf- 
hoppers, leafminers) were fairly low in abundance in both 
1987 and 1988 in both border-row sprayed blocks and fully- 
sprayed blocks. 

In sum, we are pleased with the results of the border- 
row spray program in virtually every respect except the 
failure of predatory mites to build to effective numbers. 

Border Row Sprees With Predator Releases 

In 1988 6 bordcr-row-sprayed blocks and 6 fully- 
sprayed blocks were established in which Amblyseiusfalla- 
cis mite predators were released at the rate of 500 to 1000 
predator eggs, nymphs, or adults under each of 6 to 7 trees 
per block (every 4th tree of the block interior) in July. 

As in the border-row-sprayed blocks without mite 
predator releases, there was little difference between 
border-row sprayed and fully-sprayed blocks in the 
amount of fruit injury by apple maggots, codling moths, or 
summer leafrollers or in populations of woolly aphids, 
leafhoppers, or leafminers (Table 3). 

Of prime interest is the result of the mite predator re- 
leases. Amblyseius fallacis were about equally abundant in 
both the border-row-sprayed and the fully-sprayed blocks 
and were far more abundant in both than in comparable 
blocks (Table 2) where no predators were released. The 
released predators had genotypes largely resistant to 
Guthion and Imidan. This situation may explain the much 
greater abundance of this species in the blocks where they 
were released than in border-row-sprayed and fully- 
sprayed blocks where they were not released. These 
results are encouraging in terms of released predator sur- 
vival during summer in sprayed blocks. We collected data 
in each block on the abundance of pest mites and Ambly- 
seius fallacis on trees where the latter were released vs. im- 
mediately adjacent trees where they were not released. 



These data (Table 3) suggest that the numbers of released 
predators were too few to have affected populations of pest 
mites on the trees and that released predators were rather 
slow to move away from the trees under which they were 
released. This result suggests that in the future, much 
greater numbers of predator mites should be released on 
a greater proportion of trees in the orchard if such releases 
are to provide meaningful biological control of mites. 

Conclusion 

In conclusion, we are highly encouraged by most of the 
results of these past 2 years of second-stage IPM experi- 
mentation. We have a few "bugs" to iron out to render the 
second-stage approach more cost-effective and labor- 
appealing (especially development of a system to replace 
sticky as a method of killing apple maggot flies that arrive 
on spheres). Presently, we see 2 alternative routes to 
achieving potential second-stage IPM success on a practi- 
cal level: (1) no insecticide or miticide used after early 
June, employing baited, pesticide-treated, non-sticky 
spheres around the orchard perimeter to intercept and kill 
apple maggot flies, removing all apple trees within 100 
yards or so of the orchard perimeter, and allowing mite and 
aphid predators to immigrate into and build up in such 
blocks in a pesticide-free atmosphere; or (2) using border 
row sprays as a substitute for employing maggot fly spheres 
and releasing very large numbers of pesticide-resistant 
mite predators (possibly on an annual basis) on a high pro- 
portion of trees. 

Acknowledgements 

We thank the Massachusetts Society for the Promo- 
tion of Agriculture, the USDA Israel Binational Agricul- 
tural Research and Development Fund (BARD) under 
grant US-807-84, and the Northeast Regional Project on 
Integrated Management of Apple Pests (NE-156) for sup- 
porting our work on second-stage apple IPM. Special 
thanks to Betsy Frederick, Esther Ruiz, Phuong Nguyen, 
and Joseph Shepherd, who worked on the 1988 studies. 
Bill Coli, Kathleen Leahy, and Bill Pyne also participated 
in this program. 



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Apple Bruising. II. A "Mechanical Apple" 
Measures Fruit Impact During Packing 
and Transport 

William J, Bramlage 

Department of Plant & Soil Sciences, University of Massachusetts 



A series of recent reports from Michigan State Uni- 
versity describe results of an intense study of causes of 
apple bruising. This research was cooperative between 
personnel of the U.S. Dept. of Agriculture, Agriculture 
Research Service, and the Agricultural Engineering De- 
partment at Michigan State University. In the previous 
article [Fruit Notes 53(4):15-17], we summarized their 
study of bruising of Golden Delicious apples on commer- 
cial grading and packing lines. Here we shall describe a 
companion study of this situation that gives new insight 
into the problems. 

This study was reported in a paper entitled, "Bruising 
Impact Data Acquisition and Analysis in Apple Packing 
and Handling Systems, Utilizing the Instrument Sphere 
(IS)." The paper was presented to the American Society 
of Agricultural Engineers on June 26-29, 1988, by B. R. 
Tennes, H. R. 2Lapp, D. E. Marshall, and P. R. Armstrong. 



The "Instrument Sphere" used in this study is an 
ingenious device designed to simulate an apple and to 
record impacts it experiences as it passes through typical 
commercial operations. It is the size of an apple and is a 
battery-powered computer that senses impacts and rec- 
ords them over times. 

This device was passed 3 times through 5 different 
packing lines along with the apples being graded on those 
lines. Results are summarized in Figure 1, in which 
maximum acceleration on any run is shown at 19 positions 
on a generic packing Une. 

As acceleration increases above about 50 g's, the risk 
of apple bruising increases. In Figure 1 it can be seen that 
high acceleration rates (rates of impact) occurred at many 
points, especially from the initial water dumping through 
the singulator after waxing, and in the automatic bagging 
operation. These results generally substantiate the visually 



^tti^ 




*^^ 



M-Q 



1. WATER DUMPER = 67 g's 

2. SUBMERSION TANK = 58 g's 

3. UNDERSIZE ELIMINATOR = 73 g's 

4. INSPECTION ROLLERS = 68 g's 

5. WASHER/WAXER = 73 g's 

6. DRYER TUNNEL = 130 g's 

7. SINGULATOR = 54 g's 

8. SIZER DROPOUT = 40 g's 

9. TWO WAY CONVEYOR = 22 g's 
lO.BAGGER AUGERS = 51 g's 



< 1 J 



1 1. WEIGH PANS = 48 g's 

12. CONVEYOR TRANSFER = 29 g's 

13. BAG CLOSER MECH. = 34 g's 

14. CONVEYOR = 43 G 

15. TRAY PACKS -25 g's 

16. AUTOMATIC BAGGER = 120 g's 

17. JUMBO PACK =34 g's 

18. PACKING TABLE = 14 g's 

19. BOX ONTO PALLET 

20. PUT INTO BOX - 58 e's 




Figure 1. A schematic drawing of a generic apple packing line, with points of fruit transfer nimibered 
consecutively from input to the water dumper (1) to putting bags into cartons (20). The maximum acceleration 
(g's) of the Instrument sphere is shown at each transfer point during 3 runs on each of 5 different packing lines. 



determined bruising of Golden Delicious apples during 
grading and packing that we described earlier. 

The bagging operation is a point of special concern, 
since it causes so much impact bruising. The high impacts 
(Figure 1) resulted from bags being dropped onto a con- 
veyor in front of the closing machine, the snapping action 
of the bag-dosing mechanism, the transfer points on the 
conveyors leading, and the hand placing of bags into 
shipping cartons. 

Much of this impact bruising during bagging can be 
eliminated. The authors clearly showed this when they 
placed a piece of shag carpet (facing up) between a 
conveyor belt, onto which the bagged apples fell, and its 
steel backing. The Instrument Sphere was dropped differ- 
ent distances onto the belt, with and without the carpet 
backing, and the padding reduced impact of the instrument 
by nearly 75%. 

Instrument Spheres were also used in a transportation 
study. They were placed in the top tray of a tray-pack 
carton, and into 3-lb. bags in a carton. The cartons were 



transported from the packing house to a distribution 
center, and then to a retailer, by a commercial semi-trailer. 
As the trailer peissed over bridges under repair, impacts 
were 3-times greater (54 vs. 17 g's) in the trays than in the 
bags. Apparently, the tight fit in the bags provides protec- 
tion to the fruit during rough transit. Note, however, that 
velocities of these impacts during transport were much 
lower than many of those experienced by apples on the 
grading line (Figure 1). 

The Instrument Sphere developed by these research- 
ers appears to have much value in assessing the sources of 
impact bruising on harvested fruit. This particular study 
re-emphasizes the high potential for bruising apples dur- 
ing the mechanical grading and packing processes, and the 
fact that much of this bruising need not occur. We urge 
readers to review the causes of fruit damaged outlined in 
the previous article evaluate their own packing lines for 
sources of impact bruising, and take corrective actions. 
Bruising is preventable . 



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Apple Bruising. III. Impact Bruising 
Leads to Fruit Rotting 



William J. Bramlage 

Department of Plant & Soil Sciences, University of Massachusetts 



In previous articles [Fruit Notes 53(4):15-17 and this 
issue pp. 6-7], we have examined findings on sources of 
bruising to apples from studies conducted at Michigan 
State University. Here, we shall use their findings to show 

a consequence of this bruising fruit rotting after 

packaging. 

This study was reported by C. L. Burton, Nancy L. 
Schulte Pason, G. K. Brown, and E. J. Timm in a paper 
entitled, "The Effect of Impact Bruising on Apples and 
Subsequent Decay Development," presented to the 
American Society of Agricultural Engineers on December 
15-18, 1987. The authors are researchers in the Agricul- 
tural Engineering Department and the U.S. Department 
of Agriculture, Agricultural Research Service, at Michigan 
State University, East Lansing. 

Blue mold, caused by Penicillium expansum Lk. ex 
Thorn, is responsible for 80 to 95% of the rotting of apples 
that is seen in commercial markets in the U.S. Contami- 
nation with spores of this fungus can occur in the orchard, 



but most of it probably arises in the packing house, espe- 
cially in water dumps and on grading and packing equip- 
ment. Fruit contaminated during these operations may rot 
quickly if the spores are able to penetrate the fruit surface. 
Earlier studies showed that bruises can allow this penetra- 
tion even though the skin is not broken. The study 
reported here was conducted to see how blue mold rotting 
related to impact bruising on apples. The authors con- 
ducted a series of laboratory tests using Mcintosh, Deli- 
cious, and Golden Delicious apples that were bruised on 
surfaces contaminated with blue mold spores. 

Fruit were carefully picked and handled so as to 
minimize pre-storage injury, stored at 34°F for 0, 2, or 4 
months, and warmed to room temperature before bruis- 
ing. They were bruised by being dropped onto a steel plate 
from different heights, which caused impact bruising of 
different severities. The surface of the steel plate was 
covered with blue mold spores to inoculate fruit as they 
impacted on it. Following bruising, the apples were kept in 



Table 1 
bruise 


. Effects 
diameter 


f drop height OB 
on Mcintosh, 


I average 
Golden 


Delicious, and Delicious apples after 0, 2, 
or 4 months of storage at 34°F. 


Drop 

height 

(cm) 


Average 


bruise diameter (mm) 


months 


in storage 





2 


4 


Avg. 


5 


16 


18 


17 


17 


10 


21 


21 


20 


21 


20 


26 


21 


26 


24 


30 


29 


28 


27 


28 


40 


31 


32 


30 


31 


50 


30 


31 


32 


31 


75 


38 


35 


36 


36 


100 


40 


39 


39 


39 


Avg. 


29 


28 


28 





moist plastic containers at 75°F for 5 to 7 days and then 
inspected for rots. 

Increasing drop height increased the average size of 
impact bruises (Table 1). However, bruising was not 
increased by storage time, even though the apples softened 
during storage. Also, cultivar did not greatly influence 
bruise size from a fall of a given height, so the data in Table 
1 are the average values for the 3 cultivars. 

Bruising greatly affected the amount of rotting that 
occurred on these apples, as shown in Figure 1. Bruising 
at harvest (0 months of storage) resulted in very little rot, 
regju^dless of bruise size or cultivar. However, after 2 or 4 
months of storage, bruising led to much rotting, and the 
amount was greater for the apples stored for a longer time 
before bruising. 

Rotting increased as drop height (and bruise size. 
Table 1) increased. A given drop height caused much 
more rotting of Golden Delicious than of the other culti- 
vars, and more on Mcintosh than on Red Delicious, even 
though bruise size from a fall of a given height was about 
the same for all 3 cultivars. 

Since damage to the fruit from a given impact did not 
increase with storage time, but subsequent rotting in- 
creased greatly (Figure 1), the difference must be due to 
ripening changes inside the fruit. It is well known that as 




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60- 
40- 
20 









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*-* Red Delicious 



l y iiii yi ri t ^i ^i iiiyi i " i ''iy I t-i i ) i T i i [ Tiffin [ i "i i *]" ? t-i r ) i 
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Impact drop height (cm) 



Figure 1. Percent blue mold rotting that developed on 3 cultivars of apples dropped different heights onto a con- 
tammated metal plate after 0, 2, or 4 months of storage at 34°F. After bruising, the apples were kept in a moist 
environment for 5 to 7 days at 75°F. 



they ripen, fruit lose their ability to fight-off invading 
pathogens. Bruising, then, must in some way help the 
fungus enter the fruit, and then advancing ripeness allows 
that fungus to more easily rot the apples. Figure 1 shows 
dramatically how the consequences of bruising worsen as 
the bruising occurs on progressively riper fruit. 

In earlier articles [Fruit Notes 53(4):15-17 and this 
issue pp. 6-7], results of packing-line studies of bruising 
were reported. In the study reported here, the authors 
projected the amount of rot that likely would result from 
the bruising incurred by Golden Delicious apples passing 
through commercial packing lines. 

They conclude that bruising of ripe apples on a con- 
taminated packing line (and they all are contaminated) 
would directly lead to 4 to 8% of the tray-packed apples 
rotting within 5 days at 75°F, and that less ripe apples and 



cultivars other than Golden Delicious probably would not 
rot as badly. However, the projections of the authors show 
what can happen and may help explain why some lots of 
apples are rejected because of excessive rotting. Clearly, 
bruising during the grading and packing operations can 
lead to substantial rotting as well as to the direct quality 
loss caused by appearance of the bruises themselves. 

In their earlier studies [Fruit Notes 53(4):15-17 and 
this issue pp. 6-7], the authors showed that much of this 
bruising is preventable, and they described what packing- 
line operators should be looking for, and gave some 
suggestions for alleviating the problem. 

The results described here also re-emphasize the 
importance of practices to reduce build-up of fungal 
spores on and around fruit. A recent article [Fruit Notes 
53(3):15-16] examined this problem and offered sugges- 
tions for controlling apple rotting. 



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Blueberry Nutrition 

Dominic A. Marini 

University of Massachusetts Cooperative Extension, Hanson, MA 



For high yields, blueberry bushes must be vigorous, 
making at least 12 to 18 inches of new growth per year. The 
most productive shoots are those with 15 to 20 leaves. Low 
vigor can be the result of improper or no pruning, dry or 
wet soil conditions, incorrect soil pH, or lack of nutrients. 

Pruning must be done annually in late winter or early 
spring. Mulching with sawdust or wood chips is ideal for 
conserving soil moisture and preventing drought stress. 
Many growers, particularly on light, sandy soils, are using 
trickle irrigation to supply moisture during drought peri- 
ods. Wet soil conditions can be corrected by soil drainage 



m some cases. 



Soil Acidity 

Blueberries require an acid soil, the ideal pH being 
between 4.5 and 5.5. If the pH is below 4.5, dolomitic or 
high magnesium limestone should be applied to raise the 
pH, while sulfur may be used to lower the pH. In addition, 
fertilizers having an acid reaction should be used, such as 
most complete fertilizers (10-10-10, etc.), ammonium 
sulphate, and ammonium nitrate. Do not use fertilizers 
having an alkaline reaction, such as sodium nitrate, cal- 
cium nitrate, cyanamide, bone meal, and wood ashes, 
unless the pH is 4.6 or lower. 

Nutrients 

It is generally agreed that nitrogen is the most impor- 
tant of the major elements required by blueberries, the 



ammonium form being preferred to the nitrate form. 
Little or no response has been observed to phosphorus or 
potassium applications although one Massachusetts 
grower reports improved growth and production from 
application of superphosphate. In the field, the only 
deficiency symptoms observed are those of nitrogen, iron, 
and magnesium. Symptoms of nitrogen deficiency include 
stunted growth, yellowing, and, under severe deficiency, 
reddening of older leaves. Iron deficiency appears on the 
new growth with the leaves becoming bright yellow, while 
magnesium deficiency usually becomes apparent at har- 
vest as yellowing between the veins and of leaf margins of 
older leaves while veins remain green. Both iron and 
magnesium deficiencies are usually corrected by adjusting 
pH to the optimum range. Environmental factors that can 
be confused with nutrient deficiency symptoms include 
drought stress, poor drainage, cool weather during the 
growing season, insect or disease injury, fertilizer burn, 
and injury from pesticides and herbicides. Therefore, a 
soil test or leaf tissue analysis is advisable if a nutrient 
deficiency is suspected. Soil samples should be taken in the 
fall while leaf samples should be taken from July 15 to 
August 15. 

Fertilizer is usually applied in a ring around the bush 
or in broad bands on both sides of the row. On newly-set, 
young bushes a 6-inch ring around the bush 12 inches from 
the crown is recommended when new growth starts. A 
second application may be made in late June or early July 
and a third in late November before the ground freezes. 

On newly set plants the recommended amount of 



fertilizer is 1 ounce of 10-10-10 or its equivalent. This 
amount may be doubled each year to a maximum of 1 
pound per bush at 5 years. Bushes low in vigor may be 
fertilized again with 1/2 pound in late November. Fertil- 
izer rates may be increased up to twice the recommended 
amount where bushes are heavily mulched. Higher rates 
are needed on sandy soils since nitrogen leaches readily. 



especially in the nitrate form. Lower rates at frequent 
intervals help to minimize leaching. Fertilizers containing 
muriate of potash (potassium chloride) are not advisable 
since the chlorine may be injurious, particularly to young 
bushes. Well rotted manures may be applied in late fall or 
early sprmg using half as much poultry as cow or horse 
manure. 



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Red Fuji is a Promising New Apple Cultivar 

Duane W. Greene and Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 



There is increasing interest on a world-wide basis in 
identifying and evaluating new apple cultivars. Significant 
shifts are occurring, particularly in places such as The 
Netherlands, New Zealand, China, and Japan, from the 
traditional cultivars toward those that have better taste and 
storage characteristics. Of the new cultivars, one of the 
most promising is Fuji, a cross between Ralls Janet and 
DeHcious. It is a medium-sized apple that is green with a 
dull pink or red stripe or blush over a yellow-green ground 
color. Red strains show considerably more, but not out- 
standing, red color. The flesh is yellowish green, dense, 
crisp, and sweet. Fuji is a high quality apple! Several red 
coloring strains have been identified, and they are sold by 
various nurseries. It is the most popular apple in Japan, 
where 44 % of the production is Fuji (including its red 
coloring strains). It is the most widely planted cultivar in 
China and the most talked-about apple in California. 
Growers in the Pacific Northwest also are giving Fuji 
considerable attention. 

At the University of Massachusetts Horticultural 
Research Center, Belchertown, we propagated and 
planted a strain of Red Fuji obtained from Roger Way at 
the New York Agricultural Experiment Station in Geneva. 
The first fruit from these trees were harvested this fall. 
Here we report briefly on the first year's results with this 
strain of Red Fuji. 

Tree Characteristics 

Fuji is a moderate- to high-vigor, non-spur tree. It is 
easily trained to a central leader, and has scaffold branches 
that appear to require no spreading. The tree may have 
some bUnd wood at the base of 2-year-old wood, similar to 
that of nonspur Delicious (one of its parents). It blooms 
mid- to late-season. It is a diploid amd thus should have 
viable pollen capable of pollinating other cultivars bloom- 
ing in the same season. In 1988 it set more fruit in our 
planting than similar Marshall Mcintosh trees. Because it 



blooms and sets fruit at an early age, control of growth in 
the orchard should not be difficult. Reports from else- 
where suggest that it is susceptible to fire blight but may 
have some resistance to apple scab. 

Fruit Characteristics 

Harvests of Red Fuji were made on October 20 and 24, 
1988. At this time seeds were brown, and severe watercore 
had developed in some fruit. Consequently, we feel that 
the fruit could have been harvested some time prior to 
October 20. Harvest was delayed because of the persis- 
tence of a dark-green ground color. Fruit weight averaged 
about 7 ounces. Because the trees are young, one could 
expect fruit size on older trees to be smaller. Flesh 
firmness was 18.5 pounds. Soluble solids (sugar) was over 
15%, which is the highest that we have recorded for any 
cultivar evaluated at the Horticultural Research Center. 
The taste was sweet, fruity, slightly aromatic, subacid, and 
pleasant. The fruit surface was slightly rough with raised 
lenticels. The overall exterior appearance was very similar 
to a well-colored Baldwin. We would rate the overall 
quality of Red Fuji to be good but not exceptional. How- 
ever, it is reported that Fuji does not produce a high quality 
fruit on young trees. Fruit is now in air storage for periodic 
evaluation of its storage potential. 

We believe that Red Fuji is worthy of trial in Massa- 
chusetts. Anyone who can mature Rome should be able to 
mature Fuji. Based upon reports from other parts of the 
country and from Australia, we believe that fruit color and 
possibly taste of Fuji grown in Massachusetts may be as 
good as, if not superior to, those fruit grown in other 
regions. If the potential for Fuji is greater than that for 
Granny Smith, as some have suggested, then Red Fuji is a 
cultivar that growers in Massachusetts should be watching 
very carefully. 



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10 



Apple Rootstocks for the 1990's 

Wesley R. Autio and Duane W. Greene 

Department of Plant & Soil Sciences, University of Massachusetts 



The ideal apple tree is determined by fitting the 
rootstock with the cultivar, site, training system, and the 
orchardist's perception of what makes a good tree. The 
introduction of a number of new rootstocks presents fruit 
growers with many options for the future. Many of these 
rootstocks are not tested, although research is being 
conducted around the world to evaluate them. The 
purpose of this article is to report on the results of 2 NC- 
140 Rootstock Research Committee plantings in 
Massachusetts that contain some of the most promising 



new rootstocks. 

The most thorough and extensive evaluation of 
rootstocks in North America is carried out through the 
NC-140 Rootstock Research Committee. This committee 
is a group of approximately 50 pomologists from the U.S. 
and Canada. Each year the group meets to share data and 
observations on present plantings and to plan future, 
cooperative, uniform plantings. At present 2 apple 
rootstock plantings are in the ground, and 2 new plantings 
are scheduled for 1990. The oldest of the two plantings was 



Table 1. Trunk circumference 


yield, yield efficiency. 


and fruit we 


ght of Starkspur Supreme 


DeUcious on various rootstocks planted in 


1980 and 1981 


Cumulative 


yields and yield efficiencies 


represent data from 1983 and 1984 through 1988 for the 1980 and 1981 plantings, respectively. 










Yield efficiency 






Trunk 
circumference 


Yield per tree (bu) 


(kg/ 


cm^) 


Fruit 

* 1_* 












weight 


Rootstock 


(in) 


1988 


Cumulative 


1988 


Cumulative 


(oz) 


1980 Planting: 














Ott.3 


8.1 be' 


1.2 be 


7.6 b 


0.68 a 


4.15 be 


8.0 ab 


M.7 EMLA 


11.9a 


3.6 a 


12.5 a 


0.95 a 


3.27 c 


7.1 be 


M.9 EMLA 


6.4 cd 


1.0 be 


6.0 be 


0.83 a 


5.32 a 


8.5 ab 


M.26 EMLA 


9.3 b 


1.8 b 


8.9 b 


0.76 a 


3.80 be 


8.1 ab 


M.27 EMLA 


3.5 e 


0.3 c 


1.4 d 


0.68 a 


3.95 be 


7.4 abc 


M.9 


4.7 de 


0.3 c 


2.6 cd 


0.47 a 


4.23 abc 


7.9 ab 


MAC 9 


8.4 b 


1.0 be 


9.0 ab 


0.49 a 


4.54 ab 


9.1a 


OARl 


9.6 b 


1.2 be 


3.8 cd 


0.46 a 


1.51 d 


5.8 c 


1981 Planting: 














Ott.3 


7.2 bed 


1.5 ab 


6.8 ab 


1.15 abc 


4.73 ab 


8.4 ab 


M.7 EMLA 


9.9 a 


2.1a 


7.6 a 


0.81 abc 


2.85 cd 


7.8 ab 


M.9 EMLA 


6.4 cd 


1.6 ab 


6.1 abc 


1.45 a 


5.38 a 


8.5 ab 


M.26 EMLA 


8.3 abc 


2.3 a 


7.5 a 


1.22 ab 


3.98 abc 


7.9 ab 


M.27 EMLA 


5.2 e 


0.2 c 


0.8 d 


1.14 abc 


3.45 be 


7.2 ab 


M.9 


6.8 d 


0.4 be 


3.0 cd 


0.48 be 


3.93 abc 


8.7 ab 


MAC 9 


6.8 cd 


0.4 be 


5.3 abc 


0.33 c 


4.15 abc 


9.6 a 


OARl 


9.0 ab 


1.4 abc 


3.4 bed 


0.61 be 


1.49 d 


6.5 b 


'Means within 


plantings and columns not 


followed by the same letter are significantly 


different 


at odds of 19 to 1. 













