Full text of "Fruit notes"

DnnDDnnaDnDnnnnDDanDnnDDnnDD

a -«™^

□ 8

g UNIVERSITY LIBRARY 9

H □

□ UNivERsrry of Massachusetts n

D UBRARY 9

n AT D

□ AMHERST g

n D

D °

g 8ia.OGICAl D

□ p

□ ft - Ti 1 ■- - - - Q

9 ArRi--*^._j n

□ n
ci D

g SCIENCES LIBRARY B

n □

□ D
D p

□ p
a p

□ ^— — ^-^■^— — — i^ p

□aDnnannnnnnnDnnnpnDDDnpnnnp

Fruit Notes

Prepared by the Depeirtment 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 58, Number 1
WINTER ISSUE, 1993

Table of Contents

Peach Pests III: Diseases of Fruit and Foliage

Peach Pests IV: Diseases of Peach Wood

Apple Maggot Fly Behavior: Probability of Fly Capture
on Red Sticky Spheres in Relation to Fly Age and Maturity

Evaluation of Four Rootstocks and Two Mcintosh Strains

Do Overwintering Red Mite Eggs Portend Summer Mite Troubles?

Evaluation of Red Coloring Strains of Gala Apple

Spiders in Second-level and First-level Apple IPM Blocks

Apple Integrated Pest Management in 1992:
Insects and Mites in Second-level Orchard Blocks

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 $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 this publication are contiDgcnt 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
stale 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,
conctTning the use of these products. USER ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY
DAMAGE.

Issued by the University cf Massachusetts Cooperative Extension System, Robert G. Helgesen, Director, in
furtherance cf the acts of May 8 and June 30, 1914. The University of Massachusetts Cooperative Extension System
t^ers equal opportunity in programs and employment.

Peach Pests III: Diseases of Fruit
and Foliage

Karen I. Hauschild

University of Massachusetts Cooperative Extension System

In "Peach Pests I" and "II," I discussed insect
and mite pests of peach finiit, foUage, and wood.
In this article I will focus on the diseases of peach
fiiiit and foUage.

There are several frequently observed dis-
ease problems of peach fruit in Massachusetts.
The most common of these is brown rot; how-
ever, peach scab and bacterial spot also can be
troublesome. X-disease and peach leaf curl are
the most frequently encountered foliar disease
problems.

Below is a brief description of each of these
problems and basic information on non-chemi-
cal control measures.

Brown Rot

Brown rot of peaches is caused primarily by
Monilia fructicola (Wint. ) [There is another spe-
cies oiMonilia, M. laxa (Aderh. & Rhul.) which
normally is associated with almond, apricot, or
tart cherry.] M. fructicola is a fungus that over-
winters in mummified fruit, or in infected flow-
ers or twigs. As frviit buds open in the spring,
smaU apothecia (cup-shaped mushroom-like
fruiting bodies) develop from mummied fruit.
Development is favored by adequate moistin*e
and temperatures between 63 and 68°F. Within
each apothecium, asci bearing 8 ascospores each
are produced. When moisture hits these asci, the
ascospores are ejected and carried by wind to
peach blossoms where they cause infections.
The most susceptible flower part is the pistil.

Brown rot infections also can occur when
conidia arise either from cankers on the tree or
from the surface of fruit mummies. Spores from
these conidia are carried by wind or rain to
susceptible peach flowers. (For conidia to form,
relative humidity must be 85% or higher.) In-
fected blossoms brown and wither but remain

attached to twigs.

During summer months, brown rot activity
decreases, but increases again as fruit begins to
mature. Conidia produced on infected blossoms
or on green fruit usually are the source of infec-
tion for fruit at harvest. Fruit infection can occvir
directly through the fruit cuticle, through natu-
ral openings on the fruit, or, most readily,
through wounds. Warm, wet weather favors
brown rot infections. Under optimum conditions
for the fungus, mature fruit can decay in a
matter of hours. Initial infections on fruit ap-
pear as brown, dry blotches that spread rapidly
over the finiit. Spores are produced 6x)m these
blotches, resulting in grey fiizz. Handling in-
fected fruit also can spread the disease to
uninfected fruits.

Removing infected and mummified firuits
can reduce disease inoculum levels. Mowing in
late fall also helps reduce inoculum. Removal of
twigs infected with blossom blight helps control
future brown rot infections. Fungicides apphed
at bloom and before moistiire forms on the
surface of maturing fruits help prevent brown
rot infections.

Peach Scab

Peach scab is an occasional problem locally,
but is more prevalent in warmer peach growing
areas than here. Peach scab is caused by a
fungus, Cladosporium carpophilum, that over-
winters on twig lesions. Conidia are produced
from these lesions in the spring and they infect
peach fi-uit a few weeks after petal fall. Forty to
70 days after an infection has occurred small,
greenish circular spots appear on fruit surfaces,
especially near the stem end. As lesions age,
they become velvety (like apple scab) and black.
If infections are severe, the lesions coalesce.

Fruit Notes, Winter, 1993

resulting in abnormal finiit growth and fixiit
cracking.

Pruning to facilitate good air circulation
within trees helps to control peach scab. Fungi-
cides applied to control brown rot usually also
are efifective against peach scab. Peach scab
generally is more prevalent when warm, wet
weather occurs just after shuck split.

Bacterial Spot

Bacterial spot, caused by the bacterium
Xanthomonas pruni, can infect leaves, shoots,
and fruit of peaches, apricots, and nectarines. In
the spring, bacteria oozing out of overwintering
cankers are carried by water droplets to young
fruit leaves or shoots. Moisture in fog or dew is
sufficient to spread the bacteria. Heavy rain
spreads the disease even further. Frequent
rains accompanied by moderate temperatures
and high winds also encourage infections, espe-
cially during the months of June and July.

Leaf lesions are small and angular, appear-
ing first as water-soaked spots and then turning
brown to black. Centers of these spots often fall
out, leaving reddish colored margins. Lesions
generally are more severe at the tips of leaves.
Leaves that are severely infected turn yellow
and drop. Early season infections on fruit de-
velop into cracks. Lesions are not confined to the
friait surface, but rather go deep into the frijit
flesh.

Non-chemical controls for bacterial spot in-
clude the use of resistant cultivars such as
Redhaven, Loring, Sunhaven, Jefferson, and
Madison. Excessive use of nitrogen may aggra-
vate bacterial spot problems.

to leaf tissue and infection then can occur. Leaf
curl is most severe during cool, wet weather,
particularly at temperatures between 50 and
70°F. Peach trees are susceptible only during
the short period of bud swell to bud opening.
Symptoms appear about two weeks after leaf
emergence. Small, reddish areas develop on
small leaves. As the disease infection
progresses, the leaf wrinkles and puckers in
small areas or along the entire leaf. The m^'or-
ity of infected leaves drop. The fungus produces
ascospores which spend the summer on the
peach tree, but then produce overwintering bud
conidia.

Where leaf curl is severe, maintain tree vigor
by: 1) thinning fruit, 2) irrigating during periods
of drought, and 3) fertilizing by mid-June. A
dormant spray of a copper-containing fungicide
after leaf drop or before bud swell usually will
control leaf curl.

A recent study conducted by L. Burkham
("Alternatives for ControlHng Peach Leaf Curl"
appearing in Common Sense Pest Control Quar-
terly) found that organic growers in California
were able to control peach leaf curl by sprajdng
a seaweed fertiUzer once a month. Speculation
is that susceptibility to leaf curl may be related
to magnesium deficiency. Seaweed contains a
high level of this element.

Also, numerous nectarine and peach culti-
vars have been evaluated for susceptibility to
leaf cin-1. (Scorza, R. 1992. Evaluation of foreign
peach and nectarine introductions. Fruit Variet-
ies Journal 46: 141-144). All of the North Ameri-
can cultivars mentioned in this study (Harbelle,
Elberta, Redhaven, ReUance, Loring, and Sun-
Ught) showed varying degrees of susceptibility.

Peach Leaf Curl

Peach leaf curl is caused by the fungus
Taphrina deformans. Spores of the leaf curl
fungus are very resistant to adverse weather
and can remain dormant on twig surfaces for
two years or longer. Overwintering spores are
washed to the surfaces of leaf buds by spring
rains. These spores then multiply during wet
weather until leaf bud scales open. Once bud
scales become loose, spores are carried by water

X-disease

X-disease is caused by a virus-like organism
known as a mycoplasma. Leafhoppers carry the
disease from infected chokecherries or peaches
to other peach, nectarine, or cherry trees. Once
in the trees, mycoplasmas live in phloem cells, a
type of vascular conducting cell.

Symptoms of x-disease are leaf yellowing or
reddening with shot-holing appearing during
July and August. Affected leaves drop, leaving

Fruit Notes, Winter, 1993

"tufts" of green leaves at ends of twigs. As the
disease progresses through the tree, Umbs die
back and each year more of the tree becomes
infected. Fruit on infected trees at first appear
normal, but they most often drop prematurely.

Young trees infected with x-disease should
be removed and destroyed. In older trees, re-
moving infected Umbs may slow the spread of
the mycoplasmas; but once x-disease has
started, it is difficult to control. Antibiotic
therapy may help also.

Removing chokecherries near peach or-
chards is essential.

For additional information on any of these
pests, please refer to:

Jones, A.L. 1976. Diseases of Tree Fruits. (Cooperative
Extension Services of the Northeast States. NE 96.

LaRue, J.H. and RS. Johnson (eds.). 1989. Peaches,
Plums, and Nectarines: Growing and Handling for
Fresh Market. Cooperative Extension, University of
California. No. 331.

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 En-
gland. University of Massachusetts Cooperative Ex-
tension System Circular C-159 R 1991-2.

^% •10 •i^ ^L0 ^|V

#J% rfi rf» •Y* •?•

Peach Pests IV: Diseases of
Peach Wood

Karen I. Hauschild

University of Massachusetts Cooperative Extension System

This is the last in a series of four articles
describing major insect and disease pests of
peaches in Massachusetts. In this article I wiU
describe diseases that attack peach wood, pri-
marily canker diseases.

In general canker diseases occur where
peach trees are stressed due to drought, poor
growing conditions, cold temperature, or poor
pruning. Healthy, vigorous trees are less sus-
ceptible to attack by canker diseases. Several
disease organisms cause canker formation on
peaches. Following are brief descriptions of the
major causal agents of perennial cankers found
on peaches and nectarines in Massachusetts
orchards.

Cytospora (Valsa) Canker

Two species oiCytospora are associated with
peach canker - C. leucostomia Saac. and C.

cincta Saac. Cytospora overwinter in cankers or
on dead peach wood. Bumps containing pyc-
nidia with small conidia are produced under
bark. These pycnidia grow through the bark and
expose spores to rain. Splashing rain or rain
driven by heavy winds spread conidia to other
infection sites on damaged or injured bark.
Canker growth is related to temperature and
growth habit of the peach tree itself C. cincta is
most active during spring and fall at tempera-
tures between 60 and 75°F. C. leucostomia is
more active at temperatures between 86 and
91°F, that is, during the summer months. Can-
ker development can occur in one of three ways.
First, cankers may extend down limbs toward
tree trunks, with Umb death occiirring at the
rate of one or two Umbs per year over a period of
several years until the entire tree eventually is
killed. This pattern is the classic "perennial

Fruit Notes, Winter, 1993

canker syndrome." Second, cankers may de-
velop in twigs, small branches, or around prun-
ing cuts but remain localized. This type of
canker generally results in only minor damage
to the tree. Third, trees may leaf out normally,
followed by sudden wilting and total tree death.
In cases like this the tree usually is severely
damaged by cold temperatures and the trunk
and lower scaffold Umbs quickly are colonized by
Cytospora. Again, tree health and environmen-
tal factors play a major role in the severity of
Cytospora.

Since both species of Cytospora reqmre a
wound or natural opening to infect peach trees,
proper priming and pest management practices
help prevent serious infections. Pruning in fall
or early winter can contribute to Cytospora
infections because pruning cuts made at these
times do not heal as quickly as those made in the
spring.

For injured or weak trees, there are no
chemical control measures for Cytospora that
have proven completely successful, partly be-
cause spores can be released throughout the
year. If only a few cankers are present, remov-
ing and destroying infected branches below any
sign of disease can be helpful. Do not plant new
pe ach orchards on poor si tes . Do not prune in the
fall or early winter. Additional measures that
will help prevent Cytospora canker infections
include the following:

1. fertiUze trees early in the spring to avoid late
growth spurts;

2. avoid mechanical injury to trees;

3. apply a fungicide spray after pruning, but
before a rain;

4. avoid weak crotch angles; and

5. whitewash southwest sides of trees and
lower limbs (this practice can help prevent
injury due to cold temperatures).

Brown Rot

As mentioned in "Peach Pest III," brown rot,
Monilia fructicola, can infect twigs. When the
fungus moves into woody tissues it causes the
development of small CEinkers. Cankers, as they
grow, can girdle twigs eventually, resulting in
withering and death of terminal growth. Gum-

mosis often accompanies spur blight and canker
formation.

Cankers caused by brown rot may develop as
a result of blossom blight or may move down
from the finiit pedicel into a twig or larger
branch. On twigs or small branches, brown rot
cankers normally are eUiptical, well-defined,
and brown. During wet weather, gummosis
appears, followed or accompanied by tufts of
grey spores. Cankers on larger branches caused
by rotted fruit appear (similar to those described
above, but likely to be much more severe and
eventually kill the infected branch). In the year
following severe canker development, leaves
above the girdling cankers first appear normal
then later turn yellow, wilt, and eventually die.

