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Fruit Notes
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
ISSN 0427-6906
LI'l
JAN 19 SO
UNIV. OF MASS.
BIOLOGY
Volume 55, Number 1
WINTER ISSUE, 1990
Table of Contents
The Brock Apple
Root Pruning of Apple Trees
Three Years of the Massachusetts Second-stage Apple
IPM Pilot Project: Blocks Receiving Apple
Maggot Fly Interception Traps
Three Years of the Massachusetts Second-stage Apple
IPM PilotProject: Blocks Receiving
Perimeter Row Sprays
Evaluation of Releases of Amblyseius fallacis
Predatory Mites on Apple Trees
Development of a Program for Grower and Consultant Education
and Certification in Integrated Pest Management
Effects of the Loss of EBDC Fungicides on IPM Programs in New England
Factors Affecting EBDC Fungicide Residues in Apple Fruit
Massachusetts Apple IPM Program: Observations in 1989
Fruit Notes
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Fruit Notes
Department of Plant & Soil Sciences
205 Bowditch Hall
University of Massachusetts
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COOPERATIVE EXTENSION POLICY:
All chemical uses suggested in this publication are contingent upon continued registration. These chemicals should be
used in accordance with federal and stale 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,
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DAMAGE
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and employment.
The Brock Apple
James R. Schupp
Highmoor Farm, University of Maine
Brock is a high quality dessert apple of the Jona-
gold type that is worthy of trial by New England
growers. Although not widely known, it has been a
popular gourmet apple in localized parts of Maine,
Ohio, and Oregon.
Origin
Brock resulted from a cross of Golden Delicious
and Mcintosh made at Highmoor Farm (Monmouth,
ME) in 1933 and was first designated as Me. 7-492.
After a long period of observation and tests, Russ
Bailey, the plant breeder at the University of Maine,
released it for public trial in 1966. The selection was
named Brock after Heniy Brock, an apple grower from
Alfred, ME who tested 7-492 in cooperation with the
University. The fruit of 7-492 became veiy popular
with consumers in the Alfred area who referred to it as
"Brock's apple."
Description
The Brock tree is vigorous and similar in appear-
ance to Golden Deli-
cious with a wider leaf
blade and redder bark.
Brock is productive
and crops annually if
chemically thinned.
The fruit ripen in early
October, with Deli-
cious, under Maine
conditions. The fruit
are uniformly large,
rounded conic, and
somewhat angular.
The stem is of medium
length and thickness
and the fruit hang well
prior to picking. The
skin is 30 to 90%
blushed with bright
red over a light yellow
ground color, with
prominent white len-
ticels (see Figure 1).
The flesh is
creamed-colored, firm,
crisp, juicy, and sub-
acid to sweet. The fla-
vor is very good, and in taste tests at the University of
Maine in the 1950's and 1960's, Brock was ranked as
good as or better than the cultivars to which it was
compared: Delicious, Golden Delicious, Northern Spy,
Mcintosh, Macoun, and Idared. More recently, Brock
has received rankings as high as or higher than Golden
Delicious and others in taste tests in Oregon (see
GoodFruit Grower May 1, 1989. pp. 44-45).
The core of Brock is unusually small, a desirable
feature for culinary use. Samples of Brock from
Highmoor Farm on October 4, 1989, yielded the follow-
ing characteristics: 7.6 ounces weight, 3.25 inches
diameter, 15.7 pounds flesh firmness, and 13.5% sol-
uble solids.
In summary, Brock is a high-quality, dessert-type,
blushed, golden apple that has been a successful addi-
tion to the limited markets in which it has been tried.
Growers interested in a Jonagold-class apple with
superior storability should test it on a trial basis. Trees
of Brock are available from a few nurseries and scion
wood for budding or grafting is available from
Highmoor Farm.
Fruit Notes, Winter, 1990
Root Pruning of Apple Trees
James R. Schupp
Highmoor Farm, University of Maine
In 1989, the public furor over Alar™ effectively
eliminated the use of that chemical by apple growers.
This left a substantial number of growers looking for
alternatives to Alar as a means of reducing tree growth,
reducing preharvest drop, and improving fruit color
and fruit quality. Mechanical root pruning is one
option that some growers considered.
Root pruning has been studied in some detail at the
Ohio Agricultural Research and Development Center
since 1982, and at the University of Maine since 1988.
The results of these research efforts are summarized
here and are used to make the recommendations that
follow.
Effects on Bearing Trees
Table 1 contains a list of the effects of root pruning.
To summarize, root pruning of bearing apple trees
reduces the total growth of the tree. This growth
suppression is season-long, thus pruning time is re-
duced. Fruit set is not affected, so the net effect is a
smaller tree with just as many apples. Fruit size is
reduced, while fruit color, firmness, and sugar content
are increased. Preharvest drop is reduced.
Effects on Non-Bearing Trees
The effects reported above are for bearing trees. If
the trees have little or no crop, either from frost damage
or because of alternate bearing, the effects will be much
less dramatic. For example, in one of our studies in
Ohio, root pruning reduced vegetative growth in bear-
ing trees by over 40%, while the reduction in growth in
non-bearing trees was only 14%. Studies with young,
potted trees showed that such trees needed root prun-
ing twice in one season to achieve season-long reduc-
tions in growth, even when the pruning was quite
severe. Pruning the roots of non-bearing trees in the
orchard more than once in a single season has not been
tried and the possible benefits, as well as the possible
problems, are not known.
When and How?
All these effects are dependent on timing. The best
time to root prune is from bloom until two weeks later.
Pruning too late will increase preharvest drop instead
of reducing it and will not reduce the growth of the tree
in that season.
Root pruning is done with a sharpened subsoiling
blade mounted on a tool bar such that it extends out
beyond the right rear tire of the tractor. The 3-point
hitch, attachment pins, and tool bar should be heavy-
duty. A chain or cable extending to the front axle lends
stability to the offset blade. Tractors in the 40 to 50
horsepower class have proven satisfactory, however
the blade cuttingthrough the soil has a tendency to pull
the tractor into the tree row, particularly the first
season the treatment is applied, and especially if the
cutting depth is greater than 12 inches. Our studies
have shown that pruningto a 12-inch depth is adequate
to produce the desired effect, but if a grower wants to
prune deeper, or if the going is tough even at a 12-inch
depth, the steering problem can be corrected by: a)
running two tractors in tandem; or b) pruning the roots
once at a shallow setting, then going back through the
original cut a second time to the final depth. Root
pruning in heavy sod is much more difficult than in a
herbicide strip and almost always will require a second
pass to finish the job.
In order to take effect, root pruning must be done
on both sides of the row, to a depth of 12 inches. The
amount of vegetative growth control can be adjusted
somewhat by adjusting the distance from the cuts to
the trunk. Root pruning of overly vigorous Melrose/
M.26 trees at 24 or 32 inches from the trunk produced
dramatic reductions in growth. In Maine, I have ob-
tained satisfactory results on Mclntosh/MM.lll trees
pruned on 2 sides at 40 inches from the trunk and to a
depth of 12 inches.
What Can Go Wrong?
In addition to the problems of the blade pulling the
tractor into the tree row and the difficulty in root
pruning through thick sod, there are some things that
can go wrong. Low, hanging limbs get scraped up
badly, and if they are large, they will present an effec-
tive barrier to progress down the row. Long overhang-
ing limbs that stick out into the drive row can make the
tractor driver feel as persecuted by apple trees as was
Dorothy in The Wizard ofOz.
If there are large roots just under the surface,
occasionally one will catch on the blade instead of
cutting cleanly. When this happens the root will be
pulled off the tree and often a good chunk of the bark on
the trunk will be stripped away with it. Dave Ferree
Fruit Notes, Winter, 1990
Table 1. Effects of root pruning on apple tree growth and yield.
Parameter
Increased
Decreased
No change
Trunk growth
X
Shoot length
X
Shoot number
X
Spur/shoot ratio
X
Shoot leaf size
X
Spur quality
X
Pruning time
X
Canopy light penetration
X
Return bloom
X*
Fruit set
X
Fruit yield (no. of fruit)
X
Fruit size
X
Preharvest drop
X
Fruit color & quality
X
Tree yield efficiency
X
•Increased return bloom from root
pruning has been reported widely, but has
not been noted in studies conducted by the author.
and I first observed this occurrence in an orchard with
sandy soil. Apparently the sand yielded to the pulling
effect when cutting thick roots, because out of the
several hundred that we root pruned that day, we
damaged two trees in this way. Large rocks directly in
the path of the blade must be negotiated over or
around, much as is the case when planting trees with a
tree planter.
Should You Root Prune?
Growers get paid better for growing big apples
than smaller apples. Not only does a box of big apples
command a higher price, but it does not contain as
many fruit. To a researcher who has worked on root
pruning as long as I have, this system of financial
reward seems dreadfully unfair; nevertheless, it is a
reality. On the other hand, if the big apple cannot make
grade because it cannot meet the minimum standard
for color or if it loses its firmness and storability hang-
ing on the tree while its owner waits for color, or if it
falls to the ground before it can be picked, then root
pruning might have a place. The savings in pruning
time can be significant; in my research plots, root-
pruned trees took 12
minutes each while
trees that were not root-
pruned required 20
minutes each for dor-
mant pruning. Re-
duced pruning time,
improved fruit color
and quality, and re-
duced preharvest drop
are the benefits. The
reduced fruit size is the
cost. The economics of
each situation need to
be considered carefully.
Often, apple grow-
ers have three kinds of
trees on their land:
blocks of large trees on
seedling rootstocks,
blocks of mature, semi-
dwarf trees, and blocks
of more recently
planted small trees.
The small trees are
coming into production,
the seedling trees are scheduled for removal, and the
semi-dwarf trees will have to remain for another 10
years to provide some cash flow and pay the bills. If the
fruit qualify and preharvest drop in part of the semi-
dwarf blocks are unacceptable and the trees are too
vigorous, then the costs and benefits of root pruning
should be weighed. If the tree spacing is too close and
hard, containment pruning is necessary, then root
pruning may be a real boon. On the other hand, if tree
vigor is moderate and a little summer pruning is all
that it takes to get red apples, then root pruning is un-
necessary.
If an apple grower has blocks of trees with exces-
sive tree size and vigor and can afford to replace them
right now with dwarf trees, then root pruning is a step
backward.
Root pruning is a highly effective method of con-
trolling tree growth and improving fruit quality. Be-
fore root pruning acres of apples, talk things over with
your local fruit specialists and researchers. If it is
possible, take the long-term solution-replant with
trees on the appropriate size-controlling rootstocks at
the appropriate spacing.
»$» •{» «.% *}* »S*
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Fruit Notes, Winter, 1990
Three Years of the Massachusetts
Second-stage Apple IPM Pilot Project:
Blocks Receiving Apple Maggot Fly
Interception Traps
Ronald J. Prokopy, Margaret Christie, Katharine Rankin, and
Cheryl Donovan
Department of Entomology, University of Massachusetts
One year ago in Fruit Notes [54(l):l-5], we re-
ported our results of the first two years (1987, 1988) of
our second-stage apple IPM pilot project in Massachu-
setts commercial orchards. Second-stage IPM employs
behavioral, ecological, and biological approaches to
pest management as a substitute for all insecticide and
miticide treatments after the last spray against plum
curculio in early June. The intent of second-stage IPM
practices is not only to provide an environmentally
safe, cost-effective approach to controlling summer
pests that directly attack apple fruit (apple maggot,
codling moth, summer leafrollers) but also to alleviate
insecticide and miticide toxicity to beneficial predators
and parasites of important foliar pests such as mites,
aphids, leafminers, and leafhoppers. Allowing more
natural enemies of foliar pests to flourish reduces the
need for pesticide treatment against foliar pests and
thereby lessens the rate (currently high) at which these
pests are developing resistance to pesticides. To em-
phasize further this latter goal, a major facet of second-
stage IPM is use, during April, May, and June, of
pesticides leastlikely to be harmful to beneficial preda-
tors and parasites.
From a veiy real and timely, practical point of view,
under current strong public pressure to reduce pesti-
cide use on apples, perhaps one of our best hopes for
minimizing the risk of there being detectable pesticide
residues on apples at harvest lies in implementing the
philosophy and practices of second-stage IPM. This
philosophy of no insecticide or miticide spray on apples
after early June should be highly appealing to environ-
mentalists, legislators, public health officials, and con-
sumers. The big question is: can high quality fruit be
produced economically year after year under this phi-
losophy?
Over the 3 years of our pilot project (1987-1989),
we have compared 2 different non-pesticidal ap-
proaches to implementing second-stage IPM philoso-
phy. The essential difference between the two lies in
the techniques used for intercepting apple maggot flies
(a key summer pest) before flies can penetrate the
orchard interior during their movement toward or-
chards from abandoned host trees hundreds of yards
away. The techniques are: (1) placing synthetic-apple-
odor-baited sticky red sphere traps every 10 yards
(1987) or every 5yards (1988, 1989) on perimeter apple
trees and (2) spraying perimeter (border row) apple
trees every 3 weeks from late June through August.
For both approaches, we aimed to control codling
moths and summer leafrollers by removing (in May,
1987) all abandoned apple trees within 100 yards of the
orchard block perimeter to preclude immigration of
fruit-seeking female moths. Each approach has been
carried out over the 3-year pilot period in 6 commercial
orchard blocks, averaging 2 to 3 acres each. Each test
block has been matched with a nearby block of compa-
rable size that was treated during June, July, and
August under first-stage IPM practices.
Here, we report results of the technique using
apple maggot fly interception traps. In a companion
article, we report results of the technique using pe-
rimeter row sprays.
Apple Maggot
Data in Table 1 show that each year, very large
numbers of apple maggot flies were captured on the
interception traps in the second-stage IPM blocks
(range of 2,054 to 3,180 flies per block per year). In our
judgement, this level represents an enormous amount
of potential maggot fly pressure on the crop. Even so,
a 3-year average of only 46% more flies was captured on
nonbaited monitoring traps at the interior of second-
stage compared with first-stage blocks. This reveals
the power of the traps in preventing fly immigration
into the block interior.
Fruit Notes, Winter, 1990
Table 1
Average number of apple maggot flies captured per
block
Year
Block
Perimeter-row
interception traps*
Interior
monitoring traps**
1987
1988
1989
Second-stage
First-stage
Second-stage
First-stage
Second-stage
First-stage
2,054
3,021
3,191
123
84
117
105
112
52
*Apple-odor-baited interception traps placed every 10 yards (1987) or every 5 yards
(1988, 1989) on perimeter apple trees.
**Four non-baited traps on interior apple trees.
Data in Table 2 reveal the average amount of fruit
injury caused by all insect pests active after mid-June.
Over the 3 years, apple maggot injury decreased from
1.4 to 0.5 to 0.3% in the second-stage blocks. The
average of 0.4% maggot injury over 1988 and 1989 in
these blocks was comparable with the average of 0.2%
maggot injury in the first-stage IPM blocks. These data
show that the interception trap approach is very little
different from insecticide sprays in ability to provide a
commercially acceptable very high level of maggot- free
fruit (0.5% or less maggot injury).
Codling Moth
Data in Table 2 also show that the method of
removing all apple trees within 100 yards of the or-
chard perimeter was as effective as a standard first-
stage program in preventing codling moth injury to
fruit. Apparently, sprays against plum curculio in late
May and early June pro-
vide excellent control of
any first-generation cod-
ling moth eggs that might
have been laid, while the
distance of 100 or more
yards from the orchard
perimeter is too great to
be overcome by potential
second-generation cod-
ling moth immigrants in
July and August. We are
initiating a field test to
determine whether re-
moving all apple trees
within 50 yards of the
orchard perimeter
achieves the same high
level of codling moth disruption as removing all apple
trees within 100 yards.
Leafrollers and Lesser Appleworm
In our judgement, the greatest potential threat to
future success of second-stage IPM practices lies in
buildup of summer leafrollers and lesser appleworms.
These pests have begun to build up substantial toler-
ance to several types of insecticides in recent years in
New York and apparently also in a few Massachusetts
orchards. Hence, the problem of increasing fruit dam-
age from leafrollers and lesser appleworms seems to be
a general one in the Northeast.
As shown in Table 2, in 1989 combined leafroller
and lesser appleworm damage in second-stage IPM
blocks averaged slightly greater than in first-stage
blocks (1.7 versus 1.1%). These pests have a much
broader host range and may be more mobile than
Table 2.
Average percent fruit
injury by insect
pests active after mid-J
une.***
Other
All
Year
Block
AMF
CM
RBLR
LR
LAW
other
Total
1987
Second-stage
1.4
0.0
0.1
0.0
1.5
First-stage
0.7
0.0
0.0
—
—
0.1
0.8
1988
Second-stage
0.5
0.0
0.1
—
-
0.0
0.6
First-stage
0.2
0.0
0.2
—
—
0.0
0.4
1989
Second-stage
0.3
0.0
0.1
1.2
0.4
0.2
2.2
First-stage
0.2
0.1
0.2
0.6
0.3
0.0
1.4
*500 on-
tree fruit sampled per
block during July, August,
and September.
**AMF
= apple maggot; CM
= codling moth
RBLR =
red banded leafroller;
other LR =
= other unidentified
leafrollers; LAW = lesser appl
sworm.
Fruit Notes, Winter, 1990
Table 3. Trap captures and larval injury in blocks receiving mass application of sex pheromone
to disrupt mating of red banded leafroller and lesser appleworm moths in 1989.
Total no. males
captured in
% Larval injury
Pest
Orchard
Block
pheromone traps*
to fruit at harvest**
Red banded
A
Pheromone trtd***
28
0.0
leafroller
Grower sprayed
471
0.5
Red banded
B
Pheromone trtd***
4
1.0
leafroller
Grower sprayed
268
2.5
Lesser
C
Pheromone trtd***
10
0.5
appleworm
Grower sprayed
123
0.5
Lesser
B
Pheromone trtd***
35
5.5
appleworm
Grower sprayed
530
4.5
*Total-season captures of males in 5 monitoring traps per block.
**Based on 200 fruit sampled per block at harvest. Most sampled fruit were doubles (stems
closely opposing one another).
* * *Treated with 400 pheromone dispensers per acre on April 20 and August 1 (for red banded),
or on May 19 and August 2 (for appleworm).
codling moths, so that it might be necessaiy to remove
a wide variety of plants over long distances from the
orchard perimeter to preclude immigration of larvae
(blowing in on threads of silk that they spin) or of
females. Even then, this approach may not succeed
because of the ability of several of these pests to tolerate
pesticides used against plum curculio. Thus, unlike the
situation with codling moth, early-season leafrollers
and lesser appleworms may not be completely elimi-
nated from the orchard interior by early season pesti-
cides directed against plum curculio.
The best future hope for managing leafrollers and
lesser appleworms under second-stage IPM principles
may lie in one of two practices: (1) application of
Dipel™ (bacteria that produce compounds toxic to
lepidoptera) or Dimilin™ (an insect growth regulator)
at the time when first-generation larvae are active
(early May to early June) or (2) application of synthetic
sex pheromone to disrupt mating and deposition of
fertile eggs. In collaboration with Bicontrol LTD of
Queensland, Australia, in 1989 we evaluated season-
long use of mating disruption pheromone against red
banded leafrollers and lesser appleworms in 3 commer-
cial orchard blocks not sprayed with insecticide after
early June. Compared to nearby first-stage IPM
blocks, there was a very strong reduction in captures of
male moths in pheromone traps in the pheromone-
treated blocks (Table 3). This result illustrates the
power of mass application of pheromone to prevent
mate-seeking males from locating sources of female
pheromone released in the traps. Presumably the
males are similarly prevented from finding living fe-
males in the orchard. However, there was only a
moderate reduction of red banded leafroller fruit injury
and no reduction of lesser appleworm injury in the
pheromone-treated blocks (Table 3). Failure to obtain
good control of larvae in the pheromone-treated blocks
may have been due to immigration of fertile females or
larvae (blowing in on silken threads). More in-depth
orchard research is needed before a mating-disruption
approach to control these pests becomes feasible.
Foliar Pests and Their Natural Enemies
Data in Table 4 show that in all years where
sampled, predatory mites, aphid predators, and
leafminer parasitoids were more abundant in second-
stage than in first-stage IPM blocks. On the other
hand, averaged over the 3 years, pest mites, apple
aphids, and leafminers were no more abundant in
second-stage than in first-stage blocks, despite no pes-
ticide treatments against these pests after early June in
the second-stage blocks. Similarly, woolly apple aphids
and potato leafhoppers were essentially no more evi-
dent in second-stage than first-stage blocks across the
3 years. In 1987 and 1988, white apple leafhoppers
were considerably more abundant in second-stage
than first-stage blocks. In 1989, use of endosulfan in
Fruit Notes, Winter, 1990
Table 4.
Average percent
leaves
(or term
inals) harboring foliai
pests or beneficial natural enemies.*
.**
Ratio of
Year
Block
ERMor
TSM AF
YM
pest to
predatory
mites
WAA WAL
PL
ABLM
ABLM PAR
GAA GAAP
1987
Second-stage
20
4.0
3.2
3:1
2 9
17
10
..
First-stage
13
1.5
2.3
4:1
2 5
10
14
..
1988
Second-stage
12
1.3
1.2
5:1
3 27
3
11 35
14 6.7
First-stage
11
1.1
0.1
9:1
4 18
2
11 23
16 3.7
1989
Second-stage
22
3.0
0.3
6:1
3 2
5
5 49
32 30.7
First-stage
24
2.3
0.1
10:1
3 1
4
6 35
35 27.8
*400 leaves (or terminals) sampled per block during July, August, and September.
**ERM = European red mites; TSM = two spotted mites; AF = predatory Amblyscius fallacis; YM = predatory
yellow mites; WAA = woolly apple aphid; WAL = white apple lcafhopper; PL = potato leafhopper;ABLM = apple
blotch leafmincr; ABLM PAR = percent parasitized leafmines of second generation; GAA = green apple aphid;
GAAP = green apple aphid predators (cccidomyiids and syrphids).
late May or early June against leafhoppers in problem
blocks provided good control and alleviated this poten-
tial problem.
Pesticide Use Patterns
Data in Table 5 show the average number of insec-
ticide and miticide treatments per block from April to
early June and from early June onward. On average,
each block type received 1.4 sprays of oil, 3.9 sprays of
insecticide, and 0.2 sprays of miticide from April to
early June. Thereafter, the second-stage blocks re-
ceived no insecticide or miticide, while the first-stage
blocks received an average of 2.8 insecticide and 1.5
miticide sprays. Overall, second-stage blocks received
only 58% as many insecticide sprays and 12% as many
miticide sprays as first-stage blocks. Compared with
non-IPM apple pest management practices of the mid-
1970's, second-stage blocks received only 37% as many
insecticide sprays and 10% as many miticide sprays
(exclusive of oil).
Cost Analysis
Estimated costs per acre of first-stage versus sec-
ond-stage IPM practices employing apple maggot
interception traps are given in Table 6. Average annual
per acre costs over the 3 years were nearly identical for
both practices: $190 versus $186, respectively. Thus,
even under the labor-intensive practice of stickying,
Table 5.
Average number of insecticide ;
ind miticide treatments pe
r block.
Pre-bloom
Insecticide
Miticide
April to
Early June
April to
Early June
Year
Block
oil
early June
onward
early June
onward
1987
Second-stage
0.8
4.5
0.7
0.0
First-stage
0.8
4.3
2.2
0.7
1.6
1987
Second-stage
1.5
3.5
First-stage
1.5
3.5
3.1
1.7
1989
Second-stage
2.0
3.8
First-stage
2.0
3.8
3.2
1.2
Fruit Notes, Winter, 1990
Table 6. Partial analysis of estimated cost (dollars) per acre per year of first-stage
versus second-stage IPM practices for insect and mite control (averaged over all 3
years).
First-stage
Second-stage
Control method
IPM
IPM
Pre-bloom oil*
$19
$19
Insecticide*:
April to early June
$77
$78
Early June onward
$57
$0
Miticide*:
April to early June
$5
$5
Early June onward
$32
$0
Cutting down abandonee
apple trees**
$0
$2
Purchase, emplacement,
periodic
cleaning, and removal of
apple
maggot traps***
$0
$82
Total
$190
$186
*Materials plus application costs.
**Pro-ratcd over 10 years.
***Includes initial cost of $80 (pro-rated over 10 years at $8/year) for purchase of
traps, $2/year for tangletrap, $10/year for purchase of vials and attractive odor
(both new each year), and $62/year for 10 hours of labor required to sticky-coat,
emplace, clean (3 times), and remove the traps.
emplacing, and cleaning the apple maggot traps, sec-
ond-stage IPM was no more expensive than first-stage
IPM. Replacement of sticky spheres by pesticide-
treated spheres should lower the cost of future second-
stage IPM application dramatically.
Conclusions
Overall, we are extremely encouraged by the re-
sults of 3 years of implementation of second-stage IPM
practices involving use of interception traps against
apple maggot flies in the 6 commercial apple orchard
test blocks. Fruit injury by apple maggot and codling
moth has stabilized at a veiy low level. Beneficial
predators and parasitoids have begun to flourish and to
provide good control of major foliar pests (although,
leafhoppers may be an exception). Fruit quality at
harvest, as evidenced by our systematic sampling of
injury levels and asjudgedby cooperating growers, has
been excellent. Second-stage blocks received only a bit
more than half as many insecticide sprays and a tenth
as many miticide sprays as first-stage blocks. Second-
stage practices were no more expensive than first-stage
practices, even under the labor-intensive effort associ-
ated with using sticky apple maggot traps.
We believe, however,
that there are 3 key areas to
be addressed before we can
recommend confidently
second-stage IPM practices
for widespread use. The
first is development of a
substitute for sticky (which
is too messy to handle on a
large scale) as the agent
controlling apple maggot
flies alighting on apple-
odor-baited red sphere
traps. Our progress in
developing such a substi-
tute (pesticide treated
spheres) will be reported in
a separate Fruit Notes ar-
ticle. The second is mainte-
nance of summer leaf-
rollers and lesser apple-
worms at a low level in sec-
ond-stage IPM orchards.
For this purpose, we need
further work on the poten-
tial value of using Dipel or
Dimilin in early season
sprays, and on employing
mating disruption phero-
mone. The third is picking up all drops shortly after
harvest. If drops were not removed before decay set in,
larvae of apple maggot, lesser appleworm, codling
moth and some leafrollers would have the opportunity
to remain and develop to overwintering maturity.
There would be within-orchard buildup of these pests,
threatening next year's crop. This buildup would
negate the value of attempting to manage these pests
by preventing their immigration into the orchard. The
loss of Alar™ and the consequent greater number of
apple drops makes this job more difficult.
If the EPA would approve general use of an odor-
baited, pesticide-treated-sphere system of controlling
apple maggot flies, if apple drops were faithfully picked
up shortly after harvest, and if we could contain dam-
age by summer leafrollers and lesser appleworms at a
low level, then growers should be able to employ sec-
ond-stage IPM practices with high confidence. Grow-
ers and the public alike would benefit from a healthier
orchard environment.
Acknowledgements
We thank the Massachusetts Society for the Pro-
motion of Agriculture, the Northeast Regional Project
on Integrated Management of Apple Pests (NE-156),
8
Fruit Notes, Winter, 1990
and the joint federal/state apple IPM project for sup-
porting our work on second-stage apple IPM in 1989.
We also thank Kathleen Leahy, Dave Stanley, and
Patti Powers for their assistance in sampling orchards,
and Roy Van Drieschefor determining leafminer para-
site levels.
«f* *% *f# *% *3a
rj» #J» #J% «J* »J%
Three Years of the Massachusetts
Second-stage Apple IPM Pilot Project:
Blocks Receiving Perimeter Row Sprays
Margaret Christie, Cheryl Donovan, Katharine Rankin, and
Ronald Prokopy
Department of Entomology, University of Massachusetts
In the preceding article, we describe the rationale
and principles of second-stage apple IPM strategy and
tactics. We outline in that article two approaches to
achieving the second-stage IPM goal of greatly reduc-
ing or eliminating use of insecticide and miticide after
May. One principal distinction between the two ap-
proaches lies in the tactic used for managing apple
maggot flies: use of traps on perimeter apple trees to
intercept immigrating apple maggot flies before they
can penetrate the orchard interior versus spraying of
perimeter-row apple trees eveiy 3 weeks from June
through August to prevent flies from penetrating the
orchard. Here, we present a summary of 3 years of
implementation of the latter approach in 6 commercial
orchard test blocks.
Methods Used
The second-stage IPM test blocks averaged 2 acres
in size and were compared with adjacent blocks of
similar varietal composition and size, treated under
first-stage IPM practices. Each year, both types of
blocks were sprayed in essentially identical fashion
from April to early June. Thereafter, the first-stage
blocks received pesticide throughout the block when
pest monitoring information indicated a need for such,
while the second-stage blocks usually received insecti-
cide every 3 weeks on both sides of all perimeter apple
trees but no insecticide (or miticide) on the block
interior. In addition, all apple trees within 100 yards of
the perimeter of each second-stage orchard block were
removed in May of 1987 to discourage immigration of
codling moths and summer leafrollers.
Results
Data in Table 1 show levels of pest captures on
monitoring traps and levels of pest injury to fruit. Over
the 3 years, 74% more apple maggot flies were captured
on nonbaited monitoring traps at the interior of sec-
ond-stage than first-stage blocks. This represents a
greater capture-level difference between first- and
second-stage blocks than where apple maggot intercep-
tion traps were employed on perimeter- row apple trees
(see preceding article). This result suggests that the
interception trap approach may be more effective than
the perimeter-row spray approach for intercepting
apple maggot flies.
Apple maggot damage averaged about the same in
perimeter- row-sprayed and first-stage IPM blocks over
1987 and 1988, but in 1989 it was considerably greater
in the perimeter-row-sprayed blocks (1.2 versus 0.1%).
No codling moth or lesser appleworm injury to fruit
was found in any block in any year. Leafrollers caused
very little fruit damage in either type of block in 1987
and 1988 (0.1% or less) but in 1989 damage climbed to
0.3% in first-stage blocks (versus 0.1% in second-stage
blocks). All other insects remained at a very low level
throughout the study (0.2% damage or less).
Data in Table 2 show levels of foliar pest mites and
Fruit Notes, Winter, 1990
Table 1
Average percent fruit injury bj
' insect
pests active after mid-June.*-**
Avg. percent of fruit injured by
insect
pests
Avg. number of
ami? „« :„+„..:„„
active after mid-June
monitoring
Other
All
Year
Block
traps
AMF
CM
RBLR
LR LAW
other
Total
1987
Second Stage
104
0.6
0.1
.
0.2
0.9
First Stage
63
0.8
0.1
-
0.1
1.0
1988
Second Stage
101
0.3
0.1
-
0.0
0.4
First Stage
53
0.2
0.0
-
0.0
0.2
1989
Second Stage
54
1.2
0.0
0.3
0.1
1.6
First Stage
33
0.1
0.0
0.1
0.0
0.2
*500 on
-tree fruit sampled per block during July, August, and September.
**AMF
= apple maggot;
CM = codling moth; RBLR =
red banded leafroller; other LR
= other
unidentified leafrollers; LAW = lesser appleworm.
Table 2.Average percent leaves (or terminals) harboring foliar pests or beneficial natural enemies.*'
Year
Block
ERM
TSM
AF YM
Ratio of
pest to
predatory
mites
WAA WAL PL ABLM GAM GAAP
1987
1988
1989
Second-stage
First-stage
Second-stage
First-stage
Second-stage
First-stage
24
16
12
10
24
23
1.2
0.3
0.3
0.5
3.6
2.5
0.1
0.0
0.1
0.1
0.1
0.0
19:1
48:1
30:1
17:1
7:1
9:1
5
5
5
5
10
8
1
8
6
1
1
9
10
2
2
1
1
5
4
4
6
6
6
31
23
59
55
11
8
47
50
*400 leaves (or terminals) sampled per block during June, July, August, and September.
"ERA = European red mites; TSM = two spotted mites; AF = predatory Amblyseius fallacis; YM = preda-
tory yellow mites; WAA = woolly apple aphids; WAL = white apple leafhopper; PL = potato leafhopper;
ABLM = apple blotch leafminer; GAA = green apple aphid; GAAP = green apple aphid predators:
cecidomyiids and syrphids.
their principal natural enemies. Each year pest mites
averaged greater in abundance in second-stage than
first-stage IPM blocks. The difference was substantial
in 1987 (50% greater pest mites in second stage blocks)
but narrowed to only 4% greater in 1989. Predatory
Amblyseius fallacis mites averaged greater in second-
stage than first stage blocks in 1987 and 1989 but the
reverse was true in 1988. Predatory yellow mites were
very few in number in any block in any year. The
overall ratio of pest to predatory mites was unfavorable
for effective biological control in either type of block in
1987 and 1988 (never more favorable than 17 to 1) but
was favorable for moderately effective biological con-
trol in both types of blocks in 1989 (7 or 9 to 1).
Data in Table 2 also show levels of other foliar pests
and natural enemies. There was very little or no
difference between block types in any year in popula-
tion levels of woolly apple aphids, white apple leafhop-
pers, potato leafhoppers, or apple blotch leafminers.
Likewise, there were no consistent or appreciable dif-
10
Fruit Notes, Winter, 1990
Table 3. Average number of insecticide and miticide treatments per block.
Insecticide
Miticide
Year
Block
Pre-bloom April to Early June April to Early June
oil early June onward early June onward
1987
1988
1989
Second stage
First stage
1.2
1.3
Second stage
First stage
1.7
1.7
Second stage
First stage
1.7
1.7
3.8
4.0
3.2
3.2
3.8
3.8
3.0*
2.5
2.7*
3.2
2.8*
3.3
1.3*
2.7
0.8*
2.0
0.3*
1.3
•Treatments applied only to perimeter apple trees - not to block interior.
ferences between blocks in levels of apple aphids or
aphid predators.
With respect to frequency of insecticide and miti-
cide use, from April to early June, on average over the
3years, both first- and second-stage blocks received 1.5
oil sprays, 3.6 insecticide sprays, and miticide sprays
(Table 3). Thereafter until harvest, first-stage blocks
received on average 3.0 insecticide sprays and 2.0 miti-
cide sprays. Second-stage blocks received (on perime-
ter trees only) an average of 2.8 insecticide and 0.8
miticide sprays (Table 3). Average annual per acre
costs of oil, insecticide, and miticide treatments over
the 3 years were about $194 for the first-stage blocks,
versus about $110 for the second-stage blocks. When
determining cost of treating second-stage blocks from
early June onward, we estimated perimeter trees as
comprising about 25% of an assumed rectangular 2-
acre block of M.7 trees (225 trees per block).
Conclusions
In conclusion, we generally are pleased with the
results of this perimeter-row spraying approach to
achieving the second-stage apple IPM aim of keeping
the interior of apple orchard blocks free of insecticide
and miticide sprays after early June. Fruit injury by
codling moths, lesser appleworms, and leafrollers was
absent or in low amount. Foliar pests such as leafhop-
pers, aphids, and leafminers were essentially no more
abundant in second-stage than first-stage blocks.
Annual insect and mite control cost only about 60% as
much in second-stage as in first-stage blocks.
We are somewhat cautious, however, with respect
to long-term effective control of apple maggot and
mites using this approach. In 1989, apple maggot
injury was considerably more pronounced than in 1987
or 1988 in second-stage blocks or than in any year in
first-stage blocks. In contrast, apple maggot injury
progressively declined from year to year under the
second-stage IPM approach of using odor-baited visual
traps on perimeter apple trees to capture maggot flies
(see preceding article). The reason for the sharply
increased average level of maggot injury in 1989 in
perimeter-sprayed blocks is unclear, but could reflect
greater buildup of apple maggot flies within orchards
as a consequence of greater fruit drop in the absence of
Alar™. If so, then a perimeter-row spray approach to
controlling apple maggot maybe reliable only in blocks
where drops of early- and mid-ripening cultivars are
picked up at harvest to prevent maggots maturing in
them. With regard to mites, in no year did the average
ratio of pest mites to predator mites in perimeter-
sprayed second-stage blocks reach as low as 5 to 1,
which is considered favorable for effective biological
suppression of pest mites. The ratio always exceeded 7
to 1 and was never as favorable as in second-stage
blocks receiving apple maggot traps rather than sum-
mer insecticide treatment on perimeter apple trees
(see preceding article). Perhaps a substantial propor-
tion of predatory mites is immigrating on wind into
orchards from plants surrounding the orchard and
perhaps these predators are affected by pesticide treat-
ment of border rows.
As a final word, we now believe that we can recom-
mend with reasonable confidence the value of a pe-
rimeter-row spray approach as a transitional step
Fruit Notes, Winter, 1990
11
aimed at managing apple insect and mite pests without Ackowledgements
use of insecticide and miticide after early June. Even
so, we believe that this aim will be more fully achieved
at eventual lower cost by adopting the second-stage
IPM practices set forth in the preceding article.
We thank the Massachusetts Society for the Promotion
of Agriculture and the Joint federal/state apple IPM
project for supporting our work on second-stage apple
IPM in 1989. We also thank Kathleen Leahy, Dave
Stanley, and Patti Powers for their assistance in sam-
pling orchards.
*Ta %?* fcf.» a.% %f#
*4» +%* rj> cj% 0fm
Evaluation of Releases of Amblyseius fallacis
Predatory Mites on Apple Trees
Ronald J. Prokopy and Margaret Christie
Department of Entomology, University of Massachusetts
David Stanley
Biokon Insectaries
One of the major aims of apple IPM is to promote
predatory mites as a substitute for chemical miticides
to control European red mites and two-spotted spider
mites. We envision 2 major methods of promoting
predatory mites: (1) using second-stage IPM practices
of non-use after early June of any pesticide even
slightly harmful to predatoiy mites (this includes vir-
tually all insecticides and miticides currently labelled
for orchard use, and some fungicides, especially beno-
myl and mancozeb) or (2) release into orchards of
laboratory-cultured predatoiy mites that have been
selected to resist major types of insecticides, such as
organophosphate and carbamate compounds. The
first option may be the less expensive one, but resident
or immigrating predatoiy mites could still be adversely
affected by early-season pesticide use. Here, we report
on 2 years of experiments in commercial orchards
evaluating the second option.
Methods Used
In 1988, we selected 2 experimental blocks (each
about 1 acre) in each of 6 commercial orchards. One
block (the first-stage IPM block) was treated normally
by the grower, using the first-stage IPM practice of
applying pesticide when pest monitoring information
indicated the need to do so. The second block (the
second-stage IPM block) was treated identically to the
first-stage block through early June. Thereafter, each
second stage block received only a border row spray ap-
plication of insecticide on perimeter apple trees every
three weeks until harvest. No insecticide or miticide
was applied to the second-stage block interior after
early June. For essentially all blocks, only Imidan™ or
Guthion™ as insecticide was applied after early June.
This protocol was followed in both 1988 and 1989.
In 1988, we released in July approximately 500
adults of the predatory mite Amblyseius fallacis under
each of 7 trees per block in both first-stage and second-
stage blocks in all 6 orchards. In 1989, we tripled the
number of A fallacis released in July to reach a level of
about 1 500 per each of 7 trees per block in both types of
blocks. However, they were released on tree foliage
rather than on the ground (as done in 1988), and were
released in only 4 of the 6 orchards. The predators
originated from a strain in Geneva, New York that has
been determined to be resistant to most organo-
phosphates, and possibly also to some carbamate insec-
ticides. The predators were cage-reared on two-spot-
ted mites cultured on bean leaves. Predators were
harvested by removing infested leaves from the cages.
Then a rough count of adult predators was made, after
12
Fruit Notes, Winter, 1990
which predators and the bean leaves were mixed with
cool, damp bran as a spreading medium. The mixture
was gently but thoroughly turned by hand before deliv-
ery to orchards where it was applied under or upon the
canopy of apple trees. Releases were timed to coincide
with the time when 20 to 40% of the leaves in the first-
stage and second-stage blocks were infested with pest
European red mites or two-spotted mites. We rea-
soned that releasing predators in a block with too few
pest mites (less than about 20% of leaves infested)
might stimulate the predators to leave the block and
search elsewhere for more abundant prey. If pest mites
were allowed to build beyond about 40% of leaves
infested, released predators might not be able to pro-
vide effective suppres-
sion. Foliage was
sampled for presence of
pest and predatory
mites in June (before
predators were re-
leased), in July (shortly
after predators were
released), and again
once each in August
and September. In an
attempt to control the
possibility that A falla-
cis appearing in the
aforementioned first-
and second-stage IPM
blocks might have been
progeny of resident A
fallacis (present before
the releases occurred)
or were natural immi-
grants from outside the
blocks, we compared
the numbers of A falla-
cis on leaves in these 6
orchards with those on
leaves in 6 similarly
treated and similarly
sampled first- and sec-
ond-stage IPM blocks
in 6 other orchards
where A fallacis were
not released.
Results
In the 2 orchards
where predators were
released in 1988 but
not in 1989, no native
A fallacis were seen in
June before A fallacis were released. After release, the
average ratio of pest mite to A fallacis frequency on
leaves in 1988 was 5 to 1 both in second-stage and first-
stage blocks (Table 1). A ratio of 5 to 1 is generally
considered to indicate a high probability of effective
biological mite control, while a ratio of 10 to 1 is
indicative of only moderate probability of such control.
In no block in any orchard in either year were predators
other than A fallacis (such as yellow mites) sufficiently
abundant to have affected the ratio of pest mites to A
fallacis. In 1989, there were extremely few pest mites
in either type of block in these 2 orchards until Septem-
ber, well after danger of damage by mites had passed.
Interestingly, there were extremely few or no A
Table 1.
Results in 2 orchards where A fallacis predators were released in July
of 1988 but not in 1989.
Percent of sampled
leaves with*
Tt j.' £ j.
Ratio of pest
Time of
ERM or
mites to
Year
sampling
Block type
TSM
AF
A fallacis
1988
June
Second-stage
15
0.0
15:0
First-stage
11
0.0
11:0
July
Second-stage
40
3.3
12:1
First-stage
38
2.6
15:1
August
Second-stage
21
9.5
2:1
First-stage
20
5.2
4:1
September
Second-stage
3
1.4
2:1
First-stage
7
4.8
2:1
Avg. for
July, Aug.,
Second-stage
21
4.7
5:1
and Sept.
First-stage
22
4.2
5:1
1989
June
Second-stage
0.0
0:0
First-stage
0.0
0:0
July
Second-stage
1
0.0
1:0
First-stage
0.0
0:0
August
Second-stage
1
0.0
1:0
First-stage
4
1.5
3:1
September
Second-stage
38
0.0
38:0
First-stage
10
0.0
10:0
Avg. for
July, Aug.,
Second-stage
13
0.0
13:0
and Sept.
First-stage
5
0.5
10:1
*On each sampling date,
in 1988 we sampled 10 leaves
per tree on 14 trees per
block (7 under which A fallacis were released and 7 adjacent trees) and in 1989
10 leaves per tree on 10 trees per block. ERM
= European red mites; TSM = two-
spotted mites; AF = A fallacis.
Fruit Notes, Winter, 1990
13
Table 2.:
Results in 4 orchards where A fallacis predators were released
in July of 1988
and agai
l in July of 1989.
Percent of sampled
leaves with*
Ratio of pest
Time of
ERM or
mites to
Year
sampling
Block type
TSM
AF
A fallacis
1988
June
Second-stage
42
0.0
42:0
First-stage
15
0.0
15:0
July
Second-stage
31
5.3
6:1
First-stage
33
5.1
6:1
August
Second-stage
17
1.8
9:1
First-stage
20
2.4
8:1
September
Second-stage
9
0.5
18:1
First-stage
12
0.0
12:0
Avg. for
July, Aug.,
Second-stage
19
2.5
8:1
and Sept.
First-stage
22
2.5
9:1
1989
June
Second-stage
32
0.0
32:0
First-stage
29
0.0
29:0
July
Second-stage
69
4.8
14:1
First-stage
55
3.0
18:1
August
Second-stage
51
15.3
3:1
First-stage
32
11.4
3:1
September
Second-stage
25
13.6
2:1
First-stage
8
11.5
1:1
Avg. for
July, Aug.,
Second-stage
48
11.2
4:1
and Sept.
First-stage
32
8.6
4:1
*0n each sampling date, we
sampled 10 leaves
per tree on 14 trees per
block (7 under
which A
fallacis were released and 7 adjacent trees) in
both 1988 and 1989. See
footnote
in Table 1 for explanation of ERM, TSM, AF.
fallacis predators found in these orchards in 1989. The
near total absence of pest mites in June, July, and
August may have stimulated the A fallacis to leave the
blocks and search elsewhere for prey. A fallacis do not
remain long on foliage harboring few potential prey.
The results in these 2 orchards suggest that A fallacis
eventually provided good suppression of pest mites in
both the second-stage and the first-stage control blocks
in 1988 and that a high level of suppression occurred
through August of 1989. The near absence of A fallacis
in our samples of September, 1989 in these 2 orchards
makes us wonder, however, if enough A fallacis will be
on hand in 1990 to provide effective suppression of pest
mites.
In the 4 orchards where predators were released in
both 1988 and
1989, again no
native A fallacis
were found in
June 1988, before
A fallacis were
released. After
release, the aver-
age ratio of pest
mite to A fallacis
frequency on
leaves in 1988 was
8 to 1 in the sec-
ond-stage blocks
versus9tolinthe
first-stage blocks
(Table 2). This
result suggests
that a moderate
level of biological
control was
reached. By late
June of 1989,
however, pest
mites had reached
average frequen-
cies of 32 and 29%
of leaves infested
in the second-
stage and first-
stage blocks, re-
spectively (Table
2). These fre-
quencies are only
slightly less than
the tolerable level
of pest mite popu-
lations on apple
trees in late June.
No A fallacis were found in any of the blocks in these
4 orchards in June. Conceivably, in these orchards,
early-season use in 1989 of pesticides to which the
released predators were not tolerant may have contrib-
uted to their lack of appearance in detectable numbers.
After release of veiy large numbers of A fallacis in July
of 1989 in these orchards, the average ratio of pest mite
to A fallacis frequency on leaves was 4 to 1 in both the
second-stage and first-stage blocks. These ratios sug-
gest that a high level of biological pest mite control
occurred in these 4 orchards. It will be most interesting
to see whether the high numbers of A fallacis present
in these 4 orchards in September of 1989 carry over to
provide effective biocontrol of pest mites in 1990.
It would be wrong to conclude from the foregoing
14
Fruit Notes, Winter, 1990
results that the observed
patterns of pest mite and
A fallacis abundance
were entirely the prod-
uct of A fallacis that we
had released. These pat-
terns may have been af-
fected in a substantial
way by natural popula-
tions of resident or
immigrating A fallacis.
Results from the second-
stage and first-stage IPM
blocks in the 6 orchards
where predators were
not released (Table 3)
suggest that resident or
immigrant A fallacis in
these blocks provided
little pest mite suppres-
sion in 1988 (average
ratios of pest mite to A
fallacis frequencies after
June were 38:1 and 18:1,
respectively) but pro-
vided good suppression
in 1989 (average ratios of
pest mite to A fallacis
frequencies after June
were 5:1 and 6:1, respec-
tively). Thus, the 1988
ratios in these blocks
where predators were
not released were con-
siderably less favorable
for biological control
than the 1988 ratios in
blocks where A fallacis
were released (Tables 1
and 2). On the other hand, in 1989 there was little dif-
ference in prey to predator ratio between blocks where
predators were or were not released in 1989.
Table 4 provides information on possible move-
mentof A fallacis from trees under orupon which they
were released, to trees immediately adjacent where
predators had not been released. For this purpose, we
combined data across both block types and across all
orchards where releases occurred that year. The
combined data for 1988 and 1989 indicate that about
2.2 times more A fallacis were present on the release
trees than on adjacent non-release trees in July, 1.4
times more in August, and 1.3 times more in Septem-
ber. This suggests that released A fallacis may have
moved in substantial numbers to neighboring trees a
Table 3.
Results in 6 orchards where no A fallacis predators were
released in
1988 or
1989.
Percent of
sampled
leaves with*
p
atio of pest
x\
Time of
ERMor
mites to
Year
sampling
Block type
TSM
AF A fallacis
1988
June
Second-stage
6
6:0
First-stage
1
1:0
July
Second-stage
10
0.2
50:1
First-stage
6
6:0
August
Second-stage
20
0.7
29:1
First-stage
13
0.5
26:1
September
Second-stage
12
0.2
60:1
First-stage
21
1.7
12:1
Avg. for
July, Aug.,
Second-stage
11
0.4
38:1
and Sept.
First-stage
13
0.7
18:1
1989
June
Second-stage
25
0.0
25:0
First-stage
27
0.0
27:0
July
Second-stage
25
2.5
10:1
First-stage
21
3.3
6:1
August
Second-stage
18
5.2
3:1
First-stage
16
2.5
6:1
September
Second-stage
28
6.8
4:1
First-stage
28
4.3
7:1
Avg. for
July, Aug.,
Second-stage
24
4.8
5:1
and Sept.
First-stage
22
3.4
6:1
*One each of the 3 sampling dates each year, we sampled ]
L0 leaves
per tree on
10 trees
per block. See footnote in Table 1 for
explanation
ofERM
, TSM, AF.
month or so after release. However, this suggestion is
based on the questionable assumption that the major-
ity of A fallacis observed were ones that had been
released (or their progeny) and were not of wild origin.
Conclusions
Can any firm conclusions be drawn from our find-
ings to date? Unfortunately, the answer is no. There is
simply no way to be certain that all or even some of the
A fallacis we observed on sampled apple leaves origi-
nated from releases of A fallacis and were not of wild
origin. Our conclusions, therefore, are highly tentative
and are based on the assumption that the majority of A
fallacis were in fact of released origin.
Fruit Notes, Winter, 1990
15
Table 4
. Presence of released A fallacis on trees under or upon
which they were
released
versus i
adjacent trees where none had been released.
Percent of sampled leaves
per orchard with
Predators
A fallacis
Number
of
Number
of trees
released
under these
Time of
ERMor
Year
sampling
orchards
per orchard
trees
TSM
AF
1988
July
6
14
YES
32
5.5
6
14
NO
35
3.1
August
6
14
YES
19
4.5
6
14
NO
18
3.1
September
6
14
YES
7
1.4
6
14
NO
9
1.1
1989
July
4
14
YES
63
5.9
4
14
NO
61
2.0
August
4
14
YES
38
15.7
4
14
NO
45
11.1
September
4
14
YES
16
15.1
4
14
NO
18
11.3
It appeared that there were few if any detectable
differences in the outcome of releases of A fallacis in
second-stage versus first-stage IPM blocks. It appears
that the released A fallacis, selected before release to
be resistant to organophosphate insecticides, may have
been able to withstand such pesticide treatments after
early June in the grower control blocks. We must
caution, however, that such resistance could eventu-
ally break down through introgression of genes from
wild-population A fallacis in cases where such popula-
tions are still susceptible to organophosphates.
It was clear that releasing about 500 A fallacis
adults on every fourth tree in a block (as was done in
1988 in all blocks) does not guarantee effective biologi-
cal control of pest mites either that year or the following
year. In 2 orchards, effective biological control did
occur (Table 1). In 4 orchards, moderate to relatively
little biological control occurred (Table 2). The pros-
pect for effective biocontrol within the same year of
release improved considerably when about 1500 A
fallacis adults per every fourth tree were released, as
was done in 1989. Still, we must wait to see if this very
high level of release will result in year-long suppression
of pest mites in 1990 and thereafter.
Finally, we must be patient. The full story of just
how effective are releases of A fallacis in apple or-
chards, compared with the alternative option of allow-
ing native A fallacis to build in the complete absence of
insecticide or miticide use after early June, may not be
known for at least a couple of more years, after contin-
ued future sampling in the 6 experimental orchards
where releases have been made and in the 6 compa-
rable orchards where no releases have been (or will be)
made. Researchers in the Netherlands believe that it
takes at least 4 years to see the full benefits of releasing
Typhlodromus pyri mite predators in Dutch orchards.
For now, we reserve full judgement and can only wait
to see what unfolds in 1990 and 1991.
Acknowledgments
We thank the Massachusetts Society for the Pro-
motion of Agriculture and federal/state agencies
granting apple IPM funds for supporting our work on
this project. Special thanks to Katharine Rankin and
Cheryl Donovan for their assistance, and Roy Van
Driesche for his helpful advice.
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16
Fruit Notes, Winter, 1990
Development of a Program for Grower and
Consultant Education and Certification
in Integrated Pest Management
William M. Coli and Craig S. Hollingsworth
Integrated Pest Management Program, University of Massachusetts
Recent consumer concerns over pesticides and food
safety have been reported conspicuously in local and
national media. Consumers are increasinglywary of the
food supply; they seek assurance that their food is safe.
Massachusetts growers have experienced reduced sales
from this media attention, and growers need a mecha-
nism to demonstrate to consumers that their produce is
safe.
One approach to this problem that some consumers
have taken, is to buy organically produced food. How-
ever, considerations of produce availability, quality, and
price, as well as technology and production costs, limit
the production of organic produce in the Common-
wealth. Another attempt to allay consumers' concern
over food safety has been the use of a "low spray" or
"IPM" label on produce. Such labelling has been lim-
ited, as no generally accepted standards for these catego-
ries exist.
Because adoption of IPM by commercial growers in
Massachusetts has been high, many growers have
mentioned their interest in being recognized for their
practices. Further, sponsors of pending pesticide reform
legislation are considering language that would give a
waiver of pollution liability for growers who use IPM.
In response to these developments, we submitted a
proposal to Massachusetts Department of Food and
Agriculture to develop a program of IPM education and
performance certification using resources at the Univer-
sity. Since as this proposal has received first-year fund-
ing, we believe it would be useful to inform growers,
consultants, and others of our plans at this time.
Objectives
The objectives of this project are threefold: 1) To
develop a state-wide program for the education of grow-
ers and agricultural consultants in the principles of
integrated pest management; 2) To develop guidelines
and standards to certify crops which are grown using
IPM principles; and, 3) to design and facilitate implem-
entation of a program of IPM performance certification.
Expected Results from This Project
Through educational materials and programs, it
is expected that this program will result in increased
knowledge of IPM by Massachusetts growers, and
that knowledge will result in greater adoption of IPM
techniques throughout the Commonwealth.
Through increased training and awareness, and
greater availability, more IPM-trained professional
consultants and scouts will be hired by the private
sector, further increasing the adoption on IPM and
creating jobs.
Increased use of IPM will result in reduced pesti-
cide use in the Commonwealth. Growers using IPM
certification on their produce will reap a marketing
advantage, when consumers, educated to IPM la-
belling, purchase produce that they know has been
grown using practices minimizing environmental dis-
ruption, and with minimal and safe pesticide use.
Educational Program
A project specialist will work with other Univer-
sity of Massachusetts research and Cooperative Ex-
tension staff to develop the curriculum and course
materials for an IPM short course. The short course
will be designed to teach growers, consultants, and
field personnel the basic principles and practices of an
integrated pest and crop management strategy.
Likely topics to be covered by the short course would
include: ecology of the agroecosystem; economic
thresholds; weather and disease monitoring; pest
sampling methodology; practical biological control;
cultural controls; and record keeping systems. Also
included would be topics on pesticide technology,
including: toxicology; effects of pesticides on non-
target organisms; movement of pesticides in the envi-
ronment; pesticide selection; biorational pesticides;
and sprayer calibration.
IPM short courses will be presented at Waltham
and Amherst. A test on the material will be given.
Individuals passing the test will receive a certificate of
Fruit Notes, Winter, 1990
17
successful completion by the University of Massachu-
setts Cooperative Extension.
Certification of Consultants
Many growers, especially those with long-estab-
lished and effective IPM programs, possess enough
knowledge to implement an IPM program. What most
lack, however, is the time to monitor their fields ade-
quately. Hence, one of the greatest limitations to
successful, large-scale IPM implementation is a lack of
trained individuals to monitor fields and make recom-
mendations.
There are currently six scout/consultants in the
state who offer IPM services for no more than 5000
acres of crops, largely apples and cranberries. Should
greater numbers of consultants become available,
growers who hire them at a rate sufficient to represent
a living wage, have a right to expect such consultants to
be well-trained and qualified, and able to be trusted
with a valuable crop. Certification of IPM consultants
would help growers make hiring decisions.
IPM Certification Standards
Produce to be marketed or labelled as "IPM-
Grown," should be grown using certain specified prac-
tices or standards. This project proposes to develop
IPM guidelines for specific crops where feasible.
Where IPM technology is insufficient to develop appro-
priate guidelines, this project will outline what infor-
mation is needed to develop IPM standards.
In order for consumers to be confident that "IPM-
Grown" labeled commodities are true-to-name, some
form of performance certification will be necessary.
While this could take the form of a state regulatory
agency making spot inspections of production practices
to insure that they conform to specified IPM standards,
other options exist, including certification by the mar-
keting division of state government, by some private
entity, or by an organized grower group. The issue of
assigning responsibility for certification inspections
will be difficult to resolve.
Time Table
This program will begin in the fall of 1989 and is
anticipated to run for 2 years. The IPM Certification
Specialist will work closely with the State IPM Coor-
dinator, other University faculty and staff, as well as
consultants and growers to carry out the project,
using the latest research-based information available
here and in other states.
Curricula for the first short courses will be devel-
oped during the Winter of 1989-90. Production of a
curriculum manual to accompany the short course will
be initiated as well. Two short courses will be pre-
sented and participants will be certified upon success-
ful completion in the Spring of 1990.
Also in the first year, compilation of a list of com-
modities grown in Massachusetts, and the data needed
for their IPM certification will be initiated. A protocol
for developing IPM certification guidelines will be
developed and guidelines for IPM production of apples,
potatoes, strawberries, and sweet corn will be com-
pleted. Avenues of performance certification, including
its legal ramifications, as well as the practicality of
using state, federal, or other agencies for certification of
performance, will be explored.
During the second year of the program, the educa-
tional component will continue as demand warrants;
two short courses will be held in the Winter. The short
course manual will be completed. Guidelines for IPM
certification of cole crops, cranberries, greenhouse
production, and turf will be completed, and guidelines
for nursery crops will be begun. Procedures for certifi-
cation of IPM performance will be developed, and the
eventual certifying agency will be assisted in imple-
menting the certification program.
If you would like more information about our plan,
please contact either author at 413-545-2283.
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18
Fruit Notes, Winter, 1990
Effects of the Loss of EBDC Fungicides on
Apple IPM in New England
Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Stephen Wood
New England Fruit Growers' Council on the Environment
John Schneider
Very fine Products, Inc., Technical Department
Over the past several years, fungicides have been
the subject of steadily increasing criticism from food
safety advocates. At the moment, they are also in the
center of EPA's limelight.
Many of the fungicides New England growers rely
on to control diseases in fruit crops are thought to have
the potential to cause various chronic, human-health
disorders. As a result, growers have cause to wonder
about the future of the fungicides they now use. Some
may soon be regulated off the market, some may be
dropped from the market by their manufacturers, and
some may be driven from the market by another explo-
sion of public emotion.
Right now, the fungicides at center stage are the
ethylene bisdithiocarbamates (EBDCs) which include
all formulations of maneb (Maneb™, Dithane M-22™,
Manzate D™, Manex™, etc.), mancozeb (Dithane M-
45™, Manzate 200™, Penncozeb™, Dikar™, etc.),
metiram (Polyram™, Zinc-metiram™, etc.) and zineb.
Anticipating a recommendation from EPA that future
use on apples be forbidden, the registrants of all EBDC
fungicides agreed to drop apples from the 1990 label.
This measure presents growers with the problem of
producing next year's crop, and possibly every crop
thereafter, without EBDC fungicides.
This paper attempts to describe the effects of the
loss of EBDC fungicides on IPM fruit growers in New
England, and more generally to explain the extent to
which successful IPM depends on the continued availa-
bility of a broad variety of similar fungicides.
Most older fungicides (registered before 1970) are
under fire for their potential to cause cancer, tumors,
reproductive disorders, or a variety of other chronic
health problems. Under the present regulatory
scheme, the EPA attempts to determine which com-
pounds with similar uses present the lowest theoretical
risk. In a given group of materials with similar uses,
the compound with the lowest risk is cleared for contin-
ued use, while the "more hazardous alternatives" are
disallowed. Certain proposed legislation is intended to
compel EPA to take this approach.
The problem with this approach, from an IPM
grower's perspective, is that it will hamper the ability
to be precise. There is no "all purpose fungicide."
While it is useful conceptually to think of benzim-
idizoles or EBDCs as apple scab fungicides, each com-
pound has specific properties which make it the most
appropriate material to use under a given set of cir-
cumstances. IPM growers make pesticide use deci-
sions that are highly specific to the exact combinations
of diseases, arthropods, stages of tree development,
and environmental conditions present in their or-
chards at given times. Growers also specifically apply
fungicides to different pails of the orchard, depending
on cultivar or tree size. Without a wide variety of
chemicals from which to choose, such precision would
be impossible. In fact, a reduction in the number of
available fungicides will limit precision rather than
lowering the volume of fungicide used. The hard fact is
that two compounds that control the same disease
virtually never have the same full range of effects.
Without EBDCs next year, New England IPM
growers will experience a painful example of this limi-
tation. Assuming for now that no EBDCs will be
available for use on apples in 1990, our toolbox for next
year will contain the following fungicides.
Bcnomyl (Benlate™)
Captan (Captcc™, Orthocide™)
Dodine (Cyprex™)
Fenarimol (Rubigan™)
Ferbam
Fixed coppers (Kocide™, COCS™)
Myclobutanil (Nova™)
Sulfur
Thiophanate-methyl (Topsin-M™)
Thiram
Triforine (Funginex™)
Fruit Notes, Winter, 1990
19
To a person unfamiliar with the ecology of a New
England apple orchard, this list may seem like more
than enough options. However, to an IPM grower, the
withdrawal of the EBDCs is frightening. The reasons
emerge from a closer examination of the remaining
materials.
Benomyl and thiophanate-methyl can interfere
with biological mite control by suppressing popula-
tions of Amblyseius fallacis, our most important mite
predator. Biocontrol of mites in apple trees is essential
to second-stage or biointensive IPM. Additionally, in-
tensive use of benzimidazoles may lead to earthworm
suppression.
Benzimidazoles are recommended for use only in
specific situations, such as to inhibit scab sporulation.
Exclusive use of benzimidazoles can lead to resistant
strains of Venturia inaequalis, the apple scab fungus.
Resistance already precludes use of these compounds
in some states. To extend the useful life of these
materials, and to avoid stressing mite predators, they
must be used sparingly and always in combination
with another broad-spectrum fungicide such as captan
or the EBDCs.
Captan has recently been re-registered by EPA,
but is still the target of strenuous criticism by food
safety advocates. While a very useful fungicide against
scab and black rot, it does not control mildew, and is
only marginally effective on sooty blotch and fly speck.
Specifically, in a year such as 1989, 4 captan applica-
tions would have been made for sooty blotch and fly
speck, compared to 1 or 2 applications of an appropriate
EBDC.
The gravest difficulty with an attempt to use cap-
tan as a complete alternative to EBDCs arises from
captan's incompatibility with oil or alkaline materials.
The EBDCs do not share this unfortunate characteris-
tic. When combined with oil, or even when used within
14 days of an oil application, captan can be toxic to plant
tissue (phytotoxic). Biological mite control depends on
1 or 2 oil applications in the middle of primary scab
season. Without the EBDCs, growers are faced with 3
options:
1. Damage to the tree by captan/oil combina-
tion.
2. Oil combined with no fungicide or an infe-
rior scab fungicide, resulting in primary sea-
son infections and a season-long fungicidal
battle against serious crop damage.
3. No oil before bloom resulting in an expen-
sive chemical program against phytophagous
mites, without benefit of predator mites.
No grower will choose the first option, and the other
two violate every principle of IPM and will increase
drastically the total volume of pesticide used in New
England apple production.
Dodine may not be manufactured next season. In
any case, though a potent scab eradicant, it can and has
produced resistant scab strains. Over-reliance on
dodine will shorten its useful life, and already has done
so for many growers. Dodine is not effective against
apple diseases other than scab, and would generally
have to be used in conjunction with other fungicides.
Ferbam is at best moderately effective against
scab and has no post-infection activity, so it must be
used as a protectant. While it is fairly effective against
rust and summer diseases, ferbam leaves a heavy,
black, visible residue for some time, which tends to
discourage consumers.
Fixed coppers are useful in their place, which is a
single early-season application. Used after this time,
copper will damage leaves and russet fruit.
Fenarimol, myclobutanil, and triforine . or ergos-
terol biosynthesis inhibitors (EBIs), are a relatively
new class of fungicides. Though highly effective against
scab and (except Funginex) mildew, they do not con-
trol other diseases and are expensive. Moreover, they
are poor protectants, and their extremely specific mode
of action suggest the possibility that they may induce
pathogen resistance. Reports from Europe reinforce
this suggestion. To prevent this development, and to
provide for protectant activity, New England patholo-
gists have recommended that EBIs be used with a
broad-spectrum fungicide. EBDCs have been the fun-
gicide of choice, because they are compatible with oil.
Captan is the second choice, but will present the oil
phytotoxicity problems discussed earlier. Without the
EBDCs, the EBIs may be of marginal utility in New
England.
Thiram has about the same range of activity as
captan but is considerably less effective. Many growers
consider that its chief value is as a deer repellent.
Sulfur, while a favorite of organic growers, is
barely effective against scab, is toxic to mite predators,
and can be phytotoxic. To control scab, growers would
normally apply much more sulfur than they would any
other fungicide. This application leads to concerns
about soil acidification.
If EBDCs were available, they would be described
as follows:
EBDCs are highly effective against scab and
summer diseases, but are useless against powdery
mildew. Use at full rates late in the growing season can
result in visible residues at harvest. Like captan,
EBDCs have virtually no potential to produce patho-
gen resistance. The compatibility of EBDCs with oil
makes them the mainstay of most New England IPM
disease-management programs. Their use incombina-
20
Fruit Notes, Winter, 1990
tion with EBIs allows at least 10-day intervals between
fungicide applications, which is at least 3 days longer
than with any other fungicide. This program substan-
tially reduces the overall fungicide load in an orchard.
It should be obvious why IPM growers, consult-
ants, and researchers are distressed at the loss, at least
temporarily of EBDCs. Without the EBDCs, we can
confidently predict that overall fungicide use will in-
crease in New England in 1990. Miticide use will also
increase. The irony of the situation appears even more
acute when we consider that the most important IPM
use of EBDCs occurs before bloom, before fruit forma-
tion, and therefore before any possibility of residue
being deposited on the harvested crop. A related article
in this issue indicates that EBDC residue is probably
not a problem when applications are made early in the
season.
For these reasons, regaining some apple uses for
the EBDCs is most desirable. The EBDC fungicides
provide several specific and important management
options in apple IPM. Specifically, they can be used
with oil, allowing mite biocontrol. They also allow the
EBIs to be used in so-called "extended interval" pro-
grams, which reduce the amount of fungicide per sea-
son. They allow extended intervals during the sum-
mer. In reality, the only effective, broad-spectrum
fungicide left for apples is captan, in spite of its limi-
tations.
We hope that two points have emerged from this
work:
1. Present regulatory efforts to reduce risks from
fungicides aim at the identification and elimination of
"bad actors," or the individual compounds that appear
likeliest to endanger human health. This narrow
approach will frustrate real-world efforts to reduce
fungicide use, because it limits growers' ability to ex-
ploit the subtle but important differences between
similar compounds. When the benefits of a compound
are considered, its value in reducing the use of other
compounds and the overall ecological effect of such re-
ductions should be part of the consideration. Con-
versely, how the removal of compounds may increase
the overall use of similar fungicides, or even other
pesticides, should be considered. Regulators must look
more closely at how the use of each compound relates
to the use of all pesticides. The effect of the loss of the
EBDCs on New England apple IPM sharpens these
points painfully.
2. Growers and researchers must put themselves in a
better position to inform regulators about the various
compounds that come under regulatory scrutiny. The
apple industry must perform a use-pattern survey
similar to the preliminary study also presented in this
issue, but covering the complete range of compounds
and apple ecosystems. Such a study, combined with
data on residue, disease damage, and arthropod dam-
age, would greatly expand our own knowledge of our
chemical use, while enabling us to provide EPA with
the sort of information the agency needs to regulate
wisely.
We growers and agricultural researchers can, by
studying our own work, contribute sound information
to the regulatory process. If we do, we are likely to be
able to retain the use of some valuable tools. We might
yet defend our use of EBDCs successfully, if we are
quick and willing to accept or even propose stricter
limitations on their use. We must stop reacting after
the rules are written and start helping to write the
rules.
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Fruit Notes, Winter, 1990
21
Factors Affecting EBDC Fungicide
Residues in Apple Fruit
Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Stephen Wood
New England Fruit Growers' Council on the Environment
John Schneider
Very fine Products, Inc., Technical Department
Apple growers, researchers, and food processors
are deeply concerned with the prohlems presented hy
the loss of EBDC fungicides. In general, these concerns
may he summarized by saying that the loss of the
EBDCs as an option will compel growers to use more
pesticides in their apple pest management programs
(see "Effects of the Loss of EBDC Fungicides on Apple
IPM in New England" in this issue). Here we examine
the results of a use pattern/residue survey done in
1988 in cooperation with a number of New England
apple growers.
The survey was intended as a preliminary study of
how use of the EBDCs and captan (and at that time,
daminozide) might affect residues in apple fruit. Sev-
eral growers throughout New England were contacted
by the New England Fruit Growers Council on the En-
vironment and asked to sample blocks and send infor-
mation about those blocks to us. The growers were
instructed to sample randomly throughout a given
block. Samples were obtained from 28 blocks. The
unwashed, raw samples were sent to the Veryfine
Technical Laboratory, where they were assigned an ID
number. Each block sample was split into two groups,
bagged in plastic, and boxed. Half of each sample was
then sent to the National Food Processors Laboratoiy
in Washington, D.C. for captan/EBDC residue analy-
Number of
Applications
12
1
8
No residue detected
Residue detected
I I I I
nil i inn i i I ii |i ri 1 1 1 ti
in i nim i i in lines si
9 1113
Orchard Block
15 17 19 21 23 25 27
Figure 1. The number of EBDC applications made for the 1988 season, compared with the EBDC residue
on apple samples. Where detectable, the amount of residue increases from left to right; blocks which had
no detected residues are represented in the white background, and blocks with a detected residue are in
the shaded background.
22
Fruit Notes, Winter, 1990
ses. (The other half was retained at Veryfine for
daminozide residue analysis as part of the overall
study.)
Amounts and dates of pesticide application were
obtained from growers, as well as information on vari-
ous tree and block characteristics. Data analysis was
done at the University of Massachusetts. The key
factors we examined were the number of applications,
the interval between the last application and harvest,
the amount of EBDC formulation applied per acre over
the season, the number of applications made and the
amount of fungicide applied after the last significant
rain of the season in July, and the amount of captan ap-
plied relative to the amount of EBDCs.
Of the 28 blocks tested, 10 had EBDC residues
which were detected. Of these, 1 had received 4 appli-
cations of an EBDC, 1 had received 6 applications, and
the rest had received 7 or more. Of the blocks with non-
detected residues, all had received 8 or less EBDC
applications over the season (Figure 1). Thus, we esti-
mated a "break-point," or point where residues built
up sufficiently to be detected in 9 of 10 cases, at 6
applications. The EBDC residues and the numbers of
applications for the season were well related ( r = 0.69;
the correlation coefficient, r, is a statistic which ranges
between -land + l.indicatingthe degree of correlation,
with meaning no correlation and + 1 or -1 meaning
perfect correlation).
We next examined the effect that the total amount
of EBDC fungicides applied over the season had on the
measured residue (Figure 2). Of course, the total
amount of fungicide applied over a season increased as
the number of applications per season increased (r =
0.95). As would be expected, the more fungicide ap-
plied, the more residue detected (r = 0.66). The
apparent "break point" was at about 15 pounds/acre/
season.
One might also expect that the number of days
between the last EBDC application and harvest would
affect residues. While there was a moderate correla-
tion, the relationship was not as strong (r = -0.33) as
that observed with some of the other factors (Figure 3).
We also considered that significant rain which
occurred in July may have removed residue approxi-
mately 60 to 70 days before harvest. During the 10 days
prior to July 23, over 8 inches of rain fell in many areas.
Therefore we examined the number of applications
and the pounds of EBDC applied after the July 23 rain.
Of the 13 blocks which received applications of EBDC
after July 23, 8 blocks had detected residue, and 5 did
not (Figure 4). All blocks that received 2 applications
after July 23 had detected residues, indicating that late
applications were related to residue (r = 0.64). The
pounds per acre applied after July 23 were more closely
related (r = 0.78), and more fungicide was applied after
July 23 in 8 of the 10 blocks with detected residues than
in the blocks with no detected residues (Figure 5).
We also examined the amounts of captan relative
Lbs./Acre Applied
Over the Season
60
50
40
30
20
1
No residue detected
."■ Residue detGcted;H: :
:.:.•. .■*.-, ^^_ w-:a- : •>^-»- ::■•;:■;■ y.'.'s'-y-
^m " '.:'::■"•" ^M : ' ^1
^ ■ -.-■■.-.-..-. ...-.v-;.v. : .> ^^ .-..■. .v.:. :./..:•:■■-> ^H ■•--■•:-:• ^B
I ■::■';:■' ^H -^^ ^^ ^B •*•*•_• j ^H
III! ill lli
9 11 13 15
Orchard Block
17 19 21 23 25 27
Figure 2. The pounds of EBDC fungicide used per acre for the 1988 season, compared with the EBDC
residue on apple samples. Where detectable, the amount of residue increases from left to right; blocks
which had no detected residues are represented in the white background, and blocks with a detected
residue are in the shaded background.
Fruit Notes, Winter, 1990
23
Days from Last EBDC
Application to Harvest
100
n mm
ii 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ? 1 i i 1 1 1 1 n
1 3 5 7 9 1 1 13 15 17 1 9 21 23 25 27
Orchard Block
Figure 3. The number of days between the last EBDC application and harvest, compared with the EBDC
residue on apple samples. Where detectable, the amount of residue increases from left to right; blocks
which had no detected residues are represented in the white background, and blocks with a detected
residue are in the shaded background.
Applications
After July 23
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
1
No residue detected
-*— i — i — i — i — i — i— i — t — t- t t t
7 9 1 1 13 1 5 1 7 1 9 21 23 25 27
Orchard Block
Figure 4. The number of applications of EBDC fungicide made after the last major rain of the season (July
23), compared with the EBDC residue on apple samples. Where detectable, the amount of residue
increases from left to right; blocks which had no detected residues are represented in the white background,
and blocks with a detected residue are in the shaded background.
24
Fruit Notes, Winter, 1990
Lbs./Acre
After 7/23
6
5
4
3
2
1
■■■■i n r
sidue detected
"•~-yyv j y. j **',''. '.'•'* 's/ys. «*•> :«•>?■:
No residue detected
•'.'". flW '
'■:'-...■'■.: : ■■Vii:]:fif-::K : :-}y\:f: : ■ ■ I ■
i ™™™aim» ||m| | |
fl ■ 1 : m ■ ■
!!!
■
1 1 1
1 II
|i P
1 1 1
: II
;:!.;;:■! II
1 — t t
— i — i— — i — •— i — i — • — i — ♦— ♦
II
1 1
1
15 17 19 21 23 25 27
3 5 7 9 1113
Orchard Block
Figure 5. The number of pounds of EBDC fungicide applied after the last major rain of the season (July
23), compared with the EBDC residue on apple samples. Where detectable, the amount of residue increases
from left to right; blocks which had no detected residues are represented in the white background, and
blocks with a detected residue are in the shaded background.
Number of
Applications
1 4
1 2
1
8
6
4
2
Captan
EBDC
No residue detected
•>x-" J <w>ic.)o.»»»x
X Residue detected i
:■::<>•.-:■.■
1
17 19 21 23 25 27
I llll I II II III 1 1
1 1 1 1 1 1 1 llll I II llljiilftl
llll III llll I II Mill llll
3 5 7 9 1113 15
Orchard Block
Figure 6. The number of captan and EBDC fungicide applications over the 1988 season, compared with
the EBDC residue on apple samples. Where detectable, the amount of residue increases from left to right;
blocks which had no detected residues are represented in the white background, and blocks with a
detected residue are in the shaded background.
Fruit Notes, Winter, 1990
25
Lbs./Acre
per Year
60
50
40
30
20
1
Captan
EBDC
No residue detected
^j
[
"Residue detected 1
i
FT
nrnrmiiiiiiiin sniniE i
9 11 13
Orchard Block
15 17 19 21 23 25 27
Figure 7. The pounds of captan and EBDC fungicide applied over the 1988 season compared, with the
EBDC residue on apple samples. Where detectable, the amount of residue increases from left to right;
blocks which had no detected residues are represented in the white background, and blocks with a
detected residue are in the shaded background.
EBDC
Residues
y = .036x -.121x + .07
10
Lbs. EBDC applied after July 23
Figure 8. EBDC residues as a function of the pounds of EBDCs
applied after July 23.
to EBDC fungicides used over the
season. In general, as the number
of EBDC applications decreased,
the number of captan applications
increased (r = -0.73) (Figure 6).
Interestingly, as the combined
number of applications for both
types of fungicide decreased, the
mix of captan and EBDC was the
most balanced. These same blocks
were also ones in which EBDC resi-
dues were not detected. (Only one
block, no. 3, had detected captan
residues.) The pounds per acre per
season of each material were less
closely related (r = -0.48), but
showed the same pattern (Figure
7). The correlation between the
pounds of captan per acre for the
season and EBDC residues was
low, but significant (r = 0.44). Not
surprisingly, the pattern suggests
that using more captan reduces the
use of EBDCs, and reduces the
EBDC residue.
If we could use some simple
standards, such as the number of
applications or the total pounds per
acre applied, to predict whether
EBDC residues would remain on
26
Fruit Notes, Winter, 1990
the fruit, it might be possible to label EBDCs for limited
use. Toward this end we attempted to determine
which of the factors we examined might best predict
EBDC residue in this survey. Using the number of
applications and the total pounds per acre applied for
the season, we could account for about 44% of the
change in EBDC residue . If we looked at the number
of EBDC applications after July 23 and the pounds of
EBDC applied after July 23, we could account for about
69% of the change in EBDC residue. By using a
different type of equation (quadratic) with the pounds
of EBDC applied after July 23, 84% of the change in
EBDC residues could be predicted. This was as well as
we were able to do with the data (Figure 8).
In conclusion, we see this as preliminary informa-
tion indicatingthat concern over EBDC residue may be
managed by changing application timing and amounts.
We certainly do not advocate using crop protectants
which pose a threat to public health and the environ-
ment, regardless of benefits to production. However,
we suggest that it is worthwhile to re-examine costs
and benefits in the context of actual use patterns,
particularly within IPM programs. If information like
that presented here were true for a national sample
over several years, it would indicate that limited use of
EBDC fungicides would not be a health threat. In fact,
as we have argued elsewhere, keeping specific uses for
EBDC fungicides would in fact be a net benefit for food
safety and environmental pollution, because they
would benefit apple IPM programs.
•!# «$# %1* %I# *%
#2* %"* *X* r i» *$*
Massachusetts Apple IPM Program:
Observations in 1989
Kathleen Leahy, Ronald J. Prokopy, and William M. Coli
Department of Entomology, University of Massachusetts
Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Our thanks to the following growers who partici-
pated in the IPM monitoring program this year: Alex
Dowse, Tony Lincoln, Tony Rossi, Don Schlicke and
Bill Rose, Steve Smedberg, Mike and Tim Smith, Mike
Smolak, and Denis Wagner.
IPM-Related Research
Spray trials done at the Horticulture Research
Center in Belchertown, and with cooperating commer-
cial growers, included tests of the insect growth regula-
tor Dimilin™, Safers Soap™, sterol inhibiting (SI)
fungicides, and delayed, reduced fungicide applica-
tions.
Two efforts were made to promote biological pest
control in orchards. First, we collected and released
200 adults, larvae, and pupae of the small black lady-
bird beetle Stethorus punctum, an important mite
predator in some parts of the Northeast, into two first-
stage IPM orchards. Second, we collaborated with Roy
van Driesche (University of Massachusetts Biocontrol
Coordinator) and Chris Maier (Connecticut Agricul-
tural Experiment Station) in culturing and releasing
several hundred adults of Testaceipes holcothorax,
which parasitizes leafminer eggs. We will monitor the
populations of these predators to determine their effec-
tiveness and their survival in our conditions.
The manufacturers of EBDC fungicides have
asked that the label for apples be suspended, in order to
allow them to develop data on dietary risk without the
hysteria which occurred regarding Alar™. As a result,
many of the most common apple fungicides now used
will not be available in 1990. We have taken two
approaches to this problem.
First, with a group of New England growers, we
developed a profile of EBDC and Captan use patterns,
and correlated these data with residues on fruit. See
the article in this issue on the results of this survey.
Second, in conjunction with David Rosenberger at
the Hudson Valley Laboratory and Wayne Wilcox at
Fruit Notes, Winter, 1990
27
the New York Agricultural Experiment Station at
Geneva, we have done tests toward the economic use of
the SI fungicides. This program was tested in 4 grower
blocks this year. In all 4 blocks, primary scab control
was superior to that in check blocks, with virtually no
scab present at the end of primary season in the test
blocks. The first applications were delayed, on average,
until the tight cluster stage of tree development, and
involved an average of 4 primary season sprays, com-
pared to an average of 5.5 applications in check blocks
where the SI fungicides were not used.
Diseases in 1989
With the very wet weather we had this year, dis-
ease problems were by and large more notable than
insect problems. Incidence of fruit injury is given in
Figure 1.
Fire blight . Of major concern to some growers in
Massachusetts was a severe outbreak of fire blight,
most often in orchards which previously had not had
problems with this disease. Most growers who previ-
ously experienced a fire blight problem had used a
dormant fixed copper spray, and did not have trouble
this year. The problem seemed to be primarily in the
central region of the state. The outbreak was all stem
blight, with no blossom blight. In the past, this problem
generally has occurred in conjunction with aphid or
leafhopper population development at the end of June.
This year, the first date of occurrence was mid- June to
mid-July. In two cases, large parts of entire orchards
were infected.
Scab . Scab was evident late in the season on
poorly-pruned trees, and pinpoint scab was noted on
some fruit at harvest. In most cases where a spray was
misapplied (timing or amount), there was disease
3
1.50--
1.00
0.50--
0.00
SCAB CALYX BLACK SOOTY OTHER
END- ROT ROT BLOTCH/
FLYSPECK
Figurel. Harvest injury in first-stage IPM blocks. Disease injury
in 1978-88 as compared to injury in 1989.
development. Primary pressure was high and lasted
about 5 to 7 days later than last year. In the majority of
orchards, however, scab control was satisfactory.
Flyspeck/sooty blotch . Not surprisingly, in view of
the very wet weather this year, flyspeck was a signifi-
cant problem in orchards which had not been ade-
quately covered with summer fungicides. Sooty blotch
was less prevalent but also present, particularly in
orchards that had used a very light summer fungicide
program. Since light summer programs were being
promoted, growers found themselves in a dilemma:
high disease pressure vs. potentially adverse public
opinion. This year had the worst overall summer
disease situation we have seen in over ten years.
Ron Prokopy observed approximately 5% flyspeck
and 60% sooty blotch on non-fungicide treated Liberty
on his farm.
Brooks spot . Possible Brooks spot was seen on the
cultivar Spencer in one block, although the field iden-
tification was not confirmed by isolation.
Summer rots . More summer rots were seen this
year than in most years, but the level was still not
economically important. Bitter rot and black rot were
the predominant rots, depending on the orchard.
Insects in 1989
Insects and mites were less of a problem in most
orchards this year than in other years, as can be seen
from the incidence of fruit injury in Figure 2.
Plant bug . Activity was very low again this spring.
As always, it was difficult to assess tarnished plant bug
damage at harvest because of similarities with other
insect damage, but on the whole it appears that virtu-
ally no downgrading occurred as a result of plant bug
damage.
Leafminer . Parasitism and other
causes of leafminer mortality were
unusually high this year (over 60% of
second-generation mines in some
monitored blocks). Due to the cool
weather, mine development was
slowed and should have caused less
tree stress. Leaf mines were observed
on pear trees in Belchertown. Al-
though signs of emergence were seen in
some mines (indicating that pear trees
are an acceptable host for this insect),
we were not successful in trapping
emerging moths to see if they were the
same species as the leafminers infest-
ing apples. The larvae were veiy simi-
lar, however.
ES 1978-88
E2S 1989
28
Fruit Notes, Winter, 1990
1.50
1.00
3
se °- 50
0.00
OTHER
Figure 2. Harvest injury in first-stage IPM blocks. Insect injury
in 1978-88 as compared to injury in 1989. TPB = tarnished plant
bug; EA = European apple sawfly; PC = plum curculio; LR =
leafrollers; AMF = apple maggot fly; GFW = green fruitworm;
CM = codling moth; SJS = San Jose scale.
Mites . Again this year, mite populations were
generally low, although there were some notable ex-
ceptions, and growers in the monitoring program used
an average of 1.25 dosage equivalents of miticide.
Predators continued to increase in many of the state's
orchards, including Amblyseius fallacis, Zetzellia mali,
Orius insidiosus, and also possibly Stethoruspunctum.
Predation was late building up this year.
Plum curculio . Curculio activity was unusually
prolonged (through early July in some orchards) but
the level of harvest injury in most first-stage blocks was
not unduly high, perhaps because growers were alert
and treated promptly. Some blocks, however, did have
unusually high levels of late-June curculio injury.
White apple leafhopper . This insect is increasingly
evident in Massachusetts orchards, and may be associ-
ated with the fire blight outbreak
mentioned above.
Green fruitworm . Damage that
appears to have been caused by green
fruitworm has been showing up in our
harvest surveys (0.6% in one 12-block
survey), although it does not seem to
be of concern to most growers, and
injury levels probably do not justify a
special application of insecticide.
Leafroller/slug . A fair amount of
surface feeding was noted at harvest in
some blocks, although much of this
feedingwas on dropped fruit. Some of
it was caused by leafroller, but slugs
also had a field day with the damp
weather, and have been seen on at-
tached fruit as well as drops.
Aphids . In most orchards, aphids
seemed to come and go very quickly
this year. Predators were abundant.
Some growers used Thiodan T M against the summer
flight of leafminers, which would have contributed to
the early demise of the aphids; also, the cool.wet
weather may not have allowed aphids to flourish at
their usual levels this year.
Tent caterpillars/gypsy moths . These caterpillars
were more common this year than they have been for
a while. Apparently another population outbreak is
predicted in the next few years. Neither insect pre-
sented much of a problem to growers except on non-
bearing young trees that were not under a full spray
program.
Thrips . Numbers of pear thrips were substantially
lower in commercial blocks than they have been in
recent years, although they still caused some reduction
in fruit set in low-spray, non-commercial orchards.
4.T.* *% C% «f« fcf>
«rj% cy» e|^ #{% r£»
Fruit Notes, Winter, 1990
29
Fruit Notes
University of Massachusetts
Department of Plant & Soil Sciences
205 Bowditch Hall
Amherst, MA 01003
Nonprofit Organization
U.S. Postage Paid
Permit No. 2
Amherst, MA 01 002
serial section
univ. library
FN
01003
Account No. 3-20685
l&rr, i\
5
r
Fruit Notes
^v
ISSN 0427-6906
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
j
Volume 55, Number 2
SPRING ISSUE, 1990
B!OLOG!CAL
MAY U 3 1990
SCIENCES LIBRARY
Table of Contents
Comparison of Ripening and Fruit Quality of Gala and
Mcintosh Apples at Harvest and Following Air Storage
Pomological Note: Blueberry Cultivar Update
Commercial Potential of Red Fuji in New England
Preliminary Observations of Redmax in Massachusetts
Managing Small Fruit Crops for the Retail Market
Food for Thought
Peach Cultivars
Effectiveness of Dimilin™ Against Apple Blotch Leafminere
Evaluation of Dimilin™ Against Pear Psylla
Advancements in Second-stage Apple IPM:
Substituting for "Sticky" on Baited Red Spheres
Evaluation of Safer's™ Insecticidal Soap as a
Management Tool in Apple Orchards
Insecticidal Soap for Pear Psylla Management
Fruit Notes
Publication Information:
Fruit Notes (ISSN 0427-6906) is published the first day of January,
April, July, and October by the Department of Plant & Soil Sciences,
University of Massachusetts.
The costs of subscriptions to Fruit Notes are $5.00 for United States
addresses and $6.00 for foreign addresses. Each one-year subscrip-
tion begins January 1 and ends December 31. Some back issues are
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dresses). Payments must be in United States currency and should be
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Correspondence should be sent to:
Fruit Notes
Department of Plant & Soil Sciences
205 Bowditch Hall
University of Massachusetts
Amherst, MA 01003
COOPERATIVE EXTENSION POLICY:
All chemical usessuggested 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 the University of Massachusetts Cooperative Extension, Robert G. Helgesen, Director, in furtherance of the acts
of May 8 and June 30, 1914. The University of Massachusetts Cooperative Extension offers equal opportunity in progwms
and employment
Comparison of Ripening and Fruit Quality of
Gala and Mcintosh Apples at Harvest and
Following Air Storage
Duane W. Greene and Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
Gala is becoming one of the most popular and
widely planted apple cultivars in the world. It is a very
high quality apple with broad consumer appeal. We
have been harvesting and evalu-
ating Gala/M.26 for several years
from trees planted at the Horti-
cultural Research Center in Bel-
chertown in 1978. Descriptions
and observations have appeared
in previous Fruit Notes articles
[49(2):18; 51(1):12-14]. Since
Gala appears to be such a promis-
ing apple, we initiated a study of
ripening, fruit quality, and stor-
age potential to determine if Gala
could be a reasonable alternative
to Mcintosh for growers in Massa-
chusetts who wish to reduce their
Mcintosh acreage.
Fruit used in this investiga-
tion were collected in 1988 from
Kidd's D-8 Gala/M.26 planted in
1978 and Rogers Mclntosh/M.26
planted in 1976 at the University
of Massachusetts Horticultural
Research Center in Belchertown,
MA. The Mcintosh trees received
750 ppm of daminozide on July
18, 1988.