11 



established at 27 locations in 1980 and 1981 and includes 
Starkspur Supreme Delicious on M.7 EMLA, M.9 EMLA, 
M.26 EMLA, M.27 EMLA, M.9, OAR 1, Ottawa 3, and 
MAC 9 (the virus-indexed version of which is now being 
sold as "Mark"). This planting was established as a 
randomized complete block with 10 replications. Trees in 
half of the replications (those planted in 1981) were staked 
at planting, while trees in the other half (those planted in 
1980) were staked only when they leaned more than 45° 
from vertical. Each year the height, spread, trunk 
circumference, and yield from each tree is measured. 

The younger NC-140 planting was established in 1984 
and includes Starkspur Supreme Delicious on Bud.9, 
Bud.490, P.l, P.2, P.16, P.18, P.22, MAC 1, MAC 39, CG- 
10, CG-24, M.4, M.7 EMLA, M.26 EMLA, C.6, Ant.313, 
and domestic seedling in a randomized complete block 
design with 10 replications. Trees have been staked only 
when they have leaned more than 45° from vertical. 

Table 1 presents the trunk circumference and yield 
data from the 1980 and 1981 plantings. The discussion 
here will focus on the 3 most interesting rootstocks in the 
1980/81 planting: M.9 EMLA, Ott.3, and MAC 9 (Mark). 

The EMLA designation refers to those rootstocks 
derived from clones which have had the latent viruses 
removed. They were developed by a cooperative effort of 
the East Mailing and Long Ashton Research Stations in 
England. In general, the EMLA series rootstocks are very 
similar to the rootstock from which they were derived, e.g.. 



M.7 EMLA is very similar to M.7 or M.7A. In some cases 
vigor may be slightly greater for the EMLA version; 
however, M.9 EMLA is considerably more vigorous and 
productive that M.9 (Figure 1). M.9 EMLA actually was 
derived from a different strain of M.9 than we commonly 
use. The trunk circumference after the 1988 growing 
season of trees on M.9 EMLA was 28% greater than those 
on M.9. The 1988 yield per tree was 308% larger, and the 
cumulative yield per tree from 1983 through 1988 was 
118% greater. Another way to look at yield is in terms of 
yield efficiency (Table 1), which is given as yield per unit of 
trunk cross-sectional area. This term accurately relates 
tree size and yield per tree and allows a comparison of 
potential productivity. On a cumulative basis through 1988 
the trees on M.9 EMLA were 30% more yield efficient 
than those on M.9. 

In general, M.9 EMLA may result in a tree which is 
too vigorous for a trellis; however, trees on M.9 EMLA 
may be a superior tree on a post trained to a slender spindle 
or a similar system. It is necessary to consider cultivar 
when choosing between M.9 and M.9 EMLA and among 
the various training systems. These observations are based 
primarily on a low-vigor cultivar: Starkspur Supreme 
Delicious. With a vigorous scion M.9 may produce an 
excellent posted tree, and M.9 EMLA may result in a tree 
too large for a high density planting. With a low-vigor 
cultivar the vigor induced by M.9 EMLA may be necessary 
to allow the development of even an adequate trellised 




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Figure 1. Starkspur Supreme Delicious on M.9 EMLA (left) and M.9 (right) after 8 growing seasons (1981 
planting). 



12 



tree. 



Ottawa 3 (Figure 2) is a hardy rootstock which may 
hold a great deal of promise. It results in a tree similar in 
size to M.26 EMLA with a similar yielding potential. On 
a cumulative basis through 1988 the yield efficiency (Table 




Figure 2. Starkspur Supreme Delicious on Ott.3 
after 9 growing seasons (1980 planting). 



1) of trees on Ott.3 was second only to those on M.9 
EMLA. Trees on Ottawa 3 appear to be sUghtly better 
anchored than those on M.26 EMLA but in most cases will 
require support. Ripening studies (data not shown) 
suggest that Ott.3 may advance ripenmg. 

MAC 9 (Mark) (Figure 3) is probably the most 
interesting rootstock in the study. Tree size after the 1988 
growing season was similar to that of trees on M.26 and 
Ott.3 (Table 1), and it has been one of the most productive 
trees in the planting. On a cumulative basis through 1988 
trees on MAC 9 were 12% more yield efficient than trees 
on M.26 EMLA. An inherently high level of precocity can 
be a problem with MAC 9, especially with weak cultivars. 
Excessive fruiting can result in very little growth and 
"runting out" of the trees. Once growth has stopped due 
to excessive cropping it is difficult to get trees to grow 
again. Because of the limits of the uniform planting we did 
not thin the fruit in 1987 when the crop was excessive, thus 
fruit size and growth were reduced significantly in 1987 and 
the crop was very light in 1988. Trees on MAC 9 (Mark) 
in a commercial planting must be thinned early in their life 
to maintain good growth and fruit size. Our observations 
suggest that MAC 9 is only somewhat better anchored than 
M.26 EMLA, so we feel that in most cases it will benefit 
from support, at least during the first 5 years in the ground 
when tree structure is being estabUshed. Ripening studies 
(data not shown) suggest that MAC 9 delays ripening, 
which may be a very useful tool for expanding the harvest 




Figure 3. Starkspur Supreme DeUcious on MAC 9 (Mark) (left) and M.26 EMLA (right) after 8 growing 
seasons (1981 planting). 



13 



season of a single cultivar in commercial settings. 

The 1984 NC-140 planting is at this time too young to 
make any accurate statement about specific rootstocks. 
However, data on tree size and yield are presented in Table 
2, and this information can be used to get some idea of the 
basic relationships among these rootstocks. After the 1988 
growing season the smallest trees were on P. 16 and P.22, 
and the largest were on P.18, CG-10, Ant.313, and 
domestic seedling. On a cumulative basis the most 
efficient trees were on P.2, P.16, Bud.9, C.6, and P.22. The 
rootstocks with the most promise are Bud.9, P.2, and C.6. 
All are between M.9 and M.26 in their size controlling 
properties, and all trees on these rootstocks will need 
support. Representative trees on these rootstocks are 
pictured in Figures 4, 5, and 6. We will be observing this 
planting for the next 5 years to see where some of these new 
rootstocks might fit into our production systems. 

The next plantings of the NC-140 Rootstock Research 
Committee are scheduled for 1990. One planting will look 
at the interaction of rootstock and training system and the 
second will study the interaction of rootstock and cultivar. 
In the rootstock/cultivar planting we are trying to 
eliminate the problem of evaluating a rootstock based 





1 ^^'**«! 
1 






r 


















■ *^ 






■§: 










Figure 4. Starkspur Supreme Delicious on Bud.9 


after 5 growing seasons (1984 planting). 



Table 2. Suckering, trunk circumference. 


yield, yield efficiency, and fruit weight of Starkspur Supreme 


Delicious on various rootstocks 


planted in 


1984. Cumulative yields anc 


yield efficiencies represent data | 


from 1987 through 


1988. 
















Root 








Yield efficiency 






suckers 


Trunk 


Yield per 


tree (bu) 


(kg/cmO 


Fruit 
weight 




per tree circumierence 








Rootstock 


(1984-88) 


(in) 


1988 


Cumulative 


1988 


Cumulative 


(oz) 


Bud.9 


0.0 c 


4.7 efg 


0.8 abc 


1.2 abc 


1.31 ab 


2.04 ab 


7.1 abc 


MACl 


3.9 abc 


7.2 be 


0.4 def 


0.5 f 


0.28 f 


0.32 d 


7.3 abc 


MAC 39 


0.0 c 


4.7 efg 


0.7bcde 


0.8 cdef 


1.08 abed 


1.34 be 


8.2 a 


P.l 


0.7 be 


6.8 bed 


1.1a 


1.6 a 


0.91 cd 


1.31 be 


7.7 ab 


P.22 


0.7 be 


3.0 h 


0.3 f 


0.5 ef 


1.02 bed 


1.98 ab 


6.8 be 


Seedling 


7.0 abc 


8.4 ab 


0.5 cdef 


0.6 ef 


0.25 f 


0.31 d 


7.1 abc 


CG-10 


9.2 a 


8.1 ab 


0.4 ef 


0.4 f 


0.28 f 


0.34 d 


7.2 abc 


CG-24 


3.9 abc 


7.2 be 


0.5 cdef 


0.6 def 


0.39 ef 


0.44 d 


6.8 be 


M.4 


0.8 be 


7.2 be 


0.6bcdef 


0.8 cdef 


0.48 ef 


0.62 cd 


7.1 abc 


M.7 EMLA 


0.4 be 


6.3 cde 


0.8 abc 


1.1 abed 


0.74 de 


0.%cd 


7.5 abc 


M.26 EMLA 


3.3 abc 


5.3 def 


0.8 abed 


l.Obcde 


1.00 bed 


1.37 be 


7.7 ab 


Bud.490 


1.0 abc 


7.5 abc 


0.7bcde 


0.8 cdef 


0.46 ef 


0.55 d 


7.6 ab 


P.2 


0.0 c 


4.1 fgh 


0.7bcde 


l.Obcde 


1.53 a 


2.18 a 


7.0 abc 


P.16 


0.6 be 


3.4 gh 


0.3 ef 


0.6 ef 


1.21 abc 


2.20 a 


6.3 c 


P.18 


0.8 abc 


8.1 ab 


0.7bcde 


0.8 cdef 


0.38 ef 


0.46 d 


7.9 ab 


C.6 


0.5 be 


5.3 def 


0.9 ab 


1.4 ab 


1.15 abc 


1.83 ab 


8.3 a 


Ant.313 


7.3 ab 


8.4 ab 


0.6bcdef 


0.8 cdef 


0.37 ef 


0.48 d 


7.7 ab 


'Means within columns not followed by the same letter are significantly 


different at odds of 19 to 1. 



14 



'•^^J:^r%^^"-~ 




Figure 5. Starkspur Supreme Delicious on P.2 
after 5 growing seasons (1984 planting). 



solely on data from one cultivar. It will contain 4 cultivars 
(Golden Delicious, Jonagold, Empire, and Law Rome) 
and 5 rootstocks (M.26 EMLA, M.9 EMLA, Mark, Ott.3, 
and Bud.9) at ail cooperator locations. Cultivars to be 
planted at some locations include Marshall Mcintosh, 
Stayman, Red Yorking, Liberty, Jonathan, Chieftain, 
Mutsu, Gala, and Granny Smith. Rootstocks which will be 
planted at some locations include P.22 and M.27 EMLA. 
With this planting we hope to evaluate cultivars of different 
basic growth types on the most promising rootstocks to 
give a better idea of how these rootstocks will perform. 

Proper selection of a rootstock will be a significant 
factor in apple production in the future. The choice of the 
most appropriate rootstock will depend on a number of 
factors including cultivar, training system, soil, and time of 
ripening. An unprecedented number of new rootstocks 
presently are under intensive evaluation. The prominent 
rootstocks of the future likely are among those being 
tested. 




~.iyj^dQtei i^i T^fittiiaiiii til |-'>^ ^•H'^ 



Figure 6. Starkspur Supreme Delicious on C.6 (left) and M.26 EMLA (right) after 5 growing seasons (1984 
planting). 



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W^ W^ ^« ^% ¥^ 



15 



Apple IPM Program: 

Delivery and Observations in 1988 

Kathleen P. Leahy, Ronald J. Prokopy, Susan A. Johnson, and William M. Coli 
Department of Entomology, University of Massachusetts 

Daniel R. Cooley 

Department of Plant Pathology, University of Massachusetts 

James T. Williams 

University of Massachusetts Cooperative Extension, Concord, MA 



Our thanks to the following cooperating growers in 
the IPM monitoring program this year: Charlie and Alex 
Dowse, Ed Jensen, Tony Lincoln, Tony Rossi, Don Sch- 
licke, Steve Smedberg, Mike and Tim Smith, Mike Smo- 
lak, and Denis Wagner. Special thanks to Sue Butkewich 
for technical assistance. 

Ovendew of the Program 

The 1988 Massachusetts Apple Integrated Pest Man- 
agement (IPM) Program was a mixture of "old" and new 
approaches to orchard pest management. As always, we 
monitored commercial blocks for insect and disease activ- 
ity and reported the information to the state's growers, via 
newsletters, recorded Code-A-Phone messages, and di- 
rect grower access of INFO^fET, our computerized bulle- 
tin board system. Some pesticide trials and other related 
research was conducted at the University of Massachusetts 
Horticultural Research Center, Belchertown. In addition 
to these activities, however, we are now working toward 
melding our more-proven, first-stage-IPM pesticide-re- 
duction practices with some of the more-radical practices 
involved in second-stage IPM into a unified "third stage" 
of greatly reduced pesticide use without loss of crop quality 
or profitability. 

Monitored blocks (7 out of 9 blocks reporting pesti- 
cide records) received an average of 4.3 dosage equivalents 
(full-rate equivalents) of insecticide this year, 0.9 DE's of 
miticide, and 8.5 DE's (range of 5.4 to 12) of fungicide. 
This reduction in overall pesticide use did not result in any 
loss of crop quality, premature fruit drop, or other prob- 
lems in these blocks. One spray-related problem was 
brought to our attention which had appe2ired in some 
locations: a russetted ring towEwd the low-hanging end of 
the fruit. This injury was tentatively attributed to Captan 
applied on a hot (88°?) day under poor drying conditions. 



Insects and Diseases in 1988 

European Apple Sawflv . Captures were quite high in 
blocks where sawfly was not well controlled last year; one 
block even exceeded our record high trap captures of 1987 
with an average of 73 per trap and a maximum of 126! Trap 
captures were moderate in most blocks; however, sawflics 
entered in such a way that many growers were unable to 
protect earlier cultivars when later cultivars were still in 
bloom. Sawfly damage was seen in blocks where pre- 
bloom sprays were applied as well as where such sprays 
were withheld. 

Plum Curculio . Curculio activity also occurred in a 
very concentrated period at bloom and petal fall. Injury 
was exceptionally high in some blocks where controls 
could not be applied in time. Very little fresh injury was 
seen or reported in the 9 regular monitoring blocks after 2 
to 3 weeks past petal fall. Some growers, particularly those 
who often experience late curculio injury, did, however, 
report serious problems with late curculio activity this 
summer. 

Pear Thrips . This insect became a major problem in 
at least 3 orchards in western Massachusetts as well as in 
Vermont, causing poor fruit set in infested blocks (ap- 
proximately 75% yield reduction in one case). Thrips have 
been present in low-spray orchards in this area since 1985, 
but this year was their first major appearance in commer- 
cial blocks in Massachusetts. 

Leafminers . This year was another unusual year for 
leafminer activity. Spring emergence seemed fairly stable 
and predictable (unlike that of 1987, when cold and snow 
made emergence highly erratic), and growers who had 
leafminer problems, for the most part, were able to time 
their sprays well. However, the second and third genera- 
tions, increased to unexpectedly high levels, even where the 
first generation appeared to be adequately controlled, or 



16 



where first-generation mines indicated that populations 
were too low to worry about. Premature drop did not 
appear to be a problem in any infested block, however. 

Larvae of the apple-and-thorn skeletonizer (An- 
thophilapariana) were present in one orchard in fairly high 
numbers, but were completely controlled by an insecticide 
directed against apple maggot fly in early August. Apple 
leafminer (Lyonelia speculella) was also found in a few 
locations this year, but no problems were observed. 

Tarnished Plant Bug . Plant bug captures on white 
rectangle traps were unusually low throughout the pre- 
bloora period, not reaching cither the tight cluster or pink 
threshold in any monitored block. For this reason, some 
growers were able to withhold insecticides directed against 
plant bug this year. Plant bug damage at harvest was less 
than in previous years; of the injury that did appear, much 
could have been either sawfly (calyx stings) or green 
fruitworm/oblique-banded leafroUer (large russetted 
dimples) injury. 

Leafrollers . More oblique-banded Icafroller injury 
was seen than is usual this year in monitored, first- and 
second-stage IPM blocks, but still did not appear to be at 
a level of concern. Early-season leafroller damage was 
found in some blocks, especially low-spray blocks; this type 
of injury is unusual in Massachusetts. Apparently the small 
window of sawfly/curculio activity and control gave the 
leafrollers a chance to move in after petal fall. Pesticide 
resistance on the part of oblique-banded leafroller is also 
a possibility, although damage was more notable in lightly- 
sprayed blocks than in heavily-sprayed blocks. Overall 
leafroller injury remained very low, however, amounting to 
less than 0.2% of surveyed fruit. 

A pple Maggot Fly . Overall maggot fly pressure was 
low, and very little damage was found. There did not 
appear to be a late-season flush of apple maggot fly 
activity, as there has been for the last few years. 

Aphids . Aphids were eventually controlled by preda- 
tors, but populations tended to hang on longer than usual, 
especially on water sprouts, where they could be found 
until mid-July in some blocks. This delayed effect could 
have been due to the presence of spiraea aphids in addition 
to green apple aphids, or to some other factor. No 
honeydew problems were seen in any monitored block. As 
in 1987, cecidomyiid midge larvae were the predominant 
predator, ably assisted by syrphid fly and camaemyiid fly 
larvae, minute pirate bugs, ambush bugs, and ladybird 
beetles. 

Ladybird Beetles . Populations of ladybird beetles 
were noticeably higher statewide this year than in previous 
years. 

Mites /Predators . Mite activity appeared to level off in 



late summer; some growers who had originally planned to 
treat decided to wait, and ultimately did not need a miticide 
at all, or were able to use a low rate or spot treatment. 
Once again, dormant oil appeared to be a highly effective 
method of preventing mite buildup. Miticide use averaged 
close to 1 DE in 9 commercial blocks, down from the usual 
average of 2 DE of miticide (not including dormant oil). 
Summer oil at 1 quart/ 100 gallons was used successfully in 
one monitored block, with no apparent ill effect on fruit or 
foliage. Predators continue to build in commercial or- 
cha.r(is\Amblyseius fallacis and Zetzellia mali built up later 
than usual, and were lower in number than in 1987, but 
were still of value in several blocks. Rain in late summer 
probably also helped wash mites off leaves. 

Lcafhoppers . Potato leafhopper was not much in 
evidence this year, except in one low-spray block of young 
trees, where it disappeared entirely after an organo- 
phosphate insecticide was applied. White apple leafhop- 
per was at a problem level in one first-stage and a few 
second-stage IPM blocks, but overall it did not present a 
major problem this year. 

Catfacing Insects . Activity was very low to moderate 
in peach blocks this year. Many growers reduced insecti- 
cide use with no noticeable ill effects. 

Earwigs . Several instances of earwig injury to apples 
in commercial orchards occurred, especially on Cortland 
fruit. Injury was most often in the stem end and took the 
form of chewing as well as substantial frass accumulation. 
It was not possible to tell whether the earwigs had initiated 
the injury or only moved in later and enlarged previous 
wounds. 

Scab . There were only 5 or 6 (depending on location) 
actual scab infection periods, though the length of these 
generally exceeded 36 hours. Frequent wetting periods, 
which were not Mill's periods, occurred during primary 
season. The timing of sprays was difficult due to the length 
of the wetting periods, and windy weather. Growers who 
missed a spray, or even missed a few trees, had some 
trouble for the rest of the season which would have been 
worse except for the dry summer weather. The average 
fruit scab injury for IPM monitoring blocks was generally 
low (0.47%) except for one block where mechanical break- 
downs interfered with the scab spray schedule, and injury 
was 5.5%. 

Sooty Blotch and Flvspeck . These problems were 
evident in a number of blocks, especially on Golden Deli- 
cious apples. 

Calyx End Rot. Black Rot, etc. Very little of any of 
these problems were noted in monitored blocks, especially 
when compared to the levels reported in previous years. 
There were some instances of Botrytis-mAaceA end rot 



17 



>- 
a: 



1.500 



1.000 



^ 0.500 -- 



0.000 




ES 1978-87 
ES 1988 



jaJ 



Nixi 



[^ R ^ 



PB EAS PC LR AMF GFW CM S, 



S. 



S OTHER 



Figure 1. Insect injury on fruit in 1988 (percent of 8000 fruit evaluated) compared with 1978-87. (TPB = 
tarnished plant bug, EAS = European apple sawfly, PC = plum curculio, LR = leafroller,AMF = apple maggot 
fly, GFW = green fruitworm, CM = codling moth, SJS = San Jose scale.) 






^ 



1.500- 

1.250- 

1.000 

0.750 

0.500 

0.250 

0.000 



I 



$^ 



i 



ES 1978-87 
ES 1988 



i 



m- 



1 



SCAB CALYX BLACK SOOTY OTHER 

END-ROT ROT BLOTCH/ 

FLYSPECK 
Figure 2. Disease injury on fruit in 1988 (percent of 8000 fruit evaluated) compared with 1978-87. 



18 



which did not progress into the apple. 

Fire Blight . Except for a limited occurrence on young 
Gala and a block of exotic (British cider) cultivars, fire 
blight was not a major problem on apples in 1988. This 
observation was interesting, since 2 pear blocks had very 
heavy fire blight damage, and other pear growers had 
limited problems. Possibly growers are regularly using 
dormant materials on apples but not on pears. Of course, 
pears generally are more susceptible, but have not had 



more fire blight than apples in recent years. 

Bitter Rot . Isolated incidence of bitter rot at eco- 
nomic levels (>5%) occurred in one Massachusetts or- 
chard. This outbreak was probably related to the unusual 
heat and humidity. Also, drops had not been removed 
from the block for 2 years. 

Figures 1 and 2 show the insect- and disease-related 
fruit injury which occurred in 1988 compared with 1978-87. 



»s* ^* ^« •$« »s^ 

0^ wgm ^9 «^ w^ 



19 



COOPERATIVE EXTENSION 

U S. DEPARTMENT OF AGRICULTURE 

UNIVERSITY OF MASSACHUSETTS 

AMHERST, MASSACHUSETTS 01003 0099 



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Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

University of Massachusetts Cooperative Extension, n\ry\ OGICAL 

United States Department of Agricultm-e, and Massachusetts Counties Cooperating. : 



ISSN 0427-6906 



Editors: Wesley R. Autio and William J. Bramlage 







Volume 54, Number 2 
SPRING ISSUE, 1989 

Table of Contents 



Life Without Alar 

Apple Bruising. IV. Injury Occurring During 
Harvest and Transport to the Packinghouse 

The Effects of Summer Pruning on Insect 
and Mite Populations in Apple Trees 

New Trap-capture Thresholds for Tarnished Plant Bug and 
European Apple Sawfly in Massachusetts Apple Orchards 

Diagnosing Leaf Injury Symptoms 

Integrated Pest Management for Commercial 
Strawberries in Massachusetts 

Planting Orchards in Massachusetts 



Fruit Notes 

Publication Information: 

Fruit Notes (ISSN 0427-6906) is published the first day of January, 
April, July, and October by the Department of Plant & Soil Sciences, 
University of Massachusetts. 



The costs of subscriptions to Fruit Notes are $4.00 for United States 
addresses and $6.00 for foreign addresses. Each one-year subscrip- 
tion begins January 1 and ends December 31. Some back issues are 
available for $1.00 (United States addresses) and $1.50 (foreign 
addresses). Payments must be in United States currency and should 
be made to the University of Massachusetts. 



Correspondence should be sent to: 

Fniit Notes 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

University of Massachusetts 

Amherst, MA 01003 



COOPERATIVE EXTENSION POUCY: 

All chemical usessuggested in this publicalion are contingent upon continued registration. Thesechemlcals should be 
used in accordance with federal and state laws and regulations. Growers are urged to be familiar with all current slate 
regulations. Where trade names are used for identification, no company endorsement or product discrimination is 
intended. The University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied, 
concemingthe use of these products. USER ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY 
DAMAGE 



Issued by tht University of Massachusetts Cooperative Extension, E. B. MacDougatt, Director, in furtherance of the acts of 
May 8 and June 30, 19} 4. The Universilyof Massachusetts Cooperative Fjiensionoffersequalopportunit\'inprogramsand 
employment. 



