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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
1
3.5
7.9
3.4*
2.4
4.9
28.5
2
8.0
21.0
7.6
2.3
17.3
16.5
3
22.6
11.4
1.9
.0
8.7
27.7
4
15.5
11.7
1.5
6.2
17.0
12.5
5
23.7
11.3
.0
2.2
13.9
20.5
6
13.5
21.6
2.3
.9
7.4
24.8
7
18.1
14.6
1.0
.2
12.2
23.9
8
7.2
3.5
.0*
5.9
17.2
9.8
9
10.7
15.6
10.7
2.6
13.2
20.2
10
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
1
$ -651
11
$1,277
21
$1,477
2
-174
12
1,360
22
1,490
3
-175
13
1,433
23
1,469
4
-62
14
1,446
24
1,451
5
205
15
1,459
25
1,432
6
515
16
1,462
26
1,413
7
847
17
1,465
27
1,394
8
1,033
18
1,467
28
1,350
9
1,113
19
1,469
29
1,310
10
1,194
20
1,471
30
1,269
The present value formula with uneven income streams is as
follows:
PV = ^1 + ^2
TT^TT
(1 + i)
R
n
(Ui)
n
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)
30
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)
TU
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.
7
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
D
M.13
C-
Robusta 5
B
MM 104
B
M.2
B
M 106
A
M.7
A
MM 111
C-
Antonovka
B
AInarp 2
A
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
A
C-
C
B-
c
B
B
C
A-
C
c+
B+
A
B
B
C
A+
Medium
vigor range-
'60 to 85% c
)f standard
A
C
E
E
B
c-
B
B
6
C
B
c+
A
B
C-
C+
B
B-
B-
C
B-
c
a
C-
B +
B+
B
c
A
B
B+
A
A+
?
?
A
B+
A
?
Half -size .
?
and smaller
?
A
A+
D
A+
D
C
B
A+
C-
C-
C-
c
A
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
10
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
11
(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)
6x
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.
12
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
13
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.
14
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
Penalty for Private Use, S300
POSTAGE AND F EES PAID
U.S. DEPARTMENT OF
AGRICULTURE
AGR101
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. 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-
15
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.
16
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.
17
4
i
]
\
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.
18
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
7
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.
19
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.
20
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-
21
'■■ 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
22
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.
23
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.)
24
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
25
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.
26
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
27
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.
28
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
;d
Cgms)
6.
,6
5.
,6
7,
,4
5,
,5
5.
,0
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).
29
-»■*';
- —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.
30
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.
(c) Seconds to deliver 1 gat. /Trees per gal. =
63/9 = 7 seconds/tree.
(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
31
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.
32
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 -
I
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.
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.
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
I
i
I
4
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.
10
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)
5
38
5
3
38
5
3
38
2
3
32
2
3
32
2
3
32
2
3
32
2
3
32
2
3
32
2
3
32
2
3
32
2
3
32
*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
c
rown t
(°F)
emp
27
27
24
3
20
5
25
22
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
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
8
86
6
72
4
6
8
34
14
6
6
8
4
5
"2T
14
38
21
29
57
27
2
2
6
18
18
6
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.
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.
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
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NOTES
PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES
COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS. UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.
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
I
VARIETIES OF PEACHES FOR MASSACHUSETTS
J.F. Anderson
Department of Plant and Soil Sciences
Variety
Recommended
Flesh
App
roximate
for
color
harvest date*
C
§
H
W
-42
T
Y
-41
T
Y
-41
C
a
H
Y
-40
T
Y
-38
C
§
H
Y
-32
H
Y
-32
C
5
H
W
-30
C
^
H
Y
-28
T
Y
-25
T
Y
-25
C
^
H
Y
-23
C
Y
-18
C
5
H
Y
-16
T
Y
-12
C
5
H
Y
- 7
C
Y
T
Y
+ 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
I
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
Very early
Early
Midseason
Midseason
Late
Late Sept.
Late
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)
(C) + CD) = (F)
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
11
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°^
0%
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
39
Red
34
Black
31
Orange
27
White
131
Clear Plexiglas
129
Yellow
109
Gray
96
Green
71
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.
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 procedure plus limb positioning
(spreading) is needed on vigorous young Delicious trees to encourage
bloom and fruit set.
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.
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. Some growers apply the K fertilizer
in the fall and the N fertilizer in the spring.
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.
e.
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
12
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
14
/
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
15
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:
16
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
C
Average
Alternate
middle
A
B
C
Average
1.3
5.0
5.7
4.0
1.0
13.0
9.3
7.8
56
110
44
120
127
205
76
145
51
185
76
111
75
157
67
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:
A
B
C
Avg.
A
B
C
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
0.1
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
2
.70
3
,60
108
.80
17
.50
1
.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.
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.
15-
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William J. Lord
Extension Pomologist
University of Massachusetts
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Amherst, MA 01003
Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whaley
Director
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Acts of May 8 and June 30, 1914
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NOTES
PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES
COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.
EDITORS
W. J. LORD AND W. J. BRAMLAGE
Vol. 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
83
72
70
No, of bruises
per apple
Sq . cm . of
bruised area
per apple
Deep-cell fiber
trays
62
1.7
1.6
1.4
1.1
210
169
102
77
Dry fiber trays-- +
paper wraps on all
apples, OR
69
2 pads in bottom
of carton, OR
72
filled paper pad
on each layer, OR
59
Urethane sheet on
each layer
57
ing 20"C apples
71
1.2
1.2
0.8
0.9
1.3
100
98
41
93
A************ ft**
8-
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.
9-
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.
****************
11
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
87
High
3.0
oz
100
High
1.0
lb
100
High
1.0
lb
70
High
4.0
oz
46
Moderate
1.0
oz
32
Moderate
1.0
lb
19
Low
2.0
lbs
15
Low
1.5
lbs
10
Low
10.0
oz
10
Low
3.0
lbs
3
Low
hydrochloride) 92SP
8.0
oz
85
High
Kelthane (dicofol)
35WP
1.3
lbs
56
Moderate
*Plictran (cyhexatin) 50 WP
6 .0
oz
33
Moderate
Omite (propargite)
30WP
1.5
lbs
9
Low
Vendex 50WP
0.5
lb
8
Low
FUNGICIDES
Glyodex WP
0,5
lb
28
Low
**Glyodin 30%EC
1.5
pts
21
Low
Dikar WP
1.5
lbs
15
Low
Benlate (benomyl) :
5 WP
6 .0
oz
15
Low
Thiram (thylate) 65WP
1.0
lb
12
Low
TABLE 1. (Continued)
16
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
14
High
High
Low
Moderate
Low
Low
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.
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.
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
86
Hexane
4.1
3.9
16
24
118
80
Water
7.4
5.9
27
44
64
52
Methanol
8.2
3.3
28
31
34
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.
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.
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
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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
I
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
H
a H
5 H
^ H
T
C
H = Home garden
Very early
Early
Early
Early
Early
Early-midseason
Midseason
Midseason
Midseason
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.
3-
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
y
Average Number/Trap
EAS
X
AMP
,w
CM
,v
RBLR
u
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
X
w
u
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) .
X
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.
2
.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
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
B*
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 PLANT BUGS WITH VISUAL TRAPS
Ronald J. Prokopy
Department of Entomology
Introduction
With the advent o£ integrated pest management programs in
commercial apple orchards inMassachusetts and other apple-growing
regions of the United States, there is increased emphasis on the
ability of growers, orchard scouts, and extension agents to accur-
ately monitor population levels of injurious apple insects and
mites .
Certain pests, such as aphids, spider mites, leafhoppers,
leafminers, and scale insects attack principally or exclusively
the vegetative parts of the tree and can be tolerated in small
or even moderate numbers without economic injury. Their popu-
lation levels can be monitored with reasonable accuracy by direct
visual examination of foliage or branches.
Other pests, such as green fruitworms and oblique-banded,
red-banded, and fruit-tree leafrollers feed, as larvae, from
the exterior of the fruit. While even a few larvae may cause
economic injury, larval populations and the readily discernible
injuries they cause, can be rather accurately monitored by direct
visual examination of fruit.
Still other pests, such as tarnished plant bug, European
apple sawfly, plum curculio, apple maggot, and codling moth,
feed as adults or larvae on developing buds or fruit. They
can not be tolerated in appreciable or even small numbers with-
out economic injury. Except for plum curculio, their feeding
and egglaying activities are rather difficult and tedious to
accurately detect by direct observation. Populations of these
pests are best monitored in the adult stage. The monitoring
method must be sensitive, so that detection of very low popu-
lation densities is possible, and pesticide application, if nec-
essary, can be made before the occurrence of economically un-
acceptable feeding injury or egglaying.
In the 8 commercial apple orchards in our 1978 integrated
pest management (IPM) program in Massachusetts, it was the lat-
ter 5 pests which accounted for nearly all of the insect injury
on the 16,000 apples examined at harvest: 1.601 by plant bug,
0.68°^ by sawfly, 0.17% by plum curculio, 0.131 by apple maggot,
and 0.01% by codling moth, with all remaining insect injury to
the fruit totalling 0.051 (see Fruit Notes 44(1) for further in-
information on the 1978 results of the apple IPM program in Massa-
chusetts). This same sort of insect injury pattern is probably
characteristic of several other eastern states as well.
During the past few years, we have been attempting to develop
effective trapping devices for accurately monitoring adult popu-
lation levels of plant bug, sawfly, apple maggot, and plum curcu-
lio.
Most entomologists who have sought to develop insect traps
have been primarily interested in uncovering highly stimulating
odors, such as sex pheromones, which can attract an insect from
a considerable distance. In recent years, this approach has met
with outstanding success. Witness the development of sex phero-
mone traps for male codling moths, leafrollers, fruitworms, and
leafminers by Dr. Wendell Roelofs and colleagues at the New York
State Agricultural Experiment Station at Geneva.
In many instances, however, sex pheromone traps are so power-
ful that they attract individuals from distances well beyond the
borders of the orchard. Hence, it has often proven rather diff-
icult to accurately relate pheromone trap captures in an orchard
to the number of pest adults actually present within the orchard.
Our approach has been an attempt to uncover attractive visual
stimuli. Such stimuli, when incorporated into a trap, would lure
insects only from a distance of a few yards or less. Theoretically,
therefore, visual traps would have the advantage of providing
estimates of only those pest adult numbers actually present with-
in the orchard.
Thus far, this approach has yielded 2 sorts of effective
visual traps for apple maggot flies, one for European sawfly,
and one for tarnished plant bug. Some of the research that led
to the development of these visual traps has been outlined in
recent issues of Fruit Notes: 41(5), 41(6), 43(1), and 43(2).
In this article, I tie together elements of our previously
described findings and present new findings on the relationship
of levels of trap captures to levels of injury caused by each
pest.
Specific Ingredients of Our Approach
(^x^^^ -juxL^.v-i-mj.'w.j. iii-j~i.\^y rv \^ o.uu'^iiiUL- \,\J iii-LiiiJ-\_ („ii\_,o\_- vj.oiacj-j. j.v_-a.-i-v--\^i
ance patterns with pigments or paints having the same type of re
flectance pattern. Fourth, we apply these pigments or paints to
objects whose shape and size is similar to that of the correspond-
ing tree structures. Finally, the objects are coated with a clear
sticky substance (such as Tangletrap*) which captures alighting
insects, and are hung in apple trees to assess the responses of
the adults.
n
Trade Name
-3-
Apple Maggot Flies
Apple maggot flies, prior to reaching sexual maturity, make
frequent visits to apple tree leaves, where they feed on insect
honeydew and other surface substances, and rest. After reaching
sexual maturity, they make frequent visits to the fruit, where
they mate and lay eggs. Visits to the twigs and branches are
infrequent.
A green rectangle of medium size (6x9 inches) roughly
mimics the hue reflectance pattern and form of clusters of apple
foliage. While apple maggot flies will alight on such a green
rectangle, they alight in much greater numbers on yellow rect-
angles, which have the same sort of hue reflectance pattern as
apple leaves, but reflect light at a much higher intensity than
leaves. It seems as though the flies perceive yellow rectangles
as being super-bright or super-normal clusters of foliage. Day-
light fluorescent yellow is an especially bright and attractive
hue .
When baited with an odoriferous substance such as an ammon-
ium acetate-protein hydrolysate combination (which apparently
mimics the smell of insect honeydew), and coated with Tangletrap,
daylight fluorescent yellow rectangles are excellent for monitor-
ing populations of food-seeking flies.
A yellow or green 2-inch diameter sphere closely mimics the
hue reflectance pattern, form, and size of a developing apple.
While mature apple maggot flies readily alight on such spheres,
they alight in considerably greater numbers on red, violet, and
black spheres 3-5 inches in diameter. It seems as though these
dark colored spheres, on the basis of greater contrast against
the background, are more readily detectable by the flies than
are the light colored ones -- much the same as humans can more
easily locate red apples than yellow or green apples in a tree.
Apparently the flies view large spheres as being super-large or
super-normal apples. Our studies have shown, however, that if
a sphere is overly large--for example, 12 inches diameter--it
is less likely to be viewed as an apple and in fact attracts
fewer flies than a 3 1/2-inch sphere.
When coated with Tangletrap, 3 1/2-inch diameter red spheres
provide excellent traps for monitoring populations of apple maggot
flies seeking mating and egglaying sites.
In 1978, we compared 6x9 inch odor-baited yellow rectangles
(sold commercially as Pherocon AM Standard Traps by Zoecon Corp.,
Palo Alto, California) with 3 1/2-inch diameter dark red spheres
coated with Tangletrap in 16 commercial and 4 abandoned Massa-
chusetts apple orchards. Although early-season maggot fly cap-
tures in the abandoned orchards were slightly greater on the yel-
low rectangles than on the spheres, captures in the commercial
orchards were consistently earlier and consistently greater in
weekly and total numbers on the spheres than on the rectangles.
-4-
In commercial orchards, the great majority of apple maggot flies
are immigrants, and apparently are more in search of mating and
egglaying sites than in search of food. Hence, the greater effect-
iveness of the spheres for monitoring apple maggot flies in comm-
ercial orchards.
European Apple Sawflies
European apple sawfly adults make frequent visits to apple
blossoms, where they feed on the pollen and lay eggs in the recep-
tacles. Some mating and resting also occurs on the blossoms. They
make comparatively few visits to the leaves and branches.
Certain white paints which reflect little or no light in the
ultraviolet part of the spectrum closely mimic the hue reflect-
ance pattern of apple petals, although they reflect at a higher
intensity, than tlic petals. Medium size rectangles (6 x 8- inches)
coated with such paint plus Tangletrap attract and capture large
numbers of sawfly adults. Evidently, the sawflies perceive the
white rectangles as being super-bright or super-normal clusters
of apple blossoms. However, not just any white surface will
attract sawflies. For example, white paper, white cardboard, and
lead white paints reflect considerable amounts of ultraviolet
light, which, although not visible to humans is readily visible
and in fact quite repulsive to sawflies. Fortunately, the white
rectangles attract and capture few honeybees.
Tarnished Plant Bugs
Tarnished plant bug adults make frequent visits to apple
buds and blossoms, where they feed. Less frequently, they visit
leaves and branches, where they rest. Mating and egglaying seem
to be rather infrequent on apple trees, principally occurring on
ground cover vegetation.
Just as they mimic the hue reflectance pattern of apple
blossom petals, certain non-ultraviolet-reflecting white paints
also approximate the hue reflectance pattern of developing apple
buds. As with sawflies, 6 x 8-inch rectangles coated with such
paints plus Tangletrap capture considerable numbers of plant bug
adults. However, our research indicates that plant bug adults are
substantially less visually specific in orientation to the hue or
form of apple tree structures than are apple maggot flies and
sawflies. Hence, visual traps may ultimately prove of somewhat
more limited value for precise monitoring of plant bug populations
Where to Purchase Visual Traps
These visual traps for apple maggot flies, sawflies, and
plant bugs can be purchased at modest cost from New England Insect
Traps, Leyden RFD, Bernardston, MA 01337 ($1.25 per 3 1/2-inch
red wooden sphere with accompanying Tangletrap; $1.00 per non-
ultraviolet white cardboard rectangle, pre-coated with Tangletrap)
-5-
How to Position Visual Traps in Trees
Proper use o£ visual traps demands more careful attention
to trap placement than is the case with sex pheromone traps.
The visual traps, best hung from branches on the south side of ap-
ple trees at heights of 20-40 inches for plant bugs and 6-8
feet for sawflies and maggot flies, must be readily visible to
insects approaching from any direction. It is advisable, there-
fore, to remove all foliage and fruit within 12 inches or so of
the sides, top, and bottom of a trap. Beyond this distance,
however, there should be as many buds, blossoms, leaves, or
fruits as possible to attract insects into the general area.
Presently, we are using one visual trap of each type per 2 acres
of trees in our pest management orchards.
Relation Between Trap Captures and Insect Injury Levels
The ultimate proof of the usefulness of such visual traps
lies, of course, in the accuracy with which trap captures esti-
mate numbers of injury-causing adults actually present in the
orchard. In 1978, we therefore made an attempt to establish
indices relating levels of trap capture to levels of injury
caused by each pest. We hung 6-10 traps of each type in each
of 16 commercial orchards.
The results showed the following correlation values of trap
captures with injury levels (+ 1.00 would be a perfect positive
correlation, indicating a perfect relationship of trap captures
to injury levels): (a) apple maggot captures on red spheres with
apple maggot egg-laying stings, + 0.87 (b) sawfly captures on
non-ultraviolet reflecting white rectangles with sawfly injury
scars on mature fruit, + 0.82; and (c) plant bug captures on non-
ultraviolet reflecting white rectangles with abscission of devel-
oping buds caused by plant bug feeding, + 0.67.
These high positive correlation values are very encouraging
and suggest that prospects are good for establishing reliable
indices relating visual trap captures to insect injury levels,
and therefore for using visual trap captures as a basis for de-
ciding if or when pesticide treatments against plant bugs, saw-
flies, and apple maggot flies are economically merited in a given
block of trees. We hope that our studies during the next 2-3
years will refine and validate the initial indices obtained in
1978. Until then, the principal value of the visual traps will
be in detection of the first appearance and the disappearance of
these pest adults in orchards.
-6-
ROOTSTOCK TESTING ON AN INTERNATIONAL BASIS
William J. Lord
Department of Plant and Soil Sciences
In the past, rootstock studies were uncoordinated efforts and
results have varied from state to state with little chance of iso-
lating the influences due to climate and soil differences. In 1976
the North Central Regional Cooperative Project NC-140 entitled
"Scion/Rootstock and Interstem Effects on Apple Tree Growth and
Fruiting" was initiated with the following objectives.
Objectives :
1. To evaluate the production efficiency of available and
potentially useful rootstocks or interstems for fruit
trees which are potentially precocious, dwarfing, free
standing, easy to propagate and adapted over a wide range
of climatic conditions in the North Central Region.
2. To determine the propagation practicability of new root-
stocks and interstem material and ascertain the anatomical
and physiological factors in graft unions that determine
compatibility.
3. To ascertain the cause and prevention of the decline of
new and existing rootstocks and interstems and evaluate
the influence of various cultural practices on rootstock
survival and performance.
Under Objective 1, a uniform interstem planting was establish-
ed in 1976 in Illinois, Indiana, Iowa, Kansas, Massachusetts, Mich-
igan, Missouri, Ohio, and Wisconsin, and a partial planting was
established in Kentucky. 'Millerspur Delicious' and ' Empire ', with
8-inch interstem of M.9 on either Antonovka, MM. Ill or Ottawa 11
rootstock, are being evaluated.
Currently, NC-140 is being expanded so that a 1980 rootstock
planting will be established by at least 20 cooperators in U.S.A.
and Canada. At each location a planting of 'Redchief Delicious'
(spur- type) on M.9, Ottawa 3, EMLA27, EMLA9 , EMLA7 , EMLA26, MAC9,
MAC24, and OARl will be established. (The EMLA's are virus-free
clones of M.9, M.7, etc., the MAC's are Michigan State apple clones,
and the OARl is a clone introduced by Oregon State Agricultural
Experiment Station.)
Other Cooperative Rootstock Plantings will be established
later in the 1980's. Hopefully, our NC-140 project will prove to
be a benefit to growers and apple tree nurserymen, since coordinated
research should lead to clearer information about apple rootstock
performance .
************
-7-
TREATMENT OF GIRDLED FRUIT TREES
William J. Lord
Department of Plant and Soil Sciences
Girdling or partial girdling of fruit trees occurs annually
in spite of orchard sanitation, poison baits and mechanical pro-
tectors, and may be particularly severe in years of heavy, persist-
ing snowfall, as occurred during the winter of 1977-78. You can
help prevent damage when snow accululates above the wire or plastic
guards by tramping the snow to lower its height.
Determining the Treatment
1. Trees not worth saving should be removed and replaced.
2. If apple, pear or plum trees with injury above the graft
union are only 1- or 2-years old, they can be cut below
the girdled area. Shoots will then develop from the re-
maining stub. One of these can be selected during the
following spring for a new tree. B£ sure the selected
shoot originates above the graft union. In case of inter-
stem trees the shoot must originate above the interstock.
3. If apple or pear trees are 1-1/2 or 2 inches in diameter
they can be cleft grafted. Cleft grafting is less likely
to be successful on stone fruits.
4. Trunks of girdled apple, pear or plum trees more than
2 inches in diameter can be bridge grafted. Peach trees
usually do not respond satisfactorily to bridge grafting.
5. When the roots of an apple tree are so badly injured that
scions cannot be readily attached to them, inarching can
be done.
6. Repair of girdled apple trees is complicated by planting of
interstem trees. Girdling of the interstem portion, usually
M.9 (it is reported that mice prefer M.9), means that when
bridge grafting, cleft grafting or inarching is done part,
if not all, of the dwarfing influence of the interstem will
be lost. A solution to this problem is using scion wood
and rootstocks from a stool bed of M.9 maintained on the
farm.
Season for Repair Grafting
Repair grafting by bridging or inarching should be performed
when the bark is slipping readily. Under Massachusetts growing
conditions, the bark may not begin to slip readily until mid-April.
Cleft grafting can be done earlier (March) since it is not necessary
for the bark to slip. However, when the scions for bridge and
cleft grafting or the nursery tree for inarching are kept dormant
in storage, grafting can be successfully done even though the
trees have made considerable growth.
Selection of Scion Wood for Bridge Grafting
It usually is necessary to obtain scions in advance of their
use in order to have them dormant. Water sprouts or well-ripened
one-year terminal growth make good scions for bridge grafting.
Scions can vary in size from that of a lead pencil to one-half
inch in diameter, the largest scions being used on larger wounds.
Scions may be taken from the same tree or any other available
compatible sort, but preferably from a winter hardy variety such
as Cortland or Mcintosh apple.
Trees for Inarching
Use dormant nursery trees 3 to 6 feet in height.
Mechanics of Repair Grafting
Farmers' Bulletin Number 1369 of the U.S. Department of
Agriculture gives detailed instructions for bridge grafting and
inarching. A limited supply of this publication is available at
your County Extension Service. Also available from your County
Extension Service is our publication on cleft grafting.
Grafting Compound
For the protection of grafting wounds, many growers now use
asphalt emulsion instead of a grafting wax. It can be obtained
from most distributors of farm and gardening supplies. Asphalt
emulsion should be applied on the tip ends of the scions and the
cut stub of the trunk when cleft grafting, and over the area where
the scions or top of the inarched tree meets the stock of the
girdled tree. Applying the emulsion on the injured section of the
trunk is also advisable to prevent weathering.
The Number of Scions
The following are about the right number of scions for dif-
ferent sized trees:
(1) Tree 2 inches in diameter, 3 scions
(2) Tree 3 inches in diameter, 4 scions
(3) Tree 6 inches in diameter, 6 scions
(4) Tree 10 inches in diameter, 8 or 10 scions.
On partially girdled trees use a proportionate number of
scions. A tree one-quarter or more girdled should be bridge grafted,
-9-
Care of Scions After Grafting
Inspect repaired trees periodically after grafting and recoat
with grafting compound any areas where cracking has occurred.
This phase in the process of bridge grafting and inarching is most
apt to be neglected. Thus, the following procedure should increase
the reliability of coverage. Place masking tape over the graft-
ing compound- coated areas (where the scions or top of the inarch
tree meet the stock of the girdled tree). Then, coat the masking
tape with grafting compound.
The scions used for bridge grafting and the trees used for
inarching must be kept from producing shoots. As buds on the scions
swell, rub them off. When inarching, let 1 bud develop into a
shoot, preferably the bud nearest to the graft. When you are sure
the graft has "taken", it should be removed.
General Considerations
1. As soon as the injury is discovered, it may be possible to
save some of the cambium layer cells (where new cells are pro-
duced in the trunk) by promptly applying the asphalt emulsion
or grafting wax to the injured area.
2. Occasionally suckers are present or arise later from the area
below the wounds. Suckers that extend above the wounded surface
may be used as "inlay scions" at the top end.
3. Trees leaf out and often fruit the first season after the bark
and cambium layer are destroyed around the tree trunk. How-
ever, the vigor of these completely girdled trees varies con-
siderably. On some trees the foliage and fruit appear normal,
on others, foliage may be light in color but fruit size normal,
and on some other girdled trees, the foliage may be light in
color and sparse, and the fruit small.
The reason why completely girdled trees leaf out and often
fruit the first season after the bark and cambium layer are des-
troyed around the tree trunk is because water and other materials
which are taken up by the roots from the soil pass up to the leaves
through the wood. In the leaves the water and the carbon dioxide
taken from the air by the leaves are united chemically, through the
action of sunlight, into sugar. After the manufacture of the plant
foods by the leaves, they move to other parts of the tree through
the phloem which is found in the bark. When the phloem has been
destroyed by girdling, this food cannot move to the roots. Roots
will continue to grow and take up water and minerals only as long
as their food supply holds out, and the above-ground portion will
continue to grow only as long as it continues to receive water and
minerals from the roots. Reserve food stored in the roots enable
the roots to function for some time, often a year or 2, thus keep-
ing the top of the tree alive. However , a completely girdled tree ,
unless repaired , will eventually die Trom starvation of the roots .
-10-
NUTRITIONAL PROBLEMS IN 1978 AND SUGGESTIONS
FOR FERTILIZATION OF APPLE TREES IN 1979
William J. Lord and Mack Drake
Department o£ Plant and Soil Sciences
Prospects for a heavy bloom in 1979 are not too likely follow-
ing the large crop in 1978, However, there are ample flower buds
for a good crop in 1979 if weather is favorable at bloom.
The analysis of leaf samples from commercial orchards showed
that potassium (K) and manganese (Mn) were deficient in some orchards
in 1978, and boron (B) was generally low. Foliar calcium (Ca) levels
were considerably higher than most years; nevertheless, bitter pit
on Cortland was very prevalent in some orchards and we were surprised
to find a serious amount of cork spot in some Red Delicious fruit,
and Empire. With the above observations in mind, we present the
following suggestions as a guide for fertilization in 1979,
Nitrogen (N) : Most orchards had a large crop in 1979, there,
fore, the trees may be low in available N for utilization this
spring. We suggest higher rates than normal of N this year unless
the trees were excessively vigorous in 1978 or were heavily pruned
this past winter.
Potassium (K) : K was low in many orchards and even deficient
in some in 1978, probably due to the demand for this element by
the large crop, or because the dry weather reduced its availability.
The leaf scorch symptoms of K deficiency may be confused with
the leaf margin burn from calcium chloride sprays. However, unlike
leaf burn from calcium chloride sprays, the scorch of leaf margins
due to K deficiency progresses from the older leaves to the younger
leaves of current season shoots as the season advances. The scorch
may turn gray in color and leaf fall may occur late in the growing
season.
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 1978.
The requirements of apple trees for K (expressed as K-,0) , based
on potential yields, are as follows: (a) less than 15 bu. 1.3 lbs,/
tree; (b) 15 to 25 bu: 1,3 to 2,7 lbs, /tree; and (c) more than
25 bu: 2,7 to 4,3 lbs, /tree. It is necessary, however, to maintain
a balance among the essential nutrients for apple trees. For example,
excessive levels of K can reduce both leaf and fruit Ca, Therefore ,
we strongly urge that you participate in our leaf analysis program to
more accurately determine the K needs of your apple trees .
-11-
Calcium (Ca) : The use o£ calcium chloride (CaCl2) sprays to
increase the flesh Ca content o£ our apples is rapidly becoming a
standard practice in commercial orchards. Our suggestions for their
use in 1979 are as follow:
Apply foliar sprays of CaCl2 starting about 3 weeks after petal
fall and repeat at 2-week intervals, totalling 6 or 8 applications.
Apply 6 to 8 pounds CaCl^/acre/spray until mid-July. After mid-July,
apply 10 pounds/acre/spray. Use a technical grade CaCl2 such as Allied
Chemical Flakes, 77-801 CaCl^- Other brands may be equally suitable.
Experience in Massachusetts has shown that CaCl2 can be combined
with pesticide sprays. However, there is limited evidence that the
combination of Guthion (azinphosmethyl) 50 WP and CaCl^ may increase
foliar burn. Do not mix CaCl- and Solubor sprays. Always dissolve
the CaCl^ in a~p^ail of water and add this last and when the spray tank
is nearly full.
Foliar CaCl^ sprays may be applied dilute (300 gallons/acre) or
up to 6x concentration (50 gallons/acre). In our tests, flesh calcium
has been increased more by 6x concentration than by dilute. In 1977
the effectiveness of foliar CaCl^ sprays at 6x and lOx was compared on
Mcintosh. The concentrations were equally effective for increasing
flesh calcium, and foliar burn was not excessive.
CaCl^ sprays can cause burn of leaf margins. Foliar injury usu-
ally is more serious on Mcintosh than on Delicious. If foliar injury
occurs, do not apply again until 1 inch of rain falls. Foliar burn
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 that CaCl, injury varies with season
because of such factors as rainfall and temperature.
Boron (B) : B can be supplied to apple trees either by foliar or
soil applications . Use the most economical and convenient method. How -
ever , it is safest to apply all elements as a fertilizer except in
emergency situations .
Soil applications of boron should be applied to orchards every
3 years. The rate of application per tree vary with tree age and size.
In low density orchards, apply 1/4 pound of borax (11.11 actual B) or
its equivalent under young trees coming into beari ng, 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 211 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 following
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 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 .
-12-
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
elementT 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) : Apple leaves from trees showing Mn deficiency
in 1978 had 12 to 15 ppm of this element which is much below the
desired levels of 30 to 60 ppm. Mn deficiency symptoms are charact-
erized by interveinal fading of chlorophyll with the veins remaining
green. For those who are unfamilar with the symptoms of Mn deficien-
cy, we refer you to the photograph that appeared in the May-June
1978 issue of Fruit Notes .
Mn deficiency should be corrected on trees showing considerable
foliage damage. Although we have no definite proof, Mn deficiency
appeared to be associated with excessive fruit drop on a few trees
in one orchard in 1977. Mn deficiency can be corrected by foliar
applications of manganese sulfate or of a fungicide containing Mn.
Apply manganese sulfate at about first cover at the rate of 3 lbs.
per 100 gallons of water. If using a Mn-containing fungicide, 2
or 3 applications are necessary with timings about petal fall, first
and second cover.
Zinc (Zn ) : Based on optimum levels of Zn established by Maine,
some of our orchards continue to be low in this element. Dr.
Warren Stiles, University of Maine suggests a dilute spray of Zn
chelate (EDTA) at the rate of 1 to 2 lbs. per 100 gallons of water
at tight cluster or first cover in orchards low in this element.
He considers 25 to 50 ppm to be the optimum range for zinc in
apple tree foliage.
AAA**************
POMOLOGICAL PARAGRAPH
Deeper planting may reduce suckering from the rootstock on inter -
stem trees . Dr. James Cummins, New York State Agricultural Experi-
ment Station, Geneva, N.Y. is examining the interaction of interstem
length and planting depth. The interstems vary from 10 to 25 cm
(1 inch = 2.54 cm) in length and planting depths vary from 1 cm of
the interstem being exposed above ground, to the entire interstem
-13-
being exposed. The most s
that the numbers of rootst
increasing length of inter
had little effect on numbe
suckers are troublesome in
ing the trees with only th
above ground may reduce su
to prevent scion rooting,
inches of interstem are st
soil or gravel around the
it is to lift the tree if
around a tree planted too
water to collect near the
ignif icant
ock sucker
stem expos
rs of suck
some plan
e top 4 in
ckering an
Even if t
ill above
trunk if t
it is too
deep resul
trunk. ]
ft*********
results after 3 years are
s increased directly with
ure, while length of interstem
ers. [Editor's Note - Root
tings of interstems. Plant-
ches of the interstem being
d should be a sufficient height
he tree settles 2 inches, 2 more
ground. It is easier to add
he interstem is too high than
low. Removal of soil from
ts in "dishing" which allows
APPLE DISEASE INCIDENCE IN MASSACHUSETTS IN 1978
Ted R.
Bardinelli,-' Daniel R. Cooley,-'
and William J. Manning-
Department of Plant Pathology
The apple plant pathology program in 1978 focused on disease
surveys. Orchards in all parts of the state were evaluated peri-
odically for disease incidence. The twenty orchards in the IPM
program were the most intensively surveyed, particularly at harvest
Accumulated survey data will allow us to begin to determine the
incidence and relative importance of the various apple diseases
and will also allow us to examine new problems and re-examine
existing ones.
The statewide disease survey showed the current status of dis-
eases to be as follows:
1) Apple Scab
Apple s
1978. Wher
back to rea
problems wi
at critical
growers exp
developed i
and found t
To our know
chusetts .
cab was not
e scab was
sons such a
th spray di
times, and
ressed cone
n their ore
hat fungici
ledge, ther
a serious problem in most orchards in
a problem, it was possible to trace
s problems with sprayer calibration,
stribution, failure to apply fungicides
other grower management problems. Some
ern that fungicide-resistant scab had
hards. We investigated these situations
de-resistant scab was not the problem,
e is no fungicide-resistant scab in Massa-
y Extension Technicians, and y Associate Professor, Department
Pathology, University of Massachusetts, Amherst, 01003.
-14-
2) Quince Rust :
Quince rust was unusually prevalent on Red Delicious fruits.
We feel that this is due to late application of the first rust
spray. The first application should be made when the pink stage
is just beginning. Use of a broad- spectrum fungicide for both
scab and rust might be a good idea in problem orchards.
3) Frog Eye Leaf Spot :
Frog eye leaf spot (foliar stage of black rot) was unusually
prevalent on early-season leaves, especially on Cortland. Be-
cause of extensive early infections, most of these leaves fell
off and little fruit or later leaf injury was noted.
4) Black Rot:
Black rot was not severe on fruit. In older, poorly pruned
orchards, however, many major tree limbs were heavily cankered
or killed back by the black rot fungus. A "Yellow Bark" syndrome
was noted on the trunks of some apparently healthy trees in
several parts of the state. The black rot fungus was isolated
from "Yellow Bark" areas. We are currently investigating the
relationship of the black rot fungus to "Yellow Bark" and the
significance of "Yellow Bark" to tree health and vigor.
Poor Apple Growth Disease (PAGD) :
We investigated six cases of PAGD in 1978. The problem with
newly-planted trees either on old or new orchard sites that grow
poorly and unevenly and when severely affected they may die. The
cause of PAGD is unknown and we are examining possible causes under
controlled conditions.
Cedar Apple Rust and Powdery Mildew :
Neither of these diseases was a problem this past season.
Fire Blight :
Scattered pockets of fire blight were noted, principally in
Western Massachusetts. Mutsu and the Wayne were particularly sus-
ceptible.
Summer Fruit Problems :
Low level incidence of black rot, bitter rot, fly speck, and
white rot were noted late in the season and at harvest.
The IPM survey involved 20 orchards in central and western
Massachusetts. These were surveyed routinely throughout the season.
Results for the full-season survey are given on the next page.
-15-
Table 1 .Occur reiicc percent of disease incidence in random samples of
apple foliage and fruits as calculated during early, mid and late grow-
ing season.
Foliage
Apple scab
Frog eye leaf spot
Cedar apple rust
Powdery mildew
Alternaria leaf spot
Apple scab
Black rot
Early
Mid
Late
1.2
3.3
0.7
<0.1
0.2
4.5
1.4
<0.1
0.1
<.0.1
4.0
1.3
< 0.1
<0.1
<0.1
Totals
5.4
Fruit
6.1
5.3
1.0
0.0
3.2
<0.1
2.8
0.4
Totals
1.0
3.3
3.2
Apple scab and frog eye leaf spot were the major foliar diseases
Apple scab was the principal fruit disease.
A final fruit survey of 50,000 fruits was also performed just
prior to harvest. The results given below show the total disease
incidence of the fruits to be 2.81. Apple scab again proved to be
the most important disease affecting 2.3% of the fruits. Other fun-
gal diseases such as black rot, bitter rot, white rot, and fly speck
accounted for 0.223%. Calcium deficiencies were responsible for the
remaining 0. 312% .
Table 2. Average percent of fruits infected by disease at harvest.
Disease Causal organism % Incidence
Apple scab Venturia inaequalis 2.3
Black rot Physalospora obtusa 0.2
Bitter rot Glomerella cingulata 0.1
Wh i t e rot Botryosphaeria ribis . 1
Fly speck Microthyriell"a rubi 0.1
Cork spot Calcium deficiency 0. 3
Total fruit disease incidence 2.8
We will be continuing our surveys in 1979. Fruit growers that
have disease problems that they would like to have surveyed or
diagnosed, should contact Dr. William J. Manning in the Department
of Plant Pathology or their Regional Extension Agent.
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
(AGR 101)
BULK THIRD CLASS MAIL PERMIT
FRUITp^
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. 3)
MAY/JUNE 1979
TABLE OF CONTENTS
Influence of Training on Growth of Newly-planted
Trees
Promalin Studies in 1978 and Comments on Trial
Use in 1979
Harvesting Early Ripening Apple Cultivars
Chemical Thinning of Apples in 1979
Growth Regulator Spray for Growth Suppression on
Apple Trees
Suggestions on Use of Chemical Thinners on
Several Apple Varieties (chart)
Alternate vs. Every Middle Spraying for Apple
Pests in 1978
INFLUENCE OF TRAINING ON GROWTH OF NEWLY- PLANTED APPLE TREES
William J. Lord
Department of Plant and Soil Sciences
Recommendations for training 1-year-old whips the year of
planting have always varied. A pruning bulletin published by
the University of Massachusetts in the 1950 's, when trees on
seedling roots were being heavily planted, suggested that trees
planted early in the spring on good soil required no heading.
Other publications suggested that trees should be shortened to a
height of 30 inches at planting to cause branch development down
to within 18 inches of the ground. At least one publication
stated that heading height at planting was relatively unimportant,
the important thing being that trees grow well during the first
growing season.
The more current pruning publications, which include sugges-
tions for training trees on the more vigorous of the size-control-
ling rootstocks, frequently suggest heading heights of 24 to 30
inches and removal of growth closer than within 18 to 20 inches
to the ground. It is now common to find growers heading trees at
24 to 30 inches at planting regardless of variety or whether it
is a spur or non-spur type tree. Therefore, we became interested
in the influence of training on growth of newly-planted apple trees
Heading Height
Our studies show (Table 1) that shorter trees produce fewer
lateral shoots and spurs but shoot length may be longer in some
instances .
Table 1. Effects of Heading Height on Growth of Newly-Planted
Apple Trees, 1977.
Length No. of laterals : Avg. length Total
Heading of Spurs of
height leader and Shoots shoots Growth
shoots
(in.) (in.) (in.) (in.)
Marshall McIntosh/M7A
51a
57a
34a
39a
39 lib 10a 6a 7b 44a
36 12ab 9a 5a 7b 48a
30 14a 7b 3a 9a 54a
Lateral growth more than 2 inches in length.
^Values not followed by a common letter are significantly different
at the S% level.
36
ISb^
10a 5b 7a
30
17a
7b 6a 8a
Redspur Delicious/M7A
36
11a
7a 3a 7b
30
13a
4b 3a 9a
Redspur Delicious/MMlll
-2-
Heading height did not influence the number of lateral shoots
or the total growth (Table 1) or trunk circumference increase (data
not shown) . The influence of heading height on length of leader was
not consistent.
Although the data in Table 1 shows that heading hei
critical in regard to total growth, there are other aspe
response to consider. We presently prefer that branches
trees be symmetrically arranged around the vertical axis
leader tree and be spaced far enough apart to avoid limb
when the trees become larger. In contrast, some fruit g
prefer having tiers of branches. Regardless, heading a
example to 24 inches, can limit the number of permanent
ches selected the first growing season to 2 or 3 if vert
of 4 to 6 inches are desired. Furthermore, a whorl of c
shoots may develop on trees headed at 24 inches which co
the leader unless some are removed and/or spread horizon
mechanical device such as wooden, snap clothespins.
ght was not
cts of tree
of apple
of the central
crowding
rowing areas
tree low, for
lateral bran-
ical spacings
losely-spaced
mpete with
tally with a
We found in 1977 that the lateral shoots on Marshall Mcintosh
and Redspur Delicious were more widely spaced on trees headed at
36 inches than those cut at 30 inches at planting. The wider vert-
ical spacing could aid in selection of shoots because of our prefer-
ence of having trees with branches symmetrically arranged around the
vertical axis of the central leader, and with vertical spacings of
4 to 6 inches.
Spur-type strains of Mcintosh and
Delicious tend to produce short lateral
growth the year of planting except dire
behind the heading cut, particularly De
icious. In some apple growing areas he
ing heights of 24 inches are considered
necessary on spur-type trees that are t
be grown free-standing, to insure the d
elopment of the first tier of scaffold
limbs within the desired location on th
tree. Spur-type trees headed at 36 inc
under our conditions, generally produce
short lateral shoots the year of planti
but this higher heading height presents
the opportunity to select more widely-s
shoots. Furthermore, we have observed
spur-strains headed at this height will
duce a good framework of branches durin
the 2nd and 3rd growing seasons even th
the growth was poor the year of plantin
(Figure 1) .
ctly
1-
ad-
o
ev-
e
hes ,
ng
pacec
that
pro-
ough
g
Figure 1. One of the Redspur Delicious/
MMlll trees used in our heading height study
The tree was headed at 36" at planting in
1977. Photograph taken in December, 1978.
-3-
However, this may not occur in apple growing regions where spur-
type trees are very precocious. Fruiting tends to restrict vege-
tative growth and will complicate the process of developing frame-
work branches on spur-type strains and/or weaker- growing varieties.
Removal of Low Lateral Shoots
Early vegetative growth of newly-planted trees is made largely
from carbohydrate reserves in the woody tissue (the same is true
of older trees) . Later in the growing season the carbohydrates
formed by photosynthetic activity are translocated and stored in
the roots and bark for growth next season.
We found in 1977 that growth produced within the vertical
distances of 14.5 and 19 inches from ground level on Marshall Mc-
intosh and Macoun trees added considerably to the total shoot growth
of the tree, particularly on Marshall Mcintosh which produced 2.4
shoots longer than 2 inches within this vertical distance in com-
parison to only 0.78 shoots on Macoun. Low heading at planting com-
bined with removal of growth within 18 to 20 inches of the ground
could produce trees, with little total leaf surface. Leaving low
branches until it becomes necessary to remove them could contribute
substantially to total growth and carbohydrate reserves for growth
the following season. Less distance between the first limb and
the ground can be allowed on varieties like Delicious without inter-
ferring with mowing and weed control practices because they have an
upright growing habit than on varieties like Cortland which have
spreading type growth. Limbs on Cortland within 24 inches of the
ground begin to give trouble when the trees commence bearing.
Recommendations
Tree growth will vary considerably the year of planting regard-
less of heading height. Vigorous growth is the first and most im-
portant step towards the development of well-shaped trees. Good
stock in dormant condition, early planting, and favorable soil con-
ditions are as fundamental as training. Adjust severity of heading
at planting time to the conditions of tree, soil, and season under
which planting is done. Under average or better conditions heading
at 36 inches on 1-year-old whips should produce satisfactory growth
on both spur-type and standard strains. If shoots originating lower
than 18 inches above ground level do not interfere with cultural
practices, leave them. The leaves on these shoots can contribute
to tree growth.
Well-branched (feathered) 1-year-old trees are highly desirable.
When planting this type of tree, remove only broken branches and
remove or restrict shoots with no potential for being a permanent
scaffold limb. Head it at approximately 39 inches.
-4-
Promalin Studies in 1978 and Comments on Trial Use in 1979
Duane W. Greene and William J. Lord
Department of Plant and Soil Sciences
Promalin* is a plant growth regulator containing gibberellin
A. 7 and a cytokinin, 6-benzyladenine , in equal amounts. Its pri-
mary use at this time is to increase the length (^/D ratio or typi-
ness)l of Delicious apples, thereby making them more attractive to
the consumer.
Last year we discussed factors affecting shape of apples and
our preliminary studies with Promalin ( Fruit Notes 43 (3): 4-7).
In this article we report our 1978 findings with Promalin and include
comments to consider when using it in 1979.
1978 Studies
Coverage Growth regulators commonly used in fruit production have
limited translocation from the site of contact with the plant. The
data in Table 1 indicate that the absorption and/or translocation of
Promalin also may be limited.
Table 1. The effect of site of Promalin application to'Richared
Delicious' apple flowers on the L/d ratios of the fruits that
developed from these flowers.
Treatment and microliters
of solution applied^ L/q Ratio
Check .93cy
Petals, 25X .94c
Petals, 150 .99b
Receptacle surface, 25 1.03a
In calyx end, 25 1.03a
^Solution contained 50 ppm Promalin plus 0.05% X-77.
^Numbers in a column followed by different letters are significantly
different at odds of 19 to 1.
^A 25 microliter droplet was large enough to wet the receptacle
surface with no runoff.
*Tradename
: highei , . ^ .
apple. A "typey" Delicious will have an L/d ratio of 1.00 or greater
''^The higher the L/d ratio (length/diameter ratio) the longer the
When a 25 microliter droplet of Promalin was placed either in the
calyx end of the flower or on the receptacle, fruits with large ^/D
ratios were harvested (Table 1). The same amount of Promalin applied
on the petals of a flower produced no response. However, when the
amount of Promalin applied to the petals was increased 6-fold, fruit
elongation occurred. Nevertheless, 150 microliters of Promalin appl-
ied on the petals was not as effective for increasing the E,/D ratios
of the fruits as 25 microliters of Promalin placed on its receptacle,
Therefore, it appears that Promalin must come in contact with the
flower parts that are incorporated into the final structure of the
apple to be most effective.
Surfactants and Adjusting pH of Spray Solution
In general, we do not recommend the use of surfactants with
growth regulators. Many formulated growth regulators (e.g. Alar-85,
Fruitone N, etc.) already contain a surfactant. It doubtful that the
addition of another surfactant to the spray mixture would be of sub-
stantial benefit. In contrast, the Promalin formulation contains no
surfactant. Last year we reported that glyodin and Triton B-1956
(both products that increase wetting) enhanced the response of 'Del-
icious' fruits to Promalin
Table 2. The effects of surfactants and pH modification on the per-
formance of Promalin applied to 'Royal Red Delicious,' Shelburne,
MA. , 1978.
