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Full text of "Fruit notes"

l^j^H University of 
^^gk Massachusetts 
UMASS Amherst 

Library 



BIOLOGICAL 

OCT 2 5 1999 

SQtgNCES LIBRARY 



UM/Morr. 

Per 

SB 

354 

F68 



^"ruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

UMass Extension, U. S. Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R. Autio and William J. Bramlage 




Volume 62,'Q|^mber 1 
WINTER ISSUE, 1997 

Table of Contents 

Positioning Unbaited Pyramid 
Traps to Capture Plum Curculios 

How Do Plum Curculios Approach 
Host Trees and Pjrramid Traps? 

Do Natural Sources of Odor Enhance 
Plum Curculio Attraction to Traps? 

Petal Fall is the Most Attractive Developmental Stage 
of Mcintosh Apple Trees to Plum Curculio Adults 

Jim Anderson Dies 

Peach Cultivar Trials: Observations and Comments 

Agri-Mek: A 1996 Field Trial in a Commercial Apple Orchard 



Fruit Notes 



Publication Information: 

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

The costs of subscriptions to Fruit Notes are $ 1 0.00 for United States 
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begins January 1 and ends December 3 1 . Some back issues are available 
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ments 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 01 003 



UMASS 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 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 hy UMass Exlensuiii, Riihcil C, Hel^eseit. Director, in fiirlheraiice of the iicls of May 8 iindJune 30, 
1914. UMaas Extension offers equal opportunity in programs and employment. 



Positioning Unbailed Pyramid Traps 
to Capture Plum Curculios 

Ronald Prokopy and Starker Wright 

Department of Entomology, University of Massachusetts 



In the 1996 Winter issue of Fruit Notes, we 
reported results of our 1995 research on plum 
curculio responses to unbaited "Tedders" traps. 
These traps are pjrramidal in shape, dark in 
color, and are placed on the ground. They 
capture curculios that arrive on the trap 
surface and subsequently crawl upward to the 
tip, where they enter an inverted screen funnel 
(a cotton boll weevil trap top) placed over the 
tip, from which they cannot escape. 

All reported tests to date using Tedders 
traps (hereafter referred to as pyramid traps) 
for capturing plum curculios have involved 
deploying unbaited traps between canopies of 
apple trees within rows. In 1996, we evaluated 
unbaited pyramid traps at four different 
positions on the ground in a small commercial 
apple orchard (Prokopy orchard) in Conway, 
MA. In addition, we compared curculio 
captures by pyramid traps with captures by 
unbaited cotton boll weevil trap tops placed in 
tree canopies. For each position or type of trap, 
we compared daily trap captures with daily 
incidence of orchard fruit scarring by plum 
curculios. 

Materials & Methods 

Each pyramid trap was black and measured 
40 inches in vertical height, 22 inches in base 
width, and 2 inches in top width. Each was 
staked to the ground to prevent toppling by 
wind. All traps were constructed from plywood 
in our laboratory, but beginning in 1997, traps 
of essentially identical type can be purchased 
from Gemplers Inc., Mt. Horeb, WI (only known 
supplier). 

The orchard consisted of ten rows of five 
trees per row. Tree trunks were 20 feet apart 
between rows and 13 feet apart within rows. 



Trees were about 12 feet tall and about 10 feet 
in canopy diameter. Soil beneath tree canopies 
was treated with glyphosate in April and was 
devoid of vegetation throughout our study. The 
remainder of the orchard floor was covered with 
grass, which was maintained at a height of 2 to 
4 inches. Dense woods, which we considered to 
be prime overwintering habitat for plum 
curculios, lay about 25 feet north of the end tree 
of each row, and a large open field of grass lay 
immediately south. 

At the pink stage of bud development, 
pyramid traps were placed in association with 
each of the trees in the second through ninth 
rows (Figure 1). One trap was placed 10 feet 
north of the trunk of the northernmost tree (15 
feet from the woods), one trap 10 feet south of 
the trunk of the southernmost tree of a row (at 
the edge of the open field), one trap mid-way 
between the canopies of the northernmost and 
next northernmost tree of a row, and one trap 1 
foot from the trunk of the center tree of a row. 
At the same time, a boll weevil trap top was 
placed on the cut end of a 4-inch upright twig in 
the upper part of northernmost trees in the 
second through ninth rows. 

Traps were examined daily at 7 AM from 
time of installation (May 14) until four weeks 
after petal fall (June 27). In addition to 
recording numbers of curculios captured each 
day, we also recorded daily (from full bloom on 
May 23 until June 15) the number of fruit 
receiving a curculio feeding or oviposition scar 
in samples of five fruit per tree per day (200 
fruit per day among 40 trees). 

Orchard trees received no insecticide before 
bloom but were treated with phosmet on May 
28 (80% petal fall) and on June 15. All traps 
were removed during treatment, which was 
applied by a motorized back pack sprayer to the 



Fruit Notes, Volume 62 (Number 1), Fall, 1997 



1 Woods J 


c ,f 


15ft 



-N 



0000© 

* 0*0000 

* 00000 

* 00000 
' 00000 

* 00000 

* 00000 

* 00000 
00000 



Field 



Figure 1. Pyramid-trap deplo5rment in this experiment in 
relation to tree location. 



Table 1. Numbers of plum curculios captured by pyramids capped by boll 
weevil trap tops or by boll weevil trap tops alone at different locations in 
a small commercial apple orchard, May 14-June 27, 1996, Conway, MA. 



Trap type 



Trap location 



Average number 
per trap* 



PjTamid 
Pyramid 
Pyramid 
P5Tamid 
Trap top alone 



Apple tree trunk 6.0a 

Between apple tree canopies 0.8b 

Between apple trees and woods 1.1b 

Between apple trees and open field 1.1b 

Apple tree canopy 0.4b 



'Numbers followed by a different letter are significantly different at odds 
of 19:1. 



Fruit Notes, Vol 



ume 62 (Number 1), Winter, 1997 



12 - 



10 ■ 



E 

z 



■ Scars 

D Captured Adults 

♦ Insecticide Application 



r M I 



6-Jun 8-Jun 



10-Ju 



12-Jun 14-Jun 



23-May 25-May 27-May 29-May 31 -May 2-Jun 4-Jun 

Figure 2. Egg-laying scars and trap captures from May 23 through June 15, 1996. 



tree canopy and trunks. 
Results 

Unbaited pyramid traps placed adjacent to 
tree trunks captured at least five times more 
curculios than unbaited pyramid traps at any 
other position and 15 times more curculios than 
unbaited boll weevil trap tops placed in tree 
canopies (Table 1). 

Capture of substantial numbers of curculios 
by unbaited pjn-amid traps next to tree trunks 
could entice one to believe that such captures 
might be used as a basis for determining need 
for and timing of insecticide sprays against 
curculio. Unfortunately, this did not prove to be 
the case in the Conway orchard in 1996. In fact, 
there was no trap position for which there was 
even a faint positive correlation between daily 



trap captures and daily numbers of sampled 
fruit injured by plum curculios. Indeed, the 
correlation between daily captures by pyramid 
traps at tree trunks and daily fruit injuries was 
a negative rather than a positive one (Figure 2). 
In other words, during periods when captures 
were greatest, injury was least. 

Conclusions 

Our findings show that placing black 
pyramid traps next to apple tree trunks is the 
most effective position in terms of capturing the 
greatest numbers of plum curculios in an apple 
orchard. Results of additional studies (see 
following article) indicate that the principal 
reason why this position is better than any 
other position stems from the strong tendency 
of curculios, when crawling, to move toward 



Fruit Notes, Volume 62 (Number 1), Fall, 1997 



areas of greatest darkness within an orchard 
(that is, toward tree trunks). Placement of 
black pyramid traps next to tree trunks 
capitalizes on this behavioral tendency, which 
is expressed just as strongly in an understory of 
vegetation as on bare ground. 

Even at this most favored tree-trunk 
position, however, unbaited black p5Tamid 
traps fall well short of being an effective means 
of monitoring the occurrence of curculio injury 
to apples. Additional studies (see following 
article) indicate that a principal cause for the 
failure of captures by unbaited pyramid traps 
on ground to be good predictors of fruit injury in 
tree canopies lies in the means by which 
curculios approach pjrramid traps and ap- 
proach tree canopies: by crawling or by flight. 
Evidence suggests that during warm weather, 
curculios may enter tree canopies directly by 
flight, bypassing tree trunks and pjrramid 
traps. Injury to fruit is greatest during periods 
of warm weather, such as occurred from June 5 
through June 9 in the Conway orchard in 1996 



(Figure 2). It appears that during this time 
period, most curculios arrived in tree canopies 
by flight and not by crawling up tree trunks (or 
up pyramid traps). 

What might be a solution to this 
shortcoming of pyramid traps during warm 
weather? One solution might be to use a 
powerful attractive odor in conjunction with a 
pyramid trap positioned next to a tree trunk 
(see following articles). Another solution might 
be to develop an effective odor-baited trap for 
use in the tree canopy. We are working toward 
both solutions. 



Acknowledgments 

This work was supported by grants from the 
USDA Northeast Regional IPM Competitive 
Grants Program, the USDA SARE Program, 
State/Federal IPM funds, and the New 
England Tree Fruit Growers Research Com- 
mittee. 



•Xa •Xa *1> vl* vL* 

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Fruit Notes, Volume 62 (Number 1), Winter, 1997 



How Do Plum Curculios Approach 
Host Trees and Pyramid Traps? 

Ronald Prokopy and Starker Wright 

Department of Entomology, University of Massachusetts 



The means by which plum curcuhos 
approach host trees, whether by flight or by 
crawhng, can provide important background 
information leading toward optimization of 
design and location of traps for monitoring and 
possibly even controlling curculios. We report 
here on several studies conducted during 1996 
aimed at learning more about movement 
patterns of curculios toward host trees and 
pyramid traps under varying sorts of weather 
conditions. 

Experiments & Results 

Movement Toward Host Trees. In our 

first experiment in a small unmanaged orchard 
of 36 semi-dwarf trees owned by Hardigg 
Industries of South Deerfield, MA, we wanted 
to determine whether curculios entered the tree 
by flying, by crawling, or by both means, and 
whether mode of entry depended on weather 
conditions. We coated the trunks of 12 trees 
(every third tree) with a thick 1-inch-wide band 
of Tangletrap about 2 feet above ground to 
prevent curculios fi-om crawling up the trunk 
and into the canopy. Direct observation of 
curculios attempting to cross this sticky band 
indicated that they were unsuccessful in doing 
so. None of the tips of branches of these or any 
other trees in the orchard reached closer than 2 
feet above ground, thereby precluding curculios 
from crawling onto branch trips to reach the 
canopy. Height of grass was maintained below 
4 inches. Another set of 12 trees (every third 
tree) was not treated with Tangletrap to permit 
curculio arrival both by crawling and by flight. 
Every evening at 8 PM from May 19 (full bloom) 
to June 7, we tapped the branches of each of 
these 24 trees over white cloth sheets placed on 
the ground beneath the canopy and collected all 



fallen curculios. We also obtained an hourly 
record of temperature at a nearby location for 
each day from May 19 to June 7. 

Results (Table 1, experiment 1) show that 
that total number of curculios collected fi^om 
trees having a band of Tangletrap was nearly 
equal to that of trees without a band of 
Tangletrap. Results (Table 1, experiment 1) 
also show there was a significant positive 
correlation between daily numbers tapped from 
trees having a Tangletrap band, as well as from 
trees without Tangletrap, and daily high 
temperature. 

These results provide two valuable pieces of 
information. First, a band of Tangletrap 
around the tree trunk is of no apparent value in 
preventing curculios from accessing host trees 
and causing injury to fruit. One reason for this 
lack of deterring effect may be that those 
curculios which crawl up tree trunks and are 
unable to pass beyond a sticky barrier 
subsequently fly into the tree canopy, provided 
the temperature is warm enough to permit 
flight. We did, in fact, observe directly some 
curculios behaving in this manner on warm 
days. Second, our prediction at the outset that 
numbers of curculios in tree canopies would be 
equal on trees with and without a Tangletrap 
band on warm days (signifying movement into 
canopies largely or solely by flight) but would be 
greater on trees without than with a 
Tangletrap band on cool days (signifying 
movement into canopies largely solely by 
crawling) was not supported by the data. On 
warm days, numbers were large on both types 
of trees, indicating that curculios were prone to 
fly into tree canopies on warm days. On cool 
days, numbers were few on both types of trees, 
indicating little tendency of curculios either to 
fly or to crawl into trees on cool days. 



Fruit Notes, Volume 62 (Number 1), Fall, 1997 



Table 1. Numbers of plum curculios found in daily collections at 8PM in each of three 
experiments in Hardigg's unmanaged orchard, May 19 - June 7, 1996, South Deerfield, MA. 


Number of 
Exp. Treatment replicates 


Average 
number of 
curculios* 


Value of 
correlation 

with 
temperature 


1 Trees with a Tangletrap band 12 
Trees without a Tangletrap band 12 

2 Clear Plexiglas, low position 12 
Clear Plexiglas, high position 12 

3 Pyramid traps with a Tangletrap band 6 
P3rramid traps without a Tangletrap band 6 


100a 
107a 

16a 
14a 

7b 
20a 


0.56 
0.46 

0.43 
0.48 

0.73 
0.39 


*Numbers in each experiment followed by a different letter are significantly different at 
odds of 19:1. 

**A perfect positive correlation between daily numbers of curculios found in each treatment 
and daily high temperature would be 1.00. Each correlation value shown here (except 
P5Tamid traps without Tangletrap) indicates a significant positive relation at odds of 19:1. 



In our second experiment, conducted in the 
same orchard, we wanted to gain more direct 
information on the extent of curculio flight into 
tree canopies on warm versus cool days. 
Therefore, on the remaining 12 trees in the 
orchard (every third tree not involved in the 
first experiment), we positioned two squares of 
clear Plexiglass (2 feet by 2 feet) vertically on a 
pole about 2 feet to the outside of the perimeter 
foliage of each tree: one square at base height of 
foliage and one square at top height of foliage. 
The entire surface of each square facing away 
from the canopy (but not the surface facing 
toward the canopy) was coated with Tangletrap 
to capture curculios flying toward the canopy. 
Traps were emplaced on the same dates and 
examined for captured curculios at the same 
time (daily at 8 PM) as in the first experiment. 

Results (Table 1, experiment 2) show that 
there was no significant difi'erence in numbers 
of captured curculios between the low- 
positioned and the high-positioned traps. 
Results (Table 1, experiment 2) also show there 
was a significant positive correlation between 



daily numbers captured at each position and 
daily high temperature. Furthermore, there 
were significant positive correlations between 
daily captures on high or low traps and daily 
numbers of curculios tapped from canopies of 
trees with or without a Tangletrap band (data 
not shown). 

Together, these findings constitute strong 
evidence that on warm days, curculios fly 
directly into tree canopies, whereas on cool days 
there is much less tendency to do so. 

Movement Toward Pyramid Traps. In 
our first experiment, we placed an unbaited 
pyramid trap midway between the trunk and 
canopy edge of each of the 12 trees that received 
sticky-coated squares of Plexiglas at the 
Hardigg orchard. Every other pyramid trap 
received a band of Tangletrap 4 inches above 
the base to prevent curculios from crawling to 
the top. The remaining six traps did not receive 
Tangletrap. All traps were in place fi"om May 
25 to June 7 and were examined daily at 8 PM 
for captured curculios. 

Results (Table 1, experiment 3) show that 



Fruit Notes, Volume 62 (Number 1), Winter, 1997 



traps with Tangletrap captured about one- 
third as many curculios as traps without 
Tangletrap, signifying that about two-thirds of 
the curcuHos captured by traps without 
Tangletrap arrived on the traps by crawling 
onto them rather than by flying onto them. 

As with crawling curculios that encoun- 
tered a Tangletrap band at the base of a tree 
trunk, crawling curculios that encountered a 
Tangletrap band at the base of a pyramid trap 
likewise subsequently may have taken flight, 
temperature permitting. Such flight appar- 
ently did not result in landing on the middle or 
upper part of a pyramid trap, however. Results 
(Table 1, experiment 3) also show there was a 
significant positive correlation between daily 
numbers captured by pyramid traps with 
Tangletrap (but not traps without Tangletrap) 
and daily high temperature. 

In our second experiment, conducted in 
association with three large unmanaged trees 
near Prokopy's home in Conway, we studied in 
greater depth curculio captures by unbaited 
pyramid traps that received a band of 
Tangletrap at the base and traps that did not. 
In all, there were two traps of each type 
beneath each tree, midway between the trunk 
and edge of canopy. Grass beneath each tree 
was maintained below 4 inches in height. 
Captured curculios were counted daily at 5AM 
and 10PM from June 29 to July 14. 

Results (Table 2) show that across the 
entire 24-hour period of a day, traps with 



Tangletrap captured about one-third as many 
curculios as traps without Tangletrap, corrobo- 
rating results of the preceding experiment at 
Hardigg. Interestingly, traps without 

Tangletrap captured about twice as many 
curculios from SAM to 10PM as fi-om 10PM to 
SAM, whereas traps with Tangletrap captured 
more than 20 times as many curculios fi*om 
SAM to 10PM as from 10PM to SAM. These 
results signify that about twice as many 
curculios arrive on pjrramid traps during 
daylight as during darkness, that about half of 
those arriving on pyramid traps during 
daylight do so by flying and half by crawling, 
and that almost all of those arriving on pyramid 
traps during darkness do so by crawling. There 
may be two reasons why very few curculios fly 
onto pyramid traps during darkness: first, on 
most nights, temperature during darkness may 
be too cool to permit flight; and second, 
curculios in flight during darkness may be 
unable to see pyramid traps. 

In our third experiment, beneath a plum 
tree at Prokopy's in Conway, we released a 
group of 40 field-collected plum curculios on the 
ground mid-way between the tree trunk and 
edge of the canopy. We did this on 12 evenings 
at 7:30 PM between June 22 and July 14 when 
the temperature was about 70°F and there was 
no rain falling. Four of the releases were made 
north of the tree on ground covered by 4 inches 
of grass, four north of the tree on bare ground 
(the grass was covered with soil), and four south 



Table 2. Numbers of plum curculios captured by pyramid traps beneath 
unmanaged apple trees at different times of day, June 29 - July 14, 1996, 
Conway, MA. 



Traps 



Number of 
replicates 



Average number captured* 



SAM - 10PM 10PM - S AM 



With a band of Tangletrap 6 

Without a band of Tangletrap 6 



4.3b 
7.8a 



0.2c 
3.Sb 



^Numbers followed by a different letter are significantly different at odds of 
19:1. 



Fruit Notes, Volume 62 (Number 1), Fall, 1997 



of the tree on bare ground. We placed one 
unbaited pyramid trap next to the tree trunk 
and one at the north edge of the canopy (when 
releases were north) or south edge of the canopy 
(when releases were south). 

Results revealed that about 20% of released 
curculios were captured by the trap at the 
trunk and about 4% by the trap at the edge of 
the canopy, irrespective of where released. 
Further results revealed that of all released 
curculios, about 15% eventually flew into the 
tree canopy, about 15% flew toward open space, 
about 1% flew onto the tree trunk, about 2% 
flew onto the trunk trap, and about 1% flew 
onto the edge trap. Interestingly, about 40% of 
released curculios crawled toward the tree 
trunk, with no more than 4% crawling in any 
other direction. This was true irrespective of 
whether curculios were released north or south 
of the tree trunk. 

These results support results reported in a 
preceding article in this issue showing that 
several times more curculios were captured by 
pyramid traps next to tree trunks than by 
pjrramid traps more distant from tree trunks. 
Results here also indicate that when evening 
temperatures are moderate (somewhat condu- 
cive to flight but not highly so), only a very 
small proportion of curculios that does fly 
alights on pyramid traps. The great majority in 
flight bypasses the traps. On the other hand, a 
very high proportion of crawling curculios 
moves toward the tree trunk, where they 
encounter and ascend either the tree trunk or 
an adjacent pyramid trap. 

Conclusions 

Perhaps the most important general 



conclusion from this array of studies is that 
when temperature is high enough to permit 
plum curculio flight, curculios may fly directly 
into tree canopies (either from overwintering 
sites or from ground beneath trees). In so 
doing, it appears that most are likely to bypass 
unbaited pyramid traps, irrespective of trap 
location. Unbaited pyramid traps, especially 
when located next to tree trunks, appear to be 
very good at capturing curculios that are 
crawling toward the greatest area of darkness 
in the habitat (that is, toward the center of the 
tree). Substantial numbers of curculios appear 
to crawl toward tree trunks and adjacent 
pjrramid traps when temperatures are too low 
and/or the amount of light is too little to permit 
flight. Hence, unbaited pyramid traps at tree 
trunks may afford an accurate representation 
of curculio populations in orchard trees during 
periods that favor curculio arrival in trees by 
crawling but not during periods that favor 
curculio arrival in trees by flight. Overall, as 
shown here, a band of Tangletrap around the 
tree trunk is of little value in preventing 
curculios from achieving substantial numbers 
in tree canopies. 



Acknowledgments 

This work was supported by grants from the 
USDA Northeast Regional IPM Competitive 
Grants Program, the USDA SARE Program, 
the New England Tree Fruit Growers Research 
Committee, and State/Federal IPM funds. We 
thank Jim Hardigg of South Deerfield, MA for 
permission to work in his orchard. 



*X* *X» *X* *X* *X* 

•^ #^ #^ #y* #^ 



Fruit Notes, Volume 62 (Number 1), Winter, 1997 



Do Natural Sources of Odor Enhance 
Plum Curcullo Attraction to Traps? 

Ronald Prokopy and Tracy Leskey 

Department of Entomology, University of Massachusetts 



In a preceding article in this issue of Fruit 
Notes, we suggested that addition of a powerful 
attractive odor might enhance the capturing 
power of a pyramid or cone trap to an extent 
that such a trap could become reliable for 
monitoring the abundance of plum curculios in 
commercial orchards. Here, we report on 1996 
tests in which we evaluated plum curculio 
males, plum curculio females, whole stored 
mature apples, pieces of stored mature apples, 
and fresh immature apples as potential natural 
sources of attractive odor for plum curculios. 
We also evaluated ammonium carbonate (an 
attractant for apple maggot flies) as a potential 
attractant for plum curculios. 

Experiments & Results 

Curculios as Odor Sources. Curculios 



used as odor sources were separated by sex 
shortly after emergence in summer and then 
were held over winter in containers outdoors 
until ready for use here. For each experiment, 
they were confined in a plastic container in 
groups of 20 same-sex individuals per 
container. Each container was cylindrical, 
about 2 inches in diameter and 3 inches tall, 
covered at the top with a clear-plastic lid to 
prevent entry of rainfall, and covered at the 
bottom with window screen to allow odor to 
emanate from the cylinder. Each cylinder, 
including "check" cylinders containing no 
curculios, received eight fresh-picked imma- 
ture apples (about 1/2 inch diameter), removed 
every other day. Traps with which these 
containers were associated were examined 
daily at 5 AM, at which time captured curculios 
were removed. On average, 15 of the 20 



Table 1. 


Mean numbers of plum curculios 


captured per day in traps baited 


with either male, female, or no 


plum curculios. 












Average number 




Location of 


Bait 


Number of 


captured 


Exp. 


bait containers 


source 


replicates 


per day 


1 


Base of pjTamid trap 


Males 


27 


4.9a 






Females 


27 


4.5a 






None 


27 


6.2a 


2 


Top of pyramid trap 


Males 


8 


3.8a 






Females 


8 


1.9a 






None 


8 


5.1a 


3 


On boll weevil 


Males 


15 


0.2a 




trap tops on twigs 


Females 


15 


0.6a 




in tree canopy 


None 


15 


0.4a 


*In each 


I experiment, numbers followed by s 


I different letter are significantly 


different at odds of 19:1. 






1 



Fruit Notes, Volume 62 (Number 1), FalJ, 1997 



curculios per container remained alive during 
the course of an experiment. 

In the first experiment, three containers of 
same-sex curcuhos were attached 8 inches 
above ground to the wings of pyramid traps, 
one container per wing. Traps were placed mid- 
way between trunks and perimeters of 
unmanaged apple trees from May 23 (full 
bloom) until June 12. Results (Table 1) show 
that traps baited with "check" containers 
devoid of curculios captured similar numbers of 
curculios than traps baited with live males or 
live females. 

In the second experiment, one container of 
curculios was affixed to an open-trap boll weevil 
trap top capping a p5rramid trap in such a way 
that odor could move fi"om the container of 
curculios through the boll weevil trap top and 
down onto the pyramid. Traps were placed 
mid-way between trunks and perimeters of 
unmanaged apple trees from June 13 until 
June 21. Results (Table 1) show that traps 
baited with "check" containers devoid of 
curculios captured similar number of curculios 
than traps baited with live males or females. 

In the third experiment, one container of 



curculios was affixed to a boll weevil trap top in 
the same manner as in the second experiment. 
Then, each was placed on the end of an upright 
twig at mid-height in the canopy of an 
unmanaged apple tree from May 23 until June 
21. Results (Table 1) show that few plum 
curculios were captured by any of the traps, 
with no significant differences in captures 
among traps baited with males, females, or 
empty traps. 

Apples as Odor Sources. Apples used as 
odor sources were either mature Fuji apples 
stored over winter under refrigeration and 
washed thoroughly before use or immature 
Mcintosh apples (about 2/3 inch diameter) 
attached to freshly cut unsprayed branchlets. 

In the first experiment, 16 whole mature 
Fuji apples were distributed evenly on the 
ground at the base of each pyramid trap. Traps 
were placed mid-way between trunks and 
perimeters of unsprayed apple trees from May 
21 (early bloom) until June 1. Results (Table 2) 
show no enhancement of trap captures by 
additions of whole mature apples at bases of 
pyramid traps. 

In the second experiment, a 2-inch wedge 



Table 2. Mean numbers of plum curculios captured per day 
immature apples or unbaited traps. 


in traps baited with mature or 


Exp. 


Location of bait 




Bait source 


Number of 
replicates 


Average number 

captured 

per day 


1 
2 
3 


Base of pyramid trap 

Boll weevil trap top 
capping pyramid trap 

Base of pjTamid trap 


Whole mature 

Fuji apples 

Unbaited 

Wedge of mature 
Fuji apple 
Unbaited 

Branchlets bearing 

immature Mcintosh apples 

Unbaited 


12 
12 
24 
24 
16 
16 


2.0a 
2.5a 
1.5a 
2.2a 
4.3a 
6.0a 


*In each experiment, numbers followed by a different letter are signifi 
odds of 19:1. 


cantly different at 



10 



Fruit Notes, volume 62 (Number 1), Winter, 1997 



cut from a mature Fuji apple was placed inside 
a boll weevil trap top capping a pyramid trap in 
a way that odor could move down onto the 
pyramid. Wedges were renewed daily. Traps 
were placed mid-way between trunks and 
perimeters of unmanaged apple trees from 
June 3 until June 9. Results (Table 2) show no 
enhancement of trap captures by additions of 
apple wedges to boll weevil trap tops capping 
pyramid traps. 

In the third experiment, 4 branchlets (each 
with 12 Mcintosh apples) were distributed 
evenly on the ground at the base of each 
pyramid trap. Traps were placed mid-way 
between trunks and perimeters of unmanaged 
apple trees from June 15-22. Results (Table 3) 
show no enhancement of trap captures by 
additions of fresh-cut branchlets bearing 
immature apples at bases of pyramid traps. 

Ammonium Carbonate as Odor Source. 
Ammonium carbonate crystals were distrib- 
uted so as to cover screen bases of cylindrical 
containers of the type previously described for 
housing live plum curculios. 

In the first experiment, three containers of 
ammonium carbonate were attached 8 inches 
above ground to the wings of each pyramid 
trap, one container per wing. Traps were 
placed adjacent to trunks of unmanaged trees 
from June 22 until June 24. Results (Table 3) 
show that ammonium carbonate did not 
enhance trap captures. 



In the second experiment, a container of 
ammonium carbonate was affixed to an open- 
top boll weevil trap top capping a pjTamid trap 
in such a way that odor could move from the 
container through the boll weevil trap top and 
down onto the p3nramid. Traps were placed 
adjacent trunks of unmanaged trees from June 
24 until June 26. Results (Table 3) show that 
ammonium carbonate had a significantly 
negative effect on trap captures. 

Conclusions 

Disappointingly, none of the sources of odor 
we evaluated led to an increase in numbers of 
plum curculios captured, either by pyramid 
traps placed on the ground beneath tree 
canopies or boll weevil trap tops placed within 
tree canopies. What might have been some 
causes of this lack of positive response of 
curculios to odor baits evaluated in conjunction 
with traps? 

In the case of male or female curculios as 
bait, we were quite puzzled by results until we 
carried out some additional laboratory tests. 
The way in which we conducted our field tests 
was consistent with the way tests of potential 
odor attractancy of one sex of insect to another 
is normally evaluated in the field. We fully 
expected to find that odor of male or female 
curculios was attractive to individuals of the 
same or opposite sex. This expectation was 



Table 3. Mean numbers of plum curculios captured per day in traps baited 
with ammonium carbonate (AC). 











Average number 




Location of 


Bait 


Number of 


captured 


Exp. 


bait containers 


source 


replicates 


per day 


1 


Base of pyramid trap 


AC 


8 


1.6a 






None 


8 


2.3a 


2 


Top of pjTamid trap 


AC 


8 


1.4b 






None 


8 


5.0a 



*In each experiment, numbers followed by a different letter are 
significantly different at odds of 19:1. 



Fruit Notes, Volume 62 (Number 1), FaU, 1997 



11 



heightened part-way through our field tests 
when a pubhcation appeared by chemists in 
Ilhnois detaihng the chemical structure of a 
pheromone (grandisoic acid) produced by male 
plum curculios that is equally attractive to both 
females and males, even when used in small 
amounts. This was indeed exciting news. Our 
follow-up laboratory tests showed, however, 
that when curculios are confined to small areas 
(such as the containers we used for curculios as 
odor sources), they emit stress sounds and/or 
odors alerting other curculios. These sounds or 
odors apparently mask or outweigh the luring 
power of attractive pheromone. This suggests 
that the most rewarding way to evaluate 
pheromonal odor in conjunction with traps in 
the field would be to use synthetic pheromone 
rather than a natural source of pheromonal 
odor. 

In the case of apple odor as bait, it appears 



that if natural sources of odor are used in the 
amounts evaluated here, either such an 
amount is insufficient to compete with fruit 
odor sources on adjacent trees, or natural 
sources of apple odor lose attractiveness (odor 
composition changes) rapidly after employ- 
ment. As with synthetic sex pheromones, 
sjrnthetic apple odor hopefully will become an 
effective alternative to natural sources of apple 
odor for attracting plum curculios to traps (see 
following article). 



Acknowledgments 

This work was supported by grants from the 
USDA Northeast Regional IPM Competitive 
Grants Program, State/Federal IPM funds, the 
USDA SAKE Program, and the New England 
Tree Fruit Growers Research Committee. 



•Xa •^Ia *X* *X* *1^ 
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12 



Fruit Notes, Volume 62 (Number 1), Winter, 1997 



Petal Fall is the Most Attractive 
Development Stage of Mcintosh 
Apple Trees to Plum Curculio Adults 

Tracy LeskeyS Michele Bakis^ Holly Gagne^ Larry Phelan^, 

and Ronald Prokopy^ 

^Department of Entomology^ University of Massachusetts 

^Ohio Agricultural Research & Development Center, Ohio State 

University 



In the 1996 winter issue oi Fruit Notes, we 
reported the results of laboratory assays 
conducted in 1995 aimed in part at examining 
plum curculio responses to odors emitted from 
Mcintosh apple trees. We obtained some 
evidence indicating that attractive volatiles 
were emitted from all parts of Mcintosh trees 
(not just fruit) and were emitted in the most 
attractive form at petal fall. Here, we report on 
1996 laboratory bioassays of curculio responses 
to extracts of Mcintosh twigs, leaves, and fruit 
at eight different tree- developmental stages, 
using different solvents. 

Materials & Methods 

Hexane and water extracts were made from 
twigs, leaves, or fruit of Mcintosh at each of the 
following stages of development: pink, bloom, 
petal fall, and 2, 3, 4, 5, and 6 weeks after 
bloom. 

Curculios used in bioassays were collected 
from unsprayed wild plum and apple trees and 
sexed in the laboratory. For all tests, curculios 
were starved for 24 hours prior to testing. Tests 
were conducted at the beginning of darkness. 
One curculio was placed into each petri dish 
bioassay chamber and allowed to move toward 
odors emitted from a hexane or water extract of 
Mcintosh tissue (the treatment) or toward 
hexane or water alone (used as a control). 
Hexane was allowed to evaporate before testing 
and curculios were given 2 hours to respond. 



To measure the power of a Mcintosh odor 
extract to stimulate curculio response, we used 
a response index. The response index was 
calculated by subtracting the number of 
curculios responding to the control from the 
number responding to the treatment, dividing 
this amount by the total number of curculios 
tested, and multiplying by 100. The greater the 
value of the index, the more attractive was the 
Mcintosh odor extract. We consider an index of 
25 to be the minimum for suggesting 
attractiveness. 

Results 

Hexane extracts of Mcintosh twigs, leaves, 
or fruit at petal fall were more attractive than 
hexane extracts made at any other develop- 
mental stage (Figure 1). Hexane extracts of 
fruit at petal fall (index = 43) were similarly 
attractive to extracts of twigs or leaves at petal 
fall (index = 40 for each). These response indices 
are nearly identical to those recorded in 1995 
for curculio responses to hexane extracts of 
Mcintosh fruit, twigs, and leaves at petal fall. 
Finally, both males and females responded 
equally well to extracts made with hexane. 

Water extracts of Mcintosh twigs, leaves, or 
fruit at pink, petal fall, and two weeks after 
bloom were the most attractive developmental 
stages (Figure 2). At petal fall, extracts of 
Mcintosh fruit (index = 71) were slightly more 
attractive than extracts of Mcintosh twigs 



Fruit Notes, Volume 62 (Number 1), Fall, 1997 



13 




Bloom 



5 Wks 



6 Wks 



Figure 1. Response Indices for plum curculio adults during 2 hours of exposure to 
hexane extracts of twigs (diamonds), leaves (squares), or fruit (triangles) from 
Mcintosh trees at pink, bloom, petal fall, or 2, 3, 4, 5, or 6 weeks after bloom. If the 
difference between two means of any stage exceeds 16 (based on a sample size of 
12), then the means are significantly different at odds of 19 to 1. 



(index = 58), whereas extracts of Mcintosh 
leaves were marginally attractive (index = 25), 
most likely because the waxy layer on leaf 
surfaces prevented water from extracting 
volatile components. Again, both males and 
females responded equally well to extracts 
made with water. 

Conclusions 

From these results and from what we 
observed in 1995, we conclude that petal fall is 
the most attractive developmental stage of 
Mcintosh trees to plum curculio adults. 
Further, we believe that all Mcintosh plant 
tissues (twigs, leaves, and fruit) contain the 
attractive odor components at this time. These 
results further strengthen our hope that 
synthetic equivalents of these attractive 
Mcintosh plant odors can be identified and 



synthesized, providing tools to enhance trap 
effectiveness for monitoring and possibly even 
controlling plum curculios. Further, were 
believe that if synthetic host odors can be used 
in conjunction with synthetic male-produced 
pheromone identified in 1996 by Eller and 
Bartlett of Illinois, the curculio-capturing 
power of traps will be enhanced further. Our 
next step will be to examine curculio responses 
to host-plant odors used in combination with 
male-produced pheromone. 

Acknowledgments 

This work was supported by grants from the 
USDA Northeast Regional IPM Competitive 
Grants Program, the USDA SARE Program, 
State/Federal IPM funds, and the New 
England Tree Fruit Growers Research Com- 
mittee. 



14 



Fruit Notes, volume 62 (Number 1), Winter, 1997 




Wks 



Figure 2. Response Indices for plum curculio adults during 2 hours of exposure 
to water extracts of twigs (diamonds), leaves (squares), or fruit (triangles) from 
Mcintosh trees at pink, bloom, petal fall, or 2, 3, 4, 5, or 6 weeks after bloom. If 
the difference between two means of any stage exceeds 20 (based on a sample 
size of 12), then the means are significantly different at odds of 19 to 1. 



*sL^ *^ *^ *^ *^ 

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Fruit Notes, Volume 62 (Number 1), FaU, 1997 



15 



Jim Anderson Dies 



James F. Anderson, Emeritus Associate 
Professor of Pomology, passed away on 
February 8, 1997. Professor Anderson was 
born in Morgantown, West Virginia, and 
received his B.S. and M.S. degrees from the 
University of West Virginia. He served in the 
miUtary during World War II and participated 
in the Battle of the Bulge. 

Jim joined the faculty of the Pomology 
Department of Massachusetts Agricultural 
College in 1948 and retired from the 
Department of Plant & Soil Sciences of the 
University of Massachusetts in 1988. For 
many years Jim was involved in evaluation of 
new fruit cultivars, and he was expert at 
identifying fruit cultivars by their vegetative 
characteristics. However, his primary respon- 
sibility during these years was teaching, and he 
was honored by selection for a number of 
Outstanding Teacher Awards by the Stockbridge 
School students. 

In an^ interview at the time of his 
retirement, Jim said, 'Tou can't really learn 



about trees from books. You have to get out 
there with the trees." Many alums will 
remember their orchard pruning experiences 
with Jim in the dead of winter, because that is 
when the pruning is done. "But the students 
were all good about it; they never ambushed 
me," Jim said. "They'd know that I'd be out 
there in the cold with them." 

Jim leaves his wife, Edna (18 Wildwood 
Lane, Amherst, MA 01002). He also leaves his 
former colleagues, who are saddened by the loss 
of a true gentleman and friend, and by 
generations of alums who learned much more 
from him than was written in books. 

In memory of Professor Anderson's love of 
teaching, a memorial scholarship fund for 
students in Plant & Soil Sciences is being 
established. Anyone wishing to assist in this 
memorial to Jim may send a contribution to the 
Plant & Soil Sciences Scholarship Fund, c/o 
William J. Bramlage, French Hall, University 
of Massachusetts, Amherst, MA 01003. 



*sL» *X# *X* •A* *X» 

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16 



Fruit Notes, Volume 62 (Number 1), Winter, 1997 



Peach Cultivar Trials: 
Observations and Comments 

Karen I. Hauschild 

Department of Plant & Soil Sciences, University of Massachusetts 



In the Fall 1995 issue of Fruit Notes, I 
described and commented on the first plantings 
of peaches and nectarines in my cultivar trial at 
the University of Massachusetts Horticultural 
Research Center in Belchertown. Since 
another full growing season has passed, it 
seems appropriate to add to the information 
presented previously. 

Additionally, in the spring of 1996, 1 added 
three yellow-fleshed peaches, replaced three 
yellow-fleshed peaches ft-om the 1993 trial, 
added one white peach and replaced another, 
and added three white-fleshed nectarines. The 
peach cultivar trial now includes 20 yellow- 
fleshed peaches, 7 white-fleshed peaches, 6 
yellow-fleshed nectarines, and 3 white-fleshed 
nectarines. 

All cultivars planted prior to 1996 fruited in 
1996. Following is updated information on the 
cultivars that were planted in 1990, as well as 
initial observations of fruit from the 1993 and 
1994 plantings. I also will describe the 
cultivars that were planted in 1996. 

1990 Planting 

Yellow- fleshed Peaches 

Jerseydawn was very popular at the 
Horticultural Research Center in 1996. For an 
early fruit, the flavor in 1996 was excellent, size 
was good, and split pits occurred in only about 
20% of the crop. 

Redhaven. Size was not impressive this year, 
nor was flavor. There are several other 
cultivars in this harvest window that have 
better size and fruit quality than Redhaven. 

Salem fruit were very good to excellent in 1996. 
The flavor was excellent, size was good, and the 
fruit was very attractive. 



Flavorcrest fruit were very flavorful and had 
high quality in 1996. 

New Haven. Although fruit size in 1996 was 
some-what smaller than ideal, fruit quality was 
excellent. New Haven is a much better peach 
than Redhaven. 

Madison was an excellent peach. It had great 
peach flavor, was good size, and was attractive. 

Harrow Beauty was one of my favorites in 
1996. The fruit had good size and great peach 
flavor. 

Jim Dandee fruit size was not as impressive in 
1996 as it was in 1995, but the flavor of this 
peach was very good. 

Harcrest fruit were flavorful, had good size, 
and had very impressive quality in 1996. 

Fayette flavor was disappointing in 1996; 
however, it was a good late season cultivar. 

Encore may be too late for most growers, 
especially those who harvest large acreages of 
Mcintosh apples. It was a good peach for the 
late season. 

White-fleshed Peaches 

Summer Pearl fruit were not as flavorful in 
1996 as in previous years. Quality was good, 
and size was good. Fruit do not hold up well 
after harvest. 

Nectarines 

Earliscarlet fruit sized well and had excellent 
flavor. 

Fantasia sized well and had excellent flavor 
and color but ripened in mid-September, a 
problem for some growers. 
Summer Beaut was an excellent nectarine. 
Size was good, fruits were flavorful, and color 



Fruit Notes, Volume 62 (Number 1), FaU, 1997 



17 



was good where trees were open. 

1993 Planting 

Yellow-fleshed Peaches 

John Boy was a very large, flavorful peach. It 
was attractive, but did not have the best 
quality. Fruit were harvested a little late, 
which may have influenced quality. 

Sentry appeared to be a good peach, but 
further evaluations are required. 

White-fleshed Peaches 

Lady Nancy fruit were of good size and quality 
and very attractive. 

Red Rose fruit were medium in size and had 
good quality. 

1994 Planting 

White-fleshed Peaches 

White Lady trees bore a few fruit in 1996, but 
will reserve comment until next year. 

Sugar Lady trees also bore fruit for the first 
time in 1996. Fruit were good size and had 
reason-able quality. 

Nectarines 

Easternglo produced a few fruit in 1996. Color 
was excellent, but flavor was not great. 

Sunglo produced few fruit in 1996. Fruit had 
good size, good color, and good flavor. 

1996 Planting 

Descriptions below are based on catolog or 
on evaluations from other areas of the country. 

Yellow-fleshed Peaches 

PF-1 fruit ripen 20 days before Redhaven, are 



partial clingstone, and have very few split pits. 
Trees are hardy. Color is 90% red over yellow. 

PF-15A fruit ripen 13 days after Redhaven, are 
large, red over yellow, and freestone. Trees 
produce heavily and are hardy. 

PF-17A fruit ripen 17 days after Redhaven, are 
large, firm, and 70% red. Fruit are reported to 
be excellent for shipping. Trees are hardy. 

White-fleshed Peaches 

Raritan Rose fruit ripen 4 days after 
Redhaven, are firm, attractive, and freestone, 
with good quality. Trees are vigorous, hardy, 
and productive. 

White-fleshed Nectarines 

Arctic Glo fi"uit ripen 10 days before 
Redhaven, are medium-large, very firm, highly 
colored, and reported to ship well. Trees are 
vigorous and productive. 

Arctic Rose fi"uit ripen 7 days after Redhaven, 
are medium size, firm, very sweet, and highly 
colored. 

Arctic Queen fi'uit ripen 29 days after 
Redhaven, are large, firm, sweet, and highly 
colored. 

In 1997, I will conduct a more extensive 
evaluation of all the cultivars in this trial. I will 
evaluate fi"uit for size, color, taste, abnormali- 
ties (such as split pits), and texture. Tree vigor 
and productivity and disease resistance also 
will be evaluated. Also less favorable cultivars 
will be removed and possibly replaced with 
additional early cultivars. 

At this time, I recommend that Massachu- 
setts growers plant on a trial basis the following 
yellow-fleshed peach cultivars: Jerseydawn, 
Salem, Flavorcrest, New Haven, Madison, 
Harrow Beauty, Jim Dandee, and Harcrest. 
For a white-fleshed peach, Summer Pearl 
should be tried. Earliscarlet, Summer Beaut, 
and Fantasia are nectarines worthy of trial. 



•Xa •X* •X* *X» *JL* 
#Y% #T^ #Y* *i^ *V* 



18 



Fruit Notes, Volume 62 (Number 1), Winter, 1997 



Agri-Mek: A 1996 Field Trial in 
a Commercial Apple Orchard 



Glenn Morin and Roberta Spitko 

New England Fruit Consultants, Montague, Massachusetts 



The 1996 growing season witnessed the 
introduction of a new pest-management tool 
with the federal registration of Agri-Mek 
(Merck and Co.) for managing both leafminer 
and mite in apples and pear psylla in pears. 
Following the withdrawal of Omite from the 
marketplace in April, most apple producers 
were pleased to have another option for 
European red mite (ERM) control. However, 
Agri-Mek's late-spring registration combined 
with the absence of experimental work 
conducted in New England left most field 
consultants and growers with limited informa- 
tion on how this product would be utilized best 
in the rapidly approaching season. 

The active ingredient in Agri-Mek, 
abamectin, is a naturally derived substance 
produced by a soil microorganism and is 
effective at extremely low rates. Agri-Mek is 
not related to other currently registered 
materials and therefore should prove useful in 
managing tolerant pest populations and 
prolonging the effective life of presently 
available compounds when used 
in a rotational program. 
Abamectin is absorbed into the 
leaf tissue where it forms a 
reservoir of active ingredient 
against foliar feeding pests. As 
a result, Agri-Mek is currently 
recommended within six weeks 
after petal fall and in combina- 
tion with horticultural oil in 
order to maximize absorption. 
Affected individuals essentially 
are paralyzed, stop feeding, and 
die within a few days. 

Optimal timing is critical to 
the cost-effective use of this 
material. Ideally, one would 



expect a single application to provide season- 
long suppression of ERM and leafminer 
populations. The focus of our trial was 
European red mite, as this pest would likely be 
the primary target for most Northeast growers 
considering the use of this material. The two 
most vulnerable periods for ERM within the 
recommended application time frame are 1) 
petal fall, when the majority of overwintering 
egg hatch has been completed and 2) first- 
generation egg hatch approximately 3-4 weeks 
later. ERM populations are fairly synchronous 
at these two times and are more easily 
disrupted than when multiple life stages are 
present. The following study was conducted to 
determine which of these two application 
timings would prove more effective in 
managing ERM populations. 

Procedure 

Treatments were applied to adjacent, non- 
replicated plots in a commercial apple orchard 



Table 1. Materials, rates and application dates for 
Agri-Mek trial, 1996. Materials were delivered in 150 
gal /acre of water. All plots received 3 gal/acre oil on 
April 24. Check plot was treated July 7 with 18 oz/acre 
Carzol SP, July 25 with 5 lbs/acre Omite 30W, and 
August 9 with 3 pts /acre Vydate. 



Trt. Material + rate (product/acre) 



Timing 



1 
2 
3 

4 



Savey @ 3 oz 

Agri-mek @ lOoz + oil @ 1 gal 

Agri-mek @ 10 oz + oil @ 1 gal 

Check 



May 9 
May 23 
June 17 



Fruit Notes, Volume 62 (Number 1), FaU, 1997 



19 



owned and operated by Marshall Farms Inc., 
Fitchburg, MA. Each 1.5-acre plot consisted of 
three rows of primarily Mcintosh trees 
approximately 12 feet high, planted on 16 x 24 
foot spacing with a dilute tree row volume of 
280 gallons per acre. Treatments were made 
with a Hardie airblast sprayer calibrated to 
deliver 150 gal per acre while operating at 2.5 
miles per hour according to the treatment 
schedule outlined in Table 1. 

European red mite populations were 
evaluated by selecting randomly 15 leaves per 
tree from each of 4 trees per treatment. 
Composite samples then were brushed unto 
glass plates and populations estimated using 
standard leaf-brushing protocol. 