Life Without Alar 



Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 



In August, 1985 the controversy began regarding 
the safety of Alar^*^ residues on apples. Since that time 
many discussions and arguments have occurred. A 
recent "60 Minutes" program fueled the controversy 
by presenting claims made by the Natural Resources 
Defense Council that Alar is a potent carcinogen. The 
scientific data available certainly do not support that 
view; however, the widespread publicity likely will 
eliminate Alar-use as a hoilicultural practice. Apple 
growers must look toward a future without Alar. In 
this aiticle I shall present some of the ways that may 
help reduce the need for Alar. 

Before discussing specific activities, we must be 
clear on what benefits are received from Alar. The first 
and foremost function of Alar is to act as a "stop-drop." 
This function allows a grower to harvest most of his 
crop before it drops to the ground. By allowing fruit to 
remain on the tree longer they are able to color more 
fully, giving higher grade fruit. One reason why fruit 
stay on the tree longer is that Alar delays the beginning 
of fruit ripening, which results in less-ripe fruit for 
storage, which then allows the fruit to retain high 
quality for a longer time. In particular, the apples stay 
firm for a longer period of time. 

Alternative approaches to the use of Alar must 
address these benefits that Alar provides. Approaches 
will be divided into two types: short-term practices and 
long-term changes. Short-term practices include sev- 
eral activities, but in general these are practices which 
may be undeilaken this season to reduce the losses 
associated with the non-use of Alar. Long-term 
changes require more time and capital to implement. It 
must be understood that Alar provided a gi'eat deal of 
benefit, and no practices are real alternatives: they only 
assist in reducing the losses associated with non-use of 
Alar. 

Short-Term Practices 

Pruning 

Several Fruit Notes articles [52(3):7-8; 53(1):12- 
13; 53(2): 1; and 53(3): 1-2] have discussed the effects of 
pruning, particularly summer pruning, on the produc- 
tion of high quality fruit. Removal of upright, hanging, 
and shade-causing wood in the summer can result in a 



dramatic increase in light penetration, fruit coloration, 
and packout. Additionally, it causes earlier coloration 
and thus allows earlier harvest, hopefully reducing 
some of the need for Alar while not reducing average 
fruit quality. Dormant pruning also is important, 
specifically in improving light penetration to the fruit. 
For more specific information about summer pruning 
practices, see Fruit Notes 53(2):1, and for more infor- 
mation about dormant pruning to improve packout, 
see Fruit Notes 53(1):12-13. 

Chemical Treatments 

There are no chemical alternatives to Alar. How- 
ever, there are two chemicals that can be used to 
expand the harvest season: Ethrel and NAA. The 
problem with both chemicals is that they may render 
the fruit unusable for long-term storage by advancing 
ripening. Ethrel is used to advance the hai^vest season 
by breaking down to ethylene and triggering ripening. 
Treatment with Ethrel results in marketable fruit 
early in the season, but also fruit that probably must be 
consumed immediately, because they are too ripe to 
store. NAA is a "stop drop." It will significantly delay 
premature fruit drop, but it also advances fruit ripen- 
ing. NAA can expand the season, but treated fruit 
must be sold relatively quickly. Details on the use of 
both of these chemicals are given in the New England 
Apple Spray Guide. 

Harvest and Storage Management 

Without Alar the fruit in storage probably will be 
riper than what growers are used to. To maintain fruit 
quality throughout the storage period, the fruit must 
be handled with greater attention to details than if they 
had been treated with Alar. This additional care in- 
cludes more accurate attention to cooling and to the 
rapid establishment and maintenance of optimal tem- 
perature and atmosphere conditions, as well as to 
application of the appropriate postharvest chemical 
treatments. No longer will sloppy storage manage- 
ment be acceptable, since the fruit will show the quality 
of storage management more readily than before. In 
addition to storage management, the intensity of har- 
vest management must be increased. Growers must 
accurately manage their harvest so that the most ap- 



FruU Notes, Spring, 1989 



propriate fruit are placed in long-term storage. This 
practice may include the more frequent use of the 
starch-iodine test for maturity assessment. 

Increased Labor 

Increasing harvest labor so that more fruit can be 
picked in a shorter period of time is one way to reduce 
the impact of the non-use of Alar; however, growers 
must be able to handle the increased quantity of fruit. 
Specifically, the orchard operation must be able to 
move the fruit quickly from the orchard to the storage, 
stack them in the storage, cool them quickly, and seal 
the storage (if CA is used) if the increased labor is going 
to pay off. Beside the availability of additional labor, 
one problem which may prevent this practice from 
being feasible is the size of the refrigeration plant. If 
there is not adequate refrigeration to cool the high 
quantity of fruit being placed in the storage per day 
then the additional labor is not truly reducing the 
impact of the non-use of Alar. 

Long-term Changes 

Changes in Cultiuars 

One of the characteristics of the New England 
apple industi-y which has increased the problems re- 
lated to the loss of Alar is the large proportion (60 %) of 
the production devoted to Mcintosh. A relatively 
simple way of reducing the need for Alar is to replace 
Mcintosh with other cultivars which allow an expan- 
sion of the harvest season or do not require a chemical 
"stop-drop." Several cultivars have potential in New 
England, such as Gala, Mutsu, Libeiiy, Jonagold, and 
Red Fuji. Older cultivars like Coitland and Macoun 
also may deserve a greater role in the industry. Obvi- 
ously, severed years are required to change cultivars, 
and several years are required to develop markets for 
new cultivars. 

Changes in Strains 

Several Mcintosh strains are now available. 
Marshall Mcintosh has been the most planted strain 
over the last few years, primarily because of its higher 
coloring potential. Additional benefits which come 
from Marshall Mcintosh are given by its earlier color- 
ing and earlier ripening. It colors approximately 10 
days prior to Rogers Mcintosh and ripens approxi- 
mately a week earlier. These two differences allow an 
advancement of the Mcintosh harvest season without 
the kind of quality loss found with the use of a chemical 
such as Ethrel. However, planting entirely to Marshall 
Mcintosh will not reduce the losses associated with the 



non-use of Alar, because the entire harvest season will 
be earlier and just as concentrated as with a standard 
strain of Mcintosh. Future orchards should have a mix 
of Marshall Mcintosh with other strains to allow the 
maximum expansion of the harvest season. 

Pioneer Mac (recently named by Adams County 
Nursery) technically is not a strain of Mcintosh but 
actually is a seedling of Mcintosh and thus a new 
cultivar; however, its fruit are virtually indistinguish- 
able from Mcintosh and undoubtedly will be accepted 
as Mcintosh. Its reported advantage over standard 
Mcintosh is that it ripens 2 weeks later. In 1988 at the 
University of Massachusetts Horticultural Research 
Center we established a replicated trial to compare 
Pioneer Mac to Marshall Mcintosh and Rogers Mcin- 
tosh. When information is available it will be reported 
through Fruit Notes. The benefits of Pioneer Mac may 
be great, but as with Marshall Mcintosh it will be 
necessary to include earlier-ripening strains of Mcin- 
tosh to provide a true expansion of the hai-vest season. 

Rootstocks 

Changes in rootstocks must occur to give benefits 
in two areas. First, more dwarfing rootstocks must be 
used. Large plantings of Mcintosh as semi-dwaif trees 
will not be feasible to maintain without Alar. Growers 
must consider moving into the dwarf categoiy, using 
M.9, M.9 EMLA, M.26, Mark, and possibly Ott.3 as 
rootstocks. Trees on these rootstocks are much easier 
to prune, require less spray material, and most impor- 
tantly, in the context of this article, are much easier to 
harvest than are semi-dwarf or standard trees. Nearly 
all the fruit are harvestable from the ground, and the 
harvesting process can be done more rapidly. Because 
of high light penetration into the canopy, more of the 
fruit are highly colored, making selective hai-vesting 
less of a priority while improving packout. For more 
general information on these dwarfmg rootstocks see 
Fruit Notes [51(4):22-24; 52(l):l-4; 53(l):4-7; 53(3):3- 
6;and54(l):ll-15]. 

The second potential benefit of a change in root- 
stocks is their effect on ripening. For three years we 
have been conducting research at the University of 
Massachusetts Horticultural Research Center on the 
effects of rootstocks on apple fruit quality and ripening 
[see Fruit Notes 52(2):5-10], and have found that Mark 
can delay ripening of Delicious and Mcintosh fruit by as 
much as 5 days when compared to fruit from trees on 
M.26 EMLA and Ott.3. The use of rootstock to expand 
the harvest season should complement the use of dif- 
ferent strains to expand further the Mcintosh hai-vest 
season. 



Fruit Notes, Spring, 1989 



Conclusions 

We do not have any easy answers to the question of 
what an apple grower can do to reduce the losses 
associated with the non-use of Alar. Short-term ap- 
proaches, obviously, are stop-gap measures which may 



somewhat reduce the losses. The long-term changes 
will take time and capital to implement but should go 
far to eliminate the need for Alar. The New England 
apple industry has rough seas ahead, but if growers 
look to the future and begin to make some changes, it 
should be able to weather this storm. 



mjs *t» »i» aS» ^A 

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Apple Bruising. IV. Injury Occurring During 
Harvest and Transport to the Packinghouse 

William J. Bramlage 

Department of Plant & Soil Sciences, University of Massachusetts 



This is the fourth in a series of articles reporting 
findings of a research gi'oup at Michigan State Univer- 
sity on the causes and consequences of bruising to 
apples. The previous articles examined bruising dur- 
ing packing, grading, and subsequent transport [Fruit 



Notes 53(4):15-17, 54(l):6-7, and 54(l):7-9]. Here we 
summarize a report in which sources of bruising dur- 
ing harvest and transport to the packing house are 
examined. 

This report is entitled, "Damage Assessment for 



Table 1. Damage incurred during hand-harvest of Mcintosh apples for 6 
Average damage for all orchards, and range of damage among the 6 orchards 


Michigan orchards. 
, are shown. 






Location 


in bin 






Total bin 




Bottom 




Top 


Avg. 


Range 


Avg. 


Range 


Avg. 




Range 


A. Fruit damage, % 
















Undamaged 
Bruised 
Cut 
Punctured 


14 

86 

2 

4 


5 to 24 

76 to 95 

0to5 

2 to 7 


23 

77 
1 
3 


7 to 41 

59 to 92 

Otol 

lto4 


18 

81 

1 

3 




6 to 29 

71 to 94 

0to3 

1 to5 


B. Bruise frequency, % 
















Bruise diameter 
(inches) 
















1/4 to 1/2 
1/2 to 3/4 
3/4 to 7/8 


86 

13 

1 


74 to 93 
7 to 24 
Otol 


89 

11 

1 


81 to 94 
6 to 18 
Otol 


87 
12 

1 




77 to 93 
7 to 21 
Otol 


1 



Fruit Notes, Spring, 1989 



Table 2. Cumulative damage to Mcintosh apples incurred during harvest and transport to packing 
houses for 6 Michigan orchards. 




Average 


Range 


A. Total damage in bin, % 






Undamaged 
Bruised 
Cut 
Punctured 


6 

93 

1 

4 


Otoll 

88 to 100 

0to3 

2to8 


B. Bruise frequency, % 






1/4 to 1/2 inch 
1/2 to 3/4 inch 
3/4 to 7/8 inch 


91 
8 
1 


88 to 95 
5 to 11 
Otol 


C. Characteristics of orchard transport 




Orchard 


In the orchard 


Orchard to packing house 


1 
2 
3 
4 
5 
6 


Fork lift 

Fork lift; bin trailer 
Fork lift; bin trailer 
Double fork lift 
Fork lift; bin trailer 
Fork lift 


Truck, 4 mi. gravel road 
Truck, 6 mi. paved road 
Truck, 3 mi. paved road 
Fork lift, 0.3 mile lane 
Semi-trailer, 65 mile paved road 
5th wheel trailer, 1.5 mile 
gravel and paved roads 


1 



Apple Harvest and Transport," and was presented by 
S. A. Sargent, G. K. Brown, C. L. Burton, N. L. Schutte 
Pason, E. J. Timm, and D. E. Marshall to the American 
Society of Agricultural Engineers December 15-18, 
1987. It was a cooperative study by the U.S. Dept. of 
Agriculture, Agricultural Research Semce, and the 
Agi'icultural Engineering Department, at East Lan- 
sing, Michigan. 

This study examined damage to Mcintosh apples 
in 6 commercial hand-harvested orchards in Michigan. 
Fruit were sampled from bins when they had 2 or 3 
layers of fruit in the bottom, and again when they were 
full. Fruit in these bins were again sampled at the 
packing houses as they were floated by water from the 
bins, to assess damage that had occurred during bin 
transfer operations. 

All fruit were visually evaluated for bruises, which 
were rated for size (diameter) as "A" = 1/4 to 1/2 inch, 
"B" = 1/2 to 3/4 inch, "C" = 3/4 to 7/8 inch, "D" = 7/ 
8 to 1 1/4 inch, and "E" = greater than 1 1/4 inch. Cut 
or punctured fruit were also recorded. 



Overall, only 18% of the fruit in the bins in the 
orchard were uninjured (Table 1). Eighty one percent 
of them were bruised, 1% were cut, and 3% were 
punctured. As expected, however, injury was more 
prevalent in the bottom than on the top of the bins. 
Most (87%) of the bruises were less than 1/2 inch in 
diameter, and bruise size was about the same for fruit 
in the bottom and at the top of the bin, indicating that 
drop distance was about the same in both locations, 
since bruise size increases with drop height. 

In all orchards, bins were transported by tractor- 
mounted fork lifts. In some cases, bins were moved to 
other parts of the orchard for filling, and 1 orchard used 
a double fork-lift to transport bins from the orchard to 
the packing house. Three operators used self-loading 
bin trailers with low-pressure balloon tires for trans- 
port to roadside. Various trucks and trailers were used 
to transport bins from roadside to packinghouse. Most 
roads were paved, and distances ranged from 1/4 to 7 
miles. 

Following harvest and transpoil, only 6% of the 



FruU Notes, Spring, 1989 



Bruises/Fruit 




Harvest Transport 

Bruises Incurred During: 

Figure 1. Average number of bruises incurred during harvest and 
transport of Mcintosh apples in 6 Michigan orchards. See Table 2 for 
descriptions of transport methods among the 6 orchards. 



fruit were undamaged. Most of the increase in damage 
during transport was from bruising, with very little 
cutting or puncturing occurring after the harvest op- 
eration. Most of the bruises incurred during transit 
were the small, class A type. A high percentage of these 
bruises appeared to be due to repeated vibrations from 
trucks or trailers with "stiff' suspensions. 

The relationships of orchard operation to bruising 
can be seen in Table 2 and Figure 1. Orchard 4 had by 
far the most bruising during harvest, an indication of 
poor instruction and/or supervision of pickers. Or- 
chard 6 produced the most bruising during transport. 
Here, a trailer with "stiff" suspension was used to 
transport bins from the orchard to the packing house, 
a distance of about 1.5 miles over some gravel and some 
paved roads. 

The strikingfeature in Figure 1 is the relatively low 
amount of bruising during transport in Orchards 2, 3, 
and 5, all of which used bin-loading trailers to move 
bins out of the orchard to the roadside. 



Care in bin handling by fork-lift operators can 
greatly reduce the amount of damage incurred when 
settingbins on trailers and floors. In several operations 
fork lifts had short tines which did not extend under 
the entire bin bottom. This caused the bottom boards 
to spring upward during transport, which can bruise 
apples in the bottoms of the bins. 

The authors conclude by recommending (a) gentle 
harvest and placement of apples in bins; (b) careful 
lifting, movement, and setting of bins during transport; 
(c) a minimal number of handling steps, and (d) use of 
appropriate equipment. They recommend use of long 
tines on fork lifts, soft tires, and soft suspensions on 
transport vehicles. Bin-loading trailers were of consid- 
erable benefit in avoiding bruising. 

Figure 1 clearly shows that much bruising during 
harvest and transport is avoidable. The information 
provided in this study should help growers to carefully 
evaluate their operations to identify problems, and 
help to correct them. This can substantially improve 
fruit quality and pack-out. 



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Fruit Notes, Spring, 1989 



The Effects of Summer Pruning on Insect 
and Mite Populations in Apple Trees 

Susan L. Butkewich, Ronald J. Prokopy, and William Pyne 
Department of Entomology, University of Massachusetts 



Wesley R. Autio and Duane W. Greene 

Department of Plant & Soil Sciences, University of Massachusetts 



Summer pruning is one way to reduce setbacks in 
apple production caused by the elimination of Alar^"^ 
from a grower's spray program. Without Alar, fruit 
may drop before they become red enough to yield a high 
marketvalue. In previousissuesofFrwi7iVo/es [52(3);7- 
8, 53(2):1, 53(3): 1-2] the benefits derived from summer 
pruning of Mcintosh trees were illustrated. An in- 
crease in light penetration into the tree from summer 
pruning resulted in 1) earlier coloring of fruit, 2) a 
higher percentage of fruit making the U. S. Extra 
Fancy grade, 3) earlier harvesting of fruit, and 4) 
production of more fruit with a potential for long term 
storage. 

Little is known about the effects of summer prun- 
ing on apple arthropod pests and predators. Pruning of 
vegetative sprouts may remove a resource for pests 
that prefer to feed on young succulent tissue (e.g., 
green apple aphid and spirea aphid), but wound exu- 
date from pruning cuts may offer direct nutrient bene- 
fits to pests like wooly apple aphid. Summer pruning 
may also trigger a change in the level of tree nutrients 
or defense compounds, and subsequently influence 
phytophagous arthropod populations this way. 

Two pruning experiments were conducted in 1988 
on M.7 Mcintosh trees at the University of Massachu- 
setts Horticultural Research Center, Belchertown. These 
studies were undertaken initially to determine the 
effect of summer pruning on fruit production. How- 
ever, data on fruit yield and quality will be reported in 
a future issue of Fruit Notes. Here, only data on arthro- 
pod pest and predator levels are reported. 

On August 26, 10 fruit cluster leaves and 10 non- 
cluster leaves were sampled from the interior of each 
tree at about head height. Within a cluster, the third to 
the fifth leaf out was sampled. Non-cluster leaves were 
picked from the interior part of a branch (not the 
branch terminal) and were equivalent in size to cluster 
leaves. The underside midrib area of each leaf was 
evaluated for presence or abscence of European red 
mites (ERM) and two-spotted spider mites (TSSM), 
and also for presence or absence of the predatory mites 



Amblyseius fallacis (AF) and Zetzelia mali (ZM). These 
leaves were also evaluated for white apple leafhopper 
(WALH) damage and apple blotch leafminer (ABLM) 
damage (sap and tissue feeders). In addition, 10 prun- 
ing cuts on the tree interior were sampled for the 
presence of wooly apple aphid (WAA). In control (non- 
pruned) trees, 10 pruning cuts from the previous year 
were examined. 

Experiment 1 was aimed at determining benefits of 
summer pruning at various times after June. Three 
rows of trees were randomly divided to accommodate 8 
replications of 6 treatments. The treatments consisted 
of trees pruned on July 1, July 15, August 1, August 15, 
and September 1 and a control tree that was not 
pruned. 

Experiment 2 was conducted to determine effects 
of summer pruning in combination with stop-drop 
applications. In the same rows as Experiment 1, addi- 
tional trees were chosen to provide 7 replications of 
these treatments: 1) summer pruning, 2) summer 
pruning plus NAA, 3) summer pruning plus Alar, 4) 
NAA, 5) Alar, and 6) a control that received no treat- 
ment. In this experiment all summer pruning occurred 
on August 1 . Alar was applied on July 15. NAA was ap- 
plied on September 18, after the first harvest (Septem- 
ber 16). Note that NAA was applied after the arthropod 
sample date. Data from treatments 2 and 4 thus will be 
excluded. 

Results from both experiments revealed that popu- 
lation levels of WALH, TSSM, and the predator mites 
ZM and AF were extremely low and not significantly 
different among treatments. Low populations of ZM 
and AF are typical of orchards where predator-harsh 
pesticides have been used. Populations of TSSM are 
often low in situations where ERM may have outcom- 
peted them. 

Population levels of other insects and mites sur- 
veyed in Experiment 1 varied among treatments (Table 
1). On most sampling dates, more ERM were found on 
fruit cluster leaves than on non-cluster leaves. There 
were no trends that may have suggested that pruning 



Fruit Notes, Spring, 1989 



Table 1. Effects of summer pruning of Mcintosh 


apple trees on 


European red 


mite (ERM) and apple 


blotch leafminer (ABLM) populations on 


leaves, and on 


wooly apple aphid (WAA) populations 


around pruning cuts. 




Percent leaves 


Number of ABLM 




with ERM 


mines/leaf 












Percent cuts 
with WAA 


I runing 

Date Cluster 


Non-cluster 


Cluster 


Non-cluster 


Control 71 


69 


1.0 


0.66 


10 


July 1 67 


61 


0.63 


0.30 


9 


July 15 74 


71 


0.75 


0.46 


14 


August 1 51 


71 


0.78 


0.69 


1 


August 15 70 


70 


0.70 


0.60 


3 


September 1 71 


64 


0.70 


0.53 


15 


1 



Table 2. Effects of summer 


pruning on August ] 


and of Alar application on European 


red mite (ERM) and appk 


blotch leafminer (ABLM) populations on 


leaves, and on 


wooly apple 


aphid (WAA) populations around 


pruning cuts. 






Percent leaves 


Number of ABLM 






with ERM 


mines/leaf 












Percent cuts 


Treatments 


Cluster 


Non-cluster Cluster Non-cluster 


with WAA 


Control 


27 


17 


0.44 0.31 


16 


Alar 


26 


26 


0.51 0.40 


11 


Summmer 










pruning 


34 


31 


0.40 0.41 


19 


Summer pruning 








+ Alar 


30 


29 


0.51 0.36 


16 


1 



date had any substantial impact on ERM abundance. 
Mines from ABLM likewise were more abundant on 
fruit cluster leaves than on non-cluster leaves. In this 
case, the fewest ABLM mines on both cluster and non- 
cluster leaves were found on trees pruned on July 1. 
Perhaps pruning on this date eliminated leaves that 
otherwise would have been utilzed by second genera- 
tion ABLM ovipositing at that time. The lowest WAA 
populations were found on trees pruned on August 1 
and August 15. Summer pruning on any date did not 
appear to lead to buildup of either ERM or ABLM 
compared with populations on non-pruned trees, al- 
tough WAA on trees pruned July 15 and September 1 
were slightly greater than populations on non-pruned 



trees. 

In Experiment 2 (Table 2), there were no apparent 
differences in the numbers of ERM, WAA, or ABLM 
mines among treatments. However, there did tend to 
be more ERM and more ABLM mines on cluster leaves 
than on non-cluster leaves. 

These data are preliminary and should be com- 
bined with results on fruit production to make sound 
decisions about summer pruning. While further re- 
search is needed to determine the influence of summer 
pruning on pest and predator populations throughout 
the summer, the results presented here do not suggest 
that summer pruning has a major impact on foliar pest 
populations. 



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Fruit Notes, Spring, 1989 



New Trap-capture Thresholds for Tarnished 
Plant Bug and European Apple Sawfly In 
Massachusetts Apple Orchards 

Kathleen Leahy, Ronald J. Prokopy, and William M. Coli 
Department of Entomology, University of Massachusetts 



IPM trap-capture thresholds for tarnished plant 
bug(TPB) and European apple sawfly (EAS) originally 
were developed in 1980. Changes in input costs and 
produce prices have reduced the reliability of these 
thresholds. In this article we are presenting new 
threshold values as well as a general format for estab- 
lishing a trap-capture threshold. With this format 
growers could use their own price and production 
figures to calculate appropriate thresholds and update 
them as their data change. 



The new trap capture thresholds are as 


follows: 


Fruit market 


TPB, silver tip to: 


EAS (all) 


Tight cluster Pink 


Wholesale 
Retail 


3.5 5.5 

5.4 7.7 


9.0 
9.0 


1 



The actual mechanics of how the new thresholds 
were determined can be seen in the Table 1. Clearly, a 
number of assumptions needed to be made about per- 
acre fruit production, types and costs of chemicals 
used, etc. Some of the assumptions used were: 

- 15 minutes to spray one acre 

- labor cost = $7/hr 

- equipment cost = $8.68/hr, developed from 
publications by New York agricultural 
economists, updated by W. R. Autio 

- use of an organophosphate insecticide 

- per-acre production = 500 bushels 

- average 80% Extra-Fancy packout 

- fruit values = $15/bu U. S. Extra Fancy, $9/bu 
U. S. Number 1, $7.50/bu Utility, $2/bu 
Processing 



In all cases, where a choice of assumptions was pos- 
sible, we used the more consei-vative figure. 

