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FRUIT
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 42 (No. 1)
JANUARY-FEBRUARY 1977

TABLE OF CONTENTS

Interregional Cooperative Research in Fruit Tree Viruses
and Aspects of Control Measures: Present and Future

When Should an Existing Orchard be Replaced

Cleaning the Weed Sprayer

A Substance that Deters Egglaying by Apple Maggot Flies

Supplement - Establishment and Management of Compact
Apple Trees (Part II) (6 pages)

INTERREGIONAL COOPERATIVE RESEARCH IN FRUIT TREE VIRUSES AND
ASPECTS OF CONTROL MEASURES: PRESENT AND FUTURE^

R.C. McCrum
Department of Botany and Plant Pathology
University of Maine

A few commercial nurseries conduct virus indexing programs in
regard to their propagating stocks and also maintain nuclear stock
blocks. Individual State Experiment Stations as well have for
several years cooperated in certification programs with commercial
nurseries in regard to Prunus tree fruit nursery plants. There is,
however, at the present no general U.S. recognized certification
or regulatory program for distribution of virus-indexed or virus-
free apple nursery stocks. In this respect, the U.S. orchardist
is not as fortunate as his European counterpart in receiving reli-
able virus-free materials. The European distribution of virus-free
material, handled through regulated programs, involving both re-
search and inspection agencies, results in great volumes of clean
budwood from the initial source which is built up and released to
the industry by the cooperating nurseries. Part of the problem in
the U.S. in not duplicating this accomplishment is the reluctance
of the American growers to set up a uniform, regulated approach for
handling virus- indexed trees. Also, because of our numerous and
separate fruit growing areas, there tends to be a larger diversity
in apple cultivars due to the different climatical aspects, grow-
ing seasons, temperature limiting factors, other pressing disease
pathogens, soil types, processing requirements and changing con-
sumer demands, each one a critical factor to specific area growers.
In addition to this, there is a rapid development of patented selec-
tions being offered to the trade.

In spite of these handicaps, there has been considerable prog-
ress in obtaining and using virus-clean apple trees and we must
realize that it is only 5 years since the first introduction and
distribution of the IR-2 program's virus-free apple stocks began.
We are just beginning to realize that our research findings and
dissemination of this knowledge, which has led to increased quar-
antine interest in regard to the import of pome fruit tree mater-
ial, signifies that the U.S. itself must also establish certifi-
cation criteria and procedures in order to export it's own nurs-
ery material to meet the expanding world competition.

There is little or no control on the shipping of virus-infec-
ted apple budwood or treesthroughout the United States. This has
in the past led to a high incidence and spread of latent viruses,
particularly in cases where new cultivars have been desired quickly,
in large amounts, and have been put on older, sometimes infected
stock trees for a fast buildup of material. Exchange of nursery
stocks among regions and nursery suppliers, without detailed inform-
ation as to original source and disease status, also helps to in-
crease the problem.

Part I appeared in Nov. -Dec, 1976 issue of Fruit Notes

With few exceptions, you pay your money and take your chances
in regard to infection with viruses when you purcliase tree stocks.
Progress is being made when nurseries start from original clean
source materials, but it will take several years until large numbers
are built up, particularly with patented varieties. In addition,
grower reluctance to pay premiums for certified virus-free trees
delays the cleanup of U.S. material. This is due to the extra time
and effort it takes to certify and maintain a virus-free program
by the fruit tree industry.

Until the purchaser demands and is willing to pay for trees
certified and indexed as to trueness to name and~Freedom from virus,
he has only the reputation of the seller and nursery to fall back
on.

Problems with stock-scion incompatibilities like the presently
looming brown-line-decline syndrome with some East Mailing types
are suspected to be pathogenic in nature and may be the result of
a combination of viral or mycoplasmal pathogens.

The relationship of stock-scion in regard to known clean
materials is particularly important. It is not good to use virus-
clean materials in one of the components while the virus content
of the other is unknown. One may contain a latent or "hidden"
virus that may damage the other clean component. This was well
pointed out in the decline of Virginia Crab resulting in stem-pit-
ting of the latter hardy stock material. Both parts of a two part
tree must receive a clean bill of health to receive potential bene-
fits of either of the components. In addition, as pointed out by
van Oosten, the use of virus-free bud sources is only one of the
ingredients of a healthy industry. Equally important is the care-
ful attention shown to non-viral aspects of tree selections. Fac-
tors such as fruit finish, trueness to name, stability of the germ-
plasm and a history of the susceptibility of the selection to known
apple virus infections are other important and desirable facts.
Given this information, the grower has a better guarantee of what
the potential of his purchased trees will be in his future orchards.
In today's competitive markets, with increasing production costs,
all factors that can be ascertained should be made available to
the orchardist especially in regard to purchasing his basic ingred-
ient, his trees.

Tests at the Maine Station have demonstrated that considerable
differences in regard to fruit finishing characteristics occur in
selections of Golden Delicious even though they are free from virus
infection. Some virus-free selections produce badly russeted fruit
year after year compared to others which develop good fruit finish
when growing side by side in the same orchard and receiving identi-
cal production practices. (Table 1)

3 -

Table 1,

Non-viral fruit russet in selected clones of Golden
Delicious, in lbs per bushel.

Clone C

Clone H

Russeted

Clean

Russeted

Tree

Heavy

Light

Heavy

Light

Clean

3.5

7.9

3.4*

2.4

4.9

28.5

8.0

21.0

7.6

2.3

17.3

16.5

22.6

11.4

1.9

8.7

27.7

15.5

11.7

1.5

6.2

17.0

12.5

23.7

11.3

2.2

13.9

20.5

13.5

21.6

2.3

7.4

24.8

18.1

14.6

1.0

12.2

23.9

7.2

3.5

.0*

5.9

17.2

9.8

10.7

15.6

10.7

2.6

13.2

20.2

2.4

17.8

18.9

2.7

13.7

13.2

*Less than a bushel

Both clones could be marketed as virus-free Golden Delicious.
It goes without saying that good "seed" produces better crops than
poor "seed." A successful potato farmer insists on knowing the
disease rating and potential of his propagative seed and knows
what the odds are of planting poor seed. It is paradoxical that
apple trees are bought and planted for future envisioned high-
yielding crops often without knowing their possible inherent faults
or capabilities or virus content simply because there is no "pedi-
gree" or labeling system to prevent this from occurring. Somehow
a standard system has to be developed to insure that superior germ
plasm is protected from viral reinfection as well as to insure that
the grower receives specific information certifying that the prod-
uct he receives is the quality product the nursery originally
started with.

Progress has recently been made in reducing certain yellows
diseases of fruit trees originally thought to be viral in nature
but now known to be caused by mycoplasmal pathogens (ultramicro-
scopic bodies contained in phloem cells and transmitted by leaf-
hoppers). There are also similar sized rickettsial and bacterial
type pathogens transmitted by leaf hoppers that affect woody plants.
Fruit trees infected with these pathogens respond to antibiotic in-
jections and disease symptoms are frequently arrested. Such con-
trols are only stop-gap measures as they do not entirely eliminate
infections and must be repeated. With viral infections there are
not even stop-gap chemicals and a tree once infected in the orch-
ard or infected when planted stays infected for the life of the
tree. It is true that the possibility of reinfection with a virus
may occur with insects as in other plants; however, to date, this
has not been shown to happen with the apple virus entities. We,
still do not know what relationship the so-called latent and seem-
ingly inocuous apple viruses have to other plants and should
not continue to spread these around in infected budwood sources.

Tools to handle virus-free superior propagative material are
available. UTiat is needed is an industry-wide cooperative program
establishing checks and controls backed up by regulation and in-
spection measures to insure quality of product from the originator
to the purchaser with proper certification and identification of
tree material. It should be handled by industry so as to keep it
flexible and receptive to changes as they are needed, particularly
with the patented scion and new stock selections, since these must
be controlled by the patent holder. We have the expertise and the
knowhow, all we need is the initiation of a system.

In conclusion, as one old career orchardist was heard to say,
"It takes a lot of Saturday nights without a paycheck before a
newly planted orchard starts to show a profit." The first and most
important aspect of this orcharding business is what you put into
that hole in the ground as the basic investment to live with, grow
with and build upon.

***************

WHEN SHOULD AN EXISTING ORCHARD BE REPLACED

Robert L. Cristensen
Department of Food and Resource Economics

One of the questions confronting an apple producer is that
of the optimal replacement period. Should the old orchard (or
some portion with trees of the same age) be torn out and replaced
now or at some time in the future? This question has become in-
creasingly important because of the trend to compact trees and
higher density plantings.

A difficulty, of course, relates to the fact that a new
planting takes several years to attain production and thus a di-
rect comparison of net income from the old orchard as compared to
the new orchard is not possible. Perrin and Proctor (1Q74) have
outlined a procedure to be used in making such a decision which
takes into account net income flows over the life of the orchard. ^

R.K. Perrin and E.A. Proctor, "The Economics of Replacing Apple
Trees - A Guide for Producer Decision Making", Economics Informa-
tion Report No. 36, Department of Economics, North Carolina State
University at Raleigh, February, 1974.

- 5 -

Th
per yea
the net
value o
ard to
net inc
come £o
ized" n
cipated
orchard

e technique
r over the

present va
btained in
obtain an "
ome from st
r the next
et income f
net income
should be

involves three
life of the new
lue of the orcha
step one is amor
annualized" net
ep two is compar
year from the ex
rom the proposed

for the next ye
replaced.

steps

orcj^a

rd.^

tized

incom

ed wi

istin

new
ar fr

First, annual net returns
rd are discounted to obtain
Second, the net present
over the life of the orch-
e. Third, the "annualized"
th the anticipated net in-
g orchard. If the "annual-
orchard exceeds the anti-
om the old orchard, the old

A simple example may be helpful. The following table presents
the life cycle cash flow for Red Delicious apples sold on the fresh
market.

Table 1

Age of
Orchard

Life Cycle
creases at

Cash Flow Per Acre (With Projected Price In-
2.9 Cents Per Bushel Per Year)

Net Cash
Income

Age of
Orchard

Net Cash
Income

Age of
Orchard

Net Cash
Income

$ -651

$1,277

$1,477

-174

1,360

1,490

-175

1,433

1,469

-62

1,446

1,451

205

1,459

1,432

515

1,462

1,413

847

1,465

1,394

1,033

1,467

1,350

1,113

1,469

1,310

1,194

1,471

1,269

The present value formula with uneven income streams is as
follows:

PV = ^1 + ^2

TT^TT

(1 + i)

(Ui)

where R^^ to R = the atinual net returns in each year
i^ = the appropriate interest rate

Calculating the present value of a future return is the reverse
of compounding interest. If we compound 95 cents at 5-1/4 per-
cent simple interest, we have one dollar at the end of the year.
Therefore, the present value of one dollar received one year from
now, given a 5-1/4 percent interest rate is 95 cents.

"^The following costs are not considered since they are irrelevant
to the replacement decision: all fixed costs for equipment and
buildings and land charges.

- 6

Inserting the numbers from Table 1 into the formula yields the
following (the full series is not presented for reasons of brevity) :

PV =

(-651) + (-174) + (-175) + (-62) +
(I+.IO) ,, . ...2^,. .^.3... ,„.4

(205) + (515)

(1+.10)''(1+.10)"(1+.10)'^(1 + .10)^(1+.10)^

+ _(1,269^

(I+.IO)
= $6,364

For the above table, the present value of the cash flow over
30 years with an assumed rate of 10 percent is $6,364.00.

The annualized value formula is as follows:

A + PV X

1 -

(1 + i)

where :

PV = present value
i = the interest rate

Using the present value computed above and an interest rate of
10 percent, the formula becomes

A = $6,364

= $640

.10

1 -

(I+.IO)

Thus, if the interest rate used is 10 percent the above formu-
la yields an annualized net income of $640.00. If the existing
orchard yields a return net of cash expenses less than this amount,

it should be replaced.

Unfortunately, although this decision criteria. has the appear-
ance of a "rule of thumb" it has many difficulties. Obviously,
the technique requires a large amount of data. Some standardized
yield pattern over time must be assumed and prices
large number of years in the future.

estimated for a
The potential errors in the

Rules of thumb are difficult to attain except in rather simple
decision situations. They almost always assume a number of fac-
tors to remain constant and, as a consequence, often are in error,

- 7 -

future are, however, damped considerably by the discounting techni-
que itself. That is, the effect on the present value of an error
of 50 percent in net income in the 27th year will be relatively
small.

A reasonable manager will also consider the fact that the net
return in a given year from an existing orchard can be highly vari-
able due to the random effects of weather on yield as well as price.
Therefore, the blind application of the $640 criterion might well
be wrong.

In summary: A theoretical decision model does exist for re-
placement of orchards. The orchardist may use the procedure as a
technique to obtain more information concerning such a decision.
This knowledge together with other considerations form the total
bank of information the manager uses in exercising his judgment in
the decision.

***************

CLEANING THE WEED SPRAYER

Cleaning the weed spray between sprayings will preserve the
equipment, help insure uniform spray coverage, and prevent the
chance mixing of incompatible chemicals, or applying traces of the
wrong chemical. Below are suggestions for cleaning weed sprayers
that appeared in Special Circular 81 entitled "Weed Control Sprayers
Calibration and Maintenance" and published by The Penn. State Univ.
Extension Service, University Park, Pennsylvania.

"After each day's use, thoroughly flush with water, both in-
side and out to prevent accumulation of chemicals.

"Choose your cleaning area with great care. It is important
to discharge the cleaning water where it will not contaminate water
supplies, streams, crops, or injure other plants, and where puddles
will not be accessible to children, livestock, pets or wildlife.

"When you change chemicals, or finish spraying for the season,
clean the sprayer thoroughly both inside and out.

"The following steps are suggested for thorough cleaning:

1. Hose down the inside of the tank completely, filling it
half full of water. Then flush out the cleaning water through the
nozzles by operating the sprayer.

2. Repeat the procedure in step 1.

3. Remove nozzle tips and screens. Clean them in kerosene or
detergent solution, using a soft brush. Do not use a knife, wire,
or other hard material to clean nozzle tips. The finely-machined
surfaces of the tips can be easily damaged, causing distortion of
the spray pattern and an increased rate of application.

4. Fill the tank about half full of water and add about 1
pound of detergent for every 50 gallons of water.

5. Operate the pump to circulate the detergent solution through
the sprayer for about 1/2 hour, then flush it out through the boom.

If you have used 2,4-D or an organophosphorous insecticide, be-
fore doing step 6, follow these additional procedures:

a. Replace the screens and nozzle tips.

b. Fill the tank about half full of water and add 1 pint of
ammonia for every 25 gallons of water.

c. Operate the pump to circulate the ammonia solution through
the sprayer for about 5 minutes, and discharge a small
amount through the boom and nozzles.

d. Keep remaining solution in the sprayer overnight.

e. In the morning, flush out all the ammonia solution through
the nozzles by operating the sprayer.

6. Fill the tank about half full of clean water while hosing
down both the inside and outside, then flush out through the boom.

"When finished with the sprayer for the season, remove and store
the nozzle tips, strainers and screens in light oil. Store the
sprayer in a clean, dry shed. If the pump cannot be drained com-
pletely, store where it cannot freeze."

***************

A SUBSTANCE THAT DETERS EGGLAYING BY APPLE MAGGOT FLIES

Ronald J. Prokopy
Department of Entomology

In the preceding 2 issues of Fruit Notes, I have discussed
how apple maggot flies locate food, mates, and egglaying sites and
how this information can be put to practical use in developing traps
for monitoring and (in small orchards) possibly even controlling
maggot fly populations. In this article, I will discuss a unique
sort of behavior engaged in by the apple maggot and its close rela-
tives just after egglaying. The fly-originating chemicals associated
with this behavior offer promise as a new means of controlling the
apple maggot without insecticides in large orchards.

- 9 -

Egglaying by apple maggot females is accomplished when the fe-
male arrives on a susceptible fruit, raises up on its legs, bores
with its ovipositor through the skin of the fruit into the flesh,
and deposits a single egg. The ovipositor is a needle-like protru-
sion from the posterior of the abdomen through which the egg is
passed into the fruit. Following egg deposition, the female with-
draws its ovipositor from the fruit, and then proceeds to circle
around the fruit for about 30 seconds, dragging its fully-extended
ovipositor on the fruit surface behind itself. After this, the fe-
male cleans its ovipositor for a few seconds and then flies off the
fruit.

About 5 years ago, I became very curious as to why the females
engaged in this rather elaborate behavior of ovipositor-dragging.
Actually, my observations of maggot fly oviposition in nature re-
vealed that only about half the cases in which females were seen
attempting to bore into a fruit culminated in ovipositor dragging
while the other half did not. When I examined the fruit, I found
that among females which did drag their ovipositors after attempt-
ing boring, 901 had in fact deposited an egg. On the other hand,
among females which did not drag their ovipositor after attempted
boring, only 2% had deposited an egg. Thus, there was a clear pos-
itive relation between egglaying and dragging the ovipositor after-
ward. This suggested that the act of ovipositor dragging might be
a mechanism for marking the fruit with some sort of substance to
signify the presence of an egg.

I investigated this possibility in a Wisconsin sour cherry
orchard heavily infested by apple maggot flies, which attack sour
cherries in that state. I held a sour cherry by a thin wire at-
tached to the stem, brought the cherry to within a few inches of a
female on a cherry tree, and waited for the female to fly onto the
cherry. Two types of cherries were offered: (1) a clean cherry
never visited or infested by an apple maggot, and (2) a cherry in
which another apple maggot female had just laid an egg and dragged
her ovipositor. It turned out that 621 of the females that landed
on the first type of cherry attempted egglaying, while 01 arriving
on the second type attempted egglaying. Clearly, there was some
sort of deterrent to repeated egglaying associated with the second
type of cherry.

The question now arose as to whether this egglaying deterrent
originated from the eggs, the flies, or the fruit. To answer this
question, I offered the females 4 types of cherries: (1) a cherry
in which a female had laid an egg but was not allowed to drag her
ovipositor afterward, (2) a cherry with a pin prick, and the exuding
fruit juice spread over the fruit surface afterward, (3) a cherry
never visited by any flies, and (4) a cherry in which no egg was
laid, but on which a female (transferred there from another cherry)
had dragged her ovipositor. The results showed that 60-651 of fe-
males that arrived on each of the first 3 types of cherries attemp-
ted egglaying compared with 0% that arrived on the fourth type.

- 10 -

This was strong evidence that some sort of substance (which we will
call a fruit marking pheromone) , secreted from the ovipositor of a
female during ovipositor dragging, was preventing; other females
from attempting to lay an egg.

Of what advantage is it to the flies to deposit such a marking
pheromone? Examination of hundreds of fruits by myself and other
investigators has shown that usually only 1 maggot larva per fruit
can survive to maturity if the fruit is small, 5/8 inch or less in
diameter. Hawthorne fruit, the original native host of the apple
maggot, and sour cherries do not usually exceed this size. There
simply isn't enough food or space in such fruits for more than one
larva to develop. By depositing fruit marking pheromone following
egglaying, a female is in essence saying to other females arriving
afterwards, "Don't bother to lay an egg here. If you do, you'll
be wasting your energy and your egg. There's only room for 1 larva
here, and the larva from my egg already has a head start and would
outcompete the larva from any egg you might lay. You're better off
if you leave this fruit and look for a different one that isn't
marked with pheromone and therefore doesn't already contain an egg."
Apples, which the apple maggot began to infest about 110 years ago,
are of course much bigger than hawthorne fruit or cherries and can
support as many as 15-20 larvae to maturity. Therefore, 15-20 fe-
males can lay eggs in and deposit marking pheromone on apples be-
fore the pheromone begins to become a deterrent to further egglay-
ing.

During the past 4 years, I (alone, or in conjunction with Drs.
Volker Moericke of Bonn, West Germany and Harvey Reissig of Geneva,
New York) have continued to explore various properties of this fruit
marking pheromone. We have found that if pheromone-marked fruit is
kept under dry conditions at normal summer temperatures, the phero-
mone is remarkably stable and is nearly as effective in preventing
egglaying 2 weeks after its deposition as hours after. Surpris-
ingly, the pheromone has proven to be water-soluble, and can be
partially washed away by rainfall. This is not necessarily a dis-
advantage to us, however. For example, we have been able to swish
marked fruit in a container of water, spray the pheromone-water
solution onto clean fruit in laboratory cages, and to a substantial
degree prevent maggot fly egglaying in this fruit. If combined
with an effective spreader-sticking agent, this pheromone should
be able to survive considerable rainfall and remain effective under
a variety of outdoor weather conditions.

Recently, we have found this same sort of pheromone to exist
in all 6 of the close relatives of the apple maggot that we have
examined. These include the blueberry maggot, black cherry fruit
fly, eastern cherry fruit fly, and western cherry fruit fly. Drs.
Byron Katsoyannos and Ernest Boiler of Wadenswill, Switzerland have
also recently found it to occur in the European cherry fruit fly,
the worst pest of cherries in Switzerland. This past year, these
workers collected marking pheromone deposited after about 1 million

- 11 -

cherry fly egg layings in fruit in laboratory cages. They s\\fished.
this fruit in water, and sprayed 10 cherry trees in nature with 2
applications of the pheromone-water solution. The results were ex-
tremely encouraging: only 61 of the pheromone-sprayed cherries had
any cherry maggot eggs or larvae, compared with 100% maggot infesta-
tions of adjacent unsprayed cherries.

In the past 2 months, Reggie Webster and I have discovered that
the fruit marking pheromone of the apple maggot acts net only as
an egglaying deterrent to maggot flies but acts also as a chemical
signal to Opius lectus , a parasite of the maggot eggs. The phero-
mone arrests the parasite females, and elicits a strong degree of
searching behavior for maggot eggs. Parasites encountering fruits
sprayed with marking pheromone are therefore likely to remain in
the area of the pheromone-sprayed tree for a longer time and effec-
tively search out any maggot eggs that might be in the fruit.

The task facing us now is the chemical identification and syn-
thesis of the marking pheromone. This will require the expertise
and equipment of an accomplished pheromone chemist, which are few
in number. We hope in the near future to interest one of them in
tackling this challenging pheromone. If some day the pheromone can
in fact be obtained at reasonable cost, then the pheromone, com-
bined with an effective spreader-sticker, could be sprayed onto our
apple trees to prevent maggot fly egglaying. The deterred females,
which we know move about frequently, might then be captured out by
baited yellow rectangles and/or baited red spheres hung in specific
trap trees. Native or released Opius lectus female parasites would
be retained in the area by the presence of the pheromone. Thereby,
an integrated approach to apple maggot management, combining deter-
rents, attractants, and parasites, could hopefully be achieved.

Establishment and Management of Compact Apple Trees

William J. Lord and Joseph Costante
University of Massachusetts

Part 2

Rootstocks

Commercial interest in size-control rootstocks developed in
the early 1950's in Massachusetts. Presently, those in most
common use are the clonally propagated Mailing (M.) and
Malling-Merton (MM) rootstocks. The degree of dwarfing
induced by these rootstocks is shown in Table 9. A descrip-
tion of these rootstocks and seedlings follows as well as a
summary in Table 10 of the characteristics of the common
and less commonly planted rootstocks.

Table 9. Apple rootstocks presently used in Massachusetts
and their relative degree of dwarfing.

Apple rootstock

Dwarfing (%)
of seedling trees^

M.9
M.26
M.7

MM 106
MM 111
Seedlings

30-50
45-60
55-75
75-90
80-90
100

-Degree of dwarfing will vary with variety and soil type.

M.9. This is a true dwarf rootstock (Table 9) and can be use-
ful for specialized orchard culture by commercial growers.
It is a century old, thus well known. This rootstock has a
brittle root system which means each tree will need to be
supported by a post or by a trellis. It is a very suitable root-
stock for high density plantings. Interest in this rootstock is
increasing for use in "pick-your-own" orchards. On a good
site, with good soil and management, cultivars on M.9 can
be productive.

Virus-tested M.9 rootstocks (free of all known viruses) are
becoming available. Preliminary data from the Netherlands
show that; (a) cultivars on virus-tested M.9 rootstocks grow
more vigorously than those on virus-infected M.9's; (b) virus
tested trees usually produce larger yields than virus-infected
trees; (c) the yield efficiency (poundsof fruit/unit of growth)
of the virus-tested trees is equal to or higher than virus-infect-
ed trees; and (d) fruit quality is also usually better for the
virus-tested trees. The stronger growth of virus-tested trees

could be advantageous on poorer soil but a disadvantage for
high density plantings on strong soils.

Cultivars on M.9 are well suited for trellising or the slender
spindle type of training with a single post parallel to the
trunk for support. Apple varieties differ in vigor on M.9 with
weaker growing types like Idared, Empire, Golden Delicious,
and probably MacSpur easier to train as slender-spindles than
Red Delicious, Mcintosh or Cortland. Slender-spindle trees
will be described elsewhere.

M.26. This is one of the new clones from East Mailing from
a cross of M.I 6 and M.9 and introduced to the U.S.A. about
1 958. Its roots are brittle like the M.9 but trees on this root-
stock have better anchorage. Whether or not trees on M.26
are going to require support is still questionable. At present,
we have found temporary support necessary on windy sites
and when nursery stock quality was poor.

An overgrowth of M.26 forms below the graft union and
burr knots (adventitious roots) form on the stock. It does
not suckei as much as M.7. Trees on M.26 produce earlier
than those of M.7 and it propagates well in stool beds. It is
not resistant to wooly aphids or to collar rot. It is reported
to be very winter hardy. M.26 requires well-drained soil for
optimum performance.

M.26 is gaining popularity in Massachusetts orchards but
many questions about this roostock remain unanswered:
anchorage, soil requirements, whether loss from fireblight
will be a problem, and scion/rootstock effects on growth and
fruiting. Therefore, it is suggested only for trial. We have
observed no serious problems but our experience is limited
to 6 years.

M.26 looks very promising in Michigan. They have lost a
few trees in commercial plantings, but these have been on
low, wet heavy soils. Michigan reports that M.26 will sup-
port a free standing tree. To the contrary, researchers in
western New York are rather "cool" toward M.26 because
of its susceptibility to fireblight and its sensitivity to "wet
feet." It requires a well-drained sandy, loamy soil without
the tendency to drought (Table 8).

M.7 is the best stock we have to give a semi-swarf tree.
Twenty years of commercial experience with M.7 has proven
its reliability under our conditions. Cultivars on this root-
stock come in bearing early and continue to produce good
annual crops. M.7 is not without its faults-it produces suck-
ers from the roots, it tends to lean, particularly when budded
to Red Delicious, and it is susceptible to wooly aphids.

Early

Rootstock

bearir

Seedling

M.13

C-

Robusta 5

MM 104

M.2

M 106

M.7

MM 111

C-

Antonovka

AInarp 2

M.9

A+

M.26

A+

Table 10. Summary of rootstock characteristics
(Letters A-E denote estimate of value: A = excellent; E = poor)

Collar Rot

Tolerance to:

Remarks and

bearing Productivity Anchorage Resistance Wet soil Dryness Low T° Recommendations

Highly vigorous-90 to 100% standard

C-

B-

A-

B+

A+

Medium

vigor range-

'60 to 85% c

)f standard

C-

C+

B-

C-

B +

B+

A+

B+

?
Half -size .

?
and smaller

A+

C-

Use now limited.
Does well on wet soils.
Tolerates heavy soils.

Very susceptible to collarrot.

Never very popular.

Avoid poorly drained soils.

Suckers.

Popular with M.9 interstem.

Inadequately tested in U.S.A.

Inadequately tested in U.SA.

Attractive to mice.

Fire blight susceptibility.

VReported as not being hardy where there are mild periods during winter because it has a very short rest period.

Trees on M.7 need to be budded 8 to 10 inches high in
the nursery so that the trees can be planted deeper in the
orchard. Deeper planting provides better anchorage and
reduces suckering. M.7 produces a tap root, thus trees on
this rootstock should be planted on deep, well-drained soils.
In spite of higher budding, providing temporary basal sup-
port by means of 3-foot long hardwood stakes driven 2 feet
into the ground is advisable for Red Delicious and for all
cultivars on windy sites.

MM 106 has some good characteristics and some believe
these outweigh its weaknesses when budded on semi-
vigorous cultivars (Idared, Empire, or spur-types) and plant-
ed on light loam soils. Trees on this rootstock come into
production early. MM 106 also has a strong well-balanced
root system, therefore, anchorage is not a problem. It is
sucker-free and resistant to wooly aphids.

Our Massachusetts orchards frequently have localized
wet areas and in these areas we lose trees on MM 106.
Furthermore, MM 106 produces large trees with such cul-
tivars as Mcintosh. Loss of trees on MM 106 is commonly
attributed to collar rot but may be more directly related to
winter injury at the crown, soil management, or soil drain-
age. (Trees on MM 106 are slow to mature in the fall and
the trunk tissue near ground level, which is the MM 106
portion of the tree, is late maturing and thus more suscep-
tible to low temperatures in early winter than the other
above-ground portions of the tree.)

MM 111. A good rootstock for sandy loam soils because it is

more drought-tolerant than other size-control rootstocks.
It is more vigorous than MM 106, thus it is of no value to
orchardists desiring to increase tree numbers per acre. Cur-
rently, MM 1 1 1 is being used as the understock for interstem
trees because it produces well anchored trees. It is inter-
mediate in winter hardiness.

Seedling. These formerly constituted the bulk of the root-
stock material used for apple trees. No two seedling root-
stocks are identical in genetic makeup. Trees on seedling
rootstocks are well-anchored and more tolerant to unfavor-
able soil conditions than many M. and MM rootstocks. Trees
on seedling rootstocks are slower to come into production
than those on size-control rootstocks. Seedling rootstocks
will produce trees 25 to 30 feet or more in height without
restrictive pruning. Trees on seedling roots are inefficient
because tree centers are unproductive or produce poor qual-
ity fruit due to inadequate sunlight. Presently, seedlings are
used mainly as the understock for spur-type trees and inter-
stem trees.

Interstem Trees

The interstem tree ordinarily consists of: the understock, the
interstem, and the scion variety (Fig. 2A). Interstem trees
cost more, and they are usually only available by contracting
two years in advance. The scheme most often practiced by
the nurseryman is to bench-graft the interstem (M.9) onto
the chosen rootstock (usually MM 106 or MM 111), plant
this tree in the nursery and bud on to it the scion variety in

August.

Trees consisting of four parts denoted as "C" series inter-
stem dwarf apple trees are available from a nursery in Mis-
souri. These have a seedling root, K-14 winter hardy trunk,
a dwarfing interstem (C-6 or C-52) and the fourth part of
this tree is the desired cultivar (Fig. 2B). The nursery reports
that standard cultivars with C-6 produce trees about half size
of standards on seedling roots. The interstem C-52 produces
trees about two-thirds to three-quarters the size of the cul-
tivar on seedling roots. Combining the spur-type cultivars
with the C-6 and C-52 interstems reportedly produces earlier
bearing, heavier yielding, and smaller trees than if standard
type cultivars are used. Our experience with the "C" series
in Massachusetts is limited.

There is an active interest in interstem trees with M.9
interpiece because of the desire for small trees that do not
require support. Tree size should be intermediate between
that produced by M.9 and M.7 rootstocks. It is suggested
that the M.9 interstem should be at least 6 inches long and
positioned on the stem of the understock at least 12 inches
from the top of the roots to permit deeper planting.

Interstem trees are suggested for trial.

Orchard Design

Tree density defined. Terminology and planting distances
used vary among researchers with compact apple trees. Below
is shown the names we have chosen for this publication, the
tree number in each density, and the rootstock and interstem
combinations that can be utilized in each density.

Rootstock and interstem
combinations that can be
Density Number of trees/A utilized in each density^

Low Less than 1 14

Medium 115 to 249

High 250 or more

Seedling, MM 111, MM 106,
Alnarp2, M.13, C-52/K-14/
seedling, M.7.

MM 106, M.7,C-52/K-14/
seedling, C-6/K-14/seedling,
M.9/seedling, M.9/Alnarp 2,
M.9/MM 111,M.9/MM 106,
M.26.

M.9

Cultivar vigor and soil type are factors influencing tree
spacing.

Tree spacing. We cannot make firm recommendations on
planting distances because our experience is too limited.
Furthermore, the number of variables affecting tree size
are great— orchard site, soil, severity of pruning, nutrition
and tree training among others. However, as a guide we have
suggested in Table 11, planting distances that seem reason-
able minimum spacings for our conditions in Massachusetts.
Similar tree spacings are given for both medium and low
vigor cultivars which reflects our lack of experience with the
spacing requirements of various cultivar-rootstock combina-

Fig. 2. Interstem trees. (A) is a3-piece tree with an MM 106
understock, M.9 interstem, and Mcintosh as the
cultivar. (B) is a 4-piece tree with a seedling under-
stock, K-14 winter-hardy trunk, C-6 dwarfing inter-
stem, and Mcintosh as the cultivar.

tions. However, we have 20 years of commercial experience
with M.7 and strongly believe that without restrictive prun-
ing, 16 ft. X 24 ft. should be considered the minimum spacing
of a permanent planting of vigorous cultivars on this root-
stock and that on some soils 20 ft. x 30 ft. spacing is not
too wide.

We have allotted an 8 ft. alley for orchard travel and har-
vest operations. If you like a 7 ft. alley, decrease the spacings
between the rows by I ft. (for example, a 16 ft. x 24 ft. spac-
ing to 16 ft. x 23 ft.).

It cannot be overemphasized that as planting density
increases, it becomes even more important that soil, cultivar
and rootstock be correctly matched. When deciding on what
density to plant, consider the following factors: (1) the
characteristics of the site and soil— windy, poorly drained
soil, etc.; (2) cultivar being planted— vigorous, spur-type, etc.;
(3) time available for tree training and pruning; and (4) meth-
od of marketing— "pick-yourown," processing, or fresh use.

Low density tree planting. Usually allows for full tree devel-
opment with a minimum of pruning to restrict tree spread.
It requires the least investment per acre while production
costs are below those of orchards on seedling rootstock.
Massachusetts growers should consider low density plant-
ings when the cultivar is a vigorous-growing (Mcintosh and
Delicious) standard-type tree and the rootstock is M.7 or
MM 106 because it is difficult to restrict the size of these
trees. Plantings of these cultivars on these rootstocks spaced
10x18 feet, 15 x 20 feet, or 20 x 20 feet have become so
dense that growers have been forced to remove trees while
the orchards were still relatively young.

Medium density tree planting. Thisdensity will require more
careful attention to training and pruning trees than with low
density planting to prevent tree crowding and maintain fruit
quality. It is essential to maintain conical-shaped trees

(Christmas tree shape). The higher investment per acre in
comparisonto low density plantings (Table 1) should be off-
set by earlier, higher yields. Medium density plantings involve
free standing trees-MM 106, M.7, M.26, and interstem trees.
However, more experience is needed before we can be sure
of the stability of trees on M.26 without support.

The trees are smaller than in the low density planting,
easier and less cos'tly to spray, and a higher percentage of
the leaf area is exposed to sunlight which is essential for
flower bud formation and high fruit quality.

High density tree planting. This type of planting will require
the use of M.9 rootstock with the tree individually staked
or supported by a trellis. Thus cost of establishment is
extremely high (Table 1). Adjustments in orchard size and/or
management procedures will be necessary if sizeable acreage
of high densities is planted by the established grower because
of the careful attention needed in growing the trees and
containing them within their allotted space. Few soils in
Massachusetts are suitable for trees on M.9 without providing
supplemental water.

In the Netherlands, where all modern plantings are on
M.9, there is a rule of thumb that states that orchard size
should be governed by the number of skilled pruners on the
farm. An apple orchard of 20 to 25 acres is considered large
in the Netherlands and the grower sells his fruit through an
auction, jumble-packed in wooden crates. To the contrary,
the average Massachusetts grower has 50 or more acres, grades
and packs his fruit into bags, cell count cartons or trays,
and in many instances retails part of the crop. Time is such
a limiting factor that many orchardists are forced to hire

custom pruners to prune their bearing orchards.

Orientation of tree rows. North-south orientation of tree
rows is preferred because it favors maximum exposure of
the leaves and fruit to sunlight. However, frequently the
topography of the land and orchard boundaries dictate the
directions in which the tree rows will extend.

When designing the orchard, allow for service roads and
sufficient space at the ends of rows for equipment maneuver-
ability.

Pollination. Most apple cultivars are self-unfruitful and
require cross-pollination to set a commercial crop. In select-
ing a cross-pollinating cultivar, the following factors should
be considered: (1) Age when it begins to flower, (2) season
of bloom, (3) viability of pollen produced, (4) tendency to
flower annually, (5) cross-incompatibilities, and (6) adapta-
bility and value of the cultivar to the region.

Table 1 2 lists some of the cultivars grown in Massachusetts
according to their season of bloom. These are generally suit-
able cross-pollinizers for each other; several exceptions are
noted. These cultivars do not always bloom in the same rela-
tion one to another each year. During years when the pre-
bloom temperatures are high, all cultivars are apt to bloom
at about the same time; when the pre-bloom temperatures
are low, the bloom is late and 7 or more days may elapse
between the early- and late-blooming cultivars. Bloom peri-
ods of those cultivars listed in the early- and mid-season
groups should overlap sufficiently for suitable cross-pollina-
tion in most seasons; the same would be true for those cul-
tivars in the mid-season and late categories. It would be

Table 11. Suggested minimum planting distances for various apple cultivar/rootstock combinations.^

Rootstock or interstem combination

Tree spacing (ft) and trees/acre (in parentheses) for:

Vigorous Medium vigor and

cultivarsV low-vigor cultivars^

M.9 or M.9A

M.26

M.9/MM 106

M.9/MM 111

M.9/Alnarp2

M.9/seedling

C-6/K-14/seedling

C-52/K-14/seedling

M.7or M.7A

MM 106

MM 111

8x 16
14x22
12 X 20
14x22
15x 23
15x23
15 x 23
16x24
16x24
18x26
20x28

(340)
(141)
(181)
(141)
(126)
(126)
(126)
(113)
(113)
( 93)
( 77)

14 (518)

12x

20(181)

lOx

18(242)

12x

20(181)

13x

21 (159)

13x

21 (159)

13x

21 (159)

14x

22(141)

14 x

22 (141)

16x

24(113)

18x

26 ( 93)

^Increase spacings by 2 feet on heavy soils.

VMclntosh, Delicious, Cortland, Macoun, Puritan, Spartan.

'^Most spur-type Mcintosh, spur-type Delicious, Paulared, Tydeman's Early, and Jerseymac have medium vigor. Golden Delicious,
Idared, Empire, MacSpur, and Rome are cultivars with low vigor.

Table 12. Approximate bloom period of apple cultivars
producing viable pollen for cross-pollination.^

Early

lidseason

Late

Empire

Jerseymac

Julyred

Lodi

Mcintosh

Niagara

Paulared

Puritan

Tydeman

CortlandV Macoun

Delicious'* IVIelrose''

Early Mclntoshy Northern Spy, Red Spy

Golden Delicious Rome, Gallia

I da red

Spartan

Spencer

^ Bud sports or strains of an apple cultivar are not cross
fruitful with each other or the parent cultivar even though
they have viable pollen and functional ovules. Examples:
Delicious strains such as Richared, Starking, Red Prince
and Starkrimson will not pollinate Delicious or each other
and vice versa.

VCortland and Early Mcintosh are cross-incompatible but
are suitable pollinizers for other cultivars.

'^Melrose and Delicious are said to be cross-incompatible.
Both are suitable pollinizers for other cultivars.

The cultivars listed below are triploids; they do not pro-
duce viable pollen and are ineffective in cross-pollination.

Early

Midseason

Late

Gravenstein

Baldwin

Mutsu

Rhode Island Greening

Spigold

unwise to rely on early blooming cultivars to cross-pollinate
a late-blooming cultivar or vice-versa.

One should not rely entirely on strongly biennial culti-
vars such as Early Mcintosh as cross-poliinizers for annual
cultivars such as Cortland, Delicious and Mcintosh. When a
strongly biennial cultivar fails to bloom, there is no suitable
pollen to cross-pollinate the usual annual flowering cultivar.
Hence, the annual cultivar will fail to set a commercial crop
in alternate years and tends to become biennial, also.

In low density plantings, the pollinating cultivar may be
set either in solid rows or interplanted with the main cultivar.
The former is preferred because interplanting with the main
cultivar can create problems in spraying and be an incon-
venience in harvesting. When the pollinator cultivar is set in
solid rows, alternate 1 or 2 rows of the pollinator with 4 rows
of the main cultivar. Where interplanting is used, every third
tree in every third row should be a pollinator cultivar.

Early Mcintosh and Golden Delicious are probably par-
tially self-fruitful and it is advisable to set them in solid rows
with fewer pollinating rows than with other varieties to
reduce the tendency of oversetting and for convenience of

spraying. To the contrary, Cortland, Mcintosh and particu-
larly Delicious require a high proportion of pollinators, par-
ticularly on sites where poor pollinating weather is apt to
occur rather frequently.

It is well documented that foraging bees tend to work up
and down rows rather than across rows. When trees are
planted at low densities and the trees are not crowded in
the row, the bees will move between trees somewhat indepen-
dently of the row. However, medium and high density plant-
ings may eventually have little space between trees in the
row, thus forming virtually a solid hedgerow. As a result,
the distribution of pollenizer pollen across one or more rows
may be seriously limited because of movement of the bees
along the hedgerows instead of between adjacent rows.
Thus, it may be advisable that every fourth tree in every
row be a pollinator cultivar.

Orchardists almost invariably rely on honey bees for pol-
len dispersal, and they usually do this by renting colonies
from beekeepers. We suggest that one, but preferably two
colonies per acre be brought into the orchard at the time of
10% bloom. The hives may be arranged singly or in groups
of 4 in various locations. Grouping is superior because
colonies competing with each other increase bee activity.
Bees can "set a crop" in 2 good flying days (temperature
about 65° F and partial sun). After full bloom, bees should
be removed as soon as possible so that you can continue
your spray program.

Soil Preparation

Frequently, hay fields and pastures with reasonably good
fertility, can be planted to trees without extensive land
preparation. While it is generally true that newly-set fruit
trees do very poorly in a heavy grass sod, it is possible to
obtain growth equal to that obtained under cultivation by
the use of herbicides.

Hay fields, and especially pastures, frequently have low
fertility. Fertility can be increased by applying 500 to 600
pounds of a complete fertilizer such as 10-10-10 and by
application of sufficient high magnesium lime or a high cal-
cium lime. A soil pH of 6.0 to 6.5 is desired for orchards.
Soils which have not had frequent applications of lime will
require 2 or more tons of lime per acre. (It is always advis-
able to have the soil tested to determine its pH and lime
requirements. Information on taking soil samples and where
to send them for analysis can be obtained from your County
Extension Office.)

Paraquat (an herbicide) can be applied in 4 to 6 foot wide
strips along the tree rows the year prior to planting or after
planting to control grasses and broadleaf weeds. Residual
herbicides should not be used for preplanting weed control
because the trees planted in the treated soil may be killed.
When paraquat is used the year of planting, the spray must
not hit the v\/ood of the tree, otherwise injury may occur.
Information on herbicide usage can be obtained from your
County Extension Service.

On newly cleared land and soils which are low in fertility

and are not too stony or likely to erode badly, It is advisable
to build up the soil by seeding and plowing or disking under
cover crops before planting trees. Spring oats, buckwheat,
or millet can be sown as the summer cover crop and spring
oats for the winter cover crop. This is an opportune time to
apply lime because it can be incorporated into the soil during
the disking of the cover crops.

When the trees are planted, a mixture of grass seed and
oats can be sown. During the summer, the oats can be cut
and let lie or be raked around the trees for mulch.

On a fairly level site which is not subjected to serious
erosion, it may be possible to interplant with low growing
crops such as pumpkins, for "pick-your-own" or roadside
stand sales. These crops can be grown for a few years to
help defray the cost of caring for the young trees until they
come into production. The rows of the cultivated crops
should not be planted so close to the tree rows that they
interfere with growth of the young trees. Intercrops in a
young orchard should be considered as a temporary enter-
prise and they should be discontinued just as soon as they
interfere with tree growth and care.

Mapping the Orchard

Once the decisions are made concerning cultivars, rootstocks,
and planting distances, the orchard design should be drawn
to scale on paper. Be sure to map the location of the drainage

system, wet spots, and changes in soil type.

After planting, record any changes in original planting
plan, and record the date of planting, name and address of
nursery supplying the trees, weather conditions at time of
planting, and other information of value.

Staking the Field

A base line (the first row) is laid out on one side of the field
parallel with an adjacent row of trees in an existing orchard,
a fence, or a road. Stakes are placed along this line where
the trees are to be planted. {I/Vhen staking the field be sure
to allow sufficient room along the edges of the orchard for
equipment maneuverability.) Now establish several rows of
stakes at the spacing desired for the alley between trees at
right angles to this row (Fig. 3). Right angles can be deter-
mined with a measuring tape and stakes using the carpenter's
square method in which 9 ft. X 12 ft. x 15 ft. or 12 ft. x 16 ft.
X 20 ft. are the lengths of the sides of the right-angled triangle.
A right triangle can be constructed out of wood strips if
desired. Now that the stakes are in place, the remainder of
the orchard can be staked by "sighting-in" on the stakes
and with the tape measure.

When staking the field only 1 or 2 months prior to plant-
ing, a couple of handfuls of lime can serve as an alternative
to staking each tree location.

Fig. 3. A method of staking the orchard before planting. In this planting, the first row is laid out 30 feet from an existing
fence and the location of the trees in the row staked (12 feet apart in the row). Right angles are determined at both
ends and the middle of the first row with a 12 ft. x 16 ft. x 20 ft. right triangle. By stretching a measuring tape along
the 16 ft. side of the right triangle, the location of the trees can be staked. The rows are 20 feet apart.

Cooperative Extension Service
University of Massachusetts
Amherst, IVIassachusetts
R. S. Whaley
Director
Cooperative Agricultural Extension Work
Acts of May 8 and June 30, 1914

Official Business

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FRUIT
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 42 (No. 2)
MARCH/ APRIL 1977

TABLE OF CONTENTS

The Use of a Pressure Tester to Measure Firmness of Apples
Apple Trees on M.26

Mite Predator Studies in Massachusetts Apple Orchards in 1976
Pomological Paragraphs

Selecting the best spacing for the variety, rootstock and
soil

Early heavy cropping

THE USE OF A PRESSURE TESTER TO MEASURE
FIRMNESS OF APPLES

William J. Bramlage
Department of Plant and Soil Sciences

Firmness of apples is used worldv\fide as a measure of ripeness
and "condition" of the fruit. The most widely used instrument for
firmness measurement is the Magness-Taylor pressure-tester (devised
in 1925), although the Effegi tester (developed recently in Italy)
has met some acceptance due to its compact size and convenience.
Tests comparing the Magness-Taylor with the Effegi indicate that
readings of the 2 instruments are quite comparable, and I shall as-
sume that what is said in this article about use of a Magness-Taylor
is equally true about use of an Effegi tester.

With its worldwide and longstanding use, and the importance
of its measurements, one may assume that the Magness-Taylor is used
in a standard way and that readings by different users are closely
comparable. Not so! There is no standard technique and readings
are often grossly variable among users of the instrument. In 1
test in Geneva, New York, it was found that professional users of
a Magness-Taylor varied as much as 3 to 4 lbs in the readings they
obtained on the same lots of apples! Following an informal discus-
sion at a meeting in December, 1975, where it was evident that use
of pressure testers differed widely, 10 Northeastern post-harvest
horticulturists-^ agreed to 'gather data on factors that can influ-
ence pressure test determinations, in hopes of standardizing a tech-
nique. The results of this collaborative effort, coordinated by
Dr. G.D. Blanpied of Cornell University, are summarized here.

The Magness-Taylor pressure tester : The instrument itself may
be a cause of erroneous readings. First , there are 2 sizes of plun-
ger "heads" that might be used. For apples, the larger one, with a
diameter of 7/16 inch, is always used; the smaller, 5/16 inch head
is for use on pears, which are much harder than apples until nearly
ripe. A second problem is that the instrument may not be calibrated.
Calibration is relatively simple and should be checked regularly.
To calibrate, place the plunger on an accurate scale and press down
slowly until the scale registers a weight that occurs on the pres-
sure tester scale. Check this weight against the recorded reading
on the pressure tester. Several different points on the scale should
be tested in this manner. If the readings on the scale and on the
tester do not correspond, the readings on apples you obtain with
the tester should be adjusted accordingly, or better, the spring in
the pressure tester should be replaced or the instrument sent to the
factory for re-calibration, if necessary. A rusty spring should
always be replaced.

Collaborators were: G.D. Blanpied, Cornell Univ.; D.H. Dewey, Mich. State Univ.;
R.E. Hardenburg and A.Watada, USDA, Beltsville, Md. ; M. Ingle, W.Va. Univ.;
R. LaBelle d, L. Massey, Geneva, N.Y. ; G. Mattus, V.P.I and S.U., Blacksburg,Va. ;
W. Stiles, Univ. of Me. and W.J. Bramlage.

- 2 -

Choosing a sample for testing : The user should consciously and care-
fully choose the fruits that will be tested, knowing the factors that
may influence the readings.

A. If you are testing in the orchard, it is likely that fruit
from the outside of the tree will test firmer than those
toward the inside of the tree.

B. Fruit size is a very important factor. In general, the
larger the fruit, the softer it will be. Sometimes a 1/4
inch difference in diameter can make a 1 or 2 lb differ-
ence in the pressure test! Following years of careful
record-keeping. Dr. George Mattus suggests that you not
vary more than 1/4 inch in diameter among the fruit you J
test. Obviously, some kind of sizing device is therefore '
necessary in choosing a sample. Further, you should test

a size that is representative of the majority of the crop,
and specify the size you are testing. You cannot accurately
compare firmness of lots of fruit if you sample 3-inch fruit
in one lot and 2-1/4 inch fruit in the other.

C. The temperature of the fruit can have a small but sometimes
significant influence on pressure tests. Firmness tends

to be slightly less when apples are warm than when they
are cold. This is not nearly as important a point as is
the size of the fruit, but for maximum accuracy, the user
should be consistent about testing either warm fruits or
cold fruits.

D. A very important but controversial question is: How many
fruits should you test, and how many times should you test
each fruit? Obviously, 1 fruit is not sufficient, and the
more fruits you test, the more accurate will be the aver-
age pressure reading. But, between these 2 indisputable
points there is little agreement. Many people test only
once per fruit, but many others test twice -- once on each
of the opposite sides (usually blush and green sides).
Some people may even test as many as 4 points on an apple.
(Is 1 apple tested on 2 opposite sides equal to 2 apples
tested on 1 side? Probably not.) How many different fruits
should you test? Most people agree that 10 fruits from a
given lot is probably minimal for accuracy, but may prefer
20 to 25 fruits to reduce error. If only 10 are tested,
they should probably each be tested on 2 opposite sides.

I personally prefer testing 20 apples once on a designated
(green or blush) side. The significant point here is, how-
ever, that a large enough sample must be tested to overcome
the variation within the population of fruits being samp-
led. If large variation exists, a large sample size is
required.

Making the test : Having calibrated the pressure tester and care -
fully chosen a~sample, how should you test the fruits? First, you
shouldrecognize that the fruit is not of uniform firmness. Gener-
ally, the blush side is firmer than the green side. This differ-
ence may be as much as 1 lb of pressure. Therefore, either consis-
tently test the blush side, knowing it is firmer, or the green side,
knowing it is softer, or else test both the blush and the green sides
and average the readings.

Since the skin badly distorts a pressure test on an apple, it
must be removed from the area to be tested. The depth of the cut
removing this skin influences the reading: the deeper the cut, the
higher the reading. Dr. Robert Hardenburg suggests use of a potato
peeler (stainless steel to avoid rusting) for quick, shallow, con-
sistent cuts. These cuts should be made at a point half way between
the stem and calyx ends of the fruit. Never test a bruised area.

For testing, the fruit should be placed on a hard surface (e.g.,
table top) rather than being hand-held. The plunger should be in-
serted to the line inscribed on the plunger . Testing only to the
"yield point" of the fruit tissue (i.e. , when it "gives") produces
an erroneously low reading, and going beyond the line gives a high
reading. However, the most critical feature of testing is the speed
of applying the force . The faster you apply the pressure, the higher
will be the reading. The proper speed is about 2 seconds, and to
regulate your speed it is suggested that you say to yourself, "1001,
1002, as you insert the plunger into the fruit. This may sound
childish, but it is extremely critical as can be seen simply by ap-
plying force at different speeds during calibration. The user needs
to frequently check himself during testing to make sure he is test-
ing at the proper speed. Applying pressure too fast is probably the
greatest source of false readings by users of the pressure tester .

Having tested the fruit, how do you read the scale? Some read
it to the nearest whole lb., others to the nearest 1/2 lb., and some
may even read to the nearest 1/10 lb. It seems clear that reading
to the nearest 1/2 lb. is sufficient, and if your sample size is
reasonably large, the nearest 1 lb. is satisfactory. Again m.y prefer-
ence is to the nearest 1/2 lb.

With an accurate instrument, careful sampling, and precise
testing, you should obtain a quite accurate firmness measurement
of the fruits. But this accurate measurement still may not truly
represent the "condition" of the apple. Some sources of error are
the following.

A. Nitrogen (N) level of the fruit: Increasing the N level in
apples may reduce firmness of apples more than it affects
postharvest "condition" of them if the apples were at the
threshold of N-deficiency before treatment. Thus, you may
misjudge "condition" by comparing lots of widely varying
N levels.

B. Watercore: The more watercore in a fruit, the firmer it
may pressure test, even though increasing watercore indi-
cates increasing fruit maturity. Pressure tests may indi-
cate very little about "condition" of watercored apples.