Fruit Quality and Ripening
Ten fruit per tree were col-
lected randomly from 3 Gala and 3
Mcintosh trees at weekly inter-
vals starting on August 24 and
continuing through October 19.
Fruit collection was made from
the interior and exterior portions
of all quadrants of each tree. On
each date fruit were evaluated for
percent and intensity of red color,
flesh firmness, soluble solids, titratable acidity, fruit
weight, and internal ethylene.
When the initial harvest was made on August 24,
Table 1. Effects of time of harvest and lengths of storage period on fruit
quality of Gala and Mcintosh apples.
Flesh Soluble
firmness solids
Treatment (lbs) (%)
Titratable
acidity
(meq/100 ml)
Harvest date (mean of both cultivars)
Sept. 15 13.5 10.8
Sept. 22 12.6 11.0
Sept. 29 12.5 11.6
6.4
6.3
6.5
Significance ** **
NS
Evaluation date (mean of both cultivars)
Harvest 15.6 11.1
Oct. 25 12.8 11.3
Nov. 22 11.6 11.1
Dec. 14 11.5 11.0
7.9
6.5
6.1
5.1
Significance •• **
«*
Cultivar (mean of all harvest and evaluation dates)
Gala 14.6 11.7
Mcintosh 11.1 10.6
4.3
8.5
Significance •• *
•
Storage (mean of all harvest and evaluation dates)
Paper 12.9 11.2
Plastic 12.8 11.1
6.5
6.4
Significance NS **
NS
" ,,NS Numbers within column and treatment grouping are signifi-
cantly different at odds of 99 to 1, 19 to 1, or not significantly different,
respectively.
Fruit Notes, Spring, 1990
100
80
60
40
20
Red color (%)
Oak
Mcintosh
100
80
60
40
20
U.S. Extra
♦ — • — •-
B
8/17 8/31 0/14 0/28 10/12 10/26 8/17 8/31 0/14 0/28 10/12 10/28
24
22
20
18
16
14
Flesh firmness (lbs)
12 1 —
8/17
16
14
13
12
11
10
Soluble solids (%)
8/31 0/14 0/28 10/12 10/26 8/17 8/31 0/14 0/28 10/12 10/26
Titratable acidity (meq/100ml)
10
e
-« — * — *-
200
150
100
60
nternal ethylene (ppm)
8/17 8/31 0/14 0/28 10/12 10/26 8/17 8/31 0/14 0/28 10/12 10/26
Figure 1. Changes in fruit quality parameters and characteristics of Gala and Mcintosh prior to, during
and after the normal harvest period: August 24 through October 19. A, red color, B, U.S. Extra Fancy;
C, flesh firmness; D, soluble solids; E, titratable acidity; F, internal ethylene.
Fruit Notes, Spring, 1990
Mcintosh had more red color than Gala (Figure 1).
Both cultivars continued to develop red color on succes-
sive harvest dates. Although Gala appeared to reach
the maximum red color of 80% in early October, Mcin-
tosh continued to develop red color to the last harvest
on October 19, when nearly 100% of the fruit surface
was judged to be red. The U. S. Extra Fancy grade was
denned for both cultivars as requiring 50% or more red
color, typical for the cultivar (although an official color
requirement has not yet been established for Gala).
Mcintosh developed typical red color earlier and
reached nearly 100% U. S. Extra Fancy before Gala.
However, by September 28, fruit from both cultivars
were nearly 100% U. S. Extra Fancy.
Gala fruit were firmer than Mcintosh on all har-
vest dates. Both cultivars had similar soluble solids
(sugar) levels when sampling was started, but Gala
accumulated sugars faster and ultimately had a signifi-
cantly higher sugar content. Titratable acidity of Mcin-
tosh was nearly twice as high as that of Gala on all
harvest dates. Acid content of fruit declined slightly
but not significantly for both cultivars over the 8-week
sampling period. Fruit internal ethylene concentra-
tions remained very low in all fruit on all harvest dates
through September 14, when increasing numbers of
Mcintosh fruit began producing large amounts of eth-
ylene. After September 14, Gala fruit produced ethyl-
ene but considerably less of it than did Mcintosh. The
pattern and rate of ethylene production in Mcintosh is
typical of many apple cultivars. The
rise in ethylene locates the exact time
of ripening and indicates a period
when harvest is appropriate. Since
Gala did not display this typical signal
of ripening it is not possible to com-
pare the time of ripening of Gala and
Mcintosh. However, based upon the
other quality parameters measured, it
appears that the time of ripening of
these cultivars is quite similar.
Storage and Taste Panel
Evaluation
of 10 apples each were placed in air storage at 32°F.
Fruit in the fourth bag, whether lined on not lined with
plastic, were evaluated at harvest for flesh firmness,
red color, soluble solids, and titratable acidity. A group
of apples from each harvest date that was stored in a
paper bag or in a plastic-lined paper bag was removed
from storage on October 25, November 22, and Decem-
ber 14 and flesh firmness, soluble solids, and titratable
acidity were determined. Fruit were peeled, sliced, and
subjected to a taste panel evaluation of between 24 and
32 individuals. Each taste panelist was asked on each
date to evaluate crispness, sweetness, acidity, and
overall rank of fruit from each of the 3 harvest dates
using a descriptive scoring test.
Gala fruit were firmer, had higher soluble solids,
and had lower titratable acidity than Mcintosh when
all harvest dates and all storage periods were consid-
ered (Table 1). With progressive harvest dates, soluble
solids increased, flesh firmness decreased, and ti-
tratable acidity remained unchanged for both culti-
vars. Flesh firmness dropped rapidly after harvest, but
the rate of loss slowed considerably in storage.
Gala was preferred to Mcintosh in taste tests when
all harvest dates and storage periods were considered.
Taste panelists rated Gala crisper, sweeter, and less
acid. The later the harvest date, the more the fruit were
preferred by taste panelists. The longer fruit were kept
in storage, the less taste panelists liked them.
Eighty fruit per tree were har-
vested from all quadrants of 3 Gala
and 3 Mcintosh trees on September
15, 22, and 29. On each datefruitwere
separated into 8 uniform groups of 10
apples each. Four of the groups were
placed in paper bags, and 4 were
placed in similar paper bags that were
lined with plastic. Three paper bags of
10 apples each and 3 plastic-lined bags
Per&ent^of initial weight
100
98
96
94
-$- Qala • papar
92
- Otlt • pintle
-©■ laelntoah • papar
O Uelnloah • plaalle
90
9i
9 10/7 11/4 12/2 12/30 1/27 2/24
Figure 2. Weight loss of Gala and Mcintosh fruit in air storage
at 32°F in either paper bags or plastic-lined paper bags.
Fruit Notes, Spring, 1990
Water Loss in Storage
Uniform samples of approximately 3000 g each
were selected from each cultivar. Half of the samples
were kept in paper bags while the other half were
placed in plastic-lined paper bags. All samples were
weighed and then placed in air storage at 32°F. Bags
were weighed every 2 weeks until February 28, 1989.
Fruit were examined at each weighing date to deter-
mine if any shriveling had occurred.
Fruit stored in plastic-lined paper bags lost consid-
erably less weight than those in paper bags (Figure 2).
Gala stored in paper bags lost more weight in storage
than Mcintosh and they lost it more rapidly. If placed
in plastic-lined paper bags, fruit of both cultivars lost a
comparable amount of weight.
Golden Delicious, one of the parents of Gala, com-
monly are stored in boxes lined with plastic. It appears
that Gala will benefit similarly from storage in plastic
since weight loss and shriveling can be reduced. In
previous years shriveling was noted in October in the
storage but not until December in this investigation.
The summer of 1988 was the hottest in 50 years in
Massachusetts. Perhaps fruit developed a thicker cu-
ticle and less permeable wax under these stressful
conditions, which might have helped reduce water loss.
Conclusions
There was a strong preference for Gala by taste
panelists. Gala does not exhibit excessive preharvest
drop, and it is precocious and productive. We conclude
that Gala is a very promising new cultivar that appears
to be a viable alternative for growers who wish to
replace Mcintosh or to plant a cultivar that has a broad
customer appeal.
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Pomological Note:
Blueberry Cultivar Update
Dominic A. Marini
Cooperative Extension, University of Massachusetts
Dr. James Hancock, Michigan State University,
presented a talk on blueberry cultivars at the New
England Small Fruit and Vegetable Convention, No-
vember, 1989. Here I will outline some of his major
points.
Dr. Hancock discussed cultivars from a number of
different aspects. For flavor, Darrow, Patriot, and
Spartan are preferred in Michigan. Bluecrop, Patriot,
Darrow, and Spartan are of the largest size. Bluetta,
Bluejay, Patriot, and Spartan are the highest yielding
early cultivars, while Bluecrop, Blueray, and North-
land are the heaviest yielding mid-season cultivars.
Elliot is very late and very high yielding. Darrow,
Elliot, and Lateblue have the most resistance to
mummy berry, while Bluecrop, Bluejay, Coville, Jer-
sey, and Spartan have moderate resistance. Suscep-
tible cultivars include Berkeley, Blueray, Bluetta, and
Collins. Blueray, Lateblue, Northland, and Patriot are
very winter hardy, while Bluejay, Bluecrop, Collins,
and Jersey are hardy. Bluetta, Berkeley, and Coville
are the least winter hardy. Spartan blooms early and
thus is more likely to be injured by frost. The bloom
season of other cultivars is directly related to the time
of harvest
On the basis of these characteristics Dr. Hancock
recommends the following cultivars:
Early season - Bluejay, Spartan, and Patriot (blooms
very early and could be hurt by frost);
Mid-season -- Blueray, Bluecrop, and Rubel;
Late season - Jersey and Elliot (may be too late in
cold areas).
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Fruit Notes, Spring, 1990
Commercial Potential of Red Fuji in
New England
Duane W. Greene and Wesley R. Autio
Department of Plant and Soil Sciences, University of Massachusetts
The apple cultivar that is in greatest demand for
planting in the United States is Fuji, including its red
coloring sports. Interest and popularity of Fuji has
preceded an appropriate and thorough evaluation of its
commercial potential. Our first evaluation of Fuji was
presented in Fruit Notes 54(1):10. It is the purpose of
this article is to give an update of our experience
growing and evaluating fruit of a strain of Red Fuji.
We obtained our Red Fuji from the New York
Agricultural Experiment Station in Geneva, and we
believe that it is the Akifu #1 strain. We began
propagating it 4 years ago and have harvested fruit
from these trees for the past 2 years at the University of
Massachusetts Horticultural Research Center in Bel-
chertown.
Tree Characteristics
Fuji is a vigorous, nonspur tree (Table 1). It is a
diploid that blooms mid- to late-season. Fuji is preco-
cious, but it also shows signs of biennial bearing that
starts at an early age. It has a spreading growth habit
with good crotch angles. After 4 years Fuji/M.9 is at
least 30% larger than adjacent Marshall Mclntosh/M.9
planted at the same time.
Table 1. Fuji fruit and tree characteristics.
Fruit characteristics
Tree characteristics
Firm
Very vigorous
Crisp
Spreading
Very sweet
Good crotch angles
Slightly aromatic
Precocious
Pink-red color
Biennial
Subacid
Diploid
Medium size
Good flavor
Slightly rough skin
Exeptional storability
Ripens before Rome
Fruit Characteristics
Fuji fruit are firm, crisp, very sweet, subacid, and
slightly aromatic (Table 1). Fruit are round to oblate,
medium in size, with a roughened skin. The standard
strain of Fuji has a pinkish red blush over a yellowish-
green ground color. The red coloring strains have
much more red that ranges from a cherry red to a
darker burgundy maroon. The fruit has good flavor
which improves after a period of storage.
The most notable characteristic of Fuji appears to
be its unequaled storage potential. There is no other
cultivar that we can grow in the Northeast that main-
tains condition and high quality in storage like Fuji.
In 1988, we harvested Red Fuji on October 24,
when flesh firmness averaged 18.5 lbs (Table 2). After
22 weeks in regular storage, flesh firmness averaged
16.5 lbs. It was noted that firmness could be catego-
rized according to fruit ground color. Fruit that had
green or green/yellow ground color had flesh firmness
of 19.0 and 16.4 lbs, respectively, and the quality was
still very good. Fruit with yellow ground color had flesh
firmness of 14.1 lbs and a bland taste.
Time of Ripening
The major factor limiting further planting of Fuji
in the Northeast is uncertainty about whether we have
a sufficiently long growing season to mature the fruit
properly. After the 1988 season it appeared that many
Table 2. Flesh firmness of Red Fuji
weeks of air storage (March 28, 1989).
firmness at harvest was 18.5 lbs.
after 22
Average
Ground
color
Flesh
firmness
Obs)
Green
Green/yellow
Yellow
19.0
16.4
14.1
Fruit Notes, Spring, 1990
Table 3. Influence of harvest date on ripening and fruit quality
of Red Fuji, 1989.
Harvest
date
Water-
core
(%)
Climacteric
fruit
(%)
Flesh Soluble
firmness solids
Gbs) (%)
October 6
October 13
October 18
60
60
30
25
19.1 14.1
20.4 14.7
18.7 15.5
fruit could have been harvested prior to October 24. To
confirm this result, sequential harvests were made in
1989, and maturity and quality were assessed (Table
3). The first harvest was made on October 6. Flesh
firmness was 19.1 lbs, red color was poor, and no fruit
had watercore; an indicator of the proper maturity to
harvest. Although soluble solids were 14.1, and starch
hydrolysis had started according to the starch-iodine
test, these fruit were not mature and harvest would
have been inappropriate. Red color developed dramati-
cally and to an acceptable intensity by October 13. Wa-
tercore had developed in 60% of the fruit and 30% were
climacteric, indicating that fruit were ripening and
harvest at this time was appropriate. Flesh firmness
was 20.4 lbs, soluble solids were 14.7%, and starch
hydrolysis continued to the point where some fruit had
no visible signs of starch present. By October 18, flesh
firmness and starch levels had declined further, sol-
uble solids had increased, and percent watercored and
climacteric fruit remained unchanged. October 13
coincided with the end of Golden Delicious harvest and
October 18 was just prior to the harvest of Rome.
The watercore shown by Fuji was not severe, and
probably it should not be considered a
negative feature. The watercore ap-
peared to dissipate in storage and no
breakdown developed; breakdown fre-
quently is associated with excessive
watercore at harvest.
Red Coloring Strains
There are many red-coloring
strains of Fuji that have been identified
but few of them are legally available.
Many will become available from the
IR-2 program in the near future. Red Fuji strains have
not been evaluated properly, so there is no good basis
for choosing one strain over another right now. Evi-
dence from Japan suggests that Fuji strains act differ-
ently under different environmental conditions, thus
making prediction of performance of individual strains
in our climate extremely tenuous. All Fuji strains are
in short supply. We believe that it is more important to
get a red-coloring strain and gain experience with it
rather than getting a specific strain whose perform-
ance is as yet unproven.
Conclusion
It is our conclusion that the season in Massachu-
setts is long enough in most locations to grow and
mature Red Fuji properly. Weather conditions in New
England may allow us to produce one of the most highly
colored Red Fuji apples in the United States. We feel
that Fuji will be an important apple cultivar in the
future and New England may be a favored place to
grow this apple that has exceptional shelf life and
storage potential.
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Fruit Noies, Spring, 1990
Preliminary Observations of Redmax
in Massachusetts
Wesley R. Autio, Duane W. Greene, and William J. Lord
Department of Plant & Soil Sciences, University of Massachusetts
New England is "Mcintosh Country"! We have the
environmental conditions which allow us to produce a
better Mcintosh than anywhere else in the country.
However, Mcintosh growers must consider altering
their management practices to cope with the loss of
Alar™. Summer pruning, detailed fertility manage-
ment, the use of NAA and ethephon, and increased
labor can all assist in expanding or altering the harvest
season so as to reduce losses from preharvest drop.
Likewise, detailed fertility management, accurate
maturity assessment, and careful fruit handling will
help maintain fruit quality. However, these changes
are short-term alternatives which will reduce only
some of the losses associated with not using Alar.
Growers must undertake appropriate long-term solu-
tions to overcome the need for Alar. Using dwarfing
1.0
0.6
o.o
-0.5
Log internal ethylene (ppm)
-1.5
-2.0
■2.5
Rogers
Marshall
Redmax
Figure 1. Internal ethylene concentration of
Redmax, Marshall Mcintosh, and Rogers Mcin-
tosh fruit harvested on September 7, 1988 and
September 26, 1989 from 7 replications planted in
1985 in Colrain, MA.
2.0
Log internal ethylene (ppm)
-A- Sumaarland
1.5
1.0
-% Rtdmil
0.6
-0.5
-1.0
-1.6
*£--"
8/30 9/6 0/13 9/20 9/27 10/4 10/11
Figure 2. Internal ethylene concentration of
Summerland Red Mcintosh and Redmax fruit in
1989. Fruit were from 5 replications of trees
planted in 1985 in Belchertown, MA.
rootstocks to decrease tree size, enhance fruit coloring,
expand ripening, and increase the rate of harvest can
help achieve this goal . Additionally, the harvest season
can be expanded by planting strains of Mcintosh that
differ in time of ripening or coloring.
As new Mcintosh acreage is planted or present
acreage is rejuvenated, growers must plan carefully
and establish a mix of strains which will give some
advancement as well as some delay of the harvest
season. Acey Mac and Pioneer Mac are reported to be
later ripening than standard Mcintosh, thus expand-
ing the late end of the harvest season. Alternatively,
Marshall Mcintosh, which ripens about 1 week earlier
than Rogers Mcintosh, allows an earlier beginning of
the harvest season. A relatively new strain of Mcin-
tosh, Redmax (Hilltop Trees, Hartford, Ml), has been
reported to be much earlier coloring than standard
Fruit Notes, Spring, 1990
100
90
ao
70
60
60
40
Red color (%)
Rogers
Marshall
Redmax
Figure 3. Red color of Redmax, Marshall Mcin-
tosh, and Rogers Mcintosh fruit harvested on
September 7, 1988 and on September 26, 1989
from 7 replications planted in 1985 in Colrain,
MA.
Mcintosh, possibly also allowing an advancement of
the harvest season. In this article we will detail some of
the early observations of Redmax in 2 plantings in
Massachusetts.
In 1985, Redmax/M.26 and Summerland Red
Mclntosh/M.26 were planted in a replicated trial at the
Horticultural Research Center (Belchertown, MA),
and Redmax/M.7A, Marshall McIntosh/M.7A and
Rogers McIntosh/M.7A were planted in a replicated
trial at Pine Hill Orchards (Colrain, MA). In 1988 and
1989 at Colrain and in 1989 at Belchertown, assess-
ments of fruit coloring and ripening were made.
Internal ethylene data from Colrain (Figure 1) and
from Belchertown (Figure 2) show that Redmax did
not ripen earlier than other strains, since the ethylene
accumulations were equivalent to those of standard
strains. The 1988 harvest in Colrain was made on
September 7 and Redmax had colored significantly
more than either Rogers or Marshall (Figure 3). The
1989 harvest was made on September 26, and at that
time Redmax and Marshall were colored to a similar
degree, and both were significantly more colored than
Rogers (Figure 3). In 1989, coloring of Redmax and
100
Red color (%)
a/30
9/6
9/13 9/20
9/27
10/4
10/11
Figure 4. Red color development of Summerland
Red Mcintosh and Redmax fruit in 1989. Fruit
were from 5 replications of trees planted in 1985
in Belchertown, MA.
Summerland in Belchertown was followed weekly
from September 6 through October 4 (Figure 4). On
September 6, Redmax fruit averaged 73% red, whereas
Summerland fruit averaged only 40% red.
Our observations have shown that Redmax clearly
is a "striper". On the poorly colored portions of fruit, a
stripe is evident. Some people may find this stripe
objectionable. In high coloring regions the degree of
coloring is so high that the stripe will not be a major
concern; however, this striping may be of some concern
where coloring conditions are less favorable.
It is clear from these data that Redmax is an early
coloring strain of Mcintosh; however, it does not ap-
pear to be an early ripening strain. Therefore, care
must be taken not to harvest Redmax when it is ade-
quately colored but not mature. However, we feel that
it still can be considered a strain which may advance
the harvest season. A high percentage of the Redmax
crop will be able to be harvested in the early portion of
the normal season with adequate color, thus leaving
few fruit on the tree for late-season harvests and for
loss to preharvest drop.
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Fwit Notes, Spring, 1990
Managing Small Fruit Crops for the
Retail Market
Marvin P. Pritts
Department of Pomology, Cornell University
The market for the small fruit grower is changing.
Pick-your-own (PYO) sales are either stable or declin-
ing, while demand for pre-picked fruit is growing. The
increase in per capita consumption of small fruits and
changing family priorities are fueling this demand.
Many growers find that they can no longer support
themselves through PYO sales alone, and must adapt
to this changing market situation. Growers should
begin to think in terms of producing a portion of the
crop for PYO, and the remainder for the retail or
wholesale market.
A tremendous opportunity exists for those willing
to take the extra steps that are required for meeting
new market demands. With some supervised harvest-
ing, a facility to remove field heat and keep berries cool,
a refrigerated truck, and a few phone calls, your berries
could be on supermarket shelves anywhere in North
America.
Marketing pre-picked berries requires better plan-
ning and management than growing for pick-your-own
because your job does not end when the berries get
ripe. Not only must berries be harvested under your
supervision, but they must be maintained in excellent
condition for delivery to the customer, who may be
miles away. Berries that are harvested in the field and
transported to the customer without special treatment,
will often arrive in an unacceptable condition. Al-
though small fruits are very perishable, there are
measures that can be taken to ensure a long shelf life,
some of which begin when the site is selected and
prepared for planting.
Preharvest Considerations
Cultivar selection has an important influence on
the quality of product in the market. Sparkle, Catskill,
and Del i te strawberries can no longer compete with the
firmer fruit of Allstar, Hobday, or Honeoye. Newburgh
is one of the firmer raspberries, and would be superior
to Reveille or Boyne for shipping or retail sales. Blue-
berry cultivars chosen for shipping should have a dry
scar. This means that the point of attachment to the
pedicel (fruit stem) should be brown after detachment,
and no white flesh should be observed. Cultivars with
good scars include Collins, Patriot, Blueray, Bluecrop,
and Coville. The skin of Bluetta, Herbert, and Lateblue
tends to tear when picked, exposing the sugary interior
of the berry to molds.
Selection of a site with good air drainage, and
planting in a row orientation parallel to the prevailing
summer winds will improve the quality of harvested
fruit. Proper plant densities will also reduce disease
pressure on fruit. Trellising brambles and pruning
blueberries will allow air movement and light in the
canopy so a less favorable environment is created for
decay organisms. Rain and dew increase the suscepti-
bility of infection, but this moisture will evaporate
quickly in a canopy with good air circulation. For
brambles and blueberries, trickle irrigation is better
than overhead irrigation, since the fruit is not wetted
during water application.
Proper fertilization is also an important compo-
nent of good shelf life. Fruit from plants that are
nutritionally stressed will have a shorter shelf life than
fruit from healthy plants. It is essential that adequate
potassium and calcium are available to the plant, and
that nitrogen is not too high. For example, a strong
relationship exists between nitrogen availability and
fruit softness in strawberry. A leaf analysis aids in fine-
tuning the fertilizer program.
Fungicides applied at petal fall will significantly
reduce the number of moldy berries in strawberries
and bramble fruit. Gray mold (Botrytis cinerea) read-
ily infects senescing petals and grows from them into
developing fruit before it ripens. Such berries may
have no visible signs of infection until harvest. Thus,
timely petal fall sprays are essential, especially during
cool, humid weather.
Some insects cause minor physical damage when
feeding on the fruit, but even small wounds are sites for
fungal infection. Certain insects may spread bacteria
and fungi from fruit to fruit. If insecticides are used to
control these pests, be sure to consider the days-to-
harvest restrictions.
Harvest Considerations
Blueberries are not as perishable as other small
fruit crops, and local berries have been sold in super-
markets for several years. A blueberry can remain on
Fruit Notes, Spring, 1990
the bush for more than a week after ripening without
spoiling. This fact has allowed the grower to guarantee
price, quantity, and delivery date to produce buyers up
to one week in advance, something which has been
difficult to do with raspberries and strawberries.
Raspberries and strawberries ripen quickly, so
harvesting the same planting frequently (once every
two days) is critical. Fruit harvested before it is fully
ripe will have a much longer shelf life than fully ripe or
overripe fruit. The optimum stage of maturity for the
raspberry occurs when the berry first becomes com-
pletely red, but before any darker hues develop. Straw-
berries with a white tip will retain their firmness much
longer than those harvested fully ripe, and will lose less
water during storage. Some training may be required
to teach pickers the proper stage and appearance for
harvesting.
Fruit quality for fresh market raspberries usually
declines as the season progresses. Be sure the market-
ing channels are open before the first berries ripen, as
these likely will have the highest quality and largest
size for the season.
Avoid touching a berry before it is ready for har-
vest. Place only undamaged berries with good appear-
ance in the pack. Studies have found that the magni-
tude of injury caused by human pickers can be so great
as to mask any other causes of deterioration.
Overripe berries are susceptible to mold. Once the
mold growing on overripe berries sporulates, large
amounts of inoculum will be present to infect other
ripening fruit. Overripe berries also attract ants,
wasps, and other pests. Do not dispose of rotten berries
near the field, and pick them off the bushes. It may be
more economical in the long run to pay pickers for
harvesting rotten as well as marketable fruit. One
could pay an hourly wage to a worker for harvesting
only rotten berries so the other pickers will not con-
taminate their marketable berries with fungal spores.
Harvest directly into small con-
tainers. Use half-pints for raspberries
and blackberries, and pints for the
other small fruit crops. Wide, shallow
containers are better than deep con-
tainers. Check with the buyer to deter-
mine what type of container is prefer-
able; each type has advantages and
disadvantages. The pulp containers
are inexpensive but stain easily.
Wooden containers also stain and are
expensive. Solid, clear plastic (polysty-
rene) containers will not stain and will
significantly reduce moisture loss
when used with a cap. In these con-
tainers, customers can see all the ber-
ries they purchase, and the containers are inexpensive;
however, juice can accumulate at the bottom of them.
It is difficult to cool berries in any of these types, and
mold tends to develop on the lower berries. The slitted
plastic containers allow for rapid cooling, do not stain,
and do not accumulate juice; however, if the slits are
too wide, berries can be damaged. A narrowly slitted,
plastic, half-pint container with a plastic wrap is often
used by large wholesalers.
Postharvest Considerations
Much time and effort can be expended to produce
and harvest a good crop of berries, only to have the crop
deteriorate before it is sold. This deterioration is
caused by respiration of the fruit. Respiration occurs in
all living organisms and is the process by which food
reserves are converted into energy. In a complex series
of reactions, starches and sugars are converted first to
organic acids, then to more simple carbon compounds.
Oxygen from the surrounding air is used, and carbon
dioxide and heat are released. Respiration of fruits
results in shrinkage and reduced sweetness. Raspber-
ries and blackberries have a higher respiration rate
than any other fruits, while strawberries follow closely
on the list (Table 1). Raspberries respire as much at a
freezing temperature as oranges do at room tempera-
ture. Conditions which slow the respiration process
are low temperature, high carbon dioxide, and low
oxygen in the storage chamber.
Temperature is the easiest and most effective con-
dition to modify for extended storage of fruits. Some
large shippers on the West Coast use a high carbon
dioxide atmosphere, and there have been some at-
tempts to use low oxygen storage, much like is done
with apples. In small fruits, however, bad-tasting
aldehydes and alcohols will accumulate in the fruit
when oxygen is limited. Work currently is being con-
Table 1. Respiration rates
(mg C0 2 /kg/hr) f
various
fruits
stored at different temperatures.
Commodity
1
remperature (°F)
32
41
50
59
68
Raspberry
24
55
92
135
200
Blackberry
22
33
62
75
155
Strawberry
15
28
52
83
127
Blueberry
10
12
35
62
87
Orange
3
5
9
15
24
Apple
3
5
8
13
20
10
Fruit Notes, Spring, 1990
ducted on overwraps that accumulate carbon dioxide
in the pack, but even this new technology is not very
effective without good temperature management
A 10°F reduction in temperature reduces the respi-
ration rate by approximately 50%. Furthermore, at
77°F and 30% relative humidity, fruit will lose water 35
times faster than it would at 32°F and 90% relative
humidity. Prompt cooling, and maintenance of proper
temperatures and humidity, are essential.
The cooling process should occur in two stages.
Simply setting harvested berries in a cold room is not
adequate because the field heat is not removed fast
enough. Rapid movement of cold, humid air through
the berries is essential during the first few hours after
harvest. Brokers contend that for every hour delay in
cooling, shelf life is reduced by one day. Growers can
take advantage of night cooling by harvesting fruit as
early in the morning as possible.
Large growers may have a separate pre-cooling
facility specifically designed for removing the field heat,
but inexpensive, effective improvisations can be
adapted for any cold storage. If a grower only has a
walk-in cooler, recently picked flats of berries can be set
into a cardboard box which is opened at both ends. A
household fan is then placed at one end of the box to
draw air through the flats. Once the berries are cool,
flats are removed from the cardboard and wrapped in
plastic. The plastic will reduce water loss during
storage, and prevent condensation on the berries when
flats are removed from the cooler. The plastic should
not be removed until the temperature of the berries
warmsto nearthe temperature of thedisplay. Conden-
sation will then form only on the outside of the plastic,
while the berries inside will remain dry.
The storage room itself can be maintained as low as
30°F. Berries will not freeze at or above this tempera-
ture, because the sugars in the fruit depress the freez-
ing point. One may want to maintain the storage at a
slightly warmer temperature (32°F) to allow some
room for error. Major shippers, however, report that
storage at 40°F reduces shelf life by 50% compared to
30°F.
The selection of a cooling unit is very important
when designing a cooler. If the temperature difference
between the air and the cooling unit is large, then the
condensers will accumulate ice from moisture in the
air. This drying of the air would not cause a problem for
dry goods, but will severely dehydrate fruit. The at-
mosphere around the fruit should be humid to prevent
shrinkage, so a cooler should be selected which can
maintain a relative humidity of 90-95% at 32°F. These
types of coolers are more expensive and less common
than those for dry goods. Consult your agricultural
engineering specialist for help with selecting a cooling
unit and building a storage facility.
Transporting Berries to Market
The loss of soft fruits such as raspberries and
strawberries from harvest to the consumers table is
estimated at more than 40%. A 14% loss occurs from
farmer to wholesaler, a 6% loss occurs from wholesaler
to retailer, and 22% is lost between the retailer and
consumer. Much of these losses are due to poor han-
dling of berries after harvest.
There are many steps in the distribution chain
which can negatively affect fruit quality. A typical
handling scheme might be transporting berries from
the field to the pre-cooler, wrapping flats after pre-
cooling, loading them into a refrigerated truck, trans-
porting to a distribution center, unloading into the
warehouse, loading into a truck, transporting to retail
store, unloading, handling in the backroom, and set-
ting up the display. Mishandling at any point along this
route can result in unacceptable berries.
You should work to minimize the number of han-
dling steps from field to display. Berries should remain
cold and wrapped during each phase of transportation.
Never allow the berries to sit on u n refrigerated loading
docks. When loading a truck, stack flats on a pallete
and away from the walls. Ensure that cold air is free to
circulate around the sides of the pallete and across its
top and bottom. When flats of fruit are allowed to touch
the floor or side walls, temperatures in the flats can rise
as much as 20°F. Do not stack flats directly over the
rear wheels, and use strapping or stretch film to stabi-
lize the load. Refrigerated trucks should be equipped
with air-suspension systems rather than spring sys-
tems to reduce transit vibrations.
Most mechanical refrigeration equipment in cur-
rent use is designed to maintain temperature, but lacks
the air flow and refrigeration capacity for rapid cooling.
Temperature regulating equipment in trucks does not
have the accuracy to achieve temperatures below 40°F
without danger of freezing. Furthermore, high density
loads are used to minimize transportation costs, but
this practice inhibits cooling during transit. Thorough
product cooling before loading is very important.
Allow berries to warm only when they are ready for
display to consumers, and before removing the plastic
wrap over the flats. Any condensation will then form
on the plastic wrap rather than on the berries inside.
Often the transportation of berries is beyond the
control of the grower. To develop new and distant
markets, receivers must be educated in proper han-
dling procedures. Personal contact with the receiver
Fruit Notes, Spring, 1990
11
before the first delivery is often useful. In other cases,
handling instructions may be attached to the flats.
By using proper harvesting and storage tech-
niques, it is possible to maintain quality raspberries for
7 days after harvest, and strawberries for 2 weeks.
Blueberries can be maintained for 3 weeks after har-
vest. This amount of time is certainly enough for
growers to take advantage of distant markets through-
out North America.
Supplemental References
Hardenburg, R. E., A.E. Watada, and C.Y. Wang. The
Commercial Storage of Fruits, Vegetables, and Florist
and Nursery Stocks. USD A, Ag Handbook 66. (Write
to Superintendent of Documents, Government Print-
ing Office, Washington, DC 20402).
Bartsch, J. Walk-In Cooler Construction. Cornell Ag
Engineering Bulletin #453. (Cost $0.80, Distribution
Center, Cornell University, Ithaca, NY 14850).
Bartsch, J. and G.D. Blanpied. Refrigerated and Con-
trolled Atmosphere Storage for Horticultural Crops.
NRAES-22 (Write to NRAES, Riley-Robb Hall, Cor-
nell University, Ithaca, NY 14853).
Pritts, M.P., K.A. Worden, and J.A. Bartsch. Factors
Influencing Quality and Shelf Life of Eastern Straw-
berry Cultivars. Ag. Engineering Staff Report 87-1.
(Free. Write to Department of Pomology, Cornell
University, Ithaca, NY 14853).
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Food for Thought
Dominic A. Marini
Cooperative Extension, University of Massachusetts
R. Bruce Smith of Longview Farm, Westmoreland,
NH, was one of the speakers on "value added products"
during the marketing session at the 1989 New England
Small Fruit and Vegetable Growers Convention and
Trade Show. Mr. Smith operates an apple orchard and
gave a very frank and forthright talk on pies as a value
added product, including some of his figures on costs
and returns.
His cost of production for the wholesale market is
$5 per bushel and the average selling price is $7 per
bushel. Cost of production for pick-your-own or for his
roadside stand is $8 per bushel, while returns are $12
per bushel for pick-your-own and $18 per bushel on the
stand.
He averages 10 pies per bushel. It costs $4 to
produce a pie which sells for $6.25 on the stand. He
produces 2000 pies per week for wholesale, mostly to
farm stands and to 2 supermarkets. Pies are sold either
baked or not baked and frozen.
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12
Fruit Notes, Spring, 1990
Peach Cultivars
Karen I. Hauschild
Cooperative Extension, University of Massachusetts
Peaches are not new to growers in southern New
England: however, it is difficult to keep abreast of new
cultivars. At the University of Massachusetts, with the
help of funding from the Massachusetts Fruit Growers'
Association, we have initiated a program of evaluating
new peach cultivars. In this article I will describe some
of the cultivars in our plantings, based on information
from other locations across the country.
This evaluation began in the spring of 1989 with
the planting of 9 cultivars at commercial orchards. The
test cultivars in those plantings are listed below.
Jersevdawn . Fruit are semi-freestone, large, good
quality, firm, and attractive. Fruit ripen early, just
after Garnet Beauty. Trees are vigorous, hardy, pro-
ductive, with good resistance to bacterial spot. Jersey-
dawn fruit have few split pits.
Newhaven . This tree is a reliable cropper, very like
Redhaven. Fruit have better size than Redhaven, with
firm, juicy flesh. Flesh does not brown. Trees are
productive and strong and very resistant to leaf spot.
Madison . This tree is vigorous and hardy. The fruit,
however, do not handle or ship well. Trees are produc-
tive, and flower buds are very hardy. Fruit are free-
stone, and ripen in early September. This cultivar is
recommended primarily for local markets.
Jim Dandee ™. This is a hardy, midseason cultivar.
Fruit are freestone, firm, and similar to Redhaven, but
size better. Fruit have excellent shipping quality. Tree
has medium vigor. This peach has been rated one of the
best all around in its season.
Encore ™. This cultivar is late. The tree is strong and
winter hardy. Fruit are large, red over yellow, and
ripen in late September. Fruit are freestone and toler-
ant of bacterial spot. (This cultivar may not ripen in
colder areas of the region.)
Other cultivars included in the 1989 plantings
were Redhaven, Cresthaven, Jayhaven, and Jerseyglo.
These cultivars are well known in New England and
have the following characteristics.
Redhaven . The medium-sized fruit are highly colored,
attractive, and have firm flesh and fair flavor. The tree
is very productive, and requires heavy thinning. Flesh
does not brown, and trees are winter hardy. This
cultivar is considered the "standard" in New England.
Cresthaven . Fruit are large and oblate-shaped, with a
dark-red blush. The bright yellow flesh is firm, juicy,
and slightly fibrous. There is some red at the pit. The
flavor is very good. The tree is vigorous, productive,
and medium in hardiness. This cultivar is also fairly
tolerant of bacterial spot.
Jayhaven . Fruit are medium to large, round, bright
colored, and freestone. The flesh is yellow and melting.
Trees are more bud hardy than Glohaven. Trees are
productive, and fruit ship well.
Jerseyglo . Fruit are large, attractive, and freestone.
The flesh is yellow and firm. Trees are vigorous and
productive, and about equal to Redhaven in bud hardi-
ness. Fruit are described as being exceptionally resis-
tant to bacterial spot.
Additional cultivars that we will plant at the Hor-
ticultural Research Center in 1990 include those listed
below.
Flavorcrest . Fruit are red, very firm, and ship well.
NJ275 . Fruit are medium to large, yellow-fleshed, and
have good color and firmness. Trees are productive,
resistant to bacterial spot, and cold hardy.
Fayette . Trees produce round, freestone fruit with
little fuzz. Flesh is firm, smooth, and of good quality.
This is a good late-season shipper. Trees are vigorous.
(This cultivar may not be suitable for colder locations.)
White Lady . Fruit are medium-sized, very round,
attractive, and very firm. This cultivar is probably the
best white peach for handling and shipping.
Summer Pearl ™. Freestone fruit are medium to large,
with firm, white flesh, and ship well. Trees are re-
ported to be as hardy as Redhaven and moderately
resistant to bacterial spot.
In addition to the aforementioned cultivars, we will
also be planting at least 2 other peach and 3 nectarine
cultivars in 1990. We will be evaluating all of these
cultivars for hardiness, fruit quality, and productive-
ness.
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Fruit Notes, Spring, 1990
13
Effectiveness of Dimilin™ Against Apple
Blotch Leafminers
Ronald J. Prokopy, Susan L. Butkewich, and Margaret Christie
Department of Entomology, University of Massachusetts
In a previous issue of Fruit Notes [52(1):12-15] we
reported on one year of preliminary trials using Dimil-
in™ against apple blotch leafminers (ABLM) in com-
mercial apple orchards. Dimilin is an insect growth
regulator which inhibits chitin synthesis, particularly
in the egg stage of ABLM. It has a long residual activity
and is reported to be relatively non-toxic to beneficial
predators, reducing the risk of mite buildup associated
with use of synthetic pyrethroids, Vydate™, or Lan-
nate™ against leafminers. Here, we report on 3 years
of trials (1987, 1988, and 1989) of Dimilin against
ABLM in several commercial apple orchard blocks.
In our trials, Dimilin 25 WP was applied by grow-
ers to orchard blocks 2 to 3 acres in size. On opposite
ends of each block, approximately 20 trees (10 at each
end) were left unsprayed to serve as checks. The only
other insecticides used in any of the test blocks were
Imidan™ or Guthion™, to which ABLM are resistant.
Against first-generation ABLM, Dimilin application
occured at tight cluster to early pink, timed to coincide
with the onset of ABLM oviposition. Against second-
generation ABLM, Dimilin application occured in
summer Gate June or early July), timed to coincide
with the peak of second-generation adult emergence
from pupae. In all cases, only a single pre-bloom appli-
cation (16 oz/acre in 1987, 8 oz/acre in 1988 and 1989)
or a single summer application (same rates as for pre-
bloom) was made.
The results (Table 1) indicate that in 1987, trees
treated with Dimilin at 16 oz/acre before bloom aver-
aged only one-fourth as many first-generation mines as
untreated trees. In 1988, trees treated pre-bloom with
Dimilin at 8 oz/acre averaged only about one-sixth as
many first-generation mines as untreated trees. In
1989, however, trees treated prebloom with Dimilin at
8 oz/acre averaged nearly one-half as many first-gen-
eration mines as untreated trees. The very frequent
and heavy rains from tight cluster through pink in 1989
may have reduced the residual activity of Dimilin, so
that the pesticide was considerably less effective than
in 1987 or 1988. Where Dimilin was applied in summer
against second-generation eggs, only one-fourth (1987)
to one-sixth (1988) as many mines were present on
Dimilin-treated trees as on untreated trees.
In conclusion, our findings suggest that a single
well-timed application of Dimilin, either pre-bloom or
in summer, can be very effective against ABLM, pro-
vided rainfall is not excessive following application.
Possibly, split applications (4 oz/acre twice or 2 oz/acre
three times) either pre-bloom or in summer would
Table 1. Effect of a single application of Dimilin 25WP on ABLM in commercial apple orchards.
In each orchard, 10 leaves per tree on approximately 20 trees treated with Dimilin and 20
untreated trees were sampled for presence of first- or second-generation mines.
Year
Number
of
orchards
Treatment
period
Rate of
formulated
Dimilin/acre
t
<\vg. % leaves with ABLM mines
First generation
Second generation
Dimilin
Untreated
Dimilin
Untreated
1987
1988
1989
1987
1988
6
10
14
5
1
TC-EP
TC-EP
TC-EP
Summer
Summer
16 oz.
8oz.
8oz.
16 oz.
8oz.
0.01
0.70
5.14
0.04
4.60
13.72
0.05
8.00
0.22
48.00
14
Fruit Notes, Spring, 1990
reduce potential adverse effects of rainfall on the resid-
ual activity of Dimilin. Pre-bloom application has the
added advantage of being effective against a range of
first-generation leafroller larvae which are active at
that time, but which are in the pupal stage (unaffected
by Dimilin) in late June and early July.
For the past 3 years, Massachusetts has received
an Experimental Use Permit (EUP) for several
hundred acres worth of Dimilin use each year on
apples. We have been much more fortunate than other
states in this regard. Still, we are hopeful for full
registration of this effective, relatively environmen-
tally safe compound in the near future.
Acknowledgements
We are grateful to Paul Bohne and Uniroyal
Chemical Co. for supporting this work. We also thank
all cooperating growers.
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Evaluation of Dimilin™ Against Pear Psylla
Ronald J. Prokopy, Susan L. Butkewich, and Mararet Christie
Department of Entomology, University of Massachusetts
In the preceding article, we reported on trials of
Dimilin™ for control of apple blotch leaf mi ne r . In this
article, we report on tests of Dimilin used with oil
against pear psylla. This insect is more difficult to con-
trol than any other pear pest. Nationwide, it has
developed at least some resistance to nearly every
pesticide to which it had been exposed during regular
orchard treatments. Because Dimilin disrupts insect
growth rather than being acutely toxic, it represents a
new form of pesticide not previously encountered by
pear psylla.
All of our trials were conducted over 3 years (1987-
89) in commercial orchards. Growers applied the
Dimilin and/or oil with their own sprayers. Test blocks
averaged 1 to 2 acres in size, with Dimilin and oil
applied to all trees except 1 to 12 trees left as untreated
checks at each end of the block. On each sampling date,
10 watersprouts on each of 20 treated and 20 untreated
trees were examined for presence or absence of live
psylla nymphs or adults.
In 1987, oil was applied pre-bloom to all test blocks.
Dimilin at 16 oz per acre was applied only post-bloom,
twice per block in May or June. In 2 orchards where
psylla populations were high or moderate (Orchards A
and B), Dimilin had little effect (Table 1). In Orchard
C, where psylla was relatively low, Dimilin maintained
the population at a low level through mid- July.
In 1988, oil was applied once and Dimilin twice at
8 oz per acre pre-bloom in 2 orchards. Where there was
a moderate population of psylla (Orchard A), control
through mid-June was fair at best (Table 1). Where
psylla was rather low (Orchard B), control through
mid- June was good. In Orchard C, oil was applied once
and Dimilin once at 12 oz per acre pre-bloom. Then
Dimilin was applied twice postbloom at 12 oz per acre.
The psylla population remained low on treated trees
through mid-July. Orchard D had a very high psylla
population. Two pre-bloom treatments of oil plus
Dimilin at 12 oz per acre together with a post-bloom
treatment of each in late May failed to show any
reduction in psylla when sampled in mid- June.
In 1989, oil together with Dimilin at 12 oz per acre
was applied twice pre-bloom in 2 orchards. In Orchard
A, where Dimilin alone at 12 oz per acre was also
ap plied post-bloom in late May, treated trees were free
of psylla in mid- June. In mid- July, trees had relatively
low numbers of psylla (in contrast to rather high
numbers on the checks). In Orchard B, where the
psylla population was high, treated trees had rather
low psylla populations in mid- June but fairly high ones
by mid-July.
Together, these results suggest that Dimilin may
indeed be an effective pesticide against pear psylla, but
only if a sufficient number of pre-bloom applications
are made. Treating with Dimilin strictly post-bloom
seems to have little positive effect. The best results
(1989 in Orchard A) were obtained where Dimilin was
applied with oil twice pre-bloom (mid and late April)
and again shortly after petal fall. However, even this
usage pattern had no effect where treatment was not
begun by mid-April (Orchard D in 1988). One caution-
ary note in the interpretation of our results is the lack
Fruit Notes, Spring, 1990
15
Table 1. Effect of Dimilin 25W on pear psylla. Bloom occurred about May 7 in 1987, May 15 in 1988
and May 14 in 1989.
Year Orchard
Treatment
Rate of
formulated
material/acre
Percent of terminals infested
Treatment
dates
June 11
July 13
1987 A
B
1988
1989
B
B
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
Dimilin
Oil
Untreated
16 oz
4gal
16 oz
4gal
16 oz
4 gal
8oz
3 gal
8oz
3gal
12 oz
3 gal
12 oz
4gal
12 oz
6 gal
4gal
12 oz
8gal
5/15, 5/22
4/20
6/19, 6/29
4/16
6/19, 6/29
4/24
4/14, 5/5
4/21
4/14, 5/5
4/21
4/21, 5/23, 6/3
4/21
4/26, 5/4, 5/23
4/26, 5/4, 5/23
4/14, 4/26, 5/25
4/14
4/26
4/26, 5/10
4/26, 5/10
100
100
June 16
53
76
3
15
5
24
97
99
June 12
31
14
92
57
75
11
34
July 15
4
12
July 12
26
71
63
87
16
Fruit Notes, Spring, 1990
of control treatments in which oil alone was applied . If Acknowledgements
an Experimental Use Permit for Dimilin continues to
be granted for use on pears in Massachusetts, as it was
in 1988 and 1989, we encourage growers who have had
trouble controlling psylla to try using Dimilin, pro-
vided they are willing to make 2 pre-bloom applications
at 12 oz per acre (together with oil) beginning in early
or mid-April and a post-bloom application in late May.
We thank Paul Bohney and UniRoyal Chemical
Co. for supporting this work. We also thank all of the
participating applicators: Stanley Baj of Atkins Farm
in Belchertown, Keith Bohney of Westford, David Ch-
eney of Brimfield, and Tony Rossi of the Horticultural
Research Center in Belchertown.
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Advancements in Second-stage Apple IPM:
Substituting for "Sticky" on Baited Red
Spheres
Jian Jun Duan, Max P. Prokopy, Patricia Powers,
and Ronald J. Prokopy
Department of Entomology, University of Massachusetts
Recently, we reported results of a 3-year pilot
project in commercial apple orchard blocks using sec-
ond-stage IPM techniques [Fruit Notes 55(l):4-9]. One
of the keystone practices was the use of sticky red
spheres baited with synthetic apple odor to intercept
immigrating apple maggot flies (AMF) on perimeter
apple trees before they could penetrate the orchard
interior. We concluded that for such an interception
system to be successful on a broad-scale commercial
level, certain improvements would be necessary. One
improvement concerned enhancing the attractiveness
of the red spheres, results of which are reported in
FruitNotes 54(4):18-19. Here, we describe initial tests
aimed at replacing the sticky coating used in capturing
and killing AMF with a mixture containing a fly feeding
stimulant, a pesticide, and a residue-extending agent.
Our hope is to discover an effective mixture of these
components so that a fly alighting on a treated sphere
would be stimulated to feed and thereby ingest enough
pesticide to be killed rapidly, before it could lay eggs.
Methods Used
All tests reported here were carried out in the
summer of 1989. A potted apple tree was placed in each
of 2 large field cages. Two unbaited, 8-cm, red spheres
of the same treatment were hung on each tree. For
each trial, a mature AMF male was released on a leaf
midway between the spheres and followed until it
visited a sphere, left the tree without visiting a sphere,
or else 5 minutes had elapsed without the fly visiting a
sphere. The length of each visit was recorded. After
departing a sphere, the fly was captured and kept in a
laboratory cage to determine whether it was alive or
dead after 24 hours. We tested males because females
were used in other projects and thus were not avail-
able. This fact may be a shortcoming of the work
reported here, because we want to control females in
orchards.
Fly Feeding Stimulants
Table sugar (sucrose) and corn syrup (sucrose plus
some other types of sugar) are known to be excellent
feeding stimulants for house flies. In preliminary
laboratory tests, we found that both stimulated AMF to
feed, as long as the concentration was 2% or greater.
Hence, we used one or the other in mixture with
pesticide and residue-extending agent in our field cage
tests. Presently we are conducting laboratory tests in
search of even more effective feeding stimulants.
Pesticides
In our first experiment, we evaluated the effective-
ness of 4 pesticides currently labelled for orchard use:
the synthetic pyrethroids Pounce™ 3.2 EC and As-
ana™ 1.9 EC, the organophosphate Guthion™ 50 WP,
and the carbamate Lannate™ 1.8 SL. These materials
are among the most insect-toxic members of the 3
Fruit Notes, Spring, 1990
17
Table 1.
Response of male AMF to red wooden spheres treated with fly feeding stimulant, pesticide, and resi-
due-extending agent. Spheres were hung from potted apple trees in a
ield cage for testing.*
Active
No. days
Visiting
ingredient
from
AMF that
Visiting
in mixture
treating
AMF
Average
died while
AMF that
applied to
sphere
Number
visiting
duration
on a
died within
spheres
until
of AMF
a sphere
of a visit
sphere
24 hours
Expt.
Treatment
(%)
testing
released
(%)
(seconds)
(%)
(%)
1
Pounce 3.2 EC
0.5
6
36
58 a
131 ab
0b
5b
Asana 1.9 EC
0.4
6
29
62 a
189 a
0b
b
Guthion 50 WP
2.7
6
41
47 a
111 ab
b
10 b
Lannatel.8SL
6.0
6
32
63 a
54 b
40 a
60 a
Untreated
--
-
34
59 a
153 ab
0b
b
2
Guthion 1.8 EC
6.0
12
27
74 a
48 a
5b
25 b
Lannate 1.8 SL
6.0
12
31
64a
63 a
10 b
35b
Lannate Tech
2.0
12
28
71 a
36 a
60 a
70 a
Untreated
--
--
33
61 a
71 a
0b
0c
3
Lannate 1.8 SL
4.0
1
27
74
53
80
80
(( CI
u
5
29
69
36
80
85
ii CI
<*
12
30
67
69
70
75
l( tt
a
21
30
67
76
50
55
Lannate Tech
4.0
1
29
69
60
85
85
CI a
cc
5
27
74
46
80
85
CI (t
(t
12
29
69
45
80
80
(( CI
CI
21
28
71
55
50
65
•Values
in each experiment not followed by the same letter are significantly different at odds of 19 to 1.
major classes of orchard-labelled insecticides. For this
test, we introduced each pesticide at 100 times the
maximum orchard-recommended rate into an aqueous
mixture of 2% table sugar and 0.3% Vaporguard™
(used here as a residue-extending agent, obtained from
Miller Chemical Co., Hanover, PA). Red-painted,
wooden spheres were dipped in each mixture, hung out
to dry under protection from rainfall and sunlight, and
tested 6 days later.
The results (Experiment 1 of Table 1) show that
just as high a proportion of released AMF (about 60%)
visited spheres treated with Pounce, Asana, or Lannate
as untreated spheres (without sugar, pesticide, or
Vaporguard). A somewhat lesser proportion (47%)
visited spheres treated with Guthion, possibly owing to
the whitish residue of the wettable powder that par-
tially obscured the red color of the sphere. Of the
visiting AMF, 60% of those from Lannate died within
24 hours, compared with 10% or fewer of those from
any other treatment.
In our second experiment, we evaluated the effec-
tiveness of Guthion 1.8 EC, Lannate 1.8 SL, and Lan-
nate technical powder. The Guthion EC and Lannate
SL were used at 100 times the orchard recommended
rate and were mixed in the same proportion with other
ingredients as in the first experiment. As before,
spheres were dipped in these mixtures. The Lannate
technical was mixed at a rate of 2% powder with 56%
table sugar, 20% ethanol, 20% water, and 2% of a
polymeric thickener (a residue extending agent). This
mixture (in paste form) was brushed onto spheres. All
spheres were protected from sunlight and rainfall for
12 days, and then tested.
The results (Experiment 2 of Table 1) show that
just as great a proportion of released AMF (about 60 to
70%) visited each type of treated sphere as untreated
spheres, indicating no reduction in AMF attractiveness
to spheres as a consequence of treating with pesticide.
Of the visiting AMF, 25 and 35% of those from Guthion
EC and Lannate SL, respectively, and 70% of those
18
Fruit Notes, Spring, 1990
from Lannate technical, died within 24 hours.
In our third experiment, we evaluated the residual
effectiveness of Lannate SL and Lannate technical.
Mixtures contained 4% active ingredient of each. For
this test, Lannate EC (16% formulated material) was
mixed with 58% corn syrup, 13% ethanol, 13% water,
and 0.3% Vaporguard. Lannate technical was mixed
with 10% table sugar and 86% of a polymeric thickener.
All spheres were kept under protection from rainfall
and sunlight until tested at 1, 5, 12, and 21 days after
treatment.
The results (Experiment 3 of Table 1) show that
both formulations of Lannate yielded 55 to 65% kill
(within 24 hours) at 21 days. Interestingly, nearly all
deaths occurred while AMF were still on a sphere and,
on average, within a minute or so of fly arrival on a
sphere.
Together, the results of these 3 experiments indi-
cate that Lannate was more effective than Pounce,
Asana, or Guthion in killing AMF that alight on a
treated red sphere. Under protected conditions, the
residual effectiveness of Lannate remained high at 3
weeks, with half of the AMF dying within a minute or
so after landing on such a sphere 3 weeks after treat-
ment.
Residue-extending Agents
Several possibilities emerged in our search for
ways to extend the residual effectiveness of fly feeding
stimulants and pesticides on spheres.
One way involved protecting the sphere with a
conical cover in the shape of a traditional Chinese hat.
We constructed cones (16 cm in rim diameter) of green
cardboard, yellow cardboard, or clear acetate. The
peak was fixed at 2 cm above a sphere, with the rim
extending mid-way down the sphere and
about 4 cm from the sphere surface. We
reasoned that cones of this size would pro-
vide excellent protection of a sphere against
rainfall, while allowing the entire lower half
of the sphere surface to remain fully exposed
to fruit-seeking flies. Each sphere was
coated with tangletrap and was baited with
a single polyethylene vial that contained
synthetic apple odor (butyl hexanoate) re-
leased at about 700 apple equivalents per
hour. All spheres were hung in a commer-
cial apple orchard.
As shown in Table 2, irrespective of
whether the vial of odor bait was 15 cm
above, 15 cm to the side, or 15 cm beneath a
sphere, none of the 3 types of cone-covered
spheres captured even half as many AMF as
comparably baited unprotected spheres.
Hence, although a cone protects a sphere against run-
off of pesticide during rainfall, it cuts down on arrivals
of AMF to an unacceptable level.
Another way we envisioned of extending the resid-
ual life of fly feeding stimulant and pesticide on a
sphere was to envelop the sphere in a cotton red sock
(much like a Fenway Park red sock) which would be
more absorbent than the smooth surface of a painted
wooden sphere. Better yet, we hypothesized, why not
replace the wooden sphere inside a red sock with a
sphere of sawdust or the liner from a disposable baby
diaper formed into a sphere? These would absorb a
great deal of liquid pesticide mixture and possibly
afford continued release over a very long period. We
therefore constructed red spheres of these types, using
socks the same color as our red-painted wooden
spheres and having 60 strands of fiber per cm. We
dipped them until saturated in a mixture containing
16% Lannate 1.8 SL (4% active ingredient), 58% corn
syrup, 0.3% Vaporguard, and 26% water. Half of the
spheres in each treatment were continuously protected
from sunlight and rainfall. The remaining half were
hung from tree branches and thereby exposed continu-
ously to the weather. All spheres were tested 21 days
after dipping.
As shown in Table 3, the proportion of AMF visit-
ing red sock-covered diaper, sawdust, or wooden
spheres was consistently slightly less (45-57%) then
the proportion visiting smooth red wooden spheres
(59-67%). Among spheres protected from weather
over the 21 day pre-test period, 55% of AMF that visited
smooth wooden spheres died within 24 hours com-
pared with only 25, 15, and 20% deaths among AMF
that visited red socks enveloping a diaper, sawdust, or
a wooden sphere, respectively. Moreover, in the case of
spheres exposed to the full range of weather conditions
Table 2. Total AMF females captured on odor-baited sticky
red spheres protected from rainfall by green, yellow, or clear
plastic cones above the spheres and hung in apple trees
(July 2 to August 3, 1989).*
Color of
protective
cone
Position of odor vial relative to sphere
15 cm
above
15 cm
to side
15 cm
below
Green
Yellow
Clear
No Cone
8b
20 b
21 b
75 a
4 b
11 b
29 b
70 a
6b
7b
14 b
56a
•Four replications per treatment. Values not followed by
the same letter are significantly different at odds of 19 to 1.
Fruit Notes, Spring, 1990
19
Table 3. Response of male AMF to 8-cm spherical baby diaper liners, sawdust, or wooden spheres
enveloped by a
red cotton sock, or to smooth red-painted wooden spheres. All spheres were
dipped in a
mixture of corn
syrup, Lannate SL, and Vaporguard, and kept under
protected conditions or exposed in a
tree for 21 days until hung
from potted apple trees in a field cage for testing.*
Visiting
Visiting
AMF that
AMF that
AMF
Average
died while
died
Dipped in
Number of
visiting
duration
on a
within
Type of
pesticide
Exposure to
AMF
a sphere
of a visit
sphere
24 hours
sphere
mixture
environment
released
(%)
(seconds)
(%)
(%)
Sock/diaper
yes
Protected
35
57 a
31 b
15 ab
25 ab
Sock/sawdust
yes
k
42
48 a
22 b
10 ab
15 be
Sock/sphere
yes
«
37
54 a
52 b
10 ab
20 be
Smooth sphere
yes
«
31
64 a
46 b
35 a
55 a
Smooth sphere
no
tt
34
59 a
110 a
0b
c
Sock/diaper
yes
In Tree
36
56 a
35 b
0b
c
Sock/sawdust
yes
tt
44
45 a
48 b
b
c
Sock/sphere
yes
tt
41
49 a
110 a
b
c
Smooth sphere
yes
u
30
67 a
60 ab
25 a
30 ab
•Values not followed by the
same letter are significantly different at odds of 19 to 1.
over the 21-day pre-test period (including 15 cm of
rainfall), 30% of AMF that visited a smooth wooden
sphere died within 24 hours compared with 0% deaths
among AMF that visited sock-covered spheres. Obvi-
ously, our idea that using an absorbent material such
as a cotton red sock to reduce residue decay was not a
fruitful one. It appeared to us that arriving AMF were
rather reluctant to feed when on a sock-covered sur-
face, possibly owing to an adverse effect of the mesh of
cotton fiber on fly foraging behavior. We are very
encouraged, however, by the substantial rate of mor-
tality of AMF that arrived on smooth, painted, wooden
spheres exposed to a high level of rainfall over the 21-
day pre-test period. It seemed that after drying, the
Vaporguard-corn syrup mixture formed a rather hard
glaze on the sphere surface and thereby afforded con-
siderable protection against residue decay.
We made no clear-cut comparisons between Va-
porguard and a polymeric thickener as residue-extend-
ing agents. Vaporguard had the advantage that both
liquid and powdered fly feeding stimulant and pesti-
cide can be mixed with it. We suggest, however, that
polymeric thickener, which is miscible only with pow-
dered fly feeding stimulant and pesticide and forms a
hard glaze after drying, will prove the more effective
under heavy rainfall.
Conclusions
We are most encouraged by the results of our first
summer of research evaluating mixtures of fly feeding
stimulants and pesticides and ways of protecting such
mixtures against residue decay. Our combined find-
ings to date suggest that for our tests in the near future
(the summer of 1990), the most effective mixture of
materials is a paste containing table sugar, Lannate
technical powder, and a polymer thickener as a resi-
due-extending agent. Present data suggest that we
would need to re- treat spheres with this mixture every
3 weeks to maintain high effectiveness. Hopefully, an
equally or more effective but safer pesticide than Lan-
nate and a more effective residue-extending agent may
be on the horizon.
We realize that a large number of pesticide- treated
red spheres on perimeter apple trees may invite pas-
sers-by to "pick" and handle these curious "apples."
We are experimenting with methods that would pre-
vent human fingers from touching the sphere surface
but would not affect AMF access to the sphere surface.
Acknowledgements
We thank the Northeast Regional Project on Inte-
grated Management of Apple Pests (NE-156), Massa-
chusetts Agricultural Experiment Station Project 604,
and DuPont Corporation for supplying materials for
this work.
20
Fruit Notes, Spring, 1990
Evaluation of Safer's™ Insecticidal Soap as
a Management Tool in Apple Orchards
Craig Hollingsworth and William Coli
Departments of Entomology, University of Massachusetts
Joseph Sincuk
Department of Plant & Soil Sciences, University of Massachusetts
While second-stage apple IPM is directed toward
eliminating chemical interference with the apple eco-
system, remedial pesticides are still required to correct
some orchard problems. Ideally, these pesticides
should have as little negative environmental impact as
possible. Further, as a defense against pesticide resis-
tance, it is also desirable to have available a range of
pesticides which use different modes of action. These
properties have been ascribed to insecticidal soap.
This study was established to compare Safer's™
Insecticidal Soap with standard orchard pesticides
under commercial apple growing conditions. Materials
were tested against common apple foliage pests, spirea
aphid, Aphis spiraecola (Patch), and European red
mite (ERM), Panonychus ulmi (Koch). In addition, the
effects of these materials on the aphid predators,
Aphidoletes aphidimyza Rondani (Diptera:
Cecidomyiidae) and Syrphus spp± (Diptera: Syrphidae)
were examined.
Methods Used
The study was conducted at the University of
Massachusetts Horticultural Research Center in Bel-
chertown, MA on two apple cultivars, Mcintosh and
Delicious. Four treatments were arranged in a ran-
1.0
8 0-8-
.E o.7 --
tn
§2 0.6-
o
■2 0.5-
1 0.4--
o
■-£ 0.3-
o
Q-0 2--
o V - J -^-
£ 0.1 --
0.0-
Spirea aphid
EZH Thioda
F553 Thioda
■■ Soap
i Z i Soap
n (/full rate)
n (half re
(full rate)
(half
rate) plus Soap (full rate)
rate)
>
a
</
5'
a
^
26 Jun 29 Jun 6 Jul
Mcintosh
26 Jun 29 Jun 6 Ju
Red Delicious
Figure 1. Proportion of leaves infested with spirea aphid. Treatments were applied on June 27. There were
no differences among means for each date and cultivar.
Fruit Notes, Spring, 1990
21
domized complete block design, replicated three times
and duplicated for each cultivar. Plots consisted of
three adjacent trees, with data taken from the center
tree. Trees, on M.7 rootstocks, were spaced 16 ftX 23 ft
and were 12 ft tall.
Four treatments were tested: (Da standard IPM
chemical regimen; (2) one-half rate of all chemicals
applied in treatment 1, supplemented with Safer's
Insecticidal Soap at the recommended rate (two gallons
per 100 gallons water) (fungicides were increased to
standard rates after July 6); (3) Safer's Insecticidal
Soap at the recommended rate, plus standard fungi-
cides; and (4) Safer's Insecticidal Soap applied at one-
half the recommended rate, plus standard fungicides.
Treatments were applied to run-off with a Bean
hydraulic handgun sprayer at 200 p.s.i., with a delivery
rate of 300 to 350 gal/acre. Dormant oil was applied to
all plots on April 27. Fungicides (Manzate™ 200DF
and Rubigan™ 12.5% EC) were applied on May 3, 12,
and 22. Rubigan was applied alone on June 4, and
Polyram™ 80% WP was applied on June 27, July 19,
and August 7. At petal fall (May 22), Guthion 50W
(standard rate: 5/8 lb/ 100 gal) and Safer's Insecticidal
Soap were applied in the appropriate plots as described
above. Aphid control treatments were applied on June
27 (standard: Thiodan™ 50WP at 0.5 lb/100; note that
this rate is one-half the recommended rate given in the
New England Apple Spray Guide, 1990). Mite control
treatments were applied on July 19 and 31 (standard:
Omite™ 30WP at 1.5 lb/ 100), and on August 7 and 14
(standard: Omite 30WPat2 lb/100). Treatments 3 and
4 received only soap, as described above.
Aphids and predaceous larvae were assessed by
determining their presence or absence from 15 termi-
nal leaves sampled from the central tree in each plot.
ERM were assessed by determining their presence or
absence on 15 spur leaves from the central tree in each
plot.
Phytotoxicity to foliage was evaluated by rating
leaf yellowing and leaf drop from the central tree in
each plotfrom (none) to 4 (severe). Harvest data were
collected by examining 100 fruit on the central tree in
each plot for any insect, disease, or phytotoxic damage;
one-third of the fruit was selected from the inside,
outside and top of the canopy. Mcintosh were evaluated
on September 6 and Delicious, on October 5.
Results
Aphids. Specimens submitted for identification
were all identified as Aphis spireacola, a difference
from samples in previous years, when Aphis pomi had
been the dominant aphid species.
Proportions of leaves infested with spirea aphid
were not significantly different among treatments in
pre- or post-treatment counts (Figure 1), due at least in
part to high variation within treatments. Thiodan
applications tended to be more effective in reducing
aphid infestations than were Safer's Insecticidal Soap
applications. Aphid infestations were not significantly
different between cultivars.
Aphid predators Thiodan applications, even at
low rates, reduced aphid predator populations signifi-
cantly more than insecticidal soap applications.
Syrphid presence was reduced following all treatments
(Figure 2). Ten days after treatment, there were sig-
nificantly more leaves infested with syrphids in the
block treated with the low rate of insecticidal soap than
in the other blocks. This result is consistent with other
work, which indicates that soap has no residual effect.
On June 29, all cecidomyiid larvae were eliminated
from all Thiodan-treated trees (Figure 3).
Cecidomyiids were reduced in all other treatments as
well. However, there were no significant differences
among treatments, again, probably due to sampling
variation.
Mites. Delicious trees had significantly more mite-
infested leaves than did Mcintosh trees on the first
three dates. Within cultivars, mite populations were
not significantly different among treatments, except on
July 24, when treatment 1 of Mcintosh had the most-
mites, treatments 2 and 3 the least, and treatment 4
was intermediate (Figure 4). While not statistically sig-
nificant, similar results were obtained in the Delicious
block; insecticidal soap applications resulted in lower
mite densities than applications of Omite alone, and
the full rate application of insecticidal soap produced
promising results with respect to mite control. How-
ever, control of mites in all treatments was inadequate.
The length of time between the first two applications
(12 days) was too long. The time period between the
second split application (7 days) was probably ade-
quate, but five inches of rain fell preceding the August
17count and few mites survived, eliminating mite con-
trol treatment effects. Thus, the most revealing infor-
mation on miticide activity was obtained on July 24.
Phytotoxicity and fruit damage Evidence of leaf
phytotoxicity was most severe on Delicious apples re-
ceiving a full rate of Safer's Insecticidal Soap (Figure 5).
Many leaves on this cultivar turned yellow and
dropped following the first soap application. Mcintosh
foliage did not exhibit leaf yellowing or drop. At har-
vest, direct fruit injury due to fruit damaging insects
and disease was within acceptable ranges (Figure 6).
No significant difference in insect injury to fruit was
found among treatments. Delicious apples receiving
Safer's Insecticidal Soap plus standard pesticides had
greater scab injury than the low rate of soap alone; this
22
Fruit Notes, Spring, 1990
0.5
<D
CO
CD
0.4--
co
§2 0.3
□
CU
~ 0.2
o
o
§-0.1
0.0
Aphid predators: Syrphus spp.
IZZI Thiod
^^3 Thiod
an (full rate)
an (half
Soap (full rate)
I / J Soap (half rate)
rate) plus Soap (full rate)
■g.
a"
o
a a a b
n b ■
26 Jun 29 Jun 6 Ju
Mcintosh
-o
a
5"
a a a b
26 Jun 29 Jun 6 Ju
Red Delicious
Figure 2. Proportion of leaves infested with syrphid larvae. Aphicides were applied on June 27. Means
within date and cultivar were not significantly different unless noted; where noted, means labelled by dif-
ferent letters are significantly different at odds of 19 to 1.
f~\ cz
Aph'
d
P
>redators:
Aphidoletes
aph
idimyza
u.o -
I I
Thiodan (full rate)
CD
■ ^3 Thiodan (half rate) plus Soap (full rate)
S 0-4-
■■ Soap (full rate)
\/ J Snap (half rote)
c=
CO
$ 0.3-
o
_cd
-a
:>
° 0.2-
T3
T3
o
a
n'
o
{21
!-•-
"-e
o
3
o
3
o
8-0.1 -
4
4
L_
Q_
n n .
—
I
In
I
26 Jun 29 Jun 6 Jul
Mcintosh
26 Jun 29 Jun 6 Jul
Red Delicious
Figure 3. Proportion of leaves infested with Aphidoletes aphidimyza. Aphicides were applied on June 27.
There were no differences among means for each date and cultivar.
Fruit Notes, Spring, 1990
23
TO
CD
C/J
CD
CO
CD
O
CD
o
1 .O
European red mite czd Omite (full rate)
KXl Omlte (half rate) plus Soap (full rate)
■■I Soap (full rate)
Soap (half rate)
0.9 --
0.8 '•'-
0.7 --
0.6--
0.5--
0.4---
O.J3 --
o
"t:
o
°r 0.2 4-
0.1 --
O.O
c a a b
-8-
a
-g--g--e-
"O
"D
■o
o
r>
o
a
o
a
o
o
o
3
=3
^
^
>!r
^
-o -o -&
-a -a -o
a a
o o o
3 3 3
18 Jul 24- Jul 30 Jul
Mcintosh
17 Aug 18 Jul 24 Jul 30 Jul 1 7 Aug
Red Delicious
Figure 4. Proportion of leaves infested with European red mite. Miticides were applied on July 19 and 31,
and August 7 and 14 August. Means within date and cultivar were not significantly different unless noted;
where noted, means labelled by different letters are significantly different at odds of 19 to 1.
Foliage phytotoxicity
I l
CD
CD
KXX
>
CD
■■
1
3-
1 / J
■*"
O
■*->
CD
C
o
c
1
2-
o
CT>
c
*-l
o
CD
1 -
CJ»
o
E
o
Q
standard chemical
wxn chemical (half— rate) plus soap (full rate)
soap (full rate)
(half
soap
rate)
Mcintosh
(no phytoxicity)
n
Red Delicious
Figure 5. Foliage phytotoxicity of apples under different insecticide regimens. Phytotoxicity is rated from
(none) to 4 (severe).
24
Fruit Notes, Spring, 1990
CD
en
o
E
o
-a
c=
a>
o
k_
Q_
cn
Fruit
c
amage
□ u
50 :
standard chemical
chemical (half — rate) plus soap (full
soap (full rate)
soap (half rate)
rate)
i y j
40-
30-
20-
10-
n .
•
n Ll
n . 1
Mcintosh Red Del.
Russetting
Mcintosh Red Del.
Insect Damage
Figure 6. Percent damage to fruit, assessed at harvest. Insect damage includes that from leafrollers,
tarnished plant bug, and codling moth. Means within cultivar were not significantly different unless noted;
where noted, means labelled by different letters are significantly different at odds of 19 to 1.
result cannot be explained biologically. Other treat-
ments did not differ with respect to scab injury.
Evidence of phytoxicity was present on fruit from
all Safer's-treated blocks (Figure 6) in the form of
russet-colored rings, a spray-burn. Rings generally
formed on the calyx end of Delicious and the shoulder
of Mcintosh. On Delicious apples, russetting was
greatest where higher rates of soap were applied, while
on Mcintosh, russetting was not related to rates of ap-
plication.
Conclusions
This study demonstrates that Safer's Insecticidal
Soap is an effective miticide when compared to Omite.
In our tests, soap was not as effective as Thiodan
against aphid populations. Aphid populations treated
with soap were not sufficiently reduced and they re-
bounded much faster than did those treated with
Thiodan. There was little difference among treatments
with respect to their effects on aphid predator densi-
ties, although the low rate of insecticidal soap appeared
to be less toxic on syrphid larvae.
An important concern in the use of insecticidal
soap is the severity foliar phytotoxicity exhibited by
Delicious, and the spray burn russetting on fruit that
occurred on both cultivars in our trials. This fruit dam-
age is apparently only cosmetic, but under current
grading standards it would result in a reduction of
value of the crop. Before insecticidal soap becomes a
useful apple orchard tool, it will be necessary to deter-
mine on which cultivars soap is phytotoxic, and under
what conditions such injury can be avoided.
*t* t&m t&m «f* aj#
♦J* •*£» *J* *J* *J*
Fruit Notes, Spring, 1990
25
Insecticidal Soap for Pear Psylla
Management
William M. Coli and Craig S. Hollingsworth
Department of Entomology, University of Massachusetts
Anthony Rossi
Department of Plant & Soil Sciences, University of Massachusetts
We reported in an earlier article [Fruit Notes
53(2): 13- 15] on a comparison between Safer's™ insec-
ticidal soap and amitraz applied by hydraulic handgun
as summer sprays against pear psylla. Results of that
study indicated that: 1) both the soap and amitraz
caused a significant reduction in active stages of psylla;
2) soap caused the formation of dark surface lesions on
49% of the pears; and 3) soap treatments were 37%
more costly than amitraz. However, these initial re-
sults were sufficiently promising, especially consider-
ing the desirability of developing alternate strategies
for psylla management, that we continued our investi-
gations of insecticidal soap as a tool for managing pear
psylla and various apple pests. In this article we report
on the results of our 1989 trials in pear.
Treatments were applied to two rows of 15 Bartlett
trees at the Horticultural Research Center (HRC),
Belchertown, MA. To more closely approximate the
application conditions in commercial orchards, all
chemical applications were made to run-off with a
Bean 400-gal speed sprayer at 300 psi with a delivery
rate of 50 gal./acre.
In both rows, oil at 1 gal/ 1 00 gals water was applied
on April Hand 25. Polyram™80 WPat 1 to 1.51bs/100
gal was applied on April 14 and 25, May 23, June 5 and
27, July 17 and 24, and August 9. Guthion™ 35 WP at
0.63 lbs/100 gals was applied at petal fall (May 23).
In the standard program block, Imidan™ 50 WP at
D
C
E
CD
CL
CO
E
CO
Q_
CD
en
o
k_
CD
>
<
1 zu -
1 1 Amitraz
■I Safer's
100-
80-
60-
40-
E
•*-
o
to
C
<
I
E
V
*♦—
o
N
a
-t->
<
0)
H—
o
r w
N
O
i_
t->
E
<
1
E
0)
•4—
1 o
CO
1
V
\l
' V
^
*
20-
tI
1
n _
fi* *- ^_ - __ I
I fl J
1 ..
1 Al J
May23June1 7 14 21 29 July 6 12 18 24 31 Aug 7 14 21 24 25
Figure 1 . The average number of all pear psylla nymphs per terminal throughout the 1989 growing season.
26
Fruit Notes, Spring, 1990
1 lb/100 gal was applied on June 5 and 27 for plum
curculio control and Mitac™ 1.5 EC was applied at 1.5
pts/100 gal on July 17 and 24 and on August 9 for pear
psylla.
Safer Insecticide Concentrate at 2 gal/ 100 gal was
applied to the treatment block on May 20, July 24, and
August 9 and 22 for pear psylla. No untreated check
trees were included in this study as previous experi-
ence has shown that psylla will reach significant out-
break levels in this block in the absence of any summer
control sprays.
The clumped distribution of active stages of psylla
resulted in high statistical variability within treatment
blocks. This variability in turn contributed to lack of
statistically-significant differences between treat-
ments even when population trends appeared to differ,
e.g., on June 29 and July 29 (Figure 1).
Significantly greater numbers of late instar psylla
nymphs were noted in the soap block at petal fall. An
initial soap treatment on May 26 effectively reduced
psylla numbers to levels comparable to trees destined
to receive Mitac treatments.
Soap-treated trees again had significantly greater
psylla levels on July 18; however, Mitac was applied on
July 17, without a corresponding application of soap.
In spite of this, early instar psylla numbers in the soap
treatment exhibited a downward trend on July 24,
while similar stages in Mitac trees had rebounded to
their highest levels. Trees treated with soap had
significantly more early instar nymphs than Mitac-
treated trees on August 21, 12 days after an application
of Mitac. The fourth soap application on August 22,
with no corresponding Mitac spray, effectively reduced
psylla numbers through the rest of the season.
Early instar psylla numbers in Mitac treated trees
had reached outbreak levels again on August 25, when
pre- harvest considerations would allow no further use
ofamitraz. In an adjacent pear block at the HRC where
a similarly increasing psylla population was noted,
soap was used effectively during the pre- harvest period
to reduce psylla infestations below acceptable levels.
Perhaps due to this late psylla outbreak, noted
above, treatment blocks did not differ significantly with
regard to sooty mold on fruit at harvest (8.7% and
11.0% for Safer's- and Mitac-treated blocks, respec-
tively). However, 50% of soap-treated fruit, compared
to none of the Mitac-treated fruit, exhibited the dark
surface lesions (fruit phytotoxicity) which we observed
in our 1987 trials and which have been reported in the
Hudson Valley. We view such lesions as a major
drawback to the use of soap sprays, as they contribute
to fruit downgrading. We are presently unable to
provide any information regarding the precise condi-
tions which contribute to phytotoxicity, or the steps
which may be taken to alleviate it.
We conclude that if insecticidal soap is integrated
into a psylla control program sufficiently early, i.e. as
psylla numbers begin to reach outbreak levels, its use
represents an effective psylla management alternative
to other summer spray materials. In our trials, four
soap applications costing $41.41/acre provided control
of pear psylla equivalent to three applications of Mitac
costing $15. 75/acre. However, unless progress toward
reducing fruit phytotoxicity can be achieved, low yields
of blemish-free fruit may deter use of insecticidal soap
sprays by even those growers who might otherwise
accept its higher cost.
Acknowledgments
We wish to thank Safer, Inc., for donating the
material for our 1989 trials and Mary Ellen Ahearn for
technical assistance. This project was funded through
the Massachusetts Department of Food and Agricul-
ture Competitive Grant Program.
at* •£• «£• «J* *$+
•J« «j» *J» »J» wgm
Fruit Notes, Spring, 1990
27
Fruit Notes
University of Massachusetts
Department of Plant & Soil Sciences
205 Bowditch Hall
Amherst, MA 01003
Nonprofit Organization
U.S. Postage Paid
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Fruit Notes
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
ISSN 0427-6906
sc 1
Volume 55, Number 3
SUMMER ISSUE, 1990
Table of Contents
Where Do Apple Maggot Flies Find Food in Nature?
How Do Apple Maggot Flies Detect the Presence of Food?
How Do Apple Maggot Flies Search
For Food on Leaf Surfaces?
What Kinds of Food Do Apple Maggot Flies
Need for Survival and Reproduction?
How Often Do Apple Maggot Flies Need to Eat?
Apple Bruising V. Apple Bruising Related
to Picking and Hauling Practices
The Fifth International Controlled Atmosphere Research Conference
(- M Controlling Postharvest Diseases of Apples and Pears
Blueberry Culture
News from Other Areas
In Memorium: William T. Pearse, 1903-1990
iti^f^rv » Damage to Maturing Apples by Birds
\£.** Assessing Effects of Depredation by Deer on Apple Production
Fruit Notes
Publication Information:
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April, July, and October by the Department of Plant & Soil Sciences,
University of Massachusetts.
The costs of subscriptions to Fruit Notes are $5.00 for United States
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tion begins January 1 and ends December 31. Some back issues are
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dresses). Payments must be in United States currency and should be
made to the University of Massachusetts.
Correspondence should be sent to:
Fruit Notes
Department of Plant & Soil Sciences
205 Bowditch Hall
University of Massachusetts
Amherst, MA 01003
COOPERATIVE EXTENSION POLICY:
All chemical ases taggested ia this pablicatioa are coatiageal apoa coatUacd registratioa. These chemicals should be
aaed ia accordance with federal and •talc law* aad regulations. Groaien are arged to be familiar with all curreat stale
rcgalatioaa. Where trade aaaMa are aaed for idrarifiratioa, ao coaipaay endorsement or product discrim i nauoa ia
ia leaded. Ihe UaiversitycJ Massachusetts nukes aowarraaty or guarantee of any kind, expressed or implied,
concerning the a»e of these products USER ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY
DAMAGE.
hated by ike University of Uaisadiuxtis Cooperative Ettaaaiaa, Robert G. Hdgcsen, Director, in furtherance of the ads
of May 8 and June 30, 191 '4. The University afUa a a c ku Mi t i Cooperative E x mav i tm offen equal opportunity in p r v p am s
and employment.
Where Do Apple Maggot Flies Find Food in
Nature?
Jorge Hendrichs and Ronald Prokopy
Department of Entomology, University of Massachusetts
To manage insect pests effectively, we need to un-
derstand as much as possible about how they acquire
resources of food, mates, and egglaying sites. Over the
past decade or so, we have gained substantial insight
into how apple maggot flies search for mates and
egglaying sites. But until recently, neither we nor
anyone else has examined in a systematic fashion the
way the flies acquire food. In this article, we report on
the kinds of plants upon which apple maggot flies find
food in nature, and the types of food most frequently
eaten. In the 4 succeeding articles, we discuss how the
flies are able to detect the presence of food from a
distance, how flies search for food on leaf surfaces, the
kinds of food that support fly reproduction, and the
frequency with which the flies need to feed to attain the
greatest number of eggs. Information of this kind is
important not only in furthering our understanding of
fly behavior but also can be used in designing new
behavioral approaches to fly control.
Methods Used
In 1987, we conducted a quantitative assessment of
fly feeding activities in nature over time and space, and
identified feeding sites on host and non-host plants.
Observations were made in an abandoned apple or-
chard (mainly Early Mcintosh), in Amherst, Massa-
chusetts. Studies began in early summer when flies
first emerged from overwintering pupae, and contin-
ued through the entire period of a single fly generation,
for a total of over 300 observation hours. Flies were ob-
served systematically in three separate areas of the
orchard. Each of these areas included a fruiting apple
tree, a non-fruiting apple tree, and a transect through
the surrounding non-host vegetation. Equal observa-
tion time from 7AM to 6PM was allocated to each type
of tree and area.
Results
Results indicate that after fly emergence and for
approximately 7 days thereafter (corresponding to the
sexual maturation period), foraging for food is appar-
ently the predominant type of fly activity. At dawn, flies
of both sexes were at rest in upper, sunlit parts of tree
canopies. It was here that they began feeding. As the
temperature increased, they moved progressively to
lower, more shaded positions.
During the sexual maturation period (i.e., the first
week), flies were found mostly on non-fruiting host
trees and surrounding non-host vegetation. After this
first week period, fly presence shifted markedly to
fruiting host trees (Table 1), where matings and op-
positions take place on the fruit. The average number
of feeding events per observed fly decreased gradually
over time: 0. 16, 0. 14, 0. 12 and 0.12 for the first, second,
third, and fourth weeks of observation, respectively.
Each week, the percentage of flies observed feeding was
Table 1. Total numbers of adult apple maggot
flies observed over 4 weeks (early July to early
August) on fruiting apple trees and on other
vegetation (non-fruiting host trees and sur-
rounding non-host vegetation) in an abandoned
apple orchard.
Percent of
individuals present on
Total number Fruiting Other
Week observed host trees vegetation
1
751
40
60
2
764
62
38
3
826
68
32
greater on non-fruiting host trees and surrounding
vegetation than on fruiting host trees (Table 2).
Although as flies matured they spent increasing
amounts of time on host fruit for mating and oviposi-
tion, foliage remained the most common apple maggot
fly feeding site, followed by feeding on fruit surfaces or
wounds (Table 3). Flies spent considerable time mov-
ing from leaf to leaf, often dabbing their mouthparts on
apparently diffuse (i.e., non-observable) food resources
on upper leaf surfaces. The identity of these diffuse
resources remains to be determined (the fourth article
in this series gives further information on this subject).
Fruit Notes, Summer, 1990
Table 2. Apple maggot flies observed during 4
weeks feeding on fruiting apple trees and on non-
fruiting host trees and other vegetation in an
abandoned apple orchard.
Percent of
individuals feeding on
Fruiting Other
host trees vegetation
Number observed
Week feeding
1
2
3
4
120
110
103
77
29
45
34
42
71
55
66
58
Formerly it was thought that aphid or leafhopper ex-
crement (honeydew) on foliage was the principal food
of apple maggot flies in nature; however, we never de-
tected any droplets of honeydew on the plants observed
in this study area.
One of our most important findings was the obser-
vation of considerable fly feeding on bird droppings, a
probable source of nitrogenous compounds, which are
essential for egg development. Droppings were found
on a variety of fruiting plants, including apple trees.
Fruiting buckthorn (Rhamnus) was the main non-host
feeding site. Birds were attracted to buckthorn bushes
having ripe berries and favorable perching sites. Here,
it was common to see flies feeding on bird droppings,
dropped fruit pieces, and leaf surfaces. Competition
with other apple maggot flies and other types of flies for
these food sources on buckthorn was observed on sev-
Table 3. Plant structures and substrates on fruiting apple
trees, non-fruiting host trees and surrounding non-host
vegetation upon which apple maggot flies were observed to
feed over 4 weeks.
Substrate
Percent of flies feeding
on
Leaves
Fruit
Other
Total %
Undefined matter
on plant surfaces
Bird droppings
Fruit juice
Insect frass
Total %
68
10
2
80
9
1
5
1
16
2
1
1
4
79
12
8
1
100
era! occasions.
Later in 1987, additional observations were made
in a grove of wild hawthorn trees near Geneva, NY, and
on hawthorn trees on the campus of the University of
Massachusetts at Amherst. In the first case, the pat-
tern of findings was similar to the one described above
(i.e., the flies left fruiting host trees regularly in search
of food). In the second case, however, one of the fruiting
hawthorn trees had shiny leaves with plenty of aphid
honeydew. Here, flies were seen feeding on the honey-
dew, mating, and ovipositing. They appeared to con-
centrate more of their activites on this tree.
In general, we observed apple maggot flies spend-
ing considerable time in apparent indiscriminate for-
aging for diffuse food sources on leaf surfaces of host
and non-host trees. This "grazing" type of feeding may
be typical of apple maggot flies under conditions of
scarcity of honeydew or other carbohydrate and pro-
tein resources. Such adjustment in food foraging activ-
ity in response to dynamic changes in the spatial,
temporal, and seasonal distribution of food resources
(for example after rains), probably also bears upon the
variable effectiveness of such management tools as
food-baited monitoring traps and insecticidal-bait
sprays.
Our study has shown that in the absence of abun-
dant food resources on fruiting host trees, flies leave
hosts during the sexual maturation period. Even after
the onset of egglaying, females continue leaving food-
scarce hosts in the absence of nitrogenous food to
forage in the surroundings. Odor from highly concen-
trated food sources may direct this searching behavior
(the second article in this series gives further informa-
tion on this subject).
Implications for Orchard
Management
There are various ways that some of our
findings on apple maggot fly food foraging
may contribute to successful implementa-
tion of the second stage of the apple IPM
program. One is maintaining orchards pur-
posely scarce of natural food resources by
adjusting pruning practices to discourage
formation of fresh sprouts and attendant
buildup of aphids on the sprouts. Another is
discouraging flocks of birds from entering
orchards through use of Scare-Eye bal-
loons. Fewer birds would result in both
fewer wounded fruits and fewer bird drop-
pings as sources of food for adult flies.
In food-scarce orchards, immigrating
Fruit Notes, Summer, 1990
flies might inhabit largely the perimeter trees because
of their need to move back and forth to the surrounding
vegetation regularly to obtain food. This movement
could increase many-fold the probability of capturing
flies on odor-baited interception traps placed on pe-
rimeter trees before flies penetrated into the orchard
interior.
Finally, if orchards were consistently scarce in
natural fly food, the effectiveness of perimeter inter-
ception traps (currently baited with synthetic apple
odor) might be enhanced by the addition of synthetic
food odors.
Acknowledgements
We thank David Eagle and Maryam Masahayekhi
for their help during various aspects of these studies.
This work was supported by the Science and Education
Administration of the USDA under grant 8700564
from the Competitive Grants Office, and by the Massa-
chusetts Agricultural Experiment Station Project 604.
%f* *J* «J» *I* •&»
•J» »j» »J» »j» «^»
How Do Apple Maggot Flies Detect the
Presence of Distant Food?
Jorge Hendrichs, Martha Hendrichs, Joshua Prokopy, and Ronald
Prokopy
Department of Entomology, University of Massachusetts
Brian Fletcher
CSIRO, Canberra, Australia
Our field observations, described in the first article
in this series, showed that in the absence of abundant
food resources on fruiting host trees, apple maggot fly
females leave hosts (even after the onset of egglaying)
to forage in the surroundings. We hypothesized that
odors from concentrated or high quality food sources
may direct this searching behavior.