Results & Discussion 

There were no substantial differences 
between treatments with respect to European 
red mite control in this study. Both Agri-Mek 
timings as well as the prebloom Savey 
application, included for comparison, were 
successful in suppressing ERM populations 
below injurious levels through the last week of 
August. Estimated mite populations in these 



plots ranged from 2.0 - 7.2 per/leaf on August 
28 (Figure 1) with little or no foliar damage 
evident. ERM populations in the check plot, 
which received only a prebloom oil treatment, 
built rapidly after first-generation egg hatch 
and exceeded 15.0 mites per/leaf by early July. 
Moderate foliar damage was noted at this time 
and rescue treatments of miticide were applied 
July 7 and July 25 to prevent excessive 
damage. A third treatment was made on 
August 9 to suppress late-season build up. 

It is interesting to note that, although both 
treatments were successful in suppressing 
ERM populations below injurious levels, trees 
receiving the later Agri-Mek treatment applied 
on June 17 had more motile forms consistently 
throughout the growing season. Pre-treatment 
counts on June 14 revealed approximately 4.0 
mites per/leaf, and although our application 
was successful in reducing that population, 
there were still significant numbers of motile 
forms on July 3 when one would expect to see 
full expression of the treatment. In contrast, 
the petal-fall treatment applied May 23 
suppressed ERM numbers to barely detectable 
levels until early August and final counts on 
August 28 were less than 50% of the later 



16-, 
14 ■ 
















-•— Agri-Mek + oil 5/23 


1 12. 

s. 

«, 10- 

I 8- 

o 

0) 

f « 

3 
C 

s 

2 - 

1 
i 




—*— Agri-Mek + oil 6/17 




^ 




^ 


.< 




5-Jun 14-Jun 19-Jun 3-Jul 


7-Aug 28-Aug 


Figure 1. Effect of various miticide treatments 


on European red mite 


populations. 





20 



Fruit Notes, Volume 62 (Number 1), Winter, 1997 



treatment. 

It is unclear why this later treatment did 
not perform as well as the petal-fall treatment. 
The increased amount of foliage present in mid 
June may have adversely affected spray 
penetration and allowed for greater survival of 
mites in the inner tree canopy. Perhaps 
hardening off of the leaf tissue was a factor. 
This event may have decreased absorption of 
active ingredient to the extent that nymphs 
hatching several days post-application were 
not well controlled. 



Conclusion 

It appears from the data presented here 
that either a petal-fall application of Agri-Mek 
or an application timed to coincide with first- 
generation egg hatch can, under favorable 



conditions, provide satisfactory season long 
suppression of European red mite similar to 
that provided by a prebloom application of 
Savey. 

The treatment directed at first-generation 
egg hatch was less effective possibly due to 
decreased spray coverage or decreased absorp- 
tion of Agri-Mek into the leaf tissue. This 
difference was of little consequence in this trial, 
as summer weather conditions were relatively 
cool with ample rainfall and season-long 
suppression was ultimately achieved. How- 
ever, had weather conditions been more 
conducive to rapid mite build up, additional 
summer miticides may have been necessary to 
manage the residual population left by the later 
treatment. 

Based on these data, we suggest the petal- 
fall application as the more desirable of the two 
options presented here. 



•X* *1/* *X* *X* *X* 

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Fruit Notes, Volume 62 (Number 1), FaU, 1997 



21 




Fruit Notes 



University of Massachusetts 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

Amherst, MA 01003 



Nonprofit Organization 
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'ruit Notes 



I by the Department of Plant & Soil Sciences, 
wividss, t^xtension, U. S. Department of Agriculture, and Massachusetts Counties Cooperating. 

Eklitors: Wesley R. Autio and William J. Bramlage 




50 

CO 



CD 
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Voaime 62, N&nber 2 
SPR^G ISSUE, 1997 

Table of Contents 

Improved Pesticide-treated Wooden Spheres 
for Controlling Apple Maggot Flies 

Comparative Level of Establishment of Released 

Typhlodromus pyri Predatory Mites in First-level 

and Second-level IPM Apple Orchard Blocks 

New England-wide Demonstration of an Integrated 

Pest Management (IPM) System for Apples and Consumer 

Education in IPM as a Pollution-prevention Strategy 

An Update on the 1994 NC-140 Apple Rootstock Trial 

An Update on the 1994 NC-140 Peach Rootstock Trial 

The Hay, Grain, and Feed Man: 
G. O. Bunnell, Northfield, Massachusetts 



Fruit Notes 



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Fruit Notes, Volume 62 (Number 2), Spring, 1 997 1 



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Fruit Notes, volume 62 (Number 2), Spring, 1997 



Improved Pesticide-treated Wooden 
Splieres for Controlling Apple 
Maggot Files 

Xing Ping Hu, Andrew Kaknes, and Ronald Prokopy 
Department of Entomology, University of Massachusetts 



In recent years, we have been working 
toward development of pesticide-treated spheres 
as a substitute for sticky spheres in controUing 
apple maggot flies. In the Spring 1996 issue of 
Fruit Notes, we reported on progress made 
through 1995 on development of pesticide- 
treated wooden spheres. Here, we assessed 
residual effectiveness against apple maggot 
flies of the best-performing version of pesticide- 
treated wooden spheres developed through 
1995 versus a new tjrpe developed in 1996. We 
also evaluated the performance of each of these 
sphere types in controlling apple maggot flies in 
a small commercial orchard. 

Materials and Methods 

The 1995-version spheres consisted of three 
layers of materials: first layer = 76% sugar, 4% 
wheat flour, and 20% Glidden gloss red paint; 
second layer = 1% Digon 4E (=0.5% dimethoate), 
and 99% Glidden gloss red paint, third layer = 
shellac. The layer of shellac was intended to 
reduce the loss of fly feeding stimulant (sucrose) 
from the sphere surface during rainfall. To a 
significant degree, this loss was prevented. 
However, following rainfall or a series of heavy 
dews, spheres coated with shellac sometimes 
turned whitish in color, rendering them less 
visually attractive to apple maggot flies than 
completely red spheres. 

The 1996-version spheres featured a new 
approach to extending the residual activity of 
sucrose. Rather than rely on application of 
shellac (or several other applied substances 
that we evaluated prior to 1995) to extend the 
residual activity of sucrose, we instead drilled 



14 evenly spaced holes (1/4 inch diameter x V2 
inch deep) into each sphere and filled each hole 
with a mixture of 94% sucrose, 6% flour. This 
was followed by application of 2 layers of paint 
(same composition as first 2 layers of paint 
applied to 1995 - version spheres). 

To assess toxicity of spheres to apple 
maggot flies, in early July of 1995, twelve 1995- 
version spheres were hung fi-om branches of 
apple trees near Prokopy's small commercial 
orchard in Conway. Every other week 
thereafter until apple harvest, two spheres 
were brought to the laboratory for assays. In 
early July of 1996, the same procedure was 
followed for 1996-version spheres. For assays, 
thirty flies were allowed to stay and feed on 
each sphere for up to five minutes, follovdng 
which, flies were placed in cages and examined 
for mortality 24 hours later. Rainfall was 
measured by a rain gauge placed near trees. 

Comparison of pesticide-treated spheres 
with sticky spheres for providing direct control 
of apple maggot flies was made in the Prokopy 
orchard, which consisted of 50 trees (10 rows x 
5 trees per row, primarily Liberty/M.26). In 
1995, each tree in the five eastern rows received 
two 1995-version pesticide-treated spheres, 
whereas each tree in the five western rows 
received two sticky (Tangletrap-coated) spheres. 
In 1996, the arrangement was reversed, with 
each tree in the five eastern rows receiving two 
sticky spheres and each tree in the five western 
rows receiving two 1996-version pesticide- 
treated spheres. Spheres were deployed in July 
each year, were unbaited, and were positioned 
optimally for attracting apple maggot flies. At 
harvest, every tenth picked apple was 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



Table 1. Residual effectiveness of dimethoate-treated red spheres (before treatment) against 
laboratory-tested apple maggot flies. 


Spheres* 


Weeks of sphere 


exposure 


Retreated 
in orchard with 


2 


4 


6 


8 


10 12 sucrose 


1995 Version Fly mortality (%) 

Cumulative rainfall (in.) 

1996 Version Fly mortahty (%) 

Cumulative rainfall (in.) 


90 
0.4 

95 
1.6 


80 
2.0 

90 
2.0 


60 
4.3 

85 
2.4 


40 
5.1 

80 
3.2 


30 -- 70 
5.7 

70 55 75 
7.2 10.2 


*Spheres in 1995 received two coatings of paint and a third coating of shellac. Spheres in 1996 
were drilled with 14 holes subsequently filled with a sucrose/flour mixture and received two 
coatings of paint. 



examined carefully for 
maggot egglaying stings. 

Results 



presence of apple 



Results of laboratory assays of residual 
efifectiveness of pesticide-treated spheres against 
flies (Table 1) show that after four weeks of 
exposure and two inches of rainfall, 80% of flies 
placed on 1995-version spheres died compared 
with 90% that died when placed on 1996- 
version spheres. In 1995, after ten weeks of 
exposure (5.7 inches of rain), 1995-version 
spheres killed only 30% of tested flies. In 1996, 



after ten weeks of exposure (7.2 inches of rain), 
1996-version spheres killed 70% of tested flies. 
In fact, for every period when assayed, 1996- 
version spheres outperformed 1995-version 
spheres (Table 1). Retreating spheres with 16% 
sucrose solution (in water) after twelve weeks 
of exposure restored effectiveness of 1995 
spheres to a level of 70% fly kill, demonstrating 
that loss of sucrose as feeding stimulant and 
not loss of dimethoate as toxicant was the 
principal factor responsible for decreasing 
performance. 

Results of tests assessing the capability of 
pesticide-treated spheres for providing direct 



Table 2. Effectiveness of dimethoate-treated red spheres versus sticky-coated 
red spheres in providing control of apple maggot flies in a small commercial 
orchard. 


Year 


Treatment 


Number of 
fruit examined 


Fruit with fly 
egglaying stings (%) 


1995 
1996 


Spheres - 1995 version 
Sticky spheres 

Spheres - 1996 version 
Sticky spheres 


1263 
1294 

896 
913 


1.0 
0.9 

0.6 
0.7 


1 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



within-orchard control of flies (Table 2) show 
that 1995-version spheres as well as 1996- 
version spheres provided a level of control 
essentially identical to that provided by sticky 
spheres (1.0% fruit injury or less). In contrast, 
96 and 97% of fruit on unmanaged apple trees 
and about 250 yards away was injured by apple 
maggot flies in 1995 and 1996, respectively. In 
1995, pesticide-treated spheres were dipped in 
a 16% sucrose solution weekly after the fifth 
week of exposure to renew feeding stimulant. 
In 1996, no such dipping was performed. 

Conclusions 

Our findings show that 1996-version 
pesticide-treated spheres (each with 14 sugar- 
filled holes) maintained high season-long 
residual activity against apple maggot flies and 



provided excellent control of this pest under 
commercial orchard conditions. They have a 
distinct advantage over earlier versions of 
pesticide-treated spheres in requiring no re- 
treatment with sucrose solution during the 
growing season. Their major shortcoming is 
the need to drill holes in each sphere and then to 
fill each hole with sucrose/flour mixture 
annually before painting. In the coming year, 
we plan to determine the optimum number and 
size of holes needed to attain season-long 
sphere effectiveness and to determine if one 
rather than two coats of paint will suffice. 

Acknowledgments 

This work was supported by a grant from 
the USDA Northeast Regional IPM Competi- 
tive grant and Hatch funds. 



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Fruit Notes, Volume 62 (Number 2), Spring, 1997 



Comparative Level of Establishment 
of Released Typhlodromus pyri 
Predatory Mites in First-level and 
Second-level IPM Apple Orchard Blocks 

Ronald Prokopy, Starker Wright, and Jennifer Mason 
Department of Entomology, University of Massachusetts 

Jan Nyrop, Karen Wentworth, and Carol Herring 

Cornell University, NY Agricultural Experiment Station, Geneva 



As described in the Spring 1994 issue of 
Fruit Notes, Amblyseius fallacis is the most 
commonly occurring predatory mite in Massa- 
chusetts apple orchards. Unlike orchards in 
many other states, few Massachusetts apple 
orchards harbor detectable levels of 
Typhlodromus pyri predatory mites. Previous 
studies in Massachusetts have shown that A. 
fallacis rarely builds to levels capable of 
providing effective control of European red 
mites until mid-July at the eairliest, and often 
not until August. In contrast, studies in New 
York have shown that T. pyri, where 
established, can provide effective biocontrol of 
European red mites beginning as early as May. 

In 1995, we released T. pyri into two first- 
level IPM and two second-level IPM block of 
apple trees in each of six commercial apple 
orchards in Massachusetts. Here, we report on 
the abundance of T. pyri in samples taken in 
September of 1995 and 1996 in each of these 
blocks as well as in adjacent first- and second- 
level IPM blocks where no T. pyri were 
released. 

Materials & Methods 

All six orchards were located in west-central 
or east-central Massachusetts. Each block was 
comprised of about 60 trees of the cultivars 



Mcintosh, Empire, or Cortland (on M.7 or M.26 
rootstock). First-level IPM blocks received 
pesticide sprays applied by growers timed 
according to pest and weather-monitoring 
activities that the growers themselves carried 
out. Second-level IPM blocks were treated 
identically to first-level blocks through early 
June. Thereaft;er, no pesticide of any type was 
applied to second-level blocks. Instead, a 
combination of behavioral, cultural, and 
biological control techniques was used. 

In 1995, blossom clusters harboring T. pyri 
were picked fi-om an orchard at the New York 
State Agricultural Experiment Station at 
Geneva, transported in a cooler by automobile 
to Massachusetts on the same day when picked, 
and placed the following day in targeted blocks. 
This involved using twist-ties to attach 50 
blossom clusters to the central tree of each 
target block. 

In September of 1995 and 1996, 25 leaves 
were picked at random from the central tree 
(that is, the release tree) in each block receiving 
T. pyri and 25 leaves fi-om each of four trees 
nearest the central tree. A similar protocol was 
followed for sampling central and adjacent 
trees in first- and second-level blocks not 
receiving released T. pyri. Sample leaves were 
cooled and shipped to Geneva, New York for 
identification and counting of predatory mites. 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



Table 1. Abundance of mite predators on leaves sampled in September from first-level and 
second-level IPM blocks in which T. pyri were or were not released in May of 1995. 



Species 




Year 


Average number of predators per leaf* 




First-level IPM 


Second-level IPM 


Non-release 
block 


Release 
block 


Non-release 
block 


Release 
block 


T.pyri 

A. fallacis 




1995 
1996 

1995 
1996 


0.00 b 

0.02 b 

0.15 a 
0.28 a 


0.04 ab 
0.19 ab 

0.14 a 
0.11a 


0.00 b 
0.01b 

0.11a 
0.13 a 


0.07 a 
0.42 a 

0.19 a 
0.18 a 


*Values in 


each row 


followe 


d by the same letter are 


not significantly different at odds of 19 to 1. 



Results 

For T. pyri, the results (Table 1) show that 
for the 1995 samples, small but detectable 
numbers of this species were found in the 
release blocks, but none were found in the non- 
release blocks. For the 1996 samples, numbers 
cf T. pyri in the release blocks averaged 
considerably greater than they did in these 
same blocks in 1995, suggesting that a buildup 
of T. pyri had occurred. Almost no T. pyri were 
detected in 1996 samples taken in the non- 
release blocks. Interestingly, when data for 
1995 and 1996 release blocks were pooled, 
analysis indicated a significantly greater 
average number of T. pyri in second-level than 
in first-level IPM blocks. 

For A. fallacis, the results (Table 1) show 
quite similar numbers of predators of this 
species present in each t3rpe of block each year. 
When data for 1995 and 1996 were pooled, 
analysis indicated no significant difference in 
average number of A. fallacis between second- 
level and first-level IPM blocks. 

Examination of grower spray schedules 
revealed that no insecticides other than 
Guthion, Imidan, Lorsban, or Sevin (as a 
thinner) and no acaricides other than oil. 



Omite, Apollo or Savey were applied to any 
blocks during either year. None of these 
materials is known to be harmful to T. pyri. We 
believe that the significant negative effect of 
first-level compared with second-level IPM 
practices on the buildup of T. pyri was due to 
fungicide use from early June onward in the 
first-level blocks. Fungicides used after early 
June included Penncozeb, Dithane, Ziram, 
Polyram, Benlate, Topsin, and Captan. The 
first four of these materials are known to have 
detrimental effects on T. pyri. 

Conclusions 

Our findings indicate that by the end of the 
growing season of the year following their 
release, T. pyri mite predators appeared in 
readily detectable numbers in nearly all blocks 
in which they were released. The only 
exception occurred in one of the six orchards, 
where they were detected in neither of the 
release blocks. This orchard received 2 
applications of Dithane annually in May, which 
might have impacted establishment of T. pyri 
negatively. It appears from our results that 
pesticides, particularly certain fungicides, have 



Frait Notes, Volume 62 (Number 2), Spring, 1997 



a greater negative impact on buildup of T. pyri Acknowledgments 

than on buildup of A. fallacis. We suggest, 

therefore, that growers who are considering 

releasing T. pyri to attain establishment do so 

only in blocks that will not be treated with 

pesticides that may be harsh on T. pyri, 

including pyrethroid insecticides, acaricides 

such as Carzol, and fungicides such as Ziram or 

EBDC-based materials. 



This work was supported by a USDA 
Northeast Regional IPM Competitive Grant 
and by State/Federal IPM funds. 



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Fruit Notes, volume 62 (Number 2), Spring, 1997 



New England-wide Demonstration of 
an Integrated Pest Management (IPM) 
System for Apples and Consumer 
Education in IPM as a 
Pollution-prevention Strategy 

WilUam M. Coli and Craig S. HoUingworth 
University of Massachusetts 

James F. Dill 
University of Maine 

Alan T. Eaton 

University of New Hampshire 

Heather Faubert 
University of Rhode Island 

Lorraine M. Los 
University of Connecticut 



The strategies known collectively as IPM 
have been recognized as one way to reduce the 
amount of agricultural chemicals released into 
the environment. IPM has been shown to 
address the needs of New England agriculture, 
and pollution prevention, by reducing and 
optimizing pesticide use. 

Many New England growers have been in 
the forefront of widespread early adoption of 
these new technologies, partly as a conse- 
quence of aggressive, regional Cooperative 
Extension outreach programs. In Massachu- 
setts, for example, approximately 40% of the 
state's cranberry and apple acreage, and about 
20% and 9% of strawberry and sweet com 
acreage, respectively, receive some form of IPM 
monitoring and advice from private-sector 



scouts or consultants, and still larger acreages 
are managed under IPM by the growers 
themselves. Such widespread grower adoption 
of IPM has set the standard for environmen- 
tally responsible agriculture. 

However, although consumers typically 
express concern about perceived public-health 
and food-safety risks associated with 
agrichemical use, a very small percentage of 
the general public has even heard of IPM, and 
still fewer recognize its potential benefits and 
the extent of its use. More widespread 
demonstration and consumer education of the 
environmental benefits of IPM are likely to 
enhance positive consumer attitudes towards 
local agriculture. 

In spite of the potential benefits to 



Fnilt Notes, Volume 62 (Number 2), Spring, 1997 



agriculture of increased adoption and consumer 
awareness, successful IPM strategies demon- 
strated in one state have not always been 
adopted regionally. This is partly due to a 
tendency of growers to emphasize uncertainty 
associated with farm-to-farm or state-to-state 
differences in pest complexes, weather, normal 
cultural practices, intended markets, etc. Since 
IPM adoption has not been universal, there 
remains a need for regionally-consistent 
systems to evaluate progress toward the 
Federal-policy goal of IPM implementation on 
75% of managed acres by the year 2000. 

One possible way to measure extent of 
grower IPM adoption is by use of commodity- 
specific IPM definitions, known as IPM 
Guidelines, originally developed in Massachu- 
setts. These guidelines, in the form of 
checklists and a related point system, have 
been used since 1990 as the basis for successful 
implementation of the state Farm Services 
Agency (formerly ASCS) cost-sharing program 
in Integrated Crop Management (ICM) and a 
related state-endorsed consumer education and 
marketing effort known as Partners With 
Nature. 

With this background in mind, in 1994, a 
small group of New England Extension and 
research specialists successfully acquired a 
Region I USEPA Pollution Prevention Incen- 
tives to the States (PPIS) grant which sought to 
address some of the issues identified above. 

The principal goals of the project, for which 
the University of Massachusetts served as lead 
unit, were: to develop consistent, well-defined, 
and quantifiable apple IPM guidelines for each 
New England state; to test state IPM 
guidelines as a pollution prevention methodol- 
ogy at the state and regional level; and to 
educate the media and the general public about 
IPM and its benefits. 

Our specific objectives were: to involve 
University research and extension staff, 
growers, and private-sector IPM professionals 
in the design of apple IPM Guidelines for each 
of the New England states; to demonstrate the 
resultant state guidelines on one 5-to-lO-acre 
block in each state, and compare results to a 
similar sized check block managed with a 



calendar-based spray program without pest 
monitoring; to calculate and compare the 
Environmental Impact Quotient (Kovach et al., 
1992) for each block, as a measure of pollution 
prevention; and, to hold a field day in each state 
on the farm of the demonstrating grower to 
which the press and general public are invited. 

To the best of our knowledge, until this 
project, no successful attempt had been made 
within Region I to develop consistent IPM 
guidelines for several states in a region, to carry 
out an extensive and regionally-coordinated 
IPM demonstration for any crop, nor to use the 
results to educate the general public about 
environmentally-sound agricultural practices. 

An initial project planning meeting of 
several state collaborators was held in 
conjunction with the New England Fruit 
Meetings in January, 1995. Due to delays in 
getting the project organized, no growers 
participated in this meeting. Subsequently 
(Spring 1995), however, ME, CT, RI, and NH 
formed a Guideline Design Committee (GDC) 
consisting of 6-14 members, and each 
committee met at least once. The University of 
Massachusetts investigators participated in 
the ME and RI meetings. Each committee 
reviewed the University of Massachusetts 
guidelines template, and elected to modify it to 
fit the pest-management situation in that 
state. Modifications included: elimination and 
addition of some practices in the MA guidelines 
and changes to the point system used. 

In Massachusetts, an IPM Certification 
Study Committee was formed by the Massa- 
chusetts Fruit Growers' Association late in 
1994, and this group solicited input on 
guideline modifications from growers, private 
IPM consultants, and University staff indepen- 
dently of the EPA-funded project. Modified 
guidelines were compiled by the University of 
Massachusetts investigators. Development of 
all state-specific apple IPM guidelines was 
completed by June, 1995. 

Each state identified one or more demon- 
strating growers (DG) who implemented the 
farm-specific IPM system, and conducted other 
planned activities. Cooperating growers who 
agreed to demonstrate the IPM system were: 



10 



Frait Notes, volume 62 (Number 2), Spring, 1997 



Massachusetts, Joe Sincuk (Uni- 
versity of Massachusetts Horti- 
cultural Research Center, 
Belchertown); Connecticut, Ken 
Shores (Johnny Appleseed's 
Apple Orchard, Ellington); Rhode 
Island, Randy McKenzie (Phan- 
tom Farms, Cumberland); New 
Hampshire, Ben Ladd and 
Melanie Stephens (Great Brook 
Farm, Canterbury), Steve 
Gatcomb (Manager of Upland 
Farm, Peterborough); and Maine, 
Reed Markley (Lakeside Or- 
chards, Manchester). 

Original plans called for each 
cooperator to demonstrate the state IPM 
system, and compare results to a "convention- 
ally managed" block. However, given that all 
cooperators had been identified because of their 
knowledge and use of IPM, none were willing to 
"go backward" (i.e., apply pesticides on a 
preventative basis), even when funds to 
purchase extra chemical were offered. Al- 
though this development compromised the 
original project design somewhat, it provided 
testimony to the level of commitment to IPM 
common in the region. 

Hence, only the demonstration at the 
University of Massachusetts Horticultural 
Reserch Center (HRC) included both an IPM 
block, and a conventional (i.e., modified 
preventative spray program) block. The HRC, 
while a University research facility, is also a 
commercial orchard, with support for the farm 
dependent almost completely on fruit sales, just 
as with a private-sector orchard. The site has a 
long history of IPM adoption. 

Pesticide application results in HKC 
IPM and "conventional" blocks. IPM 
blocks received regular monitoring and spray 
recommendations by University-affiliated staff. 
The sole comparison block was designed to 
reflect the number of sprays that could be 
applied if a grower were inclined to use a 
preventative spray program. In actual fact, the 
"conventional" program was very conservative, 
using as it did only one spray for apple maggot 



Table 1. Number of spray events in traditional and IPM 
blocks, University of Massachusetts Horticultural 
Research Center, 1995. 



Conventional 



IPM 



Acaricides 
Fungicides 

Insecticides (incl. 2 oil) 
Herbicides 

TOTAL 



3 

10 
7 
1 

21 



4 
6 
5 
1 

16 



fly, not the 2 to 3 that might normally be 
applied. 

As shown in Table 1, weekly monitoring of 
the IPM block and use of appropriate action 
thresholds resulted in 24% fewer spray 
application events compared to the modified 
preventative spray program. While this 
represents a savings in labor and other costs 
associated with spray application (e.g., fuel, oil, 
wear and tear) and one can hypothesize a 
reduced potential impact on the environment, 
the number of spray events alone gives no 
information on potential environmental im- 
pacts of IPM use. 

One measure of potential environmental 
benefit from IPM, calculation of the Environ- 
mental Impact Quotient (Kovach, et al., 1992), 
which takes into account toxicity of individual 
pesticides, is reported on elsewhere for all 
participating demonstration sites. A second 
measure, the dosage equivalent (DE), which 
reflects the rate of pesticide used as a 
percentage of the recommended rate, was 
completed for the HRC (Table 2). From Table 2, 
it can be seen that the IPM block received 
nearly 32% fewer pesticide DE's than the 
traditionally managed block. We believe this 
difference represents a typical situation in a 
grower orchard, where full recommended rates, 
which are known to have a wide margin for 
error, are rarely used. The implication of using 
dosage equivalents rather than spray events is 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



11 



Table 2. Dosage equivalents of pesticide used in conventionally 


managed and IPM blocks, University of Massachusetts Horticultural 


Research Center 


1995. 










Conventional 


IPM 


Difference 


% Difference 


Acaricide 


3.2 


3.0 


0.2 DE 


7% 


Fungicide 


13.6 


7.9 


5.7 DE 


42% 


Herbicide 


1.4 


0.7 


0.7 DE 


52% 


Insecticide 


6.1 


3.6 


2.5 DE 


40% 


Oil 


1.3 


1.1 


0.2 DE 


15% 


Total 










Non-oU 


21.3 


14.5 


6.8 DE 


32% 


1 



most noticeable in the case of herbicide, where 
both blocks received a single application, but 
52% less actual pesticide was applied in the 
IPM block. 

In spite of the lower dosage equivalents of 
pesticide use, pest damage appeared to be no 
different among the two blocks. No harvest 
survey data are presented because the entire 
crop was heavily damaged (over 80% injury) 
from a hail storm in late May. As a consequence 
of this extensive damage, normal harvest 
surveys could not be conducted easily. 

Pesticide residue analysis, HRC. Al- 
though not originally proposed as a project 
activity, location of the Massachusetts Pesti- 
cide Analj^ical Lab (MPAL) at Amherst, 
presented an opportunity to conduct a 
comparison of pesticide residues in the IPM and 
traditional blocks at the HRC. Such 
comparative residue data largely are lacking, 
and should provide useful baseline information 
for gauging the true environmental and public- 
health impacts of IPM use. Fruit samples were 
collected from each block type and frozen for 
later analysis during fall and winter. The 
authors would like to offer special acknowledg- 
ment for the cooperation and assistance offered 
to us by John Clark, Lab Director, and his staff, 
Dan Tessier and Andy Curtis. 

Table 3 shows results of residue analysis 



performed for 9 of 11 pesticides applied. No 
data are presented for azinphosmethyl 
(Guthion"") due to applicator error, and no 
analysis was attempted for the acaracide 
fenbutatin oxide (Vendex'*"). It is important to 
note that no residues were detected at a limit of 
detection of 0.2 ppm for seven of the materials 
applied in either the IPM or Conventional 
block. This finding is consistent with residue 
test results in the literature, which t5Tjically 
show that a minimum of 50% of all produce 
samples tested contain no detectable residues. 
Unfortunately, it is often assumed that the 
percent of produce containing pesticide resi- 
dues is much higher than it actually is. This 
discrepancy offers further compelling evidence 
of the need to educate the media and the 
general public about the realities of agricul- 
ture. 

For the benzimidazole fungicide benomyl, 
residues were no different in IPM and 
conventional blocks, but both showed residues 
in the parts per billion (ppb) range, orders of 
magnitude below the allowable tolerance. 
Residues of propargite, registration of which 
was recently canceled voluntarily by the 
registrant, also were well below tolerances, and 
represented the sole example of significantly 
lower residues in response to an IPM strategy. 
In this case, although more propargite 



12 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



Table 3. Pesticide residues on apples at harvest in IPM and Traditional blocks, 
University of Massachusetts Horticultural Research Center, 1995. 







Total pesticide residues 


Chemical 


Brand name 


IPM 


Conventional 


Benomyl^ 


(Benlate"°) 


0.02 ppb 


0.02 ppb 


Captan 


(Captan*") 


ND" 


ND 


Carbaryl 


(Sevin'") 


ND 


ND 


Endosulfan 


(Thiodan'") 


ND 


ND 


Fenarimol 


(Rubigan™) 


ND 


ND 


Mancozeb 


(Penncozeb"") 


ND 


ND 


Permethrin 


(Ambush"") 


ND 


ND 


Phosmet 


amidan"") 


ND 


ND 


Propargite'" 


(Omite"") 


0.49 ppm 


* 0.75 ppm 



tolerance of benomyl = 7 ppm. 

''ND = nondetectable, limit of detection = 0.2 ppm. 

"Tolerance of propargite = 3 ppm. 

*StatisticaUy significant difference existed between IPM conventional at odds of 19 to 

1. 



applications were used in the IPM block based 
on monitoring results, a lower rate was applied, 
and resultant residues were lower statistically. 
Such a low-dose strategy may represent a way 
for the material to be used again in the future. 

Environmental Impact Quotient (EIQ). 
Although each of the measures described above 
(i.e. numbers of sprays applied, dosage 
equivalents applied, and harvest residues) 
gives some information on potential reduction 
in environmental and other pollution, the 
actual measurement of such reductions is 
another matter. In addition to the fact that 
there is no agreement on the best techniques for 
measuring environmental impacts of pesti- 
cides, environmental testing of any sort is very 
expensive and demands the utmost care in 
sample collection and analysis. 

Partly in response to the need for some 
measure of environmental impacts of agricul- 
tural chemicals, Kovach and his colleagues at 
Cornell University devised the Environmental 
Impact Quotient (EIQ). The EIQ assigns 
values to chemicals based on such parameters 



as mode of action (i.e., non-systemic, systemic); 
toxicity to humans, bees, rabbits, birds, 
beneficial arthropods, and fish; soil residue half 
life; plant surface residue half life; and leaching 
and runoff potential. Although the resultant 
EIQ nvmabers have no meaning per se, they are 
intended to provide growers and others with a 
means to determine relative differences among 
pesticides or pest-management strategies. 

It should be noted that a number of flaws in 
the EIQ have been pointed out by Dushoff et al. 
(1994) in the journal American Entomologist. 
In addition to problems with scaling, weighting 
of effects, and inert ingredients, those authors 
point out that "...even benign substances are 
given ... an EIQ of at least 6.7." By way of 
illustrating an extreme example, "...if water 
were considered a pesticide, it would have an 
EIQ of 9.3. This means that 20 lbs per acre of 
water would be considered worse than a 1 lb 
application of parathion..." Of course, water is 
not a pesticide. However, another example 
using actual orchard pesticides can be seen in a 
comparison of the EIQ Field Use Rating for 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



13 



dormant oil (EIQ value of 37.7) and a 25 WP 
formulation of permethrin (EIQ value of 56.4). 
The EIQ Field Use Rating is determined by 
multiplying the EIQ Value (from a table) times 
the percent active ingredient (% A.I.) Of the 
material times the rate of pesticide application 
per acre, or: 

EIQ Field Use Rating = 

EIQ Value * % A.I. * Rate per Acre 

For Permethrin, used at 5 oz. per 100 gal. 
and applying 300 gal. per acre (or 0.9 lbs. per 
acre), this results in an EIQ Field Use Rating of 
13 (56.4 X .25 X 0.9 lbs). This is obviously much 
lower than the field use rating of 226 for oil used 
at a rate of 2 gal. per 100 gal. and applying 300 
gal. per acre (37.7 x 1 x 6 gal), because oil is 
100% active ingredient, and is used at a much 
higher per-acre rate. In spite of the flavors in the 
EIQ, no other more appropriate model is in 
widespread use, to the best of our knowledge, 
although several were reviewed in 1994 by Lois 
Levitan and colleagues at Cornell in a report to 
the Northeast Sustainable Agriculture Re- 
search and Extension (SARE) program. Hence, 
with all the provisions noted above, the EIQ for 
each of the blocks in our demonstration is 
presented in Table 4. 

If nothing else, the EIQ numbers point out 
that IPM is not a "one size fits all" strategy, and 



that differences in pest pressure, environmen- 
tal conditions, and grower management style 
often govern both the choice of pesticides and 
their application frequency. For example, 
while fungicides contributed the largest portion 
of the EIQ number in five out of six IPM blocks, 
one site in New Hampshire, which used a new 
insecticide (imadacloprid) which is very safe to 
predator mites but highly toxic to bees, had a 
much higher insecticide/acaricide EIQ than 
any of the other blocks. This probably does not 
actually represent greater environmental 
damage, however, because imidacloprid is 
applied after petals have fallen, and bees are no 
longer foraging in fruit trees. Nonetheless, use 
of the material results in a substantially higher 
EIQ rating. 

Total EIQ numbers ranged from as low at 
50% of the comparison traditional block to as 
high as 87% of that block, once again pointing 
out the normal differences among blocks for 
reasons described above. Ideally, had it been 
possible to set up a comparison block in each 
state which would have been subjected to the 
same weather and pest pressure, such 
comparisons would have had a much stronger 
biological basis, and their validity would have 
been strengthened. 

Field days. Field days were held 
successfully in four participating states in 
1995. Maine held their event on May 24, 1996 



Table 4. EIQ calculations for IPM demonstration blocks in five New England states, compared to 
a traditionally-managed block at the University of Massachusetts Horticultural Research Center, 
1995. 


Pesticide type 


Conventional 


IPM block by state 






block 
MA MA RI 


CT 


NHl 


NH2 


ME 


Insecticides/ 
acaricides 
Fungicides 
Herbicides 
EIQ Totals 


586 438 765 

1341 617 865 

52 57 ** 

1979 1112 1630 


222 

777 
** 

999 


1007 

334 

** 

1341 


439 

1288 

** 

1727 


306 

1047 

** 

1353 


**Not calculated 













14 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



to coincide with bloom, a time when orchards 
are very attractive. In facihtating planning for 
these events University of Massachusetts 
distributed information to collaborators on how 
to stage and run a field day, and how to write a 
press release. In addition, we provided 
examples of press releases and other related 
materials. Press releases sent, informational 
handouts about each farm, and educational 
materials handed out at the events included: a 
3-page fact sheet on disease-resistant apples, a 
fact sheet on IPM in Connecticut Apple 
Orchards, an "IPM Impacts" fact sheet, a 8- 
page handout on the Maine IPM Program, fact 
sheets defining relevant terms, a seven-page 
handout on insect and mite pests of apples, an 
apple pest chronology calendar and a descrip- 
tion of selected biological control agents (both 
taken fi-om the New England Apple Pest 
Management Guide), and a summary of 
comparative results (at the Massachusetts site 
only). 

Each field day consisted of a "walking tour" 
of the demonstration block with stops at 
various points of interest. For example, 
Connecticut collaborators (L. Los, G. Nixon, J. 
Clark and S. Olsen) staged a self-led walking 
tour which directed attendees through the 
orchard to view 12 different IPM "stations". 
Each station had a poster (approximately 2x2 
feet) which explained an important apple pest 
and included pictures of life stages, damage, 
etc. Next to each poster, insect traps with 
appropriate insects affixed, or weather moni- 
toring equipment for monitoring apple scab 
infection periods were displayed. In addition to 
displays within the orchard, the Connecticut 
IPM group provided two large display boards in 
a movable stand used for the orchard's pick 
your own operation. One board displayed the 
impacts of all IPM projects in the state, and the 
other dealt with beneficial insects. A total of 
about 700 people either came by the booth or 
took the walking tour. The large turnout was 
partly due to having a "built-in" audience 
available at a large pick-your-own orchard on a 
good fall day. Results were such that 
Connecticut plans to hold a similar event (self- 
funded) next fall as well. 



The Rhode Island field day also consisted of 
stops at sites in the IPM blocks, as well as 
samples and displays (i.e., display board of 
"Pest Control Then and Now", photos of insect 
and disease pests, fi-uit and leaf damage, 
beneficial insects, samples of scab-resistant 
cultivars, and several insect monitoring traps). 
An estimated 1,000 people participated in the 
field day, and the event received publicity on 
local TV channels. In addition, a front-page 
article about the project also ran in the 
Woonsocket Call. 

Although attendance at the Massachusetts 
field day was less spectacular, the University of 
Massachusetts Daily Collegian (circulation of 
17,000 throughout the 5-college area) sent a 
reporter who later wrote an article. New 
Hampshire had the greatest success in 
publicizing IPM by virtue of one front page 
article in the, July 16 Concord Monitor 
(circulation 23,500), a second fi-ont page article 
in the September 24 Sunday Union Leader, one 
Associated Press article sent out on the wire 
and at minimum picked up by the July 17, 1995 
Union Leader (cir. 89,000), and reported on by 
WTSN, Dover, NH (listenership 63,000), a live 
interview on WNHQ, Milford, NH on July 17 
(listenership 45,000), and a second AP article 
picked up by the September 25 Union Leader. 
In addition to the two IPM demonstration sites 
identified earlier, two other sites (the Hardy 
famiiys Brookdale Fruit Farm in Hollis, and 
Chuck and Diane Souther's Apple Hill Farm in 
Concord) also participated in the media tours. 

Cooperators in Maine arranged for the 
Governor to proclaim May 24 as "Maine IPM 
Technology Day", and the Commissioner of 
Agriculture delivered the Governor's proclama- 
tion at the event. The field day was announced 
to the apple grower community at the Trade 
Show in January, at the preseason IPM 
meeting in March, in the Pesticide Control 
Board Communicator newsletter, in the Apple 
Pest Report newsletter, at meetings of the 
Maine State Pomological Society Executive 
Council, and was advertised in several 
newspapers. The event was attended by about 
75 persons and featured displays from the 
Maine State Pomological Society; the USDA/ 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



15 



Downeast Resource Conservation & Develop- 
ment Cranberry IPM Program; the University 
of Maine Strawberry, Potato, Sweet Corn, 
Greenhouse, Blueberry, and Apple IPM 
Programs; the Maine Department of Agricul- 
ture; and the Maine Pesticide Control Board. 
In addition to the hosts, five other apple 
farmers agreed to serve as spokespersons and 
to answer questions. Arrangements were made 
to have a live InternetAVorld Wide Web 
connection, projector, and screen at the event, 
to demonstrate a developing technology with 
potential applicability for IPM users. 

Conclusions 

By virtue of the successful development of 
state-specific IPM guidelines in 5 of 6 New 
England states, by demonstrating (once again) 



that IPM can result in lower pesticide 
applications, lower dosage equivalents, and a 
lower EIQ rating, and by generating substan- 
tial media and consumer exposure for IPM 
throughout the region, the investigators 
believe that all project goals were achieved. 

Acknowledgments 

We sincerely wish to thank all the growers, 
consultants, university staff, and other apple 
industry members who participated in the 
guidelines design activity and the field 
demonstrations. Special thanks to those 
growers who allowed us to demonstrate the 
IPM systems and hold field days on their farm. 
Extra special thanks to Ken Shores who 
donated enough cider for 700 attenders of the 
Connecticut field day. 



«1« «1« «£« «% %1U 

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16 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



An Update on the 1994 NC-140 
Apple Rootstock Trial 

Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 



The NC-140 Technical Committee is 
comprised of about 75 university and govern- 
ment pomologists from the United States, 
Canada, and Mexico. During the more than 20 
years of this group's existence, several trials 



have been established, managed, and reported 
in a cooperative manner. In 1994, a trial was 
established at 25 locations throughout the 
United States and Canada, and it is managed 
by Rich Marini from Virginia Tech. Each 



Table 1. Trunk cross-sectional area, yield, yield efficiency, and fruit weight 


in 1996 


of Gala on several rootstocks in the 


1994 NC-140 Apple Rootstock Trial in | 


Massachusetts.' 
















Trunk cross- 


Yield 


Yield 


Fruit 


weight 




sectional area 


per 


tree 


efficiency 


(average 


Rootstock 


(in^) 


(lbs) 


(lbs/in' TCA) 


box count) 


M.9 EMLA 


2.1 def 


4.8 


cdef 


2.6 bedef 


98 


bed 


M.26 EMLA 


2.8 be 


2.2 


efg 


0.9 fg 


114 


de 


M.27EMTA 


0.7 i 


1.3 


fg 


1.7 defg 


107 


bcde 


M.9 RN29 


2.5 cd 


5.7 


bcde 


2.1 cdefg 


96 


bed 


M.9 Pajam 1 


2.4 de 


6.4 


bed 


2.8 bcdef 


114 


de 


M.9 Pajam 2 


3.0 ab 


9.0 


b 


3.1 bcde 


88 


b 


B.9 


1.9 ef 


4.2 


defg 


2.6 bcdef 


105 


bed 


B.491 


0.9 hi 


2.6 


defg 


2.7 bcdef 


129 


e 


0.3 


2.0 def 


5.7 


bcde 


2.8 bcdef 


112 


de 


V.l 


3.3 a 


8.1 


be 


2.6 bedef 


100 


bed 


P. 2 


2.1 def 


0.4 


g 


0.1 g 


— 




P. 16 


1.2 gh 


2.0 


efg 


1.7 defg 


112 


ede 


Mark 


2.3 de 


9.2 


b 


4.3 be 


105 


bcde 


P.22 


0.8 hi 


3.5 


defg 


4.5 b 


109 


ede 


B.469 


1.2 gh 


4.8 


cdef 


3.8 bed 


110 


cde 


M.9 Fleuren 56 


1.6 fg 


2.9 


defg 


2.0 defg 


104 


bed 


M.9 NAKBT337 


1.9 ef 


3.7 


defg 


2.1 cdefg 


97 


bed 


DeliciousM.26 EMLA" 


1.8 ef 


1.3 


fg 


0.9 efg 


61 


a 


Liberty/M.9 NAKBT337 


1.9 ef 


13.0 


a 


7.2 a 


96 


bed 


Fuji/Mark" 


2.2 de 


8.6 


be 


3.7 bed 


95 


be 


' Means within columns 


not followed by the same letter are significantly different 


at odds of 19 to 1. 














' Delicious, Liberty, and Fuji are pollenizers 


within each replication 







Fruit Notes, Volume 62 (Number 2), Spring, 1997 



17 



M.9 Fleuren 56 

M.9 NAKBT337 

M.9 EMLA 

M.9 Pajam 1 

M.9 RN29 1 .::m 

M.9 Pajam 2 














Trunk cross-sectional area (in^) 



Figure 1. Trunk cross-sectional area in 1996 of Gala on six clones of M.9 in the 1994 NC-140 
Apple Rootstock Trial in Massachusetts. 



M.9 Fleuren 56 

M.9 NAKBT337 

M.9 EMLA 

M.9 RN29 

M.9 Pajam 1 

M.9 Pajam 2 







0.0 2.0 4.0 6.0 8.0 

Yield per tree (lbs) 



10.0 



Figure 2. Yield per tree in 1996 of Gala on six clones of M.9 in the 1994 NC-140 Apple 
Rootstock Trial in Massachusetts. 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



■ : :- 




,4^ 


n 


m 


i^ ■:" '^ 
















illi^i:r 


'" ^;: ;; 




^'^■' 









taiiftaMi;:.jan>.watu-.->H^,.. >^j.t. ,*■,.... - ^1 a.^>v^^.>. 



ISli^^^^****'^ 



M.9 Pajam 1 

M.9 Fleuren 56 

M.9 EMLA 

M.9 NAKBT337 

M.9 RN29 

M.9 Pajam 2 ^^^ 

60 70 80 90 100 110 120 
Fruit size (average box count) 

Figure 3. Fruit size in 1996 of Gala on six clones of M.9 in the 1994 NC-140 Apple Rootstock 
Trial in Massachusetts. 




plating includes Gala on 17 dwarf rootstocks, 
replicated 10 times. The Massachusetts 
planting is located in Belchertown at the 
University of Massachusetts Horticultural 
Research Center. This article will give a brief 
update on tree performance through the third 
growing season. 

After three growing seasons, the largest 
Gala trees were on V.l, M.9 Pajam 2, and M.26 
EMLA (Table 1). The smallest trees were on 
P.22, B.491, and M.27 EMLA. The range in 
trunk cross-sectional area from smallest to 
largest was more than four fold. Yield per tree 
in 1996 (Table 1) was greatest for trees on V.l, 
M.9 Pajam 2, and Mark (ignoring the 
pollenizers) and least for trees on M.26 EMLA, 
P. 16, M.27 EMLA, and P.2. Relating yield to 
tree size, jdeld efficiency (Table 1) was greatest 
for trees on Mark and P.22 (ignoring the 
pollenizers) and smallest for trees on M.26 
EMLA and P.2. Fruit size (Table 1) was 
greatest for trees on M.9 Pajam 2 and least for 
trees on M.26 EMLA, M.9 Pajam 1, 0.3, and 



B.491. 

Among these 17 rootstocks, it is 
particularly interesting to look at the differ- 
ences among the six M.9 clones in the study. 
The range was more than expected. Trees on 
M.9 Pajam 2 were the largest of the M.9-rooted 
trees, nearly double the trunk cross-sectional 
area of trees on M.9 Fleuren 56 (Figure 1). M.9 
EMLA resulted in a tree intermediate in the 
range. Yield followed a similar pattern, with 
trees on M.9 Pajam 2 producing nearly three 
times the fi-uit of trees on M.9 Fleuren 56 
(Figure 2). Trees on M.9 Pajam 2 produced the 
largest fruit, averaging between 80 count and 
96 count (Figure 3). Fruit from trees on M.9 
Pajam 1, on the other hand averaged only a bit 
larger that 120 count. 

Clearly these data are only preliminary. 
A few more years will be required to begin solid 
evaluation of these rootstocks, but it is 
interesting to observe significant differences in 
these young trees. 



%1a %i« •Im «1« «£• 

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Fruit Notes, Volume 62 (Number 2), Spring, 1997 



19 



An Update on the 1994 NC-140 
Peach Rootstock Trial 

Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 



According the 1991A^eu; England Fruit Tree 
Inventory, conducted by the New England 
Agricultural Statistics Service, peaches com- 
prise only 7% (380 acres) of the tree-fruit 
acreage in Massachusetts; however, most of 
these fruit are sold directly to the consumer and 
are profitable. Further, acreage is expected to 
increase at a rate of 2-3% per year for the near 
future. Therefore, peaches are an important 
part of the Massachusetts tree-fruit industry. 

