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NOTES
PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES
COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.
EDITORS
W. J. LORD AND W. J. BRAMLAGE
Vol. 48 No. 1
WINTER ISSUE, 1983
Table of Contents
FRUIT NOTES Subscription
Varieties of Grapes for Massachusetts
Varieties of Peaches for Massachusetts
Performance of Disease Resistant Apples
in Massachusetts
Disease Management for Apples in Massachusetts:
1982 Results and Summary of the Five-Year Program
Factors Affecting Nutrient Content of the Foliage
and Fruits of Apple Trees
Pomological Notes
Integrated Management of Apple Pests in Massachusetts,
1982 Results: Insects
Issued by the Cooperative Extension Service, Daniel I. Padberg, Director, in furtherance
of the Acts of May 8 and June 30, 1 91 4; United States Department of Agriculture and
County Extension Services cooperating. The Cooperative Extension Service offers equal
opportunity in programs and employment.
The cost of publishing FRUIT NOTES has become a significant
portion of the Smith-Lever allocation for my extension
program. If we continue to send it free- of - charge very
little money will be left for travel, attendance at meetings,
and supplies. Thus, starting with the Spring Issue, FRUIT
NOTES will be on a subscription basis at $3.00 per year for
4 issues. Hereafter, the subscription year will commence
with the Winter Issue. A notice for renewing your subscription
will appear in the fall issue of the previous year.
To subscribe to FRUIT NOTES, complete and mail the following
form with your check for $3.00.
William J. Lord
William J. Bramlage
Editors, FRUIT NOTES
WJL/pm
Name
Mailing address
Town, State, Country zip
Make checks payable to: FRUIT NOTES ACTIVITY ACCOUNT
Send subscription form and check to: William J. Lord
Department of Plant and Soil Sciences
French Hall
University of Massachusetts
Amherst, MA 01003
VARIETIES OF GRAPES FOR MASSACHUSETTS
James F. Anderson
Department of Plant and Soil Sciences
The following is a list of varieties that are currently
recommended for planting in Massachusetts. Many new seeded and
seedless varieties have been introduced in recent years. Some
of these may be equal to or better than the one listed. Those
growers interested in grapes for wine should obtain a copy of
the Catalog of New and Notev\forthy Fruits from the New York State
Fruit Testing Cooperative Association, Inc., Geneva, NY 14456.
This catalog offers a description of the French-hybrid and
other varieties suitable for wine production.
Variety
Recommended for
Harvest Season
Schuyler
Himrod
Van Buren
Ontario
Seneca
Suffolk Red
Fredonia
Buffalo
Delaware
Lakemont
Worden
Blue Boy (Cook)
Niagara
Concord
Steuben
T = Trial
T
H
C& H
H
H
T
C& H
H
C&H
T
C&H
C&H
C&H
C&H
T
H = Home garden
late-August
late August— early September
late August— early September
late August— early September
late August— early September
late August— early September
early September
early September
mid-September
mid-September
mid-September
mid-September
late-September
late-September
late-September
C = Commercial
All varieties are not necessarily equally adapted to all sections of the state. Late ripening varieties are recommended
only for those areas with a sufficiently long growing season to permit satisfactory ripening of the fruit.
Variety Notes
Schuyler — A very early, high-quality, black grape. The clusters are medium to large and moderately compact. The
berries are medium in size, tender, and juicy. The vine is vigorous, productive, and medium in hardiness.
Schuyler require severe pruning to prevent overbearing.
Himrod — An early-ripening, seedless grape resulting from a cross between Ontario and Thompson Seedless. Its
clusters are large and rather loose. The berries are medium, oval, sweet, yellow, vinous, and good. The
vine is not completely winter-hardy under our conditions and should be restricted to the more favored
sites.
Van Buren - An attractive, black grape of good to excellent quality. The vine is vigorous and productive. It is particu-
larly susceptible to downy mildew.
An early-ripening, white grape of high quality. The plust^rs are medium in size and tend to be loose. The
berries tend to shatter considerably within a few days after harvest. The vines are medium in vigor and
productivity, and are hardy.
An early-ripening, white grape with a thin, tender, adherent skin. The berries are medium in size, oval,
and have excellent flavor. The clusters are medium in size and compactness. Seneca is susceptible to win-
ter injury.
Suffolk Red - A bright-red, seedless grape. The clusters are medium in size and tend to be loose. The berries are medium
in size, round, and have very good quality. The vine is medium in hardiness.
Ontario —
Seneca
Fredonia — A good-quality, black grape especially recommended for the roadside stand trade. The clusters are com-
pact and medium in size. The vine is vigorous, hardy, and productive. It should be pruned less severely
than Concord.
Buffalo — A black grape with medium to large size, sweet, vinous flavor and good adherence. The clusters are large
and tend to be loose. The vine is vigorous and productive, and the fruit holds very well in storage. Buffalo
tends to overbear and to be susceptible to winter injury if not properly pruned.
Lakemont — A yellowish-green, seedless grape. Its clusters are medium to large and moderately compact. The berries
are medium to small in size, oval, tender, juicy, and sweet. The vine has moderate vigor and hardiness.
Tends to overbear.
Delaware — A high-quality, red grape with small clusters and berries. The vines are hardy and are moderate in vigor
and production. Delaware would add to the attractiveness of displays on a roadside stand.
Worden — Similar to Concord, but ripens a week to ten days earlier. While slightly superior to Concord in quality
and attractiveness, it has a tendency to crack when ripe and shatters badly within a few days after it is
harvested. A desirable variety for local trade and the home vineyard.
Blue Boy — This is an attractive, black grape with an abundance of bluish bloom. Adherence of the berries is good and
(Cook) the quality is excellent. Vines are productive and the fruit holds in storage unusually well. Recommended
for commercial planting and is a desirable variety for the home vineyard.
Niagara — A white grape of high quality with large compact clusters. Would add to attractiveness of display on a
roadside stand. Ripens with Concord.
Concord — The particular merits of Concord are its adaptability to a wide variety of soils, its productiveness, hardi-
ness, vigor, and shipping quality. Concord requires a growing season of approximately 160 days for
proper ripening of its crop.
Steuben — Those growers who can mature Concord might wish to try this variety. The grapes are bluish-black in
color, medium in size, and have very good quality. The clusters are medium to large, compact, and attrac-
tive. The vines are usually hardy, vigorous, and productive.
■A *********
Variety
■ A-
VAR urn lis 0|- PHACIIHS for MASSACimSr.TTS
.James F. Anderson
nepartmcnt of Plant and Soil Sciences
Recommended for
2
Flesh color
Approximate harvest date
3
Harbinger
Candor
Garnet Beauty
Sweethaven
Brighton
Harbelle
Reliance
Raritan Rose
Redhaven
Harken
Harbrite
Velvet
Jayhaven
Glohaven
Eden
Richhaven
Canadian Harmony
Cresthaven
Jerseyglo
Autumnglo
C — Commercial
1
C Y
T Y
C Y
T Y
T" Y
C Y
H Y
C W
C Y
C Y
C Y
C Y
T Y
C Y
T W
C Y
C Y
C Y
T Y
T Y
H — Home garden
-30
-20
-13
-13
-13
-8
-4
-2
+3
+5
+7
+7
+10
+11
+12
+16
+21
+26
+30
T - Trial
All varieties are not necessarily equally adapted to all sections of the state.
2 V - Yellow flesh
W - White flesh
Based on harvest date for Redhaven (approximately August 20, but can vary from location to location and season
to season). Minus sign indicates number of days before; plus sign indicates number of days after Redhaven.
Harbinger —
Candor* —
Garnet Beauty —
Sweethaven* —
Variety Notes
An attractive, small to medium-sized clingstone peach. The flesh is yellow, firm, melting, and has
very good flavor for this season. The tree is vigorous, productive, and equal to Redhaven in bud
hardiness.
The fruits are well-colored, and small to medium in size. The flesh is yellow, firm, and juicy and
the stone is semi-cling. The buds are hardy and the tree vigorous and productive.
A bud-sport of Redhaven. Resembles Redhaven in color and texture. It is a semi-clingstone. The
tree is vigorous, productive, and hardy.
An early, yellow-fleshed, semi-clingstone peach. The fruits are medium in size, roundish, and well
colored. The flesh is juicy, slightly fibrous, but soft. The tree is vigorous, productive, and similar
to Redhaven in bud hardiness.
Brighton* —
Harbelle —
Reliance —
Raritan Rose —
Redhaven —
Harken —
Harbrite —
Velvet -
Jayhaven* —
Glohaven —
Eden* -
Richhaven —
Canadian Harmony
Cresthaven* —
Jerseyglo* —
Autumnglo* —
An attractive, high-quality, yellow-fleshed peach. The fruit is roundish, uniformly medium in
size, and highly colored. The flesh is medium firm, juicy, with very good flavor. The pit is semi-
cling. The tree is vigorous, productive, and medium-hardy.
The fruit is large, attractive, with deep-yellow ground color and a bright-red blush. Flesh is a rich
yellow, medium in firmness, of good quality. The stone is semi-free. The tree is productive, and
medium in vigor and bud hardiness.