Treatment'
Fruit
per cm
limb circ.
L/D ratio
Fruit
weight (g)
y.ia^
6.0ab
4.9bc
.95c
1.00b
1.04a
154abc
142b
146bc
Check
Promalin
Promalin + Sorba (Mg) +
Glyodin
Promalin + Sorba (Mg) +
Biof ilm
Promalin + Buffer-X
4
4
8bc
Ic
1.03a
1.02ab
156ab
161a
1 pt of each chemical was used per 100 gal. of water. Treatments
applied at a rate of 125 gal/acre at petal fall of the king blossom.
^Numbers in a column, followed by different letters are significantly
different at odds of 19 to 1.
In 1978 trials we made the Promalin solution more acid (to pH 4.0)
with Sorba-Mg2, and added glyodin or Biof ilm (a surfactant). These
spray mixtures, with the pH adjusted were more effective in increasing
the L/D ratio of the fruits than Promalin applied alone (Table 2) .
The mixture containing Promalin and Buffer-X (contains a surfactant
and lowers spray pH) produced fruit elongation comparable to Promalin
A r nTnmf»"r(^ i 3 1 mi t- -r i p>n1- QTTrav
-6-
alone. Thus we have demonstrated in both 1976 and 1978 that certain
surfactants may increase the effectiveness of Promalin and adjustment
of the solution pH appeared to be of additional benefit. Since Pro-
malin is a rather expensive product, we feel that the addition of a
surfactant to the Promalin spray may allow growers to apply less
Promalin per acre or get an enhanced response from that which would
normally be applied.
Other Observations Warm weather prevailed during the bloom period
in 1978. Fruit elongation with an enlargement of the calyx end was
apparent 3-4 days after Promalin application. It is not necessary to
wait until harvest to determine if Promalin caused increased fruit
length in your orchard. Calyx elongation and enlargement is perhaps
most pronounced 1-2 weeks after Promalin application.
The L/D ratio of fruits will vary considerably on a tree. This
is due to the location of the fruit on the tree and their origin
within the blossom cluster. The L/d ratio distribution of fruits
from untreated and Promalin- treated trees is similar (Figure 1).
I .00
L / D RATIO
Figure 1
The L/D ratio distribution of fruits from Promalin- treated
trees and control trees.
7-
This indicates that a Promalin application increases the ^/D ratio
of all fruits on the tree equally. Therefore, a grower can expect
to find some rather flat-looking Delicious on Promalin- treated
trees at harvest time although there should be fewer than on check
trees .
Delicious is not the only cultivar that can be elongated with
Promalin. If pollenizers are located within the rows of Delicious
being sprayed you can expect elongation of these fruit also. In-
creased length of such cultivars as Mcintosh and Cortland in most
cases would not be desirable. Therefore, when applying Promalin
attempts should be made to avoid spraying pollenizer trees where
increased calyx-end length is not wanted.
We observed that the typiness of Delicious was improved re-
markably by Promalin throughout Massachusetts in 1978. A response
of this magnitude has not occurred every year. It was noted this
year that Promalin induced other responses in addition to elongating
fruit. Promalin caused thinning on 20-year-old Royal Red Delicious
when adjuvenants and a buffering agent were included with the Pro-
malin (Table 2) . It is estimated that the crop was reduced slightly
below the load considered to be ideal. Promalin does thin young
Delicious trees much 'more severely than mature trees. Seed number
and fruit diameter were reduced by Promalin in some experiments
but these parameters were unaffected in others. No fruit weight
increases have been observed in our tests even though they have been
shown to occur in other parts of the country. Increased bitter
pit and cork spot were observed this year for the first time when
excessive rates of Promalin were used. We do not feel that this is
a problem that will be encountered under normal circumstances.
However, since Promalin did increase bitter pit and cork spot, in
situations where low fruit Ca levels may occur, the use of this plant
growth regulator may aggravate the problem.
Comments on Trial Use in 1979
We do not discourage the use of Promalin. However, we do
encourage growers to proceed cautiously and apply Promalin to only
a portion of their Delicious trees. As a grower gains more exper-
ience with Promalin applied at his location, on his trees, and in
his sprayer, and is convinced the response is good and the side
affects minimal, then, is the time to move ahead and apply it on
a larger portion of his Delicious trees.
It is not possible to effectively evaluate the Promalin response
(or the response of any other growth regulator) at your orchard
without leaving some trees unsprayed. We suggest that 3 or 4 re-
presentative trees should be clearly tagged and left unsprayed at
2 or 3 different locations in your orchard. This should provide
a valid and unbiased basis for evaluating the effect of Promalin
in your orchard.
-8-
We offer below some comments for your consideration when applying
Promalin in 1979.
1. Use 1 pint of Promalin per 100 gallons of spray solution. Apply
125 to 150 gallons of spray per acre.
2. Apply at king blossom to full bloom. If the temperature is
not expected to rise above 50OF and warmer weather is predicted
within a day or two, delay the application until the first warm
day.
3. If the temperature at the time of application is below 60°F, add
1 pint of Glyodin per 100 gallons of Promalin spray mixture.
Other surfactants may be equally ctrective.
4. Good coverage is important. Calibrate your sprayer and apply
Promalin uniformly throughout the tree.
5. We urge caution if planning to chemically thin trees sprayed
with Promalin. Promalin can thin. We do not know if excessive
thinning can occur should Promalin and chemical thinners be
used the same year.
6. Do not apply Promalin on young trees because thinning may occur.
Perhaps a good rule-of- thumb is not to apply this chemical on
any trees until it is bearing heavily enough to consider chemical
thinning .
7. Do not apply Promalin in combination with other pesticides or
growth regulators.
HARVESTING EARLY RIPENING APPLE CULTIVARS
James E. Anderson
Department of Plant and Soil Sciences
We have observed a tendency of some growers to advance the
picking date for many of the early ripening cultivars. In recent
years we have seen Julyred, Vista Bella and Quinte picked in mid-
July and Paulared in mid-August. Fruit picked too early are often
lacking in color, size and in flavor.
Based on observations at the Horticultural Research Station,
I would recommend picking Vista Bella during the last week of August
and Julyred and Quinte a few days later. Paulared has had better
flavor and keeping quality when picked in late August or early
September.
9-
CHBMICAL THINNING OF APPLES IN 1979
F. W. Southwick
Department of Plant and Soil Sciences
University of Massachusetts, Amherst
When weather conditions during bloom are favorable for bee
activity, many apple varieties will overset if they have an abun-
dance of blossoms. In such instances, chemical thinning with
naphthaleneacetic acid (NAA) , naphthaleneacetamide (NAAm) or car-
baryl (Sevin) avoids a tendency toward biennial bearing and also
helps increase fruit size and color. It involves some risk since
the exact degree of thinning cannot be accurately predicted in
advance. Furthermore, it is realized that attempts to determine
the time of application of the chemical thinning sprays on the
basis of days after petal fall (PF) is not entirely satisfactory.
Prevailing temperatures play a primary role in the rate of young
foliage and fruit development. If the temperatures are cooler than
usual after PF, the time of application should be delayed beyond
the suggested treatment period or vice versa if warmer than average
temperatures prevail.
Weather conditions before and when applying NAA and NAAm
are important. If weather conditions are cool and cloudy or rainy
a week or two before spraying, the leaves developing during this
time will have a very thin cuticle. Under these conditions, NAA
or NAAm would penetrate into the leaf more easily and overthinning
may occur. On the other hand, warm, dry, sunny conditions prior
to spraying would result in a leaf having a thick cuticle that would
impede the movement of NAA or NAAm into the leaf. In this case,
the concentration used may have to be increased to obtain adequate
thinning. Weather conditions before or after application may not
greatly affect the thinning action of carbaryl since the fruit is
its primary absorption site rather than the leaves as in the case
of NAA or NAAm. Light frost which may not injure flowers or young
fruits may injure the foliage and the use of NAA or NAAm at this
time may cause overthinning and increased foliage injury. There-
fore, delay treatment for several days after such occurrences and
reduce the spray concentration and gallonage per tree is thinning
still seems necessary.
In 1978, Mcintosh blossomed quite heavily in Massachusetts and
in many cases were not thinned sufficiently to produce as many
fruits of good marketable size as desired. Consequently, it would
not be surprising if the bloom on such trees in 1979 was only light
to moderate and not require much chemical thinning. A grower should
carefully observe the fruit set in his Mcintosh blocks 7-14 days
after petal- fall (PF) and be reasonably certain that chemical thin-
ning of Mcintosh is necessary on the lighter blooming older trees.
It should be remembered, however, that trees with a light to
moderate bloom may occasionally overset and be more difficult to
chemically thin than trees which blossom and set heavily.
-10-
The use o£ Promalin at full bloom (FB) to improve the "typi-
ness" of'Delicious ' (increase the length to diameter ratio o£ the
fruit) has been found by Dr. Duane Greene and others to be capable
of thinning this variety and its strains. The use of a chemical
thinner such as carbaryl (Sevin) following an application of Pro-
malin, might result in overthinning , excessive fruit size and a
severe yield reduction. 'Delicious' requires freedom from frost
damage and ideal crop pollination conditions for good commercial
yields. It is not desirable to apply a chemical thinner (carbaryl)
or Promalin (which has the potential to reduce fruit set) on young
'Delicious' which invariably set light crops. In blocks of older
'Delicious' trees having a history of oversetting the use of Pro-
malin at FB may be entirely satisfactory but the use of carbaryl
for thinning should be delayed for at least 14 days after PF so
that the need for additional chemical thinning can be reasonably
well determined. If a Promalin treatment at FB or adverse weather
conditions have already limited the initial fruit set there may
be no need to reduce the set further with a post petal-fall appli-
cation of carbaryl. 'Delicious' apples are too valuable for such
risks.
NAA or NAAm thinning sprays applied when the temperature is
less than 650F, are usually less effective. Temperatures of 70-75OF
are necessary for optimum results. When temperatures rise above
850F, there is a rather sharp increase in NAA or NAAm penetration.
If the high temperatures are accompanied by humid conditions that
prevent spray droplets from drying rapidly, overthinning may result.
In this case, the concentration of the thinning spray should be
reduced. Once the foliage has dried after application of these
materials, do not respray if rain occurs shortly thereafter.
NAA or NAAm are best used alone in dilute form. NAA will often
cause more foliage injury and thin more than NAAm or carbaryl.
Carbaryl is the least injurious to foliage. Mixing a wetting agent
with the thinning chemicals may sometimes increase thinning but
invariably increases foliage injury so the addition of a wetting
agent is not suggested.
Since the best day to apply a treatment cannot be accurately
determined in advance, it may be wise to spray a different fraction
of the more valuable mid- and late-season varieties at 3 or 4 day
intervals during the suggested period. An occasional grower may
delay his decision to thin until 3 weeks or more after PF. Apply-
ing NAAm or NAA later than 3-4 weeks after PF may result in no
thinning and reduced fruit size since these compounds have some
temporary fruit size inhibiting action. Carbaryl is usually ineffect-
after about 21 days from PF.
Most commercial formulations of NAA contain 1.0 gram of NAA
per oz. (a few may have 2 grams per oz.). A material containing
1.0 gram per oz. will yield a 10 ppm concentration when 4 oz. per
100 gallons are used. Four oz. of NAAm per 100 gallons will give
a concentration of 25 ppm. It is assumed that the carbaryl (Sevin)
used is a 50% wettable solution.
-11-
A 0.21 dust o£ NAA is available for chemical thinning. The
dusts should be applied dry on dry foliage under good drying con-
ditions to reduce the possibility of foliage injury and overthin-
ning. When applied under such conditions, NAA dusts are often less
injurious to foliage and may reduce fruit set less than comparable
NAA sprays.
Young trees generally require less thinning than older trees.
If treatment seems necessary, it may be desirable to use the lowest
suggested concentration of the chemical thinner, or even reduce this
amount by 1/2 to 1/4.
Early fruiting on the leader of young trees can seriously affect
the shape of the tree. To reduce fruit load until the tree has
reached sufficient size to hold a crop of apples, chemically thin
at PF with carbaryl, 1 lb. plus 15 ppm NAA.
Our suggestions for use of chemical thinners on several apple
varieties are included in the chart on the following p age!
GROWTH REGULATOR SPRAY FOR GROWTH
SUPPRESSION ON APPLE TREES
Duane Greene and William J. Lord
Department of Plant and Soil Sciences
Frequently there are blocks of young, non-bearing trees parti-
cularly Delicious that are growing too vigorously because of lack
_ J- C ■^J1..^ J ^ -: 11,, T „„^^^ +„^„^ ,.,-; 1 1 ^ r^ c- r^ ^-\^a^^ r-^,
Young, non-spur trees . Apply 500 ppm ethephon (1-2/3 pints) plus
1500 ppm Alar-85* (1-1/2 lbs.) in 100 gallons of water 10 to 14 days
after full bloom or when shoots are 4 to 6 inches long.
Young spur trees or older trees with no crop . These trees are
more sensitive to a growth regulator spray than young non-spur trees.
Therefore, apply 300 ppm ethephon (1 pint) plus 1500 ppm Alar-85*
(1-1/2 lbs.) in 100 gallons of water 10 to 14 days after full bloom
or when shoots are 4 to 6 inches long.
In addition to growth restriction, these growth regulators gen-
erally increase bloom the year following their use. Increased bloom
probably will of of no value on bearing trees that lost their crop
due to frost because bloom should be adequate the following year with-
out the use of these growth regulators. However, it may be more dif-
ficult to obtain adequate thinning the year following their use because
of excessive bloom. Additional bloom because of growth regulators use
could be of value on the young, vigorous trees but unfortunately fruit
set may not be increased on Delicious.
We suggest that the ethephon plus Alar-85* spray not be applied
on young trees until they are large enough to bear a crop.
*Trade Name
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-13-
ALTERNATE vs. EVERY MIDDLE SPRAYING FOR APPLE PESTS IN 1978
R. J. Prokopy, K. I. Hauschild, W. J. Manning, and T. R. Bardinelli
Departments of Entomology and Plant Pathology
Earlier, we reported our 1977 findings on the comparative
effectiveness of alternate middle vs. every middle spray treat-
ments in 3 commercial apple orchards (See Fruit Notes 43 (3): 15-19).
Here, we report on our 1978 findings in 4 commercial 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 .
Each of our 4 test blocks was divided into 2 plots of 2-6 acres
each. One plot received the alternate middle program on each spray
date from pink (or petal fall) through last cover. The other received
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. Except in one block, all trees were full
grown - some on M7 rootstock, others on standard. The centers of
the trees were fairly well pruned in all blocks.
To determine the extent of insect pest pressure, we hung traps
in each plot for monitoring tarnished plant bug, European apple saw-
fly, apple maggot, codling moth, redbanded leafroller, and oblique
banded leafroller adults (see Fruit Notes 44 (2): 1-2 for information
on construction of these traps). We caught the following average
numbers per trap:
Pest Every middle plots Alternate middle plots
Plant Bug 5.8 3.3
Sawfly 1.3 2.5
Apple maggot 2.3 0.8
Codling moth 33.0 39.0
Redbanded 50,8 58.3
Oblique banded 2.3 1.8
These results show that pest pressure from tarnished plant bug,
apple maggot, and oblique banded leafroller was greater in the every
middle plots, while pressure from sawfly, codling moth, and redbanded
leafroller was greater in the alternate middle plots.
-14-
To determine the amount of fruit injury caused by these and
other insect and disease pests, we examined at harvest 100 fruits
per tree from 18 trees in each plot. To determine spider mite and
aphid abundance on leaves, we examined 45 leaves per tree on 6
trees in each plot every 3 weeks from April until harvest. The
following were the results:
Avg. % leaves
infested with : Every middle plots Alternate middle plots
1.5
Spider mites
6.1
Aphids
3.8
Avg. ^ fruit
injured by:
Plant bug
0.99
Sawf ly
0.31
Apple maggot
0.02
Plum curculio
0.03
Fruitworm
0.08
Codling moth
0.02
Leafrollers
0.05
Other insects
6.5
0.71
0.43
0.04
0.06
0.14
Total insect 1.50 1.38
Apple scab 0.73 1.61
Black rot 0.21 0.19
Other diseases 0.23 0.20
Total disease 1.17 2.00
Grand total 2.67 3.38
The results show that for all blocks combined, an average of
1.50% of harvested fruits in the every middle plots vs. 1.38% in
the alternate middle plots was injured by insects. Thus, even with
slightly higher pest pressure from sawfly, codling moth, and oblique
banded leafroller, the alternate middle plots averaged slightly less
total insect injury to fruits.
The results also show that an average of 1.17% of harvested
fruits in the every middle plots vs. 2.00% in the alternate middle
plots was injured by disease. This difference was due largely to
one incidence wherein a grower failed to apply a needed spray for
apple scab, and suffered 5.67% fruit scab in the alternate middle
plot vs. 2.83% in the every middle plot. This suggests that proper
timing of fungicide sprays is very important to the success of an
alternate middle program.
Every
Alternate
middle
middle
plots
plots
Difference
191.56
95.78
-95.78
12.25
6.13
-6.12
5.50
2.75
-2.75
-15-
The following is the cost-benefit analysis of the every vs
alternate middle treatments:
Dollar costs/acre
Insecticide, miticide,
and fungicide spray
materials
Labor (3.50/hr.)
Fuel, etc.
Value of fruit loss
owing to insect and
disease injury 67.29 82.39 +15.10
Cost reduction due to
alternate middle
spraying -89.55
This analysis shows that the decreased amount of pesticide applied,
combined with consequent lower cost of fuel and labor for application
of pesticides, even with a slightly greater total percentage of injured
fruits at harvest (3.38% in the alternate middle vs. 2.67% in the
every middle plots) resulted in an overall net benefit (savings) of
$89.55 per acre in the alternate middle compared with every middle
plots .
In summary, our findings to date show that the alternate middle
spray program can result in greatly reduced pesticide usage, effect-
ive pest control, and a greater net profit to the grower. For those
growers interested in trying out the program, we would suggest start-
ing with a one or two-acre block to see how the program 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 effectiveness and possible short-
comings. Present knowledge suggests that the program works best where
the trees are well pruned (open centers) and spaced at recommended
intervals (not wider) .
*****************
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 endorse-
ment is implied, nor is discrimination intended against similar
materials .
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. 44 (No. 4)
JULY/ AUGUST 1979
TABLE OF CONTENTS
Brown-Line Decline of Apple
Poor Apple Growth Disease in Massachusetts
Coating the Trunks of Fruit Trees to Reduce
Winter Injury
Photographs of Nutrient Deficiences
Further Observations of Tree Performance on M.26
Use of Ethephon to Promote Color and Ripening
of Apples in Massachusetts
Pomological Paragraph
BROWN- LINE DECLINE OF APPLE
Daniel R. Cooley/ Ted R. Bardinelli,"'"
2
and William J. Manning
Department of Plant Pathology
A new disease of young apple trees has become evident in the
Northeast in recent years. The disease is called brown-line or
graft union necrosis. Isolated trees in young plantings decline
suddenly, may appear to be girdled, and can be snapped off at the
point of union between scion ana rootstocK. A distinct brown-line
IS evident at tne point of graft union.
Researchers in New York State were able to determine that
the problem occurs most often when MM106 is used as a rootstock
and that it often originates in the nursery. Tomato ringspot virus
(TmRSV) was isolated from diseased trees. The dagger nematode,
Xiphenema americanum ,was also associated with the problem. TmRSV
and the dagger nematode together appear to cause brown-line decline.
TmRSV is found in many plants including raspberry, grape, elder-
berry, florist's geranium, and many common weeds such as dandelion,
chickweed and plantains. The dagger nematode feeds on the roots
of infected plants and carries virus particles to clean non-infected
roots, where new virus infections are initiated. ,
Rootstocks and cultivars differ in their sensitivity to TmRSV.
Some are tolerant and can carry the virus without showing symptoms
or decline. Sensitive plants decline and die over a prolonged
period. Hypersensitive plants respond to TmRSV infections by rapid
destruction of cells near the point of infection. This prevents
the virus from spreading further into the plant.
Dr. James Cummins (Cornell University) believes that union
necrosis results when a tolerant rootstock and a hypersensitive
scion become infected with TmRSV. MM. 106 is highly tolerant to
TmRSV and is usually symptomless. A number of apple cultivars,
particularly Red Delicious, are hypersensitive to TmRSV. When the
virus from the rootstock comes in contact with the hypersensitive
scion, the scion reacts by killing its cells at the graft union.
The result is a brown line at the graft union which prevents water
and nutrient translocation into the scion. The scion dies and is
easily broken off at the graft union.
Cummins has rated a number of apple cultivars for brown-line
sensitivity and rate of decline when grown on MM. 106. Some show
1 2
Extension Technicians, and Associate Professor, respectively.
Department of Plant Pathology, University of Massachusetts, Amherst
01003
-2-
rapid decline, some slow decline and others no decline at all.
His rating is as follows:
Rapid decline Slow decline None
Jerseymac Idared Cortland
Quinte Mcintosh Empire
Red Delicious Spartan Golden Delicious
Rhode Island Greening Stayman Rome Beauty
Tydeman ' s Red York Imperial
Those in the slow decline group may show increased suscepti-
bility to other diseases. Stress caused by TmRSV may be a factor
in predisposing trees to collar rot, caused by the fungus Phyto -
phthora cactorum .
A detection system for TmRSV has been developed, which can
be used to detect the virus before brown-line develops. The test
takes a day to complete and is useful as an advanced warning of
potential problems.
Inarch grafting is one possible way to prolong the life of
trees with brown-line decline. Wood from a rootstock other than
MM. 106 can be used to supply the aerial portions of the tree with
nutrients and water.
Nurseries have made considerable efforts to eliminate TmRSV,
principally by means of soil fumigation to eliminate the dagger
nematode. Proper site preparation by growers is also very helpful
Elimination of weeds and fallowing a year before planting will
help to reduce nematodes in new orchard sites.
Note to Massachusetts Fruit Growers :
If you suspect that you have a brown-line decline problem,
please contact Dr. William J. Manning, Department of Plant Path-
ology, University of Massachusetts, Amherst, 01003.
POOR APPLE GROWTH DISEASE IN MASSACHUSETTS
1 2
William J. Manning, Daniel R. Cooley,
and Ted R. Bardinelli^
Department of Plant Pathology
Poor Apple Growth Disease (PAGD) is a new name for an old
problem. It refers to poor growth or even death of newly-planted
trees, whether planted in old orchard sites or in new orchard
sites (especially those formerly in woodland). Scattered trees,
or trees in small areas may make little growth and die during
the first season. Adjacent trees may be vigorous and healthy.
When new trees do not die, they differ in both size and vigor.
The exact cause of PAGD is unknown. It is probably due to
a combination of factors, both biological and physical. It is
well-known that poorly-drained locations, and those high in or-
ganic matter, especially the remains of old apple root systems,
are especially subject to PAGD. Certain rootstocks, notably
MM106, are also more susceptible to PAGD. A number of nematodes
also contribute to PAGD.
A team of scientists at the East Mailing Research Station
in England feel that PAGD there is caused by the common soilborne
fungus Pythium. Pythium does well in cool moist or wet soils
that are high in organic matter. Dr. Geoffrey Sewell, of EMRS ,
feels that Pythium produces a toxic exudate in soil. This in-
hibits root hair growth and function and this in turn affects
the growth and extension of root tips. Growth of affected trees
is considerably reduced.
We investigated PAGD in 6 new orchards in Massachusetts
last year. Red Delicious, Jerseymac and Mcintosh on M.7A,
MM. Ill, M.26, and MM. 106 rootstocks were involved. The trees
came from different nurseries in different parts of the country.
We brought typical PAGD trees as well as soil from around their
roots back to the laboratory and greenhouse. In the laboratory,
we isolated the following potential root disease fungi: Cylindro -
carpon, Cylindrocladium , Fusarium , Pythium , Rhizoctonia , and Verti -
cillium . These are being used in the greenhouse to determine
whether or not they can cause PAGD in apple rootstocks. Apple
rootstocks have been planted in these soil samples in the green-
house to allow us to follow PAGD under controlled conditions.
We do not know what causes PAGD in Massachusetts. We plan
to continue our laboratory and greenhouse investigations and to
begin field studies in 1979.
Note to Massachusetts Fruit Growers : If you have suspected PAGD
problems, please contact Dr. William J. Manning, Department of
Plant Pathology, University of Massachusetts, Amherst, 01003.
1 2
Associate Professor, and Extension Technicians, respectively.
Department of Plant Pathology, University of Massachusetts', Amherst
4-
COATING THE TRUNKS OF FRUIT TREES TO REDUCE WINTER INJURY
William J. Lord
Department o£ Plant and Soil Sciences
Growers apply white latex paint to trunks of fruit trees
to help prevent winter injury. An application to the south side
of trunks and to the base of lower scaffold limbs reduces the
amount of heat absorbed by the bark, lessens bark- splitting, and
reduces winter injury to crotches of painted branches.
Use only latex water soluble paint. Do not use oil or lead
base paints soluble in paint thinner or turpentine. We have
found that Glidden 3600 and Kyanize Flat White Latex Paint No. 2000,
which are available in Massachusetts are safe to use. However,
most high quality exterior latex paints are probably suitable.
Nevertheless, they should be tested on a few trees before extensive
use because some paints can be toxic, particularly to young peach
trees, causing discoloration and cracking of bark and later, gum-
mosis .
The latex paint may be used either without dilution or as 501
dilution with water. It may be applied using a car wash mitt with
a rubber glove insert, a paint roller, paint brush, or a com-
pressed sprayer (if diluted). When wearing a car washing mitt,
dip your hand into the paint and rub the mitt on the bark. When
painting the lower scaffold limbs apply the latex in the crotches
and out on the limbs for a distance of 6 to 10 inches
Whitewash may also be used to coat tree trunks and branches.
It is more economical than latex and can be applied as a spray.
However, the durability of whitewash will be less than latex
although some formulations of white wash are more durable than
others .
Whitewashes that are used in dairy barns and contain no
insecticides or fungicides or contain an insecticide for fly con-
trol are available from farm supply stores. Application in late
fall seems logical because the fruit has been harvested and con-
tamination of leaves is of no concern.
********************
PHOTOGRAPHS OF NUTRIENT DEFICIENCES
William J. Lord
Department of Plant and Soil Sciences
Nitrogen and calcium are the elements of greatest concern in
Massachusetts orchards. Nevertheless, each year the levels of other
elements are either excessive or deficient in some orchards. The
May/June, 1978 issue of Fruit Notes contained photographs and brief
-5-
descriptions o£ bitter pit and cork spot on apples, magnesium (Mg)
deficiency symptoms on pear leaves, manganese (Mn) deficiency and
toxicity symptoms on apple leaves and wood, and boron (B) toxicity
symptoms on apple leaves. For your information we have included
below photographs and brief descriptions of Mg and potassium (K)
deficiency symptoms on apple leaves and symptoms of B deficiency
on the fruit of Bosc pears.
Mg Deficiency of Apple
*■ Pictured on the left is Mg de-
ficiency symptoms on apple leaves.
Deficiency symptoms are characterized
necrotic (brown) areas between the
veins. The older, basal leaves on
shoots and spurs are usually affected
first, and as the season progresses
the injury symptoms appear on the
younger leaves. The deficiency symp-
toms frequently become apparent in
late July and early August. By late
summer, the shoots on which leaves
show Mg deficiency may be defoliated
except for a few leaves near their
terminals. Mg deficiency increases
fruit drop at harvest.
We consider the optimum levels
of Mg in leaves to be 0.25 to 0.401.
Symptoms of Mg deficiency are infre-
quent in comparison with 15 to 20 years
ago. Nevertheless, our leaf analysis
show that levels are frequently belov/
0.30%. Thereby, the use of high magnesium lime which has been advo-
cated for years, continues to be needed in our orchards.
K Deficiency of Apple
Figure 2 shows leaf
margin burn caused by K
deficiency. This symptom
can be easily confused
with the leaf margin burn
from calcium chloride
sprays. However, unlike
leaf burn from calcium
chloride sprays, the scorch
of leaf margins due to
K deficiency progresses
from the older leaves to
the younger leaves of cur-
rent season shoots as the
season advances. The scorch
may turn gray in color and
leaf fall may occur late in
the growing season. Never-
theless, in 2 instances
leaf analysis was necessary
6-
in 1978 to confirm that the problem was K deficiency rather than
CaClo burn,
B Deficiency of Pear
Occasionally B defic-
iency is so acute in pear
trees that the fruits be-
come malformed and cracked
(Figure 3) . Soil appli-
cations of 13 at the rate
suggested for apples is
effective for preventing
a shortage of this element
in pear trees.
********************
FURTHER OBSERVATIONS OF TREE PERFORMANCE ON M.26
William J. Lord
Department of Plant and Soil Sciences
The 1976 Apple Tree Survey indicated that 8% of the trees
in Massachusetts on size-controlling rootstocks are on M.26. Thus,
this rootstock is common enough for us to observe its performance
under a wide variety of soil and cultural conditions.
Trees on M.26 react more to unfavorable growing conditions
than those on more vigorous size-controlling rootstocks. Trees
within a block may be extremely variable in vigor, with some of
them being weak and/or difficult to train (assuming all the trees
are on M.26). Spur-type trees appear weak when planted on light
soils (Figure 1) , and so do Cortland trees on this rootstock.
The leaders of trees on M.26 often are "droopy" on non-bearing
trees, and these trees tend to lean more frequently than trees on
other rootstocks (Figure 2) . We suggest providing support for the
more troublesome trees rather than trying to correct the problem
with severe pruning. The objective is to maintain a central leader
until the desired tree height is obtained.
-7-
Early, heavy bearing is causing weak growth in some instances
Reduction o£ crop load by hand thinning rather than by chemical
thinning appears to be the best solution to this problem because
tree vigor varies considerably within a block. At present, we
have not seen or heard o£ any problems with fire blight associated
with M.26.
Figure 1 to the left shows
a six-year-old Macspur on M,26
The trees in this block are
planted 14 feet x 18 feet. It
is obvious that on this site
the planting distance is too
wide and that the trees have
low vigor.
In 1976 we planted a block of Rogers Mcintosh and Gardner Deli-
cious (a standard- type strain) on MM. 106, M.7, and M.26 in heavy
soil. The trees on M.26 are very vigorous in comparison to most
blocks in Massachusetts on this rootstock. Mcintosh but not Delicious
were significantly smaller in 1978 on M.26 in comparison to those on
M.M.106 and M.7 rootstocks (Table 1). Mcintosh produced about 0.1
of a bushel per tree in 1978 regardless of rootstock. The Delicious
had a light bloom but produced no fruit.
Growers establishing plantings on M.26 will have to be more
selective of soils than in the past. Shallow soils, with hardpans
that prevent deep rooting, are producing trees that look like "free-
standing M.9's" and the trees are subject to frost heaving. Trees
on M.26 require good deep soils to good drainage and waterhold-
ing capacity and even on these soils they will appear to require
temporary support or permanent support on some sites.
^Ct.
Figure 2 to the left shows
trees on M.26 with poor an-
chorage. Many o£ these trees
in this orchard are now staked
for support.
Table 1. Growth and Yield of Rogers Mcintosh and Gardner Delicious
at the Horticultural Research Center, Belchertown, MA., 1978.
Bloom/cm
Yield
Trunk
Variety
Rootstock
trunk
circumference
(bushels)
circumference
Mcintosh
M.26
4.64a^
0.11a
11.7b
M.7
6.89a
0.12a
12.7a
MT4.106
6.02a
0.12a
13.2a
Delicious
M.26
0.99b
0.00b
10.5c
M.7
0.26b
0.00b
11.6b
MM. 106
0.2 3b
0.00b
10.8bc
Mean in columns not having letters in common are significantly differ-
ent at the 51 level.
-9-
USE OF ETHEPHON TO PROMOTE COLOR AND RIPENING
OF APPLES IN MASSACHUSETTS
W. J. Lord and D. W. Greene
The use of ethephon on early maturing varieties and Mcintosh
to stimulate red color development, increase soluble solids (sugar
content) , and hasten fruit maturity is now a standard practice in
many orchards. However , ethephon must be used with caution . The
mis-use of ethephon or an unavoidable delay in the harvest of ethe-
phon-treated fruit could intensify our current problems of supply
management and poor fruit condition. The placement in marketing
channels of an excessive volume of ethephon- treated 'Mcintosh' apples
that must be sold quickly because of over-maturity could depress
prices .
Successful Use of Ethephon
Ethephon will not completely overcome conditions unfavorable
for development of red color. Ethephon, at 1/4 or 1/2 pint may
add 10 to 30% red color to 'Mcintosh' apples borne on the periphery
of the trees within 7 or 8 days after application. Ethephon at
1/4 pint may promote as much fruit color as a 1/2 pint and will
cause less fruit softening.
Under conditions that are normally associated with poor fruit
color, such as high temperatures, wet and cloudy weather, excessive
vigor or dense trees, ethephon- treated fruit may not develop suffic-
ient red color (50% of the surface having red color typical of the
variety) within 7 or 8 days after application. Furthermore, on
both young and older trees, ethephon may not bring the fruit in the
interior of the tree up to a satisfactory level within 7 days after
treatment. When the fruit are allowed to remain longer on the tree,
however, the color difference becomes greater between the ethephon-
sprayed interior fruit and the non-sprayed interior fruit. It is
of interest to note that 11 days after an ethephon spray (1/2 pt/100
gals of water) in 1974, 66% of the interior fruit on 10-year-old
trees had typical red color and would have graded U.S. Extra Fancy.
On the other hand, none of the interior fruit on the check trees
would have graded U.S. Extra Fancy due to lack of sufficient red
color.
By the time the ethephon fruits in the interior of most trees
obtain adequate color, they will probably be suitable only for juice
or immediate sale because of excessive loss of firmness. The pro-
blem of obtaining adequate color on the interior of large dense
trees can be corrected somewhat by pulling the water sprouts during
the summer and doing some light summer pruning. These procedures
should be followed by spot picking which will lighten the crop load
and permit better light penetration into the interior of the tree
before the application of an ethephon spray.
10-
Use on early maturing varieties . Ethephon is a very useful tool
on early varieties. In general, a single application applied
7-10 days before normal harvest at 1/2 pint per 100 gallons of
water will increase red color development within 4-5 days.
Ethephon has been used extensively on Early Mcintosh, Puritan
and Milton varities by Massachusetts growers with good results.
Rate of color development differs from year to year and block to
block among orchards. Within a block of trees, the red color gen-
erally develops more slowly on the earliest sprayed trees than those
sprayed nearer to the normal harvest date.
This shows that color develops more quickly in some instances
than others and that there is no substitute for a careful daily
check of trees. Early varieties usually ripen unevenly. Therefore,
it may be advisable, for some varieties to make one picking to
remove the riper fruit and then apply ethephon. This should help
minimize the problem of over-ripe fruit at harvest. Some growers
may want to apply ethephon, then pick the ripe fruit that day, or
1 or 2 days later. Although the ethephon label does not state a
specific interval between application and harvest, the practice of
spraying and harvesting within 2 days of application is not recommenc
ed. Harvesting all the mature fruit and then applying the ethephon
to the remaining fruit on the tree is the preferred practice. Ethe-
phon applied alone accelerates fruit drop. Therefore, naphthalene-
acetic acid (NAA) should be used with the ethephon to counteract this
abscission effect.
Use on 'Mcintosh ' . Our suggestions are based on 3 time periods for
sale of ethephon- treated 'Mcintosh' fruits -- prior to normal harvest
time (Labor Day or shortly after), during normal harvest, and after
several months of storage (Table 1) .
The volume of fruits sprayed with ethephon should be based upon
anticipated sales during one or more of these sale periods. The
harvest of ethephon- treated fruit must not interfere with the timely
harvest of fruit for CA since the placement of ethephon- treated fruit
in this type of storage is not recommended. Our data and those from
a regional experiment involving New York, Maine and Massachusetts,
show that ethephon- treated fruit which still are in good condition
will store satisfacotrily in CA, but we are concerned that apples
not in good condition will be stored. However, if labor difficulties
worsen, it may be necessary to extend the harvest season by advancing
it through the judicious use of ethephon on CA 'Mcintosh'.
Fruit to be placed in storage at 32 F must be picked at proper
maturity. Fruit to be sold through January 1, should receive no more
than 1/4 pint of ethephon per 100 gallons of water and be harvested
7-8 days after treatment. Although these fruit should store well
until January 1, they may be softer than Alar*- treated fruit.
'Alar = Alar-85*
-11
Table 1. Suggested use of ethephon for promoting uniform ripening
and red color on 'Mcintosh' apple trees.
Purpose
Compound, timing and rate
Fruit for sale 1st
or 2nd week of
September
Alar* - mid-July at 1 lb/100 gals
ethephon - 8 to 12 days prior to anticipated
harvest at 2/3 to 1 pt/100 gals
plus
2,4,5-TP same timing as ethephon at 20 ppm
Fruit to be picked
during normal har-
vest and held at
32 F in air for
1 month or less
Alar* - mid-July at 1 lb/100 gals
plus
ethephon - 7 to 8 days prior to anticipated
harvest at 1/2 to 2/3 pt/100 gals
plus
NAA or 2,4,5-TP same timing as ethepon spray
at 20 ppmX
Fruit to be picked
during normal har-
vest and held at 320F
in air as late as
January 1^
Alar* - mid-July at 1 lb/100 gals
plus
ethephon - 7 to 8 days prior to anticipated
harvest at 1/4 pt/100 gals
plus
NAA at 20 ppm or 2,4,5-TP at 10 ppm same
timing as ethephon spray
Weather and tree vigor, etc. affect color development. It may be
best to allow 12 days, but be prepared to harvest sooner.
y
2,4,-5TP is preferred if 2/3 pt of ethephon is used because its pre-
harvest drop control capability is greater than that of NAA.
X
If fruit are in good condition, they will store satisfactorily in CA.
*Alar = Alar-85*
********************
POMOLOGICAL PARAGRAPH
Some apple growers are planning to use foliar sprays of nutraphos*
or calcium nitrate in June. We recommend that they switch to calcium
chloride in July and August in order to supply adequate calcium to
their apples. Please refer to page 11 of the March/April 1979 issue
of Fruit Notes for our recommendations on timings and rate of calcium
chloride applications on apple trees.
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
(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. 44 (No. 5)
September / October 1979
TABLE OF CONTENTS
A Preliminary Evaluation of Labor Productivity in Grading
and Packing Mcintosh Apples Grown Under Integrated
Pest Management Conditions
Toxicity of Orchard Pesticides to the Mite Predator
Amblyseius Fallacis 1979 Results
Propagating Your Own Fruit Trees
Some Problems Than Can Reduce Storageability of Apples
Pomological Paragraph
Mailing List Revision
A PRELIMINARY EVALUATION OF LABOR PRODUCTIVITY IN GRADING
AND PACKING MCINTOSH APPLES GROWN UNDER INTEGRATED PEST
MANAGEMENT CONDITIONS
Henry M. Bahn
Extension Specialist in Farm Management
Department of Food and Resource Economics
University o£ Massachusetts, Amherst
In 1978 a pilot program o£ integrated management for apple
pests was initiated in Massachusetts. Developed by the Coopera-
tive Extension Service and Departments of Entomology and Plant
Pathology, the program was designed to reduce pesticide usage
while maintaining high quality fruit production. Selective pest
management may result in lower production costs for pesticides,
equipment and labor but may also result in higher grading and pack-
ing costs and less marketable fruit due to increased damage levels.
The 1979 summary for the Integrated Pest Management (IPM) pro-
gram cited net benefits to the participating producers. It is un-
clear, however, whether changes in insect and disease damage levels
as a result of incorporating IPM growing methods will affect grading
and packing costs. Studies in Michigan, the Appalachian area, and
Washington State have all indicated that quality of fruit is a major
influence on grading and sorting costs.
Because the hand packing method is specific to the Northeast,
a thorough packing cost analysis should be undertaken. V/e plan to
undertake such a study in Spring, 1980. Meanwhile, preliminary
applied study of the relationship between damaged fruit and grading/
packing costs was completed in Spring, 1979. By monitoring and
comparing the actual packing time requirements for Mcintosh apples
grown under IPM and conventional practices, some measurement of
differences in labor productivity in grading and handling was est-
abl ished.
Yields and size of fruit produced have not been found to be
significantly affected by growing under IPM methods. The major
difference between IPM and conventional practices is expected to
be in the quality of harvested fruit, i.e., levels of insect and
disease damage. For the Massachusetts IPM pilot study, comparative
data are not available for disease damage levels, but insect damage
was reduced from 4.721 in the controls to 2.64% in the IPM samples.
This reduction was not expected but it should be noted that this
finding is based on only one year's data and a relatively small
sample .
Methods and Procedures
To compare IPM versus conventional fruit packing costs and
labor productivity, several orchards which participated in the 1978
IPM pilot program were sampled during IPM and conventional packing
operations. The quantity of orchard run apples handled, culls
-2-
removed and quality of daily packout were noted. Total labor
requirements for each day's operation for direct labor components
were monitored. A simple comparison of labor productivity and
labor costs was made for the two types of apples. This analysis
did not identify total packing costs for either IPM or conventional
fruit, but rather, the relative difference in labor productivity
and costs.
Results
The results of the comparative analysis indicate that (1) IPM
apples sampled had a higher sortout (cull) rate than the control
fruit, i.e., a larger percentage of the control apples was packed
as extra fancy or fancy; and (2) IPM fruit required more time per
bushel for grading/packing and had correspondingly higher grading
and packing costs.
Fruit Injury Levels
Participating IPM and check orchards were monitored throughout
the 1978 growing and harvesting season. Numbers of spray applicat-
ions, dosages, pest populations and injury levels were recorded.
A review of the records for the orchards sampled for this study
indicates that IPM blocks sustained an average of 4.6°o pest-injured
fruit, while control blocks sustained 4.0% injury. Thus, the pest
injury rate was 16.7% higher for the IPM fruit for the sampled
orchards. For a pack of 1,000 bushels, this difference would result
in 6.6 extra bushels of damaged fruit for the IPM samples.
Labor Requirements
A typical hand packing line for Mcintosh apples would consist
of six packer/graders, a worker to supply fruit to the line and to
supervise, and a carton handler to fasten and remove filled cartons.
Alternatively, all activities other than grading/packing could be
undertaken by one individual.
Table 1 depicts the average workday for the packing lines
sampled. The workday is typically 7.5 hours with a half hour lunch
break and morning and afternoon breaks of 10 to 15 minutes. Although
workers are paid for the 7.5 hour workday, the packing line is not
operated during lunch and rest breaks. These idle periods were sub-
tracted to determine the actual number of worker hours available per
day.
3-
Table 1. Average labor requirements -- Mcintosh apple hand grading
and packing.
Packing Line Operation
Workday 7.5 hours
Less lunch break @ .5 hrs. .50
Less rest breaks 2 @ .234 hrs. . 47
Packing Line Operation 6.53 hours
Personnel Requirements
IPM
Grader/Packers 5.8^ each @ 6.53 hrs. 37.87 hours
Supervisor/Carton Handlers 1.2^ each
@ 6.53 hrs. 7.84
Total Worker Hours Per Day 45.71 hours
Control
z
Grader/Packer 5 each @ 6.53 hrs. 32,65 hours
Supervisor/Carton Handlers 1.2^ each
@ 6.53 hrs. 7.84
Total Worker Hours Per Day 40.49 hours
Fractional number of workers is due to averaging data from all
sampled packing houses.
According to Table 1, the IPM packing line used a larger number
of grader/packers (average of 5.8) than the control (average of 5).
Ordinarily, the number of grader/packers would be the same. However,
on the same days the samples were taken, several control packing
lines were not operating at full grader/packer capacity.
The problem does not affect the comparison of labor productiv-
ity for grader/packers, since productivity is based on volumne of
apples packed. The supervisor/carton handler's productivity will
be lower for the control fruit, however, since all packing lines
were operating at normal levels for these personnel.
Labor Costs
The calculations for labor costs presented in Table 2 are
straightforward, being merely the average wage rates on a per
hour basis for the normal 7.5 hour workday.!/ In those cases
where a premium or piece rate was paid, the wage rates were
based on estimated hourly averages for grader/packers for each
packing line.
Table 2. Average daily direct labor costs -- Mcintosh apple
hand grading and packing.
IPM ~~
Grader/Packers 5.8^ each @ $3.42 x 7.5 hrs. $148.77
Supervisor/Carton Handlers 1.2^ each (? $6.29 x 7.5
hrs . 56.61
Total Direct Labor Costs $205.38
Control
Grader/Packers 5 each @ $3.42 x 7.5 hrs. $128.25
Supervisor/Carton Handlers 1.2 each @ $6.29 x 7.5
hrs . 56 . 61
Total Direct Labor Costs $184.86
^Fractional number of workers is due to averaging data from all
sampled packing houses.
Comparative Results
After computing average labor requirements and costs, a
comparison was made based on the number of bushels of fruit dumped
and packed. In every case, the grader/packer cost for IPM fruit
exceeded the cost for control fruit. This caused total direct
packing costs to be higher for IPM apples in each case. Super-
visor/carton handler costs, on the other hand, were less for IPM
apples. This stems from the fact that the control packing lines
had less grader/packers working and therefore dumped fewer apples.
-'The direct labor costs used here do not include fringe benefits,
taxes or insurance payments.
Control
189,
.0
23.
,0
87,
.83
.244
•
197
047
-5-
The supervisor/carton handlers for the control packing lines were,
in effect, underemployed since those lines were operating at less
than normal capacity. Average comparison data are presented in
Table 3.
Table 3. Comparison of labor productivity in grading and packing
IPM pnd control Mcintosh apples.^
Activity IPM
Apples Dumped (bu.) 204.0
Sortouts (bu.)^ 29.4
Packout (I) 85.58
Labor (hrs. per bu. packed) .262
Grader/Packers .217
Supervisor/Carton Handlers .045
Labor Cost ($ per bu. packed) 1.176 1.113
Grader/Packers .852 .773
Supervisor/Carton Handlers .324 .340
z
Average data for all packing operations sampled.
y
Includes utility grade and culls.
The IPM apples exhibited a sortout rate 18.4% higher than the
control fruit sampled. This is only slightly higher than the
difference between pest injury levels discussed earlier (16.7%).
The difference may be due to more critical inspection by the grader/
packers, some unidentified deterioration of the IPM fruit during
storage, or sampling error since the control fruit packed was not
necessarily the control fruit monitored during growing and harvest.
The grading/packing operation took slightly over 10% longer per
bushel packed for the IPM apples. The Washington State study mention-
ed earlier found that grading time increased as cull rates increased.
The study results presented in Table 3 are consistent with those
findings .
By implication, if grading/packing time per bushel packed in-
creases, grading/packing costs should increase relatively. Such an
increase in costs was observed, being just over 10% higher per
bushel for the IPM fruit than for the control sample.
Implications and Conclusions
The data analyzed in this study add support to the hypothesis
that grading/packing costs increase as insect and disease injury
rates increase. Conversely, higher quality fruit is expected to
have lower overall grading and packing costs.
The scope of this study is severely limited by the small sample
size involved. A very small number of participating grov;ers were
sampled and multiple observations were made of some participants.