C. Water loss: If apples are losing water rapidly, they may
"soften" due to loss of turgor, i.e., wilting. This soften-
does not represent what is usually regarded as "loss of con-
dition."

There are probably other complicating factors, also, but these
examples illustrate the importance of observing the fruit you are
testing, recognizing symptoms of complicating conditions, and being
careful about how you interpret the results of pressure tests.

With the importance of firmness in the acceptability of apples,
and the ease of using pressure testers, these instruments seem cer-
tain to remain as key determinants of apple quality in the foresee-
able future. Yet, it is shocking to see how erratically these de-
vices are used. At present, a term, like "10-lb Mcintosh" may actu-
ally mean little to anyone but the person who tested the fruit; these
same apples may test 12 lbs. to another person, and 8 lbs to still
a third person. Yet, Mcintosh apples truly testing 12 lbs. of pres-
sure have grossly different potential than ones truly testing 8 lbs.
If we are going to use firmness as a meaningful guide to apple qual-
ity, we all need to re-examine our testing procedures, and do our
utmost to standardize them so that our determinations can become
more comparable and our interpretation can be more accurate. Here
is a problem that can be overcome with good judgement and little or
no expense.

***************

APPLE TREES ON M.26

William J. Lord
Department of Plant and Soil Sciences

Observations this past year show that the vigor of non-bear-
ing trees on M.26 is variable. ( Assuming that all the trees are
on M.26.) Trees of the same variety , within a block, may be ex-
tremely variable in some orchards with some weak and/or difficult
to train. This may mean that trees of M.26 react more to unfavor-
able growing conditions than those on more vigorous size-control
rootstocks .

Roger Young, Kearneysville, West Virginia, reported at the
19th Conference of the International Dwarf Fruit Tree Association
on March, 1976, that leaning in a test orchard of the trunk or leader
(central leader not being upright) of trees on M.26 was a problem

5 -

especially with 'Stayman', ' Rome ' , ' Winesap ' , and 'Jonathan' culti-
vars. Non-bearing 'Red Prince Delicious' planted at our Research
Center in 1971 or 1972 have developed leaning. The leaning appears
to be caused by something other than poor anchorage . In other orch-
ards, poor anchorage appears to be a problem. Trees that were pro-
vided either no support or a short stake for support at planting,
now require an 8-foot stake for support in some instances. This
was not due to early, heavy cropping. Whether or not the stakes can
be temporary or needed permanently is not known.

We need a free-standing tree smaller than that produced by M.7.
But I'm beginning to wonder if M.26 is the answer for some orchards.
Approximately 8% of the trees in Massachusetts on size-control root-
stocks are on M.26. Thus, in several years we can better evaluate

M.26.

***************

MITE PREDATOR STUDIES IN
MASSACHUSETTS APPLE ORCHARDS IN 1976

Robert G. Hislop and Ronald J. Prokopy
Department of Entomology

In several 1976 issues of Fruit Notes , we described certain
techniques developed by researchers in other apple growing regions
of North America to reduce spraying for apple insects and mites
without sacrificing fruit quality or quantity. These accomplish-
ments were made possible by careful monitoring of insect popula-
tions in the orchard, and selection of orchard sprays to which mite
predators were resistant. In this issue of Fruit Notes , we will
describe work we have been doing this past year toward a similar
goal of reduced spraying for mites in Massachusetts apple orchards.

Our study is long term and its objectives twofold: (1) to
determine which species of mite predators occur naturally on wild
or unsprayed abandoned apple trees, and (2) to determine if any of
these predators occur or thrive in commercial orchards. This should
provide some indication as to which types of spray programs are con-
ducive to the buildup of these beneficial predators in our orchards.

We knew at the beginning of our study that Amblyseius fallacis ,
a predatory mite known to play a key role in the suppression of red
and two spotted spider mites in some commercial apple orchards in
the midwest and southeast, also occurs in some northeastern states.
Several of its habits are well known, such as remaining in the
ground cover until July, when it moves up into the tree canopy to
feed on plant feeding mites. Here it is exposed to the constant
onslaught of cover sprays directed against principal insect pests.

- 6 -

Because of this exposure, A. fallacis eventually developed resis-
tance to certain organophosphorous Tiisecticides . Portions of our
orchard survey, described below, were undertaken in hopes of dis-
covering this particular predator in Massachusetts orchards.

Last spring, we began intensive tri-weekly sampling of mite pop-
ulations from March through October in the orchard at the Belcher-
town Research Center, and in 6 commercial and 3 abandoned orchards
in 3 different locations across the state. In the Belchertown orch-
ard, each of the materials Zolone*, Guthion*, Imidan*, and Sevin*
were regularly applied by airblast sprayer to each of 3 groups of
trees, with 3 groups left unsprayed for comparison. Among the com-
mercial orchards, 3 used one type of spray program, while the other
3 used a different program. In each orchard, samples were taken of
the ground cover under the trees, bark, and leaves of 3 'Red Delici-
ous' and 3 'Mcintosh' trees. The ground cover and bark were sam-
pled to determine if mite predators, especially A. fallacis , existed
in these habitats at different times of the season.

Bark and ground cover samples were placed in funnels under
heat lamps which forced mites out of the samples into jars of pre-
servative placed at the bottom. Leaf samples were brushed in a
mite brushing machine, the mites landing on glass discs on which
they could be readily observed. All mites were counted, including
red and two-spotted spider mites, tiny apple rust mites, and preda-
tory mites and insects.

We also sampled the leaves of 20 other commercial orchards
from which we had obtained the spray history. This sampling was
conducted only once--at the peak of the mite season in August.

Our results to date reveal arboreal mite predators to be widely
distributed in Massachusetts apple orchards. However, Stethorus
punctum , the black lady beetle important in Pennsylvania apple orch-
ards , and Typhlodromus pyri , the predatory mite important in Western
New York, were not found in our survey. The situation in abandoned
orchards was quite different from commercial ones. In commercial
orchards, fewer kinds of mite predators were found, the predominant
species being A. fallacis . This predator was seldom encountered in
abandoned orchards'!! Red and two-spotted mites were virtually ab-
sent in abandoned orchards, which is not surprising in view of the
high predator populations found there. Growth of these populations
was likely aided by high abundance of one of their food sources,
the apple rust mite.

In many commercial orchards where the spray program included
repeated applications of Zolone* and/or Benlate*-glyodin combination
arboreal mite predators were scarce or totally absent. It appears
that one or all 3 of these materials may have been toxic or repel-
lent to the predators. In such orchards, the two-spotted spider miti

*Trade name

was the principal mite pest and miticides were applied repeatedly
(2-4 applications) for its control. Two-spotted populations first
appeared in early June, increasing thereafter until miticides were
applied in July and August.

In comr.ercial orchards where the above materials were not used,
arboreal mite predators, particularly A. fallacis , were present in
numbers sufficient to exert some suppressive effect on the spider
mites. In most such orchards, the predominant mite pest was the
European red mite. In 2 of the intensively studied orchards, pop-
ulations of red mite peaked in late June in one orchard and late
July in the other. In each case, only one miticide application
was needed. A. fallacis (which appears to be only slightly suscep-
tible to the principal miticides used in all sample orchards: Plic-
tran* and Omite*) first appeared in the trees in July and increased
thereafter in apparent response to increasing European red mite pop-
ulations. The miticides undoubtedly eliminated part of A. fallacis '
food source but apple rust mites were present in sufficient numbers
to provide alternate food. In the third orchard studied intensively,
spider mites never reached numbers high enough to cause damage and
no miticide was needed.

None of the arboreal mite predators, including A. fallacis ,
appeared in the bark samples, suggesting wind dispersal as the pri-
mary means of their getting into the tree. The ground cover samples
are still being analyzed. When completed, this analysis should
tell us more about the early season habits of these mite predators.

We are encouraged by the wide distribution of certain arboreal
mite predators such as A. fallacis in Massachusetts apple orchards.
However, results to date tend to confirm our suspicion that these
important predators either cannot survive or are repelled in orch-
ards sprayed with certain insecticides and/or fungicides. This is
of immediate economic importance to the grower, and may have serious
long-term consequences as well. For example, if spider mites ever
become resistant to all available miticides (which is a possibility),
orchardists using these materials will almost certainly have little
protection against spider mite buildup. In orchards where the build-
up of mite predators is not discouraged, it is likely that miticide
usage can be reduced in most cases.

During the next two years, we will be continuing our field and
laboratory studies so that we may more fully comprehend the poten-
tail of natural enemies, particularly mite predators, in the suppres-
sion of red and two-spotted spider mites in our commercial orchards.

***************

POMOLOGICAL PARAGRAPHS

S electinR the best spacing for the variety, rootstock and soil .
We can try, but I believe that one cannot accurately select the
best spacing for the variety, rootstock, and soil under our condi-
tions. To do this, one may have to use several rootstocks in the
same row because of the variable nature of our soils. Even then,
it would be guess work. Personally, if I make an error, I prefer
that the spacing be too wide rather than too close. I believethat
the average Massachusetts apple grower who stores and grades his
own fruit hasn't the time nor money to fight trees too closely
spaced for their natural vigor.

ft**************

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

***************

All pesticides listed in this publication are registered and cleared
for suggested uses according to Federal registrations and State Laws
and regulations in effect on the date of this publication.

When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.

NOTICE: THE USER OF THIS INF0R>1ATI0N ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

WARNING: PESTICIDES ARE POISONOUS. READ AND FOLLOW ALL DIRECTIONS
AND SAFETY PRECAUTIONS ON LABELS. HANDLE CAREFULLY AND STORE IN
ORIGINAL LABELED CONTAINERS OUT OF REACH OF CHILDREN, PETS AND LIVE-
STOCK. DISPOSE OF EMPTY CONTAINERS RIGHT AWAY, IN A SAFE MANNER
AND PLACE. DO NOT CONTAMINATE FORAGE, STREAMS AND PONDS.

Establishment and Management of Compact Apple Trees

William J. Lord and Joseph Costante
University of Massachusetts

Parts

Purchasing Trees

Quality trees are the foundation of a successful orchard;
anything less is a gannble. Thus, the following points are
worthy of nnention.

1. Plan ahead (a year or two is best), thereby making
it possible to plant the trees you want when you
want them.

2. Tree quality rather than price should be the major
consideration. One-year-old trees, 4 to 6 feet in
height and at least 5/8 inches in diameter usually
grow faster than lower grades.

3. Insist on 1-year-old branched trees or whips budded
14 to 16 inches above the bottom of the rootstock.
Trees budded lower than this may have to be staked.

4. We suggest purchasing from nurseries that dig their
trees in the fall and store them.

5. Don't accept second best even if it means waiting a
year or more for quality trees on the desired root-
stocks and/or of the desired cultivar. The time waiting
usually can be well spent on site preparation.

6. When ordering interstem trees be sure to specify a 6
to 7 inch dwarfing stem piece grafted on a 7 to 10
inch long understock. Degree of dwarfing varies with
interstem length— the longer the interstem, the great-
er the dwarfing.

Care of Trees on Arrival From the Nursery

Check the trees to determine if tree count and cultivar/root-
stock and size agrees with order and to determine if injury
to the trees might have occurred in handling and shipping.
Do this where it is cool and the roots will not dry out.

If planting conditions are not suitable, open the bundles
of trees and store them in a cool, well-ventiled area and be
sure the roots are kept moist, or heal them in a shady area,
or cover the roots with wet soil, peat or sawdust in an open
shed. DO NOT store trees with apples or where they have
been stored. It is possible that residual ethylene in the stor-
age atmosphere might break dormancy of the trees and when
planted they may fail to grow properly or even die. Pear trees
are especially sensitive to injury.

All photographs in this and subsequent parts bv Louis J. Musante.

Time of Planting

Fall planting of apple trees is not recommended for Massa-
chusetts because there is too much risk of winter injury to
the trees. The trees should be planted in the spring as soon
as the frost is out of the ground and the soil easily worked.
Most years, planting can commence in late April, thus the
target for receiving trees from the nursery should be April 1 5.
Late planting is a frequent cause of unsatisfactory tree
growth.

Planting

The soil should be in a good workable condition at planting.
Do not plant in a wet "soggy" soil. The hole for the tree
should be large enough to take in the entire root system. It
is important to dig the holes the right depth because if dug
too deep the tree may settle after planting and the graft
union will be below ground. To the contrary, the hole should
be deep and wide enough so that the roots will rest on the
bottom without having to "pin-them-down" with soil.
Plant the trees in good loam soil. When the hole is hand-dug,
place the top soil on one side and the subsoil on the other
side. This will enable you to place the top soil around the
roots when setting the tree. Putting 2 to 3 pounds of high
calcium lime on the soil scheduled to be returned to the
planting hole may improve the calcium level of the trees for
2 or 3 years. Haul in some rich soil if the soil is not good.
A half bushel of good soil with 2 to 3 pounds of high cal-
cium lime mixed with it will help the trees off to a good
start.

Planting holes are most frequently dug with tractor
mounted augers. A 9-inch auger is suitable for trees on M.9
rootstock. However, a 12-inch auger is needed when the post
for supporting the tree is going to be placed in the planting
hole. A 2-foot auger orbackhoe is best on a poorly prepared
soil and for trees on rootstocks other than M.9.

Soaking the tree roots in water for 12 to 18 hours prior
to planting is a good practice. During planting, keep the roots
moist by covering them with wet burlap or canvas or keep
them in water to prevent drying. At planting, the broken
roots should be removed and the trees set in the holes so
that the largest roots, and if possible, the heaviest branched
side is toward the prevailing wind. Plant the tree with a slight
slant in the same direction. When planting on dwarfing root-

stock, the graft union after tree settling should be 2 inches
above ground line. Allow an additional 2 inches at planting
for tree settling.

After planting, the soil should be thoroughly tamped
around the roots so they will be in contact with wet soil. It
is not necessary to water trees unless it is extremely dry prior
to and after planting.

Opinions differ concerning the planting depth of 3-piece
interstem trees. Some suggest that these trees should be
planted with the lower graft union 2 inches above ground.
Other individuals suggest deeper planting with the top of
the interstem 2 inches above the ground. We have tried both
methods and have observed that when the rootstock portion
is less than 7 inches in length, shallow rooting can be expected
when the trees are planted with the lower graft union 2 inches
above the ground. The trees may be less vigorous than those
planted deeper (the top of the interstem 2 inches above the
ground) and frequently require support.

Four-piece trees can be planted 12 inches or more in depth
because the trees of this type may average 20 inches in length
between the scion union and the top of the roots. However,
the trees should not be planted too deeply to prevent scion
rooting.

Placement of sand or gravel around the tree base after
planting will help stabilize the tree. It also helps to keep the
area dry and thus reduces the danger of collar rot. Do not re-
move soil from around the trunk, place the gravel or sand on
top of the soil. (The trees will not scion root in these materi-
als.) When the wind causes the trunk to sway, the gravel will
trickle down and around the trunk, thus helping to stabilize
the tree. Also, this will prevent the formation of an open

area around the trunk where water will collect and contribute
to crown disorders.

Supporting Trees

Tree support is now accepted as a standard procedure in
apple growing. The need for tree support is dependent on
rootstock, cultivar, soil type, and site. For example, all trees
on M.9 need support. Delicious on IV1.7 need support whereas
Mcintosh on this rootstock is generally well-anchored on
deep, well-drained soils. On windy sites, it may be advan-
tageous to provide at least temporary support for all trees
on M.26 and M.7 rootstocks. Support methods mclude:
(a) temporary basal support which is practiced so that the
tree can establish a strong lateral root system; (b) permanent
support by posts; and (c) permanent support by a trellis.

Temporary support. This can be provided with a 3-foot long
hardwood stake driven 2 feet into the ground next to the
trunk at planting time. Plastic ties, nylon ties or wire can be
used to fasten the tree to the post. When wire is used, the
wire around the tree should be covered by a section of inner
tube, a section of plastic hose, or cloth to prevent tree injury.
Temporary support may be necessary for the first 5 or 6
growing seasons.

Permanent post. Pentachlorophenol-treated (penta-treated)
or creosote-treated posts are used for trees on l\/l.9 root-
stocks. These should be allowed to weather for a year
before use because of possible injury to the trees by the
creosote or penta. The posts should be 8 to 8/4 feet in
length, at least 2 to 2y2 inches in diameter at the base, and
set V/2 to 2 feet in the ground (Fig. 4). Soon after planting,

Fig. 4. A planting of trees on M.9 rootstocks after 3 growing seasons. The trees are individually supported by an 8-foot post
set 2 feet in the ground.

Fig. 5. In this orchard, the end posts are stabilized with a
wire extending from the posts to an anchor bolt.

Fig. 6. End post of trellis using monofilament. A hole was
bored in the end post for the insertion of the "feed
through" device for the monofilament. The "feed
through" device secures the monofilament and
eliminates the need of stapling the monofilament.

plastic or nylon ties should be looped in a figure 8 around
the tree and post at about 2-foot height to provide tree
support. In older plantings, 3 to 5 of these ties are used
per post for tree support and to keep the leaders vertical.

Trellis. Training apple trees to a trellis is quite similar to train-
ing grape vines to the Kniffin system. The trees are supported
on trellises of 8 to 9-foot long preservative-treated posts set
2 to 272 feet in the ground and perhaps spaced 24 feet apart
in the row. The end posts are stabilized with a wire extending
from about the height of the top wire of the trellis to an
anchor bolt (Fig. 5) or to a "dead-man" buried 3V2 to 4 feet
deep and 4 to 5 feet from the post. No. 9 galvanized wires
or plastic wires stapled to the posts or passed through the
interior of the posts complete the trellis (Fig. 6). The bottom
wire generally is 2 feet above the ground, while the others
are spaced 12 to 18 inches apart above it depending upon
the height of the posts (Fig. 7).

Care of Trees the First Year

Heading the newly planted tree. It is difficult to find agree-
ment on this very important phase of tree training. No. 1
trees of non-spur types (standard types) frequently are head-
ed at 30 to 36 inches or not at all if planted early. Spur-type
trees which don't branch as readily as standard types are
generally headed at 28 to 30 inches. Heading spur-type trees
rather severely should promote branch development which
might otherwise be inadequate in number. (The lower the
tree is headed, the greater the number and length of the
branches.) Regardless of heading height, both spur and stan-
dard types (non-spur) may still fail to produce a sufficient
number of branches the first year in the orchard. As long as
leaf size and color are good, the trees should develop good
lateral branching the second season.

When newly planted trees are not headed severely enough,
they usually develop branches that are too high. The next
pruning season, the trees may have to be headed again to
induce branching between the height of 20 to 30 inches above
ground level (the desired height of the lower permanent
branches). Thus a year is lost.

Pruning in the planting season. As a xu\e, all desirable branch-
es on the free afp/anf/nff should be left unpruned. An excep-
tion to the rule would be when a tree has one large branch.
This should be removed because it may cause one-sided
branch development on the tree by inhibiting the growth of

Fig. 7. Tree being trained on a trellis. In this orchard, the
posts are set 22 feet apart. The bottom wire is 2 feet
from the ground with 2 wires above spaced 22 to 24
inches apart. The depression at the base of the trees
should be filled in with soil, sand, or gravel to prevent
accumulation of water.

]

Fig. 8. Mcintosh on M.26 after one growing season. This
tree had one strong branch at planting that should
have been removed. It now competes with the leader
of the tree. It should be removed and the leader
headed at 28 to 30 inches to stimulate branch devel-
opment. Fig. 9 shows the same tree after pruning.

other branches or it may compete with the leader (Figs. 8
and 9).

Pest control. An essential for optimum growth in compact
orchards is adequate pest control. Too often, young plantings
are sprayed inadequately because of the practice of applying
what is left in the tank after spraying bearing orchards. This
is an unwise practice considering the high cost of establishing
orchards and the need of early returns on the investment.
Growers with substantial acreage of young plantings may
find smaller and less expensive spray equipment than com-
monly used in older trees a good investment.

The most common pest problems in young apple orchards
in Massachusetts are scab, sucking and chewing insects, and
tree borers. Generally, for the first 3 years, 7 to 10 sprays
annually are required to control these pests. The entire tree
should be sprayed including the trunk. It is well to remember
this when selecting mouse guards because some types inhibit
good spray coverage as well as sunlight and air movement.

Young plantings can be sprayed on an alternate row

Fig. 9. The same tree as in Fig. 8 after pruning.

basis (spraying every second or third row and then reversing
the order of travel the next spray). The first growing season
of the planting, the dosage rate per 100 gallons can be 25%
of that recommended for bearing trees. The dosage rate
should be increased annually and by the fourth growing
season, a full dosage rate and spray schedule is recommended.
For information concerning pest control, contact your
County Extension Office. Pest control charts are revised
annually.

Fertilization. Lime but not fertilizer or manures can be put
in the planting hole with the roots. Lime can be added by
throwing 2 to 3 pounds of high calcium (Ca) lime on the soil
destined to be returned to the planting hole. A nitrogen (N)
fertilizer, a complete fertilizer, or one containing N, potas-
sium (K2O) and minor elements, should be applied after a
rain has firmed the soil around the roots of the newly planted
tree. Fertilize at the rate of 1/4 to 1/3 pound of ammonium
nitrate (33% N) or its equivalent by spreading lightly in a
wide circle around the tree (8 to 12 inches from the tree
trunk). Calcium nitrate is gradually replacing ammonium
nitrate as the common source of nitrogenous fertilizer be-
cause of low Ca levels in Massachusetts apple orchards.

Chemical weed control. Paraquat can be applied anytime
during the growing season under newly planted trees and
dichlobenil is safely applied in the late fall or early winter
at the end of the growing season. Apply paraquat at the rate
of 1 quart plus spreader per acre in mid-May and again in
mid-July taking necessary precaution against hitting the tree
with the direct spray or spray drift. Drift can be a major
problem when applying herbicide sprays. To reduce this
problem, you can use a foaming agent (adjuvant) with the
spray, avoid spraying when the wind is greater than 5 miles
per hour, avoid high pressures, and use nozzles that produce
coarse sprays with a minimum of fine droplets. A flooding
flat nozzle is particularly good for drift control and is de-
signed to operate at 15 to 20 psi.

Dichlobenil (Casoron*) should be applied at the rate of
100 to 150 pounds of 4% granular per acre. Its use is de-
scribed elsewhere in this publication.

Guards for mouse protection. Encirclement of tree bases
with hardware cloth guards to prevent mouse injury has been
a standard practice for many years. Hardware cloth must
have 3 or 4 wires to the inch to be mouse-proof. The guards
should be 6 inches in diameter and 18 inches in height. They
should be set in the ground on top of the tree's root crown.
Hardware cloth is expensive and has to be cut to the desired
dimensions.

Plastic-lined mouse guards can be purchased precut from
a local distributor. They are cut to form a circle 3 inches in
diameter and 18 inches in height or a 6 inch circle with 10
inch height.

Plastic mouse guards have become popular the last several
years because they are more economical than hardware cloth
or plastic-lined mouse guards. However, they shelter insects
and should be examined annually for constriction of trunk
growth.

Pruning

At this point, it is well to recognize the fact that pruning
procedures cannot be fully and accurately described. Fur-
thermore, no two trees, which appear similar at planting
time, grow alike even when subjected to similar pruning and
training procedures. Cultivars differ in growth characteristics
and their response to pruning. Lastly, rootstocks, soil and
growing conditions influence tree vigor and pruning and
training requirements of trees. At best, all we can do is dis-
cuss the basic principles for training and pruning and you
will have to learn the finer details by experience.

We suggest training and pruning trees to obtain and main-
tain a conical shape (Christmas tree shape) because this
form allows better penetration of sunlight into the trees
and light distribution along the sides of trees. A conical tree
shape is only possible with a central leader tree and only
possible by removing and/or shortening the strong branches
in the upper part of the tree and retaining the shorter, weaker
branches. Presently, many trees in our orchards have large
branches in the upper third of the trees which inhibit light

penetration into the lower section of the trees.

In the past, the main objective of pruning an apple tree
was to produce a large percentage of Extra Fancy apples at
lower costs. This is still the prime objective but many growers
are now attempting to obtain the benefits of early, heavy
production by closer spacings of compact trees. As a result,
the problem has arisen of trying to contain the trees within
their allotted spacings especially when thecultivar-rootstock-
soil has not been properly matched.

Training and pruning of trees becomes increasingly impor-
tant as planting density increases. Growers lacking time to
do detailed pruning and training, as being suggested for medi-
um and high density plantings, would do well to establish
only low density plantings. Such a planting system is rela-
tively easy to manage and not so sensitive to variations in
soil conditions, errors in pruning, and other management

procedures as are medium and high density plantings

Season to prune. Commercial growers commence pruning
some types of fruit trees in January, but home orchardists,
because of limited tree numbers, can wait until the arrival
of milder weather. Pruning may be done through the blos-
soming period but late March or April is preferred. Water
sprouts on apple trees should be removed in mid-summer
and dead or diseased branches can be removed whenever
they are present.

Pruning systems. It appears logical to suggest the following
pruning systems, based on orchard density, for Massachusetts
orchards.

1. Low density orchards: minimal containment of tree
spread and height.

2. Low density orchards: containment of tree height.

3. Medium density orchards: containment of tree spread
and height.

4. High density orchards: staked ortrellised.

Pruning low-density orchards with minimal containment of
tree spread and height This system involves pruning tech-
niques used in the past and described in countless pruning
bulletins. The tree has a central leader and pruning involves:
(1) the selection of desirable scaffold limbs; (2) the removal
of undesirable limbs to eliminate whorls of branches and
thus permitting only one branch to develop at a given level
as shown in Fig. 10A; (3) maintaining the dominance of the
leader by suppressing or removal of competing leaders;
(4) restricting too rapid development of certain scaffold
limbs by heading-back to an outward growing horizontal
shoot or branch; and (5) on bearing trees, the elimination

^Growers may be able to increase production per man hour
and per acre without the problems encountered with vigor-
ous cultivars on semi-dwarf rootstocks at close spacings if
M.26 and interstem trees prove reliable under our con-
ditions.

of those tree parts which tend to bear fruit of poor size and
color.

Limb positioning (described elsewhere in this publication)
is a very important practice on cultivars, such as Red Deli-
cious, which possess the inherent tendency to develop narrow
crotches.

The "novice" fruitgrower should purchase (fee 25 cents)
Leaflet No. 290 entitled "Pruning Fruit Trees in the Home
Orchard" from the Bulletin Center, Stockbridge Hall, Univer-
sity of Massachusetts, Amherst. This leaflet contains illustra-
tions, photographs, and discussions which will increase the
reader's understanding of basic pruning techniques.

Pruning low density orchards with containment of tree
height. Many growers would like to restrict tree height to
about 12 feet even in low density orchards. The central
leader and branch development on the central leader in the
upper portion of the tree requires considerable attention
in order to accomplish this goal. The following training and
pruning procedures for restriction of tree height \s suggested
for trial. These procedures involve the development of
branches in layers on the central leader and heading the cen-
tral leader annually (Fig. 1 0B) fe(/f/?of /7ea(y/>7g the past sea-
son's growth on scaffold limbs as shown in this figure. Tree
height can also be restricted by using pruning procedures
described under the previous heading and by annual heading
of the central leader as described below.

Fig. 10A. Two year old tree being pruned by standard prun-
ing procedures. The lowest limb should be 18 to
20 inches from the ground, all others spaced 4 to
8 inches apart vertically on the trunk and each
one about 90° around the trunk from the one
below it.

Fig. 108. Two year old tree being pruned as suggested by
the USDA. It has 2 layers of limbs. The leader
will be headed annually [heavy marks ( — ) indi-
cate heading cuts] . The one year old wood on the
branches is headed annually until branches on
which this wood is borne start to fruit.

First dormant season.

1. Select central leader and remove branches competing
with it (Figs 11 and 12). (This could have been done
in June of the first growing season.) See Fig. 13.

2. Head the central leader by removing % to V2 of its past

season's growth (Fig. 12).
p

a. When heading leader of a weak tree or one with

no lateral branching, be aware that the first level
of branches should be developed within the verti-
cal spacing of approximately 1 8 to 30 inches from
ground level.

b. If the leader and lateral branch development is
poor, head it regardless, developing both the first
and possibly some of the second level of branches
the following year.

3. Select lateral branches (3 to 5 if possible), well-spaced
vertically around the trunk for the first level of perma-
nent branches at the base of the leader. (These branches
could have been positioned with spring-type clothes-
pins during the first growing season.) Fig. 14 shows the
use of clothespins to position branches.

a. If only one branch has developed or the branches
are too high or low, remove them and start over.

b. If branches have developed on only one side, do
the same.

4. Branches lower than 18 to 20 inches from the ground
should be removed.

Second dormant season.

1. A well-grown tree will have branches on 2 and 3 year
old wood. However, most trees will not make sufficient
growth to make possible the selection of a second level
of branches 20 to 24 inches above the lower level of
branches at the base of the central leader.

2. Remove all shoots competing with the previous sum
mer's extension growth of the central leader. (This
could have been done in June of the previous growing
season. Also, it may have been possible to retain some
of these competing shoots if they had been positioned
with spring-type clothespins during the previous grow
ing season.)

3. Head the central leader by removing Va to V2 of its past
season's growth depending on tree vigor and the pres-
ence or absence of lateral branches on the previous
summer's extension growth of the central leader.

4. Remove all branches along the central leader for a dis-
tance of 20 to 24 inches between the uppermost branch
of the first layer of permanent branches and the top
of the leader. (This could have been done during the

"Heading— usually refers to cuts made into current season's
shoots or 1 -year-old shoots. Only part of this wood is re-
moved, leaving part of the same age wood on the tree.

Fig. 11. Jerseymac on MM 106 after one growing season.
Tine tree developed wide-angled lateral branches.
It is necessary to select one of the 3 upright branch-
es as the central leader and head the central leader.
Fig. 12 shows the same tree after pruning.

previous growing season.)

5. A few trees will have lateral branches on the previous
summer's extension growth of the central leader. On
these trees, it will be possible to select laterals for the
second layer of branches. Select 3 or 4 lateral branches
for this second layer allowing several inches vertical
spacing between branches. Remove excess branches.

6. Continue the selection of the first level of scaffold
branches at the base of the leader. Three to five
branches are needed. These should be well-spaced
vertically around the trunk and the lowest limb 18
to 20 inches from the ground.

7. Position the branches at the first level to an angle of
45° with wire or wood spreaders described elsewhere
in this publication. Those that developed the previous

Fig. 12. The same tree as in Fig. 1 1 after pruning.

growing season could have been positioned at that
time with spring-type clothespins.

8. Remove upright shoots (watersprouts) that may have
developed on the branches at the first level, branches
growing towards the center of the tree, downward, or
competing with the selected, permanent scaffold
branches.

9. Heading of branches may be required on some cultivars
to stiffen them and on spur-types to force lateral
branching.

Third dormant season

1 . A well-grown tree now has 2 distinct layers of branches
(the first at the base of the central leader and the sec-
ond 20 to 24 inches above the first layer) and possibly
the beginning of a third layer on the previous season's
extension growth of the central leader.

2. The previous summer's extension growth of the central
leader is pruned and competing shoots removed as de-

'■■ s

Fig. 13. A hormone is synthesized in the growing points of
the branches in the upper parts of the tree and
translocated downward. (The greater the amount
of hormone, the wider the branch angles.) There-
fore, crotch angles are relatively narrow in the
branches highest on the trunk where little or no
hormone reaches them from growing point above,
and they are progressively wider toward the base
of the tree as shown in this figure. Furthermore,
the smaller the supply of hormone, the greater the
growth. This is why the greatest growth was made
by the uppermost branches of the tree shown In
this figure.

scribed for the second dormant season.

3. Select 3 or 4 lateral branches, if they are present, on
the previous season's extension growth of the central
leader for the third level of branches. These should be
18 to 20 inches above the second level of branches.

4. Continue the selection of the second level of scaffold
branches (20 to 24 inches above the first level). Three
or four are needed and should be well-spaced vertically
(3 to 4 inch spacing) and the branches not directly

Fig. 14. Spring-type clothespins used on lateral shoots the
first growing season to position branches. The
clothespins could have been removed after 2 or 3
weeks. Note the plastic-lined mouse guard. The
gap at the bottom of the guard makes it ineffective
for mouse protection.

above one another.

5. Position the branches at the second level to an angle
of 45°.

6. Prune the scaffold branches in the first layer at the
base of the leader as described for the second dormant
season.

Fourth dormant season.

1 . At this time, scaffold branches should be well distrib-
uted along the central leader in layers. There should
be 3 distinct layers on well-grown trees and the start
of a fourth layer, depending on how well the tree has
grown.

2. The one-year-old and two-year-old sections of the

MOW TO GET THE HIGH DENSiTT TREE Off TO A GOOD STA«T
MEAVr MASKS SHOW WHERE PRUNING CUTS SHOULD BE MADE

1 •y*ar-old tt<fion Remove oil
competing thooti Heod back t«r-
minol thoor

7-voor-old techon Select and
head lateral branchet Remove
unneceitary loteroU

3-year-old lection Spread branch-
ei, remove forked tenn'noli *0 a
tingie thoot and heod that ir>oot
Head tide thoolt

4-vear old lection Spreod brorich-
et, remove forlred termlnoll to o
lingle iheet and head that ihool
Head tide thoott

S-yeor-old lectlon and older If
tree hat filled alloned ipare,
head back where neceiiar> into
7 year-old wood to on unheaded
lide ihool Avoid heading cute
into 1 -year-old ihooti until the
tree It fruiting well

Fig. 15. A diagram of the "constructive training" program suggested by Dr. D.R. Heinicke in USQfK Agriculture Handbook
No. 458 entitled "High Density Apple Orchards-Planning, Training and Pruning." (Reproduced with permission of
the author.)

central leader should be pruned as in the third dormant
season— heading the extension growth, removal of
competing lateral shoots, selection of branches for
the third level, and positioning of branches in the third
level.

3. The framework of the 2 lower levels of branches has
been established. Remove only water sprouts and
those branches which are growing toward the center
of the tree, or are competing with permanent scaffold
branches. Excessive pruning invigorates growth and
delays formation of fruit buds.

Care beyond the fourth year.

1. Prune to maintain the conical shape with short, weak
branches in top of the tree.

2. Head the central leader annually. If it gets too vigor-
ous, cutting into 2-year-old or older wood may be
necessary. The central leader above the cropping area
should not carry too many branches.

3. Try to develop new branches in the tree instead of
attempting to invigorate old wood.

a. Water sprouts that are growing in the direction
of a vacant area can be kept to fill that section
with bearing wood or as replacements for older
bearing branches. Positioning of these water
sprouts would be beneficial in many instances.

b. An occasional new shoot, growing at an angle
from a branch, can be retained to provide new
bearing wood for the future.

4. Cut all dead and diseased wood, all branches that have
a tendency to grow inward toward the tree's center,

and all water sprouts that are growing straight up,
whether in the center of the tree or from the upper
surface of side branches.

5. Drooping shaded wood that has become weak and
unproductive should be removed.

6. Where two branches are growing so close together
that one shades the other, the less desirable branch
should be removed.

7. All suckers at the base of the tree should be removed.

Pruning medium density orchards. A training and pruning
system for medium density orchards is described in Agricul-
ture Handbook No. 458 published by the USD A. ^ We have
no experience with this system in Massachusetts but since
there is grower interest in it we have attempted to describe
it below. The training and pruning procedures suggested in
Agriculture Handbook No. 458 (See Fig. 15) may be most
suitable for spur-type trees which branch less readily than
standard types.

Planting time.

1 . Head trees at about 28 to 30 inches.

^Agriculture Handbook No. 458 published in 1975 by the
USDA and entitled "High Density Apple Orchards-Plan-
ning, Training and Pruning." You can purchase this publi-
cation for 65 cents a copy from the Superintendent of
Documents, U.S. Government Printing Office, Washington,
D.C.

Fig. 16. Mac Spur on IV1.26 after 1 growing season. Since
only one branch developed at a low level (less than
18 inches from ground), it should be removed and
the tree headed again at 30 inches.

First growing season.

1 . When shoots average 3 to 6 inches in length:

a. Select central leader plus 3 to 5 potential branches
and remove all other shoots.

b. Remove shoot growth lower than 18 inches from
ground.

First dormant season.

1. Tree is now composed of new terminal shoot growth
(one-year-old section of tree) and the original whip
with lateral shoots (two-year-old section of tree).

2. Select the central leader and remove all competing
shoots.

3. Head the central leader by removing !4 to Vs of its
past season's growth. Head it to induce branching
that will be 18 to 24 inches above the branches at the
base of the leader.

Fig. 17. Same tree as in Fig. 16 after pruning. For those
with "courage" trunk renewal is a method of get-
ting weak trees to grow properly. This involves
cutting back the tree to a few buds to develop a
new trunk.

a. If leader development is poor, head it regardless
so that a strong leader will develop which can be
headed at an adequate height the following year.

4. Select 3 to 5 lateral branches, well-spaced vertically
around the trunk for the first level of permanent
branches at the base of the leader on the two-year-old
section of the tree.

a. If only one branch has developed or the branches
are too high or low, remove them and start over
(Figs. 16 and 17).

b. If branches have developed on only one side of
the tree, do the same.

5. Head each branch by removing % of the past season's
growth. This will keep the branches vegetative, stiff-
ened and encourage development of lateral side shoots
(Fig. 18).

Fig. 18. Heading cuts as advocated by the USDA induces lateral branching as illustrated in (A). Branches of this type have
greater fruiting potential than the unheaded branch shown in (B). Heading cuts to induce lateral branching may not
be essential on non-spur type trees. (Redrawn with the permission of Don R. Heinicke.)

Second growing season.

1. When current season's growth is 3 to 6 inches long,
remove those shoots competing with the terminal
branch extension and the central leader.

Second dormant season.

1. Tree now composed of 1, 2 and 3-year-old sections
with one or two levels of branches (Fig. 10B).

2. The 1 and 2-year-old sections are pruned the same as
the first dormant season. This consists of removing
shoots competing with extension growth of the leader
and selecting 3 to 5 lateral shoots to form the second
level of branches on the central leader. The second
level should be 18 to 24 inches above the first level at
the base of the leader. Head the leader and lateral
shoots (branches) by removing '/= and % of their past
season's growth, respectively.

3. In the 3-year-old section:

a. Position branches to open areas and spread to a
45° angle before pruning.

b. Thin excess shoot growth and maintain 3 to 5
lateral branches in the lower or first level.

c. Prune the lateral branches as if each were a central
leader tree.

1. Single out terminal shoot and remove compet-
ing shoots.

2. Head terminal shoot by removing Va of its cur-
rent season's growth.

3. Thin^'-' vigorous shoots growing upright on
the branch.

4. Head side shoots of the branch by removing '^
or less of the current season's growth. This
won't be necessary with some cultivars.

Third growing season.

1. Remove shoots the same as in the second growing
season. In addition, remove all vigorous upright shoots
developing on lateral branches.

nird dormant season.

1. The tree now is composed of 1,2, 3, and 4-year-old
sections with 2 or 3 levels of branches.

2. The 1, 2, and 3-year-old sections are handled as
described before. Be sure to allow adequate space
between limbs developing one above the other.

3. Some of the headed shoots on the 3-year-old section
will have lateral shoots develop below the point of

^ ^Thinning refers to the removal of branches in a portion
of the tree or throughout the tree to reduce competition
between limbs and permit greater light and spray pene-
tration.

heading. If too many develop, remove some (thinning
cuts), keeping those more horizontally positioned.

4. Do as little pruning as possible in the 3-year-old section
of the tree. Tfie leader Is the only terminal requiring
heading each year

5. In the 4-year-old section, reduce the number of head-
ing cuts:

a. Remove all shoots competing with terminal
growth.

b. With regard to shoots developing on the branches:
remove over-vigorous ones, head lightly some with
moderate vigor, and leave the rest of moderate
and weak vigor shoots unheaded.

c. Where side shoots were headed the year before,
cut (thin) into 2-year-old wood to a weak side
shoot or a bud, removing the vigorous terminal
growth.

6. Fruiting should be confined to the 4-year-old section.

Fourth growing season.

1 . Remove fruit from central leader and ends of branches
to maintain tree form (may be necessary in third sea-
son for some cultivars). Follow procedures practiced
in the third growing season.

Fourth dormant season.

1. Tree is now composed of 1, 2, 3, 4, and B-year-old
sections with two to four levels of branches depending
upon how well the tree has grown.

2. Encourage fruiting rather than growth, so, do as little
pruning as possible.

3. If possible, avoid heading into 1-year-old wood in
sections where fruiting is to be encouraged.

4. In 5-year-old section:

a. If tree has filled allotted space, head back where
necessary into 2-Year-old wood to an unheaded
side branch.

b. Avoid heading cuts into 1 -year-old wood until
the tree is fruiting well.

Care beyond the fourth year.

1 . Keep a vegetative terminal shoot on the central
leader. It may be necessary to cut back into the older
wood to renew the terminal shoot.

2. Make mainly thinning cuts by removing an entire
branch or cutting back into older wood to a side
shoot (1 -year-old wood) or branch.

3. Follow procedures 4 to 9 as outlined in section
entitled "care beyond the fourth year" for low den-
sity orchard with containment of tree height.

4. Cultivars, such as Cortland and Golden Delicious
with flexible wood, often need to be headed back to

a more horizontally growing branch near the trunk.
Branches of Cortland tend to droop and this cultivar
has a tendency to lose its dominant central leader.
Thus, particular attention must be given to keeping
the leader dominant. Mcintosh and Jerseymac should
present no serious problem if well trained during the
first 4 years. Cultivars, like Delicious, Early Mcintosh,
and Macoun, need limb positioning because they are
inclined to develop strong upright limbs.

Pruning high density orchards with trees stai<ed. Trees on
M.9 are frequently trained as slender spindles in Europe and
in western New York State. Tree shape is conical having a
permanent frame of branches at the base of the leader, and,
above this frame, short fruiting branches arranged around a
vertical leader which is supported by a post. The size of the
permanent frame of branches depends on the planting dis-
tance, being larger the greater the planting distance.

High tree numbers per acre using M.9 as the rootstock is
only possible with weak (small) frames. Therefore, pruning
is minimized in the early life of the tree to encourage early
cropping. On bearing trees, vigorous branches are completely
removed to maintain low vigor on the trees. Thus, the com-
bination of M.9 rootstock, minimum pruning, early bearmg,
and the removal of vigorous branches all contribute to weak
growth and permits close tree spacings.

The following procedures are suggested for training trees
as slender-spindles and are for trial only. Undoubtedly,
experience will prove us wrong on some procedures.

Planting time.

Head Mcintosh trees and other vigorous varieties at 36 inch-
es—a weak growing variety should be headed at 30-32 inches.
Remove all branches lower than 16 inches from the ground.
Other branches are best left unpruned except if they are
badly placed, for instance all are on one side of the stem or
where there is only a single vigorous branch. When all the
branches are on one side of the stem they should be thinned
out. If there is only a single, vigorous branch, it should be
removed to avoid lopsided development of the tree.

First growing season.

When the extension shoots at the top of the tree are 6 to 8
inches long, remove the upper-most extension shoots (gen-
erally 2) and leave a weak upright growing lateral for the
leader. Spread branches with spring-type clothespins.

First dormant season.

1. In developing the slender-spindle, the goal should
always be to weaken the growth in the top of the tree
and encourage the production of fruiting branches.
Thus, remove the strong vertical leader and use a weak-
er competitor lateral as the new leader if not done the
first summer. The branch selected is not necessarily
the first one below the leader, especially if the first
lateral branch is growing very strongly. Similarly, if
vigor in the lower part of the tree is weak, it is best

to cut back to a lower upright-growing lateral to stimu-
late growth of the laterals for the lower frame. When
there is no suitable lateral to serve as a replacement
leader, it will be necessary to retain the central leader.
It should be pruned back only if the overall tree is
weak. Any competing lateral immediately beneath
the central leader should be spread or removed.

2. If desirable branches fail to develop 24 to 36 inches
above the ground, reduce the height of the leader by
1 to 1 2 inches. Cut at a vertical 1 -year-old shoot suit-
able as a new leader. This is necessary to encourage
formation of strong lower branches.

3. Four or five strong wide-angled branches are needed
in the lower 1/3 to 1/2 of the tree. However, it is
better to have too many than too few. The extra ones
can be removed later.

4. Branches lower than 24 inches should be removed.
Second dormant season.

1. Again remove the strong vertical leader and use a
weaker competitor as the new leader. If the leader is
too vigorous, cut back to a vertical 2-year-old branch
(Figs. 19 and 20). The procedures of removing the
strong leader will give a zig-zag growth pattern to the
central leader and reduce its vigor

2. When limb positioning is necessary, perform this pro-
cedure at this time.

Third dormant season.

1. Repeat the procedure followed the second dormant
season.

2. Remove, don't head back, vigorous branches in the
upper part of the tree. This is necessary for the main-
tenance of a conical-shaped tree. Therefore, the bran-
ches in the upper 1/2 of the tree must be shorter and
weaker than the permanent branches at the base of
the leader. Secondly, heading-back scaffold branches,
rather than their complete removal, will stimulate
undesirable lateral and vertical growth.

3. Limb positioning is best avoided by retaining only the
weakest shoots toward the top of the tree. All pruning
should be directed toward reducing the vigor in the
upper part of the tree and avoiding heavy growth.^ '

Fourth dormant season.

1 . The top of the tree should be cut back to a 2 or more
year old side branch and not, as in previous years, to

ll Summer pruning (aftergrowth stops) is the preferred time
to make thinning cuts because less stimulation of growth
follows pruning at this time. However, avoid all unneces-
sary pruning until the tree is in heavy production.

Fig. 19. Mcintosh on M.9 after 3 growing seasons in the
orchard. The central leader should be headed to a
competitive lateral. Repeated replacement of the
central leader by a weaker competitive lateral
should weaken the growth in the upper part of the
tree. Fig. 20 shows the same tree after pruning.

a 1 -year-old shoot. Cutting back to a 1 -year-old shoot
should be done only when the shoot is weak and wide
angled, otherwise the growth of the top may become
too vigorous.

2. Strong growing branches 1 -year-old and older toward
the top of the tree should be selectively pruned. This
is necessary if vegetative growth and fruit quality in
the lower parts of the tree are to be maintained.

3. At this time, it may be necessary to remove some
branches at the base of the leader, depending upon
its vigor, because loss of the dominance of the central
leader is possible if a balance is not maintained.

4. Continue to maintain the conical tree form.

Pruning fifth year and thereafter.

^ . Pruning will be similar to the fourth year.

Fig. 20. The same tree as in Fig. 19 after pruning.

2. Do branch renewal by complete removal of excess
branches. Leave a short stub when removing the
branch since this encourages the growth of a replace-
ment branch. However, branch replacement may be
more successful on the upper portion of the leader
than on its basal portion.

3. Maintain a conical tree form.

4. On weak growing varieties like Golden Delicious, thin
wood pruning is necessary to attain fruit size. Cortland,
which bears much fruit terminally, will require numer-
ous small cuts to remove the excess of twiggy growth
which develops toward the outside of the tree. On
Mcintosh and Delicious, it will be necessary to prune
much vigorous wood growing above a horizontal posi-
tion. However, whenever possible, remove just the
drooping wood because undesirable upright growth
will develop.

Pruning high density orchards on trellis. Trellises for sup-
porting apple trees differ throughout the world as does
training methods employed for trellised-trees. We described

a trellis of 4 wires in the section on "supporting trees."
A trellis may be constructed to acconnmodate 3 to 6 wires
and the top wire may be e'A to 10 feet above the ground.
The height of the top wire is determined by the harvesting
method. In Massachusetts all picking from trellised-trees is
done from the ground, thus the top wire is 6 to 7 feet from
the ground. In other areas, the height of the tree wall on
trellis may be 12 feet and the fruit are picked from platforms
or short ladders.

Erection of the trellis is expensive. Your County Exten-
sion Service can supply you with names of local growers
who have trellises. You should visit these growers to obtain
ideas on construction and training of trees on trellises. Also,
your County Extension Service can supply you with names
and addresses of individuals to write in other areas to obtain
information on trellising. Perhaps the most costly error in
trellising is insufficient spacing between rows because of the
permanency of the trellis.

The trellis can be constructed in stages over the first 3
years after establishment of the trees or totally at a conve-
nient time. However, the posts and the bottom wire should
be in place soon after planting to support the developing
lateral branches and the central leader. A variety of systems
can be used to train trees to a trellis (Fig. 21). Our experience
is too limited to judge which system or systems are best.
However, a simple system for a 4-wire trellis involves training
8 limbs per tree to the trellis— 4 on each side of the main

leader— by twisting the limbs around the wire 1 or 2 turns.
Spring-type clothespins, plastic ties, nylon ties, or baling
twine can be used to hold the branches In place.

At planting, head the trees 17 to 18 inches above the
ground to induce branching below the first wire. Two bran-
ches are selected during the growing season and these plus
the extension growth of the central leader are tied to the
bottom wire. To prevent restriction of growth, do not bend
the branch downward to a level that is lower than its point
of attachment to the trunk. The branch is in the best position
when it originates several inches below the wire to which it
will be tied. All but the 2 selected branches are removed
in order to maintain a dominant central leader.

Pruning in the succeeding years of training will be similar
until the tree has 8 limbs trained to the trellis— 4 on each
side of the main leader. When the central leader extends
higher than the top wire, it can be bent in one direction and
tied to the top wire or be removed just below the top wire.

Each year, shoots will arise from the tied branches; some
should be (a) removed to allow better light penetration into
the tree; (b) others should be bent and tied to the wires;
(c) others should be headed back to maintain tree width in
the row to 3-4 feet; and (d) others should be used as replace-
ments for older branches that have become low in vigor.

Snow and ice may cause limb breakage on trellised trees
some winters.

Fig. 21. Apple trees can be trained as palmettes with horizontal branches (A) or palmettes with oblique branches (B) and by
other systems.

Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whaley
Director
Cooperative Agricultural Extension Work
Acts of May 8 and June 30, 1914

POSTAGE PAID
S. DEPARTMENT OF
AGRICULTURE

AGR 101

Official Business
Penalty for Private Use, $300

BULK THIRD CLASS MAIL PERMIT

Available to the public without regard to race, color or national origin.

FRUITpr
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 42 (No, 3)
MAY/ JUNE 1977

TABLE OF CONTENTS

Suggestions for Fertilization of Apple Trees in 1977

A One-Two Punch for Weeds in Strawberries

Reasons for Deformed Strawberry Fruits

Why Irrigation for Strawberries?

Alternate Row Spraying for Apple Pests

Supplement —

Establishment and Management of Compact Apple
Trees - Part IV (4 pages)

SUGGESTIONS FOR FERTILIZATION OF APPLE TREES IN 1977

W.J. Lord and Mack Drake
Department of Plant and Soil Sciences

It should be recognized from the start that it is not possi-
ble to give specific suggestions for fertilization in an article
of this nature. Therefore, the suggestions below merely serve as
a guide to the fruit grower for determining the fertilizer program
in his orchard. It is well to remember that foliar applications
of nutrients are merely supplements to soil applications.

The 1977 fertilizer program will require more than usual con-
sideration because of winter injury to the trunks of Mcintosh trees
and some Delicious trees in January, 1976, and due to variable
fruit set this past summer.

The bark on the winter-injured tree trunks in some instances
split but more generally just pulled away from the wood. Fortu-
nately, most growers became aware of the injury in March and April
and stapled or tacked the bark to the wood. Although the damage
was repaired, this past fall the leaves on many of the winter-
injured trees were light green or reddish in color in comparison
to those on non-injured trees. Since the trees have been weakened,
it is suggested that trees severely winter injured in 1976 be
sprayed in 1977 v\:ith urea (5 pounds/100 gallons) at about first
cover. Apply as a separate application.

Fruit set was variable in 1976 with a light crop of Mcintosh
in some orchards and a large crop of Delicious in many orchards.
Regarding this, it is well to remember that the bloom and the early
vegetative growth in 1977 will be made largely at the expense of
stored foods. Trees which had only a partial crop in 1976 should
have a considerable reserve of nitrogen (N) available for utiliza-
tion this spring. Therefore, one should reduce N applications in
those blocks that had a light crop in 1976 . To the contrary, trees
that had a heavy crop in 1976 and/or those that had winter injury,
may be low in available N for utilization this spring.

Nitrogen (N) . The best guide to N needs of your trees is leaf an-
alysis combined with observations of tree vigor, fruit set, and
fruit color. Growers definitely are using less N on Mcintosh than
in the past because we need medium-sized, well-colored apples with
long storage life. Some growers have now omitted N in mature
Mcintosh blocks for 5 to 8 years with no apparent harmful effects.

Young vigorous trees are troublesome when they start bearing
a crop because of excessively large, poorly colored fruit and poor
keepability of fruit in storage. The reduction or omission of N
is frequently essential. This proceedure plus limb positioning

2 -

(spreading) may be needed on vigorous young Delicious trees to en-
courage bloom and fruit set.

Apply sufficient N to keep bearing Delicious trees vigorous.
N levels of 2.2 - 2.4% in bearing Delicious trees are probably sat-
isfactory because it is necessary to keep the tree vigorous in or-
der to produce large-sized fruits. Furthermore, obtaining suffi-
cient red color on the newer strains of Delicious is not a problem.

The N requirement can be met by applying calcium nitrate, am-
monium nitrate or urea sources of fertilizer N or a "complete" fer-
tilizer. (Growers concerned about bitter pit and/or cork spot may
wish to rely on calcium nitrate as the source of N.) However, the
phosphorous (P) in the complete fertilizer is not needed in our
orchards. Therefore, purchase a prepared mix that contains no P
or purchase an N and a K fertilizer and mix them prior to applica-
tion or apply them separately.

Potassium (K) : The K requirements of apple trees with a large crop
are high because the fruit utilizes about 3 times as much K as N.
Since the quantity of K stored by the tree is extremely small, it
seems important to supply adequate K this spring on trees that had
heavy fruit set in 1976.