Peaches have a number of horticultural 
problems: they are subject to early decline; 
they can bloom too early and therefore be 
frosted, they often express too much vegetative 



vigor, and the flower buds or whole tree can be 
killed by winter cold. Rootstock can impact any 
or all of these problems. 

To begin to study the potential for using 
rootstock to overcome some limitations of peach 
growing, Massachusetts participated in an NC- 
140 trial studying the effects of 12 rootstocks 
and one interstem combination on the 
performance of Redhaven peach. The 
Massachusetts planting was established in 
1994 at the University of Massachusetts 
Horticultural Research Center in Belchertown 
and included eight replications. Rootstocks 
included were as follows with descriptions 



Table 1. Tnink cross-sectional area 


yield per tree, 


yield efficiency, and fi-uit size in 


1996 of Redhaven peach trees planted 


in 1994 as 


part of the 1994 NC-140 Peach 


Rootstock Trial in 


Massachusetts.^ 












Trunk cross- 




Yield 


Yield 


Fruit 




sectional area 




per tree 


efficiency 


weight 


Rootstock 


(in^) 




(lbs) 


(lbs/in' TCA) 


(oz) 


Lovell 


6.4 a 




19.4 be 


3.1 a 


6.9 a 


Bailey 


4.7 be 




27.9 ab 


6.2 a 


7.6 a 


TN 281-1 


4.4 be 




17.6 be 


4.0 a 


7.2 a 


Stark's Redleaf 


4.5 be 




27.9 ab 


6.0 a 


7.8 a 


GF305 


4.7 be 




27.5 ab 


6.0 a 


7.1 a 


Higama 


5.6 ab 




33.0 a 


6.0 a 


6.8 a 


Montclar 


5.3 ab 




20.2 be 


4.0 a 


6.4 a 


Rubira 


3.4 cd 




18.7 be 


5.7 a 


6.8 a 


Ishtara 


2.4 d 




11.9 c 


4.8 a 


6.7 a 


H7338019 


3.2 cd 




16.3 be 


5.1 a 


6.4 a 


BY520-8 


3.9 c 




18.3 be 


4.8 a 


6.9 a 


Guardian 


6.3 a 




25.1 ab 


4.0 a 


5.9 a 


Ta Tao 5/Lovell 


4.2 be 




18.3 be 


4.4 a 


6.8 a 


' Means within col 


umns not followed by the same 


letter are significantly 


different 


at odds of 19 to 1 













20 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



Ishtara 

H7338019 ETT 

Rubira 

BY520-8 ^^^^^ 

Ta Tao 5/Lovell 

TN 281-1 

Stark's Redleaf 

GF305 

Bailey 




Montclar gSgBW 

Higama 

Guardian 

Lovell 



t:X?!^i^iS^:Sg^^^»ss^Stismf'i^y 



mm^^m^'im^fi^i^A'^i^im^^^^^^'^^t^ 



^^^^^3 



0.0 



2.0 4.0 6.0 

Trunk cross-sectional area (in^) 



8.0 



Figure 1. Trunk cross-sectional area of Redhaven peach trees planted in 1994 as part of the 1994 
NC-140 Peach Rootstock Trial in Massachusetts. 



Ishtara 

H7338019 

TN 281-1 

BY520-8 

Ta Tao 5/Lovell 

Rubira 

Lovell 

Montclar 

Guardian 

GF305 

Stark's Readleaf 

Bailey 

Higama 




10 



15 



20 



25 



30 



35 



Yield per tree (lbs) 



Figure 2. Yield of Redhaven peach trees planted in 1994 as part of the 1994 NC-140 Peach 
Rootstock Trial in Massachusetts. 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



21 



provided by Greg Reighard (Clemson Univer- 
sity), the coordinator of the NC-140 trial: 



Lovell 

Bailey 

TN 281-1 
Stark Redleaf 

GF 305 

Higama 

Montclar 

Rubira 

Ishtara 

H7338019 
BY520-8 



Chance seedling of peach from 
California named in 1882, 
propagated by seed; 
Selection of peach from Iowa 
named in 1890, propagated by 
seed; 

Selection in Tennessee of "wild" 
peach, propagated by seed; 
Selection by Stark Bro's from a 
Tennessee Natural-tj^je root- 
stock, propagated by seed; 
Selection in 1940 in France 
from Montreuil peach, propa- 
gated by seed; 

Selection in France of peach 
from Japan, propagated by 
seed; 

Selection in France of peach, 
propagated by seed; 
Selection in France of peach, 
propagated by seed; 
Selection in France of a plum- 
peach hybrid, propagated by 
cutting; 

Selection in Ontario of peach, 
propagated by seed; 
Selection in Georgia of peach, 
propagated by seed; 



Guardian Selection in Georgia of peach, 

propagated by seed; 

Ta Tao 5 Selection in China of peach, 

propagated by grafting, used in 
the study as an interstem with 
Lovell as the rootstock. 

After three growing seasons, significant 
differences existed in trunk cross-sectional area 
(Table 1, Figure 1). Of the trees with pure 
peach rootstocks, H7338019 resulted in a tree 
only half the size of those on Lovell, the largest. 
Rubira also produced a small tree, and 
Montclar, Higama, and Guardian also pro- 
duced large trees. Ishtara, the plum-peach 
hybrid, resulted in the smallest trees, ones that 
on average were only 38% of the size of trees on 
Lovell. Yield varied similarly (Table 1, Figure 
2), with trees on Higama, Bailey, Stark's 
Redleaf, GF 305, and Guardian producing the 
most, and trees on Ishtara producing the least. 
Because, in general, the largest trees produced 
the most fi-uit, yield efficiency (the expression of 
5deld per unit tree size) did not vary 
significantly among rootstocks (Table 1). 
Likewise finiit size did not vary significantly 
among rootstocks (Table 1). 

Although several more years will be 
required to evaluate these rootstock ad- 
equately, it is interesting to observe the 
significant differences that have developed in 
this first fruiting season. 



♦ mi^ ml^ •i^ •Ia 
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22 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



EDITORS' NOTE: The following piece was sent to us by W. Lockeretz (Tufts 
University). It is from the Life Histories Collection from the Federal Writers' 
Project of the Works Progress Administration. It is a transcript of an interview of 
Mr. G. O. Bunnell during 1938 and 1939. At the time of the interview, Mr. Bunnell 
was 75-80 years old. 

The Hay, Grain, and Feed Man: 

G. O. Dunnell, Northfield, Massachusetts 



I'm getting this axe ready to fix the fences 
on Christian Hill that the hurricane busted. 
Not that the hurricane blew 'em down but it did 
blow down some trees. And the trees is what 
busted the fences. I dim' over one. Had to, to 
get to camp, and I see they was more down. 
Couldn't do anything that night because it was 
getting da'k, and I had to come home, but I'm 
going back just as soon as the roads get settled 
enough so's I can. 

It's a funny thing, but I don't think that, as 
a rule, there was as much wind over that way as 
we got here. What did most of the damage was 
the water. And, another funny thing I noticed 
was that of the trees that come down in the 
apple orchards, it was the ones that had never 
been grafted. Those that had been grafted 
stood up. 

How'd I know? I know most every apple tree 
they is on Colrain and Shelbume mountains, 
and in the north part of the town of Greenfield. 
'Cause I was the feller that grafted 'em, that's 
why! I used to go all over grafting trees. And I 
had ten or twelve hundred trees of my own, too, 
that I'd no business leaving. But people would 
come tease me and tell me how much extry they 
were willing to pay for my trouble, that I was 
generally on the move. Once I went to 
Greenfield. And I didn't get home for a week. 
Spent the nights there with the different ones. 

'Course, theys a trick to it. But 'most 
anybody can put on a scion so's it'll grow. But 
that ain't all they is to it. You got to figure what 
the tree's going to be shaped like. You shouldn't 
get the scions growing into each other the way 
most people do. And you ought to fix; the tree 



so's somebody can pick the apples without tying 
a couple of ladders together or hiring a balloon. 

Apple trees like to grow among the rocks - 
that is, most kinds do. The hills each side of our 
valley here are just right. All we can grow here 
that's any good is the Blue Pearmain. And they 
got such a tough skin that people don't like 'em. 
They are an awful good flavor, though, until 
they got mealy - oh, they^s others; russets and 
early transparent and so on. But what I was 
getting at is the way I found the best of raising 
good flavored apples. Apples grow wild over in 
Colrain. It is just as natural to find a wild apple 
tree in Colrain as it is to find a birch in 
Warwick. I had a lot of 'em in my woods. 
'Course, the fruit of a wild apple tree is no good 
except for cider. But the trees themselves is 
generally healthy. I'd find a good one, then I'd 
saw off such limbs as I thought should be off, 
and put a scion in it. If it was a fairly big limb 
that I figured would pinch the scion off if I didn't 
do something about it, I'd whittle a little thin 
wedge and put that in just beyond the scion, for 
the limb to pinch on to. What do I mean by 
scion? What that's a little shoot fi-om the brand 
of tree I wanted. I had Baldwin scions and 
Mcintosh scions and Porter scions, and all 
kinds of scions. I cut 'em in March - that's the 
best time to graft around here. Maybe, I'd 
make a Baldwin tree out of a wild apple tree, or 
a Greening, or a Northern Spy. Sometimes I 
fixed 'em so's they had different kind of apples 
on every limb. But that's nothing but a kind of 
joke. Nobody that runs an orchard wants trees 
with fruit all mixed up on 'em. 

I said I only put one scion to a limb. I always 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



23 



put two, 'cause somethin' might happen to one. 
They break off in ice storms sometimes. And I 
always put 'em one above the other 'cause I 
figured it's better and stronger that way. You 
whittle off one side the scion and stick it in the 
crack you've made with your knife in such a 
way that the live bark on the scion presses up 
against the live bark on the tree. And then you 
hold the scion in place with wax. Then you cut 
off all the limbs below the one that you've 
grafted. The sap has to go somewheres. And 
when it finds that the limbs have been cut off, 
and they ain't no place to go, except into the 
bark of the scions, that's where it goes. You've 
got to figger not to cut too many limbs off, 
though. For if thej^s more sap than can get into 
the scion and make it grow, it'll leak out under 
the w£ix and rot the scion off. I generally left the 
top of the tree pretty much alone until I found 
out how the scions were doing. If they were 
growing all right, I'd cut the top off then. 

Lot of people put on two scions the way I 
done. But when them both growed they let 'em 
grow together. That makes a crotch. And a 
crotch ain't strong. I always cut off one scion 
just before they growed together. And the bark 
would grow over the place and make a smooth 
branch. 

Once, I grafted a whole tree. And that tree 
stood up through the hurricane, too. Yer see, 
when a crust comes on the snow, or anjrthing 
happens so the mice can't hunt, you're supposed 
to go around the orchard tromping down the 
snow around the trees. You tromp it down hard 
right around the trunk, and the mice won't get 
to the bark. But I missed this tree someways. 
Or the mouse, maybe, was a wood rat. Anyway, 
it ett the bark all the way 'round. It was a good 
tree. Had good roots, and as it would die if I 
didn't do something about it, I thought I better 
try. I cut the trunk of the tree off and put scions 
all the way 'round in the bark. Enough of 'em 
grew so I managed to raise a tree. I told the 
feller who owns the place about it, and he found 
it hard to believe for it don't look no different 
than any other tree to him. 

Lots of people insist on growing an orchard 
from nursery stock, that's all right if you want 
to wait ten or fifteen years for a crop. But if you 



want your trees to begin bearing in three-four 
years you want to graft a few scions on to a full 
grown tree. If you take your scions from a tree 
that has apples you like, you can be sure that 
you'll get the same flavor apple when the scions 
begin to bear. But when you buy from a nursery 
you got to wait ten or twelve years to find out if 
you got what you paid for. 'Course, the/s some 
crook nursery men, I s'pose, but they ain't 
many. It's the agent who's the crook. And it's a 
pretty good game when a feller don't know he's 
been gypped until ten-twelve years. By that 
time the agent ain't no longer in the employ of 
the company, probably. And if he was, nobody 
would know who made the mistake and the 
whole thing be outlawed so's you couldn't get it 
into court. I don't say that a good nursery 
wouldn't be awful sorry it happened and make 
good, too. But the way they'd make good would 
be to give you some guaranteed new trees that 
you could wait for to bear for another ten- 
twelve years. 

When Doc Brown and his brother first come 
they lived in houses side by side. And they 
planted the two back lots for an orchard. I told 
the Doc that this wasn't a good place to raise 
apples, but the Doc said, "No, no," I was wrong. 
That he'd had the soil analyzed down at the 
State College. And that they said it was good 
soil and all right. "All right, Mister" I says. 
"Now you take out your little book and you 
write down what I'm going to tell yer. So's you 
won't forget it, I says. But you see more money 
when you took out your pocketbook to pay for 
them trees than you'll ever see coming back into 
it from your orchard." But, oh no, I was wrong. 

"What kind of trees be they," I wanted to 
know. "Baldwins," he says. And it seemed he 
had paid an extry price to get some real good 
trees. 

I see they wan't no use talking to him and 
trjdng to help him so I forgot about it 'til several 
years had gone by when I saw him and his 
brother working in the orchard. You know, 
they's a pest of borers that bores holes in the 
trunks of apple trees right above the ground, 
and if you're quick enough you can ram a wire 
in and either kill the borer, or fish him out, but 
if he's bored 'round a bend or two, you are out of 



24 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



luck - your tree is gone. So it pays to watch your 
orchard. Was a time when yer didn't need to 
spray your trees. But you do now - two-three 
times. 

Well, I goes down into the orchard and asks 
what they was doing. They told me. And I 
asked what kind of trees these was. 'Baldwins," 
they told me. A few of 'em are, I admitted. But 
most of 'em is Gravensteins. "Oh, no!" Says the 
Doc, "that can't be! It was a reliable firm we 
bought them of and they was guaranteed 
Baldwins - a 'specially good brand.' "Well," I 
says, "You still get your little book? Now, put it 
down, so you won't forget it, or tie a string 
around the trees, or somethin', and you just 
wait 'til theys apples on 'em and see.' 

But they didn't wait. The brother sold out to 
a poor, little runt of a mean, miserable, cuss 
that I don't want nothin' to do with. But I didn't 
know what a kind of low-lived skunk he was 
then, so I tried to be neighborly. I asked him 
what kind of trees he had in his orchard. He 
says that they was Baldwins. That that was 
what the ministers said that sold him the place. 
"Well, they ain't," I says. "They is Gravensteins 
- most of 'em." But they ain't no good!" he says. 



I told him I didn't think they was any good 
myself- not even for cider. He wanted to know 
how how I was so siire. And I showed him the 
difference in the leaves. He thought he had 
better wait and make sure before he did 
anything about it. That it didn't seem to him 
that ministers would lie. I told him he needn't 
wait to find that out. That everybody in 
Northfield knowed that ministers are the 
biggest liars they is, 'cause they honestly 
believe their lies themselves. That if he aimed 
to become a bonnie fidie resident of Northfield, 
he'd better find that out, and learn to set one 
against the other. That some places you needed 
lawyers to do business for you, but here in 
Northfield you needed ministers, and if you 
didn't have one you were all out of luck. 

He was going to cut down the Gravensteins 
but I told him no, and showed him how to graft 
'em with scions fi-om the Baldwins. The little 
cuss never did it, though, he turned out to be too 
dimab lazy. That old fool was over eighty when 
he broke his hip. It mended good as new. The 
fall would a killed any decent person. And you 
know the saying, "The Good Die Young." Guess 
that's a fact. 



mi^ mi^ %i« «f^ m^ 

0^ 0^ 0^ ^« 0^ 



Fruit Notes, Volume 62 (Number 2), Spring, 1997 



25 




Fruit Notes 



University of Massachusetts 

Department of Plant & Soil Sciences 

205 Bowditch Hall 

Amherst, MA 01003 



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Yuit Notes 

Prepared by the Department of Plant & Soil Sciences. 

UMass Extension, U. S. Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R. Autio and IX^lliam J. Bramlage 




re r: 
BIOLOGICAL^ ^, 

APR 01 1998 1 -^ 



SCIENCE3 LIBRARY 

Volume 62, Number 3 
SUMMER ISSUE, 1997 

Table of Contents 



Effects of Natural Food Sources on Attraction 
of Apple Maggot Flies to Baited Traps 

What Part Do Flyspeck Ascospores Play 
in Disease Development? 

Tax Pointers for Farmers and Landowners in 1997 
and Planning Notes for 1998 

Evaluation of Peach and Nectarine Cultivars 
for Massachusetts Orchards 



Fruit Notes 



Publication Information: 

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July, and October by the Department of Plant & Soil Sciences, University 
of Massachusetts. 

The costs of subscriptions to Fruit Notes are $ 1 0.00 for United States 
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ments must be in United States currency and should be made to the 
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Fruit Notes 

Department of Plant & Soil Sciences 
205 Bowditch Hall 
University of Massachusetts 
Amherst, MA 01003 



UMASS EXTENSION POLICY: 

AH 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 no warranty or guarantee of any kind, expressed or implied, 
concernmg the use of these products. USER ASSUMES ALL RISKS FOR PERSONAL 
INJURY OR PROPERTY DAMAGE. 



Issued by UMass Exlensmn. Robert G. Helf^esen. Direcuir. infunherunre iifthe acts (>l MiiySaiuLlune SU. 
1914. UMass Extension offers eqiiiil opportunity in proi^rams and employment. 



Effects of Natural Food Sources on 
Attraction of Apple Maggot Flies 
to Baited Traps 

Juan Rull, Alan Reynolds, Michelle Balds, HoUy Gagne, and 

Ronald Prokopy 

Department of Entomology, University ofMiissachusetts 



The effectiveness of visually attractive red 
sticky spheres can be increased by the addition 
of odor lures. In recent study in commercial 
orchards by Reynolds and Prokopy (1996), it 
was shown that red sphere traps baited with 
butyl hexanoate (an odor emitted by ripening 
apples) realized a four-fold increase in captures 
of apple maggot flies (AMF) when compared to 
unbaited spheres. However, the addition of 
ammonium carbonate (an odor emitted by 
sources of food) to red sphere traps did not 
enhance capture of flies on baited traps. The 
above study involved trapping wild flies 
entering commercial orchards. Their physi- 
ological state was unknown. 

While the nature of fly attraction to butyl 
hexanoate was clear, the cause underlying lack 
of attractiveness of ammonium carbonate was 
uncertain. In order to reach a better 
understanding of AMF response to both lure 
types, we decided to perform an experiment in 
which flies of known physiological and 
nutritional state (mature protein fed or 
immature protein starved) would be released in 
blocks where different combinations of lures 
would be displayed. Further, all treatments 
would be replicated in blocks where natural 
food sources were added or suppressed. In this 
way, we could assess which synthetic lures are 
attractive to flies of different physiological 
states and whether or not the presence of 
natural food in orchards interferes with 
attraction to lures. 

Materials & Meth(fds 

Four sets of six square blocks of 49 apple 
trees each were selected in four commercial 



orchards, with one set of blocks per orchard. In 
every block, red sticky spheres were positioned 
on every perimeter tree. In two of the blocks, 
sources of butyl hexanoate and ammonium 
carbonate were placed 15 cm away from every 
sphere. In two other blocks, only butyl 
hexanoate was added to spheres. Spheres in 
the remaining two blocks were not lured. One 
block of each lure-type treatment was treated 
with Provado''''^ to prevent buildup of aphid and 
leafhopper honeydew (natural food sources). 
The other block of each lure-type treatment 
received a large amount of bird droppings (also 
a natural food source) that was distributed by 
hand (in slurry form) onto the foliage of each 
tree. Thus, half of the blocks of each treatment 
type had a paucity of natural fly food; whereas, 
the remaining blocks had abundant natural fly 
food. 

Apple maggot flies of known physiological 
state were released into the central tree of each 
block. The flies emerged in our laboratory and 
were subjected either to a diet including 
protein and sugar for 14 days (mature flies) or 
a diet limited to sugar for four days (immature 
flies). When ready to be released, flies were 
marked on the back of the thorax with a small 
dot of paint. Approximately 50 mature flies and 
50 immature flies were released in each block. 
Flies of each physiological state released in 
each block bore a distinct color (12 different 
colors used across all blocks in an orchard). 
Flies captured by the traps in each block were 
counted after four days. The percentage of flies 
recaptured was used to compare response to 
treatments. Wild flies captured in the different 
blocks were also counted and their numbers 
compared. 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



1 



F igure 1 : 


R 


es 


ponse o 


f marked released mature flies 


50 T 


v^ 








o 
<1> 




<D 


45 
40 
35 ' 








^HHi 


1 




-«■ ^^_^ 




D 

c 
(1> 


•o 


2 
a 


20 








' 


1 




1 


1 




o 


D 


(> 


15 - 










Hn 




"9 


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H 




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■ ^fl r^ 




Q. 






5- 
n - 


. 






1^ 


P 


' 


i. 


m iju 










o 
o 


AC+Food 
BH+Food 

-AC-Food 

No lure 
+Food 

ure -Food 








1 

X 
CD 










+ ^ — 










I n: o 

m -^ Z 








BH= Butyl hiexanoote, AC 








= Ammonium carbonate, Food = 








Presence or absence of natural 








sources of food on trees . 



-n 

Percentage of markec c 
flies captured q 


2: R 


esponse of marked released Immature fli 


es 


50 

45 

40 

35 

30 

25 

20 

15 - 

10 - 

5 




y 








HI 


^ ^ 


^H 


i\ 


^M ^ ^ 


m ^H ^H .^^ 


B 

F 


"D 
O 
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U- 

+ 

X 
CO 

H = Butyl 

ood = P r( 


•o 

8 

U- 

1 

o 
< 

+ 

X 
m 

tiexanoc 
Bs ence o 


n T! ^ ^ 
n o O O 
n o O O 
>? £ ^ ^ 

o o 
z z 

ite, AC = Ammonium carbonate, 

r absence of natural sources of 

food on trees 



Results 

Similar to the earlier findings of Reynolds 
and Prokopy {Fruit Notes 61(4): 1-2, 1996) on 
response of wild flies, we found that the 



addition of butyl hexanoate resulted in nearly 
a four-fold increase in capture of released 
mature flies on spheres. Presence of ammo- 
nium carbonate did not add to the attractive- 
ness of traps to mature flies, even in the 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



Figure 3: R esponse of unmarked wild flies 



25 - 



20 



0) -D 

I t 

a> o 
a 



1 5 




BH= B u tyl hex anoate, AC= Ammonium 

carbonate, Food = Presence or absence of 

natural sources of food on trees 



absence of food on the apple trees (Figure 1). 
Response of immature flies to lures and traps 
was much lower than that of mature flies. 
Although the combination of butyl hexanoate 
and ammonium carbonate in the presence as 
well as the absence of food was the trap 
treatment that caught the most immature flies 
(Figure 2), captures were well below those of 
mature flies on traps with lures. Responses of 
wild flies were similar to those of released 
mature flies (Figure 3). Again, captures on 
traps having butyl hexanoate alone were 
nearly four-fold greater than captures on 
unbaited traps. Again, addition of ammonium 
carbonate did not enhance trap capture. 

Conclusions 

Our results support the combined use of 
sticky red spheres and butyl hexanoate lures as 
an alternative to insecticides to control AMF. 
Addition of ammonium carbonate lures did not 



enhance captures of released mature flies or 
wild flies, and its slight enhancement of trap 
captures of immature flies was not great 
enough to justify its use. Presence or absence of 
natural food in orchard blocks had little 
detectable effect on response patterns of either 
released mature, released immature, or wild 
flies. Response patterns of wild flies seem to 
indicate that their populations consisted 
mainly of mature flies. 

Our findings support use of a behavioral 
control strategy based on the employment of 
visually attractive red spheres together with 
butyl hexanoate as an odor lure. 

Acknowledgments 

We are grateful to Stanley Baj, Dana Clark, 
and the Peck brothers for generously allowing 
use of their orchards. This work was supported 
by USDA CSRS NRI grant 95-37313-1890 and 
Cooperative agreement 94-COOP-1-0482. 



vT^ •^ *^ •sL^ *^ 

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Fruit Notes, Volume 62 (Number 3), Summer, 1997 



What Part do Flyspeck Ascospores 
Play in Disease Deveiopment? 

S. Lemer, T. Kliorina, and D. R. Cooley 

Department of Microbiology, University of Massachusetts 



Flyspeck is one of the major summer- 
disease concerns of apple growers in the 
Northeast. Yet for most of the season, there is 
little evidence of the fungus within the orchard. 
In a dry year, signs of infection may not appear 
until as late as August. 

For several years we have been conducting 
investigations aimed at gaining a better 
understanding of the natural biology of this 
fungus. We know that it survives the winter on 
a number of wild hosts that are common to most 
orchard borders such as blackberry, maple, 
grape, Virginia creeper, and red oak. We also 
know that, like the apple scab fungus, it 
produces two types of spores: ascospores in the 
late spring and repeating cycles of conidia or 
asexual spores later in the season. 

However, unlike apple scab, which pro- 
duces its first cycle of spores within the orchard 
where well-timed sprays can control the 
disease, flyspeck ascospores are produced 
primarily in the orchard borders on alternate 
hosts. We wanted to know what part these 
early spores play in disease development later 
in the season. 

The flyspeck spots that form on apples, 
blackberries, and other hosts in late summer 
are pseudothecia, the overwintering structure 
of the organism. By late winter these 
structures have matured and are ready to 
produce spores. In the laboratory, we have seen 
that spore development is driven by both 
temperature and humidity. Humidity must be 
quite high - mature spores are produced at 99% 
humidity but not at 96%. Average tempera- 
tures above 50°F are also necessary for spores 
to develop and mature. In New England, these 
conditions can be met for significant portions of 
the day in the field by late May. 



In the spring of 1997, blackberry canes with 
pseudothecia were gathered weekly from three 
sites in Western Massachusetts from late May 
into July. Fifty pseudothecia from each cane 
were examined microscopically and the 
presence of mature spores was recorded. Table 
1 shows the results of this study. 

The 1997 information conforms with data 
gathered in Amherst during 1996 that showed 
that there is a single period of ascospore release 
that occurs in late spring to early summer. An 
unusually warm, wet spring in 1996 com- 
pressed the period of ascospore maturity to a 
shorter period of time, earlier in the season. 
Apple-tree phenology can be used as an aid to 
predict when this period will occur in a given 
year. 

The ascospores produced on the host plants 
in the orchard borders are released into the air 
but we do not know if they are transported as 
far as the orchard block. 

Even if these initial spores are carried to 
apple trees however, it is likely that the spray 
program aimed at controlling apple scab 
ascospores will also control early-season 
infections of flyspeck. 

Information from Dr. David Rosenberger 
indicates that the broad-spectrum protectant 
fungicides commonly used for scab, Mancozeb 
and Captan, will protect against flyspeck for a 
significant period. Mancozeb used at 1 lb/100 
gal. or Captan SOW at 2 lb/100 gal. will protect 
fruit for at least 21 days or 2.5 inches of rain, 
whichever comes first. Captan SOW at lb/100 
gal. protects for 14 days or 2 inches of rain. If 
the last scab spray of the season contains one of 
these fungicides, and is made in early to mid- 
June, fruit will be protected to late June or 
early July. 



Fruit Notes, Volume 62 (Number .3), Summer, 1997 



Table 1 . Flyspeck 


ascospore maturity 


in relation to apple tree 


jjhenology. 




Site 


First mature spores 


Last mature spores I 


Date 


Apple phenology 


Date 


Apple phenology 


Amherst, 1997 
Shelburne, 1997 
Sterling, 1997 

Amherst, 1996 


May 24 
June 3 
May 20 

May 13 


mid petal fall 

90% petal fall 

full bloom 

late bloom 


July 3 

July 6 

July 10 

May 29 


1 1/8" fruit 

1 1/4" fruit 

1 " fruit 

1/4" fruit 





If infections from the initial cycle of spores 
are not the primary cause of late season 
symptoms in the orchard, then conidia must be. 
We wanted to know if inoculum could be 
building up in the woods and borders, in the 
form of conidia, and moving into the orchard 
sometime later in the summer. 

Previous studies have shown that trees 
closer to the borders have a much higher 
incidence of flyspeck {Fruit Notes 61(2): 1-4, 
1996). But flyspeck symptoms are rarely seen 
before the end of July and have never been seen 
early in the season. 

Based on the fact that there are repeated 
yearly infections of the numerous host plants in 
the orchard border, we knew that ascopores 
germinate in the field and cause infections. The 
typical lifecycle of the fungus begins with the 
ascospore germinating to form a colorless 
mycelium which live off the nutrients of the 
waxy surface layer of its host. Repeating cycles 
of conidia or asexual spores form on this 
mycelium, and then the typical flyspeck 
symptoms appear. 

It is possible that ascospores create local 
infections in the borders and cycles of conidia 
proliferate on these hosts creating a reservoir 
of additional infections and inoculum that can 
move into the orchard block when environmen- 
tal conditions are conducive. We know from 
research conducted by Dr. T.B. Sutton that 
flyspeck conidia are discharged primarily in 
the early morning hours, after periods of high 
humidity or heavy dews or rain, and as the 



levels of high humidity decrease (Sutton, Plant 
Disease 74:643-646, 1990). 

During the summer of 1997 we attempted 
to find out if and when asexual spores or 
conidia were typically present within an 
orchard in Shelburne, Mass. The trees had 
been sprayed following a first-level integrated 
pest management schedule with the last spray 
of Rubigan and Pencozeb occurring on June 4. 
Spore traps were placed within the blackberry 
border, in the first row of trees about seventeen 
feet from the border, and in the third row of 
trees about seventy feet from the border. Spore 
trapping rods were brought back to the 
laboratory and spores counted twice a week 
starting in mid-July. 

Actual numbers of spores caught on the 
traps were too small to analyze statistically. 
However, the number of conidia trapped 
increased dramatically during the second week 
of August, coinciding with an increase in heavy 
morning dews. The first symptoms of flyspeck 
were observed two weeks later on August 31. 
Additional data are needed to be able to predict 
the environmental conditions that will lead to 
an increase in conidial inoculum in the orchard. 
It does seem, though, that there is a period of 
time between the end of primary scab season 
and mid-July to mid-August, particularly in 
dry years, when there are few conidia in the 
blocks and the likelihood of flyspeck infection is 
very low. 

In the orchard where spores were trapped. 



Fruit Notes, Volume 62 (Number 3). Summer, 1997 



the first row of trees was sprayed only on the 
side away from the border. The border side of 
those trees was highly vulnerable to infection 
by ascospores, being unprotected by fungicide 
and in close proximity to the blackberries. Yet 
no flyspeck occurred until late summer, when it 
also occurred on the sprayed side of the trees as 
well as in other blocks in the orchard. This 
coincided with a change in environmental 
conditions that either stimulated the fungus to 
grow or promoted an influx of conidial 
inoculum into the orchard from the borders. 
This supports our contention that ascospores 
play little or no role in direct infections on fruit, 
but instead it is conidia moving from border 
plants that inoculate the crop. 

In summary, flyspeck ascospores form in 



the orchard borders and surrounding woods 
rather than in the orchard. Ascospores are 
released during a single discrete period in the 
late spring and early summer, making it 
possible to relate the period of heaviest 
inoculum dose to apple tree phenology, 
generally 10 to 14 days after petal fall. These 
spores probably cause infections on border 
plants but not on orchard fruit. If any infection 
occur, sprays aimed at controlling scab will 
most likely control them. Therefore, ascospores 
do not seem to play a major role in producing 
the flyspeck symptoms that are seen in late 
summer in Massachusetts, and efforts need to 
be focused on controlling infections caused by 
conidia from mid-July thru harvest. 



•sl^ •^ •J^ •J^ •^ 

•^ #^ 0^ #^ #Y* 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



Tax Pointers for Farmers and 
Landowners in 1997 and 
Planning Notes for 1998 

P. Geoffrey Allen 

Department of Resource Economics, University of Massachusetts 



Tax advice given below is intended as 
general advice and is believed to be correct. It 
does not substitute for a detailed review of the 
circumstances of an individual taxpayer by a 
professional tax practitioner. For more details, 
you and your tax adviser may wish to consult 
the sources referenced in the square brackets 
[thus] (I.R. C. = Internal Revenue Code; Tres. 
Reg. = Treasury Regulations). 

New Legislation 

The Taxpayer Relief Act of 1997 "TRA97" 
(Public Law 105-34) is one of the longest and 
most complex pieces of tax legislation passed by 
Congress. It has been called "mind-numbing" 
by members of the accounting profession. It 
also contains errors and omissions, some of 
which would have been fixed by the Technical 
Corrections Bill, had it been passed before the 
end of the 105"" session of Congress. Many 
provisions become effective January 1, 1998, 
although some, most notably those affecting 
capital gains and sale of a principal residence, 
take effect during 1997. Note that instructions 
given in the Farmers' Tax Guide (Publication 
225) on how to deal with capital gains and 
losses are out of date (or are correct only for 
sales of assets made before May 7, 1997). 
Income averaging that was repealed in 1986 
has been re-instituted in a limited way for farm 
incomes only, starting in 1998. 

Self-employed Health Insurance 
Deduction 

Under the tax act passed in 1996, self- 



employed individuals can deduct fi-om adjusted 
gross income (on line 27 of Form 1040) 40% of 
the amount paid in 1997 for health insurance 
for their spouses and dependents. TRA97 
increases the maximum deduction to 100% by 
2007 and speeds up the rate of increase. The 
part of the insurance premium not deducted is 
allowed as a medical expense on schedule A, 
though this will benefit very few people. [I.R.C. 
§ 16(a)(1)(B)] 

Long-term Care Insurance 

TRA97 applies the rules for the deduction of 
health insurance expenses separately for 
health plans that cover long-term care and for 
those that do not. 

Example: an employed husband might have 
employer-provided coverage that excluded 
long-term care. His self-employed wife could 
obtain long-term care insurance for both of 
them and deduct from adjusted gross income 
the same 40% of the insurance premium as 
shown in the previous section. [I.R.C. § 162] 

Self employment Tax on 
Rental Income 

If you rent farmland to another entity 
(individual, partnership, corporation) you do 
not pay SE tax on the rental income unless: 1 . 
There is an arrangement that you will 
materially participate in the production of 
agricultural or horticultural commodities, and 
2. You actually do materially participate in 
production. The material participation rule 
applies to land only. Rent of personal property 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



used with the land is not subject to SE tax. 
[I.R.C. §§ 1401(a), 1402(a) and (b)] 

Example: Bruce Bullock owns a farm and 
rents out the land for $20,000, buildings for 
$5,000 and machinery for $10,000 to a family 
partnership in which he materially partici- 
pates. He mus pay SE tax on the $20,000 land 
rent but not on the $5,000 building rent. Rent 
on personal property is in general subject to SE 
tax so he must pay SE tax on the machinery 
rental of $10,000. The IRS is not likely to treat 
it as falling under the exception for personal 
property rented with real estate. [I.R.C. § 
1402(a)(1)] Note: If Bruce's wife had owned the 
farm and she was not a member of the 
partnership, then she probably would avoid SE 
tax on the land and building rental. 

Like-kind Exchanges 

Property used in a trade or business, or held 
for investment, that is replaced by similar 
property will be a like-kind exchange if certain 
conditions are met. Any capital gain or loss 
realized on the property given up in a like-kind 
exchange must be deferred and the basis of the 
new property adjusted accordingly. Deferral is 
not elective. [I.R.C. § 1031] Form 8824 is used 
to report the transfer and the basis of the 
property acquired. It should be filed the year 
the exchange takes place. 

Like-kind for real estate is interpreted 
quite broadly. For example, timberland for 
bare land, undeveloped farm land for a 
commercial building. For personal property, 
like-kind has a narrower definition. Automo- 
biles, light general-purpose trucks (under 
13,000 pounds actual unloaded weight) and 
heavy general-purpose trucks are separate 
categories. A trade from one category to 
another is not a like-kind exchange. Any two 
assets that are in the same four-digit SIC 
(Standard Industrial Classification) code are 
like-kind. Farm machinery qualifies since it is 
all in SIC code 3523. However, small farm tools 
and equipment are in several different 
categories. [Treas. Reg. § 1.1031(a)-2] 



Sale of Principal Residence 

Up to $250,000 ($500,000 if married, fihng 
jointly) of gain on the sale of a principal 
residence is excluded from tax if all the 
following requirements are met: 1. The 
taxpayer (or either spouse) owned the home 
for two or more years during the five-year 
period preceding the sale; 2. The taxpayer (or 
both spouses) used the home as personal 
residence for two or more years during the five- 
year period preceding the sale; 3. The taxpayer 
(or neither spouse) has used the new exclusion 
during the two-year period preceding the sale; 
and 4. The sale occurred after May 6, 1997. 

A person who moves house every two years 
could claim the exclusion each time. For sales 
after May 6, 1997, few homeowners should be 
faced with pa5ang capital gains on the sale of 
their home. Form 2119 that was used to 
rollover the gain on sale is no longer needed and 
will be discontinued. (Note to Massachusetts 
homeowners: the Commonwealth still follows 
the Internal Revenue Code of previous years. 
Presumably State tax forms will in future 
include a substitute for Form 2119.) [I.R.C. § 
121. I.R.C. § 1034, containing the rollover 
provisions, has been repealed.] 

If part of the residence was used as an 
office, or for business, and had been 
depreciated, any gain allocated to that portion 
would be subject to capital gains tax. See Table 
1. 

Capital Grain 

Schedule D of Form 1040, which was 23 
lines in 1996 has grown to 54 lines in 1997, 
thanks to the complexities introduced by 
TRA97. Profitable sales of assets held for one 
year or less are short-term gains, whenever 
sold. Profitable sales of assets held for 18 
months or less, sold after July 28, 1997 are 
short-term gains. These are taxed at the same 
rate as ordinary income (maximum of 28%). 
For sales of long-term assets after May 6, 1997 
there are three rates: 28% (or 15% for 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



taxpayers in the 15% bracket) on collectibles 
(works of art, coins, etc.), on recaptured 
depreciation of personal property, and on 
recaptured depreciation on real property that 
exceeds the straight line depreciation amount; 
25% (or 15% for taxpayers in the 15% bracket) 
on the depreciation of real estate taken on a 
straight line basis note this change, all real 
estate depreciation is now recaptured, not 
just the excess over straight line depreciation; 
or 20% (10% for taxpayers in the 15% bracket) 
on all other sales this rate is the basic rate for 
capital gains and losses except for the 
situations described for the higher rate. 
Beginning in 2001, the 20% rate drops to 18% 
(10% drops to 8%) for assets purchased on or 
after January 1, 2001 and then held for five 
years. 

The way to treat capital losses was not clear 
from TRA97. On Schedule D of Form 1040, the 
IRS has followed the anticipated changes in the 
Technical Corrections Bill that still awaits 
passage. Basically, short-term losses, if any, 
are applied first to reduce short-term gains, 
then to reduce long-term gains in the order: 
gains in the 28%, 25%, then 20% group. Long- 
term losses in the 28% group are used against 
the 25%, then the 20% group. Losses in the 20% 
group are set off first against the 28% group, 
then the 25% group. 

Massachusetts capital gains rules are 
different. Gain on property held more than one 
year is taxed at 5% and on property held more 
than two years at 4%. In each succeeding future 
year, the rate will drop one percentage point for 
each additional year that the property is held. 

Alternative Minimum Tax 

If you recently sold a commodity on a 
deferred-payment contract and paid alterna- 
tive minimum tax, you can defer the payment 
for both regular income tax and AMT 
purposes. TRA97 repealed I.R.C. § 56(a)(b), 
effective 1987. You can amend your return for 
any past year that is still open to amendment 
(usually the prior three years). 

Example: You delivered corn to an elevator 
in 1995 and received pajonent for it in 1996. For 



regular income tax purposes, you treated the 
sale as 1996 income. For AMT purposes it had 
to be treated as income in 1995. You paid AMT 
in 1995. You may file amended returns (1040X) 
for 1995 and 1996. 

Alternative Minimum Tax 
Depreciation Aef/ustment 

TRA97 allows the same recovery period for 
both regular tax and (AMT) purposes. 
Previously (AMT) required a longer alternative 
MACRS recovery period. Both regular and 
AMT recovery periods are now the same for 
assets placed in service after 1998. 

Income Averaging /or Farmers 

To give farmers subject to year-to-year 
fluctuations in income some relief, TRA97 
institutes a new code section (I.R.C. § 1301) 
that permits taxpayers "engaged in the 
farming business" (as defined in I.R.C. § 
263A(e)(4)) to average over the three prior 
years all or a portion of their taxable income 
derived fi"om farming. The provision is effective 
for the tax years 1998, 1999 and 2000. An 
eligible taxpayer elects to have all or part of 
farming income averaged. The election is 
irrevocable (cannot be changed by filing an 
amended return in later years). Gains from the 
sale of assets (other than land) "regularly 
used by the taxpayer in the farming business 
for a substantial period" can be averaged also. 
One-third of the amount averaged ("elected 
farm income") is allocated to each of the three 
prior years. Tax of an electing farmer would be 
the tax on the amount remaining after 
allocation (say in 1998) plus the additional 
taxes that would have been paid in 1995, 1996, 
and 1997 if the one-third of elected farm income 
had actually been received in each of those 
years. Presumably, the IRS will develop a tax 
form where the election and the necessary 
calculations can be made. The amount of 
income allocated to prior years stays in those 
years as additional income, reducing the 
benefits from income averaging in succeeding 
years. 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



Septic Credit 

If you own and occupy a principal residence 
in Massachusetts and you incur expenses to 
make your sewer system comply with Title V 
you may claim a credit directly against taxes on 
your Massachusetts return. The credit is 40% 
of the costs up to $15,000 for design and 
construction to repair or replace a failed 
cesspool or septic system. The maximum 
aggregate credit of $6,000 is limited to $1,500 
in any year. Unused credit may be carried 
forward for up to three years. Massachusetts 
Schedule SC must be completed and enclosed 
with the tax return claiming the credit. 

Individual Retirement 
Accounts (JRAsJ 

Several kinds of IRA are now available: 

1. Deductible IRA (input is deducted from 
gross income, output is taxable). The 
maximum amount is $2000 per spouse, the 
amount phases out at higher incomes, and 
the phase-out levels keep changing. Under 
prior law, a spouse not covered by a 
retirement plan could not make a deductible 
IRA contribution if the other spouse was 
covered by a qualified retirement plan. 
TRA97 permits a non-covered spouse to 
make a deductible IRA deduction. No 
contributions may be made after age 70.5 at 
which point required withdrawals must 
begin. [I.R.C. § 408 and § 219(b), (c) and (g)] 

2. Non-deductible IRA (non-deductible input, 
taxable output). Where phase-out rules 
have limited the amount contributed as a 
deductible IRA, non-deductible 
contributions can be made (into the same 
account if desired; Form 8606 must be filed 
and establishes the tax-free basis of the 
non-deductible IRA). 

3. "Roth IRA" (non-deductible input, non- 
taxable output). The Roth IRA will be 
available starting in 1998. It is more 
flexible than existing IRA's. For an 
investment made more than 5 years ago 



and withdrawn after age 59.5, the earnings 
are not taxable. Not subject to the current 
minimum distribution requirements at age 
70.5. Contributions can be made after that 
age. The maximum contribution that can 
be made to a Roth IRA is phased out for 
individuals with AGI between $95,000 and 
$110,000 and for joint filers with AGI 
between $150,000 and $160,000. Only 
taxpayers with AGI of less than $100,000 
are eligible to roll over or convert a current 
IRA into a Roth IRA. In 1998, all or part of 
a current IRA can be rolled into a Roth IRA 
with the income tax spread over a four-year 
period. In no case can contributions to all an 
individual's IRAs for a taxable year exceed 
$2,000. [I.R.C. § 408A] 

Which IRA to choose? At a constant tax rate 
there is no difference to the taxpayer between a 
deductible IRA and a Roth IRA. (The difference 
is to the Government; tax payments are 
accelerated.) If your marginal tax rate will rise 
after retirement, choose the Roth IRA; if it will 
fall, choose the deductible IRA. In general, 
always make a contribution to a deductible IRA 
if you can, then to a Roth IRA, and then to a 
non-deductible IRA. If you want to increase the 
amount you put into a retirement fund over the 
$2000 per year allowed for each person's 
combined IRAs, consider the SIMPLE described 
below. 

SIMPLE Simplified Employee 
Pension IRAs 

Beginning in 1997, small-business 
employers can set up SIMPLE (Savings 
Incentive Match Plan for Employees) retirement 
plans. A self-employed person can set one up 
also. Generally, the SIMPLE plan must be the 
only retirement plan of the employer. 

SIMPLE plans are written qualified 
salary reduction arrangements that allow an 
employee to elect to reduce his or her 
compensation by a certain percentage each pay 
period and have the employer contribute the 
salary reductions to the SIMPLE plan on behalf 
of the employee. Any employee qualifies who 



10 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



Table 1 . Example: Jane Carter used one room (10%) of her personal residence as a home office. She 
purchased the house in 1993 for $120,000 and sold it in June 1997 for $200,000. She lived in the 
house during the four years and took $3,000 depreciation on the business part. Jane has two 
transactions. 



Personal residence portion 



Business portion 



Amount of sale 

(90% of $200,000) 

Cost basis (90% of $ 1 20,000) 



Amount of sale 
$ 1 80,000 ( 1 0% of $200,000) 



$20,000 



Realized and excluded gain 



108,000 


Unadjusted basis (10% of 
$120,000) 


$12,000 






Depreciation 


3,000 






Adjusted basis 




9,000 


72,000 


Recognized (taxable) gain 




11,000 



received at least $5,000 in compensation from 
the employer last year and is reasonably 
expected to make at least that amount next 
year. For 1997, the amount of the employee's 
salary reductions cannot exceed $6,000, 
however it is not subject to percentage 
limitations. Therefore, an employed person 
who has a part-time self-employment activity 
that earns $6,000 could deposit the entire 
$6,000 in a SIMPLE plan. Employers are also 
required to make contributions to the SIMPLE 
plan on behalf of eligible employees, an equal 



match up to 3% of pay of each contributing 
employee or a flat 2% of pay of all employees, 
whether they contribute or not. Contributions 
to a SIMPLE plan are not subject to income tax 
until they are distributed. The IRS has 
provided forms (Form 5303-SIMPLE for use 
with a designated financial institution and 
Form 5304-SIMPLE for use with no designated 
financial institution). These forms are not filed 
with the IRS but form the legal contract 
between employer and employees for 
implementation of the SIMPLE IRA. 



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Fruit Notes, Volume 62 (Number .3), Summer, 1997 



11 



Evaluation of Peach and Nectarine 
Cultivars for Massachusetts Orchards 

Karen I. Hauschild 

Deparfment of Plant & Soil Sciences, University ofMcissachusetts 



As Massachusetts apple growers face in- 
creasing competition from producers worldwide, 
they are turning to retail sales to maintain or 
enhance their economic viability. Additionally, 
the popularity of new apple cultivars has con- 
tributed to the decline in market share for Mcin- 
tosh, the major variety. 

As an alternative to apples, Western Mas- 
sachusetts growers have been especially suc- 
cessful with peaches. They rarely lose a crop to 
cold or frost injury, and have a clientele base 
that is looking for local, tree-ripened fruit. Cen- 
tral and Eastern Massachusetts retail growers 
also grow peaches, but these areas have been 
more likely to experience partial or full crop 
losses due to spring frosts. These growers, then, 
are constantly searching for hardier cultivars. 

For most retail growers, the decision to grow 
or add additional peaches is an easy one. Choos- 
ing cultivars is more difficult. In an effort to 
assist Massachusetts growers with cultivar 
choices, a cultivar trial was established at the 
University of Massachusetts Horticultural Re- 
search Center (HRC), included Flower bud har- 
diness, fruit size, harvest season, and fruit qual- 
ity have been evaluated. 