Phytophthora Root and Crown Rot

Crown rot does not appear to be a serious
problem in Massachusetts peach orchards, but a
brief description is given below.

Waterlogged soil, air temperature, plant
nutrient status, species of Phytophthora in-
volved, and susceptibility of host tissue all play
roles in the occurrence and severity of
Phytophthora infections. Most infections occur
during the spring, summer and fall months and
are spread by infected plants, soil, or water.
Infections that occur in crowns or larger roots
(especially of yoimg trees) spread rapidly, oft^n
killing trees in one or two seasons. Infected trees
may appear healthy in the fall, leaf out normally
in the spring, but then collapse when warmer
temperatures occur. Symptoms of infection
vary fi-om withered, bright rust-colored leaves
on severely infected trees to decreased overall
growth and smaller, yellow leaves on trees that
show slower decline. Infected roots or crowns
show reddish-brown necrosis of bark and outer
wood with a distinct, layered margin; however,
after some time roots decay and turn grey-black.

Avoiding waterlogged soils, proper schedul-
ing of irrigation, and proper planting practices
help prevent Phytophthora infections from oc-
curring and becoming severe.

Bacterial Canker

Bacterial canker, caused by either Pseudo-

Fruit Notes, Winter, 1993

monas syrincae or P. morsprunorium, is thought
to be an increasing problem in Massachusetts
peach orchards. Damage by Pseudomonas var-
ies among types of host fruit. On peaches, leaf
and flower buds fail to open in the spring and are
thought to have been infected during winter
months. Or, in other instances, infected spurs
show normal growth in the spring but collapse
during sunmier months, turning into wilted
leaves and dried-up fruit. If infection occurs
annually, trees lose bearing surface.

Bacteria overwinter in infected buds or can-

kers. Spring rains wash bacteria to unfolding
plant tissue. Frost-injvired leaves and blossoms
are thought to be more susceptible to Pseudo-
monas infection. Periods of cool, rainy weather
foster early-season infections and disease
spread. Disease spread also occurs under simi-
lar weather conditions in the fall.

Canker removal is the only known cultural
control practice

For additional information on any of these
diseases, please refer to references listed in
"Peach Pests III."

%% ^% %% %% %%

rj% •^ rj% rj* rj%

Apple Maggot Fly Behavior:
Probability of Fly Capture on
Red Sticky Spheres in Relation to
Fly Age and Fruit Maturity

Max P. Prokopy, Jian Jun Duan, Gabriela G. Galarza, and Ronald J.

Prokopy

Department of Entomology^ University of Massachusetts

To augment our current program of second-
level apple IPM involving the use of baited
sticky red spheres to intercept and capture apple
maggot flies (AMF), we have been tracking
foraging behavior patterns of female AMF. We
want to know if the probability of a fly being
captured on a sphere or of laying eggs in apples
changes as flies age or apples mature.

Methods Used

In 1991, two potted apple trees were placed
in screen cages on the campus of the University
of Massachusetts. Each tree had approximately
the same canopy size as a normal four-year-old
dwarf (M.9) fruit-bearing tree. We placed either

50 green or 50 red evenly-spaced Gravenstein
apples on a tree. The leaf-to-fruit ratio was
about 20: 1 . The green fruit were picked on June
19 and had a diameter of about 3 cm. The red
fruit were picked on August 1 and had a diam-
eterofabout4.5cm. In all, 36 AMF of each of five
ages were tested in the presence of only green
finiit, and 30 of each of five ages in the presence
of only red fruit. The flies were collected fix)m
naturally infested fruit and were 3, 7, 11, 15, or
19 days old when tested. FUes seven days old or
younger usually are not capable of lajdng eggs in
fruit.

A single fly was released onto a leaf at the
lower center of the tree. A sticky red sphere,
baited with one vial of the synthetic apple odor

Fruit Notes, Winter, 1993

Table 1. Behavior of apple maggot females of different ages when
released individually on a caged apple tree containing a sticky red
sphere baited with butyl hexanoate and 50 green or 50 red
Gravenstein apples.*

Flies that

Flies

Number of

laid one

Fruit that

captured

fVuit visited

or more

eggs

received an

(%)

¥*

per fly***

(%)***

egg(%)

Fly

age

(days) Green

Red

Green Red

Green

Red

Green Red

3 25 b

27 b

1.9 a 2.8 b

Ob Ob

7 68 a

47 a

2.7 a 3.9 a

6 b

2 b lb

11 61 a

57 a

1.8 a 3.8 a

22 a

10 a

12 a 6 b

15 71 a

57 a

1.7 a 4.3 a

26 a

13 a

10 a 5 b

19 64 a

57 a

1.6 a 2.7 b

19 a

30 a

8 a 19 a

Values in each column not followed by the same letter are
significantly different at an odds ratio of 19:1.
Represents flies captured on a sphere before leaving tree or
before one hour had elapsed.
*** Visits and egg laying before being captured on a sphere, before
leaving the tree, or before one hour had elapsed.

butyl hexanoate, was placed in the upper part of
the tree canopy. After the fly was released, its
movement was tracked during one hour of forag-
ing within the tree. Tracking involved recording
all leaves and fruit visited, all oviposition at-
tempts and ovi}X)sitions, and whether or not the
fly was captured on the sticky sphere. Any finiit
iQ which the fly made an oviposition, or an
attempt at it, was removed from the tree and
dissected to see if eggs had been laid.

Results

Fly captures when either green or red fruit
were on the tree increased significantly when
the flies were more than three days old (Table 1 ).
For flies seven or more days old, consistently
more were captured when fruit were green than
when they were red. Sixty-six percent of flies
seven or more days old were captured when fruit
were green; whereas, 55 percent were captured

when finiit were red.

Regardless of fly age, red fruit received more
visits than green fruit (Table 1). Flies 1 1 or more
days old were more hkely to oviposit in a frtiit
than were younger ones. Interestingly, except
for the oldest flies tested, a greater percentage of
green fruit than red fruit received eggs.

Conclusions

Our results demonstrate that the age or
maturity of a female AMF can strongly affect its
fruit foraging and egg laying behavior and the
probabihty of capture on a baited sticky red
sphere. Once a female reached seven days of
age, the chance that it would be captured on a
sticky red sphere baited with butyl hexanoate
hung in our test trees was 50% or better. As fly
age increased above seven days, the probability
of capture on a sphere did not increase, but the
probabihty that it would lay eggs before being

Fruit Notes, Winter, 1993

captured on a sphere did increase. This result
indicates that for greatest effectiveness in con-
troUing AMF, baited sticky red spheres should
be hung very early in the fly season, before
immigrating AMF have reached maturity. In
addition, our findings suggest that while green
apples may receive fewer visits by AMF than red
apples, green apples may be more susceptible to
oviposition by arriving AMF. This result again
affirms the need to hang baited sticky red

spheres early in the fly season for greatest
effectiveness in avoiding finiit injury by immi-
grating AMF.

Acknowledgements

This work was supported by the Science and
Education Administration of the U.S.D.A, im-
der grant 8900901 from the Cooperative Re-
search Grants OfBce and by a USDA grant
under the NE-156 Apple IPM project.

^% %% %% ^10 «^

rf* •^ rf% #J% rj%

Evaluation of Four Rootstocks and
Two Mcintosh Strains

Wesley R. Autio and Franklin W. Southwick

Department of Plant & Soil Sciences, University of Massachusetts

Through the 1960's and 1970's, the trend
in the New England apple industry was from
seedling-rooted trees to trees on M.7 or similar
sized rootstocks. In the latter part of the 1980's,
the trend shifted toward smaller trees. In the
1990's, growers are planting significant num-
bers of dwarf trees, mostly on M.9 and Mark
rootstocks. In 1979, a planting was established
at the University of Massachusetts Horticul-
tural Research Center to assess rootstocks in
the size range from M.7 to M.9.

The planting included Rogers Red Mcin-
tosh and Macspur Mcintosh on M.7A, M.26, M.9
(trained either to a post or on a 4- wire vertical
trelhs, seven-feet tall), andM.9/MM. 111. Seven
replications were planted, and each replication
had four trees of each cultivar/rootstock combi-
nation. Two trees of each group were used for
data collection, and any Macspur that reverted
to a nonspur habit was eliminated from the
experiment. Normal fertilization and pest man-

agement practices were used. All trees were
maintained as central leaders. With the excep-
tion of tjdng branches to the wires in the trellis
treatment, very Uttle limb positioning was per-
formed in the planting.

After 10 growing seasons, trees on M.7A
were the tallest, regardless of Mcintosh strain
(Table 1). Trees on M.26 and M.9/MM.1 1 1 were
similar in size and intermediate. Trees on M.9
were the shortest. Rogers trees were signifi-
cantly taUer than Macspur trees. Tree spread
followed a similar trend (Table 1); however,
trees on M.9 trained to a trellis had a greater
tree spread after 10 seasons than those trained
to a post. Clearly, this difference related to the
support provided to lateral branches by the
trelhs wires.

Tree spread was used to calculate poten-
tial tree density (Table 1). It was assumed that
trees could be planted 1 percent closer than the
spread measured after 10 seasons. Seven feet

Fruit Notes, Winter, 1993

Table 1. Tree size after 10 growing seasons and projected tree densities of Rogers Red
Mcintosh and Macspur Mcintosh on different rootstocks.

Tree height

Tree spread

Tree density

(fl)

(ft)

(trees/acre)*

Treatment

Rogers

Macspur

Rogers

Macspur

Rogers

Macspur

M.7A

14.8

a* 14.9

15.8

a 14.5

145

c 172

M.26

12.0

b 9.9

13.2

be 11.5

202

b 254

M.9 (post)

8.8

c 8.4

10.2

d 9.3

297

a 363

M.9 (trellis)

9.3

c 9.0

12.9

c 10.6

295

a 363

M.9/MM.111

11.5

b 10.0

14.3

b 12.0

172

b 239

Average

11.3

••• 10.4

13.3

- 11.5

222

- 278

Distance between trees within rows was projected to be 10% less than the natural tree

spread, allowing for overlap of trees. The distance between rows was the distance

between trees plus seven feet, with the exception of the trelhs, which was assumed to be

spaced 13 feet between rows.

For the three characteristics in this table, the relative differences between rootstock

treatments were statistically similar for each strain. The letter presented between the

Rogers and Macspur columns represents the differences among rootstock treatments only.

For a particular characteristic, if not represented by the same letter, rootstock treatments

are significantly different at odds of 19:1.

Rogers and Macspur averages are different at odds of 999:1.

were added to the distance between trees in a
row to determine between-row spacing, with the
exception of the trellis. Because of the shape of
the trelUs, it was assixmed that all trellis combi-
nations could be maintained at 13 feet. (This
assumption is conservative, and it depends on
the final width of the trellis rows.) Potential tree
density ranged from over 360 trees per acre of
Macspur/M.9 to 145 trees per acre for Rogers/
M.7A, Because of the difference in spread,
Macspur could be planted at approximately a 20
percent higher density than Rogers, assuming
no reversion.

Figures 1 and 2 show the cumulative
yield per tree for the rootstock treatments and

the Mcintosh strains, respectively. (jeneraUy,
larger trees )delded more per tree than smaller
trees, that is, trees on M.7A yielded more than
those on M.26, which yielded more than those on
M.9. The exception is M.9/MM. 111. Trees on
M.9/MM.111 yielded significantly less than the
trees on M.26, which were of similar size. Trees
on M.9 trained to a treUis yielded more than
those trained to a post. This result may have
occurred because the trellis maintains wood at
a more desirable angle for continued Smiting
and allows for upper branches to fill a larger
portion of the canopy than when no additional
support is provided. Additionally, the larger
Rogers trees yielded more than the Macspur

Fruit Notes, Winter, 1993

Rootstocks:

-»-M.7A

^15

-°-M.26

-^ M.9 (post)

/ b

i»

^ M.9 (trellis)

|io

-•-M.9/MM.111

y Ztf:=C^

Cumulative

...>^^'

1982 1983 1984 1985 1986 1987 1988

Figiire 1. Cumulative yield per tree through the tenth

growing season for each rootstock treatment (average of the

two Mcintosh strains).

— 15

•55 10

>
E

Strains:
^*" Rogers
^ Macspur

/L^^^^'o

1982 1983

1984 1985

1986

1987

1988

Figure 2. Cumulative jdeld per tree through the tenth
growing season for each Mcintosh strain (average of the five
rootstock treatments).

Truit Notes, Winter, 1993

o
o

Rootstocks:
-•-M.7A

-^M.26

-^ M.9 (post)

0C ^

•

^M.9 (trellis)

/ X^y^°

1.2

♦M.9/MM.111

y ///^ ^

y1^^^^:^y^

.^^'^

1982 1983 1984 1985 1986 1987 1988

Figure 3. Cumulative yield per acre through the tenth

growing season for each roots tock treatment (average of the

two Mcintosh strains).

Strains:

^ Rogers

"H- Macspur

y^ ^

y^^^b

•0
»

^^^:^

3
E
3

^^---^

1982 1983 1984 1985 1986 1987 1988

Figure 4. Cumulative yield per acre through the tenth

growing season for each Mcintosh strain (average of the five

rootstock treatments).

Fruit Notes, Winter, 1993

Table 2. Economic comparison of the five rootstock treatments (average of both strains of
Mcintosh). Establishment costs were modified fi-om those presented in Fruit Notes 55(4): 1-5.
Growing and harvesting costs were modified from those presented in Fruit Notes 53(l):4-7.