The requirements of apple trees for K (expressed as K2O) based
on potential yields are as follows: (a) less than 15 bu: 1.3 lbs/
tree; (b) 15 to 25 bu: 1.3-2.7 lbs/tree; and (c) more than 25 bu:
2.7-4.3 lbs/tree. It is necessary, however, to maintain a balance
among the essential nutrients for apple trees. For example, exces-
sive levels of K can reduce both leaf and fruit Ca. Therefore, w e
strongly urge that you participate in our leaf analysis program to
more accurately determine the K needs of your apple trees.

Calcium (Ca) : It is very difficult to increase Ca content of apple
trees and fruit. Although foliar sprays of Ca solutions have been
shown to reduce bitter pit, they have not eliminated it. A major
problem is that Ca in the soil moves very slowly into the tree and
most of it is quickly tied up in an insoluble form. We suggest,
the following measures to increase Ca content of apple leaves and
fruits.

A. Continue to apply 3 tons of limestone per acre every 2 to
3 years. Where high magnesium lime was used in the last
application, the use of a more soluble high Ca, low Mg
lime (5-7% MgO) will act more rapidly and will provide
more Ca.

B. Use calcium nitrate as the source of nitrogenous fertiliz-
er. Calcium nitrate increases the level of soluble soil
Ca more quickly, increases the downward movement of Ca and
raises the pH of the soil.

- 3

C. Apply foliar sprays of calcium chloride CCaClo) starting
about 3 weeks after petal fall and repeat at z-week inter-
vals, totalling 6 to 8 applications. Apply 6 to 8 pounds
CaCl2/acre/spray until mid-July. After mid-July, apply
12 to 18 pounds /acre/spray. Sprays may be applied dilute
or on a trial basis up to 6X concentration. Preliminary
observations indicate that CaCl2 can be added to the cover
sprays of pesticides. However, growers desiring to com-
bine CaCl2 with their cover sprays should do it on a trial
basis only . When combining with cover sprays, add CaCl2
last to the spray tank. If weather conditions permit go-
ing over 14 days without a cover spray, use CaCl2 spray
alone. If foliar injury from CaClo occurs, don't apply
again until after substantial rainfall (an inch or more).
Do not mix CaCl2 and Solubor* in sprays.

Magnesium (Mg) : The requirements of trees for this element can
best be met by maintaining an adequate dolomitic liming program.
Since it takes years before lime is effective in correcting Mg
deficiency, Epsom salt sprays can be used to help correct the con-
dition. Apply 2 to 3 sprays at the rate of 15 to 20 lbs per 100
gallons of water at the time of calyx, first cover and second cover
sprays. To avoid possible incompatibilities, the Epsom salt sprays
should not be combined with the regular pesticide sprays. Don' t
apply Epsom salts or a lime high in Mg unless leaf analysis or vis -
ual observation indicate low Mg levels . Mg can suppress Cal

Boron (B) : This element can be supplied to apple trees either by
foliar or soil applications. Use the most economical and conven-
ient method. However, it is safest to apply all elements as a fer -
tilizer except m emergency situations .

Soil applications of boron (B) should be applied to orchards
every 3 years. The rates of application per tree vary with age and
size. In low density orchards, apply 1/4 pound of borax (11.1^
actual B) or its equivalent under young trees coming into bearing,
1/2 to 3/4 pound to medium age and size trees and -3/4 to 1 pound
to large or mature trees. Be sure to note the percent actual B in
the fertilizer being used to supply this element . B containing fer-
tilizers vary from approximately 11 to 2T1 actual B.

In medium and high density orchards (US trees/acre or higher] ^
it might be best to apply B on an acre basis. We suggest the fol-
lowing rates per acre of borax (11.11 actual B) or its equivalent:
(a) trees 4 to 7 years of age - 12 lbs; (b) trees 8 to 15 years of
age - 12 to 24 lbs; and (c) trees 16 to 30 years of age - 24 to 4R
lbs.

When the soil application of B is followed by a wet spring, it
may be advisable to apply 2 foliar applications of B the following
year.

*Trade name

- 4 -

Many growers now rely on annual foliar applications of B.
The usual practice is to add Solubor* to the first 2 cover sprays.
Fertilizer grades of borax may contain grit and should not be used
in a sprayer. Mature trees should receive 4 pounds of Solubor*
per acre each year. Consequently, the goal is to apply about 2
pounds per acre in each of the 2 applications. For young orchards,
the addition of 1/2 pound of Solubor* per 100 gallons (dilute basis)
to the first 2 cover sprays meets the B requirement of these trees.
Reports of New York State indicate that sprays can be concentrated
up to 8X with satisfactory results.

Leaf samples from orchards treated with Solubor* have indicated
adequate leaf boron levels but the fruit was deficient in this ele-
ment . Whether or not B applied as a fertilizer more adequately
meets the B requirement of apples than foliar-applied B is not known
by us .

Manganese (Mn) : This element is deficient in some apple orchards.
Apple leaves having Mn deficiency have interveinal fading of chloro-
phyll with the veins remaining green. The use of manganese-zinc

fungicides may be of value in orchards low in Mn or zinc or both
elements .

Zinc (Zn) : Based on optimum levels of Zn established by some states,
some of our orchards are low in this element. Massachusetts growers
have not used zinc sulfate sprays applied at the "green-tip" stage
of bud development to increase zinc levels but some use manganese-
zinc containing fungicides. These appear to be increasing Zn levels
in our orchards.

*Trade name

***************

A ONE-TWO PUNCH FOR WEEDS IN STRAWBERRIES

Dominic A. Marini
Southeast Regional Fruit and Vegetable Specialist

To minimize weed problems in new strawberry beds, some growers
are utilizing a one-two punch of DCPA (Dacthal*) followed by Chlor-
oxuron (Norex* or Tenoran*) with excellent results. DCPA is applied
at transplanting. When DCPA begins to lose its effectiveness, after
6 to 8 weeks, chloroxuron is applied when broadleaf weeds are less
than 2 inches tall. Where galinsoga is a problem, it should be ap-
plied before the weed exceeds 3/4 of an inch.

DCPA and chloroxuron complement each other nicely. DCPA con-
trols annual grasses, and some broadleaf weeds including lambs

*Trade name

5 -

quarters, chickweed and purslane, while chloroxuron controls most
broadleaf weeds including galinsoga, but is weak on grasses. While
DCPA must be applied pre-emergence to weeds in order to be effec-
tive, chloroxuron may be applied either pre- or post-emergence.

For best
moist, clod-f
and before we
or irrigation
irrigation is
the chemical
lack of moist
seeds. Since
tall, moistur

results wit
ree soil bef
eds germinat

should foil

not availab
into the soi
ure to move

chloroxuron
e is not so

h DCPA, it should be applied to smooth
ore or immediately after setting plants
e. From 1/2 to 1 inch of water from rain
ow within 1 week of application. Where
le, shallow pre-plant incorporation works
1 reducing the risk of failure because of
it into contact with germinating weed

kills germinated weeds up to 2 inches
critical for it to be effective.

Where this one-two punch is empl
is reduced to a minimum. However, on
ter heavy rains, most growers cultiva
plants start producing runners to fac
this time, DCPA may be applied again
early post-emergence application of c
be applied without DCPA either pre- o
of chloroxuron within a week of DCPA
weather since injury may occur when t

oyed effectively, cultivation

soils that tend to pack af-
te to loosen the soil when
ilitate their rooting. At
pre-emergence followed by an
hloroxuron, or chloroxuron may
r post-emergence. Application
is not advisable in hot
emperatures exceed 85°F.

***************

REASONS FOR DEFORMED STRAWBERRY FRUITS

B.R. Boyce
Department of Plant and Soil Sciences
University of Vermont

Too frequently, strawberry growers find misshapen or deformed
berries in their fruiting fields. These berries are sometimes re-
ferred to by such names as "nubbins" or "catfaced fruit." By the
time this condition is observed, it is too late to do anything to
correct the problem.

The St
the pistils
tils and if
ically call
ly enlarged
and develop
rescence.
ternary bio
the fruit d
quaternary

rawberry fruit develops as a result of fertilization of
on the blossom. A flower may have several hundred pis-
fertilized, each pistil will develop into a seed, botan-
ed an achene. The edible part of the strawberry is main'
stem tissue. The primary blossoms have more pistils
into larger fruit than the later flowers of the inflo-
The later flowers, called secondary, tertiary and qua-
ssoms, usually have progressively fewer pistils and thus
eveloping from the tertiary and particularly from the
flowers are small, or maybe nubbins.

- 6

A perfectly shaped strawberry fruit requires pollination, fer-
tilization and subsequent seed development of each pistil in the
blossom. When conditions are less than optimum for these processes,
deformed berries can occur, the degree of deformity being related
to the number of achenes that do not form.

Present day strawberry varieties are self-fruitful and do not
require cross-pollination but there must be transfer of pollen from
the anthers to the stigmas of the pistils. Insects, primarily hon-
ey bees and solitary bees, are necessary for this transfer since
wind, rain, or gravity will not provide adequate pollination.

In a pollination study in which we caged plots of 'Catskill'
strawberries to exclude bees, very few fruits developed and those
that did were severely deformed. Blossoms in the uncovered plots
pollinated by bees and those that were hand pollinated inside the
covers, developed into normal berries. Berries in screened plots
that allowed rain penetration and air movement were no better than
those in the plots covered with polyethylene cages. This study
showed that adequate bee activity is necessary in commercial plant-
ings for high yields of well-formed berries. Thus, improper tim-
ing of insecticides may result in catfaced berries due to the kill-
ing of pollinating insects.

Frost injury may also deform fruit. The pistils are the most
frost susceptible part of the blossom. When all the pistils are
killed by frost, the fruit will not form. A light frost may kill
some of the pistils which results in a percentage of deformed ber-
ries.

Insect damage, especiall)^ that of the tarnished plant bug, is
probably the most common cause of deformed berries. The tarnished
plant bug feeds on blossoms and developing berries causing the ber-
ries to be misshapen and if not controlled, heavy losses may occur.
In a field study of tarnished plant bug injury at the University
of Vermont in 1975, unsprayed plots produced 10 to 60% less fruit
than those sprayed with an insecticide just before bloom. The
yield reduction was due to less fruit because of blossom injury by
the tarnished plant bugs and the presence of small deformed ber-
ries. Differences among varieties occurred, with 'Midway' being
injured less severely than the other varieties in the trial (Table 1).

Table 1. Average weight (gms) of strawberries harvested from sprayed
and unsprayed plots, University of Vermont, 1975.

Variety

Sprayed

Unspraye

Cgms)

Size reduction

28
30
3
27
32

(gms)

"Raritan'

9.2

'Sparkle'

8.0

'Midway'

7.6

'Redcoat'

7.5

'Catskill'

7.3

WHY IRRIGATION FOR STRAWBERRIES?

Dominic A. Marini
Southeast Regional Fruit and Vegetable Specialist

Irrigation is an important management tool for growers inter-
ested in obtaining consistent high yields of quality strawberries.
Strawberries can be a very productive and profitable crop with po-
tential yields as high as 18,000 quarts per acre. However, to ob-
tain such yields, careful attention to all cultural practices is
required, including maintaining an adequate moisture supply; Ample
moisture is essential for optimum fruit size and high yields, and
there are periods during every season when irrigation is necessary
on both the non-bearing and bearing bed. Economic studies have
shown that returns from irrigation are higher with strawberries
than with other crops.

Strawberries are shallow-rooted, with the greatest concentra-
tion of roots in the top 4 to 6 inches of soil and most of the
plant's moisture is obtained from the top 12 inches. The plants
require about one inch of water per week for optimum growth, from
the time plants are set until the crop is harvested.

Moisture is needed when the plants are set so that they can
become established quickly, make rapid growth, and start produc-
ing runners early. It is necessary to enhance rooting of runners
and to produce large plants with multiple crowns. Moisture is crit-
ical during August and September when fruit buds for the following
year's crop develop within the crown. In the bearing year,
adequate moisture is essential for maximum fruit set and to produce
large berries. If a bearing bed is to be carried over for another
year, moisture is necessary after mowing or renovating.

Irrigation is useful in other phases of strawberry production
management besides supplementing rainfall. Frost protection is one
of these. Hardly a spring goes by when strawberry crops do not suf-
fer some frost losses. Some blossoms are killed outright, while
others produce small, deformed, worthless fruit or "nubbins." Most
frost damage occurs to open blossoms, but unopened buds can be dam-
aged by low temperatures before bloom or before emerging from the
crown.

Most investigators report that strawberry crops can be protec-
ted from temperatures as low as 22°F, while a recent article in
American Fruit Grower states that irrigation saved a high percen-
tage of the bloom at 1 5 ° F .

Growers report using irrigation on as many as 18 nights during
a season for frost protection. As little as 50 gallons per acre
per minute or 1/10 inch per hour will provide frost protection.
Irrigation should start at 33 or 34°F before freezing begins and
should continue until the ice has melted and the temperature has

- 8 -

risen above freezing. A single 1/8 or 3/16 inch nozzle per sprink-
ler head will deliver enough water to protect the crop.

Irrigation also can be used to improve the performance of her-
bicides and fertilizers. Pre-emergence herbicides kill germinating
weed seeds, but in order to do so, they must come in contact with
the- seeds. From 1/2 to 1 inch of moisture is necessary within a week
after the herbicide application from the surface to move the chemical
into the soil to contact the germinating weed seeds. Moisture is
also required to dissolve fertilizer applied as sidedressi.ig and move
it down into the root zone of the strawberry plants.

As with other tools, irrigation must be used properly for max-
imum benefits. When used to supply moisture, irrigation should be
applied before wilting begins, so that plant growth will not be in-
terrupted. It should not be over-applied on fruiting beds or soft
fruit or fruit rots may result. Overwatering can cause waterlogged
soil and root injury, and may also leach nitrogen from the soil.
But properly used, irrigation can help to insure consistent high
yields of good quality strawberries here in New England, where ade-
quate, timely rainfall is so unreliable and losses from spring
frosts a likely possibility.

"ALTERNATE ROW SPRAYING FOR APPLE PESTS"

R. J. Prokopy, R. G. Hislop, and K. I. Hauschild
Department of Entomology

In the last issue of "Fruit Notes", we discussed the findings
of our 1976 studies on mite predators in Massachusetts apple
orchards. We presented information suggesting that some Massachusetts
growers having substantial numbers of mite predators needed to use
fewer miticide sprays than other growers having few mite predators.
Usage of certain insecticide and/or fungicide materials was apparently
harmful to the predators in some orchards. We suggested that growers
could reduce miticide usage by employing only those insecticides and
fungicides to which the mite predators seemed partially or fully
tolerant or resistant.

In this article, we discuss our 1976 findings on another poten-
tially useful method for reducing the amount of pesticide in
Massachusetts orchards: alternate middle of row spraying.

The alternate middle row spray treatment involves spraying alter-
nate halves of each tree on alternate spray dates instead of both
halves on all spray dates. For example, in applying the first cover
spray, the sprayer would be driven up the middle between tree rows A
and B and return down the middle between rows C and D, skipping the
middle between rows B and C. For the second cover spray, the sprayer
would be driven up the middle between rows B and C, down the middle
between rows D and F, and so forth. If this pattern were followed

- 10 -

We conclude from this first year of experimentation that an
alternate middle row spray program in Massachusetts shows promise
of effectively controlling the major pests that attack the fruit,
even in the face of potentially damaging pest pressure. This
effectiveness may stem in part from the adults of these pests
moving around the trees with sufficient regularity to contact the
sprayed portion. On the other hand, this program seems to be
less effective (though still possibly adequately so) against mites
and aphids, whose mobility is very limited. Keeping the tree well
pruned and the center open should enhance the effectiveness of
this program against all pests, particularly mites and aphids.

In summary, at least 2 more years of field research are
necessary before we will be in a position to make any firm recom-
mendations as to the cost-benefit value of alternate middle row
spray programs in Massachusetts. But the results of this first
year of research are encouraging.

*******************

All pesticides listed in this publication are registered and cleared
for suggested uses according to Federal registrations and State Laws
and regulations in effect on the date of this publication.

When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.

NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

WARNING: PESTICIDES ARE POISONOUS. READ AND FOLLOW ALL DIRECTIONS
AND SAFETY PRECAUTIONS ON LABELS. HANDLE CAREFULLY AND STORE IN
ORIGINAL LABELED CONTAINERS OUT OF REACH OF CHILDREN, PETS AND LIVE-
STOCK. DISPOSE OF EMPTY CONTAINERS RIGHT AWAY, IN A SAFE MANNER AND
PLACE. DO NOT CONTAMINATE FORAGE, STREAMS AND PONDS.

- 9 -

with every spray application, it would save 501 o£ the spray costs.
Richard Moore has done extensive research on this approach in
southern Connecticut, with very encouraging results. However, the
complex and the density of apple pests in southern Connecticut is
not the same as in Massachusetts. Hence, we needed to evaluate
this approach under our own conditions.

ed alternate with every middle row spray

block in each o£ 3 commercial apple orchards
d eastern Massachusetts. Each block was
one receiving the alternate row program on
ink through last cover; the other receiving

Each grower used an air blast sprayer at
ormal spray schedule, and used his own
s. All trees were full grown -- some on M-7
tandard. The centers of the trees were
1 blocks.

trea

in w

divi

each

the

4X.

sele

root

fair

In 19
tments
estern
ded in

spray
every

He fo
ction
stock;
ly wel

76 we
in a
, cent
to 2 p

date
row pr
llowed
of pes
other
1 open

compar
4-acre
ral an
lots
from p
ogram

his n
ticide
s on s

in al

To determine the extent
in each plot for monitoring c
flies (see Fruit Notes 41(1):
construction) . Vie caught the
trapping week for all orchard
codling moth = 6.0, apple mag
moth = 6.5, apple maggot = 1.
found that when codling moth
apple maggot abundance 1/trap
pests is very likely to occur
potentially damaging numbers
the alternate and every row p
of fruit injury caused by the
abundance of mites and aphids
60 leaves/tree on each of 6 t
3 weeks from May until harves

of insect p
odling moth
4 and 4 1(6)

following
s combined:
got = 1.9;
8. Researc
abundance e
/week, then

unless spr
of both the
lots. To d
se and othe

on leaves,
rees in eac
t.

est pressure, we

adults and appl

:7 for informati

average numbers/

alternate row
every row plot -
hers in other st
xceeds 2/trap/we
fruit injury fr
ay is applied,
se pests existed
etermine the act
r pests as well
we examined 60
h plot in each b

hung traps
e maggot
on on trap
trap/
plot --
- codling
ates have
ek and
om these
Thus,

in both
ual degree
as the
fruit and
lock every

The resul
of the fruit i
pared with 2.8
fruit in each
each plot by a
caused 0.2-0.4
most injury:
70% more abund
areas. No app
examined, but

ts (in the
n the ever
% in the a
plot was i
pple maggo
% injury i
2.0 -- 2.1
ant in the
le scab wa
some may h

Table below) show that an average of 2.71
y row plots was injured by insects com-
Iternate row plots. None of the sampled
njured by codling moth, and only 0.1% in
t. Plum curculio and European apple sawfly
n each plot whereas plant bugs caused the
%. Aphids and mites, however, were 60 to

alternate row plots than in the every row
s observed on any of the leaves or fruits
ave escaped our notice.

fruit infested

I leaves
infested

Treatment

Codling j'^ple Plum Apple Pl-m.i:
Moth Maggot Curculio Sawfly Bugs Other Total Aphids Mites

Alternate row 0.1 0.2 0.4 2.1 2.8 2.2 19.1

Every row

0.1

0.3

0.3 2.0

2.7 1.4

11.3

Establishment and Managennent of Compact Apple Trees

William J. Lord and Joseph Costante
University of Massachusetts

Part 4

Limb Positioning

Method of limb positioning. Limbs can be positioned
mechanically using spreaders or tie downs. Cultivars like
Delicious, Paulared and Macoun require limb positioning
more than Mcintosh and Cortland (Fig. 22).

Types of spreaders. A wide variety of spreaders are used:
spring-type clothespins, toothpicks, sharpened stiff wires or
welding rods, notched laths, or wooden sticks with a sharp-
ened nail In each end.

Spring-type clothespins or toothpicks are used on suc-
culent shoots. Clothespins are preferred because they can
be applied more quickly than toothpicks which need to be
sharpened and can be blown off the tree.

Wire or wooden spreaders are preferred on 1 -year-old
wood and older. Wire spreaders are generally no more than
10 to 12 Inches long, otherwise they may bend under pres-
sure. These can be purchased or made from 8-gage wire and
cut to various lengths. When making the wire spreaders, cut
them at a sharp angle with the point on each end on the
same side of the spreader. Spray painting the spreaders will
make them easier to find if dropped during placement or If
dislodged after placement.

. Softwood sticks 3/4 x 3/4 inche or 1 by 1 inch and cut

at various lengths are suggested for larger, stiffer branches.
Regular box nails (8 or 10 penny) are driven into ends of
the sticks and then the nail heads are cut at a sharp angle
forming a point. Additional sharpening with an emery
wheel will expedite placement and reduce limb damage.

Tie-downs can be used when branches have become too
long or stiff for spreaders. Materials for tying down the
limbs, such as baling twine, are cheaper than spreaders, but
the labor Involved in positioning the limbs is greater. When
the twine Is attached to a metal clip or wooden peg In the
soil, they may also cause Inconvenience.

Time of limb positioning. Spring-type clothespins or tooth-
picks are used when succulent shoots suitable for perma-
nent branches are 4 to 8 Inches long. The limbs will be-
come fixed in the spread position in about 2 weeks. The
spreading procedure should be repeated on other limbs with-
in 3 to 4 weeks using the clothespins attached in mid-June
and others If necessary. DO NOT spread the limbs too flat;
spread to a 45° to 60° angle from the central leader (a 90°

-—"■•"■■-•"'■f

y,*^"

.-..^l^ifi

m^m^'>sm

Fig. 22. Richared Delicious on MM 106 showing excessive
vegetative growth and the lack of limb positioning.

angle from the central leader would mean the limb is hori-
zontal to the ground). Spur-type trees need clothesplnnlng
more than the standard type cultivars.

Limb positioning with the wire or wood spreaders can
be done at any season of the year, but is best used during
the dormant season. The basic design of the tree is easily
determined during the dormant season and thus decisions
are easier to make concerning the need of spreading. Limbs
that are too crowded can be saved by spreading; perhaps
the greatest benefit of spreading Is the omission of pruning
(Fig. 23).

-»■*';

- —OS* >.--

Fig. 23. The best control of vegetative growth can be ob-
tained by combining mininnal pruning and limb
positioning.

Tree Nutrition

Fertilizer, either nitrogen (N) alone, a complete fertilizer,
or a fertilizer containing N and potassium (K2O) and minor
elements, should be applied 3 to 4 weeks prior to bloom
and at a rate of 1 /4 pound of ammonium nitrate or its equiv-
alent for each year of age.

Reduce or omit N on young, vigorous Mcintosh trees
when they start to bear fruit, if the trees appear very vigor-
ous, to avoid excessively large, poorly colored apples. With
this cultivar and all other cultivars, start participating in
the Leaf Analysis Program when the trees start to fruit in
order to determine the fertilizer requirements of the trees.
(Information concerning the Leaf Analysis Program and
specific details on orchard fertilization can be obtained from
your County Extension Service.)

Boron deficiency is more apt to be a problem with young
than older bearing trees. Therefore, boron should be applied
as a ground application or a foliar spray once the trees com-
mence to fruit if this element is not already present in suffi-
cient amounts in the fertilizer being applied annually. Exces-
sive N levels are particularly disastrous with bearing Mcintosh
trees and low Ca levels are a problem in all Massachusetts

apple orchards.

Once every 3 years, take soil samples and send them to
the West Experiment Station, University of Massachusetts,
Amherst, for determination of soil pH and lime requirements.
Directions fortakingsoil samples can be obtained from your
County Extension Service.

Weed Control

Chemicals (herbicides) are frequently used to control grasses
and broadleaf weeds under apple trees. Herbicides should
be used in such a manner that they provide early-season con-
trol of weeds, but not necessarily control for the entire
season. Regrowth of weeds in August and September can be
advantageous for the following reasons;

(1) The weed regrowth will help slow down growth of
vigorously growing trees and thereby lessen the
chance of winter injury.

(2) The weeds will provide some protection to the tree
roots against low temperature injury.

(3) They will reduce soil erosion.

The current recommendations for their use under apple
trees can be obtained from your County Extension Service.
In addition to chemical weed control, sand or gravel can be
applied around the base of trees to reduce weed growth and/
or an area in the vicinity of the trunk can be cleared of weeds
in the late fall.

Calibration of sprayer with tractor-mounted boom. The
sprayer can be calibrated by making a trial run over some
known area. (One acre contains 43,560 square feet. When
spraying a 4-foot swath, you must travel 10,890 feet to
treat an area equivalent to an acre.) The easy way to calibrate
the sprayer is to fill the tank completely or to some other
known level, spray 1/10 of an acre (1090 feet x 4 feet) and
then accurately measure how much water is required to refill
the tank to the previous level. Multiply the gallons used by
10 to get the gallonage per acre. If for example, the sprayer
delivered 60 gallons per acre and the herbicide is used at a
4-pound per acre rate, 4 pounds of the herbicide should be
added for every 60 gallons of water in the spray tank.

Calibration of granular herbicide applicator Granular appli-
cators must be calibrated with the herbicide actually being
applied. The best way to calibrate is to operate the applicator
over a known area such as 1/100 of an acre (436 sq. ft.).
You must catch dichlobenil* while operating over the known
area and weigh it. The usual way is to disconnect the spinner
and to collect the output from the applicator in a bag or
bucket. Weigh the dichlobenil very carefully because the
amount collected is quite small.

When using a hand-operated granular applicator, fill with
a known weight of dichlobenil*, operate the applicator over
a known area, and then weight the herbicide remaining in

*The only granular herbicide in common use.

Table 13. The number of trees that can be ground-sprayed with 100 gallons or 1 gallon of spray mixture
when applied at the rate of 100 gallons per acre and spraying around the tree trunk
the stated number of feet.

Distance sprayed

from middle of

the truni<

No. trees/I 00 gals.

Calculated Calculated

as a square as a circle

Approx. no. trees/gal.

Calculated Calculated

as a square as a circle

3 feet

4 feet

5 feet

6 feet

7 feet

1210
681
436
303
222

1539
868
555
385
283

12
7
4
3
2

15
9
6
4
3

Table 14. Ounces of dichlobenil required per tree when applying this herbicide by hand.

Area treated
around the base

Square area

6 ft. X 6 ft.

8 ft. X 8 ft.
10 ft. X 10 ft.
12 ft. X 12 ft.
14 ft. X 14 ft.

Circular area

6 ft. diameter

8 ft. diameter

10 ft. diameter

12 ft. diameter

14 ft. diameter

Ounces of dichlobenil G-4

At rate of 100 lb/A

1.3
2.4
3.7
5.3
7.2

1.0

1.8
2.9
4.2
5.7

At rate of 150 lb/A

2.0
3.5
5.5
7.9
10.8

1.6
2.8
4.3
6.2
8.5

the applicator.

Calibration of a handgun on a hydraulic sprayer or a com-
pressed air knapsack sprayer. When applying the herbicide
with a handgun and to a limited area around each tree,
calibration is relatively simple. First, determine how long it
takes to deliver one gallon of spray. Then choose from
Table 13 the plot size to be sprayed and note the number
of plots that a gallon will cover. Finally, determine the
length of time to spray one plot.

Example; (a) The hand gun delivered 1 gal. in 63
seconds.

(b) The distance sprayed from the middle of
the trunk will be 4 feet. When calculated
as a circle, 1 gal. will spray 9 areas of this
size.

(d) The data show that each plot should be

sprayed in 7 seconds.

Applying dichlobenil by hand. Some growers apply dichlo-
benil by hand on an individual tree basis. Table 14 above
indicates the ounces of dichlobenil to apply per tree based
on area to be treated. For example, if you plan to apply
dichlobenil at the rate of 100 pounds per acre and to treat a
circular area of 6-foot diameter under each tree, one ounce
of dichlobenil should be applied under each tree.

Mouse Control

Three general methods of bait application for mouse control
are available: hand trail baiting; mechanical trail baiting;
and broadcast baiting. Hand trail baiting, placement of zinc
phosphide-treated grain baits in natural mouse trails and
burrows, gives excellent control of both meadow and pine
mice but is slow and tedious especially when mice ^re not
abundant or surface signs of pine mice are obscure.

Treat 2 to 4 spots with teaspoonful quantities of bait

around the dripline of each tree. Pay particular attention to
low areas, rock outcrops, fence rows and orchard borders.
Bait should be placed near holes to underground burrows or
in active runways and under vegetation or artificial covers.
Apply at the rate of 2 to 3 pounds per acre. For pine mice,
bait should be applied to holes and burrows for best results.

Mechanical trail baiting. A tractor-drawn trail-building ma-
chine constructs artificial runs in which bait is distributed.
If properly done, 95% of meadow mice and 80% control of
pine mice can be expected by the trail builder method. A
trailbuilder should be operated so that the trail made by the
machine is just inside the drip line on both sides of the trees.
Apply at the rate of 2 to 3 pounds per acre. Check machine
accuracy for proper operation.

Broadcast application of bait by hand, cyclone seeder or
aircraft will provide control of meadow mice but control of
pine mice may not be adequate. Broadcast application by

tractor-drawn equipment is rapid but more bait is used than
with hand or mechanical trail baiting. Broadcast methods
give poor control when the ground cover is very dense,
including a heavy mat of leaves, as the bait fails to penetrate
into the mouse runways. Apply the zinc-phosphate-treated
baits at the rate of 6 to 10 pounds per acre.

Choose a period, immediately after harvest, of the least
human activity in the orchard and warm, clear weather for
applying the baits. This is the period when mice will be most
active and most apt to consume the applied baits. A thorough
and conscientious job is essential for good mouse control.

NOTE: Before applying any toxic baits, a permit must be
obtained for bait application from: Massachusetts Division
of Fisheries and Game, 100 Cambridge Street, Boston,
Massachusetts 02202. Pesticide regulations are always sub-
ject to change, therefore, always contact your local County
Extension Service for the latest information on rodenticide
and pesticide usage.

Cooperative Extension Service

University of Massachusetts

Amherst, Massachusetts

R. S. Whaley

Director

Cooperative Agricultural Extension Work

Acts of May 8 and June 30, 1914

Official Business

Penalty for Private Use, $300

POSTAGE AND FEES PAID
U. S. DEPARTMENT OF
AGRICULTURE
AGR 101

BULK THIRD CLASS MAIL PERMIT

Available to the public without regard to race, color or national origin.

FRUIT
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 42 (No. 4)
JULY-AUGUST 1977

TABLE OF CONTENTS

Considerations in Attempting to Improve the
Calcium Content of Apples

2,4-D for Problem Weeds in Strawberries

The Plum Curculio: An Introduction and
Summary of Preliminary Field
Observations, 1976

C02 Treatments for Mcintosh at the Begin-
ning of CA Storage

ese

CONSIDERATIONS IN ATTEMPTING TO IMPROVE ^
THE CALCIUM CONTENT OF APPLES

2
Heather A. Betts and William J. Bramlage

Department of Plant and Soil Sciences

Apples are subject to many diseases and physiological dis-
orders after harvest, all of which must be controlled to provide
a product acceptable to consumers. The mineral nutrient composi

tion of fruit at harvest greatly influences the occurrence of th

problems, and it is now widely recognized that calcium (Ca) content
is a key factor. Low Ca levels are implicated in development of
corking disorders such as bitter pit, cork spot, and Jonathan spot,
both before and after harvest. In addition, watercore, internal
breakdown, low temperature breakdown, lenticel breakdown, scald,
and rot may be intensified when fruit Ca levels are low. From
among these problems, bitter pit and internal breakdown have been
most extensively studied for their relationship to Ca nutrition.

Bitter pit has long been recognized as a Ca-def iciency prob-
lem. It is influenced by many environmental, orchard management,
and storage factors such as water stress, pruning, mineral balance,
and time of picking, and many of these influences may actually be
acting through modification of fruit Ca levels. Usually, the lar-
ger the fruit and the drier the growing season, the more bitter
pit is found. Some success in reducing bitter pit has been obtained
with calcium chloride (CaCl2) and calcium nitrate (CaCNOj)^ sprays
4 to 7 times during the growing season; CaCl2 is usually the pre-
ferred material since Ca(N02)2 adds nitrogen to the tree, which can
intensify a Ca deficiency. Sprays typically reduce the incidence
from 40% to 10% in 'Cox's Orange Pippin' apples in England. Since
mobility of Ca in the apple tree is very low, the Ca must be ap-
plied directly to the fruit for the treatment to be successful.
Ca dips after harvest have also been used to increase the Ca content
and decrease bitter pit occurrence during storage.

Internal breakdown usually occurs after harvest and is often
more prevalent in late-picked fruit. High relative humidity in
storage accentuates the disorder. It develops as extreme soften-
ing of the tissues, with brown discoloration that can become dark-
chocolate colored with time, and with the vacular bundles standing
out prominently as dark-brown strands. Recent studies show that
internal breakdown is greatly influenced by Ca nutrition. In Eng-
land, Perring determined that 'Cox's Orange Pippin' apples contain-
ing greater than 4.5 mg Ca/100 g fresh weight of flesh will usually

^This is a review article. Our current suggestions for increasing

Ca level in apple trees can be found in the May-June, 1977 issue

of Fruit Notes .

2
Present address: 200 Sullivan Street, Claremont N.H. 03743

- 2 -

be free from breakdown during storage, whereas at 3 mg/100 g fresh
weight the fruit is very likely to develop breakdown early in stor-
age. In Canada, Lidster, et al . determined that nearly this same
Ca level (4.5 mg/100 g) was required for maximum protection of
•Spartan* apples from breakdown in storage. Spraying and dipping
apples with Ca solutions before storage have frequently been effec-
tive in reducing internal breakdown. One spray program raised the
Ca level of the fruit from 3.7 to 5.4 mg Ca/100 g of fruit flesh,
and correspondingly reduced the occurrence of breakdown in storage
from 16% in the controls to 0% in the treated fruits. In Massachu-
setts, we have consistently found in recent years that in a given
situation, greatest incidence of internal breakdown occurs in the
apples with the lowest Ca content.

There is, therefore, strong reason for a fruit grower who is
having difficulty maintaining fruit quality during storage, to be
concerned about Ca nutrition of the fruit. Unfortunately, it is
not easy to substantially increase Ca levels of apples. Ca is one
of the most abundant minerals in most soils, yet fruit frequently
contain inadequate amounts of this mineral. Apple tree roots do
not readily take up Ca from the soil, and what they can take up is
influenced by numerous soil conditions. Thus, lime and Ca fertil-
izers do not quickly or markedly increase Ca levels in apples.

Leaves seldom show Ca deficiency symptoms even though fruit
may be severely deficient. What Ca is absorbed from the soil is
transported very slowly within the tree, and what is transported
is apparently directly by water use in the tree. Movement is
largely within the xylem (the water transporting system) . Early
in the season, small apples are using large amounts of water, and
relatively large amounts of Ca move to the fruit with this water.
By mid-season, however, apples are using much less water and are
also serving as a large depository for sugars and other organic
nutrients coming from the leaves. These nutrients are moving
through the phloem (the food transporting system) , in which Ca is
relatively immobile. Therefore, little Ca is transported to the
fruit late in the season, since the fruit are being supplied large-
ly by the phloem system. As a result, 901 of the apple's Ca may
move in during the first 6 weeks after full bloom. When water
stress occurs in the apple tree, water may be drawn from the fruit
to the leaves, and simultaneously Ca may be withdrawn from the
fruit. In this way, water stress may create or intensify Ca defi-
ciency in the fruit.

The average Ca level in the fruit is considerably lower than
that in the rest of the tree. Within the apple fruit itself there
are large differences in the concentration of Ca. In the cortex
(outer flesh) of mature apples, Ca concentration declines steadily
from the stem end to the calyx (blossom) end, which is probably
why bitter pit and internal breakdown usually begin to develop (and
develop most intensively) at the calyx end of the apple. The apple

- 3

peel has al-out 3 times more Ca in it than has the flesh. Because
of this uneven distribution, Ca concentration is sometimes extreme-
ly low in the fruit tissues most sensitive to physiological disor-
ders.

An understanding of these characteristics of Ca nutrition of
apples is important in designing a program to improve fruit Ca lev-
els. Much work has been done worldwide to increase Ca levels in
apples. Soil treatments have been of little measureable benefit.
Tree sprays of Ca salts such as CaCl2 and Ca(N07)2 have given some
success in increasing Ca levels and reducing disorders. Their ef-
fectiveness usually increases with concentration of the salts in
the spray mix and with the frequency of spraying, A common cause
for unsatisfactory results is poor spray coverage; because of the
low mobility of Ca to fruit within the tree, thorough and uniform
coverage is essential. This problem may be intensified by appli-
cation of Ca in concentrate sprays.

Postharvest dips have the advantage of being able to complete-
ly cover the fruit with solution. In England, researchers in one
trial got similar control of bitter pit with a postharvest immer-
sion for 1 minute in 0.05 M Ca(N03)2 as with 4 summer sprays of the
same solution. However, CaCl^ again is considered to be a more
effective salt for dips than CaCNO)-, at least in part because
CafNOj)^ will support bacterial growth and leave an undesirable
residue on fruit after storage. Other substances have been added
to the dipping solution in order to increase the penetration of
Ca into the fruit, with varying and often conflicting results.
The most striking effects have been obtained by adding "thickeners"
to the dipping solution. Mason and his colleagues in Canada have
used arrowroot flour and the commercial thickener keltrol with
great success. With 'Mcintosh,' dips in 41 CaCl2 plus keltrol al-
most tripled flesh Ca during storage, and significantly reduced
the softening rate of the fruit during and following storage. These
thickeners apparently cause much more Ca to adhere to the surface
of the apple, from which it can be absorbed into the flesh later
during storage.

Injury can result from excessively heavy treatments to in-
crease Ca levels. Tree sprays can severely injure leaves, especi-
ally early in the season or in hot weather. Postharvest dips can
cause injury to the surface of the fruits, usually appearing as a
burn or as black spots at the calyx end of the fruits. In most
cases, fruit inury is not serious, but in a report from New Zea-
land 23% of 'Cox's Orange Pippin' were injured by a 2.5% CaCl2 dip.

As we learn more about the effects of mineral deficiencies on
storage life and quality retention in fruit, it becomes increasingly
important to develop strategies to overcome the deficiencies. Solu-
tions will not be simple. Following a comprehensive study of fac-
tors related to storage breakdown of 'Spartan' apples in British

- 4

Columbia, Canada, Lidster, et a1 . concluded that: "The fruit and
orchard profile for expected minimum breakdown incidence would be
as follows: (1) high Ca content in apple flesh (minimum of 42.4
ppm fresh weight): (2) apple K (potassium) and B (boron) content
to be less than 883 and 2.9 ppm, respectively; (3) small apple di-
ameters [optimum diameter, 5.8 cm (approximately 2.30 inches)];
(4) low apple soluble solids (below 11.9%); (5) low to moderate
tree vigor [terminal growth less than 46 cm (approximately 18
inches)]." These 5 factors accounted for 75% of the variation in
breakdown among different samples, but that still left 25% to be
accounted for by other factors.

It will be necessary for the grower to understand the complex
ity of the Ca problem in apples if the problem is to be success-
fully overcome. We have attempted in this brief review to outline
the key features of the Ca problem, so that as growers look ahead
to the coming season they can better understand why specific ac-
tions or conditions can or cannot be expected to influence the Ca
levels of their fruit, and thereby influence the storage life and
quality of next year's crop.

***************

2,4-D FOR PROBLEM WEEDS IN STRAWBERRIES

Dominic A. Marini
Southeast Regional Fruit and Vegetable Specialist

Broadleaf perennial weeds, such as dandelions, can be a seri-
ous problem when carrying over strawberry beds for 2 or more sea-
sons. The commonly used strawberry herbicides do not control these
perennial weeds and hand weeding of deep-rooted perennials is vir-
tually impossible.

on ol
leaf
f rui t
gle a
V a t i
pi ant
estab
to fr
in 2 5
appl i
growt

Dow Fo
d or e
weeds .
s , we
p p 1 i c a
ng the
ings.
1 i s h e d
u i t b u
to 50
ed dur
h.

rmula 40*

stabl i shed

In the 1

are sugges

t i n of t h

harvested

Furthermo

beds are

ds. The r

gallons o

ing warm w

formulation of 2,4-D is now registered for use

strawberry beds for the control of many broad-
977 chemical weed control chart for small
ting for the control of broadleaf weeds, a sin-
is herbicide applied right after mowing or ren-

strawberry bed. It should not be used on new
re, spring or fall applications of 2,4-D to
not recommended because of the possible injury
ecommended rate is 1 to 1-1/2 quarts per acre
f water. For best results, 2,4-D should be
eather when weeds are young and making rapid

Since many crops and ornamental plants are sensitive to only
the slightest trace of 2,4-D, it should be applied under calm con

*Trade name

ditions when there is no possibility of drift onto nearby plants.
Tomatoes, grapes, and roses are particularly susceptible to injury.
Applying a dilute spray using nozzles that deliver large, coarse
droplets and low pressure reduces the possiblity of drift.

Clean the sprayer thoroughly after using it to apply 2,4-D be-
cause trace amounts of this herbicide can injure sensitive crops.
In fact, it would be best not to use the same sprayer for other
crops. If this is unavoidable, rinse thoroughly with clean water
and then fill the tank with a solution of 1 part household ammonia
to 99 parts water and allow it to remain for 24 hours. Then pump
some of this solution through the system, drain, and rinse again.
A quicker method is to fill the tank 1/3 full of water and add 1/4
pound of activated charcoal and 2 to 4 ounces of laundry detergent
for each 10 gallons. Agitate the mixture and swirl it around in
the tank for at least 2 minutes so that it reaches all parts of the
tank. Pump some through the system, drain, and rinse with clean
water.

Where broadleaf perennial weeds are a problem in established
strawberry beds, 2,4-D can be useful for their control, but it
must be used with extreme caution because of the possibility of in-
jury from drift onto nearby sensitive plants and the need for re-
moving every trace of it from application equipment.

***************

THE PLUM CURCULIO: AN INTRODUCTION AND SUMMARY OF PRELIMINARY

FIELD OBSERVATIONS, 1976

Karen I. Hauschild and Ronald J. Prokopy
Department of Entomology

The plum curculio is one of the most serious pests of apples
in Massachusetts. It is a native species, originally found on
wild plums, crabapples, and hawthorn; however, with the past cen-
tury, it has adapted to most tree fruits as they have become in-
troduced from Europe. Here we outline the life history as known
from the literature, and discuss some of the results of our first
year (1976) of research studies.

Dr. Whitcomb, of the Waltham Experiment Station, conducted
an extensive study of the biology of the plum curculio in Massa-
chusetts in the 1920' s. He found that in some years a few adult
curculios arrive on apple trees as early as the pink stage. Ac-
cording to his study, feeding punctures can be found from the
last week in May, while oviposition (egg-laying) occurs from late
May to mid-July. Mating, he found, occurs prior to, or during the

- 6 -

time when the adults arrive on the trees. Eggs hatch in about a
week. Larvae then tunnel into, and feed on, the developing fruits
for the next two to three weeks. Most of the larval-infested
fruits drop to the ground, and there the larvae leave the fruits
to pupate in the soil. Adult curculios emerge from the soil approx-
imately one month after that. These emerging adults feed on late
apple varieties or leaves and then overwinter, unmated, in or near
orchards. There is only one generation of curculios in Massachusetts.

Damage caused by the plum curculio is of several different
types. Early in the season, curculios feed on and lay eggs in
young fruits. These fruits are then scarred with surface wounds.
Small round holes are the result of feeding punctures, while cres-
cent-shaped yellowish scabs are the result of egg-laying activities.
The most important injury is larval tunneling inside the fruits and
the correspondent fruit drop. Feeding scars of the adults in the
fall and adult feeding damage on blossoms in the spring are other
types of injury.

Controlling this pest has been a frequently difficult as well
as expensive task, even with modern insecticide sprays. Research-
ers in other states are working on alternatives to chemical con-
trol of the plum curculio, but to date no practical means of con-
trol other than insecticides have been developed. A reduction in
the number of chemical sprays against the curculio would not only
save growers' money, but in addition would postpone the onset of
possible pesticide resistance, and decrease pesticide contamination
in the environment. Beneficial insects such as pollinators, preda-
tors, and parasites would also undoubtedly benefit from reduced
numbers of insecticide sprays.

One of the purposes of our plum curculio project here in the
Department of Entomology is to study the activities of the adults
to determine whether there is any behavioral trait which could be
used in the development of a curculio trap. Although some aspects
of the biology and life cycle of the curculio are reasonably well
understood, there is little information on its behavior. A trap-
ping device such as is used for apple maggot or lepidopterous
pests (for example, the codling moth) would (coupled with informa-
tion on how many curculios an orchard could tolerate without affect-
ing crop quality or yield) aid the grower in determining whether
and when he should use insecticides against the curculio. It also
is possible that such a trapping device could be used as a direct
control measure -- that is, the trap itself could be effective in
controlling adult curculios, especially where only small popula-
tions were present.

The major study that was conducted last summer involved spend-
ing many hours observing the behavior of adult curculios on apple
and plum trees located on Orchard Hill on the UMass campus. The
purpose of this study was to obtain some understanding of the cur-

7 -

culios' behavior. Observations were made at varying time intervals
from 8:00 A.M. to 9:00 P.M. on warm, sunny days. Once we had lo-
cated a curculio we watched that insect until it moved out of sight,

From these observations, we found that the main activities
of adult curculios were:

1. Exploration - moving about a tree in search of food,

ovipositional or resting sites.

2. Defense or camouflage behavior (These insects are very
sensitive to noises or other disturbances.)

3. Resting

4. Feeding

5. Ovipositing (egg-laying)

An adult curculio appears to have little recognition of places
it or other curculios had previously visited, as individuals spent
considerable time re-exploring the same areas. Curculios were
rarely observed flying, spending most of their exploratory time
crawling. It appeared that they were able to distinguish fruits
from twigs and foliage only upon direct contact, and not by dis-
tance vision or smell. In terms of egg laying behavior, females
spent several moments "drumming" their antennae and tarsi (feet)
on the fruit before they would attempt to lay eggs.

These observations would suggest that curculio behavior is
rather complex, and for this reason it will take considerable time
to discover what methods curculios use to find their host trees,
food and mates. It appears that this insect has comparatively
little dependence on vision. For this reason, we doubt that a
trap employing only visual stimuli would be very effective. Also,
since within-tree flight appears to be of minor importance, traps
aiming to capture curculios flying within trees would likewise
probably not be very effective. Traps based on insect flight to
visual stimuli are relatively easy and quick to develop and use,
and we have indeed experienced some success with such traps for
tarnished plant bug, sawfly and apple maggot.

We are closer to an understanding of plum curculio behavior
than we were a year ago. However, many further long term studies
on the behavior of adult plum curculios will have to be carried
out to uncover some behavioral trait which would lend itself to
an effective, efficient and reliable trapping device.

8 -

CO2 TREATMENTS FOR 'McINTOSH* AT THE
BEGINNING OF CA STORAGE

William J. Bramlage
Department of Plant and Soil Sciences

Perhaps you have read about the CO2 treatments that are being
used in Washington to slow dovm softening of 'Golden Delicious'
apples in CA storage. This procedure has gotten a lot of publi-
city and is working very well in commercial storages in that state.
If you have read any of these reports, you have surely wondered if
the same treatment will work on 'Mcintosh'. So have we, and in
earlier Fruit Notes articles (Sept-Oct, 1973 and Sept-Oct, 1975) we
reported results of our preliminary studies with this procedure.
In 1975, we also reported that a large-scale test was to be conduc-
ted to determine the feasibility of this "COo pretreatment" of
'Mcintosh*. This test has now been completed and its findings can
be reported.

The 'Golden Delicious* treatment simply consists of raising
the CO2 level in the storage to 15% during the first 8 to 10 days
of CA storage, then scrubbing it down to the normal CO2 level for
CA storage. It results in much slower softening of the apples and
allows the growers to market crisp fruit into late spring and early
summer. In preliminary tests with 'Mcintosh', both in Massachusetts
and in other areas where this variety is important, the trials in-
dicated that softening of 'Mcintosh' could also be slowed down by
CO2 pretreatment, but that there was considerable danger of COo in-
jury from the treatment. To evaluate as broadly as possible the
potential benefit and potential danger from such a treatment, a co-
operative study was made at 5 locations where 'Mcintosh' is an im-
portant variety: Massachusetts, New York, Michigan, Ontario, and
British Columbia.

At all 5 locations, a treatment that had appeared in prelim-
inary tests to be about optimum for 'Mcintosh' was tested. It con-
sisted of liarvesting the apples at peak time for CA storage, quickly
cooling them to 38°F, and as quickly as possible sealing them in
CA where COo was brought to 12%. This 12% CO2 atmosphere was main-
tained for 2 weeks and then the apples were put under normal CA
conditions of 5% COo and 3% O2. The samples were kept in CA for up
to 8 months before Being compared with other CA samples that had
not received the 12% CO2 pretreatment.

Besides conducting this test of what was believed to be about
the best treatment for 'Mcintosh* , each participant tested the
effects of 1 or more of the following factors that might influence
response to the CO2 treatment: harvest date; delaying treatment
after harvest; slow cooling during treatment; temperature, humid-
ity, and O2 level during treatment; increased CO2 concentration;
and, increased length of the CO2 treatment.

- 9 -

The results from these tests clearly demonstrated that the
CO2 pretreatment can delay softening of 'Mcintosh' in CA storage.
At every location, treating them with 121 CO2 for 2 weeks produced
apples that were 1 to 2 lbs firmer than untreated CA samples after
4 to 6 months in storage. However, the effect gradually wore off;
after a week at room temperature these differences had largely dis-
appeared, and after 7 to 8 months of storage even the fruit right
cut of storage showed only small differences. Nevertheless,
these differences would be well worth the treatment if no problems
arose from the treatment.

But there are problems! Both external COo injury (a scald-
like burn) and internal CO2 injury (a form of internal breakdown)
developed. The extent of these injuries was variable among loca-
tions; external injury occurred everywhere except in Michigan, and
internal injury was distinct only in British Columbia. However,
the problems were sometimes overwhelming; in British Columbia, 431
of the fruit had external injury, and 53% had internal injury, and
in New York 30 to 351 of the apples had external injury. In Massa-
chusetts, we've found the extent of injury to vary from year to
year, sometimes not occurring at all and in other years occurring
to a serious extent. We also find different samples varying great-
ly in the amount of injury that they develop from the same treat-
ment. Just as it was obvious in these tests that the CO2 treat-
ment can delay softening of 'Mcintosh', it was also obvious that
the treatment has the potential of causing very serious damage to
the stored apples.

What about other factors that might influence results? We
found that increasing the CO2 level from 12% up to 15% resulted
in a bit more fruit firmness after storage, and that increasing
treatment time from 2 weeks to as much as 6 weeks did likewise.
However, both of these modifications increased the amount of CO2
injury as well as increasing firmness of the apples. Harvesting
the fruit 1 week earlier than peak time increased treatment bene-
fit, but again it also increased the amount of injury. Harvesting
1 week later than peak time reduced benefit from the treatment.
Treating the apples at 32°F rather than at 38° reduced both bene-
fit and injury. In tests in New York, treatment was begun when
the apples were still warm (55°) and they were cooled to 38° dur-
ing the 2-week treatment; the CO2 treatment was of no value in de-
laying softening of these warm fruit. In Michigan, apples were
kept at 70°F for a week, or at 32° for 1 or 2 weeks, before they
were treated; any delay reduced treatment benefit, and 1 week at
70° eliminated any benefit. The O2 level and the humidity in the
storage during the CO2 treatment had no effect on the delay in
softening brought about by the CO2 pretreatment.

It was rather clear from the results of these tests that rais-
ing the CO2 level to 12% for 2 weeks at the beginning of CA storage
has no magic effect on the apples; it simply slows down their rate
of ripening even more than CA alone does. Anything that increases

- 10 -

ripeness (late harvest, slow cooling, delayed treatment, etc.) be-
fore treatment takes away from the benefit obtained from the treat-
ment. Benefit from treatment is increased when less ripe apples
are treated. However, factors that increased the ability of the
treatment to delay ripening and softening also increased their sus-
ceptibility to CO2 injury. The only exception to this was storage
humidity. We found that by not humidifying the storage until after
the COt treatment, injury was reduced but firmness was not. Later
tests m British Columbia support this finding. However, it re-
mains to be determined if this technique is practical, and if it
produces new problems.

After examining the results of these tests, it was the unani-
mous conclusion of those who participated in them that for 'Mcin-
tosh', the possible benefits to be gained from the CO2 pretreat-
ment did not outweigh the possible losses that might result from
CO2 injuries. Unfortunately, 'Mcintosh' seems to be more sensi-
tive to CO2 than are 'Golden Delicious' in Washington. Unless a
way can be found to reduce the risk of injury without reducing the
delay of softening, CO2 pretreatment of 'Mcintosh' cannot be recom-
mended for commercial practice.

***************

All pesticides listed in this publication are registered and cleared
for suggested uses according to Federal registrations and State Laws
and regulations in effect on the date of this publication.

When trade names are used for identification, no product endorsement;
is implied, nor is discrimination intended against similar materials,

NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whalev
Director
Cooperative Agricultural Extension Worl<
Acts of May 8 and June 30, 1914

Official Business

Penalty for Private Use, $300.