A medium-sized, roundish, yellow-fleshed freestone peach of fair to good flavor. Reliance is
recommended as a very hardy variety for the home fruit planting.
The fruit is large, round, attractive. The flesh is white, firm and juicy. The tree is large, upright-
spreading, and productive. Bud hardiness is above average.
The medium-sized fruit is highly colored, attractive, and has firm flesh and fair flavor. The tree
is very productive and requires heavy thinning.
A large attractive, yellow-fleshed peach. The flesh is firm, juicy, of good quality and the stone is
free. The tree is vigorous, productive, and equal to Redhaven in bud hardiness.
A large, attractive, yellow-fleshed peach. The flesh is medium-firm, juicy, and of good flavor. The
stone is free. The tree is very productive, hardy and moderately vigorous.
A medium-to-large, attractive, freestone peach. The flesh is yellow, firm, juicy, and has very good
flavor. The tree is moderately bud hardy.
A medium-large, round, bright-colored freestone. The flesh is yellow and melting. The tree is
more bud hardy than Glohaven.
A large, roundish, mostly red peach with very little fuzz. The flesh is yellow, very firm, and has
very good flavor. The stone is free. The tree is medium in bud hardiness, but is vigorous and pro-
ductive.
The fruit is large, roundish, with 60 percent red on a creamy white ground color. The white
flesh is thick, firm, juicy, smooth, and very good in flavor. The stone is free. The tree is vigorous,
equal to Redhaven in bud hardiness, and very productive.
A large, attractive, highly-colored freestone of very good quality. The tree is large, vigorous,
and productive. Bud hardiness is above average.
A large, highly-colored, yellow-fleshed peach. The flesh is firm, juicy and of good flavor. The
tree is vigorous, productive, and about equal to Redhaven in bud hardiness.
A large, oblate-shaped peach 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, pro-
ductive, and medium in hardiness.
The fruits are large, attractive, and freestone. The flesh is yellow and firm. The trees are vigorous
and productive, and about equal to Redhaven in bud hardiness.
A large, round, highly-colored freestone. The flesh is yellow, firm, and melting. The trees are
vigorous, productive, and are equal to Redhaven in bud hardiness.
A A A ft A A A A A A
■6-
PERFORMANCE OF DISEASE RESISTANT APPLES IN MASSACHUSETTS
Christopher M. Beckerl Daniel R. Cooley,
and William J. Manning3
Department of Plant Pathology,
University of Massachusetts, Amherst
A number of apple cultivars, with immunity to apple scab, and varying
degrees of resistance to rusts, powdery mildew and fireblight, are currently
available from commercial nurseries. As these cultivars have potential use
in apple disease management programs, designed to reduce fungicide usage, we
established a block of disease resistant apple cultivars at the Horticultural
Research Center in the spring of 1978 to determine their performance in Mass-
achusetts. Fruit were harvested in 1982 for the first time.
Eight cultivars were planted. Prima, Priscilla, and Sir Prize were developed
by the Purdue, Rutgers, and Illinois (PRI) Agricultural Experiment Station co-
operative apple breeding program. MacFree and Nova Easy-gro were developed in
Canada and Liberty and NY61345-2 by the New York Agricultural Experiment
Station. Disease-susceptible Imperial Mcintosh was used for comparisons. Trees
were obtained from either the New York State Fruit Testing Cooperative or Stark
Bros. Nurseries.
Cultivars used have been described by their developers as follows:
Prima: 2-1/2 to 3". 60-80% bright red, over yellow ground color.
Rich flavor and crisp texture, with mild subacid flavor.
Flesh, light cream color. Little tendency for fruit to drop
before harvest. Fruit matures 1 month before Red Delicious,
and will retain its flavor for up to 1 month at 34 F. Trees
are spreading and vigorous. Immune to apple scab, susceptible
to cedar apple rust, slightly susceptible to powdery mildew,
and resistant to fire blight. Excellent dessert apple.
Priscilla : 2-1/2 to 3". 75-90% bright red, over yellow ground color..
Crisp texture and pleasant aromatic flavor. Texture and
flavor maintained for 2-3 months at 34 F. 2 weeks before
Delicious (10 days after Prima) . Little tendency for fruit
drop before harvest. Trees are moderately spreading and
vigorous: terminal growth frequently determinate, ending in
a flower bud. Trees and fruit are immune to apple scab,
and resistant to cedar apple rust, and fire blight. Fine
dessert quality.
Sir Prize : 3 to 3-1/2". Yellow, russet free. Ripens with Golden
Delicious (4 weeks after Prima). Juicy flesh, fine grained
texture with thin skir^ that is easily bruised with rough
handling. Waxy skin does not shrivel in storage. Very good
keeping quality through the winter season. Trees are vigorous,
triploid and produce an annual crop. Immune to apple scab,
moderately resistant to cedar apple rust and powdery mildew,
trees have shown little fire blight. Excellent for home
planting or use with direct sales or pick-your-own.
1 9
Disease Management Technician ^ Extension Technician
3 Professor of Plant Pathology
Macfree: 2-3/4", 75% medium to dark lively red, slightly stripped,
over greenish-yellow ground color. Juicy white flesh, sometimes
tinged with green. Slightly course, tough texture, moderate
acidity and firm; pleasant flavor. Ripens a few days before
Red Delicious, Stores 3 months at 32 C. Vigorous spreading
tree: fruit borne throughout. Resistant to apple scab.
Nova Easy-gro : 2-1/2", blushed or stripped medium red over pale greenish-
yellow ground color. Creamy white flesh, firm, crisp, moderately
juicy, subacid; pleasant. Matures with Cortland, keeps well.
Trees are moderately vigorous, and spreading, with fruit borne
throughout the tree. Fruit resistant to apple scab. (Multigenic
resistance from Russian seedling) .
Liberty : 2-3/4", deep bright red, stripped on greenish-yellow ground
color. (Mcintosh parentage easily recognizable.) Flesh pale
yellow, nearly white; crisp, juicy, slightly coarse in texture.
"Sprightly", subacid; browns rapidly upon exposure to air.
Keeps well under refridgeration until January and stores very
well as juice, cider and sauce. Trees are "precocious"; out-
yielded Mcintosh and Red Delicious on similar topworked trees.
Vigorous growth, round topped and spreading: very productive
with fruitbuds terminally and laterally on shoots of current
year's growth and spurs. Immune to apple scab and cedar apple
rust; resistant to powdery mildew and fire blight.
NY 61345-2 : 2-7/8", 90% red blush. Crisp, juicy, slightly coarse; sprightly.
Tree: vigorous and upright. 2 days before Red Delicious. Immune
to apple scab, moderately resistant to cedar apple rust and
powdery mildew.
Standard insecticide sprays were applied from 1978-1982, but no fungicides
were used. Natural inoculum for apple scab and cedar-apple rust was abundant
in all years.
In mid-September, 100 randomly-chosen leaves per tree were evaluated for
per cent apple scab, cedar-apple rust, and frog-eye leaf spot (black rot). Fruit
were evaluated at harvest for scab and other diseases. Results are summarized
in Table 1.
All of the disease resistant cultivars were completely free from fruit
and foliar scab. Imperial Mcintosh, however, had 48.5% foliar and 28.3% fruit
scab. While all the disease resistant cultivars had less foliar cedar-apple
rust than Imperial Mcintosh, Macfree and Sir Prize had more foliar infection
than Nova Easy-gro, NY 61345-1, Priscilla, and Liberty. The original Prima
trees died before 1982. Several younger Prima trees were completely free from
scab, but had extensive cedar-apple rust on leaves. One Prima fruit also had
a rust infection spot. All cultivars had frog-eye leaf spot, with Sir Prize
having the highest incidence. Frog-eye leaf spot on Sir Prize, however, consists
primarily of small purplish flecks, rather than more typical symptoms.
To determine fruit quality. Nova Easy-gro, Liberty, Macfree, NY 61345-2, and
Imperial Mcintosh fruit were harvested and stored at 34 F. in a conventional
cold storage. After one month of storage, fruit were removed, sliced, and
offered to 29 randomly-chosen students, secretaries, faculty and technicians.
Most tasters found little difference between Imperial Mcintosh, Macfree, and
Nova Easy-gro. While all had similar textures Nova Easy-gro, and Macfree were
judged to have slightly less flavor than Imperial Mcintosh. Wi 61345-2 was
generally agreed to be a tasty and slightly tart apple. While not as firm as
Imperial Mcintosh, NY 61345-2 was rated as the first choice of most tasters.
Liberty compared well with Imperial Mcintosh, but was not as sweet and did
not store as well.
When tasters were shown nonlabelled fruit of all the cultivars, all comments
were favorable. More than 80% of the tasters agreed that they would purchase
the fruit if available in roadside stands or in supermarkets.
In 1983, we will be adding the following new cultivars to our planting:
Redfree: Redfree is a medium size (2-3/4") apple with 90% good red
color and smooth, waxy, russet-free skin. Flesh is white,
crisp and juicy. Retains quality for two months or more in
storage. Fruit ripens 3 weeks before Prima and 7 weeks before
Delicious. Immune to scab and cedar rust, moderately resistant
to fire blight and mildew.