The first trees in the cultivar evaluation 
trial were planted in 1990, and cultivars were 
added in 1998, 1994, and 1996. Trees were pur- 
chased from commercial nurseries and planted 
in a 10' X 20' spacing. Four-tree plots of each 
cultivar were used. Trees were mananged as 
in commercial plantings. 

Results 

Cultivars included in the trial are listed in 
Table 1 was evaluated following a test winter 
of 1993-4 during which a low of -15EF was re- 
corded at Quabbin Reservoir (approx. 1.5 miles 



north of the HRC). On 4 May 1994, 1 evaluated 
bloom visually on all trees that were planted in 
1990. I estimated bud survival on the top and 
bottom (below 4 feet) half of each tree. Table 2 
lists cultivars that averaged more than 30% bud 
survival. From these results it appears that 
Madison has relatively hardy flower buds. Al- 
though most of the trees in the 1990 planting 
began fruiting in 1991 or 1992, data recorded 
from 1991-96 is incomplete. Fruit quality was 
evaluated yearly, and yield data is available for 
several cultivars during this time, however 

In 1997, at least one 10-fruit sample per cul- 
tivar (except the 1996 planting) was weighed, 
measured, and judged for quality. Table 3 lists 
the most promising cultivars based on size, as 
well as average weight, average size, and har- 
vest date. 

Recommendations 

Of the yellow-fleshed cultivars that met the 
three-inch size criterion determined by grow- 
ers, eight also met the criteria for quality: 
Bounty, Encore, Fayette, Flavorcrest, 
JimDandee, Madison, Salem, and Sentry. Al- 
though the size and quality assessments of both 
Fayette and Encore were very favorable, the har- 
vest timings of both cultivars very likely are 
too late for the majority of growers whose main 
crop is apples. Summer Pearl was the only 
white-fleshed peach that met size and quality 
criteria. It is 75% -i- red to dark red; firm, juicy, 
with sweet, melting flesh. Of the nectarines 
evaluated, Earliscarlet and Fantasia have both 
consistently maintained heavy yields, good size, 
excellent color and exceptional fruit quality. 

Of the cultivars that met the size criteron, 
but did not meet quality standards in 1997, sev- 
eral have shown promise in other years: 



12 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



Table I. List of cultivars by years planted in the Massachusetts Peach Cultivar 
Evaluation Trial. 



Ripening 

Year date relative 

Cultivar planted to Redhaven Type^ 

Jerseydawn 1990 -5 Y 

Redhaven Y 

Salem +6 Y 

Summer Pear! +20* W 



Flavorcrest 






-1-20 


Y 


Newhaven 






+2 


Y 


Madison 






+24 


Y 


Earliscarlet 






-10 


N 


Fantasia 






+31 


N 


Redgold 






+29 


N 


Summer Beaut 






+4 


N 


Bounty 










Encore 






+36 


Y 


Fayette 






+30* 


Y 


Harcrest 






+26* 


Y 


NJ 275 (Ernie's 


Choice) 




+9* 


Y 


Harrow Beauty 






+21* 


Y 


Jim Dandee 






+8* 


Y 


Earlired 




1993 


-19 


Y 


Beekman 






+20 


Y 


JohnBoy 






+4 


Y 


Sentry 






-12 


Y 


Mt. Rose 






+ 15* 


W 


Lady Nancy 






+31* 


W 


Red Rose 






+15* 


W 


Sugar Lady 




1994 


+ 11 


W 


White Lady 






+15 


W 


Eastemglo 






-10 


N 


Sunglo 






+ 12 


N 


PF- 1 (Flaming Fury Series) 


1996 


-20 


Y 


PF-15A 






+ 13 


Y 


PF-17A 






+17 


Y 


Raritan Rose 






+4 


W 


Arctic Glo 






-10 


WN 


Arctic Rose 






+7 


WN 


Arctic Queen 






+28 


WN 


*N = yellow-fles 


hed nectarine; Y = 


= yellow-fleshed 


peach; W = 


white-fleshed peach; 


WN = white-fleshed nectarine. 









Fruit Notes, Volume 62 (Number 3), Summer, 1997 13 







Table 2. Percentage bud survival 


, averaged 










over four trees per cultivar. 










Cultivar 




Lower 


Upper 








Flavorcrest 




25% 


75% 










Newhaven 




10% 


75% 










Earliscarlet 




10% 


50% 










Fantasia 




10% 


60% 










Redgold 




40% 


60% 










Summer Beaut 


10% 


60% 










Madison 




75% 


90% 








- 


Harcrest 




10% 


60% 






Table 3. 


Average size, size range, average 


weight, percentage 


of split pits, and harvest dates for more promising cultivars. | 








Fruit 








Diameter 


weight 


Splits 


Harvest 


Cultivar 




(in.) 


(g) 


(%) 


date 


Jerseydawn 


2.9 


195 


40 


14 Aug. 


Sentry 




3.1 


278 


50 


4 Aug. 


Earliscarlet 


2.9 


202 


22 


15 Aug. 


Newhaven 


2.9 


205 





19 Aug. 


Flavorcrest 


3.0 


209 


20 


19 Aug. 


Bounty 




3.1 


278 


10 


27 Aug. 


Salem 




3.1 


255 


20 


26 Aug. 


Jim Dandee 


3.2 


261 


20 


26 Aug. 


Sugar Lady 


3.0 


231 





26 Aug. 


Mt. Rose 




3.0 


217 





26 Aug. 


White Lady 


3.0 


227 


10 


27 Aug. 


Red Rose 


3.0 


235 





4 Sept. 


Beekman 




2.9 


234 





4 Sept. 


Lady Nancy 


3.1 


232 





10 Sept. 


Madison 




3.2 


259 


20 


15 Sept. 


Fantasia 




3.0 


273 


10 


15 Sept. 


Sum. Pearl 


2.9 


224 





15 Sept. 


Harcrest 




2.9 


207 


10 


15 Sept. 


Redgold 




3.0 


267 


22 


15 Sept. 


Encore 




3.1 


256 





1 Oct. 


Fayette 




3.1 


252 





25 Sept. 





14 



Fruit Notes, Volume 62 (Number 3), Summer, 1997 



Newhaven, Sugar Lady, White Lady, Mt. Rose, 
Harcrest, Redgold, and Summer Beaut. 

Trees in the 1993 planting did not do well. 
They were planted late, and suffered from a dry, 
hot summer. Trees of four of the cultivars in 
this planting were replanted in 1996, and should 
bear enough fruit for evaluation in 1998. 
JohnBoy is one cultivar that should perform 
well. 

Data from the 1990 planting will be collected 
for at least one more year Because the de- 
mand for peaches and nectarines has been high 
at the Horticultural Research Center 
farmstand, these trees will most likely remain 



until other, commercial, plantings come into 
production. Cultivars from all plantings should 
bear fruit in 1998, and data will be collected for 
at least two more seasons from the 1993, 1994, 
and 1996 plantings. 

Acknowledgments 

The author wishes to recognize Mr. Joe 
Sincuk, Mr. Jim Krupa, and the field crew at 
the Horticultural Research Center. This work 
would not have been possible without their as- 
sistance. 



•X» •^ •^ •kl> •sl^ 

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Fruit Notes, Volume 62 (Number 3), Summer, 1997 



15 




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 01002 



1 

SERIAL SECTION 

UNIV OF MASSACHUSETTS LIBRARY 

AMHERST MA 01003 



-^^?€^:>'f5 






Account No. 2-22914 



UM/Morr. 

Per 

SB 

354 

Ffe8 



'rult Notes 



Prepared by the Department of Plant & Soil Sciences. 

UMass Extension, U. S. Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R. Autio and William J. Braxnlage 



BIOLOGICAL s 

CO 



— :s3 

vJD •V>. 




MAY 2 1 1998 

SCIENCES LIBRARY 

Volume 62, Number 4 
PALL ISSUE, 1997 

Table of Contents 



Tests of Imidacloprid-treated Spheres 
for Controlling Apple Maggot Fly 



A Preliminary Study of 1PM Options for Peaches: Brown Rot 

Establishment and Spread of Released Typhlodromus pyri Predator 
Mites in Apple Orchard Blocks of Different Tree Size: 1997 Results 

An Update on the 1991 Mcintosh Strain/Rootstock Trial 

Comparison of Ladd Traps, Red Spheres, and Yellow Panels for 
Capturing Apple Maggot Flies in Commercial Apple Orchards 

Can We Predict Flyspeck Development? 



Fruit Notes 



Publication Information: 

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

The costs of subscriptions to Fruit Notes are $ 1 0.00 for United States 
addresses and $ 1 2.00 for foreign addresses. Each one-year subscription 
begins January 1 and ends December 3 1 . Some back issues are available 
for $3.00 (United States addresses) and $3.50 (foreign addresses). Pay- 
ments 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 01 003 



I 



UMASS 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 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 UMass Exleiisinii. Ruben G Hetjtesen. Direclnr, in lurlberance of the iicis of May H and June 30, 
1914. UMiiss Extension offers equal apparlunily in pnif;ianis and empliiynienl. 



Tests of Imidacloprid-treated Spheres 
for Controlling Apple Maggot Fly 



Starker Wright, Xing Ping Hu, and Ronald Prokopy 
Department of Entomology, University of Massachusetts 



In the 1996 and 1997 Spring issues oi Fruit 
Notes, we reported on studies aimed at devel- 
opment of pesticide-treated spheres (PTS) as a 
substitute for sticky spheres for direct control 
of apple maggot flies. In concept, a PTS would 
be coated with a mixture of insecticide, fly feed- 
ing stimulant, and residue-extending agent. A 
fly landing on such a sphere would feed, ingest 
insecticide, and die before laying any eggs. The 
need to use labor-intensive sticky substances 
(such as Tangletrap) to capture alighting flies 
would be eliminated. Several earlier trials in- 
dicated that dimethoate was the most effective 
among orchard-labeled insecticides for use on 
spheres, but its high human toxicity poses too 
great a risk to the handler. In 1996, we found 
that the newly-labeled insecticide imidacloprid 
was a safer alternative to dimethoate and was 
seemingly as effective. 

Sucrose (table sugar) has proven to be, by 
far, the most effective fly feeding stimulant. 
However, while mixing with latex paint pre- 
serves the residual activity of the insecticide, 
all sugar is lost from the sphere surface follow- 
ing rainfall. We have taken two separate ap- 
proaches to preserving residual activity of su- 
crose: (1) development of a method in which 
the activity of sucrose is extended on reusable 
wooden spheres, which are annually coated with 
a mixture of sucrose, insecticide, and latex paint; 
and (2) development of a method in which the 
entire sphere body is constructed of a mixture 
of sucrose, flour, and glycerin, coated with a mix- 
ture of insecticide and latex paint so as to cre- 
ate a biodegradable sphere. Here we report on 
two experiments leading to refinement of resi- 
due-extending agent, fly-killing agent, and 
evaluation of each sphere type for direct con- 
trol of apple maggot flies in commercial or- 
chards. 



Materials & Methods 

In our first experiment, we evaluated in 
laboratory studies three formulations of 
imidacloprid (EC, WP, technical grade) in com- 
bination with each of three formulations (flat, 
semi-gloss, gloss) of each of four commercial 
brands of red latex paint (36 treatments in all). 
We found the EC and WP formulations of 
imidacloprid in Glidden Red Latex Gloss 
Enamel paint to be the most promising. We then 
placed wooden spheres coated with two concen- 
trations of each formulation of imidacloprid in 
orchard trees and evaluated them for their abil- 
ity to kill apple maggot flies at 0, 3, 6, 9, and 12 
weeks after placement. 

In our second experiment, two sphere types 
were assessed in an attempt to extend the re- 
sidual activity of sucrose on the sphere surface. 
Each wooden PTS was fitted with a 3-cm-di- 
ameter ring of specially formulated caramelized 
sucrose around the hook at the top of the sphere. 
The sucrose spread down the sides of the sphere 
after each rainfall, continually replenishing the 
sugar supply on the sphere surface. This type 
of sphere was developed as a replacement for 
spheres tested in 1996 in which holes were 
drilled and filled with sucrose prior to paint- 
ing, as described in the Spring 1997 issue of 
Fruit Notes. Further testing of the 'spheres with 
holes' revealed that construction was far too 
costly and time consuming to be of practical 
value. For sugar/flour biodegradable spheres, 
the following composition of ingredients proved 
best: sucrose/fructose syrup (25%), 
pregelatinized corn flour (25%), wheat flour 
(25%), glycerin (10%), and water (15%). After 
hardening in the laboratory, such spheres emit 
a continuous supply of sugar to the surface, ir- 
respective of rainfall amount. 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



We then compared the effectiveness of our 
best wooden PTS and our best sugar/flour PTS 
with sticky-coated spheres for direct season- 
long control of apple maggot flies in commer- 
cial orchards. In all, we used eight orchards, 



each having four blocks of medium-sized trees 
(49 trees/block). Each block receiving spheres 
was surrounded by 26 spheres of the same type, 
five yards apart, each baited with butyl 
hexanoate. 



Table 1. Residual activity 
concentrations of imidaclopric 
orchard trees and exposed to w 


of two different formulations and two different 
in latex paint on sucrose-treated spheres hung in 
eather. 


Fly mortality (%)* 


Weeks of 
Exposure 


0.5% EC 


1.5% EC 


0.5% WP 


1.5% WP 


Check 





97a 


97a 


96a 


98a 


Ob 


3 


96a 


93a 


90a 


95a 


3b 


6 


70b 


92a 


85a 


94a 


5c 


9 


60b 


90a 


80a 


90a 


Oc 


12 


45c 


87ab 


75b 


90a 


5d 


No. eggs laid in artificial fruit* 





Oa 


Oa 


Oa 


Oa 


26b 


3 


Oa 


Oa 


Oa 


Oa 


28b 


6 


2a 


Oa 


2a 


Oa 


25b 


9 


la 


Oa 


2a 


Oa 


21b 


12 


la 


Oa 


Oa 


Oa 


24b 






Median lethal feeding time* 







30a 


20a 


30a 


20a 


- 


3 


80b 


40a 


75b 


35a 


- 


6 


182b 


45a 


180b 


40a 


- 


9 


240b 


50a 


210b 


45a 


- 


12 


300c 


100a 


240b 


60a 


- 


* Three replicates of 20 flies per treatment. Numbers 
different letters are significantly different at odds of 19:1. 


within rows 


followed by 



Fruit Notes, Volume 62 (Number 4), Fail, 1997 



Table 2. Control of apple maggot flies by odor-baited wooden pesticide treated 
spheres (PTS), sugar/flour PTS, sticky spheres or three applications of 
azinphosmethyl in blocks of apple trees in commercial orchards. 



Mean % maggot-injured apples'* 



Wooden 
PTS 



Sugar/flour 
PTS 



Sticky 
Spheres 



Azinphosmethyl 



0.56b 



0.32ab 



0.32ab 



0.11a 



* Total of 2800 fruit per treatment (100 fruit per block on each of four sampling 
dates-2 weeks apart-from late July until harvest). Numbers followed by a different 
letter are significantly different at odds of 19:1. 



Results 

Laboratory bioassays revealed (Table 1) that 
after 12 weeks of exposure to outdoor sunlight 
and 11 inches of natural rainfall, wooden 
spheres treated with 1.5% a.i. imidacloprid WP 
in Glidden paint killed 90% of arriving flies. 
Such treatment also rendered all flies incapable 
of lajdng eggs after feeding and required that a 
fly feed on the sphere surface for a median time 
of only 60 seconds to ingest enough toxicant to 
die. Performance of wooden spheres treated 
with 1.5% imidacloprid EC was slightly but not 
significantly inferior, killing 87% of arriving 
flies. At lower concentrations (0.5% a.i.), nei- 
ther the WP nor EC formulation performed as 
well (75% and 45% kill, respectively) as the 1.5% 
a.i. WP formulation. 

In our second experiment (Table 2), sugar/ 
flour PTS coated with 1.5% imidacloprid WP in 
Glidden paint performed as well as sticky 
spheres in providing direct control of apple 
maggot. Wooden PTS coated with 1.5% 
imidacloprid in Glidden paint and fitted with a 
3-cm-diameter sucrose ring were inferior Two- 
to-three insecticide sprays resulted in the least 
damage. 



Conclusions 

Our first experiment provided us with the 
formulation of a low dose of a safe and highly 
effective insecticide (1.5% a.i. imidacloprid WP) 
that can be combined with a particular type of 
paint (Glidden Red Latex Gloss Enamel) which 
offers very long and effective residual activity 
of imidacloprid under field conditions. 

Although all sphere types used in the sec- 
ond experiment performed quite well in the face 
of high fly pressure, shortcomings need to be 
addressed and improvements need to be made 
before future use of PTS for controlling apple 
maggot in commercial orchard IPM blocks. 
Regarding wooden PTS, the caramelized sucrose 
rings melted away before the end of the field 
season, contributing to the reduced effective- 
ness of these spheres. Some of the sugar/flour 
PTS were eaten by birds and rodents while oth- 
ers were overgrown by fungi on the sphere sur- 
face, thus reducing the number of effective 
spheres comprising the barrier to fly entry into 
some blocks. 

For 1998 deployment of wooden PTS, we 
plan to reformulate the sucrose ring atop the 
sphere to improve residual effectiveness of the 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



spheres. For sugar/flour biodegradable PTS, we 
will evaluate various bird/rodent-feeding deter- 
rents and various fungicides incorporated into 
the body of the sphere. 

Acknowledgments 

This work was supported by state/federal 



IPM funds and grants from the New England 
Tree Fruit Growers Research Committee and 
the USDA Northeast Regional IPM Competi- 
tive Grants Program. We are grateful to the 
eight growers that participated in this study: 
Bill Broderick, Dana Clark, Dave Chandler, 
Tony Lincoln, Wayne Rice, Dave Shearer, Joe 
Sincuk, and Tim Smith. 



*\a •Jt* •X^ •Xa •Xa 
ry% #Y* *T* *T* *T* 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



A Preliminary Study of IPI\/I Options for 
Peaches: Brown Rot 

Daniel Cooley and Arthur Tuttle 

Department of Microbiology, University of Massachusetts 



Karen Hauschild and Joe Sincuk 

Department of Plant & Soil Sciences, University of Massachusetts 



Peaches have gained more attention from 
Massachusetts tree-fruit growers, who in 
recent years have been looking for crop options 
in addition to apples. Peaches can produce 
highly saleable fruit earlier in the season, and 
usually command a good price, particularly for 
direct market sales. High quality peaches 
which have been allowed to ripen on the tree 
longer than peaches shipped from California, 
New Jersey, or the South can get a premium 
price. However, the riper a peach is, the higher 
the chances are that it will develop brown rot or 
other postharvest decays. This may happen on 
the tree, or worse yet, on the customer's shelf. 
While other rots can be a problem, peach brown 
rot, caused by the fungus Monilinia fruciico/a, 
is the most serious fungal disease problem for 
Massachusetts growers, and fungicides used on 
peaches primarily are aimed at managing this 
disease. The timing of these fungicide 
applications is based largely on tree develop- 
ment, but it is not clear what timing scheme is 
most effective and efficient. 

The biology of the fungus suggests that 
there are two critical times when peaches 
should be protected: bloom and fruit ripening. 
Brown rot infections on peach develop during 
these two phenological stages. Blossom blight 
may cause flowers to wither, turn brown, and 
die, and later produce spores which later infect 
fruit. These blossom infections may also move 
into twigs and cause significant damage when 
conditions for disease development are highly 
favorable. Normally blossom infections remain 
quiescent, or latent, until fruit starts to ripen. 



Then, the infections will start to grow, produce 
spores, and spread to other ripe fruit. Between 
bloom and harvest, fruit susceptibility to 
brown rot remains quite low from pit hardening 
to 2 weeks before full ripeness (Biggs and 
Northover, 1988). By monitoring pit hardening 
and ground color, growers might eliminate 
fungicide sprays during this period, and get 
better brown rot control. 

Materials & Methods 

To examine the effect of reducing fungicide 
use for managing brown rot during pit 
hardening, an experiment was conducted at the 
University of Massachusetts Horticultural 
Research Center during the 1996 growing 
season. The experiment was conducted in two 
blocks of peaches, one Redhaven and the other 
Glohaven. Each treatment plot consisted of 
three trees. There were three replications of 
the experiment in the Redhaven block and four 
in the Glohaven block. 

Sampling for pit hardening was done in 
mid- through late June. Until pit hardening in 
early June, all treatment plots received 
standard calendar-based fungicide applica- 
tions every 7 to 10 days, starting at early bloom. 
These consisted Captan 80WP at 1 lb/100 gal. 
After that time, fungicides were applied 
according to four treatment patterns. In one 
treatment, the calendar applications were 
continued at 7 to 14 day intervals, using 
Captan (SOW, 1 Ib./lOO gal.) on the early spray 
dates or the same rate of Captan plus Benlate 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Table 1. Fungicide treatments in Redhaven 
Massachusetts Horticultural Research Center, B( 


and Glohaven 
jlchertown, MA, 


peach 
1996. 


3s at 


the 


University of 


Pesticide (rate/100 gal.) 




Dates 




Fungicide applications 
after pit hardening 
(no. after 10 July) 


Full spray 
















Captan 


SOWPdlb.) 


17 June, 2 July, 14 July 






3 


Captan 


80WP + Benlate 50DF (6 fl oz.) 




25 July, 2 Aug. 








2 


Reduced spray 














Captan 


SOWPdlb.) 




2 July, 14 July 








2 


Captan 


80WP + Benlate 50DF (6 fl oz.) 




2 Aug. 








1 


Low spray 
















Captan 


SOWPdlb.) 




2 July 








1 


Captan 


80WP + Benlate 50DF (6 fl oz.) 




2 Aug. 








1 


No spray 
















None 






none 











1 



(50DF 6 fl oz./lOO gal.) on later dates. In a 
second treatment, one fungicide application 
was made between pit hardening and fruit 
ripening, with one additional fungicide applica- 
tion during fruit ripening using the same 
fungicides and rates. In the third treatment, no 
fungicide applications were made following pit 
hardening and one fungicide application was 
made during fruit ripening using the same 
fungicides and rates. A fourth treatment was 
not sprayed at all. These treatments with the 
numbers and dates of applications are detailed 
in Table 1. 

Redhaven fruit were harvested on 15 and 2 1 
Aug.; Glohaven fruit were harvested on 3 Sept. 
Therefore, the last fungicide applications were 
made from 2 to 4 weeks before harvest, 
depending on the cultivar, and 2 to 4 weeks 
after pit hardening. Therefore the experiment 
evaluated the effect of different numbers of 
fungicide sprays applied during pit hardening. 



from no sprays to five sprays. 

Evaluation of fruit rot damage was done at 
harvest, and 5 to 7 days after harvest. Brown 
rot and other rots were distinguished on the 
basis of symptoms. Disease incidence is the 
number of fruit which show any disease. 
Disease severity estimates the extent of fruit 
rot using a 1 to 5 scale, with 1 the least severe 
and 5 the most severe. 

Results & Discussion 

The number of fungicide applications after 
pit hardening but before ripening had an effect 
on brown rot and other rots, but it was not 
consistent. In Redhaven fruit at harvest, there 
was significantly less rot in the full spray and 
reduced spray treatments compared with the 
low spray treatment (Table 2). However, the no 
spray treatment also had significantly less 
brown rot at harvest compared with the low 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Table 2. Disease evaluations on Redhaven 
schedules, University of Massachusetts Hortic 


peach fruit under different pesticide 
ultural Research Center, 1996.* 


treatment 




At harvest 




Postharvest 


Brown rot 
incidence 
Treatment (%) 


Brown rot 
severity 


Incidence 
of other 
rots (%) 


Severity 

of other 

rots 


Brown rot 
incidence 

(%) 


Incidence 
of other 
rots (%) 


Full spray 2 b 
Reduced spray 4 b 
Low spray 8 a 
No spray 4 b 


0.02 c 
0.11b 
0.19 a 
0.07 c 


Ob 
Ob 
2a 
Ob 


0.01 b 
0.00 b 
0.05 a 
0.00 b 


24 b 
21b 
31b 
49 a 


14 a 

21 a 

14 a 

9 a 


* Severity; 1 = least severe, 5 = most severe. Means in each 
not differ significantly from each other at odds of 19:1. 


column followed by the same letter do 



Table 3. Disease evaluations on Glohaven peach fruit under different pesticide treatment 
schedules, University of Massachusetts Horticultural Research Center, 1996.* 







At harvest 




Postharvest 




Brown rot 




Incidence 


Severity 


Brown rot 


Incidence 




incidence 


Brown rot 


of other 


of other 


incidence 


of other 


Treatment 


{%) 


severity 


rots (%) 


rots 


(%) 


rots (%) 


Full sprays 


7c 


0.18 c 


1 a 


O.Ola 


37 a 


20 a 


Reduced spray 


20 b 


0.52 b 


1 a 


O.Ola 


60 a 


28 a 


Low spray 


10 c 


0.30 c 


2 a 


0.02 a 


32 a 


12 a 


No spray 


48 a 


1.30 a 


1 a 


0.01 a 


58 a 


36 a 



* Severity: 1 = least severe, 5 - most severe. Means in each column followed by the same letter 
do not differ significantly from each other at odds of 19:1. 



spray regime. Approximately one week after 
harvest, none of the sprayed treatments had 
significantly different brown rot incidences. 



and all were lower than the no spray treatment. 

In Glohaven fruit, the pattern was closer to 

what one would expect (Table 3). At harvest, 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



the no spray treatment had more brown rot and 
more severe brown rot than any of the spray 
treatments. Again, brown rot was lowest in the 
full spray trees. However, in this cultivar, 
brown rot was just as low in the low spray 
treatment, and significantly higher in the 
reduced spray treatment. 

Unfortunately, this test did little to resolve 
the usefulness of fungicides during the period 
between pit hardening and harvest. None of 
the reduced-spray options consistently did as 
well as the five-spray program. It is difficult to 
explain the failure of two fungicide applica- 
tions vs. no applications in Redhaven, and of 
three applications vs. two applications in 
Glohaven. It is possible that there was 
contamination caused by fungicide drift. 
Beyond that, there may have been differences 
in inoculum or other factors which were not 
adequately controlled. 



This test did not conform to the recommen- 
dations made by Biggs and Northover. Rather 
than eliminating or reducing sprays after pit 
hardening, and then making one or two 
applications very near harvest as fruit ripened, 
this test looked at different numbers of 
fungicide applications made after pit harden- 
ing but stopping all fungicides at least two 
weeks before harvest. This may account for the 
results, as Captan and Benlate would not 
generally persist for more than a week against 
heavy brown rot pressure. Any small, random 
outbreak of brown rot would have been able to 
spread in all treatments during the 2 to 3 
unprotected weeks before harvest. Only the 
heaviest fungicide treatment consistently 
reduced this problem. 

A similar experiment, focusing on bloom 
and harvest fungicide applications, will need to 
be done to resolve these problems. 



•sL* vj> vL* vl>» vL* 
#Y* *T* "T* *T* *Y* 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Establishment and Spread of Released 
Typhlodromus pyri Predator Mites in 
Apple Orchard Blocks of Different Tree 
Size: 1997 Results 



Ronald Prokopy, Starker Wright, and Jonathan Black 
Department of Entomology, University of Massachusetts 

Jan Nyrop, Karen Wentworth, and Carol Herring 

Cornell University, NY Agricultural Expe?ime?it Station, Geneva 



Pest mites are usually completely controlled 
by predatory mites on unmanaged apple trees 
that receive no insecticide or fungicide. Some 
commonly-used orchard pesticides (e.g., 
synthetic pyrethroid insecticides, EBDC 
fungicides) kill or otherwise harm predatory 
mites, leading to pest mite outbreaks and need 
for miticide application. In Massachusetts, the 
predatory mite Amblyseius fallacis is present 
in about 90% of commercial orchards (see 1994 
Spring issue oi Fruit Notes) but usually not in 
numbers sufficient for providing mite biocontrol 
until August. Studies in New York have shown 
that the predatory mite Typhlodromus pyri, 
where established, can be an extremely 
effective season-long biocontrol agent of pest 
mites. This is a result of their ability to endure 
cold winter temperatures and periods of short 
supply of pest mites as food much better than^. 
fallacis. Unfortunately, few Massachusetts 
orchards appear to harbor significant natural 
populations of T. pyri. 

In the 1997 Spring issue oi Fruit Notes, we 
reported that when T. pyri obtained from 
Geneva, New York were released in 1995 into 
blocks of apple trees in six commercial orchards 
in Massachusetts, they became established in 
all blocks save those in one of the six orchards. 
On average, after two years, they had built to 
greater numbers in blocks managed under 
second-level IPM practices (no pesticide of any 



type used after early June) than in blocks 
managed under first-level IPM (sprayed with 
fungicide and insecticide through summer). 
These findings stimulated us to conduct 
further research on the establishment oiT.pyri 
released in Massachusetts apple orchards. 

We report here first-year results of a study 
in which T.pyri were released in 1997 on single 
trees in the center of blocks comprised of small, 
medium, or large trees and managed under 
third-level IPM practices. 

Materials & Methods 

Our experiment was conducted in six blocks 
of apple trees in each of eight commercial 
orchards. Of the six blocks per orchard, two 
each contained trees on M.9, M.26, or M.7 
rootstock, designated as small, medium-size, or 
large trees. One block of each pair received 
first-level IPM practices, wherein growers 
applied insecticide and fungicide materials of 
their own choosing and timing of application, 
which extended from April through August. 
The other block of each pair received third-level 
IPM practices, wherein the intent was that no 
synthetic pjrrethroid insecticide was to be used 
at any time, use of EBDC fungicides was to be 
minimized, no insecticide of any type was to be 
used after mid June, and captan or benomyl 
were the only fungicides to be used after mid 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



June. T. pyri is known to be highly adversely 
affected by synthetic pyrethroid insecticide and 
also adversely affected by EBDC fungicide 
(when applied from bloom onward) but not by 
captan or benomyl. Each block was comprised 
of 49 trees (7 rows x 7 trees per row) and of the 
cultivars Mcintosh, Empire, and Cortland. 
Third-level IPM is similar to second-level IPM 
in focus on using biologically-based pest 
management practices, but it embraces 
integration with horticultural concerns (such 
as tree size) as an added component. 

In May, blossom clusters harboring T. pyri 
were picked from an orchard at the New York 
State Agricultural Experiment Station at 
Geneva, sent by overnight mail to 
Massachusetts, and within three days were 
distributed to orchard blocks. Each third-level 
IPM block recieved 100 clusters, which were 
attached to twigs on the center tree of the block 
using twist ties. No T. pyri were released in 
first-level IPM blocks. Every 3 weeks from late 
July through early September in each of the 48 
blocks, we sampled 25 leaves from the center 
tree, 15 leaves from each of the two outermost 
trees in the center row, and 15 leaves each from 
the center tree in each of the two outermost 
rows. The leaves were sent by overnight mail to 
Geneva, New York for the identification and 
counting of pest and predatory mites. In all, 
about 2,600 leaves were sampled for each of the 
three sampling periods. 

Results 

As shown in Table 1, significantly more T. 
pyri-were present on the center (release) tree on 
each sampling date in blocks of each tree size 
than on outer trees in center rows of blocks 
(that is, the fourth tree up row and the fourth 
tree down row from the center tree in a block) or 
on center trees in outer rows of blocks (that is, 
the fourth tree directly across row to either side 
of the center tree of a block). In fact, extremely 
few or no T. pyri were found on any tree except 
those on which they were released. In contrast, 
there were no significant differences among 
tree locations within plots in numbers of A. 
fallacis sampled on each sampling date in 



blocks of each tree size (data not shown). The 
same was true for European red mites (data not 
shown). 

The finding that, on average, numbers of 
European red mites were not significantly 
fewer on release trees than on non-release trees 
on any sampling date in blocks of any tree size 
suggests that T. pyri were not able to build to 
sufficient numbers to provide biocontrol of 
European red mites during the three months 
following release. This was not a surprising 
result because T. pyri populations grow slowly 
and usually are not capable of rapidly 
controlling moderate to high density red mite 
populations. Even so, there was one block of 
small trees in which T. pyri were released 
where every tree (save one) in that block (as 
well as every tree in each of the other five study 
blocks in that orchard) was heavily bronzed as 
a consequence of mite injury. The only tree that 
was not bronzed was the center tree on which T. 
pyri were released. 

Data in Table 2 summarize information of 
all leaves sampled in a block and compare 
average numbers of T. pyri, A. fallacis and 
European red mites per leaf between first-level 
IPM blocks and third-level IPM blocks and 
among small, medium, and large trees within 
each sampling date. For each sampling date, 
there was no significant difference among 
blocks of small, medium-sized, and large trees 
in numbers of 7! pyri found in third-level IPM 
blocks. In every case, third-level IPM blocks 
had significantly more T. pyri than first-level 
IPM blocks. For A. fallacis there were no 
significant differences in numbers found 
between first-level and third-level IPM blocks 
or among tree sizes for any sampling date. The 
same was true for European red mites. 

Information on type and amount of 
insecticide, acaricide, and fungicide used 
before bloom, from bloom through mid-June, 
and after mid- June is given in Table 3. Blocks 
of small, medium, and large trees in the same 
orchard were treated in the same manner. 
With respect to insecticide, some Asana was 
used before bloom and some Lorsban after mid- 
June in first-level blocks. Both of these 
materials are known to be detrimental to T. 



10 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Table 1. Abundance of T. pyri mite predators on leaves sampled in July, August, and September 
in 1997 from first-level and third-level IPM blocks. T. pyri were released on the center tree in 
each block in mid-May 1997. 



Mean no. per leaf ' 



Sample time 



Tree size Sample site 



First-level 1PM Third-level IPM 



Late July 



Mid-August 



Large 



Medium 



Small 



Large 



Medium 



Small 



Early September Large 



Medium 



Small 



Center tree 


0.00 b 


0.34 a 


Center row, outer trees 


0.01 b 


0.01b 


Outer row, center trees 


0.00 b 


0.00 b 


Center tree 


0.03 b 


0.54 a 


Center row, outer trees 


0.00 b 


0.00 b 


Outer row, center trees 


0.00 b 


0.00 b 


Center tree 


0.00 b 


0.68 a 


Center row, outer trees 


0.00 b 


0.09 b 


Outer row, center trees 


0.00 b 


0.00 b 


Center tree 


0.00 b 


0.62 a 


Center row, outer trees 


0.00 b 


0.01b 


Outer row, center trees 


0.00 b 


0.01b 


Center tree 


0.00 b 


1.13 a 


Center row, outer trees 


0.00 b 


0.00 b 


Outer row, center trees 


0.00 b 


0.00 b 


Center tree 


0.00 b 


0.97 a 


Center row, outer trees 


0.00 b 


0.00 b 


Outer row, center trees 


0.00 b 


0.00 b 


Center tree 


0.00 b 


0.87 a 


Center row, outer trees 


0.07 b 


0.01 b 


Outer row, center trees 


0.01b 


0.00 b 


Center tree 


0.00 b 


0.67 a 


Center row, outer trees 


0.00 b 


0.01b 


Outer row, center trees 


0.00 b 


0.00 b 


Center tree 


0.00 b 


0.55 a 


Center row, outer trees 


0.00 b 


0.00 b 


Outer row, center trees 


0.00 b 


0.01b 



* For each size of tree at each time of sampling, numbers followed by a different letter are 
significantly different at odds of 19:1. 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



11 



Table 2. Abundance of T. pyri, A. fallacis, and European red mites (ERM) on leaves sampled in July, 
August, and September in 1997 from first-level and third-level IPM blocks. 











Mean num 


ber per leaf* 








T. 


pyri 


A. fallacis 


ERM 




1^' level 


S'^'' level 


1"' level 


S-^d level 


1«' level 


3^d level 


Sample time 


Tree size 


IPM 


IPM 


IPM 


IPM 


IPM 


IPM 


Late July 


Large 


0.00 b 


0.12 a 


0.04 a 


0.04 a 


3.6 a 


7.2 a 




Medium 


0.01b 


0.18 a 


0.08 a 


0.10 a 


3.3 a 


4.9 a 




Small 


0.00 b 


0.26 a 


0.05 a 


0.07 a 


8.8 a 


5.7 a 


Mid-August 


Large 


0.00 b 


0.21a 


0.06 a 


0.15 a 


9.9 a 


9.0 a 




Medium 


0.00 b 


0.38 a 


0.43 a 


0.36 a 


9.6 a 


2.6 a 




Small 


0.00 b 


0.33 a 


0.11a 


0.24 a 


4.0 a 


10.4 a 


Early September 


Large 


0.01b 


0.21a 


0.15 a 


0.17 a 


2.9 a 


1.3 a 




Medium 


0.00 b 


0.26 a 


0.15 a 


0.17 a 


1.0 a 


3.3 a 




Small 


0.00 b 


0.26 a 


0.09 a 


0.13 a 


1.4 a 


4.5 a 



* Each value represents the average number of individuals found on 55 leaves per block per sampling 
date (25 leaves from the center tree and a total of 30 leaves from four other trees in the blocks, all of 
which were four trees removed from the center tree). For each tree size at each time of sampling, 
numbers followed by a different letter are significantly different at odds of 19:1. 



pyri. The fact that they were not used in third- 
level blocks undoubtedly aided in establishment 
of T. pyri. None of the acaricides used in either 
first-level or third-level blocks is known to 
affect T. pyri substantially. As hoped, none of 
the third-level blocks received any Manzate, 
Dithane, Mancozeb, or Penncozeb as fungicides, 
whereas first-level IPM blocks received 
substantial amounts of these materials up to 
mid-June. Third-level IPM blocks did, 
however, receive some Polyram before bloom 
and a small amount after bloom. Some data 
indicate that Polyram is just as harmful to T. 
pyri as the other four aforementioned EBDC 
fungicides, which are especially harmful when 
applied during or after bloom. In general, the 
profile of fungicides applied in third-leve) IPM 



blocks was quite (although not completely) 
conducive to establishment of T. pyri. 

Conclusions 

The data presented here show convincingly 
that T. pyri became established on trees in 
which they were released: the centermost trees 
in third-level IPM blocks of small, medium, and 
large trees. Growers participating in this 
experiment cooperated with its aims by not 
applying harmful insecticides or acaricides and 
by minimizing use of fungicides harmful to T. 
pyri in the blocks in which T. pyri were 
released. Interestingly, even more than three 
months after release, T. /?>//■/ failed to move (in 
detectable numbers) even as far as four trees 



12 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Table 3. Types and dosage equivalents of insecticides, acaricides, and fungicides applied per 
block in first-level and third-level IPM blocks in 1997. 



Material 



Before bloom 



1^^ level S-^"* level 



Bloom through 
mid-June 



Insecticide 



Acaricide 



Fungicide 



Asana 

Dimethoate 

Gution 

Imidan 

Lorsban 

Provado 

Sevin 

Oil 

Savey 

Silwet 

Agrimek 

Pyramite 

Omite 

Benlate/Topsin 

Nova/Rubigan 

Manzate* 

Polyram 

Syllit 

Captec 



0.06 


- 


0.08 


0.08 


0.04 


0.20 



3.10 



0.12 
1.10 



3.20 



0.12 
1.00 



1.25 
0.50 
0.13 



1.25 
0.38 
0.13 



0.08 



0.08 



0.13 
0.42 
1.75 
0.21 
0.01 



0.13 
1.54 

0.46 
0.60 



0.61 


0.61 


0.34 


1.28 


0.72 


- 


1.05 


0.28 


0.16 


0.01 


0.73 


1.7 



After mid-June 



1^<- level 3'''' level 1" level 3"^ level 



1.00 
0.13 
0.26 

0.06 



0.16 



0.06 



0.67 


1.2 


0.15 


0.13 


0.17 


- 


0.55 


0.26 


0.04 


- 


0.13 


- 


1.15 


0.88 



* Includes also Dithane, Mancozeb, and Penncozeb. 



away downrow or crossrow, regardless of 
whether blocks were comprised of small, 
medium-size or large trees. We saw no 
evidence of suppression of European red mites 
by released T. pyri in any trees (except one) in 
which T. pyri were released. In the lone 
exception (a block of small trees), the foliage of 
the release tree remained dark green throughout 
summer, whereas the foliage of all other trees 
in the block was decidedly bronzed by mid-July. 
For 1998 and 1999, we plan to sample the same 
trees sampled in each block in 1997. We expect 
that by 1999, T. pyri will have spread to all 
parts of each third-level IPM block and will 



have provided effective biocontrol of European 
red mites in such blocks, particularly in blocks 
of small trees. 

Acknowledgments 

We are grateful to the eight growers 
participating in this experiment and who made 
special effort to apply pesticide selectively to 
third-level IPM blocks: Bill Broderick, Dave 
Chandler, Dave Cheney, Dana Clark, Dave 
Shearer, Joe Sincuk, Tim Smith, and Mo 
Tougas. This work was supported by state/ 
federal IPM 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



13 



An Update on the 1991 Mcintosh 
Strain/Rootstock Trial 

Wesley R. Autio 

Department of Plant & Soil Sciences, University of Massachusetts 

As apple growers plan for future plantings, differences and those caused by rootstocks 

it is important to understand how different were additive. Secondarily, tree size and yield 

rootstocks and scions will perform. Much performance were studied. Because of some 

rootstock research in recent years has studied surprising results, the tree size and yield 

the interaction of scion and rootstock to allow performance from the Massachusetts half of 

for better choice of combinations for commer- the trial are reported here, 
cial orchards. 

In 1991, a pair of plantings was established Materials & Methods 
(one at the University of Massachusetts 

Horticultural Research Center in Belchertown In the summer of 1988, scions of Pioneer 

and one at the University of Maine Highmoor Mac (a Mcintosh seedling), Marshall Mcintosh, 

Farm in Monmouth) to study effects of a Chic-A-Dee Mcintosh, and Rogers Red Mcln- 

combination of Mcintosh strains plus one tosh were budded onto Mark, M. 7 EMLA, M. 27 

Mcintosh seedling and four rootstocks. The EMLA, and M.26 EMLA rootstocks at the 

original intent of this trial was to determine if University of Maine Highmoor Farm. Trees 

differences in ripening caused by strain were allowed to growth through the following 



Table 2. Yield efficiency and fruit weight in 1997of three strains of Mcintosh anc 


one Mcintosh 


seedhng on four rootstocks 


planted in 1991.' 












Yield efficiency (kg/cm^ trunk cross 










sectional area) 






Fruit 
weight 






Cumulative 




Rootstock/Cultivar 


1997 


(1993-97) 






(g) 


Mark 


0.77 b 


2.60 a 






157 a 


M.7 HMLA 


0.35 c 


1.19 c 






157 a 


M.27 EMLA 


1.04 a 


2.81 a 






146 a 


M.26 EMLA 


0.63 b 


2.21 b 






1 56 a 


Pioneer Mac 


0.74 a 


2.48 a 






145 c 


Marshall Mcintosh 


0.70 a 


1.84 b 






151 be 


Chic-A-Dee Mcintosh 


0.76 a 


2.40 a 






161 a 


Rogers Red Mcintosh 


0.59 a 


2.09 ab 






157 ab 


' Overall rootstock means 


within columns or 


overall cultivar 


means 


within 


columns are 


significantly different at odds of 19:1 if not foil 


owed by the same 


letter. 







14 Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Tabic 1. Trunk 


cross-sectional 


area and yield in 1997 of three strains of Mcintosh and one 


Mcintosh seedlir 


g on four rootstocks planted in 1991.' 






Pioneer 




Marshall Chic-A-Dee Rogers Red 




Rootstock 


Mac 




Mcintosh Mcintosh Mcintosh 


Average 








Trunk cross-sectional area (cm^) 




Mark 


30.4 c 




30.7 b 26.3 b 37.2 a 


31.2c 


M.7 EMLA 


72.8 a 




49.3 a 46.7 a 47.8 a 


54.2 a 


M.27 EMLA 


10,9 d 




9,8 c 7.2 c 7.9 b 


9.0 d 


M.26 EMLA 


41. 8b 




54.3 a 29.1b 37.0 a 


40.6 b 


Average 


39.0 a 




36.0 a 27.3 b 32.4 ab 
Yield per tree (kg, 1997) 




Mark 


23 b 




26 a 1 8 a 20 a 


22 ab 


M.7 EMLA 


24 ab 




14b 19a 18a 


19b 


M.27 EMLA 


10c 




9b 8b 9b 


9c 


M.26 EMLA 


32 a 




31a 20 a 12 ab 


24 a 


Average 


23 a 




20 ab 16 be 15 c 
Cumulative yield per tree (kg, 1993-97) 




Mark 


91 a 




76 a 59 a 84 a 


77 a 


M.7 EMLA 


93 a 




44 b 67 a 59 b 


66 b 


M.27 EMLA 


32 b 




20 c 23 b 24 c 


25 c 


M.26 EMLA 


106 a 




93 a 70 a 65 b 


83 a 


Average 


80 a 




58 b 55 b 58 b 




' Rootstock means within co 


umns or overall cultivar means are significantly different at odds of 


19:1 if not followed by the 


same 


letter. 





two seasons in the nursery. In April of 1991, 
seven replications of all combinations were 
planted at the University of Massachusetts 
Horticultural Research Center. Yield and tree 
size were assessed each year. 

Results & Discussion 

Overall tree size at the end of the seventh 
growing season followed expected patterns, 



with trees on M.7 EMLA the largest, and those 
on M.27 EMLA the smallest (Table 1). Further, 
Pioneer Mac and Marshall trees were 
significantly larger than Chic-A-Dee trees, and 
Rogers trees were intermediate. Interestingly, 
the relative differences among the four 
rootstocks were not similar across the 
cultivars. With Marshall Mcintosh, trees on 
M.7 EMLA were smaller than expected and 
similar to those on M.26 EMLA (Figure 1). 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



15 



D 

c 
O 

u= 

o 
a> 

(A 

o 
o 

C 
3 



100 
90 
80 
70 
60 
50 
40 
30 
20 
10 




Pioneer 



Marshall 



Mark 
M.7 EMLA 



M.27 EMLA 
M.26 EMLA 




Chic-A-Dee 



Rogers 



Figure 1. Trunk cross-sectional area in 1997 of three strains of 
Mcintosh and one Mcintosh seedHng on four rootstocks. Within 
cultivar, means without the same letter are significantly different 
at odds of 19:1. 






a- 



140 



120 



M 100 

0) 
01 



a 

4) 
'>. 

> 

J2 

3 

E 

3 

u 



80 



60 



40 



20 



"1 

Pioneer 




Marshall 



1 

Chic-A-Dee 



Rogers 



Figure 2. Cumulative yield per tree (1993-97) of three strains of 
Mcintosh and one Mcintosh seedling on four rootstocks. Within 
cultivar, means without the same letter are significantly different 
at odds of 19:1. 



16 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Cumulative yield generally was as ex- 
pected, with trees on M.26 EMLA producing 
the most fruit and those on M.27 EMLA the 
least. Pioneer Mac produced significantly more 
fruit than Chic-A-Dee or Rogers, and Marshall 
was intermediate; however, the relative 
differences among the rootstocks varied with 
cultivar. Cumulative yield of M.7 EMLA and 
M.26 EMLA were similar for Pioneer Mac, 
Chic-A-Dee, and Rogers, but Marshall/M.26 
EMLA yielded more than double Marshall/M.7 
EMLA (Figure 2). Rootstock effects on yield 
efficiency followed consistent trends among 
cultivars. Cumulatively, M.27 and Mark 
produced the most efficient trees, followed by 
M.26 EMLA, and M.7 EMLA produced the least 
efficient trees (Table 2). Cumulatively, Pioneer 
Mac and Chic-A-Dee were significantly more 



efficient than Marshall, with Rogers interme- 
diate (Table 2). 