POSTAGE AND FEES PAID
U.S. DEPARTMENT OF
AGRICULTURE
AGR 101

BULK THIRD CLASS MAIL PERMIT

FRUITpr
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol 42 (No. 5)
SEPTEMBER/OCTOBER 1977

TABLE OF CONTENTS

The National Controlled Atmosphere Research
Conference

Monitoring Traps for Blueberry Maggot Flies

Pomological Paragraph

Ethephon' s use to promote early-ripening of
Mcintosh

Some Details to Consider When Harvesting and
Storing Apples

THE NATIONAL CONTROLLED ATMOSPHERE RESEARCH CONFERENCE

William J. Bramlage
Department o£ Plant and Soil Sciences

On April 5-7, 1977, a National Controlled Atmosphere Research
Conference was held at Michigan State University, bringing together
nearly 100 persons with professional interests in controlled atmos-
phere storage of various commodities. The last such conference
was held in 1969, and the main objective of this meeting was to re-
view the changes that have occurred since then. The focal points
of the meeting were the consideration of new techniques and new
problems, and an update on our knowledge of the responses of differ-
ent commodities to CA. The full proceedings of the Conference will
be available soon, but in this article I will touch on the points
that may be of most interest to our readers.

Storage construction . Probably the biggest concern today with
storage construction, is the problem of how to fireproof polyure-
thane satisfactorily. Flame retardants have been of limited value,
and some of the approaches that are being taken either are not prac-
tical in a storage or are of unproven durability. Several speakers
concluded that the most reliable way to fireproof urethane is to
cover it with one-half inch of cement mortar. Mr. Keith Clarke,
of Vineland, Ontario suggested that at a minimum, a urethane-sealed
storage should be dealt with as a highly flammable structure:
Treat it as a farmer does his haymow, he suggested. Some storages
have burned because their owners were using them as workshops!

Construction methods were discussed by Mr. D.L. Hunter of
Yakima, Washington. Of considerable interest today is how to con-
serve energy in the storage. He pointed out that large rooms (e.g.,
40,000 bu capacity) are most efficient, as are large capacity re-
frigeration units. However, large units give you less air move-
ment per unit. One common mistake in storage is to put fans in
front of cooling coils. This arrangement adds the heat from the
fan to the room air.

Mr. Hunter also described the use of a rubber gas seal that
can be sprayed on behind the insulation. Rubber gas seals have
been very successful where they have been applied carefully. The
first storage to use this material was built in 1969 in Kelowna,
British Columbia; this storage has been expanded three times since
then, always with th-e rubber vapor barrier, and over a million
bushels of apples are now stored in it. The operator of this stor-
age was at the Conference and verified the successful use of this
gas seal.

- 2 -

Storage operation . Since a storage operator can choose from
a long list of scrubbbing techniques, a common question is: Which
is best? Lime boxes are not used in many areas, partly because
they are considered to be a nuisance, but they are very effective.
We have been urging growers not to put lime in the storage because
it keeps the CO2 level so low that the CO2 is not providing its
maximum effect m delaying ripening of the fruit in storage. How-
ever, tests in New York showed no adverse effect on the fruit from
having lime in the room. This technique of course provides protec-
tion from CO^ injury, but you must consider that it displaces some
fruit. Dr. G.D. Blanpied, of Cornell University, compared data on
costs for various scrubbing systems. Water scrubbers are very effec-
tive, but corrosion of bearings, motors, and switches from the brine
raises operating costs. This can be avoided by having a separate
water scrubbing system, which costs more to install but which saves
money in the long run. Surprisingly, Dr. Blanpied' s analyses indi-
cated that in the long run the least expensive scrubbing system may
be the commercial scrubbing devices that use charcoal as CO2 adsorb-
ant. While they are expensive to purchase and install, their oper-
ating expenses are very small and they have a long operating "life."

Another operation technique of considerable interest is the
possible use of high-C02 treatments at the beginning of CA storage.
This question will be considered in a separate article.

Commodity responses to CA storage . In the U.S., about 38% of
the apple crop is stored in CA. In the Northeast, the percentage
is much higher than this and has probably reached its peak, but

in the Southeast and Midwest the "growth areas" for CA storage

of apples only a small percentage of the crop is stored in CA.

The question we can now ask is, what about storing commodities
other than apples? In the West, many pears are stored in CA, but
in the East a greater susceptibility to CO^ injury almost rules out
CA storage of pears. Progress is being maae in developing techni-
ques for CA storage of peaches and nectarines, but there is no com-
mercial application yet. Sweet cherries may be stored in CA, but
there is little evidence that it is better than storage in air if
good temperature control is maintained (29-30°F is optimum). Avo-
cados are being successfully stored commercially in Florida, but
the potential for development is limited. Much effort has gone
into tests for CA storage of citrus, but without success.

Vegetables are extensively transported in CA-equipped trucks
and vans. One of these systems ("Transfresh") ships 5 million
pounds of foodstuffs per week, mostly by truck, and another ("Sea-
land") is involved primarily in ocean transport. However, these
are short-term treatments aimed specifically at transportation
problems. Long-term storage of vegetables in CA has not proven fea-
sible. There is often interest in storing tomatoes in CA, but this
is very dangerous because tomatoes can easily be injured by a stor-

3 -

age environment. Root crops (carrots, beets, potatoes, etc.) have
been extensively tested and simply are not suited to CA storage.
Frequent mention is made of CA storage for flowers, but laboratory
successes are very difficult to put into commercial practice, due
in part to the vast number of flower species, varieties, and grow-
ing conditions that can all influence storage responses.

On the national scene CA storage is moving into some new areas.
Some excellent results have been obtained from nut and grain tests
with CA, and commercial storage is now practiced. The object here
is mainly to control insects. Also, use of CA during transit of
meat is growing rapidly, and 401 of the "Transfresh" shipments are
with meat. In this case, the object is mainly to control bacteria
growth and discoloration of the meat.

To the Northeast storage operator, however, it is evident that
CA storage today is still an apple industry.

Hypobaric storage . During the past 10 years, a new concept
in storage has emerged. It is called "hypobaric storage", "low
pressure storage," or simply "LPS." This approach involves storing
produce under a strong vacuum, which removes gases (like the ripen-
ing ethylene) from the produce almost as fast as they are formed.
It also greatly reduces the amount of oxygen they are receiving,
and removes COo as fast as it forms. This type of storage has pro-
duced some remarkable results with storage of many commodities, in-
cluding apples and pears. 'Mcintosh' apples in March are said to
taste like they were just harvested.

There are many engineering problems involved with applying
the technique. It would require whole new approaches to storage
construction. Tests with this new storage method have now been
made on small scales in a number of different places, and results
were critically evaluated at this Conference. It seems clear that
LPS can work, and work well, on a number of crops. Grumman Allied
Industries, Inc. (basically, an aerospace industry) is developing
40-foot long units for transporting produce in LPS, but they are
still experiencing technical problems. Even when it becomes tech-
nically feasible to commercially build and operate LPS systems,
they will be expensive. How economically competitive LPS will be
with CA remains to be determined. The recurring theme of reports
given on the use of LPS was that the spectacular effects first re-
ported for this system led to expectations that were too great.
More realistic assessments now state cautious optimism that LPS
will take its place in post-harvest horticulture, but that CA and
other systems now being used have not been made obsolete.

Summary. This 1977 National CA Research Conference brought
together a great deal of knowledge, and some controversy, about

- 4 -

the use of CA in today's horticultural industry. Proceedings of
this Conference should be of interest and value to everyone in-
volved in CA storage. We will inform you in Fruit Notes how to ob-
tain copies when they are published.

***************

MONITORING TRAPS FOR BLUEBERRY MAGGOT FLIES

Ronald J. Prokopy and William M. Coli
Department of Entomology

The blueberry maggot, Rhagoletis mendax, is generally consid-
ered the most important insect pest of commercially grown highbush
blueberries in the eastern and mid-western United States. The
adults look identical to apple maggot adults, but are a different
species. They emerge from overwintering cocoons about the time
earliest-ripening berries are turning reddish blue. They feed for
about 10 days-principally on insect honeydew on foliage, mate, and
then commence laying eggs into the berries. The eggs hatch in
about 4 days, and the larvae (maggots) feed for about 2 weeks on
the flesh of the berry, causing it to rot. Infested berries may
look in fine condition on the outside but be soft and mushy inside.
When no measures are taken to prevent injury, 501 or more of ripe
berries may be maggot infested.

The standard method of controlling the blueberry maggot is
application of 3-5 insecticide treatments against the adults. At
present, the treatment schedule followed by most growers is a type
designed to prevent any possible maggot injury, irrespective of
whether or not maggot flies are actually present. If there were
a method available for accurately assessing fly abundance in the
plantation and eventually relating fly density to level of larval
infestation, then the decision as to whether or not insecticide
should be applied could be made on a firm cost-benefit basis. Un-
necessary and uneconomical sprays could be eliminated, resulting
in (a) monetary savings to the grower, (b) less pesticide residue
on and in the fruit and in the environment, (c) less selective
pressure for rapid development of maggot fly resistance to insecti-
cides, and (d) greater opportunity for natural enemy buildup. Un-
til now, no effective method for assessing blueberry maggot fly
abundance has been available.

In 1976 and 1977, we studied the reactions of blueberry mag-
got flies to visual and combined visual-odor stimuli. When we
tested their responses to 6 x 8 inch painted cardboard rectangles

Graduate Student in Department of Plant and Soil Sciences

- 5 -

hung from highbush blueberry branches, we found that the flies
were more attracted to yellow enamel ones than to enamel green,
blue, orange, red, white, gray, black, aluminum foil, or clear
Plexiglas ones. We then found that the maggot flies were even more
attracted to daylight fluorescent yellow rectangles than to enamel
yellow ones. These color responses of blueberry maggot flies were
virtually identical to the color responses of apple maggot flies
in earlier tests (see Sept. -Oct., 1976 issue of Fruit Notes ) . We
believe that the reason the flies are so attracted to bright yellow
color is because they perceive yellow as if it were super-bright or
super- intense foliage on which to find food.

In another test, we hung 1.3 and 3- inch diameter red spheres
and found the blueberry maggot flies highly attracted to both, but
especially to the 3-inch ones. This is very similar to our findings
on apple fly response to red spheres (see Nov. -Dec, 1976 issue of
Fruit Notes ) . We believe that the reason the flies are so attrac-
ted to 3-inch red spheres is because they perceive such spheres as
if they were super-large blueberries on which to find mates or lay
eggs.

We then coated 6 of the 6x8 inch daylight fluorescent yel-
low rectangles and 6 of the 3-inch red spheres with Bird Tangle-
foot (a clear sticky substance that captures and holds arriving
flies) and hung them from highbush blueberry branches in a planta-
tion in Munson, Mass. from July 13 to August 11. We caught a total
of 1547 blueberry maggot flies on the rectangles and 3309 on the
spheres. When ammonium acetate crystals (an odoriferous bait attrac-
ting food-seeking flies) was added to a second set of 6 yellow rec-
tangles, 2206 maggot flies were captured. This was more than on
the unbaited yellow rectangles, but fewer than on the unbaited
spheres .

These findings indicate the sticky-coated daylight fluorescent
yellow rectangles and 3-inch red spheres are effective traps for
capturing large numbers of blueberry maggot flies. Hence, they can
be profitably employed to monitor maggot fly population levels and
activities in commercial plantings. Their use will aid in better
timing of maggot fly sprays, and avoidance of unnecessary applica-
tions when no maggot flies are present.

Proper positioning of the traps is critical to their fly-cap-
turing effectiveness. They must be hung so that the flies can
clearly see them. Therefore, all foliage, twigs, and berries within
8-12 inches of all sides of each trap should be removed. But be-
yond this distance, there should be as much fruit and foliage as pos-
sible (especially below and to the sides) to attract flies into the
general area. Although we have not yet established any firm rela-
tionship between maggot fly trap captures and fruit infestation
levels, we would suggest that capture of 5 flies per trap per week
may warrant insecticide treatment on highbush berries grown for

- 6 -

the fresh market. At least 1 trap per acre should be employed.
Berries grown for processing may require treatment when fewer than
5 flies per trap per week are captured.

Where can the traps be purchased? Sticky-coated, ammonium-
acetate-baited fluorescent yellow rectangles can be bought from
Zoecon Corporation, 975 California Avenue, Palo Alto, California
94304, at a cost of about $1.00 each. Each rectangle will prob-
ably need replacing with a new one at mid-season owing to accumu-
lation of large numbers of other large insects which may cover up
and obscure the smaller maggot flies on the trap. Sticky-coated
3-inch red spheres, likewise baited with ammonium acetate, may be
purchased for about $1.00 each from New England Insect Traps, Box
301, North Amherst, Mass. 01059. Such spheres are quite selective,
capturing relatively few other insects. They will last many sea-
sons and require coating with Tanglefoot only at the beginning of
the season and perhaps again after a series of heavy rains. Which-
ever type of trap you choose to use, it should, over the long term,
pay you dividends in reduced spray costs for this insect.

***************

POMOLOGICAL PARAGRAPH

Ethephon's use to promote early-ripening of Mcintosh. Our sugges-
tions for ethephon use on Mcintosh are based on 3 time periods for

sale of ethephon- treated fruit prior to normal harvest time

(Labor Day or shortly after), during normal harvest, and after sev-
eral months of storage. To have well-colored Mcintosh by Labor Day,
we suggest applying ethephon at 2/3 to 1 pint plus 20 ppm 2,4,5-TP
8 to 12 days prior to anticipated harvest. These suggestions have
worked well at our Horticultural Research Center. In 1975, we ap-
plied 1 pint of ethephon plus 20 ppm 2,4,5-TP with an airblast
sprayer on August 27 and had adequate color for harvesting by Sep-
tember 2. In 1976, we applied the same mixture on August 16, and
harvested the fruit August 26.

***************

SOME DETAILS TO CONSIDER WHEN HARVESTING
AND STORING APPLES

F.W. Southwick
Department of Plant and Soil Sciences

Pre-Harvest Conditions

Harvest

Abnormally high temperatures during the few weeks prior
to harvest tend to make most apple varieties more suscep-
tible to storage scald in both regular and CA storage.

Preharvest drop tends to be most severe when: (a) hot
weather prevails; (b) trees have a large crop; (c) foli-
age is damaged by drought, frost, insects and diseases;
(d) trees are deficient in boron, magnesium and potassium;
and (e) trees have a high nitrogen level.

The preharvest drop control materials NAA and 2,4,5-TP
are effective when applied before damage to the foliage
occurs - not afterward.

Apples continue to increase in size as long as they re-
main attached to the tree. A significant increase in
total bushels harvested is possible by delaying harvest
,.,u^^^,,^^ ^..^u r.^^.A — ^,,4-1-^ your marketing strategy. Of

whenever such action suits

course, preharvest drop control, fruit maturity and sus-
ceptibility to various fruit disorders must be kept in
mind.

There is no single optimum maturity date for a variety
during the picking season for fruit to be sold through-
out a 9-month marketing period. For example, the desired
maturity of apples for immediate post-harvest sale may
be much more advanced than for regular or CA storage.

Mcintosh for CA storage shou
from 15-17 pounds and posses
color. Such fruit will be 1
scald and be in a firmer, ju
May than more mature, later
Mcintosh placed in regular s
ruary) will develop less sea
mature at later picking date
the less mature fruit is inv
scald regardless of whether
storage.

Id range in
s at least
ess suscept
icier condi
picked appl
torage (unt
Id when the
s. With ot
ariably mor
it is held

flesh firmness
50 percent red
ible to storage
tion in April and
es. However,
il January or Feb

fruit is more
her varieties,
e susceptible to
in regular or CA

8 -

Immature fruit of all varieties is subject to more bitter
pit, shriveling, and brown core during storage than more
mature apples.

Overmature fruit is more susceptible to water core, inter-
nal breakdown, flesh softening and rots than less mature
fruit either prior to harvest or during storage.

Avoid excessively large fruit of a given variety when
selecting apples for long-term storage. Such fruit have
much poorer keeping quality than smaller sizes. Usually
fruit from light bearing older trees and from very young
trees are often unsuited for CA storage because of their
large size.

Alar-85*-treated Mcintosh scheduled for storage should be
harvested at the same time as untreated fruit even though
the Alar- 85- sprayed fruit may be a pound or two firmer
than similar apples which have received no Alar-85. Most
of the flesh firmness advantage Alar-85- sprayed fruit pos-
sesses at harvest is lost during the first few months of
storage. The prime value of Alar-85 on bearing Mcintosh
trees is to provide superior preharvest drop control dur-
ing the latter part of their picking season rather than
serve this purpose when Mcintosh for CA storage should be
harvested (early part of the picking season) . The magni-
tude of preharvest drop is often relatively minor early
in the Mcintosh harvest season and can be controlled quite
well with NAA (naphthaleneacetic acid) .

Late varieties which may be frozen on the trees should
never be harvested until the fruit thaws completely. Har-
vesting frozen fruit will result in visible injury at
points where they are grasped by pickers and wherever
they come into forceful contact with other fruit in pick-
ing or storage containers. Apples which have been frozen
can be expected to have hastened flesh softening (even if
no visible injury is present after thawing) and a short-
ened storage life. The lower the freezing point between
22° and 28"F, the greater the potential loss of flesh
firmness. Dispose of such fruit as rapidly as possible.
If the fruit temperature falls below 22°F, visible injury
to the fruit tissue can be expected once thawing takes
place.

All varieties subject to storage scald should be treated
prior to storage with a suitable inhibitor if they are to
be stored beyond early January. Suggestions for prestor-
age treatments to control storage scald and decay organ-

*Trade name

Storage

9 -

isms can be obtained from your Regional Fruit Specialists

Harvested fruit should be moved into storage no later
than 12 to 24 hours after picking. Long delays between
harvesting and storage result in greater susceptibility
of CA Mcintosh to scald, other senescence disorders, and
loss of flesh firmness.

1. Ideally, apples placed in storage should be cooled from
field temperatures to 32°F within 24-36 hours. Rapid
cooling of apples following harvest is of major importance
in maximizing their marketable life. Rapid removal of
the field heat from fruit stored in bins or boxes requires
recognition and understanding of proper stacking proce-
dures to obtain the best possible rate of heat exchange
from fruit in the center of these containers to the cool-
ing unit. If an extended period is required to reduce
the temperature to 32°F, one can expect a much more rapid
deterioration of the fruit from senescence disorders and
loss of flesh firmness than would result following fast
cooling to 32°F.

2. When apples are placed in CA storage, we recommend a de-
lay in sealing the room until the fruit is cooled to 32°F
even though the CA room (as for Mcintosh) will be held

at 38°F after the room is sealed. However, complete load-
ing and proper cooling of an individual CA room should be
accomplished in about 2 weeks. Any extension of this per-
iod, particularly for Mcintosh, may result in a substan-
tial increase in their storage scald susceptibility. Gen-
erally, CA storage tends to reduce the scald susceptibil-
ity of Mcintosh as compared to similar fruit held in reg-
ular storage. However, delaying the sealing and CA at-
mosphere development for 3 to 5 weeks beyond the time
Mcintosh are initially loaded into a room may make this
variety about as susceptible to scald as similar fruit
placed in regular cold storage. Of course, if long per-
iods of time are required before a CA room for Mcintosh
can be sealed, the application of a scald inhibitor is
essential .

3. Since questions are frequently asked concerning the at-
mosphere and temperature requirement for CA storage of
apples, the following table represents our present recom-
mendations.

Variety

Cortland*

Macoun

Mcintosh

Baldwin

Cortland*

Delicious

Empire

Golden Delicious

Idared

Northern Spy

Rome Beauty

Spartan

Carbon dioxide

Oxygen

Temperature

(Percent)

(Percent)
3

(Degrees F)

*Cortland
listed.

may be stored at either CA atmospheres and temperatures

Varieties with the same CA atmosphere and temperature require-
ments can be stored together providing the room can be fully loaded,
cooled and ready for sealing in approximately 2 weeks.

isicicicitii*1:1ei:iciticit'k

Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whaley
Director
Cooperative Agricultural Extension Work
Acts of May 8 and June 30, 1914

Official Business

Penalty for Private Use, S300.

POSTAGE AND FEES PAID

U. S. DEPARTMENT OF

AGRICULTURE

AGR101

BULK THIRD CLASS MAIL PERMIT

FRUIT
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 42 (No.6)
NOVEMBER-DECEMBER 1977

TABLE OF CONTENTS

New England Fruit Meetings and Trade Show

Mulching Strawberries for Winter Protection

Proceedings of the National Controlled Atmosphere Research

Conference
A Visitor's View of the Apple Industry in British Columbia
Apple Aphid Control Through Natural Enemies
Trends of Michigan Tree Fruit Industry — Part I
Fruit Notes Index for 1977

NEW ENGLAND FRUIT MEETINGS AND TRADE SHOW

The New England Fruit Meetings and Trade Show will be held at
the New Hampshire Highway Hotel, Concord, New Hampshire. The meet-
ings are scheduled for January 4 and 5, 1978.

The hotel is accessible from all major highways. Routes 3
and 93, which lead to Concord, are accessible from anywhere in Mass-
achusetts. Persons coming from Western Massachusetts and Southern
Vermont may find the most convenient route to be Routes 9 or 10 to
Keene, New Hampshire, and then Routes 9 and US 202, 89 and 93 to the
Highway Hotel.

***************

MULCHING STRAWBERRIES FOR WINTER PROTECTION

Richard Marini, Research Technologist
University of Vermont, Burlington, Vt .

Winter injury is often one of the most limiting factors for
strawberry production in northern regions. Although most New Eng-
land growers mulch their plants in the fall to prevent winter in-
jury, it may still occur, especially when snow-cover is lacking.
Nevertheless, growers recognize the value of mulch but are often
unsure when to apply it and how much to use. A brief review of
the physiological changes occurring in strawberry plants during
the fall may help eliminate some of the confusion.

Plants generally develop hardiness in response to fall envi-
ronmental conditions. Strawberries cease growing and enter rest
in late-summer and early-fall as daylength and temperatures decrease.
During this time, sugars accumulate in the leaves and roots, leaves
become less upright, and red color may develop in petioles and
leaves. Hardiness increases significantly after exposure to several
frosts, but may be reduced by subsequent warm, weather. Cool weather
is then needed to regain the lost hardiness. Strawberries usually
continue to harden into mid-winter.

Because hardening conditions are not the same each fall, the
rate of hardiness development and the degree of hardiness attained
differs from year to year. If mulch is applied before near freez-
ing temperatures occur, plants often fail to harden sufficiently,
and may be injured more severely than unmulched plants. Therefore,
mulch should not be applied according to the calendar date, but on
the basis- of fall weather conditions. Researchers in Minnesota (1)
found plants mulched in early October were killed when exposed to
27°F, while those mulched in early November survived 18°F. Although
the critical temperature varies with the variety, well-hardened

- 2

plants may be severely injured or killed when exposed to 10°F,
while blossom primordia in the cro\>ms may be injured at 25°F. A
good rule to follow is to mulch after several days of near-freez-
ing temperatures, but prior to severe cold.

Many materials are used for mulch. They should be free of
weed seed, and be loose and light so as not to mat down, but heavy
enough so that it will not blow away. Canadian researchers (2)
found straw provided better protection than sawdust or wood chips.
Marsh hay appears to be as effective as straw. Both of these ma-
terials lose much of their insulative properties when they become
wet, ice-filled, or matted down.

We have monitored strawberry crown temperatures under several
mulching treatments (Table 1).

Table 1 . Minimum air temperatures, minimum temperatures of straw-
berry crowns of mulched and unmulched plants, and snow depth. Data
were collected in 1966 and 1975.

Air temp. Snow depth Straw mulch

C°F) (inches) (tons/A)

197 5

-6 8 3

-6 8 6

-6 8

-6

1966

-18 6

-18

-12 7 6

-12 7

With an air temperature of -6% plant crown temperature was
27°F under both 3 and 6 tons of straw/A, with 8 inches of snow
cover. Plants with 8 inches of snow but which were not mulched
had crown temperature of 24°F. Plants that were not mulched and
lacked snow cover were at 3°F, which is below the critical temper-
ature for strawberry plants. Crown temperatures are influenced by
the present temperature as well as the temperature of several pre-
vious days. For example: in 1975, there were 5 consecutive days
when the temperature fell below 15°F. The next day was -6°F and at
that time the crown temperatures were 3°F. In 1966, however, sever-
al warm days followed by a temperature of -18°F produced a higher
crown temperature of 5°F.

The data in Table 1 suggest that mulch provides little addi-
tional protection when plants are covered with 7 inches or more of
snow. Whfen snow cover is lacking, however, 6 tons of straw per

rown t
(°F)

emp

3 -

acre may provide up to 15*? protection. Mulching at rates greater
than 3 tons/A would probably add little protection especially in
areas where snow cover is reliable.

LITERATURE CITED

1. Brierley, W.G. and R.H. Landon. 1944. Winter behavior of
strawberry plants. Minn. Agr. Exp. Sta. Bui . 375.

2. Collins, W.B. 1966. Effects of winter mulches on strawberry
yields. Proc. Am. Soc. Hort. Sci. 89:331-335.

***************

PROCEEDINGS OF THE NATIONAL CONTROLLED
ATMOSPHERE RESEARCH CONFERENCE

In the Sept. -Oct., 1977, issue of Fruit Notes , we presented
some of the points discussed at the National Controlled Atmosphere
Research Conference held in April, 1977. The full proceedings of
the conference are now available. They consist of 300 pages of in-
formation on CA and hypobaric storage structures and equipment,
transport research and applications, quality maintenance, prestor-
age treatments with CO2, atmosphere modification, and insect and
disease control during^ storage. It concludes with specific re-
quirements and recommendations for transport and storage of indi-
divual crops.

These proceedings are available for $8. 00, postage paid, for
U.S. and Canadian delivery, and $9.00, postage paid, for overseas
delivery. Please request Horticultural Report No. 28, and enclose
a check or money order written to the order of Michigan State Uni -
versity . However, this order should be sent to the Department of
Horticulture, Michigan State University, East Lansing, Michigan
48824.

***************

A VISITOR'S VIEW OF THE APPLE INDUSTRY IN BRITISH COLUMBIA

Duane Greene
Department of Plant and Soil Sciences

The major fruit growing area in British Columbia is centered
in a narrow band in the Okanogan Valley extending from the Washing-
ton State border north about 100 miles. Orchards in general are

- 4 -

quite small and many growers depend upon apple production as a sup-
plement to other income. Expansion of the industry will be limited
because most good sites are now in production and orchards estab-
lished further north are likely to be damaged by periodic winter
freezes.

There are about 33,000 acres of fruit trees in British Columbia,
with 25,000 of these being planted to apples. Apple production gen-
erally ranges between 9 and 10 million bushels. Approximately 401
of the apples are Delicious, 30% Mcintosh, 10% each of Golden Deli-
cious and Spartan and the remaining 101 miscellaneous varieties.
The acreage of Spartan is not expected to increase due to a serious
problem with internal breakdown in storage. There are relatively
few old orchards due to freezes during the past 10-12 years. This
has made possible the replacement of these older orchards with more
acceptable varieties and strains.

Most fruit growers are planting trees on size-controlling root-
stocks. One of the most important factors when choosing a rootstock
in British Columbia is its susceptibility to collar rot. Many of the
commonly-planted rootstocks in Massachusetts, including M. 7 and M.106,
are too susceptible to collar rot to be planted extensively. However,
the vigorous rootstock M.4 has been used successfully because of its
resistance to the disease. Recently, M.26 has become popular because
it induces early bearing, partial dwarfing, and has resistance to
collar rot. Under British Columbia conditions, it produces a tree
similar to or slightly smaller than one on M.7.

Orchards in British Columbia are being planted heavily to spur-
type Mcintosh and Delicious. It was estimated that for every non-
spur Mcintosh being planted there were 10 spur-type Mcintosh going
into the ground.

Tree spacing in British Columbia is generally closer than that
presently suggested in Massachusetts. A number of growers have
planted spur Mcintosh 8 x 18 ft or spur Delicious 10 x 20 ft on M.4
roots, with the intention of removing every other tree when the
trees begin to crowd. However, a poor orchard often results because
tree removal is delayed and the lower limbs become weak.

The fertilizer program followed in British Columbia differs
in many respects from that in Massachusetts. All orchards are defi-
cient in boron C^) . A lack of B can result in poor tree growth and
a light crop of misshapen fruit. It is recommended that broadcast
applications of B be made every third year in early August. However,
many growers apply B solely in the spring as a spray application.

B deficiency appeared in many British Columbia orchards in
1977. In many cases, the injury was severe enough to reduce the
crop. This situation occurred, in most instances, in orchards where
no late-fdll irrigation was applied and where the grower had not
applied B to the soil for many years because of primary reliance
on a summer spray application of B.

Generally, annual applications of nitrogen (N) are made.
Growers are steadily changing from the use of ammonium nitrate
to urea. In many instances, N applications are split, with half
being applied in November and the remainder being spread in the
spring. Calcium, zinc and magnesium may also be deficient and re-
quire application in British Coltombia orchards.

Both pesticides and plant growth regulators are applied with
sprayers delivering about 50 gal/acre. Most growers do not have
spray equipment to make dilute applications.

Chemical thinning of apples, including Mcintosh, is often done
with dinitro materials (Elgetol*). This is applied during the full
bloom period. Elgetol* acts by burning the stigmas of unpollinated
flowers and thus reducing the number of fruit that set. If the
weather turns excessively moist or cool during the first 4 days af-
ter the spray application, serious overthinning and leaf burning
may occur. Sevin* is not used as a thinner because of its detri-
mental effects on the predator mite population. Consequently, the
thinning results I saw in British Columbia on Mcintosh were much
poorer than we would expect to have in Massachusetts. Often there
was overthinning of the bottom limbs and clustered fruit at the
top of the tree. Clusters of fruit were generally broken up by
hand- thinning after June drop.

The major stop-drop compound used on Mcintosh is 2,4,5-TP.
Very serious carryover effects of 2,4,5-TP showed up in the spring
of 1977 from applications made late in the summer of 1976. Delayed
foliation at shoot tips, small leaf size, and reduced fruit set
and fruit size were all symptoms of the carryover effects. This
problem was serious enough to reduce the Mcintosh crop in British
Columbia in 1977. The problem may have been particularly severe
in 1977 because the application of 2,4,5-TP in 1976 was made prior
to and during a period of very hot weather, and also because the
2,4,5-TP was applied as a concentrate spray. Alar-85* is normally
not used as a stop-drop material and NAA apparently is not effec-
tive enough.

Approximately 300,000 boxes of Mcintosh each year are treated
with ethephon to advance ripening for sale of these fruit soon af-
ter harvest. It is recommended that both NAA and 2,4,5-TP be inclu-
ded with the ethephon and that these chemicals be preceded by an ap-
plication of Alar-85* in mid-summer.

Growers are experiencing increasing problems in establishing
trees on old sites. It now is recognized that the poor growth is
due to soil acidity where trees previously grew. Lime has not been
added routinely in the past because the fruit-growing area is arid
and thus the soil has had a pH of 7.0 or greater. In existing

*Trade name

orchards, soil pH between the rows may still be near neutral. How-
ever, in the soil within rows the pH may be well below 5.0. It is
now recommended that lime be added in the rows of an older orchard
before it is removed. Using this method, the lime may be added
more precisely in the areas that require lime and not in the areas
between rows that do not require pH adjustment.

In conclusion, it was interesting to observe the innovations
and contrasts of 'Mcintosh' culture in an area where orchards are
generally small and the weather during the growing season is dry
and sunny. Growers in British Columbia have cultural problems but
they are in many instances different from the ones in Massachusetts,

***************

APPLE APHID CONTROL THROUGH NATURAL ENEMIES

Roger G, Adams, Jr, and Ronald J. Prokopy
Department of Entomology

Aphids are small soft-bodied, pear-shaped insects that may be
either winged or wingless. They may cause considerable injury to
apple and are most easily recognized by the presence of a pair of
tube-shaped structures known as cornicles at the end of their abdo-
mens. In this article, we discuss the apple aphid Aphis pomi and
its natural enemies in Western Massachusetts apple orchards. We
focus in particular on our research on the ecology of its major
predator, a midge. We conclude with new findings on spray mater-
ials which are least toxic to the midges and allow their build-up.

The apple aphid, formerly known as the green apple aphid, may
be found in dense colonies on apple throughout the growing season.
Serious losses may result in commercial orchards if populations are
not suppressed. Apple aphid injury may be caused in a niimber of
^ays . Feeding on fruits may result in the production of "aphis
apples," while foliar feeding may result in leaf curling and stunt-
ing of terminal growth. Aphid excretion of honeydew (a sticky,
sugary waste product visible as clear spots about 1/16 inch in diam-
eter on leaf and fruit surfaces) and subsequent growth of blackish
sooty mold fungus on the honeydew can result in reduced photosyn-
thetic activity of leaves and contamination of fruit. Recent evi-
dence that the apple aphid can artificially transmit the organism
causing fire blight in apples could lower the economic threshold
level for this pest. Currently, several sprays are required

in local orchards to assure successful control. One of the aims
of our apple pest management program is reduction in spray appli-
cations without increased aphid injury. To achieve this aim, we
are hopeful that aphid natural enemies will play a greater role in
aphid control than they now do.

The most frequently reported natural enemies of aphids are
lady beetles, lacewing larvae, syrphid fly larvae, and anthocorid
bugs. However, while studying the natural enemy complex of the
apple aphid in a Western Massachusetts apple orchard, we found
quite a different species to be the dominant predator: the larval
stage of a cecidomyiid midge by the name of Aphidoletes aphidimyza .

The adult midge is a small delicate, fly-like insect which can
lay up to 100 eggs in aphid colonies. The eggs are tiny and orange,
resembling particles of paprika. They hatch into larvae in about
3 days. The larvae are small (about 1/10 inch long), bright orange
colored maggots that feed on many species of aphids. Larval devel-
opment is completed in 7 to 10 days, at which time they drop to the
soil to form cocoons. The complete life cycle from egg to adult
usually takes about 3 weeks. The species overwinters in the soil
as a larva within a cocoon.

Population densities of the apple aphid and its natural enemies
were recorded from 1974 through 1976 in an unsprayed section of an
apple orchard at the Belchertown Fruit Research Center. Throughout
the study period, the cecidomyiid was by far the most abundant pred-
ator found. A total of 1902 individuals appeared on sampled foli-
age. Syrphids were next most common, with 177 individuals found.
Lacewing larvae, lady beetles, and anthocorids appeared only occa-
sionally.

The cecidomyiid was responsible for high apple aphid mortality
and dramatic aphid population reductions. Apple terminals were
caged with various aphid to cecidomyiid density ratios to study
the feeding behavior of the larvae. In every case, those aphid
colonies caged with cecidomyiids were either reduced or decimated
within 12 days. The overall mean number of aphids killed per ceci-
domyiid during its larval development was 28, ranging from 4 to 65,
depending on predator and prey abundance. During feeding, cecido-
myiid larvae paralyze aphids by injecting salivary toxins. Since
there is no struggle by the aphid, killed aphids appear as shriv-
elled, blackish bodies with the mouthparts still anchored in the
leaf.

Our studies showed that predaceous cecidomyiids appear in
Western Massachusetts apple orchards in mid-June. However, by early

June, apple aphid populations have already reached injurious levels

in some orchards. Therefore, despite control of summer apple aphid
populations by the cecidomyiid, it appears too late in the season
to prevent damage due to early-season aphid activities.

Why don't cecidomyiids appear until mid- June? Where do they
overwinter - within or outside the orchard? To find answers to
these questions, emergence cage studies were conducted during the
spring of 1976. Tent-like cages, containing yellow sticky traps
used to capture emerging cecidomyiid adults, were placed in the
Belchertown orchard under leaves which harbored cecidomyiid larvae
the previous fall. On June 11, 4 cecidomyiid adults were captured
within such cages. Thus, a portion, if not the majority, of the
cecidomyiid population overwintered within the apple orchard, but
adults did not emerge until mid-June. This last finding agrees
with the observed first appearance of cecidomyiid eggs on foliage
sampled in previous years. Therefore, due to the lack of biologi-
cal synchrony between predator and prey, the cecidomyiid is unable
to prevent early season aphid damage. The cecidomyiid is still in
the soil in the cocoon stage while early damage is occurring.

For season-long control, apple aphid populations need to be
maintained below economic threshold levels until the cecidomyiid
predator arrives to control summer aphid populations. We believe
that the economic threshold level of the apple aphid (that is, the
point at which some remedial action should be taken) is approxi-
mately 50 apple aphids per terminal leaf.

Drs. Madsen, Peters, and Vakenti of the Summerland Research
Station in British Columbia were able to reduce the number of sprays
needed to obtain apple aphid control by monitoring aphid populations,
Their results are presented in an article entitled "Pest Management:

Experience in Six British Columbia Apple Orchards," which appeared
in the August, 1975 issue of the Canadian Entomologist . Sprays
were recommended when 50 per cent of the leaves sampled were aphid
infested.

Pesticide sprays have been shoi\m to have a detrimental effect
on many natural enemies of pests. For example, syrphid flies are
abundant in late May and June in many commercial orchards. They
lay oval, white eggs about 1/16 of an inch long on apple foliage
in or near aphid colonies. The eggs hatch into grayish-white larvae
which are ferocious aphid predators. However, syrphids are often
though not always, killed by pesticide sprays. Further studies
are needed to determine which materials allow syrphid survival.

We are currently in the process of studying the toxicity of
orchard pesticides to the predaceous cecidomyiid to determine its
susceptibility, tolerance, or resistance to some of the more recom-
mended materials. Cecidomyiid eggs collected from the Belchertown
orchard were placed on adhesive tape affixed to glass slides. The

- 9 -

slides were dipped for 5
dosages equivalent to IX
chemical was replicated 5
mortality was determined
pesticides to young larva
mortality) was determined
72 hours after treatment,
termined by immersing thi
mixtures for 10 seconds,
ment.

seconds in chemi
concentration in

times with 10 e
72 hours after t
e hatching from

by counting the

Toxicity to la

rd and fourth in

Mortality was c

cals mixed with water at

an orchard sprayer. Each
ggs per replicate. Egg
reatment. Toxicity of
treated eggs (early larval

dead larvae on microslides
te instar larvae was de-
star larvae in pesticide
hecked 96 hours after treat-

Table 1. Laboratory toxicity of orchard pesticides to eggs and
larvae of the predaceous cecidomyiid, Aphidoletes aphidimyza .

Pesticide

Imidan 50 WP
Guthion 50 WP
Guthion 50 WP
CFitchburg)
Sevin 50 WP
Zolone 3 EC
Thiodan 50 WP
Systox 6 EC
Phosphamidon 8 EC
Plictran 50 WP
Omite 30 WP
Thiram 50 WP
Captan 50 WP
Glyphosate 4 EC
Check
Check
(Fitchburg)

% early
Dosage/100 % egg larval
gal spray mortality mortality

1-1/2 lbs

5/8 lb

1 lb

1-1/2 pts

1 lb
5 ozs

1/4 pt

5 ozs

1-1/2 lbs

2 lbs
1 lb
4 qts

larval
mortality

72
4
6
8
34
14
6
6
8

4
5

"2T

10
46
32
16
12

8
6
10
8
3

Per ce
Guthion (Be
and 7 2% of
was moderat
toxicity of
mortality o
Marshall Fa
low (6%).
in Aphidole
The Marshal
Guthion tre
lb/100 gal.
which Aphid
had not rec

nt mortality was gener
Ichertown population)
the eggs, respectively
ely toxic to Aphidolet
Guthion to Apnidolete
f eggs collected from
rm in Fitchburg, MA an
Thus, differential Gut
tes populations collec
1 Farm apple orchard i
atments annually for 7
The section of the B
oletes eggs were colle
eived insecticide or m

ally low with the exception of the
and Sevin treatments, where 861
, failed to hatch. Phosphamidon
es eggs. In contrast to the high
s eggs collected from Belchertown,
a" commercial apple orchard at
d treated with Guthion was very
hion resistance appears to exist
ted from 2 areas of the state,
n Fitchburg has received 7 to 8

years at the dosage rate of 1/2
elchertown apple orchard from
cted for use in toxicity tests
iticide treatments for 6 years.

- 10 -

A few materials that were of low toxicity to Aphidoletes eggs
were moderately or highly toxic to young larvae hatching from
treated eggs. Such early larval mortality was highest (571) for
Systox treatments, while Imidan, Thiodan, and Guthion (Fitchburg)
were of moderate toxicity (24 to 38%) to young larvae.

Thiodan was found to be most toxic (46% mortality) to late
instar larvae while Systox was of moderate toxicity (321). The
fungicides Captan and Thiram, the miticides Plictran and Omite,
and the herbicide Glyphosate were all of low toxicity to Aphidoletes
eggs and larvae.

These results show that Guthion, Systox, and Sevin had very
detrimental effects on the predaceous cecidomyiids from Belchertown.
Phosphamidon treatments were moderately toxic to Aphidoletes eggs
and young larvae hatching from treated eggs, thus resulting in over-
all high mortality. Zolone was the only insecticide tested that
had little effect on the eggs and young larvae of Belchertown ceci-
domyiids. However, Zolone has been found to be very highly toxic
to the most important mite predator in Massachusetts, Amblyseius
fallacis (Robert Hislop, personal communication) (see March-April,
1977 issue of Fruit Notes for more information on this mite preda-
tor). Thiodan and Imidan were moderately toxic to Belchertown
cecidomyiids and, according to recent lab tests by Robert Hislop,
of rather low toxicity to A. fallacis . Therefore, Imidan should
be the broad-spectrum insecticide of choice and Thioaan the aphi-
cide of choice if one desires good insect and aphid control while
allowing at least moderate survival and build-up of our most im-
portant aphid and mite predators. The more abundant these preda-
tors, the fewer pesticide applications that are needed.

We emphasize that these findings are based on tests of a sin-
gle population of cecidomyiids which has its own unique genetic
structure and has been exposed over the years to a certain array
of pesticides. The genetic structure and pesticide exposure his-
tory of cecidomyiids undoubtedly varies from orchard to orchard.
Indeed there is some indication from our field observations that
cecidomyiid populations in certain commercial orchards in Massa-
chusetts may be more tolerant of Guthion treatments that Belchertown
populations. We are currently studying this aspect.

In conclusion, we reiterate that the more abundant the aphid
predators, the fewer aphicide applications that are needed.

***************

- 11

TRENDS OF MICHIGAN TREE FRUIT INDUSTRY

Jerome Hull, Jr.
Department of Horticulture
Michigan State University
Part I.

Composition of the Industry

Michigan's fruit industry includes about 66,000 acres (A) of
apple, 41,000 A tart cherry, 13,600 A sweet cherry, 18,000 A peach,
8,000 A plum and 6,500 A pear. Pear acreage has declined rapidly
because of pear psylla and fireblight control problems, low yields,
and declining markets. Peach acreage has also decreased because
of winter injury, 'valsa canker, X-disease, lack of satisfactory
chemical fruit thinning compounds, and need for seasonal labor for
pruning and multiple selective harvesting. The future of the sweet
cherry industry is uncertain. About two-thirds of the crop is
brined for maraschino cherries and the future of this market depends
on development of a satisfactory alternative to the dye that was
recently banned for artificially coloring maraschino cherries.
Many Michigan orchardists grow small acreages of plums because they
are relatively easy to produce and can be readily machine-harvested
with cherry harvesting equipment. About two-thirds of the crop is
processed.

Michigan produces two-thirds of the nation's sour cherry crop
and this crop continues to increase in importance. Several major
changes in this industry offer it an optimistic future. The crop
is mechanically harvested, eliminating a major harvest labor con-
cern. Expanded grower processing provides the producer increased
control over the marketing of his product. The industry has mar-
keting legislation to provide for diversion or "set-aside" in sur-
plus years for market stability, and has a promotion program to
encourage market expansion. The industry has some production and
marketing problems but appears to have a very stable future in
Michigan.

With 66,000 A, apples are the largest tree fruit crop in
Michigan. In the most recent tree survey C1973), the 5 leading
varieties were Delicious (24%), Jonathan (22%), Mcintosh (111),
Golden Delicious (101) and Northern Spy (81). About 801 of the
state's apple acreage was on seedling rootstocks and 20% on size-
control rootstocks. Approximately 14% of the acreage was planted
between 1968-1972 and two-thirds of these trees were on size-control
rootstocks.

■'■Presented at the Annual Summer Meeting of the Massachusetts Fruit
Growers' Association on July 13, 1977.

- 12 -

The 1973 tree census data indicated that Delicious should re-
place Jonathan as the major apple variety. However, much will de-
pend upon the performance of this variety on size-control rootstocks,
since 72% of the Delicious non-bearing acreage in 1973 was on these
types of rootstocks. Delicious is extremely vulnerable to frost
and fruit set is frequently poor.

Mcintosh has been one of Michigan's leading apple varieties
for many years, but non-bearing trees represented a very low per-
cent of the total Mcintosh trees in 1973. This fact plus antici-
pated tree removals indicate that Mcintosh production in Michigan
will decline in the future. The fruit are easily bruised during
harvest and many growers experience difficulty obtaining adequate
red color on this variety. Recent plantings have been primarily
spur-type Mcintosh.

Northern Spy is not being planted heavily. It is very slow to
come into production and is grown primarily for the processing mar-
ket. Growers are more interested in dual purpose apple varieties
and summer varieties. Idared is becoming very popular, since it
bears at an early age, has a semi-spur type growth habit, produces
large attractive fruit which have excellent packout, and stores
well. It has returned a premium to Michigan growers during late-
season marketing periods.

We anticipate an increased production of summer apple varie-
ties because young-bearing trees and non-bearing trees represented
a very high percentage of the total for summer varieties in Michi-
gan orchards in 1973. Paulared and Jerseymac predominate in re-
cent plantings of summer varieties.

Irrigation

Young trees have limited root development and are readily
stunted by prolonged drought conditions. Thus, many orchardists
have found that trickle irrigation is beneficial in young plant-
ings. Dr. A.L. Kenworthy, in our Department of Horticulture, has
also obtained some interesting results applying nitrogen (N) through
the trickle system. He cooperated with 2 commercial orchardists
in northern Michigan and applied N in 4 applications at weekly in-
tervals during June. The treatments consisted of N applied at
the same rate used by the growers when applying a ground applica-
tion in late fall or early spring, and at rates equal to 50 or 25%
of the grower rate. Ammonium nitrate or urea was used depending
on the grower's preference. He found no significant differences
in leaf N among the 3 N rates applied through the trickle irriga-
tion and the ground application applied by the growers. Half as
much nitrogen applied through the trickle irrigation system ap-
peared as effective as the grower's soil application. No yield
differences have been observed.

- 13 -

The drought in the siaimner and fall o£ 1976 markedly affected
Michigan's 1976 apple crop. In a niimber of orchards fruit did not
mature uniformly on the trees suffering from severe moisture stress,
with those around the periphery of the tree ripening earlier than
fruit in the interior of the tree. This phenomenon was not as
pronounced in irrigated orchards.

Harvest

Market demands for larger, redder apples increases the hazard
of internal breakdown of Jonathan fruit. Control of internal
breakdown is now achieved by a pre-storage water dip or drench
treatment with a 4^ calciiun chloride solution. Unfortunately,
calcium chloride is corrosive to most metals; thus, application
equipment must be cleaned after use. Corrosion of nails or other
bin fasteners also can be a problem. A fungicide is added to the
calcium chloride solution to control storage rots. The solution
can be utilized until it becomes excessively contaminated with
accumulated soil or debris.

For many years, Michigan growers obtained adequate scald con-
trol on stored fruit by using DPA at 1000 ppm. In recent years,
it has been necessary to increase the rate to 2000 ppm except for
Jonathan, Idared and late-picked Rome Beauty, for which 1000 ppm
appears to give adequate scald control.

Storage scald is controlled best when fruit is treated at nor-
mal orchard temperatures within a day or so after harvest. Cold
fruit directly from the orchard or from storage for up to 2 weeks
after harvest can be effectively treated for scald control but the
maximum concentration of DPA must be applied. The chemical becomes
less effective as the treatment is delayed but it is better to make
a late application of the material to apples intended for long term
storage than not to treat at all. A fungicide, either thiabendazole
(TBZ) or benomyl, is added to the scald inhibitor solution to pre-
vent widespread development of blue mold, soft rot and gray mold
diseases on apples during subsequent storage and handling.

Ethylene is a gaseous plant hormone that causes fruits to
ripen. It is produced at a constant low rate during the last few
weeks of growth and development of immature fruit. The ethylene
production rate abruptly increases immediately preceding the onset
of ripening, causing the internal atmosphere ethylene concentration
to increase from about 0.1 ppm to 10 to 100 ppm over the course of
several days.

Dr. D.R. Dilley has developed a colorimetric technique that
enables storage operators to detect high ethylene levels in fruits
as they begin to ripen. About 20 fruits are placed in a 10 liter
dessicator, which is then filled with water. A vacuum is applied
for about 5 minutes to withdraw gas from within the fruit. A sam-

- 14 -

pie of this gas, which collects in the head space of the desicca-
tor, is introduced into an ethylene indicator tube which changes
color from yellow to blue-green as the chemical indicator reacts
with ethylene. A 200 ml. gas sample is tested.

Fruit testing about 0.5 ppm of ethylene or less is utilized
for longest term storage. Apples testing about 2.5 ppm or less
are considered satisfactory for mid-term CA and those testing
greater than 5 ppm are used for short-term storage. Making such
prestorage ethylene analysis and storing fruit accordingly has
markedly improved the fruit firmness situation for one of our
major long-term storage operators.

Marketing

A unique experience to Michigan fruit growers in the last
few years is a marketing and bargaining bill known as Public Act
344. This state legislation provides for the establishment of a
grower marketing organization possessing exclusive marketing con-
trol over a fruit crop when 51% of the growers of a specified mar-
keting unit request certification to be the marketing agency for
that commodity. The legislation pertains to marketing of produce
for processing, not fresh market outlets. Processors, desiring
to purchase the product of the grower marketing organization, must
bargain with the organization on price and other terms relative
to marketing of the grower's produce. All growers pay a fee, de-
ducted by the processor, to the association for its bargaining ser-
vices. The constitutionality of the legislation is being challenged
in Michigan courts and growers have varying opinions about it.
It has disrupted some long established grower-processor relation-
ships. In 1976, bargaining returned more money to the Michigan
producer of processed apples than that returned to growers in other
competing areas in the eastern part of the country. There are some
problems to be resolved in the marketing procedures but the other
states are closely observing the performance of PA 344 in Michigan
to determine if similar marketing legislation has merit for their
respective areas.

Expansion of farm marketing through pick-your-own and retail
farm markets has increased and been important to the success of
many orchardists in recent years. It is more intensive in south-
eastern Michigan near the metropolitan Detroit area. However, it
is being performed very successfully by many enterprising fruit
growers throughout Michigan.

(Will be continued in the January-February ^ 1978 issue)

***************

- 15 -

FRUIT NOTES INDEX FOR 1977

(This index of major articles has been prepared for those who keep
a file of Fruit Notes. The number in parenthesis indicates the
pages on which the item appears.)

January -February

Interregional Cooperative Research in Fruit Tree Viruses

and Aspects of Control Measures: Present and Future Cl"4)

When Should an Existing Orchard be Replaced (4-7)

Cleaning the Weed Sprayer (7-8)

A Substance That Deters Egglaying by Apple Maggot Flies (8-11)

Establishment and Management of Compact Apple Trees (Part II)

March-April

The Use of a Pressure Tester to Measure Firmness of Apples

(1-4)

Apple Trees on M.26 (4-5)

Mite Predator Studies in Massachusetts Apple Orchards in 1976

(5-7)

Establishment and Management of Compact Apple Trees (Part III)

May-June

Suggestions for Fertilization of Apple Trees in 1977 (1-4)

A One-Two Punch for Weeds in Strawberries (4-5)

Reasons for Deformed Strawberry Fruits (5-6)

Why Irrigation for Strawberries? (7-8)

Alternate Row Spraying for Apple Pests (8-10)

Establishment and Management of Compact Apple Trees (Part IV)

July-August

Considerations in Attempting to Improve the Calcivun Content

of Apples (1-4)
2,4-D for Problem Weeds in Strawberries (4-5)
The Plum Curculio: An Introduction and Summary of Preliminary

Field Observations, 1976 (5-7)
CO2 Treatments for Mcintosh at the Beginning of CA Storage (8-10)

Sept ember -October

The National Controlled Atmosphere Research Conference (1-4)

Monitoring Traps for Blueberry Maggot Flies (4-6)

Some Details to Consider When Harvesting and Storing Apples

(7-10)

November -Dec ember

Mulching Strawberries for Winter Protection (1-3)

A Visitor's View of the Apple Industry in British Columbia (3-6)

Apple Aphid Control Through Natural Enemies (6-10)

Trends of Michigan Tree Fruit Industry (11-14) Part I

- 16 -

All pesticides listed in this publication are registered and cleared
for suggested uses according to Federal registrations and State laws
and regulations in effect on the date of this publication.

When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.

NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

Cooperative Extension Service

University of Massachusetts

Amherst, Massachusetts

R. S. Whaley

Director

Cooperative Agricultural Extension Work

Acts of May 8 and June 30, 1914

POSTAGE AND FEES PAID

U.S. DEPARTMENT OF

AGRICULTURE

AGR 101

Official Business
Penalty for Private Use, $300

BULK THIRD CLASS MAIL PERMIT

DR. WM. J. LOT^D
PLANT & SOIL SCIENCES
FRENCH HALL

0100^

FRUITpf
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS. UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

W. J. LORD AND W. J

EDITORS
BRAMLAGE

Vol. 43 (No. 1)

JANUARY /FEBRUARY 1978

TABLE OF CONTENTS

Varieties of Peaches for Massachusetts

Trends of Michigan Tree Fruit Industry (Part II)

Pomological Paragraph

Supplies for trellising apple trees or growing them

as slender spindles
Shelf Life of Pesticides in Common Use by Fruit Growers
European Apple Sawfly: Biology and Development of an

Adult Monitoring Trap

VARIETIES OF PEACHES FOR MASSACHUSETTS

J.F. Anderson
Department of Plant and Soil Sciences

Variety

Recommended

Flesh

App

roximate

for

color

harvest date*

-42

-41

-40

-38

-32

-30

-28

-25

-23

-18

-16

-12

- 7

+ 3

Erly-Red-Fre

Garnet Beauty

Brighton

Sunhaven

Harbelle

Jerseyland

Reliance

Raritan Rose

Redhaven

Harken

Harbrite

Triogem

Sunhigh

Richhaven

Canadian Harmony

Cresthaven

Elberta

Jerseyqueen

C - Commercial H - Home garden T - Trial

Varieties so marked are not necessarily equally adapted to all
sections of the state.

Y - Yellow flesh * - Days before or + after Elberta

W - White flesh about 9/15

Variety Notes

Erly-Red-Fre An attractive, white-fleshed, freestone peach of
medium to large size. The flavor is excellent. The tree is
vigorous and above average in bud hardiness.

Garnet Beauty* A bud sport of Redhaven. Resembles Redhaven in

color and texture. It is a semi-clingstone. The tree is vig-
orous, productive and hardy.

Brighton* An attractive, high-quality, yellow-fleshed peach. The
fruit is roundish, uniformly medium in size and highly colored.
The flesh is medium firm, juicy, with very good flavor. The pit is
semi-cling. The tree is vigorous, productive and medium-hardy.

*Recommended for trial on basis of performance in other areas.

Sunhaven An attractive, highly colored peach of good quality.

The fruit is variable in size, medium to large. The tree is
productive and above average in bud hardiness.

Harbelle* The fruit is large, attractive, with deep yellow ground
color and a bright red blush. Flesh is a rich yellow, medium
in firmness, of good quality. The stone is semi-free. The
tree is productive and medium in vigor and bud hardiness.

Jerseyland A large, firm, juicy, freestone and of good flavor.
The tree is large, upright and very productive. Bud hardi-
ness is above average.

Reliance A medium-sized, roundish, yellow-fleshed freestone peach
of fair to good flavor. Reliance is recommended as a very
hardy variety for the home fruit planting.

Raritan Rose The fruit is large, round, attractive. The flesh is
white, firm, and juicy. The tree is large, upright-spreading
and productive. Bud hardiness is above average.

Redhaven The medium-sized fruit is highly colored, attractive and
has firm flesh and fair flavor. The tree is very productive
and requires heavy thinning.

Harken* A large, attractive, yellow-fleshed peach. The flesh is
FTrm, juicy, of good quality and the stone is free. The tree
is said to be vigorous, productive, and equal to Redhaven in
bud hardiness.

Harbrite* A large, attractive, yellow- fleshed peach. The flesh
IS medium-firm, juicy and of good flavor. The stone is free.
The tree is said to be very productive, hardy and moderately
vigorous.

Triogem The fruit is medium to large and well-colored. The flesh
IS smooth, firm and has a very good flavor. The tree is medium
to large, fairly vigorous and productive. The buds are of
average hardiness.

Sunhigh A large, highly colored, freestone with firm flesh and

excellent flavor. The tree is medium in size, productive and
susceptible to bacterial spot.

Richhaven A large, attractive, highly colored freestone of very
good quality. The tree is large, vigorous and productive.
Bud hardiness is above average,

Canadian Harmony* A large, highly-colored, yellow-fleshed peach.
The flesh is firm, juicy and of good flavor. The tree is vig-
orous, productive, and about equal to Redhaven in bud hardiness.

Cresthaven* A large, oblate-shaped peach with a dark-red blush.
The bright yellow flesh is firm, juicy and slightly fibrous,
there is some red at the pit. The flavor is very good. The
tree is vigorous, productive and medium in hardiness.

Elberta The fruit is large, fairly attractive and a freestone.

Flesh is firm, juicy and has fair flavor. The tree is large,
vigorous and productive. The tree has wide soil and climatic
adaptibility .

Jerseyqueen A large, attractive, oval-shaped peach. The flesh is
yellow, firm and very good in flavor. The stone is free.
Jerseyqueen is moderate in bud hardinesSo

***************

TRENDS OF MICHIGAN TREE FRUIT INDUSTRY (PART II}

Jerome Hull, Jr.
Department of Horticulture
Michigan State University

Rootstocks

Trees on dwarfing rootstocks have been planted extensively
by Michigan apple growers in recent years. Nevertheless, clonal
rootstocks have not solved all of our apple production problems.
In fact they have introduced additional problems.

Clonal rootstocks used initially were M.2 and M.7. M.2 tended
to be too vigorous and M.7 develops suckers from the rootstock and
gives poor anchorage to the more vigorous varieties, notably Deli-
cious.

MM 106 and IM 111 were popular rootstocks when they became
available in the early 60's. MM 106 is a very productive and pre-
cocious rootstock but often produces a larger tree than antici-
pated, particularly with Mcintosh and Paulared varieties. It also
has been sensitive to cold injury and collar rot, particularly
when planted on poorly drained soils or on some of Michigan's heav-
ier textured soils. MM 111 has not been as dwarfing as desired
and has been slow to initiate bearing on young trees.

M.9, popular for high density plantings, is not well adapted
to Michigan's light textured orchard soils. Trees on this root-
stock are readily stunted by drought and weed competition. The

■'-Part II of talk presented at the Annual Summer Meeting of the
Massachusetts Fruit Growers' Association on July 13, 1977.

4 -

stunted trees fruit early and fail to produce adequate vegetative
growth for ample bearing surface.

Many orchardists are now planting trees on M 26, about which
we have little experience or knowledge. There is also much renewed
interest in M.7 budded higher than in older plantings on this root-
stock, to enable deep planting for better anchorage.

MSU has developed several new apple rootstocks from seed of
open pollinated trees of the Mailing 1 through 16, Alnarp 2 and
Robusta 5. These have been named the MAC (Michigan Apple Clone)
series. The more dwarfing, well-anchored clones are MAC 1,4,9,10,
25,39 and 46. MAC 9 is the most dwarfing, producing trees slightly
larger than M.9 but with better anchorage. Trees on these root-
stocks will soon be under evaluation in commercial orchards.

Research and grower experience with apple trees on clonal
rootstocks indicates such plantings should be placed on the most
desirable fruit sites. Because the trees are smaller, bloom is
much more susceptible to frost injury.

Orchardists have learned that trees on clonal rootstocks re-
quire excellent management practices if tree performance is to
equal grower expectations. This includes site selection, soil
preparation, planting techniques, weed control, soil and moisture
management and early training. Some growers have erred and planted
trees too close together, resulting in crowding before trees begin
to produce fruit. This has prompted interest in transplanting of
established trees and in summer pruning.

Frost Control

High density plantings on size-control rootstocks have accen-
tuated the concern for ideal planting sites for apple orchards be-
cause the smaller tree is much more vulnerable to spring frosts.
Growers with less than ideal sites often find it necessary to con-
sider some method of frost control in high-density plantings.
Frost protection with oil and propane gas has become very expensive.
Overtree sprinkling has been demonstrated to be an effective way
of preventing frost injury. This technique along with wind machines
and helicopters, may become more popular in the future with orchard-
ists requiring occasional frost protection. Research with a foliar
application of rhizobitoxin suggests it may delay bloom several
days to minimize frost injury.

Tree Management

Spur-type Delicious are very popular in both clonal and seed-
ling rootstock plantings. Unfortunately, these trees have not al-
ways performed to grower expectation. The primary cause for disap-
pointment probatly has been management rather than rootstock, tree
density, or a choice of strain.

- 5 -

Early training of young trees to prevent development o£ vigor-
ous upright growth is important as a means of encouraging early
fruiting. Spring-type clothespins can be attached to the leader
above lateral shoots to force the laterals to grow more horizon-
tally. (The snap portion of the clothespin is attached to the
trunk when new lateral branches are 3 to 5 inches in length.) The
clothespins are left in place 3 to 4 weeks. An apple picking bag
is an excellent container for carrying clothespins when you place
them in the trees or remove them later in the season. Round tooth-
picks can also be used on succulent lateral shoots for the same
purpose. They are less expensive than clothespins but take more
time to position in the trees. Either technique promotes develop-
ment of wide-angle scaffold branches.

Many trees require branch spreading the second season. Wire
spreaders 6 to 8 inches in length and cut with a sharp point on
each end work well on upright growing branches in the second sea-
son. If additional spreading is required in subsequent years,
wooden spreaders should be used. Orchardists use either wooden
spreaders with nails inserted in each end of the spreader or wooden
slats with V cuts in each end. Scrap lumber, sawed into varying
lengths with deep V cuts in each end, work satisfactorily. Wooden
spreaders with shallow V cuts are difficult to anchor in the tree
and tend to slip along the scaffold and the leader.

Delicious is not the only variety that requires this detailed
training. Paulared, a popular and heavily-planted summer variety,
requires scaffold spreading over several years. Early spreading
is particularly beneficial with this variety as established scaf-
folds split readily at the point of attachment to the leader during
spreading in subsequent seasons with wooden spreaders.

Our experience with Paulared indicates that it is a rather_
vigorous variety and trees propagated on MM 106 tend to make fairly
large trees. We also note a tendency towards biennial bearing.
Fortunately, chemical thinning seems to overcome this difficulty.
An application of 50 ppm NAD at petal fall or 7.5 ppm of NAA about
10 days after bloom has provided acceptable chemical thinning of
young Paulared trees.

When planting trees on the less vigorous rootstocks (M.9 and
M.26), we usually head the trees at 24 to 30 inches to encourage
scaffold formation at the desired heighth on the trunk. Orchard-
ists heading these trees at 30 to 36 inches often fail to obtain
scaffold development within 2 feet of the soil surface and have
"top-heavy" trees. Removal of the shoots just beneath the apical
bud is an effective method of preventing formation of vigorous com-
peting scaffolds. Establishment of such vigorous scaffolds makes
it very difficult to maintain small tree stature.

Growers observe that leaving more than the usual number of
scaffolds on Starkrimson Delicious results in more consistant an-
nual production.

- 6 -
Summer Pruning

Interest in summer pruning has increased as orchardists have
experienced difficulties with excessive tree vigor in high density
plantings .

Summer pruning of fruit trees means different practices to
different people.

Some orchardists consider summer pruning to be nothing more
than removal of water sprouts, which are removed by hand or with
pruning equipment in mid-season. This pruning removes the vigor-
ous upright current season's shoots developing on the scaffolds
and interior of the tree, especially in the vicinity of large prun-
ing cuts that were made during dormant pruning.

Some clonal rootstocks and some of the interstem trees tend
to grow numerous suckers from the rootstock. Orchardists who prune
these off during the summer often refer to the practice as summer
pruning.

Occasionally, an orchardist will perform dormant season-type
pruning during the growing season. This involves moderate to
heavy pruning with selective branch removal, including heavy cuts.
Apple trees subjected to such pruning in June can be severely weak-
ened or stunted and fruit may fail to grow to optimum size. Flower-
bud initiation may be reduced and there is the possibility of tem-
porarily throwing the tree out of production.

Summer hedging is the summer pruning concept of a few orchard-
ists, but it has presented some problems. Initially, summer hedg-
ing was done in mid-season after the initial flush of growth. Re-
growth occurred the same season in the vicinity of the pruning cuts
resulting in development of "crows feet" type growth on the tree's
periphery. Excessive shading in the tree's interior occurred.
When summer hedging is delayed, less regrowth occurs, thus the most
successful summer hedging of apples is normally performed in mid-
August. Follow-up dormant pruning is also necessary but this con-
sists of numerous fine cuts, thinning out the growth around the
periphery of the tree plus removal of large branches causing crowd-
ing.

Summer pruning of young, vigorous, closely-planted apple trees
that are crowding has consisted of selective heading-back and selec-
tive removal of shoots to reduce tree vigor. Upright vigorous
shoots originating on the main scaffolds are removed. Cutting to
a lateral or to an apple is most dwarfing. Delaying this pruning
until August results in less difficulty with regrowth whereas if
performed in June or early July, regrowth beneath the cut usually
occurs, especially if pruning stubs remain.

Summer pruning to control tree size of bearing trees can af-
fect shoot growth and flowerbud development. Shoots are usually

- 7

pruned back to an apple and non-fruiting limbs are thinned out by
cutting to a lateral branch. Suckers and upright growth are re-
moved. Improved fruit color results and stronger flower buds de-
velop in the interior area of the tree. Some orchardists leave
about two inches of the current season's growth. Buds on this ba-
sal stub often regrow if cuts are made before August.

Peach trees respond more favorably to summer pruning than do
apple trees. Pruning is usually delayed at least until bloom.
Pruning cuts heal more readily when performed at this time of the
year and the seasonal application of fungicides helps to reduce
canker difficulties. Pruning at this time of the year also accom-
plishes some fruit thinning. This pruning is best described as
dormant season-type pruning performed in early summer.

Summer hedging of peach trees has some advantages. The hedge-
row concept of peach culture being researched at Purdue University
involves summer pruning to dwarf the tree. Some Michigan orchard-
ists have practiced mechanical topping of peach trees not trained
to a hedgerow. The trees are mechanically topped and sometimes
hedged in late July to control tree height and to admit liglit into
the tree. There is very little regrowth the same season. Growth
in the top of the trees the following season is less vigorous than
that normally experienced with dormant-season hedging. Some vibra-
tion of the tree occurs during mechanical hedging and the nearer
to harvest the practice is performed, the more fruit is shaken from
the tree. Experience suggests that the tree should be very vigor-
ous before being subjected to hedging.

Mechanical topping and hedging stiffens the scaffold branches
and more growth occurs in the lower part of the tree. Admitting
light to the interior of the tree has made possible the retention
of more fine wood over a longer period of time. After several
years, one peach grower had to thin-out the bottom area of the
topped trees to enable pickers to reach fruit in the lower inter-
ior of the tree during harvest.

Peach trees subjected to severe early-season summer hedging
have sometimes been severely winter-injured the following winter
if extreme winter temperatures occur.

(Will he continued, in the Maroh-April^ 1978 issue)

***************

POMOLOGICAL PARAGRAPH

Supplies for trellising apple trees or growing them as slender
spindles^ WT. Loren dT Tukey, 103 Tyson Building, University Park,
Pa. 16802, has compiled a listing of commercial suppliers of mater-
ials used in training trees on trellises or as slender spindles.

You can obtain a copy of this list from Dr. Tukey.

SHELF LIFE OF PESTICIDES IN COMMON USE BY FRUIT GROWERS

Jeffrey Carlson
Assistant Pesticide Coordinator
Department of Entomology
University of Massachusetts

Fruit growers frequently ask how long pesticides can be stored
and still be effective. To answer this question, we have obtained
information on 10 fruit pesticides in common use by consulting the
manufacturers of these chemicals. The information below can give
only a general idea of the shelf life as it is ultimately deter-
mined by conditions of storage, as well as chemical stability. The
following storage conditions should be observed, also, please con-
sult the label for any specific conditions for particular chemicals.

1. Store pesticides in a dry, well-ventilated place at tem-
peratures above freezing.

2. Always keep a pesticide in its original container and make
sure it is tightly sealed.

3. Store granular or powdered materials above the ground to
avoid dampness.

4. Keep the temperature under 100°F if storing volatile com-
pounds.

5. Keep volatile herbicides separate from other pesticides
to avoid contamination.

6. Keep an accurate inventory of the stored chemicals. It is
to your benefit to use up the pesticides that you've purchased as
soon as possible. Don't forget about them in the back room. Rotate
stock; use older materials first!

Common Name (Trade Name) Shelf Life Comments

phosmet,WP (Imidan) 2-3 years Good stability under nor-
mal storage conditions.

dodine,WP (Cyprex) 2-3 years Could be stored up to 5

years provided container
is tightly closed and
the room is kept cool
and dry.

azinphos-methyl,WP 2 years Under normal storage con-

(Guthion) ditions.

thiram,WP (Thylate) 4 years If kept dry, package is

sealed tightly, and is
stored at temperature un-
der 100°F.

- 9

Common Name (Trade Name) Shelf Life
simazine,WP (Princep) Indefinite

ammonium sulfamate, sol'
uble salt (Ammate X)

carbaryl.WP (Sevin)

At least 2
years

several
years

Comments

Has been stored as long
as 9 years under good
conditions .

No low temperature limit
but keep dry and under
100°F.

Wettable powder formula-
tions have been stored
up to 5 years without
loss of effectiveness.

captan,WP
paraquat, liquid
(Paraquat CL)
captafol, flowable
(Difolatan)

3 years
Indefinite

at least
3 years

Settling may occur in
flowable formulations.

It is important to shake
the container in order to
re-suspend components be-
fore using.
Under normal storage.
Extremely stable, no prob-
lems with storage.
After 2 years will tend
to settle, needs good
agitation.

***************

EUROPEAN APPLE SAWFLY: BIOLOGY AND DEVELOPMENT
OF AN ADULT MONITORING TRAP

Elizabeth D. Owens and Ronald J. Prokopy
Department of Entomology

One of Massachusetts' more serious apple insect pests, the
European Apple Sawfly (EAS) , is a recent invader of North America.
It was first discovered on Long Island in 1939, and may have been
introduced there in the cocoon stage in root balls of ornamental
crab apple trees imported from Europe. Since its introduction, it
has spread through many of the fruit growing areas of the Northeast
and is particularly troublesome in the New England states.

EAS adults first appear in apple orchards during full pink.
The small, inconspicuous, wasp-like insect is not often observed
by orchardists. When seen among the open flowers, it appears lit-
tle different from other small insect pollinators, being dark-bod-
ied with a yellowish head and underside, and having clear wings.

- 10 -

It is during bloom that female EAS deposit their small white
eggs in the developing fruit. The egg-laying scar appears as a tiny-
brownish spot near the top of the caylx cup. The larvae hatch in
about 10 days, with the first visible larval feeding damage being
a small dark brown trail tunneled near the surface of the fruit.
As a sawfly larva develops, it takes on the appearance of a dark-
headed white caterpillar which migrates from fruit to fruit, tun-
neling directly to the core and feeding. Later larval damage is
characterized by large masses of dark-colored frass at the feeding
tunnel entrances. Most EAS-damaged fruit is lost during June drop.
However, some remain on the tree and appear at harvest scarred
with long yellowish scabs originating at the caylx and winding
around the fruit surface.

It takes about 3 weeks and 4 to 5 fruits for a sawfly larva
to mature. It then drops to the soil where it forms a cocoon, re-
maining in that state until adult emergence the following spring.
Thus, there is only one generation annually.

Most commercial apple orchards do not have a population of
sawflies arising from within the orchard, the reason being that
standard pesticide spray programs include a petal fall spray which,
if applied at the appropriate time, kills most or all of the lar-
vae. However, since most New England orchards are surrounded by
areas dotted with wild or abandoned apple trees, there is a contin-
ued threat of invasion by sawfly adults migrating in from the out-
side. To improve the orchardist's ability to determine if EAS is
active in his orchard and, if so, to aid in the appropriate timing
of spray applications against sawfly, we initiated the following
research aimed at development of an effective and convenient trap
for monitoring EAS adult population levels.

First, we spent many hours observing EAS adult activity in
abandoned apple trees. Females were watched as they flew about
blossoming trees on warm sunny days in May. We observed them
feeding on pollen in open or partially opened blossoms and laying
eggs in the caylx cup. Most adults were seen to land near or di-
rectly on the blossoms. This information led us to study (with
the aid of a spectrophotometer) the visual reflectance pattern of
apple blossom parts and to field test white surfaces that might
prove to be effective blossom mimics.

In our first experiment, conducted in an abandoned orchard,
we compared 6x8 inch rectangles hung vertically from apple tree
branches and coated with the following colors of enamel paint:
white, gray, black, yellow, green, blue, orange, or red. Clear
plexiglas and aluminum-foil-covered rectangles were also tested.
All traps were coated with a thin layer of Bird Tanglefoot*, a
clear sticky substance that captures alighting insects. The
results (Table 1) show that more EAS were captured on the white
rectangles than any others tested. The fact that white captured

*Trade name

- 11

more than clear plexiglas ( = a neutral surface ) indicates that
EAS captures on white were the result of positive attraction and
not simply random collision.

Table 1. Comparative captures of EAS adults on rectangles of var-
ious colors. 7 replicates.

Rectangle Total No. EAS adults

captured

White 61

Gray 25

Clear plexiglas 18

Yellow 3

Aluminum foil 1

Black 1

Red 1

Green

Orange

Spectrophotometer analysis of light reflected from apple blos-
som petals and all other blossom parts (stamen, pistal, etc.) showed
all flower parts to be high in reflectance at wavelengths from 400-
650 nm, and very low in reflectance in the ultra-violet part of the
spectrum (300-400 nm) . The human visible spectrum is 400-700 nm;
the insect visible spectrum is 300-650 nm.

In our second test, we therefore compared 5 types of white
rectangles: zinc oxide, Day Glo primer, white enamel, lead oxide,
and Zoecon pre-dyed white cardboard. The first three were low in
ultra-violet reflectance (as were apple blossoms) and the last two
were high in UV reflectance (unlike the blossoms).

The results (Table 2) showed that zinc white, which most close-
ly mimics apple blossoms in color reflectance pattern, captured the
most EAS. Day Glo and enamel whites captured nearly as many EAS
as the zinc white, but Zoecon and lead white, which were poor mimics
of apple blossom reflectance patterns, were not at all attractive
to EAS. These results indicate that sticky-coated rectangles coated
with either zinc oxide white or Day Glo primer white could be used
to monitor EAS activity.

Table 2. Comparative captures of EAS adults on rectangles of vari-
ous white surfaces. 10 replicates. ^__^

Rectangl? Total No. EAS adults

captured

Zinc white 90

Day Glo primer 62

White enamel 49

Zoecon white 3

Lead white

- 12

LTTlUm

Although further work is necessary to determine the optii

shape and placement of the traps, our research to date has resulted
in an effective and convenient monitoring trap for adult EAS during
apple bloom. Because most orchardists use domestic honeybees for
pollination, it should be noted that the rectangular zinc white or
Day Glo primer white traps were not very attractive to bees. In
the next issue of Fruit Notes , we will discuss our research showing
that such white traps are also effective for monitoring tarnished
plant bug adult populations in apple orchards.

***************

All pesticides listed in this publication are registered and cleared
for suggested uses according to Federal registrations and State laws
and regulations in effect on the date of this publication.

When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials,

NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

WARNING: PESTICIDES ARE POISONOUS. READ AND FOLLOW ALL DIRECTIONS
AND SAFETY PRECAUTIONS ON LABELS. HANDLE CAREFULLY AND STORE IN
ORIGINAL LABELED CONTAINERS OUT OF REACH OF CHILDREN, PETS AN LIVE-
STOCK. DISPOSE OF EMPTY CONTAINERS RIGHT AWAY, IN A SAFE MANNER
AND PLACE. DO NOT CONTAMINATE FORAGE, STREAMS AND PONDS.

Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whaley
Director
Cooperative Agricultural Extension Work
Acts of May 8 and June 30, 1914

Official Business
Penalty for Private Use, $300.

POSTAGE AND FEES PAID

U. S. DEPARTMENT OF

AGRICULTURE

AGR 101

BULK THIRD CLASS MAIL PERMIT

FRUIT
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 43 (No. 2)
MARCH /APRIL 1978

TABLE OF CONTENTS

Varieties of Raspberries and Blackberries for
Massachusetts

Pomological Paragraph
Publication Available

Partial Budgeting of Management Alternatives for
Fruit Growers

Pomological Paragraph

Apple Production Costs in Pennsylvania in 1975

Trends of Michigan Tree Fruit Industry - Part III

Tarnished Plant Bug on Apple: Damage and
Monitoring Traps

VARIETIES OF RASPBERRIES AND BLACKBERRIES
FOR MASSACHUSETTS

James F. Anderson
Department of Plant and Soil Sciences

Variety

Gatineau

Heritage

Madawaska

Taylor

Latham

Sumner

Heritage

Clyde

Brandywine

Bristol

Type

Recommended for

Red

C 5 H

T
C 5 H
limited
C 5 H

Harvesting Season

C
C

Purple

Black

Very early

Early

Midseason

Late

Late Sept.

Late

Early

T = Trial H = Home garden C = Commercial
Varieties so marked are not necessarily equally adapted to all
sections of the state.

*It is recommended that only Registered or Certified plant stock
be used in establishing new raspberry plantings.

Gatineau

Heritage

Madawaska

Taylor

Latham

Variety Notes

The fruit is large, firm, good quality and moderate-
ly attractive. The plant is vigorous, productive
and moderately winter hardy.

Most often grown for the fall crop only. The summer
crop is said to be moderate in production and the
fruits slightly smaller than those produced in the
fall.

Produces large, firm fruit of good quality and medium
red color. The plant is vigorous, productive and
winter hardy. It is susceptible to spurblight.

Has been grown successfully on a commercial scale
in the high elevations of Worcester and Franklin
counties. Where it remains free of virus, the plants
are tall, vigorous, hardy and productive and the
fruits large, firm and have very good flavor.

The fruit is of good size, bright red in color and
of average firmness and flavor. The plants are vigor-
ous, productive and hardy when spurblight is con-
trolled. Latham is susceptible to spurblight.

- 2 -

Sumner The fruit is medium to large size, firm, and have
very good flavor. The plants are hardy, vigorous
and productive. Appears adapted to heavier soils.

Heritage The berries of the fall crop are medium-sized, very

firm, coherent, attractive and of very good flavor.
The plants are vigorous and productive.

Clyde A large fruited purple raspberry. The berries are

attractive, firm, tart, and good in quality. The
plants are very vigorous, hardy and productive.
Clyde is most suitable for culinary use.

Brandywine A new introduction from New York. The berries are

said to be large, round, reddish-purple, firm, coher-
ent, tart but of good quality. The plants are very
vigorous and productive. Said to make a fine flavored
jam.

Bristol Black raspberries are not generally satisfactory in
Massachusetts because of their great susceptibility
to virus diseases. Bristol is one of the more desir-
able varieties. It produces large attractive, firm
berries of good quality. The plants are vigorous,
and productive as long as they remain free from virus
diseases.

Blackberry Varieties

Darrow The plants are hardy, vigorous and productive. The

berries are large, firm, attractive and have good
flavor.

Trailing types, such as Boysenberry, Loganberry and Youngberry are
not sufficiently winter hardy and productive in most parts of the
state. However, the Boysenberry has been reported as reasonably
satisfactory in a few locations.

***************

POMOLOGICAL PARAGRAPH

Publication Available . Bulletin No. C-102 entitled "Establishment
and Management of Compact Apple Trees" is available for 75 cents
from The Bulletin Center, Cottage A, Thatcher Way, University of
Massachusetts, Amherst, Mass. 01003. Make check or money order
payable to the Massachusetts Cooperative Extension Service and send
it to the address given above. This publication has under one
cover the information on establishment and management of compact
apple trees that appeared in serial form in Fruit Notes during 1976
and 1977.

PARTIAL BUDGETING OF MANAGEMENT ALTERNATIVES
FOR FRUIT GROWERS

Robert L. Christensen
Department of Food and Resource Economics

Introduction

Fruit growers must make many decisions o£ both a short-term or
long run nature. These decisions can range from those involving
replacement of blocks or choice of varieties (which are very long run
in nature) or those such as selecting a spray program, deciding on
the size of a picking crew and purchase of packaging materials (which
are short run in impact). Decisions can be of significant magnitude
in a monetary sense or relatively insignificant. It is obvious that
as the magnitude of financial committment increases, the attention
paid to the consequences of such a decision on profitability should
also increase.

The most important function of management is the planning and
evaluation of the alternative courses of action that can be taken.
The decision-making function is the true meaning of management.
Thus, it is important that a manager become fully knowledgeable
with the concepts of costs, revenues, and profits. He also must
have a decision-making framework or "procedure" that he can follow
in developing and analyzing his data so that the profitability of a
course of action can be established. It should be clear that the
exercise is one of planning or anticipating future events. This
means that the manager must make some assumptions or projections with
regard to expected future prices, costs, yields, and the like. It
also means that if these projections turn out to be in error, then
the decision made may also be in error. Thus, the importance of
good information from records, farm research, or other sources
should be obvious.

Budgeting as a Tool for Decision Making

Budgeting is the pencil and paper testing of the consequences
of a decision before actually making it. It consists of projecting
the costs and returns resulting from a course of action into the
future and thus calculating the probable effects on net earnings.

Since few managers will knowingly make a decision that is shown
to be unprofitable, it is important that a manager have the best
information available and that he knows how to use this information
to assist him in assessing the profitability of the decision.

The technique to be described and illustrated here is that of
partial budgeting . It is the most easily understood and most widely
applicable of all of the economic decision making tools. Some of
the other advantages are as follows:

- 4 -

1. Budgeting is adaptable to individual farm situations.

2. Budgeting is a framework for dealing with prices, costs and !
yields and can be used to analyze the effects of changes

in any of these economic variables.

3. Budgets can be adjusted to reflect the differences in
managerial ability.

4. Budgeting enables the comparison between alternatives.

5. Budgeting can be used to analyze the impact of a specific
adjustment (partial budgeting) or changes affecting the
entire business (complete budgeting) .

Budgeting Applied to an Orchard Situation

Before budgeting begins, it is necessary to select the alter-
natives for which budgeting is to be conducted. In the hypothetical
example illustrated in this paper, we wish to evaluate the economic
consequences of full row spraying for pest control versus alternate
row spraying. This is an excellent example of a decision where
partial budgeting is appropriate.

Partial budgeting is used when considering a change in only one
aspect of the operation. The focus is on only those things that will
change as a result of the decision. Thus, the information needs are
identified as those changes. Identifying the nature of the changes
that will occur is the first step. In the problem of evaluating the
impact of alternative row spraying, we can identify the following
factors :

(1) Spray materials

(2) Tractor and sprayer time

(3) Labor time

(4) Fruit damage

(5) Yield

There may be other factors that could be relevant but are non-
quantifiable or involve information that is not available. For
example, reduced soil compaction may be beneficial while increased
mite or aphid populations may have a long run negative impact on
vigor and yield. However, at present information is lacking on
these impacts and one must, therefore, assume they have no effect.

" Quantifying the Effects of the Alternative "

The next step in the analysis requires the estimation or projection
of the magnitude of the effects on each of the factors. This step
can be illustrated by the following set of questions:

5 -

1. Mow much less spray materials would he needed?

How much less sprayer and tractor time is needed?
What reduction in labor would result?

How much more insect damage on fruit would there be?
What would be the effect on vield?

rind
and most
one's own
However ,
ist over
of inform
adopted t
accurate ,
may not b
and poor
A third s
the Agric
These res
close mon
ensure th
sions mus
individua
experienc
yields .

ing t
accur

orch
this
some
ation
he pr

it i
e the
recor
ource
ultur
ults
itori
at th
t be
1 rat
e of

he answers to these questions is not easy. The best
ate answers would be based on personal experience in
ard under the specific conditions of that orchard,
would imply the conduct of experiments by the orchard-
period of time, which could be a risk. Another source

is the experience of other orchardists who may have
actice. While such information is often valid and
s equally often in error. The particular circumstances

same, other factors may have influenced the results,
ds or memory may yield erroneous or false information.

of information is the research results provided by
.il Experiment Stations and Extension Services,
are nearly always from controlled situations with
ng and collection of data. Every effort is made to
e results are valid and accurate. In many cases deci-
based on information from all three sources, i.e.,
es of spray application and other practices and either
others or research results on effects on quality and

Assuming such information is available, the following illustrates
how these data might be organized for further analysis:

Resource Use for Alternate Spray Methods 1 Acre Block

Full Row

Alternate
Row

Difference

Spray Materials ($) $120

Tractor 5 Sprayer Time

(hrs) 3

Labor Time (hrs) 3

Fruit Damage (^) 2

Yield (bu.) 250

$60

1.75
1.75

3
250

-$60

1.25 hrs.
■1.25 hrs.

6 -

"Converting the Data to Economic Terms"

The next step in the analysis is to convert these data to
economic terms. This involves putting prices or values on each of
the factors. Below is a table with assumed prices for each factor
and the computation of the added or reduced costs.

Factor

Unit Value

No. of
Units

Total Cost

Spray Materials
Tractor ^ Sprayer Time
Labor Time
Damaged Fruit

—

$60.00

$5/hr.

1.25 hrs.

6.25

$3/hr.

1.25 hrs.

3.75

-$4/bu.

2.5 bu.

10.00

"The Partial Budget and Profitability Determination"

The final step is to compile the economic data in the partial
budget. The usual format for the partial budget is as follows:

Added Returns:
(A)

Reduced Returns:
CC)

Reduced Costs:
(B)

Added Costs:

(D)

(A) + (B) = (E)

If (E) is greater than (F) then c
If (E) is less than (F) then dec:

iecision is profitable.
Lsion is unprofitable.

7 -

In the example at hand there are no added returns (A) or added
costs (D) . The only categories o£ relevance are reduced costs (B)
and reduced returns (C) . Therefore, the profitability relation
reduces to the comparison of (B) and (C) . If (B] exceeds (C) tlie
alternative is profitable.

The values comprising reduced costs (B) are:

Spray materials $60.00

Tractor and sprayer 6.25

Labor 5.75

Total (B) $70.00

The only value appearing in (C) , reduced returns, is a reduction
in the value of fruit of $10.

The value of (B) exceeds (C) by $60 which is the indicated
increase in profit per acre which would result from the adoption
of the alternate row spraying method.

"Determination of the Economic Parameters"

The above procedure is quite simple in concept and application
but it avoids the issue of how some of the economic parameters are
obtained. Specifically, the entire question of how equipment costs
are estimated and placed on an hourly basis is not treated. Two
classes of costs are involved: (1) fixed or "ownership" costs and
(2) variable costs. The ownership costs include depreciation,
interest on investment, taxes, insurance, and repairs. Variable
costs include fuel and lubrication. Ownership costs are essentially
a given value for a year and do not vary with acreage while variable
costs are directly proportional to use.

***************

POMOLOGICAL PARAGRAPH

Apple Production Costs in Pennsylvania in 1975 were found to be
$679.68 per acre, according to a study made in Adams and Franklin
Counties by B. Wayne Kelly, Farm Management Extension Specialist
at Pennsylvania State University. Harvesting costs were $196.37/acre
for an average yield of 402 bu/acre, giving a cost harvested at
$2.18/bu. Spraying materials were $91.44, and all labor (less
harvesting) was $212 . 70/acre. In Western Michigan, a study by Myron
Kelsey, Agricultural Economist at Michigan State, indicated that
production costs for a semi-dwarf planting were $518.22/acre and
harvesting costs, $236.19/acre for a yield of 400 bu/acre, giving
a cost harvested at $1.88/bu. Spray materials were $97.49/acre, and
all labor (less harvesting) was $133.27. Although the studies were
not completely comparable (differing somewhat in values and charges),
their results are surprisingly close. -- L. D. Tukey, Penn State ,
Horticultural Reviews. 26 (No. 2). 1977.

-8-

TRENDS OF MICHIGAN TREE FRUIT INDUSTRY (PART III)^

Jerome Hull, Jr.
Department of Horticulture
Michigan State University

Nematodes and Soil Fumigation

Parasitic nematodes have become o£ increased concern to Michi-
gan fruit growers. Many orchards are planted on light-textured
soils and on these soils damaging nematode populations are being
detected in an increasing number of young orchards and orchard
sites. Peach trees are most susceptible to nematode injury in
Michigan. However, cherry trees also are susceptible and nematodes
can be a problem in apple and pear plantings, especially in orchard
replantings .

The root-lesion nematode is of primary concern, although the
dagger, rootknot and lance nematodes may also be present. The usual
nematode damage symptoms are stunted trees with poor vigor. Nema-
tode numbers vary within a field; therefore, tree vigor on the site
is variable.

Some feeding nematodes will induce gall formations on plant
roots. Root cells destroyed by nematode-feeding become dark dis-
colored areas in the root system. These root-lesions increase with
continued feeding and secondary invasion by other soil microorganisms
occurs. Some nematodes feed on young roots and alter the traditional
root branching structure. They may also devitalize or kill roottips.

Soil fumigation prior to planting on old orchard sites is often
essential to produce vigorous healthy orchards. Thus, a laboratory
analysis of soil and root tissue is suggested to detect nematode
problems. The soil and root samples are usually collected about 2
months after the initiation of tree growth in the spring and before
frost in the fall (usually mid-July to mid-September) .

Many fruit crops respond to soil fumigation with nematicides.
This is readily apparent by improved tree growth. A long-term study
in New York has demonstrated a definite financial advantage from
fumigating an apple orchard. In Michigan, increased growth and
winter survival of young peach trees has occurred following fumiga-
tion. Furthermore, fumigation also seems to be associated with
improved weed control in new fruit plantings.

Nematode control is not simple. Proper soil preparation prior
to soil fumigation is essential for maximum nematode control. The
soil must be cultivated to promote thorough decomposition of previous

Part III of Talk presented at the Annual Summer Meeting of the
Massachusetts Fruit Growers' Association on July 13, 1977.

-9-

crop debris because undecayed roots harbor nematodes, protect them
from the fumigant, and interfere with fumigant application. It
should be in excellent tilth and soil moisture should approach that
desirable for seeding. Dry soils permit rapid escape of fumigants
whereas dispersion of fumigants in excessively wet soil is poor.
Fumigants do not volatilize and disperse properly at soil tempera-
tures below 50°F and escape too rapidly from soils when the tempera-
ture is above 80°F. Spring treatment usually delays planting so
late summer or early autumn is usually best for the application of
soil fumigants in Michigan.

Soil fumigation is the primary treatment being utilized by
Michigan orchardists. The fumigant is chiseled 6-10 inches deep
into the soil with the chisels space 8-10 inches apart along the
tool bar. The soil is smoothed with a drag or cultipacker immedi-
ately after application to prevent the chemical from escaping. The
most widely utilized soil fumigants are Vorlex*, DowFume W-85*,
Telone* and Shell D-D*. Methyl Bromide also has been utilized to
treat individual tree sites with an injecting soil auger in the fall
prior to planting. When fumigating orchardists normally treat a
7-foot strip where the tree row will be located rather than treating
the entire field.

Research with granular nematicides applied with fertilizer appli-
cators and rotatilled into the soil is encouraging. There also is
much interest in foliar application of nematicides. Vydate-L* is a
foliar nematicide that can be applied to non-bearing trees. However,
2 to 3 applications per year are necessary. Furthermore, we do not
consider it an alternative to soil fumigation, although yearly appli-
cations until a tree comes into bearing may help suppress nematode
difficulties .

Nemagon* or Fumazone* can be applied as a post-plant row appli-
cation. It must be chiseled into the soil about 8 inches deep along
the tree row. However, it is usually a less effective method than
pre-plant soil fumigation.

Orchard Replant Problems

Another difficulty encountered in establishing fruit plantings
is frequently referred to as the Specific Apple Replant Disease.
This is observed where an apple orchard is replanted to apples.
Young trees planted where the old trees stood may make poor growth,
thus tree growth on the site is variable.

A specific disease has been identified as the cause of this
difficulty in cherry, and work continues to identify the difficulty
in Apple. Chloropicrin is beneficial as a soil treatment for the
Specific Apple Replant Disease. The Dutch have found that using a
potting mixture in the planting hole is useful in preventing poor
vigor because of the disease.

* Trade name

-10-

The use of beneficial bacteria to promote establishment and
growth of young trees is a new area of research. Spectacular bio-
logical control of crown gall, caused by the bacteria Agrobacterium
tumef aciens , has prevented the stunting and poor growth associated
with the gall formation on crown gall-infected trees. An organism
from New Zealand has been reported by the USDA and plant pathologist:
at Agricultural Experiment Stations to promote favorable growth of
fruit trees. Dr. A. Jones, MSU plant pathologist, is using New
Zealand bacteria Agrobacter radiobacter (isolate #84) to inoculate
tree roots by dipping at planting time as well as inoculating the
soil in an attempt to promote growth of young fruit trees in Michi-
gan by preventing crown gall infection.

The exact mechanism of activity by the organism is not known.
Some pathologists believe the isolate occupies sites on the plants
and thus prevents other pathogenic bacteria from, invading the plant
root system.

***************

TARNISHED PLANT BUG ON APPLE: DAMAGE AND MONITORING TRAPS

Ronald J. Prokopy, Karen I. Hauschild, and Roger G. Adams

Department of Entomology

The tarnished plant bug (TPB) is among the 5 most injurious
insect pests of apple fruit in Massachusetts orchards.

From the published literature, we know that TPB adults over-
winter under duff in hedgerows. During the first warm days of
Spring, they begin flying into apple orchards. There, an adult
seeks out a developing flower bud, inserts its beak into the bud,
and sucks up plant sap. After the beak has been removed, sap oozes
from the puncture, sometimes forming a large, readily visible drop-
let. The overwintering adults continue to feed in this manner until
they die, usually by the time of the first cover spray. The adults
rarely lay eggs in apple trees but rather in legumes and other ground
cover plants. Indeed, some of our preliminary findings suggest that
a large amount of vetch, alfalfa, a clover in or near the orchard may
encourage substantial buildup of TPB populations. The eggs hatch into
nymphs, which then give rise to second generation adults. The nymphs
do not feed on apple. Neither, apparently, do the second and third
generation adults -- at least not to the extent of causing noticeable
injury.

Research on TPB was initiated in 1976 because we wanted to learn
more about this insect. Our goals were three-fold: (1) to determine
what types of apple injury result from TPB feeding, and when these
injuries are initiated; (2) to develop some sort of simple, effective
monitoring method for estimating the size of TPB populations in apple

trees; and (3) to accurately relate the numbers of TPB sampled by
this method to the amount of TPB injury. We hoped we could eventually
construct an index or chart which would indicate to the grower that
if X number of TPB adults were taken in the samples, then X amount
of TPB injury could be expected. Based upon the intended market for
the fruit, and therefore the amount of TPB injury the grower felt he
could tolerate, the grower could then decide if it was worthwhile to
spray a pesticide against TPBs. In this article, we report on our
progress to date toward these goals.

To study the nature an
structed a large number of
unsprayed section of orchar
each cage was positioned to
buds on a branch. We intro
and sealed the ends to prev
12, 1977, the day the first
buds were at green tip. Th
after which they were remov
further entry of insects,
new cages every 4-5 days un
days at bloom for pollinati
correlate the stage at whic
to TPBs with the nature and

d occurrence of TPB injury, we first con-
cages made of plastic and cloth. In an
d at the Horticultural Research Center,

completely surround 6-7 developing flower
duced one TPB adult into each of 6 cages
ent escape. The cagings began on April

TPB adult was found in the orchard. The
e TPBs remained in the cages for 4 days,
ed and the cages resealed to prevent
We repeated this procedure with TPBs in
til July 1 (the cages were opened for 4
on). Using this procedure, we could
h developing apple flower buds were exposed

amount of ensuing injury.

The data in Table 1 reveal that feeding by caged TPBs on apple
flower buds at the green tip and half inch green stages caused a
substantial amount of bud abscission. No detectable bud abscission
resulted from TPB feeding initiated at tight cluster or afterward.

TABLE 1

Time of initiation of
injury by TPB adults
in cages

Average number of
flowers per cluster
at full bloom

% decrease
compared with
check

Green tip

Half inch green

Tight cluster onward

Check (cages without TPBs)

3.1
3.7
4.5
4.5

311

18°^

Most years abscission resulting from early season TPB feeding
would not be an important economic consideration. However, in off-
bearing years, years of severe frost damage, or poor pollination,
this bud abscission could be important.

The data in Table 2 reveal that feeding by caged TPBs on buds,
blossoms, and fruit from mid-pink to petal fall caused dimples in a

-12-

large percentage o£ the apples at harvest. Most of the dimples
were near the calyx. Many were deep, but some were shallow and
surrounded by a small (1/16" - 1/4") tan-colored scab. Only a
small percentage o£ dimpled fruit resulted from TPB feeding from
green tip to early pink and from first cover or later.

TABLE 2

Time of initiation of injury % Dimpled fruit

by TPB adults in cages at harvest

Green tip to early pink 12-0

Mid-pink to petal fall 471

First cover or later 9%

Check (cages without TPBs) 0?;

The economic consequences of dimpling injury caused by TPB feed-
ing vary from grower to grower according to the intended market of
the fruit and the severity of dimpling. When you come right down
to it, the dimples are purely cosmetic injuries and affect only the
appearance of the fruit. In no way do the dimples affect the eating
or keeping quality of the fruit, as do injuries by apple maggot, plum
curculio, and codling moth. Most Massachusetts growers with whom we
have spoken feel they can tolerate 1-3% of lightly dimpled fruit in
their cartons of U.S. Fancy or better fruit. Moderately or heavily
dimpled fruit is usually culled.

Our next goal was to develop a method for monitoring the abun-
dance of TPB adults on trees throughout the period when they could
cause injury: silver tip through petal fall. In many crops where
TPB is a pest (e.g. alfalfa, sugarbeets), TPB abundance can be readily
and rather accurately monitored by collecting TPB in sweeps with an
insect net. This method is not useful for collecting TPBs on the
woody twigs and branches of fruit trees, however.

Because plant bugs are rather closely related to aphids, we
suspected that plant bug adults, like aphid adults, might use visual
cues to guide them to their host plants and feeding sites. Our
approach was similar to that which we used in developing a method
of monitoring European apple sawfly populations in apple orchards
(see Fruit Notes 43(1): 9-12). Using a spectrophotometer (an instru-
ment which records the wavelengths of light reflected from surfaces) ,
we measured the spectral reflectance pattern of the surface of all
apple structures susceptible to TPB feeding injury. We also measured
the spectral reflectance pattern of surfaces to which we had applied
various enamel paints. By so doing, we were able to select particular
painted surfaces which closely mimicked the reflectance patterns of

13-

apple structure. The only structure which we could not mimic was
the pink tissue of developing blossoms, which had a reflectance
pattern unlike that of pink, red, or any other paint. We then applied
the paints to 6x8 inch cardboard rectangles, coated the rectangles
with a clear sticky substance (formerly known as "Bird Tanglefoot"
but now called "Tangletrap") to capture alighting TPBs, and hung
the rectangles by wire from low apple tree branches at knee to waist
height.

The results of this test showed that TPB adults alighted in

greatest numbers on white, clear Plexiglas,
and in lesser numbers on gray, green, blue,
rectangles (table 3).

TABLE 3

and yellow rectangles,
red, orange, and black

Color of
Rectangle

No. TPB adults
captured

Color of

No,

. TPB adults

Rectangle

captured

Blue

Red

Black

Orange

White

131

Clear Plexiglas

129

Yellow

109

Gray

Green

The white paint reflected light in the same general pattern as
bud scales, newly unfolding leaves, the calyx cup, and mature blossom
petals. The intensity of reflection from the white w^as greater than
from bud scales, etc., hence giving it the appearance of very bright
bud scales, etc. The yellow paint reflected light in the general
pattern of maturing leaves, but likewise, at greater intensity. The
fact that clear Plexiglas captured just as many TPBs as the white and
yellow rectangle suggests that TPBs were not actually attracted by
the white and yellow surfaces. Rather, it appears that TPBs were
repelled by colors such as red, orange, and black, which have reflec-
tance patterns similar to those of twigs and bark, upon which TPBs
do not feed.

Additional tests revealed that like sawfly adults, TPB adults
discriminate between different types of white surfaces. No apple
structures reflect an appreciable amount of ultra-violet (UV) light.
Consistent with this was our finding that TPBs readily alighted on
white-painted rectangles reflecting a low amount of UV, but were
repelled by white-painted rectangles reflecting moderate or substan-
tial UV. Although to the human eye, IN and non-UV reflecting white
paints are indistinguishable, to the eye of TPB, they obviously are
distinguishable. As things have turned out, the same low-UV-ref lecting

-14-

titaniuH or zinc oxide white-painted rectangle traps that have proven
so attractive to sawfly adults ( Fruit Notes 43(1):9-12) are also the
most effective for TPB adults.

Next, we compared this sticky-coated white rectangle trap with
other methods of monitoring TPB adults in orchards. Each week from
silver tip to petal fall, we examined 25 developing flower buds on
each of 12 unsprayed apple trees at Belchertown for evidence of TPB
injury. At the same time, we counted the number of TPB adults seen
on the 25 buds, and the number collected after making 25 sweeps of
the ground cover foliage under each tree with an insect net. Counts
also were made of the number of TPB adults captured weekly on a white
rectangle trap hung in each tree.

We found that the number of TPBs captured on the traps each week
corresponded very closely to the amount of TPB injury that week.
Thus, in weeks where few TPBs were captured, little new injury had
occurred. In weeks of substantial TPB captures, substantial new
injury had occurred. On the other hand, our counts of TPB numbers
observed directly on the buds or taken in net sweeps bore no relation
to the level of new TPB injury for the week.

Our assessment of the occurrence of TPB injury in this test
was not as accurate as we would have liked, because whenever it
rained, the characteristic droplet of plant sap oozing from the
puncture hole was washed away. In such circumstances, many injured
buds could be discerned only with the aid of a hand lens to reveal
the microscopic puncture. This suggests that in a "normal" Massachu-
setts spring, with rainfall once or twice a week, grower reliance on
visual examination of buds for presence of oozing plant sap as the
sole indicator of TPB injury could be highly misleading. Our experi-
ments indicate that use of the white rectangle traps is a much more
reliable method.

Beginning in 1978, we plan extensive studies to relate numbers
of TPB captured on the white traps to level of TPB injury. Develop-
ment of an accurate trap capture : injury index of TPB should be of
real value to growers in making decisions about the need to apply a
pesticide spray against TPB. But even in the intervening years before
refinement of the index, the white rectangle traps should be useful
to those apple growers having a perennial TPB problem: the traps
will function as a reliable indicator of the first appearance in the
spring of active TPB adults in the orchard. They should also be use-
ful to peach growers for this same purpose.

These white traps, which also effectively serve to monitor sawfly
adult activity, can now be purchased from: New England Insect Traps,
Colrain, Massachusetts 01340.

Cooperative Extension Service

University of Massachusetts

Amherst, Massachusetts

R. S. Whaley

Director

Cooperative Agricultural Extension Worl<;

Acts of May 8 and June 30, 1914

Official Business

Penalty for Private Use, S300.

POSTAGE AND FEES PAID

U.S. DEPARTMENT OF

AGRICULTURE

AGR 101

BULK THIRD CLASS MAIL PERMIT

FRUIT
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 43 (No. 3)
MAY/ JUNE 1978

TABLE OF CONTENTS

Apple Pollination Comments
Pomological Paragraph

Foliage sprays containing nitrogen for fertilizing

peaches
Factors Affecting Shape of Apples and Increasing

Their Length with Promalin*
Nutritional Problems and Suggestions for Fertilization

of Apple Trees in 1978
Naphthaleneacetic Acid(NAA) for Tree Training
Alternate vs. Every Middle Spraying for Apple Pests

in 1977

APPLE POLLINATION COMMENTS

Roger A. Morse
Department of Entomology
Cornell University
Ithaca, N.Y.

To set fruit, apples must be cross-pollinated. Mcintosh pollen
will not grow on a Mcintosh flower's female parts; the pollen must
come from another apple variety. This is true with most apple varie-
ties. Many insects may carry pollen from one apple flower to another
and oftentimes flies, wasps and solitary bees are important in cross-
pollination. When one has only a few acres of fruit, there are
usually enough insects in the vicinity to do the job. In most years,
if eight percent of the flowers on a tree set fruit, one has an
adequate set for a crop.

In larger orchards, those with five, ten or more acres, there
are usually too few insects available to accomplish cross-pollination.
This is especially true in those years when we have cool, cloudy
damp weather during bloom. Large orchards need to have colonies of
bees moved in to insure pollination.

The wholesale price of honey has tripled since 1971. The re-
tail price for a pound of table honey has moved from 45(f to 99(f:
to $1.30. Many beekeepers are reluctant to move bees into orchards
because they fear their colonies may swarm. Swarming weakens a
colony and the beekeeper may lose his honey crop. Beekeepers who are
renting bees for apple pollination are charging more than ever
before and it is important that growers get the most from rented bees.
There are several very simple rules to follow.

Where to Place Colonies

Honey bee colonies should be placed where they receive a
maximum of sunlight. The entrances should face east or south. We
prefer to see colonies on land which has a slight slope to the east
or south. If the colonies have some protection from prevailing
winds, more bees will fly than if they do not. Never place colonies
under trees where they will be shaded. Sunlight warms the hives
and encourages more bees to take flight.

How Large A Colony to Rent

It appears the price for rented colonies in New York State for
apple pollination this year will vary between $15 and $35 per
colony. One must not expect that colonies rented for $15 or less will
contain as many bees as do those which command a higher price.

We recommend that colonies for apple pollination be in at least
two boxes [supers). We recommend the bees have brood in six frames
in each colony. Having brood in six frames is not the same as
having six frames full of brood. A brood nest is more or less the

- 2

shape of a ball. When there are six frames with brood, the outer
frames may not be too full. It is nearly impossible to count the
number of bees in a hive, but one can count the number of frames
which contain brood.

If there is brood in six frames, the colony will contain about
25,000 bees, perhaps more, and be in excellent condition for apple
pollination. Colonies which have brood in six frames at the outset
of bloom may swarm if the bees are kept in the orchards too long.
For this reason, some beekeepers are reluctant to rent colonies
which are this populous.