One obvious fact that emerged in calculating these 
new thresholds was that the intended market for the 
fruit made a difference in how much injury a giower 
could tolerate. A gi-ower selling fruit through a farm- 
stand, or who could otherwise market fruit graded less 
than U. S. Fancy, can afford more injuiy than a gi-ower 
for whom any fruit that does not meet the U.S. Fancy 
gi-ade will be priced as processing fruit. Thus, we found 
that wholesale growers need to be considerably more 
conservative in their pest management decision-mak- 
ing than retail gi-owers, a fact that probably will not 
surprise most growers. In response to this situation, 
we developed separate thresholds for the two situ- 
ations. 

Thus, we considered two possibilities for down- 
graded fruit: first, U. S. Extra Fancy downgraded to a 
mix of U. S. Number 1, Utility, and processing (20, 70, 
and 10 %, respectively, of those fruit downgraded); and 
second, U. S. Extra Fancy downgraded to processing 
only (100 % of those fi-uit downgraded). We also used 
data from a number of packout studies (e.g., Morin and 
Bahn, Fruit Notes 1981) showing that only about 10% 
of plant bug injury actually is downgraded at all, since 
it tends to occur in the calyx of the fruit, hidden from 
view. 

Mostly what these new thresholds demonstrate is 
that some gi-owers can tolerate more, and even a good 
deal more, tarnished plant bug injuiy than had previ- 
ously been assumed. In the case of sawfly, the tolerable 
threshold likewise is slightly higher. But we do not 
expect that growers will be able to save many sprays for 
sav^y, since a petal fall insecticide would usually be 
necessary for plum curculio or other insects even if 
sawfly were not a problem. In ceilain years when 
curculio adults begin attacking apples later than nor- 
mal (e.g., a week after petal fall), sawfly trap captures 
can indicate whether sawflies are sufficiently abun- 
dant to spray at petal fall or not. 



Fruit Notes, Spring, 1989 



Table 1 . Calcxilating the trap-capture thresholds for tarnished plant bug (TPB) and European apple 
sawfly (EAS) in retail and wholesale apple orchards. 

I. The "break-even" level of injury is calculated related to the cost of the injury and the 
cost of the treatment. 



E + L + C 



B = 



where: 



(P)P(F/100)[$XF-($NO)(NO/100)-($U)(U/100)-($P)(P/100)] 



B = "Break-even" proportion of injury 

E = Equipment cost per acre 

L = Labor costs per acre 

C = Chemical costs per acre 

P = Total production per acre 

XF = % U. S. Extra Fancy if no injun/ was to occur 

$XF = Value of 1 bushel of U. S. Extra Fancy grade fruit 

$NO = Value of 1 bushel of U. S. Number 1 grade fruit 

NO = % of injured fruit downgraded to U. S. Number 1 grade 

$U = Value of 1 bushel of Utility grade fruit 

U = % of injured fruit downgraded to Utility grade 

$P = Value of 1 bushel of Processing grade fruit 

P = % of injured fruit downgraded to Processing grade 

The following calculations were made with the assumptions used in this article. 

For TPB in a retail operation: 

B(retail-TPB) = 

$2.17 + $1.75 + $8.55 

(500 bu)(80%/100)[$15 - ($9)(20%/100) - ($7.50)(70%/100) - ($2)(10%/100)} 

= 0.004 = 0.4 % 



Fruit Notes, Spring, 1989 



Table 1 , continued. 

For TPB in a wholesale operation and EAS: 

$2.17 + $1.75 + $8.55 



B(wholesale-TPB) - B(EAS) = 

(500bu)(80%/100)[$15-($2)(100%/100)] 

= 0.0024 = 0.24 % 

II. Some damage will occur regardless of treatment. For TPB 0.05 % should be added 
to B, and for EAS 0.1 % should be added to B. 

T= B + A 

where: 

T = Total % injury 

A = % injury even with a well-timed insecticide treatment 

With the assumptions used in this article: 

T(retail-TPB) = 0.4% + 0.05% = 0.45% 

T(wholesale-TPB) = 0.24% + 0.05% = 0.29% 

T(EAS) = 0.24% + 0.1% - 0.34% 

III. A portion of the total TPB injury is not downgraded. Data suggest that only 10 % of 
the TPB injury actually is downgraded; whereas 100 % of the EAS injury is down 
graded. 

EIL = T/(D/100) 

where: 

EIL = Economic injury level 

D = % of injury actually downgraded 



10 Fruit Notes, Spring, 1989 



Table 1, continued. 

With the assumptions used in this article: 

EIL(retail-TPB) = 0.45%/(10%/100) = 4.5% 

EIL(wholesale-TPB) - 0.29%/(10%/100) = 2.9% 

EIL(EAS) = 0.34%/(100%/100) = 0.34% 

IV. The trap-capture threshold (TC) can be calculated from the EIL using relationships 
presented by Coll et al. (1 985) Agriculture, Ecosystems and the Environment 1 4:251 - 
265. 

TC(TPB-before tight cluster) = (EIL + 0.0774) /0.8507 
TC(TPB-before pink) = (EIL + 0.9981 )/0.71 07 

TC(EAS) = (EIL + 0.3438)/0.0757 

With the assumptions used in this article: 
TPB before tight cluster 

TC(retail) = (4.5 + 0. 077 4) /0. 8507 = 5.4 TPB/trap 

TC(wholesale) = (2.9 + 0.0774)/0.8507 = 3.5 TPB/trap 
TPB before pink 

TC (retail) = (4.5 + 0.998 1)/0.7 107 = 7.7 TPB/trap 

TC(wholesale) = (2.9 + 0.9981 )/0.71 07 = 5.5 TPB/trap 
EAS 

TC = (0.34 + 0. 3438) /0. 07 57 = 9.0 EAS/trap 



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Fruit Notes, Spring, 1989 1 1 



Diagnosing Leaf Injury Symptoms 

Karen I. Hauschild 

University of Massachusetts, West Springfield, MA 



Growers often are faced with individual trees or 
gi'oups of trees that show unusual leaf symptoms -- 
either color changes, shape or size differences, or in 
some situations, leaves "just don't look right." It is 
relatively easy to rule out insect and disease problems, 
but often it is much more difficult to diagnose nutri- 
tional or weather- related foliar damage. The purpose 
of this aiticle is to help gi'owers determine the cause of 
non-pest related foliar damage. 

Herbicide injuiy is often confused with, or hard to 
distinguish from, nutritional deficiency symptoms. 
The best clue to herbicide injuiy is your knowledge of 
application - how and when each herbicide was ap- 
plied. Proper sprayer calibration, attention to label 
directions, and attention to weather conditions when 
applying materials all will help to minimize herbicide 
damage. 

Common Herbicide Injuries and 
Their Symptoms 

Terbicil (Sinbar^*^) -- Injury results in pronounced 
differentiation of green and yellow areas of leaves. 
Leaves also may appear deformed. Leaf veins may be 
greener than normal. 

Dichlobenil (Casoron^"^) - Injuiy results in yellow- 
ing of the leaf margins. Leaves may be deformed. 

Diuron (Karmex^*^) - Injury is similar to calcium 
chloride injury and moisture stress. It is characterized 
by browning of leaf margins that eventually progi-esses 
throughout the leaf. 

Simazine (Princep^") - Injury develops as necrosis of 
the leaf margins, wdth a quick onset of necrosis of the 
entireleaf. Leaves also may appear blotchy. With more 
severe damage, leaves tear and veins become more 
pronounced. 

Weather-related Injuries 

Drought - Symptoms originate at leaf tips, and mar- 
gins then become necrotic. These symptoms usually 
follow a period of dry weather. 



Frost injury - Injury shows as a whitening of leaves. 
Leaves become parchment-like in appearance. Symp- 
toms are often confined to lower limbs. 

Nutritional Deficiency Symptoms 

Nitrogen (N) - The primaiy expression of deficiency 
is the yellowing of leaves. Leaves also may be tinged 
with red and the coloration may progi-ess to orange-red 
with time. Leaves also can be small and deformed and 
may abscise. 

Potassium (K) - Deficiency is most often a problem 
on young, fruiting trees. It starts as a loss of green color 
followed by a water-soaked appearance in the older 
leaves and progresses to leaf scorch. 

Magnesium (Mg) - Older leaves are affected first. 
Areas between leaf veins become yellow, and with time 
become necrotic. By late summer, shoots may defoli- 
ate, leaving tufts of green leaves at tips. 

Manganese (Mn) - Deficiency appears first on older 
leaves and is seen as fading of leaf margins. This fading 
is inward progi-essing toward the leaf midrib. Green 
veins may be sharply defined with white-yellow colora- 
tion between them. 

Zinc (Zn) - Deficiency may appear as rosettes of leaves 
in early spring (dense cluster of narrow leaves above, or 
at the end of, an othei-wise leafless twig). It also may 
show as short, lateral spurs, or marginal intei-veinal 
yellowing. 

Although it often is difficult to diagnose the cause 
of leaf injuries, knowledge of local weather patterns 
and accurate, up-to-date herbicide and fertilizer appli- 
cation records will help you make an accurate diagno- 
sis. Where one or more nutritional deficiencies is 
suspected, foliar tissue analysis can confirm your diag- 
nosis. When leaf symptoms occur, the above symptom 
descriptions should help you determine the tree's par- 
ticular problem. Remember, however, that more than 
one problem could be present, and that often one 
symptom can mask another. 



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12 



Fruit Notes, Spring, 1989 



Integrated Pest Management for 
Commercial Strawberry Growers 
In Massachusetts 



Sonia G. Schloemann and Daniel R. Cooley 

Department of Plant Pathology, University of Massachusetts 



The strawberry IPM program began in 1987 with 4 
cooperating growers. This number expanded to 14 in 
1988. This e.xpansion provided a better sample of 
grower practices and improved overall contact with 
Massachusetts growers. We also expanded the geo- 
graphic base of the progi'am to include a wider area of 
the state. Cooperating growers were chosen from 
among those who had responded positively to a ques- 
tion on the 1 987 gi'ower survey asking if they would like 
to become involved in the IPM program. 

Fieldswere scouted for tarnished plant bug, straw- 
beny bud weevil (clipper), and two-spotted mite. 
Recommendations were also made for Botiytis gray 
mold management. The sampling methods used for 
monitoring insect populations were those generally 
used by other IPM programs in New York and New 
England. Relative yield impact due to pest injuiy was 
monitored and comparisons were made between areas 
under IPM management and ones under conventional 
management. 

Tarnished Plant Bug 

For this insect, two scouting methods were com- 
bined. It has been asserted that the immature stages 
are the form of this insect that cause economic injury to 
strawberries (Schaefers, 1980). Adults are present, 
but in lesser numbers than nymphs, and are consid- 
ered less of a threat. Nymphs are said to hatch around 
bloom, the gi-owth stage most susceptible to TPB in- 
juiy. White sticky traps were used for an indication of 
adult activity (Coli, 1985). Thresholds are not available 
for this method, because trap catches do not correlate 
with resulting injury levels. However, traps can deter- 
mine when adult tarnished plant bugs become active. 
We are developing a database of trap catches over 
several years to be used to develope thresholds. The 
main sampling method used for making management 
recommendations has been to assess nymph popula- 
tions. This sampling is done by shaking flower trusses 
and counting the number of nymphs that fall out. A 
threshold number of 1 nymph per 25 flower trusses 
was developed in New York (Schaefers, 1980) and has 



been used by our program for two years. Additional 
information suggests that the threshold perhaps can be 
raised substantially to 1 nymph per flower truss 
(Mailloux and Bostanian, 1988). 

The situation is somewhat confounded by reports 
that suggest that both nymphs and adults are causing 
economic injuiy to strawberries in Massachusetts. 
Adult insects cause much damage to strawberiy pro- 
duction in Maine and New Hampshire, but are consid- 
ered to be of little consequence in New York. New York 
researchers consider nymphs to be the primaiy prob- 
lem. Massachusetts may be at the inteiface of two 
ecological regions, which suggests the need for further 
research. 

Among our cooperating growers the average 
number of insecticide applications for tarnished plant 
bug control in 1987 was 1.8 sprays per season. Under 
IPM practices, these same growers made 0.9 insecticide 
applications in 1988, a 50 % savings. This level can also 
be compared to non-IPM areas on the same farms this 
year where 1.4 insecticide applications were made. 
Here, IPM recommendations resulted in a 35% savings 
(Schloemann and Cooley, 1988). No significant differ- 
ences in injuiy to fruit were obsei-ved. 

Strawberry Bud Weevil 

Strawberry bud weevil is an insect which destroys 
individual buds before the strawberries can form. This 
pest is of gi'eat consequence in mid-western states and 
is becoming of greater concern in New England. Of the 
14 cooperating growers in 1988, 11 sampled positive for 
the presence of strawberiy bud weevil (clipper). Only 
4 of these gi-owers had levels of clipper high enough for 
concern, though 8 typically spray for them. The sam- 
pling method for clipper involved counting the number 
of clipped buds per foot of row. A threshold of 0.6 
clipped buds per foot was used (Schaefers, 1972). The 
problem with this method is that it evaluates damage 
after the fact. Work has begun in New York to evaluate 
the efficacy of boll weevil traps for clipper. This trap- 
ping may be a valuable innovation for the future. 



Fruit Notes, Spring, 1989 



13 



Two-spotted Mite 

Two-spotted mites provided a very interesting case 
for the strawberry IPM program this year. Late in the 
1987 season, strawberry growers saw the removal of 
cyhexetin (Plictran^'^) from use for mite control. This 
loss left very few materials available to growers. Mite 
infestations were early and heavy in some locations in 
1988. Ordinarily, high mite levels do not occur before 
mid-June. This time is approaching hai-vest which 
makes spraying difficult due to harvest intei'val restric- 
tions. This year, with such high levels early in the 
season, gi-owers were concerned. The use of predators 
for the control of two-spotted mites has been studied 
(Croft et al., 1976; Penman et al., 1979; Waite, 1988). 
These predators feed on all stages of two-spotted mite, 
disperse rapidly in strawberry fields, and are indige- 
nous to the Northeast. In many cases, the natural 



Table 1. Two-spotted spider mite populations per 
strawberiy leaf at first occurrence of the predator 
mite Am6/ys/ews/a//ads, and for 3 weeks following 
its appearance. No miticide applications were 
made. 

Average TSM population per leaf 

Grower Weeks after 1st occurrence of A fallacis 
site 12 3 



1 
2 
3 
4 
5 
6 
7 
8 

Mean 



0.5 


0.5 


2.0 


2.2 


0.9 


0.4 


1.5 


0.4 


3.2 


1.1 


6.5 


0.3 


33.8 


12.5 


30.0 


1.6 


16.2 


2.5 


1.0 


0.2 


5.3 


21.6 


13.6 


1.8 


0.4 


1.0 


27.5 


0.2 


1.9 


13.0 


7.5 


0.2 



7.8 



6.6 



11.2 



0.9 



populations are sufficient and appeared to be effective 
in keeping two-spotted mite population levels low. 
Releases of artificially reared populations can also be 
made in locations where the natural populations are 
insufficient for control. A local business, Biokon, has 
emerged for the distribution of the predator Ambly- 
sieus fallacis. In cooperation with Biokon, the straw- 
berry IPM program monitored population levels of pest 
and predator mites prior to and after releases of the 
predators were made. The results were impressive. In 
most cases the predators "cleaned up" the two-spotted 
mites within 2 to 3 weeks, a result difficult to achieve 



Table 2. Mean numbers of fungicide applications 
and percent injured fruit at harvest for IPM and 
non-IPM blocks in 1988. 

Number of fungicide Injured fruit 
Treatment applications at harvest (%) 



IPM 
Non-IPM 



1.1 b- 
3.8 a 



5.6 a 
6.3 a 



•Means within columns not followed by the same 
letter are significantly different at odds of 20 to 1. 



with miticide applications. Data in Table 1 illustrate 
these results. 

Botrytis Gray Mold 

Strawberry growers make more pesticide applica- 
tions to control Botrytis cinerca, the fungus which 
causes gray mold, than for any other single problem in 
commercial strawberiy production in Massachusetts 
(Schloemann and Cooley, 1987). In 1987 Massachu- 
setts growers applied an average of 5.6 fungicide 
sprays, ranging from to 15. These applications cost 
growers about $140 per acre. Studies have shown that 
the most susceptible gi-owth stage for the infection of 
Botrytis is bloom, when the fungus infects the tender 
blossom tissue (Devaux, 1987; Grove etal., 1985). The 
infection remains latent until conditions of fruit devel- 
opment and favorable weather conditions coincide. 
Therefore, the IPM program in Massachusetts targets 
bloom to prevent infection. Many growers have had 
great success with this program of bloom sprays and 
have saved several spray applications later in the sea- 
son. Table 2 shows that under IPM recommendations 
in 1988, cooperating growers made an average of 1.1 
fungicide applications this year, compared to 3.8 in 
non-IPM blocks on the same farms, a 70% savings. 
Incidence of Botrytis in IPM vs. non-IPM fields was not 
significantly different. However, disease pressure was 
light this year. The progi-am's goal is to keep Botiylis 
sprays to an average of 3 or less. 

Inoculum causing blossom infections comes from 
ovei^wintering Botiytis in the live leaf tissue of straw- 
berries protected under the mulch (Braun and Sutton, 
1986; Braun and Sutton, 1987; Sutton and Braun, 
1987; Sutton, 1988). These leaves are infected in the 
fall. As they senesce in the spring, they produce spores. 
Efforts are undei-way to develop ways to inhibit the 
ability of Botrytis spores to penetrate the leaf surface 
successfully in the fall, thereby reducing the initial 



14 



Fruit Notes, Spring, 1989 



inoculum available for infection in the spring. This 
information is being incorporated into research efforts 
to be conducted in the future. 

Applied Studies 

The strawberry IPM program has secured 2 acres 
of land at the University research farm in South Deer- 
field for applied studies of pest management practices. 
Currently, studies of fumigation materials at different 
rates and non-fumigant cultural practices are in prog- 
ress. There is little doubt that fumigation provides 
tremendous production benefits. However, its eco- 
nomic and ecological costs are generally high. Alterna- 
tively, certain cover corps have allelopathic qualities 
which reduce pathogens, nematodes, and the viability 
of weed seeds. They might also have some direct 
economic value to the grower, as with Sude.x (a Sudan 
X sorghum hybrid which is now used by some growers 
as winter mulch) or pumpkins (which have been stud- 
ied for their allelopathic qualities related to black root 
rot control in strawberries). This work illustrates the 
value of cultural practices in IPM systems. Additional 
studies for improved and innovative management of 
Botiytis gray mold, tarnished plant bug, and two- 
spotted spider mites are planned for 1989. 

References 

Braun, P. G., and J. C. Sutton. 1986. Management of 
strawberiy gray mould with fungicides targeted 
against inoculum in crop residue. 19S6 British Crop 
Protection Conference-Pests and Diseases. 8A-4. 915- 
921. 

Braun, P. G. and J. C. Sutton. 1987. Inoculum sources 
of Botrytis cinerea in fruit rot of strawberries in On- 
tario. Canadian J. Plant Path. 9(l):l-5. 

Coli, W. M., T. A. Green, T. A. Hosmer, and R. J. 
Prokopy. 1985. Use of visual traps for monitoring 
insect pests in the Massachusetts 1PM program. Agric. 
Ecosystems Environ. 14:251-265. 

Croft, B. A., A. W. A. Brown, and S. A. Hoying. 1976. 



Organophosphorus-resistance and its inheritance in 
the predacious mite Amblyseius fallacis. J. Econ. 
Entomol. 69:64-68. 

Devaux, A. 1978. Etude epidemiologique gruse des 
fraises et essais de lutte. Phytoprotection 59:19-27. 

Grove G. G., L. V. Madden, M. A. Ellis and A. F. 
Schmitthenner. 1985. Influence of temperature and 
wetness duration of infection of immature strawberry 
fruit by Borry'is cinerea. Phytopath. 75:165-169. 

Mailloux, G. and N. J. Bostanian. 1988. Economic 
injury level model for tarnished plant bug Lygus lline- 
olaris in strawberry fields. Env. Ent. 17:581-585. 

Penman, D. R., C. H. Wearing, E. CoUyer, and W. P. 
Thomas. 1979. The role of insecticide resistant 
phytoseiids in integrated mite control in New Zealand. 
Proc. 5th Int. Cong. Acarol. 5:59-71. 

Schaefers, G. A. 1972. Pest management systems for 
strawberry insects. CRC Handbook of Pest Manage- 
ment in Agriculture. Vol 111. Pimentel, ed. 

Schaefers, G. A. 1980. Yield effects of tarnished plant 
bug feeding on June-bearing strawberries in New York 
state. J. Econ. Ent. 73:721-725. 

Schloemann, S. G. and D. R. Cooley. 1987. Strawberiy 
IPM survey. 1987 Strawberry IPM Program Report. 

Schloemann, S. G. and D. R. Cooley. 1988. 1988 
Strawberry IPM Program Report. 

Sutton, J. C. 1988. Alternative methods for managing 
gray mold fruit rot of strawberries. Proc. 1988 Annu. 
Mtg., North American Strawberry Growers Assn.:120- 
129. 

Sutton, J. C. and R. G. Braun. 1987. New methods for 
controlling gray mould fruit rot {Botrytis cinerea) on 
strawberries. Proc. Ontario Hort. Crop Conf. 

Waite, G. K. 1988. Integrated Control of Tetranychus 
urticae in strawberries in South-East Queensland. 
Experimental & Applied Acarology 5:23-32. 



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Fruit Notes, Spring, 1989 



15 



From the editors: 

The following is the first in a series of reprinted articles from Fruit 
Notes of 50 years ago. This discussion by Professor Van Meter was first 
published in the February, 1939 issue. 



Planting Orchards in Massachusetts 



R. A. Van Meter 

Department of Pomology, University of Massachusetts 



The average rainfall in Massachusetts is about 43 
inches. This is more than the impoilant competing 
apple regions get. We get our heaviest precipitation in 
July and August when we need it most. Our climate 
gives a finish to apples that has long been famous, and 
its very severity holds insects like codling moth in 
check to such an extent that we have less trouble with 
them than any important competing section. 

In the past 10 years Virginia has averaged about 
45% of a crop each year. New York has averaged 53%, 
New England 63%, and the Northwest about 70%. The 
Northwest stands highest in average % of a crop and 
New England comes next. The dependable cropping of 
New England orchards is a real advantage. We are 
rapidly becoming a one-variety section and that is a 
disadvantage. Mcintosh is the most popular apple on 
the market and we would not trade it for any or all the 
others grown elsewhere, but we do need a good, high 
quality variety to grow with it. Mcintosh probably is 
the most difficult apple to handle that is grown any- 
where and we still have much to learn about placing it 
on the market in good condition. 

We have some excellent orchard sites and soils, 
many of which are not now utilized for orcharding. 
Recent studies of the relation of subsoils to root devel- 
opment have added much to our knowledge of what 
soils to select. 

Here in the Northeast we have a densely populated 
area characterized by a high concentration of wealth. 
This makes the best market on the continent. Its 
nearness makes marketing costs veiy low and affords 



advantages that many sections can never offset. This is 
all reflected in the average per bushel price received by 
Massachusetts growers. Table 1 will make this clear. 



Table 1. Average farm 


price paid for apples. 


1934 


1935 1936 1937 


Massachusetts $1.26 
Virginia, etc. 0.89 
Northwest 0.73 
United States 0.88 


$1.02 $1.35 $0.90 
0.72 0.99 0.60 
0.60 0.96 0.69 
0.71 1.05 0.70 


1 



The decline in the per capita consumption of apples 
is not necessarily a calamity for the apple grower. The 
per capita consumption is arrived at by dividing the 
total crop (150,000,000 bu.) by the population 
(125,000,000) to get the average consumed by each 
individual (1 1/5 bu.). This is lower than it was a few 
years ago--not because people refuse to eat apples for 
they eat all you grow, but because fewer apples are 
produced. Why are fewer apples produced? Cold 
winters have destroyed millions of apples trees; in- 
creasing difficulties in controlling pests have driven 
many thousands of small orchards out of business, and 
commercial orchards have not been planted fast 
enough to take up the slack. Prices have not been high 
enough to encourage large-scale planting-that is 
where the decline in consumption operates. 