Rootstock did not affect fruit weight in 
1997, but Chic-A-Dee resulted in significantly 
larger fruit than Marshall or Pioneer Mac 
(Table 2). 

Tliese results lead to an interesting 
question: Why does Marshall Mcintosh 
respond poorly to M.7 EMLA? One possibility 
is that M.7 EMLA is sensitive to a virus present 
in Marshall. Marshall is not a virus-fruit 
strain of Mcintosh. It may explain some of the 
variable results with Marshall Mcintosh in 
recent years, particularly reduced leaf quality, 
tree growth, and fruit size. If considering 
semi dwarf Mcintosh trees for future plantings, 
likely it is best to avoid the combination of 
Marshall and M.7 EMLA. 



•X* •X* *X* •X* *4^ 

0^ 0^ •<J^ r^ 0^ 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



17 



Comparison of Ladd Traps, Red Spheres, 
and Yellow Panels for Capturing 
Apple Maggot Flies in Commercial 
Apple Orchards 

Juan Rull and Ronald Prokopy 

Department of Entomology, University of Massachusetts 



In a recent study in commercial apple 
orchards, it was found that sticky red spheres 
baited with butyl hexanoate caught four times 
more apple maggot flies (AMF) than unbaited 
red spheres. However, not everyone agrees 
that baited red spheres are the best AMF trap. 
For example, studies carried out in the western 
U.S. seem to place sticky Ladd traps as being 
equal or superior to sticky red spheres. Ladd 
traps consist of a square yellow panel with a red 



sphere m the center. The yellow panel is 
believed to attract immature AMF whereas the 
red sphere is believed to attract mature AMF. 
Trap position is critical for effectiveness. We 
speculated that Ladd traps in poor position 
could have been more effective than red sphere 
traps in poor position in studies favoring Ladd 
traps as being superior. Finally, some of the 
studies on Ladd traps were not performed in 
commercial orchards, where incoming AMF 



Table 1. Number of apple 


maggot flies cau 


Lght by different traps 


in s 


L commercial orchard 


in Massachus 


etts from late July 


to early September, 


1997. 












Position in 




Early (wk) 




Late (w 


k) 




















Trap type 


tree 


1 


2 


3 


Total* 


4 


5 


6 


Total* 


Overall 

* 


Red sphere 


Optimal 


12 


19 


17 


48a 


12 


13 


22 


47a 


95a 


Red Sphere 


Poor 


4 


15 


14 


33a 


26 


13 


26 


65a 


98a 


Ladd 


Optimal 


8 


13 


14 


35a 


15 


18 


32 


65a 


100a 


Ladd 


Poor 





3 


9 


12b 


4 


6 


9 


19b 


31b 


Yellow Panel 


Optimal 


6 


3 


9 


18b 


4 


8 


2 


14b 


32b 


Yellow Panel 


Poor 


1 


2 


1 


4b 


2 


1 


3 


6b 


10b 


* Numbers followed by a different letter arc 


; significantly different at ( 


adds of 19:1. 



Fruit Notes, Volume 62 (Number 4), Fail, 1997 



populations are primarily composed of mature 
flies. To clarify conclusions on trap type 
effectiveness for AMF, we conducted the 
following experiment during the summer of 
1997. 

Materials & Methods 

In nine rows of apple trees in a commercial 
orchard in Massachusetts, the first six trees in 
each row (i.e. trees nearest adjacent woods) 
were selected for use. In the first row, the first 
tree contained a red sphere (8 cm in diameter) 
placed in optimal position (surrounded by as 
much foliage and fruit as possible at a distance 
of 3-6 inches), in the mid-portion of the tree 
canopy. The second tree contained a red sphere 
in poor position (few leaves and no fruit 
nearby). The third and fourth trees contained a 
Ladd trap (9 cm diameter red sphere centered 
on a 9x1 1-inch yellow panel) in optimal and 
poor position, respectively. The fifth and sixth 
trees contained a yellow panel (9x1 1-inch 
rectangle) in optimal and poor position, 
respectively. For every succeeding row, trap 
positions were rotated so that each trap type 
appeared in each within-row tree position three 
times. 

In every row, poor position was 

standardized for all traps, either low and out; 
high and out; or close to the trunk, high or low. 
A vial containing butyl hexanoate was placed 4 
to 6 inches away from every trap. Traps were 
serviced every week for six weeks, during 
which flies were removed and counted and 
sticky was replenished if needed. The 
experiment was conducted from late July to 
early September. 

Results 

Overall, red spheres in both optimal and 
poor positions and Ladd traps in optimal 
position caught similar numbers of flies and 
three times more flies than Ladd traps in poor 
position or yellow panels in either positions 
(Table 1). During the first three weeks, red 
spheres in optimal position caught numerically 
more flies than red spheres in poor position and 



Ladd traps in optimal position; the difference, 
however, was not significant. During the last 
three weeks, as fruit reached maturity, red 
spheres in optimal position caught numerically 
fewer flies than red spheres in poor position 
and Ladd traps in optimal position; again 
however, the difference was not significant. 
Across all six weeks Ladd traps in poor position 
and yellow panels in either position caught 
significantly fewer flies than red spheres in 
either position and Ladd traps in optimal 
position. 

Conclusions 

From late July to mid-August, red spheres 
in optimal position caught 35-40% more AMF 
than red spheres in poor position or Ladd traps 
in optimal position. The proximity of foliage 
and fruit to red spheres in optimal position 
probably facilitated more frequent opportunity 
for AMF to encounter such spheres. This could 
explain the numerical difference in capture 
between red spheres in optimal position versus 
red spheres in poor position. Yellow panels 
were comparatively unattractive irrespective 
of panel position. Ladd traps in poor position 
caught numbers of AMF similar to those on 
yellow panels. Apparently, in poor position, the 
red sphere component of a Ladd trap is not 
perceived as fruit by foraging AMF. 

By mid-August, the Paulared apples on the 
trapped trees had turned red and visually 
competed with red spheres in optimal position. 
At times, red sphere traps in optimal position 
were difficult for us to find in the trees. At that 
point, red spheres in poor position (placed 
farther away from competing fruit) and Ladd 
traps in optimal position began to capture more 
AMF than red spheres in optimal position. 
Ladd traps in optimal position might have 
enhanced the contrast of a red sphere against 
background by furnishing a yellow panel or 
background rather than red fruit. The effect 
could not be reproduced by Ladd traps in poor 
position. 

Efficiency of red spheres for trapping AMF 
seems to decrease when fruit reaches a size and 
color similar to the spheres. This factor 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



19 



deserves more attention. Trap positioning may Acknowledgments 

need to be adjusted toward harvest. We plan to 

conduct studies on the effect of fruit density on 

trap efficiency, an interfering factor that could 

affect management practices especially when 

early maturing cultivars of red apples are 

involved. 



We are grateful to Wayne Rice for allowing us 
to use his orchard. We thank Stephen Lavallee, 
Susan Nixson and Amy Wiebe for technical 
assistance. This work was funded by USDA 
CSRS NRI Grant 95-37313-1890. 



*X* *X* vL» *X> *\* 

•^ w^ #Y* *T* *T* 



20 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



Can We Predict Flyspeck Development? 



James C. Hall, Michael Frank, Arthur F. Tuttle, and Daniel R. Cooley 
Department of Microbiology, University of Massachusetts 



Flyspeck, caused by Schizothyrium pomi 
and sooty blotch, caused by a group of fungi 
including Peltaster fructicola, Leptodontium 
elatius, and Geastrumia polystigmatis are two 
common summer diseases of apple in New 
England. Recently, summer diseases have 
become more problematic due at least in part to 
the decreased use of fungicides such as 
mancozeb and captan, attributable to 
increased label restrictions, cost cutting, and 
the implementation of IPM programs 
(Rosenberger, Proc. New England Fruit 
Meetings \02:b\-bl, 1997). In July and August, 
growers are limited to a few fungicide 
applications, generally using captan with or 
without a benzimidazol. Growers could more 
effectively control sooty blotch and flyspeck 
within the confines of an IPM program if they 
were able to time their sprays better so as to 
correspond to infection and the eventual 
appearance of these diseases. Specifically, a 
more economical and effective application of 
fungicides could be accomplished if growers 
were able to predict the appearance of flyspeck 
disease and sooty blotch. It would then be 



possible to replace a preventative spray 
program with one or more eradicant sprays 
timed to thwart the appearance of these 
diseases. 

In North Carolina, Brown and Sutton 
{Plant Disease 79:1165-1168) have developed a 
model for the prediction of sooty blotch and 
flyspeck disease symptoms on apples. The 
model is based on leaf wetness data collected at 
three different sites in North Carolina from 
1987 through 1994, coupled with known 
biological information about the fungi involved. 
From these data, the researchers concluded 
that the best estimate of flyspeck and sooty 
blotch symptom occurrence was based on the 
cumulative hours of leaf wetness during 
periods of at least four hours duration, 
beginning from the first rainfall at least 10 
days after petal fall. Brown and Sutton chose to 
include periods of at least four hours because 
they had previously demonstrated that the 
pathogens required about four to five hours of 
constant wetting in order to germinate (Plant 
Disease 77:451-455). Under these conditions, 
the researchers found that flyspeck and sooty 



Table 1 . 


Leaf 


wetness accumulation from 10 days after petal fall until the first 


symptoms of 


sooty blotch or 


flyspeck. Table derived from Brown and Sutton (Plant Disease 79: 1 165-1 168). 










Symptoms observed Accumulated wetting | 


Year 




Petal fall date 


Beginning date 




(hrs) 


1987 




27-Apr 


5-May 


15-Jun 


265 


1988 




28-Apr 


1 1-May 


26-Jul 


304 


1989 




26-Apr 


9-May 


23-Jun 


276 


1990 




25- Apr 


6-May 


16-Jul 


289 


1991 




25-Apr 


6-May 


4-Jun 


267 


1992 




1-May 


13-May 


15-Jun 


310 


1993 




7-May 


17-May 


6-Jul 


209 


1994 




29-Apr 


14-May 


21-Jun 


242 


1 



Fruit Notes, Volume 62 (Number 4), Fall, 1997 



21 



blotch symptoms occurred after an average of 
270 hours of accumulated leaf wetting. They 
believe this that information is useful for 
timing eradicant (benzimidazole) fungicide 
spraying. An admitted limitation of this model 
is the questionable relevance it has for regions 
outside the southeastern United States. Sooty 
blotch and flyspeck disease pressure are 
extremely high in the Southeast. Weather 
there is particularly favorable for these 
diseases. Therefore, the model might fail to 
predict accurately the onset of sooty blotch and 
flyspeck symptoms for several reasons: 1) 
summer temperatures and relative humidities 
in New England are usually lower than in 
North Carolina; 2) the precision and accuracy 
of different leaf wetness sensors can vary 
considerably; and 3) infection of apple trees 
with the fungi causing flyspeck occurs about 
one month later in New England than in North 
Carolina. However, the existance of an 
empirical model predicting flyspeck and sooty 
blotch diseases anywhere raises the possibility 
of constructing such a model in New England. 
While noting the limitations and possible 
sources of error, Brown and Sutton's model is 
still a good starting place. Additionally, one 
only needs hourly leaf wetness data available 



over the course of at least one year in order to 
use their model. These leaf wetness data are 
readily available from records taken from 
hygrothermographs or Campbell computerized 
weather stations located in several Massachu- 
setts orchards. Thus, beginning with leaf 
wetness data collected from nine different 
orchards in 1995 and 1996, we tested Brown 
and Sutton's model for the prediction of 
flyspeck and sooty blotch. 

Table 1 from Brown and Sutton's article 
shows wetness data collected from 1987 
through 1994. Symptom occurrence ranged 
from late June through early July, with a mean 
wetness duration of 270 hours between the 
beginning date and symptom occurrence. Note 
that Brown and Sutton began counting wetness 
hours starting from the first significant 
wetness period at least 10 days after petal fall. 
Thus, their starting date ranged from early to 
mid May. 

In contrast, Table 2 shows data collected 
from Massachusetts orchards during 1995 and 
1996. Using Brown and Sutton's criteria, the 
mean leaf wetness accumulation of four hours 
or greater from 10 days after petal fall to 
symptom occurrence was 366 hours (standard 
deviation = 120 hours; the larger the standard 



Table 2. 


Leaf wetness accumulation from 10 days 


after petal 


fall to the first symptoms 


of flyspeck in 


Massachusetts. 
















Petal fall 


Beginning 


Symptoms 




Accumulated 


Year 


Site 


date 


date 


observed 


Data source 


wetting (hrs) 


1995 


Broderick 


25-May 


4-Jun 


8-Aug 


Hygrothermograph 


258 


1995 


HRC 


24-May 


3-Jun 


7-Aug 


Hygrothermograph 


348 


1995 


Clark 


28-May 


7-Jun 


17-Aug 


Hygrothermograph 


264 


1996 


HRC 


26-May 


5-Jun 


24-Jul 


Hygrothermograph 


236 


1996 


Lincoln 


27-May 


6-Jun 


29-Jul 


Hygrothermograph 


295 


1996 


Tuitle 


26-May 


5-Jun 


31-Jul 


Hygrothermograph 


331 


1996 


Simeone 


26-May 


6-Jun 


30-Jul 


Campbell 


484 


1996 


Sholan 


26-May 


5-Jun 


14-Aug 


Campbell 


586 


1996 


HRC 


26-May 


5-Jun 


24-Jul 


Campbell 


275 


1996 


Rice 


23-May 


5-Jun 


2-Aug 


Campbell 


422 


1996 


S. Deerfield 


26-May 


5-Jun 


1-Aug 


Campbell 


522 


1 



22 



Fruit Notes, Volume 62 (Number 4). Fall, 1997 



deviation the more variable the sample was). 
The mean for the 1995-1996 hygrothermograph 
data alone was much closer to Brown and 
Sutton, however, with a mean of 289 hours 
(standard deviation = 44 hours). Thus, using 
data most favorable to the Brown and Sutton 
model, approximately 19 more hours of wetting 
occurred in Massachusetts, on average, than in 
North Carolina before flyspeck and sooty blotch 
symptoms occur. These measurements 

support the idea that the Brown and Sutton 
model may indeed be useful for disease 
prediction in Massachusetts. The Campbell 
data, however, do not provide as much 
support. In addition, note that the significant 
events of petal fall, beginning of wetness 
measurement, and symptom occurrence 
happened later in Massachusetts than in North 
Carolina. 

Judging from the differences between the 
two data sets as well as the previously noted 
regional differences between New England and 
the Southeast, it is reasonable to conclude that 
other factors besides leaf wetness are 
responsible for the onset of flyspeck and sooty 
blotch in New England. This certainly could 
account for the rather large variability in the 



New England data. A regression analysis of 
other weather measurements like temperature 
and relative humidity with disease onset may 
suggest some additional factors. This will be 
the focus of future research. It is also 
important to note that there is a disparity 
between the Campbell weather station wetness 
data and the hygrothermograph wetness data, 
and it cannot be ruled out that the measuring 
instruments themselves may be a source of 
error. There is no easy solution to this problem, 
and it may be that different empirical wetness- 
hour estimations may have to be made for use 
with different wetness sensors, or an easily 
accessible, standard weather station will have 
to be used. 

In conclusion, it is believed that an 
empirical model predicting flyspeck disease 
and sooty blotch of apple based upon the Brown 
and Sutton model should be created for use by 
New England apple growers. Such a model 
would be useful to Massachusetts growers for 
timing eradicant fungicide spraying for these 
diseases in a more timely and efficient manner, 
and may also provide researchers with further 
insight into the ecology of the pathogens 
involved. 



•^ vL» vL» vL« vL* 
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Fruit Notes, Volume 62 (Number 4), Fall, 1997 



23 




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 
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SERIAL SECTION 

UNIV OF MASSACHUSETTS LIBRARY 

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Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

UMass Extension, U. S. Department of Agriculture, and Massachusetts Count ies Coope rating. 

BIOLOGICAL 



Editors: Wesley R. Autio and William J. Bramlage 



MAY 2 9 1998 
SCIENCES LIBRARV 




O 



CO 
CO 



-c CD 
iNJ JO 

-^ > 

-< 



Volume 63, Number 1 
WINTER ISSUE, 1998 

Table of Contents 



Rootstock and Scion Interact 
to Affect Apple Tree Performance 

Plum Curculio Responses to Host Fruit and Conspecific Odors 

Evaluation of Unbaited Pyramid Traps for 
Monitoring Plum Curculio in Commercial Apple Orchards 

Eyes on Plum Curculio: Watching Them Behave 

Toward Traps Alternative to Black Pyramids 
for Capturing Plum Curculios 



Fruit Notes 



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Fruit Notes 

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All chemical uses suggested in this publication are contingent upon continued registration. 
These chemicals should be used in accordance with federal and stale laws and regulations. 
Growers are urged to be lamiliar with all current stale regulations. Where trade names are used 
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University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied, 
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INJURY OR PROPERTY DAMAGE. 



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UMass Extension offers equal opportunity in profirams and employment. 



Rootstock and Scion Interact to Affect 
Apple Tree Performance 

Wesley R. Autio, J. LaMar Anderson, John A. Barden, 
Gerald R. Brown, Paul A. Domoto, David C. Ferree, Alvan Gaus, 
Richard A. Hayden, Frank Morrison, Charles A. MuUins, 
Curt R. Rom, James R. Schupp, and Loren D. Tukey 
NC-140 1990 CultivarlRootstock Trial Cooperators 



For about 20 years, the NC-140 Regional 
Research Committee has been stud3dng the 
effects of rootstock on the performance of 
various tree-fruit crops. The first and second 
cooperative plantings of NC-140 included 
Delicious apple on a variety of rootstocks from 
subdwarf to vigorous. Much useful information 
was generated from these trials, particularly 
because of the rigorous, systematic evaluation 
of performance and the large number of sites 
and conditions that trees were exposed to. A 
total of 25 to 30 sites were included, ranging 
from Mexico and the southern United States to 
several Canadian provinces. 

Delicious was the cultivar of choice for 
these early plantings, because it was important 
for all growing regions; however, little 
information was generated on how rootstocks 
may affect different cultivars. In fact, no large- 
scale trial had looked at the interaction of 
rootstock and scion in a systematic way. 
Therefore, planning began in 1987 to establish 
such a trial. 

Trees for the 1990 NC-140 Cultivar/ 
Rootstock Trial were propagated by Stark Bro's 
Nurseries during the winter of 1989 and were 
grown in Selma, CA during the 1989 growing 
season. Trees were dug in the fall and shipped 
to cooperative sites (see tables for a list of 
locations) in the late winter and early spring of 
1990. Each site included six replications of four 
cultivars (Smoothee Golden Delicious, Nicobel 
Jonagold, Empire, and Law Rome) on five 
rootstocks (M.9 EMLA, B.9, Mark, 0.3, and 
M.26 EMLA). The four cultivars were chosen 



with different growth habits, ranging from the 
basitonic (spur-type) Empire to the acrotonic 
(tip-bearing) Rome. The rootstocks were the 
most promising from the first two NC-140 
cooperative trials. 

Trees were individually staked and man- 
aged as slender spindles with a standard 
protocol. Pest management, irrigation, and 
fertilization were per local recommendations. 
Yield and tree size were measured annually. 
Data reported here are through the seventh 
growing season (1996). 

Using trunk cross-sectional area as a 
measure of tree size (Table 1), it is clear that 
rootstock affected trees size differently, 
depending on cultivar. M.26 EMLA, however, 
resulted in the largest tree, regardless of 
cultivar. Golden Delicious and Empire trees on 
M.9 EMLA were significantly smaller than 
those on 0.3, but Rome trees on the two 
rootstock were similar in size, and Jonagold 
trees on M.9 EMLA were signficantly larger 
than those on 0.3. Jonagold, Empire, and 
Rome trees on B.9 were similar in size to those 
on Mark, however. Golden Delicious trees on 
B.9 were larger than comparable trees on 
Mark. The cultivars also differed overall. 
Specifically, Jonagold trees were the largest 
and Empire trees were the smallest. Site 
differences were very dramatic. Trees in 
Wichata, Kansas were the largest, and those in 
Maine were the smallest, less than 1/3 of the 
size of the Kansas trees. Massachusetts trees 
were not significantly larger than those in 
Maine. 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



Table 1 Trunk cross-sectional 


area at the end c 


f the 1996 growing 


season. 






Trunk cross-sectionai 


area ( 


cm-^) 




Golden 










Rootstock 


Delicious 


Jonagold 


Empire 




Rome Average 


M.9EMLA 


49.7 c 


59.8 b 


45.5 c 




54.7 b 52.8 b 


B.9 


35.3 d 


34.7 d 


32.1 d 




32.4 c 33.6 c 


Mark 


30.0 e 


31.6 d 


28.3 d 




30.1c 30.0 d 


0.3 


57.4 b 


51.7 c 


51.2 b 




55.6 b 54.0 b 


M.26 EMLA 


67.8 a 


74.9 a 


64.1 a 




64.8 a 68.0 a 


Average 


48.5 ab 


50.6 a 


44.3 c 




47.4 b 






Trunk cross- 












sectional 








Site 




area (cm^) 








Arkansas 




42.2 ef 








Colorado 




34.1 g 








Iowa 




42.0 ef 








Indiana 




45.5 def 








Kansas-Manhattan 


68.5 b 








Kansas-Wichita 




89.3 a 








Kentucky 




49.6 cd 








Massachusetts 




30.8 gh 








Maine 




28.1 h 








Ohio 




46.5 de 








Pennsylvania 




30.9 gh 








Tennessee 




39.7 f 








Utah 




53.4 c 








Virginia 




66.9 b 








Rootstock means 


within columns, average rootstock means, average cultivar means, or 


average site means are significantly different at 


odds of 19:1 


if not followed by the same | 


letter. 













The effects of rootstock on cumulative yield 
per tree also varied with cultivar (Table 2). The 
general trends were similar to those with tree 
size, with trees on 0.3 and M.26 EMLA yielding 
the most, those on B.9 and Mark yielding the 
least, and trees on M.9 EMLA yielding 
intermediately. Over all rootsotcks, Rome 
trees produced the highest yield, and Empire 
trees produced the lowest. Regarding the 
effects of site, trees in Virginia and Ohio 



produced the highest yields, and those in 
Arkansas produced the lowest. 

More important than yield per tree, the 
effects of rootstock on cumulative yield 
efficiency (relating yield to tree size) varied 
with cultivar (Table 3). The most efficient 
Golden Delicious, Jonagold, and Empire trees 
were on B.9 and Mark, and the least efficient 
were on M.26 EMLA. Trees on M.9 EMLA and 
0.3 were intermediate. Rome trees on B.9 were 



Fruit Notes, VoUimc 63 (Number 1), Winter, 1998 



Table 2. Cumulative yield per tree (1992-96) at the end of the 1996 growing season. 



Rootstock 



Golden 
Delicious 



M.9EMLA 

B.9 

Mark 

0.3 

M.26 EMLA 

Average 



Site 



74 b 
69 be 
61 c 
94 a 
89 a 

78 b 



Arkansas 

Colorado 

Iowa 

Indiana 

Kansas-Manhattan 

Kansas-Wichita 

Kentucky 

Massachusetts 

Maine 

Ohio 

Pennsylvania 

Tennessee 

Utah 

Virginia 



Cumulative yield (kg/tree, 1992-96) 



Jonagold 



Empire 



74 b 
60 c 
54 c 
81 ab 
85 a 

71c 



71 b 
53 c 
43 d 
83 a 
77 ab 

66 d 



Cumulative 

yield (kg/tree 

1992-96) 



21 1 

32 h 

33 h 

48 fg 
139 b 
126 c 
80 d 
86 d 
54 f 

149 a 

49 gh 
35 h 
65 e 

150 a 



Rome 



96 a 
79 b 
62 c 
102 a 
95 a 

87 a 



Average 



80 b 
65 c 
55 d 
90 a 

87 a 



Rootstock means within columns, average rootstock means, average cultivar means, or 
average site means are significantly different at odds of 19:1 if not followed by the same 
letter. 



the most efficient, those on M.26 EMLA were 
the least efficient, and those on Mark, M.9 
EMLA, and 0.3 were intermediate. Rome 
trees, overall, were the most yield efficient, and 
Jonagold trees were the least efficient. Ohio 
and Massachusetts produced the most yield- 
efficient trees, and Arkansas produced the 
least efficient. 

This study, which will continue through the 
tenth growing season, has demonstrated 



variation in the effects of rootstock with 
different cultivars. To date, however, the 
importance of the variation is minimal. Tlie 
reduced size of Jonagold trees on 0.3 is an 
important deviation ft-om the response with 
other cultivars. The tree is smaller than 
expected, but it is as yield efficient as it should 
be. Unless this observation is a reflection of 
some level of incompatibility between scion and 
rootstock, the only change that a grower needs 



Fruit Notes, Volume 63 (Number 1), Wmter, 199H 



Table 3. Cumulative yield efficiency (1992-96) at the end of the 1996 growing season. 

Cumulative yield efficiency (kg/cm^ trunk cross-sectional area, 1992-96) 



Rootstock 



Golden 
Delicious Jonagold Empire 



Ror 



Average 



M.9 EMLA 


1.61 b 


1.37 be 1.61b 


1.74 b 


1.59 c 


B.9 


1.97 a 


1.91a 1.91a 


2.37 a 


2.05 a 


Mark 


2.09 a 


1.80 a 1.88 a 


1.95 b 


1.93 b 


0.3 


1.71b 


1.48 b 1.72 ab 


1.83 b 


1.69 c 


M.26 EMLA 


1.35 c 


1.19 c 1.16 c 


1.51c 


1.30 d 


Average 


1.75 b 


1.55 c 1.65 be 


1.89 a 








Cumulative yield 










efficiency (kg/cm^ 






Site 




1992-96) 







Arkansas 










0.51 h 


Colorado 










1.01 fg 


Iowa 










0.90 gh 


Indiana 










1.13 ef 


Kansas-Manhattan 










2.34 c 


Kansas-Wichita 










1.78 d 


Kentucky 










1.85 d 


Massachusetts 










2.94 b 


Maine 










1.96 d 


Ohio 










3.48 a 


Pennsylvania 










1.32 e 


Tennessee 










1.04 fg 


Utah 










1.32 e 


Virginia 










2.37 c 


Rootstock means withi 


n columns, 


average 


rootstock means, average cultivar means, or 


average site means are 


sign 


ificantly di 


fferent at odds of 19:1 if not followed by the same | 


letter. 













to make to use this combination is adjustment ated with Mark. In this study, rootstock did not 



of planting distances. 

Tlie rootstock that stands out in this trial is 
B.9. It performed similarly well with all scions. 
Yield efficiency was as high or higher than 
Mark, without many of the problems associ- 



affect fruit size, but in other trials, B.9 has 
resulted in larger-than-average fruit. It 
certainly is a rootstock worthy of significant 
grower trial, and it is available commercially in 
significant quantities. 



•JL» vT^ •X* •^ •J^ 

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Fruit Notes, Volume 6.^ (Number 1), Wimcr, 1998 



Plum Curculio Responses to Host Fruit 
and Conspecific Odors 

Tracy Leskey, Amy Wiebe, Susan Nixson, and Ronald Prokopy 
Department of Entomology, University of Massachusetts 



Many species of weevils are attracted to host 
plant odors and use them in host finding. Fur- 
ther, many species of weevils produce aggrega- 
tion and/or sex pheromones. Plum curculios 
(PCs) have been shown to be attracted to host 
fruit odors in the laboratory over short distances 
and in the field at distances up to 3 yards. Fur- 
ther, a male-produced aggregation pheromone, 
grandisoic acid, was recently identified in PCs 
by Eller and Bartelt of Illinois. 

At present, a reliable monitoring system for 
detecting adult PC entry into orchards from 
overwintering sites does not exist. However, if 
attractive odors such as those from host fruit 
and/or pheromones were employed in conjunc- 
tion with a trap that was also visually attrac- 
tive to adult PCs, then a reliable monitoring 
device could be created as has been done for 
other species of weevils. 

In the 1996 and 1997 Winter issues of Fruit 
Notes, we reported on results of laboratory 
Petri-dish bioassays that addressed responses 
of adult PCs to odors emitted from Mcintosh 
apple trees. Here, we present results from bio- 
assays conducted in large Plexiglas arenas de- 
signed to assess PC attraction not only to fruit 
odors but also to odors emitted by other PCs. 



Materials and Methods 

Large clear Plexiglas arenas with dimen- 
sions of 24x24x12 inches with Plexiglas lids 
were used as still-air arenas for the following 
experiments. Materials to be tested as emit- 
ting potentially attractive odors were placed in 
small cotton bags hung in the upper corners (one 
per corner) of each box. Originally, we tried 
testing PCs with cotton bags placed in lower 
corners of arenas, but found that because of the 
natural tendency of PCs to crawl upwards, 
hanging the bags in upper corners was a more 
effective means of testing PCs. 

Either ten male or ten female PCs starved 
for 24 hours and chilled 30 minutes prior to test- 
ing were released into the center of a box at the 
beginning of darkness. Numbers of PCs that 
crawled to within one-half inch of an odor source 
held within a cotton bag were recorded after 1 
hour. Each experiment was repeated three 
more times, each time rotating the position of 
cotton bags containing odor sources. 

Treatments tested as potentially emitting 
attractive odors included five freshly picked 
wild plums, five wild plums plus five male or 
female PCs, five male or female PCs alone, five 



Table 1. Numbers of male PCs moving to within 1/2 inch 
treatment after 1 hour. Experiment 1.* 


or onto cloth bags of each 


Arena 




Treatments 






One 


Five males 
O.Ob 


Five males + five plums 
3.3 a 


Five plums 
3.0 a 


Control 
O.Ob 


Two 


Five females 
0.0 c 


Five females + five plums 
6.0 a 


Five plums 
1.0 b 


Con trol 
0.0 c 


* Means within rows not followed by the same letter are significantly different at 
odds of 19:1. 



Fruit Notes, Volume 6,3 (Number 1), Winter, 1998 



Table 2. Numbers of male PCs moving to within 1/2 inch or onto 
treatment after 1 hour. Experiment 2.* 


cloth bags of each 


Arena 


Treatments 






One 


Fiue punctured plums Five plums 
3.5 a 1.8 ab 


Control 
O.Ob 


Control 
O.Ob 


Two 


Five females + five plums Five males + five plums 
3.8 a 1.0 b 


Control 
O.Ob 


Control 
O.Ob 


* Means within rows not followed by the same letter are significantly different at 
odds of 19:1. 



wild plums alone, and five punctured plums. 
Punctured plums were used to simulate plums 
that had been fed upon by PCs because we 
wanted to learn if plums that had been punc- 
tured released odors that may be attractive to 
PCs. Each plum was punctured twice, one punc- 
ture made one hour before and one puncture 
made immediately before an experiment. An 
empty cotton bag served as the control in each 
experiment. 

Results presented reflect the mean number 
of PCs captured for each treatment over the four 
replications. 

Results 

Male Responses. In experiment 1 (Table 
1), we used two arenas to test male response to 
the following treatments. In arena one, treat- 
ments included males, males plus wild plums, 
and wild plums placed in a small cotton bag, 
with an empty cotton bag serving as the con- 
trol. Here, males responded in significantly 
greater numbers to cotton bags containing 
plums alone or males plus plums compared to 



males alone or the empty bag. Treatments 
tested in arena two included females, females 
plus plums, plums, and a control. In this case, 
males were attracted to females plus plums in 
significantly greater numbers than to any other 
treatment. 

In experiment 2 (Table 2), in arena 1 we then 
evaluated male responses to punctured plums 
compared to plums without punctures with two 
empty cotton bags serving as controls. Here, 
we wanted to learn if males were responding to 
odor emitted by punctures made in plums by 
feeding PCs. We saw no difference in response 
of males to punctured plums compared to plums 
not punctured, although there was a numeri- 
cally greater response to the former. In arena 
two, we compared male responses to females 
plus plums, males plus plums and to two empty 
bags serving once again as controls. Signifi- 
cantly more males responded to females plus 
plums than to any other treatment, indicating 
that males may be responding to a female-pro- 
duced odor. 

Female Responses. In experiment 3 
(Table 3), we repeated treatments for female 



Table 3. Numbers of female PCs moving to within 1/2 inch or onto cloth bags of each 
treatment after 1 hour. Experiment 3.* 



Arena 



Treatments 



One 



Five males Five males + five plums Five plums 
OOb 2.8 a 1.3 ab 



Con trol 
O.Ob 



Two 



Five females Five females + five plums Five plums Control 

O.Ob 1.0 ab 2.8 a O.Ob 



* Means within rows not followed by the same letter are significantly diffcn>nt at 
odds of 19:1. 



Fruit Notes, Volume 6.^ (Numhcr 1), Winter, 1998 



Table 4 


Numbers of female PCs moving to within 1/2 inch or or 


to cloth b 


ags 


of each 


treatment after 1 hour. Experimen 


t4.* 








Arena 




Treatments 










Five punctured plums 


Five plums 


Control 




Control 


One 


2.3 ab 


2.5 a 


O.Ob 




O.Ob 




Five females + five plums 


Five males + five plums 


Control 




Control 


Two 


1.5 a 


2.3 a 


0.0 a 




0.0 a 



* Means within rows not followed by the same letter are significantly different at 
odds of 19:1. 



responders that we tested with male respond- 
ers in experiment 1. In arena one, female re- 
sponders were attracted to males plus plums 
in significantly greater numbers than to males 
alone or the control bag, with intermediate at- 
traction to plums alone. In arena two, signifi- 
cantly more females were attracted to plums 
alone than to controls, with intermediate at- 
traction to females plus plums. 

In experiment 4 (Table 4), we repeated the 
same treatments with female responders that 
we had tested with male responders in experi- 
ment 2. In arena one, females responded in 
nearly equal numbers to punctured plums and 
plums that had not been punctured. In arena 
two, numerically more females were attracted 
to males plus plums compared to females plus 
plums or to control. 

Conclusions 



Both sexes were attracted to odors emitted by 
freshly picked wild plums. Perhaps the most 
important result from these experiments is an 
indication of the existence of a female-produced 
sex pheromone, as evidenced by the strong at- 
traction of male PCs to the treatment that in- 
cluded females plus wild plums. Further, this 
putative female-produced pheromone may have 
been synergized or enhanced in attractivity to 
males by the presence of wild plum odor. Al- 
though we cannot rule out the possibility of 
sounds made by PCs as influencing these re- 
sults, we could smell a unique odor in arenas 
that included treatments containing females 
plus plums. We plan to use this bioassay sys- 
tem extensively in 1998 to confirm these pre- 
liminary findings and in tests aimed at identi- 
fying the chemical nature of these attractive 
compounds. 



We conclude that the Plexiglas arena bioas- 
say system is an effective way to test PC at- 
traction to host fruit odors as well as odors 
emitted by other PCs at distances of approxi- 
mately 16 inches under still-air conditions. 



Acknowledgments 

This work was supported by Hatch funds 
and by the New England Tree Fruit Growers 
Research Committee. 



vty^ vT>» vl>* vT>» vj>» 
•^ ^j^ •^ •^ r^ 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



Evaluation of Unbaited PyramidTraps for 
Monitoring Plum Curculio in Commercial 
Apple Orchards 

Ronald Prokopy, Michael Marsello, Tracy Leskey, and Starker Wright 
Department of Entomology, University of Massachusetts 



In the 1997 Winter issue of Fruit Notes, we 
reported on a 1996 study evaluating unbaited 
black pyramid traps as devices for capturing 
plum curculio adults and predicting need and 
timing of insecticide sprays against plum 
curculio based on trap captures. That study, 
conducted in a small commercial apple orchard 
in Conway, showed that even though black p5Ta- 
mid traps in optimum positions (next to apple 
tree trunks) captured reasonable numbers of 
plum curculios, there was no correlation be- 
tween periods of substantial capture and peri- 
ods of substantial damage by curculios to fruit. 
In other words, trap captures were poor predic- 
tors of when insecticides should be applied 
against curculio in that orchard in 1996. Black 
pyramid traps, intended to mimic tree trunks, 
are currently receiving much attention as po- 
tential monitoring devices for plum curculio in 
peach orchards in the South. 

Here, we report on a study in which black 
pyramid traps were evaluated at three positions 
in eight large commercial orchards in Massa- 
chusetts in 1997. 

Materials and Methods 

Pyramid traps were the same as used in 
1996 and were a modification of traps designed 
for monitoring pecan weevils in the South. 
Three traps were placed in each of six blocks of 
apple trees in each of eight commercial orchards. 
All blocks contained 49 trees (seven rows of 
seven trees each) of mixed cultivars of fruit- 
bearing age. Of the six blocks per orchard, there 
were two blocks each of trees on M.9, M.26, and 
M.7 rootstock, giving rise to what we term here 



as small, medium, and large trees, respectively. 
For each block, one trap was placed within 30 
cm of the tree trunk (termed trunk trap) of a 
perimeter tree, one mid-way between the 
canopy of a perimeter tree and the first inte- 
rior tree (termed inter-tree trap), and one at the 
margin of the nearest woods (termed border 
trap). The ground beneath and between orchard 
trees was either free of b vegetation or vegeta- 
tion was mowed to prevent obscuring of traps. 
Traps were deployed during bloom and were 
examined for captured plum curculio adults ev- 
ery 3-4 days thereafter for 4-5 weeks. At each 
trap examination, beginning at petal fall, 15 
fruit per tree of each of the seven perimeter trees 
were examined for presence of plum curculio 
oviposition scars (total of 105 fruit per block per 
sampling date). Scarred fruit were allowed to 
remain on the tree. All blocks received either 
two or three grower-applied sprays of Guthion 
or Imidan, beginning at petal fall and 8-11 days 
later(second spray), as well as 16-20 days (third 
spray) thereafter. Growers applied sprays ac- 
cording to their own estimation of need, with- 
out access to our data for making application 
decisions. To protect against insecticide, a plas- 
tic bag was used to envelope each trap com- 
pletely just before spraying and was removed 
immediately thereafter. This was done because 
in a preliminary test, only about 40% as many 
curculios (0.8 vs. 1.9 per trap, a significant dif- 
ference) were captured by traps sprayed with 
Imidan as by unsprayed traps. 

Results 

We combined data for the two blocks of simi- 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



Table 1. 


Numbers of overwintering plum 


curculio adults captured 


on unbaited pyramid 


traps at tree-trunk, 


inter-tree 


or orchard-border positions and | 


aercent of fruit showing ovipositional 


injury by plum curculio across | 


sampling 


dates before, between, or after insecticide spray applications against 


pl 


um curcul 


10 in blocks of small, 


medium-size, or large apple trees and across 


eight commercial orchards studied 


in 


Massachusetts in 


1997. 










Adu 


Its 


captured 


aer 


Injured 






No. 


Sampling 


saff 


pling date 




_ fruit per 






orchard 


dates per 


Trunk 


Inter-tree 


Border 


sampling 


Tree size 


Sampling dates 


blocks 


block 


traps 




traps 


traps 


date (%) 


Small 


Before first spray 


16 


1.1 


0.22 




0.22 


0.22 


0.00 




Between first and second spray 


16 


2.5 


0.00 




0.05 


0.05 


0.35 




Between second and third spray 


6 


2.7 


0.00 




0.00 


0.00 


0.36 




After final spray 


16 


4.4 


0.00 




0.00 


0.00 


0.45 


Medium 


Before first spray 


16 


1.1 


0.00 




0.11 


0.11 


0.00 




Between first and second spray 


16 


2.5 


0.05 




0.00 


0.05 


0.33 




Between second and third spray 


6 


2.7 


0.00 




0.00 


0.00 


0.36 




After final spray 


16 


4.4 


0.00 




0.00 


0.00 


0.42 


Large 


Before first spray 


16 


1.1 


0.22 




0.00 


0.11 


0.00 




Between first and second spray 


16 


2.5 


0.10 




0.00 


0.05 


0.31 




Between second and third spray 


6 


2.7 


0.00 




0.00 


0.00 


0.48 




After final spray 


16 


4.4 


0.03 




0.00 


0.00 


0.90 


1 



lar tree size per orchard and segregated data 
according to sampling dates before, between, 
and after insecticide applications. The data 
(Table 1) show that no fruit injury was detected 
prior to the first insecticide application even 
though some curculio captures by traps in each 
position had occurred. For none of the trap po- 
sitions in any block type (i.e. tree-size type) was 
there a significant positive relationship between 
mean number of captured adults per block and 
mean number of sampled fi-uit injured per block. 
This was true for sampling data between the 
first and second insecticide application, between 
the second and third insecticide application, and 
following the last insecticide application. In 
every block type, mean ft-uit injury increased 
between the first and second, between the sec- 
ond and third, and after the third insecticide 
application. Conversely, in most cases, mean 
trap captures either successively decreased 
fi-om levels that were reached prior to any in- 
secticide treatment or were nil throughout. 

The greatest fruit injury in any of the 48 
blocks was in a block of large trees in Orchard 
D (a mean of 2.5% fruit injured). Not a single 
plum curculio was captured by any trap in this 
block. Conversely, in the two blocks receiving 
the greatest trap captures (small trees in Or- 



chard D and large trees in Orchard F), there 
were means of only 0.24 and 0.19% injured fi*uit, 
respectively. Most blocks received injury greater 
than this. 

Conclusions 

Data from this study in eight large commer- 
cial apple orchards in 1997 are in agreement 
with data ft-om our 1996 study in a single small 
orchard and do not support the use of captures 
of plum curculio adults by unbaited black pyra- 
mid traps as accurate predictors of the need to 
apply insecticide against curculio. This conclu- 
sion holds irrespective of the position at which 
unbaited pyramid traps were placed in an or- 
chard. For the future, we need either a differ- 
ent type of trap or a powerful attractive odor to 
enhance the value of black pyramid traps. In 
succeeding articles in this issue, we describe 
progress toward developing alternative types 
of traps and attractive odors to incorporate into 
traps. 



Acknowledgments 

This work was supported by grants fi-om the 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



USDA Northeast Regional IPM Competitive ers that participated in this study: Bill 

Grants Program, State /FederallPM funds, and Broderick, Dana Clark, Dave Chandler, Dave 

the New England Tree Fruit Growers Research Cheney, Dave Shearer, Joe Sincuk, Tim Smith 

Committee. We are grateful to the eight grow- and Mo Tougas. 



*sL* vL* vj/* *sl>* *sL* 

•^ #^ 0^ *J^ #^ 



10 Fruit Notes, Volume 63 (Number 1), Winter, 1998 



Eyes On Plum Curculios: 
Watching Them Behave 

Ronald Prokopy and Catherine Wirth 

Department of Entomology^ University of Massachusetts 



Shortcomings of black pyramid traps for 
monitoring plum curculios described in the pre- 
ceding article have stimulated us to take a closer 
look at the behavior of individual curculios in 
hopes of discovering why black pjrramid traps 
perform less and less satisfactorily as the 
curculio season progresses. In the 1997 Winter 
issue of Fruit Notes, we described some pre- 
liminary studies that led us to postulate that 
perhaps curculios bypass pjramid traps under 
moderate and high temperature conditions, fly- 
ing directly into tree canopies rather than crawl- 
ing or flying onto tree trunks or trunk-mimick- 
ing pyramid traps. Here, we describe two stud- 
ies conducted in 1997 in which we made exten- 
sive direct observation of movements of plum 
curculios toward host trees and p5rramid traps 
under conditions as natural as possible for typi- 
cal curculio behavior, while still permitting ef- 
fective observation. 

Materials and Methods 

Curculios to be observed were tapped from 
branches of unmanaged apple trees onto a 
40x40-inch white bedsheet (first study) or a 
16xl6-inch white bedsheet (second study) held 
taut by staples driven into a wooden frame be- 
neath. Apple foliage was scattered across about 
15% of the surface area of each framed cloth to 
provide hiding places for fallen curculios. Plum 
curculios fall frequently from limbs of host trees 
(sometimes more than once per day) onto the 
ground beneath in response to perceived dan- 
ger or adverse weather. We reasoned that tap- 
ping curculios from branches and allowing them 
to fall on cloth provided with shelter effectively 
mimicked natural behavior and conditions. 

As soon as four or five curculios (first study) 



or eight curculios (second study) accumulated 
on the cloth, we quickly but gently carried the 
frame and cloth to a position half-way between 
the trunk and canopy edge of a nearby semi- 
dwarf unmanaged apple tree (first study) or 
plum tree (second study). There were no 
curculio traps of any sort in the vicinity of the 
apple tree. One unbaited black p3rramid trap 
was placed next to the trunk and another at 
the edge of the canopy of the plum tree, with 
the framed cloth centered between and equi- 
distant (4 feet away) from either trap. Dressed 
in white cap, shirt, and shorts that hopefully 
were invisible to curculios, one of us knelt down 
nearby the cloth and quietly observed the pro- 
portion of curculios that departed the cloth by 
flight or by crawling and the proportion that 
moved to hide beneath foliage or rested on the 
cloth. Observation periods lasted 1 hour. They 
were evenly spaced among 1-hour intervals be- 
ginning at 8 AM and ending at 8 PM in the first 
study, or among 1-hour intervals beginning at 
2 PM and ending at 6 PM in the second study. 
In both studies, observations commenced a day 
or two after petal fall and extended over a 3- 
week period thereafter. We recorded the direc- 
tion taken by each adult upon departure from 
the cloth and continued to track adult destina- 
tion until it was lost fi"om sight. 

Results 

Of the 166 plum curculios observed beneath 
the apple tree, 52 (31%) left the framed cloth by 
flight and 27 (16%) by crawling. The remain- 
der moved to hide beneath foliage on the cloth 
(18%) or rested in place (35%). Among curculios 
that flew, significantly more (54%) flew toward 
the tree canopy above than flew toward inter- 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



11 



Table 1. Type 


and direction of movement of 166 plum 


cu 


rculio adults observed on a framed 


cloth beneath an apple tree during 


1-hour periods evenly 


distributed from 8 AM to 8 PM. 


Type of 


Number engaged 


Movement 




Curculio movement in each 


movement 


in movement 


direction toward 


direction (% of movement category)* | 


Flew 


52 


Tree trunk 

Tree canopy 

Inter-tree space 

Grass 




17b 

54a 

25b 

4c 


Crawled off 


27 


Tree trunk 
All others 




88a 
12b 


Hid 


30 


- 




- 


None (rested) 


57 


- 




- 


* For each category of movement, 


numbers followed 


by 


a different letter are significantly 


different at ode 


Is of 19:1. 









tree space (25%), the tree trunk (17%), or grass 
beneath the canopy (4%) (Table 1). Among 
curcuhos that crawled, significantly more (88%) 
crawled toward the tree trunk than toward all 
other directions combined (12%) (Table 1). 

Of the 104 plum curculios observed beneath 
the plum tree, 39 (38%) left the framed cloth by 
flight and 19 (18%) by crawling. The remain- 
der moved to hide beneath foliage on the cloth 
(13%) or rested in place (31%). Among those 
that flew, significantly more flew toward the tree 
canopy above (36%) or toward inter-tree space 
(38%) than toward the pyramid trap at the tree 



trunk (15%), the pyramid trap at the canopy 
edge (3%) or grass beneath the canopy (8%) 
(Table 2). Among curculios that crawled, sig- 
nificantly more (74%) crawled toward the pyra- 
mid trap at the tree trunk than toward the pyra- 
mid trap at the canopy edge (10%) or toward 
other directions (16%) (Table 2). 

Temperatures taken beneath each tree at 
the time of observed curculio movement indi- 
cated that no flight occurred at temperatures 
of 67°F or less. Also, there was a significant 
positive correlation between temperature and 
proportion of total observed curculios that flew. 