Jonaf ree: Closely resembles and matures with Jonathan. Fruits are
2-1/2 to 2-3/4", 75% medium red, with a smooth russet-free
skin. Flesh is pale, crisp, and juicy. Immune to scab and
resistant to fire blight and cedar-apple rust. Moderately
susceptible to mildew. Fruit hangs well to maturity and do
not develop Jonathan spot.
King Luscious : A very large, highly-colored apple with good keeping, eating
and cooking qualities. The skin is a deep red with a beautiful
bloom. The flesh is pure white, with excellent flavor. Season
of ripening is with Rome Beauty and Stayman, although it may
be picked sooner for cooking purposes. The tree is a young
and annual bearer, blooming a week after Rome Beauty, to
make it almost completely frost-proof. The tree is semi-
dwarf in habit, sets it scaffold branches well, and needs
little pruning. Both tree and fruit are resistant to apple
scab. U.S. Plant Patent No, 1994.
Redfree and Jonaf ree are being obtained from Hilltop Nurseries. King
Luscious will come from Bountiful Ridge Nurseries.
All of the trees in the Disease Resistance block will be labelled this
spring by name. Please feel free to examine them when you visit the Horticultural
Research Center. For additional information on disease resistant apple trees,
contact Dr. William J. Manning in the Department of Plant Pathology.
This activity is supported by the Massachusetts Cooperative Extension Service.
Table 1. Performance of young disease resistant apple trees in Massachusetts
in 1982.
% foliar disease
No.
No.
(100
leaves
evaluated/ tree)
trees
Cultivars
Scab
Rust
Frog-eye
fruit
% Scab
2
Macfree
■
18.5
22.5
35
4
Nova Easy-gro
0.5
15.5
16
4
NY 61345-2
0.5
23.3
16
2
Priscilla
4.0
15.0
3
2
Sir Prize
32.0
75.5
3
Liberty
1.3
11.3
35
2
Imp. Mcintosh
48.5
44.0
20.0
19
26.3
-10-
DISEASE MANAGE^fENT FOR APPLES IN MASSACHUSETTS:
1982 RESULTS AND SUMMARY OF THE FIVE-YEAR PROGRAM
Christopher M. Becker,^ Ted R. Bardinelli,2
Daniel R. Cooley,^ Kristin G. Pategas,^and
William J. Manning^
Department of Plant Pathology
University of Massachusetts, Amherst
The five-year pilot program to develop and evaluate new and innovative
apple disease management practices in Massachusetts terminated in 1982. Our
results for 1982 and a summary of the entire program are presented here.
1982 Results
In 1982, 13 commercial apple orchards were involved in the program. Four
followed traditional disease management practices and served as controls for
comparisons. The other 9 were visited by scouts on a regular basis and ap-
plied fungicides to manage apple scab (and other diseases) on a "post-infection"
basis only. Hygro thermographs were used to determine when infection periods
had occurred and when fungicides should be applied. A more complete descrip-
tion of the disease management program can be found in Fruit Notes 46(1) pp. 3-4.
Like many growing seasons in Massachusetts, 1982 was unusual. New green
apple leaves emerged at the same time that mature ascospores of the scab fungus
were available. Two extensive Infection periods occurred in late May with heavy
inoculum released. Primary scab season ended on 4th June. A complete summary
of wetting and infection periods for 1982 is given in Table 1.
Fungicide usage and fruit disease incidence for disease management orch-
ards are given in Table 2. Results for control orchards are In Table 3.
Disease management orchards averaged one less fungicide application. Reduc-
tion in dosage equivalents (2.6 fewer than controls), however, resulted in
savings of $32 per acre for fungicides. Disease management orchards had a
slight increase in per cent diseased fruit at harvest when compared to con-
trols. Savings realized with reduced fungicide costs, however, more than
offset the slight increase in costs due to a few more diseased fruit at
harvest.
Paired t-tests were used to compare results from disease management and
control orchards (Table 4). No significant differences (P = 0.05) were found
between the number of fungicide applications, per cent diseased fruit at har-
vest, and dollar losses from disease. There was a significant difference
between actual fungicide usage, or dosage equivalents, and fungicide costs
per acre. Disease management growers used less fungicide without significant
increases in fruit diseases at harvest.
Variation in the number of fungicide sprays (8-14) and dosage equivalents
(5.67-11.88) in IPM orchards is closely related with both efficiency in timing
of scab sprays, and the necessity for fungicide applications for diseases other
than apple scab, especially the rusts, and powdery mildew. When post- infec-
tion scab sprays were too late to Inhibit apple scab infections, or poor cover-
age was achieved by spraying during windy weather, additional fungicide appli-
llPM Technician 1981-82 ^IFH Technician 1978-80 3Extension Technician
^IPM Scout ^Professor of Plant Pathology
-11-
cations at high rates were necessary to "burn-out" or eradicate scab lesions.
Where rust control was essential, protective sprays were necessary before
all wetting periods (over 4 hours in length) as post-infection applications
of fungicides are not possible for rust management.
Five- Year Summary
A cost/benefit analysis for the five-year program is presented in Table
A. In each year of the program, disease management growers made fewer fungi-
cide applications, with fewer dosage equivalents, and reduced fungicide costs,
compared to control growers. Per cent diseased fruit at harvest in disease
management orchards was either comparable to or only slightly higher than in
control orchards. Disease management benefits per acre were variable, but
always positive for cooperating growers.
When we examined the results for a five-year period, three trends became
evident to us. The first was that disease management benefits are most likely
to occur at a higher dollar level in dry spring seasons, as in 1980, rather
than in wet ones, as in 1982. With fewer wetting periods, greater efficiency
can be achieved in timing post-infection sprays.
The second trend is that continued benefits from disease management de-
crease in magnitude with time. Fungicide sprays and dosage equivalents can-
not be further reduced in number every year. Many control growers have also
begun to adopt disease management practices, obtained from the numerous Ex-
tension education programs we have been involved in over the past five years.
It is becoming increasingly difficult to find control orchards where only
traditional methods are used.
Per cent disease incidence for the five-year period is summarized in
Table 5. Apple scab incidence has been reduced. The trend for calyx end
rots, however, is increasing slightly. Timing sprays only for scab manage-
ment may have increased infection possibilities for end rot fungi before
or after bloom. Using fungicides that are good for scab management may also
mean that they are not as good for end rot management. Anytime a practice
is changed, we can expect that new problems may develop. The use of one or
more sprays of a protective fungicide, rather than a "post-infection" or
"kick-back" material, from tight cluster to petal fall, should eliminate
calyx end rot problems, especially during wet growing seasons.
Acknowledgements :
We have been able to obtain considerable information about apple disease
management during the last five years. We could not have done this without
the enthusiastic and generous support and cooperation of the participating
Massachusetts fruit growers.
This program was supported by special funds from the USDA, by the Massa-
chusetts Cooperative Extension Service, and the Massachusetts Fruit Growers
Association.
12-
Table 1. Wetting and infection periods for the apple scab fungus at the Horticultural
Research Center in Belchertown, MA in 1982
Apple
growth
Wetting Periods
Rain
% Mature
apple scab
Potential
Hour
Duration Mean Temp.
primary-
Date
stage
began
(hrs . )
CF)
(mm)
ascospores
scab infec-
tion
severity
A/17/82
Green tip
20
8
50
17.2
5
None
4/21/82
Green tip
8
5
48
4.5
10
None
4/24/82
1" green
22
8
52
0.01
23
None
4/26/82
1" green
13
24
52
23.5
25
Heavy
4/27/82
Tight cluster
23
12
40
4.6
25
None
5/8/82
Early bloom
24
9
51
0.7
55
None
5/19/82
Petal fall
23
4
67
7.8
55
None
5/22/82
Petal fall
22
58
44
16.1
53
Heavy
5/29/82
Late petal
fall
1
34
56
70.8
50
Heavy
5/30/82
1/4" fruit
24
14
58
0.5
30
Moderate
6/1/82
1/4" fruit
21
15
60
24.5
5
Moderate
*6/4/82
1/4" fruit
17
91
52
93.2
3
Heavy
*End of primary scab season.
13
Table 2. Cost/benefit analysis of fungicide usage and fruit quality in disease
management orchards in 1982
Orchard
% Diseased
fruits at
harvest
$ Loss to
disease per
acre
Number of
fungicide
sprays
Dosage
equivalents
Fungicide
cost per
acre
1
0,1 scab
0.1 end rot
7.70
11
8.26
$ 81.75
2
0.1 scab
0.1 black rot
1.1 end rot
1.1 quince rust
92.40
11
11.76
$122.72
3
0.1 scab
0.2 quince rust
1.8 end rot
80.85
11
10.2
$100.40
4
0.3 scab
0.1 quince rust
2.3 end rot
0.1 black rot
107.80
14
11.88
$113.46
5
0.2 scab
7.70
14
10.32
$121.28
6
0.1 scab
0.1 quince rust
0.1 bitter rot
2.8 end rot
119.35
10
8.80
$ 95.01
7
0.1 scab
19.25
11
8.48
$ 97.14
8
0.4 end rot
15.40
11
9.44
$122.31
9
0.1 end rot
3.85
8
5.67
$ 66.18
Avg.