Thus, the data are subject to bias and should be considered as only
preliminary results. Because of these limitations, management con-
clusions should not be based on this report. A more complete
sample should be taken on the apples grown in 1979 and a more soph-
isticated statistical analysis should be undertaken to identify
relationships between fruit injury levels and grading/packing costs.
On a general level, however, labor productivity of graders and
packers does appear to be lower for IPM grown apples. Higher quality
fruit, with the accompanying lower cull rates, can apparently be
packed more quickly and at loxver per bushel direct costs than fruit
with a higher incidence of pest damage. Future research is needed
to determine a break-even point between production cost savings
of integrated pest management programs and possible increases in
packing costs due to increased pest injury.
**********
TOXICITY OF ORCHARD PESTICIDES TO THE
MITE PREDATOR AMBLYSEIUS FALLACIS -1979 RESULTS
Robert G. Hislop and Ronald J. Prokopy
Department of Entomology, Femald Hall
University of Massachusetts
Amblyseius fallacis is the most important predator of red and
two-spotted mites in commercial apple orchards in Massachusetts.
It was found in 23 out of 26 such orchards surveyed by us in 1976.
During the past three years we have been assessing the impact
of pesticides on the survival of A. fallacis in orchards ( Fruit
Notes 45 (4): 5-8) as well as in the laboratory ( Fruit Notes 45 (5):
14-18). We discovered that this predator can readily survive some
key pesticides such as Guthion (azinphosmethyl) and Imidan (phosmet)
at recommended concentrations, but is highly susceptible to certain
other pesticides. For example, Zolone (phosalone) at recommended
rates virtually decimated field populations of A. fallacis , thereby
creating large spider mite outbreaks.
Here, ive summarize our most recent laboratory results, which
deal with pesticides not heretofore tested on a Massachusetts strain
of A. fallacis . Two of the insecticides tested (the synthetic
pyrethroids Pydrin and Pounce) have experimental permits only; we
screened them to determine their effects should they become available
for possible future use in integrated pest management programs in
Massachusetts. Because A. fallacis spends considerable time in the
orchard understory, especially m spring and early summer, careless
use of herbicides can be highly detrimental to predator populations.
This is the reason for inclusion of herbicides in our pesticide screen-
ing program.
Methods
As in our previous laboratory trials, we employed here the
slide dip assay technique in which A. fallacis adults (Bishop strain)
were dipped into orchard concentrations of pesticide. As before,
we determined the percent mortality 48 hours after dipping.
Results
The results are presented in Table 1. Insecticides which
proved highly toxic (70-100-0 mortality) to A. fallacis were Lannate
(methomyl) 1.8 EC, Cygon (dimethoate) 2.7 EC, Pydrin ^f envalarate)
2.4 EC, and Pounce (permethrin) 3.2 EC. Penncap M (parathion) 2 FM
was within our range of low toxicity (0-30% mortality). Although
A. fallacis has received little exposure to Penncap M in Massachusetts,
this low toxicity could very well have been pre-selected by long-
term exposure of A. fallacis to such chemically closely related mater-
ials as Imidan (pEosmet) 50 WP and Guthion (azinphosmethyl) 50 WP .
The high toxicity of the first four materials does not favor their
use in integrated pest management programs.
The fungicide Karathane (dinocap) 25 WP was within the moder-
ately toxic range (30-70% mortality), while Polyram 80 WP, Phygon XL
(dichlone) 50 WP and Manzate D 80 WP were of low toxicity. Of these
materials, only Karathane would be likely to have a negative impact
on orchard populations of A. fallacis .
Of the herbicides tested, Ammate X (ammonium sulfamate) was
highly toxic to A. fallacis , while Dowpon M (dalapon) was of low
toxicity. Dowpon M and Princep (simazine) 80 WP (see Fruit Notes
43 (5): 14-18) are thus the herbicides recommended for use in inte-
grated pest management programs. When applying herbicides, be care-
full to preserve at least 50% ground cover under the trees to provide
-8-
a habitat suitable for A. fallacis buildup.
With these results, the list of pesticides now known to have
highly toxic effects (at recommended orchard rates) on Massachusetts
strains of A. fallacis includes Zolone (phosalone) Systox
(demeton) 6 EC, Sevin (carbaryl) 50 WP, Diazinon 50 WP, Lannate,
Cygon, Pydrin, Pounce, Carzol (formetenate hydrochloride) 92 SP,
Paraquat CL (paraquat). Roundup (glyphosate) and Ammate X. (Also,
(benomyl) 50 WP has strong anti-reproductive effects on A. fallacis ) .
Those known to have moderately toxic effects include Phosphamidon
(dimecron) 8 EC, Kelthane (dicofol) 35 WP, and Karathane. Until
we learn more about possible ways in which the detrimental effects
of these materials can be reduced, we discourage their use by orchard-
ists aiming at an integrated program of spider mite management except
where needed in emergency situations, such as San Jose scale or
tentiform leafminer outbreaks.
Table 1. Toxicity of pesticides to Amblyseius fallacis (Bishop
strain) at recommended orchard rates .
Material
Rate/100 gals. Mortality, ^o Toxicity Rating
INSECTICIDES
Lannate [methomyl) 1.8 EC
Cygon (dimethoate) 2 . 7 EC
Pydrin (f envalarate) 2.4 EC
Pounce (permethrin) 3.2 EC
Penncap M (parathion) 2 FM
FUNGICIDES
Karathane (dinocap) 25 WD
Polyram 80 WP
Phygon XL (dichlone) 50 WP
Manzate D 80 WP
HERBICIDES
Ammate X ["ammonium sulfamate)
Dowpon M (dalapon)
0.5 pt.
100
High
1.0 pt.
96
High
2.6 oz.
100
High
2.1 oz.
100
High
2.0 pts.
12
Low
0.5 lb.
46
Moderate
1.5 lbs.
7
Low
0.5 lb.
5
Low
1.5 lbs.
8
Low
60 lbs.
78
High
2.5 lbs.
26
Low
-9-
PROPAGATING YOUR OWN FRUIT TREES
James F. Anderson
Department of Plant and Soil Sciences
Fruit growers in many areas o£ the country have experienced
difficulty in obtaining nursery trees. I know of several Massa-
chusetts growers who have waited 2 or more years to receive tree
orders and then have had to accept substitutions as to size and
make-up of the tree ordered. Reasons suggested for this scarcity
of fruit tree nursery stock are: (1) an increased demand for fruit
trees due to both new and replacement plantings; (2) a tendency to
use closer planting distances in many of these plantings; (3) loss
of both understock and budded trees in the nursery due to adverse
weather conditions; (4) shortages of certain understock (1 or 2
favorable and often preliminary reports on a new rootstock will
create a demand that may take several years to satisfy) ; and (5)
lack of qualified budders resulting in poorer stands in the nursery
row.
Because of this scarcity of nursery stock a number of growers
have indicated an interest in propagating their own fruit trees.
For those individuals contemplating such an operation I would sug-
gest that they secure and read the following publications: New
York Food and Life Sciences Bulletin, No. 19, June 1972; Tree Rais -
ing on the Fruit Farm-An Essay on Management . by James C. Cummins,
and New York State Agricultural Experiment Station Bulletin 817,
May 196 7: Propagating Fruit Trees in New York by R.D. Way, F. G.
Dennis and R~! M. Gilmer . Both are available from the Department
of Pomology and Viticulture, New York State Agricultural Experi-
ment Station, Geneva, NY 14456. There is a mailing and handling
charge of 20 cents for each publication. Checks should be made out
to the New York Agricultural Experiment Station.
It is not unrealistic or impossible for the orchardist to pro-
pagate his own trees if he is willing to carry out the necessary
nursery operations on a timely basis. Those growers who currently
find it difficult to complete their orchard operations on time should
not attempt to propagate their own trees.
An open site that has good air drainage and a well drained
fertile soil is best suited for the nursery site. It would be
desirable for the nursery to be located near the residence or
orchard office area to provide for more efficient management and
possible protection from deer damage. An isolated planting is more
apt to be neglected. The orchardist growing his own nursery trees
might use the following tree schedule:
1. Order the desired rootstocks at least 1 year in advance of plant-
ing as the demand is often greater than the supply.
-10-
2. Prepare the land at least a year in advance o£ lining-out of
the rootstocks, soil fumigation might be a part of this pre-
paration.
3. Line-out the rootstocks in early-Spring, April if possible.
The rootstocks are set 8 to 10 inches apart in the row and
the rows are 42 to 60 inches apart. The spacing between rows
is determined in part by the equipment to be used.
4. Bud the trees, beginning in late July or early August. The
bud wood should be collected just prior to budding.
5. During this first year the trees should be sprayed to control
insects and diseases and the soil cultivated to suppress weeds.
6. The following spring the top of rootstock is cut-off just above
the bud and any suckers arising from the rootstock are removed.
This allows the shoot arising from the inserted bud to make maxi-
mum growth. Suckers continuing to arise from the rootstock
portion of tree should be removed by rubbing them off with the
fingers .
7. The trees should be sprayed to control insects and the soil
should be cultivated to control weeds during this second season.
Herbicides might be used for weed control.
8. The trees may be dug in the late fall (November) where suitable
storage conditions are available, or the following spring. DO
NOT STORE THEM IN YOUR APPLE STORAGE, since gasses from the fruit
may make them break dormancy during storage.
The various steps necessary in the propagation of fruit trees
are described in detail in Bulletin 817.
Some Additional Points
1. The propagation of patented varieties is restricted. Growers
wishing to propagate such a variety must obtain permission from
the holder of the patent rights to it.
2. Cut budwood from trees that are healthy, vigorous, productive
and true- to- type . When cutting in an orchard be especially
careful, as most rows include pollenizer varieties and some
may include partially top-worked trees. Keep your eyes openi
3. All nursery rows should be carefully staked and labelled so
as to indicate both rootstock and variety. You should also
maintain a nursery register indicating all pertinent information,
4. Budding a few trees is fun; budding for a day is hard work. The
novice should start on a small scale.
-11-
SO^ffi PROBLEMS THAT CAN REDUCE STORAGEABILITY OF APPLES
William J. Bramlage
Department o£ Plant and Soil Sciences
At harvest time, a fruit grower not only must gather the
crop from the orchard, but he must also make dozens of decisions
that will ultimately affect the quality of the product that reaches
consumers. To produce a quality product, these decisions must be
made with an understanding of the principles of fruit behavior and
handling. Last year I reviewed what we think are the most import-
ant principles as well as our basic recommendations for apple
storage ( Fruit Notes 43, September/October issue 1978: pp 1-5).
We urge you to take a few minutes and re-read this review of the
"basics", because we believe that the growers who stick as close
as possible to these "basics" are the ones who year-in and year-out
have the fewest storage problems.
Keeping these basics in mind, I will develop here some of
the information and ideas about fruit handling that have come to
my attention in recent months. These considerations may help you
avoid storage problems.
Bruising is an important though often neglected factor in
the behavior of fruit after harvest. Beside disfiguring the fruit,
bruising also causes it to produce large amounts of ethylene, the
hormone gas that causes ripening to begin. Dr. L. M. Massey, Jr.,
of the New York Agricultural Experiment Station in Geneva, has
demonstrated the importance of bruising. If apples are picked be-
fore ripening has begun, they are most suitable for long-term stor-
age. But, if these apples have been extensively bruised during
picking or handling, their potential can be shortened substantially
because ripening will begin almost immediately. Even when apples
are picked after ripening has begun. Dr. Massey found that extensive
bruising increased their rates of softening and sugar loss during
storage. He also found what we too have observed: bruising does
not lead directly to breakdown or other apple disorders during
storage. Careful harvesting and handling will improve fruit stor-
ageabil ity .
Bruising is also a major cause of fruit loss after packing.
We reported last year ( Fruit Notes 43, September/October issue, 1978
pp 5-7) some results from tests by Dr. George Mattus in Virginia
on the amounts of bruising that result from dropping of cartons,
and of the influence of different kinds of packaging on this bruis-
ing. Dr. Mattus has continued these tests and has generally con-
firmed last year's findings. Packages differ significantly in the
amount of bruising caused by drops, but the basic message is: Don' t
drop cartons of apples, not even a little bit!
-12-
Scald is always a worry during apple storage. We did
not have serious scald problems in New England last year, but
in many parts of North America scald caused very serious losses.
The reason was probably high temperatures during the harvest season- -
high temperature shortly before harvest increases the susceptibility
of apples to scald. When susceptibility is high, conventional scald
control measures may not be effective. If high temperatures have
prevailed immediately before harvest, and especially if coloring
is poor and you know that your nitrogen levels tend to be high, you
should take extra precautions to thoroughly apply scald inhibitors
at maximum dosage but not above maximumi You should also be
extra careful with storage management to delay ripening as much as
possible, since scald development comes with ripening, and make
every effort to market the fruit as early as possible. We have
also found that a high calcium level in the fruit can reduce scald
development .
Your fertilizer program can certainly influence your storage
problems with apples. In particular, if nitrogen or potassium are
quite high in your trees, or if calcium is low, you may encounter
much greater problems during storage. The importance of nutrition
is dramatically illustrated by a system now used in England to
determine length of storage. In this system, samples of apples are
collected from each orchard 2 weeks before harvest and analyzed for
5 mineral elements. Based on the analysis, the grower is informed
of the maximum length of time he can store his apples and still
market them cooperatively. A simpler system, based solely on fruit
calcium analysis, is also being used for export apples in New
Zealand.
We plan to test the English system this year, but in the ab-
sence of a fruit analysis, observation of your fruit can help avoid
problems. If your trees have lush, dark green foliage and the apples
are large and poorly colored, nitrogen levels are probably high and
the fruit should not be stored late. If you see significant amounts
of cork spot or bitter pit on the apples, and especially if the
fruit are large, calcium levels are probably low and the fruit should
not be stored late. In either case you should consider a post
harvest dip treatment in calcium chloride (CaCl2). CaCl2 is com-
patible with scald inhibitors and fungicides, so the treatment can
easily be accomplished if you are dipping the fruit anyway. A high
CaCl2 concentration (24 to 32 lbs/100 gal) is essential for success,
since most of the calcium is absorbed into the fruit from residues
during storage. This high CaCl^ concentration is corrosive and can
cause skin injury on the fruit, but injury is much more of a pro-
blem in warmer areas, such as Maryland and Virginia, than it has
been in New England.
Postharvest CaCl^ dips have repeatedly been shown to reduce
softening and storage disorders of apples, and use of these dips
is growing in many apple-producing regions. Research is also cur-
rently being conducted in several areas on the infiltration, by
either pressure or vacuum, of large amounts of CaCl^ into apples,
but many questions remain to be answered about this method. We think
that there is much potential benefit to be gained from CaCl2 dips.
-13-
There is growing evidence that use o£ growth regulators during
the summer can have important influences on the fruit during storage.
Ethrel* can of course cause earlier ripening, even when it has been
applied long before harvest. Use of Alar* continues to be contro-
versial its host of effects on apple development makes assessment
of its overall effect hard to evaluate. During the past 2 years
extensive studies have been carried out in a number of areas, but
especially in New York and Maine, and they have failed to show con-
sistent effects of Alar* except for greater firmness at harvest and
preharvest drop control. Our own results have also been inconsist-
ent. In the previous 2 years we found greater breakdown in Alar*-
treated fruit, but last year there was no more breakdown with Alar*
than without it. We believe that Alar* can produce greater break-
down under certain conditions, but that this problem can probably
be overcome by harvesting at the proper time. Do not delay harvest
of Alar-treated apples ; they should be harvested at the same time
as if Alar had not been used.
We now see evidence that Promalin* may reduce storageability
of apples. Dr. Duane Greene has found in his experiments here
with both Delicious and Tlclntosh that Promalin increased the amount
of breakdown after storage, even when applied at low concentrations.
However, Dr. Warren Stiles has found no detrimental effects from
Promalin* on Mcintosh in Maine. Obviously, we have much to learn
about the effects of Promalin* but it may be that the cooler temper-
atures in Maine account for the differences in results. Nevertheless,
we believe that growers who have used Promalin* should be extra
cautious about long-term storage of these fruit.
The ability to delay ripening of apples for almost a year is
a marvelous thing. It is even more marvelous for Mcintosh, which
is almost a summer variety. Successful long-term storage requires
a lot of things being done right, and the capacity of the fruit
to withstand this "test of time" can easily be eroded. Most of
what has been written above has dealt with efforts to protect against
these eroding influences. In conclusion it should be said that
from the standpoint of fruit quality nothing is gained by long-term
storage. Furthermore, the cost and scarcity of energy are sure to
lead to greater efforts to conserve energy during storage operation.
An obvious way to conserve energy is to store for shorter lengths
of time, and just as obviously, a way to do this is to market more
of the crop in the Fall. Ethrel* offers the means for starting
harvest sooner, and we think that once Fall marketing has begun it
should be utilized much more fully than is presently being done.
A
Trade name
14-
PCMOLOGICAL PARAGRAPH
William J. Lord
Department o£ Plant and Soil Sciences
Benlate* (benomyl) -tolerant storage decays . D.A. Rosenberger,
Plant Pathology, Cornell University, NY reported in Cornell Fruit
Handling and Storage Newsletter , July 1979 that some blue mold
and gray mold rot fungi are tolerant to Benlate. Isolates obtained
at several packing house-storages in the Hudson Valley, Champlain
Valley, and in the Lake Ontario areas showed that the proportions
of Benlate- tolerant to Benlate-susceptible fungi varied greatly
among locations.
Tests conducted last fall showed that a combination of 8 oz.
Benlate and 1 lb. Captan per 100 gal. provided much better control
of blue mold than did Benlate alone where Benlate- tolerant spores
were present. Therefore, when using Benlate as a post-harvest dip
or drench, we suggest adding Captan at the rate of 1 lb. per 100
gallons .
***********
All pesticides listed in this publication are registered for
suggested uses according to Federal registrations and State Laws
and regulations in effect n 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 LIVESTOCK. DISPOSE OF EMPTY CONTAINERS
RIGHT AWAY, IN A SAFE MANNER AND PLACE. DO NOT CONTAMINATE
FORAGE, STREAMS AND PONDS.
15-
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University of Massachusetts
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University of Massachusetts
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NOTES
PREPARED BY
DEPARTMENT OF PLANT AND SOIL SCIENCES
COOPERATIVE EXTENSION SERVICE,
UNIVERSITY OF MASSACHUSETTS, UNITED
STATES DEPARTMENT OF AGRICULTURE AND
COUNTY EXTENSION SERVICES COOPERATING.
EDITORS
W. J. LORD AND W. J. BRAMLAGE
Vol 44, No. 6
NOVEMBER/ DECEMBER 1979
TABLE OF CONTENTS
Carbon Monoxide Accumulation in CA Storages
Evaluation of Delicious Strains
Spur-Strains of Mcintosh
Variability in Macspur Strain of Mcintosh
1979 Disease Results for the Massachusetts
Apple Pest Management Program
Integrated Management of Apple Pests in
Massachusetts Commercial Orchards - 1979
Results: Insects and Mites
FRUIT NOTES INDEX FOR 1979
CARBON MONOXIDE ACCUMULATION IN CA STORAGES
G. David Blanpied, Pomology Department
Cornell University, Ithaca, New York
Carbon monoxide (CO) is a colorless, odorless gas which causes
numerous deaths each year. Almost all of these deaths are caused
by CO in the exhaust from internal combustion engines. Human res-
ponse depends upon the concentration of CO and the length of exposure
to it. For example, you wouldn't notice 100 ppm of CO if you were
exposed for 3 hours, but after 8 hours you would be nauseous and
have a headache. CO at 900 ppm would cause the same symptoms after
1 hour. Exposure to 4000 ppm of CO would be fatal in less than 1
hour .
The possibility of CO in CA storage was brought to my attention
this past spring by Warren Stiles. He reported that workers in 2
Maine apple packinghouses had developed headaches and had become
nauseous after working in an area adjacent to the door of a newly
opened CA room. At both establishments an oxygen burner had been
used to reduce the oxygen concentrations in the CA rooms. Analyses
of the air in the areas surrounding the newly opened CA rooms revealed
the presence of CO at concentrations which could cause CO poisoning
symptoms to develop after exposure for several hours.
We analyzed the atmosphere in 10 Hudson Valley CA rooms that
had been "burned" with Anderson, Arcat, and SMB burners at harvest
and/or after resealing in the spring. The 5 rooms that had been
"burned" in the fall had 50-200 ppm of CO. The 5 rooms that had been
recently "burned" after resealing had 250-1800 ppm of CO.
Early this summer we sealed an empty CA room at Ithaca. With
a new catalyst bed in an Arcat the room was "burned" to 3% oxygen.
We learned that most of the CO was produced when the oxygen in the
room was between 5 and 3t. Also, the faster the flow of propane to
the burner, the higher the amount of CO that accumulated in the room.
The take-home lessons from these observations are clear. If
you are lowering the oxygen in a CA ro'om \\fith an open- flame burner,
such as an Anderson burner, thoroughly ventilate with fresh air
the area adjacent to the discharge from the CA room. When you open
a CA room in preparation for removal of apples, ventilate with fresh
air the area around the CA door if people will be working nearby.
**********
EVALUATION OF DELICIOUS STRAINS
William J. Lord, Richard A. Damon, Jr., James F. Anderson
and
Franklin W. Southwick
University of Massachusetts, Amherst
A planting was established in 1964 at the Horticultural Re-
search Center, Belchertown, MA to evaluate the following Delicious
strains on M7 rootstock: Richared, Turner Red, Jardine Red, Royal
Red, Gardner Red, Red Prince, Rogers Red, Sturdeespur (Miller
Strain), and Starkrimson (Bisbee strain), the last two being spurs.
The experiment was a randomized block design with 6 single-tree re-
plicates. The trees were planted at 20 feet by 30 feet spacing.
Summarized below are our findings to date. The full report is pub-
lished in the 1979 Proceeding of the Mass. Fruit Growers' Association,
Volume 85, pp 76-83~] ^ '~
Color Evaluations
Rogers Red, Royal Red, Starkrimson, and Sturdeespur have rated
best in color evaluations. Gardner Red fruits have less intense red
pigmentation than these strains and should be suitable for those who
like less color intensity. Red color on Turner Red lacks somewhat
in uniformity and is less intense than on Starkrimson, Royal Red,
Sturdeespur, and Rogers Red. The fruits of Jardine Red are blush
with some striping but lack the intensity of red needed to meet
present standards for color.
Production
Why Delicious is unproductive in the eastern United States was
the subject of a conference hosted by the USDA in 1977. Researchers
in attendance stated that strains differ in fruitfulness but there
was a lack of supportive data. It was reported that spur-type strains
perform somewhat better than standard- type strains and that Red Prince,
Richared, and Royal Red in some apple growing areas are less productive
than other strains.
We lost 2 of our Red Prince trees in 1972, but by statistical
techniques it was possible to obtain an estimate of yields. Thus,
the productivity of Red Prince in comparison to other strains in the
test is reported.
Early Production : Yield data were first recorded in 1970 when
the trees were in their 7th year, and at this time the strains averaged
at least a bushel per tree. In 1970 production per tree was similar
among strains. Gardner Red produced more fruit per tree than either
spur strain in 1971. In 1972, Turner Red was more productive than the
spur strains.
-3-
Although yield per tree favored the more productive standard-
type strains in 1971 and 1972, higher tree numbers per acre are
possible with spur trees. Actual spacing trials provide the most
reliable estimate of yield per acre. In absence of these, we
arrived at theoretical tree spacings for the strains by using tree
spread in 1978. Some trees of the standard- type strains have re-
quired pruning to keep them in their allotted space; as a result all
standard- type strains averaged 19' spread. Tree spread of Sturdee-
spur and Starkrimson averaged 15' and 14', respectively.
Theoretical yields per acre were determined by multiplying
average yield per tree by trees per acre. The theoretical yields
showed that Sturdeespur was more productive in 1970 and that there
was no difference in productivity between standard-type and spur-
type trees in 1971. In 1972, Turner Red was as productive as Sturdee-
spur and Starkrimson. Thus, in this study yields per acre in the
early fruiting years favored neither the standard nor spur-type strains
Yields from 1970 through 1978 : Cumulative yields per tree and
per acre the first 9 years showed that Turner Red was more productive
than some of the other standard- type strains. However, the producti-
vity of Red Prince, Rogers Red, Richared, Gardner Red, and Royal Red,
which are planted in orchards in eastern United States, was comparable.
The trees of the spur-type strains are smaller than those of
the standard- type strains, but production per tree of Sturdeespur,
Red Prince, Jardine Red, Richared and Rogers Red was similar. Sturdee-
spur had the highest production efficiency (production per area
occupied) of all strains.
The cumulative yields per tree indicated that Starkrimson was
the least productive of all strains, but when the theoretical yield
per acre was calculated it was not, because tlie trees of this strain
are small. The theoretical cumulative yield per acre generally was
similar for the standard-type and spur- type strains.
Water Core
Several indices have been used to estimate maturity of Delicious
strains. We chose water core because it is of annual concern and
a reliable index of maturity under our conditions. Water core is
associated with mature and over-mature Delicious fruits. Fruits with
this disorder may fail to meet U.S. Standards for Extra Fancy fruit
and severely affected apples often develop internal breakdown during
storage.
In this study, Starkrimson fruits have had less water core than
other strains. Nevertheless, the percentage of Starkrimson fruits
with water core classified as medium and severe was not consistently
less than in the other strains. Since water core can develop rapidly,
this difference in water core susceptibility may be of little practical
significance in some years.
Summary
More spur-type trees than standard- type trees can be planted
per acre because they are smaller. Allegedly, yields per acre will
be higher on spur-type trees but data to support this claim are
limited. In this study, the spur-type and standard- type strains
have been equally fruitful.
Among the standard- type strains Turner Red was more productive
per tree than Richared and Red Prince. Unfortunately under our
conditions, red color on Turner Red fruits lacked somewhat in uni-
formity.
Fruits of Royal Red, Starkrimson, Sturdeespur and Rogers Red
were rated highest for color. Gardner Red appears suitable for growers
who like bright red color rather than dark red color. Based on the
severity of water core at harvest, the fruits of Starkrimson seemed
to mature somewhat later than those of the other strains.
A**** A **************
SPUR-STRAINS OF MCINTOSH
William J. Lord
Department of Plant and Soil Sciences
Spur-strains of Mcintosh are now common in Massachusetts. The
question was asked about how they differ from their parent - Summer-
land Red Mcintosh - and from each other.
Strains common in Massachusetts are Macspur, Morspur and Stark-
spur (Gatzke strain) , all of which originated in British Columbia.
Dr. D. V. Fisher discussed the origin and characteristics of these
strains in Fruit Varieties and Horticultural Digest , Vol. 24, in 1970.
Strain B (Macspur) was discovered in a small block of Mcintosh on
seedling roots planted in 1960 or 1961 in the Mervyn Greenslade
Orchard in Summerland. Strain C [Starkspur (Gatzke strain)] occurred
as a single tree sport on a seedling rootstock planted in about 1960
in Oyama. Six apparently identical whole tree mutants occurred in
a large block in the Kelowna district. These were designated as
strain D and later named Morspur.
Lapins and Fisher in 1974 ( Can. J. Plant Sci 54:359-361) reported
that the degree of spuriness was very high in Morspur and Macspur,
high in Dewar (Strain E) , and moderate in Starkspur. However, in
our commercial orchards in New England, we are finding that the degree
of spuriness is highly variable in Macspur, with some trees exhibiting
branching and spur development characteristic of standard Mcintosh .
In 1976, W. Lane and M. Maheriuk reported on a 3-year study
[ Can. J. Plant Sci . 56:847-851) in which they compared the fruit
characteristics o£ Dewar, Macspur, and Morspur with those of Summer-
land Red Mcintosh. They found no differences in stem-associated
defects (short, long, fleshy) except that flat stem cavities occurred
more frequently on the fruits of spur strains in 2 of the 3 years.
Measurements of fruit length and diameter showed that the fruits of
the spur strains were as uniform in shape as those of Summerland Red,
but they tended to be longer and larger. Also in some instances, the
fruits of the spur strains were softer and had less soluble solids
(sugar content), probably because they were larger. In general, the
study showed that the fruits of the spur strains differed slightly
from those of Summerland Red and that the differences among the 4
strains were less than the variations in strains from year to year.
A*********
VARIABILITY IN MACSPUR STRAIN OF MCINTOSH
J. W. Swales
Horticulturist, Research Station
Summerland, British Columbia
In 1967 Horticulturists became aware of a spur-type sport of
Mcintosh in the Mervyn Greenslade orchard at Summerland, B.C.
That sport, a whole tree, received a great deal of publicity as it
appeared to be the first spur-type Mcintosh which produced commer-
cially-acceptable fruit and which possessed desirable growth char-
acteristics .
Propagating rights for this sport, named Macspur, were obtained
by Hilltop Orchards and Nurseries of Michigan. The British Columbia
Fruit Growers Association obtained propagating rights on behalf of
the tree-fruit industry and nurseries of British Columbia.
Since the discovery of Macspur numerous other spur-type sports
have been found in various B.C. orchards. Propagating rights for
those which appeared most promising were picked up by nurseries.
Consequently, today there are several spur-type Mcintosh strains being
propagated in North America.
Macspur is the spur-type strain of Mcintosh that has been most
extensively planted in B.C. during the 1970's as it is the strain
selected by the B.C.F.G.A. and propagated in their budwood orchard
for distribution to B.C. orchardists and nursery operators.
In a few of the earlier plantings of Macspur it was noted that
the occasional tree would lack spur-type characteristics. For some
time it was thought that mixing of spur-type and standard Mcintosh
trees had occurred. However, during the past 2 years it has been
observed that the incidence of standard Mcintosh trees in plantings
of Macspur has increased significantly; in one extreme case over
25% of the trees in a Macspur planting exhibit the type of growth
that is characteristic of standard Mcintosh. On the other hand, there
are many blocks of Macspur where the trees exhibit a high degree of
uniformity.
What is the cause of the problem with lack of uniformity in
some plantings of Macspur in British Columbia? Is it due to bud
selection? Is it due to a mixing of standard and spur-type trees?
Is it due to bud mutation? To date no one has come up with the
answer. It may take several years before an answer can be found.
However, it can be stated that it is thought that the variability
exhibited by Macspur in B.C. is related to bud selection rather
than reversion since the problem has been limited to whole trees,
not individual limbs.
1979 DISEASE RESULTS FOR THE MASSACHUSETTS
APPLE PEST MANAGEMENT PROGRAM
T. R. Bardinelli, C. W. McCarthy, and W. J. Manning
1
The 1979 growing season marked the completion of the first full
year of operation of the disease component of the Massachusetts
Apple Pest Management Program. The objectives of this part of the
program include using and developing predictive tools to time fungi
cide applications to achieve more effective management of apple
diseases .
Seven growers participated in the 1979 disease management pro-
gram. Disease management blocks (10 acres) and control blocks were
established in each orchard. This allowed direct comparison of
results from control and disease management blocks located in the
same orchards.
Apple scab is the ma
was focused on it. Seve
apple scab. The best kn
periods for primary appl
length of wetting period
during the wetting perio
whether or not an infect
thermograph was modified
orchard temperatures. U
devised that was used by
decide whether an infect
an eradicant kickback sp
jor disease to be managed and most attention
ral predictive tools are available to manage
own is the Mill's Table (Table 1). Infection
e scab can be determined by measuring the
s and relating it to average temperatures
ds . The table can then be used to determine
ion period has occurred, A recording hygro-
to continuously monitor leaf wetness and
sing this information, a predictive table was
participating growers to allow them to
ion period had occurred and whether to apply
ray.
Extension Technician, Scout, and Associate Professor, Department
of Plant Pathology, University of Massachusetts at Amherst.
-7-
Table 1. Approximate hours of wetting necessary for primary apple
scab infection at various temperatures.
Average temperature °F
Number of hours of wetting
78
77
76
60-75
57-59
54-56
51-53
48-50
47
45-46
44
43
42
33-41
12
11
10
9
10
11
12
14
17
19
22
25
28
48
From: Mills, W. D. 1944. Efficient use of sulfur dusts and sprays
during rain to control apple scab. Cornell Ext . Bui . No. 630.
Long periods of rain in the early primary scab season made kick-
back spraying difficult in most cooperating orchards. In spite of
this, good scab and other disease control was achieved. Results for
the seven orchards are given in Table 2 below.
Table 2. Comparison of results from disease management and control
blocks of seven orchards in the Massachusetts Apple Pest Manage-
ment Program, 1979.
Criteria
Disease management
Control
Average number
fungicide sprays
Average dosage
equivalent^
Average % disease
on fruit at harvest
Average fungicide
cost/acre
10.6
9.8
0.99
$108.64
13.0
11.1
0.93
$130.93
' . , ^ amount of fungicide used
Dosage equivalent = average recommended rate of fungicide
■8-
The average number o£ fungicide sprays in the disease manage-
ment blocks was reduced by 2.4 or 181. Average dosage equivalents
were reduced by 1.3. Fruit disease incidence at harvest, however,
was the same under both conditions. Average fungicide cost/acre
was reduced by $22.29/acre or 17%. When individual orchard pro-
files are examined, several of the participating orchards achieved
even greater reductions in fungicide applications and costs.
Four other orchards have been used to evaluate the effects of
spraying only every other row on disease incidence. The same fungi-
cide concentrations were used as in an every row program, but applied
only to every other row, alternating the rows that were sprayed.
Table 3 compares these results to those obtained in blocks where every
row was sprayed. By cutting all factors in half, a slight reduction
in average fruit disease incidence was also obtained.
Table 3. Comparison of results from four orchards using alternate
row and every row spray blocks.
Criteria
Alternate
Every
Average number
fungicide sprays
11.8
11.8
Average dosage
equivalent
5.8
11.6
Average % disease
on fruit at harvest
Average fungicide
cost/acre
0.23
$70.69
0.38
$141.38
7
„ . -, ^ amount of fungicide used
Dosage equivalent = ^— t — j r -r—r ^ ^ - i^
^ ^ average recommended rate or fungicide
The results from our first year's program are encouraging. They
are, however, only preliminary results. We need to obtain additional
results over several years of varying climatic conditions. We also
need to further evaluate and develop additional predictive tools for
disease management for apple scab and other apple diseases.
**********
INTEGRATED MANAGEMENT OF APPLE PESTS IN MASSACHUSETTS
COMMERCIAL ORCHARDS- - 1979 RESULTS: INSECTS AND MITES
W. M. Coli, R. J. Prokopy and R. Hislop
Department of Entomology
The 1979 growing season was the second year of operation of
the Massachusetts IPM program"^. The major objectives of the Massa-
chusetts IPM program are: 1) to produce high yields of top quality
apples while decreasing the amount of pesticide usage; and 2) to
encourage the use of spray materials which allow for survival of
beneficial predators and parasites.
Reduced spray programs on apples have been discussed in pre-
vious issues of "Fruit Notes [41(1), 41(2), 41(3), 42(3), and 43(3)].
Our 1978 results on insects were summarized in Fruit Notes 44(1).
Information reported here resulted from intensive scouting of
25 blocks in 20 commercial orchards in the 4 major fruit-growing
areas of Massachusetts. Scouting in the 16 IPM blocks was on a
weekly basis Avhile the 9 check blocks were visited bi-weekly because
of gasoline scarcity. In-depth orchard scouting is the keystone of
the IPM program and enables us to advise growers as to the need
and optimal timing of spray applications.
Materials and Methods
Prior to bud break in the spring, 6 to 12 trapping stations
were established in each orchard (4-11 stations per block) taking
into account size of block, proximity to likely insect overwinter-
ing sites and varietal composition. The majority of trapping sites
were near the block periphery inasmuch as most pest pressure ori-
ginates from outside the orchard. Visual traps were used to monitor
tarnished plant bug (TPB) , European apple sawfly (EAS) and apple
maggot fly (AMF) adults. Pheromone traps were used for monitoring
red-banded leafroller (RBLR) , oblique-banded leafroller (OBLR) , and
codling moth (CM) males. Mites and mite predators were monitored
from mid-June to harvest using techniques outlined in Fruit Notes
43(4). Tentiform leafminer (TLM) , green fruitworm (GFW) , green
apple aphid (GAA) , woolly apple aphid (WAA) and white apple leafhopper
(WAL) populations were monitored by examining 10 fruit spurs or 10
terminal shoots in each of 3 tree areas-- (top, low inside and low
outside) at each trapping station. (A discussion of decision making
1
Other program field staff for 1979 were: Norman Andersen, scout;
Glenn Morin, scout; Annemarie Pennucci, scout; and Mary Tubbs, scout
Mite brushing and counting were by Bonnie Weeks.
2
Funded by a USDA grant from 1978 through 1982. In addition, the
Massachusetts Fruit Growers Association contributed $5,600. Addi-
tional thanks to Mr. David Chandler, Meadowbrook Orchards, Inc.,
Sterling Junction for allowing us to base 2 scouts at his picker's
housing throughout the summer. As a result it was possible to re-
duce travel time and gasoline use.
■10-
processes based on levels of pest populations as determined by the
above techniques will be forthcoming in a future issue of Fruit
Notes . )
Fruit injury at harvest was determined in each IPM and check
block on the basis of on-tree surveys of 800-2200 fruit per block
(100 fruit per tree from each of 2 trees adjacent to trapping
stations). In addition, we sampled at harvest fruit injury from
another block in each IPM orchard of similar tree size and varietal
composition. Injury in these blocks was determined by on-tree sur-
veys of 1000 fruit per block (100 fruit per tree from trees randomly
located within the block) .
Results
Fruit Injury . Injury at harvest was divided into 2 categories:
(a) permanent damage to the skin or flesh of the fruit; and (b)
damage to the skin which could be removed by washing (i.e., woolly
apple aphids (WAA) in the stem cavity, sooty mold (SM) , or white
apple leafhopper (WAL) excrement) .
Overall, permanent damage was 6% less in IPM blocks than in
same orchard non-IPM blocks, and 23°o less than in check blocks
(Table 1). Removable injury was 95% less in IPM blocks than in
same orchard non-IPM and 93% less than in check blocks.
Specifically, as in 1978, TPB was the most damaging fruit pest
in Massachusetts commercial apple orchards, with IPM blocks averag-
ing slightly less injury than check or same orchard non-IPM blocks.
We believe that this reduction in TPB fruit injury in IPM blocks was
due to better timing of spray applications rather than differences
in pest pressure, since trap captures of TPB were nearly identical
(13.3 per trap in IPM blocks vs. 13.6 per trap in check blocks).
We attempted to develop a TPB damage grading index so as to determine
how much of this TPB injury would result in down-grading of fruit
value. Preliminary indications are that 321 of TPB injury would
grade through as U.S. Fancy fruit, 52% would grade U.S. #1 and 16%
would be culled. We plan to continue this work in 1980.
Fruit injury as well as trap captures of EAS were down substan-
tially from 1978, with virtually no difference between IPM and check
blocks. Plum curculio (PC) injury was about the same as in 1978.
Injury from PC was higher in IPM than check blocks due mainly to
substantial injury (1.6%) in one orchard. San Jose Scale injury to
fruit was considerably less in IPM than check blocks, where, as in
1978, scale was the second most damaging pest. Apple maggot fly
(AMF) captures were down substantially from 1978, perhaps due to
interference of dry weather with fly emergence from pupae. Trap
captures were slightly higher in check blocks, as was injury at
harvest from this pest. First captures of AMF in an abandoned or-
chard in Northboro, MA occurred the week of June 1, while first
captures in a commercial orchard occurred July 12. This difference
-11-
points out the need to monitor AMF directly in commercial orchards
rather than relying on abandoned orchard captures (as recommended
in Canada) to indicate the need to spray.
Table 1. Average percent of insect injury on fruit at harvest in
IPM and check commercial orchards in Massachusetts, 1979
? injury
Insect
16 IPM
blocks
11 Same orchard 9 Check
non IPM blocks blocks
Tarnished plant bug 2.74
Plum curculio 0.39
San Jose scale 0.33
Apple maggot fly 0.12
European apple sawfly 0.03
Green fruitworm 0.02
Leafrollers 0.01
Codling moth 0.00
Total I of insect injury 3. 64
Average number insecticide
applications^ 6.0
3.
,27
0.
,16
0.
,25
0.
,09
0.
,03
0.
,04
0.
,01
0.
,02
3.88
9.1
3.10
0.17
1.07
0.23
0.04
0.07
0.04
0.01
4TT3"
11.0
Woolly apple aphids 0.08
White apple leafhopper 0.01
Sooty mold 0. 00
Total I of insect injury 0.09
Average number aphicide
applications 0.36
0.71
0.08
0.27
1.18
0.67
0.05
1.56
0. 36
1.31
0.36
GRAND TOTAL % INSECT INJURY
3.73
5.44
6.04
Does not include materials directed solely at aphids (e.g., endo-
sulfan, phosphamidon) .
Codling moth (CM), leafrollers (LR) and green fruitworms (GFW)
were relatively unimportant pests in 1979, although injury from these
insects was slightly higher in check than IPM blocks. Woolly apple
aphid (WAA) injury (i.e., WAA and/or sooty mold growth on the aphid
honeydew on fruit) was identical in IPM and check blocks. Speckling
of fruit with white apple leafhopper (WAL) excrement was particularly
high in 1 check orchard, resulting in high average injury from this
insect compared to IPM blocks.
Mite Populat
(ERM) peak a
(TSM) did no
mites (ARM)
bers in IPM
unless in ex
source for o
and TSM prey
of chemicals
peak number
ions. Overall, I
nd average number
t exceed very low
were found in sub
blocks (Table 2).
cess of 300 per 1
ur major mite pre
are few in numbe
toxic to AF prob
of AF in IPM than
-12-
PM blocks had lower European red mite
s than the check. Two-spotted mites
levels in any block, while apple rust
stantial (but well below damaging)num-
ARM cause no damage to fruit trees
eaf and may serve as an alternate food
dator Ambylseius fallacis (AF) when ERM
r. Higher ARM populations and avoidance
ably account for higher average and
check blocks.
Table 2. Average and peak number of mites per leaf (IPM and check
orchards) in relation to acaricide sprays, 1979.
Acaricide
dosage
Number of mites per leaf
European Two -spotted Apple Amblyseius
Orchard No . Avg . no . equivalents^ red mites mites rust mites fallacis
type Blocks spray dates Oil Other Avg! Peak Avg. Peak Avg. Peak Avg. Peak
IPM
Check
15'
9
0.6
1.1
1.06 0.4 1.2 4.0 0.3 0.8 34.5 69.3 0.03 0.11
1.04 1.7 2.3 10.0 0.3 0.6 8.3 19.1 trace 0.01
block not included (grower did not comply with IPM recommendations)
One
^p. • -1 „^ _ actual pesticide rate/100 gal.
" ^ NY recommended pesticide rate/100 gal.
In keeping with program objectives, IPM growers have generally
avoided the use of materials which are known to be harmful to bene-
ficial predators and parasites [ Fruit Notes 43(5)] . The recent ad-
vent of spotted tentiform leafminer (STEM) as a major pest
chusetts and use of the carbamate insecticide, Lannate*,
STEM posed a serious threat to IPM objectives.
in Massa-
to control
In one Granville area orchard this season, high counts of second
generation STEM mines indicated a need to treat for this pest using
Lannate*. For the remainder of the season there was a sharp decline
in numbers of Amblyseius fallacis (AF) . The possibility exists that
AF may survive in the ground cover if spray runoff is not excessive,
although this remains to be proven.
Trade name
-13-
Insecticide, aphicide and miticide use . IPM blocks received 46^
fewer insecticide sprays (average 6.0, range 4-7) than the checks
(average 11.0, range 6-12) (Table 1). Same orchard non-IPM blocks
received an average of 9.1 sprays, suggesting that growers applied
some information from IPM block scouting to the rest of their or-
chard. The average numbers of aphicide sprays was identical in
IPM, check, and same orchard non-IPM blocks (Table 1). Fewer
miticide sprays (e.g., Plictran* and/or Omite*) were applied to
IPM blocks (average 0.6) compared to checks (average 1.1) [Table
2] or same orchard non-IPM (average 1.0) [date not shown].
In contrast, use of oil as an ovicide was about equal in
IPM and check blocks.
In addition to the substantial reduction in spray application
dates, there was also a reduction in dosage equivalents for insecti-
cides (42% reduction), aphicides (60'o reduction) and miticides
(76% reduction) in IPM compared to check (Table 3) .
Cost and benefit comparison . Table 3 summarizes the cost benefit
analysis of IPM vs. check blocks. Average costs per acre for
insecticide and miticide materials, respectively, were $51.64 and
$14.59 lower in IPM blocks, while aphicide costs were nearly
identical with the checks. IPM spray material application costs
were also lower due to the reduction in number of spray dates. At
harvest, IPM blocks had 23% less fruit injury due to insects,
resulting in an average of $40.46 less fruit loss per acre than
check blocks. As a consequence, compared with check growers, IPM
growers realized an average net benefit of $122.83 per acre from
the IPM program. This finding, coupled with a $71.00 net benefit
from the IPM program in 1978, indicates the potential economic
value to Massachusetts fruit growers of implementation of an IPM
program on apples.
Trade Name
-14-
Table 3. Cost benefit analysis of insect and mite results in 16 IPM
and 9 check commercial apple blocks in Massachusetts, 1979.
Observation
Orchard:
IPM
check
Difference IPM
vs . check :
Difference (I)
Average number
spray dates
per acre
Average number
dosage equivalents for'^
Insecticides
Aphicides
Miticides
Average cost/acre
spray materials for:
Insecticides
Aphicides
Miticides
Spray applications^
Average % of
insect injur/
Average value per
acre of fruit loss
due to insect injury
Average net benefit
per acre from IPM
w
6.0
3.64
$90.01
11.0
4.73
$130.47
■5.0
- 1.09
-$40.46
+$122.83
(46)
5.8
10.1
-4.3
(42)
0.2
0.6
-0.4
(60)
0.4
1.7
-1.3
(76)
$53.99
$105.62
-$51.64
$ 3.46
$ 3.35
+$ 0.11
$11.25
$ 25.84
-$14.59
$19.50
$ 35.75
-$16.25
(23)
p. ■ -. . actual pesticide rate/100 gal.
Dosage equivalent = ^^ ^ t— 3 " . . , g^ ,, „„ t-
* ^ NY recommended pesticide rate/100 gal.
r
Based on 15 min. time to spray 1 acre, $5.00/hour labor cost and $2.00/acre/
application for fuel and oil.
Does not include injury from sooty mold, white apple leafhopper and woolly apple
aphids which could be removed by washing fruit.