16 



Fruit Notes, Spring, 1989 



People have not turned away from apples. In the 
last 5 years they have eaten 3 times as many apples as 
oranges and 6 times as many apples as grapefruit. If we 
do plant more orchards in New England we shall not 
wreck the market, for prices are affected by the supply 
of all fruits in the country. We grow but about 5% of the 
total apple crop. The last census showed about 
6,000,000 apple trees in New England. If all these trees 



lived 50 years we would have to plant 120,000 more 
trees per year in New England in order to maintain the 
number of trees. We haven't been doing that. Theman 
who knows his business should plant in the right places 
making a careful choice of varieties and plant acreage 
enough to give him a satisfactoiy living. There is still 
a chance for apple glowing in New England as a sound 
conservative industry. 



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Fruit Notes, Spring, 1989 



17 



COOPERATIVE EXTENSION 

U. S. DEPARTMENT OF AGRICULTURE 

UNIVERSITY OF MASSACHUSETTS 

AMHERST. MASSACHUSETTS 01003 0099 



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Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

University of Massachusetts Cooperative Extension, 

United States Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R, Autio and William J. Bramlage 



ISSN 0427-6906 






c 



7% >/5 




JUL 24 1989 



bClENCES UBRARY 

Volume 54, Number 3 
SUMMER ISSUE, 1989 

Table of Contents 



A Critical Time for Change 

Storage of Marshall Mcintosh: Some Cautions for 1989 

Some Experience with Use of A Hollow-fiber 
System for CA-atmosphere Generation 

Seed Number in Apples Can Affect Calcium 
Accumulation and Keeping Quality 

Items from Here and There 



Fruit Notes 

Publication Information: 

Fruit Notes (ISSN 0427-6906) is published the first day of January, 
April, July, and October by the Department of Plant & Soil Sciences, 
University of Massachusetts. 



The costs of subscriptions to Fruit Notes are $4.00 for United States 
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tion begins January 1 and ends December 31. Some back issues are 
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addresses). Payments must be in United States currency and should 
be made to the University of Massachusetts. 



Correspondence should be sent to: 

Fruit Notes 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

University of Massachusetts 

Amherst, MA 01003 



COOPERATIVE EXTENSION POUCY: 

All chemical uses suggested in this publication are contingent upon continued registration. Thesechemicals should be 
used in accordance with federal and state laws and regulations. Growers are urged to be familiarwith all current state 
regulations. Where trade names are used for identification, no company endorsement or product discrimination is 
intended. The University of Massachusetts makes no warranty or guarantee of any lund, expressed or implied, 
concerning the use of these products. USER ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY 
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May S and June 30, 1 91 4. The University of Massachusetts Cooperative Extension offers equal opportunity in pro-ams and 
employment. 



A Critical Time for Change 



Duane W. Greene and Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 



Renewed adverse publicity has increased the like- 
lihood that Alar^** will not be available for orchard use 
in the future. Even if results of current tests show that 
Alar is a safe chemical, registration may be cancelled 
because of public pressure. The loss of Alar will influ- 
ence growers of Mcintosh and Stayman most, so these 
growers must not waste time in making the long-term 
decisions required to cope with growing apples without 
Alar. In a previous Fruits Notes article [54(2): 1-3] a 
number of options were put forth as alternatives to 
using Alar. The option that we will discuss here is the 
replacement of Mcintosh with different cultivars. 

There are many new, excellent-quality apple culti- 
vars now available, and many others are in the early 
stages of evaluation. The loss of Alar may be ablessing 
in disguise since there is now incentive to plant new 
and better-tasting cultivars. Selection of the cultivars 
to plant may be the most important management 
decision growers will make in the 1990's. Consistent 
and sustained increased per capita consumption of 
apples will not occur with continued planting of Mcin- 
tosh, Delicious, and Golden Delicious. Itwill only occur 
when we provide consumers with a wider choice of 
better-tasting apples that have a longer shelf life than 
is presently available. In this article we will describe 
the most viable alternatives to growing Mcintosh. 

Cultivars of Proven Superior Quality 

Where New England Growers May 

Have a Competitive Advantage 

Gala 

Gala is an apple cultivar introduced in New Zeal- 
and in 1962 by Dr. Donald McKenzie. We previously 
reported that this cultivar showed promise in New 
England [Fruit Notes 51(1):12-14]. The planting of 
Gala is no longer a gamble but a good business decision. 
It is being planted extensively in the Pacific Northwest 
and in many other areas in the country. It is estimated 
that nearly 25% of all apple trees planted in Washing- 
ton in 1990 will be Gala. In Massachusetts the fruit 
characteristics and storage potential of Gala were 
evaluated and compared to Mcintosh in 1988. Taste 
panelists consistently preferred Gala over Mcintosh. 

Gala is precocious and has shown early, heavy 



production. Trees at the University of Massachusetts 
Horticultural Research Center (Belchertown) on M.26 
yielded over 8 bu/tree in their 7"" leaf. Based on a 12- 
X 22-foot plant spacing there was a potential yield of 
1386 bu/acre in the 7^ leaf with a cumulative yield of 
about 3150 bu/acre. Gala is a "grower-friendly" tree 
with few cultural problems. Limb spreading is proba- 
bly not necessaiy. However, thinning is necessaiy 
since Gala fruit size is not large, but trees have not had 
any apparent tendency toward biennial bearing. 

There are several red-coloring strains of Gala 
available, and they are described below. Replicated 
strain trials were established in 1988 at the Horticul- 
tural Research Center and at Honeypot Hill Orchard 
(Stowe, MA). We will be reporting on these studies as 
soon as the trees come into production. 

Kidd'sD-8 . This strain is the original one released 
in New Zealand in 1962. Based on grower comments 
from other parts of the country, the flavor of this strain 
may be better than that of other red-coloring strains. 
Kidd's D-8 colors well in New England. In our 1988 
trials it developed red color on up to 80% of the surface. 
Unlike other cultivars, the nonred portion of Gala 
turns from green to yellow and finally to a very attrac- 
tive orange-yellow color, providing a striking feature 
for customer identification. Based on its appearance 
from Australia, Italy, and other portions of the USA, we 
believe that New England may produce the reddest and 
most attractive Kidd's D-8 Gala. We may have a 
distinct advantage in grovdng this strain. 

Royal Gala . This strain is the most widely planted, 
red-coloring strain of Gala. We fruited Royal Gala at 
the Horticultural Research Center in 1988. It has a 
distinct red stripe and is much redder than Kidd's D-8. 
The yellow-orange background color is lacking on this 
strain. Only time will tell what strain the consumer or 
marketing chain buyers will prefer. In our estimation 
the quality and taste of Royal Gala was at least compa- 
rable to that of Kidd's D-8 in 1988. 

Regal Gala . This strain is ablush type. It has been 
suggested, but not confirmed, that Regal Gala is more 
vigorous than Kidd's D-8 and may have superior color, 
larger fruit size, better flavor, and less firm fruit [Good 
Fruit Grower 40(7):7, 1989]. 

Imperial Gala . This striped strain is veiy similar to 
Royal Gala in fruit appearance. 



Fruit Notes, Summer, 1989 



Scarlet Gala . This strain produces a striped red 
fruit that may have better flavor than other red-color- 
ing strains. 

Spur Gala-Go-Red . This striped strain is the only 
spur-type Gala that has been identified. It is reported 
that Spur-Gala-Go-Red may produce larger, earlier- 
coloring, and brighter fruit than Royal Gala. This 
strain is not included in our trial but it is on order for 
delivery in 1990. 

Galaxy . It is a well-colored, solid-blush strain with 
a dark overstripe. Trees of this strain are not presently 
available. 

Jonagold 

This cultivar was released in 1 968 by the New York 
Agricultural Experiment Station in Geneva and is a 
cross between Golden Delicious and Jonathan. It has 
become very popular in Europe, especially in Belgium 
and Holland. Jonagold consistently receives high rat- 
ings for flavor. Last year Jonagold was the best tasting 
(except maybe for Gala) of all apples evaluated at the 
Horticultural Research Center. However, it may not 
have a long storage life. By the end of November acid 
levels had declined to the point where the taste was 
bland. Previous to that point, it was a superior and 
outstanding apple. 

Jonagold is a large yellow apple with a red blush or 
cheek. It requires at least as much if not more direct 
sunlight for red color to develop than Mcintosh. It is 
reported to ripen with Golden Delicious. We feel that 
it should have been harvested between October 4 and 
8 at the Horticultural Research Center. It is a triploid, 
so the trees are vigorous and cannot be used as polliniz- 
ers for other cultivars. There are many red-coloring 
strains of Jonagold, but these have not been evaluated 
extensively. 

There was intense interest in Jonagold in the 
Pacific Northwest until recently. However, two abnor- 
mally warm growing seasons exposed the susceptibil- 
ity of Jonagold to sunscald and reduced fruit quality. 
Consequently, Jonagold probably will be grown only in 
the cooler areas in the Northwest. The cool nights and 
sunny days in September and early October, climatic 
conditions which make New England an ideal place to 
grow Mcintosh, may also make New England the best 
place in the United States to grow Jonagold. The 
quality of this apple is excellent at harvest. The biggest 
question about Jonagold is how long can it be kept in 
storage before becoming bland and unappealing. 

A number of red-coloring strains of Jonagold have 
been identified, but few are presently available. We 
will attempt to keep growers in New England updated 
as these strains become available and reliable informa- 
tion is generated. 



Cultivars That Show Considerable 

Promise That Are Worthy of at Least 

Limited Planting 

Red Fuji 

We reported in an earlier article [Fruit Notes 
54(1):10] on the Red Fuji apples grown at the Horticul- 
tural Research Center. We have observed some of 
these fruit periodically from regular storage. Of the 
apples that we grow, these fruit appear to maintain 
flavor and firmness in regular storage much longer 
than any other. Pressure tests made on March 28, 1989 
after 22 weeks in regular storage, revealed that flesh 
firmness averaged over 16 lbs. Fruit harvested with a 
green ground color averaged over 18 lbs and their 
flavor was still very good. Fruit that were hai-vested 
with a yellowish-green giound color were somewhat 
bland and flesh firmness averaged about 14.5 lbs. 

This cultivar is being planted extensively in Cali- 
fornia and the Pacific Northwest. Fuji normally has a 
red or pink cheek on a greenish yellow ground color. 
Even the red-coloring strains do not develop the in- 
tense red color characteristic of red-coloring strains of 
other apple cultivars. However, growers in the North- 
east may have an advantage growing it since red color 
and desirable acid levels should develop more in our cli- 
mate. In 1988 it ripened at about the same time as 
Rome Beauty. It is a vigorous tree and we feel that it 
should be grown on rootstocks no more vigorous than 
M.26. 

There are several red-coloring strains available but 
all are largely untested in this country. We currently 
have 4 strains of Red Fuji under evaluation at the 
Horticultural Research Center. 

Liberty 

Of the disease-resistant cultivars available, Lib- 
erty is clearly the one with the highest fruit quality. 
However, Liberty should not be considered as a spe- 
cialty cultivar to be gi-own only in situations where no 
fungicides are used. Liberty is an apple that should be 
grown on its own merits. In taste tests conducted in 
Oregon and Washington and reported by Bob Stebbins 
at the most recent New England Fruit Meetings, Lib- 
erty was rated equal to or higher than Empire. It is a 
medium-sized, oblate fruit with red color over a yellow 
ground color, veiy similar in appearance to Empire. It 
is crisp and juicy, and qualities of one of its parents, 
Macoun, are quite apparent. It ripens with Empire. 
Trees are semivigorous and productive. It is likely that 
Liberty trees will require thinning to the same degree 
as Empire to obtain adequate fruit size. 



Fruit Notes, Summer, 1989 



Cultivars That May Be Worthy But 
Further Testing Is Required. 

Braebum 

Braeburn is a chance seedling that originated in 
New Zealand. It is firm, crisp, veiy juicy, sweet, and 
aromatic with light-green flesh and oval shape. Fruit 
are medium to large in size and green overlaid with 
red. Fruit are not attractive; however, the eating 
quality of this apple has been rated excellent. Probably 
the biggest question about Braeburn is whether or not 
our season is long enough to mature it. The maturity 
date of Braeburn has been compared to that of Granny 
Smith. However, the 1988 Apple Variety Progress 
report from Oregon State University by Bob Stebbins 
et al. indicates that Braeburn ripens a week later than 
Delicious and a week before Fuji. Braeburn appears to 
store well. The tree is moderately vigorous, precocious, 
and has a standard type grovvrth habit. It appears to be 
a "grower-friendly" tree [Pacific Northwest Fruit 
Tester's Association (PNFTA) Fact Sheet, James K. 
Ballard, 1 101 West Orchard Street, Selah, WA 98942]. 

Criterion 

This cultivar originated as a chance seedling in an 
orchard near Parker, Washington. Criterion is a yel- 
low apple with a shape similar to Delicious. Like 
Golden Dehcious, color is determined largely by the 
nitrogen status of the tree. It is a firm, sweet, aromatic 
apple with creamy flesh and excellent flavor. Criterion 
bruises easily. It is not prone to russet, and near 
harvest it develops a red cheek. Its storage potential is 
good. It is reported to ripens with Rome Beauty, 
although there are indications that it may not mature 
properly in western Washington and in British Colum- 
bia. It is a very vigorous tree which may not be as 
precocious as other cultivars (PNFTA Fact Sheet). 

Elstar 

This cultivar is one of the most attractive and 
promising of the new cultivars available. It is also one 
of the most heavily planted cultivars in Northern 
Europe. Elstar resulted from a cross between Golden 
Delicious and Ingrid Marie (a seedling of Cox's Orange 
Pippin) made at the Institute for Horticultural Plant 
Breeding at Wageningen, Holland. It is medium to 
large in size and round to conical in shape, with white 
flesh. It is a firm and somewhat-tart, yellow apple with 
a very attractive orange-red stripe that matures in late 
September. It may require a period of storage to 
develop acceptable flavor (PNFTA Fact Sheet). 



AceyMac 

Acey Mac is a selection from trees vegetatively 
propagated from a seedling tree discovered over 20 
years ago by Art Burrill in the Champlain VaUey of 
New York. It is very similar to Mcintosh in appearance, 
taste, shape, flesh color, and flesh texture. It is reported 
that Acey Mac is larger and firmer, has less preharvest 
drop, and ripens about 5 days later than Rogers Mcin- 
tosh. Red color development appears to be better than 
Rogers Mcintosh, and it may be comparable to 
Marshall Mcintosh. Acey Mac is a nonspur tree with 
growth and bearing characteristics similar to Mcin- 
tosh. Nine-year-old trees of Acey Mac are growing in 
the orchard of Bob Sodoma, Brockport, New York (Carl 
Perleberg, Columbia Basin Nursery, Quincy, WA and 
Dick Norton, Spencerport, NY). 

Buhr Mcintosh (Wafler Nurseries, Wolcott, NY) 
was originally propagated from the same tree as Acey 
Mac. We are unsure at this time if there are distin- 
guishable differences between Acey Mac and Buhr 
Mcintosh. 

Pioneer Mac 

Pioneer Mac is very promising, Mclntosh-type cul- 
tivar. It was discovered as an open pollinated seedling 
of Mcintosh at Ernest Greiner's farm in Marlboro, 
New York. It appears to have fruit characteristics very 
similar to those of Mcintosh, although it is reported to 
have better color than the Roger's strain. Taste and 
external appearance are close if not identical to Mcin- 
tosh. Preharvest drop does not appear to be a problem. 
It is a nonspur tree that may be less vigorous than 
Roger's Mcintosh (Phillip Baugher and Tom Callahan, 
Adams County Nursery, Inc., Aspers, PA). 

Cultivars of High Quality That May 

Have Local or National Market 

Acceptance 

Akane 

Akane ripens 7 to 10 days before the start of 
Mcintosh harvest. The fruit are firm, medium sized, 
and red with white, dense flesh. Fruit hang on the tree 
for an extended period of time without dropping or 
losing appreciable fruit quality. It has a distinctive 
spicy flavor. It appears to hold up better in storage than 
other late-summer apples. It has been reported to be 
somewhat resistant to scab. The largest fault that we 
find with Akane is that fruit set may be light. It is one 
of the shyest producers that we have at the Horticul- 
tural Research Center. 



Fnut Notes, Summer, 1989 



Paulared 

This cultivar is one of the most attractive and best 
tasting apples that ripens before Mcintosh. Fruit size, 
red color, and productivity have been very good at the 
Horticultural Research Center. It can be stored for 
several weeks without excessive softening. Since it is 
an attractive and early-coloring apple, the tendency is 
to harvest this cultivar too early, before its true flavor 
develops. Sufficient Paulareds should be planted so 
that they can be harvested at the appropriate time and 
sold with the fine flavor and quality that Paulared is 
capable of developing. 



Empire 

The popularity of this apple is increasing, espe- 
cially where it is difficult to color Mcintosh adequately. 
It is a high-quality, firm, red apple that stores excep- 
tionally well. In our estimation it is only rivaled by 
Mutsu for its ability to store in CA. It has not developed 
the popularity in New England that many thought that 
it would. Since it ripens between Mcintosh and Deli- 
cious, it is not always harvested at the proper time. 
Although its storage capability is exceptional, once 
removed from CA it appears to soften more rapidly 
than other cultivars. There does not appear to be the 
customer acceptance of a moderately soft Empire as 
there is with other cultivars with similar firmness. It 
may be difficult to obtain good fruit size in all areas, and 
it appears to be particularly difficult to size Empire in 
colder areas (a characteristic that it may have inherited 
from Delicious). 

Macoun 

The popularity of this old and difficult-to-grow 
apple appears to be increasing. The flavor and crisp- 
ness of Macoun is exceptional and makes this fruit a 
much sought after apple in the fall. Its many faults 
make it unpopular to grow. It may be very biennial, and 
hand thinning is frequently required. Red color may 
develop slowly, and preharvest drop may occur before 
adequate color. Fruit lose firmness rapidly in storage 
although they will store well in CA. This apple is not for 
everyone, but for those who can grow it, there is good 
customer demand. 

Mutsu (Crispin) 

The quality of Mutsu is among the highest of the 
apples that we can grow here in New England. It is a 
firm, juicy, and very large, yellowish-green apple that 
matures after Golden Delicious. It holds up very well in 
regular storage, but its regular storage potential is not 
exceptional. However, in CA storage fruit come out in 



almost identical conditions to that when they were 
placed in storage. Mutsu has not developed the popu- 
larity that its quality and CA potential warrant. It is 
susceptible to Pseudomonas or blister spot, and unless 
this problem is controlled, packout will be poor. We 
have found that 3 weekly sprays of Polyram'r", starting 
at bloom, control mostof the blister spot. Mutsu is also 
very susceptible to excess nitrogen. Mutsu is a yellow 
and not a green apple and frequently is picked too early. 
Like Granny Smith, if it is picked too early it v^rill have 
only mediocre flavor. For people who have roadside 
stands, this apple should attract considerable return 
business if grown properly and harvested at the time 
that will assure the quality that Mutsu is capable of 
developing. 

Melrose (and its red strains) 

This cultivar is the result of a Jonathan x Delicious 
cross. Fruit are large, firm, crisp, juicy, and red with a 
yellow background. It is a high quality apple that 
ripens with Golden Delicious and keeps well in storage. 
It is a very popular apple in Ohio. 



Idared 

Idared has been planted extensively in New York 
where it is suitable for fresh market or processing. It is 
a very easy tree to grow and maintain. It is a medium- 
sized red apple with good flavor. Idared ripens after 
Golden Delicious and it benefits from a period of stor- 
age following harvest. Although the quality of Idared is 
not as high as that of some of the other cultivars 
mentioned, its regular and CA storage potential are 
excellent. Long after other cultivars have lost firmness 
and flavor, Idared remains a good and saleable apple. 
People who grow this apple will have quality apples to 
sell from regular storage, prior to opening of CA stor- 
ages, and at the end of the apple marketing season. 

Growing of new, superior-quality apples will be 
successful only if the apples can be grown and sold at a 
profit high enough to stay in business. Growers who 
sell directly to the public through roadside stands have 
a distinct advantage since they can introduce to cus- 
tomers specific cultivars at the appropriate time to 
provide the customer with the best possible product. 

Growers who wholesale market their product will 
have a more difficult time but it is not impossible. 

1. Growers must insist and ensure that their product 
is sold at the proper stage of maturity. For example. 
Granny Smith is a high-quality apple that at proper 
maturity is yellowish green. Unfortunately, it is nearly 
impossible to buy a good Granny Smith in the grocery 



Fruit Notes, Summer, 1989 



stores, because all were harvested when still too green, 
before proper flavor developed. Idared has been sold 
for the past 2 seasons by local grocery chains in mid- 
September, fully 3 weeks before it should be harvested. 
It seem ludicrous to harvest an apple so early that you 
unjustifiably tarnish the name of that apple and also 
jeopardize sales of other apples. 

2. Grower groups may volunteer time to pass out 
apple samples in the grocery stores. Anyone who has 
shopped recently has been offered free samples of 
pizza, hotdogs, and cheese. Why not apples? 

3. In a recent address to the Washington State Horti- 
culture Society, Frieda Caplan, Chairman of the Board 
of Frieda's Finest Produce Specialties, Inc., made sev- 
eral suggestions to Washington State Growers to in- 
crease sales of their apples. She suggested that refrig- 
eration of apples in grocery stores should be the grow- 
ers' number one imperative. Taste, appearance, stor- 
age life, more rapid rotation, and increased sales would 
all be improved. It is time that we communicated to the 
public the conditions under which apples should be 
stored. 

4. There is a need for growers to become involved 
with cultivar testing. Jim Ballard, a prominent Wash- 



ington State pomologist and former Washington State 
University Elxtension specialist, has organized the 
Pacific Northwest Fruit Testers Association. This 
group is comprised of growers and nurserymen who 
have agreed to test and share results and observations 
of new apple cultivars with other members. Although 
the membership is changing rapidly, in December, 
1988, there were 180 members in 22 states and 12 
countries. This organization is providing an invaluable 
service to the industry by speeding up the testing 
process and providing the most current information on 
appropriate cultivars, especially those adapted to grow- 
ing conditions in the Pacific Northwest. Recent evalu- 
ations emphasize that environment plays a dominant 
role in determining the suitability of a cultivar for a 
particular location. Evaluations conducted in the Pa- 
cific Northwest provide a good first screening. How- 
ever, they provide only rough indications of suitability 
for the Northeast. 

Is it time to establish an evaluation organization in 
the Northeast? If you feel that this approach is appro- 
priate contact Duane Greene (413-545-4733) or Wesley 
Autio (413-545-2963). 



^* «f« ^« m9^ ^3 

*f» *f» •{• wj* wj* 



Fruit Notes, Summer, 1989 



storage of Marshall Mcintosh: 
Some Cautions for 1989 

Wesley R. Autio, William J. Bramlage, and William J. Lord 
Department of Plant & Soil Sciences, University of Massachusetts 



Marshall Mcintosh is presently the most widely 
planted strain of Mcintosh in the Northeast. In a 
previous issue of FruzYATofes [52(4): 1-5] we reported on 
tree, fniit, and storage characteristics of Marshall in 
comparison with 6 other strains. Marshall trees were 
similar in size to Morspur, Imperial, Macspur, Gatzke, 
and Rogers trees and yielded similar amounts. 
Marshall fruit colored earlier and to a higher degree 
than other strains, and Marshall fruit ripened 3 to 5 
days earlier than the other strains. Marshall trees 
produced relatively small fruit, but in most years they 
were not significantly smaller than Rogers fruit. 

We also evaluated the storage potential of Marshall 
and found no consistent differences between it and 
other strains with regard to softening or the develop- 
ment of storage disorders in refrigerated (32°F) or 
controlled atmosphere (CA) (37°F, 3% O2, 5% COg) 



storage. However, when commercial CA's were 
opened in 1988 a number of growers reported off- 
flavors and other injuries only with Marshall, which 
suggested that Marshall may be more sensitive to low 
O2 levels than other strains. To test these observations, 
we harvested 2 bushels of fruit from each of 8 Rogers 
and 8 Marshall trees (planted in 1979 in a replicated 
trial) . One bushel from each tree was kept in 3% O2 and 
5% COj, and the other bushel was kept at 2.25% O^ and 
5% COj. After 6 months of CA, 1 month of refrigerated 
storage, and 6 days at room temperature, the incidence 
of I0W-O2 injury was assessed. 