0.11 scab
1.00 end rot
0.16 quince rust
0.04 other
1.31 TOTAL
50.48
11.20
9.42
$102.25
14
Table 3. Cost/benefit analysis of fungicide usage and fruit quality in control
orchards in 1982
% Diseased
$ Loss to
Number of
Dosage
Fungicide
Orchard
fruits at
disease per
f ungic ide
equivalents
cost per
harvest
acre
sprays
acre
1
12
13.64
$149.10
2
0.10 scab
3.85
12
11.64
$133.44
3
0.60 scab
0.30 end rot
77.00
12
9.81
$106.38
0.10 black rot
4
14
13.0
$148.29
Average . 53
20.21
12.5
12.02
$134.30
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33
Table 6. Cost/benefit analysis of arthropod pest control practices
in IPM vs Check blocks, 1978-1982.
Difference IPM vs
Check
1978
1979
1980^
1981^
1982^
Cost of materials
Oil
Insecticide
Miticide
Aphicide
- $5.81
-$12.51
-$15.83
0.0
+$ 0.23
-$51.64
-$14.59
-$ 0.11
-$ 2.84
-$42.50
-$19.49
-$ 4.30
-$ 2.62
-$37.01
-$16.85
0.0
+$ 1.30
-$51.92
+$ 6.37
+$ 3.33
Cost of pesticide
application
-$ 9.64
-$16,05
-$ 7. 32
-$ 8.96
-$12.18
Value of fruit lost
due to insect injury
-$53.37
-$40.46
-$16.42
+$25.26
-$ 3.85
Avg. net benefit
from IPM
+$97.16
+$122.83
+$93.37
+40.18
+$56.95
Five year average net benefit from IPM +82.10
'1980 data = Complete cooperator blocks.
1981 data = Previous- Year IPM blocks.
1982 data = Complete cooperator IPM blocks
OD
9
C
CI
8
>
7
6
u
u
S
Clt
ID
CD
4
O
Q
J
Figure 1. Trends in Pesticide Usage and Insect Injury to Fruit, 1977-1982.
34
Insecticide Usage
IPM»— — • X - 6.3
CHECK O O X • 8.5
b. Hiticide Usage
CHECK O O ^ ~ ^-^
(8)
(9) (7)
-N.
V-
■^-^
(8)
(16)^
'''(19)-""^
(36)
1
1
(18)
1
—i 1
on
o
a
•77 '78 '79 '80 '81 '82
26Z reduction in IPM Blodcs
-4-
-I-
■+-
'78 '79 '8b '81 '82
54J reduction in IPM Blocks
1 ■■
Total Insect Injury to
Fruit at Harvest
tS '7^ ^iJ ^81
@ 132 reduction in IPM Blocks
Cooperative Extension Service
U.S. Department of Agriculture
University of Massachusetts
Amfierst, Massachusetts 01003
OFFICIAL BUSINESS
PENALTY FOR PRIVATE USE, $300
POSTAGE AND FEES PAID
U.S. DEPARTMENT OF
AGRICULTURE
AGR 101
BULK THIRD CLASS MAIL PERMIT
FRUIT
NOTES
PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES
COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS. UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.
EDITORS
W. J. LORD AND W. J. BRAMLAGE
Vol. 48 No. 2
SPRING ISSUE, 1983
Table of Contents
FRUIT NOTES Subscription Form
Nutritional Problems in 1982 and Suggestions for
Fertilization of Apple Trees in 1983
Effects of Type of Nitrogenous Fertilizer Applied
Under Sturdeespur Delicious Trees on Exchangeable
Elements in the Soil
Preliminary Findings From the Multi-State
Cooperative Apple Interstem Planting
Future of Tree Fruit IPM in Massachusetts
Publication Available
Sampling Soil for Nematodes
Pruning Plum Trees
A Visual Monitoring Trap for the Apple Blotch
Leafminer
Are High Density Strawberries on Ridges For You?
Suggestions for Use of Calcium Sprays in 1983
An Up-date on Calyz-end Rot, and Report of an
Apple Leaf Spot Caused by the Fungus
Sclerotinia sclerotiorum
Use of Promalin to Increase Branching of Young Trees
I Issued by the Cooperative Extension Service, Daniel I. Padberg, Director, in furtherance
I of the Acts of May 8 and June 30, 1914; United States Department of Agriculture and
County Extension Services cooperating. The Cooperative Extension Service offers equal
opportunity in programs and employment.
NIITRTTTONAL PROBLEMS IN 1982
AND SUGGESTIONS FOR FERTILIZATION OF APPLE TREES IN 1983
Wi lliam J . Lord
Department of Plant and Soil Sciences
Prospects for a heavy bloom in 1983 are not too likely follow-
ing the large crop in 1982. However, there are ample flower buds
for a good crop in 1983.
The analysis of leaf samples from commercial orchards showed
that potassium (K) and magnesium (Mg) was deficient in many
orchards in 1982 and boron (B) was generally low. Visual obser-
vations of Mg deficiency were quite prevalent on both apple and
pear trees, which is unusual, and perhaps resulted from leaching
of this element by the heavy rainfall in June (9.6 inches at the
Horticultural Research Center). It is possible that leaching of
K and Mg occurred both from the leaves and soil. Mineral analysis
of Mcintosh fruits from 24 orchards sampled shortly prior to
harvest in 1982 showed that calcium (Ca) levels were low. Two
blocks of trees in each orchard were sampled. Only 5 of the 24
orchards produced fruit in both blocks with Ca levels high enough
to clearly predict that their fruit had a high potential for long-
term storage of good quality fruit.
Information on the Leaf Analysis Reports indicated that some
growers continue to apply a "complete fertilizer". Cost could be
reduced by using fertilizer that contains no phosphorous (P) since
there is no evidence that our apple trees need this element beyond
what is present in the soil.
With the above observations in mind, we present the following
suggestions as a guide for fertilization in 1983.
Nitrogen (N) : Most orchards had a large crop in 1982, there-
fore! the trees may be low in available N for utilization this spring,
We suggest higher rates than normal of N this year unless the trees
were excessively vigorous in 1982 or were heavily pruned this past
winter.
Potassium (K) : Over 901 of the leaf samples were deficient,
probably due to the demand for this element by the large crop, and/or
leaching because of heavy rainfall.
The leaf scorch symptoms of K deficiency may be confused with
the leaf margin burn from calcium chloride sprays. However, unlike
leaf burn from calcium chloride sprays, the scorch of leaf margins
due to K deficiency progresses from the older leaves to the younger
leaves of current season shoots as the season advances. The scorch
may turn gray in color and leaf fall may occur late in the growing
season .
-2-
The K requirements of apple trees with a large crop are high
because the fruit utilizes about 3 times as much K as N. Since
the quantity of K stored by the tree is extremely small, it seems
important to supply adequate K this spring on trees that had heavy
fruit set in 1982.
The requirements of apple trees for K (expressed as K2O), based
on potential yields, are as follows: (a) less than 15 bu: 1.3 lbs.
/tree; (b) 15 to 25 bu: 1.3 to 2.7 lbs/tree; and (c) more than
25 bu: 2.7 to 4.3 lbs/tree. It is necessary, however, to maintain
a balance among the essential nutrients for apple trees. For
example, excessive levels of K can reduce both leaf and fruit Ca.
Therefore, we strongly urge that you participate in our leaf
analysis program to more accurately determine the K needs of your
apple trees .
Calcium CCa) : Our suggestions for meeting the Ca needs of apple
trees can be found in another article in this issue of FRUIT NOTES.
Boron (B) : B can be supplied to apple trees either by foliar
or soil applications. Use the most economical and convenient
method. However, it is safest to apply all elements as a fertilizer
except in emergency situations .
Soil applications of boron should be applied to orchards every
3 years. The rate of application per tree vary with tree age and
size. In low density orchards, apply h pound of borax (11.1°
actual B) or its equivalent under young trees coming into bearing ,
h to 3/4 pound to medium age and size trees and 3/4 to 1 pound to
large or mature trees. Be sure to note the percent actual B in
the fertilizer being used to supply this element . B containing
fertilizers vary from approximately 11 to T\\ actual B.
In medium and high density orchards (115 trees/acre or higher),
it might be best to apply B on an acre basis. We suggest the follow-
ing rates per acre of borax (11.1% actual B) or its equivalent:
(a) trees 4 to 7 years of age - 12 lbs; (b) trees 8 to 15 years of
age - 12 to 24 lbs; and (c) trees 16 to 30 years of age - 24 to
48 lbs.
When the soil application of B is followed by a wet spring,
it may be advisable to apply 2 foliar applications of B the follow-
ing year.