For years there has been no agreement on the
question of whether apple maggot flies respond to
commercial food baits as other fruit flies do, although it
is known that apple maggot flies do respond to ammo-
nia, a typical volatile product resulting from the bacte-
rial breakdown of food baits and other protein sources.
Based on these facts and our findings from the field, the
following 3 tests were carried out.
Effect of Age and Protein Deprivation
The objective in our first test was to determine the
effect of fly age and protein deprivation on the response
of apple maggot flies to ammonia volatiles. We released
flies of different feeding status, age, and sex in the
center of a patch of 25 potted, non-fruiting hawthorn
trees in an open field at the Horticultural Resesarch
Center, Belchertown, MA. At the outer edge of this
patch and at a distance of 4 meters from the release
point, we placed (in alternating positions) 8 sticky-
covered 250 ml plastic vials filled with either a 0.1
molar solution of ammonium bicarbonate or water
(vials were 3 meters from each other). Fly capture on
outer surfaces of the vials was measured 30 minutes, 2
hours, and 24 hours after each release. The containers
were rotated every trial.
Results in Table 1 show an important effect of
feeding status and sex, and to a smaller degree age, on
fly response to ammonia. Protein-deprived flies, at all
ages, were much more responsive to ammonia than
flies having fed recently on yeast. Under all situations,
females were much more responsive to ammonia than
males. Although protein-deprived females of all ages
responded to ammonia, the highest response occurred
in the latter part of the sexual maturation period (when
flies were 8 to 10 days old). Most of the fly captures
occurred in the first 30 minutes to 2 hours after release.
Fruit Notes, Summer, 1990
Table 1. Percent capture of released protein (yeast)- deprived
and non-deprived immature and mature apple maggot flies
that responded overa 4-meter intertree distance to a 0.1 Molar
solution of ammonium bicarbonate or water.
Females captured
Fly age (%)
Males captured
(%)
(days) Ammonia Water
Ammonia
Water
I. Continuous access to protein
3-6
8-10 7 3
16-18 3 7
3
3
3
3
10
II. Continuous deprivation of protein
3-6 28
8-10 60 3
16-18 37 7
5
30
III. Access to protein to day 10
12-13 3
16-18 23
3
3
3
Nearly all flies were caught on the ammonia source
that was upwind from the patch of hawthorn trees at
the time of testing.
Testing of Commercial Bait
In the second and third tests, our goal was to
determine the effectiveness of a commercial protein
commonly used in bait sprays, and to test the possibil-
ity of enhancing the attractiveness of such a commer-
cial product through increased release of ammonia.
This enhancement can be achieved either by raising
the pH, or through the addition of an ammonium com-
pound.
Both of these tests were carried out in large field
cages, in the center of which we placed a hawthorn tree
about 1.5 meters tall. At a distance of 1 meter from the
center of the hawthorn tree, we placed in each of the
cardinal directions an apple twig with 10 leaves, fas-
tened to a pole. The outer foliage of the hawthorn tree
and the apple twig were about 20 cm apart. A cotton
wick, dipped 2 to 6 hours earlier into one of the treat-
ment solutions, was attached with a wire to the stem of
the apple twig. Ten mature females, protein deprived
for 6 to 8 days, were released in each replicate. They
were observed over a period of 80 minutes (rotation of
wick positions every 20 minutes) to quantify the num-
ber of visits to the different wicks.
In the second test we compared wa-
ter, a 0.1 molar solution of ammonium bi-
carbonate, the commercial fruit fly food
attractant Nulure™ (PIB-7) at the recom-
mended rate for ground bait sprays (a 1%
solution), and a solution (at the above
rates) of the two latter treatments com-
bined. Results of this test (Table 2) con-
firmed the attractiveness of ammonia and
the fact that flies move mainly upwind to
the source of the attractant. Surprisingly,
results also indicated a relatively poor at-
traction to the commercial food bait.
In the third test we compared the
same treatments as in the second test,
except that for the ammonium bicarbon-
ate solution we substituted a 1% Nulure
solution in which we adjusted the pH
from 6.5 (that of the commercial product)
to 8.5. Results of this test (Table 2) again
showed that the addition of ammonium
bicarbonate increased substantially the
attractiveness of the commercial food bait
Nulure. However, the adjustment from a
slightly acidic pH to an alkaline pH of 8.5
did not increase, as expected, the attrac-
tiveness of Nulure.
Conclusions
The capture over 2 hours, at a distance of 4 meters,
of up to 60% of apple maggot fly females released in a
patch of hawthorn trees in the first experiment indi-
cates the strength of ammonia as a food-type attrac-
tant. The response to ammonia was largely influenced
by fly feeding status. Although flies do not feed on
ammonium compounds, ammonia produced by bacte-
rial breakdown of amino acids apparently serves as an
indicator to protein-starved flies that proteinaceous
food is present in the immediate surroundings. Since
these foods can be found in insect honeydew, flies
probably can detect these substrates in part through
the odor of ammonia released by them.
In a food-rich natural environment, food-baited
traps for apple maggot flies must compete with natural
substrates. On the other hand, in orchards maintained
in a way that natural fly food is scarce (see the first
article in this series), the addition of a synthetic food
odor such as ammonium bicarbonate might increase
the attractiveness of certain fly traps, including pe-
rimeter interception traps. In such food-scarce or-
chards, it is possible that not only would mature fe-
males be retained by interception traps in perimeter
trees, but also that during their daily foraging for pro-
Fruit Notes, Summer, 1990
Table 2. Numbers of appl
e maggot fly visits to cotton wicks im-
pregnated with different solutions placed 1 meter from the
point at which flies were
released at the center of a hawthorn
tree. Some flies made repeat visits to wicks.
Treatment
Total number of fly visits to wicks
North
East
South
West
Total
TESTD
Water
2
1
3
Nulure
1
2
2
2
7
Ammonium
bicarbonate
1
5
6
2
14
Ammonium
bicarbonate
+ Nulure
2
7
7
16
Total
4
16
15
5
40
TEST III
Water
4
7
1
3
15
Nulure
(pH 6.5)
2
2
9
5
18
Nulure
(pH 8.5)
2
5
8
4
19
Ammonium
bicarbonate
+ Nulure
22
24
7
7
60
Total
30
38
25
19
112
teinaceous foods, females would respond
sooner to ammonium-baited intercep-
tion traps than females exposed only to
non-ammonium fruit-odor baited traps.
As a result, although fly capture might
eventually be the same on both types of
traps, egg-laying in fruit before capture
might be different.
The relative attractiveness of natu-
ral food sources remains to be tested, as
does the attractiveness of commercial
food baits other than Nulure. We hope to
find commercial bait that is specifically
attractive to apple maggot flies. An im-
portant aspect to be evaluated is that
ammonium or other food-type attrac-
tants as complements to fruit-odor
baited red sphere interception traps do
not affect adversely the beneficial fauna
in an apple orchard.
Acknowledgements
We thank Maryam Mashayekhi and
Jung Tang Wang for their help during
various aspects of these studies. We also
thank Martin Aluja for encouraging us
to use his patch of potted hawthorn
trees. This work was supported by the
Science and Education Administration
of the USDA under grant 8700564 from
the Competitive Grants Office, and by
the Massachusetts Agricultural Experi-
ment Station Project 604.
Fruit Notes, Summer, 1990
How Do Apple Maggot Flies Search for
Food on Leaf Surfaces?
Jorge Hendrichs, Joshua Prokopy, and Ronald Prokopy
Department of Entomology, University of Massachusetts
Brian Fletcher
CSIRO, Canberra, Australia
Our field observations (first article in this series)
showed that apple maggot flies spend considerable
time foraging for diffuse food sources on leaf surfaces of
host and non-host trees. We concluded that this "graz-
ing" type of feeding may be typical of flies when concen-
trated food sources that are presumably detectable by
odor from a distance (see second article in this series)
are scarce or lacking.
How do flies find diffuse food sources on leaf sur-
faces that are not readily detectable by odor? Field
observations indicated that the searching behavior for
food on foliage occurs during stereotyped hopping from
leaf to leaf: a fly walks diagonally across the top of a leaf
in an approximate straight line, jumps to the under
side of a leaf above it, moves to the upper side of that leaf
and walks again across the leaf surface, before hopping
once more to another leaf above it. Occasionally, the fly
lowers its mouthparts (proboscis) on an upper leaf
surface, probably in response to a food substrate de-
tected initially with the tarsi (terminal extensions of
the legs). Depending apparently on food quantity and
quality as perceived during touching of the proboscis,
the fly is either (a) arrested and feeds at length, (b)
stimulated to probe and feed periodically while con-
tinuing to walk slowly, or (c) not stimulated to probe or
feed, but rather it continues walking without altering
its approximately straight-line course across the leaf
surface. In the first 2 cases, after feeding or while
feeding-walking, the fly switches from a rather unidi-
rectional walk to a convoluted searching pattern of
walking and turning. If, during this localized search,
the fly detects more food it again undertakes area-con-
centrated search on the leaf. The following experi-
ments addressed the effect of food quality and quantity
on fly foraging and feeding behavior on leaf surfaces.
Methods Used
Tests were carried out in field cages in Amherst,
MA, in the summer of 1988. Apple twigs with ten leaves
each were used for the foraging studies. Before mount-
ing twigs on their poles about 1 m tall, twigs were
washed thoroughly with detergent and handled with
gloves. This procedure was necessary to remove any
trace of existing food and to insure that flies had access
only to food deposited (i.e., yeast or sucrose) as a droplet
on the upper surface of the leaf upon which they were
released. For each trial a "new release leaf ' was pinned
to the twig and a droplet of a food solution placed on it.
Leaves with dry food were prepared in advance to allow
the droplet to dry. The position of the release leaf was
always between the second and third lowermost leaves
of the twig.
We worked with apple maggot females of wild
origin (5 to 7 days old), thatwere maintained in labora-
tory cages and were deprived of protein from emer-
gence. They had access only to sucrose and water. In
trials where we tested fly reaction to sucrose, flies were
deprived of sucrose 12 to 18 hours before testing. For
each trial, a single fly was placed on the release leaf near
the food droplet. The fly was transferred to the release
leaf on a piece of filter paper dipped into a 0. 1% solution
of the food resource on the release leaf. Observations
commenced the moment the fly found the food drop,
and lasted until the fly left the twig or if it did not leave,
for a maximum observation period of 30 minutes. Each
treatment was replicated 30 times.
Fly Foraging, Food Concentration,
and Acceptance Thresholds
A series of foraging tests was conducted, both with
yeast hydrolysate and with sucrose, in which we varied
either the concentration of food per droplet, the
amount of food solutes, or the total droplet volume. In
the first test, we report those findings that illustrate
the effect of food concentration and quantity on fly for-
aging behavior. Flies were presented with a constant
droplet size of decreasing amount of food and hence of
decreasing nutritional value.
As shown in Table 1, for both yeast and sucrose, fly
foraging time on apple twigs as well as the number of
Fruit Notes, Summer, 1990
Table 1.
Effect of quality of food (
i.e., yeast
or sucrose)
in droplet
size of constant volume and decreasing concentration
on subse-
quentfood foraging behavior of apple maggot flies onfoliated apple
twigs.
Flies
eating
Average
Average
Amount Concen-
entire
foraging
number
Droplet
of tration
droplet
time on
of leaves
size
food (%)
(%)
twig (min)
visited
A. YEAST
0.5 fi\
125.00 fig 30.00
100
8.0
19.6
0.5^1
12.50 fig 3.00
97
5.9
14.4
0.5 ftl
1.25 fig 0.30
57
3.9
6.9
0.5 //l
0.12 ng 0.03
3
2.7
5.9
0.5/il
0.00 fig 0.00
2.3
4.9
O.Ofil
0.00 fig 0.00
—
2.4
5.6
B. SUCROSE
0.5 //l
130.00 fig 30.00
77
4.7
9.1
0.5^1
13.00/^g 3.00
30
2.3
4.6
0.5/^1
1.30 fig 0.30
10
1.2
3.3
0.0 fi\
0.00 fig 0.00
—
1.3
3.2
leaves visited after consuming a droplet decreased with
decreasing food concentration. Evidently a fly
"sensed" it was not worth the effort to spend a lot of
time looking for food when the most recent information
available to it indicated the food in the immediate
vicinity was likely to be of low quality, that is of low con-
centration per volume ingested. The results also indi-
cate thresholds of food concentration below which flies
were not stimulated to probe the leaf surface with the
proboscis to feed. Most flies accepted yeast at a concen-
tration about 10 times lower than they accepted su-
crose. Food acceptance thresholds can vary many-fold
depending on the general state of fly nutrition. Obvi-
ously, the limits of acceptance obtained correspond to
those of hungry immature flies.
Detection and Ingestion Thresholds
In our second test we used dry food and asked, what
are the smallest food quantities on a leaf surface a
hungry fly can detect? At the same time we asked, what
are the upper thresholds of food quantity that inhibit
further fly appetite and further food foraging behavior?
We found that protein-deprived apple maggot flies
would regularly detect and ingest the smallest amount
of dry yeast treatment we offered (6^g, which is some-
what less than about one thousandth
of the weight of an average fly). They
responded, provided that they walked
directly over the food so that their
tarsi came into contact with it. These
results confirm our observations
from nature (see first article in this
series) and from our tests using pot-
ted trees in field cages (see fourth
article in this series) that flies feed on
very small dry particles on leaf sur-
faces. They also indicate that in fu-
ture tests, we would need to present
flies with far smaller quantities of
food than we did here if we want to
approximate the true threshold of dry
food ingestion by hungry flies. We
find it remarkable that flies can detect
and eat such tiny particles of food,
which in future studies could possibly
turn out to be about equivalent to a
hungiy human feeding on grains of
rice one at a time.
In relation to the largest amount
of food a fly can ingest in a meal, our
findingswere more definitive. Of flies
presented with concentrated dry
yeast particles of 0.25 mg, 83% were
able to consume them in a single meal lasting an aver-
age of 7.5 minutes. About 57% of flies consumed par-
ticles twice as large (0.5 mg), with the average feeding
time 11.9 minutes. Finally, only 20% of flies were able
to consume food particles of 1.0 mg, with an average
feeding time of 21.7 minutes. This would be about
equivalent to a human eating a meal of one sixth of his
weight. For liquid food, the amount that roughly 50% of
flies could injest was slightly higher (about 0.8 mg)
than in the case of dry food. Overall, flies could ingest
liquid food faster than dry food. Variation in fly size was
probably responsible for some of the differences ob-
served between flies. But the results show that like
Americans at Thanksgiving dinner, a fly can stuff itself
only so much (equal to about a 30 pound turkey, with
all the trimmings) before it is time to quit eating.
Regurgitation Behavior
We found that flies drinking a liquid food solution
were generally still hungry, even though fully en-
gorged. These flies regurgitated droplets of liquid food
and held them externally on their mouthparts for
varying periods of time after which they ingested again
some liquid food and regurgitated droplets once more.
We hypothesized that during this regurgitation or
Fruit Notes, Summer, 1990
"bubbling" behavior a fly con-
centrates liquid foods, through
evaporation.
In our third test, we looked
closer at fly regurgitation or
"bubbling" behavior. We pre-
dicted that flies would increase
this behavior with decreasing
concentration of food encoun-
tered. We therefore presented
flies with a constant quantity of
food diluted in droplet size of
increasing volume (decreasing
concentration). Results from us-
ing both yeast (Table 2) or su-
crose solutions confirmed our
prediction. Indeed, through
"bubbling", hungry flies appear
to eliminate excess water from
the body to make space available
for more food. Longer total rest-
ing times between the various meals corresponded to
increasing volume sizes of food droplets ingested. Flies
apparently evaporated through "bubbling" sufficient
water to enable them to ingest progressively, in various
small meals separated by "bubbling" periods, up to 8
ftp of diluted food. We found that this behavior oc-
curred not only in females, but also in males. Although
"bubbling" was observed over a broad range of tem-
peratures, it occurred more readily under higher tem-
peratures and could possibly, therefore, also fulfill a
role as a cooling mechanism for flies under warm
weather conditions. (What an "inventive" way to deal
with a hot July day!) On occasion, flies also regurgi-
tated "bubbles" onto the leaf surfaces and reingested
the remaining dry solids once the drops had dried out.
Food Size and Finding Time
In a final experiment, we tested whether flies can
find larger droplets of food easier than smaller
droplets. For this test, food droplets (yeast)
were not placed on the release leaf, but one on
each of the second and third uppermost leaves
of the twig. A fly was observed until it found a
droplet, left the twig, or 30 minutes had
elapsed.
Results in Table 3 indicate that while more
flies did find larger food droplets, the average
time these flies took to discover larger droplets
was not different from flies discovering smaller
droplets. This outcome was to be expected
based on the stereotyped search behavior of
apple maggot flies we have observed on foliage:
Table 2. Effects of form of presentation
of a constant
quantity of protein
(yeast), presented in droplet
size of increasing volume and therefore
decreasing concentration, on
feeding and resting time of appl
e maggot
flies.
Flies
eating
Amount Concen-
entire
Average time (min)
Flies
Droplet
of tration
droplet
bubbling
size
food (%)
(%)
Feeding
Resting
(%)
0.15/vl
125/^g 100.0
97
2.7
2.6
3
0.5^1
125/ig 30.0
100
0.7
4.8
20
1.0^1
125//g 15.0
97
0.9
13.9
83
2.0/^1
125^g 7.5
93
1.5
20.6
9
4.0 n\
125//g 3.8
83
2.7
19.9
100
8.0 /;1
125/<g 3.1
67
2.9
19.5
100
0.0/il
O.Ofig 0.0
0.0
1.4
for both sizes of droplets flies took a similar time
hopping upward from leaf to leaf until reaching the
leaves with the droplets. Once there, and walking
across the upper leaf surface, flies were more prone to
miss smaller droplets, and came more readily into
contact with larger droplets. As we would have pre-
dicted for such small food droplets of such a low food
quality (low yeast concentration), odor apparently did
not play a role in droplet discovery.
Conclusions
We found that the quantity and quality of food en-
countered on a leaf surface determines subsequent
foraging time of apple maggot flies on the immediate
surrounding foliage. Also, the form of the food encoun-
tered affects, through the food "handling" or "process-
ing" time (feeding and resting), subsequent time avail-
able to flies for further foraging or other activates. Dry
Table 3. Effect of droplet size of constant concentration of
protein (1% yeast), on apple maggot fly discovery or
leaving time on apple twigs.
Droplet
size
Discovering
food droplet
(%)
Average time
to discover
food (min.)
Average time*
to leave twig
(min.)
0.0^1
1.0^1
10.0/<1
30
52
6.4
6.5
9.7
9.5
8.2
Includes only flies not discovering a food droplet.
8
Fruit Notes, Summer, 1990
food and slightly diluted food require about the same
"handling time": food in dry form takes the longest to
ingest, but requires only a relatively brief resting pe-
riod for cleaning, and no time for "bubbling". Slightly
diluted food is ingested faster but requires more resting
time afterwards to process the food through "bub-
bling". Very diluted food requires the longest "han-
dling time": it is consumed the fastest, but flies must
interrupt feeding by increasingly longer bubbling peri-
ods to be able to continue ingesting liquid food.
These findings are not only of academic interest.
Efforts are underway to substitute the sticky material
on host-odor baited red sphere interception traps with
a more practical alternative (Fruit Notes 54:18-19).
Insights gained from this study will be useful in the
development of such a substitute, which most likely
will be a slow-release feeding stimulant combined with
a toxicant. To be effective, the food type and quantity
covering a red sphere should not only arrest and stimu-
late the feeding of flies landing on a sphere, but also the
form of presentation of food should maximize the food
"handling" time. By so doing, flies would be exposed
for a sufficiently long period (through contact or inges-
tion) to the food-toxicant mixture. As a result, they
would die sooner and no longer be able to continue egg-
laying in that orchard.
Acknowledgements
We thank Jung Tang Wang for his help during
various aspects of these studies. This work was sup-
ported by the Science and Education Administration of
the USDA under grant 8700564 from the Competitive
Grants Office, and by the Massachusetts Agricultural
Experiment Station Project 604.
•£» •!» »l* *J> »3*
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What Kinds of Food Do Apple Maggot Flies
Need for Survival and Reproduction?
Jorge Hendrichs, Sylvia Cooley, and Ronald Prokopy
Department of Entomology, University of Massachusetts
Carol Lauzon
Department of Entomology, University of Vermont
In a field study (first article in this series), we iden-
tified various sites where apple maggot flies were ob-
served feeding in nature. Since then, we have collected
naturally occurring potential food sources at these sites
and assessed their contribution to apple maggot fly sur-
vival and egglaying. Here, we report results of these as-
sessments obtained both in the laboratory and on host
trees in large field cages.
Laboratory Tests
First, we carried out laboratory tests in which we
compared the standard laboratory food (yeast hydroly-
sate and sucrose) with potential food substrates col-
lected in nature. These included: bird droppings, insect
frass, apple leaves (small branches placed in a nutritive
solution), fruit surfaces, and combinations of these. We
knew that flies need carbohydrate for survival and pro-
tein for egg production (see the fifth article in this se-
ries). Therefore, to determine the nutritive nature of
the field collected materials, these were presented to
flies both with and without sucrose as carbohydrate.
Flies were provided with hawthorn fruit or artificial
fruit as egglaying sites.
Most flies, when provided with sucrose only and
artificial fruit as egglaying sites, were unable to pro-
duce eggs (Table 1). However, when the same sucrose
only treatment was provided with hawthorn fruit,
females consistently laid eggs, although well below the
egglaying obtained from yeast plus sucrose. Flies pro-
vided with only water (no sucrose) and hawthorn fruit
had a high mortality rate and no egglaying. We con-
cluded that flies were not able to obtain much carbohy-
drates, but possibly some proteins, from hawthorn
fruit.
With artificial fruit as egglaying sites, only combina-
Fruit Notes, Summer, 1990
Table 1. Fly survival and numbers of eggs laid
into hawthorn fruit or artificial fruit (i.e., wax
domes) by apple maggot flies confined to labora-
tory cages.
Survival at Eggs produced/
Treatment* 20 days (%) female/day
Yeast & sucrose
+ hawthorn fruit 86
Sucrose only
+ hawthorn fruit 80
Sucrose only
+ artificial fruit 80
No sucrose
+ hawthorn fruit
6.49
0.33
0.02
'For each treatment, 6 immature females and 3
immature males were released initially into each
of 6 laboratory cages (replicates). All treatments
had water.
"The last flies died after 5 days in the laboratory
cages.
tions that included bird droppings and sucrose, or
insect honeydew, yielded any appreciable egglaying.
This result occurred also when flies fed solely on apple
leaf surfaces. As the latter was one of the feeding sites
of flies in our field observations, we hypothesized that
high mortality and no egglaying was probably due to in-
sufficient quantity of foliage placed inside the small lab
cages, rather than to the quality of whatever food was
present on leaf surfaces.
Tests In Large Field Cages
We decided to extend the previous laboratory as-
sessment to large field cages (3 meters high x 3 meters
diameter). Each field cage was covered by a tarpaulin to
prevent rain washing away food resources (although at
the start of each test, trees were hosed down with
water). In each cage, we placed a potted apple tree and
a potted hawthorn tree. They were of similar size
(approximately 1 .5 to 2.0 meters tall). The foliage areas
available to the flies were estimated by counting leaves.
Three field tests were run, each with a different set of
apple and hawthorn trees.
For Field Test I, we used 4 field cages. In the first
cage we supplemented the flies' diet with sucrose and
yeast, in the second with sucrose and bird droppings, in
the third with sucrose only, and in the fourth with no
food. Flies were provided with hawthorn fruit as
egglaying sites. The results of this test (Table 2) con-
Table 2. Fly survival and numbers of eggs laid
into hawthorn fruit by apple maggot flies con-
fined to field-caged apple and hawthorn trees in
Field Test I.
Survival at Eggs produced/
Treatment* 20 days (%) female/ day
Yeast & sucrose 50
Bird droppings
& sucrose 70
Sucrose only 45
No sucrose
no change of trees
1.56
0.43
0.15
0.17
"For each treatment, 20 immature females and 5
immature males were released initially. All
treatments were provided with water.
"The last flies died after 15 days in the field cage.
firm the main findings of the lab tests. Again, bird drop-
pings in combination with sucrose yielded the greatest
amount of egglaying after the standard laboratory food
of yeast and sucrose. Interestingly, flies in the no-
sucrose treatment lived much longer than sucrose-
deprived flies in the laboratory tests. This result sug-
gests that flies find at least some carbohydrates on leaf
surfaces, although flies apparently used them up after
10 to 15 days of feeding. In both of these field cage
treatments, flies apparently obtained the proteins re-
quired to sustain a low level of egglaying from the
hawthorn fruit provided as egglaying sites.
For Field Tests II and III, 7 field cages were used.
The following three treatments were added to those of
Test I: aphid honeydew (excrement) and sucrose; a
preparation of some apple leaf bacteria and sucrose;
and a no-sucrose treatment wherein trees in the cage
were replaced renewed every 4 days. With the excep-
tion of honeydew and bird droppings, all food (includ-
ing sucrose), was presented in a diluted form. Daily,
cages were searched thoroughly for predators and dead
flies. Every second day, all flies were recaptured,
counted, and released again, and all food was renewed.
Results of Field Tests II and III (Table 3) were in
general very similar to those of Field Test I. Again, we
found no difference in survival between the sucrose-
only and no-sucrose treatments. Flies survived in these
treatments even longer than in field test I. These
results confirm once more that flies confined on caged
apple and hawthorn trees can apparently obtain suffi-
cient carbohydrates from leaf surfaces to satisfy some
basic energy requirements. This result may also ex-
10
Fruit Notes, Summer, 1990
Table 3. Average fly survival and average num-
bers of eggs laid into hawthorn fruit by apple
maggot flies confined to field-caged apple and
hawthorn trees in Field Tests II and HI.
Survival at Eggs produced/
Treatment' 20 days (%) female/day
Yeast & sucrose
Honeydew
& sucrose
Bird droppings
& sucrose
Leaf-bacteria"
& sucrose
Sucrose only
No sucrose &
no change of trees
No sucrose &
change of trees
every 4 days
88
63
65
73
68
53
63
1.79
1.14
0.81
0.43
0.42
0.44
0.28
'For each treatment, 20 immature females and 5
immature males were released initially. All
treatments were provided with water.
"Bacteria of the genera Bacillus, Enterobacter,
and Micrococcus.
plain why in nature males have to leave the fruiting
host trees considerably less often than females to for-
age elsewhere for food. It is known that males need
little protein in their diet. Additionally, males are less
mobile and of smaller size than females. Their energy
requirements are consequently smaller. Therefore,
males need to consume less carbohydrates, which they
seem to be able to obtain mostly from host tree foliage.
What is the origin of the carbohydrates that apple
maggot flies consume while feeding on leaf surfaces?
These may be minute residues of insect honeydews, or
plant fluids that regularly exude from leaf surfaces and
may contain carbohydrates.
Both honeydew and bird droppings yielded levels
of egglaying considerably greater than those of other
treatments, although still below the optimal laboratory
diet of yeast plus sucrose. In all other field cage treat-
ments, flies apparently obtained the proteins required
to sustain a low level of egglaying from the hawthorn
fruit provided as egglaying sites. Once more, there was
no difference in female egglaying between the no-
sucrose treatments and the sucrose-only treatment.
Also the supplement of apple leaf surface bacteria and
sucrose that we offered as a food source for flies did not
increase fly fecundity to any degree. This result is sup-
ported by a subsequent laboratory test with artificial
fruit, in which bacteria and sucrose yielded no eggs
whatsoever, similar to the result of the sucrose-only
laboratory treatment.
After the results of Field Test I, we predicted that
by regularly replacing the tree foliage in cages not sup-
plemented with sucrose or other food, flies would not so
rapidly run out of whatever food might be present on
the leaf surfaces. This was not the case. Although the
difference was slight, the no-sucrose treatment with
replacement of the foliage showed the lowest female
fecundity in both Field Tests II and III.
Another possible food source that we will consider
in future tests is bacteria of fly origin. Richard Drew in
Australia found that in a species of tropical fruit fly,
adults regurgitate fly-specific bacteria on fruit and
foliage. These bacteria then form colonies that spread
on plant surface nutrients, furnishing flies with pro-
tein of bacterial origin.
Conclusions
From these results, we can conclude that apple
maggot flies are able to gain at least some carbohy-
drates while "grazing" on leaf surfaces. As determined
from our field observations presented in the first article
in this series, flies actually do "graze" frequently on
leaf surfaces, though this feeding strategy appears to be
rather inefficient. Possibly, flies engage in this behav-
ior only in the absence of more readily available food
sources. Finding more concentrated sources of food,
such as insect honeydew and bird droppings, would
seem to be a much more efficient strategy. It would save
much time and energy, and gain appreciable time for
females to forage for fruit and to lay eggs. The fact that
we found females feeding at a distance from fruiting
host trees and a strong response of females to ammonia
odor (second article in this series) supports this inter-
pretation.
Acknowledgements
We thank Gabriela Gonzalez, Maryam
Mashayekhi, Patti Powers, Joshua Prokopy, Shifu Qu,
Barbara Richardson, and Jung Tang Wang for their
help during various aspects of these studies. Also we
wish to thank Richard Drew for encouraging this col-
laborative work, which was supported by the Science
and Education Administration of the USDA under
grant 8700564 from the Competitive Grants Office, and
by the Massachusetts Agricultural Experiment Station
Project 604.
Fruit Notes, Summer, 1990
11
How Often Do Apple Maggot Flies
Need to Eat?
Jorge Hendrichs, Sylvia Cooley, and Ronald Prokopy
Department of Entomology, University of Massachusetts
Our findings set forth in the first article in this
series revealed that adult apple maggot flies, whether
immature or sexually mature, may leave fruiting host
trees frequently in search of food on other nearby
vegetation. This finding implies that the flies may need
to eat rather often. In this article, we report some
results of laboratory tests aimed at determining just
how frequently apple maggot flies do in fact require
food to maintain a high rate of reproduction.
Unlike many other types of flies that lay large
batches of eggs in cycles, apple maggot females typi-
cally lay a few eggs every day, which necessitates a
regular supply of protein. Males, on the other hand,
have a very low (if any) protein requirement for repro-
duction. Both sexes need regular intake of water and
carbohydrates simply to survive.
Tests of Food and Water Deprivation
The first question we posed was: what are the nu-
tritious reserves that the flies carry with them at emer-
gence that allow them to survive until they come upon
their first food and water? To answer this question, we
carried out an experiment to observe the effect of size of
pupae and pupal reserves on fly longevity after emer-
gence. Each of 480 pupae, belonging to three selected
size categories, was weighed and kept individually.
Upon emergence, each fly was placed immediately into
one of four treatments: (a) no food, no water; (b) food
(yeast and sucrose), no water; (c) no food, water; and
(d) food, water.
Average longevity of flies was about 2 days when
they had no food and no water, 3 days when they had
food but no water, 4 days when they had no food but
water, and 50 days when they had both food and water.
Within each of the four treatments, survival decreased
with decreasing fly weight. Smaller females were more
affected than smaller males. Apple maggot flies are
nearly motionless during the first hours after emer-
gence, when their wings are hardening. During much
of the latter part of the deprivation period in our study,
they appeared too weak to forage and to evade preda-
tors. Therefore, the time during which emerging flies
are able to forage effectively for their first food and
water may be restricted to no more than a day or so.
Next, we deprived flies that previously had free
access to food and water for 8 to 16 days prior to depri-
vation. At the start of deprivation, the females had at
least a partially developed egg load, with some stored
food reserves in the crop. Even in this case, we found
that flies could survive without food only for a little
longer (for 3 to 5 days) than they could when they were
deprived immediately after emergence. Again flies
appeared too weak to forage effectively for food for
much of the last part of the deprivation period. Appar-
ently, food reserves stored in the crop and elsewhere
are exhausted rapidly, even when flies have had plenty
to eat for the preceding week or two.
Tests of Periodicity of Feeding
Given the above findings, we then asked what is
the importance of feeding during the one-week period
of fly maturation versus the importance of feeding after
the onset of egglaying? A laboratory test was carried
out to determine how critical the availability of protein
(in the form of yeast) was during these 2 different
Table 1 . Egglaying capability of apple maggot fly
females having free access, for varying periods of
time, to protein (in the form of enzymatic yeast
hydrolysate). Flies in all treatments were pro-
vided with a continuous supply of carbohydrate
(in the form of dry sucrose) and water. There
were 6 replicates (cages) per treatment, each
with 6 males and 6 females.
Days during life with
access to yeast
Lifetime number of eggs
laid per female per day
in artificial fruit
No days
Days 1 - 4
Days 4 - 8
Days 1-8
Days 8-11
Days 11-15
Days 1-42
0.04
0.44
0.66
0.60
0.22
0.42
2.61
12
Fruit Notes, Summer, 1990
periods.
The results (Table 1) showed that females that had
continuous access to sugar and yeast laid nearly 70
times as many eggs as adults that had continuous
access to sugar but no access to yeast, and 4 to 12 times
as many eggs as adults that had continuous access to
sugar but access to yeast only for a single 4- or 8-day pe-
riod. The results suggest that access to yeast might be
particularly important during the first week of life but
that even after reproductive maturity is attained by the
end of the first week or so, females still require frequent
protein intake to sustain high reproduction.
In our last test, we were interested in denning
more precisely just how much time can elapse between
protein meals before fly fecundity is affected. We al-
lowed flies free access to yeast either every day or every
second, fourth, eighth, or twelfth day.
The results (Table 2) show that females need to
ingest protein at least every fourth day to maintain full
egglaying capability. Successively fewer eggs per day
Table 2. Egglaying capability of females having
free access, at different intervals of time, to pro-
tein (in the form of enzymaticyeasthydrolysate).
Flies in all treatments were provided with a
continuous supply of carbohydrate (in the form
of sucrose) and water. There were 6 replicates
(cages) per treatment, each with 6 males and 6
females.
Interval of access
to yeast
Lifetime number of eggs
laid per female per day
in artificial fruit
Never access
Every twelfth day
Every eighth day
Every fourth day
Every other day
Every day
0.03
1.34
1.47
3.11
5.10
3.85
were laid when females ingested protein every fourth,
eighth, or twelfth day.
Conclusions
Our combined laboratory studies show that both
sexes of apple maggot flies need to feed and drink at
least every other day or every third day just to be able
to move about and survive. They also indicate that
while continuous access to carbohydrate in the form of
sucrose is sufficient to permit long life and reasonable
movement, females need to acquire protein at least
every other day to maintain a high level of reproduc-
tion. In nature, it is quite likely that under many con-
ditions females do not have continuous access to such
high quality protein as we offered them in our labora-
tory cages. Therefore, in nature it is probable that most
females take in smaller meals of lower quality protein
than females did in our laboratory cages and that they
need to do so on an every-day basis to sustain high
fecundity. This probably explains why we observed so
many apple maggot females, even late in the season,
away from fruiting host trees and feeding on non-host
plants. Thus, females in nature may not be prone to
spend long periods in orchards having little supply of
insect honeydew, bird droppings, or other protein
sources. To reiterate what we suggested in the first
article in this series, protein-seeking females may be
quite responsive to the odor of chemicals emitted from
protein sources (for example, ammonia). Such chemi-
cals could be useful, in addition to synthetic fruit odor,
in attracting females to interception traps on perimeter
apple trees.
Acknowledgements
We thank Maryam Mashayheki and Patti Powers
for their help during various aspects of these studies.
This work was supported by the Science and Education
Administration of the USDA under grant 8700564
from the Competitive Grants Office, and by the Massa-
chusetts Agricultural Experiment Station Project 604.
Fruit Notes, Summer, 1990
13
Apple Bruising V. Apple Bruising Related to
Picking and Hauling Practices
William J. Bramlage
Department of Plant & Soil Sciences, University of Massachusetts
Here we continue a series of articles on apple
bruising, reporting results from an on going study at
Michigan State University. The information contained
herein comes from a report presented at the 1989 Inter-
national Summer Meeting of the American and Cana-
dian Societies of Agricultural Engineers in Quebec,
Canada, June 25-28, 1989. The research was con-
ducted by C. L. Burton, G. K. Brown, W. L. Schulte
Pason, and E. J. Timm of USDA's Agricultural Re-
search Service and the MSU Agricultural Engineering
Department.
In a previous article [Fruit Notes 54(2):3-5] we
showed that much bruising during apple harvesting
and handling is avoidable and that in commercial op-
erations, use of bin trailers reduced bruising during
transit. The authors recommended that bin trailers be
equipped with soft tires and soft suspensions. Careful
forklift operation reduced bruising and long (rather
than short) lines on the fork lift also reduced bruising.
The study reported here attempted to identify and
quantify sources of bruising during bin-filling and
handling, and to determine if foam-plastic bin liners
would reduce bruising. Golden Delicious apples were
used in the study.
Bin-Filling
To study bin-filling operations, apple picking buck-
ets were emptied into an unpadded hardwood bin or
one with a 1/2-inch thick foam pad on the bottom.
Buckets were emptied either gently (approximating a
well-supervised picker) or roughly (approximating
80
fc*
70-
60-
50
CO
Q.
g 40
.52 30
E
m
20-
10-
\ss/\ Bottom Layer
I 1 Middle Layer
t£S3 Top Layer
^
^
'ZZX
^
^
i
M
Esa
Pad Ma Pad
Front
Pa* No Pa*
Rear
Pad, Ma Pod
Short Tines
< Bin Carrier >
Pad Ma Pad
Long Tines
< Fork— Lifts >
Pad Ma Pad
X— Action
Figure 1. Percent bruising incurred on apples at different positions in foam padded or unpadded bins
during orchard transportation.
14
Fruit Notes, Summer, 1990
pickers collecting drops for cider). A "mechanical
apple" [Fruit Notes 54(l):6-7] was placed in picking
buckets used by commercial pickers to obtain data in
the field.
Rough filling into an unpadded bin bruised 89% of
the apples, with an average of over 2 bruises per fruit.
The foam pad reduced this to 64% bruising and 1.4
bruises per fruit. Gentle filling resulted in 28% bruis-
ing (0.35 bruises per fruit), which was not reduced by
the foam pad.
Gentle filling did not cause enough impact for the
"mechanical apple" to register data. Rough filling
always caused impacts to be recorded. In the field tests,
the "mechanical apple" recorded impacts in two-thirds
of the trials. However, these impacts were mostly of
low velocity and seemed to be more associated with
bucket filling than bucket emptying.
Orchard Handling
Four transport systems were evaluated: ( 1 ) a self-
loading bin carrier; (2) a standard rear tractor fork-lift
with short tines; (3) a standard rear tractor fork-lift
with long tines; (4) a cross-action air-shock rear tractor
fork-lift with long tines. Half of each bin was padded
with 1/2 inch of foam on the floor and 1/4 inch of foam
on the sides, while the other half of the bin was not
padded. Damage-free apples were positioned in the
bottom, middle, and top layers of fruit on both the
padded and unpadded sides of the bin. The bins were
transported about 1.25 miles over a combination of
paved, gravel, and orchard roads, and the fruit were
then examined for bruising.
Without padding 12% of the fruit in a bin on the
front of a bin loader were bruised and 50% of the ones
in a bin on the rear of the bin loader were bruised.
About 22% of these bruises were 1/2 to 3/4 inch in
diameter. On the forklifts, 22 to 32% of the fruit
became bruised during transport, regardless of type of
forklift, with nearly all of the bruises being less than
1/2 inch in diameter. In most cases, padding reduced
bruising but the greatest benefit occurred where most
bruising occurred, that is, in the rear bin on a bin
carrier. In this situation, padding reduced bruising
from 50% to 21%. Most of the bruising (and bruise
reduction) occurred where fruit were in contact with a
side of a bin during rough transport. The results of
these tests are summarized in Figure 1.
Road Transport
To measure the effects of methods of transporting
80
70-
60-1
«o 50
-3*
a.
g 40-
.<2 30
E
CD
20
10
l 1 Total
crr?\ Top Level
fs7s^3 Middle Level
Bottom Level
r-xn Sides
Pad No Pad
Truck
Pad No Pad
Trailer
Figure 2. Total apple bruising incurred during truck and trailer transportation.
Fruit Notes, Summer, 1990
15
bins of fruit from orchard to packing house, bins were
transported in either a 20-bin stake-body truck or a 16-
bin tri-axle, fifth-wheel hitch trailer pulled by a pickup
truck. Tests were set up just as in the bin-carrier
orchard tests. Bins were transported 7 miles over
mostly gravel roads, at speeds of 20 to 25 mph.
Overall, 58% of the fruit transported by truck and
38% of those on the trailer sustained bruises. On the
truck, bruises averaged 0.9 per fruit and on the trailer,
0.53 per fruit. Padding reduced bruising in both types
of transport. As in the orchard, most bruising and
bruise reduction occurred where fruit were in contact
with the side of the bin. However, padding in the
bottom of the bin also had some benefit. Results of this
study are summarized in Figure 2.
The results of this study suggest that padding of
bins is a practical way to reduce bruising, but in fact,
padding is usually not feasible since it will interfere
with air movement during cooling and with water
movement if the fruit are dipped or drenched.
What these findings do provide is insight into how
and where bruising occurs and what a grower might do
to reduce bruising when it is a serious problem.
Clearly, most bruising during transport occurs where
fruit contact the bin and in a typical situation, about
1/3 of the apples in a bin are in contact with the wood.
They also suggest that design and construction of
bins need re-evaluation, to see if alternatives might
lessen impact bruising. Improvements in transporta-
tion equipment also may be helpful; for example, use of
air-suspension systems may be advantageous.
Finally, what these studies continue to demon-
strate is that careful training and supervision are the
key to controlling bruising during harvesting and
transport of apples. Some bruising is inevitable, but
the amount of bruising that occurs is in the hands of the
orchard manager and supervisor.
*t» •!* «j> *.%» *t*
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The Fifth International Controlled
Atmosphere Research Conference
The Fifth International Controlled Atmosphere
Research Conference was held June 14-16, 1989, in
Wenatchee, WA, and Proceedings of that Conference
are now available.
These Conferences grew from the New England-
New York CA Conferences held some 20 to 25 years ago
and have become truly international in scope, with 18
countries represented at the 1989 Conference. The
Proceedings of the 1989 Conference come in two vol-
umes, totalling 882 pages, and depict the "state-of-the-
art" of Controlled and Modified Atmosphere research.
The Conference covered a very wide range of top-
ics, including basic and applied research, controlled
and modified atmospheres, many different commodi-
ties, and very specific as well as general topics. It also
included a series of papers examining the relationships
of mineral content to quality retention in CA storage.
The scope of the Proceedings perhaps can be de-
scribed best by a listing of the sections in it. Volume 1
considers Pome Fruits (apples and pears) and is organ-
ized into sections on "Fundamental Studies", "Min-
eral Nutrition", "Apple Maturity", "Control of Storage
Disorders/Diseases", "Quality Preservation", "Tech-
nology", and "Global Considerations".
Volume 2 deals with "Other Commodities and
Storage Recommendations" and contains the follow-
ing sections: "Fundamental Studies", "Control of
Storage Disorders/Diseases", "Quality Preservation",
and "Technology". The Volume concludes with "Stor-
age Recommendations for Fruits, Vegetables, and
Ornamentals". For apples and pears, these recom-
mendations are broken down by cultivar, but for the
other commodities recommendations and comments
are presented for a crop as a unit.
These Proceedings contain a wealth of information
for persons interested in the current thinking about
Controlled or Modified Atmosphere Storage of crops.
They can be obtained as follows. Send a check or money
order for $35 (U.S. or Canada, $45 for other countries)
made payable to "WSHA-CA Conference", to:
Proceedings
WSHA-CA Conference
1100 N. Western Avenue
Wenatchee, WA 98801
16
Fruit Notes, Summer, 1990
Controlling Postharvest Diseases of
Apples and Pears
Editors' Note: The following information has been taken from a series of articles in the
December, 1989, issue of the Postharvest Pomology Newsletter, published by the Washing-
ton State University and the U.S. Department of Agriculture, Wenatchee, Washington.
Postharvest Diseases and Disorders of
Apples and Pears
Several of the more common postharvest diseases
and disorders of apples and pears are described below.
Gray Mold (Botrytis cinerea). Botrytis rot is a com-
mon decay of apples and pears. This fungus enters
through punctures and wounds; therefore, minimizing
fruit injury will reduce the amount of decay from this
fungus. The source of Botrytis spores is the orchard.
The fungus grows and sporulates abundantly on dead
and dying plant material found in orchard cover crops,
especially during cool, moist weather. Infection can
occur in the orchard or at any time in the handling
process that the spores come in contact with unpro-
tected fruit wounds or susceptible tissue. These ini-
tially rotted fruits spread the disease to fruit in contact
with them to produce nests or pockets of decaying fruit.
The disease is often called nest or cluster rot.
Blue Mold (Penicillium expansion). Blue mold is a
common destructive rot found on fruits in storage and
at the market. It is generally considered a wound
parasite, but it can penetrate through lenticels, par-
ticularly those near bruises. Late in the storage season
when fruit has been weakened by ripening and aging,
most cultivars are susceptible to lenticel infection. The
infection can start when pears or apples are handled
carelessly during the packing process. Environmental
conditions such as moisture, ventilation, and tempera-
ture directly influence the development of decay. The
fungus grows well at humidities normally found in cold
storage. Poor ventilation around storage containers
leads to increased moisture around the fruit and slower
cooling times, increasing the risk of infection. Like-
wise, delays in cooling fruit after harvest also increase
the chance of blue mold. Careful fruit handling, pack-
inghouse sanitation, prompt fruit cooling, and proper
temperature management during the storage period
are keys to reducing blue mold.
Alternaria Rot (Alternaria alternata). Alternaria rot
may occur on apples and pears in any production stage.
This fungus lives on dead and decaying plant tissue in
the orchard, and its spores contaminate fruit in the
orchard or during the handling process. The amount of
decay depends on the condition of the fruit. Infection
usually occurs through breaks in the skin or other
weakened areas caused by sunburn, bruising, chemical
injury, or scald.
Bull's Eye Rot (Pezicula malicortids). Bull's eye rot
infections occur in the orchard as well as after harvest,
becoming established in the fruit at any stage of devel-
opment from petal-fall onward. The rot usually begins
at open lenticels and develops slowly at cold storage
temperatures. The rot does not spread from one fruit
to another. The spores that infect fruit come from can-
kers on branches of apple trees in the orchard. In the
tree, this disease is called perennial canker. These
cankers often start around old pruning cuts and are
associated with woolly aphid feeding. Cankers are not
produced on pear trees, but the fungus colonizes in-
jured or dead bark. Preharvest fungicides will help
prevent bull's eye rot. Harvested fruit should not be
left in the orchard during rainy weather.
Mucor Rot (Mucor piriformis). Mucor is a soil-borne
fungus that grows well even at cold temperatures. The
fungus grows in fallen fruit on the orchard floor so any
practice that reduces rotting fruit in the orchard or
movement of spore-laden soil into the packinghouse on
bins will help to reduce Mucor problems. There is no
effective fungicide registered for control of Mucor.
Side Rot (Phialophora malorum). Side rot can affect
both apples and pears but is most severe on pears,
particularly Bosc. Similar symptoms can be caused by
the fungus Cladosporium herbarum. However, since
Cladosporium is sensitive to commonly used posthar-
vest fungicides, and Phialophora is not. The latter has
been the major cause of side rot losses. Spores of this
fungus also enter the packinghouse on bins or fruit con-
taminated with orchard soil.
Practices to Minimize Postharvest Decay of
Apples and Pears
Preharvest
•Maintain good weed control, and keep grass mowed.
A drier orchard microclimate will reduce Mucor rot,
Coprinus rot, and scab.
Fruit Notes, Summer, 1990
17
Table 1. Chemical control
measures for postharvest diseases of apples and pears.
Disease
Fungicide
Rate
Application notes
Mucor rot,
None
Proper sanitation, adequate sorting,
Alternaria rot,
and effective use of SOPP or chlorine
Cladosporium rot,
dioxide are the only measures
and Side rot
available for these decays.
Blue mold,
Deccosalt No. 19
575 grams/
Constantly agitate mixture; label also
Gray mold,
(TBZ)
300 gal water
allows spray application prior to wax
and Bull's eye rot
(500 ppm)
575 grams/55 gal
wax (2700 ppm)
at 575 grams/75 gal water (2000
ppm).
Captan 50W
2.5 lbs/100
Apply as dip or drench; recharge
gal water
suspension when water volume in
tank is reduced by 25%; add 1.0 lb per
25 gal water added.
Topsin - M
0.5-1.0 lb/100
Requires continuous agitation; do not
(apples only)
gal water
mix with chlorine or other highly
alkaline agents; do not dip fruit for
more than 2 minutes
1.0-2.0 lbs/100
When added to wax, apply flow-
gal wax
-through sprays.
Mertect 340-F
16floz/100
Continuous agitation required; treat
gal water
fruit as a dip, drench, or spray for 3
minutes or less; no more than 2 post
harvest applications allowed on
apples; only one postharvest
application allowed on pears; cannot
be mixed with wax.
SOPP
1 gal/ 100 gal
Use in immersion-type bin dumpers;
(22.6% AI)
rinse fruit with fresh water after
treatment; test SOPP concentration
daily, recharge if needed, replace
frequently; if the dump wash is above
70°F, reduce concentration to 0.2-
0.25%; above 80°F, do not use
SOPP; in some years Bartletts are
very susceptible to SOPP injury; if a
packing house plans more than one
treatment with SOPP during the
packing cycle, consult the SOPP
manufacturer for instructions.
• Control woolly aphids to reduce bull's eye rot of apple.
• Supplement fruit calcium with foliar sprays during
the growing season. High calcium fruit is less prone to
decay and disorders than low calcium fruit.
•Use the minimum amount of nitrogen fertilizer nec-
essary to maintain plant vigor. High N fruit are more
prone to various postharvest problems than lower N
fruit.
18
Fruit Notes, Summer, 1990
•To avoid development of resistance in the packing-
house do not use Benlate or other benzimidazole fungi-
cides in the orchard. Resistance to Benlate will reduce
the effectiveness of other postharvest fungicides in-
cluding Mertect 340-F and Deccosalt No. 19.
Harvest
•Harvest at proper maturity. Late-picked fruit is more
susceptible to decay than fruit of optimum maturity.
•Clean bins thoroughly before filling. Steam is most
effective.
•Reduce bin contact with dust and dirt which contain
spores of decay fungi. Keep the bottom of bins as clean
as possible. Keep staging areas mowed. Suppress dust.
•Avoid picking fruit when it is wet.
• Keep grounders (fallen fruit) out of bins.
•Do not allow bins of fruit to remain inthesun. Trans-
fer fruit quickly to the packinghouse and cold storage.
•Handle fruit gently. Avoid bruising and stem punc-
tures. Smooth orchard roads and driving forklifts and
bin trailers slowly may reduce fruit injury.
Postharvest
•After harvest, remove fallen fruit from orchard to
prevent buildup of decay spores.
•Apply copper at leaf-fall to help reduce bull's eye rot.
Bin Drench
• Use a fungicide and change solution regularly to avoid
buildup of fungal spores such as Mucor that are not
controlled by fungicides.
Packing Line
• In the dump tank use sodium hypochlorite or calcium
hypochlorite at 100 ppm available chlorine or SOPP
(Steri-Seal D or Stop Mold F) at 0.3 to 0.5% to kill
spores of decay fungi. For pears, use sodium sulfate
flotation salt with chlorine or lignin sulfonate (Orzan,
Lignosite 458, Lignosite 50) with SOPP. Do not mix
chlorine with SOPP. Do not use chlorine with lignin
sulfonate.
•Monitor concentration of chlorine many times each
day. Add chlorine continuously with a pump rather
than just once a day. Keep chlorinated dump tank at
Ph 6 to 8 for best results, but do not acidify solutions
containing sodium silicate.
• The surfactant AG98 (Rohm and Haas) improves the
effectiveness of chlorine. Use 0.3% AG98 and increase
the initial chlorine charge by about 10X to obtain 100
ppm chlorine. For pears, allow about 1 hour for flota-
tion salt to dissolve and tank specific gravity to stabilize
between adjustments. Do not use surfactants with
Topsin, Captan, or Mertect.
•If using SOPP, dump tank water may be sterilized
with heat. Remove all fruit from tank, cover tank with
styrofoam or canvas, heat to 130°F and hold at that
temperature for 25 minutes. Allow water to cool before
dumping fruit into it. Ensure good ventilation during
heating. Approximately 10%waterlossand25% SOPP
loss occur during heating and need to be replaced. Do
not heat water containing chlorine.
•Minimize depth of immersion of fruit when dumping
bins. Immersion forces contaminated water into
wounds and cores and increases rot.
•Fruit should receive a thorough fresh water rinse
after leaving the dump tank and flumes.
•Design line to minimize damage to fruit. Avoid sharp
edges and drops that wound or bruise fruit.
•Apply fungicide prior to storage.
Storage
• Clean cold room thoroughly with a high pressure hose
and a commercial disinfectant labelled for food han-
dling areas. Several formulated products are available
for this purpose. Most of these products contain so-
dium or calcium hypochlorite, chlorine dioxide, or-
ganic acids such as phosphoric or acetic acid or quater-
nary ammonia compounds often referred to as
"quats".
•Do not pack and store wet fruit. Dry thoroughly
before storage. Do not wrap wet pears in copper-
treated paper or staining may result. Keep relative
humidity in storage only high enough to avoid shrivel.
• Keep temperature in cold room as low as possible.
Packaging
• Copper-treated wraps reduce spread of gray mold and
Mucor rot.
•Use packaging material that minimizes bruising and
injury of fruit during transit.
Shipping
•Handle fruit gently and carefully.
• Keep fruit cold.
Fruit Notes, Summer, 1990
19
Blueberry Culture
Dominic A. Marini
Cooperative Extension, University of Massachusetts
This article gives highlights of a presentation by
Dr. Gary Pavlis, Rutgers University, at the New Eng-
land Small Fruit and Vegetable Growers Convention,
November, 1989.
In selecting a site for blueberries, look at the natu-
ral vegetation- wild blueberries, azaleas, and other
acid loving plants indicate a favorable site for blueber-
ries. A soil with high organic matter content, good
drainage, and which is well aerated is preferred. Heavy
clay and poorly drained soils are not desirable. Blue-
berries can be under water during the dormant season
but not during the growing season. In New Jersey,
some blueberries are being planted on ridges on wet
soils.
Mulching is highly desirable. Mulch insulates the
soil in hot weather, maintaining lower soil tempera-
tures-blueberry roots stop growing at high soil tem-
peratures. Mulches also help control weeds-blueber-
ries are poor competitors. Mulches conserve soil mois-
ture and supply nutrients as they decompose. Disad-
vantages of mulches are their expense, labor cost of
application, sheltering of mice, and the danger of fires.
Spring planting is preferred. With fall planting,
heaving during the winter is a possibility.
Cultivar selection depends on your market-pick-
your-own, retail, or wholesale. Patriot does well on
upland soils in New Jersey; Spartan does not. Bluecrop
is the leading cultivar in New Jersey. Eliot is sour
when it first turns blue-wait 4 or 5 days to harvest.
Elizabeth, Darrow, and Coville have good flavor.
Irrigation is necessary on light soils in New Jersey,
2 inches every 10 days, either overhead or trickle.
In New Jersey, most blueberries are grown with
clean cultivation. This practice helps to control
mummy berry. Sod middles are good for pick-your-
own.
Bees may be needed for pollination at the rate of 0.5
to 2 hives per acre, depending on cultivar. Some
cultivars are more attractive to bees and require fewer
hives per acre, while unattractive cultivars require
more.
Iron deficiency can be a problem on soils with high
pH. It is advisable to test the pH every year.
When it comes to fertilizer, the ammonium form of
nitrogen is preferred. Do not use fertilizers containing
potassium chloride (muriate of potash), since chlorine
is harmful to blueberries.
Recommended planting distances in New Jersey
are 3.5 or 4 feet by 10 feet. On new plantings, do not
apply any fertilizer in the planting hole; wait until new
growth begins.
On new bushes, remove fruit buds. In the second
year, prune twiggy growth, low horizontal branches,
and fruit buds. In the third year, you can leave some
fruit. In the fourth year, allow bushes to fruit if they
have made good growth.
Incorrect pruning or lack of pruning is the main
cause of poor growth and low yields with blueberries.
As canes grow older, over 5 years, they become less
productive. In pruning, remove dead and diseased
canes. Then remove 1 of every 6 canes. Remove the
oldest canes and low, spreading canes. Cut at ground
level, do not leave stubs-stubs block new canes and are
a source of disease innoculum, such as Phomopsis.
Open up the center of the bush to allow sunlight to
penetrate. Wear gloves when pruning. Use both
hands, one to hold the primer and the other to knock off
twiggy growth.
20
Fruit Notes, Summer, 1990
News from Other Areas
Editors' Note: The following item is reprinted from Garden, the journal of the Royal
Horticultural Society, London, England. It updates an article seen previously in Fruit Notes
[54(4): 11] on the British National Fruit Collection.
National Fruit Collection Safe
After a year of uncertainty, the future of the Na-
tional Fruit Collection has been secured. When, in
March last year, the Ministry of Agriculture, Fisheries
and Food announced its proposal to close Brogdale
Experimental Station in Kent, the present home of the
Collection, unless alternative funding was found, there
was serious concern that this unique and internation-
ally renowned source of genetic material would be lost.
While the fate of Brogdale was being decided, the
Society's Garden at Wisley (the Collection's original
home), Wye College, and East Mailing Trust were
considered as possible sites for the collection. Also,
Swale Borough Council offered to manage the Collec-
tion at the Brogdale site.
However, on December 14 last year the Ministry
announced that Brogdale was indeed to close on March
31 and confirmed that they had decided that nearby
Wye College, Ashford, Kent, offered the Collection the
best prospects for its future. As part of the University
of London, Wye will be able to ensure the Collection's
long-term security and independence from other fruit
research and breeding activities, in particular for Plant
Variety Rights testing.
The Collection, which will be under the manage-
ment of Peter Dodd, dates back to the nineteenth
century. It contain approximately 2,400 different apple
varieties, 500 pears, 350 plums, 220 cherries, 320 bush
fruits, and 42 cobnuts, as well as varieties of vines and
ornamental prunus.
The transfer to Wye will take about five years to
complete, as new plantings have to be propagated from
existing trees.
*1* *f* *£* *?* *%
•j* «j» «j» #j» #j»
IN MEMORIAM
William T. Pearse, 1903-1990
William T. (Bill) Pearse, a leader of the Massachu-
setts fruit industry and a long-time supporter of the
University's Fruit research program, passed away on
March 21, 1990.
Born in Moretonhampstend, England, Bill came to
the U.S. as a child. He graduated in Pomology from the
Stockbridge School of Agriculture. A lifelong member
of the Massachusetts Fruit Growers' Association
(MFGA), he was employed in the Marketing Division
of the Massachusetts Department of Agriculture and in
the Middlesex County Extension Service, and for many
years was an operational consultant for J. P. Sullivan
and Company, Ayer, Massachusetts.
Bill was a major figure in the MFGA. As Chairman
of the University of Massachusetts Fruit Advisory
Committee, he was an outspoken advocate for both the
fruit industry and the University's Pomology program.
Shortly before his death, Bill was named a Life Mem-
ber of MFGA in recognition of his many contributions.
Bill's voice was a familiar sound at fruit grower
meetings for many years. Intensely interested in fruit
growing and in learning new things, his many ques-
tions were in search of better ways to get the job done
right. Among his legacies is the development of fruit
IPM in New England, which he strongly encouraged
and greatly helped become established in commercial
orchards.
He is survived by his wife, Louise, by his daughters
Brenda and Cynthia, and by his sons David and Bill.
His family requested that memorial contributions be
made to either the Horticultural Research Fund, c/o
the Massachusetts Fruit Growers Association, Box
632, North Amherst, MA 01059, or to the Carroll
Center for the Blind, 770 Centre Street, Newton, MA
02158.
With Bill's passing, a dedicated pomologist and
true friend was lost.
Fruit Notes, Summer, 1990
21
Damage to Maturing Apples by Birds
James A. Parkhurst
Department of Forestry and Wildlife Management, University of Massachusetts
Results from recent research in the Hudson Valley
of New York may be of interest to producers of early-
maturing apple cultivars. Using a variety of survey
techniques together with on-site inspections at 13 or-
chards, researchers from Cornell University and the
USDA Denver Wildlife Research Center evaluated the
nature, extent, and severity of bird damage to ripening
apples (condensed from Tobin, M. E., R. A. Dolbeer,
and P. P. Woronecki. 1989. Bird damage to apples in
the mid-Hudson Valley of New York. HortScience
24:859).
When asked to evaluate the extent of damage
attributable to birds on maturing apples (within 1 to 14
days of harvest), growers responded that less than 1 %
of their apples were affected, and at only four sites was
damage believed to exceed 10 % overall. In contrast,
researchers found evidence of bird damage (peckings)
in 57 % of the trees that they sampled during on-site
inspections, and nearly 6 % of all apples had been
pecked. Common crows were identified as being re-
sponsible for most damage, although a host of other
species were suspected (including house finch, Ameri-
can goldfinch, cedar waxwing, blue jay, common
grackle, and European starling). Because their re-
search was conducted in orchards with known damage
(i.e., a non-random sample), these researchers believe
that their figures represent the extreme rather than a
regional average. Regardless, their estimates point out
that growers may be underestimating the extent of
damage.
Of greater significance were findings that the tim-
ing of fruit maturation and fruit color may affect bird
depredation. Early-maturing cultivars (e.g., Jersey-
mac, Jonamac, Paulared, and Tydeman) sustained the
greatest amount of damage from birds. Late-maturing
cultivars that exhibited a red coloring earlier in the
season (e.g., Cortland, Empire, and Rome) also were
damaged. In every case where bird depredation was
recorded, a blush of red was found on the affected
apple.
Although pockets of exceptionally high damage
may exist locally, these researchers maintain that bird
depredations are of minor concern regionally. Of
greater concern is the evidence that damage may be
focused on early-maturing cultivars, particularly in
light of the current trend toward, and increasing acre-
age in, these cultivars.
If you believe that you are experiencing problems
with bird depredations, you may contact the USDA
APHIS Animal Damage Control office in your state for
on-site technical assistance and control suggestions.
Requests for animal damage control information and
educational programs may be directed to your Coop-
erative Extension office or through your local Coopera-
tive Extension agent.
22
Fruit Notes, Summer, 1990
Assessing Effects of Depredation by Deer
on Apple Production
James A. Parkhurst
Department of Forestry and Wildlife Management, University of Massachusetts
Hungiy deer regularly visit apple orchards
throughout the Northeast, particularly during winter
months when preferred native foods are scarce or
unavailable. The extent of damage caused by deer
browsing is extremely variable, depending upon or-
chard location and local deer population levels; damage
in areas of high deer density can be extensive. A need
presently exists for a means to assess the impact of deer
depredations, but devising an easy and consistent
method to predict accurately fruit production losses
stemming directly from deer browsing has been diffi-
cult. Most previous methods were either too compli-
cated to use in the field, or were based upon question-
able assumptions. Recently, two researchers at Utah
State University devised what they believe to be a reli-
able method of estimating apple production loss in the
first crop following winter browsing by deer [Austin, D.
D. and P. J. Urness. 1989. Evaluating production
losses from mule deer depredation in apple orchards.
Wildlife Society Bulletin 17(2):161-165]. The following
is a summary of their methodology and findings.
Methods
Tests were conducted from 1983 to 1986 using
semi-dwarf and standard-sized Red Delicious trees
ranging in age from 8 to 15 years. Because test plots
were located outside the typical summer range of the
deer studied, only winter browsing damage was as-
sessed. To allow comparisons between browsed and
unbrowsed trees, deer browsing pressure within or-
chards was regulated through use of 8 ft-high fencing.
Data collected and enumerated included: a) number of
intact and nipped buds (counted prior to or during the
period of bud swelling), b) number of flower clusters,
c) number of apples on trees (pre-harvest), d) number
of hand-harvested apples, and e) mean weight of
apples within and above the browsing zone. Bud
counts were made by counting terminal buds on the
current year's growth plus all buds and bud spurs
greater than 1 cm (2.54 in) in length along the second
year or older growth. Counts of flower clusters within
and above the browsing zone were made just before
opening (during late-pink bud stage) . Researchers also
examined variation in apple production within trees
and between trees.
Results
1 . Where whole trees were measured, the number of
apples harvested declined as the percentage of buds
removed increased. When bud removal exceeded 20%,
significant reductions in apple production were noted.
For example, at 31% bud removal, apple production
over the whole tree declined 49%.
2. The percentage of apple production lost in the first
crop following depredation was approximately propor-
tional to the percentage of bud removal due to browsing
(i.e., at 30% bud loss, 30% of apple crop within browsing
zone was lost).
3. Production of apples above the browsing zone was
not affected by browsing occurring in the lower sec-
tions of the tree.
4. Browsing by deer had no effect on the individual
weight of apples produced within the browsing zone
(mean weight varied from 182 to 186 g per apple
throughout the study). It was determined that weight
of harvested fruit is dependent upon the ratio of leaves
to fruit rather than upon selective browsing of deer.
How to Assess Damage
To determine the potential loss of fruit production
in mature orchards (trees 6 years and older that are
producing a harvestable crop), the researchers offered
the following guidelines (see example provided). This
information was condensed from a manual developed
as a guide for producers to determine the impacts of
depredation on production (Austin, D. and P. J.
Urness. 1987. Guidelines for evaluating annual crop
losses due to depredating big game. Utah Division of
Wildlife Resources, Publication No. 87-5, Salt Lake
City, UT. 40pp.).
1. Determine nipping losses. Just prior to trees
breaking dormancy and before leaves and flower clus-
ters become noticeable, randomly select 15 representa-
Fruit Notes, Summer, 1990
23
EXAMPLE
Table 1 . An orchard with 400 mature Delicious apple trees received overwinter depredation by deer. Data
collected from trees necessary to determine impact of depredation on fruit production for the first crop
following depredation.
Bud and nip
counts
Flower cluster counts
(2 branches per tree)
(Browsing Zone
or 2m height)
Tree
Loss
Within
number
Buds
Nips
(%)
Within
Above
(%)
1
80
10
10/90 = 11.1
58
220
58/278 = 20.9
2
75
16
16/91 = 17.6
110
310
110/420 = 26.2
3
115
32
32/147 = 21.8
54
175
54/129 = 41.9
4
58
10
10/68 = 14.7
78
225
78/303 = 25.7
5
60
0/60 = 0.0
77
230
77/307 = 25.1
6
55
35
35/90 = 38.9
98
245
98/343 = 28.6
7
70
15
15/85 = 17.6
71
155
71/226 = 31.4
8
88
19
19/107 = 17.8
126
395
126/521 = 24.2
9
92
22
22/114 = 19.3
60
330
60/390 = 15.4
10
65
13
13/78 = 16.7
72
320
72/392 = 18.4
11
41
3
3/44 = 6.8
84
240
84/324 = 25.9
12
59
18
18/77 = 23.4
63
300
63/363 = 17.4
13
65
21
21/86 = 24.4
52
340
52/393 = 13.3
14
92
5
5/97 = 5.2
70
315
70/435 = 16.1
15
101
8
8/109 = 7.3
Total = 242.6
62
235
62/297 = 20.9
Total = 351.4
Mean % loss = 16.2%
Mean % clusters within = 23.4%
- 1,600 bushels were harvested and sold @ $8/bu or $6 net profit
- apples harvested within browsing zone = 1,600 x 23.4% = 374.4 bu
- percent of potential production harvested within the browsing zone = 100.0% - 16.2% loss = 83.3%
- therefore, 374.4 bu harvested / 0.838 = 446.8 bu potentially harvestable if depredation had not occurred
- net loss = 446.8 - 374.4 = 72.4 bu lost to depredation
- value = 72.4 bu x $6 per bu = $434.40
tive trees in the orchard. If more than one cultivar is
present, select 15 trees per cultivar.
2. Select two major branches on opposite sides of the
main trunk but within the browsing reach of deer (ap-
proximately 6 ft). On small trees, use the entire tree.
Beginning at the main trunk, follow the branch along
smaller and smaller branches to the end. At each
junction, select the larger branch and continue follow-
ing it within the browsing zone. Record all intact and
all nipped buds (terminal buds of the current year's
growth and all buds along second year or older stems
where those buds protrude greater than 1 cm in
length).
3. Calculate the mean percentage of bud removal as:
total nips / (total buds + total nips)
Then determine the mean for all 15 trees combined.
4. Estimate the proportion of trees within browsing
reach of deer. This is most easily done when trees are
in the early bloom stage. Randomly select 15 trees of
each cultivar (although it is suggested that the same
trees used in the nip counts be used, it is not necessary).
Mark each tree with plastic flagging around the trunk
at browsing height (about 6 ft); if browsing extends
below or above 6 ft overall, adjust height accordingly
but browsing height must be consistent among all 15
24
Fruit Notes, Summer, 1990
trees. Select a twig near the periphery of the tree and
mark it with piece of flagging. Beginning at this point,
walk slowly around the tree counting all flower clusters
within the browsing zone (i.e., below the flagging on
trunk). Then repeat the count for all clusters above the
browsing zone. (Counts of flower clusters take about
10 minutes per tree.)
5. Determine the percentage of tree within the
browsing zone as:
clusters of flowers within zone / (flower clusters
within + flower clusters above browsing zone)
Determine the mean for all trees combined.
6. Determine harvest and net value of crop. In Fall,
immediately after harvest, record the total number of
bushels of apples produced and the average selling
price per bushel (minus any costs for picking, storage,
or transportation).
7. To determine impact of depredation:
a. Multiply the number of bushels harvested by
the percentage of flower clusters within the browsing
zone. This calculation will give the number of bushels
produced within the browsing zone.
b. The number of bushels that would have been
harvested within the browsing zone if depredation had
not occurred can be determined using the relationship
between percentage of buds removed to percentage of
first crop lost following depredation. This can be
calculated as:
bushels harvested within browsing zone
[(100-% bud removal) x 100]
c. Determine bushels of harvest lost by subtract-
ing potential harvest before browsing from the actual
harvest within the browsing zone.
The procedure for determining losses in young
orchards (1 to 5 years old) is similar to that for mature
orchards except that bud counts are made over the
entire tree rather than on selected branches, because
the entire tree is accessible to deer for browsing.
Final Note
Although there is some evidence suggesting that
overall tree vigor and potential fruit production may be
negatively impacted for several years following initial
depredation, these researchers stressed that their
method of assessi ng deer browsing impact is applicable
only to the first crop following depredation. They could
not separate the effects of other confounding factors
(seasonal variability within trees, differences in annual
weather conditions, etc.) from the effects of depreda-
tion when they tried assessing impact on potential
production in subsequent years. Research is continu-
ing on this aspect of the problem.
Fruit Notes, Summer, 1990
25
Fruit Notes
University of Massachusetts
Department of Plant & Soil Sciences
205 Bowditch Hall
Amherst, MA 01003
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Fruit Notes
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autlo and William J. Bramlage
ISSN 0427-6906
C3
r
en
Volume 55, Number 4
FALL ISSUE, 1990
Table of Contents
Costs of Establishing High
Density Apple Plantings
Use of Soap as a Repellent for
Deer in Apple Orchards
Light, a Key Factor in Efficient Apple Production
BIOLOGICAL
j90
— — —
Management and Economics of a
Small Low-Input Apple Orchard
Nectarines for Massachusetts?
Fruit Notes
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Fruit Notes
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Costs of Establishing High Density
Apple Plantings
Wesley R. Autio
Department of Plant & Soil Science, University of Massachusetts
In the 1989 New England Apple Survey [Fruit
Notes 54(4):12-17] growers stated that 62% of the
apple acreage to be planted in 1990-94 would be on
dwarfing rootstocks. This figure is a dramatic
change from the 15% reported for 1985-89, showing
that the industry is moving to more intensive man-
agement systems which may be more economically
sound [Fruit Notes 53(l):4-7], easier to prune and
harvest, and use less spray material (because of the
reduction of spray material required per acre).
However, growing an apple tree on a dwarfing root-
stock is not the same as growing one on a free-
standing, semi-dwarf or standard rootstock. Grow-
ers must be aware of the different level of expertise
and inputs required. A previous Fruit Notes
[54(4):6-10] article described some of the horticul-
tural techniques required to manage intensive sys-
tems; however, before choosing a system it is critical
to know something about the cost of establishing and
maintaining it.
To become more familiar with the peculiarities of
these systems and to obtain accurate data on costs,
I established a trial of four training systems at the
University of Massachusetts Horticultural Re-
search Center (Belchertown) in the spring of 1990.
This trial includes Nicobel Jonagold/M.9 trained as
a small central leader, as a slender spindle, as a
vertical axis, and on 4-wire, vertical trellis. These
systems were established with the monetary sup-
port of the Massachusetts Fruit Growers' Associa-
tion and a University of Massachusetts alumni
donation. In this article I will detail the establish-
ment costs of each system, and in future articles I
will discuss management problems and costs as the
trees develop. Anyone interested in visiting the
planting is welcome to do so; each system is clearly
labeled.
Small Central Leader
With the small central leader systems each tree
is supported by a 1-inch (O.D.) conduit pipe stake
protruding 7 feet above the soil surface. Trees are
spaced 8 feet in the row and 14 feet between rows,
giving a density of 389 trees per acre. These trees
will be trained with a relatively low input technique,
using zig-zagging of the central leader, limb re-
newal, and other pruning techniques as described in
the New England Apple Production Guide. The best
way to describe them is that they will be maintained
similarly to free-standing, semi-dwarf trees, but will
be small and supported by a stake.
After laying out the orchard, tree holes were dug
with a 24-inch, tractor-mounted soil auger to a depth
of 24 inches. Conduit stakes were driven 12 inches
into the bottom of the hole. After planting, trees
were headed at 34 inches above the soil. Each tree
was tied once to the post using a mechanical tying
device (Max Tapener™). The costs of establishing an
acre of small central leader trees are detailed in
Table 1.
Slender Spindle
The slender spindle system also produces a
central leader tree. In this trial slender spindle trees
were established similarly to the small central
leader in that they were individually supported on
conduit pipe stakes; however, they are spaced 6 x 14
feet (519 trees per acre) and will have a more inten-
sive training regime. Limbs will be tied down to
encourage early fruiting and reduce growth, the
leader will be bent to reduce growth, and summer
pruning will be used to reduce potential regrowth.
Establishment was similar to that described for
the small central leader, except the time required to
perform each task was increased because of the
greater number of trees per acre. Costs are de-
scribed in Table 2.
Vertical Axis
The vertical axis tree is also a central leader,
except no attempt is made to control the growth of
the leader. Trees are supported by tall stakes. As
a tree grows, the leader, if not pruned, will eventu-
Fruit Notes, Fall, 1990
Table 1. The cost of establishing one acre of small central leader apple trees.
Input
Cost
Materials
Trees (389 @ $5.25)
Stakes (389 @ $2.45)
$ 2042
953
Labor ($8.00 per hour)
Tree holes (32.4 hours)
Stake installation (19.4 hours)
Tree planting (19.4 hours)
Tree heading (0.9 hours)
Tree tying (0.9 hours)
259
156
156
7
7
Equipment (Tractor plus 2' soil auger -
- $20 per hour)
Tree holes (16.2 hours)
324
Total cost per acre
$ 3904
Table 2. The cost of establishing one acre of slender
spindle apple trees.
Input
Cost
Materials
Trees (519 @ $5.25)
Stakes (519 @ $2.45)
$ 2723
1271
Labor ($8.00 per hour)
Tree holes (43.2 hours)
Stake installation (25.9 hours)
Tree planting (25.9 hours)
Tree heading (1.2 hours)
Tree tying (1.2 hours)
346
207
207
10
10
Equipment (Tractor plus 2' soil auger -
- $20 per
hour)
Tree holes (21.6 hours)
432
Total cost per acre
$ 5206
ally "fruit out" and stop extending in height. Inmost is growing into the next tree's space, or has fruited
cases with dwarf trees this "fruiting out" occurs at 10 heavily and is drooping. A major advantage of the
to 12 feet. Therefore, no input is required to control vertical axis system is that it requires only very
leader growth. Lateral growth is removed only if it simple pruning strategies. A major disadvantage,
is growing strongly upright (usually done in June), however, is that it will become a tree which is 10 to
Fruit Notes, Fall, 1990
Table 3. The cost of establishing one acre of vertical axis apple trees.
Input
Cost
Materials
Pressure treated posts - 4"x4"xl4' (31 @ $10.30)
$ 320
Pressure treated posts -- 4"x4"xl2' (62 @ $8.85)
551
End post anchor (31 @ $5.00)
156
Wire for post to anchor (545 feet @ $0.02)
11
Eye bolts -- 3/8" x6" with washers (31 @ $1.00)
31
Eye bolt, 18" rod, coupling, washers (31 @ $2.59)
81
Spring-tights (31 @ $5.95)
185
Wire (6285 feet @ $0.02)
132
Trees (519 @ $5.25)
2723
Bamboo stakes (519 @ $2.40)
1245
Wire for tying stakes to wire (519 feet @ $0.01)
5
Labor ($8.00 per hour)
Post holes (12.4 hours)
100
Post installation (12.4 hours)
100
Anchor installation and attachment (11.4 hours)
91
Marking and drilling holes in posts (4.0 hours)
32
Hardware installation (1.3 hours)
10
Wire installation (7.8 hours)
62
Tree holes (43.2 hours)
346
Stake installation (1.7 hours)
14
Tying banboo to wire (18.2 hours)
146
Tree planting (25.9 hours)
207
Tree tying (2.4 hours)
19
Light pruning (1.2 hours)
10
Notching (4.8 hours)
39
Equipment (Tractor plus 2' soil auger -- $20 per hour)
Post holes (6.2 hours)
124
Tree holes (21.6 hours)
432
Total cost per acre
$ 7172
12 feet tall.
In this planting trees were spaced 6 feet apart in
the rows, with rows 14 feet apart, giving a total of 5 19
trees per acre.
A major cost in the establishment of a vertical
axis system was the support structure (Table 3).
Each tree was supported by a 12-foot bamboo stake
which extended 10 feet above the soil surface. These
stakes were tied to 2 horizontal wires (6 and 10 feet).
Wires were supported by 4"x4" pressure-treated
posts. End posts were 14 feet long and were buried
4 feet deep. Six-inch anchors were used to secure end
posts. Intermediate posts were 12 feet (buried 3 feet
deep) and were spaced 40 feet apart. Twelve-gauge
wire (at 6 and 10 feet) was attached to one end post
through 6"x3/8" eye bolts extending through the
posts. At the other end, 4"x3/8" eye bolts were
coupled to 18 inches of 3/8" threaded rod and con-
nected through the end post. A spring tensioning
device (Spring-Tight™, Brookside Industries, Tun-
bridge, VT 05077) was attached to the eye bolt, and
the wire was attached to the spring tensioning
Fruit Notes, Fall, 1990
device. The extended eyebolt allows 18 inches of Vertical Trellis
tension adjustment to account for expansion and
contraction from winter to summer. The spring ten- A Previous Fruit Notes article [53(l):4-7] sug-
sioning device automatically performs an immediate S ested that a Mclntosh/M.9 tree trained to a vertical
adjustment to short-term temperature changes. trelhs was significantly more productive and gave
Wire was passed through 1/2-inch holes drilled in better returns than one trained as a small central
the intermediate posts. leader supported by a post. Hence, a vertical trellis
Trees were approximately 6 feet tall after plant- was included in this trial. Much more support is
rm. ji.i.i_LLii i given to a tree on a trellis than one on a post, since
mg. They were tied to the bamboo stakes in two ° n , u ^ „_4.„j Tr> tU; „ „, £ t „
locations. Because most lateral branches on these
trees originated above 40 inches, 8 buds were
notched on each tree between 24 and 30 inches above In this trial a 4-wire trellis was used, with wires
the soil to encourage a low tier of branches. Any a t 24, 44, 64, and 74 inches above the soil surface.
laterals which were very strongly upright at plant- The support structure was established similarly to
ing were removed. that described for the vertical axis, except all posts
were shorter (12-foot end posts and 10-foot interme-
all branches are supported. In this planting, trees
were spaced 8 feet in the rows and 14 feet between
rows.
Table 4. The cost of establishing one acre of apple trees supported by a 7'
4-wire, vertical trellis.
Input
Cost
Materials
Pressure treated posts - 4"x4"xl2' (31 @ $8.85)
$ 275
Pressure treated posts - 4"x4"xl0' (62 @ $7.49)
466
End post anchor (31 @ $5.00)
156
Wire for post to anchor (545 feet @ $0.02)
11
Eye bolts - 3/8" x6" with washers (62 @ $1.00)
62
Eye bolt, 18" rod, coupling, washers (62 @ $2.59)
161
Spring-tights (62 @ $5.95)
370
Wire (12570 feet @ $0.02)
264
Trees (389 @ $5.25)
2042
Labor ($8.00 per hour)
Post holes (12.4 hours)
100
Post installation (12.4 hours)
100
Anchor installation and attachment (11.4 hours)
91
Marking and drilling holes in posts (7.4 hours)
59
Hardware installation (2.6 hours)
21
Wire installation (12.4 hours)
100
Tree holes (32.4 hours)
259
Tree planting (19.4 hours)
156
Tree heading (0.6 hours)
5
Equipment (Tractor plus 2' soil auger - $20 per hour)
Post holes (6.2 hours)
124
Tree holes (16.2 hours)
324
Total cost per acre
$ 5146
Fruit Notes, Fall, 1990
diate posts - all extending 7.5 feet out of the soil) and
no individual tree stakes were used. Trees were
headed at planting 2 inches below the bottom wire to
force adequate branching for the bottom wire.
Establishment costs of the vertical trellis system
are given in Table 4.
Conclusions
The costs of establishing intensive systems are
high. It is estimated that a free standing system of
trees on M.7 spaced 16 x 23 feet would cost $749 per
acre to establish. If each tree were individually
staked it would cost $1088 per acre, only 28% of the
cost of the cheapest of the systems described in this
trial (small central leader). This relationship should
not cause you to abandon your interest in intensive
systems. These intensive systems will begin produc-
ing earlier, will have higher yields, will have greater
packout, and will require lower harvest, pruning,
and spraying inputs than the larger trees on M.7.
These characteristics will likely make them more
profitable than the semi-dwarf systems using M.7
rootstocks.
*sL» +L* *L» *sL» *L*
0^% 0^% 0^% #^p% rp»
The ideal slender spindle.
From: Oberhofer, H. 1987. Developing the high density
orchard step by step. Compact Fruit Tree 20:66-69.
Fruit Notes, Fall, 1990
Use of Soap as a Repellent for Deer in
Apple Orchards
James A. Parkhurst
Department of Forestry and Wildlife Management, University of Mas-
sachusetts
Browsing by white-tailed deer (Odocoileus vir-
ginianus) in apple orchards often causes tree defor-
mation, reduces anticipated fruit production, and in
recently established blocks, may prevent a grower
from realizing any economic return on investment
because of delays in producing the first crop. Many
methods to reduce impacts of deer browsing have
been tried over the years, each with varying success.
A technique that many claim to be economical and
that provides reasonable effectiveness is the use of
bar soap as a repellent. Researchers at The Con-
necticut Agricultural Experiment Station recently
studied the use of soap as a deer repellent by evalu-
ating the radius of effectiveness and examining
differences among brands [Swihart, R. K. and M. R.
Conover. 1990. Reducing deer damage to yews and
apple trees: Testing Big Game Repellent, Ro pel, and
soap as repellents Wildlife Society Bulletin
18(2): 156-62]. This article sum-
marizes their findings.
Methods
Researchers conducted tests
in 2 different orchards contain-
ing either all standard trees or a
combination of standard and
semi-dwarf trees during the
winter of 1988-89. Eight com-
mercially available brands of bar
soap (3.5-oz size) were used
(Table 1). Each bar of soap, with
its wrapper intact, was hung
from a lateral branch within the
browsing zone. Bars were spaced
a minimum of 25 yards apart
(within and between rows). Be-
cause investigators also wanted
to determine if visual cues,
rather than odors, were impor-
tant in providing repellency pro-
tection, they hung empty,
washed soap wrappers from
trees in a fashion similar to the soap bars. The
effectiveness of soap and wrappers as repellents was
determined by measuring the amount of browsing
damage in December, just prior to the placement of
the test devices, and then again in February and
April after the devices were installed. Extent of
browsing impact was assessed by recording damage
to terminal shoots on 25 randomly selected twigs at
various distances (0-1, 1-2, 2-3, 4-6, and 9-11 yards)
from the hanging test devices.
Results
When compared with damage observed on un-
protected trees within the same block, browsing was
reduced 70% within 1 yard of a soap bar, whereas a
91% reduction was noted within 1 yard of an empty
soap wrapper. However, the mean percentage of
Table 1. Effect of bars of 8 brand
5 of soap, wrappers only, or no
treatment (control) on the mean
percent (±SE) of apple twigs
browsed by white-tailed deer in 2 Connecticut orchards, Decem-
ber 1988 to April 1989. Condensed from Table 4
, pg. 160 in
Shihart, R. K. and M. R. Conover.
1990. Reducing deer damage
to yews and apple trees: testing Big Game Repellent 1 *,
Ropel",and
soap as repellents. Wildl. Soc. Bull. 18(2): 156-162.
Mean percent (• SE) of
Brand of soap
apple twigs browsed
Dial"
1.7 «
► 0.4
Cashmere Bouquet 8
1.9 <
' 0.4
Ivory R
2.3 <
' 0.7
Shield R
2.5 <
• 0.6
Coast"
2.6 '
• 0.6
Irish Spring"
2.7 '
• 0.6
Safeguard"
2.7 «
» 0.6
Jergens"
3.6 «
» 0.7
Wrapper Only
4.2 «
' 0.9
No Treatment (Control)
5.2 <
> 0.9
Fruit Notes, Fall, 1990
browsing damage within a block was lower where
soap bars were present than with empty wrappers.
Researchers did not find any significant differences
in repellency among the various brands of bar soap
they tested, even though subtle variations in the
amount of browsing damage incurred were noted
(Table 1). Distance away from a test device was an
important characteristic relative to the success of
the repellent; effectiveness of both soap and wrap-
pers decreased with increasing distance (greater
than 1 yard) from the test device.
Implications for Growers
With regard to the brands of soap tested in this
study, none proved to be much better or worse
overall in its ability to repel browsing deer. How-
ever, these researchers noted that the lack of de-
tected differences among brands may be due, in part,
to the relatively low level of browsing pressure in
their test orchards. They advised that cost may be a
better determining factor rather than brand for
those growers thinking of implementing a control
program using soap as a repellent.
More importantly, the spacing of soap bars was
critical in determining the level of effectiveness
realized. These researchers recommend using a
spacing of 1 yard between bars throughout the or-
chard. Therefore, some of the earlier recommenda-
tions offered to growers (e.g., 1 bar for each produc-
ing tree in a row and 1 bar for every other young,
non-producing tree in a row) may not provide suffi-
cient protection against browsing damage.
At the recommended 1-yard spacing, approxi-
mately 1200 bars of soap/acre would be needed to
provide adequate protection. At $0.39/bar for a 3.5-
oz bar, the estimated cost/acre would be $470, or
$530 including labor (at $6/hour). In contrast, at
$0.05/bar for a 0.5-oz bar of soap, as some growers
have been using, the cost/ acre would be reduced to
$60, or $120 with labor. These researchers provided
no indication of whether smaller bars of soap per-
form as well as larger ones do, but the useable life
expectency of smaller bars certainly would be
shorter (depending upon weather conditions).
In addition, these researchers did not provide
any indication of whether or not a combination of
soap bars and empty wrappers, alternately spaced at
1 meter, would provide reasonable protection, but at
a much reduced cost than using all soap. These
questions need to be addressed in the near future.
•X* ^1-* *!-* *X* *X*
rp» #^S 0^% *y% ^J>»
Fruit Notes, Fall, 1990
Light, a Key Factor in Efficient Apple
Production
James T. Williams
Cooperative Extension, University of Massachusetts
Light interception in the orchard and its distri-
bution throughout the tree canopy affects flower bud
formation, fruit set, fruit development, and fruit
quality. Orchardists can use pruning and tree
training to maximize the light interception of the
orchard, and therefore the orchard efficiency. This
article will review light as it relates to maximizing
fruit production and quality. Much of the informa-
tion for this article is from: Rom, C. R. and B. H.
Barritt. Light interception and utilization in or-
chards, pp. 41-59. In A. B. Peterson (ed.). Intensive
Orcharding. Goodfruit Grower, Yakima, WA.
If 100% of the sunlight received by an orchard
was absorbed, the ideal situation would exist.
However, this situation is impractical, because there
must by open spaces to allow equipment operation
and harvesting. Research has determined that or-
chard production is maximized when 70% or more of
the light striking an orchard is utilized. The earlier
in the life of the orchard that maximum light utiliza-
tion occurs, the quicker maximum production is
attained. Therefore, trees must develop leaf surface
quickly and over a large portion of the land area to
be most efficient. In Washington, well-feathered
trees will develop approximately 22 square feet of
leaf area in their first year and up to 63 square feet
in their second year. This growth will be less in New
England due to the reduced available sunlight.
Obviously, increased tree density will affect total
light utilization in the first few years after planting.
When one considers the whole tree, fruiting spur
leaves make up 15 to 25% of the total canopy leaf
area, non-fruiting and vegetative spurs may com-
prise 30 to 40% of the leaf area, and the remaining 30
to 40% of the leaf area is composed of extension shoot
leaves. Approximately a month after spur leaves
emerge they are unable to maintain fruit growth at
proper rates so the larger leaves emerging from
spurs (called bourse shoot leaves) and normal vege-
tative shoot leaves supply carbohydrates for fruit
growth. Vegetative spur leaves supply carbohy-
drates to the fruit, but of more importance, assist in
flower but formation. These leaves must receive
ample light during the time of flower bud formation.