L0W-O2 injury can manifest itself in a number of 
ways including presence of off-flavors, purpling of the 
skin, and development of brown sunken patches on the 
surface. The most common symptom noted in this 
study was internal browning as shown in Figure 1. The 




Emit Notes, Spring, 1989 



35 



30 



25 



20 - 



15 



10 



Low oxygen injury (%) 



*** 




^H Roger* 
IZZ Marshal 




2.26% 3% 

Oxygen concentration 

Figure 2. The incidence of low-O^ injury in Marshall 
and Rogers Mcintosh fruit stored at 3% and 2.25 % O2 
after the 1988 harvest. 



flesh browning characteristic of I0W-O2 injury has a rim 
of normal, white tissue outside of the browned tissue 
and under the skin. With further development, this 
white rim disappears. 

Figure 2 shows the levels of low-Oj injury found in 
Marshall and Rogers fruit. Even at 3% Oj (the recom- 
mended level for CA storage of Mcintosh in New Eng- 
land) Marshall fruit developed some internal I0W-O2 
injury. At 2.25% O2, 32% of the Marshall fruit exhib- 
ited internal I0W-O2 injury, while only 4% of the Rogers 
fruit were damaged. This increased level of damage 



would represent a significant loss by a storage operator. 
Storage operators must monitor their O2 concentra- 
tions carefully and not allow O^ to drop below the 
recommended value if they are storing Marshall Mcin- 
tosh fruit. 

Because of its early coloring and ripening, 
Marshall Mcintosh will undoubtedly be of great value 
to the New England Mcintosh industry if Alar'''" is not 
used in the future. However, we stress that it is not safe 
to store Marshall fruit in CA with O2 concentrations 
below 3%. 



•X» «!• ai» •S* •S* 

*j» •]« *f» *{* ^* 



Fmit Notes, Summer, 1989 



Some Experience with Use of A 
l-lollow-fiber System for 
CA-atmosphere Generation 

William J. Bramlage and Joseph E. Sincuk 

Department of Plant & Soil Sciences, University of Massachusetts 



Controlled atmosphere (CA) storage of apples 
requires a method of reducing oxygen (Oj) concentra- 
tion in the storage atmosphere from that of air (2 1%) to 
the level desired for apple storage (usually 3% or less). 
Originally, the process used fruit respiration to "pull 
down" the O2, but at low storage temperatures this 
reduction usually requires 14 to 21 days or more. We 
now recognize that this length of time results in signifi- 
cant loss of fruit quality, and recommend that the at- 
mosphere be pulled down to 5% in no more than 3 days 
after sealing the room. This reduction cannot be done 
by fruit respiration alone. 

Rapid pull-down can be achieved by either displac- 
ing most of the storage air with nitrogen (N2), as tank 
gas or as liquid N2, or by using an external generator to 
create a I0W-O2 atmosphere that is piped into the room. 
Several types of generators were developed that mixed 



propane gas with air to produce carbon dioxide (CO2) 
and water either by open-flame burning or by catalytic 
chemical reaction. However, a series of storage explo- 
sions have made both storage operators and generator 
manufacturers wary about using these machines, and 
they rapidly are becoming obsolete. 

In New England, many CA storage operators re- 
cently have adopted use of liquid N, for CA pull-down, 
a practice that we have advocated (Proc. 92"'' Annu. 
Meet. Mass. Fruit Growers' Assoc. 1986:102-105), 
because it requires little capital investment and 
achieves a CA atmosphere rapidly and withoutbuildup 
of CO2, which would have to be removed. Liquid Nj 
also provides some cooling in the CA room. However, 
use of liquid N2 is not problem-free. Some freezing of 
fruit near the manifold outlets often occurs, and some 
storage operators have difficulty obtaining timely de- 



Jt' «r I--- ... ^ 



> V i 



*■ / 



Mfi* H2* He, H^, CX)2, O?. Ar, CO. Ns, CH4 

pl^$t*' "Slow" 

'"' ' Relative Permation Rates 



Stream 







S , •> ijf^O j- / •.' X. V '-. AC ..> 



Figure 1. Relative permeation rates for the Prism Alpha™ hollow-fiber system. 



Fruit Notes, Summer, 1989 



tnriched 

Oxygen 

Outlet 



Heater' 



Compressed 

Air 

intake 



w>«w»»wi»y»y»»wwN<»<ww»wi»y^wwy» jM >»w««w*ff 




i^phj 



Figure 2. A schematic representation of the hollow-fiber system used at the HRC. 



livery of liquid Nj. Also, cost of liquid N2 to different 
operators can vary considerably. 

We are interested, therefore, in the development of 
new types of atmosphere generators which remove the 
O2 from air in ways other than by using propane. Two 
types of these "air separator" generators now are avail- 
able commercially: "pressure-swing" units that re- 
move O2 by adsorption, and "hollow fiber" systems 
that remove it by diffusion. 

Pressure-swing adsorption binds O^, water, and 
some other gases onto a Carbon Molecular Sieve 
(CMS), leaving nearly-pure N^ that then enters the CA 
room. It is called "pressure-swing" because (a) the air 
entering the unit must be under high pressure, and (b) 
it consists of two columns of CMS, and alternates 
("swings") between them . . . the column not adsorbing 
gases is being regenerated so that it can be used again. 

The hollow-fiber membrane system is a unit filled 
with tiny plastic tubes, through which air is forced 
under pressure. The plastic is much more permeable 
to some gases, such as O^, CO2, water, and ethylene, 
than to others such as N2- Thus, as the air passes 
through the long tubes, the more permeable gases pass 
out through the plastic, and at the exit port the remain- 



ing gas is mostly N2, which then enters the CA storage. 

Through a lease agreement with Permea, Inc., a 
subsidiaiy of Monsanto Company and manufacturer of 
a hollow fiber system (Prism Alpha''""), we obtained a 
unit in September, 1987, for use at the University of 
Massachusetts Horticultural Research Center (HRC), 
Belchertown. This unit was designed to generate an 
atmosphere of 2 to 8% O2 and 98 to 92% N2 at a flow rate 
of 125 to 535 standard cu. ft. per hour, at a pressure of 
150 PSl. 

We immediately encountered a major problem. 
We had been assured that the 5 horsepower (HP) air 
compressor at the HRC would adequately power the 
unit, but it did not. Through aging it was inadequate, 
ran constantly, and overheated. As a result, we were 
unable to use the N2 generator to pull down our CA 
rooms. 

In January, 1988, we rented a 15 HP air compres- 
sor (which was oversized but available) so that we 
could use the Nj generator to regenerate a CA atmos- 
phere in a room that had been opened, partially emp- 
tied, and re-sealed. We were pleased with its operation, 
so in August, 1988, we purchased a new 5 HP genera- 
tor. Later, it was attached to operate in tandem with 



Fmil Notes, Summer, 1989 



the existing compressor to provide the pressure and 
volume of air needed to operator the N^ generator 
efficiently. 

In September, 1988, two 600-bushel CA rooms 
filled with Mcintosh apples were sealed. One was 
pulled down with liquid N2, and the other one was 
pulled down with the Nj generator. With liquid Nj the 
room was at 3% O2 in 1 hour. With the generator, the 
other room reached 5% O^ in 26 hours, although at that 
time the unit was being powered by only the new air 
compressor. 

After the two air compressors were operating to- 
gether, the Nj generator was used to pull down a 2500- 
bushel CA room filled with a mixture of "hard" culti- 
vars. The generator pulled the room down to 13% O^ in 
6 hours, and to 3% O^ in a total of 30 hours. 

At various times, the generator was used to purge 
O, from the storage atmosphere, to observe its opera- 
tion. For example, at one point it reduced O2 from 3.7% 
to 3.4% in 4 hours. The unit is effective for scrubbing 
COj, since COj diffuses rapidly through the plastic 
tubes, but in our system we maintain constant CO^ 
levels by adjusting continual flow through lime boxes, 
so we did not use the generator for COj scrubbing. 

In January, 1989, the 2500-bu room was opened, 
800 bushels were removed, the room was resealed, and 
the generator was used to pull down O^. In this partly 
empty room, the unit required 24 hours to reduce O^ to 
11%, and a total of 48 hours to reduce it to 7%. It then 
took an additional 48 hours to reach 3% O2. 

The hollow-fiber N^ generator exhibited a number 
of attractive features during these operations. Once 
the operator becomes familiar with its operation, the 
unit requires Uttle "tinkering" and does not have to be 
watched, so the operator is free to attend to other 



duties. The unit has no moving parts, so it should 
require very little maintenance and have a very long 
operating life. It can maintain both O^ and COj in an 
atmosphere as well as generate an atmosphere, al- 
though we chose to use it for little more than genera- 
tion. Also, it wiU combine with a computer-operated 
CA system very easily, although we chose not to do this 
due to other research objectives. 

The two problems we encountered were first, the 
high initial cost of the unit, and second, the absolute 
need for adequate air compressor capacity. Operating 
costs are limited to the power needed to operate the 
compressor and to maintain the temperature of the 
generator at 110°F. 

The hollow-fiber generator will not pull down a CA 
room as fast as can be done with liquid N2. However, 
the pull-down rate is sufficient to optimize CA condi- 
tions for apples, and the fact that the unit is always 
ready to operate as soon as the room is sealed may save 
time that would be spent obtaining liquid N, or prepar- 
ing for its use. In the short-run, use of liquid N^ is the 
less expensive method, but since the N2 generator 
should have a long, trouble-free life, in the long-run the 
costs may be comparable. 

In summary, while our experience with the hol- 
low-fiber, N2-generating system is not extensive, it has 
been very positive. These units should have a secure 
place in CA storage operations. While we have had no 
experience with a pressure-swing adsorption unit, a 
number of these are in use throughout the United 
States and in other countries, and experiences with 
them also have been positive. Thus, it appears that CA 
storage operators have a number of effective options for 
achieving CA atmospheres rapidly. The choice from 
among these options will depend on personal and local 
considerations. 



•i^ ftf# «fA «f# 9S3 

^« vj^ *^ *^ *4^ 



10 



Fruit Notes, Summer, 1989 



Seed Number in Apples Can Affect Calcium 
Accumulation and Keeping Quality 

William J. Bramlage, Sarah A. Weis, and Duane W. Greene 
Department of Plant & Soil Sciences, University of Massachusetts 



Apple growers are well aware of the importance of 
pollination and seed development for fruit set. How- 
ever, the importance of seeds continues throughout 
fruit development, affecting not just the fruit but also 
the tree. During experiments designed to test other 
questions, we have observed some of these relation- 
ships between seed number and fruit quality, which we 
shall describe briefly here. 

In a study of effects of growth regulators on Mcin- 
tosh apples, we found that vdth increasing concentra- 
tions of gibberellins A^^, and benzyladenine, an in- 
creasing number of seedless fruit remained on the 
trees and ripened. However, during and after storage 
the amount of senescent breakdown that occurred 
increased as growth regulator concentration that had 
been applied to the fruit increased. When the fruit 
were examined and analyzed, we found that the senes- 
cent breakdown was mostly in seedless fruit, and that 
the treatments were depressing fruit calcium concen- 
tration at the same rate that they were increasing the 
numbers of seedless fruit that matured. This result 
suggested that calcium was much lower in seedless 
fruit than in ones with seeds. 

In a later study of effects of growth regulators on 
Delicious apples, we again noticed large differences in 



seed numbers among fruit, so samples from all of the 
treatments were examined for size, seed number, and 
mineral composition. The results are summarized in 
Table 1. 

There was a significant linear relationship be- 
tween seed number and fruit diameter: the more seeds 
in the apple, the larger the apple. This relationship has 
been seen before with a number of different kinds of 
fruit, so one effect of abundant seed development ap- 
pears to be larger fruit size. 

It is well known that increasing fruit size reduces 
the amount of calcium in apples, yet as can be seen in 
Table 1 there was a significant increase in fruit calcium 
with increasing seed number. Thus, the extra calcium 
drawn into the apple as a result of increased seed 
number was greater than the dilution effect that the 
increased size had on fruit calcium concentration. The 
end result was larger fruit with more calcium in them. 
In the case of magnesium, the data on Table 1 show that 
it was reduced by seed number, but statistical analysis 
showed that this reduction was merely the dilution 
effect of larger fruit size. For potassium, seed number 
had no effect. Therefore, the effect of seed number was 
specific to calcium — increased seed number attracted 
extra calcium into the fruit. 



Table 1. Relationships of seed number per fruit in Delicious apples 
concentrations. 


to fruit size (diameter) and mineral 


Seed number 
per fruit 


Average 

diameter 

(mm) 




Mineral concentration' 




Calcium 




Magnesium 


Potassium 


0-1 
2-3 
4-5 
More than 5 

Significance^ 


67 
70 
71 
72 

*• 


174 
208 
215 
223 




284 
278 
279 
280 

** 


6700 
6600 
6600 
6600 

ns 


'Parts per million dry weight in outer cortical tissue. 
''•*,significantly different at odds of 99:1; ns, not significantly different. 



Fruit Notes, Summer, 1989 



11 



30 



Percent of Total 



without Breakdown 
With Breakdown 




to 1 



2 to 3 3 to 4 5 to 6 

Seeds per Fruit 



7 to 8 



Figure 1. Seed numbers for Mcintosh apples that did or did not develop senescent 
breakdown after 6 months of storage in 32''F air plus 1 week at room temperature. 
"Percent of total" is for each population — those that developed breakdown, and 
those that did not develop the disorder. 



In this experiment we did not determine the occur- 
rence of disorders after storage of fruit, because there 
were not enough fruit for a meaningful test. However, 
in another experiment we had the opportunity to relate 
seed number to keeping quality. 

Bushel samples of Mcintosh apples had been col- 
lected from 50 different blocks in commercial orchards, 
and all had been stored at 32°F in air at the Horticul- 
tural Research Center for 6 months. They were then 
kept at room temperature for 1 week, and each fruit 
was cut open, its seed number counted, and it was 
recorded as to whether or not senescent breakdown 
had developed. 

The results are shown in Figure 1. We examined 
the results as two populations of fruit — those that had 
breakdown and those that did not have it. In the 
population that developed breakdown, a high propor- 



tion of the fruit had 3 seeds or less. In the population 
that did not develop breakdown, most of the fruit had 
5 or more seeds. A statistical analysis showed that a 
real difference in seed number did exist between the 
two populations. Thus, in these Mcintosh from com- 
mercial orchards throughout Massachusetts, low seed 
number appeared to be a contributing factor (though 
certainly not the only factor) in development of senes- 
cent breakdown, a disorder caused by calcium defi- 
ciency. 

These results demonstrate that low seed number 
probably contributes to low calcium concentrations in 
Mcintosh and Delicious apples, and also contributes to 
calcium-related disorders during and following stor- 
age. This means that one approach to maintaining 
adequate calcium levels in apples is to pay careful 
attention to pollination conditions in orchards. Seeds 
are important contributors to fruit quality. 



*i0 •{# ^0 «f« miM 

w^ 0^ ^% «2^ «{% 



12 



Fruit Notes, Summer, 1989 



The following "Items from Here and There" are reprinted from 
Fruit Notes, June and Augfust, 1939. 



Items From Here and There 



William H. Ties 

Department of Pomology, Massachusetts State College 



Granville Grower Solves 
Deer Problem 

Karl Hanson, who owns an orchard in the town of 
Granville, has constructed a wire fence which seems to 
exclude deer in a section where much damage has been 
done in previous years. Mr. Hanson had to replace 
many of the trees in his orchard and found it impossible 
to get satisfactory tree growth before the deer were 
fenced out. The construction is briefly as follows. A 
barbed wire is stretched along the ground to prevent 
deer from getting underneath, and about 4 inches 
above that is stretched a section of woven wire, 39 
inches high. The top and bottom strands are number 
10 wire and the rest number 13. Above the top of the 
woven wire are 4 strands of heavy wire such as is used 
in growing covered tobacco, these strands being spaced 
as follows. The first, 8 inches above the top of the 
woven wire, the others 10, 12, and 14 inches, respec- 
tively. This makes a fence about 7 feet high. Mr. 
Hanson has found no evidence of deer jumping such a 
fence, although other growers have reported them 
jumping as high as 8 or 9 feet. There are still plenty of 
deer in that locality, although this orchard has been 
unmolested since the fence was built 4 years ago. 

Two Interesting Gadgets 

Yankee ingenuity is still fairly common in Massa- 
chusetts. Lee Rice of Wilbraham has devised a spray 
tank filler by mounting a small pump, similar to that 
used by the telephone company, on the front bumper of 
his truck which carries a supply tank. The pump is 
attached to the truck motor and makes possible the 
filling of the tank from a brook or pond in short order. 
Raymond Fiske of Lunenburg, instead of using a 
wooden frame or barrel for support in spraying from 
the top of the tank, has mounted an automobile tire at 
that point, thus providing a rubber bumper effect for 
weary bones. 



A Square Deal Without 
"Square Apples" 

A campaign is underway in the Wenatchee district 
to do away with "unnecessary and unwarranted mash- 
ing of apples in the packing shed." An attempt is being 
made to prevent a higher and higher bulge as the fruit 
leaves the packing house. The contention is made that 
there isn't the slightest reason for putting 45 lbs. of 
apples into a box and then stamping them with a 40 lb. 
stamp. Veiy often apples are not of uniform firmness 
and when they are squeezed together in the lidding 
process, the harder ones make virtually square apples 
out of the softer ones. 

Mcintosh Color Requirements 
are Too Low 

The color requirements for Mcintosh are too low, 
according to Cornell Memoir 220, "Joint Correlation 
Applied to the Quality and Price of Mcintosh Apples," 
published in March, 1939. After a detailed study of the 
various factors which surround a Mcintosh apple and 
of their relation to market price, the author, J. R. 
Raeburn, says, "The relationships of color to price 
indicated that apples with less than 67% of their skin a 
good red characteristic of the variety should not be 
permitted in the United States Elxtra Fancy grade, and 
those with less than 33% should not be permitted in the 
United States No. 1 grade." 

Red Sports are Often Picked 
Too Early 

W. E. Piper reports a well known Boston dealer as 
saying "A green Red Grav is worse than a green Green 
one." This seems to suggest a tendency among growers 
to pick red sports too early. If we harvest a Red Grav, 
Richared or other red sport as soon as it takes on a red 
color, we are sure to have a less edible apple than the 
color would indicate and about the only thing worth 
less than an immature, rubbery apple is two such 
apples. 



Fruit Notes, Summer, 1989 



13 



COOPERATIVE EXTENSION 

U. S. DEPARTMENT OF AGRICULTURE 

UNIVERSITY OF MASSACHUSETTS 

AMHERST, MASSACHUSETTS 01003 0099 



BULK RATE 


POSTAGE & FEES PAID 


USDA 


PERMIT No G?r)8 



OFFICIAL BUSINESS 
PENALTY FOR PRIVATE USE, $300 



SEPTAL 

UNIV. 



SECTION 
LIBRARY 



FN 



01003 






Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

University of Massachusetts Cooperative Extension, 

United States Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R. Autio and William J. Bramlage 



ISSN 0427-6906 



^ 







B'OLOGfCAL 

^^'^^ 1 7 1989 



Volume 54, Number 4 
FALL ISSUE, 1989 

Table of Contents 



The Use of Soil Applications of Gypsum to 
Increase Calcium Content of Apples 

Comparison of Slender Spindle and 
Vertical Axis Tree Training 

News from Other Areas 

Trends in the New England Apple Industry 

Advancements in Second-stage Apple IPM: Improving 
the Attractiveness of Baited Red Spheres 



Fruit Notes 

Publication Information: 

Fruit Notes (ISSN 0427-6906) is published the first day of January, 
April, July, and October by the Department of Plant & Soil Sciences, 
University of Massachusetts. 



The costs of subscriptions to Fruit Notes are $4.00 for United States 
addresses and $6.00 for foreign addresses. Each one-year subscrip- 
tion begins January 1 and ends December 31. Some back issues are 
available for $1.00 (United States addresses) and $1.50 (foreign 
addresses). Payments must be in United States currency and should 
be made to the University of Massachusetts. 



Correspondence should be sent to: 

Fruit Notes 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

University of Massachusetts 

Amherst, MA 01003 



COOPERATIVE EXTENSION POUCY: 

AJI chemical uses suggested in this publication are contingent upon continued registration. Thesechemicals should be 
used in accordance with federal and stale laws and regulations. Growers are urged to be familiar with ail current state 
regulations. Where trade names are used for identiHcation, no company endorsement or product discrimination is 
intended. The University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied, 
concerning the use of these products. USER ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY 
DAMAGE 



ksuedby the University ofMassachusetts Cooperative Extension, Stevenson W. Fletcher, Acting Director, in furtherance <^ 
the acts of May 8 and June 30, 1914. The University ofMassachusells Cooperative Extension offers equal opportunity in 
proffoms and employmenL 



The Use of Soil Applications of Gypsum to 
Increase Calcium Content of Apples 

William J. Bramlage, Sarah A. Weis, and John H. Baker 

Department of Plant & Soil Sciences, University of Massachusetts 



The problem of calcium (Ca) deficiency in apples is 
well known to our readers, as is the fact that we have 
researched various ways of alleviating this problem for 
many years. 

There are four ways of improving Ca content of 
apples: 

1. Orchard practices to reduce competition between 
leaves and fruit for available Ca. 

2. Soil applications of materials to increase uptake of 
Ca by apple tree roots. 

3. Foliar sprays of Ca-containing materials. 

4. Postharvest treatments with Ca-containing mat- 
erials. 

In general, soil treatments have been the least 
effective method of improving fruit Ca levels, because 
apple roots are very poor at absorbing Ca, which is one 
of the most abundant minerals in soil. This problem is 
increased by the very slow movement of Ca in an apple 
tree, resulting in slow and perhaps diluted responses to 
whatever improvement in Ca uptake that may have 
been achieved. 

Despite these problems, we have found that soil 
applications of gypsum (hydrated calcium sulfate) can 
increase apple frait Ca levels. An experiment begun by 
Mack Drake and John Baker in 1976 first showed these 
benefits, and another one begun by Bill Lord in 1980 
expanded on those findings. Since the retirements of 
Dr. Drake and Dr. Lord, we have assumed these experi- 
ments and established a series of new ones designed to 
answer questions raised by results from the original 
experiments. 

Research with soil treatments to influence apple 
nutrition progresses very slowly. First, trees respond 
slowly to soil treatments, and second, the soil is a very 
complicated system and when you change it, you must 
look at long-term effects of these changes. In 1987, we 
reported the promising results from the studies of Dr. 
Drake and Dr. Lord, and described some of the ques- 
tions that needed to be answered (Fruit Notes 52(2):1- 
4). Here, we have updated those earlier findings with 
what we have recorded during the past two years. 

In our 1987 article, we showed that 8 years of 
annual gypsum treatments to soil beneath mature. 



seedling- rooted Cortland trees had raised fruit and leaf 
Ca levels, decreased fruit and leaf Mg levels, and had no 
effect on fruit and leaf Klevels. The treatments had no 
effect on fruit firmness at harvest or after storage, but 
reduced the occurrences of bitter pit and senescent 
breakdown after storage. A second experiment applied 
to young Delicious trees also showed that gypsum 
increased Ca, decreased Mg, and had no effect on K, but 
no consistent effects on fruit quality were yet apparent 
at that time. We pointed out that we did not know what 
effects the treatments were having on soil propeities, 
that we did not know what the optimum application 
rate was, and that we did not know the economics of 
gypsum treatments. 

Currently, we have three long-term gypsum ex- 
periments in progress. The first is a continuation of the 
experiment begun by Dr. Lord in 1980, using a block of 
Sturdeespur Delicious trees on MM. 106 planted in 
1972. Trees in this block were given 0, 50, or 100 lbs. of 
gypsum (0, 0.3, and 0.6 lbs. per sq. ft.) each April 
through 1985, v^ath the gypsum spread beneath the 
tree canopy. By 1985, it was apparent that both 50-lb. 
and 100-lb. application rates were having the same 
effect, so the 100-lb. rate was discontinued to deter- 
mine how long effects would last after a gypsum treat- 
ment was ended. 

The second experiment was established in a block 
of mature Cortland trees on M.7 rootstock planted 
about 1962. These trees have a severe Ca deficiency, 
and their fruit always develop high rates of bitter pit 
and senescent breakdown. The objective was to see 
what role gypsum treatments might play in trying to 
control a chronic Ca-deficiency situation. Annual 
applications of 0, 40, or 80 lbs. of gypsum (0, 0.25, and 
0.5 lbs. per sq. ft.) beneath the tree canopy are made in 
April or May. The experiment was begun in 1986 and 
thus is in its fourth year. 