Based on average values as of Sept. 30: U.S. Fancy fruit @ $10.50/bu., U.S. #1
fruit @ $7.00/bu., Cull fruit @ $2.00/bu. and average yields of 550 bu./acre.
w
**********
15-
FRUIT NOTES INDEX FOR 1979
(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. 44 (No.l)
Varieties of Strawberries for Massachusetts (1-3)
Pruning MacSpurs (3)
Pomological Paragraph - Stub pruning (4)
Pruning Peach trees (4-6)
Control of Water Sprouts and Suckers with Tree-Hold* (6-8)
U.S. Apple Exporters Expect Another Good Year Following
Record Showing in 1977/78 (8-11)
Integrated Management of Apple Pests in Massachusetts - 1978
Results: Insects (12-16)
March/April Vol. 44 (No. 2)
Monitoring Apple Maggot Flies, Sawflies, and Plant Bugs with
Visual Traps (1-5)
Rootstock Testing on an International Basis (6)
Treatment of Girdled Fruit Trees (7-9)
Nutritional Problems in 1978 and Suggestions for Fertilization
of Apple Trees in 1979 (10-12)
Pomological Paragraph - Deeper planting may reduce suckering from
the rootstock on interstem trees. (12)
Apple Disease Incidence in Massachusetts in 1978 (13-15)
May/ June Vol. 44 (No. 3)
Influence of Training on Growth of Newly-planted trees (1-3)
Promalin Studies in 1978 and Comments on Trial Use in 1979 (4-8)
Harvesting Early Ripening Apple Cultivars (8)
Chemical Thinning of Apples in 1979 (9-11)
Growth Regulator Spray for Growth Suppression on Apple Trees (11)
Suggestions for Use of Chemical Thinners on Several Apple
Varieties (chart) (12)
Alternate vs. Every Middle Spraying for Apple Pests in 1978 (13-15)
July/August Vol. 44 (No. 4)
Brown-Line Decline of Apples (1-2)
Poor Apple Growth Disease in Massachusetts (3)
Coating the Trunks of Fruit Trees to Reduce Winter Injury (4)
Photographs of Nutrient Deficiences (5-6)
Further Observations of Tree Performance on M26 (6-8)
Use of Ethephon to Promote Color and Ripening of Apples in
Massachusetts (9-11)
Pomological Paragraph - Foliar sprays (11)
-16
September/October Vol. 44 (No. 5)
A Preliminary Evaluation of Labor Productivity in Grading
and Packing Mcintosh Apples Grown under Integrated Pest
Management Conditions (1-6)
Toxicity of Orchard Pesticides to the Mite Predator Amblyseius
fallacis 1979 Results (6-8)
Propagating Your Own Fruit Trees (9-11)
Some Problems That Can Reduce Storageability of Apples (11-13)
Pomological Paragraph - (Benlate tolerant storage decays) (14)
November/December Vol. 44 (No. 6)
Carbon Monoxide Accumulation in CA Storages (1)
Evaluation of Delicious Strains (2-4)
Spur-Strains of Mcintosh (4-5)
Variability in Macspur Strain of Mcintosh (5-6)
1979 Disease Results For The Massachusetts Apple Pest Manage-
ment Program (6-8)
Integrated Management of Apple Pests In Massachusetts Commer-
cial Orchards--1979 Results: Insects and Mites (9-14)
Fruit Notes Index for 1979 (15-16)
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
(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. 45, No. 1
JANUARY/FEBRUARY 1980
TABLE OF CONTENTS
Further Trials with Naphthalene Acetic Acid (NAA)
for Tree Training
Winter Injury to Fruit Trees in 1978-79
Winter Injury in New Hampshire - A Grower Survey
Progress Report: Height Containment on Spartan and
I da red Trees
Alternate vs. Every Middle Spraying for Apple
Pests in 1979
FURTHER TRIALS WITH NAPHTHALENE ACETIC ACID
(NAA) FOR TREE TRAINING
William J. Lord and Duane Greene
Department of Plant and Soil Sciences
It was reported in 1977 that 11 NAA in latex paint is an ex-
cellent tree training aid when applied as a painted band around
the stem o£ newly-planted apple trees (after heading) to cover the
second, third, and fourth buds. The first bud below the heading
cut, which was not painted, became a vigorous central leader. This
treatment eliminated the cluster of vigorous shoots in the top of
the trees which compete with the central leader and increase the
number of favorably positioned branches on the newly-planted trees,
and improve crotch angles of these branches. If for some reason
the bud selected for the central leader died, a strong leader report-
edly developed from the NAA-treated area. Basically, the suggested
NAA treatment is a replacement for the current training procedures
which involve removal by hand, in June, of growth that is in com-
petition with the shoot favored as a central leader.
Directions for use indicated that the 1% NAA in latex paint
should be applied after heading the newly-planted tiee to the desired
height but before growth begins. The treatment is not effective if
made after start of growth.
We tried the NAA-tree training technique on Marshall Mcintosh,
Macoun, and Redspur Delicious in 1977. In the May/June, 1978 issue
of Fruit N otes we reported that the treatment was a complete disaster.
The f irs t ~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.
Further tests were conducted in 1978 on 1-year-old Redspur Deli-
cious trees after heading, using concentrations of 0.25%, 0.50%, or
1 . 0% NAA in latex paint. Applications of 0.50% or 1.0% suppressed
leader growth, although the reduction was less than recorded in 1977.
Leaders on trees painted with 0.25% NAA in latex were shorter than
those on the headed control, deshooted, or disbudded trees when mea-
sured on August 8, 1978 but not on September 9, 1978. Thus, it appears
that trees may overcome the inhibitory effects of NAA if concentrations
applied are not excessive.
Thus, we concluded from our 1977 and 1978 trials that NAA, ethyl-
esr.er at 0.5 to 1.0% in latex may suppress leader growth when applied
as a band on newly planted or 1-year-old apple trees after heading.
Furthermore, it has at least 4 obvious drawbacks. Spring is an
ex',, erely busy season and chances are good that the NAA will not be
-2-
applied. Secondly, the treatment must be applied before growth
starts. Thirdly, the present procedures of leader selection are
less time consuming than the NAA treatment. And lastly, a better
choice of a leader often can be made in mid-June and this job can
be combined with limb spreading with clothespins. Thus, we will
continue to suggest the present procedures of leader selection.
This involves selection of the uppermost shoot on the windward side
of a 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 distance of approximately 6 inches down the stem.
AAA*******
WINTER INJURY TO FRUIT TREES Ifl 1978-79
William J. Lord and Peter Veneman*
Department of Plant and Soil Sciences
Pomologists in the early 1900's considered winter injury to
roots of fruit plants to be a major problem of fruit production
in northern growing areas. Thus, considerable time was devoted to
the study of low temperature effects on tree roots. However, a
search of literature shows that root-kill on fruit trees has occur-
red only once during this century in Massachusetts prior to this
past winter.
G.E. Stone, Botanist for the Massachusetts Agricultural Experi-
ment Station, stated that root injury to apple trees occurred dur-
ing the severe winter of 1903-04. No mention was made of temper-
atures and snow cover in orchards that sustained injury. Minimum
temperatures at Amherst in December, 1903 and January, 1904 were
-3.5° F. and -26° F., respectively. The mean temperature for Janu-
ary was only 14.3° F. A total of 36 inches of snow fell at Amherst
in December, 1903 and January, 1904.
Whether or not the snow cover was lost in the orchards where
winter injury occurred is not known. During the winter of 1898-99
winter injury was widespread in Wisconsin, Iowa, Minnesota, and
Canada. It was observed that where there was good snow cover there
was no root injury when air temperature went as low as -50° F.
The winter of 1933-34 was also unusually severe but the injury
was confined to the above-ground tree portions. February was espec-
ially cold with a minimum temperature of -22° F. and a mean tempera-
ture of only 11.6° F. for the month at Amherst, MA. The 3 major types
A
Assistant Professor of Soil Sciences
-3-
of winter injury that occurred during the winter of 1933-34 were:
killing of the sapwood in the branches and trunks; loosening and
splitting of bark on the trunk; and injury to flower buds and spurs.
Winter injury to above-ground portions of fruit trees has also
occurred since the writer came to Massachusetts in 1955. In the
spring of 1956 we found severe winter injury to the trunks and lower
scaffold limbs of bearing trees, mainly Mcintosh in several orchards.
The bark on the injured tree trunk was split and usually pulled
away from the wood. The injury was most predominant on the south
side of the tree, but no side was immune. The winter injury appeared
to be associated with pruning during late December and early Janu-
ary. During the winter of 1956-57 extensive wood injury and injury
to both flower and leaf buds occurred on peach trees and to flower
buds on sweet cherries and plums.
Pruning-related injury also occurred during the winter of 1975-
76. It was found in more orchards than in 1956 and also occurred
in Connecticut and New Hampshire. The trunk injury was associated
with pruning done as late as the 3rd week of January in 1976 in
some orchards. Cold injury and how it relates to the winter injury
in 1975-76 was reviewed by D.A. Kollas in 1978 in Fruit Notes 43(6):
1-5.
This past winter (1978-79) root-kill was the predominant type
of injury to apple and peach trees. On peach trees the bark on the
trunk at ground level or below ground also was injured.
The main objective of this article is to have a written account
of winter injury in 1978-79 for reference if similar damage occurs
in the future.
Early Studies on Root Damage
Roots have been found to be the tenderest part of the apple
tree although those that have been exposed throughout the previous
growing season have cold tolerance equal to the above ground tree
parts. D.B. Carrick in New York State (Cornell University Agr. Exp.
Sta. Memoir No. 36, 1920) reported that, under laboratory conditions,
apple roots frozen in October and November were more tender than
those frozen in February or early March. The period of maximum re-
sistance to freeze damage seemed to end before last of March. J.R.
Magness in Washington State showed that bark of apple roots was
killed at temperatures as high as 23° F. in November. ^Root samples
taken in early December were killed by exposure to 17° F.
G.F. Potter in New Hampshire reported that 16° F. was usually
critical for roots of 1-year-old apple trees under laboratory con-
ditions. Very rapid freezing of roots to 18° F (in a half hour or
less) caused more injury than when freezing them so that the roots
reached the same temperature after 6 or 7 hours. However, rate of
thawing did not affect the severity of the low temperature injury.
-4-
In studies with peach trees, D.B. Carrick stated that it
is not easy to assign an arbitrary limit within which the roots are
injured by freezing. "This is because of the great variation in the
root tissues. The peach cambium certainly is as hardy as the pear
cambium though less so than the apple. Regardless the size of root,
most of the peach material tested showed some injury at -10° C.
(14° F.) , and except in unusual cases, serious injury occurred at
-11° C. (12° F.)".
Winter Weather, 1978-79
Temperatures in December, 1978 in Central Massachusetts (where
most orchards are located) averaged 0.8° F. higher than normal, and
the maximum snow depth varied from 4 to 11 inches depending on loca-
tion of the weather station. Temperatures in January continued to
be somewhat higher than normal and maximum snow cover varied from 3
to 11 inches. At the Horticultural Research Center (FiRC) in Belcher-
town, there were 4 snow storms in January: 2 inches on the 5th and
13th, and 3 inches on the 17th and 20th. However over 8 inches of
rain fell after these storms and eliminated the snow cover: 2.3
inches on the 7th and 8th, 1.1 inches on the 13th, 2.5 inches on
the 20th and 21st, and 2.5 inches on the 24th and 25th.
Temperatures in Central Massachusetts were 8.6° P. lower than
normal in February, snow fall averaged 6 inches, and the maximum
depth of snow on the ground varied from 3 to 10 inches, depending
on the location of the weather station. There was one snowstorm of
2.5 inches in February at the HRC prior to -10 to -14° F. tempera-
tures from the 9th through the 17th. Although the air temperatures
were not extremely low, soil temperatures at 8 and 30 inch depths
in one block of trees in sod were 19° F. and 30° F. , respectively,
on February 16th.
Symptoms of Injury
Apple . The first symptoms of injury to apple trees at the HRC
was observed on May 7 at the full pink stage of blossom development.
Blossoms on 1 limb, 2 or 3 limbs, or the entire tree were white in
color rather than pink and leaf margins were brown. Maximum air
temperatures of 84° F. , 93° F. , and 91° F. were recorded on May 8th,
9th and 10th, respectively. The symptoms worsened considerably dur-
ing this time, with more trees exhibiting injury, and the blossoms on
the affected branches failed to open and eventually wilted and aborted,
Examination of the roots revealed that the wood was brown which in-
dicated winter injury had occurred.
Severely affected trees died as the growing season progressed.
Other trees began to exhibit light-colored foliage, with interveinal
mottling that was orange in color. These trees made little terminal
growth and had a light crop. It is possible that many of the severely-
weakened trees will have to be replaced in 1980. Injury symptoms did
not worsen on trees having only 1 or 2 affected branches. It also
was of interest to note that latent buds produced growth on some of
these affected branches.
Peach . The injured trees bloomed and then the blossoms wilted.
By late-May or early June, thousands of these trees had died or ex-
hibited severe injury. In some orchards entire blocks of trees were
removed in June. Weakened trees that were not removed had sparse
foliage throughout the summer and few peaches. These trees should
be replaced in 1980.
Injury In Other Areas
Winter injury in New Hampshire is discussed in separate article
in this issue of Fruit Notes . It also occurred in Washington, New
York, Maine and probably in other areas.
According to James Ballard, Yakima County Extension Agent, Cen-
tral Washington, fruit orchards and vineyards suffered severe dam-
age in January, 1979. Sub-zero weather occurred during the last
week of December, 1978, and temperatures remained below freezing
for 24 consecutive days. Snow cover did not come until January 11,
1979, and by then the cold had penetrated root zones and soil temper-
atures had dropped to 14° F. The damage was most severe on trees
5-years-old or younger, planted on rocky, cultivated ground that
had little or now snow cover.
Richard Norton, Fruit Specialist in Rochester, NY stated in
Spray Letter No. 10, May 13, 1979 that winter injury was the major
cause of: "(1) dying cherry trees - most young non-bearing trees;
(2) dying lower branches in bearing apple trees, particularly un-
pruned or poorly pruned trees, (3) spur dieback of young apple
In July, 1979 Herbert Wave and Warren Stiles reported symptoms
of winter injury in Maine. They stated that the injury was varied
with malformed and/or russetted fruit, dieback of limbs and/or tops
of young trees, or killing of the rootstock. Most root injury occur-
red on wet soils or where there was little or no snow cover during
mid-winter.
Cause and Factors Influencing Injury
We believe the injury to the peach trees in Massachusetts,
which are generally planted on well-drained slopes, was due to lack
of .snow cover which allowed deep penetration of frost and alternate
thawing and freezing of the roots. At the HRC, the older bearing
peach trees which had large crops in 1978 were injured more severely
than younger trees commencing to bear.
Paraquat had been applied annually to control grass and broad-
leaf weeds under all peach trees at the HRC but they also had re-
ceived periodic applications o£ hay mulch, which was last applied
in 1977. Thus, mulch did not prevent damage.
Frequently roots of fruit trees appear more susceptible to
winter injury in dry than in wet soils. However, at the HRC, the
injury to apple trees was worse on heavy, poorly-drained soil.
Thus, the combination of poor soil aeration, 8 inches of rain in
January and no snow cover intensified the problem of root injury.
Nevertheless, trees were injured on well-drained soils both at the
HRC and commercial orchards or where ledge prevented deep rooting.
It was not possible to determine whether rootstocks differed
in susceptibility. An interplanted block of mature trees on seed-
ling roots and M.7 was equally damaged in a commercial orchard. In
other blocks in the same orchard, "filler" trees on MM106 died where-
as the injury to those on M.7, MMlll, or M.2 rated from none to
medium. At the HRC soil rather than rootstocks appeared to be the
more important factor contributing to winter injury. No Miller-
spur or Empire trees with an 8-inch interstem of M.9 on Antonovka,
Mlvllll or Ottawa 11 planted in 1976 on well-drained soil were injured
even though soil temperature at 8-inch soil depth went to 19° F.
However, Mcintosh and Delicious on MM106, M.7 or M.26 planted the
same year in the same block, were severely injured where the soil
is poorly drained due to a hardpan underneath. In other blocks on
MM. 106, M.7 or M.26, the injury to roots was clearly associated with
areas having poorly drained soil.
Summary
Growers have become concerned because of the winter injury to
roots, especially in the absence of sod under their trees because of
annual use of a contact herbicide such as paraquat plus a soil steri-
lant (diuron or simazine) . Studies have shown that soil temperatures
in winter can be higher under a sod or sod-plus-mulch than under bare
sod. However our peach trees at the HRC were severely injured last
winter in spite of a heavy residue of mulch. We are more concerned
about the occurrence of soil erosion and tree heaving on bare soil,
which is much more common, than possible v\rinter injury to roots.
This last summer, we tagged individual limbs and whole trees
at the HRC after rating the severity of winter injury. This should
enable us to determine the degree of tree recovery in the orchard.
Hopefully, the combination of excessive rainfall in January
and bare soil in early February during a period of sub-zero air
temperatures, will not reoccur for many years.
WINTER INJURY IN NEW HAMPSHIRE- -A GROWER SURVEY
William G. Lord
Extension Specialist, Fruit
University of New Hampshire
Winter injury to the roots of apple trees is certainly
not a common occurrence in New Hampshire, since an adequate
snow cover usually protects tender tree roots from extreme
low temperatures. However, throughout much of southern
New Hampshire in the winter of 1978-79 snow cover was light
and bare wind-blown spots were commonplace. Added to this
were low soil moisture levels and long, uninterrupted periods
of very cold temperatures - -all the ingredients necessary for
root injury.
The symptoms of severe injury have been well detailed.
At about bloom, leaves and blossoms on the affected trees
wilt and die. On less severely affected trees, the leaves
wilt but seem to recover and injury to blossoms is less severe.
New leaves develop and although the tree sets a very light
crop and makes no growth, at least the tree is alive. Dam-
age of these 2 types is easy to assess and tree crop losses
can be accurately and easily determined. However, low level
inj ury- - injury that shows up as reduced tree growth, poor
leaf color, and reduced set and yields--is difficult to assess
and, I feel, tremendously underestimated.
This Fall a grower survey was initiated to determine the
extent of injury and to correlate the incidence of injury to
site, rootstock, variety, etc. The following conclusions can
be made based on the survey replies:
1) Rootstock had no effect on the incidence of tree
injury. Injury was reported on all the major
rootstocks in use in New Hampshire- - seedling , M-106,
M-7, M-26, and M- 9/MM- 106 interstems . Where more
than one rootstock was present in a particular block
showing injury, all rootstocks showed injury.
2) Tree cultivar likewise (and expectedly) had no
effect on the incidence of injury.
3) Affected trees ranged in age from 1-year-old semi-
dwarfs to 60+year-old standards. Again, no correla-
tion existed between age and injury.
4) Herbicide program effects on tree injury are not so
clear-cut. It would appear from the grower responses
that the majority of sites reporting injury had no
herbicide application in 1978, indicating that per-
haps there was a slightly greater incidence of injury
in blocks where no herbicides were applied. However,
it seems more probable that this simply reflects the
smaller number of growers who use herbicides rather
than any correlation to injury.
-8-
5) There appeared to be a correlation between the occur-
rence of injury and site. Most injury occurred on
wind-blown sites and on sites with a high-water table
where the trees had previously shown symptoms o£ "wet
feet".
Estimating crop loss can be difficult; however, I feel
we can approximate the actual crop loss using data supplied
to us by growers. The grower data indicate the following
crop losses.
Trees Dead Trees Severely Injured Est. Crop Loss (bu)
3800 10,615 188,965*
Adjusted to reflect lost crop as replacement trees develop.
As substantial important as these figures seem, most v/in-
ter injury went unrecorded. The injury that escaped notice
was the less severe type- -the poor tree vigor and the reduced
crop set and yield. This less severe vrinter injury probably
will cost our growers much more in the lost production than
the losses recorded above.
ft******************
PROGRESS REPORT: HEIGHT CONTAINMENT ON SPARTAN AND I DARED TREES
William J. Lord and Anthony Rossi
Department of Plant and Soil Sciences
Pyramid-shaped trees on the more dwarfing rootstocks will
produce the bulk of their crop within reach from the ground,
without a ladder, and should produce well-colored fruits through-
out the tree. However, the most heavily planted size-control-
ling rootstock in Massachusetts is Mailing 7 (M7) , on which vig-
orous cultivars will produce trees 16 feet or taller. When
asked what they consider to be the ideal height for trees on
vigorous size-control rootstocks, the answer given by growers
generally varied between 10 to 14 feet.
At present there is no rootstock more suitable than M.7
for our cultivars, with the exception of Delicious. However,
it may become necessary to lower or contain the height of trees
on M7 in the future because of the shortage of suitable harvest
labor. Therefore, questions to be answered are: (1) What is
a suitable pruning method for containing tree height? (2) What
is the influence of height reduction on yield? To answer these
questions we established a demonstration in 1976 on 12-year-old
Spartan and Idared trees on M7 planted at the Horticultural Re-
search Center at 20 ft. x 30 ft. spacing. We consider trees of
Spartan and Idared to have medium and low vigor, respectively.
Pruning and Training Procedures
The trees were not excessively tall, the Spartan and
Idared trees averaging 12 ft. and
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11 £t., respectively.
However, the leader had
lost its dominance on
some trees, particularly
on Spartan, and no attempt
had been made to maintain
pyramid-tree shape. Tree
height was restricted on
even numbered trees in a
25-tree row of Spartan and
in a similar row of Idared.
This was accomplished by cut-
ting back the leader to an
outward growing branch (Fig-
ure 1) and maintaining tree
height at this level. On
odd numbered trees in each
row we gradually shortened
the central leader so trees
of both cultivars are approx-
imately 2.5 ft. shorter than
the height-restricted trees.
Height of the leader on the
height-reduced trees averaged
8.9 ft. and 8.3 ft., respect-
ively, after pruning in Feb-
ruary, 1979. Height of the
height-restricted Spartan and
Idared trees averaged 11.4
and 10.6 ft., respectively.
Figure 1. A Spartan/M7A tree planted in 1964. The central
leader was cut to a lower horizontally growing
lateral branch. A branch rotation program has
been initiated in the top third of the tree.
A comparison of the trees is shown in Figures 2 and 3. (Tree
spacing appears much greater in the photographs than in reality ,
Trees of both cultivars are planted at 20 ft
Branch spread of the Spartan trees is 17 ft
X 30 ft. spacing.
therefore, 17 ft.
X 25 ft. spacing would be ample. Branch spread of the Idared
trees is 14 ft., thus 14 ft. x 22 ft. spacing appears suitable
for this cultivar.)
■10-
Figure 2. Spartan trees planted in 1964; picture taken March,
1979 after pruning height of the tree on right has
been gradually lowered since 1976. The height-
reduced trees now average 9 ft. in comparison to
11.4 ft. on the control trees.
On both the control and height - lowered trees some of the
stronger branches in the top third of the trees were removed
or their length restricted by cutting to a weak lateral branch.
A few water sprouts were retained and spread for replacements
of pruned vigorous branches. Thus, we have developed a branch
rotation program which consists of removing large branches in
the top third of the tree and leaving weak branches which
turn will be removed when they become largei" (Figure 1).
in
-11-
Figure 3. Idared trees planted in 1964; picture taken March,
1979 after pruning. Height of the tree on the
left has been gradually lowered since 1976. The
height-reduced trees average 8.3 ft. and the
control trees 10.6 ft.
Spreaders with nails, sharpened on an emery wheel, at
each end have proven satisfactory for positioning 1-year-old
sprouts (Figure 4) . The water sprouts positioned in 1976
became sizeable branches within 2 growing seasons (Figure 5).
Another method used to develop new lateral branches involved
leaving a short stub by making a sloping cut when a favorably
positioned lateral branch originating from the central leader
was removed.
A shoot that develops from the stub on the central leader
is retained and positioned (Figure 6) .
Figure 4. Softwood sticks
3/4 X 3/4 inch
or 1 X 1 inch
and cut to var-
ious lengths are
frequently used
for limb spread-
ers. 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. Sharpen-
ing the nails
with an emery wheel
will expedite posi-
tioning of water
sprouts and reduce
damage .
Figure 5. A limb on Spartan
in November, 1977
that was spread
when a water sprout
in February, 1976.
■13-
Figure 6
Water sprouts
that develop
from stubs can
become valuable
replacement limbs
i£ positioned.
The arrow points
to the wooden
spreader on a
water sprout on
a Spartan tree.
Observations and Results
Limb rotation in the top third of the tree, which in-
volves cutting vigorous branches back to the leader or to
a much weaker side branch which in turn will be removed when
it becomes large, may be a suitable tree containment techni-
que regardless of planting density.
Retaining and spreading water sprouts to replace pruned
branches appears practical and is being done in some commercial
orchards. Many trees require no limb spreaders and when used,
only 2 or 3 are generally necessary.
A shoot originating from a stub of a branch removed from
the central leader can become a valuable replacement limb.
Shoots originating from the lower side of the stubs generally
have the most desirable crotch angles. Therefore, when remov-
ing the branch from the central leader, we suggest a slanting
cut be made so that the top of the stub will be flush and
the bottom of the stub will project about 1 inch.
•14-
The yield reduction on the height- reduced trees was
not consistent until 1978 (Table 1). In 1978 and 1979 the
shorter trees of both cultivars produced less fruit than the
taller trees. The 2.5 foot reduction in tree height reduced
yield by 2.5 to 3 bushels in 1979. This is a sizeable re-
duction in yield and should be considered when reducing
tree height in an established planting. New plantings can
be designed with higher tree densities to compensate for
bearing surface lost by keeping trees shorter.
Table 1. Influence on yield from height reduction of
Spartan and Idared treesz.
Spartan^ Idared
X
Height Height
Year reduced Control reduced Control
Bushels/tree
1976 6.0^ 8.0a 6.2a 7.5a
1977 4.0b 5.3a 4.1a 4.8a
1978 10.4b 12.5a 10.2b 12.4a
1979 9.6b 12.9a 8.9a 11.4a
z
Trees planted in 1964; trial started in Feb., 1976.
y
Tree height 3/79: Control - 11.4'; height- reduced trees:
8.9'
X
Tree height 3/79: Control - 10.6'; height-reduced trees:
8.3'
w
Means in any row for each cultivar followed by different
letters are significantly different at odds of 19 to 1.
Summary
We plan to maintain the 2.5 foot height difference be-
tween the height-restricted and height-reduced trees in 1980
and 1981 in order to determine the yield differences. It is
unfortunate that Mcintosh trees are not in this trial because
it would be of interest to determine the effect of pruning on
fruit color. Nevertheless, this trial and others has supplied
valuable information on containment pruning, and should continue
to do so. Trees on vigorous-size controlling rootstock are the
predominant type tree in Massachusetts. We believe that by main-
taining a dominant central leader and doing containment pruning,
trees on M7, MMlll, and MM106 can be kept to a size suitable
for medium density orchards (115-200 trees per acre).
-15-
Allornate vs. Hvtry Middle Spraying For Apple Fesi ? in 1979
William M. Coli and Ronald J. Prokopy"
Department o£ Entomology
In previous issues of Fr uit Not es , we reported our 1977
and 1978 findings on the comparative effectiveness of alter-
nate-middle vs. every-middle spray treatments for apple pest
control. (See Fruit Notes 45(5) : 15-19 and 44(5): 15-35.)
The 1979 results of alternate middle spraying fox apple
diseases have been reported in the November/December, 1979
issue of Fruit N otes . Here, we present (a) our findings on
alternate middle vs. every middle spraying for apple insects;
(b) further information on diseases, and (c) a cost-benefit
comparison with regard to insects, mites and disease control.
Alternate middle spraying involves spraying alternate
halves of each tree on alternate spi;ay 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 6 and return down the middle between rows C
and D, skipping the middle between rows B and C. For the sec-
ond cover spray, the sprayer would be driven up the middle be-
tween rows B and C, down the middle between rows D and E, and
so forth. If this pattern is followed on each spray date, it
would save 50% of spray material and application costs.
Each of four test blocks in commercial orchards was divided
into 2 plots of 2-6 acres each. One plot received the alter-
nate middle program on each spray date throughout the season.
The other received tlie every middle urogram. Each grower used
an air-blast sprayer and a concentration (IX, 4X, etc.) of his
own choosing. Growers followed their normal spray schedule
and selected their own pesticide materials. Except in one
block, all trees were fully groivn, some on M7 rootstock,
others on seedling. Pruning was generally adequate to allow
for good spray penetration into tree centers.
Monitoring of Pest Populations
We utilized commercially available visual traps to moni-
tor populations of tarnished plant bugs, European apple saw-
flies, and apple maggot flies as well as pheromone traps for
1
Extension Pest Management Specialist (Entomology) and Extension
Tree Fruit Entomologist, University of Massachusetts at Amherst,
Other field personnel were Glenn Morin, Senior Scout; Norman
Anderson, Clarence Boston, Annemarie Pennucci, and Mary Tubbs,
Scouts .
-16-
codling moth, redbanded leafroller and oblique-banded leaf-
roller. Visual inspections of fruit and foliage in all por-
tions of the tree canopy were used to monitor populations
of plum curculio, spotted tentiform leafminer, green apple
aphids, and aphid predators.
Sampling was only tri-weekly, due to gasoline scarcity.
An on-tree survey of 1200 fruit per treatment block was per-
formed at harvest to determine injury levels to fruit.
Insect Injury to Fruit At Harvest
Total insect injury at harvest averaged 2.84% in alter-
nate-middle blocks vs. 3.61% in every-middle blocks (Table 1)
below.
Table 1. Average percent of insect and disease injury to fruit
in 4 alternate-middle vs. every-middle commercial orchard
blocks in Massachusetts, 1979.
Insect
Every-middle Alternate-middle
Tarnished plant bug
3.07
Plum curculio
0.27
San Jose scale
0.19
Apple maggot fly
0.04
European apple sawfly
0.02
Green fruitworm
0.02
Codling moth
0.00
Other
0.00
Total
3.61
2.48
0.12
0.04
0.02
0.02
0.02
0.00
0.14
2.84
Disease
Every-middle Alternate-middle
Scab
Rots
Rusts
Total
Total injury from insects
and disease
0.24
0.14
0. 00
0.38
3.99
.06
.11
.06
.23
3.07
In 1979, the most serious pest in both types of blocks
was tarnished plant bug, which accounted for 2.48% injury in
alternate-middle blocks vs. 3.07% in every-middle blocks.
-17-
Injury from the other major insect pests (plum curculio, San
Jose scale and apple maggot fly) was consistently greater in
every-middle than in alternate-middle blocks. European apple saw-
fly and green fruitworm injury levels were identical under both
treatments, whereas leafroller injury was high (0.58%) in one
alternate-middle block.
Disease Injury to Fruit at Harvest
Apple scab was the principal disease problem in all blocks.
Various rots were of secondary importance, while rusts were only
occasionally present (Table 1) .
Overall disease incidence was slightly greater in every-middle
(0.381) vs. alternate-middle (0.23%) blocks. (For more information
concerning 1979 disease results in alternate-middle vs. every-
middle blocks, see Fruit Notes 44(6): 6-8.)
Cost Benefit Comparison
In 1979, alternate-middle spraying resulted in a savings of
$62.61 per acre for insecticide and miticide materials and appli-
cation costs. Fungicide materials and application costs were $70.69
less in alternate-middle blocks. Fruit loss due to insect and dis-
ease injury was $19.03 and $6.70 less, respectively, in alternate-
middle blocks (Table 2).
Table 2. Cost benefit analysis of every-middle vs. alternate-
middle treatments, 1979.
Dollar cost/acre
Every- Alternate-
middle middle Differences
Avg . cost of insecticide
and miticide materials
and application $125.23 $62.62 -$62.61
Avg. value of fruit loss
due to insect injury $ 78.93 $59.90 -$19.03
Avg. net benefit from alternate-middle
spraying for insects and mites +$81.64
Avg. cost of fungicide
materials and application $141.38 $70.69 -$70.69
Avg. value of fruit loss
due to disease injury $ 17.80 $11.10 -$ 6.70
Avg. net benefit from alternate-middle
snraving for diseases +$77.69
Ave. net benefit from alternate-middle
spraying for insects, mites and diseases +$159.33
Growers utilizing alternate-middle spraying realized
a net benefit of $81.64 per acre with regards to insects and
mites, and $77.69 for diseases, or a total average net bene-
fit of $159.33 per acre.
We believe that our 1979 results, as well as those from 1978,
indicate the potential usefulness of alternate-middle spray-
ing, perhaps most advantageously employed when in combination
with intensive IPM weekly scouting and grower advisement. (See
Fruit Notes 44(6) : 6-8, 9-14.)
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
(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. 45, No. 2
MARCH/APRIL 1980
TABLE OF CONTENTS
Airblast Sprayers for Orchard Spraying
Spotted Tentiform Leafminers:
Biology, Monitoring, and Control
More About Nematodes and Fruit Trees
AIRBLAST SPRAYERS FOR ORCHARD SPRAYING-*"
Kenneth D. Hickey
Pennsylvania State University Fruit Research Laboratory
Biglerville, PA 17307
Airblast orchard sprayers which form, transport, and deposit
water droplets onto all above ground parts o£ trees are essential
to the commercial production of deciduous fruit crops in eastern
fruit growing areas. One characteristic which these sprayers have
in common is a fan that generates the mass of air which carries
droplets of pesticide suspensions to the target area. The manage-
ment and control of all major orchard pests affecting leaves, twigs
and fruit (diseases, insects and mites) is dependent upon timely
pesticide sprays applied to all areas of the tree. In orchard
spraying, the spray target often is not the specific pest being
controlled (insect, mite or fungus spore) but rather the leaves or
fruit on which it may be present or to which it may visit after the
spray has been applied. The target, thus being the tree which is
extremely variable in size, shape, density, and row spacing, has
created a need for different types of sprayers. Sprayer manufactur-
ers responding to these needs have produced airblast sprayers which
are so diverse that a grower in America can buy just about any
type he may need for his orchard operation.
Because of the gradual change from standard size trees to
semi-dwarf and dwarf types most growers in the mid-Atlantic states
have needs for a sprayer that can be used to spray conventional
size standard apple trees as well as dwarf apple, peach and cherry.
The amount of spray mixture used per acre is another variable that
has to be adjusted depending on tree type and size. The amount
commonly used varies from 400 gal/A (gpa) in dilute sprays for
mature standard apple trees to 10-20 gpa with low volume sprayers.
Ultra low volumes of as little as 1.0 to 3.0 gpa have been used
with special sprayers but this usage is still very limited. With
this magnitude of variation in tree size and spray volume used and
the wide range of sprayers available with just about any size tank,
it is understandable why growers are often confused when buying a
sprayer. To add to the confusion, descriptive phrases such as cfm
air volume, air velocity range, dual adjustable blower, axial flow
and centrifugal fans, mass median diameter of droplets, shear, disc,
mistifier and spinning nozzles, touch command meters, flip over
nozzle, and fluid agitation often are used to reveal the wonders of
each specific sprayer.
1
Appeared in the Maryland Fruit Grower 49(4): 2-6, 1979 and the
Pennsylvania Fruit News . April, ly/y. Reprinted with permission
of the author.
Conventional vs. Low Volume Sprayers
Orchard airblast sprayers available today may for convenience
sake be placed in one of three major categories, i.e., conventional,
low volume and ultra low volume.
The conventional type airblast sprayer commonly used today and
during the past decade was designed to apply both dilute and semi-
concentrate rates which ranged from 500 gpa to as little as 50 gpa.
These sprayers operate at a pump pressure from 30 to 400 psi that
force the spray mixture through a manifold on which several nozzles
(6 to 15 per side) are located. Variable nozzle sizes may be sel-
ected which regulate the sprayer delivery rate as well as the range
of droplet size produced. The droplets are discharged into the
airstream which range in velocity from 80 to 120 mph and in volume
from 25,000 to 90,000 cubic feet of air per minute (cfm) . Air volume
specifications for orchard airblast sprayers in the past have been
highly controversial and their accuracy questionable to the point
where they are not often used today. The droplet size produced by
these machines has a wide range from 10 to 600 mu depending on pump
pressure and nozzle orifice size. The conventional sprayers are
effective in the application of 50 gpa or higher but are limited in
the application of smaller amounts.
In recent years sprayers designed to apply 5 to 20 gpa have
been introduced and widely used in many apple growing areas of
eastern United States. Similar type concentrate or low volume
sprayers have been used for the past 20-25 years in Europe, Africa,
Australia, Middle-East, Canada, and in several apple growing areas
of western United States.
The low volume airblast sprayer differs from the conventional
type mainly in pump pressure, air velocity and air volume. Pump
pressure ranges from 25 to 100 psi. Nozzles used on these machines
vary from 3 to 12 per side and are either a hollow-cone swirl nozzle,
a spinning nozzle, or an air jet which does not use swirl plates or
discs. The spray droplets are formed when the spray mixture is
injected into the airstream which may vary in velocity from 130 to
200 mph and in volume from 15,000 to 25,000 cfm. The high velocity
airstream performs two major functions: 1) that of a shearing or
impact action in the formation of droplets which range in size from
10 to 110 mu; and 2) as carrier of the droplets to all parts of the
target areas at high enough velocity for impingement.
Sprayers which may effectively dispense 1.0 to 3.0 gpa of spray
mixture are available and have been proven to be equal to other
sprayers in pest control. Uniform droplets are formed by a revolv-
ing porous sleeve powered by an electric 12 to 24 v DC motor. Sleeves
of porous metal or plastic are available which produce precisely con-
trolled droplets from 5 to 100 microns. The liquid pesticide formu-
lation or suspension in water are forced through the uniform pores
by centrifugal force generated by the spinning nozzle. The nozzles
are mounted in the airstream which may vary in volume and velocity
and the droplets are sheared off and carried to all parts of the tree.
The ultra low volume sprayer is the least tested to date and its
use is limited by relatively few pesticide formulations which can
be used. This type of sprayer has greater usage potential in the
future when pesticides may be delivered directly from their pack-
aged container to the tree without benefit of water as a carrier.
The low volume sprayers in general use in many parts of the
world are powered by the "power- take-off " on the tractor used to
pull them through the orchard but also may be engine operated.
They offer several advantages over the conventional sprayer:
1. Many of these machines cost less to purchase than conventional
machines since most have smaller tanks, low pressure pumps
and no motor.
2. They often are less costly to operate and maintain since
fuel consumption is less with only the tractor motor being
used in the spraying operation. Their simple design and
low pressure pump which wears at a much slower rate also
contributes to their low maintenance.
3. Spraying with these machines requires less total time
because more time is spent applying sprays to the trees
and less time in filling the spray tank and weighing out
chemicals. As much as 50°6 savings in spray time can be
realized with a change from 400 to 20 gallons per acre.
4. Reductions by 80-6 in the amount of water used has resulted
in a significant savings on farms v/here water is scarce
or must be transported for some distance. This reduction
in the amount of spray mixture used also eliminates the
need for a "nurse tanker" and operator often used in high
volume spraying.
5. Low volume spraying generally requires about 20-40% less
pesticide per acre than high volume spraying.
Factors Affecting Spray Deposits
Since the mass of air generated by airblast sprayers is the
major source of energy dispensed in carrying spray droplets to all
parts of the tree, some understanding of its character and factors
affecting it should be helpful in deciding the type of sprayer to
purchase. The airblast is generated by various types of fans and
may vary in volume and velocity depending on the particular design
or type. Droplets are either injected into the airstream through
nozzles which aid in forming droplets into a range of sizes from
30 to 600 microns (1.0 micron (mu) is equal to 1/25,000 inch or
0.001 mm), or the liquid is released into the airstream under low
pressure and is broken or sheared into droplets. This shearing
action is typical of the high velocity low volume sprayers commonly
referred to as mist-type sprayers.
the rate of evaporation. A droplet moving in an airstream must
have a certain minimum momentum in order to penetrate through the
layers of air flowing around it. Because of the greater influence
of drag force the smaller droplets traveling in relatively slow
airstreams tend to follow the random turbulent fluctuation of the
airstream more closely and therefore travel a more devious path
than the larger droplets.
Considering these facts it is evident that impingement of
droplets produced by low volume sprayers would be lower during
periods of low R.H. or in slow moving airstreams. Workers in New
York have shown that under conditions of high evaporative potential
which commonly occur during the growing season, spray droplets may
lose more than 40-6 of their original volume during transport time
from sprayer outlet to the foliage. They found that when the R.H.
was 95% there was only about 5% water loss at 30 feet from the
sprayer outlet, while 20-251 was lost when the R.H. was M% . Spray
deposits in the top of trees was only 37% as much at 351 R.H. as
when the R.H. was 951.
Summary of Conditions Affecting Airblast Sprayer Performance
A number of experiments designed to evaluate the performance
of several conventional and low volume sprayers for apple pest
control have been conducted in recent years. During the past 2
years Dr. L.A. Hull, Entomologist at the Fruit Research Laboratory,
and I have evaluated several sprayers for control of green apple
aphid and spray distribution patterns. Control levels of aphids
have been correlated with chemical deposits on leaves as measured
chemically using dicofol and visually using a fluorescent tracer.
A number of conclusions can be drawn from these experiments and
a summary of several follows:
1. Sprayer size and design directly affects spray coverage and
pesticide deposits and determines the size of tree that can
be properly sprayed. Conventional airblast sprayers having an
airmass volume of 65,000 cu. ft. per min. or greater with velo-
cities of 120 mph or more and the larger low volume sprayers
may be used effectively on standard orchard trees up to 22 feet
in height. Low volume sprayers of the small to intermediate
size v\?hich are power take-off operated perform better in dwarf
or semi-dwarf trees with heights of 12-15 feet.
2. The tree size in height and density directly affects the velo-
city of the airmass by blocking or slowing air movement and
subsequently affects the amount of chemical deposit. Sprayers
should have sufficient air volume and velocity to blow through
the top of the trees to be sprayed.
m
In a spraying system using air as the carrier o£ droplets
several factors are operative simultaneously which affects the
distribution pattern and quantity of chemical deposited. The
velocity and volume of the airstream, droplet size, evaporation
rate, ground speed and target distance all have individual effects
on the results obtained.
Droplet size and air velocity must be critically balanced to
obtain effective and efficient spray application. Spray droplets
of a predetermined size must travel at specific speeds in order
to remain in an airstream. Many tests throughout the years have
determined these critical speeds and have shown that as the velo-
city decreases the larger droplets drop out first followed by pro-
portionally smaller droplets as the velocity continues to decrease.
The rate of velocity decrease of different airstreams has been
found to be similar regardless of the volume. Thus, two airstreams
with similar velocities at the point of outlet but having drastic-
ally different volumes will also have similar velocities at 25 feet
from the outlet and both may be only 15 to 20 percent of their
original speed at this distance.
In view of this rapid velocity decrease with distance from the
sprayer outlet, droplet size becomes very important in the impinge-
ment of droplets on leaves and fruit which directly affects the
level of pest control obtained. The impingement of liquid droplets
on a solid surface such as a leaf or fruit depends largely upon two
factors; 1) the mass or size of the droplet, and 2) the velocity
at which it is traveling. Large droplets will impinge at low velo-
cities but also are the first to fall out of the airstream as the
velocity decreases. The smaller the droplets the higher the velo-
city required for their impingement but these droplets are carried
farther in slower airstreams. In slower airstreams droplets are
subjected to evaporation for a longer period than in high velocity
ones, thus decreasing their size further and diminishing their
chances of impingement. With conventional airblast sprayers the
air velocity at the outlet may be approximately 120 mph while at
25 feet away it often drops to 15-20 mph. In these airstreams if
proper droplet size is not carefully selected and distributed in
calibrating the machine the larger droplets fall out on the lower
parts of the trees while the smaller ones are carried farther but
not deposited in the upper portion of the tree. The end result is
often a poor spray distribution with heavy deposits on the lower
leaves and fruit which may be phytotoxic and inadequate pest con-
trol in the top of trees.
The effect of relative humidity (R.H.) on spray deposition
has been recognized and of concern to growers since the introduction
of airblast sprayers. The effect of a high evaporation rate due to
low R.H. on small droplets produced by low volume sprays is far
more significant than on larger droplets because droplet size and
momentum greatly affects rate of impingement. It has been shown
that the rate of evaporation of the total spray volume will be pro-
portional to the total sum of the diameters of the droplets compri-
sing the spray. Therefore, the smaller the spray droplets the greater
The rate of sprayer travel has a direct effect since air
velocity loss is proportional to the forward speed. Speeds
above 2.5 mph for standard trees and 3.0 mph for dwarf trees
are not recommended.
Evaporation rate of the droplet and droplet impingement is
directly correlated with relative humidity of the ambient air.
Spraying during low humidity (.35-50% R.H.) periods should be
avoided, particularly with rates less than 30 gpa.
Spray distribution in the tree as well as undesirable spray
drift is greatly influenced by wind conditions at the time of
application. No reliable tests under known wind conditions
have been conducted to measure effect on pesticide distribution
and deposits.
The level of pest control obtained is correlated with inoculum
or population pressure and the amount of pesticide applied.
The lowest deposits and level of pest control are in the top
of trees.
It is important to keep any sprayer properly adjusted to obtain
maximum performance. Frequently checks on pump pressure,
nozzle wear, operator speed and air delivery are essential to
dependable sprayer performance. It is particularly important
that the air velocity of airblast sprayers with shear-type
nozzles be checked frequently and maintained at between 165-200
mph.
Accurate calibration of airblast sprayers is essential for the
uniform application of orchard pesticides. (Details of proper
arrangement of nozzles to obtain proper distribution pattern for
conventional airblast sprayers are given in Figure 1.)
Upper 2/3
Effective
Airblast
Noz.
Discharge
No
GPM
6
105
5
0.83
4
0.63
3
0.45
2
0.34
-3
1-2.5
Lower 1/3
I-OFF
Effective
^"2.5 Airblatt
''OFf
REAR VIEW
OFF-hCV
2 5-t-O
OFFH-o
50%» 3.86 GPM
(3.76)
35% = 2.66 GPM
(2.72)
IS*- I.I4GPM
(113)
SIDE VIEW
100 GPA - 15.2 GPM (76 GPM/side)
ROMS 30 ft Speed 2.5 MPH
2 Hole Whirl Plote - 200 PSI
SPOTTED TENTIFORM LEAFMINERS: BIOLOGY, MONITORING, AND CONTROL
Ronald J. Prokopy, Robert G. Hislop, and William M. Coli
Department of Entomology
INTRODUCTION
From the early 1950's until 1978, spotted tentiform leafminers
(STEM) could occasionally be found in low numbers in unsprayed
apple trees in Massachusetts, but were rare in commercial Massa-
chusetts apple orchards. Since then, STEM have appeared in compara-
tively large and damaging numbers in some commercial orchards, esp-
ecially west of the Quabbin reservoir. Thus, in 1979 STEM mines
were found at levels of 0.1 or more per leaf in 12 of 13 orchards
sampled west of the Quabbin, but at this level in only 3 of 13 or-
chards sampled east of the Quabbin.
There are 2 species of STEM in Massachusetts: Phyllonorycter
crataegella and Phyllonorycter blancardella . More than 901 of the
STEM sampled by us in Massachusetts in 1979 were P. crataegella .
Recent studies by Dr. Richard Weires of the Hudson Valley
Fruit Laboratory in Highland, New York and by Drs . John Leeper and
Harvey Reissig of the Geneva, New York Experiment Station have clear-
ly shown that in New York, both these STEM have developed strong
resistance or tolerance to azinphosmethy 1 (Guthion) , phosmet (Imidan) ,
phosalene (Zolone) , carbaryl (Sevin) and several other broad- spectrum
insecticides commonly used in orchards over the past decade or two.