Research has shown that only about 15% of the light
energy intercepted by a leaf passes through, the rest
being either absorbed or reflected. The closer to the
center or bottom of the tree, the less light is avail-
able. When light travels 3 to 6 feet through the tree
canopy, its light energy is reduced to 30% and at that
point falls below the threshold that a leaf needs.
Therefore, it becomes evident that dense tree cano-
pies limit growth and development in almost 1/3 of
the canopy volume. In order that fruit quality,
flower bud formation, and fruit growth be maxi-
mized, 30 to 50% of the full sunlight is necessary so
that photosynthesis can function at efficient levels.
Only then can wood growth, leaf growth, fruit
growth, and fruit sugars be developed fully. Addi-
tionally, light is also important for fruit color. The
fruit must be hit directly by 50 to 75% available
sunlight in order that anthocyanin pigments be
developed and skin color maximized.
It is important that leaves be exposed to maxi-
mum sunlight at the beginning of the season, be-
cause those leaves that are shaded early in the
season and then exposed to full sunlight never attain
a rate of photosynthesis equal to those leaves that
were exposed to full sun for the entire season. Proper
light management is necessary from the beginning
of the season to the end. A combination of dormant
and summer pruning and a high density training
system maximizes the light throughout the tree
canopy.
Trees "remember" the low light intensities re-
ceived the previous year by providing fewer flowers,
lower fruit set, and smaller fruit. Light manage-
ment is a very important operation to improve pro-
duction, fruit quality, and repeat crops, and should
be regarded as a continuous function in the orchard.
Next issue will discuss seasonal light require-
ments in the orchard.
vL* *X» *X» *L» «J>»
«^p% *f% 0^% r^» *J+
Fruit Notes, Fall, 1990
Management and Economics of a Small
Low-input Apple Orchard
Ronald J. Prokopy
Department of Entomology, University of Massachusetts
Hundreds of different pest species (arthropods,
diseases, weeds and vertebrates) can affect growth
and productivity of apple trees. Two fundamentally
different approaches can be taken to manage this
complex of pests.
One approach involves a comparatively harsh
level of human intervention and high input of off-
farm materials. For the past 5 decades, nearly all
commercial apple orchardists in the eastern United
States have used this approach, which even under
the most modern, widely-practiced integrated pest
management system usually involves annual appli-
cation of 5 to 8 insecticide, 2 to 3 acaricide (including
oil), and 10 to 13 fungicide sprays, along with herbi-
cide against understory plants, and toxic bait
against mice.
The other approach combines modest human
intervention with low input of purchased materials,
particularly chemical pesticides. This approach,
currently practiced by only a few commercial pro-
ducers in the eastern United States, accents cul-
tural, biological, host-tree resistance, and behav-
ioral methods of pest management. Intervention
with pesticide is a last resort, a step taken only when
all other measures have fallen short of acceptable
pest suppression. If commercially feasible, this
approach offers promise of sustainable fruit produc-
tion with minimum adverse impact on soil and water
quality and on other organisms, including beneficial
arthropods, microorganisms, humans, and other
vertebrates.
In a 1985 article [Fruit Notes 50(2):2-5], I re-
ported results from 1981-84 of using a low spray
program for managing apple arthropod pests in my
small orchard in Conway, MA. In this article, for the
same orchard, I present management practices and
results from 1985-1989 of a low-input management
program for all classes of orchard pests, including ar-
thropods, diseases, weeds, and vertebrates. Besides
data on pest levels in the orchard and neighboring
unmanaged trees, values are given for variable and
fixed costs involved in operating the orchard and
gross return from sale of fruit. In addition, compari-
son is made with cost of operating a typical Mcintosh
orchard in the Hudson Valley of New York.
Management Practices
The orchard (2/7 acre) consists of 30 Liberty, 5
Prima, and 5 Priscilla bearing apple trees plus 5
Liberty and 5 Freedom apple trees not yet bearing,
all on M.26. The canopy of bearing trees averaged
about 10 feet in diameter and 10 feet in height in
1989. Woods border the orchard on the North and
East, beginning about 15 feet from perimeter apple
trees. Open field, stretching for about 300 feet,
borders on the South and West. Ten unmanaged
apple trees, some annually bearing fruit, are 600 to
800 feet from the orchard. Annually, the orchard re-
ceives about 50 pounds of cow manure per tree in
early April and 15-20 pounds of lime per tree in
November.
Arthropod management . Arthropod pest control
was accomplished by a combination of cultural,
behavioral, biological, and pesticidal means. Sev-
eral arthropod pests active early in the growing
season were managed through application of pesti-
cide. Hence, superior oil (60-70 viscosity) at 4 gallons
per acre was applied annually with a shoulder-
mounted, motor-driven mist blower at the tight-
cluster stage of bud development against overwin-
tering eggs of the European red mite and overwin-
tering San Jose scale. Phosmet (Imidan) at 5 pounds
per acre plus the residue-extending agent NU-
FILM-17™(Miller Chem. Co., Hanover, PA) at 1 pt
per acre was sprayed at or shortly after petal fall and
again 10 to 14 days later, primarily against plum
curculio. In my judgement, more than any other in-
secticide, phosmet affords effectiveness against
plum curculio and relative safety to humans and
beneficial predators of apple pests. Phosmet sprays
were timed carefully to coincide with the appearance
of fresh curculio egglaying scars, usually monitored
on a daily basis for 2 to 3 weeks beginning at petal
fall. These sprays also controlled developing larvae
of European apple sawfly and speckled green fruit-
Fruit Notes, Fall, 1990
worm, as well as first-generation adults, eggs, and
larvae of codling moth, lesser appleworm, and sev-
eral species of leafrollers. Later generations of these
lepidopteran pests were managed culturally
through removal (in 1980) of all apple, pear, haw-
thorn, and quince trees within 600 feet of the or-
chard perimeter to create a host-free zone suffi-
ciently broad to discourage immigration of females.
In addition, dropped apples were removed on a
weekly basis from mid-August through harvest to
prevent within-orchard lepidopteran pest buildup.
Apple maggot flies were managed behaviorally
by capturing females on unbaited red wooden
spheres, 3.5 inches in diameter and coated with
Tangletrap™. They were hung at the rate of 1 to 2
per tree (depending on fruit load) from early July
through harvest. The Tangletrap coating was not
replenished after traps were hung. Insects and
debris were removed twice (at monthly intervals)
before harvest.
Foliar pests such as mites, aphids, leafminers,
and leafhoppers were suppressed biologically
through the action of beneficial predators and para-
sitoids that developed in the absence of pesticide use
from June onward.
Disease management . Disease control occurred
primarily through the high level of resistance of all
4 cultivars to apple scab, and the moderate to high
level of resistance to cedar apple rust, powdery
mildew, and fireblight. There was, however, no
obvious resistance to the summer diseases sooty
blotch and flyspeck. Neither of the latter perma-
nently scar or deface fruit. Rather, toward harvest,
they appear as dark blotches or spots on the fruit
surface, which were removed completely during my
normal practice of cleaning the surface of each
harvested apple with a damp cloth before packing
apples in boxes for sale.
Weed management . Beginningin 1985, orchard
understory growth was controlled through mulch-
ing with hay under the tree canopy and periodic
mowing. In late April, about 3/4 bale of hay was
spread annually beneath each tree, extending about
a foot from the tree trunk to the perimeter of the
canopy. The mulch effectively prevented growth of
understory plants beneath the canopy, conserved
soil moisture, and provided nutrients to the tree.
Remaining mulch was removed in late August to
prevent establishment of overwintering mice be-
neath it. Alleys between the trees were mowed 5
times at monthly intervals, beginning in May.
Vertebrate pest ma nagement . Beginning in
1984, mice were controlled culturally(l) through
mowing alleys between trees (as just described) to
deprive mice of protective plant growth, (2) through
the absence of plant growth beneath the tree canopy
during autumn and winter as a consequence of
mulching from April through August, and (3)
through use of mouse guards around tree trunks.
Beginning in 1985, deer were repelled from
feeding at developing branch terminals and flower
buds by hanging a bar of scented soap (Cashmere
Bouquet R ) in each tree in June.
In 1989, flocking birds (particularly crows, blue-
jays, and starlings) were repelled from alighting on
the trees and pecking into the fruit by suspending
Scare-Eye R balloons (Pest Management Supply Co.,
Amherst, MA) 3 to 4 feet above the uppermost tree
foliage at 44-foot intervals. The balloons were
emplaced in mid-August (when the first bird-pecked
fruit were seen) and removed in late September
(near the end of harvest). The 44 foot distance
between balloons was based on a preliminary trial in
1988 using a single balloon; bird damage to fruit
averaged 1.5% at 22 feet from the balloon, 11.7% at
44 feet and 20.6% at 66 feet.
To evaluate effectiveness of this pest manage-
ment approach, at 3-week intervals during the grow-
ing season, foliar populations of spider mites,
aphids, leafminers, and leafhoppers were assessed
on a presence/absence basis by examining 10 termi-
nal shoots or 10 leaves on each of 10 randomly
selected fruiting trees. Comparison was made be-
tween insect and disease injury levels on harvested
fruit within the orchard versus levels on 4 unman-
aged trees 600 to 800 feet away. Samples consisted
of 25 to 30 randomly selected fruit per tree. On all
trees, only fruit acceptable for marketing as U.S.
Fancy grade were assigned to the "pest-free" cate-
gory. For vertebrate pests, comparison was made
between damage levels before and after manage-
ment procedures were employed in the orchard.
Results
For all 5 years combined, an average of 94.7% of
the fruit sampled in the orchard at harvest was free
of insect injury compared with 0% fruit free of insect
injury in the unmanaged trees (Table 1). In the
orchard, plum curculio (2.5%), tarnished plant bug
(1.1%), and apple maggot (0.6%) accounted for about
80% of the total insect injury. On the unmanaged
trees, plum curculio (95.4%), apple maggot (91.6%),
and codling moth (47.8%) were the principal causes
of insect injury.
For all 5 years combined, average peak popula-
10
Fruit Notes, Fall, 1990
Table 1. Pest injury to harvested apples in a small low-input commercial apple orchard and on nearby
unmanaged apple trees in Conway, MA.
Class
of
pest
Years
Avg. no.
fruit
sampled/
Trees year
Avg. annual % fruit injured by'
Insects
Diseases'
1985-89 Orchard 1154
1985-89 Unmanaged 100
1985-89 Orchard 1154
1985-89 Unmanaged 100
% Pest-
TPB EAS GRW PC CM LAW LR AMF" Other free
1.1 0.3 0.1 2.5 0.3 0.1 0.2 0.6 0.1 94.7
3.0 12.6 9.3 95.4 47.8 0.2 7.1 91.6 1.8 0.0
AS CAR BR Other
0.0
64.8
0.2
0.0
0.1 0.0
0.6 0.0
99.7
34.6
Birds
Vertebrates
1989 Orchard
1414
0.4
1985-88 Orchard
1089
11.9
99.6
88.1
"TPB=tarnished plant bug; EAS=European apple sawfly; GFW=green fruitworm; PC=plum curculio;
CM=codling moth; LAW=lesser appleworm; LR=leafroller; AMF=apple maggot; AS=apple scab;
CAR=cedar apple rust; BR=black rot.
b An average of 588 AMF/year was captured on the sticky red sphere traps.
'Fruit blemished by sooty blotch or fly speck were not classed as injured because the symptoms could
be removed completely by cleaning with a damp cloth.
tions per year of arthropod foliar pests in the orchard
were as follows: apple aphids and woolly apple
aphids, 35% and 6%, respectively, of foliar terminal
shoots sampled; combined two-spotted spider mites
and European red mites, 13% of leaves sampled;
apple blotch leafminers and white apple leafhop-
pers, each 2% of leaves sampled. In no year did
populations of any of these foliar pests approach
levels considered potentially injurious and requiring
intervention. Natural enemies apparently were suf-
ficient to suppress these pests.
An average of 99.7% of the fruit sampled in the
orchard was free of disease-caused scars at harvest
compared with 34.6% on the unmanaged trees
(Table 1). In the orchard, cedar apple rust (0.2%) and
black rot (0.1%) accounted for all of the disease scars.
On the unmanaged trees, apple scab (64.8%) and
black rot (0.6%) comprised the disease pest injury.
During 1981-84, before use of mulching and
mowing to suppress weed growth, an average of 34%
of the trees had at least one mouse tunnel entrance
beneath the tree canopy in November. During 1984-
89, an average of only 4% of the trees had at least one
such tunnel entrance.
During 1981-84, before bars of soap were hung
on the tree branches, an average of 11% of the trees
showed signs of damage by deer. During 1984-89,
none of the trees showed injury. In early October
1989, soap bars were removed from all trees. After
3 months, 18% of the trees showed signs of deer
injury.
From 1985-88, before Scare-Eye balloons were
hung throughout the orchard, an average of 1 1 .9% of
fruit sampled at harvest was pecked by birds. In
1989, bird damage to fruit averaged only 0.4%. At
the end of harvest on October 1, 1989, all balloons
Fruit Notes, Fall, 1990
11
Table 2. On a per acre basis, pre-harvest costs of operating the Conway orchard (1989) are compared
with pre-harvest costs (for 1986) of operating a typical orchard of mature Mcintosh apple trees in the
Hudson Valey of New York State as reported by Castaldi (1987)
Cost
Conway
Hudson Valley
Category Type
Item
($ per acre)
($ per acre)
Variable Materials
Manure
_
Lime
53
-
Hay mulch
99
-
Fertilizer
-
56
Superior oil
11
-
Insecticide
32
71
NU-FILM 17
7
-
Acaricide
-
52
Fungicide
-
50
Herbicide
-
96
Mouse bait
-
10
Tangletrap
21
-
Soap
25
-
Bee rental
-
25
Thinning spray
-
11
Total material costs
248
371
Labor*
Manuring 1 '
128
.
Liming b
43
-
Mulching b
106
-
Fertilizing
-
3
Pruning and brush removal
149
229
Monitoring for plum curculio
10
-
Spraying
64
57
Mowing
106
22
Preparing, hanging, cleaning,
and removing red spheres
181
-
Hanging and removing balloons
32
-
Preparing and hanging soap bars
64
-
Thinning fruit by hand
42
50
Removing hay mulch
42
-
Picking up apple drops
42
-
Mouse baiting
-
3
Total labor costs
1009
364
Machinery
Fuel, maintenance, repairs
67
206
Total variable costs
1324
941
12
Fruit Notes, Fall, 1990
Table 2. Continued.
Cost
Conway
Hudson Valley
Category Type
Item ($ per acre)
($ per acre)
Fixed
Amortized orchard establishment' 588
Machinery depreciation,
775
taxes, insurance, interest, housing 4 41
300
Small equipment (depreciation)" 1 2
-
Red spheres, balloons 74
-
Annual real estate interest (or rental) 18
200
Annual real estate taxes 11
20
Total fixed costs
734
1295
TOTAL OF ALL COSTS
2058
2236
"All labor was valued at $6/hr.
b Includes time required for hauling materials to orchard from sources 4 to 6
miles
away and time
required for spreading.
'Represents cost of trees and costs incurred during orchard establishment (years 1-5) amortized over
20 years.
d Machinery and small equipment depreciation amortized over 10 years.
were removed. Of the 200 apples (scattered among
the 40 bearing trees) that remained unharvested on
October 1, none was injured by birds. By October 8,
however, 5% had received bird injury.
Economic Comparison with Typical
Commercial Orchards
How do production costs for the Conway orchard
compare with those for a typical commercial apple
orchard? Casta] di (1987) analyzed production costs
in typical mature commercial Mcintosh apple or-
chards in the Hudson Valley of New York State that
consisted of trees on M.7 and that received modern,
Yirst-stage" [Fruit Notes 52(3):9-12] integrated pest
management practices. On a per acre basis, total
pre-harvest costs for the Conway orchard (1989) and
the typical Hudson Valley orchard (1986) were
$2058 and $2236, respectively (Table 2). Pre-har-
vest costs of materials were $248/acre for the Con-
way orchard ($50/acre for pesticides) compared with
$371/acre for the typical Hudson Valley orchard
($279/acre for pesticides). Pre-harvest costs of labor
were $1009/acre and $364/acre, respectively. Thus,
the Conway orchard received a lower input of pur-
chased materials (particularly pesticides) but a
higher input of labor than a typical commercial
Mcintosh apple orchard in the Hudson Valley.
In 1989, mature trees in the Conway orchard
yielded on average about 3 bushels U.S Fancy fruit
per tree, valued at $60 when sold to supermarkets
that specialize in low-input produce. The typical
Hudson Valley commercial Mcintosh orchard
yielded about 2. 5 bushels ofU.S. Fancy fruit per tree,
valued at $43 when sold to supermarkets that do not
specialize in low-input produce. At about 177 trees/
acre, which reflects tree density in both the Conway
and typical Hudson Valley orchard, this would rep-
resent a gross return of $10,800 and $7,740, respec-
tively. If harvest, storage, and marketing costs were
considered equal for both types of orchard, and if
there were no monetary return on fruit that did not
qualify as U.S. Fancy, then return on investment
would be $3,238/acre greater for the Conway or-
chard [(10,800 - 2,058) - (7,740 - 2,236)].
Conclusions
Findings from 1984-89 in my small commercial
apple orchard in Conway, MA indicate that the
Fruit Notes, Fall, 1990
13
combination of cultural, biological, host-tree-resis-
tance, behavioral, and pesticidal practices used to
manage arthropod, disease, and vertebrate pests of
fruit yielded 94% undamaged fruit under conditions
of very strong pest pressure in the vicinity of the
orchard. The only pests not effectively controlled by
the practices employed were the diseases sooty
blotch and fly speck, which did not cause scarring of
the fruit. Their symptoms were removed after har-
vest by cleaning fruit with a damp cloth.
The practices employed in the Conway orchard
may be used effectively in relatively small commer-
cial apple orchards (up to perhaps 3 acres or so in
size) in eastern North America if reasonably-priced
qualified labor is available. Total costs of production
compare very favorably with large commercial or-
chards. For large commercial orchards, however,
shortage of labor may dictate against the value of
such practices as placing sticky red spheres on every
tree to control apple maggot flies and Scare-eye
balloons every 44 feet to deter flocking birds, picking
up dropped apples at weekly intervals to discourage
within-orchard buildup of insect pests, and placing
and removing mulch under every tree to suppress
weeds and mice. For such orchards, it would un-
doubtedly be more feasible to practice elements of
"second-stage" integrated pest management de-
scribed in Fruit Notes 55(l):4-9.
References
Castaldi, M., 1987. The cost of establishing and
operating a Mcintosh, Red Delicious, and Empire
orchard in the Hudson Valley of eastern New York ,
Cornell Univ. Ext. Bull. XB007.
+L* ^1* *X* \L* *st*
•^ r-jS +f% +J* *f%
14
Fruit Notes, Fall, 1990
Nectarines for Massachusetts?
Karen I. Hauschild
Cooperative Extension, University of Massachusetts
Nectarines have been a controversial fruit in
Massachusetts, largely as a result of mixed success
with the public. Many growers have complained that
nectarines do not sell well - their size often is not
competitive with West Coast fruit - or that adequate
pest management is lacking. Logic, however, dic-
tates that nectarines should be popular, if the afore-
mentioned problems can be overcome, since they
have all the good qualities of peaches but none of the
fuzz.
As part of a project to evaluate new and promis-
ing peach cultivars at the University of Massachu-
setts Horticultural Research Center, we have
planted four nectarine cultivars. We hope that one or
more of these cultivars will be a valuable addition to
the direct-market grower and will help dispel the
myth that "we cannot grow competitive nectarines."
Before I describe the cultivars that we have
chosen, I would like to comment on nectarine culture
-just a few points to keep in mi nd for producing fruits
of maximum size and quality.
• Newer nectarine cultivars have been hybridized
with peach cultivars for greater size potential.
• Nectarines, because of their lack of protective
"fuzz", ai£ more susceptible (in general) to insect
attack and fruit rotting organisms.
• Many nectarine cultivars are as hardy as, or
more hardy than, peach cultivars.
\/ Nectarines require more nitrogen than peaches
to produce good crops.
• Good management practices result in better
crops, implying greater consumer acceptance
and increased profitability for the grower.
Following are descriptions of the four nectarine
cultivars planted in 1990 at the Horticultural Re-
search Center.
Earliscarlet (Redhaven - 12 days) has excellent size
for an early cultivar, if properly thinned. Fruit are
scarlet red over bright yellow, firm, yellow, and
semi-freestone. Trees are productive and hardy.
Summer Beaut (Redhaven + 4 days) produces ex-
ceptionally large fruit for its season. Flesh is free-
stone, firm, yellow, juicy, and sweet. Fruits are solid
red and show resistance to brown rot. Trees are vig-
orous, and hardy.
Redgold (Redhaven + 29 days) is a high quality late
cultivar. Large fruit are freestone, yellow, and firm-
fleshed with red around the pit. Redgold is consid-
ered to be a good shipper. Buds are very winter
hardy.
Fantasia (Redhaven + 31 days) fruit are large, free-
stone, and red over yellow with firm, yellow flesh,
but are susceptible to bacterial leaf spot. Trees are
productive.
Additional cultivars that may be worthy of con-
sideration are the following:
Sunglo (Redhaven + 12 days) fruit are high quality,
midseason, red over yellow, and large.
Mericrest (Redhaven + 20 days) trees are hardy
with excellent flavored, freestone flesh.
*J^ ^L* *L* *X» *d*
*f% 0^% *f% 0^% rj^
Fruit Notes, Fall, 1990
15
Fruit Notes
University of Massachusetts
Department of Plant & Soil Sciences
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"ruit Notes
ISSN 0427-6906
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension,
*
United States Department of Agriculture, and Massachusetts Counties Cooperating. "^
Editors: Wesley R. Autio and William J. Bramlage
Volume 56, Number 1
WINTER ISSUE, 1991
BIOLOGICAL
JAN 2 2 1991
ISCIENCES LIBRARY
Table of Contents
Apple Bruising VI. Reducing Impact
Damage on Packing Lines
Apple Bruising VII. Damage Ocurrtng
During Intrastate Transportation
Storage Humidity Influences Quality of Mcintosh Apples
Catfaclng by Oak and Hickory Plant Bugs
in Massachusetts Peach Orchards
Evaluation of Amblyseiusjallacis Predatory Mites
on Apple Trees One Year After Their Release
Hunting Spiders in Second-stage IPM Apple Orchard Blocks
Massachusetts Apple IPM Program: Observations in 1990
Non-pesticidal Control of Summer Codling
Moths Through Habitat Management
Effect of Distance Between Traps on Interception
of Apple Maggot Flies on Perimeter Apple Trees
Strawberry Cultivar Screen for Tolerance
to Black Root Rot Disease Complex
Effects of Sulfur and Copper Fungicides
on Fruit Finish, Scab, and Soil Acidity
Flyspeck and Sooty Blotch: New Problems and New Ideas
Summer Pruning, a Continuing Look at the Benefits
In-row Rotary Tilling for Orchard Weed Control
Fruit Notes
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Fruit Notes
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University of Massachusetts
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is intended. The University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied,
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Issued by the University of Massachusetts Cooperative Extension, Robert G. Helgesen, Director, in furtherance of
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Apple Bruising VI. Reducing Impact
Damage on Packing Lines
William J. Bramlage
Department of Plant & Soil Sciences, University of Massachusetts
This is the sixth in a series of articles about apple
bruising, reporting results from a major program at
Michigan State University to identify and correct
sources of bruising, by far the greatest cause of
rejections of harvested apples and a major source of
lost income. The program is directed by Dr. G. K.
Brown and includes personnel from the MSU Agri-
cultural Engineering Department and the USDA
Agricultural Research Service.
We previously reported results from their 1987
study of apple bruising during mechanical sorting
and packing on commercial lines [Fruit Notes
53(4):15-17]. That study showed that nearly every
apple was bruised during the operation, and that the
average apple was bruised 5 times. Bruising was
primarily caused by inadequate padding, excessive
apple energy at transfer points, lack of curtains and
brushes to slow apple movement, excessive opera-
tion speeds, and uneven flow of fruit through the
packing lines. Here are reported follow-up packing
line studies that have been conducted by Brown's
groups (Brown, G. K., N. L. Schulte Pason, E. J.
Timm, C. L. Burton, and D. E. Marshall. 1989.
Apple Packing Line Impact Damage Reduction.
Paper No. 89-6050, American Society of Agricultural
Engineers, St. Joseph, MI 49085-9659).
Bruising During Packing Line
Operation
About 20 commercial packing lines in Michigan
were evaluated by passing bruise-free Golden Deli-
cious apples through the lines and measuring result-
ing bruises, and by passing a "mechanical apple"
[Fruit Notes 54(l):6-7] through each line and meas-
uring impacts incurred as it passed through each
line.
In this study, the average fruit sustained 4.3
bruises as it passed through these lines. The damage
was great enough so that the average fruit was
downgraded from U.S. Extra Fancy to U.S. No. 1
grade. However, the individual lines varied in their
destructiveness, causing from 2.3 to 5.8 bruises per
fruit. (One improperly run line caused 15 bruises
per fruit and was not included in the averaging.)
The lines had different numbers of transfer
points, but most had 10 or 11. The "mechanical
apple" showed that each transfer point can cause
bruising, but that they need not do so if properly
installed and padded. One line had 10 transfer
points, but only 4 caused bruising.
Following initial evaluations, the research
group worked with 7 of these lines to reduce the
impacting occurring as apples passed through the
lines. Tests were then repeated and bruising was
compared before and after making changes. In all
casesbruising was reduced by the changes, although
it was never eliminated. (The lowest figure reached
was 2.3 bruises per fruit.) The reduced damage was
directly related to the number of transfer points that
were effectively padded, and the amount of energy
removed from each transfer.
What Caused Bruising?
High impacts at transfer points were always
caused when the "mechanical apple" hit steel, wood,
conveyor belting over steel or wood, or hard plastic.
They also sometimes resulted from hitting apples. A
drop of only 1/2 inch onto steel will cause a bruise of
nearly 1/2 inch diameter on a Golden Delicious or
Paulared apple. A roll down a ramp, without some
kind of decelerating device (e.g., a drape) before
hitting a hard surface, will cause a bruise equal to
that caused by a straight drop from that height.
The transfer from the lift rollers or chains in the
water flotation tank to the drain sizer caused high
impacts in lines with long or steep ramps to the chain
sizer. The transfer into the washer caused high
impacts when there was a long or steep ramp into the
washer. Use of a transfer belt or ramp between the
washer and the waxer usually caused damaging
impacts. The transfer into the dryer caused the
highest impacts, because the apples directly hit the
steel rollers.
Transfers into the singulator and into the sizer
cup caused high impacts on many lines. The singu-
lator impacts were due to long and steep entrance
Fruit Notes, Winter, 1991
ramps, hard singulator rollers, unpadded steel side-
walls, and excessive speed. Sizer cup impacts were
due to poor timing between the singulator and the
sizer, large gaps between the singulator and sizer
cups, hard sizer cups, and sometimes the absence of
a fabric strip to bridge the gap between singulator
and sizer.
Transfer from the sizer cups to the collection
conveyor often caused high impacts. Some cups
dropped too early, others too late. Some apples hit
others on the conveyor, or hit against a poorly
padded sidewall.
Some lines routinely operated with up to 20% of
the apples overflowing the singulator, dropping over
the side into a return belt. This occurred when there
was a sustained mismatch of equipment speed, a
temporary surge in number of fruit due to a bin of
small apples, or poor delivery of apples to the singu-
lator. In most cases, the overflow apples were
damaged beyond grade tolerance.
How to Reduce Bruising?
The authors summarize as follows. "The best
ways to avoid high impacts are to: minimize height
change, so drop energy is minimized; use decelerator
devices (brushes, drapes, diverters, etc.) to dissipate
energy and control the fruit; pad all hard surfaces to
spread the impact force over a large area and simul-
taneously absorb energy in the padding to minimize
rebound; and convey apples in water to absorb en-
ergy, achieve uniform 'sheet flow' and avoid open
areas on mechanical equipment where apples accel-
erate down ramps. Reasonable operating speeds are
also important. High brush speeds in washer-waxer
units can cause many damaging impacts between
apples, and can throw apples into the dryer. High
speeds or improper timing for singulators and sizers
cause the apples to undergo high impacts to enter,
transfer, or exit these units."
They also observed that the best way to make 90*
to 180° turns before waxing was in water. They
suggested that new lines be designed so that all
apples return to a water flume after inspection for
rots and defects and before being elevated into the
washer, to insure uniform flow, minimize impacts,
and maximize the capacity of cup sizers. They noted
that transfers using brushes were much gentler
than ones using ramps, whether or not the ramps
had drapes or curtains.
Use of water flumes or water bins fillers at the
end of pre-sizer lines consistently caused few, if any,
impacts. Sponge-padded crossbars on the conveyor
leading to the water bin filler prevented impacts
during the filling operation.
Conclusions
It is shocking to observe the damage that occurs
as apples pass through the typical packing line. As
this study points out, sources of this damage are
identifiable and generally correctable. The authors
state, Tradition has allowed lines to be installed
with many of the problems found to cause bruise
damage." Changes can be made that will signifi-
cantly reduce damage, and these are usually inex-
pensive changes. "When installing new lines, tradi-
tion must be avoided if low damage is desired.
Manufacturers, installers, and owners can work
together to make low damage a reality."
Packing line operators should carefully examine
their lines in light of the information presented by
Brown and his group. Relatively simple, inexpen-
sive changes can do much to reduce, if not avoid, this
damage. Brown's study shows that all packing lines
cause unnecessary apple damage, so no one can
afford to ignore his suggestions.
From: Thomm. J.J. 1906. Tht American Fruit
Culturist. Orange Judd Company, New York.
Fruit Notes, Winter, 1991
Apple Bruising VII. Damage Occurring
During Intrastate Transportation
William J. Bramlage
Department of Plant & Soil Sciences, University of Massachusetts
Continuing this series of reports from the re-
search conducted by Dr. G. K. Brown and his associ-
ates at Michigan State University, here we summa-
rize their findings about damage that occurs during
truck transport of packed apples (Schulte Pason, N.
L., E. J. Timm, G. K. Brown, D. E. Marshall, and C.
L. Burton. 1989. Apple Damage Assessment during
Intrastate Transportation. Paper No. 89-6051,
American Society of Agricultural Engineers, St.
Joseph, MI 49085-9659).
Earlier reports from Brown's group have shown
that hand-harvesting and transportation to the
packinghouse caused an average of 4.5 bruises per
fruit, that grading and waxing added an average of
5.4 bruises per fruit, and that bagging added another
2.4 bruises per fruit. Here they sought to determine
the additional bruising that is occurring during
transport over varying distances and road condi-
tions, and to compare damage among common pack-
aging systems (bagmaster, pulp traymaster, and
foam cellmaster).
Procedures
Golden Delicious apples were carefully hand-
picked and handled to provide a minimum of fruit
damage. Any damage that had occurred before
packing was marked so as not to be attributed to
transportation. Size 138 fruit were used in these
tests for bagging, and placed in standard bagmaster
cartons. Size 113 fruit were packed into 24-count
polystyrene soft cell trays and placed in 96-count
foam cellmaster cartons. Size 100 fruit were packed
into 22-count paper pulp trays and placed in 88-
count traymaster cartons.
Packages were shipped from two packinghouses
to two distribution centers, and from each distribu-
tion center they went to three different retail stores.
The stores were 30 to 70 miles (short distance), 100
to 120 miles (medium distance), and 150 to 230 miles
(long distance) from the distribution centers. Trans-
port was in a double-axle, spring-suspension semi-
trailer. Samples were placed on the top of the last
two pallets at the
rear of the truck. Four "mechanical apples" [Fruit
Notes 54(l):6-7] were placed in traymaster and
bagmaster cartons in each shipment to record im-
pacts occurring during transit. After delivery to
stores, all fruit were examined carefully and their
damage recorded.
Results
Nearly all bruises incurred during this study
were small (1/2 inch in diameter or less). Upon
arrival in the stores, 39 to 98% of the fruit remained
undamaged. In the samples packed in polystyrene
foam, no more than 5% were bruised during transit.
In the bagged samples in bagmaster cartons, 10% to
50% were bruised, and in the pulp traymasters, 20%
to 61% were bruised. In 5 of the 6 shipments, the
traymaster cartons had the most bruised apples.
The results were then examined in terms of
distance shipped (Figure 1). For fruit packed in foam
cellmaster cartons, distance had no effect on bruis-
ing. In the other two packages, however, bruising
increased as distance traveled increased. Clearly,
the foam cellmasters protected the apples from
impacts due to road conditions, but neither the
bagmaster nor the pulp traymaster protected them.
This was borne out by the data obtained from the
"mechanical apples," which showed no bruise-caus-
ing impacts in the foam cellmasters, but increasing
numbers of such impacts in both the bagmasters and
the pulp traymasters, but with many more in the
pulp traymasters than in the bagmasters. More
impacts and more bruising occurred when trailers
were half full than when they were completely full.
It should be noted that these tests were con-
ducted in October and November, before the high-
ways were affected by winter's freezing and thawing
conditions. However, poor quality roads were en-
countered on all trips, and they caused most of the
impacts that were recorded. The results in Figure 1
probably represent a greater likelihood of encoun-
tering poor quality roads as travel distance in-
creases.
It should also be noted that handling of cartons
Fruit Notes, Winter, 1991
1 nn
I uu
▲ Pulp Traymaster
90-
* Bagmaster
80-
• Foam Cellmaster
g 70-
u_
r* => 0.880
-o 60-
0)
0)
S 50-
03
^"^ A _
A ^^
^^ « ■
^^ r - 0.602^,
£ 40-
o
v 30-
Q_
^<x^^^^ -
20-
10-
m r = 0.000
n_j
• • " • * •
u -1
1 1 1 T "'I 1 1 1 1— I 1 1 1 1 1 1 1 1 1 | 1 1 « | ■
100 200 300 400 500 600
Distance Traveled (km)
Figure 1. Percent of bruised fruit vs. total distance travelled, in traymaster, bagmaster, and
cellmaster cartons.
was carefully supervised in this study, so no drop-
ping of cartons or other willful abuse of them oc-
curred. Had the cartons been handled carelessly or
abusively, bruising would undoubtedly have been
greater, at least in the bagmaster or pulp traymaster
cartons.
These results show that bruising does occur
when packed fruit are transported, and that the
amount of bruising depends on the type of packing,
the road conditions, and the distance traveled.
Recognizing these facts may help packers and ship-
pers change some of their practices so that bruise
damage can be reduced. Once again, these results
show that bruising is a management problem, and
that it can be managed.
Fruit Notes, Winter, 1991
Storage Humidity Influences Quality
of Mcintosh Apples
William J. Bramlage
Department of Plant & Soil Sciences, University of Massachusetts
Very few apple storage operators in the North-
east give any consideration to humidity levels in the
storage. In part, this is because it is difficult to
measure humidity accurately when it is near 100%.
I do not know of any New England storage, except at
the University of Massachusetts Horticultural Re-
search Center in Belchertown, that is equipped to
measure storage humidity. Yet, humidity is an
important variable in determining the quality of
fruit after storage.
We are reminded of this by a recent report of
research by Dr. Perry Lidster, conducted at the
Agriculture Canada Research Station in Kentville,
Nova Scotia (J. Amer. Soc. Hort. Sci. 115:94-96,
1990). In this study, Mcintosh apples were stored in
either standard CA (3% 2 , 5% C0 2 , 37T), or in low-
oxygen CA (1% 2 , 0.5% C0 2 , 37T). In each atmos-
phere, relative humidity was maintained at 75%,
81%, 89%, 92-96%, or 96-100%. The total experi-
ment was repeated in two separate years.
Humidity influenced fruit quality after storage
in a number of ways. As you would expect, weight
loss increased as relative humidity fell, due to evapo-
ration of water from the fruit. For example, in
standard CA one year, fruit lost 4.4%, 2.7%, 2.5%,
1.0%, and 0.3% of their original weight during stor-
age at 75%, 81%,
89%, 92-96%, and
96-100% relative
humidity, respec-
tively. In addi-
tion, fruit lost
more firmness
during storage as
humidity was
reduced, and
these differences
were still meas-
urable after 7
days at room tem-
perature. Fruit
also were pro-
gressively less
permeable to
gases as humidity was reduced; low permeability
can interfere with normal respiration by fruit at CA
conditions.
The clearest effects of humidity during storage
were on the development of various disorders in the
fruit after storage (Table 1). It commonly is recom-
mended that apple storages be operated at 90-95%
relative humidity. Humidities lower than this did
not increase the occurrence of disorders in standard
CA, and in fact 75% lowered the amount of senescent
breakdown that occurred. (Similar results have
been reported before.) However, humidity at greater
than 95% increased senile brown core and senescent
breakdown. The effect on rotting was not statisti-
cally significant, but there tended to be more rot with
very high humidity. These results are consistent
with those in earlier studies, indicating that very
high humidity encourages senescent disorders in
apples.
However, in low oxygen storage, effects of
humidity on disorders were quite different from
those in standard CA (Table 1). Low humidities
clearly increased epidermal bluing and cortical
browning, both of which are symptoms of oxygen
deficiency. It is likely, therefore, that low humidity
caused greater occurrence of these disorders by
Table 1. Effects of humidity in standard CA and low oxygen CA on fruit disorders
after 7 days at room temperature following removal from storage.
Storage
humidity
(%)
Standard CA
Low-oxygen CA
Senile
brown core
(%)
Senescent
breakdown
(%)
Rot
(%)
Epidermal Cortical
bluing browning
(%) (%)
Rot
(%)
75
81
89
92-96
96-100
5
7
7
9
23
2
6
5
4
14
6
5
5
6
9
6 7
15 4
8 2
1 1
1 2
4
6
5
4
7
Fruit Notes, Winter, 1991
lowering gas permeability of the
fruit. Furthermore, the very
high humidity did not have an
adverse effect in low oxygen CA,
as it did in standard CA.
These results indicate that
the effects of humidity follow
several patterns. In terms of
fruit condition, humidity should
be kept as high as possible.
However, in terms of occurrence
of disorders, humidities above
95% are detrimental if senescent
disorders are a concern, as they
are in air storage or standard
CA. But if the storage is being
run as a low oxygen CA, the
threat is not senescent disorders
but ones due to disruption of
respiration, and here, humidity
as high as possible would be
beneficial.
In New England we have
had no success with low oxygen
CA and have never recom-
mended its use. Thus, humidity above 95% is not
desirable in our apple storages. We should be trying
to maintain about 92-95% relative humidity. Lower
levels cause loss of fruit condition and high levels
enhance senescent disorders.
What can a storage operator do to maintain
appropriate relative humidity? It cannot be con-
trolled because it is not even being measured! Yet,
basic procedures will provide reasonable assurance
that relative humidity is probably between 90 and
95%. Making sure that rooms and bins have ab-
sorbed ample water before loading avoids the prob-
lem of dry wood absorbing large quantities of water
from the air during storage. Placing water on the
floor provides an evaporating surface other than the
fruit. However, correct operation of the cooling
system is the most fundamental way to avoid inap-
propriate storage humidity, because the cooling coils
have a drying effect on the storage atmosphere by
causing ice to form on the coils (thereby taking water
from the air).
Table 2. Minimum relative humidity levels (%) developed at
various storage and evaporator discharge temperatures.
(From: Bartsch, J. A and G. D. Blanpied. 1984. Refrigeration
and Controlled Atmosphere Storage for Horticultural Crops.
NRAES-22, Cooperative Extension, Cornell University, Ithaca,
NY 14853.)
Temperature
drop*
Storage temperature (°F
1
across evaporator
(*F)
32*
35*
38'
-1
95.8
96.1
96.1
-2
91.2
92.3
92.4
-3
87.1
88.7
88.8
-4
83.0
84.7
85.3
-5
79.4
80.9
82.0
-10
62.7
64.1
65.3
-15
49.3
50.5
49.4
*Actual airstream temperature drop between inlet and outlet.
The coil temperature difference will be approximately twice
this value.
The minimum humidity level in the storage
atmosphere is determined primarily by the tempera-
ture difference ("split") between the evaporator inlet
and outlet. The effect of this "split" on relative
humidity in the room is shown in Table 2. The "split"
must be no more than 2* or 3* or humidity will be too
low. On the other hand, if it is 1* or less, humidity
may become high enough to enhance the occurrence
of senescent disorders.
It is often believed that "wet" coils (using a brine
spray defrost) produce higher humidity than do
"dry" coils. This is not true. In fact, "wet" coils often
produce lower humidities than "dry" coils, especially
at lower temperatures. What is important is not
whether coils are "wet" or "dry", but rather, the
temperature drop across the evaporator.
The effects of humidity in storage on apple
quality are often forgotten in the worries over tem-
perature and atmosphere, but as Lidster's data
clearly show, the humidity in the storage may have
much to do with the quality of the fruit when it is
taken from the storage.
Fruit Notes, Winter, 1991
Catfacing by Oak and Hickory Plant
Bugs in Massachusetts Peach Orchards
Kathleen P. Leahy
Department of Entomology, University of Massachusetts
Although there are several types of damaging
insects present in local peach orchards, including
borers, aphids, and Oriental fruit moth, most grow-
ers in Massachusetts are concerned primarily with
the complex of insects which cause feeding scars, or
catfacing, on the surface of the fruit. The traditional
"most wanted list" of catfacing insects includes the
tarnished plant bug, plum curculio, and three spe-
cies of stink bug: green, dusky, and brown.
Recently, attention has been focused on the
catfacing activity of three species of the genus Ly-
gocoris: the white oak plant bug (L. quercalbae), the
hickory plant bug (L. caryae), and L. omnivagus
(which does not have a common name). The three
species are very similar in appearance and have
sometimes collectively been called "oak-hickory"
plant bugs. The genus is closely related to the genus
Lygus that includes the tarnished plant bug, and
they look quite similar to the tarnished plant bug
except that they lack the characteristic markings on
the scutellum and the "tarnished" or shiny appear-
ance, and look a little less sturdy. They are usually
brown to brownish-yellow. See Figure 1.
These plant bugs were cited frequently in the
literature in the 1920s and 1930s as causing cat-
facing injury to peaches, but received little attention
between that time and the 1980s. Since they have
not been well studied as peach pests, and are not
considered pests in the forests where they spend
most of their life cycle, apparently little is known
about them.
All three species spend most of their lives on host
trees in the woods - oak, hickory, chestnut, dogwood,
black walnut, beech, and several other tree species.
As adults, they disperse from their native hosts,
during which time they may move through peach
orchards. This flight usually begins in early June, a
few weeks after peach shuck split, and generally
peaks in mid-June, decreasing considerably in July.
They do not appear to reside within peach orchards,
but only visit them briefly and feed in a "hit-and-run"
fashion, which may make them difficult to control.
Tarnished plant bug injury generally occurs
close to petal fall, and usually causes fruit drop.
Lygocoris feeding occurs later and usually causes
catfacing: sunken, scabby, often oozing scars on the
surface of the fruit. Damage caused by plum curculio
is similar to that caused by the Lygocoris bugs.
Research was done by Vanessa LeFebrve and
Roger Adams in Connecticut in 1981 and 1982 focus-
ing on methods to monitor these insects. Visual
traps were found to be more effective than sweep
nets or visual inspection. Like tarnished plant bugs,
the Lygocoris bugs appear to be "visual generalists"
and were attracted to several of the colors used in the
study. The most consistent results were achieved
using a peach blossom mimic, Pittsburgh Paint
"Pink Tiara." Traps placed high in the tree canopy
and with a vertical orientation, were highly effective
compared to traps placed low in the tree canopy, or
with a horizontal orientation. This result reflects
the fact that Lygocoris bugs fly in from the woods and
do not reside in the ground cover like tarnished plant
bugs. Traps placed in the woods bordering the
orchards also caught high numbers of these bugs.
Variability was high, but there appeared to be fairly
good correlation between trap captures, both in the
orchard and in the woods border, and fruit damage.
Last summer we did a preliminary trial to see
whether any of the three species could be caught in
Massachusetts peach orchards. Rather than spend
time on further testing of traps, colors, and orienta-
tions, we used the combination that seemed most
successful in the Connecticut study: the "pink tiara"-
colored traps, hung vertically high in the canopy.
Traps were also hung in the woods around the
orchard, primarily on tree species known to harbor
Lygocoris. Four peach blocks were monitored, two of
which had very little crop due to the spring freeze.
We could not gather sufficient data to develop corre-
lations between trap captures and injury to peaches.
Generally, however, growers reported seeing cat-
facing very close to the time when bugs were cap-
tured.
Traps in the orchards and in the woods caught
all three species of Lygocoris bugs, with L. omni-
vagus predominating slightly. There did not appear
to be a relationship between species captured and
Fruit Notes, Winter, 1991
Figure 1. Plant bugs of potential importance in Massachusetts peach orchards: (A) white oak plant
bug (Lygocoris quercalbae); (B) hickory plant bug (L. caryae); (C) L. omnivagus; and (D) tarnished
plant bug (Lygus lineolaris). A, B, and C from Kelton, L. A. 1971. Review ofLygocoris species found
in Canada and Alaska (Heteroptera: Miridae). Mem. Entomol. Soc. Canada 83. 87 pp. D from
Metcalf, R. L. 1962. Destructive and Useful Insects. McGraw-Hill.
woods composition, and the bugs had no apparent
trouble reaching blocks that were well away from
the woods. For this reason, it does not appear that
manipulating the borders of peach blocks would
have much impact on catfacing activity. In addition,
only the white oak plant bug is reported to have a
strong host preference; the other two, especially L.
omnivagus, occur on so many species it would be
impossible to eliminate all alternate hosts.
Some logistic problems were noted that might be
of interest to anyone wishing to use the visual traps.
The traps consisted of cardboard leafminer traps
repainted with a water-based paint and coated with
Tangle-trap. Because of the length of time these
traps were in the field (mid-May to July or later), the
cardboard was not adequate, and the traps weath-
ered severely. A sturdier material would be better -
wood or plastic (now used for the commercial
leafminer traps, but do no use those with the pre-
stickied surface, however!). The water-based paint
did not hold up well under the Tangle-trap, espe-
cially if two traps were placed together and then
pulled apart. Finally, the trap was often quickly
obscured by the canopy of the tree, since both the
traps and the leaves have a tendency to droop. A
better arrangement would be to hang the trap on a
post of some sort, on which it could be slightly above
the level of the peach tree foliage.
One surprising observation was that these plant
bugs also frequently were found on the baited red
sticky spheres hung in apple orchards to trap apple
maggot flies. Whether it was the color, shape, or odor
of the trap may be worth investigating. If they can
be lured to traps with an odor bait, then perhaps it
would be possible to trap them out.
We have established that all three species of
Fruit Notes, Winter, 1991
catfacing Lygocoris bugs are present in Massachu-
setts peach orchards, that they appear to be at-
tracted to pink traps hung high in the canopy, and
that there may be a relationship between increased
trap captures and catfacing activity. Many ques-
tions remain, however. First, are these bugs actu-
ally the major culprit in peach catfacing, and can
other insects, particularly tarnished plant bug, be
regarded as negligible problems? Next, do trap
captures truly reflect the level of activity in the field;
can we establish an action threshold; and will this
method give growers enough time to take action, or
has the damage already been done by the time the
bugs appear on the traps? The Connecticut research
indicated that there seemed to be a closer correlation
between trap capture and fruit injury at higher trap
capture levels, which seems to hint that economic
action thresholds may be appropriate. They also
reported that damage in the field sometimes oc-
curred before, or simultaneously with, the increased
trap captures. Other trap designs should be inves-
tigated for more effective monitoring, or even for
trapping out these insects. At present, most growers
in Massachusetts use a minimal spray program on
their peaches. We would like to achieve better
control of catfacing insects without causing an in-
crease in pesticide use.
Further Reading on Plant Bugs
in Peaches
Caesar, L. 1921. Notes on leaf bugs (Miridae) attack-
ing fruit trees in Ontario. Entomol. Soc. Ont. Annu.
Rep. 51 (1920):14-16
Chandler, S.C. 1955. Biological studies of peach
catfacing insects in Illinois. J. Econ. Entomol.
48(4):473-475.
Kelton.L.A 1971. Review otLygocoris species found
in Canada and Alaska (Heteroptera: Miridae). Mem.
Entomol. Soc. Canada 83. 87pp.
LeFevre, V.F. 1984. Development of Monitoring
Techniques for Plant Bugs (Hemiptera: Miridae)
That Cause Catfacing Damage to Peaches in Con-
necticut. Masters Thesis, University of Connecticut.
Prokopy, R.J., R.G. Adams, and K.I. Hauschild.
1977. Visual responses of tarnished plant bug adults
on apple. Environ. Entomol. 64(6):202-205.
Rings, R.W. 1957. Types and seasonal incidence of
plant bug injury to peaches. J. Econ. Entomol.
51(l):27-32.
Ross, W.A. and L. Caesar. 1927. Oak and hickory
plant bugs. 58th Ann. Rpt. Entomol. Soc. Ont.:\l.
Woodside, AM. 1946. Cat-facing and dimpling in
peaches. J. Econ. Entomol. 39(2):158-161.
Fruit Notes, Winter, 1991
Evaluation of Amblyseius fallacis
Predatory Mites on Apple Trees One
Year After Their Release
Margaret M. Christie, Ronald J. Prokopy, James Gamble,
David Heckscher, and Jennifer Mason
Department of Entomology, University of Massachusetts
Last year we reported results of two years of
releases of the predatory mite Amblyseius fallacis in
first- and second-stage IPM blocks [Fruit Notes
55(1):12-16]. These demonstrated that effective
biocontrol is more likely with a release of about
67,500 adult A fallacis per acre than with a release
of only 22,500 adults per acre. In 1990, we examined
the ability of previously released A fallacis to over-
winter and provide control of pest mites in the first
year following release. To reduce the expense of
releasing tens of thousands of A. fallacis per acre, we
hoped that treatment would not need to be repeated
each year to achieve effective control.
Methods
During 1988 and 1989, we released predatory A.
fallacis in 2 blocks in each of 4 orchards. One block
was managed using first-stage IPM methods, apply-
ing pesticides based on the results of monitoring for
pests and predators. The second block was managed
according to transitional second-stage IPM prin-
ciples [Fruit Notes 55(1):9-12]. No insecticides or
miticides were applied to the interior of this block
after the final plum curculio spray in early June.
Border row sprays of Guthion™ or Imidan™ were
used every three weeks to control apple maggot fly,
and fungicides harsh to predatory mites (such as
mancozeb and benomyl) were avoided.
In 1988, we released approximately 500 adult A.
fallacis beneath each of 7 trees in both first- and
second-stage blocks in the 4 orchards. In 1989, we
released approximately 1500 A. fallacis adults in the
foliage of each of 7 trees in the first and second stage
blocks. Predators were released when 20 to 40% of
the leaves in the first- and second-stage blocks were
infested with European red mites or two-spotted
mites. Sampling for pest and predatory mites took
place in June (before releases of predatory mites), in
July (shortly after A fallacis had been released), in
August, and in September.
In 1990, first-stage IPM management continued
in one block in each orchard. In the second-stage
IPM block, border row sprays for apple maggot fly
during July and August were replaced with sticky
red sphere traps placed around the perimeter of the
block. No mite predator releases were made in any
of the blocks. Sampling again occurred in June,
July, August, and September.
Additionally, we monitored pest and predatory
mite levels in first- and second-stage blocks in 4
orchards each year which had not received A falla-
cis releases. In the second-stage blocks in these
orchards, sticky red sphere traps were used for AMF
control; no insecticide or miticide was applied to the
blocks after early June in any year.
Results
In the 4 orchards in which releases of A fallacis
occurred in both 1988 and 1989 (Table 1), the ratio of
pest mites to predatory mites averaged 8: 1 in second-
stage blocks and 9:1 in first-stage blocks after release
in 1988, suggesting that only moderate biocontrol of
mites could be expected. By late June of 1989, pest
mites had almost reached threshold levels for treat-
ment, and no A fallacis had been found. After
release of A fallacis in July of 1989, the ratio of pest
to predatory mites averaged 4:1. In September the
ratio of pest mites to A. fallacis was 2:1 in the second-
stage blocks and 1:1 in the first-stage blocks. These
ratios were highly favorable to biological control of
pest mites. During 1990, pest mite levels in these
orchards began to increase in July; by August, they
reached 46% of sampled leaves in second-stage
blocks and 36% of leaves sampled in first-stage
blocks. Despite their high levels at the end of the
1989 growing season, very few A fallacis were found
until late 1990. Not until September, after danger of
mite damage had passed, did the ratio of pest mites
10
Fruit Notes, Winter, 1991
Table 1.
Results in
4 orchards where A. fallacis were released in 1988 and 1989.
Percent of sampled
leaves with*
Ratio of pest
Time of
ERM +
mites to
Year
sampling
Block type
TSM AF
A fallacis
1989
July
Second-stage
69 4.8
14:1
First-stage
55 3.0
18:1
August
Second-stage
51 15.3
3:1
First-stage
32 11.4
3:1
Sept.
Second-stage
25 13.6
2:1
First-stage
8 11.5
1:1
3 month
Second-stage
48 11.2
4:1
average
First-stage
32 8.6
4:1
1990
July
Second-stage
25 0.3
84:1
First-stage
20 0.0
20:0
August
Second-stage
46 0.8
57:1
First-stage
36 3.8
9:1
Sept.
Second-stage
71 14.0
5:1
First-stage
71 5.3
13:1
3 month
Second-stage
47 5.0
9:1
average
First-stage
42 3.0
14:1
*On each date in 1989, we sampled 10 leaves per tree on 14 trees per block (7 under which
A fallacis were released and 7 adjacent trees)
In 1990, we sampled 10 leaves per tree on
10 trees
per block.
ERM = European red mite; TSM = two-spotted mite;
AF = A fallacis.
to A fallacis fall to 5:1 in the second-stage blocks.
From July to September, the ratio of pest mites to A.
fallacis averaged 9:1 in the second-stage blocks
versus 14:1 in the first-stage blocks (Table 1).
In the 4 orchards which did not receive A falla-
cis releases (Table 2), the ratio of pest mites to A.
fallacis in 1989 averaged 6:1 in second-stage blocks
and 13:1 in first-stage blocks in July, August, and
September. In 1990, the ratio of pest mites to A.
fallacis averaged 7:1 in the second-stage blocks and
6:1 in the first-stage blocks in July, August, and
September. A fallacis levels were slow to build,
however, allowing pest mite levels to reach 38% in
second-stage blocks and 33% in first-stage blocks in
August.
Conclusions
Our results during the three years of this study
indicate that release of A fallacis predatory mites
cannot be counted on to provide ongoing pest mite
control. It may be that the particularly cold weather
in December of 1989, accompanied by lack of snow
cover, adversely affected the overwintering of A.
fallacis. Another possibility is that the predatory
mites released are not completely resistant to or-
ganophosphate pesticides. Yet another possibility is
that predatory mites that had built to high numbers
in blocks in which they were released in 1989 moved
out of these blocks in April and May, 1990, when pest
mites were perhaps too few in number to support
predators. Whichever, the finding in 1990 that the
ratio of pest mites to A fallacis was essentially no
different in second-stage IPM blocks where A falla-
cis were released in large numbers in 1988 and 1989
and in second-stage IPM blocks where A fallacis
had never been released, calls into question the
value of releasing predatory A fallacis in apple
orchards until further research is conducted.
In 1991, we plan again to release predatory
Fruit Notes, Winter, 1991
11
Table 2.
Results in 4 orchards where
no A fallacis were released.
Percent of sampled
leaves with*
Ratio of pest
Time of
ERM +
mites to
Year
sampling
Block type
TSM AF
A fallacis
1989
July
Second-stage
17 0.0
17:1
First-stage
34 0.0
34:0
August
Second-stage
36 2.3
16:1
First-stage
65 2.3
28:1
Sept.
Second-stage
23 10.8
2:1
First-stage
23 0.8
31:1
3 month
Second-stage
25 4.4
6:1
average
First- stage
41 3.1
13:1
1990
July
Second-stage
17 0.5
35:1
First-stage
28 0.0
28:0
August
Second-stage
38 5.8
7:1
First-stage
33 5.0
7:1
Sept.
Second-stage
35 6.0
6:1
First-stage
16 7.0
2:1
3 month
Second-stage
30 4.1
7:1
average
First-stage
26 4.0
6:1
*On each sampling date each year, we sampled 10 leaves per tree on 10 trees per block. ERM
= European red mite
TSM = two-spotted mite; AF = A fallacis.
mites if pest mite levels warrant treatment. Through
continuing study, we may be able to determine if we
can predict some pest mite control by A fallacis the
followingyear. Prediction could be based on weather
conditions, pest to predator ratios in September,
groundcover composition, or some other variable.
Our results to date, however, indicate that the pros-
pects are not strong for continuous biological control
of pest mites from one year to the next following a
single release of A fallacis predators.
Acknowledgements
The work in 1990 was supported principally by
a grant to study biological control of apple orchard
pests from the Massachusetts Department of Food
and Agriculture. We thank the participating grow-
ers for their cooperation: Bruce Carlson, Dave
Chandler, Dave Cheney, Tony Lincoln, Harvey and
Marvin Peck, Wayne and Jesse Rice, Steve
Smedberg, and Maurice Tougas.
From: Thomm. J.J. 1906. The American Fruit
Culturist. Orange Judd Company, New York.
12
Fruit Notes, Winter, 1991
Hunting Spiders in Second-stage
IPM Apple Orchard Blocks
Ronald J. Prokopy, Margaret M. Christie, James Gamble,
David Heckscher, and Jennifer Mason
Department of Entomology, University of Massachusetts
As pointed out in a recent review by Nyfeler and
Berg (1987), spiders are among the most abundant
predators of insects in terrestrial ecosystems. There
are 2 principal kinds of spiders. One kind builds
webs, such as web-weaving and funnel web spiders.
In some natural grassland communities, web-build-
ing spiders have been estimated to capture an aver-
age of 200,000 insects per acre per day, thereby
exerting a strong degree of biological pest control.
The other kind of spider does not build webs but
instead hunts for prey. These include jumping
spiders and wolf spiders. These too can have a
powerful biological control effect in undisturbed
habitats.
Over the past 2 decades or so, fairly extensive
surveys of spider populations have been undertaken
in commercial and abandoned apple orchards in
several regions of North America (Dondale et al.,
1979; McCaffrey and Horsburgh, 1980; Bostonian et
al., 1984). Not surprisingly, the general conclusion
is that spiders, particularly hunting spiders, are con-
siderably more abundant in unsprayed than sprayed
orchards. Unfortunately, outside of laboratory stud-
ies under artificial conditions, little is known about
the kind of prey consumed by spiders in orchards.
Suspected prey include aphids, leafroller moths and
larvae, leafhoppers, thrips, mites, and even benefi-
cial insects such as lacewings and ladybird beetles.
As a first step toward acquiring
better knowledge of the potential
role of spiders as biological pest
control agents in Massachusetts
apple orchards, in 1990 we com-
pared the relative abundance of
hunting spiders in 12 blocks of com-
mercial apple trees (2 to 3 acres
each) that received no insecticide
after early June under full second-
stage IPM practices [Fruit Notes
55(l):4-9] with abundance in 12 ad-
jacent blocks that received 2 to 3 in-
secticide sprays after early June
under normal first-stage IPM practices. To estimate
spider abundance in each block in early August and
again in early September, we tapped 3 branches on
each of 10 trees per block to dislodge hunting spiders,
which fell onto a framed cloth (2x2 feet) held
beneath the branch.
The results (Table 1) show that in early August,
hunting spiders were slightly but not significantly
more abundant in second-stage than first-stage IPM
blocks. By early September, hunting spiders had
more than tripled in abundance in the second-stage
IPM blocks and were more than double the number
there compared with first-stage IPM blocks.
Thus, like mite predators and leafminer parasi-
toids [Fruit Notes 55(l):4-9], hunting spiders may
build to higher populations in Massachusetts apple
orchard blocks free of insecticide spray after early
June compared with blocks receiving insecticide in
July and August. We do not know the principal type
of prey consumed by spiders on the trees that we
sampled. We believe, however, that the prey may
have included summer leafroller larvae and leafhop-
pers. Hence, we plan in the future to explore in
depth the effectiveness of spiders as predators of
leafroller larvae and leafhoppers and the role of
orchard understory cover in promoting buildup of
not only mite predators but also of spiders.
Table 1. Average number of sampled hunting spiders per
orchard block.
Time of sampling
Second-stage
IPM blocks
First-stage
IPM blocks
Early August
Early September
2.6 a*
8.6 a
2.1a
3.9 b
*Values within the same row followed by a different letter
are significantly different at odds of 19:1.
Fruit Notes, Winter, 1991
13
Acknowledgements
This work was supported principally by a grant
to study biological control of apple orchard pests
from the Massachusetts Department of Food and
Agriculture. We thank the participating growers for
their cooperation: Bill Broderick, Bruce Carlson,
Dave Chandler, Dave Cheney, Tony Lincoln, Dave
Lynch, Harvey and Marvin Peck, Wayne and Jesse
Rice, Bill Rose, Tony Rossi, Steve Smedberg, and
Maurice Tougas.
References
Bostonian, N.J., Dondale, CD., Binns, M.R., and
Pitre, D. 1984. Effects of pesticide use on spiders in
Quebec apple orchards. Can. Entomol. 116:663-675.
Dondale, CD, Parent, B., and Pitre, D. 1979. A 6-
year study of spiders in a Quebec apple orchard.
Can. Entomol. 111:377-380.
McCaffrey, J.P. and R.L Horsburgh. 1980. The
spider fauna of apple trees in Central Virginia.
Environ. Entomol. 9:247-252.
Nyfeler, M. and Berry, G. 1987. Spiders in natural
pest control: a review. J. Applied Entomol. 103:321-
339.
fnm. IVaai. J. J. IBM Tkt Anrnwi ftiwt
Massachusetts Apple IPM Program
Observations in 1990
Kathleen P. Leahy and William M. Coli
Department of Entomology, University of Massachusetts
Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Insect and Disease Situation
Scab: The most notable form of injury at harvest
was apple scab. Growers who timed their sprays
well and had a good understanding of the use of
sterol-inhibiting (SI) fungicides had little problem
with scab; however, growers who "played games"
with the Sis had serious problems. Clearly, the pres-
sure was intense during part of the primary scab
season, resulting in high levels of injury where trees
were not protected. Interestingly, one grower used
3 SI + protectant applications beginning at bloom
and his fruit had no injury at harvest.
Apple Maggot Fly: Generally, insect problems
were insignificant this year, but apple maggot fly
was present in fairly large numbers through most of
August and September, resulting in the need for 2 to
4 half-rate insecticide applications. Injury from
apple maggot fly was noted in some low-spray and
no-spray blocks.
Leafminer: An extraordinarily large emergence of
leafminer adults occurred in many orchards this
spring; however, it resulted in little or no egglaying
in the first generation. In the few cases where mines
were present in substantial numbers, they seemed to
be concentrated on the same age cluster leaf, and
were extremely localized within the orchard. Per-
haps the high winds during the time when adults
were flying prevented significant egglaying. Popu-
lations did build up again over the course of the
season, but did not reach damaging levels in the
second or third generation in most orchards.
Tarnished Plant Bug, European Apple Sawfly,
Plum Curculio: These early-season fruit-injuring
insects were at very low levels, and injury at harvest
was not significant. Many growers were able elimi-
nate their pre-bloom insecticide application and also
14
Fruit Notes, Winter, 1991
to delay petal-fall applications for up to 2 weeks. The
cool, windy spring weather was probably the reason
for the low activity of these insects.
Sooty Blotch, Flyspeck: A non-commercial dem-
onstration block that received no fungicide after
primary scab season showed about 30% flyspeck at
harvest. Commercial orchards showed little or no
sooty blotch or flyspeck, indicating that spray pro-
grams were controlling infections adequately.
Summer pruning reduced the incidence of sooty
blotch and flyspeck.
Fire Blight: In response to an exceptionally high
level of fire blight last season, we used Paul Steiner's
Maryblyte fire blight-forecasting computer program
this season. The program predicted that fire blight
infection potential was low to moderate in many
areas, but predicted outbreaks in the northeast-
central area (Harvard, Groton, Stow). Events oc-
curred very close to the timing predicted by the
Maryblyte model. Very little uncontrolled fire blight
was seen this year.
Mites: Growers who used one or two dilute dormant
oil sprays had very little trouble with mites this
season. Amblyseius fallacis mite predators were
found in many locations where mites began to build
up. Blocks on the monitoring program received an
average of 1.2 miticides during the summer. One
large orchard went without a miticide application
after the dormant oil spray.
Leafhoppers: Both white apple and potato leafhop-
pers were present in some orchards this year.
Damage to terminal growth by potato leafhopper
was evident in a few young orchards, although such
damage was far less widespread than several years
ago when it was first noted in the state.
Comments
As usual, the weather this year was unusual.
The cool, windy weather in the spring appeared to
hold back the usual onslaught of insect pests, par-
ticularly leafminer and plum curculio. Bloom was
prolonged (2 to 3 weeks). Bee activity was low due to
Table 1. Harvest injury in
blocks (5400 fruit surveyed
IPM monitoring
in 6 orchards).
Problem
Percent
damaged
Diseases
Apple scab
Black rot
Blossom end rot
Sooty blotch/fly speck
5.4
0.1
0.0
0.0
Total diseases
5.5
Insects
Plant bug
Leaf roller
Apple maggot
Sawfly
Plum curculio
Green fruit worm
0.7
0.1
0.0
0.2
0.2
0.0
Total insects
1.2
the windy, cool, and wet conditions, and fruit set was
less than optimal in many orchards. The time for
scab infections appears to have been relatively short
and very intense. A shortage of alternate host plants
may have contributed to the high level of apple
maggot fly this summer.
Acknowledgements
Our thanks to the following growers who partici-
pated in the IPM monitoring program this year:
Tony Lincoln, Bill Rose, Tony Rossi, Steve
Smedberg, Tim Smith, and Denis Wagner. We
would also like to thank Mrs. Victor Lutnicki for
allowing us to use her orchard to demonstrate low-
input techniques, and Jim Williams for overseeing
the Lutnicki orchard and providing information for
the Pest Alert messages.
Mam
nf^4^f^
Prom: Thomai, J.J. 1906. The American Fruit
Cuiturist. Orange Judd Company, New York.
Fruit Notes, Winter, 1991
15
Non-pesticidal Control of Summer
Codling Moths Through Habitat
Management
Ronald J. Prokopy, Margaret M. Christie, James Gamble,
David Heckscher, and Jennifer Mason
Department of Entomology, University of Massachusetts
Worldwide, codling moth continues to be the
most damaging of all pests of apple fruit. One reason
for this situation is the essentially universal distri-
bution of codling moth. It attacks apples on every
continent where apples are grown. In contrast, pests
such as apple maggot and plum curculio remain
confined to North America. Another reason why
codling moth is such a pest on a worldwide basis lies
in the multiple number of generations per year that
it can undergo. Here in the northeastern USA we are
fortunate in that there exist only 2 generations each
year. In the western USA, there exist at least 3
generations. In some other regions, for example
parts of Australia, there may be 4 or more genera-
tions per year. If there were 20 larvae in an aban-
doned orchard in the first generation, there might be
200 in the second generation. But if you had a third
generation, there might be 2000. A fourth genera-
tion might peak at 20,000.
Even at only 2 generations per year, codling
moth was a devastating insect in many commercial
orchards in New England before the advent of syn-
thetic pesticides in the late 1940s. Since then, it has
acquired the status of a relatively minor pest. It has
not, however, lost its ability to injure large amounts
of fruit on unsprayed trees. For example, on several
unmanaged apple trees 600 to 800 feet from
Prokopy's small commercial orchard in Conway,
MA, second-generation codling moth larvae infested
48% of fruit sampled in September during 1985
through 1989 [Fruit Notes 55(4):9-14]. In our opin-
ion, highly effective control of codling moth in New
England commercial orchards over the past 4 dec-
ades has resulted fortuitously from use of organo-
phosphate sprays such as Guthion™ and Imidan™
that are directed primarily against plum curculio in
late May and early June (thereby controlling first
generation codling moth larvae) and against apple
maggot from mid-July to mid-August (thereby con-
trolling second-generation codling moth larvae).
With the advent of cultural, biological and be-
havioral methods as substitutes for using pesticides
after early June to control arthropods in second-
stage IPM orchards [Fruit Notes 55(l):4-9], a way is
potentially open for second-generation codling moth
adults to invade orchards in July and August and lay
eggs in an orchard atmosphere free of pesticide. Two
non-pesticidal approaches for codling moth control
are receiving much attention in regions where cod-
ling moth has 3 or more generations per year. One
approach involves applying, during summer
months, several sprays of a selective virus that kills
codling moth larvae but little else. The other ap-
proach involves permeating the atmosphere of the
orchard with synthetic female sex pheromone to
disrupt mating behavior. Both approaches show
much promise; however, both are expensive to
employ.
Based on work conducted in the 1950s by Theo-
dore Wildbolz, we have been evaluating a non-
pesticidal approach to managing second-generation
codling moths that involves neither use of virus nor
mating disruption pheromone but uses habitat
management. By releasing mated codling moth
females at varying distances from commercial or-
chards, Wildbolz determined it was unlikely under
Swiss conditions (similar to New England condi-
tions) that individual females would move more than
100 yards or so in search of egglaying sites. He
postulated, therefore, that removal of principal
types of unmanaged host trees of codlingmoth (apple
and pear) within 100 yards of the perimeter of
commercial orchard blocks might provide sufficient
isolation to preclude movement of second-genera-
tion females into the block.
In May of 1987, we removed all abandoned apple
and pear trees (average of 7 per orchard) within 100
yards of each of 6 commercial apple orchard blocks (2
to 3 acres each) that received no insecticide after
early June from 1987 through 1989. Of the 5400
16
Fruit Notes, Winter, 1991
fruit sampled at harvest in these 6 blocks from 1987
through 1989, none were injured by codling moth
[Fruit Notes 55(l):4-9]. These findings were quite
encouraging. We then asked ourselves whether 50
yards rather than 100 yards free of codling moth host
trees might provide sufficient barrier to preclude im-
migration of second-generation females.
In 1990, we evaluated codling moth injury in 6
commercial apple blocks (2 to 3 acres each) where
abandoned apple and pear trees had been removed
in 1988 at different distances from the block perime-
ter. All 6 blocks received 3 to 4 insecticide sprays
against plum curculio and other pests from April to
early June but no insecticide thereafter.
The results (Table 1) show that in 2 blocks where
no apple or pear trees had been removed from the
surrounding habitat, codling moth injury to fruit at
harvest averaged 15% on abandoned trees within
to 50 yards of the block and 0.44% on commercial
trees within the block. In 2 blocks where all unman-
aged apple and pear trees had been removed within
50 yards of the block, injury averaged 16% on aban-
doned trees within 50 to 100 yards of the block but 0%
Table 1. Codling moth injury (%) to fruit at harvest in (a) abandoned apple
trees, (b) commercial blocks that did not receive any insecticide after early
June, and (c) commercial blocks that received 2 to 3 applications of insecticide
against apple fly maggot in July and August, 1990.
on commercial trees within the block. Likewise,
there was no codling moth injury to commercial fruit
in blocks where all unmanaged apple and pear trees
within 100 yards of the block had been removed. In
blocks adjacent to each of these 6 test blocks, there
was no codling moth injury under conditions where
2 to 3 insecticide sprays had been applied against
apple maggot in July and August.
In conclusion, our findings from 1987 through
1990 show clearly that second-generation codling
moths can be controlled successfully in Massachu-
setts orchards by the habitat management tech-
nique of removing all abandoned apple and pear
trees within 100 yards of the orchard perimeter. Our
findings in 1990 suggest that abandoned host tree
removal within 50 yards of the perimeter may be just
as effective as within 100 yards, but that allowing
abandoned fruit trees to persist within 50 yards of
the perimeter is not effective. Success of this cul-
tural approach to managementof second-generation
codling moths depends on controlling the first gen-
eration in May and early June through pesticide
sprays applied primarily against plum curculio and
on picking up drops
after harvest to pre-
vent within-orchard
population buildup.
Distance between abandoned
and commercial blocks (yards)
Treatment
0-50
50-100
100+
Abandoned trees
Commercial trees
receiving no insecticide
after early June***
Commercial trees receiving
2-3 insecticides after
early June***
14.7*
0.4
0.0
16.4*
0.0
0.0
0.0
0.0
*Samples from 5 trees to 50 yards from orchard, 44 fruit per tree.
**Sample from 3 trees 50 to 100 yards from orchard, 21 fruit per tree.
***
Sample from 10 trees per block, 80 to 90 fruit per tree.
We thank the
Northeast Regional
Project in Integrated
Management of
Apple Pests (NE 156)
and the Northeast
Regional Low-Input
Sustainable Agricul-
tural Project for sup-
porting this work.
Our thanks also to
the participating
growers: BillBroder-
ick, Dave Cheney,
Wayne and Jesse
Rice, Tony Rossi,
Steve Smedberg, and
Maurice Tougas.
Prom: Thomai, J.J. 1906. The American Fruit
Culturist. Orange Judd Company, New York.
Fruit Notes, Winter, 1991
17
Effect of Distance Between Traps on
Interception of Apple Maggot Flies on
Perimeter Apple Trees
Margaret M. Christie, Ronald J. Prokopy, James Gamble,
David Heckscher, and Jennifer Mason
Department of Entomology, University of Massachusetts
Second-stage IPM methods for arthropod pest
control in apple orchards, in which no insecticide or
miticide is applied after the final plum curculio
spray, rely on use of sticky red traps to control apple
maggot flies (AMF). We previously reported on
three years of trials (1987-89) of second-stage IPM
methods in Massachusetts orchards [Fruit Notes
55(l):4-9]. In 1990, we evaluated slightly altered
approaches when employing traps to intercept
immigrating apple maggot flies. The results of these
trials in 10 apple orchard blocks are presented here.
In 1987, we began working in 2 blocks in each of
6 Massachusetts orchards. Each grower used sec-
ond-stage IPM methods in one block of 2 to 3 acres
and first-stage IPM methods in another block. In
late June, apple maggot traps were hung 10 yards
apart on perimeter apple trees of each second-stage
IPM block. One vial of butyl hexanoate, a synthetic
apple volatile, was placed near each trap. In Septem-
ber, we sampled 500 fruit in each block and found
that 1.6% of the fruit in the second-stage blocks and
0.4% in the first-stage blocks had AMF injury (Table
1).
In 1988 and 1989, we hung apple maggot traps 5
yards apart in perimeter row apple trees. Again, one
vial of butyl hexanoate was positioned near each
trap. Each year, we sampled 200 fruit per block in
September. In 1988, 1.0% of fruit in the second-stage
Table 1. Apple i
stage IPM.
maggot fly trap captures and fruit injury in blocks employing first- and second-
Distance
between traps
(yards)
Year
Number
of blocks
AMF captured
(number/block)
Fruit injured (%)*
2nd-stage
blocks
lst-stage
blocks
5
1988
1989
1990
6
6
1
3,021
3,191
1,781
1.0
0.3
0.7
0.2
0.3
0.7
Average
2,664
0.7
0.4
10
1987
1990
6
1
2,054
3,065
1.6
12.3
0.4
0.7
Average
2,560
3.1
0.4
20
1990
2
1,335
2.7
1.0
40
1990
5
580
2.9
0.1
*In September, we sampled 500 fruit
and 300 fruit per block in 1990.
per block ir
1987, 200 fruit per block in 1988 and 1989,
18
Fruit Notes, Winter, 1991
blocks and 0.2% in the first-stage blocks had AMF
damage. In 1989, 0.3% of the apples in both first- and
second-stage blocks showed AMF injury (Table 1).
Separate trials completed in 1989 indicated that a
maximum number of fly captures was achieved
when 2 vials of butyl hexanoate were placed 12
inches from the trap [Fruit Notes 54(4):18-19].
We were most encouraged by the results
achieved in 1988 and 1989. The only drawback to the
AMF traps is the cost and inconvenience involved in
coating them with sticky, hanging them in late June
each year, and cleaning them at least twice each
season. One method which might reduce these costs
is use of pesticide-coated spheres, an option which
we continue to explore [Fruit Notes 55(2): 17-20]. A
second method would be to decrease the number of
traps hung in each block. We hoped that using 2
vials of butyl hexanoate would increase fly captures
per trap and thus reduce the number of traps needed
for effective control.
In 1990, we hung each trap using 2 vials of butyl
hexanoate and reduced the number of traps in some
blocks. In 1 of the original 6 second-stage blocks, we
hung 60 traps at a distance of 5 yards around the
perimeter of the block. In another of the original 6
blocks, we positioned 30 traps 10 yards apart. In 2
other original blocks, we hung 15 traps 20 yards
apart. We also placed 8 traps 40 yards apart in 5
blocks which had been managed using transitional
second-stage IPM methods from 1987 through 1989
[Fruit Notes 55(1):9-12]. During that time, the
border rows of the 6 blocks had been treated every
three weeks in July and August with Imidan™ or
Guthion™ against AMF. The interior of the blocks
received no insecticide or miticide after early June.
Table 1 summarizes results of all 4 years of study
of the use of AMF traps in these orchards. Effective
control was achieved only when the traps were hung
at distances of 5 yards apart. Over 3 years (1988-90),
AMF injury in second-stage blocks where traps were
placed 5 yards apart, averaged 0.7%. In adjacent
first-stage IPM blocks, AMF injury averaged 0.4%.
In two years of trials (1987, 1990) of perimeter traps
placed 10 yards apart, AMF injury averaged 3. 1%.
In adjacent first-stage blocks, AMF injury averaged
0.4%. When traps were hung 20 yards apart in 1990,
injury was 2.7% in the second-stage blocks vs. 1.0%
in the first-stage blocks. In the 5 blocks which had
traps 40 yards apart in 1990, injury averaged 2.9%
vs. 0.1% in the adjacent first-stage blocks.
Our results suggest that using additional butyl
hexanoate will not increase fly captures per trap
sufficiently to allow a reduction in the distance
between traps. In fact, we believe that the additional
apple scent might have attracted greater numbers of
flies to some orchards. Placing traps 5 yards apart,
however, continues to provide control comparable to
the use of first-stage IPM methods in small blocks.
In 1991, we plan to test the effectiveness of AMF
traps positioned with one vial of butyl hexanoate 5
yards apart around the perimeter of larger, 5 to 10
acre blocks.
Acknowledgements
We thank the Northeast Regional Project on
Integrated Management of Apple Pests (NE 156)
and the Northeast Regional Low-Input Sustainable
Agricultural Project for supporting this work. We
also thank the participating growers: Bill Broder-
ick, Bruce Carlson, Dave Chandler, Dave Cheney,
Tony Lincoln, Dave Lynch, Harvey and Marvin
Peck, Wayne and Jesse Rice, Bill Rose, Tony Rossi,
Steve Smedberg, and Maurice Tougas.
Fruit Notes, Winter, 1991
19
Strawberry Cultivar Screen for
Tolerance to Black Root Rot
Disease Complex
David Marchant, Daniel R. Cooley, Sonia G. Schloeman, and
William J. Manning
Department of Plant Pathology, University of Massachusetts
Black root rot is a disease complex of strawberry
that reduces vigor of the root system, resulting in
decreased productivity and longevity of a straw-
berry planting. Disease pressure can reach levels
where new plantings can be lost totally. Common
symptoms are blackening of the structural roots and
death of feeder roots. The disease complex does not
have a specific cause, but usually results from inter-
action of pathogenic fungi, root-lesion nematodes,
and stressful environmental conditions. Binucleate
Rhizoctonia spp. have been demonstrated as com-
mon causal fungi, as well as the nematode Praty-
lenchus penetrans (Husain and McKeen, 1963;
Martin, 1988; Townshend, 1962). The disease may
be confused with red stele, a disease caused by the
fungus Phytophthora. Black root rot lesions on
roots are typically brownish to black in color, and
they destroy the cortex, or outer layers, of the root.
While early red stele may blacken root tips, fully de-
veloped red stele has the typical brick red stele in the
center of infected roots. Red stele generally occurs
on wet sites, while black root rot may be less likely on
a wet site. Cultivar sensitivity for red stele is well-
understood; however, little work has been done on
cultivar variation in sensitivity to black root rot.
In 1990, a cultivar screening test for resistance
Table 1. Effect of inoculation with multinucleate Rhizoctonia AG-KB-43) on the
survival and growth of ten strawberry cultivars.
Decrease in growth
Survival (%)
caused by
Growth/
Rizoctonia spp.
survival
Cultivar
Inoc.
Non-inoc.
(%)
index
Jewel
64 a'
86 a
34 ns*
390 c
Earliglow
60 a
96 a
29 ns
1090 be
Allstar
58 a
60 b
38 ns
90 c
Surecrop
56 a
88 a
30 ns
1030 be
Blomidon
52 ab
90 a
43 ns
2460 be
Honeyoye
42 abc
92 a
54 *
3570 ab
Kent
36 abc
74 ab
47 *
1150 be
Lester
24 be
92 a
70 *
5300 a
Red Chief
24 be
84 a
27 ns
1340 be
Midway
16 c
78 ab
13 ns
1440 be
'Means within
jach column
not followed by the same letter are
significantly
different at odds of 19:1.
"Inoculated and
non-inoculated means for each cultivar were tested for signifi-
cant differences
ns=no signi
Eicant difference between the non-inoculated and
inoculated, and '
*' indicates significance at odds of 19:1.
20
Fruit Notes, Winter, 1991
to Rhizoctonia spp. was planted at the University of
Massachusetts research farm in S. Deerfield, MA.
Ten strawberry cultivars commonly grown in north-
eastern North America were planted on July 3. Plots
had 20 plants and were replicated 5 times. Individ-
ual plots were split, with half of each plot inoculated
with multi-nucleate Khizoctonia spp. AG-KB-43).
Inoculation was performed by adding to each plant-
ing hole 25 ml of oat seed that had been cultured with
the Rhizoctonia isolate. Plants were harvested with
full root systems the first week of October. Charac-
teristics evaluated included plant survival, vegeta-
tive growth, root length, and injury to roots.
In the Rhizoctonia-inoculated plots, 'Jewel,'
'Earliglo,' 'Surecrop,' and 'Allstar' survived signifi-
cantly better than 'Lester,' 'Midway,' and 'Red Chief
(Table 1). Plant growth, as measured by dry weight,
was significantly different between cultivars in both
inoculated and control plots; however, in order to
estimate the effect of the Rhizoctonia, the percent
differences between inoculated and non-inoculated
plants must be considered. The only cultivars that
showed significantly poorer growth under the inocu-
lated regime were 'Honeyoye,' 'Kent,' and 'Lester.'
An index of injury was computed to combine both
the effects of Rhizoctonia on plant survival and
growth. The difference in survival (inoculated vs.
non-inoculated) was multiplied by the percent dif-
ference in dry weight (inoculated vs. non-inocu-
lated). The smaller the index, the better the plant
performed under Rhizoctonia inoculation. Using
this index, 'Allstar' performed well, and 'Lester" did
poorly.
This trial was done under artificial conditions,
but it indicated that 'Lester* is more susceptible to
this strain of Rhizoctonia than a cultivar like 'All-
star.' However, there is much to learn about the re-
lationships of these resultsto black root rot toler-
ance.
Future work will concentrate on a multi-year
study with low concentration inoculations of
Rhizoctonia spp., including evaluations of plant
vigor and fruit production.
References
Husain, S.S. and W. E. McKeen. 1963. Rhizoctonia
fragariae sp. nov. in relation to strawberry degen-
eration in southwestern Ontario. Phytopathology
53:532-540.
Martin, S.B. 1988. Identification, isolation fre-
quency, and pathogenicity of anastomosis groups of
binucleate Rhizoctonia spp. from strawberry roots.
Phytopathology 78:379-384.
Townshend, J.L. 1962. The root lesion nematode,
Pratylenchus penetrans (Cobb 1917) Filip & Stek,
1941 in strawberry in the Niagara Peninsula and
Norfolk County in Can. J. Plant Sci. 42:728-736.
From Fleuher, 8. w 1917
StnMtb4rry-Gfowutg. MafMillan,
KnVaL
Fruit Notes, Winter, 1991
21
Effects of Sulfur and Copper Fungicid
on Fruit Finish, Scab, and Soil Acidity
Daniel R. Cooley, James W. Gamble, and Mark Mazzola
Department of Plant Pathology, University of Massachusetts
Sulfur and copper have been used for over 100
years in commercial apple orchards as broad spec-
trum fungicides. More recently, these chemicals
have been used by growers seeking an 'organic' or
low-input approach to disease management. To de-
termine how effective sulfur or lime sulfur and early-
season copper applications are in controlling apple
scab, 12-year-old scab-susceptible apple trees on M.7
rootstock were treated with different combinations
of sulfur and copper fungicides starting at half-inch
green.
The experimental block had unusually high scab
inoculum. Treatments were applied to 5 cultivars,
'Mcintosh,' 'Empire,' 'Golden Delicious,' 'Delicious,'
and 'Cortland.' Primary scab treatments were ap-
plied on the following dates: April 20, 26, May 3, 11,
18, 25, and June 1. The first application was made
at the half-inch green growth stage, and according to
ascospore maturity evaluations, a significant
amount of inoculum had been released in an infec-
tion period the previous week. Summer cover treat-
ments were applied on June 15, 29, and July 13.
Treatments were the following:
1. lime sulfur @ 2 gal/lOOgal;
2. lime sulfur @ 2 gal/100gal+ copper (Kocide 101™)
@ 41bs/100gal;
3. sulfur (95WP) @ 5 lbs/lOOgal + copper @ 41bs/
lOOgal;
4. captan (50WP) @ 21bs/100gal.;
5. an untreated control
Treatments which included copper were applied
as copper only on the first spray date (April 20; trees
in half-inch green), and as sulfur or lime sulfur alone
thereafter. A dormant oil application (2 gal/100) was
made on April 27 to all trees.
All treatments were sprayed to runoff using a
handgun at approximately 200 psi with a base rate
of 300 gal/acre, and approximately 2 gal/tree. For
the 3 secondary scab applications, all sulfur and lime
sulfur treatments were sprayed with sulfur 95WP at
5 lb/100 gal , while the captan treatment was contin-
ued at 2 lbs/100 gal. Mill's infection periods occurred
consistently through primary apple scab season,
Table 1. Scab control from 'organic' fungicides compared to captan
treatment.
and no
Treatment
Scab incidence (%)
Russet
rating
Primary season
Harvest
Terminal Cluster
Fruit
Lime Sulfur
Lime sulfur + copper
Sulfur + copper
Captan
Control
0.3 c* 0.2 c
0.2 c 0.1 c
3.8 b 4.8 b
1.3 be 1.0 c
8.7 a 9.9 a
8.0 c
1.5 c
28.5 b
5.0 c
97.0 a
1.9 b
2.1 a
1.7 b
2.2 a
1.2 c
'Means in each column
at odds of 19:1.
followed by different letters
are significantly different
22
Fruit Notes, Winter, 1991
with at least two light infections occurring every
week.
Foliar apple scab infections were evaluated on
the basis of all leaves on 40 terminals per tree, 40
clusters per tree, 10 terminals per each row-border-
ing tree, and 10 clusters per each row-bordering
tree. Fruit apple scab infections were evaluated on
the basis 40 fruit per tree, and 10 fruit per each row-
bordering tree. Evaluations for fruit and foliar scab
were collected June 11 and September 18. Russet-
ting was evaluated September 13 on a 1 to 5 scale
related to coverage: l=no russetting, 2=1 to 25%, 3=
26 to 50%, 4= 51 to 75%, 5= 76 to 100%. In addition,
since one of the criticisms of heavy sulfur use has
been that it can acidify soil, we took soil samples in
each treatment. Four samples, 1 per quadrant, were
taken under the center tree in each replication and
pooled. Samples were also taken in the middle of the
drive alley adjacent to each sample tree. Acidity was
evaluated using a standard technique, i. e. measur-
ing soil/water solution with a pH meter.
Lime sulfur and captan treatments showed simi-
lar scab control. However, significant damage was
associated with lime sulfur. This was apparent from
the third application. Leaves were visibly stunted
and had heavy residue deposits. In part, damage
and residues may be attributed to the relatively high
rates and frequent applications. Fruit damage due
to russeting was the most serious short-term prob-
lem caused by sulfur and copper. Our hypothesis is
that the interactions of dormant oil applications and
lime sulfur, captan, and perhaps copper, contributed
to russeting damage. The lime sulfur plus copper
treatment and the captan treatment caused the most
russeting. The heavy russeting in the captan treat-
ment can be explained by the close application of
captan and oil on April 26 and 27, respectively. Lime
sulfur alone or sulfur plus copper resulted in signifi-
cantly less russeting than captan or lime sulfur plus
copper. These results suggest that the lime sulfur
plus copper, either alone or interacting with oil, can
cause more russeting than either material alone. We
cannot be sure how much oil contributed to the
russeting, since oil was applied to all treatments.
Lime sulfur alone offers the most promise for
adequate scab control with the least russeting in a
low-input or 'organic' situation. However, the leaf
damage caused by lime sulfur may be significant. It
also is important to remember that the inoculum
levels in this test block were high, and that in a
commercial block, lower inoculum would allow for
less frequent applications of any fungicide.
There has been some thought that the heavy use
of sulfur on apples could have an adverse effect on
soil. While soil acidity is not the only thing that
needs to be considered, it was interesting that there
were no significant differences in soil acidity among
treatements, or between soil under trees versus soil
in the drive alleys.
Prom: Thotnai, J.J. 1906. The American Fruit
Cultural. Orange Judd Company, New York.
Fruit Notes, Winter, 1991
23
Flyspeck and Sooty Blotch:
New Problems and New Ideas
Daniel R. Cooley, Wesley R. Autio, and James W. Gamble
Departments of Plant Pathology and Plant & Soil Sciences,
University of Massachusetts
For many years, if there was no primary
scab, apple growers would reduce drastically,
and in a few cases eliminate, summer fungi-
cides. Over the past four years, however, the
incidences of the summer diseases have in-
creased. The most dramatic increases have
u .
£ « .