Many growers now rely on annual foliar applications of B. The
usual practice is to add Solubor to the first 2 cover sprays.
Fertilizer grades of borax may contain grit and should not be used
in a sprayer. Mature trees should receive 4 pounds of Solubor per
acre each year. Consequently, the goal is to apply about 2 pounds
per acre in each of the 2 applications. For young orchards, the
addition of 1/2 pound of Solubor per 100 gallons (dilute basis)
to the first 2 cover sprays meets the B requirements of these
trees. Reports of New York State indicate that sprays can be con-
centrated up to 8X with satisfactory results.
Leaf samples from orchards treated with Solubor have indicated
adequate leaf boron levels but the fruit was deficient in this
element . Whether or not B applied as a fertilizer more adequately
meets the B requirement of apples than foliar applied B is not
known by us.
Magnesium (Mg) : Deficiency symptoms of this element are char-
acterized by necrotic (brown) areas between the veins. The older,
basal leaves on shoots and spurs are usually affected first, and
as the season progresses the injury symptoms appear on the younger
leaves. The deficiency symptoms frequently become apparent in
late July and early August. By late summer, the shoots on which
leaves show Mg deficiency may be defoliated except for a few
leaves near their terminals. Mg deficiency increases fruit drop
at harvest.
Weather conditions may have been responsible for the frequent
symptoms last year and the question is what to do if you suspect
or know that you had trees low in Mg. If you have been applying
a dolomitic limestone on a regular basis (dolomitic limestone con-
tains magnesium), no corrective procedures should be necessary.
However, take leaf samples again for analysis in 1983.
If you have not applied dolomitic limestone recently and you
suspect low Mg levels in your trees, we suggest applying this kind
of lime this spring.
Manganese (Mn) : Apple leaves from trees showing Mn deficiency
in 1978 had 12 to 15 ppm of this element which is much below the
desired levels of 30 to 60 ppm. Mn deficiency symptoms are char-
acterized by interveinal fading of chlorophyll with the veins re-
maining green. For those who are unfamiliar with the symptoms of
Mn deficiency, we refer vou to the photograph that appeared in the
May/June 1978 Issue of FRUIT NOTES.
Mn deficiency should be corrected on trees sho\\ring considerable
foliage damage. Although we have no definite proof, Mn deficiency
appeared to be associated with excessive fruit drop on a few trees
in orchard in 1977. Mn deficiency can be corrected by foliar
applications of manganese sulfate or of a fungicide containing Mn.
Apply manganese sulfate at about first cover at the rate of 3 lbs.
per 100 gallons of water. If using a Mn-containing fungicide, 2 or
3 applications are necessary with timings about petal fall, first
and second cover.
-4-
Zinc (,Zn): Based on optimum levels of Zn established by Warren
Stiles7~Cornell University (See FRUIT NOTES 47(2):20-26, 1982] some
of our orchards continue to be low in this element. W. Stiles believes
that apple trees require approximately 2 lbs. of Zn per acre annually
if applied as inorganic salts in dormant sprays or approximately 0.2
to 0.3 lbs. of actual Zn applied as foliar sprays of EDTA chelates
(3 to 5 lbs/acre) .
**********
EFFECTS OF TYPE OF NITROGENOUS FERTILIZER APPLIED UNDER STURDEESPUR
DELICIOUS TREES ON EXCHANGEABLE ELEMENTS IN THE SOIL
William J. Lord, John Baker and Richard A. Damon, Jr.
In a previous issue of FRUIT NOTES (Vol. 45, No. 4), we reported
our findings on the effects of calcium nitrate (Ca(N02)2' amnionium
nitrate (NH.NO^) or potassium nitrate (KNO^) applied annually from
1972 through 1979 on soil pH , the nutrient levels in leaves, on bitter
pit, and fruit calcium (Ca) levels. To briefly review these findings,
neither Ca(N0^)2 nor KNO, affected soil pH , whereas NH-NO^ increased
soil acidity. Nitrogen [N) source had little influenc? on N, potassium
(K) , magnesium (Mg) , or Ca content of leaves, no appreciable influence
on fruit Ca and no effect on the incidence of bitter pit.
Here we present our findings on the effects of N sources applied
annually since 1972 on exchangeable Ca, Mg and K in the soil (Table 1) .
Table 1. Effects of N sources applied annually since 1972 on
exchangeable Ca, Mg and K in the surface 6 inches of soil.
Meq/100 g in soil of:
Treatment
Ca Mg
1978
2
Control
KNOj
NH^NOj
Ca(N02) 2
Control
NH^NOj
Ca(N02)2
6.
, 40ab^
6.
,00b
4,
.04c
7.
,44a
7,
.34a
5,
.36b
2,
. 35a
2
.06a
1
.02b
1
.45b
1981
2
.90a
1
.57b
0.
,26b
1.
,30a
1,
,15a
0.
.98a
0,
.ISb
0,
.73a
8.33a 1.50b 0.77a
z
Untreated soil between trees.
y
Numbers in a column for each year followed by a different letter
are significantly different at odds of 19 to 1.
-5-
In 1978 soil treated with NH^NO^ for 7 consecutive years had
less exchangeable Ca and Mg than untreated soil from between
the trees. In contrast exchangeable Ca was similar in untreated
soil and in soil fertilized with KNO^ or Ca(NO,)^. Soil K was
higher under the trees than between the trees out N source did
not influence K, which had been applied equivalently under all
trees .
the
The
el imi
or
NH^NOj
secut ive
those obt
tially in
our study
tree and
applied i
original experimental design was changed in 1980 with
nation of the KNO, treatment but with the continuation of
i(N0,)2 applications. Our data in 1981 after 10 con-
annual applications of Ca(N0,)2 are in agreement with
ained in 1978 (Table 1) in tnat its use has not substan-
creased the amount of exchangeable Ca in the soil. Thus,
continues to emphasize the difficulty of affecting soil,
fruit Ca when fertilizing with CaCN0,)2 because the amount
s small when it is based on the N needs of the trees.
*******
PRELIMINARY FINDINGS FROM THE MULTI -STATE
COOPERATIVE APPLE INTERSTEM PLANTING-"- ' ^
William J . Lord
Department of Plant and Soil Sciences
The preliminary results from a cooperative interstem plant-
ing established in 10 states in 1976 are published in the Fruit
Varieties Journal, 1982 (Vol. 36, No. 1) and authored by David
Ferree of the Ohio Agricultural Research and Development Center,
Wooster, Ohio. The purpose of this multi-state planting is to
study the growth and yield potential of 2 scion cultivars with
an M9 interstem for dwarfing on 3 vigorous rootstocks under a
diversity of climatic conditions.
Trees for the plantings were propagated by double grafting
a 6-inch stempiece of M9 on scions of Sturdeespur Delicious or
Empire and on rootstocks of MMlll, Ottawa II or Antonovka Seed-
lings. Ottawa II and Antonovka rootstocks were selected because
they provide good anchorage and cold hardiness. MMlll served as
the control. This rootstock has shown good soil adaptability
but lacks precocity when used as the understock on 2-piece trees,
States cooperating in this study were Illinois, Indiana, Iowa,
Kansas, Kentucky, Massachusetts, Michigan, Missouri, Ohio and
Wiscons in.
Editors Note. The trees for the Massachusetts planting were
exceptionally poor, causing tree loss the year of planting, poor
growth of surviving trees and lack of fruitfulness . Other inter-
stem trees were planted on this site in 1979, and no tree loss
has been experienced and growth is vigorous.
■6-
The data from the multi-state plantings, summarized by
Ferree after the first 5-years of study showed that tree losses
occurred at all sites except in Illinois and Iowa. The highest
tree losses were experienced in Massachusetts and Wisconsin.
The losses were attributed to poor tree quality. Trees on the
Kentucky site experienced severe frost heaving in 1978. Regard-
less of rootstock, the growth on the trees was weak in 1979 and
they were removed in 1980.
Tree size based on cross- sectional area was quite variable
among the planting sites. In general, the trees in Illinois,
Iowa, Kansas, Missouri and Ohio were larger than those in Massa-
chusetts, Michigan, Wisconsin and Indiana. Those on the Indiana
site were smallest.
Compilation of the data from the 9 sites indicated that the
trees on MMlll were 15-201 smaller than those on Antonovka seed-
ling or Ottawa II. The trunk circumference and branch spread of
the Empire trees were larger than those of Sturdeespur on com-
parable rootstocks.
The trees were planted with the stempiece 2 inches above
the soil line and the development of root suckers had been of
concern on all sites. Trees on Ottawa II have tended to pro-
duce fewer root suckers than Antonovka or MMlll, particularly in
Kansas, Massachusetts and Ohio. Trees in Missouri and Ohio
produced nearly twice as many suckers as in other states. Of
particular interest in areas where fireblight is of major concern
is the fact that several states observed fireblight strikes on
Antonovka root suckers in 1981 .
The trees produced their first crop in 1979 and the Empire
trees showed the tendency to bear earlier than Sturdeespur Deli-
cious. However, adequate data are yet not available to evaluate
the yield efficiency of the various scion/rootstock combinations.