On the other hand, the principal parasites of STEM continue to re-
main highly susceptible to these insecticides. The result is yet
another instance of pesticide- induced population explosion, compar-
able to the situation we have experienced with spider mites over the
past 3 decades. The pest, no longer influenced by the effects of
pesticide and freed from the presence of natural enemies, is able to
multiply very rapidly.
Resistant populations of STEM were apparently first detected
in Columbia County, New York in 1974. Since then, such populations
have spread throughout most of the Hudson Valley and much of Connecti-
cut, and are now being carried into Massachusetts through natural
dispersal (often aided by warm southwest winds) and importation of
infested leaves in bins of apples from infested orchards.
Even in cases when the original introduction of STEM into an
orchard may have consisted of only a few resistant individuals, popu-
lation buildup may be very rapid. Each female lays an average of
25 eggs, and there are 3 generations per year. Hence, if there
were no egg, larval, or pupal mortality, a single 1st generation
mated female in May could give rise to more than 15,000 STEM larvae
by September. Fortunately, there is considerable natural mortality,
even in the absence o£ pesticide-resistant parasites or predators,
so that the full biotic potential o£ this pest is rarely if ever rea-
lized.
In this article, we will outline the biology and monitoring
methods of STLM, and suggest various possible approaches to control.
Drs. Weires, Leeper and Reissig have been studying these aspects in
New York since 1976. Much of what we will describe here is drawn
from their excellent work, some of which is published in the 1977
Proceedings of the New York State Horticultural Society , the August
1977 issue of the Journal of Economic Entomology , the March, 1978
issue of the American Fruit Grower^ and New York Food and Life
Sciences Bulletin 85 (1980")"^
BIOLOGY
Description of Stages and Life History . STLM overwinter as pupae
in apple leaves on the orchard floor. First generation adults begin
to emerge when Mcintosh trees are in the green tip stage of develop-
ment. The adults are small (about 1/8 inch long) light brown moths
with white wing spots that appear as transverse bands when the wings
are folded. Though frequently found resting in ground cover vege-
tation during the day, they are particularly active from late after-
noon through dusk, and may be found then on the undersides of leaves,
the tree trunk, or interior scaffold limbs. The tiny white eggs
(1/75 inch diameter) are laid singly on the undersurface of the leaves
and require about 6-10 days to hatch. First generation eggs are
laid predominantly on fruit-cluster leaves in the lower half of the
interior of the tree. Second and third generation eggs may be laid
on any leaves anywhere in the tree. In addition to apple leaves,
leaves of other trees such as crabapple, hawthorne, quince, plum, and
wild cherry may also serve as STLM hosts.
The larva develops in the same leaf on which the egg was laid.
Larvae develop first through 3 sap-feeding stages and then 2 tissue
an irregular oval, circumscribing the area within which the larva
will eventually develop to maturity. By the 3rd larval stage, the
lower leaf surface tissue circumscribed by the trail will have a light
green or whitish appearance and can be readily removed, revealing
the feeding larva. Tissue feeding larvae feed just below the upper
surface, producing tent-like mines with whitish spots visible when
the green tissue has been eaten. The last-stage larva transforms into
a pupa in the leaf tissue, with the pupal stage lasting about 10 days.
The entire life cycle requires about 35-55 days, depending on weather
conditions .
Mines o£ 1st generation larvae can be first detected in late
pink or bloom, those of 2nd generation larvae in late June or early
July, and those of 3rd generation larvae in mid or late August.
Generations may overlap owing to the extended period of egg-laying.
Injury . STLM do not directly injure apple fruits. Rather the dam-
age results from injury to the leaves caused by larval feeding.
There is some suggestion, not yet confirmed that STLM larval feeding
interferes with the ability of leaves to produce or transfer to fruit
a hormone which inhibits ethylene production by the fruit. STLM
injury may result in greater than normal concentration of ethylene
within the atmosphere of the tree canopy.
Principal effects of extensive STLM larval feeding on Mcintosh
and other earlier-season cultivars such as Milton, Early Mcintosh,
Wealthy, and Puritan may be early ripening of fruit, premature fruit
drop, reduction in fruit size and color, reduction in fruit firmness
and storagability , and/or reduction in fruit set the following year.
Additional effects of STLM feeding may be: (a) greater sus-
ceptibility of larval-infested leaves to phytotoxic effects of insecti-
cides, fungicides, or calcium chloride nutrient sprays; (b) reduced
capability of larval-infested leaves to absorb growth-regulator
sprays applied to prevent early fruit drop or promote ripening, or
(c) compounding of detrimental effects of large spider mite popula-
lations, low plant nitrogen, or poor pruning.
In New York, there have been little or no detrimental effects
of large STLM populations on Red Delicious.
Natural Enemies . Several species of tiny wasps have been found
parasitizing STLM larvae in New York and Southern New England. The
parasite larvae hatch out from eggs deposited in STLM mines and suck
out the body fluids of STLM larvae. In Massachusetts, we have found
at least 5 such parasite species, the most abundant of which is
Apanteles ornigis . Among 9 Massachusetts commercial apple orchards
We speculate that there might be a more or less continual immig-
gration of parasite adults from unsprayed trees into commercial or-
chards during the growing season. However, regular application of
insecticide from petal fall through early August undoubtedly kills
most adults immigrating at this time. This is borne out by the fact
that both Weires and we find very little parasitism of 1st and 2nd
generation STLM larvae. Adoption of integrated pest management tech-
niques and corresponding reduction of unneeded insecticide applications,
especially in July, could open the way to increased levels of para-
sitism of 2nd generation larvae. Termination of insecticide appli-
cations by early August may allow comparatively high survival of
parasites attacking 3rd generation larvae. Such parasitism of these
larvae, together with natural enemies feeding upon overwintering
STLM pupae, could result in substantial mortality to overwintering
numbers of STLM.
10
MONITORING
Adults . STLM Adult seasonal activity may be monitored by employing
St icky traps baited with synthetic female sex pheromone caps (obtain-
able from Conrel Corporation, 110 A Street, Needham Heights, MA).
Adults can also be captured on white sticky-coated visual
traps used for monitoring tarnished plant bug and European apple saw-
fly adults (obtainable from New England Insect Traps, Box 938,
Amherst, MA). In 1980, we plan to assess which color of visual trap
is most attractive to STLM adults. At present, there is no reliable
means of relating numbers of adults captured in pheromone or visual
traps to potential injury levels. Future research is aimed in this
direction.
Larvae . In most orchard situations, the most useful monitoring method
to date has proven to be examination of the leaves for STLM larval
mines. For 1st generation larvae, leaf monitoring should begin at
late pink and continue at 4-7 day intervals until 1 week after petal
fall. For 2nd generation larvae, monitoring should begin in late
June and continue at 4-7 day intervals through late July. Monitor-
ing of 3rd generation larvae is unnecessary, as the New York research-
ers have found that while these larvae cause characteristic mines,
this injury occurs too late in the season to threaten the crop or
warrant additional insecticide applications.
For monitoring , it is best to examine at least 10 leaves per
tree on at least 1 tree per acre. For 1st generation larvae, choose
fruit cluster leaves at head height in the lower half of the tree in-
terior. For 2nd generation larvae, choose leaves on new woody tissue
(but not water sprouts) from anywhere in the tree.
It is extremely important to look carefully for evidence of
earliest sap-feeding mines on the lower leaf surface. This is best
done by holding the leaf toward the sky, and locating the thin wind-
ing brown trail and/or the light green or whitish appearing mine.
CONTROL
One or a combination of the following 3 pesticide- treatment
programs may be used for STLM control. Research conducted in New
York and Canada shows that high levels of adult immigration and/or
high overwintering mortality of STLM pupae render the previous year's
level of STLM abundance in a given block of little value in predict-
ing this year's STLM abundance. Thus, each grower should keep a
careful eye on each block during the current growing season.
A. Endosulfan (Thiodan) Program . This program is aimed at control-
ling STLM adults and consists of 1 application of endosulfan
(half strength) at half inch green and a 2nd application (full
strength) at pink against 1st generation adults, and/or an
application of endosulfan (full strength) in late June or early
July timed to coincide with emergence of 2nd generation adults.
11
Pre-bloom application o£ endosulfan will also give good control
of plant bugs. In some years, such as 1979, emergence o£ over-
wintering adults may be strung out, and a pink application of
endosulfan may not have sufficient residual activity to carry
over and kill adults emerging after petalfall. Best results
will be obtained if application is made in the evening, when ad-
ults are most active, and if trees are well pruned to facilitate
pesticide coverage.
One of the major advantages of this program is that endosulfan
has very little adverse effect on the principal predators of
spider mites and aphids in Massachusetts, and is therefore fully
compatible with an integrated pest management program.
Methomyl (Lannate) Program . This program is aimed at control of
STLM larvae in mines and consists of 1 petalfall application of
methomyl (full strength) directed at 1st generation sap-feeding
larvae and/or 1 application of methomyl (full strength) in July
against 2nd generation sap-feeding larvae. Application should
be made only if STLM populations reach or exceed an average of
1 mine per leaf at petalfall or 2 mines per leaf in July. Petal-
fall application of methomyl will control green fruitworm and
leafrollers but will not control plum curculio.
The need for precise timing and proper concentration of methomyl
application can not be over-stressed. Application at less than
full strength may give poor control. Delay of application until
many larvae have reached the tissue- feeding stage may not only
result in poor control, but more importantly, may seriously exacer-
bate phytotoxic effects of a variety of insecticides and fungi-
cides, as well as calcium chloride sprays.
To illustrate, we are familiar with a situation in 1979 when a
grower applied methomyl against 2nd generation larvae after a
substantial number of the larvae had already entered the tissue
feeding stage. Control was fair, but the resulting large amount
of phytotoxicity from subsequent fungicide and insecticide treat-
ments greatly exacerbated the adverse STLM effects on premature
fruit ripening and fruit drop.
Methomyl may cause severe injury to the foliage of many early
season apple cultivars and thus should not be applied to such
cultivars. Also, methomyl is a highly dangerous compound, re-
quiring careful use of a good respirator and gloves.
A major disadvantage of this program is the strong toxicity of
methomyl to mite and aphid predators which may result in large
spider mite and woolly apple aphid population buildup in mid- and
late summer.
12
]. Oxamyl (Vydate) Program . This program is aimed at control of
STLM adults and larvae and consists of 1 application of oxamyl
(half strength) at pink directed against 1st generation adults
and larvae and/or 1 application (full or half strength) in July
against 2nd generation larvae. The latter application should be
made only where sap- feeding mines reach or exceed an average
of 2 per leaf. Massachusetts has received a special 24 (c)
registration for use of oxamyl on bearing apple trees in 1980.
Inasmuch as oxamyl will not control plant bugs, an additional
pesticide should be included in pre-bloom treatments for this
purpose. Oxamyl has thinning effects, and should not be applied
at pctalfall or for 30 days thereafter. Because oxamyl is sys-
temic and has better residual activity than methomyl, timing of
application may be somewhat less critical than with methomyl.
Also oxamyl may be used with much less risk of phytoxicity than
methomyl on early ripening apple cultivars.
There are 2 major disadvantages of this program. First, oxamyl
is an extremely dangerous compound, having caused considerable
sickness among a number of Hudson Valley growers in 1979. Its
inhalation toxicity is many times greater than that of methomyl.
Use of a good respirator and gloves is an absolute must. Second,
oxamyl, like methomyl, is highly detrimental to mite and aphid
predators, although it may provide some degree of spider mite
control during the first years of use before resistance develops.
Be prepared for eventual outbreaks of spider mites and aphids if
you use oxamyl.
CONCLUSIONS
The information gained by New York researchers during 5 years
of recent experience with STLM is of im.mense value to our ability
to cope with the new insecticide- resistant strains of STLM entering
Massachusetts orchards. Several of the possible measures aimed at
controlling this pest pose a serious threat to the survival and build-
up of spider mite and aphid predators in integrated pest management
orchards. However, if growers use discretion in application of
measures for STLM control, and employ control measures only when
truly necessary and at optimal times, then the chances for success-
ful integrated pest management in the future are greater. In this
regard, treatments against 1st generation STLM larvae will have much
less adverse effect on beneficial predators than treatment against 2nd
generation larvae. We must be very careful not to apply excessive
numbers or rates of those few materials currently effective against
STLM, lest we induce rapid development of STLM resistance to these
materials. Further research by colleagues in New York and other
surrounding states, coupled with our own studies here in Massachusetts,
will hopefully lead to less hazardous and less disruptive means of
controlling STLM in the future.
13
MORE ABOUT NEMATODES AND FRUIT TREES
R.A. Rohde
Department of Plant Pathology
A university student majoring in pomology probably wonders
sometimes how, with all of the potential problems, a new orchard
is ever established. Problems with soil structure and fertility,
drainage, toxic decomposition products from fruit tree roots,
soil fungi, bacteria, viruses and nematodes can all injure young
trees. Sometimes the injury has a name such as crown gall,
collar rot or SARD (specific apple replant disease) but more often
the result is slov; or uneven growth that is difficult to diagnose,
or even measure. Sometimes trees die from winter injury but were
weakened by poor growth the previous summer.
Nematodes are one of the many factors contributing to the re-
plant problem. Nematodes are microscopic worms which live in
the soil along with bacteria and fungi and feed on root tips.
The feeding process injures or kills root tips and leads to pro-
blems of water and nutrient absorption. The resulting wounds
usually become infected by root rotting fungi. In addition,
some nematodes can transmit virus diseases.
A vigorously growing, mature tree can support a large number
of nematodes without showing any symptoms. However, trees coming
from the nursery, especially those in poor condition or being
planted under adverse conditions, cannot tolerate this damage.
Experiments at Cornell University and elsewhere have shown that
the head start given to small trees by soil treatment is never
lost even when high nematode populations return after a year or
two .
Soil samples from Massachusetts orchards always contain plant-
parasitic nematodes, usually of several different species. The
three most common, and most injurious, are the lesion, dagger
and ring nematodes.
Lesion nematodes, Pratylenchus spp., migrate through the inner
root tissues breaking them down as they feed. Injury on peach
trees is much more severe than on apple because peach roots contain
the cyanide-producing compound amygdalin (also known as laetrile) .
The cyanide produced in injured tissue increases the amount of
damage. Tissues killed by lesion nematodes are quickly invaded by
root-rotting fungi and bacteria.
Dagger nematodes, Xiphinema americanum , have spears which pene-
trate into the root tip and cause it to swell and stop growing.
Dagger nematodes can transmit the virus that causes peach stem pit-
ting or apple brown line and theoretically only one infective nema-
tode is necessary. The virus is not common in Massachusetts, but
it is present.
14
Ring nematodes, Criconemoides and Macroposthonia , are root
surface feeders. Injury is not severe, but helps to slow down
the growth of young trees. Other species of ring nematodes are
part of the "Slow Decline of Peach" complex in South Carolina.
Soil sampling . Because nematodes are distributed in clusters
throughout the field, it is important to collect soil from
several areas. For each 5000 sq. ft. area, 10 or more subsamples
taken to a depth of 8-10" from the strip where trees are to be
planted should be collected with a trowel or spade. Mix the soil
in a bucket and then put one quart of mixed soil in a plastic
container. If a sampling tube is used, about one quart of soil
should be collected.
Soi] samples may be taken at any time during the year although
winter and spring populations will be low and less representative
of the potential of the population to build up. Samples should
be sent to one of the Regional Fruit Specialists or directly to
the Department of Plant Pathology, University of Massachusetts,
Amherst, 01003. Remember, dried out soil is useless .
Sampling soil and extracting, identifying and counting nema-
todes is time-consuming and requires a fair amount of experience
and training. But the most difficult step comes next, when a
prediction should be made about how much injury might be expected
and what control methods, if any, should be used. The experience
of the grower is invaluable at this point because he will often
know if problems have occurred in this area in the past and the
overall potential of the area to produce fruit trees.
Soil fumigation . Treatment before planting to reduce all
disease organisms is probably still the best procedure and has been
discussed at length before ( Fruit Notes 41 (6): 3-5, 1976).
Fumigation is expensive, requires extensive preparation and special-
ized equipment, and does not always fit in well with the planting
schedule.
Planting hole treatment . Several insecticide-nematicide chemi-
cals have been used as root dips or mixed with soil around thej^p,.
tree as it is planted.. All of these materials, oxamyl (Vydate^ ^ rp^
phenamiphos (Nemacur^ ^), aldicarb (Temik^ ^), carbofuran (Furadan^ ^
are highly toxic to humans and are at least partially systemic. At
present time, only oxamyl is registered for use in Massachusetts,
and only on non-bearing fruit trees.
The "state of the art" at present calls for caution. There
is enough preliminary evidence to suggest that replant problems
exist and treatments will pay off. Because so many factors are
involved and because each orchard, indeed each block, is a different
ecosystem, small scale field trials are necessary in order to esta-
blish the value of any one particular treatment.
Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
R. S. Whaiey
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. 45 No. 3
MAY/JUNE 1980
TABLE OF CONTENTS
The Way You Fertilize Your Fruit Trees Can Affect the
Quality of the Fruit You Harvest
Suggestions for Use of Calcium Sprays in 1980
Suppressing Weed Growth Under Fruit Trees
Pomological Paragraph
Influence of Pruning Peach Trees Late in the Spring
The Use of Promalin to Elongate Delicious Apples:
Research Observations and Suggestions for Use in 1980
Soil Management of Peach Trees
Sampling Methods and Provisional Economic Threshold
Levels for Major Apple Insect and Mite Pests in
Massachusetts
Managing Mummy-Berry Disease of Blueberries in
Massachusetts
THE WAY YOU FERTILIZE YOUR FRUIT TREES
CAN AFFECT THE QUALITY OF THE FRUIT YOU HARVEST
William J. Bramlage, Mack Drake, and William J. Lord
Department of Plant and Soil Sciences
In the first half of this century, studies of the fertilizer
needs of fruit trees focussed on what was needed to maximize tree
growth and fruit yield. In the last couple of decades, however,
attention has turned toward the effects of nutrition on the quality
of harvested fruit. While the effects of calcium (Ca) deficiency
have been the driving force behind the reconsideration of mineral
needs, effects of nitrogen (N), potassium (K) , magnesium (Mg),
boron (B) and phosphorus (P) levels in fruit on their postharvest
quality have been noted.
It is clear that the mineral composition of fruit at harvest
is an extremely important factor in determining how well fruit will
keep after harvest. Most of the research on this problem has been
on apples and to a lesser extent, pears, but presumably the same
relationships also have some relevance to postharvest problems with
other kinds of fruit. It seems appropriate to review these relation-
ships between fruit nutrition and fruit quality as we enter into a
new growing season.
Calcium : In 1936 bitter pit was found to be related to low Ca
levels in apples. Thirty years later it could still be stated that
"Inspite of the very low Ca status of many orchard so ils ... there
have been few reports of direct responses by bearing apple trees to
Ca..." ( Temperate to Tropical Fruit Nutrition , Norman F. Childers,
Editor.) Today, however, there is strong concern about Ca levels
in apples and pears just about anywhere in the world that they are
grown .
At first, this concern was directed at bitter pit and cork spot
but today we know that many physiological disorders may be at least
partly related to low Ca levels in the fruit. In warmer fruit grow-
ing areas, cork spot and bitter pit remain the most serious effects
of low Ca, but in cooler areas various forms of internal breakdown
are the most serious Ca-def ic iency problem. In British Columbia,
Canada, the 'Spartan' apple industry was almost destroyed by break-
down problems before methods of raising fruit Ca levels were success-
fully developed.
Many approaches have been taken to try to raise fruit Ca levels.
Since Ca is less available in acid soils, regular liming programs are
essential in areas of low soil pH. Calcitic lime is more soluble
and is preferable to dolomitic lime unless Mg deficiency exists,
since dolomitic lime supplies little available Ca to the soil. Use
of calcium nitrate (Ca(NO ) ) as a source of fertilizer N is often
recommended, and we have round that it can provide a small increase
in fruit Ca levels. In areas where soil is droughty, irrigation is
often recommended to maintain Ca uptake by the tree roots.
Foliar sprays with Ca salts are the most direct way of insur-
ing adequate fruit Ca levels during growth. There is little move-
ment of Ca into fruits by the tree as long as vegetative growth
is abundant, so the value of sprays is that it places Ca directly
on the surface of the fruit, where it can be taken in by the fruit
if conditions are appropriate. At first, Ca (NO ) sprays were
recommended, but tests with many other Ca compounds have shown that
calcium chloride (CaCl ) is generally the most effective material.
Leaf injury from CaCl can prevent its use in many growing areas,
but in Northern North America it can be used if proper precautions
are taken. Frequent applications throughout the growing season
are usually the most effective way of applying CaCl„. A single
massive application shortly before harvest substantially raises fruit
Ca and improves keeping quality of apples. This idea originated in
British Columbia and we have tested it extensively, but we believe
that the severe foliar damage, the potential for fruit injury or
preharvest drop, and the residue that may be objectionable in hand-
packing operations make it an unlikely commercial practice.
Post-harvest dips in CaCl „ -containing solutions reduce soften-
ing and breakdown during storage. The use of a thickening agent
greatly increases the effectiveness of a dip, but thickeners leave
an objectionable residue that can be very difficult to remove. High
concentrations of CaCl„ must be used, and these can cause corrosion
of metal and injury to fruit, and may also leave a noticeable resi-
due. However, in the appropriate circumstances much benefit can
be obtained from a dip. In New England, fruit growers have preferred
foliar sprays, but postharvest dips are an alternative.
Nitrogen . To stimulate growth of young trees, N is usually
applied at high rates. Fertilizer rates should be reduced when
cropping begins, but they are sometimes continued because yields can
be increased. Even when N application is reduced when cropping begins,
the trees may continue to be supplied with excessive amounts of N
from the large reserves that have accumulated in the soil, sod and
tree. We have found that high N levels in trees fall very slowly
even when no additional N fertilizer is supplied.
Excessive amounts of N in the tree and fruit can severely reduce
fruit quality. The vigorous growth that it encourages reduces the
Ca level of the fruit. Moreover, the high N fruit tend to be larger,
greener, softer, more subject to preharvest drop, and to have more
cork spot and bitter pit. These fruit also tend to develop greater
amounts of scald, bitter pit, internal browning, and internal break-
down during and after storage.
Over-fertilization with N is probably very common. In the Paci-
fic Northwest it has been estimated that 50 to 75% of apple orchards.
and a smaller percentage of pear orchards, are excessively high in
N. The effects of high N on apples are perhaps being masked at
harvest by use of growth regulators, especially Alar, but growth
regulators cannot mask their consequences after storage.
Until recently the cheapest form of N was usually the one chosen
for fertilizing orchards. It is now recognized that the form of N
as well as the total amount of N that is used can influence fruit
quality. USDA researchers first found that ammonium (NH.) forms of
N can intensify Ca deficiency in apples by interfering with absorp-
tion of Ca by roots. It has been recommended that NH. -contain ing
fertilizers not be applied to apple orchards before or soon after
bloom if growers are concerned about fruit Ca levels.
the
Use of Ca
roots and a
(NO ) ^as
void!
Is NH
an N-source both supplies available Ca to
interference with Ca absorption. Our
experiments with use of Ca (NO ) rather than NH.NO show that Ca(NO )
may produce a small Increase in fruit Ca levels, but that this is
not enough to correct Ca deficiency if it already exists. Whether
the additional cost is justified by the benefit is a question for
growers to decide.
Our experience leads us to conclude that the total amount of
N being applied to fruit trees is a more important concern to fruit
quality than is the form of N that is being used.
Po tassium : K deficiency reduces growth and yield of trees and
severe K deficiency in apple and pear trees causes "leaf scorch",
a browning of the leaves. K deficiency has only a mild effect on
fruit quality, reducing acidity of the fruit and reducing red color-
ation. Excessive amounts of K in fruit are a greater danger to fruit
quality, since they lead to increased scald, bitter pit, and internal
breakdown after storage.
Fruit accumulate large amounts of K, and large yields can remove
a large amount of K from an orchard. Therefore, fertilizing with
K is most likely to be needed after a large crop. Nevertheless, fruit
quality will suffer far more from excess K than from deficient K.
Most of the effects of high K are the result of its interference with
Ca in the fruit, and too much K will generally have the same effects
as too little Ca.
Magnes ium : Mg deficiency can produce weak and unproductive trees,
and cause increased preharvest fruit drop, and its distinctive color
patterns on leaves have often been observed. It may be corrected by
application of dolomitic limestone or by foliar sprays with materials
such as Epsom salts. There is little evidence that either too little
or too much Mg directly affects fruit quality. However, excess Mg
interferes with Ca just as does excess K, so excessive amounts of
Mg will produce Ca deficiency effects in fruit.
Phosphorus ; P deficiency can reduce tree growth and yield,
and in several parts of the world it has also been shown to cause
increased amounts of breakdown of apples during storage. However,
in North America there has been very little evidence for P defic-
iency in fruit. However, we have recently found that high levels
of P in apples, especially in combination with low levels of Ca ,
greatly increased breakdown of apples during storage.
Boron : B deficiency has occurred over much of North America,
causing both internal and external cork development in fruit. Ex-
cessive levels of B in fruit can cause earlier maturation and
increased amounts of watercore at harvest, and increased amounts of
breakdown after storage. Thus, a moderate level of B is important
for good fruit quality.
B also influences Ca movement in the tree. If it is deficient,
less Ca is moved to the fruit and Ca deficiency can result. It
is therefore important to maintain adequate B levels as a part of a
program to avoid Ca deficiency.
Periodic application of borax to the soil is a standard commer-
cial practice in many parts of North America. A widely used alter-
native is 1 or 2 foliar applications of a soluble form of B in sprays
shortly after blossoming, although it is not clear how much of this
B moves from leaves into the fruit.
It is clear that deciding on a fertilizer program for an orchard
is no simple matter. The awareness that Ca deficiency is common and
that it greatly increases losses of stored fruit has caused a thor-
/-i.ir>T-i ■»-Q_QTTo1.io<-n<-.r> <->f fQT-^^^^■7^:>^- ^>■ra<^^^r•oc U<i rnnrliiHp thflt from th
SUGGESTIONS FOR USE OF CALCIUM SPRAYS IN 1980
Mack Drake
Department of Plant and Soil Sciences
Calcium chloride (CaCl„) foliar sprays are recommended for
all growers, to increase the flesh Ca content of Massachusetts
apples. Higher flesh Ca can markedly reduce pit, cork and storage
breakdown .
Apply foliar sprays of CaCl„, starting about 3 weeks after petal-
fall and repeat at 2 week intervals totalling 6 or 8 applications.
Apply 6 pounds CaCl„ per acre per spray until mid-July. After mid-
July apply 8 to 10 pounds/acre spray. Use a technical grade CaCl^
such as Allied Chemical Flakes, 77-80% CaCl^. Other brands may be
equally suitable.
Experience In Massachusetts has shown that CaCl„ can be com-
bined with pesticide sprays. However there is limited evidence
that the combination of Captan or Guthion (azinphos methyl) 50 WP
and CaClj may increase foliar burn. DO NOT MIX CaCl^ AND SOLUBOR
SPRAYSl Always dissolve the CaCl„ in a pail of water and add this
last and when the spray tank is nearly full.
Foliar CaCl„ sprays may be applied dilute (300/acre) or up to
lOX concentration (30 gallons /acre) . In our research, flesh calcium
was increased more by concentrated than by dilute sprays. In 1977,
foliar CaCl sprays at 6X and lOX concentration were equally effect-
ive for increasing Mcintosh flesh calcium.
CaCl sprays can cause
more serious on Mcintosh than Delicious. Apple leaves are less
burn of leaf margins. Foliar injury is
pple ;
susceptible to CaCl burn after mid-July. Mcintosh growing on M7
may be more susceptible to foliar burn than ones on standard root-
stock. Weak or injured trees may be more susceptible than healthy
trees. Do not repeat a foliar calcium chloride spray unless at
least 1 inch of rain has fallen since the last application.
Foliar CaCl„ sprays should be continued until the apples are
harvested. Growers using alternate row pest control, should apply
CaCl„-water sprays in those rows that were missed.
CaCl„ is not a substitute for a sound soil-liming program.
Lime orchards to pH 6.5 with a Ca-Mg/limes tone containing 5-7% MgO.
***********
SUPPRESSING WEED GROWTH UNDER FRUIT TREES
Will iam J . Lord
Department of Plant and Soil Sciences
Growers have become concerned, particularly due to the root-
injury on apple and peach trees last winter, about the absence of
sod under their trees because of annual use of a contact herbicide
such as Paraquat CL* (paraquat) plus a soil sterilant (terbacil,
diuron, or simazine). Of more concern is the occurrence of soil
erosion and in some instances tree heaving. Therefore, growers
have expressed interest in re-establishing sod and then suppressing
grass and weed growth rather than eliminating this growth.
Dacamine*, Dacamine 4D*, paraquat or Dowpon*M (dalapon) appear
to be the logical herbicides to use for re-establishment and main-
tenance of sod under apple trees. Where heaving of trees has occur-
red applications of mulch and re-establishment of the sod may help
prevent it. In peach orchards, many of which are relatively small,
it might be feasible to substitute mulch for herbicides or use para-
quat or dalapon alone.
Trade name
The first year after herbicide applications are discontinued
broadleaf weeds like cinquefoll, dandelions, lambsquar t er s , ragweed,
and plantian will probably be the predominant types of vegetation.
If these weeds become troublesome by late-July or in August, Dacamine
or Dacamine 4D can be applied under apple trees for their control
without injuring grasses. Continue to use Dacamine or Dacamine 4D
in subsequent years as needed under apple trees until grasses are
re-established, then switch to dalapon or paraquat. Under peach
trees it will be necessary to use paraquat because Dacamine or
Dacamine 4D are not labelled for this crop.
Dalapon is labelled for grass control at 5 to 10 lbs. per acre
under apple trees (use the low rate for trees less than 4 years old)
and at 2 to 3-1/2 lbs. per acre under peach trees. Nevertheless,
5 lbs. per acre may be sufficient for apple trees of all ages.
Trials in the past showed that this rate in some instances merely
suppressed grass growth and in other instances, it eliminated 40-90%
of the grasses. Therefore, the degree of grass control with 5 lbs.
per acre is not predictable. However, users of dalapon may find
that lower rates are necessary under older trees where grass growth
is less luxuriant than under young trees.
The re-established sod probably will be a mixture of grasses
and broadleaf weeds; therefore, it may be necessary to control trouble-
some weeds with paraquat, Dacamine or Dacamine 4D since dalapon con-
trols only grasses.
A paraquat program alone also should be suitable for re-establish-
ment and maintenance of sod. Apply in spring under apple and peach
trees when grass is 10-12 Inches high. A repeat application may be
necessary in mid-July.
Studies by Hislop and Prokopy ( Fruit Notes 44(5): 6-8) showed
that dalapon had low toxicity to Amblyseius fallacis , the most im-
portant predator of red and two-spotted mites in commercial orchards
in Massachusetts. In contrast, in earlier studies Hislop et al . ( Fruit
Notes 43(4): 5-8) found paraquat highly toxic to A. fallacis . There-
fore, Hislop and Prokopy ( Fruit Notes 44(5): 6-8) suggested the use
of dalapon as the herbicide in integrated pest management programs.
These workers have not determined Dacamine or Dacamine 4D toxicity to
A. fallacis .
********************
POMOLOGICAL PARAGRAPH
Pruning well- feather ed trees at planting . If you receive well-
feathered trees from the nurseryman, it is Important to leave as
many favorably positioned branches on the trees as possible because
when all but 2 or 3 branches are removed, these tend to grow very
vigorously and develop narrow crotch angles when growing conditions
are favorable. Head the trees at 39", or 10 or 12" above the highest
useful branch, if the tree is well feathered. Don't head the
branches, or remove any more low branches than necessary. Heading
adds to the problem of excessive vigor on vigorous cultivars and
delays production. Low branches contribute to the total leaf
surface of the tree. Low branches and extra scaffold limbs can be
removed in subsequent years.
INFLUENCE OF PRUNING PEACH TREES LATE IN THE SPRING
William J . Lord
Department of Plant and Soil Sciences
Growers generally prune peach trees late in the spring so that
a fungicide can be applied immediately after pruning to help pre-
vent valsa canker. However some peach blocks are being pruned as
late as shuck split, which raises the question of the effects of
late pruning on tree growth, yield, and fruit maturity.
This question was tested by the late Dr. Leon Havis , of the
U.S. Department of Agriculture. In 1951, he determined the influ-
ence in pruning time on yield, size and maturity of fruit, shoot
length, and flower-bud development of Elberta peaches ( Proc . Amer .
Soc . Hort . Sci . 58: 14-18). The trees were pruned during the dor-
mant season, at full bloom, at shuck fall, 3 weeks after shuck fall,
or not at all. The study showed that among the pruned trees, those
pruned during the dormant season produced the largest crops. When
pruning was delayed until shuck fall or 3 weeks after shuck fall,
yields were less than on trees pruned at bloom.
Timing of pruning also affected fruit maturity. Fruit from
trees pruned at full bloom matured earlier than those from trees
during the dormant season or 3 weeks after shuck fall. Fruit
from trees pruned at shuck fall or from un pruned trees matured
earlier than those from trees pruned during the dormant season or
3 weeks after shuck fall.
Shoot growth was longer on the dormant-pruned trees but there
were not differences in growth among the trees pruned at full bloom,
at shuck fall or 3 weeks after shuck fall. The unpruned trees pro-
duced the shortest growth.
The largest number of flower buds per foot of shoot growth
occurred on the dormant-pruned trees. Trees pruned at full bloom
produced more flower buds per foot of shoot growth than those pruned
at shuck fall, 3-weeks after shuck fall, or those that were not
pruned .
8
Based on this study, it appears that in orchards where valsa
canker is not troublesome, dormant pruning may be advantageous from
the standpoint of more shoot growth and flower buds and higher yields.
Where valsa canker is troublesome, it appears advisable not to delay
pruning later than full bloom.
**********
THE USE OF PROMALIN TO ELONGATE DELICIOUS APPLES:
RESEARCH OBSERVATIONS AND SUGGESTIONS FOR USE IN 1980
Duane W. Greene and William J. Lord
Department of Plant and Soil Sciences
Promalin* has been used in orchards in Massachusetts for several
years to increase the length of Delicious apples. Increased use has
given us experience so that we may better and more safely use this
growth regulator. It is the purpose of this article to review our
research findings and update our recommendations for the use of Pro-
malin in 1980.
Coverage . Last year ( Fruit Notes 44(3): 4-8) we showed that the
absorption and/or translocation of Promalin was quite limited. This
is supported by our 1979 data showing that when a 25 microliter drop-
let of Promalin was placed on the flower petals there was no increase
in the L/D ratio** of fruit at harvest (Table 1 below).
Table 1. Effect of the site of Promalin application on the L/D ratio
of 'Richared Delicious' apples.
Treatment"
(microliters )
1978
L/D ratio
1979
1. Check
2. Petals, 25^
3. Petals, 150
4. Receptacle surface,
5. In calyx end, 25
6. Pedicel, 25
7. Spur leaves, 250
25
93c"
94c
99b
03a
03a
.91c
.91c
1.03a
1.04a
.97b
.90c
50 ppm solution containing 0.05% X-77 applied at full bloom. All
blossom clusters reduced to one flower and then hand po llina ted with
'Early Mcintosh' pollen.
A 25 microliter droplet was large enough to wet the receptacle and
pedicel surface with no runoff,
c
Numbers in a column followed by a different letter are significantly
different at odds of 19 to 1.
*Trade Name
**Larger the L/D ratio, longer the fruit
have an L/D ratio of 1:00 or more.
A "typey" Delicious will
A comparable amount placed in the calyx end of the receptable surface
resulted In "typey" fruit at harvest whereas treatments applied to
the pedicel (flower stem) we re intermediate. A 10-fold increase in
volume of Promalin applied to the spur leaves caused no fruit elon-
gation. Thus, 2 years of research indicates that it is essential for
the Promalin droplet to come in direct contact with the flower part
that eventually will become the fruit. Application to any other
part of the flower or spur has either no effect or a reduced effect.
Thorough uniform spray coverage is absolutely essential for a con-
sistent Promalin response.
Field Observations Following Promal i n Application
Within 2-3 days following a Promalin application calyx swell-
ing and closing is apparent, first on the king blossom and then on
lateral blossoms. Promalin merely accelerates that which normally
occurs on pollinated flowers. Ten to 12 days after application,
Promalin appears to increase fruit set. About 15 days after bloom,
yellowing of the pedicels occurs on many of the developing fruit in
the cluster. By 3 weeks after bloom most of the less vigorous fruit
have dropped and within 4 weeks fruit set has been determined and
subsequent drop is minimal.
Thinning Due to Promalin Application
It has been our impression, as a result of observations made
the past 2 years, that thinning due to Promalin may be more apparent
than real. We believe that Promalin causes earlier removal of many
fruit that would normally drop later. It would certainly appear
that Promalin was increasing thinning if you assessed fruit set 2-3
weeks after bloom. However in most situations it appears that Pro-
malin has advanced the 'June-drop' by about 2-3 weeks, thus giving
only the impression of thinning. While Promalin can indeed cause
thinning, caution should be exercised in concluding that this has
happened on your trees.
Chemical Thinning Following Promalin Application
Since Promalin applied by itself is capable of thinning, it is
important to know if excessive thinning is likely to occur if Pro-
malin treatment is followed by an application of Sevin* (Sevin is
the only chemical thinner recommended for use on Delicious in Massa-
chusetts). This is particularly important to know since it is well
established that the thinning responses may be increased when 2 dif-
ferent thinning agents are applied. We attempted to answer this
question in 1979.
In 1 experiment, Promalin at 25 ppm-plus-Glyodin was applied
as a dilute spray at full bloom (Table 2). (This is about a 3-fold
over-application since the label recommendation is for 125-150
gal/acre). Half the trees sprayed with Promalin-plus-Glyodin also
received Sevin about 20 days after bloom. Other trees received Sevin
alone. The Promalin-plus-Glyodin spray increased the L/D ratios of
the fruit but also caused thinning (Table 2).
*Trade Name
10
Table 2. Effects of Promalin and Sevin on thinning, fruit size,
L/D ratio, and seed number of 'Richared Delicious' apples.
Treatment '
(ppm)
Blossom
c lust er s
per cm
limb circ
Fruit
per 100 Fruit
per cm blossom Wt . L/D Seeds/
limb circ. clusters (g) ratio fruit
1. Check 12.6a-
2 . Proma 1 in 2 5 +
Glyodin 12.0a
3. Promalin 25 +
Glyod in +
Sevin 12.4a
4. Sevin 12.8a
8.1a
3. 7b
3.6b
6.6a
70a
31b
31b
52a
170ab .93b 5.0a
185a 1.03a 4,8a
146c 1.03a 2.5b
156bc .94b 2.7b
F.B. May 10, 1979. Promalin 25 ppm + 1 pt/lOO gal. of Glyodin applied
as a dilute spray on May 10, 1979. Sevin 1/2 Ib/lOO gal. applied
as
dilute spray June 1, 1979
Numbers in a column followed by
different at odds of 19 to 1.
different letter are significantly
However, the degree of thinning was not increased by the application
of Sevin about 20 days after bloom. Sevin alone did not cause thin-
ning. It is apparent that Sevin was taken into the trees because it
reduced seed number of the fruit, even though it caused no thinning.
The Promalin-Sevin combination appears to have reduced fruit size be-
low that of Promalin alone (Table 2), perhaps due to the reduction
of seed number.
In another experiment, Promalin concentrations of 25 to 100 ppm
were applied at full bloom as dilute sprays to another group of
Delicious apple trees. Sevin was applied as a dilute spray 20 days
after full bloom on half the trees in each treatment. Promalin alone
at 25 ppm caused no thinning (Table 3). Promalin at this cone entra t ion-
plus-Glyodin tended to increase the thinning response but the differ-
ence was not significant. Promalin alone at both 50 and 100 ppm
caused excessive thinning. The application of Sevin on half of the
Promalin-treated trees caused no additional thinning,
that the thinning response to Sevin in 1979 was not j
that previously received an application of Promalin.
drop was light and Sevin did reduce seed number. Therefore, under
different conditions thinning might have occurred.
Thus, it appears
;reater on trees
However , June
11
Table 3. Effects of Promalin at different concentrations on fruit
thinning of 'Red Prince Delicious' apples. 1979.
Treatmen t
Fruit/
Sevin cm limb circ. 100 blossom clusters
1. Check
2 . Promalin 25
3 . Promalin 25 +
Glyodin 1 pt/
100 gal.
4. Promalin 50
5. Promalin 100
+
5.2a"
3. 3abc
4. Sab
3.5ab
3.2bc
2 .9bc
2. 3cd
1. 7cd
0. 7d
0.6d
60a
4 3abc
45ab
36bc
41abc
31bc
25bcd
23bcd
9d
7d
Treatments applied May 10, 1979 at full bloom.
r
Sevin 1/2 lb/100 gal was applied to 1 limb per tree on June 1, 1979.
c
Numbers in a column followed by a different letter are significantly
different at odds of 19 to 1.
Variable Promalin Responses
Another concern of Promalin users in Massachusetts is the lack
of a consistent and predictable response. Sometimes fruit from Pro-
malin- t rea ted trees are similar to those from untreated trees; in
other years Promalin causes significant fruit elongation. It is our
feeling that Promalin always elongates fruit, provided that it was
applied near full bloom. Why then is there a variable response?
Promalin promotes at least 2 independent processes: fruit elongation
and fruit thinning. We believe that Promalin thins off elongated
fruit early in the season in the years when it appears not to be
effective. However, further observation will be necessary to confirm
this .
Suggestions for Promalin use in 1980
Calibrate your sprayer. Thinning due to Promalin has often been
traced to overapplicat ion because of improper sprayer calibration
and nozzle adjustment. The margin of error with Promalin is not
great. The label suggests that Promalin should be applied in
100-200 gal/acre. Therefore, an error in application of only
50 gal/acre can result in a 50% increase in the amount of Pro-
malin applied.
12
2. Do not apply more than 1-1/2 pts/acre of Promalin.
3. Do not apply Promalin when the temperature exceeds 85°F.
Excessively warm temperatures may increase the thinning
response without a corresponding increase in the shape re-
spons e .
4. Do not apply Promalin on young trees. A good rul e-o f- thumb
is not to apply this growth regulator on any tree until
it is bearing heavily enough to consider chemical thinning.
5. Apply Promalin as soon as weather permits after opening of
the king blossom. This is earlier than we have suggested
in the past. It is our feeling that the reduced leaf sur-
face at this earlier timing may reduce the possibility of
thinning .
6. The addition of surfactants or spreader stickers increases
both the fruit shape and thinning response to Promalin.
7. Our thinning trial in which an application of Sevin followed
Promalin usage was not conclusive. It is possible that no
thinner is needed on Promalin- treated trees. Therefore, we
urge you to carefully assess the need of Sevin prior to its
use .
8. Leave a few untreated and representative trees in the Promalin-
treated block. Initial fruit, subsequent drop and fruit
shape are never constant from year to year. Therefore, the
only way to accurately assess the performance of Promalin
in your orchard is to leave a few untreated trees in the same
block to indicate what would have happened in the absence
of the Promalin spray.
**********
SOIL MANAGEMENT OF PEACH TREES
Wi lliam J . Lord
Department of Plant and Soil Sciences
Peach trees withstand grass and weed competition during sum-
mers of inadeuqate rainfall less successfully than do apple
trees. We found in a study of 6-year duration that even though
13
we mowed the grass and broadleaf weeds under Jerseyland peach
trees 5 or 6 times annually they were generally lower in nitro-
gen, made less growth, and produced less fruit than those re-
ceiving annually 40 lbs. of hay, 2 applications of paraquat, 1
application of paraqua t-plus-s imaz ine mixture, or cultivation.
Peach trees produce well under the sod-plus-mulch system
of soil management in Massachusetts. An annual application of
a 40-lb. bale of hay under peach trees can produce growth and
yields comparable to those produced by cultivation. However,
mulch generally increases leaf potassium in comparison to culti-
vation, which may then depress leaf magnesium and calcium.
Wh
or sod
ges t ed
involv
diskin
is pre
and le
vat ion
leaf w
with h
moi s t u
age f o
dis t ur
is r el
zine ,
ches .
land W
your C
which
and b r
ere mul
wi th h
sy s t em
es only
g 1 or
f er r ed
s s apt
alone
eeds un
erbici d
re and
r peach
b the s
a t ively
dichlob
Sugges
eed Con
ounty E
are res
oadleaf
ch is
erbici
s o f s
parti
2 t ime
over c
to per
may fa
der th
es to
to mak
tree
oil an
inexp
enil a
t ions
trol C
xt ensi
is tant
weed-
not re
de- t re
oil ma
al inc
s to g
1 ear c
mi t so
il to
e tree
elimin
e i t e
borer
d the
e n s i v e
nd t er
for th
hart f
on Ser
to th
free a
adil
at ed
nage
orpo
ive
ulti
il e
give
s .
ate
as ie
con t
tree
and
baci
eir
or t
vice
es e
r eas
y availa
areas u
ment. T
ration o
adequate
vat ion b
rosion .
adequat
It f r equ
the comp
r to ob t
rol. Ch
root s a
easy to
1 are cu
use can
r ee f rui
Howev
herbicid
ble,
nder
rashy
f the
con t
ecaus
Neve
e con
en t ly
et iti
ain a
emica
s doe
appl
rren t
be f o
t s wh
er , w
es so
trashy
the tr
cult i
cover
rol of
e i t i
r thele
trol o
shoul
on for
dequa t
1 weed
s cult
y . Pa
ly lab
und in
i ch is
eeds s
met ime
cul
ees
vat i
cro
wee
s le
s s ,
f gr
d be
nut
e sp
con
ivat
raqu
elle
the
ava
uch
s in
t ivati
are th
on whi
p and
ds and
s s cos
trashy
ass an
suppl
r ien ts
ray co
trol d
ion an
a t , si
d for
New E
liable
as bra
vade t
on
e sug-
ch
shallow
grass
tly
cul ti-
d broad-
emented
and
ver-
o es not
d
ma-
pea-
ng-
f rom
mb les
he grass
Trashy Cultivation-plus-Herbicides
Trashy cultivati
to partially incorpo
unteer cover of gras
tree row or under th
quat or a paraquat-p
to 10 inches high (a
that is not easily r
used the year of pla
on the trunk of the
by early-July, and p
of the grass and wee
moisture deficit occ
plus-s imazine can be
on should commen
rate into the so
s and weeds . Th
e trees should b
lus-simazine mix
bout mid-May) .
eached when cult
nting ^^ care is
trees . A second
OSS ibly a third
ds under bearing
urs within 3 to
used as a singl
ce early en
il the cove
e herbicide
e applied ,
tur e , when
Spray the a
ivat ing . P
taken to a
applicatio
app 1 icat ion
trees may
4 weeks of
e applicati
ough in the spring
r crop or the vol-
spray in the
in case of para-
the grass is 8
rea under the trees
araquat can be
void getting spray
n will be needed
for quick kill
be needed if a
harvest. Paraquat-
on under trees
14
established a year or more. However, we found that annual grasses
and broadleaf weeds were not as readily controlled by the resid-
ual simazine in the soil from the annual applications of a para-
qua t-plus-simaz ine in early-May, as by 2 applications of paraquat
annually in early-May and mid-July.