Table 2. Type and direction of movement of 104 plum curculio adults observed on a framed cloth 


beneath a plum tree during 1-hour 


periods evenly distributed from 2 PM to 6 PM. 1 


Type of Number engaged 


Movement direction 


Curculio movement in each 


movement in movement 


toward 


direction (% of movement category)* 


Flew 39 


Trap at tree trunk 


15b 




Trap at canopy edge 


3c 




Tree canopy 


36a 




Inter-tree space 


38a 




Grass 


Bbc 


Crawled off 19 


Trap at tree trunk 


74a 




Trap at canopy edge 


10b 




All others 


16b 


Hid 14 


- 


- 


None (rested) 32 


- 


- 


* For each category of movement, 


numbers followed by a different letter are significantly | 


different at odds of 19:1. 







12 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



On the other hand, a substantial proportion of 
those curcuhos observed to crawl off the cloth 
(about 20%) did so at temperatures of 67°F or 
less, and there was no correlation between tem- 
perature and proportion of total observed 
curculios that crawled off. 

Conclusions 

The more robust data reported here confirm 
and extend the preliminary data reported in the 
1997 Winter issue of Fruit Notes. Combined 
data indicate that when the air temperature is 
67°F or less beneath the canopy of a host tree, 
the plum curculio adults that have dropped from 
the tree canopy (as they normally do on a fre- 
quent, even daily, basis) are reluctant or unable 
to fly but are able to reenter the tree canopy by 
crawling. Crawling is almost exclusively toward 
the tree trunk, or if a black pyramid trap is 
adjacent to the tree trunk, then toward such a 
trap, which is thought to be a visual mimic of a 
tree trunk. At temperatures of 68°F or greater, 
curculios exhibit an increasing propensity to 



reenter the tree canopy by flight. Most flights 
are into the tree canopy. Only a small propor- 
tion (15-17% according to our findings here) is 
toward the tree trunk or a black pyramid trap 
next to the tree trunk. Hence, at temperatures 
of 68°F or greater, there is only a small chance 
of capturing a tree-reentering curculio using a 
black pyramid trap. Other data that we col- 
lected in 1997 show that curculio damage to tree 
fruit increases with increasing temperature. It 
is therefore doubtful that any prospective 
unbaited curculio traps placed in association 
with the tree trunk will be able to monitor 
curculio entry into or abundance in the tree 
canopj/^ in a way that reflects accurately the 
probability of curculio damage to fruit. 



Acknowledgments 

This work was supported by a grant from the 
USDA Northeast Regional IPM Competitive 
Grants Program and the New England Tree 
Fruit Research Committee. 



*X* *X* *X^ *^ *X* 

#Y* *Y* *T* *T* *T* 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



13 



Toward Traps Alternative to Black 
Pyramids for Capturing Plum Curoulios 

Ronald Prokopy, Bonnie Dixon, and Tracy Leskey 
Department of Entomology, University of Massachusetts 



In the two preceding articles, we concluded 
that unbaited black pyramid traps (and prob- 
ably all other unbaited traps) aimed at captur- 
ing plum curculios intent on entering host trees 
by crawling or flying onto tree trunks are un- 
satisfactory for monitoring curculios in a way 
that reflects accurately the potential for curculio 
damage to fruit. In the 1997 Winter issue of 
Fruit Notes, we presented results of a prelimi- 
nary test in 1996 showing that sticky-coated 
squares of clear Plexiglas positioned just out- 
side of apple tree canopies captured about as 
many plum curculio adults as black pyramid 
traps next to tree trunks. Here, we report on a 
1997 study further comparing these two trap 
types. We also report preliminary results on a 
potentially useful third trap type. 

Materials and Methods 

The first study was carried out in a small 
block of unmanaged semi-dwarf apple trees at 
Hampshire College in South Amherst. The 
Plexiglas traps were designed to capture plum 
curculios fl3ring toward tree canopies from over- 
wintering sites or from other host trees. Each 
trap was constructed of clear Plexiglas (2 feet 
by 2 feet) attached 
vertically on a 
wooden pole posi- 
tioned 2 feet away 
from the edge of the 
tree canopy. The 
outer-facing but 
not the inner-fac- 
ing surface of the 
Plexiglas was 
coated with 

Tangletrap to cap- 



ture curculios flying toward the tree canopy. 
Two such traps were attached to each pole, one 
opposite the lowermost foliage and the other 
opposite the uppermost foliage. Two poles with 
traps were placed on opposite sides of each of 
six trees. Two unbaited black pyramid traps 
were placed on opposite sides of and immedi- 
ately next to the trunks of each of six other trees. 
All traps were emplaced at the beginning of 
apple tree bloom (May 24) and were examined 
daily thereafter for 22 days for captured 
curculios. Each day, 16 fruitlets on each of the 
12 trees were examined for evidence of plum 
curculio damage. Each day, temperature, rela- 
tive humidity, and wind speed were recorded. 
The second study was carried out in two 
unmanaged apple trees, one in Amherst and one 
in Conway. Traps were designed to capture 
plum curculios that had already arrived in tree 
canopies and were searching for resources of 
fruit borne on twigs or resting sites on twigs. 
Each trap, constructed of cardboard, was cylin- 
drical in shape (8 inches tall and either 1 or 3 
inches in diameter), coated with yellow or black 
latex paint, and capped with an inverted screen 
funnel developed originally to capture boll wee- 
vils. The yellow cylinders were intended to 



Table 1. Numbers of plum curculios captured daily by traps in 
unmanaged apple trees. May 24 - June 15, 1997. 



Traps 



Clear Plexiglas, low position 12 

Clear Plexiglas, high position 12 

Black pyramid traps 12_ 



Number of Mean number of curculios 
replicates captured per trap * 



10.0 a 
7.6 a 
9.1a 



* Numbers followed by a different letter are significantly different at 
odds of 19:1. 



14 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



Table 2. Of plum curculios that left vials in which they were contained (i.e. 
curculios that were active), proportions that arrived on vertical apple twigs 
(1/2 inch diameter) or on cylindrical vertical mimics (1 or 3 inches diameter) 
of either apple twigs (black) or apple foliage and fruit (yellow). 





Number 


of 


Curculios that arrived on 


Structure 


active curculios 


tested structure (% of active)* 


Twigs 


52 




24 b 


Yellow cylinder (1 inch) 


59 




22 b 


Yellow cylinder (3 inches) 


54 




24 b 


Black cylinder (1 inch) 


61 




41a 


Black cylinder (3 inches) 


54 




48 a 



* Numbers followed by a different letter are significantly different at odds of 
19:1. 



mimic foliage and fruit borne by twigs and were 
similar in appearance to yellow-green plastic 
traps used commercially to capture cotton boll 
weevils. The black cylinders were intended to 
mimic twigs themselves. Each cylinder was po- 
sitioned vertically on a branch over an upright 
clipped twig, used as support. For each trial, 
we collected curculios (by branch tapping) from 
nearby trees, placed ten in a vial, and attached 
the vial in horizontal position to a branch about 
9 inches from a cylinder. The curculios could 
crawl or fly directly from the vial opening to- 
ward the cylinder. Of the curculios that left 
vials, we recorded proportions that arrived on 
a cylinder during a 30-minute trial period. 

Results 

There were no significant differences in 
numbers of curculios captured per trap among 
sticky-coated Plexiglas traps in low position, 
sticky-coated Plexiglas traps in high position, 
and black pyramid traps (Table 1). These re- 
sults confirm and are remarkably similar to 
those of the 1996 study reported in the 1997 
Winter issue of Fruit Notes. Importantly, we 
found here that increases in captures by sticky 
Plexiglas traps but not by black pyramid traps 
were significantly positively correlated with 
increases in fruit damage caused by plum 
curculios the following day. Also, captures by 



sticky Plexiglas traps as well as fruit damage 
were significantly positively correlated with 
temperature, with the former also significantly 
negatively correlated with wind speed. 

Among plum curculios that left vials in 
which they were released on apple tree 
branches, 22-24% arrived on upright test twigs 
or on 1 -inch-diameter or 3-inch-diameter up- 
right yellow cylinders (Table 2). Significantly 
greater proportions (41-48%) arrived on upright 
black cylinders (Table 2). All observed curculios 
arrived on twigs and cylinders by crawling. 
None arrived by flight. 

Conclusions 

The findings reported here, though still pre- 
liminary, encourage us to believe that improved 
variants of the sticky Plexiglas squares and tall 
black cylinders studied here could be more suit- 
able than black pyramids for monitoring 
curculios, because captures by these traps bet- 
ter coincide with periods of curculio damage to 
fruit than captures by black pyramid traps. 
Sticky Plexiglas squares placed adjacent to tree 
canopies are much too cumbersome for wide- 
spread use by growers, but a simplified non- 
sticky version (possibly incorporating attractive 
canopy-mimicking stimuli) might be an effec- 
tive substitute. Similarly, an improved version 
of a black twig-mimicking trap could be of con- 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



15 



siderable value in monitoring within-canopy 
activity of curculios. We are planning further 
studies on these alternative trap types. 



Acknowledgments 

This work was supported by grants from the 
USDA Northeast Regional IPM Competitive 
Grants program and the New England Tree 
Fruit Research Committee. 



•X^ •^ *^T> vL* *1>* 

rp» 0^ 0^ #^ 0^ 



16 



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BIOLOG'GAL 

FEB K 
FEB 2 4 1999 



\'/ 




Volume 63, Number 2 
SPRING ISSUE, 1998 

Table of Contents 



Residues of Azinphosmethyl on Apples 
Using First- vs. Third-level IPM 

Can Apple Maggot Fly Control Benefit from Sprays of Provado 
Aimed at Killing Leafminers and Leafhoppers? 

Tax Pointers for Farmers and Landowners in 1998 

Preliminary Study of 1PM Options for Peaches: 
Major Fruit-damaging Insects 



Fruit Notes 



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Residues of Azinphosmethyl on 
Apples Using First- vs. Third-level IPM 

Starker Wright and Ronald Prokopy 

Department of Entomology, University of Massachusetts 

Scott Carrier, Raymond Putnam, and J. Marshall Clark 
Massachusetts Pesticide Analysis Laboratory 



The apple maggot fly ( AMF) is a key summer pest 
of apples in New England and other parts of eastern 
North America. According to recent surveys, AMF 
was ranked as one of the two most important insect 
pests attacking apple fruit by commercial apple grow- 
ers in Massachusetts [Fruit Notes 61(3)]. AMF are 
active in orchards from late June through mid-Septem- 
ber, with peak activity generally in early August. Most 
growers are able to achieve effective control of AMF 
by applying two to four insecticide sprays during July 
and August. 

Over the past two decades, we have attempted to 
develop an alternative behavioral approach to AMF 
control. This approach involves surrounding an or- 
chard block with odor-baited red spheres placed about 
5 yards apart on perimeter trees. Each sphere is either 
coated with Tangletrap or is treated with a feeding 
stimulant and an insecticide to kill alighting flies [Fruit 
Notes 62(4)]. Ideally, this system of management 
would allow the grower to cease insecticide applica- 
tion after plum curculio season, in effect extending the 
pre-harvest interval for summer insecticide use to 80 
days or more. One grower-perceived advantage to be- 
havioral control of AMF is reduction in use of sum- 
mer insecticides and subsequent reduction in level of 
insecticide residue on fruit at harvest [Fruit Notes 
60(4)]. 

The EPA sets standards for commercially accept- 
able levels of pesticide residue on marketed fruit. 
Currently, the standard for azuiphosmethyl residue on 
apples is 2 parts per million (2000 parts per billion). 
However, the Food Quality Protection Act (FQPA) may 
strongly affect tolerable levels of residue. The intent 
of the FQPA is to establish tolerance levels that are 
?safe,? defined as ?a reasonable certainty that no harm 



will result from aggregate exposure, including all ex- 
posure from diet, drinking water, and other non-occu- 
pational exposures.? In order to calculate health risks 
associated with exposure to pesticide residues, the 
FQPA dictates that aggregate exposure be measured 
by use of a ?risk cup,? meaning that all exposures (fresh 
and processed foods, water, and household exposure) 
are combined into the same cup. All existing toler- 
ances must be re-evaluated, and organophosphate in- 
secticides (such as azinphosmethyl) are included in the 
first round of review, slated for completion in August 
of 1 999. Tolerance levels are based on residues present 
on fruit at harvest. 

Our aim here was to determine the amount of 
azinphosmethyl on fniit at harvest in blocks of apple 
trees that received azinphosmethyl for AMF control 
versus blocks that received only odor-baited red spheres 
for AMF control. 

Materials & Methods 

In 1997, we began a pilot third-level IPM project 
in order to determine the influence of apple tree archi- 
tecture and planting density on biologically-based pest 
management and fruit quality. In each of eight com- 
mercial orchards, we identified and flagged six blocks 
of trees: two each of high, medium, and low tree den- 
sity. One block of each density was managed under 
first-level IPM practices that involved application of 
two to four sprays of insecticide from early July to 
harvest. The other block was managed under third- 
level practices that involved surrounding the block with 
odor-baited red spheres. For purposes here, fruit were 
sampled only from the medium-density trees, which, 
at -240 trees/acre, represent the majority of apple trees 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



rablu I. A/inphosiiiclhyl ihsccIickIl- appliciilions. a/.inpliosiiKiliyl icsidiics and AMI' in|iiry on luiil al 
liarvcsl 111 blocks iiianaL'cd under liisl Il-vl-I vcislis ihird-lcvcl II'M in live eoinnicieial apple oreliards 



Orchard 



Dales ol 

azinphosmcthyl 

applieations 



Dt)sage 

equivalcnl per 

application'' 



A/Jnphosnielhyl 
residue at harvest (pph) 



AMF injury 
(%) 



First 

Level 

IPM 

Blocks 



C 



D 



Mean 



Third 

Level 

IPM 

Blocks 



B 


C 



D 



Mean 



May 


20 


June 


3 


July 


20 


August 


2 


May 


29 


June 


6 


June 


13 


July 


10 


August 


6 


May 


28 


June 


7 


June 


23 


July 


16 


July 


31 


August 


14 


June 


5 


June 


13 


August 


7 


August 


26 


May 


25 



June 
June 
June 
July 
August 
August 



9 

20 
30 
21 
11 
30 



1,5 

1.0 

0.25 

0.25 

0.67 

0.67 
1.3 
0.7 

0.67 
1 .0 
1.0 
0.5 
1.0 
1.0 
1.0 
1.0 
1.0 
0.5 

0.25 
LO 
1.3 

0.67 
1.3 
1.0 

0.67 

0.67 



4.37 



May 


20 


1.5 


June 


3 


1.0 


May 


29 


0.67 


June 


6 


0.67 


June 


13 


1.3 


May 


28 


1,0 


June 


7 


1.0 


June 


23 


0.5 


May 


14 


0.25 


June 


5 


1.0 


June 


13 


1.0 


May 


25 


1.0 


June 


9 


1.3 


June 


20 


0.67 


June 


30 


1.3 



2.83 



N/D'' 



80 



239 



N/D" 



159 



96 



N/D" 



N/D" 



N/D'' 



N/D'' 



N/D" 



0.0 



0.0 



0.0 



0.0 



LO 



0.2 



2.0 



0.0 



0.0 



0.0 



0.0 



N/D' 



0.4 



One dosage equivalent = 8 o/.. formulated a/inphosniethyl per 100 gallons water. 



Applications in May and June were made against plum curculio, 
' ppb: parts per billion. 
'' N/D: not detected (detection limit = 40 ppb). 



Fruit Notes, Volmne 63 (Number 2), Spring, 1998 



in Massachusetts. Of the eight medium-density third- 
level IPM blocks and the eight companion first-level 
blocks, five pairs were selected for sampling here. Se- 
lection was based on the fact that azinphosmethyl was 
the insecticide applied against AMF in all five first- 
level blocks. 

Within one week of harvest, ten mid-sized Mcin- 
tosh fruit were selected randomly from each block, 
bagged, and placed within 6 hours in a deep-freeze at 
?20"C until the analyses were performed. Fruit forti- 
fied with known levels of azinphosmethyl showed that 
there is no significant breakdown of residues while in 
storage. From each experimental block, three samples 
were analyzed, each sample consisting of three fruit. 
For analysis details, see the note at the end of the text. 

Results 

In the five blocks under first-level IPM, growers 
used an average of 2.4 sprays against AMF between 
early July and late August, resulting in an average of 
0.2% AMF injury (Table 1). Analysis revealed that 
fruit treated with 2-3 sprays of azinphosmethyl con- 
tained an average of 95.6 parts per billion of 
azinphosmethyl residue at harvest, roughly 5% of the 
current EPA tolerance. 

In keeping with the principles of behaviorally- 
based AMF control, no insecticides were applied to 
the five third-level IPM blocks after mid-June. 
Expectedly, none of the samples taken from these 
blocks contained a detectable level of azinphosmethyl 
residue, even though these blocks received an average 
of 2.8 applications of azinphosmethyl against plum 
curculio in May and June (Table I ). Blocks managed 
under third-level practices received slightly more in- 
jury by AMF (0.4%) than did first-level blocks. 

Conclusions 

This study has shown that the amount of 
azinphosmethyl residue present on apples at harvest 
in 1997 in test blocks managed under first-level IPM 
practices averaged far less (about 95% less) than the 
amount of residue allowed by current EPA regulations. 
This study also showed that no detectable residues of 
azinphosmethyl were found on apples at harvest in test 
blocks managed under third-level IPM practices. 

Although it may seem logical that no insecticide 
treatment during July and August (as under third-level 
1PM) ought to result m no insecticide residue on frait 



at harvest, such would not necessarily be the case if 
insecticide applied against plum curculio were to be 
present on harvested fruit. All ten blocks in this study 
received two to four sprays of azinphosmethyl from 
mid-May to late June against plum curculio. Our data 
from fruit samples taken in third-level IPM blocks 
clearly show that treatments of azinphosmethyl applied 
in May and June did not result in detectable levels of 
azinphosmethyl on harvested fruit (Table I). This in- 
formation could be important to EPA consideration of 
continued allowable use of azinphosmethyl against 
plum curculio. 

Even though our findings here indicate that use of 
third-level IPM practices results in no detectable resi- 
dues of azinphosmethyl on fruit at harvest and pro- 
vides acceptable commercial-level control of AMF, 
more work is needed to refine third-level IPM prac- 
tices so that they will become as economical and reli- 
able as first-level IPM practices. 

Acknowledgments 

This work was supported by state/federal IPM 
funds and USDA SEA CSREES Grant # 97-34365- 
5043. We are grateful to the eight growers that par- 
ticipated in this study: Bill Broderick, David Chan- 
dler, David Cheney, Dana Clark, David Shearer, Joe 
Sincuk, Tim Smith, and Mo Tougas. 



Note: Whole fruit were blended with water and sub- 
mitted to extraction with ethyl acetate, then reduced 
using a sample concentrator, leaving a concentrate of 
residual material. Azinphosmethyl residues from ex- 
tracted apples were analyzed using a Varian model 3400 
GC gas chromatograph (Varian Associates, Sunnyvale, 
CA) equipped with a nitrogen phosphorous detector 
(NPD). The capillary column was a fused silica DB-5 
liquid phase, 0.53 mm i.d. X 1 5 m, 0.25mm film thick- 
ness (J & W Scientific). A deactivated cyclodouble- 
gooseneck injection port liner (Restek, Bellefonte, PA) 
was used for splitless injections. Operating conditions 
were as follows: injection volume, 1.0 ml; injection 
port temperature, 250"C; detector temperature, 300"C; 
column temperature, 1 75"C for 0.5 min, ramped at 
20'C/min to 250"C and held for 12 min. The carrier 
gas was helium at a rate of 8 ml min '. Detector gas 
flow rates were: nitrogen, 25 ml min'; oxygen, 175 
ml min ': hydrogen, 2.5 ml min ' (Kadenczki et al., J. 
Assoc. Off. Anal. Chem. 75, No.l, 53-61). 



%f^ «t# m^A %£• aI^ 
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Fruit Notes, Volume 63 (Number 2), Spring, 1998 



Can Apple Maggot Fly Control Benefit 
from Sprays of Provado Aimed at 
Killing Leafminers and Leafhoppers? 

Xing Ping Hu, Andrew Kaknes, and Ronald Prokopy 
Department of Entomology, University of Massachusetts 



The insecticide Provado (containing imidacloprid 
as the active ingredient) was synthesized by Japanese 
Chemists in 1985. In 1995, it was labeled for use on 
apple in the United States. One of its greatest perceived 
advantages is its high toxicity to several major apple 
pests but comparative lack of toxicity to beneficial 
predators and parasitoids. Indeed, Provado has proven 
very effective against leafminers, leafhoppers, and 
aphids in apple orchards of Massachusetts and other 
states [Fruit Notes 60(4)]. Provado may be used ef- 
fectively when applied against either first-generation 
leafminers and leafhoppers at petal fall in May, or 
against second-generation leafminers and leafhoppers 
in late June. Application in late June conceivably also 



could provide control of early-invading populations of 
apple maggot flies. One reason for believing this might 
be so stems from recent tests of Provado applied, to- 
gether with latex paint, on red spheres aimed at killing 
alighting apple maggot flies. Results of these tests 
showed high toxicity of Provado against the flies even 
at very low doses [Fruit Notes 62 (4)] . Here, we evalu- 
ated effects of Provado against apple maggot flies when 
applied to the foliage and fruit of apple trees. 

Materials & Methods 

Provado was provided by Bayer Corporation (Kan- 
sas City, MO). Flies used in bioassays were obtained 



>. 

o 
E 

u. 



40 
35 
30 
25 
20 
15 
10 

5 i 




— •— Flies caged immediately following spray 
-•— Flies caged 24 hours after spray 
-•— Flies caged on insprayed leaves 



1 



I 

4 



6 



2 3 4 5 

Days of exposure to sprayed foliage and fruit 

Figure 1 . Mortality of apple maggot flies caged on apple trees sprayed with Provado (0.03% a.i.). 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 





35 




30 


^ 




0) 




Si 


?5 


h 




3 
C 


20 


C 




ra 


IS 


0) 




S 


10 




5 








D Flies caged immediately following spray 

■ Flies caged 24 hours after spray 

■ Flies caged on unsprayed leaves 






Oviposition puncture 



Eggs laid 



Egg load 



Figure 2. Mean number of oviposition punctures, eggs laid, and egg load per female among 
apple maggot Hies that survived exposure to Provado during 7 days in field cages 



from pupae collected from unsprayed apple drops. Five 
apple trees were selected from an abandoned orchard 
near Amherst, Massachusetts. Branches of four trees 
were sprayed to runoff at a dose of 0.03% a.i. of 
Provado, the rate labeled for controlling sucking in- 
sects in apple orchards. The fifth tree was not sprayed 
and used as a control. For each tree, four branches 
were selected for caging flies, using 30x50-cm cloth 
screen net. Two fruit were allowed to remain on each 
branch. Four leaves on each branch received an aque- 
ous slurry of a mixture of 8% sugar and 10% bird drop- 
pings to serve as a food supply for flies. Two cages 
per tree received 20 flies (10 males and 10 females) 
immediately following spray application. The other 
two cages received like numbers of flies 24 hours later. 
Mortality counts were made daily for 7 days. To 
determine possible effects on fly reproduction, apples 
and surviving flies from each cage were brought back 
to the laboratory on the 7"' day. Apples were exam- 
ined to detemiine the effects of Provado on fly ovipo- 
sition behavior by counting the number of oviposition 
punctures and number of eggs laid. Female flies were 
dissected to determine effects of Provado on egg load 
by counting the number of mature eggs in fly ovaries. 

Results 

Our results indicate that application of Provado to 
apple tree foliage and fruit neither effectively reduced 
fly survival (Figure 1 ) or fly reproductive ability (Fig- 



ure 2). Less than 20% of flies caged immediately after 
spray application were killed over the 7-day test pe- 
riod, too low to provide effective control. Mortality 
was even lower (8%) for flies released into cages 24 
hours after spraying. This was essentially no greater 
than the 5% mortality of flies in the control cages. The 
results suggest a rapid decline of Provado activity on 
leaf and fruit surfaces after application. 

Figure 2 shows that fly oviposition behavior was 
only slightly reduced for flies exposed to sprayed com- 
pared with unsprayed leaves and fniit. Groups of flies 
exposed to foliage and fruit immediately after spray- 
ing with Provado made an average of 16 ovipositional 
punctures and laid an average of 14 eggs over 7 days, 
compared with 1 9 ovipositional punctures and 1 7 eggs 
laid by tlies expo.sed to foliage and fruit 24 hours after 
spraying, and 21 ovipositional punctures and 19 eggs 
laid by control flies. The egg load per female remained 
at essentially the same level for all the treatments. 
These results suggest that Provado applied to apple 
foliage and fruit had minimal effects of fly oviposi- 
tion. 

Conclusions 

Even though Provado has proven excellent in pro- 
viding season-long control of .sucking in.sect pests on 
apple trees, and even though our laboratory tests 
showed high toxicity of Provado to apple maggot flies, 
the results generated here indicate that Provado ap- 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



plied to apple tree foliage and fruit has little or no ef- 
fect on apple maggot fly mortality and oviposition. 
There may be two reasons for the ineffectiveness of 
Provado spray on tree foliage and fruit against apple 
maggot flies. First, Provado is a systemic insecticide, 
and is quickly absorbed by foliage (and perhaps also 
fmit) once sprayed. Thus, it kills pests that suck sap 
from the interior of foliage but does not remain on plant 
surfaces long enough to kill pests, such as apple mag- 
got flies, that do not suck plant sap. Second, Provado 
on exterior surfaces of plants is subject to rapid degra- 
dation by sunlight. Nevertheless, when applied to- 
gether with latex paint to red spheres, Provado, even 
at very low doses, has provided excellent control of 
apple maggot flies alighting on treated spheres for up 



to three months after initial application. Thus far, it 
has proven more effective than any other insecticide 
that we have evaluated for this purpose. 



Acknowledgements 

We thank Richard H. Ackerman from Bayer Cor- 
poration for providing us with samples of imidacloprid 
and John Clark and David Ferro from our department 
for helpful suggestions. This work was supported by 
funds from USDA Cooperative Agreement 58-3620- 
104, the Northeast Regional IPM Competitive Grants 
programs and the Washington State Tree Fruit Research 
Commission. 



«t« «t« %f# %% ftl^ 
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Fruit Notes, Volume 63 (Number 2), Spring, 1998 



Tax Pointers for Farmers and 
Landowners in 1998 



P. Geoffrey Allen 

Department of Resource Economics, University of Massachusetts 



Tax advice given below is intended as general 
advice and is believed to be correct. It does not 
substitute for a detailed review of the circumstances of 
an individual taxpayer by a professional tax 
practitioner. For more details, you and your tax 
adviser may wish to consult the sources referenced in 
the square brackets [thusj (see footnote). Taxpayers 
filing returns other than for calendar year 1998 may 
face different rules than those described here . 

New Legislation 

Life seems to be getting ever more complicated. 

• On January 1 , 1 998, many of the provisions of the 
Taxpayer Relief Act of 1997 "TRA97" (Public 
Law 105-34) became effective. 

• On July 22, 1998, the IRS Restructuring and 
Reform Act/ Taxpayer Bill of Rights 3 
"RRA98"(H.R. 2676) was enacted mto law (P.L. 
105-206), and many of its provisions became 
effective on that date. While mostly concerned 
with internal operations of the IRS, changes in 
laws governing collection of taxes and "innocent 
spouse" provisions will affect some taxpayers. 
The Act also makes technical corrections to 
TRA97 that affect treatment of some capital gains 
and losses and sale of a principal residence. 

• Finally, as the last act of the 105"" Congress, the 
Omnibus Appropriations Act for FY99 "OAA99" 
(H.R. 4328) was enacted into law on October 21, 
1998 as P.L. 105-277. It contains several 
retroactive tax provisions of specific interest to 
farmers. They are discussed below. 

Income Averaging for Farmers 
Made Permanent [IRC §1301] 

TRA97 introduced income averaging for farmers 
for 1998-2000. OAA99 made the averaging provisions 



permanent. 

Use income averaging if you had a successful year 
in 1 998 and less profit in prior years. The idea is to shift 
some of your income from the high marginal tax rate 
you would otherwise face in 1998 to the rate it would 
have been taxed in earlier years. Schedule J of Form 
1040 is used for calculations. 

Step 1 . Calculate the tax on your taxable income (farm 
and non-farm) in 1998. If the last dollar of income is in 
a higher tax bracket than the last dollar of taxable 
income in any of the three prior years then income 
averaging will reduce your 1998 taxes. 

Step 2. Elect the amount of farm income to be 
averaged. Only farm income can be averaged. 
However, if your family has high taxable income in 
1998 because of both farm and non-farm income, you 
can average the farm income part. Farm income 
includes gains from the sale of assets (except land) 
used in the farming business for a "substantial period" 
(not defined). Sales of machinery and breeding 
livestock reported on Form 4797 would be eligible. 
Elect as much of the current year's eligible farm 
income as you want to distribute over the three prior 
years. The principle is to get income after averaging 
approximately level across the years. The more 
detailed operational rule is explained after the 
example. 

Step 3. Divide the elected amount of income into three 
equal parts and add each part to your taxable income 
(farm and non-farm) in each of the three prior years. 
Subtract the elected amount from 1998 income. 

Step 4. Using the income levels from step 3, figure the 
tax for each year using the tax table for that year and 
add the tax amounts together. 

Step 5. Add the actual taxes paid in the three prior 
years to the 1 998 taxes from step 1 . 

Step 6. Compare the total from step 4 with the total 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



Irom step 5 H the total from step 4 is smaller then 
income averaging will be advantageous. 

Example: Andy Farmer, who is married, filing 
jointly, has both farm and non-farm income for the last 
four years as shown in Table I . Net losses are within 
parentheses. If Andy does not elect income averaging 
then the family income tax liability for 1998 will be 
$32,346. [. 1 5 X $42,350 + .28 x ($ 1 02,300 - $42,350) 
+ .31 x ($132,000 - $102,300)]. Andy can elect to 



Table 1 


Taxable income 


and tax before 


averaging. 




Year 


Taxable 
income 


Tax on 

unaveraged 

income 


Income 
reported on 
Schedule F 


Livestock and 

machinery 
gains reported 
on Form 4797 


1995 
1996 
1997 
1998 


$6,000 

$8,000 

$11,000 

$132,000 


$900 

$1,200 

$1,650 

$32,346 


$(14,000) 

$(10,000) 

$(8,500) 

$114,000 


$4,000 
$1,500 
$2,000 
$3,000 


Total 


tax 1995-98 


$36,096 






1 



average up to $ 1 1 7,000 of 1 998 income (the total of the 

Schedule F and Form 4797 amounts). If he elects to 

average $90,000, then $30,000 is added to the taxable 

income of 1995, 1996 and 1997. Results of averaging 

are shown in Table 2. 

Note that if Andy elects 

to income average in 

1999 the amounts in 

Table 2 become the 

initial taxable incomes. 

The saving from 

averaging is $12,546 [= 

$36,096 - $23,550]. The 

1998 tax liability is 

$19,800 [$23,550 -$900 

-$1,200 -$1,650]. Note: 

the tax is figured at 15% 

of taxable income. U.se 

of tax tables will give 

slightly different answers 



($4 more m each case). 

The operational rule is to increase the amount of 
the election as long as the average marginal tax rate 
over the three prior years is as low or lower after 
averaging than the marginal rate on the income 
remaining in 1998. In the example, the last dollar of 
taxable income before averaging (Table 1 ) in each of 
the prior years is taxed at 15%, against the marginal 
rate for 1998 of 31 %. Therefore, moving $3 from 1998 
to the prior years reduces the tax rate on that income 

from 31% to 15%. After 
averaging (Table 2) the 
marginal rates are 15% 
throughout. 

If the election was 

increased by more than 

$600 (to over $90,600) 

this would bring 1997 

taxable income over 

$41,200, increasing the 

marginal rate of tax in 

1997 to 28%. Now the 

average marginal tax 

rate of the three prior 

years (15% -i- 15% -f- 

28%)/3 = 19.3%> exceeds 

the marginal rate for 

1 998, which has dropped 

to 15%. 

Caution: If you are subject to alternative minimum 

tax in the year for which averaging is elected ( 1 998 in 

the example) then income averaging will be of no 

benefit. 



Table 2. 


Taxable income 


and tax after averaging. 




Year 


Taxable income 


Lndof IS'/r taxable 
income bracket 


Tax on averaged 
income 


1995 
IW6 
l'W7 
1998 


$36,000 
$38,000 
$4 1 ,000 
$42,000 




$39,000 
$40,100 

$41,200 
$42,350 


$5,400 
$5,700 
$6, 1 50 
$6,300 








Total lax 1995-98 


$23,550 





Fruit Notes, Volume 63 (Number 2), Spring, 199cS 



Averaging Does Not Alter 
Self-employment Tax [IRC §1301] 

Andy's self-employment tax in 1998 in the 
example above would be $11,535. [92.35% of 
$114,000 = $105,279. The first $68,400 is taxed at 
15.3% = $10,465. The balance. $105,279 - $68,400 = 
$36,879 IS taxed at 2.9% = $1070.] Income averaging 
does not change the self-employment tax amount. 

Conservation Reserve Payments Are 
Rent Not Farm Income, Are Not Subject to 
Self-employment Tax, and Are Reportable on 
Schedule E [Wuebker vs Commissioner, 1 10 
T.C. No. 31 (June 23, 1998); IRC §1402] 

For several years the IRS has taken the position 
that Conservation Reserve Program (CRP) payments 
to materially participating farmers are subject to 
self-employment tax. (If you do not fall under the 
material participation rules, see below, you were not 
and still are not subject to SE tax on CRP payments.) . 
The Tax Court in the Wuebker case determined that 
CRP payments are rent; however, CRP agreements 
prevent the land from being used for agricultural 
production. Therefore, the language in IRC § 1402 that 
called for the payment of SE tax on rent by a materially 
participating farmer does not apply. The IRS may 
appeal the Court's decision. 

Note: There are reasons why you might not wish to 
treat CRP payments as rent. Some estate tax benefits 
might be lost. For example, to get the favorable 
valuation as farmland rather than fair market value (in 
highest and best use), the deceased owner must have 
materially participated in using the land for farming 
purposes. In this situation, you would want to report 
the CRP payments on Schedule F and pay SE tax on 
them. If taking this position, filing the disclosure form, 
Form 8275, is probably wise, relying on the past IRS 
position and its likely appeal of the Wuebker decision. 
[IRC § 1402(a)(1)] 

Material Participation 

There are two sets of material participation rules. 
A taxpayer who is materially participating for the 
purposes of self-employment tax may or may not be 
materially participating for the puqjo.ses of passive 



activity loss rules. The reverse is true: a taxpayer who 
materially participates for the purposes of passive 
activity loss rules may not be materially participating 
for the purposes of self-employment tax. 

The Farmer's Tax Guide (IRS Publication 225) 
lists the tests of material participation of a farm- 
landlord to determine whether or not self-employment 
tax must be paid. You are materially participating if 
you have an arrangement with your tenant and you 
meet one of the following tests: 

Test No. 1 . You do any three of the following: ( 1 ) pay 
or stand good (e.g. sign for materials bought on credit) 
for at least half the direct costs of producing the crop; 
(2) furnish at least half the tools, equipment, and 
livestock used in producing the crop; (3) consult with 
your tenant; and (4) inspect the production activities 
periodically. 

Test No. 2. You regularly and frequently make, or take 
an important part in making, management decisions 
substantially contributing to or affecting the success of 
the enterprise. 

Test No. 3. You work 1 00 hours or more spread over a 
period of 5 weeks or more in activities connected with 
crop production. (Note: these numbers do not appear in 
either the tax code or the regulations.) 

Test No. 4. You do things which, considered in their 
total effect, show that you are materially and 
significantly involved in the production of the farm 
commodities. 

If you pass the test for material participation you file 
Schedule F and are subject to self-employment tax on 
the income. [I.R.C. §1402. Treas. Reg. §1. 1402(a)- 
4(b)(6) gives six examples] 



Capital Gains Changes 

TRA97 set up three rate groups of assets: 

1 . 28%. Short-term gains and losses, assets held not 
more than 1 2 months; all collectibles (coins, paintings, 
stamps, wine, etc.); long-term capital loss carryovers. 
(Note: Excess depreciation (above straight-line 
amounts) recaptured from the sale of § 1 250 property 
(basically, buildings) is ordinary income, does not 
appear on Schedule D.) 

2. 25% Long-term gains (no losses in this group) from 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



sale of buildings and improvements that result from 
straight-line depreciation (generally, the rest of the 
depreciation you have taken), limited by net §1231 
gain [Technical correction in RRA98 to IRC 
§l(h)(7)(B)]. Section 1231 property is those durable 
assets used in a trade or business (not in inventory, not 
supplies). 

3. 20% All other long term gains and losses, including 
the gain over purchase price from selling a building. 

The 1997 Act also set complicated holding 
periods. RRA98 has simplified matters in several 
areas. 

1. Sales on or after January 1, 1998, of assets held more 
than 12 months qualify for long term capital gains. 

2. The amount of gain at the 25% rate is limited to the 
net §1231 gain. [IRC § 1(h)(7)(b)] Generally, this 
change only becomes a concern during a year when 
you sell some property for less than you paid for it. 
Example: In 1998, Bruce Bullock sells a piece of land 
for $80,000 that he had purchased for $100,000. He 
also sold a building for $80,000 that he purchased for 
$70,000. He had taken $40,000 of straight line 
depreciation on the building. He had no unrecaptured 
§1231 losses from prior years. Bruce also sold some 
mutual fund shares for a gain of $20,000. The basis of 
the building is $30,000 ($70,000 - $40,000). 
Therefore, in 1998 Bruce has: 



Gain on building 
Loss on land 
Net §1231 gain 



$50,000 
(20.000) 
$30,000 



On the building alone, Bruce has $40,000 of gain taxed 
at 25% (the straight-line depreciation) and $10,000 of 
gain taxed at 20%. (Refer to the rate groups listed 
above.) However, because of the loss on sale of his 
land, the amount of gain subject to the 25% rate is only 
$30,000. Note that the gain on sale of the mutual funds 
offsets the loss on the sale of the land and normally 
these would be netted out, since they are in the same 
(20%) rate group, to give a net gain of zero for that 
group. But the limitation described in the example is 
done first. 

3. Netting of gains and losses. Form 4979 and the 
worksheet on page .seven of the instructions for 
Schedule D together perform the desired calculations. 
If you have losses in the 28% or 20% rate group and a 



gain from selling depreciable property (25% group) 
the worksheet will reduce the recapture amount you 

enter on line 25 of Schedule D. Details of the netting 
are as follows: 

( 1 ) Within each group, net out the gains and losses for 
that group. 

(2) Short term losses first reduce short-temi gains, if 
any. 

(3) Any residue from (2) is applied first to reduce long- 
term gains at the 28% rate, then to reduce gains at the 
25% rate then to reduce gains at the 20% rate. 

(4) A net loss from the 28% group (including long- 
term loss carryovers) is applied first to reduce gains at 
the 257o rate , then to reduce gains at the 20% rate. 

(5) A net loss from the 20% group is applied first to 
reduce gains in the 28% rate, then to reduce gains at the 
25% rate. 

Order of computing tax on gains. For taxpayers in 
the 15% bracket, the capital gains rate will be less than 
the amounts given in the rate groups above. Schedule 
D does a masterful job of figuring out the amounts 
subject to the various rates of tax. It performs 
computations by taking income in the following order: 
ordinary income, taxed at 1 5%; gains in the 25% class 
, taxed at 15%; gains in the 28% class, taxed at 15%; 
and gains in the 20% class, taxed at the reduced rate of 
1 0%. Once the 15% bracket has been used up, the rate 
of the asset group is applied to the capital gains. 

Sale of Farm and Principal Residence 

TRA97 and corrections in RRA98 permit much or 
all of the capital gain on the sale of your principal 
residence ($250,000 if single, $500,000 if married 
filing jointly) to be excluded from income if you meet 
ownership and occupancy requirements (generally, to 
have owned and occupied the house in two out of the 
last five years). [IRC §121] Instead of the single 
lifetime exclusion available previously, you can now 
use the exclusion every time you .sell your home. 
Farmers, therefore, have an even bigger incentive to 
declare their house a principal residence and not part of 
the farm. To get the exclusion you must show that 
your hou.se is residential not agricultural. For 
example, use the area around it to graze horses used for 
plea.sure by your children; maintain the area around it 



10 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



as a garden giving scenic enjoyment; report mortgage 
interest and property taxes on Schedule A rather than 
on Schedule F; retain the house and some land for 
some period of time after the sale of the farm. 

Net Operating Losses on the Farming 
Business Now Carried Back Five Years [IRC 

§172(b)(l)(G)] 

RRA98 added a five-year carryback for the net 
operating loss that would result if only income and 
deductions attributable to farming businesses were 
taken into account (i.e., "farming losses", reduced by 
the amount of profit, if any, from other businesses). 
[IRC § 172(b)(1)(G)] "Farming business" means the 
trade or business of farming, including operating a 
nursery or sod farm and raising or harvesting fruit trees 
and ornamental trees. [IRC §263A(e)(4)] 

If you want to make use of the net operating loss 
provisions to lower your taxes, the five-year carryback 
is now the default. If you want to use the regular net 
operating loss provisions you must elect to do so. Such 
election must be made by the due date (including 
extensions) for filing the return for the year with the 
loss. Once made, the election is irrevocable. [IRC 
§172(b)(3)] 

Regular net operating loss provisions have also 
changed. In 1 998 and future years losses can be carried 
back two years (instead of three) and carried forward 
20 years (instead of 1 5). [TRA97; IRC § 1 72(b)( 1 )( A)] . 
Farmers in "Presidentially declared disaster areas" can 
use a three year carryback for disasters but not for 
"fanning losses" (i.e. not for losses incurred in the 
ordinary business), so this is of little use to most 
farmers. If you want to use these regular provisions 
you can elect to use only the carryforward provision. 
The same conditions apply to this election. You must 
make the election before the due date to file your return 
(including extensions) and once made the election is 
irrevocable. 

Net operating loss carryback and carryforward is 
most useful when set against income subject to high 
marginal tax rates. If you have low incomes and low 
marginal tax rates in prior years you may wish to use 
carryforward only. This is a decision that requires 
careful analysis of past years' incomes and formation 
of expectation about future net incomes. 

Form 1045 and its associated Schedules are used 
to make the complex adjustments to itemized 



deductions, to figure the allocation of losses and to 
calculate the amount of the tax reduction. As before, 
net operating losses are allocated chronologically, that 
is, to the earliest eligible year first. 

Massachusetts State Taxes Get Up to Date - 
Almost 

After being frozen at January 1, 1988, 
Massachusetts personal income tax law now follows 
the Internal Revenue Code in effect on January 1, 
1998. Unless they are related to deductions for 
business expenses or one of the special federal tax 
provisions such as Roth and Education IRAs, any 
federal tax law changes that become part of the IRC as 
amended and in effect after January 1, 1998, will not 
be adopted by Massachusetts. 

One place where farmers might be affected is with 
depreciation. If you took different amounts of 
depreciation on a property for federal and State 
purposes, that difference will disappear on your 1998 
returns. Example: The life for single purpose 
agricultural or horticultural buildings placed in service 
after 1989 is 10 years for federal purposes while it 
would remain at the 1988 life of 7 years Massachusetts 
purposes. Possibly amounts on purchased equipment 
taken as expenses (§179 expensing) might have been 
higher for federal than for State purposes. These 
differences would cause the amount of depreciation 
taken on federal returns to differ from that taken on 
State returns. 

Septic Credit Carryover 
Extended to Five Years 

The Massachusetts credit for the replacement or 
repair of failed cesspools or septic systems had been 
amended to extend the carryover for unused credit 
from three to five years. The current annual $1,500 
maximum credit and $6,000 total maximum credit 
remains the same. If you claimed the credit in 1997 you 
have until 2002 to carryover any unused credit. 

Conversion to Roth IRA: 
What Did You Miss? 

If you convert from a traditional IRA to a Roth 
IRA by December 31, 1998, you meet a special rule 
that allows you (but does not require you) to spread the 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



11 



taxable income from the conversion over the next four 
years. This is not as big a deal as some advertising 
implies. You lose little by converting one fourth of the 
planned amount in each of the next four years. Most of 
the advertising by mutual funds or brokers is (or should 
be) directed at employees. Self-employed individuals 
have other possibilities (SEP-IRA and SIMPLE-IRA) 
that remove much of the attraction of the Roth IRA. 

A contribution to a Roth IRA is income after taxes 
have been paid while a contribution to a regular 
(deductible) IRA is before tax income. Both types of 
IRA accumulate earnings tax-free. Distributions from 
a Roth IRA are tax-free, while those from a regular 
IRA are taxable. The key issue appears to be whether 
the tax rate on contributions will be higher, the same or 
lower than the tax rate on distributions. If higher, the 
Roth is an advantage. If lower, it is not. 

Worksheets that do not employ any "smoke-and- 
mirrors" appear to show that conversion of a regular to 
a Roth IRA is advantageous, even when the tax rate 
during retirement is lower. That is, removing funds 
from a regular IRA, paying the tax on these funds 
(which are treated as ordinary income) and depositing 
the funds in a Roth IRA gives greater retirement 
income than not making the conversion. The money to 
pay taxes must come from somewhere, but the result 



occurs even after factoring in the lost earnings on that 
money. 

Why does the conversion "work" even if your tax 
rates fall after you retire? Because it allows you to 
shelter more interest and dividend income from taxes. 
If it is your goal to put a lot of money away for 
retirement, as an employee you are restricted to $2,000 
of earned income each year (and usually less if you 
participate in another retirement plan). A Roth IRA 
conversion lets you increase this. Example: You 
withdraw $10,000 from a regular IRA. If you have 
sufficient other income to put you in the 28% tax 
bracket, the tax on this distribution is $2,800. Without 
any other source of money you only have $7,200 to put 
into a Roth IRA. If in retirement you are subject to a 
28% percent tax rate it turns out that your after-tax 
retirement income is the same whether you converted 
or not. (Worse, the $2,800 is treated as a premature 
withdrawal and incurs a further 10% excise tax 
penalty.) But if you have other money to pay the 
$2,800 tax bill, you are effectively putting that same 
amount into your IRA (in addition to the $2,000 that 
you could put into a new Roth IRA). 



Footnotes: IRC. Internal Revenue Code; T.C., 
Court; Treas. Reg., Treasury Regulations. 



Tax 



^f# %J# •Im mlm •A* 
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12 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



Preliminary Study of IPI\/I Options for 
Peaclies: i\/lajor Fruit-damaging Insects 

Karen I. Hauschild 

Department of Plant & Soil Sciences, University of Massachusetts 

Arthur T\ittle and Daniel R. Cooley 

Department of Microbiology, University of Massachusetts 

Ronald J. Prokopy 

Department of Entomology, University of Massachusetts 



At harvest, the most severe damage on peach fruit 
is caused by true bugs (primarily insects in the group 
Pentatomidae, stink bugs) and Japanese beetles. Fruit 
may show scarring or fresh feeding wounds accompa- 
nied by a gummy ooze. Often this injury is severe 
enough that damaged fruit must be culled or, at the 
very least, downgraded to processing quality. With 
the greatest profitability gained from fresh-quality 
peaches, growers need and want to keep insect-dam- 
aged fruit at the lowest level that is economically and 
environmentally feasible. 