!«
c U
L
•
«■
■
1 1
n
Figu
flysp
1971- 19»7 1981 1989 1990
its*
re 1. Historical levels of sooty blotch and
eck in Massachusetts IPM blocks.
e
«
>
3
O"
UJ
o
o>
a
(0
o
Q
15
10
1982 1984
1986 1988
YEAR
1990 1992
Figure 2. Summer-fungicide use in Massa-
chusetts IPM orchards.
been seen in the diseases flyspeck (Zygophiala
jamaicensis Mason) and sooty blotch (Gloeodes
pomigena (Schw.) Colby), which often occur
together and blemish the surface of apples
(Figure 1). Initial infections of these diseases
start in mid-June, and new infections continue
until harvest. Initially, the IPM programs in
New England felt that these diseases were in-
significant, and in Massachusetts, growers who
successfully controlled primary apple scab ( Ven-
turia inaequalis) were advised that they did not
need to treat any more than 3 times from mid-
June to harvest. Over the period 1978 to 1986,
sooty blotch and flyspeck damage to fruit aver-
aged less than 0.06% in harvest surveys of IPM
blocks. Since then, incidence has climbed dra-
matically, ranging from 0.1% to 0.7%, on aver-
age, and in individual blocks reaching levels in
excess of 10%.
At the same time, fungicide use in the sum-
mer has increased. In Figure 2, summer fungi-
cide use alone (after June 1 5) is shown. Over the
period 1982 to 1987, summer fungicide use was
falling in Massachusetts, as measured in IPM
cooperator orchards, from an average of 5 dos-
age equivalents (DE) to a low of less than 2 DE.
In the last 3 years, summer fungicide use has
risen, as shown in the graph.
We think that the increase in sooty blotch
and flyspeck in recent years may be attributed
to 3 factors:
• Consecutive years of abnormally warm,
wet weather in the Northeast;
• Changes in fungicide use, specifically:
a) a reduction in overall summer
fungicide use;
b) reduction and eventual elimina-
tion of the most effective chemi-
cals (EBDCs) beginning in 1988;
24
Fruit Notes, Winter, 1991
Flyspeck Life Cycle
Ascos pores
are discharged
in rain
Late Pink
Twig and fruit
tissue infected
Fruit Set to
Mid-July
Conidia produced in
lesions spread
during rain and
cause new infections
Mid June to
Harvest
Feritheda form
in orchard and
on wild hosts
Dormant
toPink
Figure 3. The life cycle of Zygophialajamaciencis, the flyspeck pathogen.
c) increasing use of sterol-inhibiting
fungcides, which have no effect on
these fungi, during primary scab
season;
• As a result of the first two factors, increas-
ing inoculum over multiple years.
Of course, with increased pressure, growers
responded by applying more fungicide. The
EBDC fungicides were much more effective
than any other material, and protected fruit for
approximately 45 days. Captan, on the other
hand, protects fruit for about 14 days, and add-
ing Benlate™ or Topsin-M™ increases the
range to about 21 days. It is easy to see, given
the fungicides available and a recent history of
more summer disease damage, that growers
have reason to apply more fungicide.
To develop a way of maximizing the effec-
tiveness of the materials available and perhaps
to reduce the amount used, we examined the life
cycles of the fungi causing the problems. In
Figure 3 the life cycle of the flyspeck fungus is
shown. The general observation is that in warm
wet climates, incidence is higher than in cooler,
drier climates. Optimum conditions for the
disease are said to fall between 65° and 80°F
where humidity exceeds 95%. The fungi which
cause summer diseases generally have a broad
host range. For example, Z. jamaicensis is
known to infect over 100 other species besides
apple. It is fair to assume that the inoculum for
these diseases is always present in virtually all
orchards. However, some alternative hosts may
be more important than others, and Turner
Sutton of North Carolina State University be-
lieves that brambles, particularly blackberry,
are preferred hosts of the fungus.
Previous work has indicated that pruning
may affect flyspeck and sooty blotch incidence in
North Carolina, where disease pressure is much
greater than in New England. Generally, better
pruned trees had less sooty blotch incidence.
However, the results were not consistent from
year to year, and there was no indication
whether decreases occurred because there was
better air circulation, or better fungicide appli-
cation and coverage.
Work on the epidemiology of sooty blotch
and flyspeck has been limited. In 1990, we
undertook a small study to determine whether
summer pruning alone might decrease sooty
blotch and flyspeck incidence. In a block of
mature Mclntosh/M.7 trees, a random selection
of half the trees was summer pruned, while the
remainder was not. No fungicides were applied
over the summer. Disease incidence was rated
Fruit Notes, Winter, 1991
25
Flyt peck-Infected Fruit on Summer
Pruned and NorvPruned Treea
Flyspeck Lesions on Summer Pruned
and Non-Pruned Trees
12
I
£l0
s
- •
I...
i
Not Pruned
Pruned
| 300 .
8 "■ ■
T"
£ 200 .
■
| ISO .
J 100 .
so .
_L
Not
Pruruc
I
Prunsd
Figure 4. The effects of summer pruning on flyspeck intensity and severity.
on September 19. The summer-pruned trees significant value in managing flyspeck and
had only half the flyspeck of controls, and fruit other summer diseases. This is particularly
which were infected had smaller lesions than true in New England, where the summer-dis-
controls (Figure 4). ease pressure is significantly less than it is in
We believe that summer pruning may be of the Southeast and Middle Atlantic region.
From Barry, P. 1872. Barry't Fruit Garden.
Orange Judd and Company, New York.
26
Fruit Notes, Winter, 1991
Summer Pruning, a Continuing Look at
the Benefits
Wesley R. Autio and Duane W. Greene
Department of Plant & Soil Sciences, University of Massachusetts
Since 1986, we have promoted the use of summer
pruning as a partial alternative to the use of Alar™
in Mcintosh apple production in New England. We
have shown that it increases the development of red
color. Additionally, summer pruning results in
earlier development of red color, allowing an earlier
than normal harvest, and thus leaving fewer fruit on
the tree which may drop later in the season. (See the
article on page 20 of this issue for additional benefits
of summer pruning.) In previous Fruit Notes articles
[52(3):7-8; 53(2):1; 53(3):l-2) we discussed some of
the practices and economics of summer pruning. In
this article we shall continue this discussion by
including direct comparisons of the value of summer
pruning with the use of Alar and NAA as drop-
retarding chemicals.
In 1988, seven 6-tree blocks (replications) of 25-
year-old Rogers Mclntosh/M.7 were selected at the
University of Massachusetts Horticultural Re-
search Center in Belchertown. Alar (1000 ppm) was
applied to 2 trees in each block on July 10. NAA (10
ppm) was applied to 2 trees in each block after the
first harvest on September 18. Two trees in each
block did not receive a chemical treatment. In each
block one of the Alar-treated trees, one of the trees
scheduled to receive NAA, and one of the non-treated
trees were summer pruned on August 1. Commer-
cial harvests were performed on September 17 and
27. Twenty fruit were sampled at each harvest for
fruit weight determinations. Additionally, 1 bushel
of fruit was taken from each tree at each harvest,
kept at 32°F for 3.5 months, and graded. The
economic value of these treatments was compared by
constructing a partial budget. Fruit values of $15,
$12, $8, $2.50, and $1.50 per bushel for Extra Fancy,
Fancy, Number 1, Utility, and processing grades, re-
spectively, were used. From the value of the crop,
the costs of both summer and dormant pruning were
subtracted at the rate of $ 7 per hour. Costs of $75 per
acre for Alar and $8 per acre for NAA were sub-
tracted. A value of $10.50 per hectare for the labor
and equipment costs associated with spray applica-
tion was subtracted. Yield-related costs for harvest-
ing of $1 per bushel and for storing and packing of $4
per bushel were also subtracted from the total value.
The resultant number does not reflect profit but
gives a means of comparing the treatments.
As we have reported previously, summer prun-
Table 1. The effects of summer pruning,
with or without NAA or Alar, on packout of Mcintosh
apples and the partial value of the crop
related to these treatments.
Packout (% of total yield)
Partial
Extra
value
Treatment
Fancy
Fancy
No. 1
Utility
Cull
($/acre)
Control
87.6
6.5
0.9
1.5
3.5
3598
b*
NAA
85.7
6.4
0.3
1.1
6.5
4245
ab
Alar
91.2
3.9
0.2
0.9
3.8
4683
a
Summer pruning
95.0
2.0
0.2
1.3
1.6
4838
a
Summer pruning +
NAA
91.4
3.5
0.0
1.4
3.7
4233
ab
Summer pruning +
Alar
92.8
3.5
0.2
1.2
2.3
5026
a
*Means not followed by the
same letter
are significantly different at odds of 19:
1.
Fruit Notes, Winter, 1991
27
ing dramatically reduced the time required to dor-
mant prune, resulting in no increase in total pruning
time (summer plus dormant season). Summer prun-
ing resulted in significantly more fruit picked in the
first harvest (5.9 vs. 4.4 bushels per tree), signifi-
cantly fewer fruit lost to drop (1.7 vs 5.2 bushels per
tree), and a significant reduction in total yield (8.9
vs. 11.6 bushels per tree). This yield reduction can
be attributed to loss during the summer pruning
process, since there was no effect on fruit size.
Table 1 shows the fruit packout from this study.
Chemical treatments had little impact on packout;
however, NAA increased the cull rate. The primary
reason for culling these fruit was excessive bruising,
presumably due to the enhanced ripening and sof-
tening normally associated with NAA treatment.
Summer pruning significantly increased the per-
cent in the U. S. Extra Fancy category and signifi-
cantly reduced the percents in the U. S. Fancy and
cull categories.
The important results of this study are the
differences in partial value associated with these
treatments (Table 1). Summer pruning alone and
Alar alone resulted in similar partial values, each
greater than $1000 more than the control. NAA
alone did not provide significant economic benefits
over the control. For summer-pruned trees, neither
chemical treatment provided significant benefit.
These results accurately detail the benefits of
summer pruning in comparison with the use of NAA
and Alar, giving a clear picture of the packout and
costs. Summer pruning is an excellent alternative to
the use of Alar. It does not perform the same
function, but it compensates for not using Alar by
allowing earlier harvests of more highly colored
fruit.
From: Thomai, J.J. 1906. The American Fruit
Culturitt. Orange Judd Company, New York.
28
Fruit Notes, Winter, 1991
In-Row Rotary Tilling for Orchard
Weed Control
James Schupp and John McCue
Highmoor Farm, University of Maine
Weeds compete with fruit trees for water and
nutrients making weed control necessary to produce
optimum yields of quality fruit. Uncertainty about
the future of herbicide registrations suggests that
alternative methods of weed control should be inves-
tigated. The use of in-row rotary tilling may be a
substitute for the use of herbicides in orchards, so a
study was designed to test the usefulness of this
technique, by itself, and in
combination with other
methods, for weed control
in New England orchards.
growth and fruit size similar to the herbicide treat-
ment. The rotary till alone and in combination with
herbicide resulted in similar yield to the herbicide
treatment; however, the rotary till plus living mulch
treatment yielded less than the herbicide treatment.
Fruit from the herbicide treatment had higher
starch index values (riper), lower soluble solids, and
less red blush, while fruit from the untreated trees
Methods
Three-tree plots of
mature 'McIntoshVM.7
trees were assigned one of
the following weed control
treatments: 1) untreated
control; 2) herbicide spray
(Gramoxone™ plus
Surflan™) applied at tight
cluster; 3) rotary tilling
(Weed Badger™) applied
at tight cluster, mid-June,
and late July; 4) rotary
tilling plus Surflan; and 5)
rotary tilling plus a living
mulch (oats), sown in Au-
gust.
Results
The untreated control
resulted in less tree
growth than all other
treatments and lower yield
than the herbicide treat-
ment (Table 1). The un-
treated controls also had
significantly fewer large
fruit than the herbicide
treatment. The rotary till
combinations resulted in
Table 1. Growth and yield of Mclntosh/M.7 apple trees with five
different weed control methods in 1989.
Treatment
Untreated
Herbicide
Rotary till
Till + herbicide
Till + live mulch
Total
Yield of
Trunk growth
yield
96+-count fruit
(cm 2 )
(lbsAree)
(lbsAree)
57 b*
39 b
3 b
78 a
76 a
11 a
77 a
69 ab
9 ab
83 a
70 ab
9 ab
77 a
57 b
4 ab
*Means within columns not followed by the same letter are signifi-
cantly different at odds of 19:1.
Table 2. Effects of five different weed control methods on weed control
in the orchard row.
Treatment
Weed control rating
*
July, 1989
August, 1989
May, 1990
Control
Herbicide
Rotary till
Till + herbicide
Till + live mulch
1.1 c**
3.9 a
3.3 b
4.1 a
1.1 c
4.0 a
2.9 b
3.3 b
1.1 c
3.9 a
2.4 b
3.7 a
3.7 a
*Weed rating: 1 = many weeds to 5 = no weeds.
**Means within columns not followed by the same letter
cantly different at odds of 19:1.
are signifi-
Fruit Notes, Winter, 1991
29
had a lower starch index values (less ripe), higher
soluble solids, and higher flesh firmness (data not
shown). Fruit quality measurements from all 3
rotary till treatments were intermediate. Rotary
tilling provided less weed control than the herbicide
treatment, although weed control with tilling was
considered commercially acceptable (Table 2).
Combining rotary tilling with a living mulch or with
a pre-emergent herbicide provided better weed con-
trol than rotary tilling alone or the control.
Discussion
The most striking comparison in the first year of
this study is the untreated control vs. any of the weed
control treatments. Clearly, the competition created
by the weeds is as detrimental to the productivity of
bearing trees as it is to the growth and development
of young trees. Weed control is a cumulative process,
and it will be interesting to see how the rotary tilling
treatment performs in subsequent seasons.
As with all new technology, a few problems
remain to be solved. The in-row rotary tiller is a
complicated piece of equipment that requires com-
plete operator attention and slow operating speed. It
removes shallow roots, and low hanging branches
become entangled in the equipment. Tilling tends to
build a berm at the edge of tilled area. Also, the tiller
kicks rocks into the drive row causing problems for
mowers. The rotary tiller is not designed to be a
"sodbuster," so weed control must be reasonably
good at the outset in order to achieve good results.
Our preliminary results suggest that the in-row
rotary tiller may be useful as a substitute for chemi-
cal weed control. Further studies are underway at
Highmoor Farm to learn how this technology can be
made more practical for New England apple grow-
ers.
Acknowledgements
The authors wish to thank the Technology
Transfer Program, Maine Department of Agricul-
ture, Food & Rural Resources, and the Maine State
Pomological Society for support of this research.
From Barry, P. 1872. Barry'* Fruit Garden.
Orange Judd and Company. New York.
30
Fruit Notes, Winter, 1991
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Fruit Notes, Winter, 1991 31
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Fruit Notes
•epared by the Department of Plant & Soil Sciences.
niversity of Massachusetts Cooperative Extension,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
ISSN 0427-6906
SCi Li
PR
Volume 56, Number 2
SPRING ISSUE, 1991
Table of Contents
Development and Implementation of
Northeast Strawberry IPM
Acey Mac and Pioneer Mac, Are They Going
to Save the Mcintosh Industry In New England?
An Update on Dwarfing Root stocks In the 1984
NC- 140 Apple Rootstock Planting tn Massachusetts
A Re-examination of the Boron Recommendations
for Apple Trees In Massachusetts
Second-level Apple IPM
Scare-eye™ Balloons for Controlling Flocking Birds in Orchards
Efficient Use of Sterol-inhibiting Fungicides:
Questions and Answers About the Delayed 10-day Program
^\
Fruit Notes
Publication Information:
Fruit Notes (ISSN 0427-6906) is published the first day of January, April,
July, and October by the Department of Plant & Soil Sciences, University
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v=
Development and Implementation of
Northeast Strawberry IPM
Daniel R. Cooley, Sonia G. Schloemann, Mark Mazzola,
and Barbara Schloemann
Deptartment of Plant Pathology, University of Massachusetts
The Strawberry IPM program in Massachusetts
began in 1987. The first step in the program was to
establish what the key pests were in Massachusetts,
and what growers were doing to manage them.
Through a survey, we found that growers considered
Botrytis gray mold their most important problem,
followed by tarnished plant bug (Lygus lineolaris),
strawberry bud weevil {Anthonomus signatus), two
spotted mite (Tetranychus urticae), and black root
rot (a disease complex caused by the lesion nematode
Pratylenchus and the fungus Rhizoctonia). Weeds
were also considered of major importance. Of course,
there are other pests which can be important, and
the situation changes from year to year. For ex-
ample, leaf spot, angular leaf spot, leaf scorch, and a
Phomopsis blight have all appeared as significant
problems in some fields over the past 2 seasons.
However, other than making sure that the growers
use effective techniques at the appropriate times,
there is no true IPM system for these problems.
We were unsure of the pest management strate-
gies used by growers. The strawberry pest manage-
ment recommendations of 1987 suggested that
growers make 8 to 14 fungicide applications, 4 to 8
insecticide-miticide applications, 1 to 3 herbicide
applications, and fumigate before planting. A 1987
survey showed that Massachusetts strawberry
growers averaged 2.0 insecticide applications (range
of - 7), 5.6 fungicide applications (range of - 15),
and 2.7 herbicide applications (range of - 5).
Given the pesticide use information and evalu-
ations of pest priorities, we began work in those
areas where we could deliver information quickly
with the most benefit. Conveniently, we had meth-
ods available for management of Botrytis , tarnished
plant bug, and mites and thus began the significant
portions of the program.
Botrytis IPM
Strawberry growers fealt that their most impor-
tant pest problem was gray mold. Since it is a
disease, some of the techniques typically used in IPM
are not available.
Organisms which cause disease, such as fungi
and bacteria, cannot easily be observed in the field.
Symptoms can be seen, but spores and hyphae gen-
erally cannot be seen with the unaided eye. So, it is
not easy to find the spores and bacteria which start
a disease epidemic. Growers are faced with the prob-
lem of either treating before symptoms appear on the
assumption that the spores and bacteria are there or
treating after symptoms appear at a time when it
may not be possible to stop the epidemic. In the
former case, the disease organism may not be pres-
ent, thus the grower may over-treat. In the latter
case treatment may have little impact on the prog-
ress of the disease, since with many diseases, by the
time symptoms are there, the disease has gone
beyond the action threshold. While some disease
may be tolerable, a lot of disease is not. Therefore,
action thresholds based on symptoms are generally
very low. Fortunately there are other things, be-
sides spores and infection symptoms, that can be
used to monitor the progress of a pathogen. In order
to do this, we must understand the disease more
thoroughly.
Botrytis has a more complex life cycle than
scientists have generally assumed. In the past few
years, work by Dr. John Sutton and Dr. Gordon
Braun in Canada (Braun and Sutton, 1987; Sutton
and Braun, 1987) and Dr. Michael Ellis in Ohio, has
shown how Botrytis functions and suggests how to
best control it. Like many fungi, Bortryt is cinerea is
active under moist conditions. Rain, dew, or sprin-
klers can provide an environment for the disease to
become active.
Symptoms on the fruit are largely as the com-
mon name suggests-a gray mold. Fruit may rot rap-
idly just before or just after the fuzzy gray fungus
growth appears. Much of the time, however, in-
fected parts of the plant appear normal. The fungus
remains dormant, but alive. Only when the plant
tissue nears the end of its natural life do symptoms
Fruit Notes, Spring, 1991
such as rotting and leaf-spotting appear. The gray,
fuzzy areas actually are masses of spores. These
spores infect young tissue, and the new infections
remain dormant until the tissue is fully mature.
Most of the important fruit infections occur at
bloom. Spores from decaying leaves infect flower
petals. If conditions are wet, these infections may
kill the flowers or the new developing fruit. Under
normal conditions, the infections remain dormant in
the fruit, and when the fruit become ripe, infections
grow rapidly. Infections can spread rapidly from
infected fruit to nearby uninfected fruit. Again, the
more moisture, the faster the spread. After the
strawberry is done fruiting, the fungus infects new
leaves on the plant throughout the summer. The
fungus then overwinters in infected but apparently
healthy leaves. These leaves produce spores the
following spring, and the cycle repeats.
Management. How does this information sug-
gest that we should manage the disease? We real-
ized immediately that growers were concentrating
at least half of their fungicide applications on the
ripening berries. This situation was bad from two
points of view. First, most of the infections had
already occurred and were in the berries. Second,
the fungicide residue was being left on the fruit
which consumers were going to harvest and eat.
Our management technique sought to break the
Botrytis life cycle. As a first step, we aimed to protect
blossoms from infection, rather than the berries.
Our recommendation was to apply a fungicide up to
3 times during bloom. In many years, a single early-
bloom application will protect fruit. If more than 1
application is used, we recommended that they be
spread about 7 days apart. Later we modified this
recommendation, suggesting making the first appli-
cation at 10% bloom, the second at mid-bloom, and
the final application when bloom was about 90%
done.
The cycle can also be broken in fall or early
spring. Benlate™ or Topsin-M™ plus captan or
thiram applied once late in the growing season
(September or October) will also reduce overwinter-
ing inoculum. However, Benlate and Topsin-M may
be toxic to some mite predators in strawberries, and
may hurt attempts atmite biocontrol. Alternatively,
Ronilan™, while more expensive, may be combined
with captan or thiram and used to reduce the over-
wintering inoculum. The same treatment may be
useful in spring. In some cases, this single applica-
tion in combination with "clean" cultural practices
will be sufficient to remedy a building gray mold
problem, and eliminate the need for more sprays.
Cultural practices can play an important role in
managing gray mold. Narrow plant rows and wide
spacing between rows will allow greater air circula-
tion, better drying, and better pesticide coverage.
Rapid drying of foliage, blossoms, and fruit during
periods of high humidity, rain, irrigation, or dew will
decrease the chance of Botrytis spores germinating
on plant surfaces. Beds that become too crowded are
likely to promote Botrytis fruit rot. So, "clean"
cultural practices mean keeping weeds down and
keeping plant rows aerated. In the future, it may
mean literally cleaning out the old, dead leaves in
the planting.
What we have done in developing IPM for Bot-
rytis is substitute phenological monitoring for pa-
thogen monitoring. We know that the plant and
pathogen evolved together. The pathogen is ready to
infect the host plant when conditions are optimum
for the pathogen's survival. Both the plant and
pathogen develop in response to the same stimuli,
which generally are temperature and moisture. By
watching plant development, fungicides which pro-
tect the plant and destroy the pathogen can be timed
well. It is not quite as accurate as watching the
pathogen directly, but it is infinitely easier.
Since temperature and moisture both pro-
foundly affect the pathogen, we might also monitor
these variables. Mike Ellis has developed a model
and it may allow us to refine this recommendation,
and apply fungicides in response to measured infec-
tion periods.
Mite IPM
Two-spotted mite (TSM) feeding in small fruit
crops results in yield loss and a reduction in plant
vigor (Oatman et al., 1981). Few miticides are
labeled for strawberries, making an alternative
method of mite control critical. Further, resistance
to miticides is common and jeopardizes their future
utility (Gould, 1973). We knew of the effectiveness
of the predatory mite Amblyseius fallacis in control-
ling TSM populations in various crops including
strawberries (Croft and Hoyt, 1983).
Soon after the Massachusetts IPM program
started, we were faced with a severe problem in
dealing with mites. Chemical miticides were either
ineffective or were withdrawn from the market.
Growers had no alternative but to try biological
control. We assisted growers with the introduction
of mite predators, Amblyseius fallacis (Biokon In-
sectaries, 34 Bay Rd., Belchertown, MA 01007, other
companies also rear mite predators). Additionally,
we recommended that growers refrain from using
Benlate, Topsin-M, or Lorsban™, since these mate-
Fruit Notes, Spring, 1991
Table 1.
Relative toxicity
of commonly used
strawberry pesticides to mite
predators.
+ = low
toxicity; +++ = high toxicity.
This information is
based on 1
ab tests of limited populations.
Material
Toxicity
Guthion
+
Lorsban
++
Parathion
+
Pydrin
+++
Sevin
++
Kelthane
++
Morestan
+
Vendex
+
Benlate
++
Captan
+
Ronilan
+
Thiram
+
rials may be toxic to the predators and interfere with
biocontrol (see Table 1). Under favorable conditions,
A fallacis reduced TSM populations from outbreak
levels (> 5 per leaf and reaching 19 per leaf) to below
1 mite per leaf within a 2 week period during the first
2 years of study. Results from 1988 and 1989 sug-
gested that the presence of the predatory mites were
as beneficial as miticide applications, and that in-
digenous populations of predators were almost as
effective as released populations. These results were
gathered from 16 cooperating growers each year.
Scouting mites. TSM are very small (1/50"),
insect-like creatures that feed on strawberry foliage.
Under heavy infestations, TSM feeding destroys
leaf chlorophyll and causes leaves to appear bronze
Sampling Path
for Mites, Plant Bug
Nymphs, and Clipper
Sample at 5 to 10
locations per field
Tamijhed
Plant Bug
Tiap*
7
Figure 1 . Insect and mite sampling pattern in a straw-
berry field.
in color. Yield reductions may occur from repeated
heavy infestations. TSM are found on the underside
of leaves, are barely visible to the naked eye, and are
especially active during hot, dry months. TSM
generally form colonies and may be most noticeable
by the webbing that they produce in the vicinity of
the colonies. These colonies are usually localized in
"hot-spots" in the field rather than being evenly dis-
tributed throughout the field. Therefore, when
looking for mites, the grower must look over the
whole field, checking first for bronzing and then
looking for mites with a hand lens. TSM and insects
are sampled using the V-pattern walk in the field,
with 5 to 10 sample locations (see Figure 1). Approxi-
mately 5 leaves should be sampled at each locations.
(Normally, we place a 2-square foot marker at each
sample location and sample inside it for TSM and
other pest problems.) Predators should be noted as
well. Unfortunately, there is no strict threshold. We
recommend predator release (cost is $10.00 per acre)
when populations are building from week to week,
and the number of mites per leaf reaches 5 in a 50 leaf
sample. It is still not clear whether this action
threshold is appropriate.
Tarnished Plant Bug IPM
Tarnished plant bug (TPB), Lygus lineolaris, is
a major pest of strawberry, whose feeding on flowers
and immature fruit results in misshapen, seedy, and
unmarketable fruit. Losses due to TPB damage can
reach levels of 60 to 70% of the crop (Schaefers,
1980). Initially, we had hoped to be able to monitor
plant bug using a sticky visual trap (white square).
Unfortunately, we could not establish an action
threshold, though we caught many adult tarnished
plant bugs. However, a threshold has been estab-
lished for TPB nymphs and nymphs seem to be
causing at least as much damage as the adults.
Between the two techniques, treatments for TPB can
be made more precise.
Scouting for TPB. TPB is a small (1/4") bronze-
colored insect with a triangular marking on its back.
The immature stage, or nymph, is smaller and bright
green, resembling an aphid, but much more active.
Both adults and nymphs feed on the developing
flowers and fruit, sucking out plant juices with
straw-like mouth parts. This feeding results in
deformed fruit; typically "cat-faced" berries, also
called "nubbins" or button berries. Such fruit are
generally unmarketable.
To determine when adult TPB are active and
moving into the field, place white sticky traps
around the edge of the field (see Figure 1). Nymphs
Fruit Notes, Spring, 1991
are sampled in a V-pattern as with TSM by shaking
2 to 4 flower clusters over white cardboard at each
sampling location (at least 20 flower clusters
should be sampled across the field). If average
nymph counts exceed 1 nymph per cluster, then a
petal-fall insecticide application should be made. Do
not apply insecticides during bloom. If TPB
have been a serious problem in the past, an early-
season insecticide application may be made prior to
10% bloom to target the egg laying adult females.
This treatment should be made on a sunny, warm
day when the insects are active.
Controlling weeds in and around the planting
may reduce populations of this insect, but insecticide
sprays generally are necessary. Combining such
sprays with treatment for clipper, where necessary,
can save an insecticide.
We have also started to study a potential preda-
tor of TPB. Peristenus digoneutis, a braconid wasp
parasite of the alfalfa plant bug, Lygus hirsuta, and
TPB, was introduced into the United States by
USDA entomologist Dr. William H. Day. While the
parasite was introduced for control of plant bug in
alfalfa, Dr. Day feels that it has potential for control
of TPB in strawberries. The parasite has been estab-
lished in northern New Jersey with parasitism rates
of TPB nymphs in an alfalfa field ranging from 50 to
90%. In 1990, two collection trips were made to New
Jersey. Parasitized TPB nymphs were released at
two sites in Massachusetts. Plans for 1991 include
more collection trips and monitoring for the estab-
lishment of the parasite at the previous year's re-
lease sites. Dr. Day estimates an establishment
period of 3 to 5 years. Once the parasite is estab-
lished, further work will need to be done to deter-
mine efficacy of the parasite
in controlling TPB in straw-
berries.
with a copper-colored body and a black head with a
long snout.
The female weevil chews a small hole in un-
opened flower buds and lays an egg in the hole. She
then girdles the stem just below the bud. The flower
bud dries up and dangles from the stem, eventually
falling to the ground. The immature weevils, or
grubs, develop in the girdled buds, emerging as
adults in the early summer, and then migrating to
wooded areas.
Scouting for clipper. These insects are not al-
ways present and may only cause minimal damage
some years. Examine the plants before bloom for
clipped buds. As with TSM sampling, a V-shaped
transect should be made in the field with 5 to 10 sam-
pling locations. A 2-foot section of row should be
examined at each location. A samplingframe may be
made for this purpose. If an average of 0.6 clipped
buds per foot of row is reached, control measures
must be taken. As mentioned above, Lorsban should
be avoided if TSM are a problem.
Impact of the Strawberry IPM Program
Ten cooperating growers were enrolled in the
program in 1990, as compared to 16 growers in 1989.
This decrease was due to a decreased operating
budget from 1989 levels, requiring us to drop some of
the smaller growers or those isolated from other
growers. However, 48 acres were scouted by the
program in 1990 (only three acres less than in 1989)
with an additional 51 acres scouted privately under
our supervision. Together this total represents ap-
proximately 20% of the commercial acreage in the
Massachusetts.
Under IPM recommendations, cooperating
Strawberry Bud Wee-
vil ("Clipper") IPM
This insect can build up
quickly, so the action
threshold is relatively low.
The sampling procedure can
miss rapid build-up of the
pest if done on a weekly
basis. This insect occurs
somewhat less frequently
than tarnished plant bug
but causes economic injury
where it does occur. The
insect is a very small beetle
Table 2. Average dosage equivalents of pestide used on
non-IPM and IPM
commercial strawberry farms
in Massachusetts from 1987
through 1990.
Dosage equivalents of pesticide used
Non-IPM
IPM
Pesticide
group
1987
1990
1988
1989
1990
Miticides
0.4
0.2
0.1
0.1
0.2
Fungicides
4.1
3.5
2.1
2.5
2.9
Insecticides
1.6
1.9
1.0
1.1
1.5
Fumigants
0.5
0.4
0.3
0.3
0.3
Herbicides
2.5
2.5
2.0
1.5
1.2
Total
9.1
8.6
5.5
5.4
6.0
Fruit Notes, Spring, 1991
growers reduced pesticide application (dosage
equivalents) by approximately 40% in both 1988 and
1989 as compared to 1987 baseline practices. In
1990, non-IPM spray practices were re-examined by
locating non-IPM growers and pairing them with co-
operating growers by location. Spray records were
obtained for comparison and harvest surveys were
conducted to compare yield and quality of IPM and
non-IPM growers for 1990. Harvest surveys were
conducted at non-IPM sites within 24 hours of sur-
veys at cooperating growers to standardize field con-
ditions. Beds of comparable age and cultivars were
selected for comparison.
Results show that pesticide applications (in
dosage equivalents) were approximately 31% lower
among cooperating growers than for fields under
conventional (non-IPM) management in 1990 (Table
2). Harvest surveys indicate no significant differ-
ence in yield or quality between IPM and non-IPM
growers surveyed.
Conclusion
We realize that we are not covering all the
problems faced by strawberry growers. However,
the IPM program has provided the impetus and
some funds to start research in other areas. We are
particularly concerned with finding alternatives to
soil fumigation, management techniques for black
root rot, alternatives to fungicides used on Botrytis,
and a program for weed management. We would like
to acknowledge the support given us by the Massa-
chusetts IPM program, the Low-Input Sustainable
Agriculture program of the USDA, the Massachu-
setts Biological Control program, the North Ameri-
can Strawberry Growers, and especially Nourse
Farms, Inc., without whom this work would have
been impossible.
References
Braun, P. G. and J. C. Sutton. 1987. Inoculum
sources of Botrytis cinerea in fruit rot of strawberries
in Ontario. Can. J. Plant Path. 91:1-5.
Croft, B. A and S. C. Hoyt, eds. 1983. Integrated
Management of Insect Pests of Pome and Stone
Fruits. John Wiley & Sons, NY.
Gould, H. J. 1973. Laboratory and field investiga-
tions with organophophorus resistant Tetranychus
urticae on strawberries. Ann. Appl. Biol. 74:17-23.
Oatman, E. R., J. A. Wyman, H. W. Browning, and
V. Voth. 1981. Effects of releases and varying
infestation levels of the two-spotted spider mite on
strawberry yield in southern California. J. Econ.
Entomol. 74:112-115.
Schaefers, G. A. 1980. Yield effects of tarnished
plant bug on June-bearing strawberry varieties in
New York State. J. Econ. Entomol. 73:721-725.
Sutton, J. C. and P. G. Braun. 1987. New methods
for controlling grey mold fruit rot (Botrytis cinerea)
in strawberries. Proc. Ontario Hort. Crop Conf.
Fruit Notes, Spring, 1991
Acey Mac and Pioneer Mac,
Are They Going to Save the
Mcintosh Industry in New England?
Wesley R. Autio and Duane W. Greene
Department of Plant & Soil Sciences, University of Massachusetts
In New England we grow a large number of
Mcintosh apples, primarily because the environ-
mental conditions allow us to produce a better Mcin-
tosh than anywhere else in the country. However,
the "Alar Crisis" has forced many growers to look se-
riously at reducing their Mcintosh acreage.
To assess the degree of change which was being
contemplated in New England, we conducted a sur-
vey of the apple industry. In 1989, Mcintosh ac-
counted for 59% of the planted apple acreage, and is
expected to decline to about 53% by 1994. This
reduction in Mcintosh acreage is confirmed by plant-
ing trends. Over the last 10 years, Mcintosh has
accounted for 50% of the planting. This will be
reduced to 38% over the next 5 years; however, it is
important to note that the next most prominent
cultivar will account for only 13% of the planting.
Although the Mcintosh picture is changing, it will
remain the dominant cultivar for a number of years
to come.
Where a heavy concentration of Mcintosh is
maintained, growers must consider means of alter-
ing their management practices to cope with the loss
of Alar. Summer pruning, detailed fertility manage-
ment, the use of NAA and ethrel, and increased labor
can all assist in expanding or altering the harvest
season so as to reduce losses from preharvest drop.
Likewise, detailed fertility management, accurate
maturity assessment, and careful fruit handling will
help maintain fruit quality. These changes, how-
ever, are short-term alternatives which will reduce
only some of the losses associated with not using
Alar. Growers must undertake appropriate long-
term solutions to overcome the need for Alar. Re-
placing Mcintosh with other cultivars is one way of
eliminating the need for Alar. Using dwarfing
rootstocks to decrease tree size, enhance fruit color-
ing, expand the ripening season, and increase the
rate of harvest can reduce the need for Alar. The
harvest season can be expanded by planting strains
of Mcintosh that differ in time of ripening. As new
Mcintosh acreage is planted or present acreage is
rejuvenated, growers must plan carefully and estab-
lish a strain mix which will give some advancement
as well as delay in the harvest season.
Early-season strains of Mcintosh include
Marshall Mcintosh and Redmax. Marshall ripens
approximately 1 week earlier than standard strains
and colors about 10 days earlier. Marshall allows
both an earlier beginning to the harvest season and
a harvest of a larger portion of the crop in the early
part of the season. Redmax ripens similarly to
standard strains, but Redmax fruit color at least 2
weeks earlier. Therefore, Redmax does not allow an
earlier beginning to the season but will allow a larger
portion of the crop to be harvested in the early part
of the season. Those growers considering the use of
Redmax must be aware that its red color is a stripe,
so only locations with good coloring conditions
(Maine, New Hampshire, Vermont, and northern
Massachusetts) should plant it.
Two new Mclntosh-like cultivars have been re-
leased recently which potentially will allow a late-
season expansion of the harvest season. These are
Acey Mac and Pioneer Mac. Reports have suggested
that these are similar enough to Mcintosh to be sold
as Mcintosh, that they ripen 5 to 14 days after
Mcintosh, and that they do not drop as severely as
Mcintosh. The remainder of this article will discuss
the history of these two cultivars and early results
with them at the University of Massachusetts.
Acey Mac
Acey Mac originated from a seedling tree discov-
ered by Art Burrill in the Champlain Valley of New
York and is available from Columbia Basin Nursery
(Quincy , WA). Reports have suggested that fruit are
very similar to Mcintosh, ripen about 5 days later,
and drop to a lesser degree than standard Mcintosh.
Acey Mac trees were planted at the Horticul-
tural Research Center in Belchertown, MA in 1989.
Fruit Notes, Spring, 1991
We obtained our first fruit in 1990. Obviously, we
cannot make a lot of conclusions from this early
fruiting; however, Acey Mac clearly is not a
Mcintosh. Its appearance is similar to Spartan,
and it ripens approximately at the same time as
Spartan. Flavor seems distinguishable from both
Mcintosh and Spartan. Acey Mac could provide a
desirable expansion of the harvest; however, it is
not similar enough to Mcintosh to be used in this
scheme.
Pioneer Mac
Pioneer Mac was discovered as an open polli-
nated seedling of Mcintosh at Ernest Greiner's farm
in Marlboro, NY. Trees of Pioneer Mac are available
from Adams County Nurseries (Aspers, PA). Early
reports suggested that fruit are very similar to
Mcintosh and that they ripen about 10 days later.
Pioneer Mac trees were planted at the Horticul-
tural Research Center in 1988. We harvested our
first fruit in 1990. Although relatively small num-
bers of fruit were available, it was clear that this
cultivar could be sold as a Mcintosh. Fruit appear-
ance and quality were virtually indistinguish-
able from Mcintosh. These trees were too young
in 1990 to provide an accurate assessment of fruit
ripening; however, fruit appeared to ripen at a
similar time to Rogers Red Mcintosh and signifi-
cantly later than Marshall Mcintosh. These data
confirm the current information from Adams
County Nurseries, suggesting that Pioneer Mac
ripens in the standard Mcintosh ripening period and
not 10 days later. The potential advantage of Pio-
neer Mac, however, is its reduced level of preharvest
drop. Dr. Chick Forshey has shown that Pioneer
Mac displays significantly lower levels of drop than
Rogers. It will be a number of years before we can
confirm this result adequately.
In conclusion, orchardists must consider many
short- and long-term management changes to grow
Mcintosh successfully without Alar. A blend of
Mcintosh strains which provide a clear expansion of
the harvest season is one way to reduce the need for
Alar. Early-season expansion is provided by
Marshall Mcintosh and Redmax. For late-season
expansion, Acey Mac will not be useful, because it is
not a Mcintosh substitute. Pioneer Mac, however,
still shows potential if additional studies confirm
results showing that it does not drop as readily as
Mcintosh.
Fruit Notes, Spring, 1991
An Update on Dwarfing Rootstocks
in the 1984 NC-140 Apple Rootstock
Planting in Massachusetts
Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
Throughout New England there is a great deal of
interest in dwarfing rootstocks. The New England
Apple Survey, conducted in 1989, showed that only
14 % of the acreage planted between 1985 and 1989
was planted to trees on dwarfing rootstocks. Grow-
ers predicted, however, that from 1990 to 1994, 62 %
of the acreage planted would be planted to dwarfing
rootstocks. Many new rootstocks in the dwarfing
category are becoming commercially available, and
a number of these have been under study in Massa-
chusetts. Because of the host of potential problems
with new rootstocks, growers should be cautious
when new selecting rootstocks. In this article I will
give a brief update on some of these new rootstocks.
In 1984, a cooperative planting of the NC-140
Rootstock Research Committee was established at
the University of Massachusetts Horticultural Re-
search Center in Belchertown, MA. The scion culti-
var was Starkspur Supreme Delicious, and the root-
stocks under study include Bud. 9, Bud.490, MAC 1,
MAC 39, P.l, P.2, P.16, P. 18, P.22, C.6, M.4, M.7
EMLA, M.26 EMLA, Ant.313, and seedling. The
degree of dwarfing ranges from ultradwarf to stan-
dard. In this article I will report results only from
those in the dwarf and ultradwarf categories.
Table 1 reports the trunk cross-sectional area,
yield, and yield efficiency of trees on P. 16, P.22, P.2,
Bud.9, MAC 39, C.6, and M.26 EMLA. Trees on P.16
and P.22 were ultradwarf, producing trees roughly
similar in size to M.27. P.2 produced a tree similar
in size to M.9, and Bud.9 and MAC 39 were between
M.9 and M.26 in size. C.6 produced a tree similar in
size to M.26. All 7 of these combinations need trunk
support.
The highest yielding trees in 1990 and on a
cumulative basis were on C.6. However, because of
the size difference among trees on these 7 rootstocks,
it is necessary to compare yield efficiencies, which
relate yield to tree size and give a rough way to
compare potential yields per acre. In 1990, trees on
Bud.9, MAC 39, P.2, P.16, and C.6 were more effi-
cient than those on P.22. On a cumulative basis,
trees on Bud.9, P.2, P.16, and C.6 were more efficient
than those on MAC 39 and M.26 EMLA.
Table 1. Trunk
cross-sectional area,
yield, and yield efficiency in
1990 and on a
cumulative basis of Starkspur Supreme Delicious on various dwarfing rootstocks
planted in 1984
Yield efficiency
Yield per tree (bu)
(lbs/in 2 TCSA)
TLSA
Rootstock
(in 2 )
1990
Cumulative
1990
Cumulative
P.16
0.9
0.5 c
1.1 c
24.5 ab
51.9 a
P.22
1.0
0.5 c
1.1 c
19.9 c
45.2 ab
P.2
2.1
1.3 b
2.6 b
26.9 a
53.6 a
Bud.9
2.7
1.6 ab
3.1 b
25.0 ab
50.1 a
MAC 39
3.2
1.7 ab
3.1 b
22.3 abc
39.2 b
C.6
3.8
2.1 a
4.4 a
24.6 ab
52.6 a
M.26 EMLA
3.9
1.8 ab
3.3 ab
20.8 be
38.4 b
Fruit Notes, Spring, 1991
C.6
Bud.9
M.26 EMLA
P.2
P.22
10/1
10/8 10/15 10/22
Date of log ethylene
10/29
Figure 1. The effect of various dwarfing and ultradwarfing rootstocks on the ripening of Starkspur
Supreme Delicious fruit in 1990. The date of log ethylene approximates the date of the beginning
of ripening.
Clearly, trees on P.2, C.6, and Bud.9 have per-
formed very well so far. Additionally, trees on P. 16
and P.22 have been very yield efficient; however,
growth has been poor and trees have become spur-
bound. Trees on P.16 and P.22 will not remain yield
efficient because of these problems. The protocol of
the experiment has not allowed us to thin fruit from
these very small trees which are overfruiting, nor
has it allowed staking of the trees until they fall over.
The lack of staking severely limits the growth and
development of these trees.
Ripening of fruit from these trees was assessed
in 1990 (Figure 1). One year of data is not adequate
to make clear conclusions regarding ripening; how-
ever, dramatic differences existed in 1990. Fruit
from trees on P.2 ripened 1 week later than those
from trees on C.6, and fruit from trees on P.22
ripened approximately 9 days later than those from
trees on P.2. If this effect is consistent, we may be
able to utilize these rootstocks to expand the harvest
season dramatically; however, several additional
years of data are required to assess this effect accu-
rately.
Study of the rootstocks in this planting will
continue for several years to assess performance as
well as potential barriers to their use commercially.
A new planting is scheduled to be established in 1993
which will include several new dwarfing rootstocks,
some of which have not been released prior to their
use in this planting.
Fruit Notes, Spring, 1991
A Re-examination of the Boron
Recommendations for Apple Trees
in Massachusetts
William J. Bramlage and Sarah A. Weis
Department of Plant & Soil Sciences, University of Massachusetts
Boron (B) is an essential element for plant
growth, and in Northeastern North America apple
growers must contend routinely with its deficiency.
B deficiency can reduce tree growth, cause corking
in fruit, and cause premature fruit drop. B defi-
ciency also interferes with movement of calcium (Ca)
in plants, and can therefore cause or antagonize a Ca
deficiency problem in apples.
Our primary recommendation for B treatments
in apple orchards has been to apply B to the soil every
third year [Fruit Notes 49(2):8-13]. The actual
Table 1. Treatments used in the experiment to re-examine B
recommendations for apple trees.
Treatment
Average lbs of actual B that
would be applied per acre per
year during a 6-year cycle
1. 1 lb borate/tree*,
1989 only
5
2. 1 1/3 lbs borate/tree,
1988 only
10
3. 1 lb borate/tree,
1987, 1988, and 1989
15
4. 1 1/3 lbs borate/tree,
1987, 1988, and 1989
20
5. 1 2/3 lbs borate/tree,
1987, 1988, and 1989
25
6. 1/2 lb Solubor/100
gallons dilute at first
2 cover sprays*
5
7. 1 lb Solubor/100 gallons
dilute at first 2 cover
sprays
10
"Treatments recommended to commercial apple growers in
Massachusetts.
amount of B to be applied varies with tree size. An
alternative approach is annual foliar applications of
Solubor™ in the first two cover sprays.
In New York, recommendations for B applica-
tions in apple orchards are different from ours [Fruit
Notes 47(2):20-26]. There, annual treatments,
whether through soil or foliar application, are rec-
ommended, and higher application rates are sug-
gested for certain conditions.
To re-examine the adequacy of our B recommen-
dations, we carried out a 4-year experiment at the
Horticultural Research Center in
Belchertown. In 1987, the experi-
ment was established in a block of
Marshall Mcintosh trees on M.7A
rootstock, planted in 1981.
A complex set of treatments was
designed to test our current recom-
mendations against various modifica-
tions of these recommendations
(Table 1). Thus, one treatment con-
sisted of 1 lb of borate per tree applied
to the soil every third year. (Since all
trees in this block received this treat-
ment in 1986, it would be applied in
1989.) A second treatment consisted
of annual sprays of 1/2 lb of Solubor
per 100 gallons of water at the first
and second cover sprays. (These two
treatments are the options that we
recommend.)
The modified treatments were: 1
1/3 lbs of borate per tree every second
year, 1 lb of borate per tree every year,
1 1/3 lbs of borate every year, and 1 2/
3 lbs of borate every year. Also, one
treatment consisted of Solubor
sprayed at 1 lb per 100 gallons of
water at the first two cover sprays
(twice our recommended rate).
We hoped to evaluate our recom-
mendations by comparing the bene-
10
Fruit Notes, Spring, 1991
Table 2. Effects of boron treatments on leaf B concentrations
in Mclntosb apple
trees.
Leaf B (ppm)
Treatment
(see Table 1)
1987
1988
1989
1990*
1
43
42
75
50
2
43
95
61
47
3
81
96
89
53
4
84
103
90
52
5
80
113
85
55
6
52
51
53
43
7
61
62
66
47
'No treatments were applied
in 1990,
to measure
carryover
effects.
fits from soil and foliar treatments, from soil treat-
ments applied every 3, 2, or 1 year, and from differ-
ent rates of both soil and foliar applications. The
experiment was replicated 7 times, and both leaves
and fruit were sampled for analysis. Fruit quality
also was assessed in some years. Treatments were
applied in 1987, 1988, and 1989. In 1990, no tree
received any B, to assess the carry-over effects of the
treatments in previous years on leaf B concentra-
tions.
Leaf analyses recorded during this experiment
are presented in Table 2. All soil applications of
borate sharply increased leaf B in the year of appli-
cation. It made little difference whether application
was at a rate of 1, 1 1/3, or 1 2/3 lbs per tree. Foliar
applications were considerably less effective than
were soil applications, even at twice the recom-
mended rate. (This probably was
due to the small amount of leaf
surface for absorption at this time.)
Clearly, there was very little
carry-over effect on leaf-B concen-
trations from treatments in previ-
ous years. All trees had received 1
lb of soil borate in 1986, but in 1987
trees that were in the first two treat-
ments, and thus received no B that
year, contained much lower leaf B
levels than those that received soil
B in 1987. Trees in Treatment 2
received B in 1988 but not in 1989,
and in 1989 their leaf B concentra-
tions fell by 34 ppm. When no tree
received any B in 1990, all trees had
similar B concentrations in their
leaves, the concentration having
fallen as much as 38 ppm.
Therefore, our recommendation that soil B he ap-
plied only every third year apparently does not pro-
vide adequate protection against B deficiency .
Effects of B treatments on fruit B and Ca concen-
trations are shown in Table 3. Fruit B concentra-
tions tended to reflect leaf B concentrations. Thus,
all soil treatments increased fruit B similarly, and
considerably more so than did foliar B treatments.
Furthermore, there was little effect of B applications
except in the years of treatment.
It has been suggested at times that since B
affects movement of Ca in plants, high rates of B
application might be desirable to increase fruit Ca
levels. In 1987 and 1988, B treatments had no effect
on fruit Ca, but in 1989 soil B treatments signifi-
cantly increased fruit Ca levels. Since B application
rates were the same each year and both leaf and fruit
Table 3. Effects of boron treatments on
B and Ca concentrations (ppm) in Mcintosh
apple fruit tissue.
Treatment
1987
1988
1989
(see Table 1)
B
Ca
B
Ca
B
Ca
1
15
127
24
101
61
127
2
20
126
74
103
46
126
3
78
134
77
110
72
135
4
78
133
84
104
74
144
5
71
122
85
111
75
142
6
26
128
32
108
36
119
7
39
132
41
109
52
128
Fruit Notes, Spring, 1991
11
Table 4. Effects of boron treatments on fruit characteristics of Mcintosh
apples. 1988.
Firmness (lbs)
Treatment
in 1988
Starch
score*
Harvest
Storage
NoB
3.8
15.8
9.2
1 1/3 lb borate/tree
5.9
17.6
10.0
1 lb borate/tree
5.6
16.1
10.0
1 1/3 lb borate/tree
5.0
16.5
10.4
1 2/3 lb borate/tree
5.0
16.6
10.1
2 x 1/2 lb Solubor/100 gal.
5.6
16.5
9.5
2 x 1 lb Solubor/100 gal.
4.9
16.6
9.9
'Score of 1 to 3 = immature;
score of 4 to 6 =
= mature; score
of 7 to 9 =
overmature.
B levels were similar
each year for an annual
treatment, it appears
that any beneficial ef-
fect on Ca from high
rates of B application is
dependent on environ-
mental conditions in a
given year, and cannot
be depended upon.
It is widely recog-
nized that when B con-
centrations in apples
are too high, early rip-
ening is promoted. By
chance, the block of
trees we chose for this
experiment contained
relatively high B levels
without any treatment.
Leaf B levels of 35 to 50 ppm are considered to be
optimum, and the lowest level measured in this ex-
periment was 42 ppm (Table 2). All treatments
except the 1/2 lb Solubor sprays raised levels above
the optimum range. Thus, it is important to observe
the effects of these treatments on fruit quality.
In 1987, heavy premature fruit drop occurred
from many trees, and measurements of fruit remain-
ing on the trees indicated that the soil borate treat-
ments had accelerated fruit ripening. In 1988, fruit
were systematically sampled, and all B treatments
resulted in higher starch disappearance scores
(riper fruit) than in the treatment that received no B
that year (Table 4). These results were confirmed in
1989, and data from ethylene measurements were
consistent with those from the starch assessments
(data not shown). Therefore, our results showed
that when leaf B was raised above the optimum level,
fruit ripening was accelerated.
Curiously, despite the accelerated ripening,
these high-B fruit were firmer than ones whose B
was within the optimum range (Table 4). This was
evident both at harvest and after storage for 4
months in 32°F air. These results were confirmed in
1989 (data not shown). This has been reported
before, although the reason for the greater firmness
is not known. While the greater firmness is certainly
desirable, the premature drop due to accelerated
fruit ripening precludes any thought of deliberately
overdosing with B to improve fruit firmness.
The results of this experiment indicate that our
recommendation that a soil application of borate or
borax be applied every third year is not adequate
protection against B deficiency in apples, and that
the recommendations for 1/2 lb of Solubor per 100
gallons of spray is not equivalent to a soil B treat-
ment.
These results also show the importance of know-
ing the B status of apple trees through annual leaf
analyses . If trees have optimum B levels, then
premature fruit drop (along with a waste of money)
can be caused by application of an unneeded B
treatment. However, if trees are deficient in B — as
thev often are in the Northeast — then annual B
applications are needed to ensure strong tree growth
and good fruit quality.
It appears that the recommendations for B treat-
ments to apple trees that are being made by Dr.
Warren Stiles at Cornell University are more appro-
priate than the ones that we have been making.
Therefore, his recommendations are presented as
follows.
Very low leaf boron (less than 25 ppm). Apply 2
to 3 lbs of actual B per acre to the soil, plus , apply
3 sprays of Solubor at 1 lb/100 gallons dilute
equivalent at tight cluster to pink/white bud;
again at 7 to 10 days after petal fall; and again at
25 to 30 days after petal fall.
Low leaf boron (25 to 34 ppm). Apply 2 to 3 lbs
of actual B per acre to the soil, plus , apply 2
sprays of Solubor at 1 lb/100 gallons dilute
equivalent at tight cluster to pink/white bud,
and again between 10 and 30 days after petal
fall.
Leaf boron in optimum range (35 to 50 ppm).
Continue present B program.
High leaf B (greater than 50 ppm) . Discontinue
use of B for one year, and resample. Be alert for
premature drop or occurrence of storage disor-
ders due to early fruit ripening.
12
Fruit Notes, Spring, 1991
Second-level Apple IPM
Ronald J. Prokopy, Daniel R. Cooley, William M. Coli,
Wesley R. Autio, Margaret M. Christie, and Kathleen P. Leahy
University of Massachusetts
Background
Integration in pest management practices for
agricultural crops may occur at several different
levels. There may be: at LEVEL 1, integration of
multiple management tactics for a single class of
pests (arthropods, diseases, vertebrates or weeds);
at LEVEL 2, integration of multiple management
tactics across all classes of pests; at LEVEL 3, inte-
gration of combined management approaches across
the entire system of crop production; and at LEVEL
4, integration of concerns of all those having vital
interest in pest management — growers, research-
ers, extension personnel, private consultants, ag-
chem industry, consumers, environmentalists, and
government regulatory agencies.
Within first-level IPM, we consider there to be 2
stages of advancement. The first-stage involves use
of multiple integrated approaches for determining
need and optimum timing of application of a single
technique of pest control: treatment with pesticide.
Under first-stage, first-level IPM in orchards, the
thrust is upon development and use of effective
techniques for monitoring pest entry into orchards
and pest abundance, as well as upon monitoring
various weather conditions for predicting likelihood
of pest establishment and growth. First-stage, first-
level IPM practices have been in effect in many
Massachusetts apple orchards since 1978. The sec-
ond-stage involves integrated use of multiple tech-
niques of pest control (not simply pesticide) for a
single class of pests. For arthropods, this stage
entails employment of cultural, behavioral, and bio-
logical methods, as well as pesticides. Second-stage,
first-level IPM practices have been in effect in a few
Massachusetts apple orchards since 1987. Results of
first- and second-stage practices have been reported
in several issues of Fruit Notes over the past decade.
The general success of first-level IPM practices
in terms of production of high quality fruit with sub-
stantially less use of pesticide has prompted us to
embark in 1991 on a 3-year pilot program of evalu-
ating second-level IPM tactics in selected Massachu-
setts apple orchard blocks. Until now, integration of
new approaches for managing arthropods, diseases,
weeds, or vertebrate pests has occurred only within
a discipline — not across all of these disciplines.
Under second-level IPM, we would be aiming at
integrating the most advanced cultural, biological,
behavioral, and pesticidal approaches to pest man-
agement across all classes of apple pests — insects,
mites, diseases, weeds, and vertebrates. To support
this study, we have received 3 years of funding from
the Massachusetts Society for Promoting Agricul-
ture, the Northeast Regional IPM Program, State
and Federal IPM program sources, and the Massa-
chusetts Fruit Growers' Association.
In the great majority of orchards in which we
have conducted first-level IPM trials to date, fruit
quality and yield at harvest have been equal to or
better than those under normal grower practices. In
a few orchards, however, excessive injury to fruit or
foliage has occurred. Hence, there is no guarantee
that second-level IPM protocols will be foolproof and
will not in some cases (hopefully very few) result in
abnormal fruit injury.
The following is a description of our planned pro-
gram for full second-level IPM practices and our
planned program for transitional second-level IPM
practices commencing in April, 1991.
Full Second-level IPM Practices
A. Insects:
(1) Application of 3 to 4 selective insecticide
sprays from April to early June to manage plant
bugs, sawflies, plum curculios, fruitworms, early-
season leafrollers, first generation codling moths,
lesser appleworms, leafminers, and leafhoppers. No
use of any insecticides after early June.
(2) Removal of unmanaged apple and pear trees
within 100 yards of each block to reduce immigration
of codling moth and lesser appleworm.
(3) Placement in late June of odor-baited, red-
sphere visual traps every 5 yards on perimeter apple
trees to intercept immigrating apple maggot flies.
Traps will be cleaned of insects twice (July and
August) and removed in September. Initially, the
"killing agent" on these traps will be a sticky sub-
Fruit Notes, Spring, 1991
13
stance from which alighting flies cannot escape.
Pending further advancement and EPA approval,
the sticky will be replaced by a mixture containing
pesticide, a fly-feeding stimulant, and a residue
extending agent to kill alighting flies.
(4) Following harvest, removal of dropped
apples from the orchard floor to preclude buildup of
wi thin-orchard populations of codling moths, lesser
appleworms, and apple maggot flies that could de-
velop to maturity on infested dropped apples. In
addition, on blocks of mature trees we will employ
root pruning following bloom using a sharpened
subsoiling blade mounted on a tool bar to promote
earlier reddening of apples and possibly delayed rip-
ening, thereby reducing the probability of prema-
ture fruit drop (in the absence of Alar) and succeed-
ing buildup of codling moths, leafrollers, and apple
maggot flies in dropped fruit.
(5) A biological control approach to manage-
ment of aphids and summer generations of leaf-
rollers, leafminers, and leafhoppers by permitting
buildup of natural enemies of these pests in an
orchard environment free of insecticides after early
June.
B. Mites:
(1) Application of oil (safe on beneficial organ-
isms) in April to control overwintering red mite eggs.
No further application of miticide.
(2) Sowing seeds of 4 species of broadleaf plants
(clover, plantain, white cockle, and nightshade) to
establish a groundcover that will harbor two-spotted
mites. Predatory Amblyseius fallacis mites (raised
from a strain that is resistant to insecticides used
from April to June and purchased from BIOKON,
Inc.) will be released in the groundcover in June,
where they will be allowed to build on two-spotted
mites as prey and then move up into the apple trees
to provide effective biological control of European
red and two-spotted mites. To prepare for sowing
seeds of broadleaf weeds in September, herbicide
will be applied in May the length of each tree row in
2 bands, each extending from the tree trunks out-
ward to 2 meters. The seeds will be sown into these
bands after the herbicide-treated sod has been
lightly cultivated by a side-mounted weed badger.
C. Diseases:
(1) Use of a flail mower to chop fallen apple
leaves in November in combination with application
of urea sprays to fallen leaves to enhance leaf litter
decay and reduce the substrate necessary for over-
wintering Venturia ascospores to develop and infect
trees in the following spring. Leaves may also be
chopped in the spring, thereby further disrupting
ascospore maturation. These activities also hold
promise of reducing numbers of leafminer pupae
overwintering in fallen leaves, thereby providing
multiple benefit from integrating disease and insect
control tactics.
(2) Assess potential ascospore dose (PAD) in
autumn and spring to permit tailoring the timing of
the first needed fungicide treatment against apple
scab the following spring according to PAD level.
Ascospore maturity in 4 geographic regions will also
be evaluated in the spring, using microscopic exami-
nation of squash mounts, to guide adjustments in
making the first fungicide application.
(3) On-site monitoring of temperature, leaf
wetness and humidity conditions in each block to
permit precise determination of apple scab infection
and fine adjustment of needed fungicide sprays
following the first scab treatment. The materials
used against primary-season (i.e. ascospore-initi-
ated) scab infections will be principally demethyla-
tion-inhibiting (DM3) fungicides at rates which will
control scab at 10- to 12-day intervals following the
initial application. Using this strategy, fungicide
use is minimized in terms of both numbers of appli-
cations and amounts of fungicide per acre, as com-
pared to other fungicide strategies. Secondary scab,
if it develops, will be managed using fungicides
which are not destructive to predatory mites.
(4) Summer pruning of all trees in July and
early August to open the tree canopy, thereby alter-
ing the microclimate within the canopy and thus
reducing infection by sooty blotch and fly speck, and
perhaps some other summer diseases. This practice
will promote earlier and more extensive fruit colora-
tion, and provide integration of a disease, a horticul-
tural, and an insect management practice by allow-
ing earlier harvest and reduced chance of fruit drop
(as mentioned, populations of apple maggot and
some other insects can build from dropped fruit).
D. Weeds:
Mowing once per month from May to October be-
neath the tree canopy as well as in the alleyways
between trees. Blade height will be adjusted to
permit maintenance of about 15 cm of growth of
broadleaf plants that support mite predators be-
neath the canopy. Mowing on this schedule will
lower the humidity in the understory, and may
thereby reduce sooty blotch and fly speck infections.
Mowing in October will deter mice from invading.
14
Fruit Notes, Spring, 1991
E. Vertebrate Pests:
In blocks where sampling indicates injury from
bird pecks has reached 0.5%, Scare-Eye™ balloons
will be attached to poles and hung 14 meters apart
above the tree canopy. Because bird injury is usually
confined to trees near the block perimeter, only
perimeter rows will have balloons. In blocks where
deer injury to apple buds is determined to be a
problem, a bar of Cashmere Bouquet™ soap will be
hung from every perimeter tree. Every tree will
receive a wire guard around the trunk to prevent
rodent injury. The last mowing of the year in
October will be close to the ground (mite predators
will have already entered the soil to diapause). If
these techniques, in combination with dropped fruit
removal, are not enough to prevent rodent establish-
ment, toxic zinc phosphide bait will be applied to
observed mouse entry holes beneath canopies in
November.
Transitional Second-level
IPM Practices
Transition toward full second-level IPM in-
volves use of practices that are more advanced and
integrated than first-level IPM practices but less
advanced and integrated than full second-level IPM
practices. Hence, most but not all practices used
under full second-level IPM will be used here. These
are the differences.
(1) Treatment of perimeter apple trees with in-
secticide every 3 weeks from early June through
mid-August as a substitute for using interception
traps for apple maggot flies.
(2) No root pruning to promote early fruit red-
dening and reduce premature fruit drop.
(3) No seeding of broadleaf plants and resultant
establishment of a groundcover favorable for mite
predators and no release of predatory mites.
(4) No use of a flail mower and urea treatment
in November to chop fallen apple leaves to reduce
apple scab inoculum and overwintering leafminer
pupae.
(5) No use of Scare-Eye™ balloons to repel
birds.
Conclusions
Food safety will undoubtedly continue to be a
major issue in the minds of the public during the
1990's. There may well be new pressure from regu-
lating agencies to reduce the level of detectable
pesticide residue on harvested fruit (especially fruit
to be consumed by infants and, by implication, chil-
dren) to extremely low or essentially zero amounts.
This reduction could call for cessation of spraying
pesticide after a certain point in the growing season,
perhaps has early as June. If this turns out to be the
case, we must be fully prepared to employ a proven
set of cultural, biological, and behavioral manage-
ment tactics that together are a substitute for pesti-
cide use beyond mid-season. We anticipate that by
evaluating a second-level IPM approach from 1991
through 1993, we will produce a coherent and effec-
tive set of practices that will be cost effective and bio-
logically effective as a substitute for pesticide use
after early June. Moreover, these practices would be
environmentally safe and tend to promote long-term
build-up of beneficial natural enemies of pests.
Fruit Notes, Spring, 1991
15
Scare-eye™ Balloons for Controlling
Flocking Birds in Orchards
Ronald J. Prokopy
Department of Entomology, University of Massachusetts
Flocking birds such as crows, starlings, and
bluejays may cause serious injury to tree fruit,
especially as fruit approach harvest. Bird-pecked
fruit not only represent a loss for fresh-market sale
but also are very inviting to yellow-jackets and other
hornets that pose a threat to pickers. Although I
have no data to back up this generalization, my
impression is that fruit become particularly suscep-
tible to bird injury (1) as they begin to show red, (2)
as they begin to taste sweet, (3) when they are
nearby woods or hedgerows, and (4) when there has
been little or no recent rainfall. Various sorts of au-
ditory and visual deterrents have been used in an
attempt to reduce bird injury to fruit. From 1988
through 1990, 1 evaluated the effectiveness of Scare-
Eye™ balloons (Pest Management Supply Co.) for
this purpose in my own 50-tree orchard of disease-
resistant cultivars on M.26 rootstock in Conway,
MA. Scare-Eye balloons originated in Japan and ap-
parently are repellent to flocking birds on the basis
of the decorations on the balloon surface which are
thought to represent an exaggerated version of the
eye of a predator such as an owl. An abbreviated
account of results in my orchard for 1988 and 1990
was given in Fruit Notes 55(4):9-14. Here is a fuller
account of results from 1988 through 1990.
To obtain an estimate of the distance over which
a single balloon might repel birds, in 1988 1 hung one
balloon above the center tree of the orchard and
sampled fruit at harvest for bird injury on each of the
49 surrounding trees. Trees were on M.26 rootstock
and were spaced at 4 yards intervals within rows and
6 yards intervals between rows. The balloon was
filled with air and was suspended from a pole so as
to be about 1 yard above the top of the tree canopy.
It was emplaced in mid-August, when the first bird-
pecked fruit were found and was removed near the
end of harvest.
From 1985 through 1987, bird damage to fruit
averaged 12.2%, more than twice as great as all dam-
age by insects and diseases combined. Thus, bird
pressure in the vicinity of the orchard was very high.
In 1988, fruit on trees about 6 yards from the balloon
had only 1.5% bird injury compared with 11.7%
injury to fruit on trees about 12 yards away and
20.6% injury to fruit on trees about 18 yards away.
From these results, it appeared that a Scare-Eye bal-
loon could indeed be very effective in repelling
crows, starlings, and bluejays (the main fruit-dam-
aging birds in my orchard) over a distance of at least
6 yards.
Based on the 1988 results, in 1989 and 1990 I
hung one Scare-Eye balloon every 12 yards, figuring
6 yards worth of protection on all sides. Results over
the entire orchard were most encouraging: only 0.4%
bird injury in 1989 and 0.9% in 1990. Once the
balloons were emplaced in mid-August, they were
not handled until they were removed after harvest.
In sum, these findings suggest that Scare-Eye
balloons can be very effective repellents to crows,
starlings, and bluejays in apple orchards. Some an-
ecdotal reports indicate that yellow balloons are the
most effective, white next, and black least effective.
Other anecdotal reports suggest the opposite trend.
I used a mixture of colors in 1989 and 1990 and
cannot comment usefully on color-associated effec-
tiveness. However, mini-tests did reveal to me that
effectiveness does depend strongly on hanging a bal-
loon well above the top of the tree canopy and free to
blow in the wind. Balloons hung at the perimeter of
a tree canopy but not above it are not effective. Be-
cause flocking birds are adept at learning, it proba-
bly is a good idea not to emplace any balloons until
fruit damage occurs. While Scare-Eye balloons may
repel crows, starlings, bluejays, and possibly black-
birds effectively, they may prove to be less effective
against robins, orioles, and some other birds. Fi-
nally, even though a 12-yard distance between bal-
loons proved very effective in my small apple or-
chard, a greater or lesser distance between balloons
might be more appropriate under other circum-
stances.
16
Fruit Notes, Spring, 1991
Efficient Use of Sterol-inhibiting
Fungicides: Questions and Answers
About the Delayedl 0-day Program
Roberta Spitko
New England Fruit Consultants, Lake Pleasant, MA
Daniel Cooley
Department of Plant Pathology, University of Massachusetts
Planning apple fungicide schedules
in the 90's.
Even though apple growers have had consider-
able success reducing fungicide use, the key to
commercially successful disease management re-
mains efficient fungicide use. Yet trying to develop
a plan for apple fungicide use in the 1991 season is
a little like trying to keep an old car running. Just
when you have one part fixed, another part breaks
down. There are several management "parts" that
impact a fungicide program: scab, summer diseases,
mites, insects, costs, regulations, and public con-
cerns. And of course, good disease management is
just a part of the real goal, growing a profitable apple
crop. This year, many growers will consider using
sterol inhibiting fungicides (specifically Nova™ and
Rubigan™). In this article, we give a set of guide-
lines for the most efficient and effective use of these
fungicides. Unfortunately, there are no blanket
recommendations for using sterol inhibitors. Each
grower's situation is different, and each year is
different. The best recommendation we can give to
all growers is to study the pluses and minuses of each
option. Then when you need advice, ask for it.
Why do people call these fungicides Si's?
The sterol inhibiting (SI) fungicides are a new
type of chemical, and they act in a much different
way than the standard protectant fungicides. Sis
are a valuable new asset, but they bring with them
a new set of management problems.
Actually, there are several names for this type of
fungicide: demethylation inhibitors (DMIs), ergos-
terol biosynthesis inhibitors (EBIs), or sterol inhib-
itors (Sis). While the other terms indicate more
precisely what these fungicides do, the term SI is
most commonly used, and we use it here. Specifi-
cally, in this article we mean the two apple scab
fungicides, Nova (myclobutanil) and Rubigan (fe-
narimol). Funginex™ (triforine) and Bayleton™
(triadimefon) also are Sis registered for apples, but
Funginex is a less effective scab fungicide than Nova
and Rubigan, and Bayleton does not have any sig-
nificant effect on scab.
Can I use these fungicides for 96 hrs
of kickback, the way I used captan to
get 18 hrs kickback?
One of the most remarkable features of the new
SI fungicides is long-term curative or post-infection
effectiveness. When the Sis were first introduced,
apple growers were already familiar with the 18 to
24 hrs of "kickback" activity given by protectants
such as captan and the EBDCs. In addition, they
were familiar with the eradication properties of
Benlate™ (benomyl), Topsin-M™ (thiophanate-
methyl), or Cyprex™ (dodine). Yet the Sis were
promising 3 and 4 days of post-infection activity.
Unfortunately, researchers, manufacturers, and
growers jumped to the conclusion that this type of
post-infection activity was essentially the same as
"kickback," i.e. when an SI was applied within the
prescribed 96 hrs from the start of an infection, that
application would always stop the targeted infec-
tion. This assumption was rudely contradicted by an
event in Michigan. Rubigan was used in a single ap-
plication very early in the season to control a serious
infection period. A long dry period followed, during
which no fungicide was applied. After about a
month, growers discovered scab lesions in their or-
chards. It became evident that while a single post-
infection application will usually eradicate an infec-
tion, there are circumstances when it will stop it only
temporarily. At least two post-infection SI applica-
Fruit Notes, Spring, 1991
17
tions are needed to insure that an apple scab infec-
tion is stopped.
This is a key difference between Sis and the
other apple fungicides. To use the Sis effectively, it
is important to know such differences, and to under-
stand a little about the way Sis work.
Why do people stress slow drying
and careful application with the Sis?
Unlike captan, mancozeb, or the benzimi-
dazoles, the Sis are poor protectants. They do not
form a barrier on the outside of the leaf. Instead,
they act on fungi growing within leaf tissue, killing
the fungal cells by disrupting cell wall formation. So
the Sis must be absorbed by the leaf tissue to be
effective. After absorption, there is little if any
fungicide redistribution on the leaf surface. After a
few hours, the fungicide is almost completely ab-
sorbed by the leaf. Any fungicidal activity then takes
place within the leaf.
As a result, for adequate fungicide action, good
absorption is essential. The spray solution needs to
be on the leaf as a solution for at least 1 hr and
preferably 2 hrs if it is to be absorbed adequately.
There are a few conditions which can reduce ade-
quate absorption.
■k Fast drying, as might occur in the heat of a dry
day, can decrease SI uptake.
•k If the spray solution is washed from the leaf
soon after application, it will not be absorbed
adequately. Applying Sis in a rain, or just
before a rain, will not be effective.
* Thorough coverage during application is
more critical with Sis than with other fungi-
cides. For one thing, Sis are used at very low
rates, compared to the 4 to 6 lbs per acre per
application used with materials like man-
cozeb or captan. For Nova the total applica-
tion for the entire season may be only 1 lb,
while for Rubigan it may be 1 qt. Since Sis are
not broadly redistributed to uncovered areas
of tissue, it is important that tissue be well-
covered with the correct concentration during
the spray application.
Getting an effective fungicide dose into the leaf
is critical. To work, an SI must cover all the exposed
tissue, and be absorbed at a rate which will kill any
growing scab fungus. If the rate is too low, it will not
kill the fungus. The margin for error with Sis is
much smaller than with the protectant fungicides.
Cutting rates below the recommended minimum,
either intentionally or by mistake, will lead to con-
trol problems.
But why should I have to worry
more about coverage and rates with
the Sis than I did with the fungicides
I used to use?
These days, taking care to put the correct
amount of pesticide where you need it is very impor-
tant, regardless of whether it is an SI or anything
else. However, compared with Sis, the standard
protectant fungicides offer superior redistribution,
generally affect a broader disease spectrum, and
permit growers to make small calibration or applica-
tion mistakes without disastrous results. For ex-
ample, if there is some small, unknown problem
preventing even coverage with a protectant, the
next rain will spread out the fungicide. In addition,
as many growers know, cutting the label rate of
mancozeb by 10%, or even 50%, generally will pro-
vide effective scab control. Protectant fungicides are
more "forgiving" than the Sis .
Rate errors with the Sis are much more critical.
First of all, when dealing with ounces per acre rather
than pounds per acre, it is easier to make a 10%, 20%,
or 30% error in weights. Second, our tests and field
experience indicate that failures of an SI appear first
on the fruit. Dr. David Rosenberger, plant patholo-
gist from the New York State Agricultural Experi-
ment Station, shows that 1 lb per 100 gal of captan
will lead to 4 times as much terminal scab as fruit
scab, while Nova at 1 oz per 100 gal will lead to 15
times as much fruit scab as terminal scab. So if too
low a rate, or bad coverage, lead to scab problems,
those problems will often occur where they hurt
most: on the fruit.
Will Sis affect more than just scab?
Sis must be considered as part of an overall apple
disease management program. Generally, they are
effective against scab, mildew, and rust. Other
diseases, such as frog-eye leaf spot and blossom-end
rot, are not controlled by Sis. The Sis are of little or
no use on summer diseases such as sooty blotch,
flyspeck, black rot, and bitter rot. In order to control
these diseases, Sis must be mixed with fungicides,
like the protectant mancozeb. However, it is not
clear whether or not early-season mancozeb reduces
diseases which show up in the summer, and whether
or not using Sis alone will cause an increase in the
summer diseases.
18
Fruit Notes, Spring, 1991
Should I be concerned about scab
becoming resistant to the Sis?
Originally, plant pathologists thought that scab
would become resistant to the Sis, leading to si-
tuations like those seen with Benlate and Cyprex.
Cases of scab resistance in the field have been
observed in Europe and Canada. To reduce the
potential for the development of resistance to scab is
one reason why we have recommended using the Sis
with a contact fungicide. However, the thinking
regarding SI resistance has changed over the past
year. First, places where resistance has developed
have a history of multiple SI applications for the
entire season over a number of years. Second, hot
temperatures seem to trigger the development of
resistance in scab. In a wild, untreated scab popula-
tion, many more resistant isolates are present late in
the season than early in the season. Third, the
mixing of an SI and a broad-spectrum protectant
may not be any more effective in curtailing the
development of resistance than the practice of using
a limited number of Sis and then switching to the
broad-spectrum fungicides. Considering these fac-
tors, it may be advisable to use Sis alone during
primary season, for 3 to 5 applications, and use a
captan program during the summer. Given the al-
ternatives and the relatively low risk of resistance
developing, the Sis used at a moderate rate (9 oz/A
for Rubigan and 4.5 oz/A for Nova) are a good choice
and will manage scab well. In general, primary-
season use of higher rates of the Sis alone for no more
than 2 applications should present no more resis-
tance pressure than using a marginally effective
protectant with the SI.
Is mixing an SI with a protectant
still a good idea?
Havingjust read that mixing is not necessary for
resistance management, do not forget all the other
good reasons for using a protectant. We recommend
a protectant, particularly captan, be used with the SI
as a deterrent to fruit scab. The protectant will also
ensure good fungicidal activity over 8- to 10-day
intervals. Protectant fungicides boost the weak
protectant ability of an SI to about 5 to 7 days.
Combined with the 4-day post-infection activity of
the SI, growers can use 10-day schedules confi-
dently. Insecticide and fungicide applications can be
combined more easily, saving trips through the or-
chard. In the past, if growers chose to use Sis, they
generally used the 10-day approach in New England
and combined an SI with mancozeb. However,
without the EBDCs, we have had to reevaluate the
combination approach.
If I should not cut rates, and can
only save lor2 applications on a
10-day schedule, is there some other
way to save applications?
It was clear that growers might use 1 or 2 fewer
fungicide applications with the Sis on a 10-day
schedule, compared to using other fungicides on a 7-
day schedule; however, SI programs remained rela-
tively expensive. Recently, we have made further
efforts to reduce the number of SI applications
needed in a season. We did this by delaying the
initial fungicide application made in a season. There
were two basic reasons behind the development of
this approach. (1) Long-term suppression of scab
symptoms. As research on the Sis continued it
became apparent that as long as SI applications were
made before actual symptoms from an infection
appeared, there was a good chance that the infection
could be eradicated. While it was best to stay within
the 4-day post-infection period, it was possible to go
well beyond that time-frame and still get control, as
long as the fungus had not broken out and started to
produce spores. Because of cool temperatures in
early spring, several weeks may be required before
lesions from a particular infection period will erupt
through the leaf surface. This provides a wide
window during which SI fungicides may be applied
to arrest developing infections. (2) The inoculum
dose factor. At the same time, William MacHardy,
David Rosenberger, and David Gadoury proposed
that early-season scab inoculum in a commercial
orchard may be so low as to be insignificant. Since
only a small proportion of the total scab inoculum for
a season is mature at the beginning of the year, and
there is very little if any scab in a commercial
orchard, there should be virtually no inoculum in
most commercial orchards at the beginning of the
scab season. As shown in Figure 1, it takes a few
weeks from the time the first few mature spores are
visible, or from green tip, to reach a point where 5%
or more of the spores have matured and been dis-
charged. Suppose there were 10,000 ascospores per
square yard in an orchard. As of April 20, five
hundred would have been released, and probably
created problems. But suppose only 10 ascospores
per square yard were available. Then only 1/2 a
spore (on average) would have been released by
Fruit Notes, Spring, 1991
19
100
Percent
of Season's
Ascospores
Released
50 -
t.c. pink bloom p.f.
Mar 25 Apr 14 May 4 May 24
Date (growth stage)
Jun 13
Figure 1 . Venturia ascospore maturity by date in 1990 at Wilbraham, MA, showing the stage of tree development
and the point at which significant levels of scab were first present (5%) and the point at which the season ended
(95%).
April 20, and this level probably would create no
infections. In this example, the released spores hit
10% at pink and 20% at bloom. At this point, the risk
of infection becomes important. But, in low inocu-
lum orchards, there is little risk of infection up to this
point.
The question of inoculum from wild hosts has not
been answered fully. MacHardy and his associated
suggest that inoculum from outside the orchard is
not important. For purposes of the delayed SI
program, this suggestion appears to hold true.
Based on this scab inoculum theory, and on the
SI effect on pre-symptom scab, it seems likely that
the first scab fungicides of the season could be
applied much later than is usually done. Such a
schedule might eliminate one or more early-season
applications.
How would this strategy for using the
Sis actually be done in an orchard?
In 1987, we began the implementation of the 10-
day, delayed-SI program in commercial orchards
and research plots, using a total of approximately 50
acres. Fungicides were withheld until the tight
cluster or pink stage of development, regardless of
apple scab spore maturity or the number of infection
periods which had occurred. Once begun, the appli-
cations were made as close to 10-day intervals as
possible. The SI fungicides were always applied in
combination with a protectant fungicide, for reasons
described earlier. Rates and intervals were adjusted
to account for differences in disease pressure when
necessary. In all cases, a minimum of 2 applications,
and preferably 3, were made after the first applica-
tion, for a total of 3 to 4 Sl/protectant sprays during
the primary scab season. When the interval from a
major infection period extended to more than 4 days,
we recommended a higher SI rate, tightening the in-
terval between the first and second post-infection
spray to 7 days, or both. In general, the delayed 10-
day SI program was successful, and in later years
more acres have been grown using the schedule.
Have the rules changed since the
early 10-day delay trials?
We stress that each season and each grower
required slight modifications to fit individual situa-
tions. In an attempt to be comprehensive and guide
growers in making individual decisions, we devel-
oped a flow chart based on phenological development
to guide SI applications. However, this chart proved
to be confusing to many growers. As a result, we
arrived at a simpler set of rules, and used individual
consultations to deal with individual situations.
20
Fruit Notes, Spring, 1991
Each program is based around the following rules.
•k Orchards with economic scab levels (1% or
higher) in the previous season should not
delay, or should be treated with a fall benzimi-
dazole spray.
*At about 5% ascospore maturity, or tight clus-
ter to pink, whichever comes first, start the SI
program. Use 2 oz/100 gal Nova or 4 oz/100 gal
Rubigan plus 1/2 rate of dodine or captan (de-
pending on oil use) in the first application.
* Repeat applications, using 1.5 oz/100 gal Nova
or 3 oz/100 gal Rubigan plus 1/2 rates of protec-
tants, at as close to 8- to 10-day intervals as is
practical, and apply a minimum of 3 treat-
ments.
*If the 10-day interval is exceeded, particularly
when scab pressure is high and occurs when
protective/post-infection activity is minimal,
then two consecutive applications should be
made 7 days apart.
■frAfter 95% of the ascospores have been dis-
charged, at about 1/4-inch fruit, the SI pro-
gram should stop. However, if there is a heavy
infection period between the last SI applica-
tion and 95% discharge, an additional SI
application should be made.
How did the loss of the EBDCs
affect what was done in the delayed
10-day program?
When the EBDC fungicides became unavailable
in 1990, options for early-season disease control
became extremely limited. As a result, growers
looked to the Sis even more than they had previ-
ously.
On the surface, it might seem possible to have
replaced the EBDCs with captan; however, the in-
compatibility of captan with oil is a critical impedi-
ment to making the substitution. Oil applied as late
as pink is essential to IPM mite management, savi ng
multiple miticide applications in the summer. Since
it is necessary that between 2 and 3 weeks elapse
between an oil application and a captan application
to avoid phytotoxicity, captan is of little use in
primary season scab management. Cyprex is an-
other option against apple scab, though fungal resis-
tance is known to be present in numerous sites
throughout New England. As a result, growers in
1990 were faced with using an inferior protectant,
either with or without the Sis, or using the Sis alone.
Generally, growers chose to use an SI, but whether
or not they used a protectant, and what type of
protectant they used, varied.
Given all the changes, how did the
program work last year?
Several thousand acres of apples were grown
under a 10-day, delay-SI program in 1990. Scab
pressure generally was heavy, with at least 2 Mills'
infection periods occurring each week from April 15
through the end of primary season. According to
squash-mount evaluations, ascospores were mature
in all areas by the last week in April. By the time of
the first fungicide applications, spore discharge in
all areas ranged between 8% and 20%, as estimated
from samples at 4 sites throughout the state. Fun-
gicide applications were difficult to make, because
Table 1. Orchards using
delayed 10-day SI program in 1990.
Interval between
Ascospores (%)
applications (days)
Inoculum
rating
First Number of SI
application applications
Fruit scab
(%)
Mature
Discharged
Mean
Maximum
Low
30
20
Pink (5/1)
2
9
9
0.2
Low
20
15
Loose cluster (5/1)
3
10.5
11
0.2
Low
16
8
Loose cluster (5/1)
4
10
12
0.0
Moderate
30
20
Pink (5/1)
4
10
11
1.2
Moderate
30
20
Pink (5/1)
4
11
11
0.8
Moderate
20
15
Loose cluster (5/1)
4
10
11
0.3
Moderate
16
8
Loose cluster (5/1)
4
10
12
0.1
High-
16
8
Tight cluster (5/4)
3
10.5
10
0.2
High*
20
15
Loose cluster (5/1)
4
10
13
0.0
*These orchards treated
with a benzimidazole at the end of the previous season.
Fruit Notes, Spring, 1991
21
winds were frequently high.
As shown in Table 1, the delayed 10-day SI
program was very effective in controlling primary
scab in orchards with low or moderate scab inocu-
lum. The amount of scab inoculum in most orchards
was estimated the previous season using quick vis-
ual evaluations of foliage and observing scab at pack
out. If scab was obvious in the block, or exceeded 2%,
then the orchard was considered to have high inocu-
lum. Otherwise, inoculum was judged to be low.
/ have heard that if I wait 7 days
on either side of an oil application, I
can apply captan. Will that work
with the SI program?
Unfortunately, there are no good rules for inter-
vals between captan and oil applications. Try to
maximize the interval between oil and captan by
making somewhat earlier oil applications, and using
other fungicides early in the season. For example,
use Cyprex or SI alone early around oil, and save
captan for later. If you have a real need to use
captan, a 7-day or even 14-day interval may or may
not be enough. There are no hard data. The ad-
vantages of captan have to be weighed against un-
certain risks of phytotoxicity.
If I want to use an SI program, do I
have to use captan or some other
protectant with it?
Use SI alone only if necessary to avoid the
captan/oil problem. It is most important to use
captan around bloom and early fruit set as a protec-
tant against fruit scab. So use SI alone earlier rather
than later. Use higher rates or
closer intervals when you do.
/ had a lot of fruit scab
last year
using the Sis. Given that,
and
their expense, why
should I use them?
egy, these problems generally could be traced to
application mistakes.
Application problems which lead to scab are
caused by too little SI being absorbed into tissue.
There are several potential reasons for an inade-
quate application, at least on parts of a tree:
* Trees too thick or too tall, so coverage is inade-
quate in some parts;
■^Alternate row sprays resulting in too low a
rate per acre;
*Low volume applications made in poor condi-
tions, such as wind, rapid drying, and poor
calibration;
*Rain within 2 hours of the application washing
off material;
^Continuous rain, making mid-season applica-
tions impossible; and
* Exceeding the 10-day interval, with a major
infection at the end of the interval, and not ap-
plying 2 sprays 7 days apart.
With large trees, or where spray coverage is not
even or complete, the Sis may be a poor choice. If you
are not comfortable with and knowledgeable about
the differences between Sis and standard fungi-
cides, you may want to avoid them. However, the 10-
day interval and the initial delay offer schedule flexi-
bility, and when used well these materials are very
effective. Cost and fruit scab must be kept in mind,
but both can be controlled. While there was fruit
scab in many orchards last year, it was not limited to
orchards using Sis. In many other cases, Sis on a de-
layed 10-day schedule produced a very clean crop in
a very tough scab year.
In general, we felt that the
Sis on the delayed 10-day sched-
ule performed very well. How-
ever, as shown in Table 1, some
growers did exceed acceptable
levels of scab. Rather than find-
ing problems with the basic strat-
Table 2. Different blocks, with increasingly long delays for the first
application of fungicide, showing that even in low-inoculum or-
chards, delays can lead to economicly important levels
of scab.
Fungicide applications were Rubigan 1.6 EC at 6 oz/acre plus
captan 50 WP at 3 lbs/acre.
Interval from
Time of first Number of
previous
Scab
application application
application (days)
(%)
Tight cluster (4/27) 4
-
Late bloom (5/7) 3
10
Fruit set (5/18) 2
11
10
1/2-inch fruit (5/28) 1
10
27
22
Fruit Notes, Spring, 1991
What happens if I delay too long? may absorb enough SI to eradicate infection, but the
~ , . , . , . , j . fruit will not. Adding an adjuvant/penetrant has
Delaying too long "» a high- to moderate-inocu- been ed ^ increase gI actiyi Qn fmit
lum orchard can also lead to problems For example, Tbm ^ bfi new tions about SIs this r
data from one orchard (Table 2) show that even ina n ,. , , „ ,.„
, , , u 11 i. 11 u Growers, consultants, and researchers are all still
low-inoculum orchard, scab will eventually become . , ' llt _' ...
severe if treatments are delayed too long. ] f min e abo ^ the SI f " n &i«des. In our experience,
The first evidence of an SI control failure gener- these fungicides offer a valuable new tool for apple
ally will be limited to fruit, with virtually no associ- disease management, and can be used in a way that
ated foliar lesions. This failure is thought to be due compliments IPM strategies. Cost may remain an
to the decreased uptake of SI fungicides by the waxy issue, though the 10-day delayed schedule offers an
fruit cuticle. If coverage is borderline, leaf tissue option for keeping expenses down.
Fruit Notes, Spring, 1991 23
Fruit Notes
University of Massachusetts
Department of Plant & Soil Sciences
205 Bowditch Hall
Amherst, MA 01003
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354
Fruit Notes
repared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension.
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
^\
ISSN 0427-6906
I 9!
51
Volume 56, Number 3
SUMMER ISSUE, 1991
Table of Contents
BIOLOGICAL
Influence of Groundcover on the Incidence of
n Yole Activity and Damage in Apple Orchards
Effects of Rootstocks on Apple Ripening
iRRARY Early Performance of Summerland Red
SCIENCES UBKAKT Mcintosh on Various Rootstocks
Soil Moisture Affects the Performance of Mcintosh Apple Trees
on M.7A M.26. M.9/MM.106. and M.9/MM.111 Rootstocks
New England Fruit Meetings & Trade Show
Removing Abandoned Apple Trees Near Orchards:
Time Required and Potential Benefits
The Liberty Apple: Ripening and Storage Properties
Seasonal Light Requirements in a Fruit Orchard
/P
Fruit Notes
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July, and October by the Department of Plant & Soil Sciences, University
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opportunity in programs and employment.