Cultivation should cease by the middle of July in young
orchards where trees are vigorous, to help prevent excessive or
late growth which could make the trees more susceptible to cold
injury. Bearing trees should be cultivated late enough to pre-
vent grass and broad-leaf weed growth from affecting fruit size.
(The critical period is that of rapid swell 30 to 35 days
preceding harvest.)
At completion of cultivation s
to help supply organic matter and p
monly used is "cover rye" sown in S
to 2 bushels per acre. Rye will de
over winter, and be easily killed b
principle objection to its use is t
"disk it under" when wet weather pr
the spring. Growers who prefer a c
can use buckwheat (50 to 75 lbs . /A)
lbs. /A), or oats (2 to 3 bu./A). T
late-August. Oats probably will pr
ome growers sow a cover crop
revent erosion. Most com-
eptember at the rate of 1-1/2
velop a good stand, live
y disking in the spring. The
hat it may be difficult to
events early cultivation in
over crop that winter-kills
, Japanese millet (5 to 20
hese are sown in early to
ovide the best ground cover.
Sod-plus-Herbicides
The sod-plus-herbicide system of culture, besides being ec-
onomical and reducing soil erosion, has another advantage over
the trashy cultivation-plus-herbicide system of soil management;
it enables the grower to smooth the land and establish a sod in
the alley between the trees, which should help reduce bruising
when transporting fruit. The herbicides to use in conjunction
with the sod-plus-herbicide system of culture are discussed in
the previous section of this article.
Concern has been expressed about complete elimination of grass
and broadleaf weed cover under peach trees with herbicides. With
no snow cover, a soil free of vegetation might expose the trees to
a deep f r
herbicide
broadleaf
more, mat
had been
f er ed win
subs tant i
from wint
establish
weed grow
growth un
issue of
eeze and
studies
1 eaves
ur e p eac
heavily
t er in j u
at ed tha
er in j ur
ing sod
th rathe
der f rui
Fruit No
roo
wi t
inva
h tr
mul c
ry t
t a
y-
und e
r th
t tr
t es .
t in
h ap
ded
ees
hed
o ro
sod
Thus
r f r
an e
ees
15
jury as occurred in 1979. In all of our
pie and peach trees, annual grassy and
the treated areas by late summer. Further-
at the Horticultural Research Center that
at periodic intervals since planted suf-
ots in 1979. Nevertheless, it is well
or a mulch will help protect plant roots
, growers have expressed interest in re-
uit trees and then suppressing grass and
liminating this growth. Suppressing weed
is discussed in another article in this
************
SAMPLING METHODS AND PROVISIONAL ECONOMIC THRESHOLD LEVELS
FOR MAJOR APPLE INSECT AND MITE PESTS IN MASSACHUSETTS
Ronald J. Prokopy, William M. Coli, and Robert
Department of Entomology
G . Hislop
In our article on integrated management of apple insects and
mites in the Novemb er /December 1979 issue of Frui t Notes , we stated
that in a forthcoming issue, we would indicate how we make decisions
on need and timing of pesticide applications based on levels of
pest and natural enemy abundance in samples taken in IPM orchards.
This article presents such information.
T
per e
and b
near
at tac
at ea
week
stati
modi f
outsi
whem
of th
leaf
speci
visua
b r
very
enef
the
king
ch s
from
on ,
ied
de,
samp
e t r
exam
es .
1 or
i e f ly re
1-2 acr
icial sp
block pe
the fru
tat ion b
green t
fruit, f
random s
lower in
ling for
ee is re
ined ser
Each we
pheromo
view our s a
es in IPM b
ecies . The
riphery , in
i t immigra t
y a t eam of
ip until on
oliage or p
cheme, with
side , and u
plant- feed
moved durin
ves as a sa
ek the numb
ne traps ar
mpling procedures, we designate 1 tree
locks as a sampling station for pests
majority of sampling stations are
asmuch as most adults of major pests
e from outside the orchard. Sampling
2-3 scouts occurs once or twice per
e week before harvest. At each sampling
runing cuts are sampled according to a
samples divided equally among the lower
pper inside parts of the tree. Except
ing mites and mite predators, no part
g the sampling process. Each fruit or
mpling unit for a number of different
ers of pest insect adults captured on
e counted and removed.
A key element in our decision making process is what is termed
the "economic threshold level" (ETL) . We consider the ETL to be
the pest population density at which pesticide application is recom-
mended to prevent the population from reaching a level capable of
causing economic injury (= the amount of injury we estimate would
justify the cost of a pesticide application). We recognize that an
16
ETL is not a static level, but may fluctuate considerably from
one locale to another and from one year to another, depending on
a variety of environmental, biological, and economic factors. The
ETL's which we use in our IPM program are still highly provisional,
and will most certainly need to undergo substantial refinement in
future years, pending further research and fuller consideration of
the variables influencing ETL's. This is at least a beginning.
We employ the following sampling methods and ETL's for principal
pests and beneficial predators.
Tarnished plant bug . One sticky-coated 15 x 20 cm white rec-
tangle (New England Insect Traps, Box 938, Amherst, MA.) is hung
in each sample tree at about 0.7 meters above ground and about 0.5
meters from the outermost foliage to monitor adult plant bug popu-
lations. Traps are emplaced at the silver tip stage of apple bud
development and removed one week after petal fall. Based on our
previous research, the ETL for plant bug consists of an average
cumulative capture of 5 adults/trap for the initial pesticide treat-
ment, and 3 adult/trap (disregarding captures from 0-7 days
after the initial treatment) for a 2nd treatment.
European apple sawfly . One s t icky- coa t ed 15 x 20 cm white
rectangle (New England Insect Traps) is hung in each sample tree
at about 2 meters above ground and about 0.5 - 1 meter from the
outermost foliage (on the south side of the tree) to monitor the
abundance of sawfly adults. Traps are emplaced at the early pink
stage of bud development and removed one week after petal fall.
Based on our previous research, we use an ETL of average cumulative
capture of 4 adults/trap for the initial pesticide treatment, and
2 adults/trap (disregarding captures from 0-7 days after the initial
treatment) for a 2nd treatment.
Green fruitworms
From
fruit/sample tree /sample dat
fruitworm larvae, and evidenc
work of Chapman and Lienk in
set the ETL at an average of
pink through
e are examin
e of fresh f
New York as
1 larva or f
mid-June, 30 developing
ed for presence of green
eeding injury. Using the
a guide, we provisionally
resh feeding scar/tree.
Leaf rollers
Alto
pher
male
and
un ti
addi
samp
evid
in N
of 1
, Calif
omone c
leaf ro
redband
1 harve
t ion , f
le tree
ence of
ew York
larva
. ) bai
ap is
Her a
ed mal
s t , wi
rom b 1
/samp 1
fresh
as a
or f re
One Pherocon 1 CP trap (Zoecon Corp., Palo
ted with a synthetic redbanded leafroller sex
placed in the center of each block for monitoring
bundance (the cap attracts both obliquebanded
es). The traps are in position from green tip
th pheromone caps renewed every 6 weeks. In
oom until harvest, we examine 30 developing fruit/
e date for presence of leafroller larvae and
feeding injury. Using the research of Reissig
guide, we provisionally set the ETL at an average
sh feeding scar/tree.
Plum curculio . We examine 60 developing fruit/sample tree/
sample date (1 or 2 sample dates/week) from petal fall through mid-
June for evidence of fresh curculio egglaying scars. The ETL is
provisionally set at 1 fresh egglaying scar among the 300 or 600
fruit sampled/block.
with
cent e
The t
caps
ETL,
Sco t i
of fi
trap
ly.
again
Co dlins moth .
et ic c
a synth
r of ea
raps ar
renewed
based u
a growe
rs t-gen
= pes t i
A captu
St codl
eh bio
e in p
every
pon th
rs , is
erat io
cide a
re of
ing mo
One Pherocon 1
odling moth sex
ck for monitorin
osition from bio
6 we eks . Fo r i
e recommendation
set at cumulativ
n males: 60-100
pplication at 1/
10 males/trap af
th suggests that
CP^ trap (
pheromone c
g abundance
om through
ni t ia 1 pest
s of Embree
e capture o
, 100-200,
4, 1/2 or f
t er the fir
a second t
17
Zoecon Crop.) baited
ap is placed in the
of codling moth males.
August, with pheromone
icide treatment, the
and Whitman for Nova
f the following numbers
or 200 or more males/
ull strength, respective-
st pesticide treatment
reatment may be needed.
Apple maggo t . One unbaited, sticky-coated, 8.5 cm dark red
wooden sphere (New England Insect Traps) is hung in each sample
tree at about 1.5 meters above ground and about 0.5 - 1 meter from
the outermost foliage to monitor apple maggot fly abundance.
Traps are in position from late June until harvest. Once, in August,
other insects are removed and the sticky-coating replenished if
needed. The ETL can be briefly described as capture of 1 fly/block
7 or more days after the last insecticide treatment.
San Jose scale
We do not monitor San Jose scale abundance
on the twigs, but instead use the simplified method of Madsen and
colleagues in British Columbia: examination of fruit at harvest for
evidence of scale injury. Our ETL is provisionally set at 0.1%
of fruit infested with scale. Where this level is reached or
exceeded, we recommend for the following season 1 or 2 pre-bloom oil
treatments and/or a mid-June and early July application of diazinon
or Penncap (timed to coincide with crawler emergence).
Mites and mite predator
we pick 15 1
Augus t , imme
at the labor
principal mi
mite (ERM) ,
The principa
is Amb ly seiu
eaves /sampl
diately pla
atory in Am
te pests o
two spotted
1 mi te pred
s fallacis.
of 8 ERM and
300 ARM/leaf
ERM and TSM
eloped by Cr
oil applicat
TSM active
If any A
on an index
oft in Mich
ion against
e t re
ce th
hers t
f app
spid
ator
We
stag
, fal
s_. Fo r
e/ sample
e sample
b rush a
le in Ma
er mite
in Massa
use the
es / 1 eaf
lac is ar
of t
igan.
ERM
he ratio
Each y
eggs in
sampli
date
s in a
nd pro
s sachu
(TSM) ,
chuse t
follow
if no
e pr es
of A_^
ear , w
each I
ng mites and mite predators,
from mid-June through
portable cooler, and
cess the leaves. The
setts are: European red
and apple rust mite (ARM),
ts commercial apple orchards
ing ETL ' s : combined total
A. fallacis are present;
ent , we base our ETL for
fallacis /prey mites dev-
e recommend a pre-bloom
PM block.
Green apple aphid and aphid predators . From petal fallthrough
August, we examine 30 foliage terminals (the 10 most distal leaves
on 1st year woody growth, but not water sprout s )/ sample tree/sample
date for apple aphids , and eggs and larvae of the principal predators
of apple aphids in Massachusetts commercial apple orchards: the cecido-
myiid Aphidoletes aphidimyza , and the syrphid Syrphus ribesii . We
also examine 30 developing apples /sample tree/sampling date for pre-
sence of aphid honeydew droplets on the fruit surface. If there are
18
no predator eggs or larvae present, we provisionally set the ETL
at either 50% of the terminals infested with apple aphids (based
on work of Madsen and colleagues in British Columbia) or 10% of
the fruit with honeydew. If there are predator eggs or larvae
present, we base our ETL on an index of the ratio of predators/
aphids .
Woolly apple aphid . From early June through August, we sample
15 recent pruning cuts/sample tree/sample date for presence of
v7oolly apple aphids. The ETL is provisionally set at 50% of the
cuts infested with woolly aphids.
White apple leafhopper . From petalfall through August, we
examine 30 leaves /sample tr ee / s ampl ing date for leafhopper nymphs
and adults. The ETL, based on work of Madsen and colleagues in
British Columbia, is provisionally set at 0.25 active stages/leaf.
Spotted tentiform leafminer . From bloom through July, we
examine 30 fruitcluster leaves / sample tree/sample date for leaf-
miner mines. The ETL, based on work by Weires and Forshey in the
Hudson Valley of New York is set at 1.0 sap-feeding mines/leaf on
Mcintosh and Cortland and 3.0 sap-feeding mines/leaf on Red Deli-
cous for 1st generation larvae, and at 2.0 sap-feeding mines/leaf
on Mcintosh and Cortland and 6.0 sap-feeding mines/leaf on Red
Delicious for 2nd generation larvae.
CONCLUSIONS
As s
procedure
program w
tion of t
term valu
chuset t s
money req
level of
1-2 acres
scale wou
intensive
prove to
of our ma
more refi
and ETL's
ugges t e
s and E
ill req
he vari
e to IP
and oth
uired t
int ensi
) may t
Id be e
or mor
be more
j or res
ned and
for ma
d in th
TL's wh
uire CO
ables i
M scout
er r egi
o emplo
ty indi
urn out
conomic
e simpl
optima
earch g
yet s t
jor app
e int rodu
i ch we cu
nsiderab 1
nf luencin
s , grower
ons . Ul t
y all of
cat ed her
to be so
ally unfe
i f ied sam
1 from a
oals for
ill s impl
le insect
c t ion , many
rrently empl
e refinement
g them befor
s , and farm
imat ely , the
the sampling
e (1 samplin
great that
asible . We
pi ing proced
cost-benefit
the 1980's i
e and workab
and mite pe
of the
oy in o
and f u
e they
advisor
amount
proced
g s ta t i
usef uln
recogni
ures mi
point
s aimed
le samp
s t s .
above
ur ap
Her
will
s in
of t
ures
on pe
ess o
z e th
ght u
of vi
at d
ling
samp
pie
cons i
be of
Massa
ime a
at th
r eve
nab
at le
It ima
ew ,
evelo
proce
ling
IPM
dera-
long-
nd
e
ry
road
s s
tely
One
ping
dur es
19
MANAGING MUMMY-BERRY DISEASE OF BLUEBERRIES IN MASSACHUSETTS
D. R. Cooley, W. J. Manning, and S. J. McCouch
Department of Plant Pathology
Mummy-berry disease is caused by the fungus Monolinia vaccinii-
corymbosi. It is probably the most serious blueberry disease in Massa-
chusetts, though no accurate loss estimate is available.
In order to manage the disease, the disease cycle as shown on
the following page must be understood. The fungus is an Ascomycete
and produces two types of spores: ascospores and conidia. These
spores disseminate the fungus.
The disease gets its name from the so-called mummy berry which
allows the fungus to overwinter. This mummy is actually a 'fungal
mass which winters on the ground, and in the spring produces apothecia,
which look like small mushrooms. In the apothecia, ascospores are
formed. These ascospores are discharged in moist weather during early
spring, and land on leaves and twigs, where infections start. This
is called the leaf and twig blight stage, or bud and twig blight stage,
of mummy berry. As symptoms develop, conidia form in diseased tissues.
These secondary spores are disseminated by rain, wind and bees to
blossoms and other new tissues. The fungus grows into the blossoms
and tissue, invading the developing fruit. This is the blossom blight
stage of the disease. The fruit turns salmon-colored or grey by mid-
summer, and drops to the ground. There it becomes a mummy of mycelia.
The fungus overwinters in the mummified fruit.
Researchers (Ramsdell et al . , 1974, 1975) have found that ascospore
release is not closely correlated with the stage of the blueberry
plant's growth. Ascospores are generally present when the first green
tissue appears in the spring, and continue to be present through bloom.
Conidial release overlaps the end of ascospore release and continues
until after bloom. Ascospore release is inversely correlated with
relative humidity; conidia release is inversely correlated with leaf
wetness. A combination of drying and wetting stimulates release; max-
imum release periods come during dry periods following free moisture,
usually rain, on the leaves. After release, spores can travel at
least 1000 ft.
It has been concluded that inoculum is generally present in such
large amounts that protective chemical controls applied throughout
both primary and secondary infection periods are necessary to effect-
ively manage the disease (Ramsdell et al . , 1976). Since this strategy
is protective, it is based almost entirely on plant growth stages.
Cover spra s begin just before bud break, and continue until just
after petal fall. Early infections are effectively inhibited by tri-
forine (Funginex), applied at or just prior to bud break, and continuing
1
Extension Technician, Associate Professor, and Graduate Assistant,
respectively. Department of Plant Pathology, University of Massa-
chusetts, Amherst, 01003
20
*>e
■^^
"5 s
i
^^^;^ ^>=a<;;^^J^^^^
=A • E.go
^^^
^. ^?.E
.-,^ ' —— • /^/ .^^"^z
Berries
bush ai
mummii
a mumi
from
•y an
round
surface
5^
growing
blueberr
' underg
grouncJ
^ -^
Apothecia
mummified
inch or two
and on the
for t
f o rin
at 7
e f f e c
d u r i n
porta
mary
and r
ca t io
commu
the s
are n
wo CO
e).
to 10
t i ve
g the
nt pa
inf ec
aking
n of
ni cat
pring
o t cu
vers
Ther
day
agai
bio
rt i
t ion
und
50%
ion)
rr en
at 7 t
ea f ter ,
int erva
ns t the
ss om bl
n manag
can b e
er apo t
urea pr
This
ther ch
tly reg
o 10 day inter
cover s p rays
Is , depending
bud and twig
ight stage. C
ing the diseas
greatly reduc
heci a . Combin
ills is especi
is done when
emicals have b
is t er ed .
21
vals (the residual life of tri-
are made with benomyl (Benlate)
on rain. Benomyl is not very
blight stage, but it is effective
ultural controls can play an im-
e (Ramsdell et al . , 1976). Pri-
ed by cultivating between plants,
ing this practice with an appli-
ally effective (Stretch, personal
the apothecia start to emerge in
een used against apothecia, but
Resistant varieties are almost non-existent. Only one numbered
selection was reported resistant to both primary and secondary
infections (Nelson & Bi 1 1 enb ender , 1971). Of named varieties, Bluetta,
Collins and Darrow were somewhat resistant to primary infections.
Jersey, Rubel, Burlington, Pemberton and Dixi are the least suscept-
ible in New Jersey (Varney & Stretch, 1966), while Earliblue, Blue-
ray, June, Atlantic and Ivanhoe are most susceptible.
Re f er ences
Nelson, J.W., and H.C. Bi t t enb ender . 1971. Mummy berry disease
occurrence in blueberry selections test planting. Plant Diseas e
Reptr . 55: 651-653.
Ramsdell, D.C., J.W. Nelson, and R. Myers. 1974. An epidemiological
study of mummy berry disease of highbush blueberry. Phytopathology
64: 222-228.
Ramsdell, D.C., J.W. Nelson, and R.L. Myers. 1975. Mummy berry dis-
ease of highbush blueberry; epidemiology and control. Phy to -
pathology 65: 229-232.
Ramsdell, D.C., J.W. Nelson, and R.L. Myers. 1976. Interaction of
eradicant and protectant treatments upon the epidemiology and
control of mummy berry disease of highbush blueberry. Phy to -
pathology 66: 350-354.
Varney, E., and A.W. Stretch. 1966. Diseases and their control. In:
P. Eck and N.F. Childers (eds.). Blueberry Culture, Rutgers
Univ. Press, New Brunswick, N.J.
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. 45, No. 4
JULY /AUGUST 1980
TABLE OF CONTENTS
Progress Report:
Scion/Rootstock and Interstem Effects on Apple Tree
Growth and Fruiting
Soil, Tree, and Fruit Response to Lime and Type of
Nitrogenous Fertilizer Applied at Two Timings Under
Sturdeespur Delicious Trees
How Ethephon is Being Used to Advance the Maturity of
Apples in Massachusetts
Excessive Apple Bud Abscission in 1980:
Was It Caused by Tarnished Plant Bug Feeding or
Cold Temperatures?
PROGRESS REPORT:
SCION/ROOTSTOCK AND INTERSTEM EFFECTS ON APPLE
TREE GROWTH AND FRUITING
William J. Lord
Department of Plant and Soil Sciences
In 1976, in cooperation with 9 other states, we established
a planting of Empire and Millerspur Delicious trees containing an
8- inch interstem of M.9 on either MM. Ill, Antonovka, or Ottawa
11 rootstocks. The trees were small and weak at planting and we
have experienced significant tree losses
MM
Fig. 1 . An
a 8- inch M9
tween MJ-1.111
the scion cu
white line i
piece, and t
is painted o
of the tree,
the M9 5 temp
inches above
trees plante
duce more ro
picture) tha
piece is bel
that the dia
is larger th
stock or sci
interstem tree with
stempiece grafted be-
rootstock and Empire,
Itivar. (The lower
s painted on the stem-
he upper white line
n the scion portion
) The union between
iece and MMlll is 2-
ground. Interstem
d at this depth pro-
ot suckers (shown in
n if most of the stem-
ow ground. Note
meter of the stempiece
an that of the root-
on .
The significant losses of
trees in this planting make most
data meaningless except for overall
observations. Some of the trees
cropped in 1978, particularly the
Empire trees. However, both in
1978 and 1979 yields were much less
than in an adjacent block of Mc-
intosh of the same age on MM106,
M. 7 or M. 26.
Stephen Long-Photo Center
Measurements of the scion and interstem circumferences, tree
height, and tree spread in 1979 indicate that the Empire trees
are larger than those of Millerspur Delicious. The interstem
portion of the trunk is misshapen on some trees (Fig. 2)perhaps
due to the presence of burr knots (adventitious roots which disrupt
the continuity of the bark) . The numbers of burr knots on the
interstem portion vary considerably among trees.
I
i
Fig. 2 . The presence of burr
knots on the M9 stempiece (with
the lower white line in its
center) of interstem trees
disrupts the continuity of the
bark and as shown in the picture
can cause distortion of the
stempiece.
Stephen Long - Photo Center
The data from the 10 states is being summ.arized and will appear
in a future issue of Compact Fruit Tree .
SOIL, TREE, AND FRUIT RESPONSE TO LIME AND TYPE
OF NITROGENOUS FERTILIZER APPLIED AT TWO TIMINGS
UNDER STURDEESPUR DELICIOUS TREES
William J. Lord, John Baker and Richard A. Damon, Jr.
University of Massachusetts, Amherst 01003
A number of fertilizers are used in orchards to supply nitro-
gen (N) . They may contain only an N carrier, or the N carrier may
be mixed with carriers of other elements. N carriers contain
nitrate N, ammonia N, a combination of both, or urea.
Apple trees usually absorb N in the nitrate form because
ammonium N after fixation in the surface soil is rapdily converted
to nitrate N under most soil conditions. However, under some con-
ditions amm.onia N may persist for considerable time. Urea is
rapidly hydrolyzed to ammonia N and then behaves like ammonia.
Nevertheless, apple trees can absorb urea and ammonia N if they
are in solution.
N sources have been compared frequently in apple orchards in
the past. Differential responses have been obtained on acid soils
from N carriers supplying either ammonium or nitrate N because of
slower availability of ammonium N following spring application.
Fixation of ammonia can influence timing of fertilization in irri-
gation water during the growing season, and sodium nitrate could be
harmful on soils with high sodium content. However, these are
unusual situations and it is generally suggested that price per
unit of actual N should determine choice of nitrogenous fertilizer
for orchards.
These studies preceded the concern with low calcium (Ca) levels
in apple fruits and their association with cork spot, bitter pit,
and breakdown of apples. Dr. Shear in 1971 reported that apple
fruits had more severe Ca deficiency symptoms when nytrient-culture-
grown trees received low Ca and 3/4 of their N as NH . , than when
they received all NO3-N. He concluded that the effect of N -source
on the differential movement of Ca into fruit and leaves could be
an important consideration when determining the type of nitrogenous
fertilizer for apple orchards and timing of application. Shear and
Faust suggested that apple growers concerned with low flesh Ca in
apples should not use ammonium N before or soon after bloom because
the absorption of this element may be reduced if ammonium N is present
Calcium nitrate [Ca(N03)2] was suggested as a replacement for
ammonium nitrate by Eggert _et__al . in New Hampshire because it does
not affect soil pH and it supplies a highly water soluble source of
Ca which moves readily into the soil.
To investigate the soil, tree and fruit response to lime, type
of nitrogenous fertilizer, and/or time of application we initiated
an experiment in 1972 with Sturdeespur Delicious trees at the Horti-
cultural Research Center, Belchertown. The trees were planted in a
soil having a pH o£ 6.0 to 6.5 to
half lbs. of high Ca lime (40% Ca
soil in the planting holes for ha
(NH4NO3) , Ca(N03)2 or potassium n
ally from 1972 through 1979 eithe
bloom or at bloom. The trees fer
also received muriate of potash s
amounts of potassium (K) . Herbic
in 1979 in a 3- foot band on each
grass and broadleaf weeds. Paraq
season from 1972 through 1975.
used in mid-May of 1976, 1977, an
pH were obtained within the herbi
1978 and 1979. Below are our res
a 2-foot depth. Two and one-
0; 1% MgO) were mixed with the
If the trees. Ammonium nitrate
itrate (KNO3) was applied annu-
r approximately 1 month before
tilized with NH4NO3 and Ca(N03)2
o all trees received equivalent
ides were applied annually except
side of the tree trunk to suppress
uat was applied twice a growing
Paraquat-plus-simazine was
d 1978. Soil samples to determine
cide-treated strip in 1975, 1977,
ults to date.
Influence of Lime
Incorporating high calcium lime with the soil in the planting
hole significantly increased Ca content of the foliage in 1972 and
1973 but the differences were small (Table 1) . Although the pH of
this soil was high and/or lime was incorporated into the soil, leaf
Ca was still relatively low, further emphasizing the difficulty of
increasing the level of this element in apple trees.
Table 1. The effect of incorporating lime with soil in the planting
hole on leaf calcium (Ca) of Sturdeespur Delicious trees.
Treatment
1972
1973
Leaf Ca {%) :
1974
1975
1976
1977
Lime
No lime
1.08a^
0.79a
0.91a
1.30a
1.07a
0.76a
0.96b
0.74b
0.90a
1.28a
1.05a
0.74a
High Ca lime 2-1/2 lbs. per tree at planting,
Numbers in a column followed by a different letter are significantly
different at odds of 19 to 1.
Influence of N Source of Soil pH
NH4NO3, as expected, increased soil acidity while soil pH
under the trees that received KNO3 or Ca(N03)2 remained fairly
constant (Table 2).
Table 2. The influence on soil pH of three sources of nitrogen
applied annually under Sturdeespur Delicious trees since 1972.
Soil pH under trees receiving:
"Ca(N033 2 NH4NO3 KNO^
Year
soil
sampled
0-6"
depth
6-12"
depth
0-6"
depth
6-12"
depth
0-6"
depth
6-12"
depth
1975
6.16a^
6.09a
5.90b
5.90b
6.18a
6.15a
1977
6.05a
6.03a
5.51b
5.65b
6.20a
6.09a
1978
5.93a
5.85a
5.21b
5.20b
5.99a
5.71a
1979
6.00a
5.92a
5.20b
5.22b
6.14a
6.14a
z
Numbers in a row followed by a different letter are significantly
different at odds of 19 to 1.
In 1979 we also sampled the 20 to 24-inch soil depth and found
the acidifying influence of NH4NO, at these depths but the pH was
higher than at the 12-inch and 6- inch depths (Table 3).
Table 3. Influence of ammonium nitrate and calcium nitrate on soil
pH at different depths, 1979^.
Soil
Soil pH under tree receiving;
depth NH4NO3 Ca(N03)2 KNO3
0-6 5.20b^ 6.00a 6.14a
6-12 5.22b 5.92a 6.14a
20-24 5.57a 6.07a 6.14a
z
Applied annually since 1972
y
Numbers in a column followed by a different letter are significantly
different at odds of 19 to 1.
Influence of N Source on Elements in Leaves
Leaf analyses showed that N and Mg were not influenced by N
source. In 1976 KNO3 increased K and suppressed Ca probably due
to the interaction between these 2 elements. In 1974, 1976 and
1977 the KNO3 trees were lower in foliar Ca than those fertilized
with Ca(N03)2- This is probably an influence of K in KNO3 rather
than an enhancement of Ca by Ca(N03)2 since Ca was not influenced
by NH4NO3.
6.
Fruit Ca levels were analyzed in 1978 and 1979. Fruit Ca
was higher on trees fertilized with Ca(N03)2 on April 12, 1978(93
ppm),than those from trees that received NH4NO3 on May 22, 1978
(84 ppm) , otherwise N source and time of application has not
influenced fruit Ca levels.
Influence of Time of N Application on Elements in Leaves
We suggest that nitrogenous fertilizers be applied as early
as possible in the spring. Among the several things early appli-
cation accomplishes is early absorption of N rather than late ab-
sorption which could cause higher levels of this element at harvest,
reduced red color of fruit, and delayed maturation. However,
our data showed that with the exception of leaf N in 1974, the
level of this element and Ca, K and Mg were similar in mid-July
for the 2 timings of fertilization. The fertilizer application
on April 12, 1974 was followed by 0.7 inches of rain on April 14,
thus it probably was more rapidly dissolved and carried to feeder
root depth than the May 15 application which was followed by 0.3
inches and 1.1 inches of rain on May 24 and June 1, respectively.
Influence of N Source on the Incidence of Bitter Pit
The trees commenced bearing in 1974, but it was 1976 before
cropping was considered sufficiently uniform among trees to exa-
mine the fruits for bitter pit. A frost eliminated the crop in
1977. However, in 1976, 1978 and 1979 N source did not influence
the amount of bitter pit (Table 4) , which gives further evidence
of the lack of differential Ca response to N source.
Table 4. The influence of N source on the incidence of bitter pit
Bitter pit (I):
Nitrogen At harvest At harvest After storage
source 1976 1978 1979 1978 1979
KNO3 lla^ 17a 9a 22a 13a
NH4NO3 8a 14a 6a 18a 9a
Ca(N03)2 7a 16a 6a 21a 11a
z
Numbers in a column followed by a different letter are significantly
different at odds of 19 to 1.
Summary
Mixing lime with the soil used in planting hole for apple
trees enhanced Ca levels for only the first 2 years. Ca(N03)2
and KNO3 are neutral in reaction and have not affected soil pH,
whereas NO4NO3 increased soil acidity, N source or time of appli-
cation had little influence on N, K, Mg , and Ca content of leaves,
no effect on the incidence of bitter pit, and no appreciable influ-
ence on fruit Ca. Thus, it would appear, under the conditions of
this experiment, that no change is needed in the "old idea" that
price per unit of actual N should determine choice of nitrogen
fertilizers for orchards.
HOW ETHEPHON IS BEING USED TO ADVANCE THE MATURITY OF APPLES
IN MASSACHUSETTS
12 2
W. J. Lord , J. Williams and K. Hauschild
Ethephon has been used commercially for several years on early-
maturing cultivars and on Mcintosh to stimulate red color develop-
ment, hasten fruit maturity, and advance the harvest season. We
published a circular with suggestions on the use of ethephon in
1976. The information was up-dated last year and the suggestions
appeared in the July/August, 1979 issue of FRUIT NOTES .
Climatic conditions vary in the state and affect the rate of
ethephon needed to obtain the desired response. Furthermore,
ethephon 's use is influenced by the marketing needs of the grower.
Thus, the purpose of this article is to describe how ethephon is
being used commercially by some growers in Massachusetts.
Horticultural Research Center . Tony Rossi, farm foreman, needs Mc-
intosh apples the first week of September for sale to the University
of Massachusetts dining halls. He applies ethephon at 1 pint, plus
20 ppm 2,4,5-TP, per 100 gallons of water with an air blast sprayer
at IX. Tony uses 2,4,5-TP rather than NAA because it provides bette
pre-harvest drop control and contributes more than NAA for advancing
fruit maturity. The data in Table 1 show the 1974 to 1979 dates of
ethephon application and harvest. Tony selects vigorous young trees
because the fruit are larger and the ethephon effect is greater be-
cause of less shading. Direct sunlight enhances the fruit color res
ponse to ethephon.
It can be noted in Table 1 that the fruit have been harvested
7 to 10 days after the ethephon application. Except in 1979, the
fruit have been harvested in one picking.
r
1
Extension Pomologist
2
Regional Fruit Specialists in Massachusetts
Table 1. Ethephon usage at the Horticultural Research Center
of application and harvest date.
Date
Application date Harvest date
Days from
application to harvest
August 20, 1974
August 27, 1975
August 16, 1976^
August 23, 1977
August 30, 1978^
August 20, 1979
August 29
September 2
August 2 5
September 2
September 7
August 29 and
September 3
9
6
9
10
8
9
14
y
1 pint of ethephon + 20 ppm 2,4,5-TP
Applied earlier than usual because fruit were needed in late August
Application date was delayed because of rain.
Edward Roberts and Sons, Hillside Orchard, Granville . The Roberts'
harvest 10 ,000 to 12,000 bushels of ethephon- treated Mcintosh
apples each fall for immediate sales. Beginning the last week of
August or the first week of September, they apply ethephon to
ferent set of trees every 2 or 3 days, depending upon the wea
a dif-
ther .
In 1979, the first 2 sprays of ethephon were applied at 1/2
pint per 100 gallons of water at IX (Table 2). (However some years
only 1/3 pint of ethephon per 100 gallons of water was used on the
earliest spray dates. The higher rate was used in 1979 in order to
enhance a quicker response.) The next 5 ethephon sprays in 1979 were
applied at 1/3 pint. Sprays applied September 4 or later were applied
at 1/4 pint.
NAA at 10 ppm is used with the ethephon sprays for pre-harvest
drop control. They prefer NAA because it hastens ripening less than
2,4,5-TP.
The ethephon-sprayed fruit are examined twice daily, starting 5
days after spraying, to determine color development . The fruits are
harvested when they obtain 50 to 601 red color , which is generally
6 to 7 days after the ethephon application (Table 2) . (They believe
that by waiting for more color, condition on the retail counter is
sacrificed. )
Table 2. 1979 dates of ethephon application and harvest on Mcintosh
at Hillside Orchards.
Application date Harvest date
Days from
application to harvest
August 2 2
August 24
August 26^
August 2 8^
August 30^
August 31^
September 3^
September 4^
September V
September 9
September 11'
August 2 8
August 29-30
September 1
September 2
September 5
September 6
September 9
September 10
Septem.ber 13
September 16
September 18
6
5
6
6
6
6
6
7
7
1/2 pint ethephon plus 10 ppm NAA
y
1/3 pint ethephon plus 10 ppm NAA
X
1/4 pint ethephon plus 10 ppm NAA
Apples picked September 5 or later are refrigerated, packed within
2 days and shipped within 4 days of harvest.
They have a market for Cortland apples in September. Therefore,
1/3 pint of ethephon plus 10 ppm NAA in 100 gallons of water at IX
is applied on trees of this cultivar the first week of September.
Excellent results have been obtained on young Cortland trees that
produce large fruit.
Atkins Farms, Inc., Amherst . Howard Atkins considers ethephon a good
tool for assisting harvest and permitting sales during harvest.
Ethephon is used on Wealthy, Milton, Mollie's Delicious and other
early maturing cultivars as well as on Mcintosh. When used on early
maturing cultivars, farm manager Stanley Kielbasa has found that the
number of pickings has been reduced from 4 or 5 to 2 . On early culti-
vars ethephon may be applied before first harvest or it may be applied
after the fruit is first "spot-picked", so that the trees can be
"stripped" at the second picking. These early maturing cultivars are
sold at the roadside stand.
10
Table 3. 1979 dates of ethephon application and harvest dates at
Atkins Farm.
Days from
Ethephon application
Cultivar application dates Harvest dates to harvest
Wealthy August 11^ August 25 14
Milton August 18^ September 2 15
Mollie's Delicious August 20^ August 27 7
Mollie's Delicious August 28^ September 5,6 9,10
Mcintosh August 23^ September 7 15
Mcintosh September 5^ September 19 14
z
2/3 pint ethephon plus 20 ppm 2,4,5-TP
y
3/4 pint ethephon plus 20 ppm 2,4,5-TP
Ethephon is applied on Mcintosh blocks scheduled for pick-your-
own or for early sales at both the roadside stand and wholesale.
Dates of ethephon applications and concentrations on Mcintosh and har-
vest dates are shown in Table 3.
Marshall Farms, Fitchburg . Marshall Farms need about 2,000 bushels
of well-colored Mcintosh apples 1 week prior to the normal harvest
period of the Rogers and Hermann strains of this cultivar. Fruit
from trees of their own strain, the Marshall Mcintosh, should ful-
fill this need in the future, but at present it is necessary to apply
ethephon on some Rogers and Hermann Mcintosh trees.
In 1979, the Marshall Farms delayed their ethephon application
until September 4 when cool weather replaced the high temperatures
of late-August and the first 3 days of September. They applied 1/2
pint of ethephon plus 15 ppm 2,4,5-TP per 100 gallons of water with
a Hardy air blast sprayer at IX. The Mcintosh trees sprayed were
14-years-old on M9 , 12-years-old on M7 , and seedling trees over 50
years of age. Alfred Marshall noted that the coloring response to
ethephon was best on the young trees, probably because of better
light penetration. Harvest of the ethephon treated trees commenced
5 days after application.
Marshall Farms in 1979 successfully stored some ethephon treated
Mcintosh in regular storage for 3 to 4 weeks. As a trial they placed
11.
6 bins o£ ethephon- treated Mcintosh in CA storage. These fruit
were harvested September 7, 1979 (5 days after ethephon was applied)
and dipped in 25 pounds CaCl-,/100 gallons of water and placed in CA
storage. The storage was opened in early April and on May 18, 2-1/2
inch apples were pressure tested and had pressure of approximately
14 pounds. Three inch apples were pressure tested on May 19 and had
pressure of approximately 12.5 pounds. Marshall Mcintosh harvested
on September 6 were placed in the same CA storage (untreated) on
the same date. They were pressure tested on May 19, 1979 and 2-1/2
to 2-3/4 inch fruit had pressure of approximately 12.5 pounds.
Marshall Farms produce about 2,000 bushels of Early Mcintosh
for immediate sale from trees ranging in age and size from 14-years-
old on M7 to 20, 25 or 35-year-old trees on seedling roots. Trees
of this cultivar are sprayed annually about 5 to 7 days prior to
normal harvest with 1/4 pint of ethephon plus 10 ppm 2,4,5-TP per
100 gallons of water at IX. This treatment improves red color and
generally reduces the number of times necessary to "spot pick" trees
from 4 to 2.
Bolton Orchards, Bolton . Steve Ware, orchard manager, generally uses
ethephon on Early Mcintosh and Puritan trees to improve red color
and reduce the number of times required for "spot picking". Ethe-
phon is applied at 1/2 pint plus 20 ppm NAA (for drop control) per
100 gallons of water with a Hardy air blast sprayer at IX. The first
group of trees was sprayed on August 1, 1979. Ethephon was applied
at 3 to 4 day intervals to different trees. Enough trees were
sprayed each time to permit harvest of approximately 150 bushels.
Beginning on the 4th day after treatment, Steve observes daily the
color development. The fruit are generally harvested 5 to 7 days
after the ethephon application and are sold at retail to satisfy
early consumer demand.
Wholesale buyers expressed some resistance to purchase of Mc -
intosh apples treated with ethephon in 1978 because of a "dull" Ted
color that Steve Ware described as "not a natural red ".
Carlson Orchards, Harvard . In 1979 Carlson Orchards applied 3/4 pint
of ethephon plus 10 ppm NAA per 100 gallons of water with an air
blast sprayer at IX on 20-year-old Early Mcintosh trees. This spray
was applied at 3-day intervals on a few row of trees. The apples
were harvested 5 to 7 days after the spray application. The trees
were "strip-picked" because the fruits with insufficient color to
meet marketing requirements were used for cider. The remainder of
the Early Mcintosh apples were sold at retail and wholesale.
Authors comments . The Hillside Orchard in Granville is favorably
located for obtaining well-colored Mcintosh. This may partly ex-
plain why they obtain good color enhancement with late-August appli-
cations of 1/2 pint or less ethephon. In our early trials with
12
ethephon at the Horticultural Research Center, it was applied the
1st or 2nd week of September at 1/4 or 1/2 pint per 100 gallons,
with either NAA or 2,4,5-TP for drop control. Even though the appli-
cations were nearer to normal harvest than those applied at the
Hillside Orchard, color did not develop as rapidly. Eight days
after application, only an additional 10 to 20% of the fruit surface
had red coloration.
The growers used either NAA or 2,4,5-TP for drop control on
Mcintosh. Our trials showed that NAA when combined with ethephon
gives effective drop control for 7-10 days. On the other hand,
2,4,5-TP may cause more fruit ripening than NAA, but it does elimin-
ate, in case of a delay in harvest, the chance of excessive fruit
losses due to preharvest drop or the need of a second NAA application.
One grower interviewed expressed concern about possible tree
injury to Mcintosh when using 2,4,5-TP with ethephon. (Injury from
2,4,5-TP is noticeable the year following application. The tips
of terminal shoots in the tops of affected trees appear "naked" be-
cause of injury to lateral buds.) We have not observed tree injury
on Mcintosh at the Horticultural Research Center from 20 ppm 2,4,5-TP.
However, the same rate injured Early Mcintosh and Puritan trees when
it was used with 1/2 pint ethephon to enhance ripening of fruits of
these cultivars. Mcintosh and Delicious trees can be injured by
2,4,5-TP under certain conditions, one of which is over application.
We believe that NAA will generally provide adequate drop control
on early maturing cultivars because the fruits are generally harvested
before drop becomes troublesome. However, if you do use 2,4,5-TP,
10 ppm of this material should be sufficient.
When using 2,4,5-TP for drop control be sure to read the label .
It is available at both IX and 2X concentration and growers have cans
of both concentrations on their shelves.
13.
EXCESSIVE APPLE BUD ABSCISSION IN 1980: WAS IT CAUSED
BY TARNISHED PLANT BUG FEEDING OR COLD TEMPERATURES?
1 2
Ronald J. Prokopy^, Geoffrey L. Kubbell«
William M. Coli , and William J. Lord
At the Horticultural Research Center in Belchertown, as well
as in a number of commercial orchards, we observed an unusual
amount of apple bud abscission this year. The majority of abscissed
buds which we observed never exceeded 1/4 inch in length and turned
dark brown shortly after tight cluster. Some reached 1/2 - 3/4
inch long before abscission occurred, with the calyx cup then turn-
ing yellow. In some cases, all 5-7 buds in a cluster abscissed.
Usually, however, there were at least one or two healthy buds per
cluster.
Our examination of approximately 300 flower bud clusters in
each of 8 commercial orchards revealed an average of 1.6 and 9.2%
abscissed buds in 1978 and 1979, respectively. This year, an aver-
age of 18.11 of the buds in these same 8 orhcards was abscissed,
with one orchard reaching 36.71 abscission. Our sample consisted
almost exclusively of 'Mcintosh' and 'Red Delicious' trees, with
the level of abscission about the same on each. Abscission levels
appeared to be greater on 'Cortlands', although we sampled few trees
of this cultivar. This observation is in agreement with bloom data
obtained from other experiments involving these cultivars.
In an earlier study (FRUIT NOTES 42(2): 10-14, 1977), we showed
that feeding by tarnished plant bug (TPB) adults on apple flower buds
from the silver tip up to the tight cluster stage could result in
substantial bud abscission. The large number of TPB adults captured
on our white monitoring traps from silver tip to tight cluster in
commercial orchards this year suggested to us that TPB adults may
have been principally responsible for the high level of bud abscission.
At our research block at the Horticultural Research Center, we
had placed cages over several hundred dormant buds in early April
to prevent entry of TPB and other insects. Abscission of uncaged
buds on these trees was high (68%) , but it was nearly as great (54%)
for the caged buds. The large number of TPB adults (7.2/trap by
tight cluster) in this block may have accounted for most or all of
the 14% difference here, but these adults obviously were not the
principal cause of bud abscission.
1
Extension Entomologist
2
Research Technician
3
Pest Manager Specialist, Entomology
4
Extension Pomologist
14
We therefore believe that the majority of bud abscission in
commercial orchards this year was caused by low temperatures. It
is possible that the rather high temperatures from April 11-15
(590-68° F) followed by the low temperatures on April 16 (24° F) ,
may have been the responsible factor. It is too soon to tell if
the size of the 1980 fruit crop will be affected by this abnormally
high level of bud abscission.
Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
James B. Kring
Acting 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
(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. 45 No. 5
SEPTEMBER/OCTOBER 1980
Table o£ Contents
Progress Report: Pruning Effects
on Tree Growth and Fruiting
of Spartan Apple
Do Calcium Chloride Sprays Affect
Apple Maggot Fly Egglaying?
Causes of Defects on Mcintosh
Apples at Packing Sheds and
Their Effects on Returns
Controlling Orchard Mice
PROGRESS REPORT: PRUNING EFFECTS ON TREE GROWTH
AND FRUITING OF SPARTAN APPLE
William J. Lord and Joseph Sincuk
Department o£ Plant and Soil Sciences
Small trees on size-controlling rootsto
omically pruned, sprayed, and harvested than
ling rootstocks. Nevertheless, training and
comes increasingly important as planting den
the past, we had low density orchards with s
seedling rootstocks which performed well on
types and there was little concern about tre
We now have low, medium and high density ore
and each type requires somewhat different tr
cedures. The trees are spur-type, standard-
and tree vigor varies considerably especiall
rootstocks because of soil types. In spite
trees, some growers report that pruning hour
creased rather than decreased. Therefore, i
several long-term trials to compare pruning
in the past. Below is a summary to date of
on tree growth and fruiting of Spartan apple
cks can be more econ-
large trees on seed-
pruning of trees be-
sity increases. In
tandard-type trees on
a wide range of soil
e height and spread,
hards in Massachusetts
aining and pruning pro-
type or interstems,
y on weaker growing
of the trend to smaller
s per acre have in-
n 1976 we initiated
systems with those used
a study of pruning effects
trees .
The Spartan apple trees on M. 7 rootstock were plante
Horticultural Research Center, Belchertown, }AA in 1975.
1976, we established the following pruning programs: (A)
suggested by Dr. D.R. Heinicke in USDA Agriculture Handbo
(Figures IB, 2), hereafter referred to as the USDA system
in tiers and central 1
annually, hereafter re
as the tier system (Fi
(C) minimum of pruning
zagging' the central 1
ure 4) , hereafter refe
the slender spindle sy
(D) pruning as done in
(Figure lA) , hereafter
to as regular pruning,
trees have been pruned
method .
d at the
In February,
a program
ok No. 458
; (B) limbs
eader headed
ferred to
gure 3) ;
and 'zig-
eader (Fig-
rred to as
stem; and
the past
referred
Twelve
by each
Fig. 1A.
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. IB.
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.
Pruning and Training Methods
USDA System . The system involved heading cuts and developing
limbs m tiers (Figure 2).
MOW TO GET THE HIGH DENSITY TREE OFF TO A GOOD STA«T
HEAVY MA«KS SHOW WHERE PRUNING CUTS SHOULD BE MADE.
I -yaOf'Old ttctton
compiling ihooll
minol ihoof
R«mov« all
Heod bock Hr-
2 y«ar-old t«(hon Select and
h*od lateral bronchei Remove
unneceiiory loteroU
3-reor-otd tection Spfeod bronch-
ei, remove forked termmalt *o o
lingle thoot and heod IKot moot.