There are three species of stink bugs that are known 
to attack peaches and cause cat-facing injury: the 
brown stink bug (Eiischistus sennis), the dusky stink 
bug [E. nisrigmus), and the green stink bug 
{Acrosternum hilare). These insects are all highly 
mobile, and usually remain in the orchard for only a 
short period of time. Stink bugs reproduce on the trees, 
laying eggs on the lower surface of peach leaves. These 
eggs are easily identified; they are barrel-shaped, shiny, 
and appear in clusters of about seven eggs each. After 
the eggs hatch, the young nymphs move into the or- 
chard groundcover. Nymphs do little feeding on 
peaches. Primary damage is the result of adult feed- 
ing. Numbers of brown and dusky stinkbugs are great- 
est within a month of shuck fall. Green stink bug num- 
bers tend to increase throughout the growing season. 
The most severe damage to peach fruit occurs between 
petal fall and the time when fmits are 0.5-0.75 inch in 
diameter. If fruit that is damaged during this time pe- 
riod fails to abscise, at maturity, it is heavily scarred or 
malformed (injury commonly referred to as "catfac- 
ing"). As the fruits enlarge, damage by stinkbugs is 



less dramatic. Injury results in holes with gummy exu- 
date or dry, corky areas just below the fruit surface. 

The Japanese beetle {Popillia japonica) is a seri- 
ous pest of ornamentals, grapes, and plants in the fam- 
ily Roseaceae. Adult beetles chew on leaves and fruit. 
Leaf damage ranges from minor tissue loss to com- 
plete skeletonization. Fruit damage is restricted to the 
fruit surface (surface damage), but can be extensive 
and contaminated with beetle frass. Damage caused 
by Japanese beetles often attracts other insects or dis- 
ease organisms. Because Japanese beetles tend to 
congregate, damage can occur very quickly and be- 
come quite severe in a short period of time. 

The objective of this study was to determine the 
incidence of damaged caused by these pests under re- 
duced-pesticide regimes. Brown rot incidence from 
the same study was reported [Fruit Notes 62(4)] . 

Materials & Methods 

Until pit hardening in early June, all treatment plots 
received standard calendar-based pesticide applications 
every 7 to 10 days. After pit hardening occurred, four 
different treatment protocols were employed. These 
treatments are outlined in Table 1 . Refer to Fruit Notes 
62(4) for additional information on experimental de- 



Results & Discussion 

For Redhaven peaches (Table 2), the incidence of 
stink bug damage was twice that of Glohaven (Table 
3), while the incidence of Japanese beetle damage was 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



13 



Tabic 1 . Insecticide and fungicide ircalmciiis on 


pcache.s 


after June 10 at the 


University of Massachusetts Horticultural Research Center, Bel 


chertown, MA, 1996 


Treatment 






(rate /lOO gal. dilute spray) 




Date of application 


Full spray 






Imidan 70WP (0.75 lbs.) 




17 June; 2, 14, 25 July 


Captan80WP(l lb.) 




17 June, 2, 14 July 


Captan 80WP (1 lb.) + Benlate 50DF (6 11. oz.) 




25 July, 2 Aug. 


Reduced spray 






Imidan 70WP (0.75 lbs.) 




2, 14 July 


Captan 80WP (I lb.) 




2, 14 July 


Captan 80WP (1 lb.) + Benlate 50DF (6 R. oz.) 




2 Aug. 


Lo\^' spray 






Imidan 70WP (0.75 lbs.) 




2, 14 July 


Captan80WP(Ilb.) 




2 July 


Captan 80WP (1 lb.) + Benlate 50DF (6 n. oz.) 




Aug. 


No spray 






None 




none 


i 



substantially less than that on Glohaven. These 
differences most likely reflect the timing of 
activity of each of these two insect pests rela- 
tive to the timing of fruit development of the 
two cultivars and the last insecticide spray. 

The four treatment regimes resulted in 
similar levels of stink bug damage on Redhaven 
and Glohaven fruit(Tables 2 and 3). Because 
these were 3-tree plots, with different treat- 
ments applied to adjacent trees, it is possible 
that spray drift could account for at least some 
of the lack of effect. Timing of insecticide ap- 
plications could have affected results as well. 

Redhaven fruit under the reduced-spray 
regime had the greatest amount of Japanese 
beetle feeding, and those under the other treat- 
ments were similar (Table 2). Likewise, 
Glohaven fruit under the reduced-spray treat- 
ment had the most damage, but for Glohaven, 
the no-spray treatment had significantly less 
damage (Table 3). It is unclear why these re- 
sults occurred. It is likely, however, that real differ- 
ences did not occur in this experiment. High mean 



Table 2. Insect damage to Redhaven peaches under 
different pesticide treatment schedules. Fruit were 
harvested on August 15 and 21. Each treatment 
included three trees in each of three replications. For 
assessment, 100 peaches were harvested from each 
tree. '- 







Stink bug 


Japanese beetle 


Trcalmcnt 




damage (%) 


damage (%) 


IhiII s|ii"ay 




28 a 


2b 


Reduced spi 


ay 


31 a 


6a 


Low spray 




29 a 


4b 


No spray 




22 a 


3b 



'Means within columns not followed by the same 
letter are significant at odds of 15:1. 



values were likely the result of very localized infesta- 
tions of Japanese beetles. 



14 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



Tabic 3. Insect damiige Id Glohavcn peaches under 
differenl pesticide Ireatmenl schedules Fruil were 
harvested on September 3. Each treatment included 
three trees in each of lour replications. For 
assessment, 100 peaches were harvested from each 
tree. ' 



Treatment 



Slink hug 
damage (%) 



Japanese beetle 
damage (%) 



Full spray 
Reduced spray 
Low spray 
No spray 



9a 
12a 
12a 
12a 



23 b 

31 a 

16 be 

9c 



^Means within columns not followed by the same 
letter are significant at odds of 15:1. 



Clearly Ihiscxpcriincnl shuuld be repeated, 
perhaps with closer attention paid to timing of 
insecticides. Weekly scouting of plots would 
help to determine more accurately when each 
insect pest is present, and whether timing of 
insecticide applications coincides with the tim- 
ing required for fungicide applications. Closer 
attention to pest status would also help to ex- 
plain how these pests enter and move within 
the orchard. 

It is obvious from this data, however, that 
both stink bugs and Japanese beetles can have 
a substantial effect on fruit quality at harvest. 
Better timing of insecticide treatments and al- 
ternative pesticides or methods of control could 
impact results in another year. 



«1^ %t^ m^A %!• %!• 
rj* #^ ry% rj% rj^ 



Fruit Notes, Volume 63 (Number 2), Spring, 1998 



15 




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, IMA 01002 



1 

SERIAL SECTION 

UNIV OF MASSACHUSETTS LIBRARY 

AMHERST MA 01003 



Account No. 2-22914 



vJorr 



Fruit Notes 

Prepared by the Department of Plant & Soil Sciences. 

UMass Extension, U. S. Department of Agriculture, and Massachusetts Counties Cooperating. 

Editors: Wesley R. Autio and William J. Bramlage 




blume 63, Number 3 
SUMMER ISSUE, 1998 

Table of Contents 



An Easy and Reliable Procedure for Predicting Scald and 
DPA Requirement for New England Delicious Apples 

Commercial-orchard Trial of Unbaited Traps 
for Monitoring Plum Curculio: 1998 Results 

Comparison of Six Different Types of Unbaited Traps 
for Monitoring Plum Curculios in Orchards 

Two Odor Compounds Hold Promise for Increasing 
Trap Effectiveness for Plum Curculio 



Fruit Notes 



Publication Information: 

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

The costs of subscriptions to Fruit Notes are $ 1 0.00 for United States 
addresses and $ 1 2.00 for foreign addresses. Each one-year subscription 
begins January 1 and ends December 3 1 . Some back issues are available 
for $3.00 (United States addresses) and $3.50 (foreign addresses). Pay- 
ments 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 



UMASS 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 no warranty or guarantee of any kind, expres.sed or implied, 
concerning the use of these products. USER ASSUMES ALL RISKS FOR PERSONAL 
INJURY OR PROPERTY DAMAGE. 



Issued hv UMiiss Extension, Jclin (ierhcr. Direclor, in liirllwranie oj the acts of M(iy S tutd June ^0. 1 914. 
Utvtass Extension t'ffers equal njifun lunilv in piiii^itiiiis and eiiiplnynietit 



An Easy and Reliable Procedure for 
Predicting Scald and DPA Requirement 
for New England Delicious Apples 

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



The processes which control scald susceptibility 
and development have been, and are being, studied by 
many researchers. While the exact causes of scald are 
not known, it has been observed that a) within a 
cultivar, late harvested fruit scalds less than early 
harvested fruit, b) other things being equal, the riper 
the fruit at harvest, the less they will scald, c) scald 
susceptibility varies from year to year among fruit, 
even from a given tree, and d) year to year variation is 
(at least partly) a function of weather. Cool, sunny 
weather favors scald reduction, while hot weather may 
increase scald susceptibility. 

We have been studying the effects of weather on 
scald variability, both at the University of Massachu- 
setts Horticultural Research Center (HRC) and at other 
New England locations in relation to effects recorded 
at various locations world-wide. Here we will report 
on recent findings from the New England studies. Our 
sites were in Ashfield, Belchertown (HRC), Shelbume, 
Warren, and Wilbraham, MA, Storrs, CT, Putney, VT, 
Durham, NH, and Monmouth ME. First, it must be 
recognized that many of the factors purported to 
influence scald are related to one another. For 
example, as the harvest season progresses, the fruit 
ripen, temperature falls, and the days become shorter. 
However, these factors relate somewhat differently to 
one another in different years, and in different 
locations. Our hope was that if we collected data for 
many years at the HRC, we could identify some of the 
specific factors influencing scald susceptibility, and 
then develop a workable general relationship of 
preharvest factors to scald susceptibility. 

The factors we have concentrated on are the 
following: 1) preharvest cool temperature as the 
number of days the apples are subjected to sub-50"F 
weather between August 1" and harvest; 2) a 
qualitative measure (sunny, partly cloudy, cloudy) of 



light to which fruit are subjected during the week prior 
to harvest; 3) fruit maturity at harvest as measured by 
a starch/iodine test, and 4) harvest date. Because we 
have been working primarily with Delicious, which 
are not harvested before late September, we did not 
experience enough hot (over 80"F) weather near 
harvest to evaluate that factor, even though we know it 
could be important. We also have not included a light 
factor in the reported equations because light measures 
were only available for the HRC. 

Development of Prediction Equations 

Between 1988 and 1993, we harvested 213 one- 
bushel samples of Delicious from HRC, stored them 
20-25 weeks in 32"F air, and then removed the fruit to 
room temperature for a week before rating them for 
scald. Scald rating consisted of examining each apple 
in a box and recording the percent of apples developing 
scald in that box. A sample was considered very scald- 
susceptible if more than 60% of fruit in the box 
developed scald, and was considered scald-resistant if 
fewer than 20% of the fruit developed scald. It should 
be noted that any sign of scald was recorded, and some 
fruit in this latter category would not have been 
downgraded. The following equations, reported in 
Fruit Notes 61(4) were generated: 

Equation 1: If [8.36 - 0.320(harvest date as 
number of days after 8/31) + 0.0546(number of 
preharvest days < 50"F) - 0.0550(harvest starch 
score)] > 0, then fruit are very scald-susceptible. 

Equation 2: If [-11.8 + 0.414(harvest date as 
number of days after 8/31) - 0.0298(number of 
preharvest days < 50"F) - 0.708(harvest starch 
score)] > 0, then fruit are very scald-resistant. 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



If a sample fits neither of these categories, it is 
considered to be of intermediate scald susceptibility. 
Please note: There was a typographic error in one 
equation in Fruit Notes 61(4). Those that we present 
here are the correct equations. 

The numbers you get from these calculations are 
called Indices. These Indices were tested in 1995, 
1996, and 1997 a) for their ability to accurately place 
samples in the correct scald category and b) to see if 
they could be used as guides for application of the 
scald inhibitor, diphenylamine (DPA). We also are 
interested in relating the scald potential of controlled 
atmosphere (CA)-stored fruit to the scald Indices. In 
1 996 and 1 997, we stored fruit from the HRC in C A, as 
well as in air storage. Scald symptoms on the CA fruit 
were roughly parallel to symptoms on air stored fruit, 
but affected a significantly higher percent of the fruit. 
It is possible that this is because CA fruit were stored 
for 28 to 29 weeks, while air-stored fruit were kept for 
25 weeks. In CA, the specific atmosphere should 
influence scald potential. Our storage atmosphere was 
2.8% 0„ <2% CO,. Lower oxygen concentrations 
ought to reduce scald, but we do not yet have adequate 



data to address specific questions regarding use of the 
scald Indices to determine DPA requirements for CA- 
stored fruit. 

Ability of Equations to Predict Scald 

Figure 1 shows how well the 1995, 1996. and 1997 
samples fit the equations developed using the pre- 1 995 
data. These samples included fruit from Storrs, CT, 
Putney, VT, Durham, NH, and Monmouth, ME, as 
well as the MA locations shown in Figure 2. In each 
category, observed scald was only slightly different 
from predicted scald, indicating successful application 
of the equations to estimate scald potential at the time 
of fruit harvest. 

Very Scald-susceptible Fruit 

Figure 2 shows the most scald susceptible samples 
from Massachusetts, which were those from the first 
harvest at each location. In all locations and years 
scald did develop on more than 60% of these fruit. 
However, responses to DPA varied by location. The 



n Fruit Predicted to Scald ■ Observed as Predicted 



80% 



■S 60% 

E 
<o 



,2 40% 



c 

0) 

u 

o 20% 

Q. 



0% 





> 60% 



<60% <20% 

Number of Fruit Expected to Scald 



>20% 



Figure 1. Summary of results of scald forecasts: 237 samples, 9 orchards in Five states, 1995, 1996, 1997. Fruit 
developing any scald-like. 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



100 






nj 
u 
(/) 

< c 

^1 



5 

3 to 

U. 



c 

0) 

u 



a> 
a. 



DNo DP A DSOO ppm DP A 11000 ppm DP A 12000 ppm DP A 




Figure 2. Effects of DPA when more than 60% of fruit were predicted to scald. Percent of fruit showing any 
scald-like symptoms. 



highly scald susceptible fruit from the Warren MA site 
responded to 500 or 1000 ppm DPA to a much greater 
degree than did the corresponding fruit from other 
sites. (The only statistical comparison which could be 
made was with HRC and there the difference was 
significant at odds of 1:100). Yet overall, 2000 ppm 
DPA would have to be recommended for confidence 
that scald would be controlled in these highly scald 
susceptible fruit. Note that all the fruit samples 
represented in Figure 2 were harvested before 24 
September, and Delicious are not normally harvested 
that early in New England. Results for samples 
harvested during the commercial harvest period will 
be represented below in Figure 3 and Tables 1 and 2. 

Intermediately Scald-susceptible Fruit 

When we moved on to consideration of the next 
category of fniit, those of intermediate scald- 



susceptibility, we began looking closely at scald 
severity, as well as whether any scald-like symptoms 
were evident. Most of the samples of "very scald- 
susceptible" and "intermediately scald-susceptible" 
included fruit displaying scald of varying degrees of 
severity. Scald would clearly render some of the fruit 
unsaleable in the fresh market. Other fruit, however, 
displayed scald, or scald-like symptoms, which would 
not be noticeable to the casual observer, and would not 
likely downgrade the fruit. The "very scald- 
susceptible" fruit tended to have enough severe scald 
that there was no question but that 2000 ppm DPA was 
needed if the fruit were to be stored for 25 weeks. In 
the fruit of intermediate scald susceptibility (or less), 
there often were few fruit with severe scald. In some 
cases we had difficulty determining if a given apple 
did or did not have scald. Therefore, we used a rating 
system which separated fruit showing any discolora- 
tion that might possibly be scald, from fruit with more 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



D No DP A, Any Scald 
DSOO ppm DP A, Any Scald 



I No DP A, Distinct Scald 
1500 ppm DP A, Distinct Scald 




HRC 1996 HRC 1997 Warren 1996 Warren 1997 Shelb. 1997 

Figure 3. Effects of 500 ppm DPA when 20-60% of fruit were predicted to scald (Intermediate category). 



D Any Scald from Storage D Any Scald after 1 Week ■"Distinct Scald" after 1 Week 




Figure 4. Development of scald on 'Delicious' apples during one week at room temperature. All DPA 
treatments are included, and vary by year and location. These data do not relate to treatment; only to develop- 
ment of scald at room temperature. 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



Table 1. Percent of fruit on which any scald-hkc symptoms occurred when fewer than 20% ol fruit had been 
predicted to scald. 



Percent of fruit with any scaid-hke symptoms if 
index is: 



Location 



Harvest year 



Number of 
samples 



0-1 



1-3 



>3 



HRC 


1995 


15 


43 


9 


11 




1996 


20 


/ 


23 


11 




1997 


13 


34 


2 





Ashfield 


1996 


10 


15 


12>' 


2 


Wilbraham 


1995 


10 


- 


10 


10 


Warren 


1996 


10 


24 


13 


_ 




1997 


10 


- 


7 


- 


Shelbume 


1997 


10 


- 


18 


4 


Storrs, CT 


1995 


5 


- 


- 





Putney, VT 


1996 


5 


26 


34" 


- 


Durham, NH 


1996 


12 


31 


2 


- 


Monmouth, ME 


1996 


10 


- 


23 


- 


Overall 




130 


30 


12 


6 


' A "-" indicates that 


no samples fell into this 


category. 








" Sample consists of 


Dniy one box. 











distinct external browning which would clearly reduce 
the grade of the fruit. In Figure 3, the term "distinct 
scald" is used. This scald was not always severely 
disfiguring, but it always was clearly noticeable. The 
term, "Any Scald" is used in Figure 3 (and Figure 4) to 
denote fruit which showed any scald-like external 
browning. We did observe differences in the 
appearance of scald on fruit from different sites. Scald 
on the HRC Redspur in particular was difficult to rate, 
because the early harvested fruit tended to have a 
brownish cast which was not necessarily scald, but did 
not occur when the higher concentrations of DPA were 
used; this brownish cast did not appear on fruit from 
the latest harvests. In contrast, the Sturdeespur from 
Warren showed scald very clearly if it was present at 
all. The appearance of scald was also variable among 
the different striped strains of Delicious we harvested 
in Ashfield in 1996. In fruit from some trees, the scald 
stood out, while in fruit from others, scald blended 



with the fruits' coloring, making it less noticeable. 

Figure 3 shows the effects of 500 ppm DPA on 
fruit predicted to be of intermediate scald susceptibil- 
ity. These fruit all were harvested from September 30 
to October 3, when commercial Delicious harvest is 
expected to begin. From to 3% of the 500 ppm DPA- 
treated fruit shown in Figure 3 clearly displayed scald. 
It should be noted for those who find 3% scald too 
much, that the 1996 HRC Delicious, which show 3% 
scald in Figure 3, also showed 3% scald following 
storage when 2000 ppm DPA was applied. Overall, 
500 ppm DPA provided adequate .scald control; use of 
1 000 to 2000 ppm DPA was not any more beneficial 
and constituted overu.se of the chemical on these 
intermediately susceptible fruit. 

Fruit With Low Scald Susceptibility 

The second equation presented earlier in this 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



Tabic 2. Percent ol 


Iruit on which dislinc 


t scald ; 


>vmpl()ins 


occurred when 


lower than 


207, 


ol Iruii had been 


predicted to 


scald. 


































'erceni 


ol Iruit 


with distinct 


seal 


ll ll IIH 


ex is: 








Nu 


mbcr 
















Location 




Harvest date 


s 


implcs 




0-1 




1-3 






>3 


HRC 




10/8/96 
10/15/96 
10/2/97 
10/9/97 
10/14/97 




10 

10 

3 

5 

5 




IB 




18 









6 



Ashfield 




10/3/96 
10/14/96 




5 
5 




3 




1 









Warren 




9/30/96 
10/7/96 
10/6/97 
10/16/97 




2 
8 
5 
5 




17 




1 

2 









Shelburne 




10/8/97 
10/15/97 




5 
5 




- 




11 






3 


Overall 








73 




13 




7 






3 


' A "-" indicates that 


no samples fell 


into this category. 















report identifies fmit of low scald susceptibility. This 
categoi^ should represent fnait with little or no need 
for DPA treatment. Identifying these fruit is of 
particular interest because 1 ) scald control treatment is 
expensive and inconvenient to apply, and 2) the 
materials used are not acceptable to an increasing 
number of markets. Clearly, if 20% of fruit in a lot 
develop scald, this is unacceptable. However, when 
we attempted to generate equations for forecasting 
small amounts, for example, less than 10% .scald, we 
were unsuccessful; there was simply too much 
variation in scald development in the vicinity of 10%. 
We therefore developed the equation to predict under 
20% scald because it produced consistent results. If 
the Index for the "scald resistant" equation (Equation 
2) is greater than zero for a given day, location, and 
starch score, then fewer than 207c of fruit harvested on 
that day will be predicted to scald after 25 weeks of 
storage. In addition, the higher the Index, the greater 
the likelihood that fewerthan 207p of fmit will scald. It 
also follows that the higher the Index, the less scald 
one would expect. Tables I and 2 show how many fruit 



developed any scald-like browning (Table 1) and how 
many developed "distinct scald" (Table 2). As the 
Index increased, the amount of scald did indeed 
decrease. There was some variability among orchards 
and years, but the trend was there. What this means is 
that an individual could base scald control measures on 
personal experience about how much scald had 
developed on fmit from this site in previous years, and 
on how much risk the grower was willing to accept, 
using the tables shown below as a guide. If the Index 
for Equation 2 is greater than zero, low susceptibility 
exists. As the number becomes increasingly greater 
than zero, the risk of scald becomes progressively 
smaller. 

A Simple Procedure for Using (he 
Prediction Equations 

The equations presented earlier in this article can 
be intimidating. However, they can be rearranged to 
produce an easy-to-use system for tracking scald 
susceptibility during the harvest .season. 



Fruit Notes, Vokime 63 (Number 3), Summer, 1998 



Equation 1 ; Ti 


) idenlify highly scald-sustcplihic Iruil (more than 60% likely to scald): 




8.36 










- 




In Seplember:[day ol month] x 0.320, or 
In Oclober:[30 + day of month] x 0.320 








+ 




(Number of times (overnights) the 
temperature was below 50"F] x 0.0546 








- 




[Starch Score (measured on harvest 
date) of representative fruit] x 0.0550 














= INDEX 




If greater than 0, then more than 60% 
of fruit likely to scald 









Equation 2: To identify scald resistant fruit (fewer than 20% likely to scald): 




-11.8 










+ 




In September: [day of month] x 0.414, or 
In October:[30 + day of month] x 0.414 








- 




[Number of times (overnights) the 
temperature was below 50"F] x 0.0298 








- 




[Starch Score (measured on harvest 
date) of representative fruit] x 0.708 














= INDEX 




If greater than 0, then fewer than 20% 
of fruit likely to scald 









Example: Delicious were harvested on October 1, the 
temperature had gone below 50"F on 7 nights since 
August 1, and the starch score at harvest was 2.2. 

Using Equal ion I : 

8.36 - 3 1 (0.320) + 7(0.0546) - 2.2(0.0550) = Index I 

so. Index 1 =-1.30 

Since the Index is less than zero, less than 60% of the 
fruit are predicted to scald after storage if no DPA is 
applied. 



Using Equation 2: 

-1 1.8 + 31(0.414) - 7(0.0298) - 2.2(0.708) = Index 2 

so. Index 2 = -0.73 

Since this Index also is less than zero, then more than 
20% of fruit are predicted to scald. Therefore, if these 
fruit are stored in air at 32"F for 20-25 weeks, between 
20% and 60% of the fruit can be expected to scald if no 
DPA is applied. This scald can be controlled by 
application of 500 ppm DPA, as seen in Figure 3. 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



Post-Storage Scald Development 

One of the concerns about scald is that while it 
may not appear on fruit on removal from storage or 
when packed, it may appear later, before fruit are 
consumed. We had not intended to address this issue, 
but we would like to report here that we did not see a 
great deal of scald developing during the week the fruit 
were kept at room temperature. In 1996 and 1997, we 
inspected some of the fruit at the time of removal from 
storage, as well as after 7 days at room temperature. 
Figure 4 shows that on air-stored Delicious, this post- 
storage increase in scald was not significant. Note that 
sometimes more scald was discernible at removal from 
storage than after a week at room temperature. This is 
an indication of the difficulty we sometimes had in 
determining if fruit discoloration was or was not scald. 
It should be made clear that not all cultivars are like 
Delicious in this regard. For example, we have 
observed repeatedly that Cortland may show little or 
no sign of scald at removal from storage, but after 7 
days at room temperature, much scald is present. 

Conclusions 

We conclude from this research that forecasting 
scald susceptibility on air-stored New England 
Delicious is feasible, and we believe that use of these 
prediction models can lead to more efficient use of 
DPA. Results of 3 years of tests of the models 
developed from 6 previous years' data indicate that 
using a calendar, a min-max thermometer, and a starch 
test for maturity, one can use these equations to 
effectively predict high, intermediate, or low scald 
susceptibility of Delicious apples harvested at a given 



site on a given day anywhere in New England. 
Furthermore, the equations predict the need for DPA: 
highly susceptible fruit require 2000 ppm, intermedi- 
ately susceptible fruit require only 500 ppm, and low- 
susceptibility fruit, particularly those with an Index 
greater than 1 in Equation 2, have no need for DPA 
treatment. We offer a system for determining which 
fruit need 2000 ppm DPA, which will be protected by 
500 ppm, and which may be stored without DPA 
treatment, and with a minimum of concern for post- 
storage scald development on air-stored fruit. As 
demonstrated by the data in Tables 1 and 2, it is 
possible to choose an Index higher than zero in 
Equation 2 as a demarcation between groups of fruit 
which receive 500 ppm DPA and those which receive 
none. This can be especially useful if experience has 
shown that the fruit from particular trees are especially 
scald susceptible, and allows flexibility in determining 
at what point to stop applying DPA. 

Acknowledgments 

The authors would like to thank the following 
people for their assistance in selection and provision of 
fruit and preharvest information for developing and 
testing scald prediction models: Dana Clark, Evan 
Darrow, David Kollas, William G. Lord, Wayne Rice, 
James Schupp, Joe Sincuk, Tim Smith, and Mark and 
Bob Tuttle. Technical assistance by Irene Clark and 
Laura Lee Jones is much appreciated. We would also 
like to thank the Massachusetts Fruit Growers' 
Association, the New England Tree Fruit Growers 
Research Committee, and the Washington Tree Fruit 
Research Commission for their financial support of 
this research. 



vl^ vL* vL* vt» *J> 

^Y* <p» <p» •x* *T* 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



Commercial-orchard Trial of Unbaited 
Traps for Monitoring Plum Curculio: 
1998 Results 



Starker Wright, Stephen Lavallee, and Ronald Prokopy 
Department of Entomology, University of Massachusetts 



For the past 3 years, we have performed field and 
laboratory studies aimed at developing an effective trap 
for monitoring plum curculio (PC) in commercial or- 
chards. Our goal in trap development is to establish a 
system whereby growers can predict the need for and 
timing of sprays. 

In 1996, we evaluated unbaited black pyramid traps 
in small orchard blocks in Belchertown, MA, Conway, 



MA, and South Deerfield, MA. Our principal finding 
in this study was that unbaited pyramid traps are inef- 
fective in warm weather. When the temperature rises 
above 20"C (when most PC injury occurs), PCs enter 
trees largely by flying directly into the tree canopy, 
bypassing the tree trunks and trunk-associated pyra- 
mid traps. 

In 1 997, black pyramid traps were evaluated at three 



(a) 



(b) 



48 inches 




A 



12 inches 




<- 



^ 



-> 



24 inches 



3 inches 



Figure 1 . Trap designs used in the 1 998 field (rial: (a) unbaited trunk-mimicking pyramid trap, placed adjacent to 
the tree trunk and (b) unbaited tvvig-mimicking cylinder trap, positioned wiihiii ihe tree canopy and kept m a 
vertical position by a clipped upright twig. 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



Tabic 1 Relationship between numbers of plum curculio adults captured by unbaited pyramid and twig-mimic 
traps and percent fruit showing injury by plum curculio across all 16 replicates of each tree size treatment m 
commercial orchards in 1998. 



Number of adults captured 
per sampling period 



Tree size 



Sampling period 



Pyramid 



Twig mimic 



Cumulative fruit 
injury (%) 



Small 


Before I'' spray 


0.10 


0.05 


0.1 




Between 1 "* and 2"'' spray 


0.06 


0.09 


1.0 




Between 2"^ and 3"* spray 


0.03 


0.02 


2.2 




After y' spray 


0.00 


0.00 


3.5 


Medium 


Before 1 " spray 


0.14 


0.10 


0.1 




Between i " and 2"'' spray 


0.18 


0.00 


0.4 




Between 2"^ and 3"* spray 


0.02 


0.00 


0.7 




After 3"* spray 


0.00 


0.00 


0.5 


Large 


Before 1 " spray 


0.19 


0.00 


0.1 




Between T and 2"'' spray 


0.12 


0.09 


0.6 




Between 2"'' and 3"" spray 


0.00 


0.00 


0.7 




After 3"' spray 


0.00 


0.00 


0.8 


1 



positions in 48 blocks of trees in commercial orchards. 
In each block, one trap was placed immediately adja- 
cent to the tiTjnk of a perimeter tree, one trap was 
placed at the midway point between the perimeter tree 
and the first interior tree, and one trap was placed at 
the margin of the nearest woods. Data from this study 
extended our 1996 findings. Irrespective of trap posi- 
tion, captures of PC in unbaited pyramid traps did not 
reflect accurately the need for or proper timing of in- 
secticide spray. A second (preliminary) study was 
conducted m 1 997 intended to develop a trap to moni- 
tor PC abundance and activity within tree canopies. 
From this work, we developed a twig-mnnicking black 
cylinder trap as an alternative to trunk-mimicking black 
pyramid traps. 

In 1998, we repeated and expanded our trial of 
trap types in the same 48 commercial orchard blocks 
used in 1997. We compared the performance of black 
pyramid trunk traps with black cylinder canopy traps 
as indicators of the potential for PC injury. 



Materials & Methods 

As in 1997, traps were placed in six blocks of trees 
in each of eight commercial orchards. All blocks con- 
tained 49 trees (seven rows of seven trees each) of 
mixed cultivars. Of the six blocks in each orchard, two 
were considered high tree density (M.9 rootstock), two 
medium tree density (M.26 rootstock), and two low 
tree density (M.7 rootstock). 

Prior to bloom, we placed two unbaited black pyra- 
mid traps in each of the 48 blocks, each trap adjacent 
to the trunk of a perimeter tree (the most effective 
postion for traps of this type). We also placed two 
unbaited black hollow cylindrical (3 inches diameter x 
12 inches height) twig-mimic traps in perimeter trees 
of each block, kept in a vertical position within the 
canopy by a clipped twig (Figure I ). In early May 
1998, when all traps were placed, we knew of no at- 
tractive odor which could be used in conjunction with 
these traps (sec study of odors attractive to PC, this 



10 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 




Prior to 1st 1st to 2nd 2ncl to 3rd 

Insecticide Application 



After 3rd 



D Pyramid 
□ Cylinder 
■ % Injury 



Figure 2. Captures of plum curculios per trap for two unbailed trap types and percent fruit injured by plum curculio 
before the first insecticide application, between the first and second applications, between the second and third 



issue). 

Evei7 3-4 days from petal fall until five weeks af- 
terward (the peiiod of fruit susceptibility to PC injury), 
we examined 15 fruit on each of the seven perimeter 
trees of each block. The number of PC egglaying scars 
was recorded, and scarred fruit were allowed to re- 
main on the tree. At each sample date, captures of PC 
were recorded for each trap, and all captured PCs were 
removed from traps and returned to the laboratory. All 
blocks were treated according to the growers' stan- 
dard orchard management practices, receiving two to 
three applications of Guthion or Imidan at 9- to 14-day 
intervals beginning at petal fall. 

Results 

We combined data for the two blocks of each plant- 
ing density for each orchard and categorized fmit in- 
jury and trap capture data according to spray interval. 
The data (Table 1, Figure 2) show that PC egglaying 
injury was very light in all blocks prior to the first in- 
secticide application. Injury to fruit increa.sed sharply 
between the first and second spray, and increased fur- 
ther between the second and third spray. Interestingly, 
PC damage to fruit subsided in most blocks after the 



third spray, but in a few blocks of high density trees, 
there was a flurry of PC egglaying activity in mid-June, 
after the final spray. 

Captures of PCs by unbaited black pyramid traps 
were greatest prior to the first insecticide application, 
decreased moderately between the first and second 
spray, and decreased substantially after the second 
spray (Table I, Figure 2). In fact, in several blocks 
which continued to accumulate substantial PC damage 
after the second insecticide application, not a single PC 
was captured during this interval by unbaited pyramid 
traps. A similar trend occurred for captures within the 
tree canopies by unbaited black cylinder traps (Table 
I , Figure 2). 

Conclusions 

Results of the 1998 field trial of unbaited PC traps 
confirm our findings of 1 996 and 1 997. For commer- 
cial use, captures of PC in unbaited trunk-mimic or twig- 
mimic traps are not accurate indicators of the need for 
or timing of insecticide applications. If development of 
traps for other species related to PC (such as cotton 
boll weevil and sugar cane weevil) can be used as a 
guide, then the most effective trap for PCs should be 



Fruit Notes, Volume 63 (Number 3), Sui 



1998 



11 



baited with a combination of attractive pheromone and 
host odor (neither of which was available at the start 
of the 1998 season). For 1999, we intend to maximize 
the visual attractiveness of traps, and incorporate use 
of attractive odor lures. 



Acknowledgments 

This work was supported by State/Federal IPM 
Funds, the New England Tree Fruit Growers Research 
Committtee and SARE Grant #97 LNE 97-90 (USDA 
96-COOP- 1-2700). We are grateful to the eight grow- 
ers that participated in this study: Bill Broderick, Dana 
Clark, Dave Chandler, Dave Cheney, Dave Shearer, 
Joe Sincuk, Tim Smith and Mo Tougas. 



vL* vL* vl* »X* vj> 

•T* -T* •?• -T* -T* 

Comparison of Six Different Types of 
Unbaited Traps for Monitoring Plum 
Curculios in Orchards 



Ronald Prokopy, Shawn Mclntire, Jonathan Black, Max Prokopy, 

and Tracy Leskey 

Department of Entomology, University of Massachusetts 



We can conceive of at least four approaches to 
monitoring entry of plum curculio (PC) adults into or- 
chards and orchard trees that might be useful in pre- 
dicting need and time to spray for PC control. These 
approaches are: (1) monitoring flights of PCs exiting 
from overwintering sites in areas bordering orchards, 
(2) monitoring flights of overwintering PCs into orchard 
trees, (3) monitoring PCs entering orchard trees via 
climbing tree trunks, and (4) monitoring PCs present in 
orchard tree canopies. In 1998, we evaluated each of 
these four approaches using unbaited traps placed near 
or in four small blocks of apple trees. 

Materials & Methods 

Two of the four blocks of trees (one at the Univer- 
sity of Massachusetts Horticultural Research Center 
and one in Deerfield, MA) received no insecticide to 
control PC. Each of the other two blocks one at the 



Horticultural Research Center and one in Conway, MA) 
received two sprays of Imidan: one at petal fall and the 
other two weeks later. All trees were on either M.7 or 
M.26 rootstock. 

To monitor exit flights of PCs from overwintering 
sites, we positioned unbaited Tangletrap-coated clear 
Plexiglas traps (2 feet by 2 feet), intended to represent 
empty space, 6 feet from edges of foliage of woods 
that bordered each block. Each of the four traps per 
block was fastened vertically to a wooden pole. The 
center of each trap was 3 feet above ground. The 
sticky-coated side faced the woods. 

To monitor flights of overwintered PCs into orchard 
trees, we positioned three different types of unbaited 
Tangletrap-coated traps 1 8 inches away from edges of 
canopies of orchard trees and facing woods. The three 
trap types were: a 2 foot by 2 foot square of clear 
Plexiglas, a 2 foot by 2 foot square of plywood painted 
green to mimic tree foliage, and a 1 foot by 4 foot tall 



12 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



Tabic I, Numbers ol plum cuaulios captured by each type ol Irap m blocks ol unsprayed and sprayed apple 
trees May I- June 19, 199X 



Trap type 



Number ol replicates 



Unsprayed Sprayed 



Number ol curculios per trap* 



Unsprayed 



Sprayed 



Sticky clear traps at edge of woods 
Sticky clear traps at edge ot apple trees 
Sticky green traps at edge of apple trees 
Sticky black traps at edge of apple trees 
Black pyramid traps at apple tree trunks 
Black cylinder traps in apple tree canopies 



8 


8 


0.5 c 


1.6 a 


8 


8 


2.6 b 


1.0 a 


8 


8 


1.9 b 


0.8 a 


8 


8 


0.3 c 


0.4 a 


16 


16 


26.3 a 


1.5 a 


16 


16 


2.2 b 


0.5 a 



Numbers in the same column followed by a different letter are significantly different at odds of 19:1. 



rectangle of plywood painted black to mimic a tree 
trunk. Each trap was attached vertically to a wooden 
pole, with trap center 3 feet above ground. The sticky- 
coated side faced the woods. Each block contained 
four traps of each type, arranged so that traps alter- 
nated in type. 

To monitor PCs entering orchard trees by climbing 
tree trunks, we placed one unbaited black pyramid 
trunk-mimicking trap (described in the preceding ar- 
ticle) next to the trunk of each of eight perimeter apple 
trees bordering woods in each block. 

To monitor PCs present in orchard tree canopies, 
we placed one unbaited hollow black cylinder twig-mim- 
icking trap (described in the preceding article) in the 
canopy of each of the eight other perimeter apple trees 
(not the same trees having pyramid traps) bordering 
woods in each block. The black cylinder traps were 
maintained in vertical position by placing each one over 
a clipped vertical branchlet about mid-way between 
the edge and center of the tree canopy and at mid- 
height of the canopy. 

All traps were emplaced during the pink stage of 
apple bud development and were monitored twice 
weekly for eight weeks for captured PCs. On each 
monitoring day, beginning at petal fall, 1 2 fruit on each 
of 12 perimeter trees per block were examined for 
evidence of PC damage. Damaged fruit were allowed 
to remain on the tree. 



Results 

In the unsprayed blocks of apple trees, significantly 
more PCs (at least 10 times more) were captured by 
black pyramid traps next to apple tree trunks than by 
any other type of trap (Table 1 ). Sticky clear traps and 
sticky green traps at edges of apple tree canopies, along 
with black cylinder traps in apple tree canopies, cap- 
tured about the same number of PCs and significantly 
more than the sticky clear traps at edges of the woods 
or sticky black traps at edges of apple tree canopies 
(Table I ). Despite the large number of PCs captured 
by the pyramid traps, captures by these traps were not 
useful in predicting occurrence of PC injury to fruit. 
Thus, increases in captures by sticky clear traps and 
sticky green traps at edges of apple tree canopies, but 
not increases in captures by any other types of traps, 
were positively correlated with increases in fmit dain- 
age caused by PCs during the monitoring period. 

In the sprayed blocks of apple trees, there were no 
significant differences among any of the trap types in 
numbers of PCs captured, although sticky clear traps 
at edges of woods and black pyramid traps next to apple 
tree trunks captured the most PCs numerically, and 
sticky black traps at edges of apple tree canopies and 
black cylinder traps in apple tree canopies captured 
the fewest PCs numerically (Table I). Increases in 
captures by any of the trap types did not correlate sig- 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



nificantly with increases in fruit damage caused by PCs 
during the monitoring period. 

Compared to captures of PCs by traps in unsprayed 
blocks, captures in sprayed blocks were ( 1 ) just as great 
for PCs caught by sticky clear traps at edges of woods 
(this is an expected finding because orchard sprays 
should not interfere with emigration of PCs from woods), 
(2) fewer by an average of about 50% for PCs caught 
by all three types of sticky traps (combined) at edges 
of apple tree canopies, (3) fewer by about 80% for 
PCs caught by black cylinder traps in apple tree cano- 
pies, and (4) fewer by about 95% for PCs caught by 
black pyramid traps at apple tree trunks. We do not 
know why orchard sprays apparently interfered more 
with captures of PCs by pyramid traps at tree trunks 
than captures by cylinder traps in tree canopies. 



apple tree canopies better coincided with periods of 
increase in fruit injury than did periods of increase in 
captures of PCs by black pyramid traps at tree trunks. 
Disappointingly, in the sprayed blocks, in no case did 
periods of increase in captures of PCs by any of the 
trap types tested in 1 998 correlate positively with peri- 
ods of increase in fruit injury. 

We believe that a more user-friendly form of a 
sticky trap placed at the edge of an apple tree canopy 
to capture PCs flying into apple trees and/or a modi- 
fied form of a cylinder trap placed in an apple tree to 
capture PCs active within the canopy hold the most 
promise as effective monitoring devices. We further 
believe that neither of these trap types can succeed in 
monitoring accurately the presence of PCs in sprayed 
orchards unless they are baited with attractive odor. 



Conclusions 



Acknowledgments 



The findings from these studies in unsprayed blocks 
of apple trees in 1998 are similar to findings reported in 
Fruit Notes 63(1) on studies in an unsprayed block of 
apple trees in 1997. In both studies, periods of increase 
in captures of PCs by sticky clear traps at edges of 



This work was supported by USDA Hatch funds 
and the New England Tree Fruit Growers Research 
Committee. We thank Jim Hardigg for allowing us to 
use his orchard for part of this work. 



vl^ *X* *X* *^ *X* 

0^ 0^ *Y* *X* *T* 



14 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



Two Odor Compounds Hold Promise 
for Increasing Trap Effectiveness for 
Plum Curculio 



Tracy Leskey, Max Prokopy, Anthea Yanopolous, Margaret Young, Brian Hogg, 

Fidelma Boyd, and Ronald Prokopy 

Department of Entomology, University of Massachusetts 

Larry Phelan 

Department of Entomology, Ohio State University 



There has been no trap developed for plum 
curculios (PCs) that successfully detects the beginning 
of PC activity in orchards each spring. Traps for other 
species of weevils such as the cotton boll weevil and 
the sugar cane weevil use a combination of attractive 
compounds present in host plant odors and weevil-pro- 
duced pheromones to increase trap effectiveness. PCs 
are attracted to odors produced by their host fruit over 
short distances as reported in the 1 996, 1 997, and 1 998 
Winter Issues of Fruit Notes. Under field conditions, 
PCs are attracted to host fruit odors at distances up to 
3 yards. Eller and Bartelt of Illinois found that male 
PCs produce an aggregation pheromone called 
grandisoic acid. Therefore, we decided to screen 18 
of the 19 compounds present in plum odor that were 
identified by Larry Phelan's lab at Ohio State Univer- 
sity in hopes of finding attractive compounds that could 
be used in combination with grandisoic acid to improve 
trap performance. Compounds were tested in the labo- 
ratory and in the field to identify those that were most 
attractive to PCs. 

Materials & Methods 

A profile of volatile compounds that comprises the 
odor of freshly picked plum fruit (2 weeks after bloom) 
was completed in the laboratory of Larry Phelan using 
a gas chromatograph and mass spectrometer. The 
compounds listed in Table 1 plus phenol were identified 
as comprising plum odor. All compounds were evalu- 
ated as potential attractants for PCs in laboratory and 
field experiments with the exception of phenol, which 



is highly toxic to mammals. Compounds were tested in 
the laboratory at three concentrations (1, 0.1, and 
0.01%) and in the field at two concentrations (5 and 
0.5%). 

PCs used in laboratory bioassays were collected 
from unsprayed wild plum and apple trees. For all labo- 
ratory tests, PCs were starved 24 hours prior to test- 
ing. Tests were conducted at the beginning of dark- 
ness. A 75 ul aliquot of the compound (the treatment) 
was pipetted onto a small cotton wick placed next to 
one of the two pipette tips that served as ports into a 
Petri dish test chamber. Either 75 ul of hexane or wa- 
ter (depending on the solubility of the compound) was 
used as a solvent control and was pipetted onto a sec- 
ond cotton square placed next to the other pipette port. 
Handling of PCs was kept to a minimum. A single PC 
was placed gently in the center of each Petri dish test 
chamber. Each time a specific compound was tested, 
12 PCs were tested singly in individual dishes and kept 
together on a tray. Dishes were then moved immedi- 
ately to the testing room. All bioassays lasted 2 hours, 
and all compounds were tested at least four times at 
each concentration ( 1 2 individual PC per tray x 4 trays 
= 48 individual PCs tested per compound and concen- 
tration). To measure the level of attraction to a par- 
ticular compound (the treatment), we used a Response 
Index (RI). The RI was calculated by subtracting the 
number of PCs responding to the control (C) from the 
number responding to the treatment (T), dividing this 
amount by the total number of PCs tested each time, 
and multiplying by one hundred. Thus RI = [(T - C) / 
12] x 100. The greater the RI value, the more attrac- 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



15 



Tabic I. Laboratory response indices (RIs) ol plum curculio ailulls lo individual odor compounds al three 
concentrations in solvent 



Compound 



1% 



0. 1 % 



0.01% 



Bcnzaldehyde 


-28 


-13 





Benzonitrile 


-29 


-10 


12 


Biphenyl 


-33 


-10 


-4 


Diphenyl methane 


-6 


-8 


19 


Ethyl acetate 


6 


-6 


13 


Ethyl butyrate 


15 


6 


8 


Ethyl isovalerate 


-4 


13* 


24* 


2-Hexenal 


-21 


-17 


-13 


2-Hexanol 


-4 


8 


8 


3-Hexanol 








-2 


2-Hexanone 


2 


10 





3-Hexanone 


17 


-10 


-10 


3-Hydroxy-2-butanone 


-17 


-6 


-17 


Isopropyl acetate 


-13 


-4 


4 


Limonene 


-7 


4 


18* 


Linalool 


-27 


-6 


13 


2-PentanoI 


-2 


13 





2-PropanoI 








-4 


* Significantly different from zero at odds of 19 to 1 . 



live was the stimulus. 

Ifi the field, green boll weevil traps were placed on 
the ground beneath the canopy of unsprayed apple trees 
approximately one yard from the trunk at each cardi- 
nal point. Compounds being tested were diluted in min- 
eral oil to a 5% concentration and applied to a 3-inch 
piece of cylindrical cotton wick that was wrapped in 
aluminum foil and attached by a wire to a boll weevil 
cone-shaped trap top. One end of the wrapped foil 
cylinder was clipped to permit dissemination of odor. 
For each tree, two traps were baited with an individual 
compound and placed at north and south positions, and 
two traps baited with mineral oil only (the control) were 
placed at east and west positions. After 48 hours, the 
number of PCs captured in each of the traps was 
counted, traps were baited with fresh wicks, and posi- 
tions of traps were rotated around the tree so that com- 
pound-baited traps were in east-west positions and 
control-baited traps were in north-south positions. This 
procedure was repeated 12 times. A .second experi- 



ment was conducted using only the most and least at- 
tractive compounds at two concentrations: 5 and 0.5%. 
In this experiment, procedures were nearly the same 
as in the first experiment except this procedure lasted 
only 24 rather than 48 hours, and was repeated only 10 
times. To measure the attractiveness of a particular 
compound, a Field Response Index was created by 
subtracting the number of PCs responding to the con- 
trol (C) from the number responding to the treatment 
(T), dividing by the total number of PCs captured in the 
treatment and control traps, and then multiplying by 100. 
Thus, RI = 1(T - C )/ (T + O] X 100. The greater the 
RI, the more attractive the compound. 