Influence of Groundcover on the
Incidence of Vole Activity and Damage
in Apple Orchards
James A. Parkhurst
Department of Forestry & Wildlife Management,
University of Massachusetts
In the course of normal feeding activities,
both meadow voles (Microtus pennsylvanicus)
and pine voles (M. pinetorum) are capable of
inflicting substantial physical injury on apple
trees by girdling the lower trunk or stripping the
protective covering from lateral roots. Even
where inj ury to trees is not immediately evident,
a reduction in fruit yield or tree vigor may
indicate the presence of vole activity. Because
any loss of production represents a potential
economic impact, orchardists have been search-
ing for practical methods to control or prevent
vole damage. In many cases, the method of
choice has been the application of rodenticides in
an attempt to reduce the size of the vole popula-
tion. However, with increasing costs for materi-
als and labor plus added pressure from a "more
aware" general public demanding use of only
environmentally sensitive techniques, applica-
tion of broadcast rodenticides has come under
scrutiny. The use of cultural control techniques
is receiving renewed interest and some on-going
investigations are beginning to produce some
fascinating results. A paper recently prepared
by researchers at Cornell University (Curtis, P.
D. and I. Merwin. 1990. Meadow vole activity
and damage to apple trees in relation to orchard
ground cover management. Proc. 52 nd Annual
New York State Pest Management Conference,
Cornell University, Ithaca, NY. 9 pp.) examines
the influence of different groundcovers and
mulches on vole activity and feeding damage to
apple trees. This article summarizes some of the
findings of their research.
Methods
When the Cornell experimental orchard ini-
tially was established in 1985, Empire and
Jonagold trees on MM.lll rootstocks were
spaced three yards apart and a groundcover of
70% Elka ryegrass (a dwarf perennial), 30%
Ensylva red fescue, and a starter crop of oats
was planted beneath the trees. In this study,
researchers examined vole activity and damage
on 2.5-yard-wide plots established within the
dripline of trees and using eight experimental
groundcovers (treatments), including:
(1) existing sod groundcover, treated with
glyposate 2.5 yards wide;
(2) same as above, but only 1.5 yards wide;
(3) live crownvetch;
(4) bare or nearly bare ground following
multiple herbicide treatments;
(5) sod mixture of red fescue and perennial
ryegrass mowed to consistent height of 2
to 5 inches;
(6) sod mixture (as in #5), but unmowed
and treated with growth suppressant
and selective herbicides;
(7) hay/straw mulch 6 inches thick, renewed
annually; and
(8) clean soil maintained by monthly roto-
tilling to a depth of 4 inches.
Metal mouse guards (12 inches high) were
placed 2 inches deep on all trees and normal
winter applications of zinc phosphide (bait and
broadcast) were continued on all plots from 1986
Fruit Notes, Summer, 1991
MOWED SOIL GLY2.5 UNMOW TILLED GLY 1.5 CRNVCH HAYSTW
GROUNDCOVER TYPE
Figure 1. Percent of plots with evidence of vole activity (as determined by the apple activity
index) for 8 groundcover treatments at the Cornell Orchard, Ithaca, NY. Key to
groundcovers: MOWED = mowed sod; SOIL = bare soil; GLY 2.5 = glyphosate-treated sod,
2.5 yards wide; UNMOW = unmowed, but treated sod; TILLED = clean tilled soil; GLY 1.5
= glyphosate-treated sod, 1.5 yards wide; CRNVCH = crownvetch; and HAYSTW = hay/
straw mulch.
through 1988 to keep the number of voles in
check. Researchers never attempted to deter-
mine the total number of voles on the site but
instead relied on indices of their presence. Evi-
dence of vole presence and activity (e.g.,
feedings, runs, tunnels, nest sites) within each
groundcover type was monitored and extent of
damage was estimated. In 1990, all application
of rodenticide ceased and vole activity was as-
sessed using an apple activity index and feeding
index. These techniques both involve examin-
ing apple slices placed in runs for evidence of
feeding by voles (i.e., tooth marks).
Results
Highest levels of vole activity were found on
plots covered by crownvetch and by hay/straw
mulch; whereas, rototilled, mowed sod, and bare
soil strips were infrequently used by voles.
Feeding damage by voles on apple trees also was
more extensive under crownvetch (field-wide
average of 40% injury) and hay/straw mulch.
Based on apple slice indices, 100% of the apple
bait stations placed in hay/straw mulch and 96%
of those placed in crownvetch were visited by
voles; activity at bait stations was lowest in
mowed sod, bare soil, and 2.5-yard herbicide-
treated strips (Figure 1).
Discussion
Based on the results of this study, it is clear
that groundcovers need not be edible to be of
importance to voles. In fact, the structural
qualities of a groundcover (i.e. the escape or
hiding cover it provides) appear to be of equal, if
not greater, importance to these animals than
the food potential such groundcover may offer.
Hay/straw mulch was not used as food yet it
provided excellent cover under which voles
would be concealed while feeding. Similarly,
crownvetch provide a thick, protective canopy
under which voles could move about without
Fruit Notes, Summer, 1991
detection and with little fear of predators. Also,
previous reports had indicated that crownvetch
was unpalatable or toxic to voles; however,
evidence of voles feeding on its shoots and leaf
stems (but not on leaves) was found in this
study.
On many of the plots treated with
glyphosate, a somewhat homogeneous layer of
low-growing mosses developed and, although
vole activity was still noted, damage was nearly
non-existent. Also, only an average of 76% of the
so-called "bare soil" plots were devoid of vegeta-
tive cover. Hardy and persistent "weedy" plants
were able to colonize these plots despite herbi-
cide treatment, yet a consistent canopy of cover
never developed; this apparently prevented or
substantially hindered vole use of those plots.
Based on the results of their study, Cornell's
researchers recommend that growers should
consider incorporating a manipulation of
groundcovers (i.e. establishing mowed sod, bare
soil, or, to a lesser degree, 2.5-yard-wide
glyphosate-treated strips) in their integrated
approach (e.g., tree guards, rodenticide applica-
tion) to minimizing damage caused by voles.
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Effects of Rootstocks on Apple Ripening
Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
It is important that factors which can alter
the time of fruit ripening be identified. Those
factors which are under grower control may be
used to expand the harvest season of a single
cultivar if the magnitude of the effects is great
enough and if the effects are consistent. Al-
though, some of these factors are not under the
control of the grower, knowledge of the effects
should help growers manage their harvest sea-
son. Several studies have observed effects of
rootstocks on apple ripening; however, because
of problems with the studies, it is very difficult
to make a clear statement on the nature of these
effects. In 1986, 1 began a study of the effects of
rootstocks on ripening in the 1980/81 NC-140
Cooperative Roots tock Trial at the University of
Massachusetts Horticultural Research Center
in Belchertown. I reported results from the first
two years in Fruit Notes 52(2):5-10. Since then,
two more years of data have been collected, and
a new trial has begun.
The first trial was with Starkspur Supreme
Delicious trees on Ott.3, M.7 EMLA, M.27
EMLA, M.9, MAC 9, and OAR 1. They were
planted in 1980 and 1981 as part of the NC-140
Regional Project. Four fruit were harvested
from the periphery of each tree periodically
throughout the harvest season in 1986-89. Af-
ter harvest, the internal ethylene concentration
of each apple was measured. These data were
used to determine a date when the average
ethylene concentration of the fruit on a tree was
greater than 1 ppm, representing the approxi-
mate time of the beginning of ripening. Addi-
tionally, each year 10- fruit samples were har-
vested from each tree for firmness, soluble sol-
Fruit Notes, Summer, 1991
ids, watercore, and starch analysis.
The dates of the beginning of ripening are
presented in Figure 1 . The effects of crop on fruit
ripening were eliminated in the statistical
analysis, since roots tock can alter crop load
substantially, and crop load has a dramatic
effect on fruit ripening. Means in Figure 1 have
been adjusted appropriately. There was a great
deal of variation in the date of ripening from
year to year; however, a few relationships were
consistent. Generally, fruit from trees on M.27
EMLA and Ott.3 ripened earlier than average,
and fruit from trees on M.7 EMLA and OAR 1
ripened later than average. The difference be-
tween the earliest and the latest ripening
ranged from only a few days in 1989 to 17 days
in 1988. Firmness, soluble solids, watercore,
and starch data are not presented but they were
consistent with the results presented in Figure
1, which are based solely on ethylene produc-
tion.
The second trial utilized Summerland Red
Mcintosh on M.7A, M.7 EMLA, Ott.3, and M.26
EMLA planted in 1985 at the Horticultural
Research Center. Samples were taken for ripen-
ing studies in 1989 and 1990. Sample size and
sampling procedure for internal ethylene analy-
sis were similar to those described above.
Figure 2 depicts the date of the beginning of
ripening of fruit from trees on these four
roots tocks. As in the first trial, the effects of crop
load were removed. Generally, the results ob-
M.7 EMLA
OAR 1
MAC 9
M.9
Ott.3
M.27 EMLA
V///////////A
sWWWN
V///////A
1988
VZ& 1987
■H 1988
^ 1989
Y///////A
'////////A
9/20 9/25 9/30 10/5 10/10 10/15 10/20
Figure 1. The relative date in 1986-89 of the beginning of ripening (date when the average
internal ethylene level reached 1 ppm) of apples from Starkspur Supreme Delicious trees
on various rootstocks planted in 1980 and 1981.
Fruit Notes, Summer, 1991
M.7 EMLA
M.7A
M.26 EMLA
Ott.3
YZ& 1989
■■ 1990
9/22
9/24
9/26
9/28
9/30
Figure 2. The relative date in 1989-90 of the beginning of ripening (date when the average
internal ethylene level reached 1 ppm) of apples from Summerland Red Mcintosh trees on
various rootstocks planted in 1985.
tained with Delicious were confirmed with
Mcintosh, i.e. M.7A and M.7 EMLA appeared to
delay ripening, and Ott.3 appeared to advance
ripening. The magnitude of the differences,
however, was not large. These trees were only
in their fifth and sixth leaf, so at least two years
of additional data will be required to confirm
these responses.
The results presented here, along with those
presented in the last issue of Fruit Notes
[52(2):8-9] on the 1984 NC-140 Trial, give some
indication of the relative effects that rootstock
can have on apple ripening. Furthermore, it is
obvious from the data in Figures 1 and 2 that the
effects are not consistent in their magnitude. I
do not believe that rootstock can be used reliably
to expand the harvest season; however, it is
valuable for growers to realize that in some
years there can be very dramatic responses.
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Fruit Notes, Summer, 1991
Early Performance of Summerland Red
Mcintosh on Various Rootstocks
Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
A number of articles in Fruit Notes have
reported the results from apple rootstock trials,
particularly those established by the NC-140
Technical Committee on Rootstocks. Several
years of reliable data have been accumulated on
Mark, Ott.3, M.9 EMLA, Bud.9, P.2, P.22, C.6,
etc.; however, all of these trials have used Deli-
cious as a scion. Clearly, in New England we are
not greatly concerned with Delicious, and the
1989 Apple Survey showed that the acreage of
Delicious in New England is declining dramati-
cally.
To study performance of various rootstocks
using a more appropriate scion for New En-
gland, a trial was established in 1985 at the
University of Massachusetts Horticultural Re-
search Center in Belchertown using
Summerland Red Mcintosh on M.9/Alnarp 2,
Ott.3, M.7 EMLA, M.26 EMLA, M.7A, OAR 1,
and Mark. The soil is a Montauk fine sandy
10
Trunk cross-sectional area (in )
M.9/A.2
Ott.3
M.7 EMLA M.26 EMLA
M.7A
OAR 1
Mark
Figure 1. Trunk cross sectional area after the 1990 growing season of Summerland Red
Mcintosh trees on various rootstocks planted in 1985. Bars with any letter in common are
not significantly different at odds of 19:1.
Fruit Notes, Summer, 1991
loam, which is classified as a sandy or gravelly
soil with a tendency to drought.
Tree growth has been relatively good, and
Figure 1 depicts the trunk cross-sectional area of
trees on the various rootstocks. Trees on M.7
EMLA were the largest in the planting, and
those on Mark were the smallest. In this trial
there seems to be a difference between M.7
EMLA and M.7A. This difference has not been
reported elsewhere, but here trees on M.7A were
significantly smaller than those on M.7 EMLA
after six growing seasons. Trees on Mark are
small in this planting, probably not much larger
than trees on M.9 would be if included in the
trial.
Yield began in the fourth leaf (Figure 2). In
1988, trees on Ott.3, M.7 EMLA, and Mark
produced the most fruit per tree. In 1989, trees
on M.7 EMLA, M.7A, Ott.3, and Mark were the
most productive. In 1990, trees on Ott.3 and M.7
EMLA continued to be the most productive.
Trees on Mark produced very few fruit in 1990,
partly because of overproduction based on tree
size in 1988 and 1989. Trees on Mark appear to
have "runted out" to some degree; therefore,
corrective measures will have to be taken to
rejuvenate them in the next few years.
Yield efficiency (Figure 3) relates yield per
tree to tree size and gives a rough means for
comparing potential production per acre. On a
cumulative basis for 1988-90, Ott.3 resulted in
the most efficient tree in the planting. Trees on
Mark were less efficient than those on Ott.3, but
were significantly more efficient than trees on
M.9/Alnarp 2, M.7 EMLA, M.26 EMLA, M.7A,
or OAR 1. Trees on OAR 1 were the least
efficient in the planting, producing only a small
number of fruit in 1988, 1989, and 1990.
140
Yield per tree (lbs)
120 -
100
80
BO
40
20
w
Mill 1990
EZ3 1989
^B 1988
± -
§
////
vzzzzzz
M.9/A.2
Ott.3
M.7 EMLA M.26 EMLA
M.7A
OAR 1
Mark
Figure 2. Yield per tree (1988-90) of Summerland Red Mcintosh trees on various rootstocks
planted in 1985. Bars with any letter in common are not significantly different at odds of
19:1.
Fruit Notes, Summer, 1991
.2
36
30
24
18
Yield efficiency (Ibs/irT TCSA)
f^^
M.9/A.2
Ott.3
M.7 EMLA M.26 EMLA
M.7A
OAR 1
Mark
Figure 3. Cumulative yield efficiency (1988-90) of Summerland Red Mcintosh trees on
various rootstocks planted in 1985. Bars with any letter in common are not significantly
different at odds of 19:1.
Trees in this trial are only 6 years old, so
ultimate performance cannot be determined
yet; however, at this point trees on Ott.3 are
performing the best. The tree size is somewhat
smaller than those on M.26 EMLA, and effi-
ciency is twice that of M.9/Alnarp, M.7 EMLA,
M.26 EMLA, or M.7A Mark produced a very
efficient tree early in its life, but problems with
overproduction have weakened its potential for
production over the next few years. M.26 EMLA
did not perform any better than M.7 in this trial,
which is a surprising result. M.7 EMLA and
M.7A produced trees which were similarly effi-
cient but significantly different in size.
Other trials recently planted or planned will
study performance of new rootstocks with culti-
vars of importance to the New England apple
industry. A trial was planted in 1990 at the
Horticultural Research Center which compares
M.9 EMLA, Bud.9, and M.26 EMLA, using
Marshall Mcintosh as a scion. A cooperative
trial with James Schupp at the University of
Maine was established in 1991 at the Horticul-
tural Research Center and Highmoor Farm
(Monmouth, ME) which compares Marshall
Mcintosh, Rogers Red Mcintosh, Chic-a-dee
Mcintosh, and Pioneer Mac on Mark, M.27
EMLA, M.7 EMLA, and M.26 EMLA. Another
cooperative trial with James Schupp is planned
for 1993 that will compare P.2, P. 16, P.22, M.27
EMLA, M.9, Bud. 146, Bud.469, V605-1, V605-
3, Burgmer 984, Burgmer 756, Burgmer 751, T-
337, and Pajam I using Summerland Red Mcin-
tosh, Cortland, and Macoun as scions. Another
NC-140 trial is also scheduled for 1993 which
will include eight new rootstocks from the
Cornell breeding program. Liberty will be the
scion cultivar.
Fruit Notes, Summer, 1991
Soil Moisture Affects the Performance
of Mcintosh Apple Trees on M.7A,
M.26, M.9/MM.106, and M.9/MM.111
Rootstocks
Wesley R. Autio, William J. Lord, and Peter L. M. Veneman
Department of Plant & Soil Sciences, University of Massachusetts
Apple trees on a given rootstock often per-
form differently on different orchard sites.
Likely, the predominant site factors governing
these differences in performance are soil charac-
teristics. To maximize productivity, growers
must choose the rootstock best suited to their
soil conditions. Few studies have specifically
evaluated the relationship of rootstock perfor-
mance and a soil characteristic, so this study
was initiated to relate performance of four
rootstocks and soil moisture.
Ten sites were selected throughout Massa-
chusetts with a range of soil drainage character-
istics from somewhat excessively drained to
poorly drained. Locations of the sites and the
soil types are given in Table 1. Marshall Mcin-
tosh trees on M.7A, M.26, M.9/MM.106, and
M.9/MM. Ill were planted at the 10 locations in
1982. Red Chief Delicious/M.7A was included
for pollination. All trees received similar fertili-
zation. Weed-free strips (6 ft) were maintained
in the tree row using herbicides. All trees were
Table 1. Soil characteristics at the 10 locations utilized in this study. Drainage class
abbreviations:
SED = somewhat excessively drained; WD =
well drained;
MWD =
moderately well drained; SPD :
= somewhat poorly drained; PD =
poorly drained
Depth to
seasonal
Depth to
high water
Soil
Orchard
hard pan
table Drainage
series
location
Soil texture
(in)
(in)
class
Chatfield
Pepperell
fine sandy loam
26
>26
SED
Charlton
Charlton
fine sandy loam
>35
>41
WD
Shelburne
Colrain
fine sandy loam
20
>30
WD
Whethersfield
Wilbraham
fine sandy loam
35
>41
WD
Shelburne
Shelburne
fine sandy loam
27
>34
MWD
Pittstown
Harvard
silt loam
20
20
MWD
Scituate
Belchertown
fine sandy loam
24
20
MWD
Buckland
Shelburne
fine sandy loam
15
15
SPD
Stissing
Groton
silt loam
21
18
SPD
Cabot
Colrain
fine sandy loam
18
10
PD
Fruit Notes, Summer, 1991
Trunk cross-sectional area (in 2 )
SED
WD MWD
Drainage class
SPD
PD
Figure 1. Trunk cross-sectional areas after 7 growing seasons of Marshall Mcintosh trees
on M.7A, M.26, M.9/MM.106, and M.9/MM.111 planted in 1982. Drainage class: SED =
somewhat excessively drained; WD = well drained; MWD = moderately well drained; SPD
= somewhat poorly drained; and PD = poorly drained.
trained to central leaders utilizing minimal dor-
mant pruning. Yield and tree size data were
collected annually through 1988.
Soils were grouped by their drainage class
for presentation of the results. One soil was in
the somewhat excessively drained (SED) cat-
egory; three soils each were in the well drained
(WD) and moderately well drained (MWD) cat-
egories; two soils were in the somewhat poorly
drained (SPD) category; and one soil was in the
poorly drained (PD) category. This grouping
provides an approximation of the soil moisture
levels present among the sites.
The effects of soil and rootstock on tree size
were significant (Figure 1). Trees grew best on
the WD and MWD soils and poorest on the SED
and PD soils. This result suggests that tree
growth is affected dramatically by soil moisture,
with the driest and wettest soils producing the
least growth. To obtain maximum productivity,
a grower must be aware of the size potential of
trees in their soil. On sites where growth is
expected to be low, trees should be planted close
together, and on sites where growth is expected
to be high, trees should be planted farther apart.
The spread after the 1988 growing season of
trees on M.7A, for instance, varied from 13 ft on
the MWD soils to 8 a on the SED soils. Clearly,
10
Fruit Notes, Summer, 1991
optimal yields per acre would not be obtained if
trees were spaced 13 ft apart on the SED soils.
Regardless of soil moisture level, trees on
M.7A were the largest, and those on M.26, M.9/
MM. 106, andM.9/MM.lll were similar in size
and significantly smaller than those on M.7A.
In a practical sense, growers can assume that
the relative vigor of rootstocks will be the same
on most soil types.
The effects of soil moisture on tree growth
are not as important as effects on yield. Figure
2 presents the cumulative yields (1986-88) for
each rootstock in the 5 soil groupings. In
general, trees yielded the most on the WD and
MWD soils and the least on the SED and PD
soils. The interesting result, however, was the
relationship among the rootstocks. On the dri-
est soils (SED and WD) the largest trees, those
on M.7A, outyielded trees on M.26, M.9/
MM.106, or M.9/MM.111. On the wetter soils
(MWD, SPD, and PD), however, trees on M.7A
yielded similarly to the smaller trees, those on
M.26, M.9/MM.106, or M.9/MM.111.
Yield per tree is only part of the picture.
Yield efficiency (lbs of fruit per square inch of
trunk cross-sectional area) relates yield per tree
to tree size and is a way to compare relative yield
potentials per acre, the much more important
determinate of performance. Figure 3 presents
the cumulative (1986-88) yield efficiencies of
Yield per tree (bu)
SED
WD MWD
Drainage class
SPD
PD
Figure 2. Cumulative yields per tree (1986-88) of Marshall Mcintosh on M.7A, M.26, M.9/
MM.106, and M.9/MM.111 planted in 1982. Drainage class: SED = somewhat excessively
drained; WD = well drained; MWD = moderately well drained; SPD = somewhat poorly
drained; and PD = poorly drained.
Fruit Notes, Summer, 1991
1 1
Yield efficiency (lbs/in 2 TCSA)
MWD
Drainage class
Figure 3. Cumulative yield efficiencies (1986-88) of Marshall Mcintosh trees on M.7A, M.26,
M.9/MM.106, and M.9/MM.111 planted in 1982. Drainage class: SED = somewhat
excessively drained; WD = well drained; MWD = moderately well drained; SPD = somewhat
poorly drained; and PD = poorly drained.
trees on each rootstock in each soil grouping.
Overall, the most efficient trees were on the WD
and MWD soils; however, dramatic differences
existed among rootstocks. Trees on M.7A were
the least efficient on all soils, with a gradual
decline in efficiency as soil moisture increased
from the WD to the PD categories. The trees on
M.26, M.9/MM.106, and M.9/MM.111 were
similarly efficient on the SED, WD, and MWD
soils, and trees on M.26 and M.9/MM.106 were
the most efficient and similarly efficient on the
SPD and PD soils. As the soil moisture increased
beyond the MWD category, the trees on M.9/
MM. Ill declined in efficiency.
These results lead to several conclusions.
M.26 and M.9/MM.106 produced the most con-
sistently efficient tree, across all soils. In fact,
these two rootstocks produced trees which did
not decline in efficiency as the soil moisture
increased beyond the WD category. This result
must be qualified, however, since both M.26 and
MM. 106 are very sensitive to collar rot, which is
prevalent in wet soils. Over eight years, this
study did not show significant numbers of either
of these rootstocks lost to collar rot; however,
more time will be required to assess longevity
adequately on the wettest soils. It would be best
to avoid these two rootstocks on SPD and PD
12
Fruit Notes, Summer, 1991
soils, and on other soils M.26 would be the most
desirable, since it generally costs less than the
double- worked tree, M.9/MM.106.
M.9/MM.111 was included in the study be-
cause of the reputed wide adaptability of the
MM. Ill root. It provided no advantage over
M.9/MM.106 on the driest soils, and it per-
formed very poorly on the wettest sites. These
results, along with the results of other studies
showing the excessive suckering potential of
M.9/MM. Ill, suggest that it is not a reasonable
selection, regardless of soil conditions.
M.7A provided little advantage on any soil,
since it did not produce a yield efficient tree;
however, M.7Ais less sensitive to collar rot than
M.26 or MM. 106 and likely would survive longer
in wet soils. On the other hand, because of the
poor efficiency of M.7A, it may be more cost
effective on wet sites to correct the drainage
problem and use M.26 as a rootstock, than to
plant inefficient trees.
Acknowledgements
The authors would like to thank Dave
Shearer, Harvey and Marvin Peck, Bud and
Barry Wiles, Tony Lincoln, Dorrance Greene
and Steve Smedberg, Frank and Bruce Carlson,
Ed O'Neil, and Tony Rossi for the use of their
land and their cooperation with this project.
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New England Fruit Meetings
& Trade Show
The New England Fruit Meetings & Trade
Show are sponsored annually by the tree fruit
grower organizations of New England, the New
England University Cooperative Extensions,
and the New York & New England Apple Insti-
tute. Each year, a two-day educational program
is presented, including a variety of topics in
horticulture and pest management. The trade
show runs concurrent to the educational pro-
gram and has from 90 to 100 exhibitors. In 1992,
the meetings will be held on January 22 and 23
at the Sheraton Host Hotel (same place as in
1989, 1990, and 1991; however, the facility has
changed its name). Future dates include Janu-
ary 20-21, 1993, January 19-20, 1994, January
18-19, 1995, January 17-18, 1996, and January
22-23, 1997. For further information on the
program contact Wesley Autio (413-545-2963),
or on the trade show contact Robert Smiley ( 508-
422-6595).
Fruit Notes, Summer, 1991
13
Removing Abandoned Apple Trees
Near Orchards: Time Required
and Potential Benefits
Ronald J. Prokopy and Jennifer Jaros
Department of Entomology, University of Massachusetts
As we move toward implementation of sec-
ond-level IPM, increasing emphasis will be
placed on habitat management as a type of
cultural control to reduce or eliminate need of
pesticide use against certain pests. A principal
habitat management practice is removal of
abandoned or wild, unsprayed apple trees in the
vicinity of orchards. As we reported in Fruit
Notes [56(1):16-17], cutting down all unsprayed
apple trees within 100 yards of the perimeter of
apple orchard blocks provides outstanding con-
trol of second-generation codling moths. The
100-yard distance simply seems too far for most
codling moth females to fly. Because abandoned
apple trees are major hosts of plum curculio and
sawfly and because, like codling moth females,
neither of these pests is a strong flier, there is
good reason to believe that removing abandoned
apple trees within 100 yards of the orchard
perimeter might substantially reduce immigra-
tion and injury caused by these pests.
This brief report provides information on the
density of abandoned apple trees within 100
yards of 12 Massachusetts commercial apple
orchard blocks and the time required to find and
cut down all such trees. Four of the blocks were
in western Massachusetts, 4 in the central part
of the state, and 4 in the eastern part. All were
6 to 8 acres in size.
The average number of abandoned apple
trees found within 100 yards of each block was
57 (range: to 352). For 6 of the blocks, there
were 31 or fewer such trees. On average, 50% of
the area around a block was woods, brush, or
open field, habitats in which abandoned apple
trees were found. The other 50% of area con-
sisted of adjacent commercial orchard blocks.
The average amount of time it took for two
people armed with chain saws to scout thor-
oughly the woods, brush, and open field and cut
down all abandoned apple trees around a block
was about 1.5 hours.
In conclusion, it seems to us a most worth-
while investment of about 30 minutes per acre to
search out and remove abandoned apple trees
within 100 yards of commercial apple blocks. It
could pay high dividends in reducing pressure
from such rather host-specific pests as codling
moth, sawfly, and plum curculio. It probably
will not help with apple maggot, however, as the
flies can easily travel many hundreds of yards to
orchards. It can be done at any time of year,
though accurate tree identification may be easi-
est during the growing season, especially during
bloom. The only constraint lies in ownership of
the land and willingness of neighbors to be
sympathetic if you are not the owner.
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14
Fruit Notes, Summer, 1991
The Liberty Apple: Ripening and
Storage Properties
Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
Joseph F. Costante
Department of Plant & Soil Science, University of Vermont
Environmental and food safety concerns
about the use of pesticides to maintain the
production of high quality apples have resulted
in a great deal of research with the goal of
reducing pesticide applications. Additionally, a
significant breeding effort has been underway
for a number of years to produce apple cultivars
which are resistant to the major fruit diseases.
One such cultivar, Liberty, was bred at the New
York State Agricultural Experiment Station in
Geneva and was released in 1978. Liberty is
resistant to apple scab, cedar apple rust, fire
blight, and powdery mildew. Because of its
quality and the heightened concerns about pes-
ticide use, New England growers have become
very interested in Liberty as a commercial cul-
tivar. In fact, a recent survey suggested that it
would be the fifth most planted cultivar in New
England through the first half of the 1990's, a
remarkable achievement for a cultivar that was
not planted at all in the first half of the 1980's.
Unfortunately, very little information is
available about the horticultural characteris-
tics of Liberty, and very importantly, little is
known about the ripening and storability of the
fruit. The objective of the work reported here
was to obtain some baseline information about
Liberty ripening and how best to store the fruit.
Harvest-season Changes
For maturity studies in 1988-90, Liberty/
M.7A trees planted in 1980, and Empire/M.26
trees planted in 1975 at the University of Mas-
sachusetts Horticultural Research Center
(HRC), Belchertown, were used.
Each year, harvests were made periodically
throughout the harvest season. The internal
ethylene concentration of each fruit was mea-
sured, the percent surface red color of each fruit
was assessed, the weight was determined, flesh
firmness was measured, and the soluble solids
(sugar) content was evaluated. Fruit were also
cut equatorially, dipped in an iodine-potassium
iodide solution, and rated for starch loss.
Figures 1 through 3 depict how quality and
ripening of Liberty and Empire fruit changed
during the harvest season. Generally, Liberty
fruit were smaller than Empire fruit, but this
difference likely was related to crop load. When
the firmness difference was significant, Liberty
fruit were firmer than Empire fruit during the
harvest season, even after the effects of fruit
weight were removed. In most years, the soluble
solids content of Liberty fruit was higher than
that of Empire fruit, and Liberty fruit generally
were more highly colored than Empire.
Informal taste evaluations suggested that
the appropriate beginning date of harvest for
these two cultivars was similar, September 30,
approximately one week before Delicious; how-
ever, measurement of internal ethylene concen-
trations showed that Liberty is a peculiar culti-
var, in that internal ethylene levels exceeded
one ppm (the normal level associated with the
initiation of ripening) as much as two weeks
prior to the apparent optimal beginning date of
harvest. It seems unlikely that Liberty fruit
should be harvested that early. The problem
with this situation is that it makes accurate
assessment of fruit ripening very difficult, since
a rise in ethylene content is normally considered
to be the signal that ripening has begun. Alter-
natively, the starch-iodine test may be helpful in
Fruit Notes, Summer, 1991
15
Fruit weight (oz)
4 8/20
wz?
22
Flesh firmness (lbs)
'9/20
a/27
14
Soluble solids (%)
11 1 —
9/20
9/27
100
Red color (%)
10/4
10/11
CuMvar » DMi -
WMgMra
10/4
10/11
CuJCvk I Mini
10/4
10/11
10/11
Internal ethylene (log ppm)
10/11
Internal ethylene > 1 ppm (%)
80
y
60
/
40
y/
20
., — Cu*nr •••
£
20 9/27 10/4 10/
Starch index value
i/20
9/27
10/4
10/11
Figure 1. Weight, flesh firmness, percent red color, internal ethylene concentration, percent
with internal ethylene concentration > 1 ppm, soluble solids content, and starch index value
of Liberty and Empire fruit throughout the 1988 harvest season.
16
Fruit Notes, Summer, 1991
5.7
Fruit weight (oz)
Flesh firmness (lbs)
m
9/29
14
Soluble solids (%)
90
Red color (%)
^
9/29
10*
live
10/6
rxa'
10/6
Internal ethylene (log ppm)
9/16 9/22 9/29 10/8 10/13
100
Internal ethylene > 1ppm (%
2/8 9/15 9/22 9/29 10/6 10/13
Starch index value
5
3
tan-
1
9fl 9/15 9/22 *29 1<y6 10/13
Figure 2. Weight, flesh firmness, percent red color, internal ethylene concentration, percent
with internal ethylene concentration > 1 ppm, soluble solids content, and starch index value
of Liberty and Empire fruit throughout the 1989 harvest season.
Fruit Notes, Summer, 1991
1 7
Fruit weight (oz)
•lir
ClMwr ■ Datana
4V21
W28
10/5
Flesh firmness (lbs)
icvs
13
Soluble solids (%)
CuMMT « Daaana
i/14
4V21
*28
90
Red color (%)
10/5
Internal ethylene (log ppm)
100
Internal ethylene > 1 ppm (%)
Starch index value
10/5 9/14
9/21
9/28
100
U.S. Extra Fancy (%)
10/5
10/5
10/5
CtaM na
Data"*
Cmavar , Daaa -
10/6
Figure 3. Weight, flesh firmness, percent red color, percent U. S. Extra Fancy, internal
ethylene concentration, percent with internal ethylene concentration > 1 ppm, soluble solids
content, and starch index value of Liberty and Empire fruit throughout the 1990 harvest
season.
18
Fruit Notes, Summer, 1991
assessing maturity.
In 1988, the Mcintosh starch chart was used
to assess starch loss from Liberty. The begin-
ning of optimal harvest was when the starch
index level reached 3-3.5. In 1989, because of a
better match of the pattern, the Empire chart
was used for Liberty fruit. Optimal harvest was
when the starch index value reached 4.5. In
1990, a chart specific to Liberty was developed.
This chart has been roughly calibrated with
informal taste evaluations, and under Massa-
chusetts conditions, harvest of Liberty fruit
should begin when the starch index value
reaches 4.5. (The Liberty chart is available from
Wesley R. Autio, 205 Bowditch Hall, University
of Massachusetts, Amherst, MA 01003, at a cost
of $ 1 per copy. Subscribers to the Massachusetts
Extension Fruit Newsletter will receive a copy of
the chart with their subscriptions.)
Storage Studies
For storage studies, the same trees as in the
harvest-season studies were used. In 1988,
apples were harvested from each block at
weekly intervals beginning on September 20
and ending on October 1 1. Flesh firmness was
measured at harvest and after storage at 32°F
until December 14. The firmness of Liberty and
Empire fruit were not significantly different;
however, there were differences among the four
harvest dates. Fruit from the three later dates
softened to a lesser degree than those from the
September 20 harvest.
In 1989, apples were harvested from each
block on September 22 and 29 and October 6.
Flesh firmness was measured at harvest and
after four months of storage at 32°F. Liberty
fruit softened to a lesser degree during storage
than Empire fruit, and those from the latest
harvest softened more than those from the ear-
liest harvest.
After storage, the fruit were kept at 70°F for
14 days, after which the incidences of storage
disorders were assessed. Decay, bitter pit, and
senescent breakdown were more prevalent in
Empire fruit than Liberty fruit. Browncore, on
the other hand, was much more of a problem
with Liberty than Empire. Browncore was
present in between 70 and 90% of the Liberty
fruit after four months at 32°F and 14 days at
70°F.
Considering firmness, bitter pit, decay, and
senescent breakdown, Liberty fruit had supe-
rior storage quality to that of Empire fruit;
however, the incidence of browncore must be
seen as a significant detractor. Browncore is a
sign of chilling sensitivity, and the high inci-
dence of browncore in Liberty suggests that it is
a very chilling-sensitive cultivar and cannot be
kept at 32°F for extended periods of time.
To maximize the length of the marketing
period many growers keep apples for extended
periods under controlled atmospheric condi-
tions. The two types of storage used most
commonly in New England are "hard CA" (32°F,
-3% 2 , and <2% C0 2 ) and "soft CA" (38°F, 3%
2 , and 5% C0 2 ). Generally, cultivars which are
chilling sensitive are kept in soft CA, and those
that are chilling resistant are kept in hard CA
To determine the best type of storage conditions
for Liberty, fruit from the 1988 harvest were
kept in hard or soft C A for 5 or 6. 5 months. After
storage the flesh firmness was measured, and
there was no difference between Liberty and
Empire; however, both cultivars softened less in
soft CA than in hard CA. The 1989 harvest was
kept under conditions similar to those of 1 988 for
5.5 months. Less softening occurred during
hard CA than soft CA storage. Significant
amounts of senescent breakdown developed
only in Liberty fruit after hard CA storage.
Significant amounts of bitter pit developed in
Empire fruit only after soft CA storage, and
significant amounts of browncore developed in
Liberty fruit in both types of CA storage.
It is clear from these results that Liberty
fruit can develop a great deal of browncore in
standard controlled atmosphere storages. It
was surprising to observe large amounts of
browncore even in the soft CA storage, where
the temperature was at a level which usually
precludes the development of browncore. When
a very chilling-sensitive cultivar is kept for ex-
tended periods, however, it may be necessary to
utilize an even higher temperature than 38°F.
Further work must be done to identify a usable
temperature for long-term storage of Liberty
fruit.
Fruit Notes, Summer, 1991
19
Conclusions
These studies have shown that Liberty is an
apple which ripens in late September at a time
similar to Empire. A starch-iodine test will be
necessary to assess maturity accurately. Due to
a high sensitivity to chilling injury, Liberty fruit
did not store well. This sensitivity may mean
that Liberty fruit will have to be stored at higher
than normal temperatures if they are to be kept
for extended periods of time.
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Seasonal Light Requirements in a
Fruit Orchard
James T. Williams
Cooperative Extension, University of Massachusetts
Shading within a fruit tree can have many
effects on tree productivity and fruit quality.
Among the factors it influences are fruit set,
weight, color, and taste. Therefore, growers
need to be aware of its importance, and of the
many ways in which they can influence the
amount of shading that occurs.
A number of excellent studies of shading
have been published in recent years, and this
article will summarize the findings from several
of these: Jackson, J. E. and J. W. Palmer, 1977.
J. Hort. Sci. 52:253-266; Robinson, T. L., E. J.
Seeley, and B. H. Barritt. 1983. J. Amer. Soc.
Hort. Sci. 108:855-861; and Rom, C. R. and B. H.
Barritt. 1989. pp. 42-57. In Intensive
Orcharding. Goodfruit Grower, Yakima, WA.
Shading has different effects at different
times of the year. This fact is illustrated in Table
1, which shows results when Redspur Delicious
apple trees were shaded to the same extent at
three different stages of fruit development.
During the time of cell division (0 to 47 days
after petal fall) shading reduced fruit set by
nearly 50 percent. This reduction was not com-
pensated by increased fruit size, so fruit yield
(total weight) was also reduced by about 50
percent. Shading during this period, however,
had little effect on quality of the fruit at harvest.
Shading in mid-season (47 to 93 days after
petal fall) or late-season (93 to 140 days after
petal fall) had no effect on fruit set, but reduced
average fruit weight, fruit color, and soluble
solids (sugar) content. Early-season shading
may have delayed fruit maturation, as judged
by starch rating, but mid- and late-season shad-
ing appeared to have no effect.
The effects of shading will depend in part on
how much light is available. Under cloudy
conditions, effects may be greater than under
bright, sunny conditions. However, growers
need to manage whatever light is available
under their conditions, and there are a number
of horticultural practices that can be used to do
this. The following suggestions are derived from
the studies cited above, some of which are de-
scribed in an earlier report [Fruit Notes 55(4):8].
1. When fruit spurs are shaded anytime
from bud-break until June drop, fruit set
will be reduced. Dormant pruning must be
20
Fruit Notes, Summer, 1991
Table 1. Shade at different times during the season affects fruit
development of Redspur Delicious/M.7. Derived from Rom, C. R. and B.
H. Barritt. 1989. Light interception and utilization in orchards, pp. 42-
51. In A. B. Peterson (ed.) Intensive Orcharding. Goodfruit Grower,
Yakima, WA.
Shading
treatment
(days after
petal fall)
Fruit weight
Fruit Fruit
set Average Total color
Starch Soluble
rating solids
Percent of control*
0-47
47-93
93-140
54
101
95
116
81
94
48
101
100
100
96
92
115
100
100
87
82
83
*Control is not shaded. Other treatments were give 63% shade during
the time specified (140 days after petal fall = harvest).
conducted to prevent this type of shading in
much of the inner portion of the canopy.
2. Row and canopy arrangement are im-
portant. Rows should be oriented north-
south to optimize light interception
throughout the day. In general, narrow
canopies and short trees will intercept more
light than wide canopies and tall trees.
3. Limb arrangement and angle can influ-
ence penetration of light into the canopy.
Limbs should be angled approximately 45°
to 60° from the trunk. Limbs should be
spaced from 1.5 to 3 feet apart, arranged
spirally around the tree to create light "win-
dows."
4. The tree should be maintained in a coni-
cal shape. Any overgrowth of the top will
reduce light penetration into the canopy.
5. Summer pruning can enhance light pen-
etration during the mid- and late-season
periods. Summer pruning should be per-
formed between July 15 and August 30 for
Mcintosh.
6. Maintenance of high quality leaves is
the only way to ensure optimal light inter-
ception. Damage from nutritional stress,
drought stress, insect feeding, or disease
infection can reduce a leafs ability to absorb
sunlight.
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Fruit Notes, Summer, 1991
21
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
SERIAL SECTION
UNIV. OF MASSACHUSETTS LIBRARY
AMHERST, MA 01003
Account No. 3-20685
-i
Fruit Notes
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension System,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
ISSN 0427-6906
Editors: Wesley R. Autio and William J. Bramlage
Volume 56, Number 4
FALL ISSUE, 1991
Table of Contents
Hurricane "Bob," A Lesson in Tree Support
Some Thoughts on Fertilizing Blueberries Efficiently
Advancements in Second-stage Apple IPM:
Combination of Fruit and Food Odor to Increase
Captures of Apple Maggot Flies on Sticky Spheres
Effects of Fruit Ripening. Cultivar. and
Storage on Apple Maggot Larval Survival
Orchard Soils and Apple Rootstocks
The 1991 Apple Harvest Season In Massachusetts
Toxicity of Fungicides to Apple Pollen
Fruit Notes
Publication Information:
Fruit Notes (ISSN 0427-6906) is published the first day of January, April,
July, and October by the Department of Plant & Soil Sciences, University
of Massachusetts.
The costs of subscriptions to Fruit Notes are $5.00 for United States
addresses and $6.00 for foreign addresses. Each one-year subscription
begins January 1 and ends December 31. Some back issues are available
for $1.50 (United States addresses) and $2.00 (foreign addresses).
Payments must be in United States currency and should be made to the
University of Massachusetts.
Correspondence should be sent to:
Fruit Notes
Department of Plant & Soil Sciences
205 Bowditch Hall
University of Massachusetts
Amherst, MA 01003
COOPERATIVE EXTENSION POLICY:
All chemical uses suggested in this publication are contingent upon continued registration. These chemicals should
be used in accordance with federal and state laws and regulations. Growers are urged to be familiar with all current
state regulations. Where trade names are used for identification, no company endorsement or product discrim ination
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 fry the University of Massachusetts Cooperative Extension, Robert G. Helgesen, Director, in furtherance of
the acts of May 8 and June 30, 1914. The University of Massachusetts Cooperative Extension offers equal
opportunity in programs and employment.
Hurricane "Bob," A Lesson in
Tree Support
Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
During the third week of August Hurricane
Bob swept through the region with winds of
nearly 100 miles per hour. Many trees were
seemingly unaffected, but others were either
snapped off or tipped severely. Probably every
tree in Bob's path was in some way damaged;
however, at least 10,000 trees in Massachusetts
either required straightening or replacement.
The long-term effects of this severe storm will be
with us for many years. Some good, however,
can be derived from this catastrophe; we were
able to take a close look at the stability of the
many tree support systems used for intensive
plantings.
In the September issue of The Great Lakes
Fruit Grower, an article written by Phil
Schwallier details some of the effects of a storm
with winds in excess of 85 miles per hour which
swept through a portion of Michigan in July,
resulting in the loss of 5,000 trees. Several of his
comments very closely parallel my observa-
tions. In Michigan, the most commonly lost
trees were four to five years old, on either Mark
or M.26, and of the cultivars Gala, Northern
Spy, or Jonagold. These trees generally were
supported artificially; however, various tech-
niques were used. Conduit pipe or bamboo
simply bent over and provided no support under
the high winds. Steel fence posts or wooden
posts fared much better than conduit. The use
of a single wire to support trees on Mark was of
no value; trees snapped off, slid down the wire,
and piled up at the end of the row.
In Massachusetts, Hurricane Bob resulted
in a great deal of damage among trees on M.7 in
addition to dwarfed trees. We have known for
many years that M.7 produces a free standing
tree, but it often is not extremely well anchored.
With Delicious as a scion, an experiment termi-
nated after Hurricane Gloria (1985) showed
that trees on M.26 with no artificial support
withstood the effects of Gloria significantly bet-
ter than similar trees on M.7. Granted, Deli-
cious on M.7 is known to be a particularly bad
combination, but other trees on M.7 also appear
relatively weakly anchored.
Among dwarf trees in Massachusetts, Mark
seems to have done poorly, as did Gala on Mark
or M.26; however, it is not possible to separate
this relationship from the type of support system
used. Most of these trees have been planted
within the last five years, and most were sup-
ported by a conduit pipe. Under the severe
strain, the conduit pipe bent very easily and the
tree often snapped at the union. As Phil
Schwallier suggested, Mark produces a chars c-
teristically brittle union, as does Gala with
M.26; however, it is not clear whether or not
these trees would have broken if a more substan-
tial support system was used. Little damage
was seen in three- and four-wire trellis systems
or with more substantial posts.
These observations lead to several recom-
mendations:
1. Conduit pipe should be used for support for
no more than one to two years.
2. If you wish to use conduit pipe, within the
first two years after planting add a support
wire at six to seven feet from the ground,
attached to pressure-treated wooden posts
every 20 to 40 feet. Adding this wire is not
cheap ( as much at $ 1 ,4 00 per acre); however,
losing trees is not cheap either.
3. If individual support with no wire is desired,
you must consider pressure-treated wooden
posts. Three-inch posts seem to be adequate
to provide a high level of support.
Fruit Notes, Fall, 1991
Some Thoughts on Fertilizing
Blueberries Efficiently
Eric Hanson
Horticulture Department, Michigan State University
Blueberries require annual applications of
nitrogen (N) containing fertilizers. Most blue-
berry soils are not able to supply naturally the
quantities of N required for optimum production
and growth. However, growers have a number
of choices to make in designing a fertilizer pro-
gram for their plantings. The most important of
these is deciding which N fertilizer to use and
how much to apply.
Optimum N rates vary a great deal from
farm to farm. Plantings on organic soils may
require only 10 to 30 lbs N/acre because these
soils supply a great deal of N naturally.
Plantings on very sandy soils low in organic
matter may require 80 to 100 lbs N/acre because
these soils supply very little natural N. On
average, blueberry plantings in Michigan per-
form best with 60 to 70 lbs N/acre.
This is a wide range in rates. How can you
be sure your rates are best for your plantings?
Careful observations of the growth, production
and appearance of the bushes is helpful.
Underfertilized bushes generally will not grow
or produce as much. Leaves tend to be small and
pale green in color. They tend to develop fall
colors and drop early. Annual shoot growth is
quite short and fruit production is low. Bushes
receiving too much N are dark green and lush
appearing. This may produce excessive growth,
and surprisingly, fruit production is also re-
duced.
The best way to judge whether your N rates
are appropriate is to collect leaf sample and have
the N concentration analyzed. Nitrogen concen-
trations in blueberry leaves are an accurate
indicator of whether or not bushes are receiving
appropriate amounts of N. For optimum produc-
tion, leaves should contain between 1.6 and
2.2% N. Levels higher or lower than this will
likely reduce yields.
There are many ways to maintain optimum
leaf N levels in a blueberry planting. The
challenge is to do it at the lowest cost. Ideally,
fertilizer should be applied at rates and times
that match the seasonal demand of the bushes.
Bushes probably begin needing N at bud break.
The demand probably increases through June
as shoots are growing most rapidly, and begins
to decline in late July or August as growth
begins to slow. The most efficient fertilizer
program might be one that supplied small
amounts of N beginning at bud break, increased
the supply until perhaps late June, and then
began decreasing the supply thereafter. If this
were accomplished, it is likely that optimum leaf
N levels could be maintained by applying much
less N/acre than is typical today.
The most obvious way to match N applica-
tions with demand is to apply N through a trickle
irrigation system. Injecting fertilizer in this
way provides a large amount of flexibility so that
N can be applied where and when it is needed.
Studies in orchards indicate that growers can
apply half as much N and achieve the same
yields by injecting N compared to standard
broadcast applications. Tom Zabadal and I have
started an extensive study at the Southwest
Michigan Research and Extension Center in
Benton Harbor to compare fertilizer injection to
broadcast applications on blueberries.
What can growers who are not set up to inject
fertilizer do to improve their efficiently and
reduce their costs? Here are some suggestions.
1. Apply fertilizer where most roots are lo-
cated. In most blueberry plantings, roots are
concentrated within the row. This is particu-
larly true in younger plantings. Fertilizer
Fruit Notes, Fall, 1991
3.
applied under the row will likely be absorbed
more efficiently than fertilizer spread be-
tween the rows.
Choose the appropriate N fertilizer. Use
materials containing only ammonium-N.
Nitrate-N is easily leached and lost, and not
efficiently absorbed by blueberries. Blue-
berries are also quite sensitive to high levels
of nitrate. When using urea, remember that
20 to 40% of N may be lost by volatilization
if applied when temperatures are above 80
degrees and no rain or irrigation is available
to move the fertilizer into the soil.
Apply fertilizer to best match the demand of
the bushes. Do not apply fertilizer before
bud break since portions will likely be
leached and lost before the bushes can use it.
Consider splitting your fertilizer into two or
more applications between bud break and
late June. We have found split applications
(half at bud break, half at petal fall) provide
a 10% yieldincrease over a single application
at bud break. This work was conducted on a
soil containing 7 to 9% organic matter.
Multiple applications will be most beneficial
on sandy, low organic soils.
4. Lastly, use leaf analysis to determine how
appropriate current N rates are for specific
plantings. Based on leaf samples submitted
to MSU each year, there is a significant
percentage of plantings which are receiving
too much fertilizer. The easiest way to
identify these plantings is through tissue
analysis.
Fertilizer is a significant production cost, so
improving the efficiency of fertilization pro-
grams is prudent economically. Inefficient prac-
tices which result in fertilizer residues in rivers,
lakes or groundwater are a growing concern.
For this reason efficient use of fertilizers is
environmentally prudent as well.
This article was reprinted from The
Great Lakes Fruit Grower, September,
1991.
Fruit Notes, Fall, 1991
Advancements in Second-stage Apple
IPM: Combination of Fruit and Food
Odor to Increase Captures of Apple
Maggot Flies On Sticky Red Spheres
Jian Jun Duan, Max P. Prokopy, and Ronald J. Prokopy
Department of Entomology, University of Massachusetts
In recent years we have used 3-inch sticky
red spheres baited with synthetic apple odor
(butyl hexanoate) to intercept apple maggot
flies (AMF) in our pilot second-stage apple IPM
program in Massachusetts commercial or-
chards. From the results [Fruit Notes 54(1): 1-5;
55(l):4-9], we concluded that some improve-
ment in the baited sticky sphere system would
be needed for such an interception system to be
successful on a broad-scale commercial level.
One area of potential improvement lay in en-
hancing the attractiveness of baited sticky
spheres to AMF to ensure capture of a high
proportion of immigrants on perimeter trees
before they could penetrate into the orchard
interior. Previously, we reported the results of
several field tests aimed at this goal [Fruit Notes
54(4): 18-19]. We concluded that for sticky red
spheres, a size of three inches was more visually
attractive than larger or smaller sizes. We also
concluded that increasing the number of two-
dram polyethylene vials containing butyl
hexanoate beyond two vials per sphere would
not enhance AMF captures on the baited
spheres by odor attraction, and that altering the
distances between fruit-odor baited vials and a
sphere within a range of 6 to 24 inches had no
significant effect on fly captures. Besides fruit
odor, however, the odor of food (bird feces and
insect honeydew) also is attractive to AMF
[Fruit Notes 55(3):l-9]. Amajor food-type odor is
ammonia, by which AMF are guided to proteina-
ceous food. In western North America and east-
ern Canada, ammonia has been used primarily
in combination with sticky yellow rectangle
traps to monitor presence of AMF within and
near orchards. Sticky yellow rectangles are con-
sidered to be visual mimics of foliage eliciting
food-foraging behavior. They are much less ef-
fective than three-inch sticky red spheres in
commercial orchards in eastern U.S. [Fruit
Notes 41(6):6-9]. Until now, the combined value
of fruit odor and food odor in attracting AMF to
red spheres has not been investigated. Here we
describe results of recent field tests assessing
AMF response to sticky red spheres baited with
these two different kinds of odors.
Methods Used
Our tests were carried out in 1990 and 1991
at Clarkdale Fruit Farm (West Deerfield, MA),
which harbored a moderate population of AMF.
Using wire, we positioned either two 2-dram
polyethylene vials of ammonium carbonate (0.2
ounce per vial), two 2-dram vials of butyl
hexanoate (0.1 ounce per vial), one vial of each
type, or no vial (unbaited control) about 12
inches from the side of a sphere. The ammonia
was released through a 1/8-inch hole drilled in
the vial cap, while the butyl hexanoate was
absorbed by and released through the wall of the
vial. No more than one sphere was placed in each
tree. Tests were conducted from July 7 through
19, 1990 and June 23 through August 1, 1991.
Periodically, the vials of different treatment
types were rotated from tree to tree to minimize
the effects of location. At each rotation, spheres
Fruit Notes, Fall, 1991
were cleaned. Captured AMF were soaked in
paint thinner to dissolve the "sticky," and later
dissected to determine the proportion of females
that contained mature eggs.
Results
The results (Table 1) show that in each year,
more AMF were captured on spheres baited
either with one vial each of ammonia and butyl
hexanoate, two vials of ammonia, or two vials of
butyl hexanoate, than on unbaited spheres.
Captures of females in both 1990 and 1991, and
of males in 1990, were significantly greater for
1 vial each of ammonia and butyl hexanoate
than for 2 vials of ammonia or 2 vials of butyl
hexanoate, between which there was no signifi-
cant difference.
This finding surprised us. Although both
ammonia and butyl hexanoate were known to be
attractive to AMF, as we mentioned, each is
associated with a different type of response.
Ammonia emanates from proteinaceous food in
a condition favorable to fly feeding. Butyl
hexanoate is emitted by host fruit in a condition
favorable as a site for fly mating and oviposition.
Because we previously found that sources of
AMF food in nature occur almost exclusively on
foliage rather than on fruit [Fruit Notes 55(3):1-
5], we did not expect that the odor of ammonia
would attract so many AMF to red spheres. We
do not yet understand the basis of AMF attrac-
tion to ammonia-baited red spheres.
We also found that compared with the per-
centage of mature females (63 to 65%), as op-
posed to immature females, captured on spheres
baited only with butyl hexanoate or on unbaited
spheres, the percentage of mature females (48 to
55%) captured on spheres baited only with am-
monia was slightly lower. This difference likely
Table 1. Mean numbers of apple maggot females and males captured on sticky red spheres
hung in fruiting trees in a commercial apple orchard and baited with different attractive
odors over the trial periods (12 days in 1990 and 37 days in 1991).
Year
Baits*
Number
of baited
vials around
each sphere
Number
of captures
Increase in
captures on
baited spheres
relative to
non-baited
spheres (%)
Females
Males
2
te 2
16.0 c
26.8 b
27.8 b
14.7 c
26.3 b
19.7b
73
56
1990 None
Butyl hexanoate
Ammonium carbonate
Ammonium carbonate
and butyl hexanoate
1991 None
Butyl hexanoate
Ammonium carbonate
Ammonium carbonate
and butyl hexanoate
27.7 a
45.2 a
170
18.5 c
32.5 b
-
2
36.2 b
66.5 a
101
2
46.0 b
68.8 a
125
58.3 a
75.8 a
163
*Six replicates per treatment type in 1990; four replicates in 1991. Values within
year not followed by same letter are significantly different at odds of 20:1.
Fruit Notes, Fall, 1991
was because less mature females, having to feed
more often than mature ones, respond more
readily to food type stimuli. We believe that
many AMF in the test orchard originated from
fallen fruit within the orchard rather than hav-
ing immigrated into it from outside. Resident
AMF would have had more opportunity to
search for food in the vicinity of vials of ammonia
before becoming sexually mature. By chance
alone they may have alighted on an adjacent
sphere.
Conclusion
Together, our two years of results indicate
that a combination of one vial each of ammo-
nium carbonate and butyl hexanoate signifi-
cantly increases the number of alightings of
both female and male AMF on red spheres over
the effects of two vials of butyl hexanoate alone
or two vials of ammonium carbonate alone. For
future employment of sticky red spheres to in-
tercept AMF on perimeter trees as a means of
control, we suggest using combined food and
apple odors as the baits and baiting each sphere
with one vial each of butyl hexanoate and am-
monium carbonate. Further research is neces-
sary, however, to develop an optimum method of
ammonia release without undue rapid break-
down of ammonium carbonate under conditions
of high humidity.
Acknowledgement
We thank Tom Clark for use of his orchard.
This work was supported by the Northeast Re-
gional Project on Integrated Management of
Apple Pests (NE-156).
Fruit Notes, Fall, 1991
Effects of Fruit Ripening, Cultivar,
and Storage on Apple Maggot
Larval Survival
Susan L. Butkewich and Ronald J. Prokopy
Department of Entomology, University of Massachusetts
Under current practice, the times of year
when apple maggot flies (AMF) begin and cease
laying eggs in commercial apple orchards define
the period during which control measures are
used against the flies. Conceivably, however,
the larvae that hatch from AMF eggs are not
able to develop and tunnel into fruit equally well
across all fruit ripening periods or cultivars. In
fact, Reissig (1979) in western New York found
that survival of AMF larvae in apples varied
considerably with cultivar and infestation date.
For example, when apples were infested from
June 25 to July 15 and were picked September
7, the percentage of apples producing larvae was
32% in Wealthy, 12% in Mcintosh, 8% in Rhode
Island Greening, and 4% in Rome. When apples
were infested from August 16 to September 6
and again picked on September 7, the percent-
age producing larvae increased drastically to
89% in Wealthy, 59% in Mcintosh, 35% in Rhode
Island Greening, and 48% in Rome. These
findings suggest that early-season control of
AMF, especially on late ripening cultivars, may
be somewhat less important than mid- or late-
season control.
To determine how well the findings of
Reissig in western New York might apply to
Massachusetts conditions, we carried out two
experiments at the Horticultural Research Cen-
ter in Belchertown, MA Besides examining
AMF larval survival at different egg infestation
dates and for different cultivars, we also studied
larval survival under different fruit storage re-
gimes.
Methods Used
In both experiments, trees on M.7 rootstock
were covered with cloth cages beginning in late
June (before appearance of any AMF) to protect
against unwanted egglaying by wild flies.
The first experiment involved collecting eggs
laid in wax fruit by mated AMF females. Using
a small paint brush eggs were inserted into
punctures made with a sterilized needle in
Mcintosh and Delicious apples. Each apple
received five punctures and one egg per punc-
ture. Each cultivar received 100 eggs on July 22
and 200 eggs on August 20, 1987. Apples were
either picked just after artificial infestation or
were left on the trees until they fell naturally. In
both cases, fruit were kept at 72°F for six weeks,
when the percentage of eggs that gave rise to
pupae was recorded.
In the second experiment, a mature female
and mature male AMF, together with some food
and water, were placed in a cloth cage over a
cluster of Mcintosh or Delicious apples for a
period of two days to permit egglaying. The
numbers of eggs laid varied from fruit to fruit.
This procedure was carried out for 25 apples of
each cultivar each week from July 18 to August
22, 1988. Fruit were allowed to remain on the
tree until harvest: September 1 1 (Mcintosh) and
October 2 (Delicious). Then apples from each
infestation date and cultivar were divided
equally into three groups before being examined
for larval tunneling. Group one was stored at
72°F for six weeks. Group two was stored in a
cold room at 38°F for six weeks Group three was
examined immediately. Each AMF egglaying
sting was scored for larval tunnel depth by
Fruit Notes, Fall, 1991
Table 1. Percent apple
inserted into apples on
maggot survival after eggs were manually
the indicated dates (Experiment 1, 1987).
Mcintosh
infestation dates
Delicious
infestation dates
July
22
August
20
July
22
August
20
Fruit picked
just after
infestation
Fruit that
fell naturally 8
53
35
50
1
cutting successive slices under each sting until
the larval trail disappeared.
Results
The results of the first experiment (Table 1),
in which eggs were inserted into fruit manually,
were consistent with the results of Reissig's
study in New York. When fruit were left on the
tree until they fell naturally, far more pupae
were produced from Mcintosh than from Deh-
cious, a later ripening cultivar. Mcintosh in-
fested on August 20 yielded many more pupae
than Mcintosh infested on July 22. For both
cultivars after six weeks at 72°, fruit picked just
after egg infestation yielded more pupae than
fruit that were allowed to fall naturally.
The results of the second experiment (Table
2), in which eggs were inserted into fruit by the
flies themselves, again were generally similar to
Table 2. Development of apple maggot tunnels in 25 apples per cultivar per date averaged over
all treatments (Experiment 2, 1988).
Cultivar
Infestation Date
July
18
July
26
August
2
August
8
August
15
August
22
No. egglaying
stings
Average larval
tunnel score*
Mcintosh
Dehcious
Mcintosh
Dehcious
53
66
4.7
3.4
60
100
5.0
4.8
26
61
5.5
5.2
4
52
5.0
5.2
12
63
4.2
5.2
6
11
3.9
4.0
*The greater the value, the more tunneling occurred. Tunnel depth was ranked on a scale of
0-7 according to the following criteria: = puncture without tunneling; 1-6 = tunneling through
the first 0.08, 0.25, 0.5, 0.75, 1, and 1.25 inches, respectively; 7 = tunneling to the core.
8
Fruit Notes, Fall, 1991
those of the New York study. The degree of
larval t unn eling averaged over all infestation
dates and storage conditions was about the
same for Mcintosh and Delicious. For both
cultivars, average tunnel length increased
somewhat from the earliest egg infestation date
(July 18) to mid-season egg infestation dates
(August 2 and August 8). For the latest egg
infestation date (August 22), average tunnel
length was slightly less than at mid-season
dates. Interestingly, the number of oviposition
stings in Mcintosh fruit caged with flies on
August 8, 15, or 22 was quite low in comparison
with numbers of stings earlier in the season.
Likewise, in the New York study, the number of
oviposition stings per Mcintosh apple was lower
in August than in July, even though the propor-
tion of fruit yielding pupae was greater.
Data from the first experiment (Table 1)
show that more larvae survived in Mcintosh
infested on August 20 than on July 22 of 1987;
whereas, data from the second experiment
(Table 1 ) show a greater level of larval tunneling
(indicative of greater larval survival) in Mcin-
tosh infested on July 26 then on August 22 of
1988. We have no good explanation for this
apparent discrepancy, although the few num-
bers of ovipositions on the August 22 infestation
date in the second experiment may be a contrib-
uting factor.
In the second experiment, both Mcintosh
and Delicious apples examined immediately af-
ter harvest generally had less larval tunneling
than those kept in cold storage or at room
Table 3. Effect of postharvest treatment on tunneling by apple maggots (Experiment 2,
1988).
Fruit
Infestation Date
July
July
August
August
August
August
treatment
Cultivar
18
26
2
8
15
22
Tunnel development*
(number of oviposition stings)
No storage
Mcintosh
3.7
3.1
4.0
—
3.4
3.3
(26)
(19)
(20)
(0)
(5)
(3)
Delicious
3.9
4.5
4.6
4.0
4.1
4.0
(29)
(45)
(1)
(32)
(9)
(11)
Stored 6 weeks
Mcintosh
7.0
6.9
7.0
—
at 72°F
(23)
(19)
(6)
(0)
(1)
(1)
Delicious
1.6
5.0
7.0
7.0
5.8
—
(5)
(5)
(33)
(13)
(27)
(0)
Stored 6 weeks
Mcintosh
3.5
5.0
^_
5.0
5.0
4.5
at 38°F
(4)
(22)
(0)
(4)
(6)
(2)
Delicious
4.8
4.8
3.9
4.6
5.8
—
(32)
(50)
(27)
(17)
(27)
(0)
*See footnote of Table 2.
Fruit Notes, Fall, 1991
temperature (Table 3). In most cases, apples
kept in cold storage had less tunneling than
apples stored at room temperature. Cold stor-
age reduced the potential for AMF damage by
slowing larval growth and eventually killing
larvae.
Conclusions
From the combined results of the 1976 study
in New York by Reissig and this study, we
conclude that AMF larvae can cause at least
some detectable apple injury (in the form of
brown trails or tunnels) following essentially
any period when eggs are laid. For Mcintosh
and other cultivars ripening about the same
time as or later than Mcintosh, however, eggs
laid up to mid-July (in a growing season when
bloom occurs at a normal time) are less likely to
result in detectable larval injury than eggs laid
thereafter. Thus, while it may be necessary to
treat early cultivars against AMF before mid-
July, it may not always be necessary to treat
Mcintosh or later-ripening cultivars until mid-
July. In most cases, placing fruit in cold storage
immediately after harvest will slow larval devel-
opment, will reduce tunneling injury, and will
eventually kill the larvae. In cases where apples
receive AMF oviposition stings, it would be wise
to put the apples into cold storage immediately
after picking and keep them there for at least
one month.
References
Reissig, W.H. 1979. Survival of apple maggot
larvae, Rhagoletis pomonella, in picked and
unpicked apples. Canadian Entomologist
111:188-187.
Orchard Soils and Apple Rootstocks
Peter L. M. Veneman and Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
A good orchard soil is deep and well drained,
and yet retentive of moisture. In heavy soils
composed of fine particles, the spaces between
the particles are so small that water does not
drain out of the soil quickly following heavy
rains. Thus oxygen, which is necessary for root
development and growth, is excluded from
heavy, wet soils. Tree growth and fruit produc-
tion are very poor on such soils. Furthermore, in
soils which are composed of coarse particles,
water drains too quickly following rains. Trees
are therefore deprived of water, and under those
conditions tree growth and fruit production are
also poor. Both of these situations may be
modified by the grower. Poorly-drained soils
may be artificially drained to help alleviate
some of the problems, and likewise, excessively-
drained soils can be irrigated to provide ad-
equate moisture to trees. Unfortunately, these
solutions are expensive. In many situations
alternative sites may be chosen, or alternative
rootstocks may be used which provide better
performance under adverse conditions. In this
article information provided in a previous Fruit
Notes article [1985, 50(3):l-4] is updated to
include a larger number of soils representative
of the entire New England region, and further
information on rootstock compatibility with
various soil types is provided.
Size-controlling rootstocks are usually more
demanding than seedling rootstocks in respect
to drainage, depth of soil, and water-holding
capacity; therefore, when deciding on which
rootstock to use, it is very important to know the
10
Fruit Notes, Fall, 1991
soil types of the land to be planted. The proper
match between rootstock and soil may make the
difference between the success or failure of the
planting.
Careful observation of the natural vegeta-
tion growing on or adjacent to the site selected
for the orchard can be helpful in determining the
suitability of the soil for fruit trees. Pitch pine
Table 1. Grouping of New England soils according to suitability for apple orchards.
Group I. Gravelly or sandy soils with a tendency to drought.
Adams
Canaan
Carver
Colton
Dukes
Enfield
Evesboro
Groton
Herman
Hinckley
Jaffrey
Merrimack
Plymouth
Quonset
Shapleigh
Stetson
Suncook
Windsor
Group n. Gravelly or sandy soils, without the tendency to drought.
Agawam
Canton
Copake
Essex
Galestown
Gloucester
Groveton
Haven
Hinesbury
Katama
Lincroft
Montauk z
Oakville
Poquonock 2
Warwick
Group III. Good, deep soils with average to good drainage and a good
waterholding capacity.
Berkshire
Cheshire
Hadley
Ondawa
Riverhead
Brookfield
Chilmark
Hartland
Pittsfield
Unadilla
Charlton
Colrain
Lenox
Pollux
Yalesville
Chatfield
Dutchess
Narragansett
Group IV. Good but somewhat shallow soils with hardpan or bedrock that
prevents deep rooting.
Bernards ton
Holyoke
Melrose
Newport
Stockbridge
Brimfield
Lyman
Minis
Pax ton
Suffield
Broadbrook
Marlow
Nantucket
Shelburne
Wethersfield
Hollis
Meckesville
Nassau
Group V. Soils that tend to be wet for a short period of time, but usually not during
the growing season.
Acton
Amenia
Amostown
Becket*
Belgrade
Birchwood*
Buckland z
Buxton
Deerfield
Eldridge
Elmwood
Hero
Klej
Ludlow 1
Matawan
Ninigrit
Peru z
Pitts town 1
Podunk
Rainbow z
Scio
Scituate 1
Sudbury
Sutton
Tisbury
Wauchaug
Wincoski
Woodbridge
/
z Denotes presence of a hardpan.
Fruit Notes, Fall, 1991
11
Table 1. Continued.
Group VI.
Poorly drained soils, unsuitable for tree fruits unless artificially
drained.
Adrian
Enosburg
Mansfield 1
Raynham
Swansea
Au Gres
Fredon
Maybid
Ridgebury*
Swan ton
Berryland
Freetown
Menlo z
Rumney
Walpole
Biddeford
Halsey
Munson
Saco
Wareham
Birdsall
Ipswich
Norwell 1
Saugatuck
Waumbek
Brockton*
Kendaia
Palms
Scantic
Westbrook
Cabot 1
Leicester
Pawcatuck
Scitico
Whately
Carlisle
Limerick
Peacham 1
Scarboro
Whitman 1
Croghan
Lyons
Pipestone
Skerry 1
Wilbraham 7
Duane
Madawaska
Pompton
Stissing*
l Denotes presence of a hardpan.
'
M.9 or M.9 EMLA
M -26 or M.26 EMLA
Mark
M.9/MM.1M
M.9/MM.111
M.7, M.7A, or M.7 EMLA
MM.106
MM. Ill
Seedling
V/////////////A
y/////////////A
^%^^%^
V/////////////////A
<^^#^^%
Y/////////////////////A
^^%m<%i
*#^^^^^^^
y/////////^^^^^
i i i i
]
Figure 1. An approxii
12 3 4 5 1
Soil Suitability Group
nate guide of rootstock-soil compatibility.
12
Fruit Notes, Fall, 1991
and scrub oak indicate gravelly soil which is
excessively drained and subject to drought. Red
maple, alder, and willow indicate a soil which is
poorly drained and excessively wet. Sugar
maple and white ash do best on deep, fertile,
well-drained soils of good water-holding capaci-
ties.
The first step in matching roots tocks and soil
is to determine the soil types for the land to be
planted. Soil survey reports are available from
the U.S. Department of Agriculture-Soil Con-
servation Service. If no soil map is available for
the area in question, an on-site inspection by a
qualified soil scientist or extension fruit special-
ist will provide the necessary information.
New England soils can be grouped into six
categories (Table 1). Keep in mind that these
suitability groupings are based on internal soil
characteristics. External properties, such as
landscape position and drainage potential, are
not considered; therefore, Sites with soils listed
as favorable in Table 2 may not be suitable for
apple production because of their location.
Once you have analyzed the soil, refer to the
tentative guide for rootstock/soil compatibility
in Figure 1 to determine which rootstocks are
most suitable for your soil conditions. This
figure combines older observations as presented
in the earlier Fruit Notes article with informa-
tion presented on rootstock interaction with
soils in the last issue of Fruit Notes [56(3):9-13]
and field observations on performance. These
suggested compatibilities are tentative and will
change as more information becomes available.
Fruit Notes, Fall, 1991
13
The 1991 Apple Harvest Season in
Massachusetts
Wesley R. Autio
Department of Plant & Soil Sciences
Since 1986, we have been conducting regu- rity. We started assessing Mcintosh ripening in
lar starch-iodine evaluations at orchards 1986 and subsequently added Empire, Deli-
throughout Massachusetts to follow fruit matu- cious, and Cortland to the cultivars being tested.
Starch index value
8
6
Not for long-term storage
Suitable for CA storage
Immature
i i i i I i i i i I i i i i I i i i i I i i i i I i i i i I i i i i I i i i i I i i i i I i i i i I i i i i
-20 -15 -10 -5 5 10 15 20 25 30 35
Days after August 31
Figure 1. Starch-iodine values of Mcintosh fruit during the harvest seasons from 1986
through 1991.
14
Fruit Notes, Fall, 1991
Starch index value
7
5
3
■ ^*r
8 13 18 23 28 33
Days after August 31
Figure 2. Starch-iodine values of Cortland fruit during the 1990 and 1991 harvest seasons.
In this article, I will give a brief description of the
1991 harvest season for each of these cultivars.
Mcintosh
Bloom in 1991 was approximately 10 to 14
days ahead of normal. Throughout the summer
many predictions were made as to the approxi-
mate date of apple harvest; however, the basic
answer was, "Who knows!" The third week of
August brought Hurricane Bob, which further
confounded the issue. The hurricane resulted in
a significant amount of drop in some areas and
enough damaged fruit to result in further drop
in the last week of August. This drop made
many growers very concerned, and a large
amount of spot picking was done during the last
week of August and the first week of September.
Ripening of the majority of fruit, however, was
not dramatically early. Figure 1 shows the
starch-iodine values for this season compared
with the previous five seasons, and average
values suggested that harvest should have be-
gun on approximately September 7, only five
days ahead of normal. Once harvest began in
earnest, the weather cooled off and by the
middle of the season Mcintosh were only two to
three days ahead of normal.
Interestingly, even though the bloom was
very early (much earlier than it has been in
recent years), the ripening of Mcintosh in 1991
was later than in 1986 and similar to that in
1987.
Fruit Notes, Fall, 1991
15
9
6
3
i
c
Figure 3.
through 1!
Starch index value
* *
' i I'
f *■ * ■
i i i i 1 i i i i I i i i i I i i i i I i i i i I i i i i I i i i i
) 14 19 24 29 34 39 44
Days after August 31
Starch-iodine values of Empire fruit during the harvest seasons from 1988
J91.
Cortland
This year was only the second that we have
followed the starch-iodine levels in Cortland
fruit; however, there were significant differ-
ences between 1990 and 1991. Figure 2 shows
the changes in starch-iodine values in 1990 and
1991. Fruit in the middle of the harvest season
in 1991 were approximately five days ahead of
those in 1990. I am not sure if 1990 was a normal
season, but these data are consistent with those
for Mcintosh and Empire.
Empire
Figure 3 shows the starch-iodine values for
Empire fruit during the harvest seasons from
1988 through 1991. As with Cortland the aver-
age fruit at mid-season in 1991 were approxi-
mately five days ahead of those in the previous
three seasons.
Delicious
Figure 4 shows the starch-iodine values for
16
Fruit Notes, Fall, 1991
Starch index value
6
5
4
3
2
-
m^s^
^s^
-
■
^-"
-
j0>
■
**
f
f
_ ^
1
^ **
**
**
--'&
\y^^ ■ ,'""
**
^ f*
«f
- .... 1 .... 1 . . i ■ 1 . I I 1 1 J 1 .J — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1 — 1
13 18 23 28 33 38 43 48
Days after August 31
Figure 4. Starch-iodine values of Delicious fruit during the 1988, 1989, and 1991 harvest
seasons.
Delicious fruit during the 1988, 1989, and 1991
harvest seasons. Results from Delicious were
not consistent with those for the other three
cultivars. If the average of 1988 and 1989
represents a normal season, i.e. the middle of the
harvest season on approximately October 8,
then 1991 was about 13 days ahead of normal.
This difference was very obvious in terms of the
very early development of watercore, as well as
significant preharvest drop. It is unclear why
Delicious were as early as they were, but it may
have been related somewhat to Hurricane Bob.
Delicious have a very long pedicel and may have
received more damage as a result of being blown
around. This damage may have caused signifi-
cant numbers of fruit to ripen earlier than nor-
mal. Clearly, they experienced more drop as a
direct result of the hurricane.
The 1991 season was one that most growers
would prefer to forget. The cold damage in April,
the early bloom, the poor set, Hurricane Bob, an
un-nerving harvest season, and (as always) the
uncertainty of the market together made all of
us wish that it was 1992.
Fruit Notes, Fall, 1991
17
Toxicity of Fungicides to Apple Pollen
Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Following a heavy bloom, it is particularly
frustrating to see poor fruit set; yet, many Mas-
sachusetts orchards have seen this problem for
the past few years. There are a number of
potential reasons for poor set. Cold stress, oil
toxicity, dry weather during flower set, nutri-
tional deficiency, insecticide damage, and fungi-
cide damage all have been implicated. As yet,
nothing has stood out as the prime culprit.
In looking for a reason for these years of poor
fruit set, some work done in England came to
light. Over several years, researchers (chiefly
Ruth Church at Long Ashton Research Station)
examined the effects of different fungicides on
apple pollen survival. Obviously, if pollen viabil-
ity (or its ability to fertilize eggs) decreases,
there will be fewer fruit set, regardless of bloom,
bee activity, or pollination weather.
To make a long story short, it appears that
captan can drastically decrease pollen viability.
The effect can be seen in both laboratory and in
field tests. The results presented in Table 1 do
not state what the specific effect on fruit set is;
however, captan was the only material that
severely reduced pollen germination in labora-
tory and orchard studies.
In another study, dilute applications of cap-
tan were more toxic than concentrated applica-
tions (about 5X). Time of application also was
important. The closer to pollination that an
application was made, the more chance there
was that pollination was inhibited. Church
showed that applications made within 24 hours
of pollination were very detrimental to fruit set.
In one test, hand pollinated blossoms were
sprayed with different fungicides either before
or after pollination. The results (Table 2) indi-
cate that if pollination occurred two hours before
spraying, pollen did not grow adequately, but if
the pollination occurred two hours after spray-
ing, pollen tubes developed relatively well.
More recently, laboratory tests have com-
pared sterol-inhibiting (SI) fungicides and cap-
tan. Again, captan was highly toxic to pollen.
Dodine was also somewhat toxic in several tests.
As Table 3 shows, the SI fungicides did not have
Table 1. Toxicity of fungicides to pollen in the orchard and laboratory (after Church et
al., 1983).
Orchard test
Laboratory test
Approximate
Germinated
LD50 (amount
concentration
pollen grains
needed to kill
Germination
Treatment
(per 100 gal)
per stigma
50% of pollen)
(% of control)
Unsprayed
_
1.9
—
—
Benomyl
30 oz
1.5
18.1
95
Captan
7 lbs
0.5
0.7
6
Dodine
16 oz
0.3
15.7
100
Mancozeb
7 lbs
plus Ziram
7 lbs
1.5
16.3
100
Sulfur
15 lbs
0.1
16.5
75
18
Fruit Notes, Fall, 1991
Table 2. Percent of hand-pollinated stigmas showing adequate pollen tube
when sprayed with fungicides (after Church and Williams, 1977).
development
Treatment
Time of pollination relative to spraying
1 day before
2 hrs before
2 hrs after
1 day after
2 days after
Control
Benomyl
Captan
Karathane
Thiophanate-m
84
76
88
84
84
79
67
25
20
80
79
84
70
85
89
92
96
84
64
84
88
100
84
60
92
Table 3. Germination
of pollen in
laboratory tests (after
Watters and Sturgeon,
1990).
Germination (%)
Treatment
Treated
Control
to control (%)
Mancozeb
19.1
17.2
111
Nova (SI)
11.0
10.6
104
Hexaconazole (SI)
23.8
23.6
101
Topsin-M
15.9
17.2
92
Dodine
11.4
13.9
79
Captan
3.5
13.9
17
a dramatic effect on pollen germination.
In summary, the application of captan dur-
ing bloom may create problems with pollen
germination, and therefore inhibit pollination.
Dodine also may be a problem, but appears to be
less toxic than captan. These results may ex-
plain why some orchards have had problems
with fruit set in recent years, when captan and
dodine have been used much more heavily than
in years when the EBDC fungicides were avail-
able, especially around bloom. The Sis and
Benlate or Topsin-M appear to be less toxic to
pollen. The safest route to take may be to avoid
applying any fungicide during good pollination
weather. If a fungicide must be used, then one
of the less toxic fungicides should be applied.
Finally, this area needs to be studied further,
more carefully relating fungicide application
and fruit set. While the results from England
are highly suggestive, they are not well repli-
cated or conclusive.
References
Church, R. M., B. K Cooke, and R. R. Williams.
1983. Testing the toxicity of fungicides to
apple pollen. J. Hort. Sci. 58:161-163.
Church, R. M., and R. R. Williams. 1977. The
toxicity to apple pollen of several fungicides as
demonstrated by in vivo and in vitro tech-
niques. J. Hort. Sci. 52:429-436.
Watters, B. S. and S. R. Sturgeon. 1990. The
toxicity of some foliar nutrients and fungicides
to apple pollen cv. Golden Delicious. Tests of
agrochemicals and cultivars 11. Ann. Applied
Biol. 116(supplement):70-71.
Fruit Notes, Fall, 1991
19
Fruit Notes
University of Massachusetts
Department of Plant & Soil Sciences
205 Bowditch Hall
Amherst, MA 01003
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Fruit Notes
!
ISSN 0427-6906
... i
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension System,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
■
LOGICAU
;
Volume 57, Number 1
WINTER ISSUE, 1992
Table of Contents
Biological Control of Botrytts
Grey Mold In Strawberry
Strawberry Cultlvars Differ In Susceptibility
to Tarnished Plant Bug Injury
Observations from the 1991 Massachusetts
Apple Integrated Pest Management Program
Notching Increases Branching on Apple Trees
Second-level Apple Integrated Pest Management:
The Effects of Summer Pruning and a Single Fungicide
Application on Flyspeck and Sooty Blotch
Fruit Notes
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Fruit Notes
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University of Massachusetts
Amherst, MA 01003
COOPERATIVE EXTENSION SYSTEM POLICY:
All chemical uses suggested in this publication are contingent upon continued registration. These chem icals 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 arc used for identification, no company endorsement or product d i scrim ination
is intended. The University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied,
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DAMAGE.
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furtherance of the acts of May 8 and June 30, 1914. The University of Massachusetts Cooperative Extension System
offers equal opportunity in programs and employment.
Biological Control of Botrytis
Grey Mold in Strawberry
John C. Sutton
Department of Environmental Biology, University of Guelph, Ontario
The fungus Botrytis cinerea, commonly
known simply as Botrytis, is probably the most
destructive pathogen of strawberry worldwide.
Botrytis is the chief cause of fruit rot in strawber-
ries, but it also is able to infect leaves and
flowers. The disease it causes is referred to
widely as gray mold after the sporulation struc-
tures the fungus produces on affected tissues.
Fruit rot symptoms may appear in berries as
they ripen in the field or after they have been
picked. For more than a half century, the chief
means of controlling fruit rot has been fungicide
applications when the crop is flowering and
fruiting. Finding fungicides which effectively
control gray mold is becoming increasingly diffi-
cult, and in the absence of satisfactory alterna-
tive measures, the vulnerability of strawberry
crops to Botrytis is increasing.
The heavy dependency of fruit rot manage-
ment on fungicides is threatened by public per-
ceptions and concerns regarding fungicide resi-
dues in the foliage and fruits at picking time, and
by declining availability of effective fungicides.
Many consumers now reject berries from treated
crops regardless of care taken by the grower in
using fungicides or the presence of any residues.
Botrytis has an extraordinary record of develop-
ing resistance to fungicides such that on some
farms only one or two registered fungicides
remain effective. New fungicides are not being
registered. The demise of fungicide programs
prompted us to explore alternative approaches
to fruit rot management, in particular, biologi-
cal control of Botrytis through the use of various
microfungi and bacteria.
The general concept of biological control of
plant diseases is straightforward, but few suc-
cessful systems of biocontrol have been devel-
oped since pioneering efforts in the 1930's. In
essence, biological control involves the applica-
tion to the crop of microorganisms that do not
harm the crop but suppress disease-causing
organisms and thereby control disease. Reports
that organisms successfully suppressed disease
under controlled conditions but failed to do so in
the field seem endless. We can be certain from
many studies, however, that biocontrol of micro-
organisms, including pathogenic fungi and bac-
teria, happens all the time in the microbial "dog-
eat-dog" worlds of crops, plant residues, and soil.
At certain times, biological and other natural
li mits on populations of pathogens simply are
insufficient to prevent disease outbreaks. In the
case of strawberry fruit rot, we considered that
it may be possible to augment natural forces
that suppress disease, provided that we could
find the right kinds of control organisms and
learn how and when to use them. We were under
no illusions that shotgun techniques or a super-
ficial approach would provide the desired re-
sults. Our research program was, as a conse-
quence, comprehensive and required detailed
information on gray mold, the strawberry micro-
flora, and complex interactions of pathogen,
control organisms, strawberry plant, and micro-
climate.
A search for organisms that suppress Botrytis
effectively under a wide range of weather and
crop conditions was started in 1986. We chose to
look for possible biocontrol organisms in straw-
berry plant materials collected in growers' fields
and in research field plots. The rationale was
that organisms with strong adaptation to straw-
berry as well as suppressive activity toward
Botrytis would be more likely to function well as
biocontrol agents in the field than would organ-
isms from other sources such as soil or culture
collections. No fields with suspected high levels
Fruit Notes, Winter, 1992
of biocontrol were known; however, evidence of
natural biocontrol of Botrytis was found in straw-
berry leaves from various fields by then gradu-
ate student P. Gordon Braun. Another student,
Morven McLean, proceeded to monitor the straw-
berry microflora year round, including periods of
snow cover. She quantified mycelial fungi, yeasts ,
and bacteria on living and dead foliage, flowers,
and fruits. This overview of the microflora
provided an important background to biocontrol
studies. A collection of organisms initiated by
Ms. McLean was expanded greatly by graduate
student Peng Gang, who subsequently evalu-
ated the isolates as biocontrol candidates against
Botrytis.
The evaluation of several hundred microor-
ganisms as biocontrol candidates required pro-
cedures that were efficient but realistic. Tests in
field plots provide low "representational error."
Representational error is the error that may
arise from differences between conditions in the
tests and in growers' fields. For logistical rea-
sons all isolates could not be tested in field plots,
which must be suitably replicated and adequately
spaced to minimize interplot interference such
as that arising from the spread of biocontrol
organisms among plots. Conditions in labora-
tory tests may differ enormously from those in
the field but when suitably designed may allow
for rapid evaluation in an initial screening.
Tests that utilize plant materials are likely to be
more realistic (less representational error) than
those done on artificial substrates such as agar
media. Tests on plants in the growth room and
greenhouse may provide conditions intermedi-
ate between the laboratory and the field.
Peng Gang conducted comparative biocontrol
tests on leaf discs and detached petals in the
laboratory, on attached leaves and flowers in the
growth room and greenhouse, and on plants in
the field. Biocontrol effectiveness of 230 isolates
on leaf discs ranged from to 100%. These
isolates were grouped into five categories repre-
senting different ranges of biocontrol effective-
ness. Representatives of each group then were
tested in the growth room, greenhouse, and
field. In most instances, relative effectiveness of
the isolates in various controlled conditions was
similar to that in the field. The controlled tests
thus provided a strong indication of biocontrol
activity of organisms in the field. The more
effective organisms were fungi known as
Gliocladium roseum, Penicillium sp.,
Trichoderma viride, Epicoccum purpurascens,
and Trichothecium roseum. Yeasts and bacteria
often did not perform well in the field.
Field studies conducted during four crop
seasons at various locations in Ontario demon-
strated that several microfungi controlled
Botrytis on strawberry flowers and fruits as
effectively as captan, a fungicide that is recom-
mended widely for fruit rot control. In a majority
of tests, spores of the fungi were suspended in
water (one million spores/ml) and applied with a
hand-operated sprayer. The biocontrol fungi
were applied at five- to seven-day intervals from
the green flower-bud stage to the white-pink
fruit stage. Botrytis was applied once to improve
test conditions. Fruit rot was assessed after the
berries had been stored for seven to ten days
under conditions highly favorable for Botrytis.
The biocontrol agents generally suppressed rot
by about 65 to 85%. The fungi Gliocladium,
Trichoderma, and Penicillium each suppressed
Botrytis effectively, but overall, Gliocladium
was the best.
Biocontrol agents or fungicides applied dur-
ing flowering and fruiting suppress fruit rot
largely by protecting the flowers against infec-
tion by Botrytis . In almost all instances , Botrytis
infects the flowers from which it grows into the
developing fruits, giving rise to the familiar rot
at the stem end of the fruit. Direct infection of
fruit usually occurs only when infected petals or
diseased berries adhere to the fruit surface.
Protection of the flowers is the most commonly
used strategy for fruit rot control; however, an
alternative is to destroy Botrytis at the source.
In Ontario, and possibly in other areas of
northeastern North America, almost all Botrytis
spores produced when strawberries are flower-
ing are formed on dead leaves infested with
mycelia of the pathogen. The leaves are infected
chiefly when they expand, but Botrytis remains
dormant in the outer portion of the leaf until the
leaf turns yellow and dies. The fungus then
grows rapidly within the leaf and is able to
sporulate in a couple of days. The spores are
Fruit Notes, Winter, 1992
dispersed to flowers by wind or splashing rain.
Most fungicides are not particularly effective in
reducing spore production on the leaves; how-
ever, we found that chlorothalonil (Bravo™)
applied to green and dead leaves before flower-
ing suppressed fruit rot as effectively as captan
applied in the conventional way during flower-
ing and fruiting. Could we achieve the same
kind of result with biocontrol fungi?
We found that the Gliocladium, Trichoderma,
and Penicillium fungi each suppressed Botrytis
in the leaves markedly and sometimes com-
pletely. The tests were done in the field in the
spring, late summer, and fall. Again, Gliocladium
was overall the most effective fungus, in part
because it was highly suppressive under cool ( 50
to 59°F) as well as warm (68 to 77°F) conditions.
Effectiveness of the other fungi was reduced
below 59°F. Gliocladium roseum is now being
developed further as a biocontrol agent.
Spray applications of biocontrol agents to
protect flowers and fruits are horrendously waste-
ful. Only a tiny fraction of the spray is deposited
on the intended target, the flowers. Moreover,
flowers that open after spraying likely remain
unprotected until the next spray is applied,
during which time Botrytis may attack the flow-
ers. Is there a more efficient method? Why not
use honey bees?