Head fide ihooti
4 year old tcctton Spreod branch-
e», remove foried termlnall lo o
lingle iheel and head H^al ihool
Heod tide ihootf
S-yeor old leciion and older If
tree hot filled oHoned ipoce,
head back where neceitory into
2 yeor-old wood to on unheeded
tide ihoot Avoid heading cut»
Into 1 -yeor-old thoott until the
tree It fruiting well
Fig. 2. A diagram of the "constructive training" program suggested by Dr. D.R. Heinicke in USDA Agriculture Handboc
No. 458 entitled "High Density Apple Orchards— Planning, Training and Pruning." (Reproduced with permission i
the author.)
The central leader and each 1-year-old shoot on scaffold limbs were
headed during dormant pruning by removing 1/4 to 1/2 of the past
season's growth. The central leader was headed to induce branching
so that a tier of scaffold limbs could be developed 24 inches above
a lower tier of limbs. The heading cuts on shoots ' originating from
scaffold limbs were made to encourage developm.ent of lateral shoots
to increase fruiting potential.
In May of each year, 2 or 3 vigorous shoots developed from the
buds directly behind the heading cut on the central leader and later-
al shoots. When shoot growth was 4 to 6 inches long, one shoot on
each central leader and each headed lateral shoot was selected as
the permanent extension shoot and competitors were removed. Limb
spreaders were used when needed.
Tier System . Pruning and training procedures were similar to those
for the USDA systemexcept that none of the 1-year-old shoots on
scaffold limbs were headed.
Slender-spindle System . All the scaffold branches 18 inches above
ground level were kept except for those with narrow crotch angles.
Frequently, 2 or more branches of approximately the same size
originated adjacent to each other. These whorls of branches
were not eliminated until their presence appeared to be suppress-
ing the dominance of the leader. At this time, one branch in
the whorl was retained and the others were removed at their point
of origin on the central leader.
Figure 3. A 4-year-old Spartan/7A
being trained with limbs in tiers,
The paint, except on' the trunk,
marks where heading cuts were
made on the leader. Photographed
March, 1979.
Figure 4. A 4-year-old
Spartan/7A being trained
as slender spindle. Tree
has received a minimum
of pruning. The leader
has been pruned to an up-
ward growing lateral
branch in attempt to
zig-zag the leader. Photo-
graphed March, 1979.
The procedure of removing the strong vertical leader during
dormant pruning and using a weak competitor as the new leader was
was not successful because it became apparent that the dominance of
the leader was difficult to maintain. Thus, it became necessary in
most instances to establish a dominant leader and delay, until dor-
mant pruning in 1979, the procedure of using a weak competitor as
the new leader (Figure 4). Limb spreaders were used when needed.
Regular type Pruning . This system involved selection o£ branches
symmetrically arranged around the vertical axis of the tree and
spaced far enough apart to avoid limb crowding when the trees be-
came larger. Less temporary branches were left to provide addi-
tional leaf surface than on the slender spindle trees. Whorls of
branches were eliminated in order to allow only one branch to
develop at a given level. The dominance of the central leader was
maintained by suppressing or removing competing leaders.
Results and Discussion
USDA System. We found
having
summer .
trees -
Tier tr
minutes
was not
heading
by the
trees b
to make heading
In March, 197
2.2 5 minutes;
ees - 0,91 minu
The time req
recorded. Mos
cuts on the US
regular system.
ut most time co
the US
cuts a
9, prun
(b) Reg
tes ; an
uired t
t time
DA tree
Few c
nsuming
DA system to be time consuming due to
nd remove competitor shoots during the
ing time per tree was: (a) USDA
ular-type trees - 1.66 minutes; (c)
d (d) slender spindle trees - 0.66
o summer prune the USDA and tier trees
consuming during dormant pruning were
s and pruning decisions on those pruned
uts were made on the slender-spindle
was pruning decisions.
The heading cuts during dormant pruning followed by removal of
competitor shoots in late May failed to encourage growth behind the
area of removal in 1976 and 1977. However, in 1978 and 1979 lateral
shoots behind the heading cuts were longer on the headed than on
the non-headed 1-year-old shoots on scaffold branches (Table 1) ,
but the response was much less than that shown in photographs in
USDA Agriculture Handbook No. 458. This can be noted when compar-
ing branching on the tree shown in Figure 5 with that shown in Figure
6.
Table 1. Current season lateral shoot growth on headed and non-
headed 1-year-old shoots of Spartan apple trees^.
Type of pruning on
1-year-old shoots
on scaffold lii±)S
Mean length of current
season lateral shoots on
1 -year- old wood (cm)
Current season lateral
shoots longer than 4 cm
on 1-year-old wood (%)
1978
1979
1978
1979
Heading cuts
USDA system
No heading cuts
Slender- spindle trees
Regular-pruned trees
Trees with linijs in
tiers
5.4a^
3.3b
3.7b
3.3b
5.3a
2.3b
2.0b
1.8b
32a
lib
16b
14b
26a
10b
6b
5b
Trees planted in 1975.
Means in columns not having letters in common are significantly at odds of 19 to 1,
5.
Therefore, heading cuts do not appear worthwhile on these vigorous
Spartan trees which produce adequate lateral branching because of
their standard- type growth habit.
At the end of the 5th growing season
trees had 3 tiers of branches spaced about
5 branches per tier (Figure 5) .
in 1979 the USDA-system
2 feet apart with 4 or
Figure 5. A Spartan tree
on which 1-year-old
shoots on scaffold limbs
were headed during the
dormant seasons of 1976
through 1979. This tree
in comparison to the tree
shown in Figure 6 has
more lateral branches. The
paint, except on the trunk,
marks where heading cuts
were made on the leader
and 1-year-old shoots.
Photographed May, 1980.
Figure 5
When the tiers were formed, 6 or 7 limbs were retained because
the extra limbs provided leaf surface and permitted a choice
when selecting permanent limbs. When the extra limbs were removed,
limb selection was made to maximize the vertical spacing of the
permanent limbs. The extension growth from the headed leaders
was longer than that on the non-headed leaders in 1976 and 1978
but not in 1977 (Table 2.) The extension growth of the central
leaders was not measured in 1979.
Figure 6. A tree on which no heading cuts were made on 1-year-old
shoots. Photographed May, 1980.
The USDA system trees, in comparison to the slender spindle
trees, made less trunk circumference increase in 1976 and 1977
(Table 2) . In 1978 trunk circumference increase was similar for
the 4 pruning treatments probably because cropping restricted
vegetative growth on the slender spindle and regularly pruned trees
(Table 2). The influence of cropping on trunk circumference in-
crease also was evident in 1979.
Table 2. The response of Spartan trees to pruning systems initiated
in 1976 at the Horticultural Research Center, Belchertown, MA^ .
Year
response
measured
Pruning system
USDA
Slender spindle
Regular
Tiers
1976
1977
1978
1976
1977
1978
1979
Length of extension growth of central leader (cm)
y
103a-
98a
67a
4.3b
4.3bc
5.0a
4.6a
5.6a
5.0a
5.1a
3.9b
76b
99a
90a
97a
51b
63a
Lcrease (cm)
4.8b
4.3b
4.6ab
4.2c
5.0a
5.0a
4.3ab
3.8b
Yield (bushels)
1978
1979
0.00b
0.32b
0.12a
1.32a
0.09a
1.02a
0.02b
1.38a
Trees planted in 1975.
r
Means in rows not having letters in common are significantly different at odds
of 19 to 1.
Yields v;ere higher in 1978 on the less - severely pruned slender
spindle trees and regular pruned trees than on the USDA and tier trees
In 1979, yields were higher on the slender spindle, regular and tier
trees than on the USDA trees.
The heading cuts on 1-year-old shoots of the USDA trees removed
growth on which fruit spurs would have developed. Furthermore,
measurements in 1979 indicated that the average distance of the first
blossom cluster from the tip of shoots produced in 1977 was 10 cm
on headed-wood in comparison to 2 cm on non-headed wood. This in-
dicates that the buds directly behind the heading cuts, made in Feb-
ruary, 1978 remained vegetative during the growing season of 1978
instead of producing flower buds. This appears to explain why
the USDA trees were less productive than the tier trees in 1979.
Trees with limbs in tiers . Trees pruned by this system responded
similarly to the USDA trees in regard to growth in 1976, 1977
and 1978 and to yield in 1978 (Table 2). However, these trees
were more productive than the USDA trees in 1979 and trunk cir-
cumference increase was less. Pruning time has been less because
no heading cuts were made on 1-year-old branches on scaffold
limbs .
Slender spindle trees . Pruning of the slender spindle trees has
been the least time consuming of the 4 systems. The trees, based
on trunk circumference increase, produced more growth than the
heavily pruned USDA and tier trees in 1976 and 1977 and more fruit
in 1978 (Table 2). In 1979 yield on the slender spindle trees was
higher than on the USDA tree.
It is well known that non-pruned trees are larger and more
productive than pruned trees. The slender spindle trees are a
compromise. The trees have been lightly pruned leaving as many
branches as possible without stunting the growth of the central
leader .
Regular-type pruning . The pruning system has been somewhat more
time consuming than on the slender spindle trees but less than that
for the USDA trees. Yields of the slender spindle and regular-
pruned trees were comparable in 1978 and 1979 (Table 2),
Summ^ary
The USDA pruning system has been more time consuming than the
tier system, slender spindle system, or regular pruning and reduced
yields in 1978 and 1979. Heading cuts caused some lateral shoot
development on 1-year-old wood but much less than shown in USDA
Agriculture Handbook No. 458 following similar pruning.
At present we prefer the slender spindle system which involves
leaving as many branches as possible without stunting the growth
of the central leader.
Recommendations
At present we will continue to suggest the following for non-
bearing trees of standard- type strains: (a) prune as little as
possible without dwarfing the central leader; (b) make heading cuts
only when necessary to stiffen the central leader or scaffold bran-
ches, or to stimulate growth; and (c) spread branches when necessary
9.
DO CALCIUM CHLORIDE SPRAYS AFFECT APPLE MAGGOT FLY EGGLAYING?
1 2 ^
Ronald J. Prokopy , Sylvia S. Cooley , Bonnie L. IVeeks^, and
Anne L. Averill
Department of Entomology
In an earlier issue o£ FRUIT NOTES (Vol. 42, No. 1), we des-
cribed how, after laying an egg, an apple maggot female drags its
ovipositor on the fruit surface. In so doing, the female releases
a substance (called a pheromone) which deters other females from
attempting to lay an egg in that fruit.
For the past three years, in cooperation with chemists from the
USDA Lab in Gainesville, Florida and neurophysiologists from the
Department of Zoology at the University of Massachusetts, we have
been working on the chemical identity of this pheromone and on
various physiological, behavioral, and ecological aspects of the
pheromone deterrent system in the flies. Our eventual aim is to
apply synthetic pheromone in sprays to prevent maggot fly egglaying.
In the course of recent laboratory studies, we found that apple
maggot fly egglaying is deterred not only by the pheromone but also
by sodium chloride (table salt). As shown in Table 1, sodium chlor-
ide at concentrations of 2 and 9 pounds per 100 gallons gave about
the same moderately-strong levels of egglaying deterrence as 2 and
3 ovipositor dragging equivalents (ODE) of pheromone laid down by
the flies (1 ODE = amount of pheromone deposited after laying 1 egg) .
Apparently the flies do not like to lay eggs in fruit treated with
table salt any more than they like to lay eggs in fruit treated with
pheromone.
Table 1. Percent arriving females attempting egglaying into hawthorn
fruits treated with different concentrations of pheromone, sodium
chloride, and calcium chloride (ODE = ovipositor dragging equivalent),
Attempting Attempting Attempting
egglaying Sodium egglaying Calcium egglaying
Pheromone [%) chloride (%) chloride (%)
Clean check 77 Clean check 79 Clean check 86
2 ODE 50* 2 lbs/100 gal 49* 3 lbs/100 gal 68
3 ODE 28* 9 lbs/100 gal 35* 7 lbs/100 gal 83
Significantly less than egglaying in clean check fruit
Extension Entomologist
2
Extension Technicians
3
Graduate student. Entomology
10
These results suggestedthat calcium chloride sprays applied
to apple trees in July and August (maggot fly season) to increase
calcium in the fruit might possibly act like sodium chloride salt
sprays, and deter egglaying of apple maggot flies. However, the
data in Table 1 shows that at the recommended rates of 3 pounds per
100 gallons, and even at double that rate (7 pounds per 100 gallons)
calcium chloride sprays have no discernible deterrent effect on
maggot fly egglaying. Apparently the flies' contact chemical
receptors (located on the bottom of their feet) respond differently
to calcium compared with sodium salts.
Thus, to their advantage, the flies are not put off by the
type of salt we offer them in our orchards.
**********
CAUSES OF DEFECTS ON MCINTOSH APPLES AT PACKING SHEDS
AND THEIR EFFECTS ON RETURNS
Henry M. Bahn
Department of Food and Resource Economics
and 2
Glenn Morin
Department of Entomology
Last year we summarized in FRUIT NOTES (Volume 44, No. 5) our
evaluation of labor productivity in grading and packing Mcintosh
apples grown under integrated pest management conditions in 1978.
It was suggested that during the 1979-1980 storage season we in-
spect Mcintosh apples at packing sheds in Massachusetts to deter-
mine why they failed to meet grade requirements for US Fancy fruit
and analyze the effect of defects on returns. The results of
this study are presented below.
Experimental Procedures
Culled Mcintosh apples at 10 packing sheds were examined dur-
ing the period from November, 1979 through January, 1980 to deter-
mine the reasons for rejection. At least one-half day was spent
at each packing shed which, with one exception, were all manual
sorting, sizing, and packing operations. A total of 1431 bushels
were packed and 315 bushels were culled.
1
Extension Specialist in Farm Management
2
Senior Pest Management Field Scout
11
The culls were inspected to determine the reason for re-
jection. Only the first or most obvious defect observed was
listed as the reason for culling. Thus, fruit with multiple
defects were not double counted and the additional defects were
not recorded. This procedure was used to duplicate as closely
as possible the normal grading method. The packer/grader is
interested primarily in removing defective fruit from the line
rather than determining the specific type of defect. The first
or most obvious defect is, therefore, the critical one. All
culled apples were inspected by the same individual.
During inspection of the culls, defects were noted and
later categorized by type. Each category was expressed as a
percentage of total culls and as a percentage of total apples
graded .
Results
Defects on stored apples . The fruit sampled had a cull rate aver-
aging 22.2 percent (Table 1). Cullage ranged from 3.3 percent to
53.4 percent. This large variation may be partly explained by
the fact that the samples included first, second and strip pickings
Table 1. Reasons why Mcintosh apples were below grade at grower
packing sheds, 1979
Bushels Percentage of Percentage of total
of culls showing apples culled because
Grade defects culls this defect of this defect
Misshapen 3.0 1.0 0.2
Insect damage 5.7 1.8 0.4
Disease damage 7.0 2.2 0.5
Russeting 18.5 5.7 1.3
Bruise 25.5 8.1 1.8
Mechanical^ 25.5 8.1 1.8
Stem puncture 31.2 9.9 2.2
Color (< US No.l) 53.0 16.9 3.7
Size (< 2-1/4") 145.0 46.0 10.3
Other 0.6 0.3 —
Totals 315.0 100.0 22.2
Includes limb rub , cuts , and cracks
12.
Size and color defects account for 46 and 16.9 percent,
respectively, of all culls (10.3 and 3.7 percent of total fruit
graded). Reducing size and color defects is no easy task. Fol-
lowing proper cultural practices is imperative, with particular
emphasis on pruning, thinning and proper fertilization. Beyond
cultural practices, however, both of these categories are highly
dependent on local growing and climatic conditions. They are,
therefore, to some degree beyond the grower's control. Less than
ideal growing periods during some portion of the 1979 grooving sea-
son may have made the number of size and color defects dispro-
portionately large in this study. An additional study should be
undertaken to determine the "normal" distribution of defects.
Physical damage (bruise, mechanical and stem puncture) re-
present over 26 percent of the culled fruit and 5.8 percent of
the total graded. Being a soft fleshed fruit, Mcintosh apples
are more susceptible to damage during harvest, handling and pack-
ing than most other varieties. For example, a Mcintosh apple
dropped three inches onto a flat board surface will develop a
bruise of about 7/8" diameter. This defect will downgrade apples
to as low as U.S. Utility.
Physical damage is an area in which cull rates could be re-
duced and is thus worthy of the grower's attention. Using extra
care when removing fruit from the tree, dumping picking buckets,
during handling from the tree to the storage, and packing could
reduce these injuries. It could be worthwhile to monitor closely
the handling of fruit to determine when and how the damage occurs.
One study showed that 17 percent of the apples harvested were
severely bruised (bruises larger than 3/4" in diameter) by an
experienced picker. Whereas only 4 to 6 percent of the fruits
were severely bruised by other experienced pickers in the same
harvest crew. Such a level of damage should be unacceptable to
the grower.
Pest and disease are two areas in which fruit growers use a
variety of control measures. Defects in these categories account
for only 4 percent of the culled fruit and less than 1 percent of
all apples handled. These low damage levels are indicative of the
importance growers place on controlling insects and disease in the
orchard. The low levels are also a measure of the effectiveness
of the research and development of preventive technology.
Economic implications of defects . All damaged or defective fruit
represents a loss of revenue to the grower. This loss can be
expressed as the difference between the value of the fruit if un-
damaged (Fancy or Extra Fancy) and the cull (cider) value. The
information, presented in Table 2, was developed using an estimated
yield of 600 bushels per acre, an average value of $10.50 per bushel
for undamaged fruit and a value of $2.50 per bushel for culls.
13,
The loss in revenue can be thought of as the "cost" of the
defect. By being aware of this cost, the grower is in a position
to assess the net value of taking some additional preventive action,
Suppose, for example, most physical damage is found to occur when
fruit is dumped from picking buckets into bulk bins. An estimate
of the lost revenue due to the rough handling can be made. The
grower can then determine if the cost of a little more time and
effort to reduce handling damage is exceeded by the increase in
returns .
2 gives an indication of those areas which cost the
most in terms of lost revenue. Size and color defic-
iencies together account for a loss in revenue of $672 per acre
($494 for size and $177.60 for color). Fruit culled because of
Table
grov/er the
physical damage represents a loss of $287,40 per acre ($86.40
each for bruise and mechanical damage and $105.60 for stem, pu
ture) .
unc-
Table 2. Revenue loss on cull Mcintosh apples at grower packing
sheds, 1979.
Grade defect
Percent of
total apples
culled because
of this defect
Culls per
acre with
this defect
Value of
culls if
not
damaged'^
Cull
value
Loss of
revenue
due to
this defect
bushels
$
$
$
Misshapen
0.2
1.2
12.60
3.00
9.60
Insect damage
0.4
2.4
25.20
6.00
19.20
Disease damage
0.5
3.0
31.50
7.50
24.00
Russeting
1.3
7.8
81.90
19.50
62.40
Bruise
1.8
10.8
113.40
27.00
86.40
Mechanical
1.8
10.8
113.40
27.00
86.40
Skin puncture
2.2
13.2
138.60
33.00
105.60
Color (<US No.
1)
3.7
22.2
233.10
55.50
177.60
Size (C2-1/4")
10.3
61.8
648.90
154.50
494.40
Totals 22.2
133.2
1
1398.60
333.00
1065.60
Yield, 600 bushels per acre
At $10. 50 per bushel.
At $2. 50 per bushel
w
Column 4 minus column 5
14.
For insect and disease damage, the revenue loss per acre is
a relatively low $43.20. This includes $19.20 for insect damage
and $24 for disease. The cost of reducing these injury levels any
further may be nearly as great as the value of the fruit saved.
This again is an indication of the grower's success in dealing with
pests and disease.
Note that a 10 percent reduction in physical damage would mean
additional revenue of $27.84 per acre. This would more than off-
set the loss due to either insect or disease damage. Such a re-
duction may be nearly cost free if it could be accomplished by
handling the apples just a bit more carefully.
Summary and Conclusions
The packing operations sampled had a combined cull rate of
22.2 percent. Assuming a 600 bushel per acre yield, the culls
mean a reduction in revenue of $1065.60 per acre. Note that at
higher yields, the loss of revenue would be even larger.
The challenge to the grower is clear: by reducing cull rates,
revenue per acre can be increased. Given the high cost of equip-
ment, materials and labor, however, the cost of reducing some types
of damage such as insect and disease may nearly equal the revenue
gained.
Bruise, mechanical and puncture defects m.ight be reduced with-
out increasing costs too much if the grower is careful to determine
where and when the damage occurs. Although speed is important when
picking, grading and packing, the labor force should be reminded
that they are dealing with a very fragile apple and that some extra
care is necessary. Likewise forklift, tractor and truck drivers
should be cautious when handling the apples. A 6 inch drop can
cause considerable bruise and puncture damage to the contents of a
box or bin.
Good cultural and pest control practices have reduced insect
and disease damage to acceptable levels. Similar attention to de-
tail in labor management and handling may go a long way toward re-
ducing physical damage.
The large revenue losses due to size and color defects and
physical damage have some research and Extension implications as
well. More attention should be given to practices that can reduce
fruit size and color deficiencies. Harvesting and handling pro-
cedures and both hand and mechanical grading and packing methods
should be scrutinized to determine which result in the lowest
damage levels.
15.
CONTROLLING ORCHARD MICE
Edward R. Ladd, Wildlife Biologist
U.S. Fish and Wildlife Service
Unless preventive measures are taken, orchardists can expect
mouse damage to fruit trees during the winter months. Most fruit
growers know from past experience which areas or blocks of trees
are likely to be damaged. Still, it is a good idea to check the
orchard in the fall to determine the status of old problems, and
if any new trouble areas have developed. Areas having clean mouse
trails, chewed apples, or the characteristic fan-shaped mounds
of soil, pushed up by pine mice, are indicative of potential mouse
damage problems. The amount of these indicators found will deter-
mine if greater than normal mouse control is necessary.
Meadow Mice
These are the surface- living mice most common to orchards in
the Northeast. They injure fruit trees by chewing bark from the
root collar upward. Since these mice, like all animals, require
food and shelter for survival, some protection can be gained by
close mowing of the vegetation in the orchard. Control of grass
and weeds in the orchard should be done periodically throughout
the year, but especially in the fall. Close mowing removes cover
and makes the area less acceptable to mice. Any reduction in cover
should help prevent damage prior to snowfall.
Control of vegetation should not be used as the primary mea-
dow mouse control method in the fall, but merely as a supplement
to the use of toxic baits. Remember that during the winter deep
snow will provide the needed cover for mice and they will be able
to reach the trees without exposing themselves.
The best method for controlling orchard mice is still the proper
application of mouse control baits. All sections of the orchard hav-
ing meadow mice should be treated in the fall following apple har-
vest. Those areas having an overabundance of mice will need an ex-
tra treatment, if for some reason the initial one does not give
adequate control. If mouse concentration sites with wood, roofing
squares or other materials are used, they make excellent areas to
check on mouse activity in addition to their bait exposure use.
In addition to regular mouse control within the orchard, the
mowing and baiting of buffer areas is still recommended. This is
particularly true if fall orchard checks show high mouse activity.
These treated buffer strips should help reduce mouse migration into
16.
the orchard during the winter months.
Periodic checks during the winter months, particularly after
a thaw, may reveal spots still having meadow mouse infestations.
A few tablespoonfuls of mouse bait, poured into the holes, may
give added protection for the remaining winter m.onths.
Pine Mice
Pine mice are an underground species found in many orchards
in the Northeast. Their location in the orchard may be restricted
to a portion of a tree block or to a single tree. These mice
damage apple trees by girdling the root system. This form of
injury may not be readily apparent until the tree loses its vigor,
the leaves take on a yellow cast, or sprouts appear from the damaged
roots .
Control of pine mice is more difficult and seldom as effective
as for meadow mice. The broadcast method of distributing poisoned
baits recommended for meadow mice may be only partially success-
ful in controlling this species. It should be noted that control
of vegetation may not have any effect on pine mice because of
their subterranean living habits.
To obtain good control, orchard mouse baits should be placed
in underground trails where the animals spend most of their time.
If the infested area is small, hand baiting of the pine mouse
natural runways is effective.
For larger areas, the use of the Trial Builder Machine is
an advantage if soil and sod conditions permit. Be sure the machine
is aligned properly and is making a good tunnel through the sod.
Artificial trails on at least 2 sides of each tree are required for
adequate coverage.
Whether an orchardist hand baits for pine mice or uses a
machine, there is one absolute necessity: the artificial trail and
the natural runs must be kept as clean as possible . Pine mice
maintain clean, well-packed trails. They remove all foreign matter
and debris, especially soil, from the tunnel. In the process, mice
quite often will cover or carry out the treated bait with other
materials .
NOTE : As in previous years, a permit for bait application must
be obtained from the Massachusetts Division of Fisheries and Wild-
life, 100 Cambridge Street, Boston, Massachusetts 02202, before any
orchard mouse control can be done using toxic baits.
Cooperative Extension Service
University of Massachusetts
Amherst, Massachusetts
James B. Kring
Acting 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. 45 No. 6
NOVEMBER/ DECEMBER 1980
TABLE OF CONTENTS
Evaluation of Several Pear Psylia Control Programs in
Connecticut
Orchard Practices Necessary for Good Peach
Production
Notice of New England Fruit Meeting
Integrated Management of Apple Pests in Massachu-
setts 1980 Results: Insects
FRUIT NOTES INDEX FOR 1980
EVALUATION OF SEVERAL PEAR PSYLLA CONTROL
PROGRAMS IN CONNECTICUT
Roger G. Adams and David A. Kollas
Plant Science Department
University of Connecticut
Storrs
The adult pear psylla is dark reddish-brown, about 1/10 inch
long, and looks like a miniature cicada. They overwinter under
the bark of pear trees and in other sheltered areas. Yellow,
rice- grain shaped eggs are first deposited on fruit spurs, but as
the buds open eggs are laid on exposed leaf tissue. There are
five instars or nymphal stages. The first four instars feed on
plant sap and excrete a drop of clear colored, sticky honeydew
liquid around their bodies. The fifth instar is not surrounded with
honeydew and is called the "hardshell" stage. It is dark brown
with prominent wing pads. The earlier instars range in color
from yellow to greenish-brown. About one month is required to
complete the life cycle. There are several generations each year.
The pear psylla was first reported in the United States from
Connecticut in 1S32. Since that time it has become the most im-
portant insect pest of pears in North America.
The pear psylla has become resistant to many form.erly effective
insecticides, thus making control increasingly difficult.
Five treatment programs and a check were evaluated in 1979 for
the control of the pear psylla on 18- year- old Bartlett pears at the
University of Connecticut Spring Hill Orchard in Storrs. The treat-
ment programs, dosage rates, and dates of application are presented
in Table 1 on the following page. All insecticide treatments were
applied as dilute sprays by handgun. Five, single-tree replicates
were used per treatment.
To sample for eggs and nymphs, 4 spurs per tree (one from each
quadrant) were collected and brought back to the lab where pear
psyllas were counted with the aid of a microscope. Adults were
sampled by tapping limbs with a rubber covered piece of wood and
recording the number of adults falling onto an 18 by 18 inch cloth-
covered frame. One tap per limb was used from four locations per
tree. On July 27, 1979 tree limbs and leaves were visually examined
and rated for the presence of honeydew and sooty mold. The following
damage index scale was used: = clean; 1 to 2 = light; 3 to 4 = mod-
erate; 5 to 6 = heavy. Percent clean fruit was determined by examin-
ing 20 fruits per tree.
Table 1. Schedule of insecticide treatments for the control of
pear psylla on pears. Spring Hill Orchard, CT. 1979.
ab
Treatment programs Dosage/100 gals. Dates applied
A. Superior oil 3 gals. 4/12, 4/23,5/18,
6/15, 6/29
B. Superior oil pre-bloom; 3 gals.
fenvalerate 2.4EC 10.7 fl. oz. 4/12, 4/23,
(Pydrin) starting at 5/3, 5/18
white bud stage
C. Superior oil pre-bloom; 3 gals. 4/12, 4/23,5/3,
phosalone SEC (Zolone) 1.7 pts. 5/18, 6/4, 6/15,
starting at white bud 6/29
stage
D. Fenvalerate 2.4EC 10.7 f 1 . ozs. 5/3, 5/18
(Pydrin)
E. Superior oil pre-bloom; 3 gals. 4/12, 4/23, 5/18
fenvalerate 2.4EC (Pydrin) 10.7 f 1 . ozs.
starting at petal fall
P. Check (untreated)
a
All treatments, with the exception of the check (F) received one
application of az inphosmethyl (Guthion) on 5/18 at the rate of
10 ozs./lOO gals., and one application of amitraz (BAAM) on 7/31
at the rate of 2 pts./lOO gals.
b
All insecticides applied dilute to runoff by handgun.
Damage ratings are presented in Table 2. Percent clean fruit
was highest (94, 94 and 92%) in treatment programs using fenvalerate
(Pydrin) either alone (Treatment Program D) or in conjunction with
pre-bloom oil treatments (B and E) . Oil used alone (A) or in con-
junction with phosalone (Zolone) (C) resulted in 75 and 88% clean
fruit, respectively. Few (61) clean fruits were found on check
trees (F) . Limb and leaf contamination ratings corresponded well
with the percent clean fruit findings.
Table 2. Effect of various pear psylla control programs on honeydew
and sooty mold on pears. Spring Hill Orchard, Storrs, CT . 1979.
Honeydew and sooty mold ratings
a b
Treatment programs Limb and leaf Clean fruit (I)
A. Superior oil 3.0 75
B. Superior oil pre-bloom; 1.0 94
fenvalerate 2.4EC (Pydrin)
starting at white bud stage
C. Superior oil pre-bloom; 2.4 88
phosalone 3EC (Zolone)
starting at white bud stage
D. Fenvalerate 2.4EC (Pydrin) 1.0 94
E. Superior oil pre-bloom; 1.8 92
fenvalerate 2.4EC (Pydrin)
starting at petal fall
F. Check (untreated) 5.6 6
a
The following damage index was used: = clean; 1 to 2 = light;
3 to 4 = moderate; 5 to 6 = heavy.
b
Based on 100 fruits per treatment.
Figure 1 on the following page shows the seasonal history of
pear psylla populations for insecticide treatment programs A-E and
the check (F) .
Programs utilizing 1-2 sprays of fenvalerate (Pydrin) (B, D, and
E) were the most effective in managing pear psylla and minimizing
damage. In these treatments, nymph and adult numbers averaged about
one or less per spur or limb tap from early May through late June.
In all other treatments, at least one of the developmental stages of
psylla exceeded this level. Phosalone (Zolone) (C) was moderately
effective but required 5 sprays and resulted in somewhat greater
damage than the fenvalerate (Pydrin) treatments. Oil used alone (A)
did not give acceptable control.
Nymph populations in treatments A and F declined more slowly
and resurged sooner than in other treatments. Egg numbers also
resurged more rapidly on trees in treatments A, C and F. These
differences in population decline and resurgence rates may also have
contributed to differences in damage ratings among the treatments.
100
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5.
Adult populations in early spring were lowest on treatments
which received oil (A, B, C and E) . Zwick and Westigard (1978) in
Oregon reported a delay and a reduction in egg laying by overwinter-
ing pear psylla adults attributable to the use o£ petroleum oils.
We observed a similar delay in egg laying on oiled pear trees at
Storrs in 1978. We did not note a delay or reduction in egg lay-
ing in 1979 but we suspect that our oil treatments were applied too
late to have gained that benefit.
Hoyt , Westigard, and Burts (1978) have reported fenvalerate
(Pydrin) to be highly toxic to predators of spider mites in pear
orchards in the Pacific Northwest. In view of the current lack of
effective insecticides for pear psylla control, fenvalerate (Pydrin)
appears to be of considerable value, especially when used as pre-
bloom treatments. Early season treatments might allow predators
to recover in time to help manage summer spider mite populations.
Connecticut is now in the process of applying for a special
state registration to allow the use of fenvalerate (Pydrin) in 1981
for the control of pear psylla on pears.
A summer treatment of amitraz (BAAM) applied to all plots was
not highly effective in controlling pear psylla in our tests, and
was associated with considerable leaf scorch. It could not be
determined whether BAAM was directly responsible for this injury.
A period of several days of high temperatures and humidity following
the treatment may have contributed to the appearance of damage.
Further tests are needed to evaluate more fully the role of BAAM
for pear psylla control on pears in Connecticut.
References
Hoyt, S.C, P.H. Westigard, and E.C. Burts. 1978. Effects of two syn-
thetic pyrethroids on the codling moth, pear psylla, and various
mite species in northwest apple and pear orchards. J. Econ .
Entomol . 71: 431-434.
Zwick, R.W. and P.H. Westigard. 1978. Pre-bloom petroleum oil
applications for delaying pear psylla (Homoptera: Psyllidae)
oviDOsition. Can. Entomol. 110: 225-336.
ORCHARD PRACTICES NECHSSARY FOR GOOD PEACH PRODUCTION
lest G.
Rutgeri
Ernest G. Christ, Extension Poiiiologist
"s University, New Jersey
The peach industry is now and has been a stable segment of
the agriculture in New Jersey. The industry dates back to the
early 1600 's. Extensive orchards were planted by 1650 and the
industry grew until 1890 when there were over 4 million trees in
the state. Production per tree was low since there were only
775,000 bushels produced in 1890. Production improved as pest
control became a more standard practice and in 1920 from about
million trees the production was 2.1 million bushels.
o
The 1977 tree survey shows a total of all trees to be slightly
over 1 million with about 200,000 in the 1-3 year age. Today the
tree numbers are probably a bit above the 1977 survey figures based
on observations of tree planting in 1979 and 1980.
Production for the state in 1980 is estimated at about 2-1/2
million bushels. Production usually varies from 2 to 2-1/2 million
bushels annually. The most recent above-average crop was in 1971
when it exceeded 3 million bushels on the trees, and the poorest
crop in more than 40 years was in 1972 when only 500,000 bushels
were recorded.
Geographical location of New Jersey is especially suited to
peach growing as evidenced by the fact that the most recent freeze-
out of tlie entire crop and severe tree killing occurred in the 1934-
35 winter. Few if any other peach producing areas in the country
have been as fortunate.
Serious Problems and Solutions
There are serious growing and production problems and there is
constant change in growing, harvesting, handling and packing.
Tlie short life of peach trees is being discussed in grower meet-
ings and this is a problem in New Jersey as well as Georgia, South
Carolina, Michigan and several other areas of peach growing. V/e
have recommended and growers are following procedures for increasing
the vigor, health and life of the tree.
1
Talk presented at the Annual Summer Meeting of the Massachusetts
Fruit Growers' Association, Inc., July 10, 1980.
Much research has been conducted in an effort to increase the
life of a peach tree and Dr. E.F. Savage of Georgia devoted many-
years to this problem. As a result of his work and that of others,
including those in New Jersey, our cultural recommendations have
been updated and are as follows:
1. Soil fumigation is being practiced; both pre-plant and post-
plant treatments are made to reduce nematode populations. This
is an established practice in all peach growing areas since
soil fumigation has improved tree vigor and extended tree life.
Trees are less subject to cold damage and the virus disease
"Stem Pitting" is reduced through fumigation. Fumigant type
nematicides recommended for pre-plant treatment include DD* ,
Telone II*, EDB W-85*, Vorlex* and Telone 17*. Post-plant soil
fumigants recommended are Nemagon 12.1* and Fumazone 12.1*.
Non-fumigant nematicides include Furidan lOG* and 4F*, Nema-
cur 15c;* and 3SC*, and Vydate L* as a foliage spray.
2. Calcium nutrition is important. Keep the soil pH between 6 and
6.5 using calcium lime. Apply 1/2 to 1 pound calcitic limestone
mixed vvfith the soil around the roots at planting. Tiie late
Professor M.A. Blake stressed the need for N-P-K fertilizer
and liming to maintain a soil pil of 5.5 - 6.5 in the 1920's.
3. Painttree trunks with interior white latex (water base) paint
in the fall to reduce cold damage. This is most essential on
trees from 2 through 5 years of age. This reflects the sun's
rays and the temperature of the trunk of the tree is more nearly
the air temperature rather than 80 to 85 F as it can be on the
south side of the tree in January and February. Research in
this field was done in 1943-1944 by Dr. R. Eggert in New Hamp-
shire.
4. Prune peach trees in late winter, after the coldest weather is
past. March is a good time to start pruning if possible. If
pruning must begin before March, prune the oldest trees first
and the young last. It is better to prune young trees in bloom
than to prune in January or February.
5. Cytospora (Valsa) canker can be a tree killer if ignored. On
1- and 2-year-old trees, prune off infected portions if possible.
Cankers on the trunk that cannot be pruned out should be cut
out, removing all diseased tissue until healthy, green bark
shows. Paint the area with tree paint containing 2 tablespoons
of Benlate per pound of tree wound paint or white latex paint or
spray the trees with 1/2 pound Benlate 50WP* in 100 gallons
within a day or two after pruning and cutting out cankers.
A
Trade name
6. Stem Pitting virus is less a problem today than it was 10 or
15 years ago but it is present in some orchards every year.
It was a very serious problem in the late 1950's and was identi-
fied as a virus in the early 1960 's through the efforts of
Drs. J.C. Barrat, W. Virginia; S.H. Miretich and H.W. Fogel of
the USDA and Drs. F.H. Lewis, R.F. Stouffer and F.N. Hewetson
in PA. Nursery trees purchased today are far superior to those
of 15 years ago from the standpoint of being free of the Stem
Pitting virus. Nematodes transmit the disease and this is a
major reason for fumigating the soil. Bud wood selection by the
nursery is equally or more important.
Other Practices
Variety Selection . In New Jersey the two major requirements in
the selection of peach varieties for planting are cold hardiness of
buds and bacterial spot disease resistance. Observations during the
last 10 years make it possible to recommend a scries of varieties
that are superior in these two characteristics. Other desirable
qualities include fruit firmness, color, flavor, and size, and tree
vigor and growth characteristics. It isn't possible to find all of
the best in any one variety, perhaps, but a few varieties have the
2 major requirements plus several other desirable qualities. A
few of the best that we recommend in order of ripening include:
Candor, Garnet Beauty, Harbelle, Redhaven, Harken, Harbrite, Summer-
glo (NJ233) , Norman, Biscoe, Cresthaven, Jerseyglo (NJ244) and Emery.
A few nectarines that show promise include: Harko and Sunglo (Red-
haven season) , RedGold (Cresthaven season) and LateGold (Rio) .
Loring, Blake, Jerseyqueen and Rio-Oso-Gem are major varieties in
New Jersey and yet Loring, Jerseyqueen and Blake are not bud hardy;
Blake, Jerseyqueen and Rio-Oso-Gem frequently have serious infections
of bacterial spot and Rio is a poor tree. Blake is probably phasing
out and Jerseyqueen also, but wholesale market demand is a factor in
variety selection. Retail or pick-your-own selling can include some
varieties not the best for shipping.
Bulk Hauling . Bulk handling from the orchard to the packing house,
into the storage and on to trucks is common practice in practically
all orchards. Bulk hydrocooling has replaced packed box hydrocooling
in many operations for more rapid cooling and efficiency, especially
during heavy harvest.
Fruit Thinning . Growers have tried and used all chemical thinners
available as they appeared, and watched them disappear sometimes
with regret. Dinitro first appeared in the 1940's, and then through
the years NPA and CPA appeared, stayed for a while and then were
removed. There is no chemical for use on peaches today but Ethephon
will thin. Considerable research has been done regarding Ethephon
as a peach thinner beginning in 1968. One of the problems has been
leaf damage and heavy leaf drop but Dr. L. Edgerton in New York
has included ProGibb* in the spray with ethephon and eliminated
most of this damage.
In the absence of a chemical thinner, some limb shakers, a
few full tree shakers, clubs and whiffle bats are used to thin
the fruit, plus much hand removal. Thinning is a most important
cultural practice. Size is so very important in the wholesale
market and frequently, 1/8" increase in peach size will return an
additional $1.00 per 38 lb. box. Twice as many 2" peaches are
required to equal weight of 2-1/2" peaches. Peaches gain 41 a day
in volume as they approach harvest.
Pruning for Low Profile Trees . flost trees in New Jersey orchards
are being pruned to maintain a height of 7 to 8 feet. This makes
possible the pruning, thinning and harvesting without ladders.
Machine topping is extensive mainly with sickle bar mowers. Mowing
is done in the dormant season on most acreage but more and more
summer mowing is being done in orchards where tree and row spacing
permits. Summer mowing is usually done between July 15 and August 1.
There are several good reasons for summer mowing in addition to
accomplishing some pruning: more sunlight enters the tree, fruit
ripens more evenly and with less pickings, fruit color is improved
and better fruiting wood develops in the center of the tree.
Hand pruning is essential to complete any machine pruning to
maintain good tree vigor and the best fruiting shoots throughout.
Pneumatic pruners are used to some extent and custom pruning is
done on a sizeable acreage. There is room for improvement in the
pruning of much of the acreage but it's a time consuming, costly
job and too few people are willing or able to do the job properly,
so less than satisfactory pruning must be accepted.
Irrigat ion . Most peach orchards are equipped with some kind of
irrigation and during some time each year in late spring and summer
the irrigation is usually needed.
Tricke irrigation is established on perhaps 10 farms with capa-
cities ranging from 50 to 100 acres per farm. There is no strong
movement into trickle because of other equipment still in use and
the cost of establishing trickle. Irrigation is a very necessary
cultural requirement in peach growing.
Chemical Weed Control . Some orchards are grown in an established
sod, usually fescue, with chemical weed control in the tree row.
More of the orchards, especially in southern New Jersey, are culti-
vated with chemical weed control in the tree rows. Herbicides used
for annual weeds include simazine, terbacil, diuron and a combination
of diuron + terbacil. For established weeds, paraquat and dichlo-
benil are recommended.
"35
Trade name
10.
In one and 2-year-old orchards some growers combine 1-1/2 gal.
per acre of Furidan 4F* with the herbicide for nematode control
plus weed control.
Recent Innovations . Machine planting of peach trees is being done
on substantial acreage in the southern area of the state and pro-
bably will increase. There are only a few planters as of this date
but they are shared since a grower needs the machine for only a
a day or 2 to plant considerable acreage. The tree planter can not
be used in all soils but in New Jersey it can be used in the areas
where 901 of the peach trees are grown. Observations to date in-
dicate no serious problems. Some orchards have completed 4 years
and trees are growing well. Usually the trees are lined up in one
direction only so cross cultivation or spraying is not easily done.
Trees could be set on the square but this requires more time and
effort and many growers feel this is not necessary. Subsoiling be-
fore planting is recommended where old trees have been removed and
limestone placement in the subsoil is also recommended.
Hedgerow planting is being tried in one orchard rather extensively
and a few other plantings have been made on a limited acreage. Trees
are planted 10 feet in the row and the rows are 15 feet apart. Trees
are summer mowed vertically and across the top at about 10 feet.
The width of the trees is held about 5-4 feet. Some hand pruning is
done in the dormant season to remove diseased and broken limbs and
any strong growth growing into the row middle. As with trellised
trees, there should be an open space for cross traffic at about 50
foot intervals.
******
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, Nev/ Hampshire. The meet-
ings are scheduled for January 7 and 8, 1981.
The hotel is accessible from all major highways. Routes 3 and
93, which lead to Concord, are accessible from anywhere in Massa-
chusetts. 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.
a
Trade name
11.
INTEGRATED MANAGEMENT OF APPLE PESTS IN MASSACHUSETTS
1980 RESULTS: INSECTS^
W.M. Coli , G.E. Morin , N.D. Goodliue , M. Kuzontkoski , T. Green ,
4 5 6
M.R. Paul , S. Marafino , and R.J. Prokopy
Summary of Res ul ts .
Intensive weekly scouting and grower advisement
in 18 good-cooperator IPM blocks, resulted in a
savings in insecticide, aphicide, and miticide
spray use (dosage equivalents) of 40%, 97% and
56% respectively. Permanent type fruit injury
was 8% lower in IPM than Check blocks. Cost
benefit analysis indicated an average net savings
from IPM of $93.37 per acre.
Compared with previous years, 1980, the third year of
operation for the Massachusetts apple IPM program, was char-
acterized by significant changes in number o£ orchards scouted,
grower financial support, grower participation in orchard
scouting and sampling methodology ^.
Program objectives continue to be: 1) to aid in the pro-
duction of high yields of high quality fruit while reducing the
amount of pesticide usage; and 2) to encourage the use of spray
materials which allow for survival of beneficial predators and
parasites .
1
Special thanks to Mr. David Chandler, Meadowbrook Orchards, Inc.,
Sterling Jet. for allowing us to room 2 scouts at his housing for
harvest labor throughout the summer which allovved significant
savings in travel time and gasoline.
2
Pest Management Specialist
3
Senior Field Scouts
4
Field Scouts
5
Lab Technician, Entomology Department
6
Extension Entomologist
7
Reduced spray programs on apples have been discussed in previous
issues of Fruit Notes [41(1), 41(2), 41(3) and 43(3)1], and our
1978 and 1979 results were summarized in Fruit Notes 44(1) and
44(6).]
12.
Number of orchard blocks scouted
iiach week, field staff visited 25 IPM blocks in 16 commercial
orchards throughout the major fruit growing regions in Massa-
chusetts. IPM growers received a weekly written scouting report
and were contacted either in person or via telephone by the IPM
Specialist and advised as to the need for spraying, materials to
use. and timing .
In addition, we monitored Check blocks in 6 commerical orchards
on a weekly basis when possible. Insect monitoring was identical
to that in IPM blocks, although growers followed their own pesti-
cide application program with no advice from us.
Also, 4 orchards were Alternate Middle vs. Every Middle spray
blocks. We will discuss the results of this aspect of the program
in the next issue of Fruit Notes .
Grow e r financial support
The majority of funding for the IPM program continues to be
the original 5 year USDA Grant which began in 1978. However, in-
asmuch as USDA funds for scouts are scheduled to decrease each
year and grower support for scouts is meant to increase, partici-
pating IPM orchards were charged $300 for combined insect and dis-
ease scouting and advice or $200 for insect scouting and advice
alone. Growers paid a total of $4,500 into a special Extension
Activity Fund, which was used exclusively for paying scout salaries.
No fee was assessed Check or Alternate-Every Middle orchards.
Grower participation in orchard scouting
In response to substantial grower interest we offered a series
of training sessions to acquaint growers or designated orchard
personnel with insect identification and life histories, IPM
monitoring techniques, and recommended control measures. These
"grower scouts" were encouraged to participate in weekly scouting
and data collection in their IPM blocks, and to scout additional
blocks of their orchard on their own. Of the 16 IPM orchards, 11
utilized "grower scouts" on a weekly basis, 4 used them sporadically,
and 1 not at all. Interest in the "grower scout" concept appears
to be high, and may offer a means for growers to continue to im-
plement IPM programs after September, 1982 when Federal funding is
scheduled to end.