Item

M.7A

M.26

M.9
(post)

M.9
(treUis)

M.9/
MM.lll

Costs:

Establishment

Growing

Harvesting

$920
$6,660
$4,780

$2,030
$6,540
$5,040

$2,980
$7,010
$5,170

$3,900
$7,190
$6,170

$1,730
$6,540
$3,730

Total yield (bu)*

2780 b

2930 b

3010 b

3590 a

2170 c

U.S. Extra Fancy,
1987 + 1988 (%)•

37 d

62 be

64 b

51 c

80 a

Fruit count per
42 lbs, 1988*

140 a

125 b

120 c

119 c

144 a

Estimated crop
value

$25,890

$36,210

$39,310

$42,650

$25,370

Net returns

$13,530

$22,610

$24,150

$25,390

$13,370

Within a row, means
19:1.

not followed by the same

letter are significantly different at odds of

trees.

Obviously, the amount of fi*\iit obtained
fix)m individual trees is of little importance
when the trees are at different densities. Fig-
ures 3 and 4 show the cumulative yield per acre
for the rootstock treatments and the Mcintosh
strains, respectively. M.9 trained to a trelHs
resulted in the highest jdelds per acre. M.9
trained to a post, M.26, and M.7 were statisti-
cally similar in cumulative yield, and M.9/
MM.lll resulted in the poorest yield per acre,
yielding only 60 percent of trees on M.9 trained
to a trelUs. Macspur trees outyielded Rogers
trees on a per-acre basis.

Factors other than yield must be consid-
ered before selecting the most desirable root-

stock or training system. Establishment, grow-
ing, and harvesting costs vary fi-om treatment to
treatment. Estimates of these differences are
presented in Table 2. Also, packout is an impor-
tant consideration. Table 2 presents the percent
of a whole-canopy random sample which made
the U.S. Extra Fancy grade in 1987 and 1988.
Trees on M.9/MM.111 produced the most high
grade fruit; whereas, trees on M.7A produced
the least. Of the M.9-rooted trees, those on posts
produced more U.S. Extra Fancy finiit than
those on trellises. These numbers were used to
approximate the grade distribution of fi-uit. It
was assimaed that one half of the fi-uit not
making U.S. Extra Fancy were Number 1 and
the other half were used for cider. These esti-

Fruit Notes, Winter, 1993

$30

Rootstocks:

1 $25

-fr^M.TA

2^ $20
u

-0-M.26

-^ M.9 (post)

]

|$15

-A-M.9 (trellis)
♦ M.9/MM.111

1/ y

1 $10

yi'/ -^

ji^

Cumulative

U1 o

y^^^6^

-$10
19

79 1980 1982 1982 1983 1984 1985 1986 1987 1988

Figure 5. Cumulative net returns per acre for the ten years

1979 through 1988.

mates are conservative, since the sample for
grading was random. Multiple pickings would
have resulted in greater percents in the highest
grade. Additionally, no summer pruning was
performed in our trellis treatment, and fruit
quahty clearly would have benefitted greatly
fi*om summer pruning.

Fruit size also varied significantly
among the treatments (Table 2). The average
fruit from trees on M.7 or M.9/MM.111 were
140-count or smaller. Fruit from trees on M.9
averaged nearly 120-count in size, and those
from trees on M.26 were somewhat smaller than
120-count.

When size and grade are considered,
along with yield, crop value can be estimated
(Table 2). Accomiting for crop value and costs,
Table 2 presents the net returns possible from
these treatments. The two M.9 and the M.26
treatments produced similar returns, with the

M.9 trellis treatment giving approximately five
percent more, and the M.26 treatment giving
approximately six percent less than the M.9
post. The M.7A treatment netted only 53 per-
cent of what the M. 9 trellis netted. M. 9/MM. Ill
was slightly less profitable than M.7A.

When evaluating different rootstocks
and training systems, it is necessary to assess
many different characteristics. Costs of estab-
hshment, training characteristics, jrield poten-
tial, fruit grade, fruit size, and costs of manage-
ment must all be considered before selecting an
appropriate combination. The best system is
the one that can be managed within the con-
straints of a particular grower and that provides
the best net returns to the orchard. In this
study, trees on M.9 and on M.26 were the most
profitable over the first ten years, and clearly
would be better choices than trees on either
M.7AorM.9/MM.lll.

^f^ %f^ %{« «£# %t«
0^ rj% rj% •Y* •Y*

Fruit Notes, Winter, 1993

Do Overwintering Red Mite Eggs
Portend Summer Mite Troubles?

Jennifer Mason, Margaret Christie, and Ronald Prokopy
Department of Entomology^ University of Massachusetts

Among foliar pests, European red mites
(ERM) remain a major problem for apple trees.
They can be particvdarly difGcvdt in second- level
IPM blocks, where growers are dependent on
predator mites to control summer ERM popula-
tions. In these blocks, current non-biological
control measures consist of one or two dormant
oil sprays in the spring prior to egg hatch. To
maintain control of ERM, predators build up to
levels capable of controlling the mites that
hatch. Unfortunately, it is difiicult to balance
spring oil control of ERM and encouragement of
a healthy population of predator mites. This
leads to the question: Can prebloom oil alone
effectively control summer ERM populations?

During January of 1992, we collected 200
buds per orchard from 11 orchards that partici-
pate in the second-level IPM project. Six of these
were full second-level IPM blocks, and five were
transitional second-level blocks. The percentage
of buds with ERM eggs present was recorded for
each block, and orchards were placed into three
categories: low (0-33%), medium (34-66%), and
high (67-100% of buds with mite eggs).

During late spring and summer months,
mite populations in each block were recorded as
part of normal IPM scouting procedures. ERM
presence or absence was counted on 200 fruit
cluster leaves beginning in May and continuing
through September. Examination of peak ERM
populations in the second-level IPM blocks in
May showed little or no apparent relationship
between winter ERM egg percentages and
spring mite numbers. Peak ERM populations in
June, however, were related to winter egg per-
centages (Table 1). The low and medium ERM
egg groups both had very low June ERM popula-

tions, but all orchards in the high ERM egg
group had substantial numbers of Jxine mites.
In first-level blocks there appeared to be no
consistent relationship between overwintering
egg numbers and June mites, which were low in
all of these orchard blocks (Table 1).

Of the second-level blocks, all received at
least one dormant oil spray prior to egg hatch in
the spring (Table 1). In the high group, two
blocks had received two sprays. In the low and
medium orchards, it appears that dormant oil
sprays were sufficient to control mite popula-
tions through June. In the orchards in the high
group, however, even those receiving two appli-
cations had thriving ERM populations by the
endof Jvme.

Further work needs to be done on the rela-
tionship between dormant oil sprays, overwin-
tering ERM eggs and resulting early summer
ERM populations before any firm conclusions
can be drawn. If these results are estabhshed as
fact, then oil spray recommendations may need
to be revised for blocks where high numbers of
overwintering ERM eggs are foxuid in winter
coimts. Without a strong predator population,
these orchards may be subjected to large sum-
mer ERM populations if they depend on normal
amoimts of prebloom oil to be effective. Higher
rates of oil (e.g., three gallons of oil per 100
gallons of water) at green tip or half -inch green
may be necessary, with a second oil treatment at
a lower rate at tight cluster. It is p>ossible,
however, that the higher mite numbers in the
high blocks may be "attractive" to predator
populations, and that these orchards may even-
tually become areas of good biological control.

Fruit Notes, Winter, 1993

Table 1.

Overwintering egg

and peak mite levels in eleven second-level and

eleven first-level IPM blocks.

Number of

dosage

Twigs with

Leaves with

prebloom oil

equivalents

overwintering

ERMin

Orchard

sprays

of oil

eggs (%)

June (peak %)

Second-level IPM blocks

1.8

4.5

2.5

0.9

8.5

0.0

1.0

16.0

0.5

1.5

35.0

0.0

44.5

0.0

1.3

56.0

0.5

1.5

58.0

1.5

0.8

81.0

13.0

0.3

90.0

19.5

1.0

90.0

13.0

1.5

92.0

19.5

First-level IPM blocks

1.8

4.5

2.5

1.3

31.0

1.5

37.5

2.0

1.3

40.0

2.5

1.5

44.0

0.5

1.0

63.0

0.5

0.8

75.5

6.5

0.8

78.5

0.0

1.5

81.0

0.0

1.5

81.5

0.0

1.0

87.0

4.0

Acknowledgements

We are grateful to the Massachusetts Soci-
ety for Promoting Agriculture, the USDA North-

east Regional IPM Competitive Grant Program,
and State/Federal IPM fimds for funding this
project.

%% %% ^t^ %% %f^

ry% •^ ry% ry% rj%

Fruit Notes, Winter, 1993

Evaluation of Red Coloring Strains of
Gala Apple

Duane W. Greene And Wesley R. Autio

Department of Plant & Soil Sciences, University of Massachusetts

Gala is an apple that has experienced a
recent and rapid rise in popularity throughout
the world. It is being planted heavily in Europe,
South America, New Zealand, and the United
States. Gala represented 25% of all apple trees
sold by Washington State nurseries in 1990.

Gala has many desirable characteristics,
including very high flesh quahty, attractive
appearance, precocity, and high productivity.
The original strain of Gala is not a red apple, but
rather, a cream-yellow one with an orange-red
cheek. Mutations in fruit skin coloring occur
readily. There is a general preference among
nurserymen and growers for red coloring strains
of a cultivar because there is the perception that
these strEuns are preferred by the consumer. It
is commonly accepted that the red coloring
strains of Delicious that are being sold today,
although very attractive, have decidedly infe-
rior quality compared
with the original Deli-
cious strain. Further,
production from some
strains of Delicious may
be only one third of more
productive strains.

There has been no
comprehensive evalua-
tion of the commonly-
available strains of Gala.
A Gala strain trial con-
taining Kidd's D-8 (stan-
dard). Royal, Regal
(Fulford), Imperial, and
Scarlet Gala was planted
at the University of Mas-
sachusetts Horticultural
Research Center in
Belchertown in 1988.
This report summarizes

growth, flowering, fruit characteristics, and
fi*uit quahty of these five strains of Gala.

lyees

Kidd's D-8 and Royal Gala were obtained
fi-om Stark Bros. Nursery, Louisiana, Missouri,
and Imperial and Regal Gala were obtained
fi-om Newark Nursery, Hartford, Michigan. All
trees were on M.26 roots tock and were similar in
caHper at planting. Propagating wood of Scarlet
Gala was obtained fix)m Txu-key Hollow Nursery
(Cumberland, Kentucky) in the spring of 1987,
bench grafted on M.26 rootstock and then lined
out in the nxirsery. In the spring of 1988, trees
were planted in a randomized complete block
design with eight rephcations. Each tree was
supported by a one-inch x 10-foot metal conduit
post set three feet in the ground. The first data
on these trees were collected in 1990.

Table 1. Growth in 1990 of five strains of Gala planted in 1988.

Strain

Kidd's

Royal

Scarlet

Imperial

Regal

Trunk cross-

Final

sectional

trunk

area

cross-

Tree

increase in

sectional

height (ft)

spread (ft)

1990 (in=^

area (in^)

9.6 a

7.9 a

1.4 a

5.3 a

9.9 a

7.6 a

1.5 a

5.6 a

8.9 a

5.0 b

1.4 a

4.0 b

10.2 a

7.6 a

1.7 a

5.2 a

9.2 a

6.9 a

1.6 a

4.9 a

Means within columns not followed by the same letter are
significantly diff'erent at odds of 19:1.

Fruit Notes, Winter, 1993

Growth

Prior to bud break in 1990, a line was
painted 20 inches above the soil surface and the
trunk circumference was measured. After leaf
fall, height, spread, and trunk circumference
were measured.

At the end of the third leaf. Gala strains
differed little in vegetative growth. The height
of all Gala strains was comparable, while the
spread of Scarlet was smaller than that of the
others (Table 1). The trunk circumference in-
crease of all Gala strains in 1990 was similar,
but the total cross-sectional area of Scarlet was
less. Scarlet Gala trees were smaller at planting
because they were bench grailed and grown for
only one year; the other strains were budded on
roots that were in the ground for one growing
season and grew an additional year after bud-

ding. Therefore, the small spread and trunk
cross-sectional area of Scarlet Gala trees is
probably a reflection of the tree size at planting
rather than inherent vigor of the strain.

Bloom, and Fruit Set

Two limbs per tree were selected at the pink
stage of flower development and the circumfer-
ences were measured. The numbers of blossom
clusters on one-year-old and two-year-old wood
were counted. In 1991, fi-uit set also was as-
sessed on these two hmbs in July by determining
separately the fruit persisting on one-year-old
and on older wood.

Spur bloom density was lowest on Scarlet
Gala and highest on Royal Gala in 1990, but
there were no differences in 1991 (Table 2).
Fruit set on all strains of Gala was comparable

Table 2.

Flower bud formation and fruit set of five strains of (Jala.*

Bloom density

Fruit set

(blossom clusters/in

Mimb

(firuit/in" limb

Strain

cross

.-sectional ar

ea)

cross-sectional area)

Spur

One-yr-old

Total

Spur

One-yr-old

Total

1990

Kidd's

52 ab

124 a

176 ab

Royal

63 a

123 a

186 a

Scarlet

16 c

128 a

144 be

—

Imperial

34 be

103 a

137 c

Regal

46 ab

102 a

148 be
1991

Kidd's

67 a

147 a

214 a

35 a

85 a

121 a

Royal

66 a

127 a

193 ab

44 a

77 a

121 a

Scarlet

61 a

132 a

192 ab

30 a

77 a

108 a

Imperial

48 a

117 a

164 b

25 a

67 a

92 a

Regal

52 a

134 a

185 ab

23 a

68 a

92 a

* Means

within columns and years not followed by

the same letter are

significantly different at odds of 19:1.