Colonies Should be Grouped

We recommend that colonies be placed in groups of three to five
within the orchard. By grouping colonies in this manner, the apple
grower can select the better locations for bees, spots where the
colonies will receive a maximum amount of sunlight throughout the
day. This also allows one to select those spots which are drier
and which are protected from the prevailing winds. Again, one wants
to encourage as much flight as possible.

Dry Bottomboards

Colonies of honey bees which have wet bottomboards will send
fewer bees to the field than those which have dry bottomboards.
Wet bottomboards tend to cool the colony and more bees are required
to keep the brood nest warm.

We recommend that apple growers place pallets, old tires,
cinder blocks or slabwood in the orchard on which colonies may be
set. This practice will work to the advantage of both the fruit
grower and the beekeeper.

If the colonies of bees are six to eight inches off the ground,
there will be less problem with grass blocking the entrances and
hindering flight. Grass may prevent the sun's hitting the colony
entrance and delay flight in the morning. A piece of tarpaper
tucked under the front of the colony and extending outwards will
serve to keep the grass from growing and blocking colony entrances.

Dandelions, Yellow Rocket and Apples

Dandelions, yellow rocket and apples all produce nectar which
contains about 40 percent sugar. Thus, all three of these plants
have flowers which are about equally attractive to honeybees.
Dandelions produce more nectar in the morning than they do in the
afternoon and so there will be fewer bees visiting dandelions in
the afternoon. Apples appear to produce nectar about equally all da)
as does yellow rocket. The best way to get rid of dandelions and
yellow rocket is to use a weed killer. Mowing these competing plant!
will help, but it is expensive.

If there are a large number of dandelions and yellow rocket
plants in flower in or near the orchard, one needs additional bees.

At the present time, we have no method o£ discouraging bees from
visiting these weed plants.

Fresh Water

Honey bees use large quantities of water to dilute the honey
which they feed to their young. Bees may collect water from wheel
ruts and depressions in the orchard. These may contain an accumu-
lation of pesticides. If the bees have fresh, clean water, fewer
will die. Beekeepers who rent bees for apple pollination expect to
lose a small number of their bees because of pesticides and they
adjust the rent price of their colonies accordingly. The grower
who provides fresh water for honey bee colonies will benefit.

Hand-Collected Pollen

A small number of apple growers in New York State buy hand-
collected apple pollen, take it to the orchard and play "little Miss
Honey Bee." Hand-collected pollen may be applied to the female
parts of a flower with a brush. Little pollen, if any, gets where
it is needed when it is dropped from an airplane or shot into a tree
from a shotgun shell. While this may be fun, it is a waste of time
and money. There is nothing mysterious about cross-pollination. It
involves the transfer of pollen from one apple variety to another
apple variety.

Honey bees can cross-pollinate apples easily, quickly and at
a reasonable cost if they are given the proper management and if the
orchard is properly interplanted with varieties which have pollen
which will cross-pollinate each other. Neither hand-collected
pollen or pollen moved by bees will grow unless the temperature is
sufficiently high.

Hedgerowing is a Special Problem

Nearly all orchards planted today follow the same scheme. The
apples are grown on dwarf rootstock and planted in hedgerows.

A wind of about 12 miles per hour stops bee flight. A wind of
only a few miles per hour will slow bee flight and oftentimes dis-
courage bees from flying over the tops of hedgerows. We know from
experience that bees prefer to fly up and down the sides of rows.
Planting pollenizing varieties in the row is important because there
must be an exchange of pollen to set fruit.

***************

POMOLOGICAL PARAGRAPH

Foliage sprays containing nitrogen for fertilizing peaches . Peach
trees frequently have small pale green leaves, or yellow leaves
with red flecks that develop into a mild "shothole" condition. These
are symptoms of nitrogen (N) deficiency caused either by cold weather

4 -

in the spring. or by failing to apply N by mid-April. These
symptoms were present in many of our peach orchards in May and
early June of 1977. Some growers asked if urea sprays would bene-
fit growth. Unfortunately, foliar sprays of N to peach trees are
ineffective. Peach leaves do not absorb N as efficiently as do
apple leaves.

***************

FACTORS AFFECTING SHAPE OF APPLES
AND INCREASING THEIR LENGTH WITH PROMALIN*

W.J. Lord and Duane Greene
Department of Plant and Soil Sciences

Shape of apples is known to be influenced by both climatic and
non-climatic factors. The elongated shape and the 5 lobes at the
calyx end of Delicious apples are particularly distinctive; thus,
there is interest in studying the factors influencing their shape
and the possibility of modifying that shape by chemical means.

Climatic Factors

Delicious grown in Massachusetts are longer some years than
others and within a given year their shape will vary considerably
among orchards. Shape of apples depends on cell division and
cell elongation, both of which occur within 3 to 4 weeks after
bloom, and is governed by growth hormones in the tree.

In 1914 J. R. Shaw in Massachusetts reported on the relationship
between shape of Ben Davis and Baldwin apples and the temperature
following bloom; the cooler the temperature, the more elongated
the apple. He concluded that during the post-bloom period, temper-
ature variations between the 6th and 16th day after full bloom
fitted the observed variations in shape more closely than during
any other period.

Non-climatic Factors

As most growers know, distribution of seeds in fruit influences
shape. Apples with small numbers of seeds are frequently lopsided,
with the less fleshy side being the one lacking seeds. M.N.
Westwood and L.T. Blaney, in Oregon, found that rootstocks, crop
density, cluster position, and strain can also influence fruit shape
(Non-climatic factors affecting the shape of apple fruits. Nature
200:802-803, 1963). In studies with Delicious, fruit from trees
on M.l, M.2, M.16 and seedling roots were longer than those harvested
from trees on M.9, M.4 and M.7. Both crop load and fruit location
affected the shape of Golden Delicious. Those from trees with a
light crop (whether the result of heavy thinning or light bloom)
were longer than fruit from trees with a heavy crop. The "king"
fruit were longer than side-bloom fruit. Fruit shape differed
significantly among the 3 Delicious strains studied, with those
from the "regular" Delicious trees being flatter than those from

*Trade Name

Starking and Starkrimson strains.

Fruit Shape Alterated by Growth Regulators

M.W. Williams and E.A. Stahly, in Washington, found that
applications of cytokinins and gibberellins , alone and in com-
bination, to Delicious apples just after full bloom affected fruit
shape by increasing their length. (Effect of cytokinins and
gibberellins on shape of 'Delicious' apple fruits. Jour. Amer. Soc.
Hort. Sci . 94: 17-19, 1969). Cytokinin-treated fruits were longer
than normal with prominent, well-developed calyx lobes, whereas
those treated with gibberellins were merely longer. They postulated
that the influences of temperature, crop size, and fruit location
in the cluster on fruit shape were very likely related to their
effects on the levels of gibberellins, cytokinins and other naturally
occurring growth regulators in the developing fruits.

Fruits can become flatter by application of Alar-85*. Because
of this undesirable response plus possible fruit size suppression
on Delicious we prefer using 2 , 4 , 5 - TP for preharvest crop con-
trol rather than Alar-85. Williams in 1975 (Carry over effect of
ethephon on fruit shape of 'Delicious' apples. HortScience 10: 523-
4) reported that ethephon applied to Delicious apples before harvest
to improve fruit quality also can flatten fruit the following year
if applied to trees of medium to low vigor.

Promalin to Lengthen Delicious

Promalin, a plant growth regulator formulation containing
gibberellins and cytokinin, when tried in several areas of the
United States, has lengthened Delicious apples, increased their
weight, and improved development of the calyx lobes. We have con-
ducted limited tests with Promalin because of grower interest
in increasing the "typiness" of Delicious and the possibility of
increasing yields due to increased volume of the fruit.

In 1975, 1 pint of Promalin/per 100 gallons of water applied
at late petal fall at our Horticultural Research Center did not
increase the "typiness" of Richared Delicious apples. We enlarged
our trials in 1976 and added surface active agents glyodin and
Triton B-1956 to 2 of the treatments (see Table 1 on the next
page).

Fruit set was not influenced by the treatments. However, the
length of the Delicious as indicated by the L/D ratio was increased
by the 1/2 pint of Promalin when applied with glyodin or Triton B-
1956, and also by 1 pint of Promalin; the higher the L/D ratio the
longer the apple -- a "typey" Delicious will have a L/D ratio of
1.00 or greater.

It is of interest to note that although Promalin increased the
length of the Delicious the difference could not be detected by
visual observation before harvest but could be seen on the harvested

*Trade Name

--6

fruit. Furthermore, neither the fruit size nor total yield was
influenced by the treatments (Table 1).

Table 1. Effects of Promalin, applied at 125 gal/A when petals on
king blossoms started to fall, on Richared Delicious apples, 1976.

Treatment
(rate/lOO gals)

Fruit set (per
cm. limb circ)

T/D
ratio^

Fruit
wt (gms)

Yield
(bu/tre

1. Check

2. Promalin, 1/2 pt

3. Promalin, 1/2 pt
+ glyodin, 1 pt

4. Promalin, 1/2 pt
+ Triton, 1/4 pt

5. Promalin, 1 pt

5. 3a
6.0a

5. Oa

5.7a

6. 6a

0.98b

190ab

12.2a

0.99ab

175c

13.6a

1.01a

1.01a
1.02a

195a

185abc
ISlbc

13.8a

14.8a
15.2a

^L/D = Length/diameter ratio

A trial was also conducted in a grower's orchard in 1976,
with 1/2 pint or 1 pint of Promalin applied when the petals on the
"king" blossoms on Starkrimson Delicious started to fall. The
results were similar to those reported in Table 1. Measurements of
the L/D ratios of the harvested fruit indicated that the Promalin-
treated fruit were longer than those from the check trees, but this
increase in length was not evident by visual observations of the
fruit while on the tree nor was there any significant increase in
fruit weight or yield.

In 1977, Promalin at 1 pint per 100 gallons of water plus 1
pint of glyodin was applied at full bloom or calyx of Starkrimson
Delicious at the rate of approximately 150 gallons per acre. The
full bloom application was not effective whereas the fruit from
trees sprayed at calyx were heavier and longer. However, the
difference as in 1976 was too slight to be noticeable on the tree.

Summary

Both climatic and non-climatic factors can influence the "typi-
ness" of Delicious apples. Our most-typey Delicious are produced in
orchards on high elevations where post-bloom temperatures are apt to
be cooler than at lower elevations. However, temperatures are not

always favorable even at higher elevations and there are growers
interested in giving "mother nature" a boost by using Promalin.
Our trials with Promalin are very limited and more work is needed
to determine the influences of temperature. However, it does
appear that a consistent favorable response from a Promalin spray
may not be likely.

A number of growers purchased Promalin last year but for one
reason or another did not apply it. We certainly do not want to
discourage Promalin use in 1978 because we need to determine its
possible usefulness under our conditions.

Our only suggestions concerning Promalin use other than
following the directions on the label are to add to the spray mix-
ture a surface active agent such as glyodin and to apply on a day
when temperatures are 60° or higher.

***************

NUTRITIONAL PROBLEMS AND SUGGESTIONS FOR
FERTILIZATION OF APPLE TREES IN 1978''-

W.J. Lord and Mack Drake
Department of Plant and Soil Sciences

It should be recognized from the start that it is not possible
to give specific suggestions for fertilization in an article of this
nature. Therefore, the suggestions below merely serve as a guide to
the fruit grower for determining the fertilizer program in his orchard,
It is well to remember that foliar applications are merely supnle-
ments to soil applications.

Nitrogen (N) : The trees severely winter injured in 1976 did
not recover as well as hoped in 1977 in spite of the supplemental
urea sprays. Some of these trees probably should receive an urea
spray (5 pounds/lOn gallons) at about first cover in May. Apply
as a separate application.

Most orchards had only a medium-sized crop in 1977 while some
blocks of Delicious either had no crop or a light crop due to frost.
Trees which had no crop, or just a partial crop, in 1977 should
receive little or no N in 1978. To the contrary, trees that had a
large crop in 1977 may be low in available N for utilization this
spring.

The best guide to N needs of your trees is leaf analysis
combined with observations of tree vigor, fruit set, and fruit

■^Unless stated otherwise all photographs are by Louis Musante, Audio
Visual Dept. University of Massachusetts.

8 -

color. Growers definitely are using less N on Mcintosh than in
the past because we need medium-sized, well-colored apples with long
storage life. Some growers have not omitted N in mature Mcintosh
blocks for 5 to 8 years with no apparent harmful effects.

Apply sufficient N to keep bearing Delicious trees vigorous.
N levels of 2.2 - 2.41 in bearing Delicious trees areprobably sat-
isfactory because it is necessary to keep the tree vigorous in order
to produce large-sized fruits. Furthermore, obtaining sufficient red
color on the newer strains of Delicious is not a problem.

Potassium (K) : The K requirements of apple trees with a large
crop are high because the fruit utilizes about 3 times as much K as
N. Since the quantity of K stored by the tree is extremely small,
it seems important to supply adequate K this spring on trees that
had heavy fruit set in 1977.

The requirements of apple trees for K (expressed as K2O) based
on potential yields are as follows: (a) less than 15 bu : 1.3 lbs/
tree; (b) 15 to 25 bu : 1.3-2.7 lbs/tree; and (c) more than 25 bu:
2.7-4.3 lbs/tree. It is necessary, however, to maintain a balance
among the essential nutrients for apple trees. For example, exces-
sive levels of K can reduce both leaf and fruit Ca. Therefore, we
strongly urge that you participate in our leaf analysis program to
more accurately determine the K needs of your apple trees^

Calcium (Ca) : Cork spot and bitter pit, which are visual
evidence of low Ca levels in apples, was more prevalent than usual
on Delicious during the 1977-78 storage season.

The Delicious on the left in the following photograph shows
bitter pit and the one on the right has cork spot. Bitter pit is most
frequently associated with the calyx end of the apple and its severity

- 9 -

(Photograph by Russell Mariz, Photo
Center, UMass. )

will increase in storage. Cork spot is not localized and will appear
anywhere on the apple. The spots are more pronounced than bitter
pit, being much deeper and wider. In some cases the cork spot resem-
bles the inner cone of a miniature volcano, with the depressed skin
area containing green or dark red pigment. Cork spot does not increase
in severity in storage.

Cortland continued to be troublesome in some orchards because o£
its susceptability to bitter pit, and a few orchardists were concerned
this fall about this disorder on Mcintosh.

It is very difficult to increase Ca content of apple trees
and fruit. Although foliar sprays of Ca solutions have been shown
to reduce bitter pit, they have not eliminated it. A major problem
is that Ca in the soil moves very slowly into the tree and most
of it is quickly tied up in an insoluble form. We suggest the
following measures to increase Ca content of apple leaves and fruits.

A. Continue to apply 3 tons of limestone per acre every 2
to 3 years. Where high magnesium lime was used in the last
application, the use of a more soluble high Ca, low Mg lime
(5-71 MgO) will act more rapidly and will provide more Ca.

B. Use calcium nitrate as the source of nitrogenous ferti-
lizer. Calcium nitrate increases the level of soluble soil
Ca more quickly, increases the downward movement of Ca and
raises the pH of the soil.

C. Apply foliar sprays of calcium chloride (CaCl2) starting
about 3 weeks after petal fall and repeat at 2-week inter-
vals, totalling 6 to 8 applications. Apply 6 to 8 pounds
CaCl2/acre/spray until mid-July. After mid-July, apply

10 pounds/acre/spray. Sprays may be applied dilute or on a
trial basis up to 6X concentration. Growers desiring to
paCl2 with their cover sprays should do it on a tri al
When combining with cover sprays , add CaCl2 last to

com bine
ba sis
the

only,

spray

- in

tank. If weather conditions permit going over 14 days without
a cover spray, use CaCl2 spray alone. CAUTION : DURING DROUGHT
DO NOT APPLY A SECOND FOLIAR CaCl2 APPLICATION UNTIL AN INCH
OR MORE OR RAIN FALLS. Do not mix CaCl2 and Solubor* in sprays,

Foliar injury usually is worse on Mcintosh than Delicious.
There is some evidence that the combination o£ guthion and
CaCl2 may increase foliar burn. Foliar injury was more severe
from dilute sprays than when applied at 6X at the Horticultural
Research Center in 1976 but the opposite occurred in 1977. This
appears to indicate the CaCl2 injury varies with season because
of such factors as rainfall and temperature.

Magnesium (Mg) : Deficiency symptoms of Mg (Figure 2) are not
as prevalent as in the past but this important element should not
be forgotten in our anxiety to increase Ca levels.

Pictu

f icie

the s

Defic

ized

tween

leave

usual

seaso

toms

By la

which

may b

leave

defic

at ha

red on the
ncy symptom
ymptoms on
iency sympt
by necrotic

the veins,
s on shoots
ly affected
n progresse
appear on t
te summer,

the leaves
e defoliate
s near thei
iency incre
rvest .

left is Mg
s on pear
apple are
oms are ch

(brown) a
The olde

and spurs

first, an
s the inju
he younger
the shoots

show Mg d
d except f
r terminal
ases fruit

de-
leaves ;
similar,
aracter-
reas be-
r, basal

are
d as the
ry symp-

leaves.

on
ef iciency
or a few
s. Mg

drop

gram.

Mg def

condit

gallon

sprays

should

apply

The requirements of trees for
Mg can best be met by maintaining
an adequate dolomitic liming pro-
Since it takes years before lime is effective in correcting
iciency, Epsom salt sprays can be used to help correct the
ion. Apply 2 to 3 sprays at the rate of 15 to 20 lbs per 100
s of water at the time of calyx, first cover and second cover
To avoid possible incompatibilities, the Epsom salt sprays
not be combined with the regular pesticide sprays. Don't

Epsom salts or a lime high in Mg unless leaf analysis or visual

observation indicates low Mg levels. Mg can supress Ca ;

Boron (B) : Toxicity symptoms of this element were observed in
a few orchards in 1977. They occurred on bearing trees sprayed
with a foliar application of B and on trees fertilized with B the
year of planting. The picture on the following page shows typical
foliar symptoms of B toxicity. The symptoms are characterized
by loss of chlorophyll (green coloration) from along the midrib
and larger lateral veins. The symptoms are first apparent at the

*Trade Name

11 -

base of the leaf blade. In severe cases,
loss of chlorophyll is more extensive than
shown in the picture; marginal leaf scorch
develops, leaves absciss, and wood injury
can occur.

B def
toxicity,
deficiency
characteri
shaped les
The dead c
corky befo
the disord
(particula
open calyx
they matur
first reco
cessive pr

iciency is more common than B
The most common symptom of B
is found in the fruit being
zed by brown, round or irregular
ions of about 1/4 inch diameter,
ell masses become dry, hard and
re harvest. Fruit affected with
er will have a pebbled surface
rly noticeable on Cortland) ,
and abnormally dark color as
However, frequently the
gnition of the problem is ex-
eharvest drop.

B can be supplied to apple trees either by foliar or soil
applications. Use the most economical and convenient method.
However, it is safest to apply all elements as a fertilizer except
m emergency situations .

Soil applications of boron should be applied to orchards
every 3 years. The rates of application per tree vary with tree
age and size. In low density orchards, apply 1/4 pound of borax
(11.11 actual B) or its equivalent under young trees coming into
bearing , 1/2 to 3/4 pound to medium age and size trees and 3/4 to
1 pound to large or mature trees. Be sure to note the percent
actual B in the fertilizer being used to supply this element" ! B
containing fertilizers vary from approximately 11 to 21% actual B.

In medium and high density orchards (115 trees/acre or higher),
it might be best to apply B on an acre basis. We suggest the fol-
lowing rates per acre of borax (11.1% actual B) or its equivalent:
(a) trees 4 to 7 years of age - 12 lbs; (b) trees 8 to 15 years of
age - 12 to 24 lbs; and (c) trees 16 to 30 years of age - 24 to
48 lbs.

When the soil application of B is followed by a wet spring,
it may be advisable to apply 2 foliar applications of B the
following year.

Many growers now rely on annual foliar applications of B.
The usual practice is to add Solubor to the first 2 cover sprays.
Fertilizer grades of borax may contain grit and should not be used
in a sprayer. Mature trees should receive 4 pounds of Solubor per
acre each year. Consequently, the goal is to apply about 2 pounds

per acre in each of the 2 applications. For young orchards, the
addition of 1/2 pound of Solubor per 100 gallons (dilute basis)
to the first 2 cover sprays meets the B requirement of these trees.
Reports of New York State indicate that sprays can be concentrated
up to 8X with satisfactory results.

Leaf samples from orchards treated with Solubor have indi -
cated adequate leaf boron levels but the fruit was deficient in
this element . Whether or not B applied as a fertilizer more ade-
quately meets the B requirement of apples than foliar-applied
B is not known by us.

Manganese (Mn) : The element was deficient in several orchards
last summer . As sEown in the photograph below apple leaves having
Mn deficiency have interveinal fading of chlorophyll with the veins
remaining green. In the past we have analyzed Mcintosh apple leaves
from trees showing Mn deficiency and found the leaf of this element

to be 9 to 14 ppm. Mn levels of th
are critically low in comparison to
standard of 50-100 ppm set by othe
apple trees. Mn deficiency should
on trees showing considerable folia
Although we haven't definite proof,
ciency appeared to be associated wi
fruit drop on a few trees in one or
1977. Mn deficiency can be correct
applications of manganese sulfate o
fungicide containing Mn. Apply man
sulfate at about first cover at the
lbs per 100 gallons of water. If u
containing fungicide, 2 or 3 applic
necessary with timings about petal
and second cover.

is magnitude
the desired
r states for
be corrected
ge damage.

Mn defi-
th excessive
chard in
ed by foliar
r of a
ganese

rate of 3
sing a Mn-
ations are
fall, first

Mn toxicity is implicated with the problem of "apple measles"
shown in the photograph on the following page. The twig from
Delicious at the top of the photograph shows severe symptoms of
measles while the twig below has normal bark. Measles can severely
injure or kill young Delicious trees. An over-application of a
dormant-oil spray can induce symptoms similar to that shown in
the photograph.

Our only solution to the apple measle problem is raising
the soil pH to 6.0-6.5. Apply lime, if needed, before planting
and add 2-3 lbs of lime to the planting hole.

13 -

Zinc (Zn) : Based on optimum levels of Zn established by some
states, some of our orchards are low in this element. Massachu-
setts growers have not used zinc sulfate sprays applied at the
'•green tip" stage of bud development to increase zinc levels but
some use manganese-zinc containing fungicides. These appear to
be increasing Zn levels in our orchards.

NAPHTHALENEACETIC ACID (NAA) FOR TREE TRAINING

William J. Lord and Joseph Sincuk
Department of Plant and Soil Sciences

It was reported in
excellent tree training
the stem of newly-plant
second, third, and four
cut, which was not pain
treatment eliminated th
the trees which compete
number of favorably pos
and improved crotch ang
the bud selected for th
reportedly developed fr
suggested NAA treatment
procedures which involv
is in competition with

1977 that II NAA in latex paint is an

aid when applied as a painted band around
ed apple trees (after heading) to cover the
th buds. The first bud below the heading
ted, became a vigorous central leader. This
e cluster of vigorous shoots in the top of

with the central leader and increase the
itioned branches on the newly-planted trees,
les of these branches. If for some reason
e central leader died, a strong leader
om the NAA-treated area. Basically, the

is a replacement for the current training
e removal by hand, in June, of growth that
the shoot favored as a central leader.

Directions for use indicated that the II NAA in latex paint
should be applied after heading the newly-planted tree to the

desired height but before growth begins,
effective if made after start of growth.

The treatment is not

Last summer, we compared the NAA tree training technique on
Marshall Mcintosh, Macoun, and Redspur Delicious with removal of
buds 2, 3, and 4 immediately after planting (disbudding) or removal
of shoots competing with the central leader in mid-June. The
Marshall Mcintosh and Redspur Delicious were headed at 36 and 30
inches, and the Macouns at 30 inch height. All treatments were
replicated at least 16 times.

The NAA treatment was a complete disaster in the 3 orchards.
The first bud below the heading cut, which was supposed to develop
into the leader, was with only one exception either severely stunted
or killed. When the bud selected for the central leader died, no
strong leader developed from the NAA-treated area.

Crotch angles were affected only on the Redspur Delicious
(Table 1) . The trees receiving the NAA treatment and those on
which the competing shoots were removed in mid-June, had wider
crotch angles than the disbudded trees for each heading height.

Table 1. Effect of NAA application, removal of competing shoots
in mid- June, and disbudding on crotch angles.

Treatment and
heading height

NAA, 36 in
NAA, 30 in
Shoots removed, 36
Shoots removed, 30
Disbudding, 36 in
Disbudding, 30 in

m
in

Cultivar

Marshall

Redspur

Mcintosh

Delicious

Macoun

Avg. crot

ch angle (deg

rees) ^

70a

60a

67a

53bc

60a

69a

56ab

68a

56ab

59a

66a

50c

67a

44d

55a

Mean separation in columns by Duncan's multiple range test, 5%
level.

We do not know why the results with NAA were so unfavorable
although we believe the concentration was too high. However, it
is obvious that Massachusetts growers should not use NAA for tree
training until further experimentation shows the procedure to be
reliable.

Even if the NAA tree-training technique is proven to be reli-
able, it has at least 3 obvious drawbacks. Spring is an extremely
busy season and chances are great that the NAA will not be applied,
Secondly, the treatment must be applied before growth starts. And
lastly, frequently a better choice of a leader can be made in mid-
June and this job can be combined with limb spreading with clothes

pins. Thus, at present, we still suggest the standard procedures
of leader selection. This involves selection of the uppermost
shoot on the windward side of the newly-planted tree when shoot
growth is 6 to 8 inches in length. Shoots competing with the
selected leader should be rubbed or pruned off for a distance of
approximately 6 inches down the stem..

***************

ALTERNATE VS. EVERY MIDDLE SPRAYING FOR APPLE PESTS IN 1977

R.J. Prokopy, R.G. Hislop, and K.I. Hauschild
Department of Entomology
and R.L. Christensen
Department of Agricultural and Food Economics

Earlier, we reported our 1976 findings on the comparative
effectiveness of alternate vs. every middle spray treatments in 3
commercial orchards (see Fruit Notes 42(5):8-10). In this article,
we report on our 1977 findings , and include a cost-benefit treat-
ment comparison for one of the orchards.

The alternate middle treatment involves spraying alternate
halves of each tree on alternate spray dates instead of both
halves on all spray dates. For example, in applying the first
cover spray, the sprayer would be driven up the middle between
tree rows A and B and return down the middle between rows C and
D, skipping the middle between rows B and C. For the second cover
spray, the sprayer would be driven up the middle between rows B
and C, down the middle between rows D and E, and so forth. If
this pattern were followed with every spray application, it would
save 50% of the spray material costs.

In 1977, we compared alternate with every middle spray treat-
ments in the same 4-acre blocks in the same 3 orchards as in 1976.
Each block was divided into 2 plots : one receiving the alternate
middle program on each spray date from pink (or petal fall) through
last cover; the other receiving the every middle program. Each
grower used an air blast sprayer at 4X. He followed his normal
spray schedule, and used his own selection of pesticides. All
trees were full grown - some on M. 7 rootstock, others on standard.
The centers of the trees were fairly well pruned in all blocks.

To determine the extent of pest pressure, we hung traps in
each plot for monitoring tarnished plant bug adults, codling moth
and redbanded leafroller adults, and apple maggot flies (see Fruit
Notes 41(1) : 3-4; 41(6) :6-9; and 43(2):10-14 for information on
construction of each trap type) . We caught the following average
numbers/trap in each plot:

Tarnished Plant Zoecon phero- Apple maggot

Bug Trap mone traps trap

(unbaited white Codling Redbanded (unbaited

Treatment Orchard rectangles) Moth leafroller red sphere)

Every
middle

A
B

Average

Alternate
middle

A
B

Average

1.3

5.0

5.7
4.0

1.0

13.0

9.3

7.8

110

120

127

205

145

185

111

157

151

7.0

3.0

5.7
5.2

2.7

14.5

11.7
9.7

Researchers in New York believe that when cumulative codling
moth captures/trap reach 15-20 and apple maggot captures/trap reach
1, fruit injury is likely to occur unless insecticide is applied.
A relation between plant bug or leafroller captures and need for
spraying has not yet been established, but substantial numbers of
each were trapped. Overall, the trap data show that pest pressure
was considerable in both the every and alternate middle plots.

To determine the actual amount of fruit injury caused by these
and other pests and to determine spider mite and aphid abundance
on leaves, we examined 60 fruits and 60 leaves/tree on each of 6
trees in each plot in each block every 3 weeks from mid-April
until harvest. The results are given here:

- 17

Spraying every middle Spraying alternate middles
in orchard: in orchard:

Avg.

% leaves
infested with:

Mites

6.0

15.2

6.1

9.1

20.6

16.7

2.1

13.1

Aphids

1.7

2.9

2.2

2.6

0.8

3.2

1.3

1.8

% fruit
injured by:

Plant bug

0.3

1.9

1.3

1.2

0.3

2.9

1.5

1.6

Curculio

0.4

0.1

0.2

1.2

0.3

0.6

Sawfly

0.1

0.3

0.1

0.6

0.1

0.2

Green
Fruitworm

0.1

0.3

0.1

All other
insects

Total 1977

0.3

2.6

1.7

1.5

0.5

5.1

2.0

2.5

Total 1976

0.9

5.8

1.6

2.8

1.7

5.2

1.9

2.9

The results show that for all orchards combined, an average of
1.51 of the fruit in the every middle plots was injured by insects
vs. 2.51 fruit injury in the alternate middle plots. Compared with
1976, the 1977 results show 141 less fruit injury in the alternate
middle plots and 46% less in the every middle plots. Most of the
1977 difference between alternate and every middle plots was attri-
butable to Orchard B, where the presence of abandoned trees nearer
the alternate middle plot resulted in heavier insect pressure on
that plot.

As in 1976, plant bugs caused the most fruit injury. Their
damage was slightly greater in the alternate than every middle
treatment. However, because plant bug damage on a ripe fruit
appears as a purely cosmetic injury, and does not affect the eating
quality of the fruit, most growers cull only about 50% of plant
bug injured fruits. The next most injurious insect was plum cur-
culio. It was the only fruit insect to cause greater injury in
the alternate middle than the every middle plot in each orchard.
Apple sawfly and green fruitworm caused slight injury, while no
fruits in any plots were found damaged by codling moth, apple maggot,
or redbanded leafroller.

In contrast to 1976, aphids were, on the average, slightly
more abundant in the every middle than alternate middle plots. As

- 18 -

in 1976, spider mites were, on the average, slightly more abundant
in the alternate middle than every middle plots.

Some apple scab was observed in each block, but did not appear
to occur in any greater amount in the alternate middle plots.

A cost-benefit analysis of the every vs. alternate middle
treatments in Orchard C was conducted by students in a graduate
insect pest management class at UMASS (see Fruit Notes 43(2) :3-7).
The results are summarized here:

Dollar Costs/Acre

Every Alternate
Middle Middle Difference

Spray materials* 135.70 67.85 -67.85

Labor (at $3/hr) 10.50 5.25 - 5.25

Fuel, oil, filters,
etc. 5.00 2.50 - 2.50

Value of fruit loss

owing to insect 5

disease injury** 32.72 44.72 +12.00

Cost reduction from

alternate middle

program*** -63.60

(Since a reduction in net costs is the same as an increase
in returns, the value of $63.60 should be regarded as an
increase in net returns.)

* Includes cost of all insecticide, miticide, and fungicide
materials.

** Fruit yield was sampled on randomly selected trees and found
to be equal in the alternate and every middle plots. Total
yield estimated at 750 bushels/acre in each plot. Only 0.181
and 0.06% diseased fruits appeared in the 3360 fruits sampled
at harvest in the alternate and every middle plots, respectively
Fifty percent of the fruits injured by plant bugs plus all
fruits injured by other insects were considered as culls. Total

bushels of culls per acre were 8.18 and 11.18 for the every and
alternate middle plots, respectively. Culls were given an
average value of $2/bushel (combination of #2 fruit and cider j
apples). All undamaged fruit was given a value of $6/bushel. '

The analysis does not include possible additional costs (if
any) of grading out the greater number of insect- and disease-
injured fruits (11.18 - 8.18 = 3.0 bushels/acre) from the
alternate middle plots.

***

- 19 -

The results show that grower C realized a net profit of
$63.60 more per acre from the alternate middle than the every
middle plot. An additional benefit was that the grower could
spray the alternate middle plot in about half the time as the
every middle plot. This allowed him to respond more rapidly to
conditions calling for immediate pesticide application.

We conclude from our first 2 years of experimentation that
an alternate middle spray program in Massachusetts shows promise
of effectively controlling most of the major insect pests that
attack the fruit. To date, it has proven just as effective as an
every middle program against those pests which are highly mobile,
and hence make frequent contact with the sprayed portion of the
tree: codling moth, redbanded leafroller, and apple maggot. In
some situations, the alternate middle program may be slightly less
effective against a pest like plum curculio, whose mobility within
the tree is quite restricted (see Fruit Notes 42(4) :5-7). Where
such is the case, every middle treatments for the petal fall and
first cover sprays would be advisable. The alternate middle pro-
gram's effectiveness against spider mites and aphids may depend on
the type of pesticides employed. On the one hand, spider mites
and aphids are not very mobile. On the other hand, if not killed
by toxic orchard pesticides, predators are capable of effectively
suppressing spider mites and aphids below damaging levels (see
Fruit Notes 42(2) : 5-7 and 42(6) : 6-10) .

In summary, our findings to date show that the alternate
middle spray program can result in greatly reduced pesticide usage,
effective pest control, and a greater net profit to the grower.
For those growers interested in trying out the program, we would
suggest starting with a one or two-acre block to see how the pro-
gram works with your particular type of sprayer and trees, and
under your particular local insect, mite, and disease conditions.
We would advise against submitting large acreage to this program
until you (and we) learn more about the program's long-term effec-
tiveness and possible shortcomings. For example, we need much
more information on its effectiveness against plum curculio and
apple diseases. Present knowledge suggests that the program works
best where the trees are well pruned (open centers) and spaced at
recommended intervals (not wider) .

Cooperative Extension Service

University of Massachusetts

Amherst, Massachusetts

R. S. Whaley

Director

Cooperative Agricultural Extension Work

Acts of May 8 and June 30, 1914

Official Business

Penalty for Private Use, $300.

POSTAGE AND FEES PAID

U.S. DEPARTMENT OF

AGRICULTURE

AGR 101

BULK THIRD CLASS MAIL PERMIT

FRUITpr
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol 43. (No. 4)
JULY/AUGUST 1978

TABLE OF CONTENTS

Factors Affecting Nutrient Content of Apple Foliage
Pomological Paragraph

Use of ethephon to promote color and ripening of

apples in Massachusetts
Late Summer Fertilization of Strawberries
New Herbicide for Blueberries
Pomological Paragraph

When can the severity of russet on Golden Delicious

be estimated?
Use of Creosote to Prevent Deer Damage in Orchards
Influence of Pesticides on Spider Mite and Predator

Abundance in Massachusetts Apple Orchards —

1977 Results
Apple Tree Response to Summer Pruning
The Effect of Summer Pruning of Mcintosh Apple Trees on

the Calcium Nutrition and Postharvest Quality of the

Apples

FACTORS AFFECTING NUTRIENT CONTENT OF APPLE FOLIAGE

William J. Lord
Department of Plant and Soil Sciences

Crop size can have a considerable effect on the quantity of
several elements in apple foliage. Leaves from a tree with a large
crop will contain more nitrogen (N) and less potassium (K) than
leaves from a tree with a light crop. Leaves from a light-crop
tree may contain 0,2 to 0,3% less N than when the same tree has a
full crop. Leaves may decline as much as 0.41 K in a heavy-crop
year. Calcium (Ca) follows the same trend as N and exhibits about
the same difference as N in leaf content between the light- and
heavy-crop years. Leaf magnesium (Mg) is slightly higher in a
heavy-crop than in a light-crop year. Crop size has little, if
any, effect on leaf phosphorus (P) .

The amount of one element may affect the amounts of other
elements in the leaf. For example, leaves which are relatively
high in N tend to have lower levels of K and P and higher levels
of Mg and Ca than leaves from trees which have a low to medium
level of N. High levels of K may depress leaf Mg and Ca, particu-
larly if the soil supply of Mg and Ca are low. However, moderate
levels of K do not seriously depress Mg as long as there is an
adequate level of Mg .

Another factor which may influence the leaf content of some
elements is soil moisture or rainfall. Leaf K is generally lower
in dry growing seasons than in years with adequate soil moisture.
Mg is generally lower in years which have above normal rainfall
during the early part of the growing season. The magnitude of the
change in leaf content caused by seasonal rainfall will depend
upon the relative wetness or dryness of the season and the supply
of nutrients in the soil. If the soil is so wet or so dry that
development of new roots is prevented, the leaf content of essen-
tial elements could be reduced.

****************

POMOLOGICAL PARAGRAPH

Use of ethephon to promote color and ripening of apples in Massa-
chusett~s^ Our suggestions for use of ethephon for promoting uni-
form ripening and red color of apples have not changed from last
year. These suggestions were published in Fruit Notes 40 (No. 4):
July/August, 1975. Those who do not keep back issues of Fruit
Notes can obtain a copy of the suggestions on ethephon usage from
your Regional Fruit Specialist.

****************

LATE SUMMER FERTILIZATION OF STRAWBERRIES

William J . Lord
Department of Plant and Soil Sciences

In Massachusetts, the June-bearing varieties o£ strawberries
initiate their flower buds in the fall. If conditions are favor-
able, many varieties produce several flower buds in each strawberry
crown and consequently produce several inflorescences per plant.
The extent of flower bud development seems to be influenced by the
supply of available nutrients, particularly nitrogen.

A number of experiments have indicated an advantage of build-
ing up the nitrogen supply in the fall from the standpoint of
increased flower bud formation. However, factors such as earliness
of runner plant rooting, quality of plants, soil moisture, and
pest and weed control may have more effect on plant productivity
than the fertilizer applications.

A recent study in Minnesota showed that nutrition can affect
winter-hardiness of 'Redcoat' strawberry plants. In this study
'Redcoat' strawberry plants deficient in nitrates, phosphorous,
and potassium received fertilizer treatments in late-August. Arti-
ficial freezing tests were conducted on the plants at the onset of
their acclimation to cold weather, and in mid-winter with fully
hardened plants. Plants fertilized with a complete fertilizer of
1:1:1; 2:2:2, 1:1:2, or 1:2:1 ratio made better recovery from the
early and m.id- season artificial freezing tests than the non-
fertilized plants and those that received a fertilizer with a
1:0:0, 2:0:0 or 1:1:4 ratio.

Winter injury to strawberry plants is of frequent occurrence
in Massachusetts, thus it may be worthwhile to fall fertilize* with
a complete fertilizer rather than one containing nitrogen alone,
as has been suggested in the past if the plants lack vigor. We
suggest applying a complete fertilizer (1:1:1, 1:1:2, or 1:2:1
ratio) at the rate of 30 pounds of actual nitrogen per acre.

A broadcast application of fertilizer at that time may damage
the foliage unless precautions are taken. Apply on a clear day
of low humidity and shake off any fertilizer adhering to the
leaves, (a switch made from brush is convenient) or apply during
a rain, to avoid burning of the foliage.

About late August.

****************

NEW HERBICIDE FOR BLUEBERRIES

Dominic A. Marini
Southeast Regional Fruit 5 Vegetable Specialist

Terbacil (Sinbar*) is now registered for the control o£ many-
annual and some perennial weeds in blueberries, and is included in
the 1978 Weed Control Guide for Small Fruits. Some of the weeds
mentioned on the label are crabgrass, fall panicum, foxtail, mus-
tard, yellow rocket, purslane, ragweed, lambs quarters, chickweed,
shepherdspurse, marestail, cinquefoil, hawkweed and quackgrass -
also known as doggrass or witchgrass. As with other new materials,
limited applications on a trial basis are suggested.

Terbacil is sold as a wettable powder that is mixed with water
and applied as a spray. Continuous agitation is necessary to keep
it in suspension for uniform application. It may be applied as
a band along the row and under the bushes or as a complete broad-
cast application.

Plants should be established for at least one year before
being treated with terbacil. It may be applied in the spring or
after harvest in the fall before weeds emerge, or to weeds in the
early seedling stage of growth. Apply at the rate of 2 pounds of
the 80 percent wettable powder per acre on light soils, and 3 to
4 pounds on heavy soils. Do not use on gravelly soils with less
than 1 percent organic matter or where roots are exposed. Avoid
contact of fruit or foliage with spray or mist.

Blueberries may be planted in soil treated with Sinbar one
year after the last application. Do no replant to other crops for
2 years, or injury may result.

* Trade Name

****************

POMOLOGICAL PARAGRAPH

^Tien can the severity of russet on Golden Delicious be estimated ?
Dr .~L'. L"! Creasy, Cornell University, Ithaca, New York, reported
at the 122nd Annual Meeting of the New York State Horticultural
Society that russet on Golden Delicious apples is present 30 days
after petal fall, but the high pigment concentration on the fruit
at this time makes it difficult to see. However, generally by
mid-July russet is readily visible and the amount estimated at
this time will not change through harvest.

****************

•4-

USE OF CREOSOTE TO PREVENT DEER DAMAGE IN ORCHARDS

G. Everett Wilder
Regional Fruit Agent
1499 Memorial Avenue
West Springfield, MA 01089

The white- tailed deer is highly prized by hunters who spend
large sums of money annually in quest of "their" deer. However,
the "Buck-law" in Massachusetts, enacted to increase deer popu-
lation, has not found favor with farmers because deer feed on
agricultural crops.

Deer favor fruit trees, especially apples, as a food source
and cause considerable damage in some Massachusetts orchards. Both
the female and male deer feed on apple trees during the winter
months and the male deer injures trees with his horns. During the
sumjner, deer feed on new shoot growth and developing fruit.

Fencing, the most effective means of keeping deer out of
orchards, is expensive. Therefore, many growers use taste repel-
lents to prevent deer damage. These are somewhat effective when
sprayed on trees during the growing season and/or during the fall
and winter months. Smell and noise repellents also have been tried
in Massachusetts with limited success. Recently, it has been
reported from Maryland that Tabasco Sauce is an effective taste
repellent against deer and rodents.

Ben Tarnauskas, who operates an orchard on the Granville-
Westfield town line, conceived the idea of using creosote as a
deer repellent. Strips of felt approximately 3/4" x 6", with a
wire attached to each strip, were dipped in creosote. (Felt
weather stripping is an available and perhaps the most economical
source of felt.) Ben attached one treated strip per tree on trees
next to the woods. He observed that the deer avoided these trees
and therefore he placed the creosote-treated strips in all young
trees. The creosote has proved to be an effective repellent.

Other orchardists in Granville are now using creosote-treated
felt strips in their orchards. Edward Roberts has placed 2000
strips near young trees (one strip/tree 30 inches above the ground)
with excellent results. No feeding by deer has occurred in trees
containing the strips this past year. Mr. Roberts retreats the
strips with creosote in an oil can. He suggests "touching-up" the
strips about every 3 weeks during the rainy periods of the growing
season. (Once seems enough for the entire winter) . This method
saves on repellent and keeps the odor strong. One caution : creo-
sote will burn apple tree leaves and bark. Therefore, the felt
strip must be hung in such a manner that the excess creosote will
not drip on foliage or wood. A safer method is to drive a 3/4-
inch stick approximately 36 inches in length in the ground near
the tree with the creosote strip wired to its top.

****************

INFLUENCE OF PESTICIDES ON SPIDER MITE
AND PREDATOP ABUNDANCE IN MASSACHUSETTS
APPLE ORCHARDS--1977 RESULTS

Robert G. Hislop, Charles Acker, and Ronald J. Prokopy
Department of Entomology, Fernald Hall

In the March- April, 1977, issue of Fruit Notes we described
the results of our 1976 research aimed at reduced spraying for
spider mites in Massachusetts apple orchards. In 1977, we contin-
ued our search for natural enemies of mites and discovered that
Amblyseius fallacis , our most important mite predator, was even
more abundant and widespread than our 1976 survey suggested. Here,
we discuss the results of our 1977 field work aimed at enhancing
the buildup of this valuable predator in our orchards.

In June, 1977, we resumed the extensive spider mite (red mite
and two-spotted mites) and predator sampling program begun in 1976
but concentrated on sampling only apple tree foliage. We sampled
4 commercial orchards (A, B, C, and D) , located in 2 separate regions
of the state, and 1 abandoned orchard. Two of the commercial
orchards employed one type of spray program, the other 2, a differ-
ent program. In addition, at the Horticultural Research Center at
Belchertown, we applied either Imidan, Guthion, Zolone, or Benlate
at biweekly intervals from petalfall to late August to 3 groups of
trees, with 3 groups left unsprayed for comparison. All trees in
the commercial and Belchertown orchards were sampled at biweekly
intervals to determine spider mite and predator populations. The
samples were collected, processed, and analyzed in the manner
described in the 1977 issue of Fruit Notes .

Results in 1977 supported the 1976 results in that A. fallacis
was common only in certain commercial orchards. In the abandoned
orchard its numbers were low but numerous other predator species
kept red mites and two-spotted mites at very low levels.

In commercial orchards A and B, sprayed with combinations of
Guthion, Zolone, Imidan, Benlate, Glyodin, and Captan, two-spotted
mites reached 10.7 and 14.3 mites per leaf at peak abundance
(Table 1) but red mites remained below damaging levels. Popula-
tions of A_^ fallacis reached maximum levels of only 0.06 and 0.04
mites per leaT'.

On the other hand, in commercial orchards C and D, sprayed
with combinations of Guthion, Captan, and Cyprex, two-spotted
mites were virtually absent. In orchard C, red mites remained
at very low levels, in contrast to orchard D, where they reached
a peak abundance of 36 mites per leaf (Table 1) . A. fallacis was
relatively scarce in orchard C in comparison to orchard D, probably
due to the low spider mite populations. In orchard D, predacious
mites reached very high numbers, (5.4 mites per at peak abundance)
but yet were unable to control the red mites. In addition to the
large A_^ fallacis populations in orchard D, there were 2 additional

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species of mite predators, called yellow mites, that are very slow
and inefficient at locating and capturing red mite prey. These
predators were considerably more abundant than A. f allacis , and it
is very likely that they were interfering with its performance.

In the abandoned orchard, two-spotted mites were totally absent,
while red mites were always at low levels (Table 1). A. fallacis
was largely absent. However, other predacious mites increased to
1.70 mites per leaf, which is a rather high level, but still con-
siderably lower than predator levels in commercial orchard D. It
appears that the fewer numbers of mite predators in the abandoned
orchard were able to control red mites better than the larger num-
ber of predators in orchard D. This was probably because the dif-
ferent predator complex in the abandoned orchard was more efficient
in controlling red mites.

At the Belchertown Research Center, two-spotted mites were in
greatest abundance (causing severe leaf injury) and A_^ fallacis in
least abundance in the Zolone treated plot (Table 2). However , red
mites remained below damaging levels in all plots. In the Guthion
and Imidan plots, A_^ fallacis populations were high, keeping two-
spotted and red mites well below damaging levels. A. f allacis
levels were also high in the Benlate plot but failecPto keep two-
spotted mites from reaching damaging levels (Table 2) . This is
likely due to certain characteristics of Benlate (see below) which
adversely affect Aj_ fallacis populations. Yellow mites were absent
from all plots.

The combined results from the commercial orchards and the
Belchertown Research Center show that one or more of the materials
Zolone, Benlate, and Glyodin have a toxic and/or other effect on
populations of Aj_ fallacis . In addition, our recent laboratory
findings confirm results from Michigan (Dr. B.A. Croft's laboratory),
showing that Benlate, at orchard concentrations, severely reduces
the number of eggs laid by A_^ fallacis . Growers using these mate-
rials (Table 1) needed more miticide sprays, principally to control
two-spotted mites, than growers spraying only Guthion, Imidan,
Captan, and Cyprex. However, red mites can become a problem in some
orchards (i.e. in orchard D) using the latter pesticides because
the favorable environment may allow less efficient mite predators
to increase and interfere with A^ fallacis .

In the future, we plan further laboratory and field trials
aimed at determining which pesticides are safest for A_j_ fallacis
populations in our commercial orchards. This predator can be of
great assistance in suppressing harmful spider mites if its survival
can be guaranteed. In the next issue of Fruit Notes , we will
describe results of laboratory tests aimed at determining the
toxicity of a large variety of orchard pesticides to A. fallacis .

TABLE 2. Pesticides applied to apple trees at Belchertown
Research Center in 1977.

Number o£ mites/leaf at peak
abundance (July - August)

Pesticide

Rate/100 Gal

Red
Mites

Two-spotted

Mites

.70

,60

108

.80

.50

.74

A.
fallacis

Imidan 50wp
Guthion SOwp
Zolone 3EC
Benlate SOwp
Check

1.5 lb

10 oz .
1.5 pts
6 oz.

7.50
5.74
6.60
8.00

3 .70

1.48
2 .00
0.25
1.47
2.14

****************

APPLE TREE RESPONSE TO SUfD^^ER PRUNING

W. J.
Department

Lord and D. W. Greene

of Plant and Soil Sciences

Summer pruning has been practiced for centuries by European
gardeners in order to restrict vegetative growth and to induce the
formation of flowering spurs, but has not been widely applied in
commercial fruit growing. Considerable research on summer pruning
was conducted in the early 1900 's, and it produced widely differing
results depending on type of pruning, tree vigor, and cultivar. It
is very difficult to evaluate the results of these experiments
because these early reports generally described their experiments
too vaguely or the treatments were not replicated, but it should be
noted that in some of these trials summer pruning failed to suppress
vegetative growth, to increase flowering, to induce early bearing,
or to increase production. In some of these trials, the summer
pruning procedure was similar to that practiced during the dormant
season, whereas pruning as practiced by European gardeners to induce
fruitfulness involved removal of a portion of the current-season
shoot rather than removing whole branches or shoots. Despite all
the differences, however, it was generally agreed that summer prun-
ing restricted tree growth more than an equivalent amount of prun-
ing during dormancy.

This flurry of research on summer pruning in the early part of
the century led to the conclusion by some American pomologists that

the results were too unpredictable and the practice too laborious
to be of value in commercial orchards. But, now that we have greater
density o£ plantings (trees per acre) than in the past, interest in
vegetative growth control has been renewed. Furthermore, we have
substantial acreage o£ trees on size-controlling rootstocks that are
easier to prune because they are smaller, and we have mechanical
pruning devices that m.ake pruning quicker. Delicious, the major
cultivar in the U.S., tends to make excessive growth and to be
unfruitful, and therefore needs growth restriction. And still
further, as we look for ways to improve the calcium nutrition of
apples we see reports from Europe indicating that summer pruning
can increase fruit calcium levels. There is, therefore, ample reason
to re-examine the applicability of summer pruning to commercial fruit
production .

What is Summer Pruning?

The term summer pruning alone means little and only tells the
season of pruning. It may mean nothing more than the removal of
water sprouts or performing dormant -type pruning during the growing
season as a means of tree training. Summer pruning could mean making
detailed cuts on current season's shoots throughout the tree, using
hand-held pruning tools, to restrict vegetative growth and induce
the formation of flower buds on young trees. It also could mean
removal of current season's shoots and/or 1-year-old wood on the
periphery of the bearing tree with hand-operated pruning tools or
a mechanical pruning device to restrict tree growth or increase fruit
c a 1 c i um .

The object of our summer pruning investigations has been: (1)
to determine the vegetative and fruiting responses of young Delicious
and Cortland trees; and (2) to study its influence on quality of
fruit from Cortland and Mcintosh trees.

Definition of Terms

At this time a few terms used in this report should be defined
to avoid confusion that otherwise might arise in regard to their
meaning. Pinching will refer to the removal of only the tip of
current season's shoots. Heading will be the term used when cutting
current season' s shoots back to 4 to 6 mature leaves . Stubbing as
used here is to cut upright shoots on limbs about 1/4 to 1/2 inch
above their base, thus leaving a short stub.

Axillary buds are borne in the axils of the leaves on current
season's shoots. When a current season's shoot is pinched or headed,
the axillary bud or buds directly below the pruning cut may produce
growth; these are referred to as axillary spurs or shoots . We arbi-
trarily classified any growth less than 1 inch long but producing a
whorl of leaves as being an axillary spur . When shoots produced more
than an inch of extension grovv'th they were classified as axillary
shoots . The tip of an axillary spur will become either a leaf or
flower bud. The terminal bud on an axillary shoot also will become
either a leaf or flower bud.

-10-

Effect on Growth of Young Trees

Pruning while the shoots are still elongating tends to cause
new shoots to start growth from the axillary buds below the pruning
cuts. The amount of regrowth may show little correlation with
severity of pruning. We have foiond that Red Prince Delicious pro-
duces more of this regrowth than Cortland. Tree vigor at time of
pruning also is an important variable since the length of shoots
at time of pruning is highly correlated with amount of regrowth,
i.e., the longer the shoot, the greater the regrowth.

Pinching did not devitalize the trees in our studies, whereas
heading restricted the size of vigorous trees. Considerable regrowth
follows summer pruning of vigorous young trees in late-June through
mid- July. However, if substantial leaf surface is removed at this
time, regrowth does not compensate for the removed surface. July
and early-August appear feasible times for restricting tree size by
summer pruning, but regrowth may be less when pruning is done in
early-August .

Pinching and heading cuts on vigorous Red Prince Delicious
trees in early or mid-July frequently causes new shoots to start
growth from 2 or more of the axillary buds below the pruning cuts.
Thus, a proliferation of growing points occurs just as when trees
are sheared with mechanical pruning devices during dormant season.