Ferree summarized the preliminary findings from the multi-
state interstem planting by stating "...it is clear that signi-
ficant differences exist in root suckering potential of vigorous
rootstocks used as root systems for interstem trees. An assoc-
iation also appears to exist between increased suckering and
vigorous scion growth. We have also confirmed that producing inter-
stem trees through double grafting should be avoided because of
poor tree quality and general lack of vigor is considered as a
major factor contributing to poor early tree performance in
several of the test sites".
«« 7b #« «« «
Future of Tree Fruit IPM in Massachusetts
17 7
W.M. Coli , R.J. Prokopy" and W.J. Manning
As we have stated previously, 1982 was the final year of
the Apple IPM pilot program. We anticipate the future of tree
fruit IPM in the state to be two fold:
1) Continued extension involvement - Federal funds for
IPM will continue to come to the state on a formula
basis at least through FY 1983. While no one can accu-
rately predict the level of funding or the security of
such funds given the cost-cutting emphasis of the present
administration, IPM monies are a high priority item in
USDA's budget and appear to be reasonably safe from the
"budget axe."
The 1983 growing season will see the implementation
of IPM programs in cranberries, forage crops, and potatoes,
thereby substantially reducing the amount of USDA money
available for continuing an apple IPM program.
Nonetheless, the Extension administration has ac-
cepted a proposal to continue a part-time IPM Specialist
position at the University for the purpose of maintaining
a scaled-down apple program effort, A major factor in
this decision was the willingness of many large and small
growers throughout the state to pledge their financial
support of such an effort. As of this writing, $3,500
has been pledged by growers, for which we extend our
thanks .
Mr. William Coli will remain in his present capacity
of Tree Fruit IPM Specialist, with additional responsibil-
ities in the area of peach and pear pest management and as
overall coordinator of the multi-crop Massachusetts IPM
program, Mr. Coli will serve as a resource person for
pest management related questions. In addition, he will
continue to take principal responsibility for development
of the twice-weekly insect and disease pest status messages
based on his own scouting in commercial orchards at several
locations as well as on reports from cooperating private
scout/consultants, and regional fruit specialists. As in
the past, apple scab spore maturity information will be
provided by W,J, Manning, Dan Cooley and Chris Becker in
the Department of Plant Pathology.
Extension Pest Management Specialist
2
Extension Entomologist
Extension Plant Pathologist
-8-
2) Private sector implementation - During the course of
tlie apple pilot program, numerous growers have received
IPM training or have assigned some member of their
orchard staff to receive such training. In most cases,
these individuals will be able, with some support from
extension, to continue with an IPM approach on their own.
For other growers, there presently are 3 individuals
offering private IPM scouting/consultant services in the
region. These three, and a fourth person who recently
announced similar plans, all received their initial IPM
training with the Massachusetts apple IPM program and
should provide growers with an excellent choice of avail-
able services.
The individuals we refer to and their addresses are:
Clarence Boston
242 Cayenne Street
West Springfield, MA
David Gordon
51 Pond View Drive
Amherst, MA 01002
(413) 523-5293
Glenn Morin/Dr. Robin Spitko
D.B.A. New England Fruit Consultants
P.O. Box J
Lake Pleasant, MA 01347
(413) 367-9578
PUBLICATION AVAILABLE
The Northeast Regional Agricultural Engineering Service Publi-
cation - 4 entitled "Trickle Irrigation in the Eastern United States"
may be obtained by writing to the Cooperative Plan-Service, Agri-
cultural Engineering Building, University of Massachusetts, Amherst,
MA 01003. There is a $1.50 charge for the publication. Make checks
payable to: Cooperative Extension Activity Fund.
Dr. Donald Elfving, Research Scientist, Simcoe, Ontario referred
to the above publication during his talk on trickle irrigation of
apple trees at the New England Fruit Meetings in January, 1983.
Elfving stated that NRAES-4 is a valuable guide for tree fruit and
small fruit growers interested in trickle irrigation. Information
is presented on advantages and potential problems; plant-soil-water
relationships; system components, specific crop recommendations; system
planning; designing laterals and submains ; preventing line clogging,
and water application calculations.
-9
SAMPLING SOIL FOR NEMATODES
Dr. Richard Rohde
Department of Plant Pathology
University of Massachusetts
The best time to take soil samples for counts of nematode
populations is mid-May through early-July and in mid-September
through October. Nematodes are distributed in clusters
through the field, thus it is important to collect soil from
several areas. For each 5000 sq. ft. area take 10 or more
sub-samples. Samples should be taken at soil depths of 2-10
inches and can be collected with a trowel, spade or soil sampl-
ing tube. On sites sampled prior to planting, obtain the soil
samples where you think the tree rows will be located. When
sampling an established orchard, obtain the soil for nematode
counts from the root zone of the fruit trees. The sample should
also include small roots of the fruit trees since lesion nema-
todes, the most common orchard nematode in our area, is in the
roots during part of its life cycle.
Mix the soil in a bucket and then put 1 quart of the mixed
soil in a plastic container. Samples can be stored in a refrig-
erator for several months but should not be exposed to high
temperatures such as could occur in a plastic bag lying in
direct sunlight or in a car trunk on a hot day. Also, dried-
out soil is useless.
The soil samples for nematode counts should be sent to your
Regional Fruit Specialist, or directly to Dr. Richard Rohde,
Department of Plant Pathology, Fernald Hall, University of
Massachusetts, .Amherst 01003.
********************
PRUNING PLUM TREES
James F. Anderson
Department of Plant and Soil Sciences
There has been an increased interest in the production of
plums in Massachusetts, especially on the part of growers oper-
ating farm markets. Since the apple is the major tree fruit
in Massachusetts, most research and extension activity has been
-10-
dcvotcd to that crop and little attention has been given to tlic
pi uni .
Tlie discussion that follows is offered as a brief guide to
the training and pruning of plum trees.
Training Young Trees
There is a marked difference in the growth habit of plum
trees depending on type and variety. Some are decidedly up-
right while others are distinctly spreading in growth habit.
Regardless of growth habit, most are probably best trained as
a central or modified central leader tree.
The plum tree should have 5 or 6 scaffold branches spaced
about 6 inches apart and spirally around the leader. On upright
growing trees, it would be advisable to spread the branches to
improve the trees structure. Excessively long branches should
be shortened, preferably by cutting it back to an outward grow-
ing lateral. Heading-back cuts may be used when necessary to
shorten and/or stiffen the scaffold branches.
Pruning Bearing Trees
Flower buds are formed laterally on current seasons growth
and on the extension growth of spurs. The flower buds are sim-
ple, containing 1 to 3 flowers, but no leaves. The terminal
bud of both shoots and spurs are leaf buds. European varieties
fruit more heavily from spurs; Japanese types fruit heavily from
both shoots and spurs. The shoot of a Japanese plum is similar
to the peach in flower bud development.
Annual pruning helps to maintain a supply of new wood on
which the flower buds can form. For the Japanese varieties, an
annual shoot growth of 10 to 20 inches for young trees and 10 to
12 inches for older bearing trees is desired. European varie-
ties should average 9 to 18 inches of annual shoot growth for
young trees and 6 to 10 inches for older bearing trees. After a
plum tree begins bearing, an annual thinning out of watersprouts
and branches growing towards the center of the tree will con-
stitute the major part of the pruning operation. The tree should
be kept open to allow for good light penetration, air movement
and spray coverage. Control of brown rot will be much easier if
the tree is prevented from becoming too dense. Keeping the trees
open will also maintain fruiting throughout the lower and inner
portions of the tree. Some heading-back cuts may be necessary to
shorten and/or stiffen the scaffold branches.
Removal of Black Knots
The plum is particularly susceptible to the fungus disease,
black knot, which may be identified in the dormant season by
11
black swellings or cankers on the branches. The principal control
for this disease is to prune off and burn these knots. Remove
small brandies entirely. On larger branches, cut to an outward
growing lateral. In any case, the cut should be made at least
six inches below any evidence of the disease and all diseased wood
should be removed from the orchard. This may necessitate more
drastic pruning than would be recommended ordinarily.
***********
A VISUAL MONITORING TRAP FOR THE APPLE BLOTCH LEAFMINER"^
2 3 4
Thomas Green , William Coli , Geoffrey Hubbell ,
and Ronald Prokopy
Department of Entomology
For the past 3 years, we have attempted to develop a visual
monitoring trap for the apple blotch leafminer, Phyllonorycter
crataegella . This insect, an organophosphate-resistant pest of
apple foliage, is implicated in premature leaf and fruit drop
and reduction in fruit set the following season. A pheromone
trap is available for a related species, P. blancardella (spotted
tentiform leafminer) , but this pheromone is not effective in
attracting P. crataegella , the predominant species in Massa-
chusetts commercial orchards . We theorized that if a visual moni-
toring trap were available for P. crataegella, the need for a
pre-bloom insecticide application against the overwintering gener-
ation adults might be determined from trap capture levels. Here,
we present a brief summary of our research on the development and
utility of a visual trap for P. crataegella .