Fruit Notes, Winter, 1993

and very heavy. In general, the bloom density of
Imperial Gala was lower than that of the other
strains. Bloom on all trees was considered
'snowball* and excessive when compared to most
other cultivars. Although the lower bloom den-
sity of Imperial may have been real, it is of Uttle
practical significance because of the excessive
bloom that occurred on all strains in this trial.
All strains of Gala bloomed extensively and
comparably on one-year-old wood, accounting
for over two-thirds of the bloom. Following
June-drop, over two- thirds of the fruit that per-
sisted originated from one-year-old wood. Fruit
produced from bloom on one-year-old wood gen-
erally was small and the quality was inferior.
Since fruit size of Gala is normally small, and

lateral fi^dt are even smaller, it is important to
develop a thinning strategy for all strains of
Gala to remove fiiiit developing from lateral
bloom selectively.

Fruit Characteristics and Quality

At normal harvest, 15 fruit per tree were
sampled. Fruit were weighed, flesh firmness
and soluble soUds measured, ground color and
starch pattern were rated, and p>ercent red color
on each fi-uit was estimated to the nearest 10%.
In 1991, finit were harvested September 3, 12,
and 19. Additionally, stem-end cracking was
evaluated and the length-to-diameter ratio was
determined.

Table 3.

Fruit characteristics of five strains of Gala at harvest.*

Fruit

size

Flesh Soluble Red

Ground

i'edicel-end

(count/ firiimess

solids color

color

Starch

L/D

cracking

Strain

42-lb box)

(lbs)

(%) (%)

index**

index***

ratio

(%)****

1990

Kidd's

111 a

19.2 ab

14.2 b 74 b

7.1 b

5.6 a

Royal

114 a

19.9 a

14.6 b 88 a

7.1 b

5.0 a

Scarlet

119 a

19.7 a

15.0 ab 80 ab

7.2 b

5.4 a

—

Imperial

110 a

20.0 a

14.5 b 86 a

7.2 b

4.7 a

—

Regal

107 a

18.3 b

15.7 a 84 ab
1991

8.1 a

6.8 a

Kidd's

135 b

18.3 b

13.0 c 70 c

6.7 b

5.4 a

0.86

a 2.2 b

Royal

131 b

18.0 ab

13.2 b 77 b

6.8 b

5.2 a

0.87

a 1.1 b

Scarlet

126 b

19.6 a

14.2 a 78 b

6.9 b

5.1 a

0.86

a 4.6 b

Imperial

126 b

18.6 b

13.3 b 87 a

6.9 b

5.3 a

0.87

a 6.7 b

Regal

112 a

18.7 ab

14.4 a 89 a

7.5 a

5.9 a

0.86

a 21.1 a

* Means within col

umns and

years not followed by the same letter are significantly

different at odds of 19:1.

** Adapted from a

New Zealand Gala ground color

chart provided

by Dr. Ian

Warrington, 1 =

green; 10

= orange.

*** Starch chart developed by W. R. Autio, 1 =

immature; 9 = oveiinature. 1

*♦** Cracking on the third harvest, September 19, 1991.

Fruit Notes, Winter, 1993

There were no differences in fi-uit weight
among strains in 1990, but in 1991, Regal Gala
stood alone as the strain with the largest finiit
(Table 3). Strains differed in flesh firmness and
soluble solids but the differences were not con-
sistent in the two years evaluated. All strains of
Gala colored well, although red coloring selec-
tions generally had more red color. Quantitative
differences in red color among red coloring
sports were not consistent. Regal had the high-
est ground color rating, indicating a greater loss
of chlorophyll. Strains did not differ in either
starch index or length-to-diameter ratio. Sig-
nificant stem-end cracking did not occur vmtil
the last harvest in 1991 and then it occurred
only on Regal Gala.

There were clear indications that Regal Gala
was an early maturing strain. As Gala ripen,
ground color index, starch index, red color,
soluble sohds and finiit cracking increase. Regal
Gala differed consistently from the other strains
in each of these characteristics in a way that
indicated advanced ripening.

Cracking at harvest has been cited as a
problem with Gala in some areas, and that

problem may be associated with uneven ripen-
ing. If trees are thinned properly and pruned to
allow good light penetration, we have observed
that Gala can be picked injust two harvests. No
significant cracking occurred until the last har-
vest, and even then, it was restricted to Regal
Gala. All strains could have been harvested
before September 19, 1991, and Regal Gala a
week earlier, when cracking was minimal.
Therefore, we feel that cracking is not a problem
with Gala if finiit are harvested at the proper
time. When cracking does become a problem,
fi-uit maturity has advanced to a point where
fi-uit feel 'greasy*, and the postharvest life has
been diminished significantly.

Sensory and Visual Evaluation

In 1991, sensory and visued evaluation of
strains (Table 4) was done by 17 judges includ-
ing pomology faculty, pomology graduate stu-
dents, technical assistants, and students in an
orchard management class. Each panelist
evaluated three repUcations. A replication in-
cluded one fi-uit of each of the five strains and one

Table 4.

Visual and sensory evaluation of five strains of Gala at harvest*

Skin Flesh

Strain

Aroma

toughness crispness

Juiciness !

Sweetness

Acidity

Starchiness Flavor

Kidd'8

-0.1 a

0.2 a 0.1

0.2 a

-0.3

0.0 a 0.1c

Royal

-0.3 a

0.5 a 0.8

0.4 a

0.5 a

0.6

-0.2 a 0.9 a

Scarlet

0.0 a

0.5 a 0.8

0.3 a

0.4 a

0.8

-0.1 a 0.7 ab

Imperial

-0.6 a

0.5 a 0.2

0.3 a

0.1 a

0.3

-0.2 a 0.4 be

Regal

-0.1 a
Color

0.6 a 0.4
Color

0.4 a

0.7 a
Overall

0.5

0.0 a 1.1 a

Kidd'8

brightness

uniformity

Attractiveness

desirability

0.1c

-0.1 c

0.1 b

0.2 b

Royal

0.8 b

0.9 b

0.7 b

0.8 a

Scarlet

0.7 b

0.6 be

0.5 b

0.7 a

Imperial

0.7 b

0.8 b

0.5 ab

Regal

1.7 a

1.6 a

1.0 a

•Means within columns not followed by the

same letter

are significantly different at odds of 19:1.

Fruit Notes, Winter, 1993

reference fruit to which all of the strains were
compared. The reference fruit was Kidd's D-8,
and this fact was not divulged to the panehsts.
Judges scored each fi*uit on a horizontal scale
with opposite descriptive terms at each end of
the line and the center represented by the refer-
ence fruit. The intensity of the deviation of each
fi-uit from the reference fruit was recorded by a
pencil mark either to the right or left of the
reference fruit.

Taste pgmeUsts were able to distinguish dif-
ferences in quality and appearance among the
Gala strains. Royal, Scarlet, and Regal Gala all
were judged to have better flavor than Kidd's D-
8. Royal and Scarlet had the crispiest flesh. The
flesh of £dl red-coloring strains was more acid
than Kidd's D-8. There were no differences
eunong strains in aroma, skin toughness, juici-
ness, sweetness, or starchiness. Regal Gala was
judged to be the most attractive Gala strain. It
also had the brightest red color and the most
uniform color.

There are legitimate concerns that the Gala
strains selected solely on the basis of red skin
color may not have the same high quality char-
acteristics of the original Kidd's D-8 strain. Not
only were all strains judged to be equal to Kidd's
D-8, but when panelists considered all factors
and rated overall desirability, Royal, Scarlet,
and Regal Gala were selected as being better
than Kidd's D-8.

Conclusions

Growth Emd bloom characteristics of Gala
strains appeared to be similar; however, all
strains bloomed heavily on one-year-old wood.
Because of the lower value of fruit borne on this
wood, thinning strategies should target these
fruit.

Regal is an early maturing strain of Gala,
and was selected by paneUsts as the most attrac-
tive strain. Royal, Scarlet, and Regal were
judged to have better flavor and to be, overall,
more desirable than Kidd's D-8 Gala.

%|# %% %% ^f^ ^%

rj* #1% rj% #1% •Y*

Fruit Notes, Winter, 1993

Spiders in Second-level and First-level
Apple IPM Blocks

Joanna Wlsniewska, Yanghe Yang, and Ronald Prokopy
Department of Entomology^ University of Massachusetts

One of the principal practices of full second-
level IPM is to control key summer fruit pests by
a combination of behavioral and ecological tech-
niques, thus allowing beneficial predators and
parasitoids to increase enough to control sum-
mer foUar pests. Spiders may be an important
group of such predators. Insecticides can reduce
numbers and diversity of spiders in apple or-
chards. Therefore, full second-level IPM, which
eliminates insecticide use Eifter early June, may
allow spiders to prohferate in apple orchards.

In 1992, we assessed spider populations in
blocks of apple trees under full second- level IPM
compared with first-level IPM practices. Addi-
tionally, we conducted a laboratory test of the
effects of Guthion™, Thiodan™, and Omite™ on
the most common spider species found in second-
level IPM blocks.

Besides these evaluations, we also were in-
terested in the effects of herbicides on spider
populations in these orchards. Frequently, veg-
etation growing under apple trees is controlled
in commercial orchards with herbicides applied
early in the growing season, v/hile vegetation
between the tree rows is mowed throughout the
season. These practices reduce competition for
nutrients, lower humidity (which may contrib-
ute to higher disease pressure), and eliminate
alternative sources of food and shelter for many
orchard pests. Herbicides can decrease spider
numbers in vegetable production systems
(Riechert and Bishop, 1990), but their effects
have not been examined in an orchard system.
Hence, in 1992, we examined the effects of
herbicide treatments on the number of spiders
on apple trees in second-level IPM blocks.

Spider Numbers in Full Second-level
and First-level IPM Blocks

Spiders were sampled in six apple orchards.

Each orchard contained a six- to nine-acre block
imder full second-level IPM and a nearby six- to
nine-acre block under grower-supervised first-
level IPM. Guthion and Thiodan were used in
both types of blocks through early or mid-June
to control early-season insect pests. After mid-
June, second-level blocks received no insecti-
cides while first-level blocks received an average
of 2 sprays of Guthion or Imidan (once in July
and once in August). All blocks were sprayed
with carbaryl in early June to thin finiit.

Beginning in early July, spiders were
sampled on twenty randomly chosen trees every
two to three weeks in both tjT)es of blocks in each
orchard by tapping tree branches with a rubber
mallet over a two-by-two-foot tray. Spiders were
preserved in 70% alcohol and returned to the
laboratory for identification, a process not yet
complete.

Figure 1 summarizes the results obtained
over the entire season. The mean number of
spiders collected per tree at the beginning of the
sampUng period (July 2) was very low and W£is
the same in both second-level and first-level
IPM blocks. As the season progressed, however,
these numbers increased to 1.5 spiders per tree
by late September in the second-level blocks
compared with 1.0 spiders per tree in the first-
level blocks. Data trends were similar for each
orchard considered, except for one orchard
where there seemed to be no difference between
the two types of blocks.

The low numbers of spiders per tree in early
July in all blocks may have been due to spraying
for plum curculio, which extended through early
to mid-June in all blocks. Beyond mid-June,
growers continued to use insecticides in the first-
level blocks but not in the second-level blocks.
This difference probably accounted for the
greater abundance of spiders in the second-level

Fruit Notes, Winter, 1993

1.8

1.6

O 2nd level IPM
• 1st level IPM

a
P

1)
t)

1.4
1.2

/ -

•g
'q.
in

1.0
0.8

/ /

/•:

c
o
l>

0.6
0.4

/ /

V / b

0.2

-4==^::^

»
b

0.0

7/2 7/17 7/30 B/23 9/10

Collection period

9/24

Figure 1. Numbers of spiders collected per tree ia full second-
level and first-level IPM blocks during 1992. Means within
each date accompanied by a different letter are significantly
different at odds of 19:1.

blocks during August and September, a conclu-
sion reinforced by laboratory findings (next sec-
tion).

Insecticide and Miticide Effects
on Spiders

To test the effects of insecticides and miti-
cides on spiders directly, a laboratory test was
conducted on the most common spider species
found in all six orchards: Araniella displicatta
(Araneidae). All individuals tested were imma-
ture, averaging 2 mm in size (the size found in
early September in the field). All were collected
at the same time in the same orchard. Spiders

ity to pesticides.

cation). Ten additional
jars were coated with
water as controls.

After 9 hours all 10
spiders in the Thiodan
jars were dead, as were 9
of the 10 in Guthion jars.
None died in the Omite or
control jars, although one
spider died in the Omite
jar after 45 hours.