Whether the proliferation of growing points can be considered
an unfavorable response in all cases remains to be proven. However,
clearly unfavorable responses to summer pruning have occurred. On
Cortland/7A trees, 181 of the shoots headed on July 18, 1976 were
dead in 1977; death of headed shoots occurred less frequently follow-
ing the July 1 and August 2 pruning dates. Many current season's
shoots on Cortland/7A and Red Prince Delicious/26 stubbed in 1977
failed to produce regrowth. In 1978, 71% and 50% of the stubs were
dead on the Cortland and Red Prince Delicious, respectively. Some
flowering from axillary flower buds and spurs has occurred in Sept-
ember of the year of pruning. Summer-pruned trees also have shown
a tendency to mature their wood later in the fall as evidenced by
delayed leaf abscission, and this may lead to winter injury. Fur-
thermore, Starkrimson trees that had been summer pruned by heading
cuts in 1976 made more growth than the control trees in 1977; thus,
the advantages of vegetative growth control in 1976 were lost in
1977 without follow-up summer pruning.

E ffect on Formation of Flowering Spurs

We wanted to determine if stubbing, heading, or pinching current
season's shoots in summer caused a flower bud to form immediately
below the cut. Stubbing is preferred in some fruit growing areas
because less regrowth is produced and thereby more chance for ini-
tiating flower buds than when a longer stub is left as with heading

11-

and pinching. Even though we stubbed shoots on Cortland/7A and Red
Prince Delicious/26 on June 21, July 5, or July 19 many were not
vigorous enough at time of pruning to produce an axillary flowering
spur or shoot. As previously mentioned, many of the stubs failing
to make regrowth in 1977 v\rere dead in 1978.

Heading and pinching on Cortland/7A in 1976 and 1977 caused
formation of some flowering axillary spurs or the development of
axillary shoots with a terminal flower bud. Since Cortland normally
produces some terminal flower buds, a terminal flower can form in
spite of considerable extension growth of axillary shoots from the
first leaf axil below the pruning cut. On Cortland we believe that
summer pruning merely eliminated some potential flower buds and
stimulated the formation of others since total bloom was not increased
in either year following pruning.

Heading and pinching procedures failed to induce the formation
of flowering spurs or shoots on Starkrimson Delicious/106 and Red
Prince Delicious/106 in 1976 but were somewhat successful on Red
Prince Delicious/106 and Red Prince Delicious/26 in 1977, probably
because conditions were very favorable for flower bud initiation as
evidenced by the snowball bloom in most orchards in 1978.

The Red Princ
the 1st leaf axil
were initiated on
initiated on axill
leaf axil below th
26, vvfhich had low
occurred on axilla
leaf axil . As wit
by the summer prun
pruned by heading
2nd and 3rd leaf h
trees .

e Delicious/10
following head
this axillary
ary spurs or £
e pruning. In
to moderate vi
ry spurs and s
h Cortland, to
ing . Furtherm
cuts both in 1
ad significant

6 made considerable
ing and pinching and
growth. However, fl
hort shoots developi
the case of the Red
gor in 1977, flower
hoots from both the
tal bloom was not in
ore. Red Prince Deli
976 and 1977 when th
ly less bloom in 197

regrowth from

no flower buds
ower buds were
ng from the 2nd

Prince Delicious/
bud initiation
1st, and 2nd
creased in 1978
ciousA06 summer
ey were in their
8 than the control

Heading and pinching in late-June and early-July were most
effective while pruning in mid-July or later had little effect on
flower initiation (Table 1).

TABLE 1. Time of summer pruning and percentage of tagged axillary spurs or
shoots that had terminal buds that bloomed the following year.

Time of pruning

Bloom, 1977
of Cortland buds
%

Time of
pruning

Bloon, :
Cortland
%

1978 of buds on:
Del/106 Del/26

21.9 a

3.3 b

1.4 b

6/21/77
7/19/77

47.6 a

42.7 a
15.7 b

25.1 a

14.2 a 13.4 b
2.1 b 4.1 b

7/1/76

7/1S/76

8/2/76

12-

Its Place in Massachusetts Apple Orchards

Performing dormant- type pruning during the summer has a place
in young apple orchards as a means of tree training. However,
summer pruning is laborious and certainly of doubtful value under
Massachusetts conditions as a direct stimulus for flower bud ini-
tiation on axillary spurs and shoots. To the contrary. Dr. G. E.
Stembridge at Clemson University, Clemson, South Carolina, obtained
substantial flower bud initiation following stubbing of 4-year-old
Delicious/106 in early summer, 1974. Furthermore, many of the
axillary spurs and shoots produced by late summer pruning initiated
flower buds in 1975. Stembridge stated in correspondence that he
thought the extra flowers produced by summer pruning were relatively
inconsequential to the productive capacity of the tree. A more
important consequence of the summer pruning was the removal of
unwanted vigor and better light penetration. In South Carolina,
growing conditions are probably more favorable for flower bud ini-
tiation following summer pruning than in Massachusetts. To the con-
trary, the problem of controlling vigor is probably less acute in
Massachusetts than in South Carolina.

Basically, Delicious is our only cultivar with which we have
problems of adequate fruitfulness on young trees whereas tree crowd-
ing and low fruit Ca is a problem with different cultivars in many
bearing orchards. Mid-July through early-August seems a suitable
timing for summer pruning to restrict vegetative growth; when prac-
ticed to increase fruit Ca, early August may be best.

Many answers are needed concerning the responses of our major
cultivars before we can suggest this procedure on other than a trial
basis only. Summer pruning is very laborious when done with hand
shears, thus one of the questions is, "Can it be performed with a
mechanical tree hedger?".

It certainly is possible that Rome and Cortland, which produce
part of their crop on 1-year-old wood, may not show favorable
responses to summer pruning if a high percentage of current season's
shoots are removed. Furthermore, we need to know the influence of
summer pruning on sun scald of fruit, and fruit maturity and keep-
ability in storage.

Research on summer pruning is being conducted in many fruit
growing areas and many questions concerning the practice will be
answered. Meanwhile, we urge caution to the growers currently
experimenting with summer pruning .

****************

-13-

THE EFFECT OF SUMMER PRUNING OF McINTOSH APPLE
TREES ON THE CALCIUM NUTRITION AND POSTHARVEST
QUALITY OF THE APPLES

William J. Bramlage and Mack Drake
Department of Plant and Soil Sciences

As we have searched for methods to increase the amounts of
calcium (Ca) in apples, we have become interested in the results
from Europe indicating that late summer pruning can improve Ca
nutrition of the fruit. It is logical to expect such a result
from late-summer pruning, since vegetation and fruit are competing
for what Ca is available within the tree, and vegetation is the
much stronger competitor. Therefore, removing vegetation late
enough so that regrowth does not occur should reduce much of the
competition and allow more of the available Ca to move into the
fruit .

But, will it work? To test the idea, we adopted the pruning
technique of A. P. Preston in England, which he found to work under
their conditions. This is a very severe pruning technique: all
current-year shoots are removed to their points of origin . We
applied this technique to 8 vigorous 12-year-old Mcintosh trees on
M.7 rootstock in 1975 and in 1976 within an experiment where we
were testing various methods of raising the Ca level in the fruit.
Pruning was done in early- August , 1 month before harvest, and
resulted in no regrowth in that season.

The effects of the pruning on the quality of the fruit were out-
standing. Ca content of the fruit at harvest in 1975 was 15% above
that of fruit from trees that had not been summer-pruned. Due to
reduced foliage, light penetration was much greater and the fruit
were much redder at harvest; however, there was no sun- scald on them
(although sun-scald did occur on Cortlands that were pruned in the
same way). After storage in either regular storage to January, or
in CA until mid-April, apples from the summer-pruned trees had much
less bitter pit, breakdown, and rot.

In 1976, the same trees were again pruned in the same way.
Again, the fruit were highly colored due to the excellent light pene-
tration, but were not sun-scalded. In this second year, summer
pruning increased fruit Ca by an amazing 60?;, and after storage the
quality of the fruit was outstanding: bitter pit and breakdown had
been virtually eliminated, and the fruit were substantially firmer
than ones from trees that were not summer pruned. Clearly, summer
pruning had effectively increased the amount of Ca in the apples and
had correspondingly improved their postharvest quality.

Should you consider using this pruning technique in your orchard?
We do not think so; we do not believe that the Preston technique can
be applied in New England without modification. We believe it is too
severe a method of summer pruning for Mcintosh in Massachusetts. Among
our concerns is the fact that in 1976 the trees produced many blossoms
at harvest time.

-14-

These results do, however, demonstrate that summer pruning may
be an important method of coping with Ca deficiency in apples. We
are now considering less severe pruning methods to see if we can
find a technique that is compatible with our growing conditions, and
yet will remove enough vegetation to significantly improve fruit Ca
levels. An important point in considering summer pruning is to recog-
nize that if pruning is done early and regrowth occurs, the new vege-
tation will increase the competition for available Ca ; if substantial
regrowth occurs, summer pruning may reduce the amount of Ca in the
fruit, and worsen their storage problems.

****************

All pesticides listed in this publication are registered and
cleared for suggested uses according to Federal registrations and
State Laws and regulations in effect on the date of this publica-
tion.

When trade names are used for identification, no product endorse-
ment is implied, nor is discrimination intended against similar
materials.

NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

15-

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William J. Lord
Extension Pomologist
University of Massachusetts
French Hall
Amherst, MA 01003

Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whaley
Director
Cooperative Agricultural Extension Work
Acts of May 8 and June 30, 1914

Official Business
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FRUITpr
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 43 (No. 5)

SEPTEMBER/OCTOBER 1978

TABLE OF CONTENTS

New England Fruit Meetings and Trade Show, 1979

Han/esting and Storing Apples:
A Time for Observing Details

Bruising of Apples After Packing

Controlled Atmosphere Storage Safety Precautions

Chokecherries: How to Recognize and Get Rid of Them

Miscellaneous Information on Orchard Mouse Control

Laboratory Toxicity of Pesticides and Growth Regulators
to Amblyseius fallacis, An Important Spider Mite
Predator in Massachusetts Apple Orchards

NEW ENGLAND FRUIT MEETINGS AND TRADE SHOW, 1979

The New England Fruit Meetings and Trade Show, as in the

past, will be held at the New Hampshire Highway Hotel, Goncord,

New Hampshire, The meetings are scheduled for January 10 and 11.

****************

HARVESTING AND STORING APPLES: A TIME FOR OBSERVING DETAILS

W. J. Bramlage
Department of Plant and Soil Sciences

The apple harvest season is a hectic time for a fruit grower.
His attention is often focused on his harvest labor, and perhaps
on his harvest sales operation. And, unfortunately, something
may have to "give". Don't let it be your storage operation! Short-
cuts or mistakes in September can mean disaster in April. If a
grower is to market quality fruit in the Spring, he must pay atten-
tion to details in the Fall. Some comments follow on things to
be watched .

VJeather . Hot
detrimental .
mature apples
coloring, esp
to harvesting
least 331 red
effective sea
period, the h
room. Unless
these hot app
into storage

weather shortly before and during harvest is generally
It ripens fruit rapidly, leading to harvest of over-
with shorter storage life. It results in poorer

ecially if night temperatures are high, and again leads
riper apples because it is necessary to wait for at
color. It increases susceptibility to scald, making

Id treatments crucial. If it's hot during the harvest

ot apples increase the heat load going into a storage
ample refrigeration is available, it is best to allow

les to cool overnight in the orchard, and bring them

early the next morning.

If the weather is cool during harvest, the prospects for high
quality fruit in the Spring are much better. Nevertheless, there
is need to get apples off the tree and into storage as quickly as
possible. The riper the fruit at harvest, the shorter is its
storage life.

With
about 28°
are fully
("bruises
to about
damage oc
thaw. If
the apple
softening
age. If
of time;

late varieties, freezing may occur. Apples freeze at
F. If they freeze, do not pick or handle them until they

thawed . Physical contact will produce visible damage
") when they thaw. Unless the fruit temperature falls
22°F, apples will survive freezing; at about 22°F,'' lethal
curs and they show browning and breakdown soon after they

browning and breakdown do not show up soon after thawing,
s have survived the freezing. However, any freezing causes

and probably leads to faster deterioriation during stor-
apples freeze, do not attempt to store them for long periods
dispose of them as quickly as possible.

Fruit maturity . Maturity is the stage of development at harvest.
If too immature at harvest, fruit will never develop top quality
flavor and may be more subject to shriveling, scald, bitterpit and
browncore after harvest. If overmature, fruit will deteriorate
quickly and be more subject to softening, breakdowns and rots.

How to identify maturity is a difficult question. Pressure
test, color (especially undercolor), abscission, and flavor are
helpful guides, but experience with your own fruit may be your
best measure. Use of growth regulators has made this an even more
difficult question. Alar* delays maturity, but not as much as
many people think. Its phenomenal drop control capability and its
delay of softening can be misleading. Do not delay harvest of
Alar*-treated fruit ; a significant amount of the firmness difference
between Alar*-treated and untreated fruits will disappear rapidly
during storage. Ethrel* hastens maturity, and despite our belief
that Ethrel*-treated fruits can be stored if^ harvested at the right
time, we think that it's hazardous to try to CA-store Ethrel*- treated
apples commercially. The hormone-type Stop-drop sprays also promote
maturation, and should be used with this understanding.

Further complicating the maturity problem is the use of red
strains and dwarfing rootstocks. Since for marketing reasons har-
vesting is usually gauged by red color, the red strains are prob-
ably an advantage to proper storage management since less mature
(and longer keeping) fruit may be harvested. However, among the
strains of 'Delicious' it is well known that some red strains mature
well ahead of others. Therefore, it cannot be assumed that red
strains are just like the standard strains except for color; other
criteria must also be watched. It is very likely that some root-
stocks influence maturity, although this must yet be defined. Again,
you cannot assume that fruits from dwarf ing-rootstock trees are
the same as those from seedling -rooted trees. You must watch these
fruits closely.

Just when to harvest apples for maximum storage life is perhaps
the most frustrating question to face. In Massachusetts, flesh
firmness of at least 15 to 17 lbs (if Alar*-treated, 16 to 17 lbs)
is considered essential for 'Mcintosh' if they are to be stored in
CA. If you are using a pressure- tester to gauge fruit maturity, be
sure you are using it properly . (See: "The Use of a Pressure Tester
to Measure Firmness of Apples''. Fruit Notes , March/April, 1977). In
Michigan, a simple test has been~devised to measure the amount of
ethylene gas being produced by apples as a means of determining
whether they are suitable for long-term or for short-term storage,
and it is being used commercially there, but we as yet have no per-
sonal experience with this test in Massachusetts.

Most of the problems due to harvesting slightly immature apples
can be dealt with, and these fruit will have the potential for long
storage. Most of the problems due to harvesting overmature apples

* Trade Name

cannot be dealt with except by rapid disposal o£ them. It is
better to pick a little too soon than a little too late . Over-
naturity is perhaps the greatest source of storage problems .

P re-storage operations . It is absolutely essential that apples
be cooled quickly and thoroughly after harvest. Ideally, they
should be cooled to 32°F within 24 to 36 hours, but in practice
it is sufficient to completely cool them in 7 days. However, few
growers have any idea what the temperature of their fruit actually
is in storage. (Air temperature is a poor gauge of fruit tempera-
ture.) Some growers who have measured fruit temperature during
storage with thermocouples have been shocked to learn how slowly
they are cooling. Many refrigeration systems are designed to
maintain temperatures after the apples are cool, and therefore do
not have the capacity to rapidly cool large volumes of fruit.
These rooms can only cool fruit adequately if they are loaded slowly
and carefully. Use of bulk bins increases the cooling problem,
since contact of moving cold air with the fruit is reduced. Fur-
thermore, bins are often arranged in the storage without regard
for air-flow patterns. Cold air must move over the surface of an
apple if it is to cool quickly. Inadequate cooling is undoubtedly
a major source of storage problems .

Varieties susceptible to scald should be treated with an
inhibitor before storage if they are to be stored beyond early
January. Postharvest dips are very effective if used properly.
Diphenylamine, at 1000 ppm for Mcintosh, 1000-1500 ppm for Delicious,
and 2000 ppm for Cortland, is generally the preferred inhibitor
except for Golden Delicious, but Ethoxyquin at 2700 ppm may also be
used. Tests in New York indicate that liquid-concentrate DPA is
more effective than wettable powder DPA, since it is more stable in
suspension and less toxic to the fruit, although it requires addi-
tion of a defoaming agent. Surveys in New York revealed that many
dip tanks contained considerably less inhibitor than recommended,
due to dilution of solution by wet apples, removal of inhibitor on
the surface of treated fruit, and breakdown of inhibitor in the dip
tank. New York recommendations now suggest that when DPA dips are
being replenished (brought back to volume), double- strength solution
should be added to the tank, to compensate for this diminished con-
centration of the inhibitor.

If a postharvest dip is being used, it is wise to add a fungi-
cide. A circular on "New England Suggestions for Postharvest Fruit
Rot and Storage Scald Control" is available from your Regional Fruit
Specialist. Benlate* has given excellent decay control on apples,
but it should be noted that Benlate* seems to be unusually conducive
to development of resistant strains of fungi. If Benlate* has been
used during the growing season, there is a possibility that a resis-
tant strain is present on the fruit. Furthermore, it is suggested
that treated fruit be removed from the dipping area as quickly as
feasible to avoid buildup of resistant spores. Much can be done to
reduce storage decay problems by preharvest sanitation treatments;
this was carefully described in Fruit Notes by Dr. C. J. Gilgut in
1972 (Fruit Notes, Sept .-Oct. :pp 2-7) .

-4

If a postharvest dip is used, calcium chloride (CaCl^) may also
he added to the solution. Adequate calcium levels in the fruit are
essential for long storage life. If calcium treatments have not been
applied during the season, or if significant amounts of cork or
bitterpit are present in the fruit, 24 to 32 lbs of CaCl^/100 gallons
may be added to the dip solution. The calcium residue oft the surface
of the fruit will continue to enter the apples during storage, and
can substantially reduce the development of fruit disorders.

Storage operations . CA rooms should be filled and sealed as quickly
as the apples can be thoro ughly cooled . The longer the fruit remain
in air after harvest, the less benefit CA will have on them. It
should be no more than 2 weeks between the time you start loading
a room and when that room is sealed. However, to accomplish this
you must have sufficient refrigeration capacity in that room to '
remove the field heat, or else have a special room with extra cooling
capacity m which you do the initial cooling of the fruit. If you
must choose between thorough cooling and early sealing, choose
thorough cooling . Don't overload your cooling capacity to get an
early seal.

The exact temperature at which you store your fruit is a criti-
cal factor in determining how well they will keep. You must have a
highly reliable, calibrated thermometer in the storage room, and
you must store the fruit a_t the recommended temperature, not near
It. A storage temperature that is only 1° or 2°F above the recom-
mended temperature will significantly reduce the storage life of
your fruit.

Traditionally, a relative humidity of 90 to 95% has been recom-
mended for apple storages. It has been clearly shown in recent years
that if the R.H. is very near 1001, apples are more subject to break-
down disorders; on the other hand, if R.H. is below 90% the apples
will shrivel. However, we know of no storage that is equipped to
monitor R.H., and doubt if very many storage operators ever measure
R.H. (a slmg psychrometer is a good tool for measuring humidity).
In this situation, we feel that storages are more likely to have too
low humidity than too high a humidity, since it is not easy to
maintain an atmosphere close to 100% R.H. Therefore, we recommend
that storage operators do everything possible to maintain as moist
an atmosphere as possible in the storage.

For CA storage, our recommended conditions are the same as in
recent years. Mcintosh and Macoun should be stored at 1% 0. , 5% CO?, and
38°F. Baldwin, Delicious, Empire, Golden Delicious, Idared, Northern
Spy, Rome Beauty, and Spartan should be stored at 3% 0^, 1% COo, and
32°F. Cortland may be stored under either regime, but store best as
part of the latter group of varieties.

Careful observations and record keeping do not end with attain-
ment of the CA condition. Atmosphere and temperature should be
monitored and recorded daily. If the 0, falls below 3%, it should

be brought back up immediately . Storage conditions should be
watched closely and recorded. (The gas analyzer, the aspirator bulb,
and all sample lines should have been carefully checked before seal-
ing, and any indication of malfunction during storage should be
checked-out immediately. Porous aspirator bulbs, which result in
higher O2 readings than actually exist in the room, have been respon-
sible for severe low O2 injury to fruit.) It is well to sample fruit
periodically during the storage season. (See: "The Soft Mcintosh
Problem", Fruit Notes, Sept. -Oct. 1974: pp. 1-4)

Successful storage operation requires attention to details,
from the beginning of harvest to the sale of the last apples. Any
mistake or oversight can be disastrous, especially with the trend
to longer storage periods: the longer apples are kept, the more
important are the details. The successful operator should recog-
nize a problem as it develops, and adjust his marketing practices
accordingly. For example, if cooling in some fruits has been inade-
quate, these fruits should be disposed of as quickly as is feasible.
Long-term storage should be attempted only with apples that have
"everything going for them". Long-term CA does not correct mistakes;
it only underlines them.

****************

BRUISING OF APPLES AFTER PACKING

W. J. Bramlage
Department of Plant and Soil Sciences

Dr. George Mattus has been conducting extensive studies in recent
years on the condition of apples in the distribution centers and
retail stores of Virginia. He has often observed a great deal of
impact bruising on apples, indicating damage that is occurring during
handling of the packed fruit. To determine some of the factors
associated with this bruising and to try to find ways of reducing
it. Dr. Mattus conducted a series of tests this Spring that pro-
duced some impressive results. Some of his findings are reported
here.

In one series of tests, carefully harvested apples of 5 dif-
ferent cultivars were packed in fiber or foam trays, which were
packed in cartons. Both 88- and 100-size packs were tested. In
addition, 6 different cultivars were packed in 3- lb poly bags,
which were placed in 12-bag cartons. Two different cartons for
the bags were tested: 1 carton had 12 single cells, 1 for each
bag, whereas the other carton had only 4 cells, so that 3 bags
were packed in each cell -- 2 vertically and 1 horizontally.

Each carton was dropped once , from either a 6- inch or a 12-
inch height. Injury to the fruit was tabulated and is shown in
Table 1.

TABLE 1. BRUISING OF APPLES, PACKED IN TRAYS OR POLY BAGS,
FOLLOWING A SINGLE DROP OF A CARTON.

DAMAGE TO FRUIT

Sq . cm .

Packing Height „ -.^ !J°-.°^ of bruised %with

variable o£ d?op t ^^^^ bruises area per cuts or

^ bruises per apple apple punctures

CARTONS CONTAINING TRAYS

Type of Tray

Fiber 6" 64 0.9 62

Foam 6" 52 0.7 42

Fiber 12" 70 1.0 116

Foam 12" 54 0.7 54

BAG-MASTER CARTONS

No. of Cells

12 6" 68 1.1 109 2.9

4 6" 69 1.2 127 2.2

12 12" 77 1.4 223 3.5

4 12" 80 1.5 240 4.0

The results dramatically demonstrate the potential for damage to
fruit after packing. A single 6 -inch drop of a carton (measure it!)
bruised over 50^ of the fruit . Apples packed in foam trays bruised
less than those packed in either fiber trays or poly bags. Apples
packed in poly bags, rather than in trays, received more bruises
from the drop, and these bruises were much larger than those on
tray-packed fruit. In addition, the apples in poly bags received
cuts and punctures from the drop, even the one from only a 6- inch
height.

Interestingly, the 12-inch drop was not much worse on the
fruit than the 6-inch drop. Also, it made little difference
whether the poly bags were packed in 4-cell or 12-cell cartons.

In another series of tests. Golden Delicious apples in either
fiber or foam trays were packed in a number of different ways to
find out more about what influences bruising. In these tests, the
cartons of apples taken directly out of cold storage were all
dropped once from a 12-inch height.

Results are shown in Table 2. These tests shcv/ed that (1)
more injury occurred in dry fiber trays than in moist fiber trays;
(2) more injury occurred in shallow fiber trays than in deep-cell
fiber trays; (3) damage to fruit packed in fiber trays can be
reduced by individually wrapping apples in paper, padding the
bottom of the carton, and especially by putting pads between layers;
and (4) cold apples are more subject to bruising than are warm
apples .

Clearly, the way apples are packed influences the amount of
damage inflicted by impact upon the carton. However, the clearest
m.essage from these studies is: Don't drop cartons of apples!

TABLE 2. EFFECTS OF MODIFICATIONS OF TRAY PACKING ON BRUISING
OF GOLDEN DELICIOUS APPLES AFTER DROPPING A CARTON
OF 100-SIZE TRAYS 12 INCHES.

DAIvIAGE TO FRUIT

Packing
variable

% with
bruises

Dry fiber trays
Moist fiber trays
Foam trays

72
70

No, of bruises
per apple

Sq . cm . of
bruised area
per apple

Deep-cell fiber
trays

1.7
1.6
1.4

1.1

210
169
102

Dry fiber trays-- +
paper wraps on all

apples, OR

2 pads in bottom
of carton, OR

filled paper pad
on each layer, OR

Urethane sheet on
each layer

ing 20"C apples

1.2

0.8

0.9
1.3

100
98
41
93

A************ ft**

CONTROLLED ATMOSPHERE STORAGE SAFETY PRECAUTIONS

G. D, Blanpied, Pomology Department

and
L. D. Baker, Agricultural Engineering Department

Cornell University

[Editors' Note: Earlier this year, a life was lost in the Hudson
Valley Region of New York due to lack of precautions when enter-
ing a CA room. We urge that this article be prominently displayed
so that a repeat of this tragedy may be avoided.]

Occasionally, someone must enter a CA storage to obtain fruit
samples, to replace a broken fan belt, burned out motor, to check
for plugged nozzles, or to make other equipment repairs. The
atmosphere in the CA room probably contains less than 5% oxygen.
Outside air is about 21% oxygen. Do you know what happens to you
in a CA storage?

Symptoms of Asphyxia '^

17% oxygen
12-16% oxygen -

10-14% oxygen

candle is extinguished.

breathing increased and pulse rate accelerated.

ability to maintain attention and to think
clearly is diminished, but can be restored
with effort.

muscular coordination for finer skilled
movements is somewhat disturbed.

consciousness continues, but judgement becomes
faulty.

severe injuries (burns, bruises, broken bones)
may cause no pain.

muscular efforts lead to rapid fatigue, may
permanently injure the heart, and may induce
fainting .

6-10% oxygen - nausea and vomiting may appear.

legs give way, person cannot walk, stand, or
even crawl. This is often the first and only
warning, and it comes too late. The person
may realize he is dying, but he does not
greatly care. It is all quite painless.

less than

6-6 oxygen - loss of consciousness in 30-45 seconds if

resting, sooner if active.

breathing in gasps, followed by convulsive
movements, then breathing stops.

heart may continue beating a few minutes,
then it stops.

REMEMBER: THE CA STORAGE CONTAINS LESS THAN 5% OXYGEN

To avoid problems, plan ahead.
Before Sealing the Room

(1) The manhole in the gastight door should be at least
24 X 30 inches high to accommodate a large person with breath-
ing equipment strapped to his/her back.

(2) There should be a ladder inside the room, near the
refrigeration unit. When loading the room, leave sufficient
space to move and use the ladder around the equipment.

(3) Place a danger sign on each gastight door. "DANGER -
OXYGEN TOO LOW FOR PEOPLE TO BREATHE" or other suitable warn-
ing should be printed on the sign using letters at least 1-1/2
inches high.

Entering a Sealed CA Room

If you have a New York State CA registration and need to
break the seal before the end of the initial 90 day period,
notify the New York Department of Agriculture and Markets in
advance.

If you must go to a place in the CA room where you cannot
be EASILY DRAGGED TO THE DOOR, open the room and vent with air
until the oxygen is 21% before entering (see item 6 on next
page) .

If you need to enter a sealed CA room (one from which
you can be easily drag-rescued) proceed as follows:

(1) Have at least 2 sets of tested breathing apparatus
ready. If you don't own your own equipment, know where
functional breathing equipment can be borrowed or rented.
The breathing equipment should be fed with air (compressed
or fan blown) not pure oxygen. The mask should be held in
place with straps. Scuba diving equipment is dangerous to
use because the mouthpiece may fall from your mouth if you
fall.

-10-

(2) Check the breathing apparatus. Does it deliver air
to the mask? Is the tank full of air? The two individuals
using the equipment should put on the breathing equipment in
normal air and use up a tank of air while doing routine tasks,
They can then become accustomed to the apparatus, learn some-
thing about its limitations and hear the alarm when the air
level in the tank is nearly exhausted. The tanks should then
be refilled prior to use in the CA storage.

(3) Review the symptoms of asphyxia so you won't take
any chances .

(4) Remove the window in the gastight door of the CA
storage room.

(5) The repair person enters the CA room with breathing
apparatus. The back-up person must keep the repair person in
sight. If this can be achieved from outside the CA room, the
back-up person should be ready to enter the CA room, but not
use the air until necessary. The back-up person may need to
enter the CA room to keep the repair person in sight. If
both people are in the CA room and one person's warning bell
rings to signal the tank is almost empty, then both people
should exit the CA room. If one must climb the ladder, the
second should stay on the floor. If both need to climb the
ladder to maintain visual communication, drag-rescue cannot
be accomplished. Open the room and vent with air.

(6) If you vent the CA room with air and then need to
restore the CA atmosphere, but do not have access to an
oxygen burner, you can flush out the oxygen with nitrogen
gas. Order the nitrogen gas in the liquid form (large thermos
bottles), in trailer truck cylinders, or in regular cylinders
with a manifold. A tightly packed room will require about 2
cubic feet and a room with plenty of free air space will
require about 3 cubic feet of nitrogen gas per bushel to
lower the oxygen concentration from 21% to 5%. Use a garden
hose to deliver the nitrogen gas to the intake of the blower
in the CA room. Leave the porthole open to relieve pressure
in the room.

The description of asphyxia was taken from Noxious Gases and
the Principles of Respiration Influencing Their Action by Yandell
Henterson § Howard W. Haggard. Reinhold Publishing Corp . , 330
West 42nd Street, New York, N.Y.

****************

CHOKECHERRIES: HOW TO RECOGNIZE AND GET RID OF THEM

Georgene Moizuk Bramlage
Leverett, MA

The importance of being able to identify chokecherry trees is
that they serve as alternate hosts for X-disease, a very destructive
disease of peach, nectarine, sweet cherry, and tart cherry trees.
If the leaves of a wild cherry tree turn red or yellow in July or
August when the leaves of other trees are still green, this is
evidence that the tree is an X-disease -infected chokecherry.

Control of X-disease of stone fruits demands control of choke-
cherries. All chokecherry trees within at least 500 feet of any
stone fruit trees or future stone fruit site should be completely
eradicated. However, since neither the rum cherry nor the pin
cherry harbors X-disease, these trees are perfectly harmless to
stone fruit orchards . Illustrations and descriptions of these
three kinds of cherry trees can be found below^

The easiest way for the "novice'
is by their fruit and fruiting habit
is borne in an umbel

to identify the cherry trees
The fruit of the pin cherry

The fruit

raceme

the

both the

rum cherry and
but the calyx

rum cherry.

choke cherry is
cup persists on

borne in a
the fruit of

Prunus serotino
block/ rum cherry

Fig. 1 . The leaf shape of
cherry is long and narrow,

the rum
and the
turn inward,
with

shiny

serrations are dull and

The leaves are thick and

dense, reddish brown pubescence (fuzz)
along the back of the midrib. The
glands on the leaf stem are either
small and inconspicuous, or absent .
The fruit is borne in a raceme and
ripens in late summer . The calyx
cu p persists on the Truit . Rum cherry
may grow into a tree up to 50 feet or
more , and the bark on a two year old
or older tree is dark brown to black ,
and the lenticels on the bark are
small and numerous.

Fig. 1

-12

Fig

Fig. 2

_. The

cherry is bro

leaf shape of the rhoke-
ad with the sharp saw-
like teeth pointing outward. The

leaves are fa
compared wiTE
there is litt

The glands on
and prominent
young leaves ,
a raceme and
before that o

irly dull and thin when
the rum cherry , and

le or no pubescence .
the leaf stem, are large

, especially on large
The fruit is borne in

ripens in mid-sum m e r

f the rum cherry

The

calv x cup does not per sis on the frui-
Chokecherries

shrubs up to

are usually found as

15 feet tall with red -

brown to dark bro\\Ti bark , and only a
few large lenticels on the shiny bark,

Fig. 5 . The leaf shape of the pin
cherry is long, pointed, and narrow
with the serrations small and fine ,
and sharply hooked . There is little
or no pubescence (fuzz) on the
backs of the leaves. The glands on
the leaf stem are either small and
inconspicuous, or absent . The fruit
is borne in an umbel anxT ripens in
mid- summer . Pin cherry may also grow
into a tree up to 50 feet or more ,
and the bark on the older trees is
distinctly reddish brown , and the
lenticels on the bark are fe w and
large .

Fig

Eradication

If you find that chokecherries are in the vicinity of your
stone fruit trees, what is the best way to eradicate them? The
chokecherry is difficult to kill due to its habit of sprouting
freely from the roots. Cutting or mowing is not effective; it
merely results in a thicket of sprouts which require further cut-
ting. Satisfactory treatment requires use of a chemical agent
that will be carried down to the roots and kill them, thus pre-
venting further sprouting.

The suggested material for this is Ammate-X* (AMS) , at the
rate of 4 lbs per gallon of water. It may be applied as either

Trade Name

■13-

a stump treatment or as a "frill" treatment. Stump treatment is
the application of the chemical to freshly cut stumps, thoroughly
drenching the entire stump surface. "Frill" treatment is done by
making cuts above the ground around the tree, using an axe or
hatchet in a downward motion to expose the "growing region" of
the trunk, and to leave openings to hold the material. These
cuts are then filled with the chemical. Frill treatment is a con-
venient and effective way to kill trees of larger diameter.

Eradication of chokecherry with Ammate-X* is effective any
time of the year except when the ground is frozen, or when there
is snow or water on the ground around the trees. However, when
using this chemical, follow the instructions on the label care-
fu lly . For further information on brush control, you may obtain
tHe "1978 New England Chemical Brush Control in Non-Food Crop
Areas and in Christmas Tree Stands" circular from your Regional
Specialist .

****************

MISCELLANEOUS INFORMATION ON ORCHARD MOUSE CONTROL

Edward R. Ladd
U. S. Department of the Interior
Fish and Wildlife Service

We have checked a few orchards for meadow mice and find the
population is about the same as 1977. If it continues at this
level, orchardists can expect a high level of tree damage this
winter unless an adequate baiting program is performed.

The bait application should be made in October after harvest
of the apple crop. Early application is usually not advisable
since meadow mice continue to reproduce until Fall. Consequently,
the mice that remain after an early bait application can easily
regain their reduced numbers by Fall.

Meadow mice must have a dense cover of grass or other plants
for their survival. Thus, close and complete mowing of the entire
orchard will remove much of this needed cover and make the area
less attractive to mice. Time the mowing so that it will make
distribution of baits easier.

In addition to mowing and baiting it is advisable to perform
these practices in buffer strips around as many tree blocks as
possible. In the past few years there have been several instances
where the outer rows of trees have received damage by mice in spite of
a good baiting program within the orchard. In these cases, the
mice may have moved in under snow cover from surrounding areas.
Although a buffer strip is not totally effective, it does increase
the travel distance for the mice and frequently will reduce damage
from mice migrating into the orchard.

-14

Assuming that a mid-winter thaw will occur, make plans to
check those orchard areas known to have high mouse populations.
Have sufficient bait available to hand treat those blocks that*
have mouse holes and runways in the snow. This spot treatment
should reduce possible mid-winter tree damage.

Do not exceed label restrictions when baiting and distribute
them carefully. Baits, when properly placed, should be in vege-
tation at soil level; this is where the mice are. Baits on bare
ground or suspended in the vegetation are wasted and may be easily
found by animals other than orchard mice.

****************

LABORATORY TOXICITY OF PESTICIDES AND GROWTH REGULATORS
TO AMBLYSEIUS FALLACIS , AN IMPORTANT SPIDER MITE
PREDATOR IN MASSACHUSETTS APPLE ORCHARDS

Robert G. Hislop, Charles Acker, Nancy Alves, and Ronald J. Prokopy
Department of Entomology, Fernald Hall
University of Massachusetts

In the last issue of Fruit Notes (July/August, 1978), we
described results of 1977 studies aimed at determining the toxicity
of orchard pesticides to field populations of Amblyseius fallacis,
a key predator of red and two-spotted spider mites in Massachusetts
apple orchards. Combined results from several commercial orchards
and our Belchertown research plots demonstrated that application
of orchard concentrations of Zolone, Benlate, and perhaps also
Glyodin reduced populations of A. fallacis in the trees, resulting
in spider mite outbreaks. On tEe" other hand, use of Imidan, Guthion
Captan, and Cyprex permitted buildup of A. fallacis , usually result-
ing in effective suppression of spider mTtes, especially two-
spotted mites.

Here, we discuss results of laboratory tests, carried out in
conjunction with our 1977 and current field trials, aimed at deter-
mining the direct and residual toxicities of pesticides to a
strain of A^ fallacis from the Bishop orchard in Shelburne.

Three principal experiments were performed: (A) toxicity
tests of orchard materials at recommended field rates; (B) toxicity
tests of principal pesticides (i.e. those in greatest use) at three
different rates; and (C) tests of the influence of pesticide resi-
dues on the reproductive capability of A^ fallacis .

Direct Toxicity of Spray Materials to A, fallaois

To determine the direct toxicity of orchard spray materials to
A- fallacis , we used double-stick tape to affix adult females to
microscope slides. The slides were then dipped into solutions of

15-

the spray materials, which included a variety of insecticides,
miticides, fungicides, herbicides, and growth regulators. There
were five replicates (18 mites per replicate) for each rate of each
material. Control slides were dipped into water. Mortality of A.
fallacis was determined at 48 hours after treatment.

Results with materials tested at recommended field rates are
presented in Table 1. Materials with a toxicity of 70-100% are
considered highly toxic, 30-70% moderately toxic, and O-SOI of low
toxicity. Materials of high toxicity were: Zolone (both EC and
KP), Systox, Sevin, Diazinon, Carzol, Paraquat, and Roundup.
Materials of moderate toxicity were: Phosphamidon (4 oz. rate,
and 1 oz. rate), Kelthane, Plictran, and Alar.

TABLE 1. TOXICITY OF ORCHARD SPRAY MATERIALS AT RECOMMENDED
FIELD RATES TO Amblyseius fallacis (BISHOP STRAIN).

MATERIAL

RATE/
100 GALS

MORTALITY
("O

TOXICITY
RATING

INSECTICIDES

Zolone (phosalone) 3EC
Zolone (phosalone) 25WP
Systox (demeton) 6EC
Sevin (carbaryl) 5 0WP
Diazinon 50WP

Phosphamidon (dimecron) 8EC
Phosphamidon (dimecron) SEC
Thiodan (endosulfan) 50WP
Malathion 2 5WP
Imidan (Phosmet) 50 WP
Guthion (azinphosmethy 1)

50WP
Methoxychlor 50WP

MITICIDES

Carzol (formetenate

1.5

pts

100

High

4.0

lbs

High

3.0

100

High

1.0

100

High

1.0

High

4.0

Moderate

1.0

Moderate

1.0

Low

2.0

lbs

Low

1.5

lbs

Low

10.0

Low

3.0

lbs

Low

hydrochloride) 92SP

8.0

High

Kelthane (dicofol)

35WP

1.3

lbs

Moderate

*Plictran (cyhexatin) 50 WP

6 .0

Moderate

Omite (propargite)

30WP

1.5

lbs

Low

Vendex 50WP

0.5

Low

FUNGICIDES

Glyodex WP

0,5

Low

**Glyodin 30%EC

1.5

pts

Low

Dikar WP

1.5

lbs

Low

Benlate (benomyl) :

5 WP

6 .0

Low

Thiram (thylate) 65WP

1.0

Low

TABLE 1. (Continued)

MATERIAL

RATE/
100 GALS

MORTALITY

TOXICITY
RATING

FUNGICIDES (cont'd)

Phygon WP

Captan 50WP

Ferbam 76WP

Cyprex (dodine) 65WP

0.5 lb
2.0 lbs
1.5 lbs
6 .0 oz

5
9

1
12

HERBICIDES

Paraquat CL (paraquat)

2 lbs/gal 2 .0 qts

Roundup (glyphosate)

2 lbs/gal 1,

Princep (simazine) 80WP 3,

GROWTH REGULATORS

Alar-85 (deminozide) 85WP 1.0
Ethrel (ethephon) 21.61 liq 0.5
Fruitone-N

(naphthaleneacetic acid)

1/4 lb = 10 ppm
Amid-Thin W

(naphthaleneacetamide)
1/4 lb = 25 ppm

FO LIAR NUTRIENT SPRAY
CaClo

gal
lbs

lb
pt

10.0 ppm

2 5.0 ppm

3.0 lbs

100

100
5

33
6

Low
Low
Low
Low

High

High
Low

Moderate
Low

Low

* Proved to be of low toxicity to Carlson orchard strain of
A. fallacis .

** Proved to be of moderate toxicity to Carlson orchard strain
of A. fallacis .

All of the

other materials tested, inc

calcium chl

oride foliar

nutrient spray

high toxici

ty of Zolone

3EC contrasted

Imidan and

Guthion, thu

s supporting ou

din was of

low toxicity

to this strain

additional

results indi

cated that it w

the strain

of A. fallacis from the Car

Further fie

:ld trials wi

th Glyodin are

late was of

low direct

toxicity to thi

severe anti reproductive

effects (see b

luding all fungicides and
, were of low toxicity. The

with the low toxicity of
r 1977 field results. Glyo-

of A. fallacis , although
as oT~"moderate toxicity to
Ison orchard in Harvard,
currently in progress . Ben-
s predator, although it had
elow) . Sprays highly toxic

-17-

to A. fallacis are not recommended for use after bloom, and those
witH~"moderate toxicities of 401 or greater are not recommended
for use after the first cover spray. Although most Aj_ fallacis
are still in the ground cover at the time of the first cover spray,
even small amounts of highly toxic materials falling on the ground
cover can severely injure them.

Results with principal orchard pesticides tested at three
different concentrations are given in Table 2. Five of the
m.aterials (Imidan, Guthion, Cyprex, Captan, and Benlate) were of
low toxicity to A^ fallacis even at double the recommended field
concentration. Zolone 3EC was highly toxic even at half the recom-
mended field rate, while Glyodin 30% was moderately toxic at double
the recommended field rate.

TABLE 2. TOXICITY OF PRINCIPAL ORCHARD PESTICIDES AT THREE
DIFFERENT RATES (ONE-HALF, ONE, AND TWO TIMES THE
RECOMMENDED RATE) TO Ambly s eius fallacis (BISHOP
STRAIN) .

MORTALITY (?6)

1/2 TWICE

RECOMMENDED RECOMMENDED RECOMMENDED
PESTICIDE RATE RATE* RATE

Imidan (phosmet) 50WP 2 10 15

Guthion (azinphosmethyl) 5 0WP 4 10 12

Zolone (phosalone) 3EC 94 100 100

Benlate (benomyl) 50WP 7 15 14

Cyprex (dodine) 65WP 5 12 15

Captan 50WP 4 9 18

Glyodin 30IEC 5 21 48

* See Table 1.

Influence of Pesticides on Reproductive Capability of A. fallacis

To test the influence of pesticide residues on the reproduc-
tive capability of A_^ fallacis , adult females were placed on
detached living bean leaves which had been previously dipped into
a solution of pesticide at the recommended orchard rate and allowed
to dry for 3 hours. We daily offered the predators two- spotted
mites as food and counted their eggs over the succeeding 2-week
period. (The two-spotted mites caused only slight damage to the
leaves.) Each treatment, (including water-dipped check leaves)
was replicated 14 times.

The results are given in Table 3. Five of the pesticides
tested (Imidan, Guthion, Cyprex, Captan, and Glyodin) had little
or no apparent effect on A^ fallacis reproductive ability. However,
the presence of Benlate residues totally destroyed the ability of

18-

of this predator to develop and/or deposit eggs. At the end of
the two-week test period, not even a single predator mite regained
reproductive capability. Therefore, we do not recommend use of
Benlate after the first cover spray, when A^ fallacis are entering
the trees. Leaf residues of Zolone 3EC killed all A. fallacis ,
thus preventing successful completion of this test.

TABLE 3. INFLUENCE OF PESTICIDE RESIDUES
REPRODUCTIVE CAPABILITY.

ON Mblyseius fallacis

PESTICIDE*

AVERAGE NO. EGGS/A. fallacis FEMALE**

TREATED LEAVES

CHECK LEAVES

Imidan (phosmet) 50WP 17.5

Guthion (azinphosmethyl) 50WP 21.6

Zolone (phosalone) 3EC dead

Benlate (benomyl) 50WP

Cyprex (dodine) 65WP 21.0

Captan 50WP 21.0

Glyodin 30%EC 19.8

20.7
19.1
23.4
22.6
22.2
20,4
21.5

* Applied at recommended orchard rate (see Table 1).
** 14-day egg totals.

Conclusions

The laboratory data presented here thus support our sugges-
tions based on earlier field studies that certain orchard spray
materials are harmful in different ways to populations of A.
fallacis . For example, combined field and laboratory resuITs
clearly demonstrate that the directly toxic effects of Zolone
(both EC and WP) and Sevin, and the indirectly toxic (antirepro-
ductive) effects of Benlate can have serious consequences to
to populations of A_^ fallacis , thus creating spider mite outbreaks
Care should therefore be taken when deciding which orchard spray
materials to use for sound pest management. In the future, we
will continue our field and laboratory testing of the influence
of orchard spray materials on population buildup of our principal
mite predator, Amblyseius fallacis , in our apple orchards.

****************

NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

Cooperative Extension Service
University of Massachusetts
Amherst. Massachusetts
R. S. Whaley
Director
Cooperative Agricultural Extension Work
Acts of May 8 and June 30, 1914

Official Business
Penalty for Private Use, $300.

POSTAGE AND FEES PAID

U.S. DEPARTMENT OF

AGRICULTURE

AGR 101

BULK THIRD CLASS MAIL PERMIT

FRUITpf
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

W. J.

EDITORS
LORD AND W. J. BRAMLAGE

Vol. 43 (No. 6)
NOVEMBER/ DECEMBER 1978

TABLE OF CONTENTS

Winter Trunk Injury to Apples

Evaluation of Alar and Ethrel on the Cold
Hardiness of 'Mcintosh' and 'Delicious
Apple Trees

Quince Rust on Apple

Spider Mite Substances Influencing Searching

Behavior of the Mite Predator, Amblyseius

fallacis, on Apples
Fruit Notes Index for 1978

WINTER TRUNK INJURY TO APPLES

D. A, Kollas, Extension Pomologist
University of Connecticut
Storrs, Connecticut

In the spring and summer of 1976, many orchardists became aware
of extensive winter injury to the trunks of apple trees. Winter cold
injury has not appeared on such a large scale in Southern New England
for many years. This article is written to review some of the cur-
rent knowledge about cold injury and to relate it to the winter
injury of 1975-76. In reviewing the literature it is apparent that
we still lack a good understanding of cold injury and cold hardiness.

For many years, the standard way to study cold hardiness has
been to collect samples of shoot, bark, or bud tissue at various
times during the year, and expose it under controlled laboratory
conditions to freezing temperatures. The resulting damage is then
related to conditions that might influence cold hardiness. The
researcher has only limited control over conditions under which the
tree stood in the orchard. Every season is unique in its sunlight,
temperature, rainfall, wind and snow conditions. Consequently, pro-
gress in relating cold hardiness to any single one of these, and
other factors, is very slow.

Many studies of cold injury have led researchers to conclude
that when low temperature causes direct injury to woody plant tissues
it is either because ice has formed within the tissue cells, or
because the tissue has dehydrated due to ice formation. Cells of
living tissues contain protoplasm, the stuff that carries on basic
life processes. A major constituent of protoplasm is water. If
this water freezes to ice in the protoplasm, the protoplasm is
destroyed and death is assured.

Woody plants that survive New England winters are able to avoid
ice formation within the protoplasm as a result of a process known
as acclimation. The acclimation process can be initiated by the
shortening day length of August or September, and by temperatures
below about 28°F. Only nongrowing (dormant) plants can acclimate,
and become hardy to sub-freezing temperatures.

Just what changes occur during acclimation that make survival
to freezing temperatures possible are still not known. It is known
that the acclimation process takes time. Exposure of the plant to
temperatures below about 28°F can, over a period of several days,
result in hardiness to temperatures of near zero °F if other factors
are favorable. Exposure, for a couple of weeks can result in maximum
cold hardiness. But all tissues in a plant do not develop hardiness
in the same way, or to the same degree. Dormant apple flower buds,
for example, are hardy to 0°F long before trunk bark develops much
cold resistance .

Other factors affect the acclimation process, so that resis-
tance to very low temperatures does not always result from exposure
to below freezing temperature. It is pretty well established that
conditions which favor accumulation of carbohydrates in the bark
and woody tissue also favor acclimation to low temperature. Maxi-
mum accumulation of carbohydrates depends on active photosynthetic
activity in the whole tree for the whole growing season. Foliage
diaease or injury, inadequate water or nutrition, shading, severe
hail damage, or a growing season shortened by early frost will
obviously limit photosynthetic production of carbohydrates. It is
also recognized that a heavy fruit crop will draw off carbohydrates
that would otherwise be available for storage in the tree tissues.
There is some evidence also that chemicals produced by the crop
seeds may directly inhibit cold acclimation.

Reports of cold hardiness studies indicate that we cannot assign
any specific safe temperature minimum to a tree at any given time.
Duration of exposure to the temperature minimum must be considered.
Injury increases with the length of exposure to cold as the lethal
temperature is approached. Also, repeated freezing and thawing has
an amplifying effect on injury,

A given level of cold hardiness is subject to change toward
less hardiness if the day or nighttime temperature gets much above
freezing. Just how much hardiness is lost undoubtedly depends on
length of exposure and how high the temperature goes, but these
relationships have not been clarified. In peaches it appears that
deacclimation (loss of the acclimated condition) is minimal during
the rest period, but can take place very rapidly on exposure to a
few hours of warm temperature any time after the rest period is
completed. The rest period is usually completed in late January or
early February in New England peaches.

Pruning in the fall or early winter makes trees more suscepti-
ble to cold injury. Again, an acceptable explanation of why this is
so has not appeared. Early pruning was obviously a major contribut-
ing factor to the trunk injury in some orchards in the 1975-76
winter. At Storrs, the only trees to show trunk damage were those
(18-year-old Jerseyred) that had been heavily pruned in late Novem-
ber and early December. No further pruning was done until early
February. Comparable Jerseyred trees pruned similarly in February
showed no damage. Injured trees lost 50-901 of the bark around the
trunk in the spring of 19 76, These observations indicate the damage
must have occurred during December or January. December temperature
went to zero or lower on two days; Christmas Eve (0°F) and Christmas M
Day (-1°F) at Storrs. In January, 4 subzero readings were recorded:
-1° the 18th, -3° the 19th, -8° the 23rd, and -5° the 24th, In
February the lowest minimum was +5° on the 3rd.

The fall of 1975 was unusual in that it remained quite warm
through the middle of December. The lowest for November was 27°
and daytime highs were over 60° as late as the 21st and 22nd.
December continued the warm trend with 61° Dec. 1st, and 60° the

15th. The only minimums through Dec. 15 that were below 20° were
15° and 18° early in the month.

After the 60° temperature o£ Dec. 15, there was a drop to 16°
on Dec. 17, and minimums remained low for the next 9 days with read-
ings of 20, 7, 6, 10, 17, 17, 0, -1, and 5°. The first snows came
during this period, accumulating to 9" between Dec. 21 and 23. For
the rest of December, January and February, temperature records show
favorable conditions for acclimation. A high of 52° on Dec. 27
cooled gradually and single number temperatures did not appear again
until January 5 and 6. During that 9 day period maximums did not go
above 41°. By January 23, when the winter's lowest temperature (-8°)
was recorded, trees should have been well acclimated. The temperature
fluctuations during January were not great, nor as rapid as in Decem-
ber.

However, trunk injury was associated with pruning done as late
as the 3rd week of January in some orchards. In most years, trees
pruned in the second or third weeks of January do not suffer cold
injury. Since January temperatures in 1976 were not unusual, it
must be supposed that the injured trees were not as well acclimated
as in most years. Non-pruned trees withstood subzero temperatures,
but the hardiness-reducing effect of pruning was sufficient to raise
their critical temperature level into the subzero temperatures
experienced in January. Possibly injury would also have occurred
on trees pruned in February if subzero temperatures had occurred
in February.

The tree tissues that were injured at Storrs, and other orchards
in Connecticut were the bark or cambium of the trunk and lower scaf-
fold limbs. Bark separated from the wood in some cases, and remained
attached in others. In both cases the bark died and decayed in the
spring and summer. On some trees, bridges of live bark remained
between dead areas, connecting across the injured zone. In Connecti-
cut, these injured trees produced a normal crop in 1976, indicating
that the conducting tissue of the wood was not seriously harmed.
Completely girdled trees died during 1977, but some trees with very-
little connecting bark remained alive, and even looked pretty good
except for crop.

Studies of cold hardiness have shown that bark and wood tissue
of acclimated apple trees survive cold temperatures by two different
mechanisms. Acclimated wood tissue is capable of a phenomenon called
deep supercooling. Supercooled water in the protoplasm remains
liquid even when its temperature is far below the normal freezing
point. It is a phenomenon that can also be shown by pure water when
small droplets are dispersed in a low-freezing-point liquid.
Researchers suspect that in the woody stem or trunk tissue, proto-
plasmic water may be somehow isolated from ice nucleation that
occurs outside the cell walls. A temperature is finally reached,
however, at which this protoplasmic water (or the finely dispersed
water droplets in a non-living system) will suddenly freeze to ice.
This temperature is around -40° F for fully acclimated tissue or

-4-

dispersed pure water. Apple trees do not survive where winter
temperatures frequently drop below about -40° because below that
temperature ice forms in the living wood cells, causing death.