Our studies have shown that honey bees are
effective vehicles for delivering spores of
Gliocladium to strawberry flowers. With the
help of Dr. Peter Kevan, a pollination biologist
at the University of Guelph, a special spore
dispenser was designed to fit inside bee hives.
Spores of Gliocladium were blended with talc
(500 million spores per g) and the formulation
was placed in the dispenser, which, in turn, was
inserted into the hive. As bees left the hive,
spores and talc adhered especially to the hairs
on their legs and bodies. Payloads on take-off
were around 200,000 to 400,000 spores per bee.
Many missions of the "bee-52s" each day main-
tained about 50,000 spores on each flower, which
suppressed fruit rot as effectively as spray appli-
cations. A bit of blanket bombing of leaves by
overflying bees also was evident. Formulation
was replaced in the dispensers every second or
third evening after the bees settled in for the
night.
From our studies we conclude that biological
control is a feasible alternative to fungicides for
managing Botrytis in strawberries, at least in
Ontario. Gliocladium roseum is the most effec-
tive biocontrol agent we have been able to find,
and isolates of this fungus are consistently as
effective or better than captan; however, some of
the other fungi examined also may have a place
in a biocontrol program. Several strategies are
open to us for using Gliocladium. We could
apply it to leaves to suppress Botrytis at the
source, or to the flowers to protect them against
spores of the fungus, or we could use both ap-
proaches. In all instances we simply would be
increasing the amount of a fungus that occurs
naturally and frequently, but harmlessly on
strawberries in commercial fields. It would not
be difficult to develop honey bees as a low input
approach to applying fungi to the flowers, but
this may require use of bee attractants on the
strawberries in some instances. Technical
aspects of developing Gliocladium roseum for
large scale use appear entirely feasible. Satisfy-
ing the requirements for registration agencies
are forthcoming hurdles that are not entirely
clear at this time.
This article was reprinted with permission from Northeast LISA Small Fruits Newsletter 2(2):1 -3.
For information about Northeast LISA Small Fruits Newsletter, contact David Marchant, Depart-
ment of Plant Pathology, Fernald Hall, University of Massachusetts, Amherst, MA 01003 (tele-
phone: 413-545-0179).
»A» vL» «X> %L» »JL*
«Y» *X* *T* "T* "T*
Fruit Notes, Winter, 1992
Strawberry Cultivars Differ in
Susceptibility to Tarnished
Plant Bug Injury
David T. Handley
University of Maine Cooperative Extension,
Highmoor Farm, Monmouth, ME
Strawberries resistant to tarnished plant
bug? Although it may sound too good to be true,
research at the University of Maine suggests
that some strawberry cultivars may be consid-
erably less susceptible to tarnished plant bug
injury than others. Twenty strawberry culti-
vars, all currently available from commercial
nurseries, were grown in small, replicated plots
which received reduced insecticide applications
for two seasons. While some cultivars had more
than half of their crop ruined by tarnished plant
bug (seedy ends or "buttoning"), others showed
very little damage and high marketable yields.
Tables 1 and 2 show the amount of tarnished
Table 1. Tarnished plant bug injury (percent of fruit by
number) and
marketable yields of 20 strawberry cultivars in
Monmouth,
ME, 1987.'
Tarnished plant
Marketable
Cultivar
bug injury(%)
fruit (g)
Honeoye
22.3
a
3314
a
Annapolis
26.6
ab
1150
efgh
Glooscap
27.3
ab
2830
ab
Veestar
31.0
abed
798
gh
Sparkle
25.7
ab
2926
ab
Canoga
29.9
abc
2405
be
Raritan
38.1
bede
1572
defg
Earliglow
44.5
cdefg
934
efgh
Redcoat
39.9
bedef
1669
de
Guardian
46.2
defg
1352
efgh
Allstar
47.2
efg
1031
efgh
Cornwallis
47.8
efg
1060
efgh
Blomidon
48.1
efg
934
efgh
Redchief
53.5
efg
1353
efgh
Scott
49.6
efg
996
efgh
Catskill
45.6
defg
1593
def
Kent
44.4
cdefg
2091
cd
Mic mac
54.9
fg
1069
efgh
Surecrop
57.2
g
707
h
Midway
55.5
fg
830
fgh
'Means not followed by the same letter within
columns are significantly
different at odds of 19:1.
Fruit Notes, Winter, 1992
Table 2. Tarnished plant bug injury (percent of fruit by number) and
marketable yields of 20 strawberry cultivars in Monmouth, ME, 1988.*
Tarnished plant Marketable
Cultivar
bug injury(%) fruit (g)
Honeoye
27.2
a 4084
a
Sparkle
27.1
a 2674
be
Canoga
33.6
ab 2290
bed
Redcoat
26.9
a 3224
ab
Catskill
30.4
a 3071
ab
Veestar
30.4
a 1377
de
Annapolis
39.3
abed 1750
cde
Surecrop
38.4
abed 1621
cde
Midway
34.5
abc 859
cde
Guardian
38.0
abed 1400
de
Allstar
39.0
abed 887
e
Glooscap
45.6
bede 1866
cde
Scott
45.9
bede 1539
cde
Redchief
49.0
cde 1857
cde
Blomidon
47.8
bede 1141
de
Earliglow
47.7
bede 1318
de
Raritan
52.1
de 1085
e
Cornwallis
57.4
e 1132
de
Mic Mac
55.8
e 1071
e
Kent
52.3
de 3195
ab
'Means not followed by the same letter within columns are significantly
different at odds of 19:1.
plant bug injury observed in each of the twenty
cultivars, expressed as the percent injured,
unmarketable fruit. Significant and relatively
consistent differences were observed over the
two years of the study. Honeoye had the lowest
amount of injury during both years. Sparkle,
Veestar, Annapolis, and Canoga also had low
amounts of injury. Kent, Mic Mac, Scott,
Blomidon, and Redchief had the highest levels of
injury, while Guardian and Allstar consistently
fell into the middle range. The other cultivars
did not show a consistent trend over the two
seasons.
Cultivars which were less susceptible to tar-
nished plant bug, such as Honeoye and Sparkle,
also had the highest marketable yields when
compared to susceptible cultivars such as Mic
Mac and Blomidon. Kent was an exception to
this rule, however, having both high amounts of
injury and high marketable yields. This result
probably is related to the exceptionally large
number of fruit this cultivar produced.
There was no apparent relationship be-
tween the amount of tarnished plant bug injury
and the time of ripening for the different culti-
vars. Resistant and susceptible types occurred
among both early and late ripening cultivars;
however, damage appeared to be more preva-
lent on the later ripening fruit within each
cultivar, i.e. tertiary and quaternary fruit on
each plant seemed to have more injury.
There may be some genetic relationship as-
sociated with the apparent resistance found in
this study. Honeoye and Canoga, which were
resistant to tarnished plant bug, both have
Holiday as a parent, which in a non-replicated
trial had the lowest injury of any cultivar stud-
ied. Sparkle also showed resistance in this
Fruit Notes, Winter, 1992
study, as did its daughter Veestar. A relation-
ship was also apparent with the susceptible
cultivars. Kent and Mic Mac for example, were
highly susceptible to tarnished plant bug, and
both have Tioga as a parent.
Based on the results of this study, should we
all plant Honeoye and Sparkle and reduce insec-
ticide sprays for tarnished plant bug? No. Well,
not yet anyway. Although the results are prom-
ising, it is not known if similar results could be
expected in large blocks of single cultivars which
are typical of commercial plantings. Further-
more, it is important to remember that factors
other than tarnished plant bug must be taken
into account when selecting cultivars. Honeoye
for example, is highly susceptible to red stele
root rot, and Sparkle chronically has had prob-
lems with poor fruit size and firmness.
Further testing of tarnished plant bug resis-
tance is underway, funded by the USDA Low
Input and Sustainable Agriculture Project,
which may provide more insight into its poten-
tial for strawberries. Resistance to tarnished
plant bug is being used in other crop plants , such
as cotton and alfalfa. The differences observed
among strawberries in this study suggest that
resistance occurs in this crop as well, and with
careful breeding and selection, may offer an
important means of reducing tarnished plant
bug injury.
This article was reprinted with permission from Northeast LISA Small Fruits Newsletter 2(2) A-5.
For information about Northeast LISA Small Fruits Newsletter, contact David Marchant, Depart-
ment of Plant Pathology, Fernald Hall, University of Massachusetts, Amherst, MA 01003 (tele-
phone: 413-545-0179).
*vj> vL» vL» *A*
#T» *t* *T^ *T*
Observations from the 1991
Massachusetts Apple Integrated
Pest Management Program
Kathleen P. Leahy
Department of Entomology, University of Massachusetts
The Apple Integrated Pest Management
(IPM) Program in Massachusetts participated
in the Second-level Apple IPM Project. During
the season 24 orchard blocks were scouted rang-
ing in size from four to ten acres each. Six of
these blocks were in a transitional phase be-
tween standard IPM and second-level IPM, six
of the blocks were managed under full second-
level IPM, and the remaining twelve blocks were
managed using standard IPM practices. In
these blocks, the primary cultivar was Mcin-
tosh; however, significant numbers of Cortland
and Delicious trees were included. Small num-
bers of Golden Delicious, Paulared, Empire,
Mutsu, Early Mcintosh, and Spartan trees were
also present.
Mites
Owing to a high rate of survival from the
very mild winter in 1990-91, mites were the
most problematic pest in Massachusetts this
Fruit Notes, Winter, 1992
year. In most years, if growers apply oil, espe-
cially two applications, mites do not begin to
increase until late June or early July. This year,
however, they were evident in many orchards at
petal fall. Some orchards which had problems
with their oil sprays had 30 mites per leaf on
some leaves at petal fall, and those trees were
showing bronzing by the end of May. Most
growers were able to control these early out-
breaks with miticide or summer oil. Low-spray
blocks had noticeably fewer problems with
mites, although we had to allow four of the six
growers to apply low rates of miticide in our "no-
spray" blocks to prevent excessive mite injury.
In these cases, however, a single half-rate treat-
ment or a spot treatment, was usually sufficient.
Flyspeck
There was a significant increase in flyspeck
incidence during the third week in September,
presumably because of the wet weather in Au-
gust. Fortunately, Mcintosh harvest was
nearly finished by the time flyspeck became
assessed)
*. 4
1
O
° T
cj 3
o
K 2
-
Injury
1
1 1 , .
AMF CM LR PC TPB EAS LH SJS
Figure 1: Insect injury to fruit in EPM
and check blocks, 1991. AMF = apple
maggot fly, CM = codling moth, LR =
leafrollers, PC = plum curculio, TPB =
tarnished plant bug, EAS = European
apple sawfly, LH = leafhopper (frass),
SJS = San Jose scale.
evident in the field. Some growers maintained
a conservative fungicide program early in the
summer and stopped spraying in mid- to late-
August, with varying success. Growers face a
dilemma when conditions for infection occur late
in the season: use a fungicide and risk the
presence of some residue at harvest, or withhold
the fungicide and risk some injury at harvest.
Leafminers
Where populations were high last year, sur-
vival of leafminers through the winter was
nearly 100%. This situation presented some
control problems in the early season. In one
orchard where leafminers were not controlled
and populations were high, it became impossible
to distinguish generations as the summer wore
on. Some low-spray blocks had high levels of
parasitism.
Tarnished Plant Bug
As has been the case for the past three
seasons, tarnished plant bugs were below treat-
ment threshold levels in most of our monitored
blocks. Total injury in our harvest survey of over
10,000 fruit was 5%, but the majority of this
injury did not cause downgrading.
Plum Curculio
Curculio pressure was very high in the
weeks following petal fall, but most growers
were alert to the situation and maintained in-
secticide coverage. Injury at harvest was not
severe in our monitored blocks.
European Apple Sawfly
Populations of sawfly returned to near nor-
mal from the very low levels seen in 1990. As
with curculio, however, growers were able to
control sawfly with a prompt petal-fall insecti-
cide.
White Apple Leafhopper
This insect was not a problem statewide, but
we had population explosions in two of our test
blocks. Neither block was treated for first-
Fruit Notes, Winter, 1992
fruit assessed)
-
O
7
_
O
O
K 2
U
3
£ 1
*3
1 1 , ,
Scab FS SB CER BR BP Rust Spray
Figure 2: Disease and physiological
injury to fruit in IPM and check blocks,
1991. FS = flyspeck, SB = sooty blotch,
CER = calyx end rot, BR = black rot, BP
= bitter pit.
generation nymphs. The first, which had been
well under the threshold this year although
leafhoppers had been a problem last year, had
an explosion in the second generation which the
grower was able to control with Thiodan™. The
second, which was marginally under the thresh-
old, showed very little activity during the second
generation, and did not appear to be a problem
early in the third generation, but suddenly ex-
ploded in mid-September. It appears that an-
other, very similar, species of leafhopper, the
rose leafhopper, may move into apple orchards
shortly after the first generation of white apple
leafhopper; this immigration may explain the
unusual outbreak patterns that we saw.
Scab
Fruit scab was noted in a number of blocks
that had used a sterol-inhibiting fungicide pro-
gram through primary scab season. Levels were
not excessively high, averaging 0.5% in our
harvest surveys, but it was a severe reminder of
the unforgiving nature of these materials.
Apple Maggot Fly
There was immigration of apple maggot flies
into some orchards in early June ~ just on the
tail end of curculio season. Active tunnels were
noted at this time, so we advised growers to base
sprays on trap captures and not wait until July
if the threshold was reached. There was a drop
in apple maggot fly pressure in most locations
after Hurricane Bob (August 20).
Calyx End Rot
This disease was not a severe problem this
year; however, it was present in nearly all of the
orchards we visited.
Black Rot
Frog eye leaf spot was common this year, and
more fruit injury than usual was noted.
•A* +1* *1* *i* *i*
*J» *f% rj* *J» *J*
8
Fruit Notes, Winter, 1992
Notching Increases Branching
on Apple Trees
Duane W. Greene and Wesley R. Autio
Department of Plant & Soil Sciences, University of Massachusetts
Frequently, a young apple tree does not
produce enough scaffold branches or secondary
lateral branches to fill the volume of its canopy
adequately. Chemical treatments can stimu-
late branching in these circumstances.
Promalin™ or one of its components,
benzyladenine, can be used to increase lateral
branching. Use of chemicals has not been
adopted widely by the industry, however, be-
cause it is difficult to regulate the number of
lateral shoots produced, and frequently, the
lateral shoots that are produced are too short to
develop into satisfactory scaffold branches.
Additionally, the rates of Promalin required to
stimulate lateral branching can thin developing
fruit and inhibit flower bud formation.
Cultural techniques also can increase
branching in young trees. Pruning into one-
year-old wood increases lateral branching; how-
ever, this type of pruning reduces the potential
fruiting surface, reduces flower bud formation,
and creates a cluster of branches near the cut
that have narrow, undesirable crotch angles,
limb spreading can stimulate lateral branch-
ing, but the numbers of branches produced are
very small. Leaf removal also increases branch-
ing, but to be effective, the youngest cupped
leaves surrounding the apical meristem must be
removed, and the lateral shoots that are pro-
duced by this method often are too short to be
useful. Bending terminal shoots to the horizon-
tal during the dormant season and then reposi-
tioning them later in the season is effective but
time-consuming. Also, bending is easy only in
certain situations, e.g., in trellis plantings
where there are wires for tying.
Another cultural technique which stimu-
lates lateral shoot development is notching.
Notching is defined as removing a section ofbark
above a vegetative bud. Removing this bark
prevents the flow of the growth-inhibiting hor-
mone auxin from the tip of a shoot or branch to
the notched bud. Under normal conditions,
auxins are produced in shoot tips and move
downward in stems preventing bud break and
growth of buds below. This process of inhibition
of lateral bud growth by vigorous shoots at the
Figure 1. The notching process. Bark
should be removed down to the wood in a 1/
16-inch band above the bud and extending
approximately one third of the way around
the branch. This figure was derived from
Oberhofer, H. 1990. Pruning the Slender
Spindle.
Fruit Notes, Winter, 1992
tips of branches or the central leader is called
apical dominance. Notching breaks apical domi-
nance and induces the bud to grow into a shoot.
Notching has been recommended occasion-
ally over the years by nomologists, extension
personnel, and growers; however, it has never
become a widespread commercial practice be-
cause of erratic and unpredictable results. Fac-
tors that influence the effectiveness of notching
never have been studied thoroughly. We specu-
lated that the inconsistent results with notching
may have been due to a lack of understanding of
the factors that affect bud growth following
notching. A series of experiments were carried
out during four years to identify factors that
influence the response of young apple trees to
notching.
All notching experiments were conducted at
the University of Massachusetts Horticultural
Research Center between 1986 and 1990.
Notching was done using an ordinary hacksaw
blade. Buds were notched by placing the blade
immediately above a bud and drawing the blade
horizontally across the branch. In this way a
strip of bark about 1/16-inch wide above the bud
was removed on about one third of the circumfer-
ence of the branch (Figure 1). It is important to
remove all bark down to the wood in this strip.
The following sections describe the results
from several experiments which asked specific
questions about notching.
Timing
In 1986, a block of Redspur Delicious/
MM. Ill was divided into 11 groups (replica-
70
S? 60
Notched
d> 50
c 40
MM
: / ^N
Si 3 °
\
o
-c 10
</>
Control
FB-6 FB-4 FB-2 FB FB+2
Time of notching
Figure 2. The effects of the timing of notching on shoot growth. Data represent the percent
of marked buds. This experiment was conducted in 1986 on Redspur Delicious/MM.lll.
10
Fruit Notes, Winter, 1992
50
40-
o 30-
CM
Al
CO
o
o
CO
20
10
Top
tions) of six trees each.
In mid-March, 12 buds
of similar size and lo-
cation were selected
and marked with
white paint. The
marked buds on one
tree in each group
were notched on
March 31, April 11,
April 23, May 8, or
May 22, about six,
four, or two weeks be-
fore anticipated full
bloom, at full bloom, or
two weeks after full
bloom, respectively.
Trees reached silver
tip on April 4, green tip
on April 10, and 1/2-
inch green on April 23.
Buds on one tree per
replication were not
notched and served as
the control. After
leaves dropped in November, all marked buds or
shoots were measured and the numbers of buds
with shoots two inches or longer were recorded.
Clearly, the optimum period of notching was
between two and four weeks before full bloom
(Figure 2). Notching done before or after this
time was less effective. We speculate that the
effectiveness of early notching was diminished
because the wound healed before significant
growth occurred, and the inhibitory effects of the
apical buds on lateral bud growth were reestab-
lished. We believe that late notching was less
effective because once growth starts in the
spring, the potential for an inhibited bud to grow
is reduced. The longer notching is delayed, the
less effect notching will have. The window for
the most effective period for notching is rather
narrow.
Position of Bud: Top vs Side vs.
Bottom of a Branch
In 1987, twenty Spigold/M.7 trees were se-
lected and paired into 10 groups (replications).
I Control
I Notched
Side
Bottom
Bud position
Figure 3. The effects of bud position (top, side, or bottom of branch)
on shoot growth with or without notching. Data represent the
percent of marked buds. This experiment was conducted in 1987 on
Spigold/M.7.
Ten buds each were selected randomly on the
top, side, and bottom of one-year-old portions of
scaffold limbs. All marked buds on one of the two
paired trees were notched on April 22 (2.5 weeks
before full bloom). Marked buds on the second
tree in each group were not notched, and served
as the control. The lengths of all marked buds
were measured after leaf drop in November.
Notching was most effective at inducing
shoot growth from buds on the top of a branch,
intermediately effective from buds on the side,
and least effective from buds on the underside of
a branch (Figure 3). This response generally
reflects the normal relationship of shoot growth
from buds in these positions; however, notching
enhanced that shoot growth dramatically.
Rarely would one choose to have a bud on the top
of a scaffold develop a shoot, because it would be
vigorous and unproductive. Even if desired,
very few buds on the lower side of a branch will
grow after being notched. Therefore, if lateral
branching is desired on scaffolds, notching
should be confined to buds on the sides of those
branches.
Fruit Notes, Winter, 1992
11
Position of Bud: Tip vs. Middle vs.
Base of a Shoot
In 1989, 60 three-year-old Marshall Mcln-
tosh/M.26 were grouped into 10 blocks (replica-
tions) of six trees each. One bud in the tip,
middle, and base of one-year-old and two-year-
old portions of the central leader were marked
with paint in March. The marked buds on three
of the six trees in each replication were notched
three weeks before full bloom. Buds on the
remaining three trees were not notched and
served as controls. Growth measurements were
made after leaf drop in November.
When buds were not notched, the most
shoots grew from those buds on the upper third
of one- or two-year-old growth, and very few
shoots developed from buds on the lower third
(Figure 4). Presumably, this relationship was
due to greater apical dominance imposed by the
shoot tip upon buds located on the lower portion
of a year's growth. If a bud was notched, it
appeared to make no difference where the bud
was located. Shoots grew equally well from
inches (%)
CO CO o
o o o
Notched
CM
Al 40
CO
O 20
CO
^\^^ Control
Tip Middle Base
Bud position
Figure 4. The effects of bud position (tip, middle, or bottom of a year's
growth) on The percent of marked buds achieving the desired growth
with or without notching. This experiment was conducted in 1 989 on
Marshall Mclntosh/M.26.
notched buds at the tip, middle, or base of a
year's growth.
Wood Age
The trees used in the previous experiment
were used to determine the effect of wood age on
the response to notching. The percent of notched
buds that developed into shoots was not influ-
enced by wood age (Figure 5). Notching was
equally effective on both one- and two-year-old
wood; however, a word of caution is in order.
Because one-year-old shoots are relatively small
in diameter, they can be broken during the
notching process unless extreme care is exer-
cised.
Bud Size
In 1990, 80 four-year-old Marshall Mcln-
tosh/M.26 were selected and grouped into eight
blocks (replications) of 10 trees each. One bud
that was less than 4 mm in diameter, one that
was between 4 and 5 mm, and one that was over
5 mm in diameter were selected in March on the
two-year-old portion
of the central leader.
Buds on five trees per
replication were
notched on April 20.
Buds on the remain-
ing five trees were not
notched and served as
controls. Growth
measurements were
taken as described
previously.
Size is an indica-
tion of bud vigor and
potential for vegeta-
tive growth. In this
experiment, small
buds that were not
notched did not pro-
duce shoots. Some
medium sized buds
produced shoots, and
large buds generated
the largest number of
shoots (Figure 6).
12
Fruit Notes, Winter, 1992
100
1 year 2 year
Wood age
Figure 5. The effects of wood age on shoot growth with or without
notching. Data represent the percent of marked buds. This experi-
ment was conducted in 1989 on Marshall Mclntosh/M.26.
100
inches (%)
0) 00
o o
yS Notched
CM
Al 40
*2
O 20
CO
Control ^^^^"^^^
Small Medium Large
Bud size
Figure 6. The effects of bud size on shoot growth with or without
notching. Data represent the percent of marked buds. This experi-
ment was conducted in 1990 on Marshall/Mclntosh/M.26.
Fruit Notes, Winter, 1992
13
Central Leader vs. Scaffold Branches Notching vs. No Notching
In 1987, 14 Spurcort/M.7 trees were paired
into seven blocks (replications). One bud was
marked with white paint at the tip, another in
the middle, and another at the base of one-year-
old wood on the central leader. Buds were
selected and marked in the same way on each of
four scaffold branches on each tree . Three weeks
before full bloom all marked buds on one tree per
replication were notched. Marked buds on the
remaining tree in each replication were not
notched and served as the control. Growth
measurements were taken as described previ-
ously.
The central leader is upright and generally
is the most vigorous portion of a tree. Scaffold
branches are frequently less vigorous because
they are positioned lower in the tree and they
originate on the central axis of a tree at an angle
of 45° or greater. Probably because of this
difference in vigor, un-notched buds of the cen-
tral leader tended to produce shoots more
readily than those of scaffold branches. Notch-
ing dramatically enhanced the shoot develop-
ment in both locations (Figure 7).
100
co
a>
o
c
CM
AJ
CO
o
o
Central leader
Branch type
Figure 7. The effects of notching on the central leader vs. scaffold
branches. Data represent the percent of marked buds. This
experiment was conducted in 1987 on Spurcort/M.7.
The overall effectiveness of notching for
stimulating shoot growth from buds was as-
sessed by pooling data collected in several ex-
periments performed during four years. Only
data taken from notching done at the proper
time and on the appropriate buds were included.
Notching increased the chance of a bud
growing into a lateral shoot by about 600%
(Figure 8). This success rate can realistically be
expected, since it was derived from information
collected over several years, on different types of
trees, on different cultivars, and under a wide
range of growing conditions.
Conclusions
We believe that notching is the most effec-
tive technique available to stimulate shoot de-
velopment on apple trees. The reasons for this
conclusion are as follows:
1. It is rapid. A bud can be notched with a
hacksaw blade in less than five seconds.
2. Buds can be stimulated to grow in areas
where they are wanted.
3. Growth, fruit set, and
flower bud formation
are not adversely af-
fected on other por-
tions of the tree.
4. Shoots that are
stimulated to grow
with notching fre-
quently are longer
than those induced
by other means.
Shoots that develop
from notched buds fre-
quently have a sharper
crotch angle than shoots
that develop from buds
that were not notched.
Angles can be improved
by using clothes pins or
weights; however, unless
angles are much below
50° from vertical, this
detrimental aspect of
Scaffold
14
Fruit Notes, Winter, 1992
notching will be of little practical consequence.
There are several key factors that must be
considered for notching to work effectively and
consistently:
70
Notched
Over all experiments
Buds must be notched within a relatively
narrow period of time. We suggest that the
time between green tip and 1/2-inch green is
most appropriate.
2. A sufficiently wide strip
of bark must be re-
moved to allow shoot
growth to occur before
the notched area heals.
3. The strip of bark re-
moved must extend far
enough around the cir-
cumference of the
branch to prevent influ-
ence of the apex on the
notched bud. Usually
removing bark from
about one third of the
circumference of the
branch and immedi-
ately above the bud is
sufficient.
4. The greatest success of
notching, i.e. the high-
est percent bud break
and the longest shoots,
will occur from large
buds or buds on vigor-
ous shoots such as the
central leader.
5. Because of the average
success rate of notching
of approximately 60 %,
Figure 8. The overall effects of notching on shoot growth. This
figure combines data from four years of experiments utilizing
several types of trees and different cultivars growing under
different conditions. Data represent the percent of marked
buds.
at least two buds
should be notched in a
specific location to im-
prove the chances of
getting the desired
branch.
**J^* *i* *!■* *i*
*J* *J% *Y» »j%
Fruit Notes, Winter, 1992
15
Second-level Apple Integrated Pest Management:
The Effects of Summer Pruning and a
Single Fungicide Application on
Flyspeck and Sooty Blotch
Daniel R. Cooley, Wesley R. Autio, and James W. Gamble
Departments of Plant Pathology and Plant & Soil Sciences,
University of Massachusetts
In a previous article [Fruit Notes 56(1):24-
26], we demonstrated that summer pruning
could reduce the incidence of flyspeck, a common
summer disease of apples. While it reduced the
incidence of flyspeck by half, summer pruning
alone did not reduce flyspeck to commercially
acceptable levels. Fungicides may be necessary
to give adequate control; therefore, we initiated
this experiment to determine the effectiveness
of summer pruning alone or in combination with
a single fungicide application at reducing the
incidence of flyspeck and sooty blotch.
In 1991, a group of mature Mclntosh/M.7
trees at the University of Massachusetts Horti-
Table 1.
Flyspeck and sooty blotch incidence (30-fruit sample)
on summer pruned and non-
summer
pruned trees treated with captan plus benomyl, capt
an alone
, or no fungicide.
Summer
Fungicide Flyspeck
Sooty blotch Total
pruning
treatment (%)
(%)
(%)
Moderately vigorous
trees
Yes
Captan + benomyl 3.7
ab*
0.3
b 3.9 ab
Captan 2.7
b
0.1
b 2.8 b
None 5.0
a
0.1
b 5.0 a
No
Captan + benomyl 2.4
b
0.1
b 2.5 b
Captan 2.7
b
0.1
b 2.8 b
None 5.2
a
0.8
a 6.0 a
Vigorous trees
Yes
Captan + benomyl 4.6
b
0.5
a 5.0 c
Captan 6.7
b
1.4
a 8.1 be
None 6.6
b
1.1
a 7.7 be
No
Captan + benomyl 7.8
b
2.0
a 9.9 ab
Captan 7.0
b
1.1
a 8.1 be
None 11.3
a
1.5
a 12.9 a
*Means within columns and tree-vigor classification not followed by a common letter are
significantly different at odds of 19 to 1.
16
Fruit Notes, Winter, 1992
cultural Research Center were partitioned into
seven blocks of six trees each. On July 22, two
trees in each block received a single mixed
fungicide application (2 lbs. Captan 50WP/100
gal. + 3 oz. Benomyl 50 DF/100 gal.), two trees
received a normal fungicide application (2 lbs.
Captan 50WP/100 gal.), and the remaining two
trees were not treated with fungicide. On Au-
gust 1, one of the two trees for each fungicide
treatment within each block was summer
pruned. Because of natural soil variation across
the field, trees in a portion of the blocks were
vigorous, with dense foliar canopies, while trees
within the remaining blocks were only moder-
ately vigorous, with fairly open canopies.
The results are shown in Table 1. The vigor
of the trees had a significant impact on the level
of sooty blotch and flyspeck. The more vigorous,
dense trees had more blemished fruit than the
open trees. For the moderately vigorous trees
with a relatively open canopy, additional sum-
mer pruning had no effect on sooty blotch and
flyspeck; however, if the canopy was dense,
summer pruning significantly reduced the total
disease incidence. Applying a single fungicide
treatment to dense trees or using summer prun-
ing decreased flyspeck by approximately the
same amount. No treatment significantly re-
duced sooty blotch in dense trees, but either
pruning or fungicide reduced the disease in open
trees.
Using a fungicide significantly reduced the
combined levels of sooty blotch and flyspeck;
however, there was no difference between the
two fungicide treatments. The combination of
fungicide and summer pruning generally was
better than either treatment alone in the trees
with dense canopies, but did not significantly
aid control in those trees with open canopies.
While some treatments significantly re-
duced disease, no treatment gave adequate com-
mercial control of flyspeck (less than 0.1%);
however, the application of fungicide was not
close enough to protect against a major rain
which occurred in mid-August. The time be-
tween the application of the fungicides and the
rain was 24 days, more than the three weeks
recommended for benomyl plus captan or the
two weeks recommended for captan alone. Next
season, we plan to time fungicide sprays accord-
ing to accumulated wetting hours, a technique
which has proven successful in North Carolina.
*«X» vl> *JL» vt>
»j» «Y» *J* *x*
Fruit Notes, Winter, 1992
17
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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Account No. 3-20685
54
Fruit Notes
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension System,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
ISSN 0427-6906
Volume 57, Number 2
SPRING ISSUE, 1992
Table of Contents
Increasing Fruit Size of Royal Gala
Second-level Integrated Pest Management
in 1991: Insects and Mites
Peach Pests I: Insects That Feed on Peach Fruit
Red Stele Resistant Strawberries and Their
Role In Epidemiology of Red Stele
M.OG1CM
2 4 1992
tBRARY Sampling for Early-season Leafminer Populations
£S in Massachusetts in 1991
Predicting Infections of Flyspeck on Apple
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 $7.00 for United States
addresses and $9.00 for foreign addresses. Each one-year subscription
begins January 1 and ends December 3 1 . Some back issues are available
for $2.00 (United States addresses) and $2.50 (foreign addresses).
Payments must be in United States currency and should be made to the
University of Massachusetts.
Correspondence should be sent to:
Fruit Notes
Department of Plant & Soil Sciences
205 Bowditch Hall
University of Massachusetts
Amherst, MA 01003
COOPERATIVE EXTENSION SYSTEM POLICY:
All chemical uses suggested in [his 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, nocompany endorsement or product discrimination
is intended. The University of Massachusetts makes no warranty or guarantee of any kind, expressed or implied,
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DAMAGE.
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furtherance of the acts of May 8 and June 30,1914. The University of Massachusetts Cooperative Extension System
offers equal opportunity in programs and employment.
Increasing Fruit Size of Royal Gala
Duane W. Greene, Wesley R. Autio, Joseph Sincuk,
James Krupa, and William J. Lord
Department of Plant and Soil Sciences, University of Massachusetts
Gala has rapidly risen in popularity to the
point where it is now one of the most heavily
planted apple cultivars in the world. It has
many desirable attributes including very high
quality, attractive appearance, precocity, and
high production. One of the major faults of this
cultivar is small fruit size. While prices in the
market for Gala generally are high, a premium
is paid for large fruit. We initiated several
studies specifically intended to investigate con-
ditions that may influence the size of Gala, with
the goal of identifying practices which may in-
crease Gala size.
Type of Fruiting Wood
It was suggested [American Fruit Grower
109(4):42-44, 1989] that the largest Gala apples
are borne terminally on short shoots (3 to 10
inches), that the smallest are produced on one-
year-old wood, and that those of intermediate
size are found on spurs of two-year-old wood. We
selected 29 five-year-old Royal Gala/M.26 trees,
and at normal harvest, we harvested from each
tree lateral fruit on one-year-old wood, terminal
fruit on shoots 6 to 10 inches long, and fruit
located on two-year-old spurs. Fruit from each
tree were weighed and the diameters were mea-
sured. Fruit located on one-year-old wood were
significantly smaller than those on other types
of wood (Table 1), a relationship that is common
in most apple cultivars. Fruit located terminally
on short shoots was of comparable weight and
diameter to fruit located on two-year-old spurs.
Gala normally produce some short shoots;
however, based on this study, there does not
appear to be a good reason to increase artificially
the number of short shoots on Gala, since fruit
borne on these shoots were no larger than fruit
on spurs. Efforts should be made, however, to
reduce the number of fruit on one-year old wood,
since fruit size on this wood was significantly
smaller. Fruit borne on the tips of branches
weigh down the branches, reducing growth and
light penetration into the interior of the tree and
lower branches. Fruit on one-year-old wood
ultimately reduce fruit quality and devitalize
fruiting spurs and short shoots. Strategies
should be developed to remove fruit on one-year-
old wood selectively.
Table 1. Relationships of fruit location on the tree and size at
harvest of Royal Gala apples.
Fruit
location
Fruit
diameter
(in)
Fruit
weight
(oz)
1-year wood
2-year wood
Short shoots
2.70 b
2.86 a
2.83 a
5.2 b
6.1 a
6.2 a
*Means within columns not followed by the same letter are
significantly different at odds of 19:1.
Fruit Notes, Spring, 1992
Table 2.
Bloom and fruit distribution on Royal Gala apple trees.
Year
Bloom
(clusters/in 2 limb cross-sectional area)
(fruit/in 2
Fruit set
limb cross sectional area)
Spur
Lateral Total
Spur
Lateral Total
1990
1991
63
66
123 186
127 193
44
77 121
Distribution of Flowering and
Fruit Set on Royal Gala
If the location of fruit influences fruit size,
then it is important to know the normal flower-
ing habit and fruit set distribution of Gala.
Royal Gala/M.26 planted in 1988 were used in
this study. In 1990, two branches per tree were
tagged and measured at bloom, and all of the
flowers on spurs and one-year-old wood were
counted. In 1991, bloom was determined simi-
larly but fruit set was also taken. Over two
thirds of all flowers on Royal Gala were produced
on one-year-old wood (Table 2). The location of
flowers was strikingly similar in the two years.
Fruit set was heavy in 1991. Although the
percent of flowers that set on one-year-old wood
was lower than that on spurs, following June
drop these fruit still represented nearly two
thirds of all of the fruit that set on these limbs.
For most cultivars the majority of flowers
are borne on spurs or terminally on short shoots.
On these cultivars, bloom on one-year-old wood
can vary significantly, depending upon the year,
but typically it does not constitute the majority
of the flowers on a tree. Gala is different in that
most of the flowering does occur as lateral bloom
on one-year-old wood and this lateral bloom sets
significant numbers of fruit. Bloom data pre-
sented here for Royal Gala were part of a larger
Gala strain trial. Bloom was determined simi-
larly on the others four strains included in this
trial. The distribution of bloom and fruit set was
similar for all strains. Therefore, the abnor-
mally large amount of lateral bloom and high
fruit set of these lateral fruit is typical for
standard Gala and several of its red coloring
strains.
Table 3. Effects of postbloom thinning treatments on fruit set and size of
Royal Gala apples.
Fruit set
Fruit
(fruit/in 2 limb
weight
Treatment*
cross-sectional area)
(oz)
Control
77
4.9
Sevin 1 lb + NAA ppm
44
5.9
Sevin 1 lb + NAA 3 ppm
34
6.1
Sevin 1 lb + NAA 6 ppm
29
6.4
*A11 thinning treatments were significantly different from the control at odds
of 99:1.
Fruit Notes, Spring, 1992
Thinning Treatments to
Increase Fruit Size
Adequate chemical thinning is a key compo-
nent in getting good fruit size and consistent
crops. Because the popularity of Gala has risen
so rapidly, there are very few mature Gala trees.
Therefore, we have not been able to establish a
chemical thinning recommendation for trees
growing in the Northeast. A block of six-year-old
Gala/M.26 were selected in 1991 and divided
into 14 groups of four trees each. When fruit size
was 3/8 to 1/2 in, one tree in each block was
sprayed with either 1 lb per 100 gal Sevin™, 1 lb
per 100 gal Sevin plus 3 ppm NAA, or 1 lb per 100
gal Sevin plus 6 ppm NAA. One tree in each
group was not sprayed and served as a control.
The number of fruit persisting in July was
counted on two limbs per tree. At the normal
harvest time 40 apples were harvested at ran-
dom from each tree and then weighed.
Trees that were not chemically thinned set a
heavy crop with small fruit size (Table 3). Sig-
nificant thinning occurred when Sevin alone
was used, although we do not believe that
enough fruit were removed. The addition of
NAA with the Sevin caused further thinning
which resulted in even larger fruit. Based upon
these data and observation of trees in this ex-
periment, we conclude that 1 lb per 100 gal of
Sevin plus 3 ppm NAA was the most appropriate
thinning treatment for trees in this block of
Royal Gala in 1991. We calculate that the
average fruit diameter of fruit from this treat-
ment was 2.9 inches.
Influence of Time on Fruit Size
It is generally believed that apple fruit
growth occurs at a relatively uniform rate
throughout the growing season. In the 60-day
period immediately before harvest fruit in-
crease in size by 0.8% to 1.0 % per day; however,
it was suggested (Fruit Varieties Journal 44:18-
22, 1990) that Gala may increase in size more
rapidly than other cultivars during the harvest
period. Ten fruit were tagged and the diameter
measured on eight Royal Gala trees in early
August and weekly for seven weeks. Fruit
diameter increase was curvilinear over the time
measured. When the fruit diameter was con-
verted to fruit weight with a standard curve,
growth rate was linear. Over the 54 days that
the fruit were measured, fruit weight increased
at an average rate of 1.2% per day. While this
rate of growth is greater than in other published
reports, it is only marginally greater and prob-
ably not statistically higher.
We do not believe that delaying harvest of
Gala is a viable way to achieve large fruit size.
Delaying harvest 10 days would produce a fruit
that weighs 12% more but the diameter would
increase by only 0.05 to 0.06 inches during that
period of time. There are also other factors to
consider. If left on the tree too long, Gala fruit
will crack, although, cracking has not been as
severe a problem in Massachusetts as it is re-
ported to be in other growing areas. In 1991,
Royal Gala were harvested on September 3, 12,
and 19. No cracking was noted on the first
harvest date, and only 1.1% of the fruit were
cracked at the two later dates. We estimate that
the optimum harvest date for Royal Gala on
these trees was September 15. Therefore, if fruit
are harvested at the proper time, very few fruit
will be cracked. When cracking does become a
problem, fruit maturity has advanced to the
point where the fruit feel 'greasy', and quality
has been diminished significantly. Gala has
been reported to require up to five harvests. If
trees are thinned properly and pruned to allow
good light exposure, we believe that Gala can be
picked in just two harvests.
Pruning and Training
Once Gala start to come into production they
can be pruned more severely than other culti-
vars. Gala flower and set fruit on more vigorous
and upright wood than most other cultivars.
Maintaining vigor in Gala assures production of
renewal spurs and sufficient spur leaf area and
shoot leaf area required for good fruit size.
Special efforts should be made to keep trees open
for good light penetration and to eliminate
weak, hanging wood that produces only small
inferior fruit and shades other areas of the tree.
Some summer pruning in August may be appro-
priate.
Fruit Notes, Spring, 1992
7.0
3
WEIGHT DIAMETER
□ — A—
""" ^/
2.9
6.3
2.8
,*— ^
N
O
27 §
g
5.6
DC
LU
2.6 uj
/a /^
^>
LU
<
4.9
2.5 | —
"H
CC
DC
LL
4.2
/ i i i i i
Li_
2.4
2.3
2.2
J "° 10 20 30 10 20 30
AUGUST SEPTEMBER
PigUT€
s 1. Royal Gala fruit growth through August and September.
Conclusions
Most flowers on Gala are produced on one-
year-old wood, and a significant number of these
set fruit. Since these fruit are small and their
presence influences tree structure and the qual-
ity of other fruit on the tree, a special effort
should be made to remove these early in the
season. A combination of Sevin and 3 ppm NAA
was considered the most appropriate chemical
thinning treatment on Royal Gala in 1991. Once
fruit have reached proper maturity, Gala should
not be allowed to remain on the tree to obtain
additional size. Trees should be pruned to allow
good light penetration and assure continued
development of new fruiting wood.
Fruit Notes, Spring, 1992
Second-level Integrated Pest
Management in 1991:
Insects and Mites
Margaret Christie, Kathleen Leahy, Jennifer Mason,
Jennifer Jaros, Jennifer Taylor, and Ronald Prokopy
Department of Entomology, University of Massachusetts
James Gamble
Department of Plant Pathology, University of Massachusetts
Over the past 4 years in Fruit Notes, we have
reported the results of our trials with first-level,
second-stage integrated pest management
(IPM) for insects and mites in Massachusetts
orchards. First level, second-stage IPM involves
the integration of several methods of control-
behavioral, ecological, biological and pesticidal-
-of a single class of pests. In 1991, in Massachu-
setts, we began a 4-year trial of second-level
IPM, in which orchard management is inte-
grated across all classes of pests: insects, mites,
diseases, weeds, and vertebrates. Last spring,
in Fruit Notes [56(2):13-15], we explained the
principles of second-level apple IPM, and here
we report results of the first year of second- level
IPM trials on insects and mites. A recent article
[Fruit Notes 57(1):16-17] reported on second-
level IPM trials on diseases.
Insect and mite management under second-
level IPM requires application of three to four
selective insecticide sprays from April to early
June to manage plant bugs, sawflies, plum
curculios, fruitworms, and the first generations
of codling moths, lesser appleworms,
leafminers, and leafhoppers. Insecticide appli-
cation to the interior of the block ceases after
early June, allowing natural populations of
predatory insects and parasitoids to increase to
levels sufficient to provide control of summer
populations of foliar pests. Apple maggot flies
are controlled by perimeter traps in full second-
level blocks, or by perimeter row sprays in tran-
sitional second-level blocks. Removal of
unmanaged apple and pear trees within 100
yards of each block reduces immigration of co-
dling moths and lesser appleworms. Removal of
drops after harvest discourages buildup of
within-orchard populations of apple maggot
flies, codling moths, and lesser appleworms.
In early April of 1991, we selected 12 test
blocks of six to nine acres each. The primary
apple cultivar was Mcintosh, but blocks in-
cluded Cortland, Delicious, Empire, and other
cultivars as well. Six of the 12 test blocks were
full second-level IPM blocks. Six were transi-
tional second-level blocks, using some but not all
of the practices of full second-level blocks. Each
second-level block was matched with a nearby
control block which was managed by the grower
using first-level IPM methods, in which treat-
ment decisions are based on monitoring and
pesticides are the primary treatment.
Full Second-level IPM
Early Season Management. For control
of pests active up to early June, second-level
IPM relies on early season pesticide treatment
based on monitoring. We monitored each or-
chard weekly beginning in mid-April, then
changed to biweekly from mid-June through
September. Five each of three types of sticky
traps were hung in each block to monitor for
tarnished plant bug (TPB), leafminers, and
Fruit Notes, Spring, 1992
Table 1. Average percent injury by early season insect pests in second-level vs. first-
level IPM blocks. 1 - 2
Type of block
TPB
PC
EAS
GFW
Total
Full second-level IPM
First-level IPM
Transitional second-level IPM
First-level IPM
4.1 a
7.1a
4.8 a
3.5 a
1.2 a
0.8 a
0.3 a
0.1b
0.1a
0.1 a
0.0 a
0.1a
0.0 a
0.0 a
0.0 a
0.0 a
5.4 a
8.0 a
5.1a
3.7 a
'TPB = tarnished plant bug; PC = plum curculio; EAS = European apple sawfly; GFW
= green fruitworm.
2 Means in each couplet in each column followed by a different letter are significantly
different at odds of 19:1.
European apple sawfly (EAS). We examined
100 or 200 leaves or terminals per block for
leafminers (eggs and mines), leafhoppers, mites,
and mite predators. Fruit were examined by
both IPM scouts and growers for fresh plum
curculio (PC) injury. Based on this monitoring,
recommendations were made to the grower for
treatment of the experimental block. Combined
injury from early season fruit pests was similar
in first- level IPM (grower control) blocks and in
Table 2. 1991 Insecticide and acaricide use in four types of blocks. Data presented are dosage
equivalents per blocks, with the number of spray events in parentheses. 1,2
Fruit
Before
pests Mites
After Before
After
Type of block
early
June
early early
June June
early
June
LH
ABLM
GAA
Total
Full second-
2.0 a
0.3 a 1.9 a
0.6 a
0.4 a
0.8 a
0.0 a
6.0 a
level blocks
(3.2)
(0.3) (2.7)
(1.0)
(0.6)
(1.2)
(0.0)
(9.0)
First-level
2.1 a
1.0 b 1.9 a
0.9 a
0.3 a
0.2 b
0.0 a
6.4 a
(3.3)
(1.8) (2.5)
(1.2)
(0.8)
(0.3)
(0.0)
(9.9)
Transitional
second-level
2.4 a
0.5 a 1.1 a
0.9 a
0.2 a
1.4 a
0.0 a
6.5 a
blocks
(2.5)
(2.7) (2.2)
(1.2)
(0.3)
(1.5)
(0.0)
(10.4)
First-level
2.1 a
1.6 b 1.5 a
2.3 b
0.1a
0.8 a
0.3 a
8.7 b
(2.7)
(3.2) (2.9)
(2.3)
(0.5)
(1.0)
(0.3)
(12.9)
1 LH = leafhopper; ABLM = apple blotch leafminer; GAA
2 Means in each couplet in each column followed by a
different at odds of 19:1.
= green apple aphid mite,
different letter are significantly
Fruit Notes, Spring, 1992
Table 3. Season-long apple maggot fly (AMF) injury and trap captures in two types of
full second-level IPM blocks, in transitional second-level IPM blocks, and in first-level
IPM blocks. 1
Type of block
AMF
injury
(%)
Interior
monitoring trap
captures
(per trap)
Outer
monitoring
trap captures
(per trap) 2
Interception
trap captures
(per block)
Second-level blocks with
ammonium carbonate
and butyl hexanoate
0.2 a
8.5 a
18.8 a
3562
First-level
0.3 a
16.8 a
38.7 a
Second-level blocks with
butyl hexanoate alone
0.6 a
14.5 a
11.8 a
2936
First-level
0.1b
9.5 a
7.2 a
Transitional second-level
blocks
0.3 a
4.5 a
7.0 a
First-level
0.3 a
3.5 a
4.4 a
J Means in each couplet in each column followed by a different letter are significantly
different at odds of 19:1.
^hese traps were positioned two rows inside the perimeter.
full second-level IPM (test) blocks (Table 1). In
both types of blocks, tarnished plant bugs
caused the greatest amount of injury, followed
by plum curculio, European apple sawfly, and
green fruitworm. Pesticide use against early
season fruit pests was very similar in second-
level and first-level blocks, probably because
most growers based their treatment of first-level
IPM blocks on monitoring (Table 2).
Summer Fruit-injuring Pests. Odor-
baited sticky red spheres were hung every 5
yards on perimeter apple trees of each experi-
mental block to intercept immigrating apple
maggot flies (AMF). In three of the blocks, these
were baited with butyl hexanoate, a synthetic
fruit odor. In the other three blocks, traps were
baited with both butyl hexanoate and ammo-
nium carbonate, a synthetic food odor.
Interception trap captures averaged 2936
per block in the three full second-level blocks
where synthetic fruit odor alone was used, indi-
cating high AMF pressure (Table 3). Captures
of AMF on four interior unbaited red spheres
(indicative of AMF penetration into the block
interior) averaged 34% more in second-level
blocks baited with fruit odor alone than in
nearby first-level blocks. AMF injury in these
second- level blocks was also slightly higher than
in nearby first-level blocks (0.6% vs. 0.1%). In
one of the three second-level blocks baited with
butyl hexanoate alone, interior monitoring trap
captures in early August suggested sufficient
AMF penetration to warrant pesticide treat-
ment. Hence, Guthion™ was applied on August
6.
In the three full second-level blocks baited
with butyl hexanoate and ammonium carbon-
ate, interception trap captures averaged 3562
per block, again indicating high AMF pressure.
Fruit Notes, Spring, 1992
Table 4. Fruit pest injury in second-level vs. first-level IPM blocks
1.2
Fruit damage (%)
Type of block CM 3
LR 3 LAW 4
SJS 4
Full second-level <0.1a
0.2 a 0.0 a
0.0 a
First-level <0.1a
0.2 a 0.0 a
0.0 a
Transitional
second-level < . 1 a
0.2 a 0.0 a
0.0 a
First-level <0.1a
0.1a 0.0 a
0.1 a
'CM = codling moth; LR = leafroller; LAW
= lesser apple worm ; SJS = San Jose
scale.
2 Means in each couplet in each column
followed by a different letter are
significantly different at odds of 19:1.
3 Average injury in season-long monitoring.
4 Average injury in harvest monitoring.
Even so, captures of AMF on four interior
unbaited red spheres per block were almost 50%
lower in second-level blocks baited with the two
types of odor than in nearby first-level blocks.
AMF injury in these three second-level blocks
was similar to nearby blocks. The very large
number of AMF caught on interception traps
coupled with the excellent degree of AMF control
obtained in blocks trapped with both synthetic
food and fruit odor suggests that this double-
odor trapping procedure may be very effective
for large (six to nine acres) blocks. We need,
however, to improve upon the type and distribu-
tion method of the synthetic food odor.
Fruit injury by codling (CM) moth averaged
less than 0. 1% in all block types, indicating that
CM injury did not increase in second-level blocks
where host trees within 100 yards of the block
perimeter were removed as a substitute for
summer insecticide use against this important
pest (Table 4). Leafroller (LR) injury averaged
0.2% in both full second-level blocks and nearby
first-level blocks. We will continue to monitor
carefully for leafroller because of concern that
leafroller populations may grow in blocks in
which the interior is not sprayed throughout the
summer. No lesser appleworm injury was found
on any sampled fruit.
The effects of removing drops from the or-
chard on populations of AMF, CM, and lesser
appleworm of removing drops from the orchard
will not be apparent until next year; however,
our experience with first-level, second-stage
IPM from 1987-1990 suggests that a no-spray
approach after early June may not succeed
unless all integrated management techniques
are adopted. We continue to believe that re-
moval of drops is an essential component of
second-level IPM.
Fewer dosage equivalents of pesticide were
applied against summer fruit pests in second-
level blocks than in first-level blocks (0.3 vs. 1 .0),
but pesticide use was also low in first-level
blocks (Table 2). This may be explained by the
use of low rates of Guthion™ and the use of
monitoring traps. In one case the threshold for
treatment of AMF was never reached and no
mid-season insecticide was applied in the first-
level block (Table 3).
Foliar Pests and Predators. The second-
level approach of allowing natural enemies to
build in the absence of insecticide use after early
8
Fruit Notes, Spring, 1992
June was less effective in managing two key lations, which in some cases were not checked
foliar pests, mites and leafhoppers, than key sufficiently by predators (Table 5). Although
fruit-attacking pests. The summer's hot, dry Amblysieus fallacis predators grew somewhat
weather contributed to the growth of mite popu- late in the summer, their numbers were not
Table 5. Mites and mite predators in
second-level vs. first-level IPM blocks. 1,2
Type of block
Sampling
date
Average percentage of leaves with:
ERM+TSM Af YM
Ratio of
ERM+TSM
toAf
Full second-level blocks:
Second-level
First-level
Early July
20.1
19.7
a
a
0.0
0.0
a
a
0.2 a
0.0 a
20:0 a
20:0 a
Second-level
First-level
Mid July
37.8
37.4
a
a
0.5
0.6
a
a
0.9 a
0.8 a
76:1 a
62:1 a
Second-level
First-level
Late July
56.3
48.3
a
a
1.4
1.3
a
a
0.4 a
0.7 a
40:1 a
37:1 a
Second-level
First-level
Early Aug.
60.1
31.6
a
a
4.1
2.3
a
a
1.9 a
1.6 a
15:1 a
14:1 a
Second-level
First-level
Late Aug.
13.4
8.8
a
a
4.8
0.6
a
a
4.8 a
1.5 a
3:1 a
15:1 a
Second-level
First-level
Early Sept.
12.4
12.3
a
a
0.3
0.5
a
a
8.5 a
8.8 a
41:1 a
25:1 a
Transitional second-level blocks:
Second-level
First-level
Early July
27.0
17.1
a
a
1.3
0.3
a
a
0.1 a
0.1 a
20:1 a
15:1 a
Second-level
First-level
Mid July
17.3
22.4
a
a
3.4
0.6
a
a
0.1 a
0.0 a
5:1 a
39:1 a
Second-level
First-level
Late July
21.5
26.8
a
a
2.6
0.6
a
a
0.1 a
0.1 a
8:1 a
46:1 a
Second-level
First-level
Early Aug.
12.4
29.3
a
a
2.3
4.2
a
a
0.3 a
0.3 a
6:1 a
7:1 a
Second-level
First-level
Late Aug.
7.0
13.3
a
a
0.8
1.2
a
a
2.7 a
1.2 a
8:1 a
11:1 a
Second-level
First-level
Early Sept.
11.2
11.7
a
a
0.2
0.0
a
a
0.8 a
0.0 a
66:1 a
12:0 a
'ERM = European red mite; TSM = two-spotted mite; Af ' = Amblysieus fallacis; YM =
yellow mite.
2 Means in each couplet in each column followed by a different letter are significantly
different at odds of 19:1.
Fruit Notes, Spring, 1992
great enough to maintain mites below injurious quired treatment with Dimilin™ against sec-
levels in some second-level blocks. Not until late ond-generation leafminers. Leafminer popula-
August did the ratio of pest mites to Amblysieus tion levels throughout the summer confirmed
fallacis predators drop below 5:1, indicating our previous conclusion that application of
that there was a probability for biocontrol. Mi- Dimilin™ against the overwintering generation
ticide was recommended and applied early in of leafminer adults, when indicated by trap
the summer in several second-level blocks to captures, is the most effective and least invasive
prevent mite outbreaks (Table 2). Further technique for their control. In 1991, permission
study is needed of additional factors that can to use Dimilin™ in second-level blocks was not
contribute to predator buildup in the absence of granted until it was too late to treat the overwin-
post-May insecticide treatment. tering generation. Treatment of second-genera-
Both potato and white apple leafhopper tion adults and eggs is more difficult to time, and
population levels on terminals were slightly, but was not successful in one of the second- level
not significantly, higher over the course of the blocks. Nonetheless, the season-long average
season in second-level than in first-level blocks number of mines on 100 leaves was slightly, but
(Table 6). White apple leafhopper outbreaks not significantly, lower in second-level than in
occurred in two full second-level blocks, result- first-level blocks (26 vs. 33) (Table 6). Treat-
ing in 33% injured fruit in one block. Further ment with Dimilin™ is preferable to use of other
examination of the patterns of leafhopper materials which are harsher on beneficial in-
buildup is needed in order to better predict sects and mites. Several growers chose not to
outbreaks such as these. treat leafminers in their first-level blocks, where
Early season trap captures indicated that all Dimilin™ could not be applied. Consequently,
but one of the six full second-level blocks re- dosage equivalents of pesticide applied against
Table 6. Foliar insect pest population and injury levels in second-level vs. first-level IPM
blocks. 12
PLH WALH
Type of block PLH 3 injury 4 WALH 3 injury 5 ABLM 6 WAA 7 GAA 7 GAAP 7
Full
second-level 8.9a 16.6a 4.1a 4.2a 25.5 a 20.7a 72.8 a 68.7 a
First-level 6.8a 11.2a 1.0a 1.1a 33.1a 17.0a 70.2 a 58.9 a
Transitional
second-level 5.8 a 7.0 a 5.7a 5.8 a 38.9 a 13.7 a 47.5 a 29.5 a
First-level 1.6 a 12.2 a 1.5a 0.3 a 64.6 a 17.5 a 37.9 a 18.2 a
•PLH = potato leafhopper; WALH = white apple leafhopper; ABLM = apple blotch
leafminer; WAA = wooly apple aphid; GAA = green apple aphid; GAAP = green apple aphid
predators: cecidomyiids and syrphids.
2 Means in each couplet in each column followed by a different letter are significantly
different at odds of 19:1.
Percentage of terminals and watersprouts examined.
4 Percentage of terminals examined.
Percentage of fruit examined at harvest.
6 Average number of mines on 100 leaves.
Percentage of watersprouts examined.
10 Fruit Notes, Spring, 1992
Table 7. Numbers of spiders
vs. first-level IPM blocks. 1
captured by tapping
2 limbs in
each of 20 trees in second-level
Type of block
Mid
June
Early
July
Mid
July
Late
July
Early
Aug.
Late
Aug.
Early
Sept.
Full
second-level IPM
First-level IPM
Transitional
second-level IPM
First-level IPM
2.8 a
1.7 a
2.2 a
2.0 a
3.0 a
3.0 a
1.8 a
1.2 a
3.7 a
6.3 a
5.8 a
3.8 a
10.7 a
7.8 a
7.2 a
4.5 a
6.8 a
8.2 a
10.2 a
6.0 a
11.9 a
8.0 a
20.3 a
2.0 b
11.3a
13.8 a
10.7 a
3.5 b
'Means in each cou
at odds of 19:1.
plet in each column
followed by.
i different letter are significantly different
leafminer were higher in second-level than in
first-level blocks (Table 2).
Green apple aphids infested 73% of sampled
terminals in full second-level blocks and 70% in
nearby first-level blocks when sampled in early
July (Table 5). Two aphid predators, syrphid
and cecidomyiid flies, averaged 69% in full sec-
ond-level blocks and 59% in nearby first-level
blocks. These high levels of predation indicate
that predators achieved control of green apple
aphids in both second-level and first-level IPM
blocks. Infestation of terminals by wooly apple
aphid was similar in second-level and in first-
level blocks (21% and 17%, respectively).
Little is known about the effects of spiders in
orchards, but they may play a role as predators,
particularly under conditions of reduced pesti-
cide applications. Spiders were monitored by
jarring limbs of trees with a rubber mallet and
catching any spiders that fell in a tray held
beneath the branch. Although the number of
spiders caught increased as the summer pro-
gressed, the numbers caught in the full second-
level blocks never differed significantly from
those captured in nearby first-level blocks
(Table 7). This similarity may be explained by
the patterns of insecticide and miticide use in
the two blocks, explained below.
Total insecticide and miticide use in full
second-level blocks was only slightly lower than
in nearby first-level blocks (6.0 vs. 6.4 dosage
equivalents) (Table 2). This result contrasts
with pesticide records from previous years,
when an average of about 9 dosage equivalents
of insecticide and miticide were applied to first-
level IPM blocks. (In this study in 1991, 8.7
dosage equivalents were applied to first-level
IPM blocks paired with transitional second level
blocks.) Several factors contributed to an in-
crease in pesticide use in second-level blocks,
including the hot, dry weather which contrib-
uted to mite buildup, a hawthorn tree on the
edge of one block which contributed to high AMF
trap captures, and lack of treatment of some
nearby blocks. Other factors, including the
increased monitoring resulting from this project
and the lack of an attractive insecticidal option
for leafminer control, caused a decrease in pes-
ticide use in first-level blocks.
Transitional Second-level IPM
Early Season Management. Monitoring
in transitional second-level blocks was identical
to that conducted in full second-level blocks.
Combined injury from tarnished plant bug,
plum curculio, European apple sawfly, and
green fruitworm averaged 5.1% in transitional
second-level blocks and 3.6% in first-level blocks
(Table 1). Pesticide use against early season
pests was similar in the two types of blocks
(Table 2).
Fruit Notes, Spring, 1992
11
Summer Fruit-injuring Pests. Every
three weeks after early June, perimeter row
apple trees in transitional second-level blocks
were treated with insecticide to control AMF.
The block interior remained free of insecticide
after early June. AMF injury averaged 0.3% in
both the transitional second-level blocks and the
nearby first-level blocks (Table 3). AMF cap-
tures on interior monitoring traps indicated that
in most cases few AMF penetrated into the
orchard interior. In one second-level block,
however, trap captures in early August sug-
gested that AMF penetration warranted a full
block spray, which was applied August 8.
Unmanaged apple and pear trees were re-
moved from within 100 yards of the six transi-
tional second-level blocks and, as in the full
second-level blocks, codling moth injury aver-
aged less than 0.1% in both transitional second-
level blocks and nearby first-level blocks.
Leafroller injury was slightly, but not signifi-
cantly, higher in the transitional second-level
blocks than in the first-level blocks (0.2% vs.
<0.1%). Growers applied about three times as
much insecticide against mid-season fruit pests
in first-level blocks as in transitional second
level blocks (1.6 vs. 0.5 dosage equivalents)
(Table 2).
Foliar Pests and Predators. In the tran-
sitional second-level blocks, average numbers of
pest and predatory mites were present in ratios
indicating that adequate control was likely dur-
ing much of July and August (Table 5). In each
case, however, predatory mites were present in
high numbers in only one of the six transitional
blocks. In several blocks, miticides were recom-
mended and applied in order to avoid a mite
outbreak (Table 2).
Both white apple and potato leafhopper in-
festation levels on terminals and white apple
leafhopper injury to fruit averaged slightly but
not significantly higher in transitional second-
level blocks than in nearby first-level blocks
(Table 6).
All six transitional second-level blocks were
treated with Dimilin™ against second genera-
tion leafminers. The season-long average num-
ber of leafmines on 100 leaves was 39 in second-
level blocks and 65 in first-level blocks.
Green apple aphids infested an average of
48% of terminals in transitional second-level
blocks and 38% of terminals in nearby first-level
blocks in July. Predators were found on an
average of 30% of terminals in transitional sec-
ond-level blocks and 18% of terminals in first-
level blocks. Although levels of green apple
aphids were slightly higher in second-level
blocks than in first-level blocks, higher levels of
predation indicated adequate biocontrol of
aphids. Similar percentages of terminals in the
transitional second-level blocks and in first-
level blocks were infested with wooly apple
aphids (14% and 18%, respectively). None of the
differences in aphid population levels were sta-
tistically significant.
Spider monitoring in the transitional sec-
ond-level blocks indicated that by late summer
the numbers of spiders in the second-level block
were significantly higher than the numbers in
the nearby first-level block (Table 7). In mid
June, an average of about two spiders was
captured in both types of block, but by late
August there were an average of 20 spiders
captured in second-level blocks and only two in
first level blocks. Insecticide and miticide use in
first-level blocks near transitional second-level
blocks was higher than in any other type of
block, and this may explain the low number of
spiders found in these blocks.
A significantly greater number of dosage
equivalents of pesticide was applied in first level
blocks than in second-level blocks (8.7 vs. 6.5)
(Table 2).
Conclusions
In conclusion, we generally are pleased with
our first year trials of second-level IPM manage-
ment practices for insects and mites. Despite
the increase in block size from two to three acres
under first-level, second-stage IPM to six to nine
acres under second-level IPM, control of AMF
through both interception traps and perimeter
row spraying was generally successful. The
addition of ammonium carbonate as a food odor
bait shows promise for future AMF interception
trap strategies. Early season injury from plum
12
Fruit Notes, Spring, 1992
curculio, tarnished plant bug, European apple
sawfly, and green fruitworm was not signifi-
cantly different in full second-level blocks than
in nearby first-level blocks; in transitional sec-
ond-level blocks, only plum curculio injury was
slightly higher than in nearby first-level blocks.
Codling moth, leafroller, lesser appleworm and
San Jose scale levels remained low in all blocks.
Green apple aphids were controlled by predators
in both types of second-level blocks. Transi-
tional second-level IPM continues to appear to
be a viable first step for growers who wish to
manage insect and mite pests with reduced
orchard spray schedules. Our first year of trials,
however, has pointed out several areas needing
further work: interactions between mites and
mite predators, better knowledge of leafhopper
population dynamics, and the potential role of
spiders in providing some control of leafhoppers.
After a full season of work, we are better-pre-
pared to address these issues and to assess the
long-term impact of second-level IPM over the
next three years.
Acknowledgements
This project was funded by the Massachu-
setts Society for Promoting Agriculture, the
USDA Northeast Regional IPM Competitive
Grants Program, and the Massachusetts Fruit
Growers Association. We gratefully acknowl-
edge this funding. We are also grateful for the
participation and support of the following grow-
ers: Bill Broderick, Bruce Carlson, Dave Chan-
dler, Dana Clark, Dick Gilmore, Tony Lincoln,
Wayne Rice, Tony Rossi, Joe Sincuk, Dave
Shearer, Tim Smith, Barry Wiles, and Bud
Wiles.
Fruit Notes, Spring, 1992
13
Peach Pests I:
Insects That Feed on Peach Fruit
Karen I. Hauschild
University of Massachusetts Cooperative Extension System
In Massachusetts there are several insect
species that feed on developing peaches. Two
types of damage result from this feeding: surface
scarring and the resulting malformation (com-
monly referred to as "catfacing") and larval
tunneling into fruit flesh. Injured fruit either
drop prematurely or are downgraded in the
sorting process.
Fruit scarring is caused by two groups of
insects in the order Hemiptera, the "true bugs."
The tarnished plant bug and a complex of true
bugs known as the oak-hickory plant bugs feed
on young, developing peaches with resulting
damage appearing as dimpling or surface scar-
ring. Several species of stink bugs cause similar
damage. Most serious damage occurs between
petal fall and when fruits are 1/2 to 3/4 of an inch
in diameter.
The oriental fruit moth, plum curculio, and
walnut husk fly lay eggs in developing fruit. If
these eggs hatch, larvae then tunnel in fruit
flesh, a type of damage that results in fruit drop
or non-marketability.
Below is a brief description of the biology of
each of these pests, the damage each causes, and
basic information on non-chemical control.
Catfacing Insects
Tarnished Plant Bug. The tarnished
plant bug (Lygus lineolaris) is a small, 1/4-inch
long, golden to brown bug with white and yellow
markings. Adult tarnished plant bugs overwin-
ter in hedgerows, in leaf litter, under tree bark,
and in other protected areas in and around
orchards. Plant bugs emerge early in spring,
and feed on buds as they begin to swell. If
damage is severe, developing fruit buds will dry
up and drop off. If damage occurs to blossoms or
young fruit, catfacing, scarring, or dimpling will
result.
Tarnished plant bug damage usually is most
serious following mild winters, in areas bor-
dered by woodlands or fields, and in orchards
next to fields of alfalfa or ones with a high
population of alfalfa plants in the ground cover.
White, rectangular sticky traps hung low in
peach trees can be used to monitor tarnished
plant bugs in peach orchards. At the present
time there is no economic threshold level, but
presence/absence can be used to indicate the
need for chemical control.
Oak-hickory Plant Bugs. Three species of
the genus Lygocoris - L. caryae, the hickory
plant bug; L. quercalbae, the white oak plant
bug; and L. omnivagous — are commonly re-
ferred to as the oak-hickory plant bugs. All
appear similar to the tarnished plant bug -
brown to yellowish-brown in color, but without
the tarnished appearance. These insects over-
winter as eggs on oak, hickory, and other tree
species. Adults migrate to peach in early June,
a few weeks after shuck split, with peak num-
bers appearing in mid-June. Adults apparently
do not live in peach trees, but seem to pass
through in an unpredictable pattern. Oak-
hickory plant bug damage results in catfacing -
sunken, scabby, oozing scars.
Rectangular pink (Pittsburgh "Pink Tiara")
traps placed high in the peach tree canopy can be
used to monitor presence and numbers. No
economic threshold level has been established.
Stink bugs. Several species of stink bugs
cause catfacing injury to peaches. Acrosternum
hilare, the green stink bug; Euschistus spp., the
brown stink bug; and Thynata spp. all have been
found in peach orchards. These insects are
shield-shaped, flattened, with narrow heads
and short legs. When disturbed, they emit a
14
Fruit Notes, Spring, 1992
characteristic, pungent odor. Adults overwinter
in plant debris or in hedgerows. Adults, depend-
ing on which species is present, appear from
petal fall to harvest.
Damage to peaches by stink bug feeding can
be dimpling, scarring, catfacing, or gummosis
(oozing scars).
Populations of stink bugs are higher in peach
orchards that are weedy or are bordered by
wooded areas. A grassy orchard floor and weed-
free understory help reduce stink bug popula-
tions. Mow after an insecticide application, as
mowing drives stink bugs up into trees.
Although there are numerous insect pests
that cause catfacing damage, often the causal
agent can be determined by noting the time at
which the injury occurred, and narrowing the
source to one or two insect species.
Insects Whose Larvae Tunnel
in Fruit
Plum Curculio. The plum curculio
(Conotrachelus nenuphar) is a small, brown,
bumpy snout beetle about 1/4 inch long. Larvae
are white to yellow, legless, brown-headed
"grubs" about 3/8 inch long.
Adult plum curculios overwinter in ground
litter, hedgerows , or other protected areas . They
become active after several warm days (>55°F),
usually at or around bloom. Adults begin feed-
ing on flowers and their activity peaks at about
12 to 14 days after petal fall. At this time,
feeding injury appears as small, round holes
which expand with growing fruit. Also, female
curculios deposit their eggs in small peaches,
after which they make crescent-shaped cuts
around the egg-laying sites. If eggs hatch, larvae
bore into the fruit, usually feeding around or
near fruit pits for up to three weeks. Full-grown
larvae drop from fruit to pupate in the soil.
Monitor for plum curculios by scouting for
adults or fresh fruit damage. Watch trees in
border rows and rows near wooded areas. Beat-
ing traps may also be used to monitor for adults.
Oriental Fruit Moth. The oriental fruit
moth (Grapholitha molesta) is a grey, 1/4-inch
long bug with dark brown wing bands. Early
season damage occurs on growing shoot termi-
nals, but second and third generation larvae
feed on and develop in peach fruits.
Oriental fruit moths overwinter as full-
grown larvae in crevices on trees or in the
ground cover. Adults emerge around the time of
peach bloom or in early May. Small, flat, oval,
disc-shaped eggs are laid on upper leaf surfaces
on terminal foliage. Full-grown larvae are 1/4-
to 5/16-inch long, pinkish in color with a brown
head and legs. Second- and third-generation
(early July to early August) larvae enter fruit,
resulting in gummosis and a black blotch on the
fruit at harvest. Half of the third generation
larval damage occurs when the larvae enter a
peach stem and move into fruit. Larvae, once
inside the fruit, feed to the pit. Oriental fruit
moth larvae leave peaches through holes
chewed in the sides of the fruit. These exit holes
are often marked by the presence of "gum" and
dark-colored blotches.
Oriental fruit moths can be monitored by
using pheromone traps. Pheromone disruption
techniques have been used to control this pest.
Good orchard sanitation — mainly removal of
fruit drops and shallow cultivation of the or-
chard floor before bloom to destroy overwinter-
ing larvae - will decrease the incidence of this
pest.
Walnut Husk Fly. The walnut husk fly
(Rhagoletis suavis) is a small picture-winged fly,
somewhat larger than the apple maggot, and
with a browner body. This insect feeds primarily
on native nuts such as shagbark or pignut
hickory, and occasionally is troublesome on
nearby peaches in years when native nut popu-
lations are low.
Adult walnut husk fly females lay eggs in
peaches, leaving an injury that is about two mm
round, depressed and retaining a green color as
the fruit develops. Often ooze is present. If
injured peaches are cut open, tunnelling is evi-
dent.
This minor pest occurs in peach orchards
with neighboring nut trees, especially during
years with poor nut crops. Adults have been
captured on several types of sticky traps, but no
economic threshold level has been determined.
Fruit Notes, Spring, 1992
15
For additional information on any of these 159 R 1991-2.
pests, please refer to:
Prokopy, R. J., P. J. Powers, D. R. Cooley, and J.
W. Gamble. 1991. Peaches, Pears, Plums - Pest
Control Guide for Commercial Growers in
Southern New England. Univ. of Massachu-
setts Cooperative Extension System Circular C-
Myers, S. C. (ed.) 1989. Peach Production
Handbook. Univ. of Georgia Cooperative Exten-
sion Service.
Peach Pests II (appearing in the next issue of
Fruit Notes) will discuss foliage and wood feed-
ing insect pests.
Red Stele Resistant Strawberries
and Their Role in Epidemiology
of Red Stele
Shahrokh Khanizadeh
Agriculture Canada St-Jean-sur-Richelieu, Quebec
Deborah Buszard
Macdonald College ofMcGill University, Ste-Anne-de-Bellevue y Quebec
Red Stele of strawberry, caused by
Phytophthora fragariae, is one of the most im-
portant strawberry diseases. One effective con-
trol is to breed red stele-resistant cultivars.
Evaluation of strawberry genotypes for suscep-
tibility to red stele has been based almost exclu-
sively on visual assessment of reddened stele in
the root. Visual disease assessments for red
stele, however, generally are subjective and
frequently are inconsistent. It has been shown
that resistant cultivars are not immune to infec-
tion, and relatively high numbers of oospores
may be observed in the root tissues of inoculated
resistant types as well as susceptible genotypes.
Therefore, while reddening of the stele in field-
grown plants may be used as a preliminary
diagnostic feature, visual symptoms should not
be used as the sole criterion to assess suscepti-
bility. Genotypes in which the pathogen sporu-
lates to a limited extent in the root may be
classified as resistant in genetic studies but it
does not imply that they are not infected.
In breeding trials where infection is evalu-
ated, no seedling or cultivar has been found to be
completely immune. Thus, the causal organism
probably is spread by infected, symptomless
roots. Planting stocks should be verified by
careful examination of randomly selected roots
for the presence of oospores. This relatively
simple technique might well be used prior to
planting to monitor the health of commercially
distributed daughter plants or certified stocks,
especially of resistant cultivars. Attention
should be paid to the term 'resistant,' which is
used widely in horticulture and plant pathology.
A cultivar resistant to Phytophthora fragariae
may not show any symptoms of red stele even
though it is infected by the fungus.
16
Fruit Notes, Spring, 1992
Sampling for Early-season Leafminer
Populations in Massachusetts in 1991
Kathleen P. Leahy and Ronald J. Prokopy
Department of Entomology, University of Massachusetts
Leafminers are among the most enigmatic of
all problem pests encountered in Northeastern
apple orchards. Leafminers did not become a
problem in Massachusetts until 1980. Since
then, however, they have appeared in many
orchards throughout the State, sometimes
briefly and sometimes for several years in a row.
The population dynamics and movement of
leafminers are not well understood, and there is
still some question as to the level and timing of
infestation that will cause harm, especially
when other pests or environmental stresses are
present. Additionally, in New England, we
experience the further complication of dealing
with not one, but two closely related leafminer
species: the spotted tentiform leafminer, which
is present in most North American apple grow-
ing regions, and the apple blotch leafminer,
which is confined mainly to eastern New York
and New England, although it does appear else-
where.
Although we did not have the resources to
investigate in a major way the myriad of factors
involved with leafminer management, we were
hopeful that the large number of blocks (12
second-level IPM test blocks and 12 paired
blocks managed by the growers) that were
sampled as part of the IPM Program in 1991
would give us an opportunity to look more
closely at seasonal patterns of leafminers. Since
all 12 growers refrained from using pre-bloom
leafminer controls, we were able to look at the
relationship between pre-bloom visual trap cap-
tures and first-generation mine counts. The
visual traps that we used were rectangular red
traps, which were either stapled at knee height
to the trunk on the south side of the tree ("trunk
traps") or hung at about head height in the
canopy as close to the trunk as possible ("canopy
traps"). We also compared the number of mines
on leaves of different ages and types (small and
large fruit cluster leaves and small and large
non-fruit-cluster leaves) to determine which
gave the best indication of the extent of
leafminer infestation.
Because of the unusually mild winter and
warm spring of 1990-91, leafminers apparently
had a very high survival rate and emerged in
large numbers anywhere that there had been
appreciable third-generation populations in
1990. The majority of growers in the second-
level IPM project needed to apply pesticide
against leafminer. All of these growers opted to
wait and treat the second-generation adults or
mines. The explosive growth of leafminer popu-
lations in the early part of the season may have
played some role in the difficulty we had in
interpreting the data.
We consistently found more mines on the
smaller (older) fruit cluster leaves than on any
other type of leaf (Figure 1), confirming that
these are the best leaves to check for determin-
ing whether or not a control is needed for
leafminer. (IPM recommendations since 1980
have been to examine the older fruit cluster
leaves in order to make control decisions.)
Leafminer adults generally begin to emerge at
half-inch green and continue flying through
pink, so that the leaves that are out at that time
are available to the females for laying eggs.
The New York State Simplified IPM (SIMP)
program uses a leafminer population assess-
ment of number of first-generation leafminer
eggs to determine whether or not a pre-bloom
treatment is needed. We attempted to make this
assessment, but were late in beginning our
monitoring for eggs, as we found virtually no
eggs at all.
Fruit Notes, Spring, 1992
17
200
CO
CD
cd 180
CD
i— <
© 160
to
& 140
CO
.1 12 °
a
<g 100
number
0) 00
o o
—
44
S 40
ex
3 20
Old Young Old Young
Fruit cluster leaves Non-fruit cluster leaves
Figure 1. The relationship of leaf age and type to the number of first-generation leaf mines.
We were unable to draw strong conclusions
from data on pre-bloom visual trap capture of
adults vs. mines per leaf (Figure 2), largely
because of high variability of mine numbers at
low trap capture levels. Without exception,
however, growers who had moderate or high
numbers of leafminers per trap (three per trap
by tight cluster and nine per trap by pink) were
over the threshold of 13 mines per leaf in the first
summer generation. Unfortunately, at low trap
capture numbers (average of zero to less than
nine per trap), the correlations did not hold up
well. In some cases, low captures on trunk and
canopy traps coincided with the expected low
number of mines, but in other cases they led to
mine numbers that were well over the thresh-
old. In a few cases, orchards which had no adults
caught on traps had potentially damaging levels
of first-generation mines. Some growers who
were not part of our second-level IPM program
also reported low trap captures followed by over-
the-threshold mine counts. In Figure 2, note
that for both trunk and canopy traps, the rela-
tionship between the numbers of captured
adults and the numbers of mines in leaves was
not significant.
Oddly enough, these data are opposite to the
trend found in 1990, when, possibly due to
unfavorable conditions during leafminer flight,
high trap captures were followed by a low num-
ber of first-generation mines. It is not clear why
the pattern in 1991 was unusual. One possible
18
Fruit Notes, Spring, 1992
explanation is that the weather during peak
female activity was warm and dry in 1991,
highly conducive to a maximum amount of
egglaying per female.
It is difficult to turn these data into a firm set
of recommendations. On the one hand, it is not
clear that a situation of explosive leafminer
growth from one generation to the next, such as
we had in 1991, will happen again soon. On the
other hand, the results from this year suggest
the need to take a more conservative approach
to early-season leafminer management. Some
growers may give up on the traps altogether;
however, it should be remembered that the
traps have given reliable results in most years
for most growers for nearly a decade. Also, the
effectiveness and non-disruptiveness of most of
our pesticides for leafminer control is greatest
when the pesticides are applied as early as
possible. This fact forces us to make a control
decision at a time when we are not sure of what
will happen with egglaying rate per leafminer
female, which is driven in large part by weather
conditions during the critical period. The ideal
situation would be to have a non-disruptive
material that could be used effectively against
first- or second-generation mines, allowing a
more confident reliance on thresholds. Unfortu-
nately, this is not likely to happen in the near
future; even Dimilin™, the most non-disruptive
material under testing for leafminer control, is
somewhat less effective when used against later
generations. And, we have no assurance that
Dimilin will be labelled for use against
leafminer on apples.
The approach taken in the 1992 March Mes-
sage is to reduce further the threshold for taking
action against leafminers to two per trap on the
trunk traps by tight cluster, four per trap on the
trunk traps by pink, and two per trap on the
canopy traps by pink. These are extremely
conservative thresholds but they should provide
a high degree of certainty that if the threshold is
not reached, leafminers will not reach damaging
levels.
Because those growers in our second-level
IPM program who had even moderate numbers
of leaf mines eventually did apply control mea-
sures, we were not able to follow leafminer
populations through the season and make any
correlation between leafminer pressure and
early fruit drop. Thus, we will leave our summer
action thresholds at the same level of 13 mines
per 100 leaves in the first generation, and 100
Adult Leafminers on Trunk Traps
and Resulting First-Generation Uinea
10 20 30 40 50 60 70 80 90
Adults per trap, cumulative through tight cluster
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Adult Leafminers on Canopy Traps
and Resulting First Generation Mines
I I I I I I I I
v /
-
* /
/
-
' /
V
-
' V
-
r
1 1 1 1 1 1 1 1
10 20 30 40 50 60 70 80 90
Adults per trap, cumulative through pink
Figure 2. The relationship between the capture of leafminer adults on rectangular red traps
and first-generation leaf mines.
Fruit Notes, Spring, 1992
19
mines per 100 leaves in the second generation,
as we have no data to indicate the need to revise
these thresholds either upward or downward.
In 1992, we hope to do more work on visual
trap captures as a predictor of leafminer prob-
lems. It should be possible again for second- level
IPM growers who use Dimilin to withhold treat-
ment until flight of second-generation adults,
thus allowing first-generation mines to be ex-
pressed, so we can have another opportunity to
examine the trap-capture and mines per leaf
relationship.
Predicting Infections of
Flyspeck on Apple
Daniel R. Cooley and James W. Gamble
Department of Plant Pathology, University of Massachusetts
One of the problems with managing flyspeck
and sooty blotch on apple is that we understand
so little about the two diseases. The disease
cycles have been described, but they are based
on very little knowledge. For example, the
flyspeck disease cycle description indicates that
ascospores are released at pink (Figure 1). This
timing indicates that control measures should
begin at pink. Historically, most growers have
applied fungicide for scab at this time and know-
ingly or not may have controlled flyspeck. The
sterol-inhibiting fungicides, however, do not
control flyspeck or sooty blotch. A half rate of
captan at pink is probably effective for one to two
Twig and fruit
tissue infected
Fruit Set to
Mid- July
Ascospores
are discharged
in rain
late Pink
Conidia produced in
lesions spread
during rain and
cause new infections
Mid June to
Harvest
Perithecia form
in orchard and
on wild hosts
Dormant
to Pink
Figure 1. The flyspeck life cycle.
weeks, but the question is, how important is it to
put a fungicide on at pink to control flyspeck and
sooty blotch? It appears that the application of
fungicide through bloom, and perhaps until well
after petal fall, to control summer diseases is not
that important.
In 1991, we studied flyspeck inoculum and
attempted to determine when it matured and
was able to infect apples. One major source of
inoculum is bramble canes, particularly black-
berry. We monitored the fungus on these canes
in the spring, in order to determine when sporu-
lation occurred. In 1991, ascospores were not
mature at pink. If fact, ascospores were not
mature until a week after petal-
fall. Unless there is another inocu-
lum source, no spores were avail-
able to cause flyspeck infections
before petal-fall. Rather than
spreading secondarily in min-
June, as indicated in Figure 1,
primary infections would have oc-
curred at this time. Therefore,
mid-June was the earliest time
that a fungicide should have been
directed at flyspeck.
We also looked at the condi-
tions which drive flyspeck devel-
opment. Based on a model devel-
oped by Turner Sutton and Eliza-
20
Fruit Notes, Spring, 1992
Table 1 . The number of hours of wetting which occurred before
flyspeck symptoms developed over four years in North Carolina.
Year
Hours of wetting until the
first flyspeck symptoms
Date of appearance of the
first flyspeck symptoms
1987
1988
1989
1990
260
250
288
279
June 14
July 23
June 22
July 16
beth Brown in North Carolina, we used wetness
and temperature to determine when the first
flyspeck symptoms would be visible. Beginning
ten days after petal fall, wetting periods and
heavy dews which exceeded three hours were
recorded. When the accumulated number of
hours of wetting reaches between 250 and 290,
the first symptoms should appear. Over four
years in North Carolina, this relationship
worked well (Table 1). It is hoped that this model
will have practical value in that an application
of Benlate™ or Topsin M™ just prior to symptom
expression should eradicate the symptoms. To
be conservative, such an application should be
made after about 230 hours of wetting.
Massachusetts and North Carolina are very
different in terms of flyspeck and sooty blotch
pressure. In general, the
season is two to four
weeks earlier in North
Carolina than in Massa-
chusetts, and pressure
from flyspeck and sooty
blotch is much greater.
It was not clear how well
the model would func-
tion in our climate. In
the Hudson Valley, in
the first year of running
the model, symptoms did
not appear until 370 hours of wetting. We were
pleasantly surprised in 1991. In our own obser-
vations at the University of Massachusetts Hor-
ticultural Research Center, we found symptoms
after 232 wetting hours, and within one day of
the predicted 250 hours (Figure 2 ). It is not clear
why there were major differences in the Hudson
Valley, or why we were slightly earlier than the
North Carolina observations. Possibilities in-
clude different criteria for deciding whether or
not a dew was a "heavy dew," placement of the
weather monitor relative to trees, and differ-
ences in the fungus. Weather monitor place-
ment could be critical to measuring wetness on
the fruit surface.
In 1992, we will continue this study and will
expand the monitoring and model work.
300 x
to
3
O
0>
250
.C 200 -■
CO
~ 150 H
to
100 -■
50 -■
o c
Predicted 1" flyspeck, July 13, 250 hrs.
■ Accumulated Wetting
□ Daily Wetting
First flyspeck observed
July 12, 232 hrs.
J.l.l.1 .l.i.i.i.i,t.
6 12 18 24 30 5 11 17 23 29 5 11
May May May May May June June June June June July July
Figure 2. Accumulated hours of wetting and the timing of the first
observations of flyspeck symptoms in Massachusetts in 1991.
Fruit Notes, Spring, 1992
21
Fruit Notes
University of Massachusetts
Department of Plant & Soil Sciences
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'68
Fruit Notes
Prepared by the Department of Plant & Soil Sciences.
ISSN 0427-6906
iSS.
University of Massachusetts Cooperative Extension System.
United States Department of Agriculture, and Massachusetts Counties Cooperating.
BIOLOGICAL
Editors: Wesley R. Autio and William J. Bramlage
SCIENCES LIBRARY
Volume 57, Number 3
SUMMER ISSUE, 1992
Table of Contents
Ringing and Scoring to Control Growth of
Apple Trees: Results from 1 99 1
Root Pruning. Part of the Second-level Apple
Integrated Pest Management Project
Susceptibility of Some Apple Cultivars to Fire Blight:
Implications for Massachusetts Growers
Peach Pests II: Insects and Mites
That Feed on Foliage and Wood
Using Fish Waste Hydrolysates as a Fertilizer
for Apples and Blueberries
/T
Fruit Notes
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Fruit Notes
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Ringing and Scoring to Control Growth
of Apple Trees: Results from 1991
Wesley R. Autio and Duane W. Greene
Department of Plant & Soil Sciences, University of Massachusetts
Regulation of vegetative growth is one of the
most important orchard practices. Tradition-
ally, pruning has been used by apple growers as
the sole means of regulating growth. Pruning,
however, results in a localized stimulation of
growth near the cuts, which ultimately reduces
fruiting potential. Frequently, a "vicious cycle"
can begin, where pruning is used to remove the
undesirable growth that resulted from a previ-
ous cut, and the tree's response is to produce
more undesirable growth which must be cut out
during the next dormant season. Many trees
presently in production are caught in this cycle
and thus are not fruiting to their full potential.
Why Control Growth?
A need to maintain a tree in a given space is
the most common reason for using growth con-
trolling techniques. Often, tree spread must be
controlled when soil conditions result in greater
than anticipated vigor, the wrong rootstock was
chosen for a particular cultivar, the scion vigor
was not integrated into the spacing decision, or
simply the trees were planted closer than they
should have been. In almost all situations, tree
height must be controlled to increase light pen-
etration to the lower portions of the tree canopy
and to reduce the need for tall ladders during
harvest. Pruning can provide both spread and
height control; however, two cultural tech-
niques are available which can control growth
and avoid the negative effects of pruning: scor-
ing and ringing.
The Practices of Scoring
and Ringing
Scoring, very simply, is the process of mak-
ing a single cut with a knife (a linoleum knife
works very well) completely around the trunk of
the tree usually when terminal growth is be-
tween 4 and 6 inches long(approximately 7 to 10
days after petal fall). Ringing differs from scor-
ing only in the width of the cut. With scoring, no
bark is removed, so the cut heals relatively
quickly; however, with ringing a portion of bark
is removed, and depending on the width of that
portion, healing takes significantly longer. Gen-
erally, a pruning saw is used to make the scoring
cut. A "Turbo-cut" saw will make a cut approxi-
mately 1/16 inch wide.