The third experiment was established in 1987 in a 
block of Cortland trees on M.7a rootstock planted in 
1981. Trees received applications of 0, 8, 16, 24, 32, 40, 
or 48 lbs. of gypsum (0, 0. 1, 0.2, 0.3, 0.4, 0.5, and 0.6 lbs. 
per sq. ft.) in April, in an attempt to learn the optimum 
rate of application. 



FmU Notes, Fall, 1989 



Percent of control 




125 

120 

116 

110 

106 

101 

S6 

BO 

86 

80 



Percent of control 



Fruit 



High rate 
diaoonllntMd 




-^<- 


Ca- 


60# oypMim/lr** 


-A- 


Ca- 


100# gypaum/tra* 


-*- 


Ma- 


ao# sypaum/traa 


-B- 


Mo- 


100# gypaum/traa 



88 



76'— 
80 



81 82 83 84 88 88 87 88 

Year 



Figure 1. Effects of low (50 Ibs./tree) and high (100 Ibs./tree) rates of gypsum, applied annually, on leaf 
and fruit mineral composition of Delicious. The high rate was discontinued after 1985. 



The soil type in these blocks is generally a Scituate 
fine sandy loam, although depth to hardpan and spe- 
cific soil characteristics varies somewhat among the 
blocks. 

Effects on Leaves and Fruit 

In the Delicious experiment, we continue to see the 
effects of gypsum on leaf and fruit mineral composition 
that we repoi-ted earlier, that is, gypsum significantly 
increases leaf and fruit Ca and decreases leaf and fruit 
Mg (Figure 1), but has no effect on leaf and fruit K (data 
not shown). The effects were quite consistent from 
year to year, with about a 20% increase in leaf Ca and 
a 10% increase in fruit Ca, and a 20% decrease in leaf 
Mg and a 5% decrease in fruit Mg each year after 
responses were established. This means that the re- 
sponse is very reliable, and also that you can get only so 
much response from a gypsum treatment: once the 
response is established, it does not get bigger as you 
continue to apply gypsum from year to year. It is also 
clear that it takes time for the tree to respond to 
gypsum treatments — in this case, it took 3 years after 
treatments began before the responses were estab- 
lished. 

In the trees where gypsum applications were dis- 
continued in 1985, it can be seen that levels of leaf and 



fruit Ca and Mg continued to show the gypsum effect 
for at least two years. In 1988, the third year, it 
appeared that levels might be starting to change, but 
we should have a much better picture of this after the 
1989 analyses are completed. It may be that 3 years 
represents the time needed for Ca to move from the 
roots to the fruit in these trees, since it took this long to 
see benefits of gypsum treatments, and perhaps this 
long to see any result of ending the treatment. 

The gypsum treatments had a very consistent ef- 
fect on the occurrence of bitter pit in these fruit (Figure 
2). Once the treatment effects were established, 5 to 
10% less of the crop has developed bitter pit after 
storage in the samples taken from gypsum-treated 
trees, except in 1986 when no bitter pit developed in 
any fruit. Again, as with the mineral analyses, it is 
clear that only so much could be done to alleviate Ca 
deficiency through gypsum treatments. They did not 
work magic! 

In the experiment with mature, Ca-deficient Cort- 
land trees, leaf Ca wtis increased and leaf Mg was 
decreased in the third year of treatment (Figure 3), as 
with the Delicious. However, there was no effect on 
fruit Ca or Mg, or on fruit quality, during the first three 
years. Since these trees were larger than the Delicious 
trees at the time their experiments were established, it 
may be taking longer for the Ca to travel from root to 



FmifAtoto, Fall, 1989 



26 



20 



IS 



% Bitter pit 



10- 



— •— No oypaum 

~A 100# gypsum/tr»« 



High 
rate 
discontinued 




Year 

Figure 2. Effects of annual applications of 
gypsum on the percent of fruit having bitter pit 
after 6 months of storage in air at 32°F. Effects 
were significant in 1985, 1987, and 1988. 





Percent of control 




110- 
105; 


- ^^'^^^'^^^^^^^^ 


<[>^^^'" *-^^ 


lOOlt- -^ _ ^~~'"^.^,__^_^ 




---. ^ 


»b- 








-^ Ca- 401 gypHin/tiM 


\ 




-^ C<- Mf gypiun/IrM 


\ 


90- 


-^ Mg- 40# oypMii/lr«e 


\ 




-B Mg- lOf gypwn/lrsa 


1 


B6 




— \ 



86 87 B8 

Year 

Figure 3. Effects of low (40 Ibs./tree) and high 
(80 Ibs./tree) rates of gypsum applications on 
leaf mineral composition of Cortland. There 
were no significant effects on fruit mineral 
composition. 



Table 1. Effects of different rates of gypsum application on leaf and fruit mineral 


analyses. 1988. Treatments 


were begun 


in 1987 beneath 6-year-old Cortland trees | 


on M.7a rootstock 


















Leaf 






Fruit 




Treatment 


























(Ibs./tree) 


Ca (%) 


Mg (%) 


K(%) 


Ca (ppm) 


Mg (ppm) 


K(%) 





1.23 


0.26 


1.34 


122 


388 


0.54 


8 


1.82 


0.25 


1.28 


138 


320 


0.51 


16 


1.40 


0.25 


1.40 


147 


334 


0.55 


24 


1.35 


0.22 


1.34 


142 


313 


0.50 


32 


1.46 


0.25 


1.30 


155 


337 


0.53 


40 


1.46 


0.24 


1.31 


144 


330 


0.52 


48 


1.43 


0.23 


1.34 


147 


325 


0.52 


Significance 


*•• 


« 


ns 


• 


ns 


ns 


Significance: ***, 


odds of 999:1; *, odds of 95:1; 


ns, not significant. 





Fruit Notes, Fall, 1989 



finiit in these larger trees. We should have a better 
picture of effects when 1989 samples are analyzed. 

A key experiment for us is the one in which differ- 
ent rates of gypsum are being applied, as it will help 
considerably in determining practical treatments. In 
only the second year of application to these young trees, 
results have begun to emerge (Table 1). Both leaf and 
fruit Ca levels were higher in the gypsum treatments 
than in the controls, vdth the hint that 16 lbs. per tree 
might be as effective as 48 lbs. per tree. Both leaf and 
fruit Mg were suppressed by gypsum, and neither leaf 
nor fruit K was affected by it. It will require several 
more years of data to establish response levels, but 
these results suggest that much lower rates of gypsum 
application than we have used in our previous experi- 
ments may be just as effective. These results also add 
to our view that tree size influences response time: 
fruit on these small trees responded in two years, while 
on the large Cortland trees, fruit did not respond in 
even the third year of treatment. 

Effects on Soil Properties 

It is important to know what effects the treatments 
are having on soil properties in order to judge long- 
term effects of gypsum applications. 

In 1988, we analyzed soil samples taken to hardpan 
in April in both the Delicious block and the mature 
Coitland block. Only the results for the Delicious block 
are presented here (Figure 4), since the results from 
the mature Cortland block were nearly identical. 

Gypsum greatly increased the exchangeable Ca in 
the soil throughout the entire soil profile. Thus, a huge 
reservoir of exchangeable Ca has been created on the 
treated soil. However, a shocking reduction of ex- 
changeable Mg and K also occurred. It is surprising 
that the suppression of leaf and fruit Mg has been so 
small (Figure 1), and even more surprising that neither 
leaf nor fruit K has been affected by gypsum treat- 
ments. Apparently, in this soil, before treatment there 
was much more exchangeable Mg and K than was 
needed to feed the apple roots, but less Ca than is 
desirable for optimum Ca uptake. 

There was no consistent effect of gypsum treat- 
ments on soil pH beneath the Delicious trees (Table 2). 
Similarly, there was no effect on pH beneath the ma- 
ture Cortland trees (data not shown). 

Discussion 

In 1987 we cautiously concluded that gypsum 
treatments could improve fruit Ca levels and fruit 
quality. Two more years of data remove some of the 
caution from our conclusions. 

It is evident that under our soil conditions, gypsum 



Depth (cm) 




2 4 a 8 10 

meq Calcium/100 g soil 



Depth (cm) 




0.2 a4 oj as 1 

meq Magnesium/ICO g soil 



Depth (cm) 




02 0.4 0.6 OJ 1 

meq Potassium/lOO g soil 

Figure 4. Effects of 8 years of annual applica- 
tions of gypsum (501bs./tree) on exchangeable 
Ca, Mg, and K at different depths of Scituate 
fine sandy loam soil. 



Frmt Notes, Fall, 1989 



Table 2. Effects of eight years of annual appli- | 


cations of gypsum 


(501bs./tree) 


on pH of soil at 1 


different depths beneath Delicious apple trees. 


Depth 






(cm) 


Control 


Gypsum 


0-10 


5.4 


5.8 


10-20 


5.4 


5.5 


20-30 


5.4 


5.4 


30-40 


5.5 


5.4 


40-60 


5.3 


5.3 


60-80 


5.2 


5.2 


Mean 


5.3 


5.4 


1 



treatments can improve fruit Ca levels and fruit qual- 
ity. It is also clear, however, that benefits are limited. 
Figures 1 and 2 convincingly demonstrate that only a 
relatively modest improvement can be achieved, but 
these Figures also show that a fruit grower can count 
on this level of benefit once treatment responses are 
established. Thus, it appears that gypsum treatments 
have a role in trying to control Ca deficiency in apples, 
but they are not a solution to Ca deficiency, a problem 
that is a part of modern apple production. 

We are still far from knowing what is the optimum 
treatment of gypsum. It appears that we have applied 
much higher rates than needed in our experiments to 
date, but several more years of data will be needed to 
clarify this. Likewise, we cannot tell yet whether or not 
annual treatments are needed. Even though treat- 
ments greatly increased exchangeable Ca in the soil, 
one cannot assume that trees can continue to benefit 
from this after annual treatment ceases. 

It is clear from these data that there is a long delay 
after gypsum is applied until the fruit begin to show 
increased Ca levels and improved quality. Results 
presented here suggest that at least two years are 
required, and that in large trees even three years may 
not be a long enough time. Responses of finiit to 
gypsum come slowly! 

It is also clear that a price is to be paid for improved 
Ca levels in fruit: the reduction in leaf Mg. In the 
results shown here, the reduction was small and did 
not increase over time, although in Dr. Drake's original 
gypsum experiment, the reduction in leaf Mg became 
greater each year of treatment. The severe reduction in 
soil exchangeable K is also troubling. Perhaps in other 
orchards, leaf K might be reduced. There is also the 
possibility that some other element, such as manga- 
nese might be influenced by such large effects on soil 



chemistry. Thus, it is imperative that an orchardist 
who tries gypsum treatments employ a careful leaf 
analysis program to monitor the mineral nutrition of 
the trees. 

It should be noted that gypsum is well known to 
improve the physical properties of soil, and in particu- 
lar to improve water penetration. Thus, gypsum may 
help maintain good soil properties, especially in herbi- 
cide strips where soils can lose their structure over 
time. 

It should be pointed out also that gypsum is not a 
substitute for lime, and vice versa. As seen in Table 2, 
gypsum did not change pH, so it did not change the 
liming needs of the soil. Gypsum is much more water 
soluble than lime, and quickly penetrates through the 
soil profile (Figure 4). Lime, in contrast, quickly affects 
only the soil area where it was applied, moving only 
very slowly down through the soil. If an orchardist is 
using gypsum, then liming should be done with only 
dolomitic limestone, to help offset the loss of soil Mg 
due to gypsum (Figure 4). 

We cannot judge the economics of gypsum treat- 
ments from our experiments. At this point, we do not 
know what is the optimum rate of application, or 
whether or not annual treatment is required. Also, we 
do not know what is the most economical materied to 
apply. 

In our experiments, we have used mined, ground 
white gypsum, which is relatively expensive. There are 
other grades of mined gypsum, which, because they are 
not white, cannot be used in wallboard and thus are 
less expensive. Also, there are vast quantities of mate- 
rials available at many power plants that are the result 
of purging smokestacks of sulfur emissions. A series of 
studies have suggested that these materials may be as 
effective as mined gypsum when applied to the soils. 
We have not used any of these materials, but they may 
be available at little or no cost other than transporta- 
tion. Indeed, use in orchards may be a desirable way of 
disposing of such waste materials. 

Clearly, many questions about use of gypsum or 
gypsum-like materials to improve fruit Ca levels re- 
main to be answered. However, our results strongly 
suggest that treatments can produce consistent, albeit 
modest, improvements in fruit Ca and quality. Such 
treatments will not solve the Ca-problem in apples, but 
may be a part of the program needed to cope with Ca 
deficiency, which is such a general part of modern apple 
production. 

Acknowledgement 

We wish to thank Agway, Inc., Syracuse, New 
York, for their financial support during the course of 
these experiment. 



•S» *3* »i* *i* •!• 

*{• 0g» *{* 0^ *g» 



Fruit Notes, Fall, 1989 



Comparison of Slender Spindle and Vertical 
Axis Tree Training 



Kathleen Williams 

Washington State University 

As the Pacific Northwest tree fruit industry moves 
into the 2P' century, there will increasingly be an 
emphasis on improving orchard labor efficiency and 
fruit quality, as well as promoting early production. 
Labor for pruning and harvesting operations is, and 
will continue to be, the most expensive aspect of pro- 
ducing fruit. Improved labor efficiency depends on 
improved orchard design. 

Large trees of the Pacific Northwest (PNW) cen- 
tral leader system pose significant problems in terms of 
orchard labor efficiency and fruit quality. We as an 
industry are looking to other orchard systems, primar- 
ily from western Europe, to improve our orchard effi- 
ciency. 

Two promising systems, the slender spindle from 
the Netherlands and the vertical axis from France, are 
currently under test in Washington State. Both of 
these systems use a central leader tree with a support- 
ing framework of laterals. 

However, there are significant differences in prun- 
ing and training techniques for producing trees in 
either of these orchard systems in comparison with, the 
PNW central leader system. 

Slender Spindle 

The slender spindle orchard system was developed 
in the Netherlands in the mid 1960's and has been 
refined throughout the past 20 years. The system was 
developed to optimize light interception and distribu- 
tion throughout the tree canopy under the low-hght 
conditions in the Netherlands. Furthermore, the trees 
had to be physically easy to train, prune, and maintain, 
because the Dutch labor supply depends on the local 
people. The trees also had to begin producing early to 
repay the high initial capital expenditure required and 
allow growers the option of replanting their orchards to 
newer, more profitable cultivars. 

The slender spindle and vertical axis systems were 
developed and continue to be utilized primarily in the 
management of non-spur cultivars such as Golden 
Delicious. 

The slender spindle tree is a pyramid-shaped tree 
that is always planted on a dwarfing rootstock, mainly 



M.9. Trees are supported with either a post or stake. 
Tree height is maintained at 6 to 7 feet, and tree spread 
is generally restricted to 3 to 3.5 feet in a single row 
design. Tree density is 1,000 trees or more per acre, 
depending on the tree spacing. (See Table 1.) 

Training the Slender Spindle Tree 

Year 1—At Planting 

A branched or "feathered" nursery tree is always 
preferable to a non-branched "whip" as planting stock, 
because production wall occur at least one year earlier. 
The branched tree is headed 10 to 15 inches above the 
highest retained branch. If there are upright branches 
present which cannot be trained to a more horizontal 
angle, they are removed. Branches below 18 inches 
above the soil line are removed, because they will 
interfere with herbicide applications, and the fruit will 
be too low for convenient and clean harvest. If a whip 
is planted, it is headed 33 to 30 inches above the soil 
line. 

Year 1 - Summer (First Leaf) 

Vigorous branches are tied or weighted down to 
the horizontal with non-spur cultivars. For spur types, 
a less extreme horizontal angle is appropriate, e.g., 45 
to 60 degrees. It is important with spur types not to 
train weak branches to a horizontal angle; the branches 
will be devigorated by fruiting and will eventually 
"runt out". 

The optimum time for limb positioning, if tying or 
weighing down, is mid July to mid August. However, 
earlier improvement of branch angles v«th young 
shoots three to six inches in length can be achieved 
with clothespins or toothpicks. 

Care must be taken to keep the terminal ends of the 
branches at a horizontal or slightly vertical angle; they 
should not be allowed to bend down, as this can cause 
excessive vigor in the lower portions of the branch. On 
spur types, extreme downward bending can be too 
devigorating. 

The first summer is when most of the pruning is 
conducted on the young slender spindle tree. Vigorous 



FruU Notes, Fall, 1989 



Table 1. Comparison of central leader training systems for non-spur apple cultivars (after Barritt, 1984). 






Hi 


> 




,4^ 


1^ 


y 






V&. 


J^ 


! 


r^ 




? 




PNW Head & Spread 


J_ 

Vertical Axis 


Slender Spindle 


Tree height 


10-15 feet 


10-14 feet 


7-8 feet 


Tree spread 


7-10 feet 


4-6 feet 


4-6 feet 


Spacing of single 
rows 


16-20 feet 


13-16 feet 


10-12 feet 


Tree density 


200-400 trees/acre 


450-800 trees/acre 


700-1100 trees/acre 


Rootstocks 


M.26, M.7, MM.106 
MM. Ill, seedhng 


M.9, M.26, M.7 


M.9, Mark 


Tree support 


None 


Pole & wires 


Post or stake 


At planting 
head the tree 


Yes 


Yes 


Yes 


Select 3-5 permanent 
lower scaffolds 


Yes 


Yes 


Yes 


Head leader in 
dormant season 


Yes 


No 


No 


Pruning of central 
leader after 
year 1 


Head into 1-yr-old 

wood. To maintain 

height, cut to lateral. 


No heading. To maintain 

height, cut to 

replacement leader. 


Head to competing 

lateral on older 

wood. 


Remove central 
leader to weaker 
side shoot in 
each dormant season 


Yes 


No 


No 


Head scaffolds in 
dormant season 


Yes 


No 


No 


Spread or tie down 
branches 


Yes, 45° 


Yes 


Yes, to horizontal 


Control limb length 
by cutting back 
into older wood 


Yes 


Yes 


Yes, lower tier 


Control limb length 
by removal to trunk 


No 


Yes, upper limbs, 
leaving a stub. 


Yes, upper limbs, 
leaving a stub. 


1 



FmU Notes, Fall, 1989 



upright branches which compete with the leader are 
removed. The desirable branches to leave are weak and 
horizontal. 

Year 2 — Dormant Pruning 
(First Dormant Season) 

If summer training and pruning operations were 
conducted during the first growing season, very little 
dormant pruning is required. However, if vigorous 
branches or upright grov^h were not removed, now is 
the time to do this operation. 

Vigorous growth should not be allowed to remain 
for two seasons; the growth and vigor of the leader and 
other lateral branches vdll be unbalanced. 

The central leader is removed by heading into two- 
year-old wood to a competing lateral. An alternative 
method of central leader vigor control is to bend over 
the central leader the previous summer, then return 
the leader to the other side of the supporting post the 
following spring (May or June). 

In this method, no heading cuts are made during 
the second winter. The leader of a non-spur cultivar 
should not be headed into one-year-old wood. 

The scaffold branches for the lower permanent tier 
are selected; there are generally three to five perma- 
nent lower branches. Scaffold branches are NEVER 
headed into one-year-old wood, as this type of pruning 
cut is too invigorating. Also, heading cuts into one- 
year-old wood delay fruiting. 

Year 2 — Summer Training and Pruning 

As in year 1, limb positioning of lateral branches 
should be continued and undesirable growth removed. 
Proper limb positioning is critical for flower bud initia- 
tion and development. Growth which competes with 
the leader or is excessively vigorous should not be 
allowed to develop during the growing season. 

Timing and techniques for training and pruning 
are the same as those for year 1 summer. 

Years 

The tree should be in commercial production by 
year 3 (third leaf), if a branched nursery tree was 
planted. Dormant and summer pruning utilize the 
same techniques as employed in the first growing 
seasons. 

However, lower scaffolds will need to be shortened 
with the use of stubbing cuts into two-year-old wood. 
The leader v^all continue to be pruned to a replacement 
lateral or tied over as in previous years. 

Continued pruning of the central leader to a com- 
petinglateral, which is then trained upwards results in 



a central leader with a zigzag shape. This zigzag 
configuration helps to reduce excessive growth in the 
top of the tree as the tree matures. 

Year 4 

By the fourth leaf, maintenance pruning is con- 
ducted. There are three major steps to remember: 

1. Renew upper scaffolds: after a branch has fruited, 
it is generally removed completely, leaving a short 
stub. 

2. Shorten lower scaffolds: head to aweak lateral on 
older wood. This is used to restrict the tree to its 
allotted space. 

3. Control central leader growth: use either replace- 
ment pruning or tying down. After year 5, the 
central leader is generally controlled by cutting to 
a competing lateral on two-, three-, or four-year- 
old wood. Bending over the leader is not recom- 
mended. 

The same principles as outlined above are em- 
ployed throughout the life of the mature slender 
spindle orchard. Special caution is advised concerning 
the vigor of the tree, particularly at the top of the 
canopy. The growth MUST remain weak and must be 
continually renewed after fruiting. 

If the top is allowed to become vigorous and domi- 
nant, the fruiting portion of the lower third of the tree 
is eliminated. All parts of the tree must receive light. 
Shading also reduces fruit quality. 

The slender spindle system as described above is 
the "pure" system. Modifications wall be devised to fit 
Pacific Northwest growing conditions. The higher 
light incidence and longer growing season in a desert 
climate, as compared to the Netherlands where the 
system was developed, will certainly mean that we 
must adapt the slender spindle tree for our needs and 
purposes. A taller slender spindle tree (eight feet) 
would utilize light efficiency under Pacific Northwest 
growing conditions. 

It may be necessary to use more heading into one- 
year-old wood than the original slender spindle system 
allows. Treatment of the leader may be modified to 
light tipping on varieties such as Granny Smith, which 
may require more feathery growth at the top of the 
canopy, and tying, rather than heading, for devigora- 
tion. 

Vertical Axis 

The "axe centrale" or vertical axis tree training 
system was developed by Lespinasse in the 1970's. It is 
a central leader tree trained to a three- or four-wire 



FmU Notes, Fall, 1989 



trellis. Modifications of the trellis have heen success- 
fully employed, such as a one-wire trellis with bamboo 
stakes for individual tree support. 

Generally, trees are 10 to 14 feet high, depending 
on the rootstock used, and about five to six feet wide. 
Rootstocks range from M.9 to MM. Ill under French 
conditions, with MM. Ill recommended for severe re- 
plant sites. Tree density ranges from 500 to 600 trees 
per acre. 

Trees are usually planted in single rows, as op- 
posed to the multi-row bed system used frequently 
with the slender spindle. The tree has a narrow 
pyramid shape, with an open (sparse) top. (See Table 
1.) 

Training The Vertical Axis Tree 

Year 1 - At Planting 

If unbranched trees ("whips") are planted, it is 
advisable to head the tree 30 to 33 inches above the 




Figure 1. Do not allow vigorous growth to remain on the vertical 
axis tree. The most desirable wood to retain is weak and horizon- 
tal. 



ground to force lateral branching. Preferably, 
branched or feathered trees are utilized. As originally 
described, heading of the central leader is not done. It 
may be advisable to head the leader 10 to 12 inches 
above the highest retained branch. This type of head- 
ing cut encourages the development of a strong, perma- 
nent lower tier of branches. As with the slender 
spindle, branches that have poor angles, or that are 
lower than 18 inches above the soil line, are removed. 

Year 1 — Summer 

Limb positioning is an important aspect of tree 
training for the vertical axis. Weights and strings are 
most commonly used. In a non-spur cultivar, branches 
can be trained to the horizontal. For a spur type, a more 
moderate branch angle, i.e. 45 to 60 degrees, is advised. 
Early summer pruning is an essential part of tree 
training. Branches that are overly vigorous with nar- 
row angles are completely removed (thinning cuts) in 
May and June, when three to six inches long. In fact, 
if rigorous summer pruning is con- 
ducted, little or no dormant prun- 
ing is required the subsequent 
winter. (See Figure 1.) 

The leader must be supported 
by tying it to the supporting pole. 
Plastic tubing and tape are com- 
monly used. Nylon string is not 
advised, because of risks of girdling 
the leader. 



Year 2 — Dormant Pruning 

No dormant pruning is re- 
quired if summer pruning has been 
utilized. If no summer pruning 
was done, remove competing later- 
als, vigorous upright growth, low 
branches, and poorly placed 
giowth. Do not head the leader. 