Apple bark, cambium, and bud tissues, do not depend on deep
supercooling. Investigations have shown that these tissues survive
our winters by moving the freezable protoplasmic water outside the
cells to sites where ice formation does no apparent damage. As the
temperature drops below freezing, ice begins to develop in cracks
in the bark, in intercellular spaces, and between bud scales. This
creates a vapor pressure gradient favoring movement of protoplasmic
water toward the ice. The protoplasm becomes dehydrated rather than
freezing, but considerable dehydration does not harm acclimated
tissue. Experimentally, apple bark, cambium, and bud tissues have
been subjected to temperatures more than 100°F below zero without
injury if the temperature drop is not too rapid. The ability of
these tissues to survive is thought to be limited by the rate at
which water can move out of the protoplasm when temperature drops.

If the temperature drops at a rate of degrees per minute these
tissues can be injured by ice formation within the cells even when
fully acclimated. Air temperature drop in nature is normally at
rates of degrees per hour. The temperature fall on the morning of
December 17, 1975 was about ICF in 5 hours (2°F per hour;) between
26° and 16°F.

If the bark and cambium had been fully acclimated on December
17, 1975, we would not expect that intracellular ice could have
formed, in response to the 2° per hour temperature drop. On the
other hand, the 60 °F temperature of December 15 may have deaccli-
mated the tissue. Then the tree would have had only 5 or 6 hours
of exposure to temperatures below 28°F before the 16° temperature
occurred. Recall that a period of days or weeks at sub-freezing
temperature is needed to induce much acclimation.

Temperatures of bark and cambium tissues apparently do some-
times drop at rates faster than water can move out to safe freezing
sites. It can happen in winter v>?hen air is calm and well below
freezing, and the south, or southwest, side of the tree trunk is
exposed to direct low angle sunshine. Tissue temperature can go
to 70 or 80°F under these conditions. When the sunlight is suddenly
cut off by shading, or sunset, the bark temperature returns to
ambient air temperature very quickly. This sometimes results in
bark or cambium kill on the south or southwest side of tree trunks.
It can be prevented by applying a reflective white latex paint to
the trunks.

Knowledge of the relative hardiness of different tissues at
different times of the year can be helpful when trying to determine
when injury might have occurred, if it is discovered much later.
It has been shown that sapwood is the hardiest tissue in the early
fall. But by midwinter, cambium is the hardiest tissue, bark tissue
is slightly less hardy, and sapwood is least hardy.

Discovery of blackheart in the sapwood, without any bark or
cambium injury would indicate severe midwinter cold. Many New
England Baldwin trees have blackheart as a result of the extremely
low temperatures of 1933-34. Finding injured cambium or bark but
normal sapwood points to fall or early winter cold. Injury to both
cambium and sapwood could result from unusually low temperature at
any time in trees that were not well acclimated. Southwest trunk
injury could also occur at any time in the winter months.

In summary, the factors that seem to have been most involved
in the 1975-76 winter injury seen in Southern New England were:
(1) a mild fall encouraged late growth activity, and discouraged
acclimation; (2) warm temperature in mid-December may have deaccli-
mated the tissue just prior to a period of low temperatures; (3)
a very heavy 1975 crop load on some trees limited the development
of cold hardiness; (4) pruning of trees prior to occurrence of
critical temperatures reduced the trees' ability to withstand cold.

From the experience of 1975-76, and other winters, it should be
reasonable to conclude that pruning before late February entails risk
any year, but when conditions have not been favorable for development
of cold acclimation by late December, early pruning is especially
hazardous. Growers should learn to recognize seasons in which early
pruning must be avoided. A suggested guide, until something better
is developed, might be:

(1) Don't prune before Christmas, because mild temperatures
are likely to occur before then that can deacclimate the
trees.

(2) Keep a record of minimum and maximum temperatures, begin-
ning November 1. Delay pruning until February if there
have been 2 5 days with minimums of 28°F or lower by
December 25.

(3) Don't prune within 10 days following maximums of 55°F or
more that occur before Christmas.

(4) Leave for late February and March, the pruning of all
trees that bore especially heavy crops and those that
were weak or had reduced leaf surface for any reason.

Use of a guide such as this will not eliminate the possibility
of injury due to unusual temperature extremes, but it should minimize
the risk of cold injury that is associated with pruning.

EVALUATION OF ALAR AND ETHREL ON THE COLD HARDINESS
OF 'MCINTOSH' AND 'DELICIOUS' APPLE TREES

William W. Jenney and Bertie R. Boyce
Department of Plant and Soil Science
University of Vermont
Burlington, Vermont

It is well known that the development of cold hardiness in
plants is primarily a function of the type or variety of plant and
the weather conditions, especially temperature and day length, during

the autumn. The degree of hardiness that a plant develops, however,
may also be modified to a limited extent by other factors such as
cultural practices or use of various plant growth regulators.

Although Alar and Ethrel are used as growth regulators in many
apple orchards, we have little knowledge of whether or not their use
influences the cold hardiness of the trees. The purpose of this
investigation was to determine if the hardiness of bearing-age trees
is either increased or decreased by their use.

The work was carried out over 2 seasons, from June, 1975 to
March 1977, on 30 Mcintosh and 30 Delicious trees located at the
University of Vermont Horticultural Research Center. All trees were
on M. 7 rootstocks, approximately 25 years old, and uniformly vigor-
ous .

Five Mcintosh and 5 Delicious trees were used for each of 6
treatments. The treatments were: (1) unsprayed controls; (2) Alar
at 2#/100 gal applied in early June; (3) Alar at 2#/100 gal applied
in early August; (4) Ethrel at 2-1/2 pts/100 gal applied about 10
days prior to normal harvest; (5) the June Alar application plus the
Ethrel application, and (6) the August Alar application plus the
Ethrel application.

Terminal shoots collected at monthly intervals from August to
March 1975-76 and again in 1976-77 were frozen in the laboratory to
several different temperatures and the amount of injury occurring
was measured by determining the electrolyte release from the injured
cells.

As expected, the Mcintosh shoots were injured less by freezing
than were the Delicious shoots; however, very few significant differ-
ences in hardiness between the treated trees and controls were found
with either variety. Slightly less injury occurred in both varieties
at mid-winter of the first year when trees had been treated either in
June or August with Alar. The same treatments brought about a slight
increase in injury when the shoots were frozen in March. Ethrel
appeared to have even less influence than Alar in altering the hardi-
ness of apple shoots. Shoots of Ethrel-treated trees had slightly
less injury than the controls when frozen in November, 1976, and
slightly more injury when frozen in March.

-7-

Although statistical differences in shoot hardiness were occa-
sionally detected as a result of the application of these materials,
the differences were small and of little practical significance.
Based,on these 2 years' data, it appears that Alar and Ethrel had
only limited and erratic effects in altering the cold hardiness of
Mcintosh or Delicious shoots, and the use of these materials probably
does not significantly increase or decrease the possibility of low
temperature injury, even though they do alter the physiology of the
tree .

****************

QUINCE RUST ON APPLE

Daniel R. Cooley, Extension Technician
Plant Pathology
University of Massachusetts

Quince rust (caused by the fungus Gymno sporangium clavipes ]
appeared as a problem on Red Delicious in Massachusetts this past
season. It was also present in the Hudson Valley area of New York.
Generally, the disease is of little importance, but outbreaks can
cause serious damage.

Quince rust shows on the fruit as a sunken, dark green, mis-
shapen area near the calyx end. The disease often extends into the
fruit, discoloring areas as far as the seed cavities. Fruit may also
redden prematurely. The disease seldom affects apple leaves.

Quince rust is related to cedar apple rust. Both fungi require
two hosts in order to reproduce. During July and August, infections
on apples (or on related plants, such as quince, hawthome, amelan-
chier or crabapple) produce spores. Wind blows these spores to the
next host plant, the red cedar or native juniper, where infections
are started. After 2 years, wet weather in May or June will release
spores from the juniper and red cedar infections. These spores will
infect apple or related plants, and the cycle repeats itself.

Removing red cedars and other junipers located within 2 miles
of the orchard makes rust control much easier. Widening the juniper-
free area to 4 or 5 miles can completely control rusts. However, in

most cases, it is more practical to apply a fungicide. A grower
should note that while some scab fungicides also provide good rust
control (Dikar, manzate, polyram) , other good scab fungicides do not
control rust (benomyl, captafol, captan, dodine, glyodin) . Other

fungicides give good rust control, and fair to poor scab control
(ferbam, Niacide-M, thiram, zineb)*. Fungicides to control quince
rust and cedar apple rust should be applied from the time of pink
buds to the third cover.

-8-

* A listing of the activity spectrums of apple fungicides is avail
able from the Plant Pathology Department, Fernald Hall, University
of Massachusetts, Amherst, MA 01003.

****************

SPIDER MITE SUBSTANCES INFLUENCING SEARCHING BEHAVIOR
OF THE MITE PREDATOR, A mblyseius fallacis , ON APPLES

Robert G. Hislop, Nancy Alves, and Ronald J. Prokopy
Department of Entomology, Fernald Hall
University of Massachusetts

In the preceding two issues of Fruit Notes , we described our
laboratory and field results on effects of various orchard spray
materials on the survival and reproduction of Amblyseius fallacis ,
the most important mite predator in Massachusetts commercial apple
orchards. We observed that even in orchards using materials com-
paratively safe for /u_ fallacis , this predator's performance was
often less effective against red mites than against two-spotted
mites. We suggested that factors such as late-season competition
from other predators might partially explain this difference. Furthe
observations, however, suggested that this reduced effectiveness
against red mites might also be due to particular early-season habits
of A^ fal lacis which could possibly allow red mites to build up
uncheclceH^ in the Spring and early Summer.

Adult A. f allacis females spend the Winter in orchard surface
litter. In'~Spring, warming temperatures bring them out of their
Winter shelters up into the ground cover vegetation where they feed
on two -spotted mite prey. In early Summer, they invade the apple
tree foliage in search of red and two-spotted mites. Because two-
spotted mites (but not red mites which were introduced here from
Europe) are believed to be the native prey of A_^ fallacis , we theo-
rized that perhaps this predator had evolved certain capabilities
allowing it to locate two-spotted mites more efficiently than red
mites. If this were true, and A^ f allacis could more readily locate
two- spotted mite infestations, particularly in the orchard understory
then it would seem that A^ f allacis might become preoccupied feeding
on this host. Red mites could then escape predator detection while
building up in the trees.

The purpose of this research described here was to examine the
possible influence of physical and chemical substances deposited by
red and two-spotted mites on the host searching behavior of A. fallaci
As we will show, such behavior- influencing substances do in Tact exist
At the conclusion of thie article we outline how, in the future,
spray applications of the synthetic equivalents of these substances
to apple trees might enhance the ability of A_^ fallacis to better con-
trol red and two -spotted mites.

-9-

In our first experiment we allowed equal numbers of red and two-
spotted spider mites to infest separate 1/2 inch diameter apple leaf
discs for 2 days, after which all spider mite prey (including eggs)
were removed. Each leaf disc was then placed in a simple, single
choice observation chamber. We then placed a single starved A.
f allacis female at the edge of the chamber and allowed it to enter
and leave the disc at will. Data and observations were recorded
over a ten-minute time period. The results (Table 1) show that A.
f allacis females spent an average of 312 seconds per visit on discs
having previous two-spotted mites compared with only 58 seconds per
visit on discs having no previous prey (an approximate 5-fold dif-
ference) and 156 seconds per visit to discs having previous red mites
(a 2-fold difference). These data strongly suggest that both species
of spider mites deposit substance(s) that function to arrest host
searching Aj_ f allacis , and that the substance (s) deposited by two-
spotted mites was more than twice as active as that deposited by red
mites. In this experiment we noticed that a large amount of silk (a
white thread-like material very similar to the sort of silk spun out
by spiders) was left behind by the two-spotted mites. We suspected
that this silk might be playing a role in the observed behavior of
A. f allacis .

TABLE 1. FREQUENCY AND LENGTH OF VISITS BY A^ f allacis FEMALES TO
APPLE LEAF DISCS HAVING PREVIOUS PREY. (20 replicates)

Avg. no. A. fallacis Avg. time

visits per apple (seconds) per

Previous prey leaf disc visit on disc

Two-spotted Mites 1.5 312

European Red Mites 2.6 156

None (check 3,4 58

Therefore, in our second experiment, we examined the possible
influence of two-spotted mite silk on the searching behavior of A.
f allacis . We manually placed the silk spun by 50 two- spotted mites
over a 24-hour period onto 1/2 inch diameter filter paper discs. Each
disc was placed in the observation chamber with a single starved A.
fallacis female and data recorded as before.

The results (Table 2) show that host searching A^ fallacis females
spent 142 seconds per visit on discs containing two- spotted mite silk,
compared with 12 seconds per visit on discs having no silk (a 12-fold
difference). This result strongly suggested that physical and/or
chemical properties of two-spotted mite silk function to arrest host
searching A. fallacis females.

-10-

TABLE 2. FREQUENCY AND LENGTH OF VISITS BY A^ fallacis FEMALES TO
FILTER PAPER DISCS HAVING TWO-SPOTTED MITE SILK. (20
replicates)

Condition
of disc

Avg. no. A^ fallacis
visits per disc

Avg. time (seconds)
per visit on disc

With silk
Without silk

3.5
6.1

142
13

In our final experiment reported here, we ex
influence of solely chemical substance (s) deposit
mites on the host searching behavior of /u_ fallac
spotted mites on 1/2 inch diameter filter paper d
after which all mites and eggs were removed. We
discs in one or another of four different types o
water, methanol, chloroform, and hexane. The was
were then centrifuged at high speed to remove any
such as silk, that might influence /u_ fa.llacis ho
We reapplied each extract to a series of fresh fi
each of which was dried and placed in the observa
single starved Aj_ fallacis female. The searching
females was then recorded over a ten-minute perio

amined the possible
ed by two-spotted
is . We placed two-
iscs for two days,
then washed ten such
f chemical solvents:
hings (= extracts)

physical substance
St searching behavior.
Iter paper discs,
tion chamber with a

behavior of the
d.

The results (Table 3) show that host-searching A^ fallacis females''
visited discs treated with the methanol extract an average of 8.2
times, nearly three times more frequently than they visited control
discs treated with solvent alone (= 3.3 visits). Although the average
length of each visit was approximately equal on each disc type, the
length of time between visits to discs treated with the methanol
extract was only 34 seconds, less than 1/3 the time between visits to
check discs (= 112 seconds) . These data, coupled with our observations
suggests that host-searching A^ fallacis females were stimulated to
repeatedly return to discs treated with methanol-extracted chemical
substances deposited by two-spotted mite prey.

TABLE 3. FREQUENCY AND LENGTH OF VISITS AND RETURNS BY A. fallacis

FEMALES TO FILTER PAPER DISCS TREATED WITH CHEMTCAL EXTRACTS
OF SURFACES PREVIOUSLY VISITED BY TWO-SPOTTED MITE PREY.
(20 replicates)

Avg . No . A_^ fallacis
Solvent visits per disc

Average time (seconds)
per visit on disc between visits

Extract
3.6

Control
5.3

Extract
32

Control
26

Extract
54

Control

Chloroform

Hexane

4.1

3.9

118

Water

7.4

5.9

Methanol

8.2

3.3

112

-11-

We have thus discovered in these experiments two sorts o£
behavioral reactions of host searching A^ fallacis females while
in the neighborhood of substances deposited by red and two- spotted
mite prey: (1) stimulated searching activity in the vicinity of
extracted chemical substance (s) , and (2) arrestment in the presence
of two-spotted mite silk. In nature, it is likely that such chem-
ical substance(s) secreted by red and two-spotted mites, is utilized
by A^ fallacis adults as a cue aiding in more rapid and better detec-
tion of nearby areas infested by prey. Contact with the physical
structure of the silk of the prey slows down the host searching
activity of A. fallacis adults, arresting them in the immediate locale
of an indiviHual prey. These results also support our hypothesis
that A. fallacis could become preoccupied for relatively long time
perio3¥ searching within areas of two-spotted mite infestations,
thereby having the effect of preventing the predator from exploring
new areas harboring other hosts such as red mites .

Chemical substances that are deposited by prey and that influence
the host searching behavior of predators such as A.« fallacis are
called "kairomones". Eventually, they could be of significant value
to pest management programs. For example, if one were to identify
and synthesize the kairomone secreted by two-spotted mites and spray
it on apple trees together with artificial alternate food substances
for A^ fallacis , the result could possibly be greater retention of
A. fallacis on the apple foliage during times when natural prey densi-
ties are low. Such artificially maintained populations of A^ fallacis
could function to "guard" against possible spider mite outbreaks .

FRUIT NOTES INDEX FOR 1978

(This index of major articles has been prepared for those who keep
a file of Fruit Notes . The number in parenthesis indicates the
pages on which the item appears.)

January/February - Vol. 43(1)

Varieties of Peaches for Massachusetts (1-3)
Trends of Michigan Tree Fruit Industry (Part II) (3-7)
Shelf Life of Pesticides in Common Use by Fruit Growers (8-9)
European Apple Sawfly: Biology and Development of an Adult
Monitoring Trap (9-12)

March/April - Vol, 43(2)

Varieties of Raspberries and Blackberries for Massachusetts

(1-2)
Partial Budgeting of Management Alternatives for Fruit

Growers (3-7)
Trends of Michigan Tree Fruit Industry (Part III) (8-10)
Tarnished Plant Bug on Apple: Damage and Monitoring Traps

(10-14)

12-

May/June - Vol. 43(3)

Apple Pollination Comments (1-3)

Factors Affecting Shape of Apples and Increasing Their

Length with Promalin* (4-7)
Nutritional Problems and Suggestions for Fertilization of

Apple Trees in 1978 (7-13)
Naphthaleneacetic Acid (NAA) for Tree Training (13-15)
Alternate vs. Every Middle Spraying for Apple Pests in

1977 (15-19)

July/ August - Vol. 43(4)

Factors Affecting Nutrient Content of Apple Foliage (1)

Late Summer Fertilization of Strawberries (2)

New Herbicide for Blueberries (3)

Use of Creosote to Prevent Deer Damage in Orchards (4)

Influence of Pesticides on Spider Mite and Predator

Abundance in Massachusetts Apple Orchards -- 1977

Results (5-8)
Apple Tree Response to Summer Pruning (8-12)
The Effect of Summer Pruning of Mcintosh Apple Trees on the

Calcium Nutrition and Postharvest Quality of the Apples

(13-14)

September/October - Vol. 43(5)

Harvesting and Storing Apples: A Time for Observing Details

(1-5)
Bruising of Apples After Packing (5-7)

Controlled Atmosphere Storage Safety Precautions (8-10)
Chokecherries : How to Recognize and Get Rid of Them (11-13)
Miscellaneous Information on Orchard Mouse Control (13-14)
Laboratory Toxicity of Pesticides and Growth Regulators to

Amblyseius fallacis , An Important Spider Mite Predator

in Massachusetts Apple Orchards (14-18)

November/December - Vol. 43(6)

Winter Trunk Injury to Apples (1-5)

Evaluation of Alar and Ethrel on the Cold Hardiness of

'Mcintosh' and 'Delicious' Apple Trees (6-7)
Quince Rust on Apple (7-8)
Spider Mite Substances Influencing Searching Behavior of

the Mite Predator, Amblyseius fallacis , on Apples (8-11)

****************

NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL
INJURY OR PROPERTY DAMAGE.

Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whaley
Director
;ooperative Agricultural Extension Work
Acts of May 8 and June 30, 1914

Official Business
'enalty for Private Use, $300.

POSTAGE AND FEES PAID

U.S. DEPARTMENT OF

AGRICULTURE

AGR 101

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FRUITpr

NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 44 (No. 1)

JANUARY /FEBRUARY 1979

TABLE OF CONTENTS

Varieties of Strawberries for Massachusetts
Pruning Macspurs
Pomological Paragraph

Stub pruning
Pruning Peach Trees

Control of Water Sprouts and Suckers with Tree-Hold*
U.S. Apple Exporters Expect Another Good Year

Following Record Showing in 1977/78
Integrated Management of Apple Pests in Massachusetts-

1978 Results: Insects

ERRATUM IN NOVEMBER/DECEMBER ISSUE

An error that should be corrected occurred on page 5 of the Nov./
Dec. issue of Fruit Notes . Item 2 of the suggested pruning guide states
"Delay pruning until February if there have been 25 days with minimums
of 28°F or lower by December 25". This should have read "Delay pruning
until February if there have not been 25 days with minimum of 28°F or
lower by December 25".

****************

VARIETIES OF STRAWBERRIES FOR MASSACHUSETTS

James F. Anderson
Department of Plant and Soil Sciences

Varieties

Recommended for

Harvesting Season

Ear li dawn

Darrow

Earliglow

Sunrise

Midland

Holiday

Raritan

Midway

Catskill

Redchief

Guardian

Garnet

Sparkle

Delite
Vesper

T = Trial

C
T
T
C

C
5 H

H
H
H

a H

5 H
^ H
T
C

H = Home garden

Very early

Early

Early-midseason

Midseason

Mid-late

Mid- late

Late

Very late

C = Commercial

Varieties so marked are not necessarily equally adapted to all
sections of the state.

Earlidawn

Darrow

Earliglow

Sunrise

Variety Notes

The fruits are of medium size and of fair to good
flavor. The plants are productive and of moderate
vigor. Earlidawn is not recommended where red stele
is present.

The fruits are medium to large, firm, glossy and have

a deep red color. Primary berries tend to be rough.
The plants are moderate in fruit production, vigor

and runner production. Darrow is highly resistant to
red stele and partially resistant to Verticillium wilt.

The fruits are medium to large, firm, have a uniform,
symmetrical shape and medium to dark red color. The
flavor is very good. The plants are productive, make
a good bed and are highly resistant to red stele and
Verticillium.

The berries are medium in size, glossy bright red, firm
and have a symmetrical conic shape . The plants are
vigorous, fair in production and resistant to red stele
and Verticillium.

-2-

Mid land The berries are large, firm, dark red and have very
good flavor. The early fruit tends to be coarse.
Midland is susceptible to both red stele and Verti-
cillium.

Holiday The berries are large, attractive, glossy, medium
to dark red, very firm and fair to good in flavor.
The plants are vigorous, make a good bed and are
productive. Holiday is susceptible to red stele but
had partial resistance to Verticillium.

Raritan The berries are very attractive, bright red, glossy,
firm, medium to large and have very good flavor. The
plants form a good bed and are productive. Raritan
is susceptible to both red stele and Verticillium,

Midway The berries are of good size, a deep red color, glossy

and very good in flavor. The plants are vigorous,

productive and resistant to red stele. Midway is
susceptible to Verticillium.

C atskill The berries are large, have a good strawberry flavor.

The berries have a tender skin and rate only fair in

firmness. The plants are very productive and are
resistant to Verticillium but are susceptible to red
stele .

Redchief The berries are medium to large, attractive, firm and
have good flavor. The plants are vigorous and pro-
ductive. Redchief is highly resistant to red stele
and intermediate in resistance to Verticillium.

Guardian The berries are large, glossy and light red in color.

The primary berries tend to be rough. The berries

are firm and have good flavor. The plants are vigor-
ous and productive. Guardian is highly resistant to
both red stele and Verticillium.

Garnet The berries are large, attractive, moderately firm

and have good flavor. The plant is vigorous, forms

a good bed and is productive. Garnet is susceptible
to both red stele and Verticillium.

Sparkle The berries are medium to large, firm, dark red and

have very good flavor. Berry size tends to decline

rapidly. The plants are vigorous, productive and
have partial resistance to red stele but are suscep-
tible to Verticillium.

Delite The berries are medium to large, long conic to long

wedge in shape, bright red, glossy, firm and have good

flavor. The plants are vigorous, productive and are
highly resistant to both red stele and Verticillium.

Vesper

The berries are very large, attractive, moderate in
firmness and good in flavor. The plants are vigorous
and productive but are susceptible to both red stele
and Verticillium.

****************

PRUNING MACSPURS

Department

William J. Lord
of Plant and Soil

Sciences

On bearing Macspur trees, it is common to find weak scaffold
limbs with few lateral branches. Scaffold limbs of this type have
small potential bearing area. Branching can be induced on these
limbs with stubbing cuts into 2- or 3-year-old wood.

Figure 1 illustrates the response to such a stubbing cut. On
this figure, the arrow points to where a branch on Macspur was stubbed
during the previous dormant season. Note the vigorous upright growth
during the following growing season that was stimulated by the cut.
The branch in the upper-right-hand corner is one that possesses inade-
quate lateral branching.

During the dormant season following stubbing, the vigorous vege-
tative growth behind the stubbing cut, portrayed in Figure 1, should
be selectively pruned leaving only those which have the potential to
become horizontally-oriented lateral branches. This is illustrated
in Figure 2 .

Don' t make stubbing cuts unless they are needed to induce branch-
ing, reduce the length of limb, or stiffen unheaded limbs, because it
has been shown with Delicious that stubbing can convert fruiting spurs
into non-fruitful, vigorous shoots.

Figure 1

Figure 2

****************

-4-
POMOLOGICAL PARAGRAPH

Stub pruning . We haven't mentioned stub pruning since it was discussed
in the February, 1964 issue of Fruit Notes . However, while pruning
branches on the windward sides of Delicious trees planted on a windy
site this past winter the practice was brought in mind. We know that
branches on the windward side are apt to "hug" the leader until crop-
ping holds them down. Leaving extra limbs on the windward side of
trees on windy sites will help keep the branches more horizontal because
of competition. However, to keep from restricting the central leader
and/or inhibiting the development of desirable scaffold limbs, do stub
pruning. Stub pruning involves reducing the length of undesirable limbs
instead of removing them. Many of the stubbed branches will have to be
removed or again restricted during the next pruning season.

****************

PRUNING PEACH TREES

William J . Lord
Department of Plant and Soil Sciences

Pruning peach trees correctly is one of the most important opera-
tions in peach growing because Valsa canker, winter injury, and limb
breakage are problems associated with poor pruning practices.

Peach trees may be pruned as either open center or modified leader
type trees. The open center system consists of 3 main scaffold limbs
arising at approximately the same point on the trunk. The modified
leader type tree has 3 to 5 branches vertically spaced 4 to 6 inches
apart along the trunk, with the modified leader also carrying side
branches. The writer prefers the modified leader type tree, the prun-
ing of which is described below, because it is less time consuming to
train during the formative period and in our experience, results in
less limb breakage during periods of high winds. Following a wind-
storm in August, 1976, damage to open-center trees in one orchard was
so severe that the grower had to remove them, whereas trees trained
as modified central leader trees were retained.

P runing at planting : A 1-year-old peach tree as it comes from the
nursery normally has several side branches. After the tree is set,
all branches within 18 inches of the ground should be removed. Any
narrow-angled side branches should be cut off. Then, 3 or 4 branches
which come out at wide angles, vertically spaced about 6 inches apart,
should be saved for main scaffold branches. All other limbs should be
cut off flush with the trunk. The leader should be cut back to the
top-most side branch and the lateral branches should be cut back to
short stubs, 2 to 4 inches long, with each containing 1 bud.

Pruning during the formative period : Delay pruning of both the young
and bearing tree until late spring (near bud swell) . After pruning,

spray the trees with a fungicide before a rain occurs to help prevent
or reduce damage from Valsa canker. (Information on fungicides for
Valsa canker control can be obtained from your County Extension Ser-
vice.) Since Valsa canker is frequently associated with poor pruning
practices and winter injury, other control measures include avoiding
or eliminating narrow crotches, making pruning cuts so as not to leave
stubs, and avoiding late growth.

Pruning during the formative period consists of making the final
selection of scaffold branches. These branches should be chosen after
the first season's growth. Most v/ill be the same branches that were
selected originally, with some slight readjustments. Subsequent prun-
ing should develop an open bowl -shaped tree by removing branches that
tend to grow inward and those which are growing straight up through
the center of the tree. Head back slightly only those selected scaf-
folds where growth has exceeded 30 inches with little or no branching.
On scaffolds which have made less than 30 inches growth with several
side branches, cut off all but 2 or 3 well-spaced side branches. Lat-
erals on a scaffold branch which will grow out and slightly up from
left and right are most desirable. Those which tend to grow towards
.the ground should be removed. All branches which arise from the
trunk, other than scaffolds, should be removed.

From the second to the fourth year, cut off annually those branches
which interfere with the growth of the scaffold limbs but avoid severe
pruning, which will delay the time when the tree will start to produce
a profitable crop.

P runing bearing trees : When pruning bearing peach trees, keep in mind
that peaches are borne laterally on shoots that grew the previous year.
Therefore, the stimulation of 1-year shoot growth by fertilization and
pruning is essential for maximum yields of fruit. On a vigorous 1-year
shoot, usually 3 buds will be produced at each node. The 2 plump out-
side buds will be flower buds and the smaller bud in the center will be
a leaf bud. On less vigorous shoots there may be but 1 flower bud and
a leaf bud on a node .

In pruning a bearing tree the following branches should be removed:

1. Those which are broken or diseased.

2. Those which are slender and weak especially on the inside

of the tree.

3. Those which grow toward the center or straight up.

4. Those which grow doxmward so as to interfere with mowing or
cultivating equipment.

After these branches are removed, it may be necessary to thin out
a few of the more vigorous branches where they are too numerous. "Leggy"
branches (those which grow out for a considerable distance without
branching) need to be headed back in order to induce the development
of side branches nearer the trunk. To overcome the peach tree's growth
habit of producing bearing wood further and further from the trunk,
retain a few young branches on the inner parts of the tree. These
brancher: should be located so that they will subsequently replace older

-6-

wood. To keep the tree at a convenient height, head back upright
branches to an outward growing lateral branch when they reach a dis-
tance of approximately 8 feet from the ground.

Pruning Winter- Injured Trees : Peach trees may suffer winter injury
from low temperatures by killing of the flower buds, and by killing of
the wood. Under Massachusetts conditions, the critical winter tempera-
ture for the killing of flower buds is about -15°F. The exact tempera-
ture at which flower buds will be killed depends upon the variety, as
some are more hardy than others. The extent of flower bud injury can
be determined by cutting several buds and noting if they are bldck in
the center. If all of the buds are killed, an opportunity is provided
to reduce the proportion of old wood without affecting the crop since
there would be no crop the following summer anyway. This will tend to
stimulate the development of new growth nearer the trunk.

With more severe temperature (-20°F or lower) the wood may be
injured in addition to the buds. This condition is indicated by the
inside of a branch turning dark brown or black. When this condition
exists, it is best not to prune the tree until after growth starts.
Then, only weak shoots on the interior of the tree and dead branches
ishould be removed since the tree will need every healthy leaf to help
recover from the winter injury.

****************

CONTROL OF WATER SPROUTS AND SUCKERS WITH TREE-HOLD*

William J. Lord and Duane W. Greene
Department of Plant and Soil Sciences

Water sprouts, which generally are removed to maintain tree form
and prevent shading, are particularly troublesome on standard-type
Delicious and following heavy pruning. Unfortunately, their removal
becomes more time consuming in succeeding seasons because of the pro-
liferation from the stubs created by pruning. Sucker growth from the
trunks and roots of mature seedling trees and in plantings of M.7 and
M,7A is a serious problem in Massachusetts. Suckers are costly to
remove, increase in number annually, provide mouse cover, and are a
haven for insects and diseases.

We now have a 24-C State Registration for Special Local Needs for
Tree-Hold Sprout Inhibitor A-112 (Amchem Products, Inc., Ambler, PA)
for the control of water sprouts and suckers in apple and pear orchards
in Massachusetts. This formulation contains 15.11 ethyl ester of
naphthaleneacetic acid and is equivalent to 13.2% naphthaleneacetic
acid by weight (1 lb/gal) . This formulation must be diluted before
use, with either water or white interior latex paint.

* Trade Name

-7-

Tree-Hold diluted in a combination o£ water and water-base,
interior-grade, white latex paint has given good control o£ water
sprouts at our Horticultural Research Station in Belchertown. However,
more experience is needed to determine its effectiveness when used
alone or in combination with herbicides for the control of suckers
because failure of Tree-Hold to control dense sucker growth under
mature trees has been reported. Thus, we suggest the use of Tree-Hold
on a trial basis only for sucker control.

Mixing for Water Sprout and Sucker Control

For the control of water sprouts use 10 fluid ounces (2/3 pt) of
Tree-Hold and make up to a volume of 1 gallon with a combination of
water and interior-grade latex paint. The latex paint "marks" the
treated areas and makes the mixture more viscous, thus restricting the
NAA to the treated area. It has been our experience that at least 4
pints of latex paint should be used in each gallon of treating solution.
Be sure to use an interior-grade latex paint and one that does not con-
tain a mildewcide.

For spraying suckers on a trial basis, mix 10 fluid ounces of Tree-
Hold with sufficient water to make 1 gallon of spray mixture. Eight
gallons of Tree-Hold are required for 100 gallons of spray.

Control of Water Sprouts

Prune water sprouts and then apply Tree-Hold mixture thoroughly
over the cut surfaces. It can be applied with a paint brush or a small
compressed air sprayer. We found that a 1-1/2 gallon compressed air
sprayer with a 12-foot hose worked well, and that attaching a sponge
to the nozzle was useful for swabbing the mixture on pruning cuts. The
treatment can be applied anytime weather permits before growth starts
in the Spring. Areas where pruning cuts have been made should be
covered thoroughly, but drip on to other parts of the tree should be
avoided. The Tree-Hold mixture can kill buds . Be sure to follow the
label .

Control of Suckers

Prune the suckers during the dormant season. The Tree-Hold mix-
ture can be sprayed on the stubs during the dormant season or when the
new shoots from the suckers are 6 to 12 inches in height. However, the
most effective timing is when the suckers are actively growing. Since
the Tree-Hold mixture contains 10,000 ppm NAA, the label restricts its
use from bud swell through 4 weeks after petal fall to eliminate the
possibility of fruit thinning and leaf damage. Therefore, the Tree-
Hold mixture should be sprayed in late-June to mid-July when the suckers
are 6 to 12 inches in height. Coverage should be thorough.

The Tree-Hold mixture is too expensive to apply as a band applica-
tion under the trees. Since the population of suckers is generally
more dense near the trunk and very troublesome inside wire mouse guards,
the spray may be limited to these areas using a compressed air sprayer,
a weed sprayer with an air gun, or a weed sprayer and boom with a trunk-
directed nozzle.

Maintain low spray pressure to avoid drift of the Tree-Hold mix-
ture. Spray on tree trunks is of no concern but drift onto scaffold
limbs will damage foliage and fruit. Although annual sprays of Tree-
Hold mixture may be required, the number of suckers should be gradually
reduced. It is of interest to note that researchers in New York State
reported in 1978 that 3 consecutive annual applications of Tree-Hold
has had no harmful effect on tree growth or productivity.

Summary

Tree-Hold Sprout Inhibitor A-112 is a useful chemical tool for
the control of water sprouts and suckers in our apple orchards. We
are reasonably sure of its effectiveness for water sprout control but
need much more experience with its use on suckers. The new registra-
tion will allow growers to evaluate the effectiveness of Tree-Hold for
sucker control under a variety of conditions. Grower experiences with
Tree-Hold for sucker control will add to the information currently
being obtained at our Horticultural Research Center and by James
Williams, Regional Fruit Specialist in Northeastern Massachusetts.

****************

U.S. APPLE EXPORTERS EXPECT ANOTHER GOOD, YEAR
FOLLOWING RECORD SHOWING IN 1977/78

Gilbert E. Sindelar, Director
Horticultural and Tropical Products Division
Foreign Agricultural Service
U.S. Department of Agriculture
Washington, D.C. 20250

After a banner 1977/78 season, U.S. apple exporters are prepar-
ing for another good year in 1978/79. More normal crops in major
markets of Western Europe following shortfalls last season conceiv-
ably could keep U.S. apple exports from reaching the record sales of
$66 million achieved in 1977/78 (July-June). But sales promise to
be brisk as markets in Latin America, the Middle East, Far East, and
other areas are developed further.

Another bumper U.S. crop -- estimated at 3.3 million metric
tons, the same as last year's -- will allow ample supplies for export
while intensifying pressure to sell abroad. Moreover, the crops are
abundant in traditional exporting areas such as the Pacific North-
west, New England, and eastern New York State.

The status of the U.S. dollar also will have a bearing on U.S.
trade. Prior to its recent strengthening, the U.S. dollar was
declining against many currencies of the world. For instance, the

Reprinted from November 13, 1978 issue of Foreign Agriculture
with permission from the author.

British pound in mid-October 1978 was worth about $2.08, compared
with about $1.85 a year earlier.

Given a landed duty-paid price of $12 per carton (42 lb) for
both years, U.K. importers would have paid about ^ 5.77 for U.S.
apples in October 1978 -- some 11 percent less than a year earlier.

Some further examples of the prolonged deterioration in the
value of one U.S. dollar vis-a-vis foreign currencies (as of October
27, 1978) include:

October

1977

1978

f2.4

fl.9

F2.2

F1.5

DM2.2

DM1.8

Nkr5.4

Nkr4.8

S$2.4

S$2.1

M$2.4

M$2.1

Netherlands

Switzerland

West Germany

Norway

Singapore

Malaysia

Currently, it looks as if total U.S. apple exports in 1978/79
could add up close to last season's recent high of 7.9 million car-
tons. Exports in 1978/79 were well above the exceptionally good
showing of the preceding season (1976/77), when 6.3 million cartons
moved into foreign markets.

At the start of last season, U.S. apple shippers were faced with
a very inviting situation. The important European producers were
then reporting exceptionally small apple crops, which for all Europe
amounted to only about 5 million tons, compared with 6.4 million in
1976. This meant that the United States had an excellent opportunity
to help fill the vacuum on the Continent -- aided by a temporary
reduction in the EC common external tariff on apples from 14 percent
to 6 percent. Additionally, the area's leading producer, France,
was not able to reach distant markets with the same intensity of
former years.

As it turned out, France's apple crop in 1977 was down some 27
percent from the previous year to 1.2 million tons. This decline
greatly limited the country's export potential while opening up new
outlets for the United States in Europe, the Middle East, and other
markets .

Despite loss of shipping time during the first of last season
because of the dock strike on the east coast, U.S. apple exports
went on to score a 25 percent gain in volume and a 57 percent increase
in value over the 1976/77 levels. On a price per carton basis,
export sales to all destinations averaged $8.42 per equivalent 42-
pound carton, versus $6.71 per carton in 1976/77.

This is a far cry from the depressing prospects that confronted
U.S. exporters in the 1960's and early 1970's. Around 1962, for

-10-

£or instance, there were strong signs that the United States poten-
tially could be squeezed out of the world apple market. Plantings
in France and other nearby countries in Western and Eastern Europe
had been exceptionally heavy, portending a future explosion in pro-
duction.

Shortly after the inid-1960's, the explosion hit. Once-viable
U.S. markets in the United Kingdom and Scandinavia collapsed. Pros-
pects appeared bleak to impossible in Latin America and the Far East.

Canada -- like the United States a leading producer and exporter
-- was plagued with similar problems. And, to compound the problem
still further. Southern Hemisphere suppliers such as Australia and
New Zealand began to eye the U.S. late winter through early summer
market with greater interest. They also were having access problems
in Western Europe.

Coinciding with these developments was burgeoning production in
the United States of Red Delicious and other types.

U.S. exports during that time did fall considerably -- averaging
about 2-2.5 million cartons in the late 1960's and early 1970's.
However, a nucleus of grower-shippers simultaneously were searching
for new markets and making quality improvements needed to compete.

Gradually, the situation improved, and today U.S. apple exporters
are shipping reasonably large volumes to the Far East, Latin America,
and the Middle East.

Last year's record showing capped this rebound, as most major
markets came through with larger purchases than in 1976/77.

CANADA -- largest single market for U.S. apples -- was one of
the exceptions to this generally upward trend and probably will show
another slight decline in 1978/79. The current forecast: 2.4
million cartons, against 2.6 million shipped in 1977/78.

However, U.S. sales there last year were larger than expected,
coming in just 300,000 cartons under the unusually high level of
1976/77.

The major limiting factors for 1978/79 will be the slightly
larger Canadian crop and price gains resulting from the weakness of
Canada's currency against the U.S. dollar. The Canadian dollar in
October was worth slightly less than 85 U.S. cents, compared with
93 in August 1977.

In WESTERN EUROPE, U.S. shippers cannot expect to repeat their
strong 1977/78 showing of 1.4 million cartons in view of the 22 per-
cent gain estimated for apple production in 11 key countries there
over the unusually low level of 1977. The current estimate for
1978/79 exports: 600,000 cartons, or some 15 percent above the
522,000 cartons shipped in 1976/77.

-li-

on the positive side, expected output still is some 4 percent
below that of 1976, and crops in the key European producers --
France and Italy -- are off 4 percent and 19 percent, respectively,
from 2 years ago. Italy's crop, in fact, is some 5 percent below
the small outturn of 1977.

LATIN AMERICA (including the Caribbean and Mexico) should con-
tinue its gradual growth as a market for U.S. apples. Exports there
in 1978/79 are forecast at 1.9 million to 2.0 million cartons,
against 1.5 million last year. Shippers will probably at least equal
last year's showing in Mexico and Venezuela -- which together take
about half of all U.S. exports to the region -- and make further
gains in Central America, the Caribbean, Colombia, and possibly
Brazil .

In contrast to diminishing sales opportunities a few years ago,
when France was encroaching on many traditional U.S. markets, Latin
America recently has become an attractive outlet. U.S. shipments
there last year rose 12 percent over the 1976/77 level.

In the FAR EAST AND PACIFIC -- a recent growth market that did
not, however, participate in last year's advance -- sales are
expected to exceed the 1.4 million cartons in 1977/78. A large crop
in the U.S. Pacific Northwest means plentiful export supplies.

Hong Kong should continue to be a high-volume market, with any
plus conditioned in part on currency relationships -- the Hong Kong
dollar has been slightly weaker so far this year. Taiwan, Malaysia,
and Singapore also look better than they did last season, when sales
to Taiwan and Singapore fell significantly.

The region as a whole took 155,000 fewer cartons in 1977/78
than during the previous year. This was the first interruption in
the steady upward trend in sales since 1970, when only 210,000 car-
tons were sold to the Far East.

Exports to the MIDDLE EAST -- which opened up abruptly last
year in response to smaller exports from its traditional supplier,
France -- should at least match the 1 million cartons of U.S. apples
shipped in 1977/78.

France and Italy have long dominated this market and will prob-
ably try to reclaim their traditional shares. However, some trade
sources predict that the United States will exceed last season's
performance in this area by a significant margin.

****************

-12-

INTEGRATED MANAGEMENT OF APPLE PESTS IN
MASSACHUSETTS - 1978 RESULTS: INSECTS

K. I. Hauschild and R. J. Prokopy
Department of Entomology
University of Massachusetts, Amherst, MA 01003

In 1978, the United States Department of Agriculture Extension
Service made monies available for the study of integrated pest
management (IPM) on major crops grown in the United States. We
applied for and received such a grant to study integrated manage-
ment of apple pests in Massachusetts. Although apples rank 6th in
economic importance of agricultural crops in this state, pesticide
usage ranks highest.

Reduced spray programs have been discussed in previous issues
of Fruit Notes [41(1), 41(2), 41(3), 42(3) and 43(3)1. The major
objective of our IPM program was to utilize data obtained from trap
captures of pest adults and other methods (such as sampling leaves
for mites and observing leaf and fruit clusters for aphids and their
predators) to better time, and hopefully decrease, the number of
spray applications aimed against fruit and leaf pests while main-
taining fruit quality.

METHODS

During the growing season of 1978, we scouted 24 orchards in
the four major fruit growing counties (Middlesex, Worcester, Hamp-
den and Franklin) in Massachusetts. Eight orchards were in the IPM
program, wherein we told the growers when and what materials to
spray. Eight were check orchards in which the growers sprayed their
usual program with whatever materials they wished to use. Four
were abandoned orchards which we used to observe presence and rela-
tive numbers of insect pests. Four were alternate-middle vs. every-
middle spray orchards. (We will discuss the 1978 results of the
alternate vs. every-middle program in the next issue of Fruit Notes .)

Every week 10 trees in a 10-acre block in each IPM and check
orchard were scouted for beneficial and pest insects. We looked at
45 leaf clusters and 45 fruits from all parts of each tree for aphids,
aphid predators, other leaf and fruit pests and any injury. Later
in the season (from mid-June to harvest) we took leaf samples which
we brought back to the lab and brushed for predator and leaf-feeding
mites [see Fruit Notes 43(4) ]. We also used visual traps to monitor
tarnished plant bug and European apple sawfly adults in all orchards

[see Fruit Notes 43(1) and 43(2)], pheromone (sex odor) traps for
codling moth and leafrollers, and unbaited sticky red spheres,
sticky j,red spheres baited with ammonium acetate (a food mimic), and
Zoecon AM Standard baited yellow rectangles for apple maggot flies

[see Fruit Notes 41(5) and 41(6)]. In the IPM orchards, decisions

We would like to thank Ted Bardinelli, Kevin Beswick, Victoria
Ciarcia, Sylvia Cooley and Thomas Luippold for their assistance
in this program, as well as the MFGA and participating fruit
growers .

-13-

as to whether or not to spray were made on the basis of trap captures
and visual observations o£ pest and predator insects. Decisions on
all insecticide and aphicide applications were made in the orchard.
Leaf samples for mites were brought back to the lab and processed.
A decision on whether or not to spray for mites was made within 24
hours .

RESULTS

A summary of our 1978 results is given
Average numbers of tarnished plant bug (TPB)
(EAS) , apple maggot fly (AMP) , codling moth
roller (RBLR) and obliquebanded leafroller
in the 8 IPM orchards than in the 8 check or
these higher numbers, fruit injury levels at
infesting insects) averaged 44% lower in the
of 2.6% injury) than in the 8 check orchards
injury). At the same time, the 8 IPM orchar
insecticide sprays aimed at these pests. We
in injury to better timing and avoidance of
cations. In addition, the 8 IPM orchards av
than in the previous 2 years.

in Table 1 (see below) .
, European apple sawfly
(CM) , redbanded leaf -
(OBLR) adults were higher
chards. But, in spite of

harvest (for all fruit-

8 IPM orchards (an average

(an average of 4.81
ds averaged 311 fewer

attribute this decrease
unnecessary spray sppli-
eraged 27% fewer sprays

TABLE 1. Summary of Overall Results - IPM and Check Orchards

TPB

Average Number/Trap

EAS

AMP

RBLR

OBLR

Average

Fruit

Injury

Average No.
Insecticide
Sprays

1978 1976,1977

8 IPM
Orchards

8 Check
Orchards

6.0 5.3 8.5 122.6 166.0 5.5
4.5 4.3 5.7 89.9 98.5 4.5

2.6% 6.7
4.8% 9.6

9.3

Difference +33% +23% +47%

+36% +18% +22%

■44%

-31%

Does not include materials directed solely at aphids (e.g., endosulfan, phosphamidon)
^ TPB = Tarnished Plant Bug

EAS = European Apple Sawfly
AMF = Apple Maggot Fly
CM = Codling Moth

RBLR = Redbanded Leafroller

OBLR = Obliquebanded Leafroller

-14

On the basis of these results, we've calculated (see Table 2)
that with the average reduction in number of insecticide applications
(3) in the IPM orchards, these growers saved between $173.70 and
$322.50 (depending on material and rate) on insecticides alone in
each 10-acre IPM block.

TABLE 2. Savings Attributable
IPM Orchards for the
Comparisons Based on

to Decreased Insecticide Usage in
Two Most Commonly Used Materials.
3 Applications Saved.

Chemical Cost^/Lb. Rate/100 Gal. Savings/A^

Savings/10-A Block
1 Applic. 3 Applic,

Guthion
Imidan

$4.30
$1.93

1/2 lb.

5/8 lb.

3/4 lb.

1 lb.

1-1/4 lb.

$ 8.60
10.75

5.79
7.72
9.65

$ 86.00
107.50

57.90
77.20
96.50

$258.00
322.50

173.70
231.60
289.50

Does not include aphicide use, costs of labor, gasoline or equip-
ment .

^ Costante, J. 1978. Insecticide guide for control of major pests
and cost comparison. Univ. of VT (mimeo) .

Based on 400 gal. /A dilute for IPM orchards

Table 3 gives a list of the major apple- infesting pests. This
list was based on an on-tree harvest survey of 2,000 fruits per
orchard (100 fruits per tree on each of 20 trees) . In both the IPM
and check orchards, TPB accounted for the greatest percentage of fruit
injury. (However, we found no good relation between TPB trap captures
and TPB injury levels at harvest.) In the IPM orchards, EAS ranked
second in terms of injury level. (We found that EAS trap captures
and EAS injury levels are highly related, and for this reason we will
be able to even more accurately time and predict need for insecticide
applications aimed against EAS next year.) In the check orchards,
San Jose' scale and green fruitworms caused more injury than EAS and
other pests except plum curculio. We attribute better control of GFW
in the IPM orchards to our careful monitoring of the presence of the
larvae. In the IPM orchards, we attribute the excellent control of
AMP with minimum insecticide usage to the information obtained from
AMF captures on the unbaited spheres. Captures of AMP on these
spheres were considerably greater and much better related with AMF
injury to fruit at harvest than were captures on the baited spheres
on Zoecon yellow rectangles. In one IPM orchard, no mature female
AMF were captured until August 14, and few CM were captured. Based
on our recommendations stemming from these trap captures, no insecti-
cide was applied between June 6 and August 16. The result: no fruit
injury whatsoever from AMF, CM, or any other fruit pest except early
season TPB. We found almost no codling moth and leafroller injury
on fruits at harvest in any of the other orchards.

.33%

(1)

.54%

(4)

.17%

(5)

.08%

(6)

96%

(2)

C8)

05%

(7)

59%

(3)

-15-

TABLE 3. Major Pest Species and Average Injury Levels^. Numbers

in Parentheses Indicate Relative Ranking o£ Injury Level

Pest IPM Orchards (8) Check Orchards (8)

Tarnished Plant Bug 1.60% (1)

European Apple Sawfly 0.68% (2)

Plum Curculio 0.17% (3)

Apple Maggot Fly 0.13% (4)

San Jose Scale 0.03% (5)

Codling Moth 0.01% (6)

Leafrollers 0.01% (7)

Green Fruitworm (8)

Other 0.01%

Based on on-tree surveys of 2,000 fruit per orchard (or orchard
block) at harvest (100 fruit on each of 20 trees) .

The mite results in our IPM orchards were also encouraging. Our
8 IPM orchards averaged 1.2 miticide applications as compared with an
average of 1.6 applications in the 8 check orchards, and at the same
time had slightly more predator mites (Table 4) . We attribute the
slightly increased number of predator mites to selective use of
pesticides in the IPM orchards. (We asked growers not to use chemi-
cals that had previously been shown to be toxic to mite predators
[ Fruit Notes 43(5)]). In Orchard A (Table 5), which had a high num-
ber of predator mites (both A^ fallacis and yellow mites) , no miticide
application was needed this year. In Orchard B, in which an herbicide
shown to be toxic to A. fallacis was used, 3 miticide applications
were needed. As the eTfects of selective use of pesticides non-toxic
to predator mites take hold in IPM orchards in future years, we expect
increasing predator buildup and gradually decreasing need for miticide
application.

TABLE 4. Summary of 1978 IPM and Check Orchard Mite Results

Orchards

European

Mites

Red

Two- Spotted
Mites

Predatory Mites
A. fallacis Yellow Mites

oil

No.

Treatments
Miticides

8 IPM
8 Check

2.1
2.4

5.3
0.7

0.07 0.01
0.05 0.01

0.8

1.2
1.6

■16-

TABLE 5. Mite Results in 2 IPM Orchards in 1978

IPM
Orchard

European Red Two-Spotted Predatory Mites

Mites Mites A. fallacis Yellow Mites

Avg. No. Treatments
Oil Miticides

0.2

0.03

0.06

0.07

11.4

0.08

0.01

* Sprayed under trees with Amnate in June.

Our plans for 1979 include increasing the number of IPM orchards
and the IPM acreage in each. (The number of check orchards to be
scouted will probably decrease.) Since we have better predictive
tools for monitoring HAS and AMF adults, our results next year should
be even better. The combined efforts of Dr. William Manning and Ted
Bardinelli of the Plant Pathology Department will also provide an
IPM approach to disease control.

In conclusion, our integrated insect pest management program in
1978 resulted in substantial overall savings of grower money and time,
through a reduced number of spray applications, and at the same time,
resulted in very high quality fruit production.

Cooperative Extension Service

University of Massachusetts

Amherst, Massachusetts

Ross S. Whaley

Director

Cooperative Agricultural Extension Work

Acts of May 8 and June 30, 1914

Official Business
Penalty for Private Use, $300.

POSTAGE AND FEES PAID
U.S. DEPARTMENT OF
AGRICULTURE
AGR 101

BULK THIRD CLASS MAIL PERMIT

FRUITpc
NOTES

PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES

COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.

EDITORS
W. J. LORD AND W. J. BRAMLAGE

Vol. 44 (No. 2)
MARCH/ APRIL 1979

TABLE OF CONTENTS

Monitoring Apple Maggot Flies. Sawflies, and

Plant Bugs with Visual Traps
Rootstock Testing on an International Basis
Treatment of Girdled Fruit Trees
Nutritional Problems in 1978 and Suggestions

for Fertilization of Apple Trees in 1979

Pomological Paragraph
Deeper planting may reduce suckering from
the rootstock on interstem trees.

Apple Disease Incidence in Massachusetts
in 1978

MONITORING APPLE MAGGOT FLIES,
SAWFLIES, AND PLAN