These results indi-
cate that these insecti-
cides were highly toxic to
spiders, or at least to this
particular found species.
Omite, on the other hand,
was not very toxic to this
species of spider. It would
be inappropriate, how-
ever, to apply these find-
ings to all orchard pesti-
cide-use situations, in
that pesticide effects may
not be confined to pure
contact toxicity. Also,
many different spider
species exist and some
may differ from A.
displicatta in susceptibil-

Effects of Herbicides on Spiders
on Apple Trees

To determine if herbicide treatment of
ground cover affects the number of spiders on
trees, some trees in five second-level IPM blocks
were not treated with herbicide while a herbi-
cide treatment was apphed in May beneath
other trees. Two additional blocks (likewise
under full second-level IPM) at the University of
Massachusetts Horticultural Research Center
(HRC) in Belchertown also were employed in
this experiment. Herbicides vised included para-

were placed individually in glass jars coated quat and simizine in the HRC blocks, and these

with the substance to be tested. Ten jars were herbicides as well as Post™, amate, and

coated with Guthion, 10 with Thiodan, and 10 Fusilade™ in the five second-level IPM blocks,

with Omite (each at standard field rate of appli- The two HRC blocks consisted of dwarf trees

Fruit Notes, Winter, 1993

3.5

3.0

" 2.5

«
a

\-
«)
■o
■q.

2.0

-s 1-5

u
2

1.0

0.5 -

0.0

O herbicides
• no herbicides

7/16 8/19

Collection period

8/31 9/15

Figure 2. Effects of herbicide treatment of ground cover on the
mean number of spiders per tree at different times of the
season. This portion of the study was conducted in two blocks
at the University of Massachusetts Horticultural Research
Center which were under second-level IPM. Means within
each date accompanied by a different letter are significantly
different at odds of 19:1.

(seven feet tall). On each sampling occasion (five
in all, starting Jvdy 1), spiders were collected
from 40 trees of each treatment. The five sec-
ond-level IPM blocks contained larger trees (10
to 13 feet tall). Forty to 65 of these in each
treatment were sampled on four different occa-
sions from each orchard. Sampling was carried
out by tapping the branches as described above.
In the five full second- level IPM blocks, her-
bicide treatments did not have any effect on the
number of spiders on trees. Mean numbers of
spiders per tree show the same seasonal trend
for herbicide as well as non-herbicide treat-
ments. In the two HRC blocks (Figure 2),
herbicide-treated trees contained significantly

more spiders in August
than non-herbicide-
treated trees. There were
no significant differences
earlier and later in the
season.

Lack of any difference
between herbicide- and
non-herbicide-treated
trees in the five second-
level IPM blocks might
have been due to the fact
that trees in these blocks
werematiire. Their cano-
pies reached well into the
vegetative region between
rows, diminishing the con-
trast between herbicide
and non-herbicide treat-
ments.

In general, it can be
concluded that no nega-
tive effect of herbicide
treatment on numbers of
spiders per tree has been
demonstrated by these
data. Among smaller
trees there may be a slight
positive effect. Perhaps
when an understory cover
exists directly beneath the
trees, spiders may forage
there for prey and be di-
verted away from the
trees. They may move back into the tree cano-
pies when there are more insect prey to be foimd
there than in the ground cover.

Conclusions

Spiders were found to be significantly more
abundant in second-level than in first-level IPM
blocks. This result suggests that elimination of
insecticide use after early or mid-June allows an
increase in population of at least one group of
natural enemies. High toxicity of broad-spec-
trum insecticides to spiders, as revealed in our
laboratory tests, supports this suggestion, £is do
findings of Mansour et al. (1980), Madsen and

Fruit Notes, Winter, 1993

Madsen (1982), and Bostonian et al. (1984) and
other authors.

The decreased number of spiders in first-
level IPM blocks may have been due not only to
direct contact toxicity of insecticide but also to
insecticide acting as a repellant to spiders, tox-
icity to spiders of prey feeding on insecticide-
treated plant material, lack of prey insects (as a
result of prey being killed or driven away by
pesticide), destruction of webs by turbulence
created by spraying, or a combination of these
and other factors.

Several questions stiU remain to be an-
swered. One of them is whether or not the
increased number of spiders in second-level IPM
blocks is great enough to contribute signifi-
cantly to the control of foliar pests. Can spiders
prey effectively on leafminers, leafhoppers, and
mites? Will they eat enough of such pests to
make a difference? We plan to address these
questions in the near futiu-e.

Acknowledgements

This project was funded by the Massachu-
setts Society for Promoting Agriculture, the
USDA Northeast Regional IPM Competitive
Grants Program, and State/Federal IPM funds.

We gratefully acknowledge this funding. We are
grateful to the following growers for their par-
ticipation and support: Dana Clark, Dave Chan-
dler, Dick Gilmore, Tony Lincoln, Wayne Rice,
and Joe Sincuk.

Literature Cited

Bostonian, N.J., CD. Dondale, M.R. Binns, D.
Pitre. 1984. Effects of pesticide use on spiders
(Araneae) in Quebec apple orchards. Canadian
Entomologist 116:663-675.

Madsen, H.F. and B.J. Madsen. 1982. Popula-
tions of beneficial and pest arthropods in an
organic and a pesticide treated apple orchard in
British Columbia. Canadian Entomologist
114:1083-1088.

Mansour, F., D. Rosen, and A. Sulov. 1980. A
survey of spider populations (Araneae) in
sprayed and unsprayed apple orchards in Israel
and their ability to feed on larvae of Spodoptera
littoralis (Boisd.). Acta Oecologica: Oecol.
Applic. 1:189-197.

Riechert,S.E. and L. Bishop. 1990. Prey control
by an assemblage of generalist predators: spi-
ders in garden test systems. Ecology 71:1441-
1450.

•^ ^JV •t» ^JV ^{f

^ ^ rfi rf» #Y*

Fruit Notes, Winter, 1993

Apple Integrated Pest Management
in 1992: Insects and Mites in
Second-level Orchard Blocks

Margaret Christie, Ronald Prokopy, Kathleen Leahy, Jennifer Mason,

Andrea Pelosi, and L. Kate White

Department of Entomology, University of Massachusetts

Last spring, in Fruit Notes [57(2):5-13], we
reported results of oiir first year of second-level
IPM trials in Massachusetts apple orchards.
Under second-level IPM, orchard management
is integrated across all classes of pests: insects,
mites, diseases, weeds, and vertebrates, rather
than focusing on a single type of pest. Here, we
report results of the second year of second- level
IPM trials on insects and mites in commercial
Massachusetts orchards.

Insect and mite management under second-
level IPM practices requires appUcation of three
to four selective insecticide sprays fi-om April to
early June to manage tarnished plant bug
(TPB), European apple sawfly (EAS), plum

curculio (PC), green fruitworm (GFW), the first
generations of codling moth (CM), lesser
appleworm (LAW), leafminer (LM), and leaf-
hopper (LH). Insecticide application to the inte-
rior of the block ceases after the final plum
ctu"cuho spray in early June, allowing natural
populations of predatory insects and parasitoids
to increase to levels we hope will be sufficient to
provide control of summer populations of foliar
pests. In full second-level IPM blocks, apple
maggot flies (AMF) are controlled by perimeter
interception traps. In transitional second-level
blocks, use of AMF interception traps is replaced
by perimeter row spraying with Guthion"™ or
Imidan"™ every three weeks beginning in early

Table 1. Average percent injury by early-season insect pests in second-level eind
first-level IPM blocks in 1992.*

Type of block

TPB

EAS

GFW

Total

Full second-level 1.5 a 0.1 a 0.1a 0.0 a 1.7 a

First-level 2.3 a 0.1 a 0.1 a <0.1 a 2.5 a

Transitional second-level 1.1 a 0.5 a 0.1 a 0.2 a 1.9 a

First-level 0.7 a 0.1 a 0.1 a 0.1 a 1.0 a

* Means in each couplet in each column followed by a different letter are
significantly different at odds of 19:1. Two hundred fruit of each of three cultivars
(Mcintosh, Cortland, and Delicious) were sampled at harvest. TPB = tarnished
plant bug; PC = plum curculio; EAS = European apple sawfly; GFW = green
fruitworm.

Fruit Notes, Winter, 1993

July. In both typ>es of blocks, removal of
unmanaged apple and pear trees within 100
yards of each block reduces immigration of CM
and LAW. Removal of drops after harvest dis-
courages buildup of within-orchard populations
ofAMF, CM, andLAW.

In early April of 1 99 1 , we selected six full and
six transitional second-level IPM test blocks of
six to nine acres each. In 1992, we replaced one
of the transitional blocks (which had been sold
and was no longer available to us) with a new
block on another farm. Each second-level block
was matched with a nearby control block which
weis managed by the grower, using first-level
IPM methods.

Early-season Fruit-injuring Pests

For control of arthropod pests active up to
early June, second-level IPM reUes on early-
season pesticide treatment based on monitor-
ing. We monitored each orchard weekly begin-

ning in mid-April, then biweekly from mid-Jime
through September. Five each of four types of
sticky traps were hung in each block to monitor
for TPB, LM, and EAS. We examined 100 or 200
leaves or terminals per block for LM, LH,
aphids, mites, and mite predators. Fruit were
examined both by IPM scouts and growers for
fresh PC injury. Based on this monitoring,
recommendations were made to the grower for
treatment of the experimental block.

In second-level IPM blocks (both fiill and
transitional) in 1992, combined injuries from
early-season fruit pests were simUsu" to those in
nearby first-level IPM (grower control) blocks.
In both first- and second-level IPM blocks, TPB
caused the greatest amount of injiuy, followed
by PC, EAS, and GFW (Table 1). Early season
insecticide use was similar in both types of
blocks, probably because both types were man-
aged through identical first-level IPM tech-
niques (Table 2). Injury by these early-season
pests was lower in 1992 than in 1991.

Table 2. Dosage equivalent

s (spray

events

in parentheses) of

insecticides and acaricides

used in second-level and first-level IPM blocks in 1992.*

Fruit pests

Mites

Before

After

mid-

Other

Type of block

June

Oil

miticides

ABLM

Total

Full

second-level

2.4

0.0

0.9

0.0

0.2

1.1

4.6

(4.0)

(0.0)

(1.8)

(0.0)

(0.2)

(1.0)

(7.0)

First-level

2.8

2.0

1.1

0.1

0.0

0.4

6.4

(3.8)

(2.2)

(1.8)

(0.2)

(0.0)

(0.5)

(8.5)

Transitional

second-level

2.7

0.7

1.2

0.3

0.0

1.0

5.9

(3.4)

(2.6)

(2.0)

(0.2)

(0.0)

(1.0)

(9.2)

First-level

3.3

3.1

1.3

1.1

0.0

0.5

9.3

(3.6)

(3.2)

(2.0)

(1.0)

(0.0)

(0.6)

(10.4)

* LH = leafhopper; ABLM

= apple

blotch leafminer.

Fruit Notes, Winter, 1993

Table 3. Season-long apple maggot fly (AMF) injury and trap captures in second-level
IPM blocks and first-level IPM blocks in 1992.*

Interior

Perimeter

% AMF

monitoring

Interception

injury

trap

to finiit

captures

Type of block

at harvest

per trap

per block

Full second-level

0.4 a

9.0 a

16.2 a

2430

First-level

0.1 a

6.9 a

14.4 a

Transitional second-level

0.2 a

3.5 a

5.9 a

„

First-level

0.1 a

3.7 a

5.6 a

—

* Means in each couplet in each column followed by a different letter are significantly
different at odds of 19:1. Two hundred finiit of each of three cultivars (Mcintosh,
Cortland, and Delicious) and two hundred border row fruit of mixed cultivars were
sampled at harvest.

Table 4. Fruit injury by codling moth (CM), leafrollers (LR), lesser
appleworms (LAW), and San Jose scale (SJS) in second-level and first-
level IPM blocks in 1992.*

Type of block

LAW

SJS

Full second-level
First-level

Transitional second-level
First-level

<0.1 a

0.2

0.0

<0.1 a

0.1

0.0

0.0 a

0.2

0.0

0.0 a

<0.1

0.0

* Means in each couplet in each column followed by a different letter
are significantly different at odds of 19:1. Two hundred fniit of each
of three cultivars (Mcintosh, Cortland, and Delicious) were sampled
at harvest, and for CM and LR and additional two hundred border-
row fruit of mixed cultivars were sampled at harvest.

Fruit Notes, Winter, 1993

Summer Fruit-injuring Pests:
Full Second-level IPM

Odor-baited sticky red spheres were hung
every five yards on perimeter apple trees of each
full second-level experimental block to intercept
immigrating AMF. These were baited with both
butyl hexanoate, a synthetic fi-uit odor deployed
in polyethylene vials, and ammonivun acetate, a
sjTithetic food odor released through a Consep™
membrane.

Interception trap captures averaged 2430 in
the six full second-level blocks, indicating that
AMF pressure was moderate in 1992. In 1991,
trap captures averaged 3562 in three blocks in
which traps were baited with both food and firuit
odor. Captures ofAMF on four interior unbEii ted
monitoring traps (indicative of AMF penetra-
tion into the block interior) were statistically
similar in second-level blocks and in nearby
first-level blocks. AMF injury to firuit at harvest
in second-level blocks was similar to that in
nearby first-level blocks (Table 3). One second-
level block, however, had 8% injury to Cortlands
in mid-September. The nearby first-level block
had no Cortlands , and all the Mcintosh had been
picked, so no comparison was available.

The second year of use of both butyl
hexanoate and ammonivim acetate (or carbon-
ate) to bait the AMF interception traps indicates
that this double-odor strategy may be very effec-
tive in large blocks. We ehminated the problem
of quick loss of ammonia by replacing polyethyl-
ene vials with slow release membranes. Tests
performed in our laboratory showed that flies
continue to be attracted to these membranes
even afler they have been in the field for several
months. Tests also indicated, however, that
fewer flies approached the trap if the membrane
flapped loosely in the wind. In addition, traps
may require more fi-equent cleaning than we
had previously thought, especially if the double-
odor trapping procedure results in the capture of
additional non-target insects. In 1992, we
cleaned our traps once a month, but in one
orchard, trap captures during a one-month pe-
riod were 271% higher on traps which were
cleaned of all insects than on those which were
not cleaned thoroughly, indicating that as in-

sects build up on the traps, trap captures de-
crease. In high-pressure situations, more fre-
quent trap cleaning may be necessary if AMF
are to be captured effectively.