Year 2 — Summer Training 
and Pruning 

Tree training and pruning 
techniques are identical to those 
used for year 1. Caution: do not 
allow vigorous growth to remain on 
the tree. (See Figure 1.) The most 
desirable wood to be retained is 
weak horizontal growth. 

Year 3 — Dormant Pruning 

Remove uprights and vigorous 
branches. Do not head the leader. 
Vei7 little pruning is required. 



Fmit Notes, Fall, 1989 



Year 3 - Summer Training and Pruning 

As in the previous two summers, special attention 
must be paid to eliminate overly vigorous fruiting 
branches. In addition, the vigor of the top of the tree 
must be controlled. One of the easiest methods of 
controlling top vigor is to let the leader bend over above 
the point of central leader support with the weight of 
cropping. Later, the portion of the central leader above 
the support that has become pendulant is removed 
entirely. This process will likely be repeated in subse- 
quent years. It is important to remove strong upright 
growth at the top of the tree; this growth can interfere 
with fruit bud formation in the bottom poilion of the 
tree. 

Year 4 — Dormant Pruning 

The lower scaffolds are permanent branches and 
must eventually be shortened. Shortening to lateral 
branches is used to contain the lower scaffold branches 
to their allotted space. Also, the weight of the crop 
bends the branches downward, and so branches are 
pruned to promote a more horizontal growth habit. 
(See Figure 2.) 

Vigorous growth is removed and replacement 
branches selected in the upper poition of the tree. If a 
branch has been fruited and requires replacement, an 
angled stub is made. (See Figure 2.) A new branch will 
emerge from adventitious buds and can then replace 
the old branch. 

Pruning the mature vertical axis tree employs the 
same techniques as that of the slender spindle: 



1. 



2. 



3. 



The lower permanent scaffold branches are short- 
ened to weak lateral branches (preferably, fruiting 
laterals) to contain their length. 
The upper two-thirds of the canopy receive re- 
newal pruning. Fruitinglaterals are not allowed to 
remain in the tree for more than three or four 
years. Constant renewal of the fruiting wood is 
critical to keep the mature vertical axis tree pro- 
ductive. 

Light must reach every portion of the tree. If light 
islimiting, production will be affected. Special care 
must be taken to keep the top of the tree weak to 
prevent shading in the bottom section of the tree. 



Summary 



Both the slender spindle and the veilical axis train- 
ing systems are central leader systems. There is a 
dependence on summer pruning for tree training (limb 
positioning) and a lack of heading into one-year-old 
wood. Renewal pruning and limb shortening are criti- 




Figure 2. Vigorous growth is removed and re- 
placement branches are selected in the upper 
portion of the vertical axis tree. 



cal to the success of these systems. 

The systems differ in how the central leader is 
handled. With the slender spindle tree, the centred 
leader is headed into two-year-old wood (or older) to a 
replacement lateral which is tied upward to continue 
the central leader. In contrast, the vertical axis leader 
is never headed, except at planting. 

Both the slender spindle and vertical axis systems 
will produce more quickly - if handled correctly - than 
the traditional PNW central leader system. In addition 
to earlier production, there is the advantage of im- 
proved labor efficiency. 

Changing to high density systems in the Pacific 
Northwest will not be a matter of "if," but "when." 

This article was reprinted from Good Fruit 
Grower, June, 1989. 



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10 



FruU Notes, Fall, 1989 



News from Other Areas 



Editors' Note: The following two items are reprinted from "Garden," the Journal of the 
Royal Horticultural Society, London, England in their August, 1989, issue. 



Hope for National Fruit Collection 

There is now more than a ghmmer of hope about 
the future of the National Fruit Collection at the 
Brogdale Research Station in Kent, which is under 
threat from Government cutbacks. Having held the 
collection in the past, the Royal Hoiticultural Society is 
deeply concerned that the threatened closure of 
Brogdale may mean the loss of the world's largest col- 
lection of apple cultivars - an incomparable treasure 
trove of genetic material for breeders and nurserymen 
the world over. 

Government ministers have now given a commit- 
ment to secure the future of the collection for a few 
years. What this entails is still uncei-tain and it is likely 
that the Collection will need to be moved over the next 
five years. 

The Royal Hoiticulture Society was approached by 
the Ministry of Agriculture, Fisheries and Food to 
consider housing the Collection (apple cultivars in 
particular) at the Wisley RHS Garden in Surrey, and 
indicated that "it would be prepared to do this if the 
source of funding for the maintenance was secured." 
The Society already has 700 apple cultivars in cultiva- 
tion at Wisley - a third of the Brogdale Collection. 

Wye College, in Kent, offers another possible site 
and the College is keen to take responsibility for the 
National Fruit Collection - again provided adequate 
funding is available. Wye is remarkably well placed for 
the purpose. It is in the right location, has appropriate 
soils and has the space and expertise to maintain the 
Collection. The RHS would be happy to support the 
College in its application. 

There remains the problem of raising the one 
million pound (about $1.5 million) endowment fund 
estimated to be required to safeguard the future main- 
tenance of the Collection. It is vital to the future of the 
fruit-growing industry that this unique collection of 
world-wide importance is saved. 



Survey of Old Apple Cultivars 

The National Council for the Conservation of 
Plants and Gardens (NCCPG) is making a survey of old 
cultivars held in small collections and as individual 
trees in private gardens. 

When completed it will be possible to assess which 
cultivars are in the gieatest danger of becoming lost 
and where the greatest effort must be made to save 
them. 

Initially all culinaiy and dessert cultivars (not ci- 
der) produced before 1900 are being listed. This list 
will be extended if necessaiy. 

The NCCPG is asking for information from anyone 
who grows old cultivars. The information they need is: 

1. The names and numbers of each cultivar held in 
collections or as individual trees. 

2. Their approximate age. 

3. The location. 

If 'local' names only are known, please give these 
with a brief description of the fruit and its season of 
ripening. 

As the Council anticipates a large number of re- 
plies it regrets that letters cannot be answered. How- 
ever, if the survey reveals that certain cultivars are in 
a parlous state, the owners will be contacted with a 
view to providing propagating material. 

Please send details to: Mr. S. F. Baldock, Fruit 
Collator for the NCCPG, Costrels, Eaton Bishop, Here- 
ford. HR2 9QW. England. 




Fruit Notes, Fall, 1989 



11 



Trends in the New England Apple Industry 



Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 



New England fruit growers produce 7.8 million 
bushels of apples on 24,000 acres of land. Figure 1 
shows the acreage planted to apples in each of the New 
England states. The size of individual orchards is 
generally larger in northern New England (ME, NH, 
VT) than in southern New England (MA, RI, CT) 
(Figure 2). In northern New England 75% of the crop 
is grown for a wholesale market; whereas, only 47% of 
the southern New England crop is sold wholesale 
(Figure 3). 

In 1989 a survey was conducted to study the New 



Acres (Thousands) 




Figure 1. Total acreage of apple production in each 
New England state. 



Average acreage per farm 



NH 



ME 



VT 




MA 



Figure 2. Average acreage per farm in apple pro- 
duction. 



Percent wholesale 



62% for New England 




Figure 3. Percent of the annual production sold in 
a wholesale market. 



England planting trends. (RI data are not included due 
to insufficient returns.) Figure 4 shows the percentage 
of each state's 1989 acreage planted before 1980, be- 
tween 1980 and 1984, and between 1985 and 1989. The 
least planting has been done in Maine, vnih only 18% of 



100 



80 



60 



40 



20 



Percent of total 



Year ot planting: 
^H Before 1980 
^S 1980-84 
1966-89 




Figure 4. Percent of each state's total apple acre- 
age planted before 1980, between 1980 and 1984, 
and between 1985 and 1989. 



12 



FmU Notes, Fall, 1989 



Mcintosh 

Cortland 

Delicious 

Macoun 

Paulared 

Empire 

Golden D. 

Baldwin 

Jersey Mac 

N.Spy 







\ ■> ^ V 










■«+' 

^ 




MA 


L 








i 






m 1970 




i 






IZ2 1976 




r 






■ 198d 




) 






^N 1994 








I > 





15 30 45 60 

Percent of total 



75 



Mcintosh 
Cortland 


Vl'IVi'Vi'l'i 


4m 


W#^ 


li 

NH 


Delicious 
Paulared 




? 


Macoun 


\ 










Empire 


h 










Mutsu 


! 










Rome 


) 










Qolden D. 


^ 










Baldwin 


2? 




1 


1 





15 30 45 

Percent of total 



60 



75 



Mcintosh 

Delicious 

Macoun 

Cortland 

Empire 

Golden D. 

Idared 

Rome 

Paulared 

Mutsu 




^r^^ffg 



^ 



CT 



15 30 45 60 

Percent of total 



75 



Mcintosh 


'i'['ivri'('iviV('tYtri^u 


Delicious 
Cortland 




1 






ME 


Golden D. 


^ 


Paulared 


!, 










N.8py 


/ 










Macoun 


1 










Vista Bella 


1 










Jersey Mac 


S 










Empire 


) 


1 









15 30 45 60 

Percent of total 



75 



Mcintosh 
Cortland 




m^ 


*w* 


WW 


VT 


Delicious 
Empire 
N.Spy 






Paulared 


\ 










Spartan 


\ 










Macoun 


1 










Qolden D. 


? 










Rome 


? 





1 1 


. 



15 30 45 

Percent of total 



60 



75 



Figure 5. The percent of the total acreage 
planted to the top 10 cultivars. Data from 
1970, 1976, and 1989 are included, as well 
asprojections for 1994. The 1970 and 1976 
data are from the New England Crop Re- 
porting Service's 1970 and 1976 New 
England Fruit Tree Surveys. 



FniU Notes, Fall, 1989 



13 



Percent of total 




Percent of total 



^1980-84 
■ 1990-94 



Mdnto Cortia Empire Macoun Paular Libert Delici 



70 
60 
50 
40 
30 
20 
10 




Percent of total 



NH 


■ • / 

/ 

/ 


- / 


- / 

- / 


-/ 


1 IJ 




J Fl^ B:^ 



Mclnto Libert RedFre Gala Cortia Empire Delici 



Percent of total 





r Jn P l JLFL - 



Mclnto Cortia Jonago Empire Macoun Golden Delici 



Percent of total 




4^ 13-^ 



Mclnto Empire Cortia Libert Macoun Delici Paular 



Figure 6. The percent of the total planted 
acreage devoted to 7 different cultivars in 
1980-84, 1985-89, and proposed for 1990- 
94. 



Mclnto Cortia Macoun Rome Mutsu Empire Delici 



14 



Fruit Notes, Fall, 1989 



100 



80 



Percent of total 



60 - 



40 



20 



MA 



DJ 1970 

■I 1989 
.E3. 1994 . 



.Ml 



Jl 



rJ-ru-l □ n 



100 



SO 



60 



40 



20 



Sding MM lit MM 106 M.7 M2B M9 Mark lntr«tm 



Percent of total 



NH 




J 



_□_ 



100 



so 



SdIng MM.111MU.106 M.7 M.26 M.g Mirk Intrttm 



Percent of total 



60 - 



40 



20 - 



CT 


2 ' 








- , 


1 


J 


rfr 




^ 



Sdlng MM.111MM.106 M.7 M.2e M.9 Mark Inlralm 



100 



80 



60 



40 



20 



Percent of total 



ME 



JE^ 



J 



^ 



_fi_Jfi 



100 



80 



60 



40 



Sdlng MM.111MM.106 M.7 M.26 M.9 Mark Inlralm 



Percent of total 



20 






■-^ 



VT 




^^n 



-o S. 



SdlfM] MM.111MM.106 M.7 M.26 M.9 Mark Inlralm 



Figure 7. The percent of the total acreage 
planted to various rootstocks. Data from 
1970, 1976, and 1989 are included, as well 
asprojections for 1994. The 1970 and 1976 
data are from the New England Crop Re- 
porting Service's 1970 and 1976 New Eng- 
land Tree Fruit Surveys. 



FmU Notes, Fall, 1989 



15 



'ercent of total 




Percent of total 



70 
60 
50 
40 
30 
20 
10 


70 



Sding MM.tt1 MM.106 M.7 M.26 U9 Mark Intritm 



Percent of total 



NH 



, Dbx. 






y 
-/ 
-/ 
:/ 
-/ 

/ 

/ 
/ 



WjI-- 




Sding MM.111 MM.106 M.7 M.26 M.9 Mark Intralm 



Percent of total 



60- 

50 

40 

30 

20 

10 



CT 




xfi 



n. 



i 




SdIng MM.111 MM.106 M.7 M.26 M9 Mark Intntm 



Percent of total 




SdIng MM.111 MM.106 M.7 M.26 M.9 Mark Inlratm 



Figure 8. The different rootstocks that 
have been planted during the periods 1 980 
through 1984 and 1985 through 1989, and 
are projected by growers for the period 
1990 through 1994. 



Sdino MM.111 MM.106 M.7 M 26 M.9 Mark Intratm 



16 



Fruit Notes, Fall, 1989 



the acreage less than 10 years old. Vermont, on the 
other hand, has 39% of its acreage less than 10 years 
old. Based on the intent of growers, as expressed in the 
survey, it is estimated that 16% of the acreage will be 
replanted in the next 5 years. 

The primary intent of the survey was to determine 
cultivar trends. Figure 5 presents the top 10 cultivars 
in 1989 for each state. Also included are data for 1970 
and 1976. A projection for 1994 is given, assuming that 
70% of the trees removed will be Mcintosh, 15% will be 
Delicious, 5% will be Cortland, and the remaining 10% 
will be small amounts of various other cultivars. 

Mcintosh alone accounts for about 58% of the 
acreage in New England and will continue to be the 
primary cultivar; however, it is likely that the acreage 
of Mcintosh will dechne in the next 5 years. Other 
important trends in these data are the dramatic decline 
of Delicious that has occurred and will continue to 
occur, and the increases of Cortland, Macoun, Empire, 
and Paulared. 

Since a relatively small portion of the total acreage 
is planted each year, the data presented in Figure 5 do 
not give an accurate estimate of trends. Figure 6 gives 
the planting which occurred during the last two 5-year 
periods and is projected to occur during the next 5-year 
period. It is clear that in all but Connecticut the per- 
centage of trees planted which are Mcintosh will de- 
cline over the next 5 years. Delicious has declined 
dramatically as a percent of the total planting and will 
continue to decline. Liberty, Jonagold, Redfree, and 
Gala planting will increase substantially in the next 5 
years. The disease-resistant cultivars alone will ac- 
count for 10% of the planting during this time. 

The percentages of the acreage planted to trees on 



various rootstocks are presented in Figure 7. In 1970 
approximately 90% of all of the trees in New England 
were on seedling rootstocks. Now only 42% are on 
seedling roots, with M.7, MM. 106, and MM.lll ac- 
counting for 47% of the acreage. The 1994 levels were 
projected eissuming that 90, 2, 3, 4, and 1% of the trees 
removed in the next 5 years will be on seedling, 
MM.lll, MM.106, M.7, and interstems, respectively. 
The amount of the acreage devoted to trees on seedling 
rootstocks will continue to decline, and the full dwarf- 
ing rootstocks (M.26, M.9, Mark, etc.) will account for 
significant portions of the acreage by 1994. 

As with cultivars, overall levels do not give an 
accurate picture of trends, since only small portions of 
the acreage are replanted each year. Figure 8 shows 
the planting which has occurred over the last two 5- 
year periods and will occur over the next 5-year period. 
Since 1980, most trees have been on M.7, MM. 106, and 
MM.lll, accounting for 82% of the total. However, a 
dramatic change will occur during the next 5 years, 
with dwarfing rootstocks accounting for 62% of the 
planting. Mark and M.26 will account for 28 and 22% 
of the total, respectively. 

The New England apple industry is experiencing a 
great deal of change. The decline in Mcintosh and 
increase in other cultivars is certainly related to the 
loss of Alar^". An increase in the planting of disease- 
resistant cultivars is likely related to the broader con- 
cern about pesticides. The increased use of dwarfing 
rootstocks is somewhat due to the loss of Alar, but also 
may be related to an increasing interest in a smaller 
tree vdth the potential for higher profitability. It is 
clear that the New England apple industry is bracing 
for the future vnth these important and necessary 
changes. 



•!• »Sm •!» tS* •S* 
*{* 0f» r^ »f» rg» 



Fruit Notes Founder Dies 



Wilbur H. Thies, Professor Emeritus, University 
of Massachusetts, died July 29, 1989. He was born in 
Leland, Michigan, October 24, 1892. He graduated 
with a B.S. degree in 1919 and a M.S. degree in 1925 
from Michigan Agricultural College (now Michigan 
State University). In 1924 he joined the Horticulture 
Department at Massachusetts Agricultural College 



(now University of Massachusetts) as Extension Hor- 
ticulturalist. In July, 1935 he founded Fruit Notes and 
continued to write for and edit it until his retirement 
from the University on February 1, 1955. Memorial 
services were held September 30, 1989 at the North 
Congregational Church of Amherst, Memorial gifts 
may be made to one's favorite charity. 



Fruit Notes, Fall, 1989 



17 



Advancements in Second-stage Apple IPM: 
Improving the Attractiveness of Baited Red 
Spheres 

Ronald J. Prokopy, Jian Jun Duan, Patricia Powers, 
and Max P. Prokopy 

Department of Entomology, University of Massachusetts 



We previously reported [Fruit Notes 54(1): 1-5] on 
results of the second year of our pilot second-stage 
apple IPM program in Massachusetts commercial or- 
chards. One of the major elements in second-stage IPM 
is the use of red spheres baited with synthetic apple 
odor for intercepting immigrating apple maggot flies at 
the orchard perimeter. We concluded that before such 
an interception system for maggot fly control could be- 
come broadly successful on a commercial level, some 
improvements would be needed. One improvement 
might be enhancing the attractiveness of spheres to 
apple maggot females, to ensure better capture of a 
high proportion of females flying from border areas 
onto apple trees at the orchard perimeter. Here, we 
describe results of 2 studies conducted in 1989 toward 
this goal. 

The first study involved evaluating different sizes 
of unbaited red spheres. More than a decade ago [Fruit 
Notes 41(6):6-9], we found that spherical shape (mim- 
icking apple shape) was more attractive to maggot flies 
than cubical, cylindrical, or rectangular shape. We also 
discovered that red and 
black spheres were equally 
attractive as colors and 
more attractive than 
green, orange, yellow, or 
white spheres. We chose to 
use red spheres over black 
ones to permit better vi- 
sion of a captured maggot 
fly. Finally, we found that 
8-cm-diameterred spheres 
were more attractive than 
spheres of 4,6,15,23,30, or 
45 cm in diameter. Here, 
we wondered if there were 
any sphere size between 8 
and 15 cm that might be 
more attractive than the 8 



We purchased softballs (10 cm), toy balls (14 and 
18 cm), and volleyballs (23 cm), painted them the same 
red color as our standard 8 cm croquet balls, coated 
them v^ath sticky, and hung them in non-sprayed fruit- 
ing apple trees harboring a low population of apple 
maggot flies. Foliage and fruit within 10 cm of the 
sphere surface were removed. Periodically, the 
spheres were rotated to provide equal time for each size 
at each position. 

Although the low fly population precluded sub- 
stantial fly captures, the results (Table 1) do nonethe- 
less indicate a consistent pattern of greater captures of 
females on 8 cm spheres than on spheres 10 cm or 
larger in size. Other recent studies we have carried out 
indicate that apple maggot female response to fruit of 
different sizes is partly under genetic control and partly 
a learned response based on recent experience with 
fruit of a particular size. From our results here, it 
appears that if an apple or a red sphere mimicking an 
apple is larger than 8 cm, neither genetic-based nor 
learned behavior of females confers strong attraction. 



cm size. 



Table 1. Total apple maggot females captured on unbaited sticky red 
spheres of different sizes hung in unsp rayed fruiting apple trees (July 27- 
August 8, 1989). 



Size of 








sphere (cm)* 


Experiment 1 


Experiment 2 


Experiment 3 


8 


7 a 


9 a 


11 a 


10 


b 


7 ab 


8a 


14 


1 b 


3b 


- 


18 


1 b 


- 


- 


23 


Ob 


- 


- 



•No. replicates per experiment: Expt. 1 = 5; Expt. 2 = 8; Expt. 3=8. Values 
not followed by the same letter are significantly different at odds of 19 to 
1. 



18 



FmU Notes, Fall, 1989 



Perhaps apples and red spheres increasingly larger 
than 8 cm decreasingly have the appearance of fruit in 
the eyes of flies whose native host is hawthorn fruit, 
which are only 1.5 to 2.0 cm in diameter. 

The second study involved evaluation of different 
numbers of vials containing synthetic apple odor 
placed at different distances from 8 cm sticky red 
spheres. At the New York Agricultural Experiment 
Station in Geneva, where Anne Averill, Harvey Reis- 
sig, Wendell Roelofs, and others showed butyl hex- 
anoate to be the principal component of apple odor 
attraction to apple maggot flies, liquid butyl hexanoate 
has been used to monitor fly populations by putting it 
into small (2-dram) polyethylene vials seated in wells 
drilled into 8 cm red spheres. The liquid is absorbed by 
the wall of the vial, which then releases about 700 apple 
equivalents of the odor per hour. In the first 2 years of 
our pilot second-stage apple IPM program, we placed 
such a polyethylene vial containing butyl hexanoate 
about 15 cm to the side of each 8 cm sticky red sphere 
hung on perimeter apple trees. However, recent re- 
search conducted by graduate student Martin Aluja of 
our laboratory suggested that a polyethylene vial re- 



Table 2. Total apple maggot females captured on 8 cm 
sticky red spheres hung in fruiting apple trees in a com- 
mercial orchard and baited with different numbers of 2- 
dram polyethylene vials containing attractive apple odor 
(butyl hexanoate) at different distances from the side of a 
sphere (July 21 - August 3, 1989). 



Distance of vials 
from sphere (cm)* 



Number of vials around each sphere 



15 



30 



60 



47 b 70 b 92 b 78 b 



67 b 66 b 149 a 92 b 



70 b 83 b 96 b 101 b 



leasing 700 apple equivalents of butyl hexanoate per 
hour may arrest or even repel apple maggot flies that 
move too close to the vial. We were therefore interested 
in determining the optimum density and distribution 
of polyethylene vials (containing butyl hexanoate) that 
would confer high fly attraction to the vicinity of a red 
sphere but not adversely affect the propensity of an 
arriving female to alight on the sphere. 

Our test was carried out in Clarkdale Orchard, 
West Deerfield, MA, which harbored a moderate popu- 
lation of apple maggot flies on a mixture of Early 
Mcintosh and Gravenstein test trees. We placed no 
more than 1 sphere in each tree. Using wire, we posi- 
tioned either 0,1,2, or 4 2-dram polyethylene vials of 
butyl hexanoate 15,30, or 60 cm to the side of a sphere. 
Where more than 1 vial per sphere was used, vials were 
distributed evenly around the sphere. Periodically, the 
vials were rotated from tree to tree to provide equal 
time for each treatment at each position. 

The results (Table 2) indicate that 2 vials of odor 
placed 30 cm to the side of a red sphere gave rise to a 
50% greater capture of apple maggot females than vials 
at any other density or distribution. Use of 2 or 4 vials 
per sphere invariably led to greater fe- 
male captures than vials or 1 vial at an 
equivalent distance. Thus, butyl hex- 
anoate used in conjunction with red 
spheres led to increased capture of apple 
maggot females, but too great an amount 
too close to a sphere reduced fly captures, 
possibly through arresting or repelling ef- 
fects. 

For future employment of red 
spheres to intercept apple maggot flies on 
perimeter apple trees under second-stage 
IPM, we will continue to use 8 cm spheres 
but will now bait each sphere with two 2- 
dram polyetheylene vials of butyl hex- 
anoate 30 cm from (and on opposite sides 
of) each sphere, instead of a single vial 15 
cm from a sphere. 



• Four replicates per treatment type. Values not followed 
by the same letter are significantly different at odds of 19 
to 1. 



ACKNOWLEDGMENT. We thank 
the Northeast Regional Project on Inte- 
grated Management of Apple Pests (NE- 
156) for supporting this work. 



•X* ^Sa 4* ^* »Sa 
^» 0^ ^* •{* «{* 



Fruit Notes, Fall, 1989 



19 




Fruit Notes 

University of Massachusetts 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

Amherst, MA 01003 



Nonprofit Organization 
U.S. Postage Paid 

Permit No. 2 
Amherst. MA 01 002 




FN 



01003 



Account No. 3-20685