Results 

Laboratory Results. For compounds at 1 %, none 
of the RI values were significantly (Table I). AtO. I'^f, 
ethyl isovalerate jiiovided a positive and significant RI. 
Other compounds did not result in significant RIs at 



16 



Fruit Notes, Volume 6.^ (Number 3), Summer, 1998 



Tabic 2 I'lc'ld response indices (KIsj ol plum cuiciilio adulls lo (iilor cumpouruls :il conccnlralions ol 5 "/< . anil 
().5'/f in mineral oil. 



Compound 



Experiment 
(5%) 



Expcrimcnl 2 



5% 



0.5% 



Benzaldchyde 


13 


Benzonitriie 


33 


Biphenyl 


-27 


Diphenyl methane 





Ethyl acetate 


9 


Ethyl butyrate 


14 


Ethyl isovalerate 


71* 


2-Hexenal 


8 


2-Hexanol 


-13 


3-Hexanol 


-67 


2-Hexanone 


-18 


3-Hexanone 


-39 


3-Hydroxy-2-butanone 


26 


Isopropyl acetate 


-13 


Limonene 


38* 


Linalool 


10 


2-Pentanol 


-25 


2-Propanol 


-31 



80* 



25 



50 



20 



100* 



26 



Significantly different from zero at odds of 19 to 1. 



0.1%. At 0.01%, ethyl isovalerate and limonene re- 
sulted in positive and significant RIs, and all others re- 
sulted in nonsignficant RIs. 

Field Results. In the first field experiment, the 
only significant RIs were recorded for 5% solutions of 
ethyl isovalerate and limonene (Table 2). In a second 
set of experiments testing ethyl isovalerate and limonene 
(the most attractive compounds from the first field ex- 
periment) and 3-hexanol (the least attractive compound 
from the first field experiment), significant RIs were 
recorded for 5% solutions of ethyl isovalerate and li- 
monene, but not 3-hexanol at 5% or any of the three at 
0.5% (Table 2). 

Conclusions 

Data obtained from our laboratory and field ex- 



periments are in agreement. Two compounds, ethyl 
isovalerate and limonene, proved significantly attrac- 
tive to PCs under the test conditions described here. 
For the future, we plan lo test these two attractive com- 
pounds alone or in combination with male-produced 
pheromone as baits for the pyramid traps described in 
1997 and 1998 Winter Issues of Fruit Notes, and also 
for alternative trap designs including a circle trap and a 
twig-mimicking black cylinder trap to see if trap effi- 
cacy is increased, 

A ckn ow ledge m ents 

This work was supported by USDA Hatch funds 
and by the New England Tree Fruit Growers Research 
Committee. We thank Jim Hardigg for allowing us to 
use his orchard for part of this work. 



vt* vl> *!>* vl>* vT>* 
y^ *^ *^ #^ #^ 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



17 




Fruit Notes 



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Editors: Wesley R. Autio and William J. Bramlage 




iiMIW AC lAACC 

u i * I V . w r iv 1 /\ o ^ . 
Volume 63, Number 4 

FALL ISSUE, 1998 

Table of Contents 

Structural Refinement of Spheres 
for Controlling Apple Maggot 

Evaluation of Varying Doses of Different Toxicants for 
Use on Spheres to Control Apple Maggot Flies 

Fate of Apple Maggot Flies Alighting on Pesticide-treated 
Spheres in a Commercial Apple Orchard 

Evaluation of Scab on Fruit of New Apple Cultivars 

Testing Various Methods of Timing Summer Fungicides 

On-farm 1PM Education: Displays and Self-guided Tours 



Fruit Notes 



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Fruit Notes, Volume 63 (Number 4), Fall, 1998 



Structural Refinement of Spheres for 
Controlling Apple Maggot 

Starker Wright, Ronald Prokopy, and Xing Ping Hu 
Department of Entomology, University of Massachusetts 



Currently, there is no clear indication of the 
extent to which organophosphate insecticides will 
continue to be labeled for use in commercial apple 
production. If recent state and federal decision- 
making trends can be used as a guide for future 
action, then we should prepare ourselves for the 
possibility that the pre-harvest interval for orga- 
nophosphate insecticides (particularly 
azinphosmethyl) may be lengthened considerably, 
possibly to 60 days or more. The purpose for do- 
ing this would be to eliminate all detectable resi- 
due on fruit at harvest, a principal aim of the Food 
Quality Protection Act (FQPA). This same sce- 
nario could well apply to permissible use patterns 
of carbamate insecticides, the only other class of 
labeled materials known to be at least moderately 
effective against apple maggot. 

For many years (as reported in Fruit Notes), 
we have conducted studies aimed at development 
of behavioral control of apple maggot using traps 
as a substitute for insecticide applications. These 
studies have led to the development of pesticide- 
treated spheres as a potential alternative in com- 
mercial apple production. Such spheres are in- 
tended to be inexpensive, easy to use, safe to handle, 
and to offer reliable control of apple maggot. 

In 1997, we began an extensive comparison of 
odor-baited sticky coated spheres, pesticide-treated 
wooden spheres, and biodegradable pesticide- 
treated spheres for direct control of apple maggot 
flies (AMF) in commercial orchards. This study 
was conducted in eight commercial apple orchards, 
each containing four blocks of 49 trees each. In 
each orchard, one block received three insecticide 
sprays for AMF control, one block was surrounded 
by sticky-coated wooden spheres, one block was 
surrounded by pesticide-treated wooden spheres, 
and one block was surrounded by biodegradable 
pesticide-treated spheres. The results [Fruit Notes 



62(4)] showed that pesticide-treated biodegradable 
spheres performed as well as sticky spheres and 
considerably better than pesticide-treated wooden 
spheres on which we were unable to preserve an 
effective level of feeding stimulant. None of the 
three trap types provided quite the level of AMF 
control as 3 insecticide sprays did. In the case of 
biodegradable pesticide-treated spheres, compro- 
mising factors were that some spheres cracked pre- 
maturely, some were eaten by birds and/or rodents, 
and some were overgrown by fungi, reducing the 
number of effective spheres comprising the barrier 
to fly immigration into some blocks. Despite short- 
comings, our 1997 findings were encouraging, as 
all sphere types performed well under high pest 
pressure in commercial orchards. 

Our goal for 1998 was to conduct experiments 
leading to improved versions of pesticide-treated 
spheres and to evaluate these for direct control of 
AMF. Here we report on structural refinements of 
both pesticide-treated biodegradable spheres and 
pesticide-treated wooden spheres. 

Materials & Methods 

To maximize effectiveness and durability of bio- 
degradable spheres, we addressed each of the short- 
comings of such spheres experienced in 1997: 

1 ) To combat premature breakdown of biodegrad- 
able sphere bodies, we evaluated seven differ- 
ent structural compositions. We assessed each 
body type for drying ti-ne, hardness, and resis- 
tance to humidity. 

2) To ease deployment, we replaced the trouble- 
some string hangers with wire hooks, and used 
a metal disc beneath each sphere to support 
the weight of the sphere body. 

3) To prevent consumption of spheres by rodents, 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



we evaluated five different fornuilations of hot 
pepper additive, whose active ingredient (cap- 
saicin) is known to deter rodent feeding. 

4) To reduce damage caused by birds, we evalu- 
ated black spheres versus red spheres. 

5) To inhibit growth of fungi on the surface and 
in the body of the spheres, we incorporated 
1.0% sorbic acid mto the ingredients of each 
sphere body as a preservative. 

In an attempt to extend the residual activity of 
sucrose as the necessary feeding stimulant on pes- 
ticide-treated wooden spheres, each sphere was fit- 
ted with a 1.25-inch plastic dish containing 15 
grams of molten sucrose, which cooled and hard- 
ened after pouring. In concept, as these spheres 
are exposed to rainfall, the sphere surface is re- 
treated with a dilute sucrose solution from the res- 
ervoir atop the sphere. If there was a constant 
release of sugar to the sphere surface under condi- 
tions of rainfall, then ideally each sphere would 
have enough sucrose to replenish the active supply 
through several inches of rainfall. 

In addition to structural modifications of pes- 
ticide-treated spheres, we increased the level of 
imidacloprid (Merit formulation, 75 WP) from 
1.5% to 2.0% active ingredient to extend late-sea- 
son effectiveness of the spheres (see following ar- 



ticle), l-'or all pesticidc-treated spheres, the toxi- 
cant (iniKiacloprid) was applied to the spheres at 
2.0% a.i. in Glidden Latex Gloss Enamel paint. 
In 1998, we evaluated odor-baited sticky spheres, 
modified wooden pesticide-treated spheres, and im- 
proved biodegradable pesticide-treated spheres in 
32 commercial orchard blocks. Blocks used in 1998 
were the same blocks used in 1997; spheres were 
emplaced in eight commercial orchards, each con- 
taining four blocks of 49 trees. Each block receiv- 
ing spheres was surrounded by 26 spheres of the 
same type at a 5-meter interval, and each sphere 
was baited with a vial of butyl hexanoate. 

Results 

In laboratory tests under conditions of artifi- 
cial rainfall, the following body composition 
proved the most durable for biodegradable spheres: 
16% wheat flour, 16% pre-gelatinized corn flour, 
5% corn starch, 20% powdered sugar, 13% granu- 
lated sugar, 7% corn syrup, 8% glycerol, and 9% 
water. Spheres of this composition were found to 
harden very quickly and were much more resis- 
tant to premature breakdown than the body style 
used in 1997. 

Of materials tested to deter rodent feeding, the 
best product was African cayenne pepper powder, 



Table 1. Control of apple maggot flies by odor-baited sticky-coated wooden spheres, wooden 
pesticide-treated spheres (PTS), biodegradable pesticide-treated spheres, or three applications 
of azinphosmethyl in 32 blocks of medium-size apple trees in eight commercial orchards in 
1998. 





Mean no 


flies captured per block 


Mean 


0/ 

/o 




Treatment 


Perimeter tra 


ps 


Interior monitoring 
traps 


injured fruit per 
block* 


Sticky spheres 
Wooden PTS 
Biodegradable PTS 
Insecticide sprays (3) 


1702.5 






137.3 
210.8 
272.4 
123.6 






0.70 
2.93 
0.77 
0.59 



* Values here represent injury during five sampling periods (every 2 weeks from mid-July 
tiirough harvest), during which 100 fruit per block were sampled on each sampling date. 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



mixed at 5% with sphere body ingredients. Sub- 
sequent lab and field tests indicated that AMF were 
completely unaffected by the pepper additive, 
whereas damage to spheres by rodents was greatly 
reduced or eliminated. Field assays revealed that 
bird damage to biodegradable spheres was substan- 
tially reduced by painting spheres black, thus mak- 
ing them less visually attractive to foraging birds. 
Fortunately, AMF are equally attracted to black 
and red spheres. Given this early-season progress, 
we were confident in the potential of biodegrad- 
able pesticide-treated spheres to offer AMF con- 
trol comparable to sticky-coated wooden spheres. 
Data trends established in the 1997 comparison of 
sphere types held true in 1998. Results for 1998 
(Table 1) showed that biodegradable pesticide- 
treated spheres performed about as well as sticky 
spheres (0.77% and 0.70% injured fruit, respec- 
tively) and nearly as well as three insecticide appli- 
cations (0.59% injured fruit). As in 1997, wooden 
pesticide-treated spheres released the entire sucrose 
supply too quickly, and did not perform as well 
(2.93% injured fruit). Unfortunately, many bio- 
degradable spheres required replacement after 
about a month of field exposure due to softening 
and bursting of the sphere bodies. 

Conclusions 

Pest pressure in commercial orchards in 1998 
was even higher than in 1997 (an average of 1702 
AMF per block captured by the 26 sticky spheres 
per block). Despite shortcomings of biodegrad- 
able and wooden pesticide-treated spheres, we are 
nonetheless encouraged by the 1998 results, par- 



ticularly by the performance of biodegradable 
spheres under very high pest pressure. With fur- 
ther structural modifications and pending commer- 
cial production of biodegradable sphere bodies, we 
are becoming increasingly confident in recommend- 
ing use of sphere traps in place of insecticide sprays 
for control of AMF in commercial orchards. As 
discussed m the Introduction, development of al- 
ternatives for control of AMF is gaining emphasis 
given the implications of FQPA implementation. 

For the 1999 field season, we will again com- 
pare the efficacy of sticky-coated wooden spheres, 
pesticide-treated wooden spheres, and pesticide- 
treated biodegradable spheres for direct control of 
AMF. In 1999 field trials, pesticide-treated wooden 
spheres will be augmented with a new sucrose-re- 
lease mechanism, and biodegradable spheres used 
in 1999 will be commercially-made prototypes, 
produced by a private corporation under USDA 
supervision. 



Acknowledgments 

This work was supported by state/federal IPM 
funds, a grant from the Washington Tree Fruit Re- 
search Commission, a USDA SEA CSREES grant 
(# 97-34365-5043), and a SARE grant (USDA 96- 
COOP-1-2700). As always, we are grateful to the 
seven growers who participated in this study: Bill 
Broderick, Dana Clark, Dave Chandler, Tony Lin- 
coln, Wayne Rice, Dave Shearer, and Tim Smith; 
and to our field technicians: Jon Black, Joel Benton, 
Anthony Minalga, Stephen Lavallee, Eric 
Gemborys, and Max Prokopy. 



\f^ Kf^ Kf^ \r %f 
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Fruit Notes, Volume 63 (Number 4). Fall. 1998 



Evaluation of Varying Doses of Different 
Toxicants for Use on Spheres to Control 
Apple Maggot Flies 

Ronald Prokopy, Starker Wright, Brad Chandler and Xingping Hu 
Department of Entomology, University of Massachusetts 



In the 1997 Fall issue of Fruit Notes, we re- 
ported that imidacloprid was a promising alterna- 
tive to dimethoate as a toxicant for application to 
pesticide-treated spheres for controlling apple mag- 
got flies (AMF). We also reported that imidacloprid 
at 1.5% active ingredient (a.i.) in paint afforded 
longer residual activity than imidacloprid at 0.5% 
a.i. in paint, and that a Merit 75 WP formulation 
of imidacloprid in paint was more effective than a 
Provado 1.6 F formulation in paint at 0.5% a.i., 
though not at 1.5% a.i. 

The unusually large numbers of AMF in some 
Massachusetts commercial apple orchards in 1998 
allowed early-season direct observations of the 
behavior of AMF after alighting on imidacloprid- 
treated spheres. These observations suggested to 
us that by increasing the dose of imidacloprid on 
spheres beyond the 1.5% active ingredient used 
heretofore, we might be able to capitalize on con- 
tact-type toxicity of imidacloprid, thus diminish- 
ing the need to maintain feeding stimulant (sucrose) 
on the sphere surface. Such a high-dose approach 
was thought previously to be impractical, owing 
to the handling risk associated with higher doses 
of our originally-adopted toxicant, dimethoate. 

Here, we report on 1998 studies of AMF re- 
sponses to four different doses of imdacloprid in 
latex paint, with and without the addition of su- 
crose as feeding stimulant. We also report on AMF 
responses to three new candidate toxicants: 
spinosad, sugar ester, and fipronil. All three, like 
imidacloprid, are considered to be comparatively 
safe for handling by humans. 

Materials & Methods 

In our first test, we painted the inside surface 
of small plastic cups with a mixture of Glidden 



Red Latex Gloss Enamel paint and either 0.1, 0.5, 
1.0, or 5.0% a.i. of one of the following potential 
toxicants: imidacloprid (Merit 75 WP), spinosad 
(SpinTor 22.8 F), sugar ester (SCO 3483, 100%), 
or fipronil (Regent 80 WG). No sugar was added 
to any mixture. After the mixture dried, 10 AMF 
were confined in each of two cups of the same treat- 
ment type for 10 minutes, following which AMF 
were transferred to clean cups supplied with food 
and water. Mortality was assessed after 72 hours. 

For our second test, we focused on the two 
toxicants that showed the most promise in the first 
test: imidacloprid and fipronil. Each of these toxi- 
cants was evaluated at 2, 4, 8, and 16% a.i. in 
Glidden Red Latex Gloss Enamel paint (no sugar 
added) applied to wooden spheres. After drying, 
spheres were hung in orchard trees and returned 
to the laboratory after 3, 6, 9, or 12 weeks for 
evaluation of toxicity to AMF. For evaluation, 30 
AMF were placed individually on a sphere of each 
treatment type and allowed to remain 10 minutes, 
following which AMF were transferred to small, 
clean cups supplied with food and water. Mortal- 
ity was assessed after 24 hours. Half of the spheres 
of each treatment type received a 20% sucrose so- 
lution just prior to testing. The other half received 
no sucrose. 

For our third test, we again focused on 
imidacloprid and fipronil, but in this experiment, 
we evaluated the behavior of sphere-exposed AMF 
shortly after removal from spheres. Spheres were 
treated with 2.0% a.i. imidacloprid or fipronil in 
Glidden Red Latex Gloss Enamel paint and exposed 
for 3 weeks in orchard trees. Just before testing, 
all spheres received a 20% sucrose solution. For 
each treatment, 32 AMF were placed individually 
on a sphere and allowed to feed for up to 10 min- 
utes. One hour after feeding, each fly was trans- 



Fruit Notes, Volume 63 (Number 4), Fail, 1998 



fcrred to a leaf nc.ir the center of the canopy of a 
small non-frinting fig tree and allowed to forage 
freely for 15 muiutes. The niinibcr of leaves vis- 
ited was recorded. Immediately thereafter, each 
fly was placed on a ripe hawthorn fruit, and pro- 
pensity to lay an egg was observed. 

Results 

In our first test, conducted with no sugar added, 
20, 80, and 100% of AMF died by contact toxic- 
ity alone when confined in plastic cups treated with 
0.5, 1.0, and 5.0% a.i., respectively, of imidacloprid 
in paint (Table 1). None died at 0.1% a.i. of 
imidacloprid. The only other toxicant causing 
AMF mortality was fipronil, where 107o of AMF 
died by contact toxicity alone after exposure to 
5.0% a.i. of this material. Even though both 
spinosad and sugar ester conceivably might be 
somewhat toxic to AMF if ingested together with 
sugar or when applied alone to foliage, neither 
material caused any toxicity by contact alone when 
mixed in latex paint. 

In our second test, results showed that in the 
presence of sucrose, mortality of AMF was consis- 
tently high (70% or more) on spheres treated with 
imidacloprid, even after 12 weeks of sphere expo- 
sure to outdoor weather in orchard trees (Figure 
1). Provided that sugar was present, the dose of 



imidacloprid had little effect on AMF toxicity, with 
2% a.i. being about as toxic as 16% a.i. at all evalu- 
ation periods (3, 6, 9, and 12 weeks). In contrast, 
in the absence of sucrose, toxicity of imidaclcjprid- 
treated spheres to AMF did not exceed 15% at 12 
weeks of orchard exposure, even at the highest dose 
tested (16% a.i.). Results for fipronil roughly par- 
alleled those for imidacloprid at 3, 6, and 9 weeks 
of orchard exposure. However, at 12 weeks, even 
in the presence of sucrose, lower doses of fipronil 
(2 and 4% a.i.) yielded no more than 40% mortal- 
ity of AMF. A dose of 8% fipronil was required 
before toxicity approached that of 2% imidacloprid 
at 12 weeks. In the absence of sucrose, toxicity 
from contact with fipronil, as with imidacloprid, 
was virtually nil at 12 weeks, irrespective of dose. 
In our third test, results showed that only a 
minority of AMF exposed to spheres treated with 
2% a.i. imidacloprid and sucrose were capable of 
foraging within a plant canopy after exposure, and 
of those that could forage, an average of only one 
leaf was visited for every three flies tested (Table 
2). Moreover, only 6% of assayed AMF attempted 
to oviposit in a hawthorn fruit. In contrast, al- 
most all AMF exposed to spheres treated with 2% 
a.i. fipronil were capable of foraging within a plant 
canopy, with the average number of leaves visited 
nearly equaling the number visited by AMF that 
were exposed to spheres lacking pesticide. Also, 



Table 1. Fate after 72 hours of apple maggot flies confined for 10 minutes in plastic cv 
with insecticide in latex paint (no sugar added). 


ps coated 


Insecticide 




Active 


ingredient (a.i.) concentration 


(%)* 




0.1% a.i 


0.5% a.i. 1.0% a.i. 


5.0% a.i. 


Imidacloprid (Merit 75 WP) 
Fipronil (Regent 80 WG) 
Spinosad (Spintor 22.8 F) 
Sugar Ester (SC03483 100% a.i.) 










Mortality (%) 

20 80 





100 
10 






For each dose of each insecticide, ten 


flies 


were confine 


d in each ot two cups for 10 minutes. 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



I'lguic I rerCL'Ml iiiDilalilv nl .ipplc in.iggol llics cxpuscil Id wooiicn pcsliculc-lrcalcd spheres siili|ccle(l lo ^, (). 
') or 12 weeks dI liekl exposure aller UealnienI w rlli varying conceiilralrons ol insectieide. I'Ires were lesled on 
spheres with and without suizar added lo llic surface prror lo lestinc. 



100 



c 60 
o 

E 

>- 40 



20 



3 weeks exposure 




% active ingredient 



16 



100 ' 

^ 80- 

? 60 
o 

E 

>■ 40 

^ 20 






6 weeks exposure 




H 


4- 




1 ' ' ' 1 


-"■'•■*■ 


+ 






" +' 






=^^ 


, - - ' ^^^^ 


-^--rrrrr 


_.. 




2 


4 8 
% active Ingredient 


16 



100 - 
>- 80- 

1 60 

E 

>. 40 ■ 

^ 20- 

- 




9 weeks exposure 








_.--*' 




4- 


- + 






t I - ■ ' 


. " 




■\ '■ ■ ■ 


1 


— h 




77^ ^-^^^ -^^jj 




- - ^^ 


-— — 




2 


4 

% active ingredient 


8 


16 



100 
>- 80 

? 60 

E 

^ 40 

°- 20 





12 weeks exposure 





. 


.... _ . ■ ■! 




^ — ■ — ' 


1-^ ^ , - - ■ 


+--■'"■ 


-..----'--+'' 


__...+-■" \r 





.-■■' 













1 


— \ 







4 8 

% actrve rngredlent 



16 



Imidacloprid Fipronil 

+ + + + in line indiealcs that spheres were treated with 20% sucrose solution prior to testing. 



Fruit Notes, Volume 6.3 (Number 4), Fall, 1998 



Tnble 2. f-'ornging behavior of .ipplc maggot fly females, subsequent egglaying propensity and 
percent mortality following feeding on untreated, fipronil-treated or nnidacloprid-treated red 
wooden spheres. Foraging and cgglaynig behaviors were evaluated I hour after exposure to spheres. 





Females tested 


Sphere treatment 
















per 


treatement 












Parameter measured 




(no.) 


Untreated 


F 


ipronil 


Im 


dacloprid 


Mean feedmg time on spheres (sec.) 




32 


596 




579 




363 


Flies capable of foraging on tree (%) 




32 


100 




91 




44 


Mean foraging tune (sec.) 




-- 


844 




760 




585 


Mean number of leaves visited 




32 


2.3 




1.6 




0.3 


Flies laymg an egg (%) 




32 


61 




16 




6 


Mortality: 24 hours (%) 




32 


3 




28 




71 


72 hours (%) 




32 


10 




82 




83 



Treated spheres contained 2% active ingredient of insecticide in latex paint. All spheres were 

subjected to 3 weeks field exposure and then were re-treated with 20% sucrose solution just 

prior to testing. 

Maximum permited feeding time = 600 seconds. 

Flies were placed individually on a small, caged tree. Numbers represent mean foraging time of 

flies capable of foraging. Maximum permitted canopy foragmg time = 900 seconds. 

Immediately after foraging, each fly was exposed to a hawthorn fruit. Maximum permitted time 

on fruit = 600 seconds. 



16% of AMP that were exposed to fipronil-treated 
spheres attempted to lay an egg. Together, the re- 
sults of the behavior tests reflect the fact that 
fipronil is a much slower-acting compound than 
imidacloprid. AMF mortality following ingestion 
of fipronil was only about a third the amount at 
24 hours after exposure as at 72 hours afterward, 
whereas with imidacloprid, mortality at 24 hours 
was nearly equal to that at 72 hours (Table 2). 

Conclusions 

Our combined findings show that imidacloprid 
performed better as an AMF toxicant on pesticide- 
treated spheres than did any of three other candi- 
date toxicants tested here: fipronil, spinosad and 
sugar ester. Imidacloprid at 2% a.i. in Glidden 



Red Latex Gloss Enamel paint gave excellent sea- 
son-long ( 1 2 weeks) AMF control provided that it 
was ingested with a feeding stimulant (sucrose). It 
gave very poor control, as did fipronil, in the ab- 
sence of sucrose, irrespective of dose used (16% 
a.i. was the highest dose tested). A low dose of 
imidacloprid, such as 2% a.i., not only is less ex- 
pensive than a higher dose but is safer for those 
handling pesticide-treated spheres. Imidacloprid 
rapidly immobilized AMF that ingested it, result- 
ing in very little or no subsequent foraging and 
egglaying activity of exposed AMF. Because 
imidacloprid seems to be an ideal toxicant for use 
in conjunction with sucrose on pesticide-treated 
spheres for controlling AMF, we are hopeful that 
the registrant (Bayer Corporation) will see fit to 
officially register its use for this purpose. 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



Acknowledgments 

This work was supported by a grant from the 
Washington Tree Fruit Research Commission and 



USDA SEA CSREES grant # 97-34365-5043. We 
thank Gary Puterka of the USDA Regional Fruit 
lab in Kearneysville, WV for providing the sugar 
ester. 



^C •'k *C *C *C 



Fate of Apple Maggot Flies Alighting on 
Pesticide-treated Spheres in a Commercial 
Apple Orchard 

Xingping Hu, Eric Gemborys, Max Prokopy, and Ronald Prokopy 
Department of Entomology, University of Massachusetts 



As mentioned in the preceding article, unusu- 
ally large numbers of apple maggot flies (AMF) 
invaded certain commercial apple orchards in 
Massachusetts in 1998. In most cases, invasion 
was attributable to a combination of large num- 
bers of AMF emerging from overwintered pupae 
beneath unmanaged apple trees nearby commer- 
cial orchards and to near or total absence of any 
fruit on such unmanaged trees, leading to AMF 
abandonment of unmanaged trees and movement 
to fruiting trees in commercial orchards. We took 
advantage of this situation in a cooperating orchard 
and studied the fate of AMF that were observed to 
alight on pesticide-treated red spheres. 

Methods & Materials 

Eight wooden spheres, 3 inches in diameter, 
were coated with a mixture containing 2% active 
ingredient of imidacloprid (Merit 75 WP), 20% 
sucrose, and 78% Glidden Red Latex Gloss Enamel 
paint. Four similar spheres, serving as non-toxi- 



cant checks, received only the sucrose and paint. 
All of the spheres were exposed outdoors for 3 
weeks before testing (but no rain fell during this 
period). On three sunny days (July 21, 27, and 
29), each of three observers hung two pesticide- 
treated and one check sphere about 2 feet apart in 
an apple tree and watched each sphere continu- 
ously for alighting AMF for a period of about 6 
hours per day. An attempt was made to capture 
each AMF after it departed or fell from a sphere. 
Captured AMF were placed singly in small clean 
cups, supplied with food and water, and observed 
1, 24, and 72 hours later for mortality. 

Results 

In all, 36 AMF were observed alighting on pes- 
ticide-treated spheres and 19 AMF on untreated 
check spheres. Of the 36 alighting on pesticide- 
treated spheres, the median duration of stay was 
about 3 minutes and 25 died while still on a sphere 
or within 1 hour after having fallen from a sphere. 



10 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



All remaining 1 1 AMF flew from a pesticide-treated 
sphere to nearby foliage. Of these, six were cap- 
tured. All six died within 24 hours. The other five 
AMF evaded capture. Of the 19 AMF alighting 
on untreated check spheres, the median duration 
of stay was about 4 minutes and none died while 
on a sphere. Unfortunately, none could be cap- 
tured after departing an untreated sphere, as flight 
was too fast and far to permit capture. 

Conclusions 



Results of this study of responses of wild-popu- 
lation AMF in a commercial orchard to wooden 
spheres treated with imidacloprid, sucrose and la- 
tex paint confirm results of a study reported in the 

preceding article conducted using laboratory-main- Acknowledgments 
tained AMF. Among all wild-population AMF 
observed here to alight on pesticide-treated spheres, 
86% (31 of 36) died within 24 hours and most 
died within 1 hour. The fate of the 14% that were 



not captured after alighting is unknown. Some of 
these also may have died. In the preceding article, 
data showed that pesticide-treated spheres com- 
parable both in type (2% a.i. imidacloprid) and 
field-exposure before testing (3 weeks) to those 
used here yielded 75% mortality of tested AMF. It 
is thus reassuring to know from this study of wild- 
population AMF that we can use response patterns 
of laboratory-maintained AMF placed directly on 
pesticide-treated spheres as an accurate guide to 
the performance of pesticide-treated spheres in 
commercial orchards. It is also reassuring to know 
that pesticide-treated spheres treated with 2% a.i. 
imidacloprid and sucrose are highly effective 
against AMF. 



This work was supported by a grant from the 
Washington Tree Fruit Research Commission and 
a USDA SEA CSRESS grant (#97-34365-5043). 



^C *C ^C ^C *C 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



11 



Evaluation of Scab on Fruit of New 
Apple Cultivars 

Daniel R, Cooley, Arthur Tuttle, James Hall 

Department of Microbiology, University of Massachusetts 

Duane Greene 

Department of Plant and Soil Sciences 



While scab resistance has not proven to be the 
most important characteristic of new apple culti- 
vars, it is still useful to know how susceptible new 
cultivars are to scab. A grower is probably wisest 
to choose a new cultivar based on marketability 
and production, but then treat it for scab ac- 
cording to susceptibility to the disease. 

It was difficult to control scab in 1998, and 
a test block of new cultivars at the Horticul- 
tural Research Center in Belchertown, MA 
developed significant foliar and fruit scab over 
the growing season even though fungicides 
were applied. These cultivars were planted in 
five replicated blocks, and we decided to evalu- 
ate scab incidence to determine if there were 
differences. All the trees were on M.9 root- 
stock, except two that also were on Mark 
(Golden Delicious and Yataka). On Septem- 
ber 3, 1998, scab on the fruit was evaluated, 
and incidence was calculated as a percent of 
total fruit per tree. 

The only cultivar in the planting that is al- 
ready widely planted commercially in Massa- 
chusetts is Golden Delicious. Golden Delicious 
is generally reported as not very susceptible to 
scab, and this evaluation supported that as- 
sumption. While Golden Delicious had about 
10% scab incidence, scab incidence over the 
whole planting ranged from to 49%. Gala 
Supreme was quite resistant to scab, with 0% 
incidence. Similarly, Sansa, a Gala x Akane 
cross, also had 0% scab. As might be expected, 
two scab-resistant cultivars from the Purdue/ 
Rutgers/Illinois program, Enterprise and 
Goldrush, and one from the New York pro- 
gram, NY-75414-1, also did not show any 



scab. Suncrisp, progeny of a Golden Delicious 
cross, had very little scab (6%). 

Unfortunately, two cultivars that would have 
been very interesting to evaluate, Honeycrisp and 
Ginger Gold, did not produce fruit in 1998. 



Table 1. Evaluation of fruit scab in a variety 
block (NE 183) at the Horticulture Research 
Center, Belchertown, MA, September 3, 1998. 



Cultivar/Rootstock 


Apples wi 


thscab(%) 


Enterprise 





c 


Gala Supreme 





c 


Sansa 





c 


NY 75414-1 





c 


Goldrush 





c 


BC8M 15-10 


4 


c 


Suncrisp 


6 


c 


Golden Delicious 


10 


c 


Golden Delicious/Mark 


11 


c 


Shizuka 


20 


be 


Cameo 


28 


abc 


Fuji 


32 


a be 


Orin 


33 


abc 


Braeburn 


39 


ab 


Golden Supreme 


42 


ab 


Yataka 


44 


ab 


Arlet 


45 


ab 


Yataka/Mark 


49 


a 


NY 429 


49 


a 



Means followed by the same letter are not 
significantly different at odds of 19:1. 



12 



Fruit Notes. Volume 63 (Number 4), Fall, 1998 



Braeburn and Fuji were both quite susceptible to 
apple scab. 

Results of this test were similar to those in for- 
mal disease analyses done in Connecticut, Michi- 
gan, New York, Virginia, and West Virginia 



All apple cultivars do not get scab to the same 
degree. The key question, for which we do not yet 
have an answer, is how much less can we spray the 
less susceptible cultivars? That will have to be re- 
searched. 



%r ^r \r ^r ^r 
*^i ^C •'k •'k •'k 



Testing Various Methods of Timing 
Summer Fungicides 

Kathleen Leahy 

Polaris Orchard Management, Colrain, Massachusetts 

Thomas Clark 

Clarkdale Fruit Farm, Deerfield, Massachusetts 

Ezekiel Goodband 

Alyson's Apple Orchard, Walpole, New Hampshire 



The summer diseases, sooty blotch and flyspeck 
are the cause of most of the fungicide use after 
June in New England orchards. Using an improved 
understanding of the biology of these diseases, and 
specifically the wetness-hour model developed by 
Turner Sutton and his colleagues , has allowed 
growers to reduce fungicide usage in North Caro- 
lina and other mid-Atlantic states. We wanted to 
test this model to see whether it is viable in New 
England conditions. 

In a nutshell, the method developed by Brown 
and Sutton in North Carolina is based on the biol- 
ogy of the sooty blotch and flyspeck fungi. It al- 
lows the first summer fungicide to be delayed until 
200-250 hours of wetness (counting only wetting 
periods of 4 hours or more) after the last scab fun- 
gicide. With our relatively dry summers, we gen- 
erally reach this threshold in early to mid-August. 
Thus, using this method, we could, in most years, 
save a couple of fungicide applications and have 



greater flexibility in timing summer fungicides with 
respect to insecticides and miticides/summer oils. 
We also decided to try a somewhat less radical 
method, based on work by David Rosenberger in 
New York, showing that fungicide retention dur- 
ing the summer is such that fungicides need not be 
re-applied until 150 hours of wetness (no mini- 
mum threshold) having occurred since the previ- 
ous fungicide. This would still provide a measure 
of flexibility in summer fungicide use. 

Materials & Methods 

The two cooperating orchards were located in 
the Connecticut Valley, one in Walpole, NH and 
the other in Deerfield, MA. In these orchards, the 
test blocks were divided into three Vi acre plots, 
and each plot was treated according to one of three 
summer fungicide programs: 1) the 'standard' pro- 
gram of a fungicide application every three weeks 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



13 



Table 1. 


The percent of fruit wi 


th flyspeck in a 50-fruit sample from each 


tree 


evaluated 


weekly from 


mid July 


and at harvest in 


1998. 










Clarkdale 








Alyson's 






Standard 


NY 


NC 


Standard 




NY 




NC 


Check 



















































































4 












2 


2 


2 





8 












2 


18 


6 


6 


14 


2 




2 




8 


20 


10 





14 


10 




2 




8 


22 


1 00- fruit sample taken 


at Mcintosh harvest, 9/11/98 










15 


10 


13 


43 




- 




~ 


- 


1 



through June, July, and August; 2) the 'New York' 
program of waiting until 150 hours of wetness had 
accumulated since the most recent fungicide appli- 
cation; and 3) the 'North Carolina' model of wait- 
ing until 200-250 hours of wetness had accumu- 
lated after the primary infection period for these 
diseases. 

A modified hygrothermograph unit was used 
to measure the wetting periods in both orchards. 
The weather units were set out prior to blossom. 
The time of petal fall was noted (May 10 at 
Clarkdale Orchards; May 1 1 at Alyson's Apple 
Orchard) and wetness-hours were accumulated 
beginning 10 days after petal fall (May 20 and May 
21, respectively). Trees in both blocks are on M.7 
rootstock. The Clarkdale block consisted of 
Golden Delicious and Mcintosh, about 15 years 
old, with rows running east-west, and the Alyson's 
block was Mcintosh and Empire, about 12 years 
old, with rows running north-south. 

This was an unusually wet year in the North- 
east. In a more typical year we would not reach 
the 'North Carolina' threshold until early August, 
but in 1998, we reached this threshold by early 
July. Over 100 hours of wetness occurred during 



a single week in June. The specific threshold dates 
were: at Clarkdale Orchards, the New York thresh- 
old of 150 hours from the last apple scab fungi- 
cide was reached on June 22, and the North Caro- 
lina threshold of 200 hours was reached on July 3. 
At Alyson's Apple Orchard, the New York thresh- 
old was reached on June 24, and the North Caro- 
lina threshold on July 2. Because the New York 
threshold at Clark's was reached at the same time 
that he was planning a 'standard' spray, both the 
'standard' and 'New York' plots were treated on 
the same date. 

The first summer fungicide applications were 
made on June 22, June 22, and July 9 at Clarkdale 
for the standard program, NY program, and NC 
program, respectively. The first summer fungicide 
applications were made on June 24, July 2, and 
July 16 at Alyson's for the standard program, NY 
program, and NC program, respectively. 

At Alyson's, Mr. Goodband decided to test a 
yet more radical approach than what we had origi- 
nally proposed. The fungicide application on June 
24 actually coincided with the NY threshold, and 
the July 2 date was when the 200-hour NC thresh- 
old was reached. The application on July 16 was 



14 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



Table 2. 


The 


percent of Mcintosh 


fr 


Lilt With fivs 


pec 


k m a 


50-fruit 


sample 


from each 


tree eval 


lated 


weekly 


from mid Se 


ptember throL 


gh 


early 


October 


in 1998 






Clarkdale 














Alyson's 






Standard 




NY 


NC 






Standard 




NY 




NC 


Check 


10 




6 


28 






6 




6 




10 


34 


56 




46 


52 






4 




6 




10 


26 


58 




62 


62 






10 




18 




10 


30 


68 




72 


72 






— 




— 




- 


— 


1 



at 336 wetness-hours from 10 days after petal fall, 
and 262 wetness-hours from the previous fungi- 
cide. Once the first summer fungicide was applied 
in each section, that section thereafter continued 
to receive a regular fungicide program. 

Results 

Because of the early accumulation of the thresh- 
old level of leaf wetness hours, sampling (50 fruit 
per section per week) began in mid-July instead of 
early August as planned, but no symptoms were 
seen even in check trees until mid-August. When 
flyspeck symptoms began to appear (virtually all 
the summer disease seen this year was flyspeck), 
they appeared first in the most lightly-sprayed plots. 
Despite the early wetness, there was not a signifi- 
cant level of flyspeck except in the check trees un- 
til mid-September. 

As can be seen from Table 1, there were few 
significant differences in summer disease occurrence 
except between the treated and check trees, but 
there was a trend toward somewhat higher disease 
in the 'radical' plot at Alyson's. When Mcintosh 
fruit were harvested in this plot, a random survey 
of fruit showed over 40% with flyspeck, which is 
not commercially acceptable. It was clear that this 
'radical' option did not provide acceptable control 
of flyspeck. Because of the advanced season and 
the dry conditions in August, the fruit in the other 
two plots were harvested before a proper survey 



could be done, but it was evident that control was 
satisfactory in these two plots. 

At Clarkdale, there was very little difference 
between treated plots (the intended check trees were 
sprayed so the data were not included), and a har- 
vest survey of 100 Mcintosh per plot showed no 
significant difference nor any trend between treat- 
ments. 

Once the Mcintosh had been harvested, it be- 
came evident that there were differences in flyspeck 
occurrence between varieties in both orchards. This 
effect had been masked by the random zigzag pat- 
tern through the plot adopted when sampling fruit 
in the regular weekly sessions. At Alyson's, the 
Empires had much less flyspeck than the Mcin- 
tosh, whereas at Clarkdale, the Golden Delicious 
had much more flyspeck than the Mcintosh. These 
differences were presumably not owing to varietal 
susceptibility, since the literature indicates that 
apple varieties are essentially identical in their sus- 
ceptibility to flyspeck. We believe that the differ- 
ences were owing to the more open growth habit 
of Empires vs. Mcintosh at Alyson's, generating a 
less favorable (lower humidity) environment for 
the organism, whereas at Clarkdale the strikingly 
high level of flyspeck throughout all three treat- 
ments indicates that this entire row did not receive 
a summer fungicide application - perhaps the last 
scab fungicide on June 9. 

Mite sampling in the test plots did not show 
any difference in either pest or predator mite num- 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



15 



bers. This was as we expected, since the first year 
of reducing fungicide is unhkely to produce a dra- 
matic effect on the mite population. 



Discussion 

In general both the New York and North Caro- 
lina methods of timing fungicide applications 
seemed to work very well, under unusually chal- 
lenging conditions for this region. It is clear, 
though, that extending the number of wetness- 
hours beyond the 250 recommended by the North 



Carolina model poses an unacceptable risk to the 
crop. The economic savings from reduced sprays 
overall were less than $10 per acre, but even this 
amount could be significant, given the slim profit 
margins in apple-growing at this time. The major 
benefit of adopting a reduced summer fungicide 
program, however, is more likely to be increased 
flexibility in time management and the ability to 
incorporate summer oils into the spray program 
without risking phytotoxicity from fungicide/oil in- 
teractions. In addition, it is possible that this prac- 
tice might be helpful for beneficial organisms in 
the orchard. 



^L ^U ^L •^L ^L 



16 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



On-farm IPM Education: 
Displays and Self-guided Tours 

Craig HoUingsworth, William Coli, and Ronald Prokopy 
Department of Entomology, University of Massachusetts 

Karen Hauschild 

Department of Plant & Soil Sciences, University of Massachusetts 



Returning from a 1995 international scientific 
conference, two of us toured the fruit growing re- 
gion of Switzerland. Among the techniques for 
educating the Swiss consumer about Integrated 
Fruit Production (the European version of IPM) 
that we observed were self-guided tours within 
vineyards. These tours consisted of signs and pic- 



tures which explained a variety of agricultural tech- 
niques in use in the vineyard. This spawned the 
idea of educating Massachusetts apple customers 
about IPM through similar orchard tours. 

Apple growers were solicited to participate in 
the project through announcements in extension 
publications and by phone. The nineteen growers 



VISUAL TRAPS attract early season pests 
such as apple sawtlies and leafininers by 
mimicking the attractive parts of the apple tree. 
Using these traps, a farmer can detennine 
whether pesticide applications are needed, 
eliminating unnecessary pesticide use. and 
often resulting in better quality fruit. 




Sawflies are attracted to apple 
blossoms, mimicked by white traps. 



Leafminers are attracted to reddish 
tree bark, mimicked bv red traps. 






Apple sawfly adult Sawfly damufie Leafminer adult Leafminer damage 





Trap for apple saw/ly Trap for leafminer adult 

Figure 1. A photograph of one of the signs in the self-guided tour. 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



17 



who responded provided assistance in determin- 
ing the content and design of the education dis- 
plays and contributed matching funds for a grant 
by the Massachusetts Department of Food &c Ag- 
ricuhure. It was determined that self-guided tours 
would the most appropriate for pick-your-own 
operations but that static sign-boards would be 
more useful for farmstands and farmers markets. 

Self-guided Tour 



trol, biological control and pesticide use, as well 
as the biology of primary apple pests. A colorful 
8-x-l 0-inch sign to advertise the tour was also in- 
cluded. 

At each orchard,, the grower determined how 
the signs were placed. Most were arranged through 
part of the orchard. In some cases, a path was 
marked by mowing or with plastic tape. It was 
suggested that IPM tools such as insect traps and 
scare-eye balloons be placed in association with 
appropriate signs. 



Each tour consisted of eight signs, 18 x 24 
inches, on laminated paper, mounted on 0.5-inch Apple IPM Displays 
plywood, covered with Plexiglas and sealed with 
plastic. Figure 1 is an example of one of these 
eight signs. Each sign was mounted on a 7-foot, 3- 
x-5-inch pressure-treated post. The signs describe 
aspects of IPM, including monitoring, cultural con- 



Self-standing displays were developed and dis- 
tributed to eleven Massachusetts farms for use at 
farmstands and farmers markets. Figure 2 is a 
photograph of one of the displays. Displays con- 




i 



NTr-C^iiTEO PEST MANAGEMENT 

,.ombi;iti di(fL-(ciu in(:tt,vds of [x-u 

rntrot to produce qn.ility fruit in an 

n onmcntaily rwponsiblc m,li>nc' 

■ [I'O fitJ'^.Tged tlirougli .1 cot'ibination 

, . mg, natural enemies, cuUtml 

, actices aod chemical coniroi 




riHTiJftAt AliVJ/lGf MrNT 



l« 




l^ 



M 




► 



L(ur.!ll/-0^..u'Hn>; iv.tJmo. 




>•!: 



i 



Figure 2. A photograph of the self-standing display. 



18 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



sisted of a three hinged panels of vinyl lattice mea- 
suring 4x8 feet. For strength and stability, each 
panel was framed with vinyl edging. Four lami- 
nated posters describing and illustrating apple IPM 
through the four seasons were hung on the frame- 
work. The displays could be folded for transport 
and were light enough to be carried by one person. 

Evaluation 

The self-guided tour was evaluated by a ques- 
tionnaire mailed to participating growers. Seven 
of the ten growers returned the questionnaire. 

Most growers (5 of 7) arranged the signs as 
tours within their orchards. Two growers placed 
all the signs in one place. Five of the seven grow- 
ers told their customers about the tour. No grow- 
ers provided extra signs to direct their customers 
to the tour. Four growers added traps and other 
IPM equipment to the tour. Positive comments 
from customers about the tour were received by 
four of the growers. Five growers reported their 
intentions to use the tour as part of their educa- 
tion program for school children. 

Growers reported that between 1% and 40% 
of their customers took the "tour". Two growers 
(with participation of 1% and 40%) rated this as 
"unsatisfactory." All growers reported that the 
message and information presented, presentation 
and workmanship were good to excellent. The 
over-all success of the project was rated good to 
excellent on six farms and poor on one farm. 

Both educational projects were also evaluated 
by a brief customer survey. Twenty-nine custom- 
ers at two farmstands with self-guided tours were 
surveyed, 30 at a farmstand with an IPM display, 
and 40 at two farmstands with neither educational 
program. 

Twenty-four percent of all customers professed 
to having heard of IPM before coming to any of 
the orchards. Where a self-guided tour was located. 



14% of customers interviewed had taken the tour, 
whereas, 60% of customers looked at available 
IPM displays. When asked to describe what they 
learned from a farmstand display, the most frequent 
response (37%) was that IPM uses less pesticide. 
Ninety-five percent (20 of 21 responses) of the re- 
spondents agreed that seeing this information af- 
fected their attitude about farming. Of these, 85% 
said that their attitude became more positive. Three 
individuals traveling together said that their atti- 
tude was more negative after viewing the display. 
We also evaluated the program by visiting farms 
where the tours and displays were used. It was 
apparent tours were less successful where custom- 
ers were not adequately informed that the tours 
existed, or where the start of the tour was too far 
from the farmstand. 

Conclusions 

Public education on farms can be especially 
effective in a pick-your-own setting. As customers 
indicated, families pick apples, in part, as a recre- 
ational activity, but once the apples are picked, they 
are looking for other things to do. 

These educational products were successful for 
some growers, but not for others. As with most 
educational or marketing products, they are tools 
and must be used in an appropriate manner to pro- 
duce the best results. Self-guided tours are best 
placed in a convenient, conspicuous location and 
promoted by the grower through welcoming 
signage, talking to customers, and other methods. 
Tours can become another reason for customers to 
come a particular farm. In this project, press re- 
leases attracted a number of customers. Static dis- 
plays are much simpler for the grower to use, and 
while they did not have the novelty or recreational 
value of the tours, it was clear that the message 
from simple signs reached a greater percentage of 
customers. 



*,L Kf^ ^L *.L *>?. 



Fruit Notes, Volume 63 (Number 4), Fall, 1998 



19 




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