Fruit injury by CM averaged less than 0.1%
in both block types for the second year.
LeafroUer (LR) injury averaged 0.2% in fuU
second-level blocks for the second year, and was
0.1% in nearby first-level blocks (Table 4). We
will continue to monitor carefiilly for leafrollers
because of concern that leafi-oller populations
may grow in blocks in which the interior is not
sprayed afler early or mid-June. No LAW or San
Jose scale (SJS) injury was found (Table 4).

No insecticides were apphed in second-level
blocks after mid-Jime. In the companion first-
level blocks, growers applied an average of 2.0
dosage equivalents of pesticide after mid-June,
and sprayed the block an average of 2.2 times
(Table 2).

Summer Fruit-injuring Pests:
Transitional Second-level IPM

Every three weeks after early June, i)erim-
eter row apple trees in transitional second-level
blocks were treated with insecticide to control
AMF. The block interior remained firee of insec-
ticide after early June. AMF injury averaged
0.2% in transitional second-level blocks and
0.1% in the nearby first-level blocks, slightly
lower in both cases than in 1991. On average,
3.5 AMF were captured on unbaited interior
monitoring traps in transitional second-level
blocks and 3.7 in first-level blocks, indicating
that in most cases relatively few AMF pen-
etrated into the orchard interior (Table 3). In-
secticide use after mid- June was reduced signifi-
cantly in transitional second-level blocks com-
pared to first-level blocks because apphcations
were made only to the block perimeter. Total
dosage equivalents of insecticide applied
against fi-uit pests afler mid-June averaged 0.7
in transitional second-level blocks and 3.1 in
first-level blocks. Growers also sprayed transi-
tional second-level blocks slightly less fre-
quently (Table 2).

Unmanaged apple and pear trees were re-
moved fi"om within 100 yards of the six transi-

Fruit Notes, Winter, 1993

Table 5. Peak levels of mites and mite predators in second-level and first-
level IPM blocks in 1992.*

Mite presence (% of leaves)

Type of block

ERM+TSM

Ratio of
ERM+TSM to Af

Full second-level 43.2 a
First-level 42.5 a

Transitional second-level 25.7 a
First-level 20.3 a

1.5 a
2.7 a

0.5 a
1.0 a

3.7 a
0.9 a

0.4 a
0.7 a

29:1
16:1

51:1
20:1

* Means in each couplet in each column followed by a different letter are
significantly different at odds of 19:1. ERM = European red mite; TSM
= two-spotted mite; Af = Amblysieus fallacis; YM = yellow mite.

Table 6. Foliar insect pest peak population and injury levels in second-level and first-level
blocks in 1992.*

Type of

PLH

WALK

block

PLH

injury

WALK

injury

ABLM

GAA

GAAP

WAA

Full

second-level

11.2 a

15.0 a

13.8 a

0.3 a

10.8 a

68.7 a

54.5 a

6.2 a

First-level

2.3 b

6.3 a

10.6 a

3.4 a

13.6 a

69.5 a

44.3 a

3.3 a

Transitional

second-level

7.2 a

4.5 a

6.1 a

9.3 a

10.8 a

77.3 a

55.3 a

8.2 a

First-level

0.5 b

0.5 a

1.1 a

0.4 a

11.8 a

65.3 a

57.0 a

11.0 a

* Means in each couplet in each column followed by a different letter are significantly
different at odds of 19:1. PLH = potato leafhopper, WALH = white apple leaftiopper;
ABLM = apple blotch leafminer; WAA = wooly apple aphid; GAA = green apple aphid;
GAAP = green apple aphid predators: cecidomyiids and syrphids. Data for PLH, PLH
injury, and WALH is in terms of percent of terminals examined. Data for WALH is in
terms of percent of fruit examined at harvest. Data for ABLM is in terms of the average
number of mines per 100 leaves. Data for GAA, GAAP, and WAA is in terms of the
percent of watersprouts examined.

Fruit Notes, Winter, 1993

tional second-level blocks. No CM injury was
seen in the transitional second-level blocks or
their companion first-level blocks. LR injury
was sUghtly, but not significantly higher in the
transitional second-level blocks than in the first-
level blocks. LR injury in transitional second-
level blocks was no higher in 1992 than in 1991.
No sampled fi-uit in either block were damaged
by SJS or LAW (Table 4).

Foliar Pests and Predators:
Full Second-level IPM

In 1991, we reported season-long average
population levels of fohar pests; this year we
noted their p>eak populations in an efifort to
reflect damage more accurately. Cool and wet
summer weather helped to maintain low popu-
lations of fohar pests in most cases.

Mite popxilations remained low in most
cases, as were populations ofAmblysieusfallacis
predators, which were not seen in full second-
level blocks until late August, £md were never
present in numbers thought to be sufficient to
achieve biocontrol. Yellow mite predator popu-
lations were slightly higher in second-level than
in first-level blocks throughout the summer, but
their abiUty to control any but the lowest mite
populations is questionable (Table 5).

Another predator, Typhlodemus pyri, which
is present in orchards in Western New York, was
released in two second-level IPM blocks. Sam-
pling one month after release revealed high
numbers of these mite predators on release
trees. We wiU not know until 1993 whether or
not they survived the winter and spring and
successfully colonized the blocks.

Both full second-level and nearby first-level
blocks were treated with about one dosage
equivadent of oil (Table 2). No other miticide was
used in full second-level blocks, and only one
grower apphed miticide to a first-level block.

Potato leafhopper peak population levels on
terminals were higher in full second-level than
in first-level blocks. Potato leafhoppers infested
11% of sampled terminals in full second-level
blocks and 2% in nearby first-level blocks. Peak
potato leafhopper injury to terminals was 15%
in second-level and 6% in first-level blocks.

White apple leafhoppers infested 14% of
sampled terminals in second-level blocks and
11% in first-level blocks; however, injury to fi-uit
averaged only 0.3% in second-level blocks, ver-
sus 3.4% in first-level blocks (Table 6). Injury in
first-level blocks, however, was confined prima-
rily to one orchard. In August, we identified rose
leafhoppers in all t)T)es of orchard blocks, but
further study is needed to determine their im-
portance in Massachusetts orchards. Pesticide
was applied against leafhoppers in early June in
only one second-level block, which had a signifi-
cant late-season infestation in 1991 (Table 2).

Average peak leafininer population levels
were similar in the second-level blocks and first-
level blocks (Table 6). All of the six fiill second-
level blocks were treated with DimUin™ against
leafminers (Table 2). Leafininer population
levels throughout the summer confirmed our
previous conclusion that apphcation of DimUin
against the overwintering generation of
leafininer adults, when indicated by trap cap-
tures, is the most effective and least invasive
technique for their control. Treatment with
Dimihn is preferable to use of other materials
which are harsher on beneficial insects and
mites. Dimilin was not available for vise in first-
level blocks, and few growers chose to treat
leafminers in those blocks. If registered, Dimilin
will be a good option for control of leafminers
without serious disruption of beneficials. We
chose to apply it before bloom so that it did not
affect leafi:x)ller and codling moth populations,
which we are trjdng to study in the absence of
insecticide use after mid-June. If registered,
Dimilin could be used later in the season after
first-generation mines have appeared, allowing
growers to avoid its use in years in which it may
not be needed.

In other articles, we provide data indicating
that predacious spiders are significantly more
abundant late in the growing season in second-
level blocks than in first-level IPM blocks, and
that some of these spiders feed on leafininer
larvae inside mines as well as on leafhopper
nymphs.

Green apple aphid (GAA) populations were
almost the same in the two types of blocks. At
their peak, aphids infested 69% of sampled

Fruit Notes, Winter, 1993

terminals in full second-level blocks and 70% in
nearby first-level blocks. Two aphid predators,
sjrrphid and cecidomyiid flies, were slightly
more prevalent in second-level blocks than in
first-level blocks. These high levels indicate
that predators achieved control of GAA in both
second-level and first- level IPM blocks. Infesta-
tion of terminals by wooly apple aphid (WAA)
was similar in second-level and first-level
blocks, but in both types of blocks WAA popula-
tions were lower in 1992 than in 1991 (Table 6).

Foliar Pests and Predators:
Transitional Second-level IPM

Very few Amblysieus fallacis predatory
mites were seen in transitional second-level or
nearby first-level blocks luitU September (Table
5). Mite levels in most cases remained low,
although one grower had European red mite
populations in his transitional second-level
block sufficient to warrant treatment with a
miticide in mid-summer (Table 2). Mid-season
miticides were applied in four of the six first-
level blocks, with an average of 1.1 dosage
equivalents of miticide per block (Table 2).

Potato leafhopper infestation levels on ter-
minals averaged higher in transitional second-
level blocks than in nearby first-level blocks. In
transitional second-level blocks, white apple
leafhoppers infested 6% and potato leaflioppers
7% of terminals at their peak, while in nearby
first-level blocks, both white apple leafhopper
and potato leafhopper populations peaked at
about 1% of terminals infested. White apple
leafhopper injury to frmt at harvest was statis-
tically simUar in transitioned second-level and
first-level blocks, and potato leaQiopper injury
also was statistically similar in transitioned
second-level and first-level blocks (Table 6). In
no case did these insects cause serious problems
for growers.

All six transitional second-level blocks were
treated with DimiUn against first generation
leafminers. Only two growers treated their
first-level blocks for leafminers (Table 2). Peak
numbers of mines on 100 leaves averaged 10.8
in transitional second-level blocks and 11.8 in
first-level blocks, considerably lower in both

blocks than in 1991 (Table 6).

GAA populations were higher in 1992 than
in 1991. At their peak, they infested an average
of 77% of terminals in transitional second-level
blocks and 65% of terminals in nearby first-level
blocks. Predator populations were higher this
year as well; their populations peaked at an
average of 55% of terminals infested in transi-
tional second-level blocks and 57% of terminals
in first-level blocks. In both cases predators
were adequate to provide control of aphid pests.
Similar numbers of terminals in the transitional
second-level blocks and in first-level blocks were
infested with wooly apple aphids (Table 6).

Conclusions

We continue to be pleased with the success of
implementation of second-level IPM for apple
insects and mites in six- to nine-acre blocks in
commercial orchards. In 1992, full second-level
IPM blocks received 28% less total dosage
equivalents of insecticide and miticide and 18%
fewer total spray events for insects and mites
than first-level IPM blocks. Excluding pre-
bloom sprays of oil (non-toxic in the environ-
ment), dosage equivalents were reduced 30%
and spray events were reduced 22%. Despite
this difference, total firut injury by insects was
similar in full second-level and first-level IPM
blocks, and peak populations of foUar pests were
not different, except for leafhoppers.

Early season fruit injury from PC, TPB,
EAS, and GFW was low in all cases, as was finiit
injury by CM, LR, LAW, and SJS. GAA were
controlled by predators in both second-level and
first-level blocks. We continue to work toward
gaining registration of Dimilin, which provides
good control of leafminers without disrupting
beneficial parasites and predators.

Transitional second-level IPM appears to be
an effective reduced-spray management pro-
gram for insect and mite pests in commercial
orchards. In 1992, transitional second-level
IPM blocks received 37% less total dosage
equivalents of insecticide and miticide and 12%
fewer total spray events for insects and mites
than first-level IPM blocks. Total fruit injury by
insects did, however, average sUghtly but not

Fruit Notes, Winter, 1993

significantly higher in transitional second-level
blocks than in first-level blocks. Peak popula-
tions of foUar pests were Uttle different, except
for leaflioppers, which were somewhat more
abundant in the transitional second-level
blocks.

For 1991 and 1992, combined, transitional
second-level IPM blocks received about 17%
more insecticide and miticide and 23% more
spray events than full second-level IPM blocks.
Insect-caused fi*uit injury averaged over both
years was virtually identical in full and transi-
tional second-level blocks.

Our main concern with the benefits of tran-
sitional second-level IPM over the long-term Ues
with the potential buildup of AMF from infested
fallen drops not removed at harvest. The odor
baits employed with the interception traps im-
der full second-level IPM can attract these AMF.
A second concern with the long-term benefits of
transitional second- level IPM Hes with potential
negative effects of perimeter-row sprays on im-
migration of beneficial predators and parasites.
Two more years of planned comparison of full
second-level IPM vs. transitional second-level
IPM vs. first-level IPM orchard practices should
provide more insight into the benefits and costs
of each practice.

A second year of trials has not answered all
of our questions about two foUar pests, mites
and leafhoppers. Although mites were rarely a
problem in this wet, cool summer, predator
populations were low even where pest mites
existed in numbers sufficient to support them.
We need to learn more about overwintering
locations of mite predators and about the exact
identity of predators in Massachusetts or-
chgirds. Further monitoring of the newly-re-
leased predator, Typhlodemus pyri, will help us
to determine if release of this pesticide-resistant
predator could help to control pest mites in
Massachusetts orchards. We will continue to
study the role of spiders in pre3dng on leafinLners
in mines and on leafhopper njrmphs.