Results
In 6 experiments , we determined the number of P. crataegella
captured on sticky-coated (=Tangle-Trap^) traps painted with
commercially available paints of various colors. The consistently
highest captures in these experiments were on traps painted with
Sherwin-Williams Tartar Red DarkR Enamel. Results of 2 of the
experiments are presented in Table 1.
1
We wish to express our appreciation to the following IPM field
scouts for assistance with data collection: David Gordon, Kath-
leen Leahv, Joseph Parella, Douglas Roberts, and Roy Zahnleuter
2
Extension Technician
3
Extension Pest Management Specialist
4
Research Assistant
5
Extension Entomologist
-12-
Table 1. Comparison of P. crataegella captures on 20 x 30 centi-
meter* (cm) horizontal ( s t i cky - s i de - up ) traps of various colors
positioned 1.5 meters** (m) above ground in the interior part
of the tree canopy.
Experiment
1
Experiment
2
Color
Avi
erag(
2 number
Color
Avi
erage number
of
P.
crataegella
of
P.
crataegella
trap
per
trap
trap
per
trap
Red
610
Red
1580
Green
548
Green
1267
Orange
500
Light
Gray
1200
Gray
486
Black
1141
Foil
470
White
1126
White
467
Medium
Gray
1113
Yellow
447
Dark G
ray
976
Blue
411
Clear
368
Black
356
One centimeter = 2.54 inches
One meter = 39.37 inches
The next step in the development and utilization of a visual
trap was to evaluate the influence of the orientation of the trap
on its effectiveness in capturing P. crataegella . The orientations
tested were: (1) horizontal, sticky-side-up ; (2) horizontal, sticky-
side-down; (3) vertical; (4) 90 degree (tent- shaped) , sticky-side-
up; and (5) 90 degree (V-shaped), sticky-side down. Captures were
higher on the horizontal, sticky-side-up traps than on those with
the vertical or sticky-side-down orientations (Table 2).
Table 2. Comparison of P. crataegella captures on 20 x 30 cm red
traps of various orientations, positioned 1.5m above ground
in the interior part of the tree canopy.
Orientation of trap Average number P. crataegella per trap
Horizontal, sticky-
side-up 131
90° (tent-shaped) ,
sticky-side-up 85
Vertical 12
90° (V-shaped) ,
sticky-side-down 10
Horizontal ,
St icky- side-down 5
13-
on horizontal
positions within
block of semi-
iameter. The in-tree
alfway between the
alfway between the
top, halfway between
ove ground, . 5 m
ground, 0.5 m in
he trunk and 1.5m
st leafminers (Table
Table 3. Comparison of P. crataegella captures on 20 x 30 cm
horizontal red traps ( s t i cky - s i de - up ) at various positions
within the tree.
We then
compared P,
. crataegella
captures
(sticky-side-
up) red traps placed at
various
the tree. Th
lis ex
periment was conducted in
a
dwarf trees,
ca. 5
m in
height and 4
.5
m in
d
positionings
were :
(1)
0.5 m above
ground ,
h
trunk and dri
pline
; (2)
1.5m above ;
ground.
h
trunk and dri
.pline
; (3)
0.5m below
the tree
the trunk and
[ outermost
foliage; (4)
1,
. 5 m a
lb
out from the
tree
trunk ;
; and (5) 1.5
m
above
i
from the drip
• line .
Traps placed 0.5
m
from
t
above the ground (
position 4) captured
the mo
3).
Position of trap
Average number P. crataegella per trap
1.5m height ,
0.5 m out from trunk
1.5m height ,
halfway between
dripline and trunk
0.5 m height ,
halfway between
dripline and trunk
1.5m height ,
0.5 m in from dripline
0.5 m from tree top,
halfway between trunk
and outermost foliage
161
125
96
87
11
In the spring of 1982, the red horizontal (sticky- side-up)
traps were used in 21 IPM orchard blocks in Massachusetts. The
traps were placed 1.5 m above the ground and ca. halfway between
the tree trunk and dripline. Each week, as part of the regular
field scouting routine, leafminer adults were counted and removed
from the traps, and foliage was sampled to determine the average
number of mines per leaf. Cumulative average trop captures were
highly positively correlated with the number of mines per leaf
in the 21 blocks sampled. Figure 1 represents a regression of
mines per leaf on trap captures through 2 weeks after petal fall and
illustrates a prediction of 0.13 mines per leaf (the first gener-
ation Economic Injury Level for stressed trees) at a cumulative
average of 12 P. crataegella per trap.
14-
Conclusions
Sticky-coated, 20 x 30 centimeter red traps, hung at
height inside the canopy o£ apple trees, were effective fo
itoring P. crataegella adults. We recommend that the trap
at a rate of 1 per 0.8-1.2 hectares*, and that a pesticide
(oxamyl or fenvalerate) against the adults be applied befo
white shows on the flower petals if cumulative pre-bloom c
(from silver-tip through late pink) reach or exceed 6 adul
trap. This tentative action threshold is conservative, al
for both the reproductive potential of P. crataegella and
stress due to drought, calcium chloride burn, and/or mite
Additional work is planned for the 1983 season to further
this threshold and to develop an additional action thresho
unstressed trees. This trap should be valuable in reducin
need to wait until first generation mines appear before a
spray decision can be accurately made.
chest
r mon-
s be used
treatment
re any
aptures
ts per
lowing
for tree
injury,
validate
Id for
g the
leafminer
0.6r
0.5 -
0.4 -
AVG
MINES
PER
LEAFo.3
0.2
0.1
O ^
15
45 60 75
NO. LM PER TRAP
H.
00 211
Figure 1. Regression of first generation mines per leaf on
visual trap captures in 21 commercial orchard blocks
One hectare = 2.471 acres
-15-
ARE HIGH DHNSriY STRAIVRERRIES ON RIDGES FOR YOU?
Dominic A. Marini
Regional Fruit and Vegetable Specialist
Plymouth Countv Extension Service
Hanson', MA 02341
High density systems with up to 58,000 plants per acre
planted three inches apart on ridges 8 to 12 inches high and 3
feet apart are presently receiving a great deal of attention.
Yields of up to 45,000 quarts per acre are reported; and many
grovvers are wondering if they should adopt this system. Here
are a few things to consider in arriving at a decision.
Is your soil suited to the ridge system? A fairly level,
well-drained site is a necessity. Breaking up the soil to a
depth of 16 to 18 inches vvfith a subsoiler, followed by deep
plowing, 10 to 12 inches deep, is practiced by growers who use
the system successfully. Specialized, expensive equipment is
needed for leveling the soil and constructing the ridges.
Soil fumigation is recommended for any system of growing
strawberries. It is essential to prevent losses from black
root rot and other soil-borne diseases in order to obtain the
high yields possible with this system. Overhead irrigation for
frost protection and to maintain ample soil moisture is also
recommended for all growers, but is more essential for the
ridge system since the ridges dry out much faster than level
beds. More frequent nitrogen fertilization is necessary with
the ridge system because of the leaching of nitrogen resulting
from irrigating more often. And greater attention to insect,
disease and weed control, and winter protection must be given in
order to obtain high yields. Maintaining the winter mulch is
more difficult because of the sloping sides of the ridges.
Extremely high yields are possible with the high density
ridge system of growing strawberries for large scale, top notch,
specialist strawberry growers with the proper site and soil
conditions. For the average grower operating on a small scale,
growing a variety of crops on hilly, rocky. New England soils,
such yields are not very likely. Most growers are probably bet-
ter off with the more conventional systems of matted row or
some sort of spaced runner system on 4 to 6 inch high raised
beds .
AAA*****
-16-
SUHGESTIONS FOR USE OF CALCIUM SPRAYS IN 1983
Mack Drake and William J. Bramlage
Department of Plant and Soil Sciences
Calcium chloride fCaCl-,) foliar sprays are recommended in
Massachusetts for all apple growers to increase the flesh calcium
(Ca) content. Higher flesh Ca can markedly reduce bitter pit,
cork spot and fruit breakdown during storage.
Apply foliar sprays of CaCl2, beginning 3 weeks after petal
fall and repeat at 2 week intervals totaling 6 to 8 applications.
Apply 6 pounds CaCl2 per acre per spray until mid-July. After mid-
July apply 8-10 pounds per acre per spray. Continue foliar CaCl2
until fruit are ready for harvest. Use a technical grade of CaCi-;,
such as Allied Chemical Dow Plake, 77-801 CaCl^. Other brands may
be equally suitable.
Experience in Massachusetts has shown that CaCl^ can be com-
bined with pesticide sprays. However, some growers nave observed
that the combination of Captan or Guthion (azinphos methyl) 50 WP
and CaCl^ may increase foliar burn. DO NOT MIX CaCl^ AND SOLUBOR
SPRAYS! ALWAYS DISSOLVE CaCl2 IN A PAIL OF WATER and add this
last, when the spray tank is nearly full, to insure that the CaCl2
is completely dissolved before spraying begins.
Foliar CaCl2 sprays may be applied as dilute (300 gallons/acre)
or up to lOX concentration (30 gallons/acre). In our research,
apple flesh Ca was increased more by concentrated than by dilute
sprays .