Basal Scoring and Ringing, 1991
For whole-tree growth control, scoring and
ringing cuts are made between the soil and the
lowest scaffold branch. Table 1 shows the result
obtained in a study conducted at the University
of Massachusetts Horticultural Research Cen-
ter (Belchertown, MA) in 1991. In this experi-
ment, seven blocks of mature Gardiner Deli-
cious/MM.106 trees were selected, and one tree
in each block was either ringed, scored, or not
treated (control). Scoring and ringing were
performed on May 16, when terminal growth
was between five and six inches. Four- fruit
samples were taken throughout the harvest
season, and internal ethylene was used to deter-
mine when ripening began on the tree. A single
harvest of 30 fruit was made from each tree on
September 30 and weighed, and 10 fruit were
used to measure the percent soluble solids (sug-
ars) in a juice sample. Natural fruit drop from
each tree was assessed periodically from Sep-
tember 17 to October 16.
Ringing and scoring caused a similar level of
growth reduction, resulting in approximately
half of the trunk growth experienced by the
controls (Table 1). Fruit size was unaffected by
Fruit Notes, Summer, 1992
Table 1. Effects in 1991 of basal scoring and ringing on trunk growth and
fruit characteristics of mature Gardiner Delicious/MM.106 trees. Trees
were scored or ringed approximately 18 inches from the soil surface on
May 16, 1991, when terminal growth ranged from five to six inches.*
Treatment
Increase in trunk Fruit
cross-sectional size
area (in 2 ) (oz)
Date of the Soluble
beginning solids
of ripening (%)
Control
Score
Ring
3.15 a 6.0 a
1.35 b 6.4 a
1.76 b 6.5 a
10-2 a 10.4 b
9-25 b 11.9 a
9-24 b 11.8 a
Means within columns not followed by the
different at odds of 19:1.
same letter are significantly
80
Control
9/17
9/23
9/29
10/5
10/11
10/17
Figure 1. Effects in 1991 of basal scoring and ringing on fruit drop from Gardiner
Delicious/MM.106 trees.
Fruit Notes, Summer, 1992
ringing and scoring, but ripening was advanced
by approximately one week (Table 1). Drop was
also advanced by approximately one week (Fig-
ure 1).
Clearly, these treatments successfully re-
duced growth of the trees in this study. Care
must be taken, however, to select appropriate
trees for these whole-tree treatments. Ringing
or scoring of a weak tree may overly devigorate
the tree, an effect which may last for several
years. Although ringing and scoring acted simi-
larly in this experiment, ringing often is much
more dramatic in its response. Ringing should
be done only in situations when you need a
dramatic reduction in growth.
An additional caution regarding ringing and
scoring is their effect on ripening. Advanced
ripening resulted in advanced drop. Ripening
and drop must be monitored in trees that have
been scored or ringed to avoid excessive losses in
quality or to the ground.
Top Scoring, 1991
Because of the need to control tree height in
almost all cases, significant pruning is often
used in the top of the tree. This procedure can
cause the tree to grow out of balance, with the
top being vigorous and the lower scaffolds hav-
ing low vigor. Figure 2 shows this situation in a
mature Mclntosh/M.9 tree.
As a potential means of controlling top vigor
Figure 2. Mclntosh/M.9 tree showing undesirable growth in the top of
the tree as the result excessive pruning at the top.
Fruit Notes, Summer, 1992
Figure 3. The effects of top scoring on May 13, 1991 on
mature Cortland/M.7 trees (a. without top-scoring; b.
scored approximately four feet from the top of the two-
year-old portion of the central leader). Photographs were
taken in March, 1992.
Fruit Notes, Summer, 1992
Table 2. Effects in 1991 of top scoring on the terminal growth
near the top of mature Cortland/M.7 trees. Trees were scored
approximately four feet from the top of the two-year-old
portion of the central leader on May 13, 1991. Terminal
growth ranged from three to four inches at the time of scoring.*
Average terminal characteristics
Treatment
Weight Length
(oz) (in)
Diameter
(in)
Control
Score
1.26 a 33.4 a
0.50 b 21.1b
0.32 a
0.22 b
Means within columns not followed by the same letter are
significantly different at odds of 19:1.
we conducted two top-scoring studies in 1991.
The first was conducted at Rice Fruit Farm in
Wilbraham, MA and utilized mature Cortland/
M.7 trees. These trees previously had been
pruned vigorously at the top on an annual basis.
Six pairs of trees were chosen, and one tree in
each pair was scored approximately four feet
down from the top of the two-year-old wood of
the central leader on May 13. Terminal growth
ranged from three to four inches.
Table 2 shows the effect on the terminal
growth above the score. Scoring resulted in
significantly reduced terminal weight, length,
and diameter, but it also significantly reduced
the number shoots arising in the top of the tree
(compare Figures 3a and 3b).
The second study was conducted at Tougas
Farms in Northborough, MA, using Pioneer
Mac/Mark in their third leaf. One tree in each of
six blocks was scored just below the top tier of
branches (approximately five feet above
ground). No data are presented, but this treat-
ment resulted in a desirable reduction in growth
in the top of the tree , along wi th the development
of flower buds in that region.
Scoring in the top of the tree is a simple, but
very effective way to break the grow-and-cut
cycle started by excessive pruning. It could be
used very effectively after a dormant season
when the height of a tree was dramatically
reduced or as a regular treatment to keep the top
in control. We believe that it will be a very
important technique for control of the leader in
high-density, slender-spindle trees. Research
begun in 1 992 is assessing dormant-season scor-
ing and ringing as a potential technique for top
control that could be completed when the trees
are pruned.
Acknowledgements
We are grateful for the participation and
support of Wayne Rice and Maurice Tougas.
Fruit Notes, Summer, 1992
Root Pruning, Part of the Second-level
Apple Integrated Pest Management
Project
Wesley R. Autio and Duane W. Greene
Department of Plant & Soil Sciences, University of Massachusetts
James W. Gamble
Department of Plant Pathology, University of Massachusetts
Margaret M. Christie and Kathleen P. Leahy
Department of Entomology, University of Massachusetts
In the previous article we discussed the
growth controlling techniques of scoring and
ringing. A third cultural technique, root prun-
ing, has been studied extensively by Dr. James
Schupp (University of Maine) and Dr. David
Ferree (Ohio State University). In 1991, we
conducted root pruning experiments as part of
the Second-level Apple Integrated Pest Man-
agement Project.
Root pruning was included in the Second-
level IPM Project because of a number of re-
ported positive effects. Specifically, root prun-
ing reduces vegetative growth. The advantage
of this effect to the apple grower is twofold: less
time is required to prune the trees, and air
movement through the tree canopies is en-
hanced. The enhanced air movement should
result in reductions in summer-disease inci-
dence by reducing drying time and relative
humidity. Additionally, pesticide penetration
into the canopy should be improved. The second
reported effect of root pruning is a delay in
natural fruit drop. If this effect is consistent,
then a larger portion of the crop on the tree will
be able to be harvested, significantly reducing
economic losses. A second benefit of this delayed
abscision relates directly to pest management.
Reduced numbers of fruit on the ground de-
creases the effort required to remove those fruit
from the orchard floor, a requirement of second-
level IPM for apple maggot control.
Root pruning is a dramatic treatment, cut-
ting off more than half of the feeder roots within
12 inches of the soil surface. It is not a treatment
to be taken lightly, since it has the potential for
reducing growth severely. If trees are overly
stunted, then productivity will decline and fruit
size will be small. To ere on the side of caution,
we decided to study root pruning only on those
Second-level IPM sites most severely needing
growth control. We wanted to study a number
of effects and the consistency of response in
order to determine whether or not root pruning
should be included in our Second-level IPM
Plan.
The Root Pruning Procedure
Root pruning is accomplished with a sharp-
ened subsoiling blade attached to a tool bar on
the tractor. The blade is set so that it penetrates
the soil to a depth of 12 inches. The blade is
passed by both sides of the tree at a distance of
36 inches from the trunk.
For our study, three of the six full second-
level treatment sites were chosen. These sites
were Fay Mountain Farm (Charlton), Rice Fruit
Farm (Wilbraham), and the University of Mas-
Fruit Notes, Summer, 1992
sachusetts Horticultural Research Center
(Belchertown). Each of these sites clearly in-
cluded overly vigorous trees. Trees used at Fay
Mountain Farm were mature Mcintosh/
MM. 106, those at Rice Fruit Farm were mature
Cortland/M.7, and trees at the Horticultural
Research Center were mature Gardiner Deli-
cious/MM.106. At Fay Mountain Farm and Rice
Fruit Farm, trees were partitioned into four
blocks. Approximately half of each block was
root pruned on May 13, 1991 (4 to 8 days after
petal fall) with a "Phil Brown Welding" root
pruner. Both sides of the tree row were root
pruned. Trees at the Horticultural Research
Center were pruned similarly, but only a single
tree in each of seven blocks was pruned. Fruit
drop was assessed periodically throughout the
harvest season, and the length, diameter, and
weight of terminal growth was measured during
the winter.
1991 Results
Table 1 shows the effects of root pruning on
shoot growth. Shoot growth clearly was reduced
at Fay Mountain Farm and Rice Fruit Farm;
however, no effect was measured at the Horti-
cultural Research Center. It is puzzling why
root pruning significantly reduced growth at
two locations and not the other. One possible
explanation may be the soil conditions at the
Horticultural Research Center (the site is rela-
tively wet), or the discrepancy could relate to the
cultivars, that is, Delicious at the Horticultural
Research Center and Cortland and Mcintosh at
the other sites. We have repeated the experi-
ment at the Horticultural Research Center this
year in the same block, but using Mcintosh trees
rather than Delicious trees.
Figures l,2,and3showfruitdropduringthe
harvest season at Rice Fruit Farm, Fay Moun-
tain Farm, and the Horticultural Research Cen-
ter, respectively. Clearly, root pruning resulted
in significant reductions in drop at Rice Fruit
Farm and Fay Mountain Farm; however, as
with growth, there was no effect on drop at the
Horticultural Research Center (possibly for the
same reasons as mentioned above).
Table 1. The effect of root pruning at three locations in
May on shoot
growth.*
Location
Treatment
Averagi
i terminal characteristics
Weight
(oz)
Length
(in)
Diameter
(in)
Fay Mountain Farm
Rice Fruit Farm
Hort. Res. Center
Control
Root pruned
Control
Root pruned
Control
Root pruned
0.15 a
0.08 b
0.20 a
0.14 b
0.17 a
0.12 a
10.4 a
7.8 b
11.7 a
9.3 b
11.4 a
9.6 a
0.19 a
0.16 b
0.24 a
0.21 a
0.17 a
0.15 a
* Within location and column, means
significantly different at odds of 19:1.
not
followed
by
the same
letter are
Fruit Notes, Summer, 1992
70
60
Mclntosh/MM.106
8/20
Root pruned
i i i i i i i i i
8/27
9/3
9/10
9/17
9/24
Figure 1. The effect of root pruning on May 13, 1991 on drop
of fruit from mature Mclntosh/MM. 106 trees at Fay Mountain
Farm in Charlton, MA.
60
^^
Cortland/M.7 f
as so
c
o
Q.
Control /
2 40
u
o
^30
a.
o
■D
<i> 20
a /
/ Root pruned
3
^^ ^^^ b
E 10
3
o
^^ a ^^^^^
j — i^U — r~T i i i i i i i i i i i i i i i i
U «
8/20 8/27 9/3 9/10 9/17
Figure 2. The effect of root pruning on May 13, 1991 on drop
of fruit from mature Cortland/M.7 trees at Rice Fruit Farm in
Wilbraham, MA.
8
Fruit Notes, Summer, 1992
60
5 50
c
o
a.
o 40
o
2.30
Q.
O
w
■D
o> 20
>
'J
a
E
o
10
Delicious/MM.106
9/16
Control
I I I I I I I I I I I I I I I l_l L
9/22
9/28
10/4
10/10
10/16
Figure 3. The effect of root pruning on May 15, 1991 on drop
of fruit from mature Gardiner Delicious/MM.106 trees at the
Horticultural Research Center in Belchertown, MA.
Root pruning can reduce growth and reduce
drop as seen in two of three sites in 1991;
however, it is a drastic treatment. It should only
be used in those situations where significant
growth control is required, that is, where trees
are overly vigorous. Effects on drop should be
seen only as added benefits rather than a reason
for root pruning.
Acknowledgements
The study reported here was part of a larger
project that was funded by the Massachusetts
Society for Promoting Agriculture, the USDA
Northeast Regional IPM Competitive Grants
Program, and the Massachusetts Fruit Grow-
ers' Association. We gratefully acknowledge
this funding. We are also grateful for the partici-
pation and support of Dick Gilmore, Greg
Gilmore, Wayne Rice, and Jesse Rice.
Fruit Notes, Summer, 1992
Susceptibility of Some Apple
Cultivars to Fire Blight: Implications
for Massachusetts Growers
Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Parts of this article were excerpted from an
article to be published in Plant Disease by T. M.
Thomas and A. L. Jones of Michigan State
University, who generously agreed to share the
information so that it may be used in a timely
way. In 1991, there was an unusually severe
epidemic of fire blight on apples in Michigan. In
trying to make the best out of a disastrous
situation, Michigan researchers evaluated 84
apple cultivars being grown at the Southwest
Michigan Research and Extension Center in
Benton Harbor. They concluded the evaluation
with a warning: many of the new cultivars being
planted are particularly susceptible to fire
blight. In addition, more trees are being planted
on dwarf rootstocks, including M.26, that are
highly susceptible to fire blight. Finally, strep-
tomycin-resistant strains of the bacteria that
cause fire blight (Erwinia amylovora)have been
foundin many apple production areas, including
Michigan. Without streptomycin, susceptible
cultivars are in serious danger from fire blight in
Michigan.
While streptomycin-resistant Erwinia
amylovora have never been found in Massachu-
setts, the bacteria could easily mutate or be
transported here. In some years, isolated Mas-
sachusetts orchards have had serious problems
with fire blight. Still, fire blight pressure in our
region has never reached epidemic proportions.
Should Massachusetts growers be con-
cerned with fire blight susceptibility when
planting apple cultivars? Cultivar selection
usually is driven by market forces rather than
disease susceptibility; however, we generally
have methods, chemical or cultural, which can
manage serious diseases. How would the situa-
tion change, however, if streptomycin were not
effective against fire blight?
New York rated fire blight susceptibility of
several cultivars in the early 1970's, and these
ratings correlated well with the ratings ob-
tained in Michigan in 1991. Older, well-known
cultivars generally were rated the same in each
test. Many new cultivars, however, such as
Gala, Braeburn, and Fuji, not grown in 1974
were present only in the Michigan test. Right
now, most of our trees in New England are
Mcintosh. On a five-step scale (l=very resis-
tant; 2=moderately resistant; 3=intermediate;
4=moderately susceptible; 5=very susceptible),
Mcintosh is rated intermediate. Interestingly,
Marshall Mcintosh was not more susceptible
than Macspur, Pioneer Mac, or Red Max in the
Michigan test.
According to these tests, our major cultivar
is not particularly sensitive to fire blight. From
experience, we know that in some situations,
natural occurrence of fire blight in Massachu-
setts can damage Mcintosh trees significantly.
We could conclude that fire blight pressure is
variable in the state, and on some occasions in a
few orchards it can be severe enough to damage
Mcintosh. In the Michigan test, other cultivars
such as Delicious and Liberty were more fire-
blight resistant than Mcintosh. Empire and
Mcintosh were both rated "intermediate".
Golden Delicious, Jonagold, Mutsu, and most
Gala strains were somewhat more susceptible
than Mcintosh. Idared, Braeburn, and Fuji
strains were much more susceptible than Mcin-
tosh. (Table 1). The ratings are not terribly
surprising, if we consider that fire blight is not
10
Fruit Notes, Summer, 1992
Table 1. Ratings of selected cultivars and strains
made after the Michigan fire blight epidemic, 1991.
Cultivars are listed in order, from most resistant to
most susceptible, using a 5 point scale developed at
Geneva, NY: 1= very resistant; 2=moderately resis-
tant; 3 intermediate; 4=moderately susceptible;
5=very susceptible.
Cultivar
Rating
Red Chief Delicious (Campbell)
Liberty
Red Max
2
2
3
Empire
Marshall Mcintosh
3
3
Freedom
3
Prima
3
Scarlet Gala
3
Pioneer Mac
3
Akane
3
Red Fuji
Stark Gala
4
4
Mutsu
4
RedCort
4
Golden Delicious
4
Imperial Gala
Fulford Gala
4
4
Royal Gala
Red Fuji #4
Jonagold
Red Fuji Nagano
Spigold
Fuji
Braeburn
4
4
4
5
5
5
5
Idared
5
yet present in New Zealand or Japan, home of
Gala, Braeburn, and Fuji.
New England probably has somewhat less
fire blight pressure than Michigan or New York,
and may not have a large population of strepto-
mycin-resistant Erwinia amylovora. While the
situation in our region should not discourage
people from planting limited amounts of the new
cultivars, extensive plantings may present
some significant long-term risks from fire blight.
Fruit Notes, Summer, 1992
11
Peach Pests II: Insects and Mites
That Feed on Foliage and Wood
Karen I. Hauschild
University of Massachusetts Cooperative Extension System
In "Peach Pests I" [Fruit Notes 57(2):14-16],
I discussed insects that feed on peach fruit. In
this article, I will focus on two groups of pests-
insects and mites that feed on peach foliage and
insects that burrow into and feed on peach
shoots or wood.
Leaf-feeding insects (primarily aphids) and
mites only are occasional pests in peach or-
chards; however, they may cause serious injury
in isolated trees or blocks. Aphids may need to be
controlled when populations become high
enough to cause leaf curl or when disease trans-
mission is a consideration. Mites, especially in
hot, dry weather, can build up quickly and
reduce the photosynthetic ability of foliage.
Three shoot- and wood-feeding insects cause
problems in peach orchards. First generation
Oriental fruit moth larvae bore into and feed on
young peach shoots causing their death. Larvae
of the peach tree borer and the lesser peach tree
borer tunnel into peach wood, resulting in dam-
age that often is invaded by canker diseases.
Additionally, heavy borer infestations can
weaken limbs or trunks and lead to breakage
and tree loss.
Below is a brief description of each of these
pests, the damage each causes, and basic infor-
mation on non-chemical control.
Green Peach Aphid
The most prevalent aphid found on peaches
is the green peach aphid (Myzus persicae). This
species occurs worldwide and has a diverse host
range. Green peach aphids are very small, about
1/12 inch long. Wingless adults range in color
from pinkish-red in early spring and fall to
yellowish-green with a darker head during the
summer. Winged adults have a darker head and
thorax with a blotched yellowish abdomen.
Young aphids (nymphs) resemble winged adults
but are smaller.
In New England, green peach aphids over-
winter as shiny, black oval-shaped eggs on twigs
or bark. These eggs hatch about the same time
as leaves appear on peach trees. Aphids have
sucking mouth parts, and first generation
nymphs feed on unfolding leaves or flower buds.
These nymphs develop into wingless females
that bear live young, resulting in rapid build-up
of populations. Heavy feeding by nymphs and
adults can result in leaf curl, stunted growth,
and reduced fruit set. Several generations of
green peach aphids occur in a season. In late
spring, however, adults grow wings and move to
other crops, returning to peaches in late fall.
Nymphs produced in the fall mature, mate, and
lay overwintering eggs.
If green peach aphid populations are high,
oil should be applied the following spring to
prevent hatching of overwintering eggs. In gen-
eral, insecticides applied for controlling other
peach pests will control the green peach aphid.
Two-spotted Spider Mite
The two spotted spider mite (Tetrannychus
urticae) feeds on ground cover plants in peach
orchards, moving to trees when ground cover
plants have dried due to hot weather or when the
ground cover is tilled or treated with herbicide.
The two-spotted spider mite also can become
troublesome when its predator, Amblyseius
fallacis, is killed by non-selective pesticides.
Mites are closely related to insects, but have
four pairs of legs rather than three pairs. They
have sucking mouthparts. Adult females are
yellow to green with two dark patches on their
abdomens. They are very tiny, about 1/60 of an
inch long, and often can only be detected by the
12
Fruit Notes, Summer, 1992
damage they cause or by seeing their movement
on leaf surfaces. Female mites overwinter in the
orchard understory or under tree bark. Eggs laid
in early May hatch in 5 to 8 days. Larvae (young
mites) are pale to dark green with two dark
spots. One generation can be completed in as few
as 21 days, resulting in up to nine generations
per growing season. Mite damage appears as
leaf stippling or off-color foliage.
Under optimal conditions predator mites
can control two-spotted mites; however, these
predators are killed by non-selective pesticides
such as the synthetic pyrethroids. Mite levels
should be monitored, especially in trees which
have had infestations in past years. Hot, dry
weather favors mite build-up. Check with your
local county agent or fruit specialist for updated
information on mite treatment threshold levels.
One predator mite for every 5 to 7 pest mites
usually results in biological control.
Oriental Fruit Moth
As mentioned in "Peach Pest I," first genera-
tion larvae of the Oriental fruit moth burrow
into rapidly growing peach terminals. Larvae
enter near a leaf axil and tunnel down the shoot
core for up to six inches, killing the affected
terminal. As terminal growth hardens, larvae
move to peach fruit as a food source. (Refer to
"Peach Pests I" for additional information on
Oriental fruit moth.)
Peach Tree Borer
The peach tree borer (Synanthedon exitosa)
and the lesser peach tree borer (Synanthedon
pictipes) are the most serious pest of peach wood.
Larval tunneling by both species weakens trees
and serves as entry sites for canker diseases.
Adult peach tree borers are clearwing
moths. Females are dark blue with a broad
orange band encircling their abdomens. Their
front wings are blue, while their hindwings are
clear. Adult males are lighter blue with several
yellow stripes around their abdomens and with
both pairs of wings clear. Larvae are cream to
light yellow with brown heads and are 1 to 1.25
inches long when fully grown. Larvae have three
pairs of true legs and four pairs of fleshy "pro-
legs."
Peach tree boers overwinter as larvae within
their burrows. Warm weather (temperatures
greater than 50°F) prompts larvae to begin
feeding in the spring. Larvae leave their bur-
rows to construct their pupal cocoons. These
pupae complete their transformation in about
four weeks. Cocoons can be found in an upright
position just beneath the soil near the tree
trunk. In our area, adults emerge from early
July into September. Adults mate soon after
emerging and egg-laying begins almost immedi-
ately after mating. Each female lays an average
of 400 reddish-brown eggs under loose bark,
near wounds, in cracks, or on other rough areas
on tree trunks. These eggs hatch in about 10
days, and the larvae immediately tunnel into
the bark on the lower tree trunk, feeding on the
cambium layer. These larvae then remain in the
tree until the following spring.
Adult male emergence and peak activity can
be monitored with pheromone traps. Signs of
larval activity include sap exuding from tree
trunks or build-up of frass (insect excrement and
wood particles) at the base of the tree. Non-
chemical controls that have been recommended
in the past included using a stiff wire to kill
larvae in their tunnels and mounding moth balls
at the base of trees. These measures, however,
are often not practical in a commercial peach
orchard. Mating disruption, baiting an orchard
with synthetic pheromone, may soon be avail-
able as a practical alternative to chemical con-
trol.
Lesser Peach Tree Borer
Adult lesser peach tree borers are very simi-
lar in appearance to male peach tree borer
adults. They, too, are blue-black clear-winged
moths with yellow bands on their abdomens.
Larvae are light tan to cream-colored with dark
heads and are about one inch long when mature.
Lesser peach tree borers overwinter as lar-
vae in galleries beneath bark. Larval develop-
ment is completed in the spring after which the
larvae burrow into the outer bark surface to
pupate. Adult emergence begins in late May and
Fruit Notes, Summer, 1992
13
continues until September, with peak emer-
gence usually occurring from mid-June to mid-
July. Shortly after they emerge adult female
lesser peach tree boers mate and lay reddish-
brown eggs in cracks, crevices, crotches, around
wounds, or in any injured area of the tree above
ground. Usually eggs are laid within three to
four feet of ground level. Eggs hatch in about ten
days. Larvae feed on tender, young bark and
then move into the cambium layers. Larvae
remain in the tree until the following spring.
Adult lesser peach tree borers' activity can
be monitored with pheromone traps. Chemical
control, if needed, should be applied within three
to four weeks after the first male moth capture.
Gummosis, sap bleeding from entry wounds,
indicates presence of larvae.
Since lesser peach tree borer has difficulty
becoming established in healthy wood, main-
taining tree vigor can help prevent infestations.
Proper pruning techniques, white washing to
prevent winter injury, and care when using
equipment around trees will help protect
against lesser peach tree borer attack.
For additional information on any of these
pests, please refer to:
Prokopy, R.J., P.J.Powers, D.R. Cooley,
and J.W. Gamble. 1991. Peaches, Pears,
Plums-Pest Control Guide for Commer-
cial Growers in Southern New England.
University of Massachusetts Coopera-
tive Extension System Circular C-159 R
1991-2.
Myers.S.C. (ed.) 1989. Peach Production
Handbook. Univ. of Georgia Cooperative
Extension Service.
"Peach Pests III" (appearing in the next
issue of Fruit Notes) will focus on peach diseases.
14
Fruit Notes, Summer, 1992
Using Fish Waste Hydrolysates as a
Fertilizer for Apples and Blueberries
Sarah A. Weis and William J. Bramlage
Department of Plant and Soil Sciences, University of Massachusetts
New England processing plants generate up
to 100 million pounds of fish waste per year.
Much of this material is disposed of at sea and in
landfills, practices that can be both offensive
and wasteful. Procedures have been developed
to liquefy fish waste as stable acid hydrolysates
containing specified percentages of nitrogen (N),
and other elements. These hydrolysates have
been tested as fertilizer sources for greenhouse
crops, turf grasses, and cranberry bogs, with
encouraging results.
Nitrogen is the primary fertilizer element
used for fruit crops. The availability of fish
waste hydrolysates for use on fruit crops offers
an alternative to conventional fertilizer sources
that also may be beneficial to the fishing indus-
try, waste disposal problems, and concerns
about environmental contamination. Further-
more, its use might be especially appealing to
the increasing numbers of people interested in
growing crops as organically as possible, since
the hydrolysates provide N in an organic form.
In cooperation with the University of Massa-
chusetts Gloucester Marine Station, we under-
took a program to test the use of fish hydroly-
sates as a fertilizer source for young apple trees
in 1990 and 1991,andalsoforhighbushblueber-
ries in 1991.
Experiment 1
We selected a block of one-year-old Early
Red One Delicious apple trees on Mark root-
stock, planted at the University of Massachu-
setts Horticultural Research Center (HRC) in
Belchertown. These trees were being grown
using standard horticultural practices except
for the fertilizer treatments described below.
Fish hydrolysates used as fertilizer were
prepared by personnel at the University of Mas-
sachusetts Marine Station, Gloucester. Each
type of hydrolysate was prepared to contain
2.5% N, 5% P, and 2.5% K, and they also con-
tained small amounts of other mineral nutri-
ents.
Treatments were as follows:
1. Ammonium nitrate, 0.1 lb N per tree.
2. Herring hydrolysate, 2 qt per tree.
3. Cod hydrolysate, 2 qt per tree.
Treatments were replicated 6 times, with
individual trees as experimental units. Each
treatment applied the same amount of N per
tree, but treatment 1 did not provide the P and
K that was contained in the fish hydrolysates.
These treatments were applied in both 1990 and
1991, and fertilizers were applied on May 29,
1990 and May 7, 1991. Tree growth was mea-
sured by recording trunk diameter at an indi-
cated height in May and September, 1990, and
October, 1991. Leaves were taken for mineral
analyses in September, 1990, and in July, 1991.
In October, 1991, the limited numbers of fruit on
each tree were harvested. They were stored for
6 months at 32°F plus 1 week at 70°F, and
occurrences of bitter pit, senescent breakdown,
and rot were recorded.
Concentrations of N, P, and K in the leaves
are shown in Table 1. In 1990 the only difference
was in K, with the fish hydrolysates (which
contained 2.5% K) producing higher leaf K con-
centrations. In 1991, there was higher leaf N
when cod rather than herring hydrolysate was
used, and higher leaf P when herring rather
than cod was used. Since, however, both hydro-
lysates were made up to provide the same
amounts of N, P, and K, these differences have
no apparent association with treatment. Leaves
were also measured for calcium, magnesium,
Fruit Notes, Summer, 1992
15
Table 1. Comparisons of fish hydrolysates and
apple trees. Mineral analyses of leaves.
inorganic nitrogen as fertil
zer
sources
for Delicious
Element
Material
Statistical
significance 1
NH 4 N0 3
Cod
hydrol.
Herring Among
hydrol. treatments
NH<N0 3
vs. fish
Cod vs.
herring
1990
Nitrogen
1.85%
1.76%
1.80%
ns
—
...
Potassium
1.32%
1.50%
1.60%
*
**
ns
Phosphorus
0.17%
0.17%
0.18%
1991
ns
—
—
Nitrogen
2.28%
2.39%
2.10%
**
ns
**
Potassium
1.57%
1.41%
1.50%
ns
...
...
Phosphorus
0.19%
0.20%
0.29%
**
ns
**
'Significance
: **, *, and ns =
odds of 99:1, 19:1,
or not significant, respectively.
Table 2. Comparisons
of fish hydrolysates and inorganic nitrogen as fertilizer
sources for
Delicious apple trees.
Tree growth
and fruit quality.
Material
Significance
Measure
NH 4 N0 3
Cod hydrol. Herring hydrol.
1990
Trunk growth
3.4
3.4 3.2
ns
(cm increase)
Terminal growth
48
46 50
ns
(cm/limb)
1991
Trunk growth
4.5
3.5 4.2
ns
(cm increase)
Terminal growth
41
42 41
ns
(cm/limb)
1991
Total fruit/tree
23
24 20
ns
Bitter pit (%)
20
17 14
ns
Senescent
10
12 11
ns
breakdown (%)
Rot (%)
10
12 11
ns
1
16
Fruit Notes, Summer, 1992
boron, manganese, copper, and zinc concentra-
tions, and there were no differences among
treatments except for a slightly higher zinc level
in leaves fertilized with cod hydrolysate than
with herring hydrolysate or ammonium nitrate.
Tree growth measurements are shown in
Table 2. Neither increase in trunk circumfer-
ence nor amount of terminal growth was influ-
enced in either year by fertilizer source. Also
shown in Table 2 are total numbers of fruit
harvested from each tree, and the incidences of
disorders in the fruit after storage in 1991.
There was no effect of fertilizer source on either
total fruit per tree or development of disorders
after storage.
Experiment 2
A block of scab-resistant apple cultivars
planted in 1988 at the HRC was chosen. An
experiment was established applying 4 treat-
ments with 6 replications, 3 replications using
Liberty trees and 3 replications using Redfree
trees, both on M.26 rootstocks.
Treatments were as follows:
1. Ammonium nitrate, 0.9 lb per tree, plus 2.5
lb of 0-24-0 fertilizer and 1 lb of 0-0-61
fertilizer.
2. Cod hydrolysate (6% N), at 5.2 lb per tree.
3. Herring hydrolysate (5% N), at 6.3 lb per
tree.
4. Shrimp and cod (shrimp) hydrolysate (5%
N), at 6.3 lb per tree.
Hydrolysates were made up to contain twice
as much P as N, and an equal amount of K as N,
and treatments were designed to apply equal
amounts of N, P, and K to all trees. Treatments
were applied on May 7 , 1 99 1 . Leaves were taken
in July, 1991 for mineral analyses. No growth
measurements were made, but both trees and
fruit were examined periodically.
Leaf mineral analyses of N, P, and K are
presented in Table 3. Magnesium, calcium,
manganese, boron, zinc, and copper also were
analyzed but data are not presented. The only
differences recorded were in leaf K and manga-
nese. All hydrolysates were made up to contain
the same amount of K as was applied with the
ammonium nitrate, yet all hydrolysates pro-
duced lower K concentrations than did the inor-
ganic fertilizer treatment. The hydrolysates all
contained some manganese, which was not sup-
plied with the inorganic fertilizer treatment.
Yet, the hydrolysates all produced lower leaf
manganese concentrations. Since neither the K
nor the manganese difference is reconcilable
with treatment, and neither response occurred
in Experiment 1, it is likely that these differ-
ences are spurious and not reproducible. Also,
there was no evident difference in tree growth or
fruit quality among the trees in this experiment.
Experiment 3 and 4
Two experiments were established in high-
bush blueberry plantings in 1991. Experiment
3 was established in a mature planting at the
HRC. Four treatments were applied:
Table 3. Comparisons of fish hydrolysates and
resistant Liberty and Redfree apple trees grown in
inorganic nitrogen as fertilizer sources for scab-
a LISA management system. Leaf analyses. 1991.
Element
Material
Si
gnificance 2
NH 4 NO
Cod
5 hydrol.
Herring
hydrol.
Shrimp
hydrol.
Among
treatments
NH 4 N0 3
vs. fish
Among
hydrol.
Nitrogen
Potassium
Phosphorus
2.36%
1.03%
0.15%
2.35%
0.86%
0.16%
2.34%
0.86%
0.16%
2.28%
0.87%
0.16%
ns
*
ns
**
ns
'Significance:
**, *, ns =
odds of 99:1,
19:1, or not s
>ignificant, respectively.
Fruit Notes, Summer, 1992
17
1. Eight oz of ammonium sulfate + 13 oz of 0-
24-0 fertilizer + 3 oz of 0-0-61 fertilizer per
bush.
2. Cod hydrolysate (3% N), 3.3 lb per bush.
3. Herring hydrolysate (3% N), 3.3 lb per bush.
4. Shrimp and cod (shrimp) hydrolysate (3%
N), 3.3 lb per bush.
Hydrolysates were made up to contain twice
as much P as N, and equal amounts of K and N,
so all treatments were designed to apply 0.1 lb
of N, 0.2 lb of P, and 0.1 lb of K per bush.
Treatments were applied on May 7, 1991.
Each treatment was replicated 7 times, with
each replicate being a separate cultivar:
Earliblue, Collins, Blueray, Bluecrop, Herbert,
Coville, and Jersey. Leaves were sampled for
mineral analyses in July.
Experiment 4 was established in a private
highbush blueberry planting in Montague, MA.
Only Bluecrop bushes planted in 1983 were
used. Four treatments were applied, each repli-
cated 10 times.
1. Ammonium sulfate, 105 g per bush.
2. 5-10-10 fertilizer, 450 g per bush.
3. Cod hydrolysate (3% N), 750 g per bush.
4. Herring hydrolysate (2.5% N), 900 g per
bush.
Hydrolysates were made up to contain twice
as much P as N, and the same amount of K as N.
Treatments all were designed to provide 0.8
ounce of N per bush; however, different treat-
ments provided different amounts of P and K,
and the hydrolysates also provided varying
amounts of other elements. Leaves were taken
in July for mineral analyses.
Concentrations of N, P, and K in blueberry
leaves are shown in Table 4. Magnesium, cal-
cium, boron, and manganese also were mea-
sured but are not shown in Table 4. There were
no differences among the treatments at the
HRC, where all treatments received equal
amounts of N, P, and K. In Montague, bushes
receiving only N (ammonium sulfate) had lower
P and K concentrations than ones receiving N, P,
and K. Bushes receiving 5-10-10 had slightly
higher boron concentrations than the others,
but since boron was not applied to these plants,
this result is apparently spurious.
There were no differences in mineral concen-
trations in bushes fertilized with fish hydroly-
sates vs. ones fertilized with inorganic N. Like-
wise, there was no evident difference in growth
or appearance of bushes among the treatments.
Discussion
These results indicate that fish waste hydro-
lysates are suitable for use as fertilizer in apple
orchards and highbush blueberry plantings.
Equivalent applications of inorganic N fertiliz-
ers and various sources of fish hydrolysates all
produced equivalent results. In areas where
these hydrolysates are available, they appear to
be equivalent alternatives to conventional inor-
ganic fertilizer sources. These materials could
Table 4. Comparisons of fish
hydrolysates and
inorganic
nitrogen as fertilizer sources
for bl
uebernes Leaf
analyses. 1991.
Element
Site
Materia
1
Significance'
(NHJjSO,
5-10-10
Cod hydrol.
Herring hydrol.
Shrimp hydrol.
Nitrogen
Belchertown
1.78%
...
1.81%
1.86%
1.76%
ns
Montague
1.75%
1.87%
1 79%
1.78%
...
ns
Potassium
Belchertown
0.68%
...
0.57%
0.62%
0.58%
ns
Montague
0.33%
0.73%
0.58%
0.61%
...
***
Phosphorus
Belchertown
0.11%
-
10%
0.10%
0.10%
ns
Montague
0.09%
0.10%
0.10%
0.10%
...
*
'Significance:
***, *, ns = odds of 999:1, 19:1, or not significant, respectively.
Fruit Notes, Summer, 1992
be especially useful in plantings that are being
grown as organically as possible, but they also
are suitable for use in conventional plantings.
We encountered several problems in use of
these materials.
1. They are malodorous, in particular the
herring hydrolysate (herring is an oily type of
fish) and the hydrolysate containing shrimp
waste. Also, in one instance the use of a hydro-
lysate attracted nocturnal wildlife that caused
damage to some adjacent plant material.
2. The hydrolysates contain particles that
rapidly settle in the containers. (The shrimp
hydrolysate was especially coarse.) They had to
be constantly stirred to avoid settling during
application. These particles also clogged strain-
ers, and the materials could not be applied with
a watering can unless the perforated opening
was removed. Since uniform results were ob-
tained, however, these problems were only of
concern as a nuisance.
Fish waste hydrolysates are available for
purchase from commercial suppliers. Gener-
ally, they are made up to contain about 2% N, 5%
P, and small amounts of other elements. Our
results indicate that they are usable for apples
and blueberries in the same manner as any
other fertilizer with a 2-5-0 analysis. Cost
comparisons should be based on price per
equivalent percent N. Our results suggest that
the other elements present in the hydrolysates
probably have little or no effect on perennial
plants.
Hydrolysates are provided as liquid fertil-
izer. The problems we encountered with par-
ticulate matter will not occur when commercial
materials are used. All are filtered so that they
can be applied through irrigation systems.
These materials are being used extensively by
cranberry growers in Massachusetts, and they
appear to be fully suitable for use on other
perennial fruit crops.
Fruit Notes, Summer, 1992
19
Fruit Notes
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c ruit Notes
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ISSN 0427-6906
Prepared by the Department of Plant & Soil Sciences.
University of Massachusetts Cooperative Extension System,
United States Department of Agriculture, and Massachusetts Counties Cooperating.
Editors: Wesley R. Autio and William J. Bramlage
'^HJCafC^
SEP 2
FENCES L/BR
Volume 57, Number 4
FALL ISSUE, 1992
Special IPM Certification Issue
Table of Contents
The Integrated Pest Management Education
and Certification Project, 1992 Update
Attitudes and Perceptions of New England Consumers
and the Food Industry Toward a Certification
Program for Integrated Pest Management
Massachusetts Grower Attitudes Toward a Certification
Program for Integrated Pest Management
Massachusetts Integrated Pest Management
Guidelines for Apple
Massachusetts Integrated Pest Management
Guidelines for Strawberry
European Community Guidelines for Integrated Fruit
Production (IFP): A Market-Driven Approach
Partners with Nature: A Massachusetts Integrated Pest
Management Recognition Program
PARTNERS
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Fruit Notes
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Fruit Notes
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COOPERATIVE EXTENSION SYSTEM POLICY:
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 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
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Issued by the University of Massachusetts Cooperative Extension System. Robert C. Helgtsen. Director, in
furtherance of the acts of May 8 and June 30. 1914. The University of Massachusetts Cooperative Extension System
offers equal opportunity in programs and employment.
The Integrated Pest Management
Education and Certification Project,
1992 Update
Craig S. Hollingsworth and William M. Coli
Department of Entomology, University of Massachusetts
The IPM Education and Certification
Project began in 1989 in response to growers'
requests for recognition of their IPM practices
and requests for additional IPM education. At
the outset of this project, we described the objec-
tives and planned activities [Fruit Notes
55(1):17-18]. This article is intended to bring
Massachusetts growers up to date on the accom-
plishments of the IPM Education and Certifica-
tion Project and to describe additional activities
planned for the future. Other articles in this
issue of Fruit Notes discuss specific activities of
this project in greater detail.
The objectives of the Massachusetts IPM
Certification and Education Project are: 1. to
develop a state-wide program for the education
of growers and agricultural professionals in the
principles of integrated pest management; 2. to
develop guidelines which identify crops grown
using IPM; and 3. to assist the Massachusetts
Department of Food and Agriculture in the
design and implementation of a program to
recognize IPM performance.
The IPM Short Course
A three and a half day short course was
designed to present the principles and concepts
of IPM to growers, agricultural professionals,
and others. While other crop-specific IPM
projects have educational components in their
newsletters and grower meetings, instruction is
normally focused on techniques specific to that
crop. Aside from formal university coursework,
instruction in the principles underlying IPM has
been unavailable. The IPM Short Course covers
the ecological and economic basis of IPM, sam-
pling, record keeping, biological control, pesti-
cides, as well as principles of insect, disease,
weed, and vertebrate management. Discussion
groups and videos are used where appropriate.
A manual containing IPM -related material, col-
lected from industry and leading University and
Extension programs, is supplied to participants,
and a display of IPM-related literature and
materials is maintained during the course.
In 1990, one course with 50 participants was
conducted, and in 1991, three sessions were
conducted, attended by a total of 138 partici-
pants. In 1992, two sessions were held, one in
Amherst (21 participants) and one in Wareham
(24 participants).
Courses have included participants from
Massachusetts, Maine, Vermont, Connecticut,
Rhode Island, New Hampshire, and New York.
Of the registrants in 1992, 87% were growers,
including producers of cranberries (40%), apples
(29%), vegetables, small fruit, flowers, orna-
mentals, and greenhouse crops. Attendees have
included representatives of Agricultural Stabili-
zation and Conservation Service (ASCS), Soil
Conservation Service, Massachusetts Depart-
ment of Food and Agriculture (MDFA), Univer-
sity of Massachusetts Cooperative Extension
System, University of New Hampshire Coopera-
tive Extension, University of Vermont Coopera-
tive Extension Service, and the University of
Massachusetts, Boston.
At the end of the course, participants evalu-
ated the course, including the question, "Would
you recommend this course to others? (l=not at
all, 5=very much)" Mean response to this ques-
tion was 4.8 and 4.2 for Amherst and Wareham,
respectively. Ratings were also favorable for
Fruit Notes, Fall, 1992
length of course (4.8 & 3.5),
expense of course (4.5, 4.5),
general organization (4.6 &
4.5), and usefulness of mate-
rial (4.4 & 4.2)
Additional IPM short
courses are planned for
January and February,
1993.
IPM Guidelines
At the request of MDFA,
IPM guidelines have been
developed, for apple, straw-
berry, potato, sweet corn,
cole crops, and cranberry.
These guidelines were devel-
oped as a list of best manage-
ment practices by interview-
ing crop specialists, includ-
ing university faculty, extension specialists, and
private consultants. Practices then were evalu-
ated as either "essential" or "recommended,"
and weighted according to their importance and
difficulty. The list again was reviewed by spe-
cialists and by growers participating in IPM
short courses. Guidelines were also sent to all
state commodity groups (e.g., Massachusetts
Fruit Growers' Association) with a request for
review and comment. Concerns raised by grow-
ers largely have been directed at whether spe-
cific practices are appropriate for them. We have
attempted to address this problem by using a
point system, so that no one practice is required.
Guidelines for six crops have been tested for
three seasons under the ASCS ICM cost-shar-
ing program, as well as in the University of
Massachusetts IPM program. In 1991, 57 farms
(2505 acres) completed the requirements for the
ICM program.
IPM guidelines for apple and strawberry are
published in this issue of Fruit Notes.
Surveys
In an effort to determine clientele percep-
tions toward IPM, and the need for IPM educa-
tion and certification, we conducted surveys of
consumers, different levels of the food industry,
and growers. Surveys
showed that all groups sup-
port the idea of IPM certifica-
tion. Over 80 percent of con-
sumers and the majority of
retailers, wholesalers, and
processors responding to sur-
veys endorsed "IPM-Grown"
labelling. Seventy-five per-
cent of growers said they
would enroll in an IPM certi-
fication program, and most
growers (81%) felt that they
are already practicing IPM.
Surveys also indicated a need
for consumer education and
marketing assistance.
Marketing
As the consumer survey
indicated, the general public does not know
much about IPM, but once informed, will sup-
port it. Thus, marketing and education are
likely to be critical to the success of a certifica-
tion or recognition program. Potential logo
designs were developed by a widely- represented
marketing committee and evaluated by faculty
of the Department of Consumer Studies at the
University of Massachusetts. The logo, "Part-
ners with Nature," was designed to "soften" the
idea of IPM and to emphasize its environmental
benefits. The final logo (see Figure) will be used
on all "IPM-Grown" marketing and point-of-
purchase material. Marketing materials will be
produced and distributed by the Massachusetts
Department of Food and Agriculture.
Implementation of the "Partners
with Nature" Progam
IPM recognition will be administered
through the Bureau of Agricultural Develop-
ment, MDFA. The University of Massachusetts
Cooperative Extension System will continue to
work in an advisory role to MDFA to develop an
implementation program. Details of the MDFA
plans for the "Partners with Nature" program
are discussed in this issue of Fruit Notes.
Fruit Notes, Fall, 1992
Attitudes and Perceptions of New
England Consumers and the Food
Industry Toward a Certification Program
for Integrated Pest Management
M.J. Paschall
School of Public Health, University of North Carolina
Craig S. Hollingsworth and William M. Coli
Department of Entomology, University of Massachusetts
Nancy L. Cohen
Department of Nutrition, University of Massachusetts
The Massachusetts Department of Food and
Agriculture in cooperation with the University
of Massachusetts Integrated Pest Management
(IPM) Program has been investigating the fea-
sibility of labelling produce grown under speci-
fied IPM practices. In an earlier issue of Fruit
Notes [55(1):17-18], we reported on the initia-
tion of this project, listing as the primary rea-
sons for developing the program recent con-
sumer concern over pesticide issues and the
desire of growers to be recognized as environ-
mentally responsible.
In 1990, we conducted a New England-wide
survey of consumers, farmstand owners, and
representatives of the New England food indus-
try to determine their perceptions and attitudes
toward integrated pest management (IPM) and
a proposed state program for "IPM-Grown" cer-
tification and labelling. It was also our intention
to use these survey results to help the Coopera-
tive Extension System to design and modify
IPM, food, and nutrition educational programs.
In 1990, 480 consumers were selected ran-
domly from Cooperative Extension mailing lists
from the six New England states. In addition,
102 farmstand owners and 36 wholesalers of
produce were selected randomly from lists pro-
vided by Departments of Agriculture in each
state, and 96 supermarket chain-store produce
managers and 36 fresh food processors were
selected randomly from the Grocery Index Direc-
tory of New England (1989-90).
A total of 750 surveys were mailed according
to guidelines described in Mail and Telephone
Surveys: the Total Design Method (Dillman,
1978). Postcards were sent to all prospective
respondents one week after the first mailing and
follow-up letters and surveys were sent to all
those who had not responded three weeks after
the first mailing. Responses to questions regard-
ing knowledge of IPM, perceptions of current
pesticide use and IPM, and attitudes toward
IPM certification are the focus of this report.
Overall response rate was 73%. Consumers
(74% response rate) represented the largest
proportion of respondents, followed by
farmstand owners (86% response rate), retailers
(61% response rate), wholesalers (83% response
rate), and food processors (47% response rate).
We first asked survey participants if they
had heard of integrated pest management be-
fore receiving the questionnaire. General
knowledge of IPM among consumers and food
industry representatives in New England was
Fruit Notes, Fall, 1992
very low: 77% had not heard of IPM. Similarly,
a survey in New York state (Burgess, 1989)
found that 73% of New York state consumers
had not heard of IPM. Clearly, if an IPM
labelling program is to be successful, there is a
need for extensive consumer education.
Farmstand owners, not surprisingly, generally
were knowledgeable about IPM (94% had heard
of it) from participation in Cooperative Exten-
sion training as well as other industry sources.
In order to understand how the various
groups perceived pesticide use, we asked respon-
dents how strongly they agreed or disagreed
with the following statements:
* There are no good reasons to use pesticides to
grow food.
* Pesticides in food are responsible for a high
incidence of human cancer.
* The government adequately regulates of the
use of pesticides.
* Farmers use pesticides safely.
* Most pesticides are safe if used according to
government regulations.
* Foods with very small amounts of pesticide in
them are safe to eat.
Based on their overall response to these
questions, respondents were classified as "per-
ceiving current pesticide use to be necessary,
safe, adequately regulated, and a minimal
health risk, "undecided," or "perceiving current
pesticide use to be unnecessary, unsafe, inad-
equately regulated, and a health risk."
A slightly larger proportion of respondents
(44%) considered current pesticide use to be
necessary, safe, adequately regulated by the
government, and a minimal health risk, com-
pared to those (40%) who did not. Farmstand
owners and retailers were more likely to con-
sider current pesticide use to be necessary, safe,
adequately regulated, and a minimal health
risk, compared to other respondents.
Respondents were given the following de-
scription of IPM:
Integrated Pest Management or IPM is an
approach to crop protection that uses informa-
tion about weather, pest numbers, and growing
conditions to make pest control decisions. Farm-
ers in IPM programs generally use non-chemical
and chemical methods to control pests. Non-
chemical methods include beneficial insects, re-
sistant crop varieties, crop rotation, cultivation,
and pruning. Pesticides are used only when pest
numbers reach levels which will cause signifi-
cant crop damage. Pesticides are selected and
applied in a manner that causes the least disrup-
tion to the environment.
In a number of crops, IPM programs have
been effective in reducing pesticide use. In Mas-
sachusetts, IPM programs for fruit and vegetable
crops have reduced pesticide use by 40 to 60
percent.
After reading this description, participants
were asked whether they agreed or disagreed
with a series of statements. Two-thirds (66%)
agreed with the statement, "When farmers have
determined that pest levels in a crop have reached
levels that will cause significant crop loss, the use
of pesticides is justified." Sixty- three percent
agreed with the statement, "Produce grown us-
ing IPM is safer than non-IPM-grown food." In
response to the statement, "Produce grown us-
ing IPM is as safe as organically-grown food,"
33% agreed; 34% were undecided; and 29%
disagreed or strongly disagreed.
It is striking that before reading about IPM,
32% of consumers agreed with the statement
that there is no reason to use pesticides on food,
but after reading about IPM, 60% felt that
pesticide use was justified under IPM. Still,
there was a clear difference between response by
the farming and non-farming respondents: the
majority of respondents (60-70%) in the non-
farm sectors agreed that pesticide use is justifi-
able under IPM guidelines, but nearly all (97%)
of farmstand owners felt pesticide use is justified
under IPM.
The majority of consumers, retailers, whole-
salers, and processors felt that IPM-grown pro-
duce is safer than non-IPM-grown food.
Farmstand owners were much more likely than
others to agree that IPM-grown produce is as
safe as organically-grown food, while many re-
spondents in all categories were undecided
about this statement. An Institute of Food
Technologists' report (Anonymous, 1990), how-
ever, indicates that many scientists do not con-
sider organic produce and, by our extrapolation,
Fruit Notes, Fall, 1992
Table 1. New England consumer and food industry attitudes toward IPM
labelling and certification.
Response
Consumer Farmstand Processor
Retail &
wholesale
Do you support the idea of IPM-Grown labelling?
Number of replies 338 88 16
YES(%) 84 57 69
NO(%) 5 21
Undecided (%) 11 23 31
Would you buy IPM-labelled produce if it cost the same?
Number of replies 340 87 15
YES(%) 86 65 73
NO(%) 5 20 7
Undecided (%) 9 15 20
Would you buy IPM-labelled produce if it cost somewhat (5%) more?
Number of replies 338 88 15
YES(%) 49 30 33
NO(%) 15 46 20
Undecided (%) 37 25 47
87
67
14
20
86
61
9
30
86
27
49
33
If an IPM program were started in your state, who should certify crops as meeting
IPM standards?
Number of replies
Dept of Agriculture (%)
Private Organization (%)
Farmer Organization (%)
Other (%)
Undecided (%)
331
84
14
84
51
58
71
70
6
5
7
6
13
10
5
14
8
14
8
15
19
7
11
IPM-grown produce, to be any safer to eat than
conventional produce. Prokopy et al. (1980)
pointed out that the advantages of using IPM
are lower pest control costs and fewer detrimen-
tal effects on the agricultural environment.
Among respondents, a strong majority (78%),
agreed with the statement, "The use of IPM
helps the environment."
Participants were presented with this para-
graph:
A number of states in the Northeast are ex-
ploring the possibility of offering programs to
qualified farmers to have their crops certified as
"IPM-Grown." Growers who meet specific stan-
dards would be able to advertise or label their
food as meeting these standards.
We then asked questions regarding IPM
labelling and certification (Table 1). Consumers
were very strong supporters of IPM labelling
Fruit Notes, Fall, 1992
(84%) and the majority of all respondents sup-
ported IPM-labelling, preferring EPM-labelled
produce when it cost the same as conventional
produce. If EPM-labelled produce cost somewhat
more (5%), nearly half of the consumers said
they would still buy it, but a large number of
respondents were undecided as to whether or
not they would. Twenty-five percent of consum-
ers responded that they were willing to pay 10-
20% more for IPM-labelled produce. In a New
York consumer survey (Burgess, 1989), 55% of
respondents were willing to pay up to 25% more
for IPM-grown produce. The majority of all New
England respondents felt that using state de-
partments of agriculture would be the most
appropriate method to certify IPM produce.
The results of this survey provide a chal-
lenge to the IPM certification program: to edu-
cate consumers that the food supply is safe and
that supporting IPM-labelled produce is an en-
vironmentally positive step. Fortunately, IPM
was perceived by the majority of the respon-
dents in all categories as a step toward protect-
ing the environment.
An IPM label may be useful for farmers who
adopt IPM methods to give consumers more
choices in the marketplace. First, however,
consumers and food industry personnel need to
be informed about IPM and other agricultural
practices to increase their confidence in the food
supply. How this will be best accomplished is an
open question. Recently, we have used these
survey results to provide IPM training to state
extension nutrition specialists, whose clientele
are consumers. We have also published an
article on IPM in the Journal of the American
Dietetics Association. Much more work will need
to be done in education and marketing before
consumers will recognize the benefits of IPM-
labelled produce.
References
Anonymous. 1990. Organically grown foods: a
scientific status summary by the Institute of
Food Technologists' expert panel on food safety
and nutrition. Food Technology 44(12): 123.
Burgess, R. 1989. Results of IPM marketing
survey. 51st annual New York Pest Manage-
ment Conference.
Prokopy, R. J., W. M. Coli, R. G. Hislop, and K.
I. Hauschild. 1980. Integrated management of
insect and mite pests in commercial apple or-
chards in Massachusetts. Journal of Economic
Entomology. 73:529-535.
Fruit Notes, Fall, 1992
Massachusetts Grower Attitudes
Toward a Certification Program for
Integrated Pest Management
Craig S. Hollingsworth and William M. Coli
Department of Entomology, University of Massachusetts
Vicki Van Zee
Massachusetts Department of Food and Agriculture
The Massachusetts Department of Food &
Agriculture, in cooperation with the University
of Massachusetts Cooperative Extension Sys-
tem Integrated Pest Management (IPM) Pro-
gram, has been investigating the feasibility
certifying and labelling produce grown under
specified IPM practices. Consumer concerns
over pesticide issues and the desire of growers to
be recognized as environmentally responsible
are among the reasons for developing such a
program.
In the previous article, we reported on the
attitudes and perceptions of New England con-
sumers and the food industry to IPM and a
proposed "IPM-Grown" label. That study
showed strong support for IPM certification, but
because it was a New England-wide survey, it
contained only a few responses from Massachu-
setts growers. Before such a certification or
recognition program is implemented in Massa-
chusetts, it is important to determine the sup-
port and concerns of the growers themselves.
In November 1991, questionnaires were
sent to all Massachusetts certified pesticide ap-
plicators in the tree fruit, small fruit, vegetable,
and cranberry categories. These categories cur-
rently have the most developed IPM programs
in Massachusetts. It should be noted that some
growers in the state do not use restricted-use
pesticides, hence, were not included in the sur-
vey. The survey followed a modified version of
the protocol described by D.A. Dillman (Mail
and Telephone Surveys: The Total Design
Method, 1978), which specifies survey instru-
ment design, mailing and follow-up procedures.
Three separate mailings were made, including
an initial mailing, a post-card reminder, and an
additional survey to individuals who did not
respond to the initial mailing.
The questionnaire asked growers 27 ques-
tions about their farming practices and adoption
of IPM, their opinions of a potential IPM certifi-
cation program, and what components of such a
program would be most useful to them. Some
questions asked for more than one response. A
brief paragraph describing IPM was also in-
cluded.
A total of 684 certified applicators responded
to the survey. Of these, 566 reported that they
were active in farming. The results reported
here are from this group of active farmers, of
which 141 (25%) were certified in apple, 54
(10%) in small fruit, 171 (30%) in cranberry, and
196 (35%) in vegetable. Note that rounding
errors and missing data points result in minor
discrepancies in the summarization of the data.
The age of the respondents ranged from 18 to
88 years, with a mean of 49 years. Their experi-
ence in farming was evenly distributed: 32% had
farmed for less than eleven years; 21% had
farmed for 12 to 19 years; 24% had farmed for 20
to 34 years; and 23% had farmed for more than
35 years.
Forty-two percent of the respondents sold
retail, 32% sold wholesale, 25% sold through a
cooperative, and 2% used other means. Of the
apple growers, 75% sold retail and 42% sold
wholesale. Among cranberry growers, 78% sold
Fruit Notes, Fall, 1992
through cooperatives and 24% sold wholesale.
Retail sales were the principal marketing
means used by 85% of the small-fruit growers.
Vegetable growers marketed through wholesale
(46%), retail (62%), and cooperative ( 14%) chan-
nels.
Nine percent of the growers had gross sales
over $500,000; 29% between $100,000 and
$500,000; 15% between $50,000 and $100,000;
14% between $25,000 and $50,000; 16% be-
tween $10,000 and $25,000; and 18% less than
$10,000.
Six percent of the growers had not completed
high school, 24% had completed high school,
24% had some college education, and 43% had
obtained a college degree.
In response to survey questions, 96% of
growers had heard of IPM before receiving the
survey, and 77% claimed to know a moderate to
an extensive amount about IPM. This result is
not surprising, as IPM education has been a
major focus of the Cooperative Extension Sys-
tem in Massachusetts since the late 1970's.
Table 1. Percentage
of grow-
ers of specific crops
indicating
that they practice IPM on that
crop.
Practice
Crop
IPM (%)
Apple
86
Other tree fruit
57
Blueberry
61
Strawberry
58
Other small fruit
50
Cranberry
98
Cole crops
82
Corn
77
Cucurbits
76
Pepper
86
Potato
77
Tomato
78
Tobacco
100
Other vegetables
64
Eighty percent of growers indicated that
they practiced IPM in 1991. A high percentage
of growers indicated that they practiced IPM on
a variety of crops (Table 1 ), many of which do not
have formal IPM programs in the state. While
we have no direct evidence that this high propor-
tion of growers are not practicing IPM, the level
of reported practice is much higher than we
expected. No specific IPM standards were pro-
vided in the survey, so, the high reported propor-
tion of IPM practice may be due to growers
assessing their performance according to their
own definitions of IPM. It seems likely that
many of these growers use some practices in-
cluded in IPM, but may not follow a complete
IPM program.
IPM practitioners were asked to list two
major reasons why they practiced IPM. Re-
sponses were grouped into categories: 77%
indicated economic benefits or time savings;
22% indicated environmental reasons; 13%
cited improved information; 10% indicated pes-
ticide safety reasons; 9% indicated other pesti-
cide issues; and 6% indicated food safety.
Cranberry growers placed more emphasis (21%)
on the improved information aspect of IPM.
The growers (n=58) who did not practice IPM
were asked for reasons why they did not. Their
reasons were placed in general categories: lack
of information, 50%; increased cost or effort,
24%; lack of trust or a bad experience, 14%; and
other, 16%.
Growers were asked a series of questions to
determine their opinions on pesticides and IPM
(Table 2). Over half of the growers acknowl-
edged that pesticides cause harm to the environ-
ment, evidence that growers are aware of previ-
ous problems caused by pesticides in certain
situations (e.g., EDB and aldicarb). A number of
growers felt, however, that pesticides have no
impact on the environment. Over eighty percent
of growers indicated that IPM was beneficial to
the environment. Interestingly, 4% of growers
felt that IPM harms the environment, perhaps
in recognition of the use of pesticides in IPM
programs.
Most growers (69%) felt that IPM does not
affect market quality. While most growers felt
that IPM does not increase the risk of crop
8
Fruit Notes, Fall, 1992
Table 2. Grower opinions on pesticides and EPM. "Which statements
most closely represent your opinions?"
Response
Question
(%)
The use of agricultural pesticides:
harms environment:
56
has no impact on the environment
28
helps the environment
9
Other
7
TheuseoflPM:
harms environment:
3
has no impact on the environment
11
helps the environment
83
other
2
Compared to conventionally-grown produce,
the use of IPM results in produce of:
poorer market quality
12
equal market quality
69
better market quality
14
other
5
When practicing IPM, the risk of
significant crop loss or failure:
increases
34
remains the same
46
decreases
18
other
2
IPM-grown food is:
not as safe to eat as conventionally-grown food
as safe to eat as conventionally-grown food
54
safer to eat than conventionally-grown food
44
other
2
failure, one-third of the growers felt that IPM
was riskier (Table 2). Cranberry growers were
more likely than other growers to feel that IPM
reduces risk of loss or increases market quality,
possibly because of long history of bog scouting
and the intensive private sector scouting pro-
grams currently used on cranberry bogs.
Growers agreed that IPM food is at least as
safe to eat as conventionally-grown food (Table
2) and over 40% felt that IPM-produced food is
safer. In our survey of the New England food
industry, 63% of all respondents and 54% of
farmstand owners believed that IPM-grown
food was safer than conventionally grown food.
Despite media and consumer perceptions, there
is good evidence from research that our, prima-
rily conventionally-grown, food supply is safe.
For example, samples for pesticide residues in
produce in Connecticut (H. M. Pylypiw, Jr. and
L. Hankin. Connecticut Agricultural Experi-
ment Station Bulletin 881 , 1990) show that most
produce has no insecticide residue at all, and less
Fruit Notes, Fall, 1992
than 1% of the produce
tested has pesticide levels
over USDA tolerances.
When asked if an IPM
certification and marketing
program would be useful,
68% of growers responded
favorably, 24% negatively,
and 8% were undecided.
Seventy-five percent of the
growers indicated that they
would enroll in an IPM certi-
fication & marketing pro-
gram (Table 3). Interest in
enrolling in a program was
consistent across commod-
ity groups and marketing
channels.
When asked how grow-
ers should be certified in
IPM, 38% indicated that
growers should pass a test of
IPM knowledge, 38% indi-
cated that growers should follow specific crop
production standards, and 5% thought that
growers should hire a consultant. Of those
growers who indicated that they would partici-
pate in a certification program, 45% indicated
that growers should pass a test of IPM knowl-
edge, 64% indicated that growers should follow
specific crop production standards, and 5%
thought that growers should hire a consultant.
Among cranberry growers, an industry with a
well developed crop consultant system, 25%
preferred the use of an IPM consultant; how-
ever, 58% of cranberry growers favored the use
of crop standards. In general, growers who had
used consultants for 1991 were more likely to
prefer the use of consultant as a qualification
standard (44%), but 50% still preferred the use
of crop standards. Younger growers and those
with more education were more likely than older
growers or growers with less education to prefer
the written test option. A significant problem
with tests as a "standard" is that tests would
favor more academically-oriented participants,
whether or not they put into practice what they
know of IPM.
When asked who should certify crops as
Table 3. Grower response toward
an IPM certification and
Marketing program.
"Would
you enroll in an
IPM certifica-
tion & marketing program?'
Yes
No
Undecided
Category
(%)
(%)
(%)
Crop grown:
Apple
81
13
6
Small fruit
83
13
6
Cranberry
72
22
6
Vegetable
71
17
12
Total
75
17
8
Marketing channel:
Wholesale
73
17
10
Retail
77
13
10
Cooperative
74
21
5
Other
64
27
9
1
IPM-grown, 39% of growers favored the Massa-
chusetts Department of Food & Agriculture,
39% favored a farmers organization, 5% favored
a private organization, 11% responded other,
and 17% were undecided. Cranberry growers, a
group with a strong growers association, gener-
ally preferred (50%) certification by a farmers
organization. Of the growers who would enroll
in a certification program, 46% favored the
Department of Food & Agriculture. In the
survey of consumers and the food industry in
New England, state departments of agriculture
were preferred by 56% of the respondents and
farmers organizations by only 12%.
Asked what an IPM certification program
should provide to growers that would be of the
most use, 69% indicated educational materials
for growers, 58% indicated courses and work-
shops about IPM, 35% indicated promotional
materials to retail and wholesale outlets, and
42% indicated educational materials for con-
sumers. Growers placed the same relative im-
portance on the choices, regardless of commod-
ity, marketing, or gross sales. Growers with
more education and those with fewer years in
farming preferred more marketing materials.
10
Fruit Notes, Fall, 1992
Results from this survey indicate a great
deal of interest and support by the farming
community for IPM certification. Many growers
indicated that growers and the Department of
Food & Agriculture should be involved in the
certification process. Also, whether they prac-
tice IPM or not, growers indicate a need for more
information on IPM. More entry-level IPM
educational programs, including videos and
training sessions, are planned by the Coopera-
tive Extension System's IPM program to meet
this need.
WITH
BETTER
FOR'OUR •
ENVIRONMENT
Fruit Notes, Fall, 1992
11
Massachusetts Integrated Pest
Management Guidelines for Apple
Craig S. Hollingsworth and William M. Coli
Department of Entomology, University of Massachusetts
Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Ronald J. Prokopy
Department of Entomology, University of Massachusetts
Integrated Pest Management is a systems noted by bold type. The required number of
approach to pest management that considers all points is approximately 70% of the total pos-
factors ultimately affecting the pest complex, sible, not including advanced IPM, optional, and
including plant nutrition and horticultural experimental practices which are worth bonus
practices, as well as elements of insect, disease, points,
and weed control. Control tactics include cul-
tural, biological, chemical, and mechanical Development of the Guidelines
methods. An IPM program must be flexible, as Guidelines were developed by interviewing
practices which are appropriate in some situa- apple specialists> inc l u ding university faculty,
tions may not always be practical or appropriate extension spec ialists, and private consultants to
in others. obtain a list of best management practices.
These guidelines are designed to evaluate Practices were then evaluated for their practi-
whether or not an apple crop has been grown ^ ^ weighted by their difficulty and im-
under IPM. The guidelines are used in the rtance to IPM Grower input was elicited
Agricultural Stabilization and Conservation through commodity associations and from par-
Service (ASCS) Integrated Crop Management tid t s in IPM short courses. The guidelines
(ICM) cost-sharing program and will be used in haye been tegted for three geasons ^^ the
the proposed Massachusetts Department of ^^ ICM cost -sharing program and the Uni-
Food & Agriculture IPM recognition program. vergity of Massac husetts IPM program to deter-
Whether a grower is enrolled in such a program mine whether or not the concept and the list of
or not, the guidelines can be used as a checklist practices are p rac tical.
to identify areas where pest management effi- Thege Adelines are not absolute. We ex-
ciency might be improved. t them to evolve with the development of IPM
As a measure of grower performance, the techno iogy. The authors welcome comments
guidelines use a point system, allowing a grower ^ suggest ion S for their modification or im-
to choose those practices which are most suit- Dr0V ement
able for a specific farm or situation. Credit or
partial credit may be earned for each practice, Acknowledgement8
based on its level of completion or on the portion °
of the farm on which it was used. Credit, We thank the following for their suggestions
however, must be earned in each general cat- and contributions to these guidelines: Wesley
egory. Higher values are given to practices Autio, Kathleen Leahy, Karen Hauschild, Mary
which we consider essential to IPM. These are Jane Else, and New England Fruit Consultants.
12 Fruit Notes, Fall, 1992
Massachusetts Integrated Pest Management Guidelines for Apple
To be recognized as an IPM grower, orchardists should accumulate 298 (70%)
IPM Practice Points of a possible 425. Points should be earned in each category.
Partial credit can be earned for a practice carried out on part of a farm, or partially
completed. Practices need to be documented by written records (e.g., scouting
records, dates and rates of applications of fertilizer, and dates of sprayer calibra-
tions). Practices marked in bold type are considered basic IPM practices.
Practices marked with an asterisk (*) are advanced IPM (second level) or
experimental practices. These practices are presently under evaluation, but appear
to be capable of reducing pesticide use significantly beyond that of basic (first level)
IPM practices. Bonus points are awarded for completion of these practices.
NUTRIENT MANAGEMENT AND CULTURAL PRACTICES
1. Trees are pruned so that spray penetration and air
circulation are adequate. 5 pts
2. Primings are removed or destroyed such that no residue is
present after one year. 5 pts
3. Summer pruning is done on densely foliated, vigorous trees. 10 pts
4. A complete leaf tissue analysis is performed in the current year. 10 pts
5. Fertilizer amendments are applied according to previous year's
leaf tissue analysis. 10 pts
6. Orchard renovation (4% of the orchard or greater) includes dwarfing
rootstocks (M.26 or smaller) in at least 50% of the new plantings. 10 pts
PESTICIDE APPLICATION AND RECORDS
Only pesticides approved and registered in the state will be used. Records of pesticide
applications (including date, block identification, targeted pest, pesticide name and EPA
number, rate, and number of acres treated) are maintained. Pesticide drift is minimized.
1. Orchard sprayer is calibrated accurately at the start of the
season. 10 pts
2. Herbicide sprayer is calibrated accurately at the start of the
season. 10 pts
3. Orchard sprayer is recalibrated at mid-season. 10 pts
4. The grower has calculated tree-row volume for each block and
applications conform to tree-row volume calculations. 10 pts
INSECT MANAGEMENT
Monitoring
Insect monitoring must be carried out in a scientifically valid manner. Records should be
kept of all monitoring information collected.
Fruit Notes, Fall, 1992 13
1.
Tarnished plant bug adults are monitored by white visual
traps.
lOpts
2.
European apple sawfly is monitored by white visual traps.
lOpts
3.
Fruit is monitored for plum curculio injury.
20pts
4.
Foliage is sampled for mites and mite predators.
lOpts
5.
Apple maggot is monitored by red sphere traps.
20pts
6.
Leafminers are monitored by red visual traps or foliar
monitoring of first generation mines.
lOpts
7.
Terminal foliage is monitored for aphids and aphid predators.
lOpts
8.
Foliage is monitored for white apple leafhopper and potato
leafhopper.
lOpts
9.
Bark of trunk and limbs are monitored for San Jose scale,
woolly apple aphid, and borers, where appropriate.
lOpts
10.
San Jose scale is monitored by black tape traps or pheromone,
where appropriate.
5pts
11.
Orchard is monitored with pheromone traps for codling moth
and red-banded and oblique-banded leafrollers.
5 pts
12.
Fruit and foliage and monitored for fruitworm and leafroller
larvae, where appropriate.
5pts
Control
1.
Application of insecticides corresponds to thresholds
ranges specified in State apple IPM publications.
25 pts
2.
At least one application of dormant oil is applied.
10 pts
3.
Border spray is used for one or more of the pesticide
applications against plum curculio.
10 pts
4.
Biological control by naturally occurring predators is
used for control of aphids, when conditions permit.
10 pts
5.
Synthetic pyrethroids are not applied.
10 pts
6.
At least one insecticide or miticide application is made by alternate
row spraying.
10 pts
7.
Where appropriate, application of pesticides for mites, aphids or
apple maggot are reduced by one-half of the labeled rate, as
defined in the March Message.
10 pts
8.
Summer oil is used as a substitute for other acaricides in
suppressing mites after petal fall.
10 pts
*9.
Orchard is surrounded by odor-baited red sphere traps at a rate
of 1 trap per 15 ft in lieu of pesticide application.
20 pts
14 Fruit Notes, Fall, 1992
no.
Apple maggot pressure is reduced by removing dropped fruit from
the orchard within 10 days of dropping,
or before end of harvest.
20 pts
lOpts
•11.
All abandoned apple trees within 100 yards of the orchard
border are removed to prevent codling moth immigration.
15 pts
DISEASE MANAGEMENT
1.
A fixed-copper fungicide is applied either the previous
fall or before bud break.
10 pts
2.
First fungicide spray is delayed an appropriate time
according to ascospore development and from previous
year's ascospore density and scab incidence.
15 pts
3.
Fungicides for scab management are applied only until the
end of primary scab season (as defined by ascospore
maturity and release) unless visible infections develop.
15 pts
4.
Mill's infection periods are used to guide fungicide
application decisions.
10 pts
5.
Grower uses a delayed sterol inhibitor fungicide program
or a protectant program based on ascospore maturity,
tree phenology, and environmental information for
primary scab management. The appropriate number of
fungicide applications per season may vary between 2
and 7 per year, depending on conditions.
10 pts
6.
Trees are monitored for cedar apple rust. Where cedar apple rust
is a problem, red cedar and juniper within 100 yards
surrounding orchard are removed.
5 pts
•7.
Litter chopping or chemical treatment is practiced so as to reduce
scab residue.
5 pts
•8.
Treatments for fire blight follow blight forecast in Tree Fruit
Pest Message.
5 pts
*9.
Experimental block of disease-resistant trees is planted.
5 pts
WEED MANAGEMENT
1.
Herbicides of the same class are not used in successive years.
10 pts
2.
Nonchemical weed management techniques (e.g., mowing, mulches)
are used. Agents toxic to predatory mites are avoided. Spot
treatment of noxious weeds (e.g., poison ivy, bindweed) is permitted.
10 pts
WEATHER AND CROP MONITORING
1.
Grower monitors high and low daily temperatures and leaf
wetness (modified hygrothermograph or equivalent).
Fruit Notes, Fall, 1992 15
Records are kept on a daily basis.
15 pts
2. Records of the stage of tree development are maintained on a
weekly basis.
5 pts
EDUCATION
1. One or more Cooperative Extension System IPM
workshops is attended during the current year.
5 pts
2. Grower possesses current New England Apple Pest
Management Guide.
5 pts
3. Grower subscribes to the Cooperative Extension System's
Tree Fruit Newsletter. 5 pts
IPM points- 425
Bonus points - 70
TOTAL POSSIBLE - 495
16 Fruit Notes, Fall, 1992
Massachusetts Integrated Pest
Management Guidelines for Strawberry
Craig S. Hollingsworth
Department of Entomology, University of Massachusetts
Sonia G. Schloemann and Daniel R. Cooley
Department of Plant Pathology, University of Massachusetts
Mary Jane Else
Department of Plant & Soil Sciences, University of Massachusetts
Integrated Pest Management is a systems
approach to pest management that considers all
factors ultimately affecting the pest complex,
including plant nutrition and horticultural
practices, as well as elements of insect, disease,
and weed control. Control tactics include cul-
tural, biological, chemical, and mechanical
methods. An IPM program must be flexible, as
practices which are appropriate in some situa-
tions may not always be practical or appropriate
in others.
These guidelines are designed to evaluate
whether or not a strawberry crop has been
grown under IPM. The guidelines are used in
the Agricultural Stabilization and Conservation
Service (ASCS) Integrated Crop Management
(ICM) cost-sharing program and will be used in
the proposed Massachusetts Department of
Food & Agriculture IPM recognition program.
Whether a grower is enrolled in such a program
or not, the guidelines can be used as a checklist
to identify areas where pest management effi-
ciency might be improved.
As a measure of grower performance, the
guidelines use a point system, allowing a grower
to choose those practices which are most suit-
able for a specific farm or situation. Credit or
partial credit may be earned for each practice,
based on its level of completion or on the portion
of the farm on which it was used. Credit,
however, must be earned in each category.
Higher values are given to practices which we
consider essential to IPM. These are noted by
bold type. The required number of points is
approximately 70% of the total possible, not
including advanced IPM, optional, and experi-
mental practices which are worth bonus points.
Development of the IPM Guidelines
Guidelines were developed by interviewing
fruit specialists, including university faculty,
extension specialists, and private consultants to
obtain a list of best management practices.
Grower input was solicited through commodity
associations and from participants in the IPM
short courses. Practices were evaluated for
practicality and weighted by their difficulty and
importance to IPM. The guidelines have under-
gone a number of drafts and have been tested for
three seasons under the ASCS ICM cost-sharing
program, the University of Massachusetts IPM
program.
These guidelines are not absolute. We ex-
pect them to evolve with the development of IPM
technology. The authors welcome comments
and suggestions for their improvement.
Fruit Notes, Fall, 1992
17
Massachusetts Integrated Pest Management Guidelines for Strawberry
Crops must accumulate 228 IPM Practice Points, or 70% of a possible 325. [Points
for practices which are clearly inappropriate for a given farm do not count toward
the total, e.g., if a farm has no history of red stele, disease-resistant cultivars are
inappropriate, thus the total points possible are 320, and 224 (70%) are required.]
Points must be earned in each category. Partial credit can be earned for a given
practice by completing a percentage of that practice. Practices printed in bold are
considered essential IPM practices.
NUTRIENT MANAGEMENT AND CULTURAL PRACTICES
1. A complete leaf tissue analysis was performed in the previous
year and fertilizer applications in the current year were guided by
the results of that analysis. 5 pts
2. A complete leaf tissue analysis is performed in the current year. 5 pts
3. Land that was in strawberries in previous year, but where
the planting was terminated, is now in a planned rotation
out of strawberries (1 year is strongly recommended; 5 years
out of strawberries is recommended, where possible). 10 pts
4. Strawberries are mulched with weed-free, biodegradable
mulch (e.g., straw) for winter protection. 10 pts
5. Mulch layer is maintained within the row (bare spots
between plants) and between rows in bearing beds from
early spring (when it is raked off the top of the row)
until renovation to suppress weeds and prevent splashing
of water from rain or irrigation. 10 pts
6. To optimize air drainage and circulation, planting pattern is in the
form of a narrow matted or ribbon row. Canopy width does not
exceed 2 ft. Rows are planted a minimum of 4 ft apart on center. 15 pts
7. At bed renovation, leaves that are mowed are removed from the
field to reduce disease inoculum. 5 pts
PESTICIDES AND PESTICIDE RECORDS
Only pesticides registered in the state and approved for the target pest and crop will be used.
Records of pesticide applications including date, field identification, targeted pest, pesticide
name and EPA number, formulation, rate, and number of acres treated are maintained.
1. Insecticide sprayer is calibrated at the start of the season. 10 pts
2. Herbicide sprayer is calibrated at the start of the season. 10 pts
DISEASE MANAGEMENT
1. Where history of red stele, Verticillium wilt, or leaf diseases
warrants, cultivars which have tolerance or resistance to the
appropriate disease are used. 5 pts
18 Fruit Notes, Fall, 1992
2.
Land planted to strawberries in the current year was in a rotation
that included at least 1 year without a crop in the following
families: Rosaceae (strawberries, raspberries, etc.), Solanaceae
(potato, tomato, peppers, eggplant), Cruciferae (cabbage,
broccoli, etc.), and Leguminaceae (peas, beans, etc.)
lOpts
3.
Strawberry plantings are made on beds that are raised enough to
optimize water and air drainage.
5 pts
4.
Fungicide is applied for Botrytis cinerea (gray mold) 1
to 3 times during bloom starting at 10% bloom, if
appropriate weather conditions are present.
lOpts
5.
If environmental conditions are not favorable for fruit rots,
no fungicide is applied after bloom.
15 pts
INSECT MANAGEMENT
Insect monitoring methods and thresholds must conform to State IPM progran
i guidelines.
Records should be kept of all monitoring information collected.
1.
Tarnished plant bug adults are monitored weekly by using white
sticky traps starting on or about April 15 and continuing until
10% bloom.
5 pts
2.
Tarnished plant bug nymphs are monitored weekly
using flower truss counts starting at 10% bloom and
continuing until harvest begins.
15 pts
3.
Strawberry bud weevils (clipper) are monitored weekly
starting pre-bloom and continuing until 50% bloom.
15 pts
4.
Two-spotted spider mite populations are monitored
weekly starting pre-bloom and continuing until renovation.
15 pts
and bimonthly after renovation (when foliage has re-grown)
until mid-September
10 pts
5.
Mite predator populations are monitored according to the same
schedule as two-spotted spider mite populations.
15 pts
6.
Applications of insecticides for tarnished plant bug and
clipper, correspond to thresholds specified by the State
Strawberry IPM program.
25 pts
7.
Predator mites are released for two-spotted mite management
when action threshold is exceeded.
10 pts
8.
When two-spotted mites are present in the field,
insecticides and fungicides used in that field are selected
according to low toxicity to mite predators.
15 pts
WEED MANAGEMENT
1.
Prior to planting new land to strawberries, fields are
planted to a plowed summer cover crop such as
Fruit Notes, Fall, 1992 19
Sudan grass, Sudex, buckwheat, or oats; or a plowed
winter cover such as winter rye, winter rye plus hairy
vetch, winter wheat, winter wheat plus hairy vetch, oats,
or oats plus hairy vetch for one growing season.
15pts
2.
Weeds are controlled through cultivation or effective herbicide
application in bearing beds from renovation until a new layer of
mulch is applied in early winter.
5pts
3.
A weed survey is conducted at least once during the
growing season specifying significant weed species,
indicating location of significant weed problems and
noting recommended management practices.
15 pts
4.
Weed management practices, including herbicide selection
and rates, are based on the previous year's weed survey.
15 pts
5.
Herbicides of the same class are not applied in succeeding years.
5 pts
EDUCATION
1.
Grower attends one or more Cooperative Extension System
IPM workshops during the current year.
5 pts
2.
Grower possesses a current Strawberry IPM Management
Guide.
5 pts
3.
Grower possesses current New England Small Fruit
Recommendations .
5 pts
4.
Grower subscribes to the Cooperative Extension System's Small
Fruit Newsletter and receives the weekly Strawberry IPM Pest
Message during the growing season.
5 pts
20 Fruit Notes, Fall, 1992
European Community Guidelines for
Integrated Fruit Production (IFP):
A Market-Driven Approach
William M. Coli
Department of Entomology, University of Massachusetts
In June, Ron Prokopy and I attended the
Nineteenth International Congress of Entomol-
ogy, held in Beijing, Peoples Republic of China.
At the Congress, Dr. Erich Dickler from Ger-
many described the extent to which Integrated
Fruit Production (IFP) techniques are practiced
in Europe. IFP is defined as "the economical
production of high quality fruit, giving priority
to ecologically safer methods, minimizing the
undesirable side effects and use of
agrichemicals, to enhance the safeguards to the
environment and human health."
Dr. Dickler indicated that certain countries
(e.g., Italy), grow up to 60% of their pome fruits
according to IFP guidelines established by the
International Organization for Biological Con-
trol (IOBC) and the International Society for
Horticultural Science (ISHS). Growers using
IFP benefit in the marketplace because of inter-
est on the part of "Green" (i.e., environmentally
conscious) consumers in products grown using
reduced or no pesticides.
For those not familiar with the term, the
"Green" Movement started a number of years
ago as a way for European citizens to respond to
environmental degradation on the continent.
Several countries have "Green" political parties
which have elected representatives to parlia-
ment. At the same time, "Green" products,
including fruits and vegetables, have found
their way into commerce.
According to Dr. Dickler and other European
scientists, the market for "Green" produce is
strong and getting stronger. Some countries
(e.g., Poland), which have not experienced such
extensive environmental degradation as others
(e.g., the former East Germany) and which to
date have used many fewer tons of pesticides
than their neighbors, are attempting to keep
pesticide use below western European levels as
a way to take advantage of the "Green" market
in the European Economic Community (EEC).
The "Green" market is so strong that certain
buyers will only buy pome fruits grown under
Integrated Fruit Production. Hence, farmers
who wish to achieve higher prices and overcome
price softness in years of high production, are
reportedly turning to the IFP Guidelines.
The concept that growers using integrated
farming techniques should be recognized in the
market place is one of the underlying reasons
why the University of Massachusetts has been
pursuing the possibility of IPM recognition since
the late 1980's. Specific details and updates on
the status of this work are described in other
articles in this issue. For the remainder of this
article, I will describe the EEC IFP (First Edi-
tion, January, 1991) guidelines and point out
their similarities and dissimilarities with cur-
rent Massachusetts Apple IPM Guidelines.
The IFP guidelines are similar to Massachu-
setts IPM Guidelines in that they have a num-
ber of sections (13) covering many aspects of
fruit production and protection. Generally
speaking, they are much more comprehensive
and restrictive than Massachusetts IPM Guide-
lines. For example, the IFP guidelines cover
site, rootstock, cultivar, and planting systems
for new orchards; irrigation; tree training and
management; efficient and safe spray applica-
tion methods; conserving the orchard environ-
ment; and harvesting, storage, and fruit qual-
ity. Much of the contents of the above sections
are common sense, e.g., pick favorable sites,
Fruit Notes, Fall, 1992
21
avoid frost pockets, plant small trees, supply
adequate soil moisture to insure steady growth,
conduct regular soil analyses, do not spray un-
der windy conditions, harvest fruit at the correct
time to maintain high internal and external
fruit quality, etc.
Certain aspects of these and other sections,
however, require the grower to avoid certain
materials and practices. For example, sprayers
which produce a very fine droplet size and clean
cultivation of orchards both are not permitted.
The guidelines are most restrictive in dealing
with agricultural chemicals, separating chemi-
cals into either a green list (permitted), yellow
list (restricted), and a red list (not permitted).
Chemical classification is based on nine criteria,
including toxicity to key natural enemies, toxic-
ity to man, pollution of ground and surface
water, ability to stimulate pests, persistence,
and selectivity.
Among the list of materials which are not
permitted are chemical thinners and synthetic
growth regulators (except under certain condi-
tions); pyrethroid and organochlorine insecti-
cides and acaricides; residual herbicides and
herbicides which contaminate groundwater (ex-
cept simazine in both instances); and post har-
vest chemical treatments.
Permitted with restrictions are the benzimi-
dazole fungicides (for blossom wilt and storage
rot only); dithiocarbamate fungicides (maxi-
mum of 3 applications per season, and not in
succession); and sulphur [limited to 3 kg/ha (2.7
Pounds /acre) per application, and not more
than 3 sprays per season].
Can Massachusetts fruit growers conform to
EEC IFP guidelines? Clearly, some could, while
others could not. A more important question is
whether typically independent growers would
be willing to have so many management deci-
sions preempted by some other entity. Growers
may be interested to compare the EEC IFP
guidelines with Massachusetts IPM standards,
which were developed in a manner so as to be as
unrestrictive as possible while still defining the
essence of IPM.
For the foreseeable future, the EEC guide-
lines will have little or no impact on the Massa-
chusetts or the U.S. fruit industry. It is interest-
ing to note that the International Society for
Horticultural Science has asked Dr. Jerome
Hull of Michigan State University to summarize
the state of the art of Integrated Fruit Produc-
tion in the U.S. The EEC is rapidly becoming
more and more unified and governed by commu-
nity-wide laws, taxes, and standards. Although
IFP guidelines are market driven and not man-
datory, the day may come when fruit exported
from the U.S. will be expected to conform to
standards imposed by buyers. European bro-
kers of Certified IFP fruit could also attempt to
gain a market share in the U.S. We believe it is
important for Massachusetts growers to be
aware of changes occurring elsewhere in the
world and to be prepared to respond to future
marketing opportunities and challenges.
22
Fruit Notes, Fall, 1992
Partners with Nature:
A Massachusetts Integrated Pest
Management Recognition Program
Vicki Van Zee
Massachusetts Department of Food & Agriculture
The Massachusetts Department of Food &
Agriculture (DFA) will be implementing a pilot
program in 1993 to recognize growers who are
practicing integrated pest management (IPM).
DFA has supported the concept of IPM for the
same reasons that more and more growers are
using it, i.e., it makes good economic sense and
it is environmentally sound. The title of this
program, "Partners with Nature," was chosen to
convey the environmental benefits of IPM.
Most of the Massachusetts growers recently
surveyed (refer to pages 7 through 11 in this
issue of Fruit Notes) perceive themselves as
practicing IPM. In the absence of a formal
definition or standard of IPM, the IPM label has
been loosely assigned. Growers participating in
IPM programs have asked for a consistent way
to identify their produce. In the same survey,
over 500 participants indicated they would en-
roll in such a program. The goals of the
program are to promote the adoption of IPM
among growers and to increase consumer
awareness and demand for IPM-grown produce.
By establishing a consistent IPM label, both
growers and consumers can have a common
understanding of its meaning. Recognition of
IPM growers will help foster better community
relations as growers may use the program to
demonstrate their concern for the environment.
The program will educate consumers to help
them better understand how purchasing IPM-
grown produce benefits both our local growers
and our environment.
DFA will administer the program by identi-
fying crops according to guidelines developed by
the IPM Specialists in the Cooperative Exten-
sion System. In order to get this IPM program
off to a solid start, DFA will begin a pilot pro-
gram focusing on three crops in the 1993 grow-
ing season. Strawberries, sweet corn, and
apples have been selected for the first year.
These crops were chosen because well-devel-
oped IPM techniques and resources exist for new
as well as experienced IPM growers. As the
administrative capacity of DFA expands and the
process is strengthened, the program will in-
clude more crops in the following years.
Participation in the program is voluntary.
Qualifying growers will receive marketing ma-
terials (i.e., posters, pamphlets, stickers) for
their produce and educational brochures for
their customers and employees. Certificates
will be issued on individual crops which have
been raised according to IPM program guide-
lines. These certificates will serve as official
recognition of IPM growers. Proposed IPM
guidelines for strawberries and apples are pub-
lished in this issue of Fruit Notes.
DFA intends to make the process as manage-
able as possible for growers. At the same time,
verification of procedures will be required of
participants in order to validate the issuance of
IPM-grown certificates. The process will involve
the following:
October - November, 1992
The Partners with Nature program will be
announced.
Introductory information about the process
will be available from DFA upon request.
December, 1992 • February, 1993
Applications will appear in growers associa-
tions' newsletters, The Farm and Market
Fruit Notes, Fall, 1992
23
Fruit Notes
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