In our judgement, the key to grower adop-
tion of second- level IPM practices for insects and
mites hes in availabihty of a low-cost approach
to interception trapping of AMF. At present,
costs of labor and materials to employ odor-

baited sticky red spheres exceeds by nearly
twofold the cost of applying insecticide sprays
against AMF and other summer finiit-injuring
insects. The fi:^quent cleaning of sticky traps
necessary to provide an effective capturing sur-
face is a major component of the cost of this
system. We believe that development of pesti-
cide-treated spheres (now in progress) as a sub-
stitute for sticky spheres will provide a cost-
effective approach to using interception traps
for this insect.

Even if we assume that a pesticide-treated
sphere interception trap system for AMF will be
no more costly than applying insecticide after
mid-Jime, why should a grower want to switch
from an insecticide-based first-level IPM ap-
proach? We believe there are at least four
reasons for doing so: ( 1) saving money on sprays
against foliar pests by allowing beneficial natu-
ral enemies to build up and provide control in the
absence of pesticide use; (2) reducing the UkeU-
hood that foHar pests will develop resistance to
pesticides, thereby preserving the long-term ef-
fectiveness of these pesticides; (3) reducing pes-
ticide intrusions on neighbors or the environ-
ment adjacent to orchards; and (4) greatly re-
ducing or eliminating pesticide residues on finait
at harvest. For some growers, these potential
advantages could be large.

Acknowledgements

This project was funded by the Massachu-
setts Society for Promoting Agriculture, the
USDA Northeast Regional IPM Competitive
IPM Grants Program, State/Federal IPM funds,
and the Northeast Region Sustainable Agricul-
ture Research and Education Program (for-
merly LISA). We gratefully acknowledge this
funding. We are also grateful for the participa-
tion and support of the following growers: Bill
Broderick, Dave Chandler, Dana Clark, Dick,
Greg, and Kevin Gilmore, Tony Lincoln, Jesse
and Wayne Rice, Joe Sincuk, Dave Shearer, Tim
Smith, £md Barry and Bud Wiles, and for the
scouting assistance of Ryan Elliott, Kathy
Hickey, James Gamble, £md Peter Winnick of
the Department of Plant Pathology.

Fruit Notes, Winter, 1993

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

-0

SERIAL SECTION

UNIV. OF MASSACHUSEHS LIBRARY
AMHERST, MA 01003

Account No. 3-20685

ISSN 0427-6906

Fruit Notes

Prepared by the Department of Plant & Soil Sciences. j zsi j y Q F M A S S

University of Massachusetts Cooperative Extension System.

United States Department of Agriculture, and Massachusetts Counties Cooperating.

HP A P \^

APR -6 S3

Eklitors: Wesley R. Autio and William J. Bramlage

AJr(/yan shomhtos
£661 ZO -^w

Volume 58. Number 2
SPRING ISSUE, 1993

Table of Contents

Spiders That Feed on Leafhoppers
and Leafminer Larvae

Apple Growing in China

Evaluation of New Apple Cultivars

Implementation of the MARYBLYT Model for Fire Blight Control

Fish Hydrolysate Fertilizer Should Not Be Applied Foliarly to Apple

Comparative Effects of Margosan-O (Neem Extract)
and Imidan on Plum Curculio and Apple Maggot

Orchard Mineral Nutrition: Ground-applied vs. Foliar-applied Fertilizers

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.

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 use* niggetled in thii publicaiion are contingent upon continued regitmtion. Theie chemicali should
be uERTY
DAMAGE.

Issued by the University of Massachusetts Cooperative Ejtension System, Robert G. Helgesen, 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.

Spiders That Feed on Leafhoppers
and Leafminer Larvae

Joanna \^sniewska and Ronald Prokopy

Department of Entomology, University of Massachusetts

Recently in Fruit Notes [58(1): 20-23], we
showed that spiders were signiRcantly more abun-
dant in second-level than in first-level IPM blocks.
We concluded by asking whether or not increased
numbers of spiders in second-level blocks were great
enough to contribute to the control of foliar pests.
Here, we describe 1992 laboratory studies in which
some of the most abundant types of spiders collected
in second-level blocks were offered white apple leaf-
hopper nymphs and adults and apple blotch
leafminer larvae as potential prey.

Each spider was placed in a waxed paper cup
(four inches tall by three inches in diameter) with a
plastic lid. Into each cup we introduced an apple leaf
kept turgid by placing its stem in water. The leaf
harbored one tissue-feeding (late instar) leafminer
larva and two
leafhopper
nymphs (or
one nymph
and one

adult). The
test lasted for
24 hours. Re-
sults

are
in

Table 1. Laboratory tests of orchard-collected spiders feeding on
potential prey.

Family
of spiders

Number
tested

a cat stalks a mouse before the final pounce. They
may even capture it in mid air and then climb back
to the leaf fVom which they have jumped using a
piece of silk previously attached to that leaf. Salticid
spiders are successful nine times out often. They are
active only during the day.

Of the Araneid spiders, 28% fed on leafhoppers.
Most of these spiders were smaU immature individu-
als otAraniella displicatta, which are found com-
monly on terminals of apple tree branches. They
build tiny orb webs stretching across dorsal surfaces
of leaves. Their webs are found at night and during
the day. These spiders prayed mostly on the adult
leafhoppers which got caught in their webs.

Only members of the Anyphaenid family fed on
leafminers. Predation on leafminer larvae took

place by 90%
of the

Anyphaenid
spiders
tested. In all
the

Spiders that

fed on

leafhoppers (%)

Spiders that fed

on leafminer

larvae (%)

Philodromidae

Araneidae

Salticidae

Anyphaenidae

Thomisidae

27
22
11
10

given
Table 1.

Of the
five families
of spiders ex-

a m i n e d , _^^^^^^___^^^^^^_^^^^^_
members of

three families fed on leafhoppers: Anyphaenidae
(hunting spiders), Salticidae (jumping spiders), and
Araneidae (orb web spiders). The Anaphyenid spi-
ders were the most voracious, as 100% of the tested
individuals fed on leafhopper nymphs and adults
(their behavior will be described later in conjunction
with predation on leafminers).

Of the Salticid spiders, 36% fed on leafhoppers.
These visually oriented spiders are often observed
running around on leaves and branches moving
their heads from side to side as they search for prey.
Once they locate a prey insect, they stalk it much as

100

cases

mines were
opened from
the underside
of the leaf and
the larvae
were missing.
It was not
possible to
identify the
specific spe-
cies, because they all were immature. But our best
guess is that 9 of the 10 individuals tested were
Aysha gracillis. These hunting spiders are common
on foliage. They forage for prey mostly by sensing
vibrations on leaves and (possibly) branches. They
were often found foraging at night but they may also
be active during the day.

The type of leafminer predation observed in this
experiment is characterized by a very specific mark
left on the leaves. For this reason it may be possible
to quantify predation by Anyphaenid spiders in the
field by counting the leaves which have the signs of

Fruit Notes, Spring, 1993

predation and those which do not, provided that
observations are made soon after predation. We
conducted a preliminary study to quantify predation
in this way.

In one of the three orchards where spiders were
collected for use in the feeding test (University of
Massachusetts Horticultural Research Center,
Belchertown), we inspected 600 randomly selected
leaves from 60 different apple trees on October 7. Of
these leaves, 228 had leafrniner mines, 20% of which
appeared damaged due to spider predation. In other
words, 20% of the leafrniner larvae in the orchard in
late September may have been prayed upon by
Anyphaenid spiders. To compare this finding with
what may be taking place in an orchard that has
more spiders, on November 5, we inspected 169
randomly selected leaves containing leafrniner lar-
vae on four apple trees in an abandoned apple
orchard (Orchard Hill area at the University of
Massachusetts at Amherst). Of these mines, 37%
appeared damaged due to predation of Anyphaenid
spiders.

Even though these findings are very prelimi-
nary, they suggest that spiders of at least three
families exhibiting different foragingstrategies may
be able to prey upon some of the most troublesome
foliar pests of apple orchards. Aysha species of the
family Anyphaenidae, in particular, may play a

beneficial role in leafhopper and leafrniner control.
In 1993, we plan to conduct feeding tests on more
spider species commonly found in second-level or-
chard blocks and more individuals of each species.
We also plan to conduct these tests under more
natural conditions than the highly confining condi-
tions of the laboratory used in 1992. We also hope to
investigate the relationship between spiders feeding
on leafminers and beneficial parasitoids feeding on
leafminers. For example, it would be important to
know if (and how much) spiders are likely to prey
upon parasitized leafminers. Are spiders beneficial
if they selectively extract parasitized leafrniner lar-
vae but leave unparasitized larvae alone? HopefuUy
our planned 1993 research wUI provide greater
insight into the value of spiders as biological control
agents of foliar apple pests.

Acknowledgments

This project was funded by the Massachusetts
Society for Promoting Agriculture, the USDA
Northeast Regional IPM Competitive Grant Pro-
gram, and State/Federal IPM funds. We gratefiilly
acknowledge this funding. We are grateful to the
following growers for their participation and sup-
port: Dana Clark, Dave Chandler, Dick Gilmore,
Tony Lincoln, Wayne Rice, and Joe Sincuk.

%f^ •S^ mS^ ^# •S^

0^ rj% w^ r{% 0^

Apple Growing in China

Ronald J. Prokopy, M^lliam M. Coli, and Jian Jun Duan
Department of Entomology, University of Massachusetts

In Jiine of 1992, we had the wonderful oppor-
tunity of visiting several apple orchards in vari-
ous parts of east-central China in combination
with a trip to the International Congress of
Entomology in Bejing. We thought it might be
interesting to convey some of the things that
impressed us.

First of all, a bit of history. According to our
Chinese colleagues, apples have been grown in
China for at least 2000 years. Apples are planted
on nearly four million acres in China, equal to

about one-third of all acreage devoted to horti-
cultural crops. China is roughly the size and
shape of the continental United State. This
means that a greater percent of the land area of
China is devoted to apples than in the United
States (which has about 500,000 acres in
apples). Although production per acre is not
nearly as great in China as in the United States,
total production is about the same: 230 million
bushels a year. Many Chinese orchards are
newly planted, thus partly accoiinting for low

Fruit Notes, Spring, 1993

average yield. In the United States, we produce
about one bushel for every person. In China,
production is about one bushel for every five
people. Because living standards are improving
very rapidly in China, there is a potential mar-
ket for firuit appearing from either a major
increase in Chinese apple production or mcgor
importation of apples fi:t)m abroad. The most
popular cxiltivars in China are DeUdous and
Golden Delicious and more recently Fuji and
"Red Snake."

Presently, most orchards are owned by com-
mimes. Each family in the commune is entitled
to lease about three acres of land firom the
commime and farm it in any way the family sees
fit. The family can keep whatever it earns. All
the trees that we saw were dwarf or semi-dwarf.
One of the fascinating things to us was that
every 20 rows or so were managed by a different
family and often in a different way. So your
immediate neighbor's horticultural practices
could have a very strong influence on your crop,
for better or for worse.

Another fascinating thing was the absence
of £my vegetation whatsoever beneath the trees
but the lush vegetation of other crops grown in
the allesrways between rows. These crops in-
cluded peanuts, cotton, strawberries, melons,
com, and several others. All vegetation beneath
trees was removed by stout Chinese hoes in
order to reduce the drain of vegetation on water
and nutrients. We wondered how it was fmssible
to run tractors and sprayers down the allejrways
without crushing the other crops. The answer
was: tractors and motorized sprayers are few
and far between. Nearly all the sprajdng is done
by attaching a hose 30 yards or so in length to an
outlet fi*om an imderground pipe that supplies
the spray mixtvire fi-om a central mixing point.
The farmer simply sprays all trees within reach
of the hose before picking up and moving on to
the next attachment site. Some sprajdng is also
done with backpack sprayers and "bucket-
pumps." In this way there is no harm to crops in
the alleyways (other than pesticide drift). Most
applicators did not seem concerned about poten-
tial dangers fi*om pesticide. They wore no gloves,
masks or other protection, much the way it was
in the United States in the 1940's!

Nearly all of the 20 or so orchards that we

saw were maintained in excellent condition.
Tree structure was particularly good, generally
better than the average Massachusetts block of
dwarf trees. It w£is mainly based on a three-
tiered, central-leader tree pruning and Umb
training system. Advice on tree planting, tree
training, fertiUzation, and pest control is given
to all apple-growing members of a commune at
least four times a year through visits by exten-
sion pomologists from the Division of Fruit and
Forestry. We were told that the average family
sprays about eight times a year, mainly against
mites, aphids, moth larvae, powdery mildew,
scab, and canker. From our perspective, tree
foUar growth was very lush (probably too lush).
So it was not siuprising that mites and aphids
took a strong liking to it. Maybe the lack of
competition for nutrients in the absence of
understory plants was too much of a good thing.
The high upright growth of many trees was at
least partly due to the common practice of t)dng
branches down to horizontal or below horizontal
positions, which then results in unnecessary
uprights. There was a great deal of interest in
biological control of mites and aphids but less
progress on this area than we ex{)ected.

We wondered how apples were stored and
sold aRer harvest. It turns out that cold storage
does not exist to any appreciable extent. The
fi-uit are trucked by the buyer to the local mar-
kets for immediate consumption. The storages
that do exist are mostly in undergroimd cellars
or in above-ground clay structures that are
periodicedly hosed with water for cooling.

Of all the many surprising things we encoun-
tered, perhaps the most siurprising of all was the
intent interest by the governor of a coimty of
about two million people in the possibility of
making applejuiceorcider. She questioned us at
length about how cider was made in the United
States. It seems that apples have never been
iised in this way in China. She said that her
people would love to have apple cider if they
knew a good way to make it. What an opportu-
nity for marketing low cost hand-operated cider
presses.