CaCl2 sprays can cause burn of leaf margins. Foliar injury
has been more serious on Mcintosh than on Delicious or Cortland.
Apple leaves are less susceptible to CaCl-, burn after mid-July.
Mcintosh growing on M7 may be more susceptible to foliar burn than
those on standard rootstock. Weak or injured trees may be more
susceptible to CaCl^ burn than healthv trees" To reduce the chance
of leaf burn, DO NOT REPEAT A FOLIAR CaCl^ SPRAY UNLESS ONE-HALF TO
ONE INCH OF RAIN HAS FALLEN SINCE THE LAST APPLICATION'.'
In 1982, 3 different materials were compared as suppliers of
foliar Ca at the University of Massachusetts Horticultural Research
Center. One was commercial CaCl^; the second was a proprietary
formulation of CaCl^; and the thnrd was a chelated Ca compound.
Rate of application^was 86 grams Ca per tree in a total of 8 appli-
cations. Fruit Ca was 115, 165, 155 and 158 parts per million
respectively, for control, CaCl2, Formulation 1 and Formulation 2;
the amount of the breakdown was 33, 7, 7 and 11 percent, respectively,
for fruit air stored at 32°F for 5 months and then held at 74°F for
7 days. These results agree with those of previous years, and show
-17'
the positive effect of increased fruit Ca in reducing storage
breakdown of Massachusetts-grown Mcintosh apples. We do not
recommend long term storage of Mcintosh apples with less than
150 ppm flesh Ca.
Questions have been asked about possible accumulations of
chloride (CI) in the soil. Chloride salts are highly soluble.
Research in the Netherlands showed that there was no annual build-
up or accumulation of chloride where annual rainfall exceeded
30 inches per year. Rainfall in all areas of Massachusetts
exceeds 30 inches per year.
Annual application of muriate of potash (potassium chloride)
for corn silage, vegetable crops and alfalfa in Massachusetts
usually exceeds 200 pounds per acre, supplying about 100 pounds
of chloride per acre. Only 35 pounds of chloride are applied
per acre when our recommendations for foliar CaCl-, sprays are
followed. Also, it is important to note that this 35 pounds of
chloride is applied in 6 to 8 increments of 4 to 6 pounds per acre
foliar application as compared to the 100 pounds of chloride in
one application for corn, vegetables and alfalfa.
WARNING : The initial pH of commercial CaCl^ in water is 10.3,
since small amounts of free CaO form Ca(OH) in water. There is
evidence that the high pH may reduce effectiveness of some pesti-
cides. It is therefore recommended that 2 quarts of 5% vinegar
be added per 100 pounds of CaCl2 to neutralize the excess (OH)
and bring the reaction of the spray solution to about pH 6.0.
**********
AN UPDATE ON CALYX- END ROT, AND REPORT OF AN
APPLE LEAF SPOT CAUSED BY THE FUNGUS
SCLEROTINIA SCLEROTIORUM
12 3
Christopher M. Becker , Daniel R. Cooley and William J. Manning
Department of Plant Pathology
Calyx-end rot of apple, caused by the fungus Sclerotinia
sclerotiorum , has been observed in Massachusetts orchards in recent
years. A report on fruit symptoms and losses in 1980 was published
in FRUIT NOTES 46(1) :l-3. During the 1982 growing season, calyx-
end rot was again prevalent in many Massachusetts orchards. S.
sclerotiorum was also found to cause a previously unreported leaf
spot .
1
Research Assistant
2
Extension Technician
3
Professor of Plant Pathology
-17a-
ADDENDUM
After this issue of FRUIT NOTES had gone to press, it came to
our attention that the recommendations for use of CaCl2 appear to
be in conflict with statements in the "Annual March Message to Massa-
chusetts Fruit Growers (1983)", issued by Ronald Prokopy, William
Coli and Thomas Green of the Department of Entomology. To avoid
confusion from "mixed messages", the following additional comments
are presented:
Beginning about 1975, in Massachusetts we recommended separating
the applications of CaCl2 and pesticides. However, for the past 5
years many Massachusetts growers have combined CaCl^ with pesticide
sprays without observed reduction in effectiveness of pesticides.
Nevertheless, as we warn on page 17, addition of CaCl2 can signifi-
cantly raise the pH of the spray solution, which theoretically can
reduce the effectiveness of the pesticides.
This past year. Dr. George Greene conducted experiments at Big-
lerville, PA which showed that while CaCl^ raised the pH of water
it caused no measurable increase in disease or insect damage to apples
when combined with the pesticides he was using. It should be noted,
however, that some other researchers have reported evidence of reduced
effectiveness of pesticides at these high pH ' s .
In 1982 a number of Massachusetts growers added vinegar to lower
the solution to about pH 6, as recommended on page 17, to their mix-
ture of CaCl2 and pesticides. There was no dissatisfaction with
results .
Nevertheless, since some researchers and some states have issued
warnings of possible ineffectiveness of vinegar as a remedy, the
following additional steps can be taken if a grower feels that they
are necessary .
1. Use CaCl^ of a higher purity grade. Technical grade (77-
80l)CaCl2 will affect pH somewhat more than high purity
grade materials. However, the higher purity grade is
much more expensive and less available.
2. Apply CaCl2 sprays separately from pesticides.
3. Use a commercial buffer rather than vinegar to lower the
pH. Some concerns have been published that acetic acid,
the chief component of vinegar, may not be stable over
long periods in the spray mixture. However, it should
also be noted that some commercial buffers may cause Ca
to precipitate from solution, thereby reducing the value
of the CaCl2 sprays.
It should be recognized that we are not recommending the above
steps. We are alerting growers to concerns that have been raised
elsewhere, and to steps that can be taken if they feel that these
concerns warrant extra precautions.
William J. Bramlage, William Coli and Mack Drake
18-
the
man-
an
Fig. 1. Developing Mcintosh fruit
with calyx-end rot.
In mid-June, 2-81 of the Mcintosh fruit observed in 8 of
10 orchards visited by disease management scouts, were developing
calyx-end rots CFig« 1) •
Delicious, Cortland, and
Macoun also had end rots,
but at lower rates. Most
infected fruits ripened
prematurely, or dropped
by mid-August. Despite
premature drop, disease
agement scouts recorded
average of 1.001 infected
fruit in 10 orchards dur-
ing a harvest survey
CFRUIT NOTES 48(1) :11) .
All orchards with
calyx-end rotted fruit
in mid-June developed a
previously undescribed
leaf spot. Spots were
1-3 cm in diameter,
light brown, and vis-
ible on both sides of
the leaf (Fig. 2) .
These lesions were not
bound by veins. Some
lesions were noticed
next to non-pollinated,
wilted blossoms, and
several lesions had
developed following
contact with young end
rotted- fruit . Numerous
other spots contained
an antherl in the center
of the lesion. Infected
leaves seldom had more
than one spot per leaf,
with lesions typically
larger than frog^eye
leaf spot (caused by
Physalospora obtusa ) or
"captan spot". In con-
trast to typical frog-
eye leaf spot, the
Sclerotinia lesions
were an even than with-
out concentric darkened
areas. Most infected
leaves turned yellow
Fig
Mcintosh leaf with
tinia leaf spot.
Sclero-
from an apple blossom
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within several weeks and dropped by mid-July to mid-August.
Isolations from the center or edge of these foliar infections
onto sterile petri plates of potato carrot agar consistently
yielded the fungus Sclerotinia sclerotiorum . This was the first
reported isolation of the fungus from apple foliage. Controlled
laboratory studies were conducted to determine the conditions
necessary for foliar infection by S. sclerotiorum . Results
showed that not only would the fungus infect wounded leaves , but
that unwounded leaves developed lesions providing that continuous
moisture was present.
The life cycle of Sclerotinia sclerotiorum is well known on
beans, lettuce and many other vegetable crops. However, to date
no successful studies have been done on how the fungus infects
apples. It is presently believed that spores, released during
spring rains, infect blossoms. It is further thought that pro-
longed wet weather encourages the fungus to continue growth into
developing fruit with an end rot resulting. It is likely that
foliage infections occurred directly from spores, or following
contact with young fruit infected with S. sclerotiorum . It may
be possible that fungal spores are present on anthers or pollen
grains, thus, explaining many of the foliar infections described
above.
At this time, the fungus does not seem to present an economic
threat to apple foliage. However, end rots have been increasing
during the past 3 years (FRUIT NOTES 48 (1) : 10- 16) . Current apple
scab fungicide programs may not provide adequate control of calyx-
end rots and no fungicides are currently registered for the disease
When prolonged infection periods exist between pink and first
cover, applications of captan and benomyl may be helpful.
In attempts to gain more information about the disease on
apples, the Department of Plant Pathology hopes to monitor develop-
ment of Sclerotinia sclerotiorum under controlled conditions in the
field next season.
**********
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USE OF PROMALIN TO INCREASE BRANCHING OF YOUNG TREES
Duane W. Greene
Department of Plant and Soi