We were treated royally with unexcelled
hospitality (including 35-course Ivmches) wher-
ever we went. It was indeed an eye-opening,
unforgettable experience.

Fruit Notes, Spring, 1993

Evaluation of New Apple Cultivars

Duane W. Greene and Wesley R. Autio

Department of Plant & Soil Sciences, University of Massachusetts

In recent years, apple cultivars originating pri-
marily from New Zealand, Australia, or Japan have
gained considerable consumer acceptance in the
market place. Prices received for these new culti-
vars have exceeded those for the traditionally-grown
apples. This differential has led to a new awareness
and a hei^tened interest in planting new apple
cultivars. Many new apples are under test but there
is a dilemma about which of these to plant. The
decisions are made somewhat easier now since there
are a number of good and legitimate choices avail-
able to growers.

About iive years ago we started planting some of
the most promising new cultivars and numbered
selections. Scion wood was obtained for propagating
trees from several countries and from various breed-
ing programs. During the 1992 season many of these
cultivars fruited. This report presents evaluations
of some of these new cultivars.

Fruit evaluation started the first week in August
and continued weekly through the third week in
October. Where sufficient fruit were available, mul-
tiple harvests were made. Fruit on each harvest date
were evaluated in two ways. First, fruit were
weighed, counted, the diameter measured, and then
red color was estimated to the nearest 10% on red
coloring cultivars or on those yellow cultivars that
had a prominent red cheek. Flesh firmness and
soluble solids were measured. Fruit then were
evaluated visually and sensory characteristics were
judged on a specially prepared evaluation sheet
(Figure 1). Lines approximately 10 cm in length
were anchored at either end with descriptive terms.
In each category a line was drawn through the line
at a point that was judged to be appropriate for the
apple. For example, if the color was judged to be
neither dull nor bright a pencil mark was drawn half
way between the terms. The length of this was
measured from the zero point on the left and then
recorded in the blank. The numerical value given in
this instance would be 5.0. All other parameters
were eveiluated similarly and measured. A value of
6.5 is considered to be very good and a score of 7.5 or
greater is excellent. A summary of the taste, visual,
and laboratory evaluations of selected parameters
are presented in Tables 1 and 2. Cultivars are listed
in order of the harvest date at which they were

considered best.

A log was kept and notes were taken for each
cultivar at each harvest date. Below, listed by
alphabetical order, are summaries of observation
made on many of the cultivars evaluated. The star
rating system recommended by the Pacific North-
west Fruit Tester's Association was used.

*M*

**** A cultivar tested in many areas and
found worthy as a good risk for commer-
cial recommendation.
A very promising cultivar but with some
possible limiting factors.
A cultivar, new or old, worthy of testing
for today's changing apple world.

* A cultivar or strain that has been
through enough testing and/or commer-
cial trials to be classified as not worthy of
commercial recommendation.

T An upward-pointing arrow with a star
indicates increasing interest

i A downward-pointing arrow with a star
indicates decreasing or waning interest.

Akane (.***) continues to be one of the apple culti-
vars that we favor. It is a very attractive apple and
few apples in its season have the flavor that Akane
does. It must be allowed to stay on the tree long
enough to mellow. It is the most aromatic apple we
evaluated. A m^or fault is that it is a shy bearer.

Alkemene {**) is a yellow apple with a deep orange
cheek. It is somewhat russeted which detracts from
its overall attractiveness. It has a spicy, sprightly,
flowery taste. Flavor was rated quite high. A
problem is that it is competing with Gala, Elstar, and
Arlet. It may not be different enough or better
enough to compete successfully with these cultivars.
It is a disease-resistant cultivar, however, and this
characteristic may increase its appeal.

Ambitious (*) has fiTiited for three years. It is a very
late apple with too much competition from other
cultivars to succeed. It ripened properly in only one
of the three years. Fruit size is small. It is one of the
ugliest apples in our plot with only fair flavor. Fruit
are susceptible to Pseudomonas.

Fruit Notes, Spring, 1993

Cultivar

Visual and sensory evaluation:

Color

Attractiveness

Aroma

Skin

Crispness

Juiciness

Sweetness

Acidity

Starchiness

Astringency

Flavor

Desirable

Weight
Color

dull

dislike

none

tough

low

bland

low

dislike

Date

bright

intense

tender

high

tart

high

Flesh firmness
Soluble solids

Figure 1. Cultivar evaluation form.

ArkcharmP' AA-18 (**) is a very attractive light
cherry red apple with semiprominent lenticels. It
has a spicy taste, not sweet, flesh not too crisp, with
acidity quite high. Fruit were harvested over a two-
week period. Even when watercored, they still are
very acid. Arkcharm warrants further evaluation.

AA~44 (**t) is a large blotchy cherry red apple.
Flavor is good but not strong. It is equal to Paulared
in flavor and ripens slightly before Paulared. It
shows some tendency to drop. This cultivar war-
rants further evaluation.

AA-62 (*) looks somewhat like a Golden Delicious
and ripens at about the same time. The finish is
good, with no russeting; however, fruit show severe
bitter pit and Pseudomonas. Fruit have a good but
not an outstanding taste with an anise flavor. It is
more acid than Grolden Delicious. If it is not better

than Golden Delicious it may not have a future.

AA-63 (**) was a very pleasant early surprise. It has
speckled red skin, perhaps like an Early Mcintosh.
It £dso tastes like a very good early Mcintosh, with-
out the sharp astringent taste. It is smaU with a very
short shelf life. We rated it very high for color, flavor,
and overall. It is better than Sumac which ripens at
a similar time.

Arlet (**T) remains high on the new cultivar list
despite its three major faults: preharvest drop,
russet, and poor color. It received one of the highest
flavor rating. It has a good sugar-to-acid ratio that
tends to favor acid. It stores quite well and keeps it
taste for a long time. The greasiness that develops on
Arlet is quite different from that developing on other
apples, since it can be washed off. Even though it
feels greasy, internal condition can still be very good.

Fruit Notes, Spring, 1993

There is a very good relationship between develop-
ment of red color and drop. The quality of this apple
is too good to discard right now, even with its faults.

BC 9-17 (*) is a medium sized dull cherry red apple
with semiprominent lenticels. The flavor is not
strong, and when ripe it has a hint of perfume and
pineapple. It is a fairly good apple, but certainly not
outstanding.

BC 78-9-28 (*) is a medium sized, attractive red
apple. The skin is smooth and lightly striped. The
flesh is slightly chalky and the flavor is like licorice.
The very different taste makes it difficult to decide
whether or not we like it.

BC 8C-27-96 Sunrise i**i) is a very attractive
apple but when it develops outstanding red color, it
is too ripe. The flesh characteristics are outstanding.
It is crisp, juicy, and just feels wonderful. A major
weakness of this apple is that it has a very weak
apple flavor and the flavor that it does have is
acceptable but not outstanding. We do not rate
Sunrise very high.

BC 15-30 (*) is a large, light cherry red apple with
prominent brown lenticels. Even when ripe (Sep-
tember 1) acidity is high. It has a pronounced
pineapple flavor that is not totally related to
watercore. This apple was rated average for red
color, fairly high on attractiveness, and average for
taste and flavor. This fruit is neither outstanding
nor poor.

BC9P-14-32 (**t) was one of the pleasant surprises
this year. It is not very attractive because the cherry
red is not intense and there is considerable net-like
russeting. Fruit size is medium, flesh is yellowish-
white, flesh texture is good, and the sugar-to-acid
ratio is good. The taste and appearance is reminis-
cent of Arlet. This apple was rated among the
highest for flavor and overall desirable. It is a very
good apple.

BC 2-8 (*) is a very attractive red apple that re-
sembles Delicious; however, the beauty is only skin
deep. Even when very ripe fruit were tasted, the acid
level was almost off the scale. It is an attractive
apple with only fair to good quality. Fniit were
dropping on September 21.

BC 8M-15-10 (**T) was the second British Columbia
selection that we thought was truly outstanding.
This apple has blotchy pink-red color. Overall it is
not an attractive apple. The flesh is yellow with a
mild banana flavor. It is extremely crisp and juicy.

Unlike published reports, it does not remind us of
Fuji, but is more reminiscent of Braebum. As far as
taste, crispness, and juiciness are concerned, you
could not ask for a better apple. It is outstanding.

BC8B-1'^50(**) is a fairly attractive andfairly good
tasting apple. It looks like a Delicious and has cream
yellow flesh. Fruit are deep cherry red at the optimal
harvest date. The longer fruit stayed on the tree the
better it got, although flesh firmness and texture
were poor. The flavor of this apple is very complex:
fruity and tropical. Since the taste is different and
it improves with age, this cultivar may benefit from
a period of cold storage.

DIR 98T-486 (**) is a very attractive deep red apple
on a cream yellow ground color. The irregular
surface detracts somewhat from the appearance, but
still it was one of the most attractive to be evaluated
this year. Flavor improve with time on the tree.
Fruit harvested on October 5 were quite good but the
ground color indicated that the shelf life then would
be rather short. The fruit is very juicy, yellow-white
fleshed, and slightly tough skinned. It is so attrac-
tive, that based solely on appearance, it should be
looked at further.

BC 17-30 (**T) is a very attractive, dark-burgundy-
red apple of the Mcintosh type. The flavor is remi-
niscent of Mcintosh with Spartan overtones. Per-
haps it tastes most like Acey Mac. The flavor may be
a little bland but it is still a very good apple. Flesh
is white with a greenish tinge. The pedicle is long
and lenticels are semiprominent. This apple war-
rants further evaluation.

BC 8K-21-39 (**) is a fairly good apple with better
than average appearance. It is round to conic, has
yellowish-white flesh that is somewhat dry. Fruit
shows some russeting. Where the surface is red it is
attractive. The red looks muddy on the green-red
interface. The longer the fruit remained on the tree
the better it tastes.

BC 8C-6-62 (*) is a dark cherry-red apple with a
bumpy surface caused by raised lenticel. The flesh
is yellowish white. The flesh was so acid that it was
not possible to evaluate flavor effectively. This fruit
was about the most highly acid apple that we evalu-
ated this year. We were not impressed.

Bonza (*). This is the second year that we have
evaluated Bonza. It is somewhat attractive and red
color is good. The surface of the apple is not smooth,
the flesh is rather dry, and the flavor is acceptable
but not outstanding. We are not encouraged to

Fruit Notes, Spring, 1993

Table 1. Taste evaluation of apple

cultivars grown

at the L

niversity of Massachusetts Horticultural |

Research Center.

1992.

Red

Overall

Cultivar

Date

Attractiveness

color

Sweetness

Acidity

Flavor

desirable

AA63

Aug. 6

5.1

6.8

5.3

6.1

7.4

6.7

Sumac

Aug. 6

2.3

3.0

5.1

6.4

7.1

5.3

NY 66305-139

Aug. 6

3.6

2.2

1.8

9.0

3.3

2.4

BC 9-17

Aug. 11

4.5

4.0

8.8

6.5

5.0

Arkcharm (AA 18)

Aug. 17

7.9

6.5

2.7

8.0

5.3

5.1

Jerseymac

Aug. 17

5.5

6.7

5.6

4.8

6.2

5.9

BC 78-9-28

Aug. 17

6.9

6.5

5.3

5.0

4.8

BC 15-30

Aug. 17

4.8

5.0

2.4

7.9

4.4

4.0

Williams Pride

Aug. 20

5.6

6.4

4.5

4.8

6.1

6.2

Redfree

Aug. 20

8.4

8.8

5.2

5.5

7.6

7.4

OSU 31-19

Aug. 20

3.0

3.6

5.2

6.1

7.0

6.8

AA44

Aug. 24

5.5

5.9

5.1

7.8

5.7

5.8

Paulared

Aug. 24

6.3

6.4

2.3

6.9

5.0

5.3

BC 8C-27-96

Sept. 1

6.3

5.0

5.2

5.5

5.1

5.3

Sansa

Sept. 1

6.4

6.3

7.4

5.5

7.4

Nebuta

Sept. 1

6.5

7.0

5.5

6.7

5.1

5.3

BC 15-30

Sept. 1

5.7

5.2

8.8

5.1

4.0

Himekami

Sept. 8

7.0

3.3

8.5

4.1

3.9

Akane

Sept. 8

8.5

8.4

5.5

6.9

6.8

BC 9P- 14-32

Sept. 8

4.1

4.4

6.2

7.0

7.9

7.4

Dayton

Sept. 8

5.6

6.3

5.7

6.4

5.8

5.1

Ginger Gold

Sept. 14

8.0

...

6.5

6.2

5.8

7.4

Fiesta

Sept. 14

4.2

3.5

4.8

5.0

5.7

5.2

Tsugaru Homei

Sept. 14

5.2

5.0

8.1

4.8

6.3

Arlet

Sept. 14

4.7

5.6

7.0

7.5

6.5

Elstar

Sept. 14

4.5

4.4

3.2

8.1

4.7

4.6

NY 66305-289

Sept. 14

6.8

3.4

7.1

5.3

5.9

NY 74828-12

Sept. 21

6.7

6.8

3.4

7.3

5.5

5.8

Alkemene

Sept. 21

5.3

5.6

6.3

6.8

5.9

5.6

Honeycrisp

Sept. 21

2.9

3.5

6.8

5.2

6.3

5.2

BC2-8

Sept. 21

7.1

6.9

4.2

8.2

4.8

5.3

Shamrock

Sept. 28

4.8

—


Search: Advanced Search	UploadAnonymous User (login or join us)