Sampling methods
Weekly, intensive orchard monitoring continues to provide
the soundest basis for accurate pest management decision making
and grower advisement. However, if IPM techniques are to be applied
to large orchard acreages, more rapid methods of accurately esti-
mating insect densities are desirable. For this reason in 1980
we utilized fewer trapping stations per block (1 per 2-3 acres)
than in 1978 or 1979 (1 per 1-2 acres), although time spent at
each station was similar to previous years.
13.
Sampling stations were usually near the block periphery,
2 or 3 rows in from the border while one station for pheromone
(sex odor) traps was positioned in the block center. Visual
traps were used to monitor tarnished plant bug (TPB) , European
apple saAvfly (EAS) , and apple maggot fly (AMF) adults. Pheromone
traps were used to monitor Codling moth (CM), Oblique banded
leafroller (OBLR) , redbanded leafroller (RBLR), San Jose' scale
(SJS) , tufted apple budmoth (TARM) , and spotted tentiform leaf-
miner (STLM) males. Mites and mite predators were monitored using
leaf brushing techniques ( Fruit Notes 43(4)) from mid June to
harvest. Plum curculio (PC), green fruitworm (CFW), green apple
aphids (GAA) , and their predators, woolly apple aphids (WAA) and
STLM were monitored by examining ID fruiting spurs or foliar ter-
minals in each of 3 tree areas (top, low inside and low outside)
at each trapping station.
Immediately prior to appropriate harvest dates for early, mid,
and late season apple cultivars, insect injury levels were deter-
mined in each IPM and Check block using on-tree surveys of 400-
1600 fruit per block (100 fruit per tree from each of 2 trees
adjacent to trapping stations). In addition, we sampled at har-
vest fruit injury from anotlier block in each IPM orchard of
similar tree size and varietal composition. Injury in tliese
blocks was determined by on-tree surveys of 1000 fruit per block
(100 fruit per tree from trees randomly located within the block).
Results
Fruit injury
At harvest, fruit injury was divided into categories: 1) in-
jury to the skin or flesh (= permanent injury); and 2) injury
confined to the skin surface (= temporary injury usually removable
by washing, i.e., WAA in the stem cavity, sooty mold (SM) on aphid
honeydew, or white apple leafroller (WAL) excrement).
Drawing on the experience of IPM researchers in other states,
we analyzed harvest injury levels (Table 1) and spray application
totals (Table 2) taking into account the degree of adoption of
IPM recommendations by participating growers. Specifically those
growers who followed more than 60"o of spray recommendations were
considered "good" cooperators , while those following less than 60-6
of these recommendations were considered "partial" cooperators.
Overall, permanent fruit injury was only 2S% as great in good
cooperator IPM blocks as in partial cooperator blocks, 501 as great
as in same orchard non IPM blocks and 92% as great as Check blocks.
These data indicate that partial cooperation with IPM recommendations
can result in poorer quality fruit than if growers follow their own
spray approach without IPM advisement.
14
Table 1. Average percent insect injury on fruit at harvest in
good or partial cooperator IPM and in Check commercial orchards
in Massachusetts, 1980.
1980 in;
jury (%)^
Insects Good
Partiaiy
Same orchard^
CO
operators
cooperators
non IPM
Check
(18 blocks)
(5 blocks)
(13 blocks)
(9 blocks)
Permanent
injury
SJS
0.72
11.8
4.26
1.43
TPB
1.44
2.0
2.09
1 .44
PC
1.19
1.28
1.00
0.87
EAS
0.24
0.46
0.22
0.11
AMF
0.10
0.04
0.09
0.14
CM
0.04
0.0
0.0
0.0
LR
0.02
0.04
0.05
0.03
GFW
0.01
0.02
0.0
0.07
Total per-
3.76
15.64
7.71
4.09
manent in-
jury ("o)
Temporary
injury
WAA
0.05
0.0
0.15
0.0
WAL
0.64
0.0
1.49
0.11
SM
0.03
0.0
0.33
0.08
Total tem-
0.72
0.0
1.97
0.19
porary in-
jury i°i)
Total Per-
cent insect
injury (per-
manent and
temporary)
4.48
15.64
9.68
4.28
z
Based on on-tree survey of 600-1600 fruit per block at harvest
(100 fruit per tree from each of 2 trees adjacent to trapping
stations) .
y
Partial cooperators were those who followed less than 60% of
advised spray recommendations.
X
Does not include "partial cooperator" blocks.
Removable fruit injury was only 37% as great in IPM as in
same orchard non-IPM blocks, but 74% more than in Check blocks,
while no superficial type injury was found in partial cooperator
blocks .
15.
Specifically, TPB remained a highly damaging fruit pest in
Massacliusetts commercial orchards (Table 1) , as was the case
in 1978 and 1979. Tarnished plant bug injury in IPM and Check
blocks was identical inspite of higher pest pressure in IPM blocks
(7.4 TPB adults per trap in IPM vs. 6.0 adults per trap in Checks),
Continuing our attempts to develop a TPB grading index, we found
that bl% of TPB injured fruit would grade through as US Fancy,
while 351 would grade US No. 1 and 6% would be culled. This high
percentage of very minor TPB injury may relate to the rapid, early
buildup in TPB populations before pink, when feeding results pri-
marily in bud abscission rather than serious scars resulting in
downgrading of fruit value.
San Jose scale continues to be a serious pest of apples in
Massachusetts, although injury in IPM blocks was only SC^ as
great as in the Checks. The high average injury due to scale in
partial cooperator blocks resulted from one grower's failure to
treat for scale with prebloom oil, despite advice to do so. The
result was scale injury on 55% of fruit sampled.
Plum curculio injury was substantially higher in all blocks
in 1980 than in 1979 even though some growers applied as many
as 4 insecticide sprays to control this pest. Injury in IPM
blocks was 271 greater than in Checks, due primarily to 9.4%
PC injury in one block (the grower was unable to apply a recom-
mended spray over the May 24-26 weekend, when PC activity was
high, because beehives were still in the orchard).
Trap captures of AMF adults were higher than in 1979, as was
the injury from this pest in both IPM and Check blocks. In
one IPM block, no AMF adults were captured until August 15, and
CM captures were also low. As a result no insecticide sprays
were applied between June 9 and August 15, and no AMF sprays
were needed thereafter. Our harvest injury survey found no injury
from either of these pests in this block, pointing out the poten-
tial savings to growers that may result from use of sticky sphere
and pheromone traps for AMF and CM, respectively.
No spray applications were required in any IPM blocks for
CM, LR, or GFW, and combined injury from these pests was slightly
lower in IPM than Check blocks. Injury from WAA, WAL and SM was
substantially higher in IPM than Check blocks, due principally
to high (6.91) WAL injury in one IPM block. Inasmuch as speckling
from WAL excrement is superficial and would probably be removed
by normal post harvest handling, it is doubtful that this "injury"
is of economic importance.
Mite populations
Populations of harmful plant feeding mites were virtually id-
entical in IPM and Check blocks in 1980. European red mite and
two spotted mite numbers generally peaked in late July and early
August, in response to hot dry weather, and may have caused some
fruit drop at populations lower than would normally be expected
to cause drop. Perhaps mite feeding combined with the stress of
16
below average rainfall contributed to tliis phenomenon. Apple
rust mites, which cause little damage except at very high popu-
lation (about 300/leaf) but may serve as an alternate food source
for Amblyseius fallacis , were found in substantially higher numbers
in IPM than Check blocks.
Table 2. Mean abundance at peak sampled population of pest and
predaceous spider mites in relation to acaricide sprays, 1980.
Acaracide
dosage
Number of mites per leaf
Two- Apple
equivalents European spotted rust Amblyseius
Orchard type Oil Other red mite mite mite fallacis
IPM 1.0 0.8
IPM partial
cooperator? 0.7 1.4
Check 1.1 1.8
8.1
6.2
8.4
2.0
3.2
1.9
66. 5
50.4
22.4
0.07
0.02
0.03
„ . T ^ Actual pesticide rate/100 gal
Dosage equivalent = -t — r '- 1 — r~- o^ — . . ^ — -
^ ^ Amt . recommended m Southern
New England Apple Pest Control
Guide
Predator mite numbers were insufficient to achieve biological
mite control because they never exceeded 0.5 per leaf in any block.
We believe that the lack of snow cover during the 1979-80 winter
may have resulted in substantial overwintering mortality to A.
fallacis , as was the case in Michigan after a recent winter with
similar conditions.
Insecticide, aphicide and miticide use .
IPM blocks received 26% fewer insecticide sprays (average 6.5,
range 5-9) than the Checks (average 8.8, range 5-12} or same orchard
non-IPM (average 8.8, range 5-10]°. These results appear to indicate
that growers (same-orchard non-IPM and Check) are implementing some
aspects of IPM on their own. Partially cooperating IPM growers
applied 11°6 fewer sprays than good cooperators. However, any sav-
ings in spray material and application costs were negated by sub-
stantially higher fruit injury levels in these blocks.
IPM growers applied 26% and 531 fewer miticide sprays compared
to Check and partially cooperating 1PM growers, respectively (Table
3). Use of oil as an ovicide was nearly identical in IPM and
Check blocks, but 36% lower in partial cooperator blocks.
8
Data incomplete
17.
Table 3. Number of pesticide treatments and dosage equivalents
of pesticide applied for insect and mite pest control in IPM
and Check blocks, 1980.
IPM as
IPM partial % of
Number of treatments IPM cooperators Check Check
1.0 110
8.8 74
2.0 70
0.5 20
Oil
1.1
0.7
Insecticide
6.5
5.8
Mit i cide
1.4
3.0
Aph icide
0.1
0.3
Number of dosage
equivalents
Oil
1.0
0.7
Insecticide
4.8
5.5
Mit icide
0.8
1.8
1.1 90
8.0 60
1.8 44
Aphicide 0.01 0.3 0.4 3
•7
. , ^ Actual rate/100 gal water
Dosage equivalent = -^ 1 — -^ r — ^ ? tl — „
^ ' Recommended rate m Southern
New England Apple Pest Control
Guide
While there was a substantial reduction in spray application
trips, there was an even greater reduction in number of dosage
equivalents of insecticides, aphicides and miticides in IPM com-
pared with Check blocks (60, 3 and 44^o as much used, respectively).
(Table 3.) .
Pesticide use 1977-80
Figure 1 shows t7ends of pesticide use in IPM and Check blocks
in recent years. It is interesting to note in (Figure la and Figure
Ic) that a general reduction in pesticide dosage equivalents has
occurred. Although IPM orchards use substantially less pesticides.
Check orcliards also appear to be utilizing some IPM information as
well. In addition, the rapidly rising costs of pesticides (petro-
chemical derivatives) probably accounts for some portion of this
overall downward trend in spray material usage. As more sprays are
IS
c
O
>
O
</)
O
Q
(/)
•*—
c
O
>
"5
cr
UJ
a>
o
(n
o
Q
5,
2
a. Insecticide Usage
IPM ■ — ■
CHECKd-
-D
-- ^ of Blocks ( )
84-
/9)S 4
b. Insect Injury to
Fruit at Harvest
2..
d. Mean Abundance
of Spider Mites
at Peak Populatio
Trends in pesticide use, injury to fruit, and spider mite
populations. 1977-1979.
required for STLM and SJS control, however, it is possible that
this trend may be reserved in the future years.
19
Cost and benefit comparisons
Table 4 summarizes our cost benefit analysis of IPM vs. Check
blocks. IPM orchards realized substantial savings in spray mat-
erials and application costs per acre compared to Checks. (Table
4). (All calculations were done using suggested retail prices,
with no attempt made to account for grower liulk rate discounts,
which vary considerably).
Table 4. Cost benefit analysis of insect and mite results in 18
IPM and 9 Check commercial apple blocks in Massacliusetts , 1980
Parameter
Orchard
IPM
Check
(Avg. no. sprays/A )
Oil
Insecticides
Aphicides
Mit icides
( Avg. no. of dosage
equivalents for)^
Difference IPM
vs . Check
1
6
1
(Avg.
insect injur
T
("OJ
y
(Avg.
application
cost
/ A)^
(Avg.
cost/A
spray
materials)
Oil
Insecticides
Aphicides
Miticides
3. 7 7
$26.45
$18. 53
55.54
1.50
20.30
1.0
8.8
0.5
2.0
Oil
1.0
1.1
Insecticides
4.8
8.0
Aphicides
0.01
0.36
Miticides
0.8
1.8
4.09
$34. 27
$21
98
5
39
37
04
89
79
(Numerical)
0.32
$ -7.82
$
-2.84
-42.50
-4.30
-19.49
(%)
+ 0.1
+ 10
-2.3
-27
-0.4
-80
-0.6
-30
0.1
-10
3.2
-40
0.35
-97
1.0
-56
( Avg. value/A of
fruit loss due
to insect injury )w $200.96 $217.38
( Avg. net benefit/A from IPM
$-16.42
$+93.37
' - , ^ Actual pesticide rate/100 gal
Dosage equivalent = Recommended rate in Southern
New England Apple Spray Cuide
r
Does not include injury from sooty mold, white apple leafhopper
and woolly apple aphids which could be removed by washing fruit.
Based on 15 min. time to spray 1 acre, $5.50/hr. labor cost and
$2 . 20/acre/application for fuel and oil.
Based on average values as of October 10: US Fancy Fruit $11.33/bu,
US n fruit $7.00/bu., cull fruit $1.60/bu. and average yields
of 550 bu./acre.
w
20.
Average value of fruit loss per acre was $16.42 lower in IPM
blocks as well, resulting in an average net benefit per acre of
$93.37 from IPM scouting and grower advisement.
It should be noted that savings in spray materials and appli-
cation costs seen in 1978, 1979 and 1980, are only the most immed-
iate benefits of IPM. IPM has essential long-term benefits as
well in reducing selection pressure for pesticide resistance and
thus greatly delaying development of resistance, and prolonging
tlie period of usefullness of currently available spray materials.
FRUIT NOTES INDEX FOR 1980
(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/ Feb urary
Further Trials with Naphthalene Acetic Acid (NAAJ for Tree
Training. (1-2)
Winter Injury to Fruit Trees in 1978-79.(2-6)
Winter Injury in New Hampshire - A Grower Survey (7-8)
Progress Report: Height Containment on Spartan and Idared Trees (8-14)
Alternate vs. Every Middle Spraying for Apple Pests in 1979(15-18)
March/April
Airblast Sprayers for Orchard Spraying (1- 6)
Spotted Tentiform Leafminers : Biology, Monitoring, and Control (7 - 12)
More About Nematodes and Fruit Trees (13-14)
May/June
The Way You Fertilize Your Fruit Trees Can Affect the Quality of
the Fruit You Harvest (1-4)
Suggestions for Use of Calcium Sprays in 1980(4-5)
Suppressing Weed Growth Under Fruit Trees (5-6)
Pomological Paragraph- Pruning at Planting (6-7)
Influence of Pruning Peach Trees Late in the Spring(7-8)
The Use of Promalin to Elongate Delicious Apples: Research Obser-
vations and Suggestions for Use in 1980 (8-12)
Soil Management of Peach Trees (12-15)
Sampling Methods and Provisional Economic Threshold Levels for
Major Apple Insect and Mite Pests in Massachusetts (15-18)
Managing Mummy-Berry Disease of Blueberries in Massachusetts (19- 21)
July/August
Progress Report: Scion/Rootstock and Interstem Effects on Apple
Tree Growth and Fruiting (1-2)
Soil, Tree, and Fruit Response to Lime and Type of Nitrogenous
Fertilizer Applied at Two Timings Under Sturdeepsur Delicious
Trees (3-7)
How Ethephon is Being Used to Advance the Maturity of Apples in
Massachusetts (7-12)
Excessive Apple Bud Abscission in 1980: Was It Caused by Tarnished
Plant Bug Feeding or Cold Temperatures? (13-14)
21.
TRUIT NOTIiS INDEX fcontinued)
Sept ember /October
Progress Report: Pruning Effects on Tree Growtli and Fruiting
of Spartan Apple (1-8)
Do Calcium Chloride Sprays Affect Apple Maggot Fly Egglaying? (9- 10)
Causes of Defects on Mcintosh Apples at Packing Sheds and
Their Effects on Returns. (10-14)
Controlling Orchard Mice. (15-16)
November /Dec ember
Evaluation of Several Pear Psylla Control Programs in Connecti-
cut (1-5)
Orchard Practices Necessary For Good Peach Production (6-10)
New England Fruit Meetings and Trade Show (10)
Integrated Management of Apple Pests in Massachusetts 1980
Results: Insects (11-20)
COOPERATIVE EXTENSION SERVICE
U.S. DEPARTMENT OF AGRICULTURE
UNIVERSITY OF MASSACHUSETTS
AMHERST, MA 01003
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. 46 No. 1
JANUARY/FEBRUARY 1981
TABLE OF CONTENTS
Calyx-End Rot of Apples in Massachusetts
Disease Results for the 1980 Integrated Pest
Management Program for Apples in Massachusetts
Research in Progress
I. Scion/rootstock and interstem effects on
growth and fruiting of apple trees.
II. Effect of rootstocks and stempiece/
rootstock combinations on the tree
performance and fruit quality of Mcintosh
and Delicious strains
III. Fruit variety evaluation at the Horticultural
Research Center
IV. Adaptability of apple tree rootstocks to
representative orchard soils in Massachusetts
V. Effect of soil water and depth to hardpan
on rootstocks
An Update on Fruit Trees Injured in 1978-79
Alternate vs. Every Middle Spraying for Apple Pests:
1980 Results for Arthropod Pests and 5-year Trends
NOTICE
The Massachusetts Cooperative Extension Service is
faced with a crisis situation relative to funds. There-
fore, in 1981 there will be only 4 issues of FRUIT NOTES
a winter, spring, summer and fall issue.
CALYX-END
ROT
1
OF APPLES IN MASSACHUSETTS
T.R. Bardinelli , C.W,
Department of
McCarthy , and W.J. Manning"
Plant Pathology
During the 1980 apple growing season, calyx-end rot disease
caused greater than usual losses. Calyx-end rot is caused by
the fungus Sclerotinia sclerotiorum . This organism has a wide
host range, including many vegetable and ornamental plants.
The first symptoms were observed as a dry tan-colored rot
on the calyx end of young fruits during mid- July. Often the
surrounding tissue ripened prematurely causing the epidermis
in this area to turn red. The red areas make the diseased fruits
highly visible. Severely affected fruits may drop prematurely.
Other fungi can quickly invade the weakened fruit and furth(
decay results if adequate moisture is available.
ler
The
is not w
and may
periods
fected f
(1/4 - 1
the rest
can rema
small br
proper e
structur
again oc
life cycle
ell unders
extend int
are probab
ruits drop
/2" diamet
ing or ove
in dormant
own apothe
nvironment
es are pro
cur.
of S. sclerotiorum on app
tood. Infections probably
o June from windblown asco
ly necessary for infection
and decompose, small hard
er) called sclerotia are p
rwintering stage. On othe
for up to 3 years, Scle
cia during late spring or
al conditions occur. Asco
duced and windblown to the
les in Massachusetts
begin during bloom
spores. Wetting
After the in-
black structures
reduced. This is
r crops , sclerotia
rotia give rise to
early summer if
spores from these
host where infections
The average incidence of calyx-end rot in Massachusetts
during 1980 was 2%. Severely affected orchards had losses of
4-8% in Red Delicious and Mcintosh blocks. The most susceptible
varieties appeared to be Milton, Macoun, and Mcintosh. Red
Delicious and Cortland fruit were also susceptible to calyx-end
rot but to a lesser extent and Golden Delicious appeared to be
the least susceptible.
Extension Technician
Extension Aide
Associate Professor
Two severely affected orchards were routinely surveyed for
this disease in 1980 and the data in Table 1 show the percent
of infected fruits for the period between mid-July and mid-
September .
Table 1. Percent calyx-end rot fruit infection in two severely
affected orchards in Massachusetts, 1980.
Orchard
July
Au
gusi
S(
3ptember
10
16
30
13
27
17
1
2
4.0
3.9
6.0
8.9
1.6
4.9
1.2
5.2
1.6
4.7
1.2
2.6
Average 3.95 7.45 3.25 3.20 3.15 1.90
The highest incidence of calyx-end rot was observed on July
16 with an average of 7.451. Many of the diseased fruit dropped
prematurely and only 1.9% of the fruits on the trees September 17
were infected. Visual examinations of infected fruits on the
trees at harvest showed a successful walling-off and healing of
the previously rotted calyx-end.
Calyx-end rot and other blossom end rots of apple fruits can
easily be confused. The only reliable way to determine the cause
of calyx-end rots is to culture tissues on media in the laboratory
and identify the fungi that grow out. Many different fungi have
been associated with calyx-end rots of apple, including Botrytis
cinerea , Alternaria spp . , Physalospora obtusa , and Sclerotinia
sclerotiorum .
Isolations were made in mid-July from 200 fruit with early
symptom expression and in early August from the same number of
fruit with late symptom expression (Table 2) .
Table 2. Occurrence of various fungi from calyx-end rot isolations ,
Early symptom isolations Late symptom isolations
I Incidence % Pure culture 1 incidence % Pure culture
Sclerotinia
60 36 18
57 21
20 1
13 6
sclerotiorum
98
Alternaria
spp.
34
Botrytis
cinerea
14
Other
Ninety-eight percent of the isolations from apples with early
symptoms yielded S. sclerotiorum and 601 were pure culture. This,
plus pathogenicity test results, indicated that S. sclerotiorum
was the probable cause of calyx-end rot. Isolations from fruit
with advanced symptoms showed a marked decrease in S. scle r otiorum
and an increase in the isolation of other saprophytic and weakly
pathogenic fungi. This illustrates the importance of early dia-
gnosis in determining the cause of a calyx-end rot disease of
apple.
Our observations indicate that an adequate apple scab spray
program may not prevent an outbreak of calyx-end rot, as both of
the affected orchards surveyed had excellent management of all
other apple diseases.
**********
DISEASE RESULTS FOR THE 1980 INTEGRATED PEST MANAGEMENT
PROGRAM FOR APPLES IN MASSACHUSETTS
T.R. Bardinelli-^, C.W. McCarthy^, and W.J. Manning^
Department of Plant Pathology
During the 1980 growing season, 11 commercial apple orchards
cooperated in the disease management aspect of the Integrated
Pest Management (IPM) Program. IPM and Check blocks were located
in the same orchards.
The disease management strategy for the IPM program was based
on biological and environmental monitoring, such as apple scab asco-
spore release data, tree growth stage, length of leaf wetting per-
iods, and average temperature during these wetting periods. These
factors were most important during the primary apple scab season,
as determined by the period of ascospore release. Spray decisions
were based on the Mill's Table which gives the approximate number
of hours of leaf wetting required at various temperatures for the
occurrence of a light apple scab infection.
1
Extension Technician
2
Extension Aide
3
Associate Professor
Consideration was given to other diseases in addition to
apple scab when choosing fungicides. Most sprays were applied
after an apple scab infection had been determined. Intervals
between sprays were at least 7 days and fungicides were incorpor-
ated with insecticides whenever possible. Occasionally preventa-
tive sprays were applied on a management decision basis, rather
than a calendar basis. Only fungicides with an adequate kickback
action were recommended.
The end of the primary apple scab season was determined by
the end of apple scab ascospore release. Fungicide applications
recommended after this time was based on each orchards ' s specific
disease problems. In certain orchards, only 1 or 2 fungicide
applications, at approximately 1/4 to 1/2 dosage rate, were applied
after the primary scab season. Fungicides were no longer applied
after infection but rather incorporated with an insecticide or
other type sprays.
Results and Discussion
The results of 1979 and 1980 IPM programs are compared in
Table 1 to demonstrate trends associated with the program.
Table 1. Cost benefit analysis for fungicide usage and fruit quality
on IPM programs in 1979 and 1980.
1979 1980
IPM Check IPM Check
Number of fungicide sprays 10.64 13.00 9.45 10.36
Dosage equivalents 9.77 11.11 8.11 8.80
Fungicide cost per acre ($) 74.06 88.68 85.26 94.58
Percent diseased fruits at harvest 0.99 0.93 0.88 0.90
Loss to disease per acre ($) 46.28 43.48 50.31 56.30
IPM net benefit per acre ($) 11.82 15.31
The reduction in the number of fungicide sprays in the IPM
blocks in comparison to Check blocks was 18% and 9% in 1979 and
1980, respectively. The amount of fungicide used in the IPM blocks
also was reduced by 12% in 1979 and by 8% in 1980. Since the in-
cidences of diseased fruit in the IPM and Check blocks were very
similar both years, the savings of $11.82 and $15.31 per acre in
1979 and 1980, respectively were mainly the result of reduced fungi-
cide usage. Savings were greater in 1980 because of inflation even
though the reduction in fungicide usage was less than in 1979.
5.
We have noticed that growers tend to apply some information
from IPM blocks in the remainder of their orchards. A more dramatic
difference in fungicide usage can be noted in Table 2 where we also
included non-IPM commercial orchards in our comparisons.
Table 2. 1980 spray record comparisons in Massachusetts.
Types of orchards
IPM Check Commercial
Number of fungicide sprays 9.45 10.36 12.00
Dosage equivalents 8.11 8.80 10.55
Cost of fungicide per acre ($) 85.26 94.58 120.56
IPM orchards had 21% fewer fungicide spray applications and
used 23% less material than other commercial non-IPM orchards.
This amounts to a $35.30 per acre savings.
The results clearly show monetary savings for Integrated Pest
Management and the use of environmental and biological monitoring
for more efficient use of fungicides. It is realized, however,
that it is difficult to spray large acreages on an after- infection
or kickback program. New pesticides with extended kickback action
(up to 92 hours) are presently being used on an experimental basis
and might solve this problem in the future. We are also working on
a spray prediction program based on fungicide residue sampling on
apple foliage. This program may aid in the timing of fungicide
applications and help reduce fungicide applications.
**********
RESEARCH IN PROGRESS
In January, 1981 the personnel who conduct pomological research
at the University of Massachusetts reviewed their projects with
members of the Massachusetts Fruit Growers' Association-University
of Massachusetts Fruit Advisory Committee. Perhaps our readers also
would like to know how the University of Massachusetts is attempting
to serve the fruit industry in Massachusetts through research.
Therefore, during the next several issues of FRUIT NOTES, we plan to
have the leader of each project write a brief report that will state
why the project was initiated and the major findings to date. The
reports will appear under the heading of RESEARCH IN PROGRESS.
I . Scion/ r ootstock and interstem effects on growth and fruiting
of apple trees . William J. Lord
New rootstocks and also virus-free clones of both rootstocks
and varieties became available during the 1970's. A surge of
interest also developed in interstem trees due to the high cost
of providing support for trees on M9 , and an interest in high
density plantings. Thus, our basic objective in this project is
to evaluate tree size, yield, production efficiency and fruit
quality of several varieties on various rootstocks and interstem/
rootstock combinations.
Unfortunately, our oldest rootstock and interstem trials are
only 5 years old, which is short when one considers the long life-
span of apple trees. Nevertheless, our data and observations to
date show that interstem trees, particularly with Empire as the
variety, are more time consuming to train than are trees on more
vigorous rootstocks such as M7 , It has been necessary to stake
many interstem trees to support the leaders and to eliminate tree
leaning.
Suckering is profuse on interstem trees planted with the stem-
piece/rootstock union 2 inches above ground level, whereas it can
be minimized by deeper planting.
The presence of burrknots on the M9 stempiece is readily
apparent when the stempiece rootstock union of interstem trees is
above ground. On many trees the burrknots are large and numerous
and their presence has caused the stempiece to become twisted and
distorted .
In plantings established at the Horticultural Research Center
in 1976, Empire trees on M9/MM111, M9/0ttawa 11, and M9/Antonovka
are larger and have been more productive than Sturdeespur Delicious
on similar interstem/rootstock combinations. Trees on M26, which
in general are doing poorly in many commercial orchards, have per-
formed well to date, Rogers Mcintosh has had higher production
efficiency on M26 than on M7 or MM106. Rogers Mcintosh on M26,
M7 or MM106 began fruiting in 1978 (in the 3rd leaf) whereas the
first crop of Gardner Delicious on the same rootstocks was harvested
in 1980.
A planting of Empire on M26, M27, M9 , M9/MM106, M27/MM106,
M9/^0^111 or M27/MM111 was established at the Atkins Orchards,
Belchertown, MA in 1976. After 5 growing seasons differences in
tree spread are still small, although the spread of trees on M9
and M27 is less than that of trees on M9/MM106, M27/MM106 and M26.
7.
M27 is producing the smallest tree but has the highest produciton
efficiency of the various rootstock and interstem combinations.
A planting of Starkspur Supreme Delicious (Pagnelli strain)
on M9, EMLA-'-g, EMLA27, EMLA7 , EMLA26, MAC^9, MAC24 , OAR^I, and
Ottawa 3 was established in 1980 at the Horticultural Research
Station. In 1981, a planting of Starkrimson Delicious (Bisbee)
strain) on M27, C6/Antonovka , P2 Antonovka , and P22/Antonovka
will be established.
The effects of the rootstocks and interstem/rootstock com-
binations on fruit maturation and quality in our plantings will
be evaluated in the future.
*********************
II . Effect of rootstocks and stempiece/rootstock combinations
on the tree performance and fruit quality of Mcintosh and
Delicious strains . F.W. Southwick
In Spring, 1979, a randomized replicated Mcintosh rootstock
trial was planted at the Horticultural Research Center. Both
Rogers and Macspur strains are being tested on four rootstocks
planted in rows 20 feet apart: M7A, M26, M9 , and M9/MM111. On
M7A, Rogers and Macspur are planted 16 and 14 feet apart, respect-
ively, in the row. On M26 and M9/MM111 they are planted 14 and 12
feet apart, respectively and on M9 they are planted 10 and 8
feet apart, respectively. All combinations are being trained as
staked free-standing trees to a slender spindle system. In addi-
tion, both Rogers and Macspur on M9 are also being trained as
staked trees on a 4-wire trellis. Bisbee and Vance Delicious and
Cortland serve as pollenizers.
All blossoms were removed in 1979 and 1980. Training began
in 1980, and cross-sectional areas of all trees were taken. In
1981 training and measurements will continue and fruiting may be
allowed to begin.
1
EMLA(East-Malling and Long Ashton) : virus-free
2
Introduced by Michigan State University
3
Selected by Oregon Agricultural Experiment Station
8.
In Spring, 1981, a similar randomized replicated Delicious
rootstock trial will be planted. Both Gardner and Bisbee strains
will be planted on M7A, M26, MMlll, M9/MM111, and M9/MM106 root-
stocks. Gardner and Bisbee on M7A and MMlll will be planted 16
and 14 feet apart in the row, and they will be planted 14 and 12
feet apart, respectively, on M26, M9/MM111, and M9/MM106. All
trees will be trained as staked free-standing trees to a slender
spindle system. Rogers Mcintosh and Cortland will be the pollen-
izers. Training and cross-sectional measurements will begin in
1981.
As these plantings develop, it is intended that numerous eval
uations will be made, including the following:
a. annual yields per tree
b. each tree's production efficiency
c. tree survival
d. prevalence of rootstock suckering
e. nutritional status of each tree, and fruit
susceptibility to bitter pit
f. fruit maturation (firmness, red color develop-
ment, watercore, etc.)
g. postharvest storage life and susceptibility
to physiological disorders following Ca and
regular cold storage.
********************
III. Fruit variety evaluation at the Horticultural Research Center .
James F. Anderson
We are beginning a new phase in tree fruit evaluation at the
Horticultural Research Center. This has been made possible by the
removal of several of the original plantings made in 1964. Because
of space limitations very few new varieties or selections were
planted between 1965 and 1978.
Most of the varieties and selections under test in these orig-
inal plantings have been reported on at past meetings and in earlier
reports. Two varieties that have not been reported earlier are
Akana (TOHOKU #3) and Magnolia Gold. Akana looks promising for
early September apple market and Magnolia Gold is an attractive,
good quality Golden Delicious type apple, that has been completely
russet free in our trials.
Plantings of apple varieties in the past 2 years include a
number of strains of Red Delicious, Mcintosh and Cortland. Addi-
tional apple varieties will be set next spring.
9.
The peach orchard set in 1980 has 15 peach and 6 nectarine
varieties under evaluation. Five pear varieties have been added
for evaluation in the past 2 years. Additional pear varieties
will be set next spring.
Small fruit varieties and selections are also evaluated at
the Research Center. The emphasis has been on strawberry variety
evaluation in recent years. This past summer, 9 numbered selections
and about 10 varieties were evaluated. Scott a newly released var-
iety from the U.S.D.A. was evaluated for 4 seasons and will be
recommended for trial planting in Massachusetts. Several grape
varieties that show promise are Alden, Lakemont and Steuben.
******* A ******:% A A***
IV. Adaptability of apple tree rootstocks to representative or -
chard soils in Massachusetts . Peter L. Veneman
Several new rootstocks have been introduced during the last
few decades and claims pertaining to their adaptability to various
environmental conditions sometimes have been contradicting and
confusing. These claims as well as statements regarding the "old"
rootstocks (M9, M7 , M26, MM106 and MMlll) often are not based on
reliable field trials. Observations by pomologists and commercial
fruit growers indicate that local differences in soil type pro-
bably are largely responsible for variations in growth of apple
trees on particular kinds of rootstocks. An evaluation of the
effects of different environments on apple tree growth seemed
justified and several studies were initiated to research this
interaction. Following is a brief description of the various
soil- rootstock research projects and a synopsis of this year's
progress .
Size-control rootstocks are, in general, more demanding than
seedling rootstocks in respect to drainage, depth of soils and
water holding capacity. When choosing which rootstock to use it
is important to have a proper understanding of the particular
rootstock-soil type interaction. The right match between rootstock
and soil may be the difference between commercial success or fail-
ure of the planting. A wide variety of different soil types is
used in Massachusetts for growing apple trees. It is impossible
to do an experimental planting on each different soil type but the
most commonly used soils are closely related, which allows extra-
polation of the results of a limited number of research sites to
most Massachusetts and New England conditions. This project con-
sists of two stages, one of which is concerned with the carefully
monitored growth of selected rootstocks on 9 representative or-
chard soils. The second stage involves the evaluation of the
growth of the different size controlled rootstocks as related to
10.
type of soil in a large number o£ orchards throughout Massa-
chusetts .
Ten research sites have been selected, each site being
representative for a certain type of soil. The following soil
series were chosen on the basis of importance for the New England
fruit industry: Charlton, Colrain (2 sites), Paxton, Shelburne,
Wethersf ield , Woodbridge, Ridgebury, and Cabot. The first two
soil series do not have a hardpan and are well drained. The
other soils have a hardpan within 3 ft. depth and are increasingly
wetter; Paxton, Shelburne, and Wethersfield being well drained
and Ridgebury and Cabot representing the poorly drained soils.
The tree planting at each experimental site will consist of
standard type 'Mcintosh' on either M7A, M26, M9/MM106, and M9/
MMlll rootstock. Spur 'Delicious' on M7A rootstock will be used
as a pollinator. Each row will contain the four different root-
stocks at random with the 'Delicious' in the middle. Spacing
between trees in a row will be 14 ft. There will be 8 rows spaced
20 ft. apart. The planting will be established in the spring of 1982 .
Most soils at the experimental sites have already been described,
classified and sampled for physical and chemical laboratory
analyses .
During the second phase of this project a large number of
orchards are visited. Production of selected rootstocks is ev-
aluated, especially in relation to soil type. Rootstocks, in
general, seem to grow and produce reasonably well on soils with
a hardpan at depths greater than 20". This was substantiated by
observations made in the fall of 1979 at the Horticultural
Research Center in Belchertown. Trees planted in loamy soils
with a hardpan within 20" did, in general, poorly or perished;
while rootstocks in deeper, better drained soils did much better.
During the dry 1980 season, M7 rootstocks were observed to suffer
on shallow soils with a restrictive layer within 24" of the soil
surface. Tree growth and especially anchorage was poor and several
trees tipped over. Growth of MM106 on well drained Paxton soils
(hardpan within 36") was judged excellent to good even during the
dry 1980 summer.
********************
V. Effect of soil water and depth to hardpan on rootstocks .
Peter L.M. Veneman
More than 50% of the Massachusetts orchards are located on
relatively shallow soils over bedrock or are at some depth under-
lain by a hardpan. Both types of phenomena limit root penetration
and ultimately restrict tree development. High seasonal or per-
manent water tables may have the same detrimental effects on root-
stock performance. This project is an attempt to accelerate the
evaluation of the effects of soil moisture regime and depth of
11.
growth restricting layers on the performance of apple trees on
clonal rootstocks. This is accomplished by a newly developed
testing procedure under controlled conditions in a greenhouse.
The effect of a hardpan will be simulated by using growth
containers with different heights. The bottoms of the containers
will limit expansion of the root system and thus are limiting
growth in the same fashion as actual hardpans. Massachusetts
orchard soils often have growth restricting layers at 2-3 ft.
and the growth containers in this trial are, therefore, either
2 or 3 ft. deep. The containers are equipped with a specially
designed bottom which permits control of the soil moisture regime,
Three moisture conditions are possible: dry, moist, or wet.
Growth performance of each rootstock will be evaluated over a
period of time until differences become evident.
A greenhouse was erected in the fall of 1980 at the Horti-
cultural Research Center in Belchertown. The necessary experi-
mental equipment was assembled over the 1980 summer and the
current set-up allows for the simultaneous evaluation of 8 differ-
ent rootstocks. However, the greenhouse roof has yet to be
installed because of adverse weather conditions, but it is hoped
that an evaluation cycle can be started in January. That test-
ing cycle will compare the growth of 'Mcintosh' apple trees on
M7, M9, M26, MM106, MMlll and standard rootstocks.
AAA********
AN UPDATE ON FRUIT TREES INJURED IN 1978-1979.
William J. Lord
Department of Plant and Soil Sciences
Winter injury to fruit trees in 1978-1979 was predominantly
damage to roots. The cause and factors influencing the injury,
and symptoms of the injury were discussed in the JANUARY/ FEBRUARY
1980 issue of FRUIT NOTES. The majority of the weakened peach
trees were removed during the summer of 1979, but not the apple
trees. In late-summer we tagged individual limbs and whole apple
trees at the Horticultural Research Center in Belchertown after
rating the severity of winter injury. This was done to enable
us to determine the degree of tree recovery in 1980.
Lack of snow cover and relatively mild temperatures character-
ized the winter of 1979-1980. No injured limbs or trees died dur-
ing the winter. Bloom was heavy on many of the injured trees but
fruit set was very light. Nevertheless, the fruits were removed
chemically and by follow-up hand thinning.
12.
Trees severely affected in 1979 showed no signs of recovery
in 1980 and some died. Injury symptoms did not worsen on trees
having only 1 or 2 affected limbs. However, the affected limbs
produced little terminal growth in 1980.
Our experiences with the winter injury of 1979-1980 lead
us to conclude that damage to apple trees was most severe on
poorly drained soils and that recovery from injury of severely
injured trees may be slow. It appears that the best solution
to the problem is tree removal.
**********
ALTERNATE vs. EVERY MIDDLE SPRAYING FOR APPLE PESTS: 1980
RESULTS FOR ARTHROPOD PESTS AND 5-YEAR TRENDS
W,M, Coli""-, G. Morin^, N.D. Goodhue^, M. Kuzontkoski"^ , T.A. Green^'
M.R. Paul^, S. Marafino , and R.J. Prokopy
Department of Entomology
In previous issues of FRUIT NOTES, we have reported our
findings on the relative effectiveness of alternate-middle vs.
every middle spray programs for apple pests in 1976-1979 growing
seasons. (See FRUIT NOTES 42(3), 43(3), 44(3), and 45(1).
Here we present (a) our 1980 findings on alternate middle vs.
every middle spraying for insects and mites, (b) a cost-benefit
analysis with regard to insect and mite control in 1980 and (c)
a summary of pest injuries and cost-benefit analysis for a multiple
year period.
Four test blocks in commercial orchards located in the major
fruit-growing regions in Massachusetts were each divided into 2
plots of 2-6 acres. One plot received the alternate-middle pro-
gram on each spray date throughout the season. The other received
the every middle program. Each grower followed his normal spray
schedule, using an air-blast sprayer and spray materials and con-
centrations (Ix, 4x, etc.) of his own choosing. Except in one
block, all trees were fully grown; some on M7 rootstock, others on
seedling. Pruning was generally adequate to allow for good spray
penetration into tree centers.
1
Pest Management Specialist
2
Senior Field Scouts
3
Field Scouts
4
Lab Technician, Entomology Department
5
Extension Entomologist
13.
Monitoring of Pest Populations
We monitored adult populations of tarnished plant bugs (TPB) ,
European apple sawflies (EAS) and apple maggot flies (AMF) using
commercially available visual traps. In addition, pheromone
(sex odor) traps were used to monitor redbanded leafroller (RBLR) ,
oblique-banded leafroller (OBLR) , codling moth (CM), San Jose
scale (SJS) , tufted apple budmoth (TABM) and spotted tentiform
leafminer (STLM) . Visual inspections of fruit and foliage in all
portions of the tree canopy were used to monitor populations of
plum curculio (PC), green apple aphids (GAA) . woolly apple aphids
(WAA) and aphid predators and spotted tentiform leafminer (STLM) .
Mites were monitored using leaf brushing techniques described
previously .
Sampling was weekly through petal fall and tri-weekly there-
after. At harvest, an on-tree survey of 1200 fruit per treatment
block was performed to determine injury levels to fruit.
Insect Injury to Fruit at Harvest
In 1980, total insect injury at harvest averaged 0.96% in
alternate-middle blocks vs. 1.17% in every middle blocks. (Table 1)
Table 1. Average percent of insect injury to fruit in 4 alternate-
middle vs. every middle commercial orchard blocks in Massachusetts,
1980.
Insect Every middle Alternate middle
Tarnished plant bug 0.78 0.38
Plum curculio 0.25 0.15
San Jose Scale 0.00 0.20
Apple maggot fly 0.03 0.00
European apple sawfly 0.03 0.00
Green fruitworm 0.03 0.00
Codling moth 0.00 0.00
Leafrollers 0.05 0.08
Sooty mold 0.00 0.15
Other 0.00 0.00
Total % insect injury 1.17 0.96
% leaf terminals infested
with apple aphids 10.2 5.5
Avg. number of mites/lf 2.0 0.7
In 1980, TPB was the most serious insect pest in both types of
treatment blocks, although injury in each was substantially lower
14.
than the statewide average percent TPB injury in IPM or Check
blocks (1.44%). This variation in TPB injury probably relates
simply to differences in pest pressure rather than any direct
treatment effect.
Injury to fruit from several of the major insect pests (PC,
EAS, AMF, LR and GFW) was at acceptable levels, with no outstanding
differences between treatment blocks (Table 1). However, SJS
injury was higher in the alternate middle blocks in 1980, indicat-
ing the need to thoroughly apply dilute rates of oil in an every
middle treatment regime in 1981 to prevent further buildup of this
pest .
It is interesting to note that both the percent of leaves
infested with aphids and the average number of plant- feeding mites
per leaf were lower in alternate vs. every-middle blocks in spite
of reductions in pesticide use in these blocks.
Cost-Benefit Analysis
In 1980, alternate-middle spraying resulted in a savings of
$53.22 per acre for insecticide and miticide materials and $12.41
for application costs. In addition, fruit loss due to insect
injury was $10.72 less per acre in alternate vs. every middle
blocks (Table 2) .
Table 2. Cost-benefit analysis of every middle vs. alternate
middle treatments, 1980z.
Dollor cost/acre
Every middle Alternate middle Differences
Avg. cost of insecticide
and miticide materials $156.72 $103.50 -$53.22
Avg. application costs 32.22 19.82 - 12.41
Avg. value of fruit loss
due to insect injury 61.36 50.64 - 10.72
Avg. net benefit from alternate-middle spraying for
insects and mites +$76.35
-
Based on suggested retail pesticide costs published by J. Williams,
Regional Fruit Specialist: labor costs of $5.50 per hour, fuel
costs of $2.20 per acre and average yields of 550 bu/acre.
It is interesting to note that in 1980, alternate middle pro-
gram costs were not exactly one half of those of every middle pro-
gram costs. This is due to the fact that two growers applied oil
15.
and miticide sprays on an every middle basis, which resulted in
somewhat higher than expected material and application costs.
' Nevertheless growers utilizing alternate middle spraying
realized an average net benefit of $76.35 per acre in 1980.
Summary of 5-year trends in alternate vs. every middle blocks .
Overall, during the period 1976-1980, average percent injury
at harvest from insects was virtually identical in alternate vs.
every middle treatment blocks (Table 3) .
Table 3. Average percent of insect injury to fruit at harvest
and percent infestation with aphids and mites in four alternate
middle vs. every middle commercial orchard blocks, 1976-1980.
Insect Every middle Alternate middle
Tarnished plant bug 1.6 1.4
Plum curculio 0.2 0.1
San Jose scale 0.1 0.1
Apple maggot fly 0.1 0.1
European apple sawfly 0.2 0.2
Green fruitworm 0.1 0.1
Codling moth 0.1 0.0
Other 0.0 0. 1
Total percent insect injury 2.4 2.1
% leaves with aphids 7.8 8.6
% leaves with mites 8.8 (2.0)^ 11.2 (0.7)^
-
1980 data in ( ) = no. mites per leaf.
Specifically, while it is evident that tarnished plant bug is
the single most damaging pest in alternate and every middle blocks,
all the major fruit damaging insect pests appear to be equally
amenable to control using either alternate middle or every middle
spray techniques.
Table 3 also shows the average percent of leaves infested with
aphids and mites in alternate vs. every middle blocks for the per-
iod 1976-1980. During this period aphid populations were slightly
higher in the alternate middle blocks. However, there was no sign-
ificant fruit injury from aphid honeydew or sooty mold growth in
either block, indicating that aphid infestations were below economic
injury levels and would not justify the cost of additional spray
applications (data not shown) .
16.
Mite populations followed similar trends, with the exception
that, in 1980, mite numbers (given in mites/lea£) were 65% lower
in the alternate vs. every middle treatment blocks.
Three year cost-benefit analysis
While we are not able to perform cost benefit analyses on the
1976 and 1977 data owing to differences in sampling techniques and
data collection methods, we believe that the composite of the 1978,
1979, and 1980 data indicates the potential benefits of alternate
middle spraying over time.
Table 4 indicates that for the latter 3 years, growers rea-
lized a net benefit from alternate middle spraying of $41.40 to
$85.38 per acre. Although it is difficult to make comparisons
between years owing to variability in costs from year to year,
alternate-middle spraying would appear to result in an average net
benefit of about $67.00 per acre.
Table 4. Cost benefit comparison of alternate vs. every middle
spray treatments, 1978-1980^.
Cost reduction/acre due to alternate-middle
spraying
1978 1979 1980
Insecticide ^ Miti-
cide spray materials -$29.61 -$48.05 -$53.22
Spray application
costs - 8.87 - 14.22 - 12.41
Value of fruit loss
due to insect injury - 2.92 - 23.11 - 10.72
Net benefit from
alt. middle spraying +$41.40 +$85.38 +76.35
z
Labor costs: 1978 - $3.50/hr; 1979 - $5.00/hr.; 1980 - $5.50/hr.
Fuel costs: 1978 - $1.50/A; 1979 - $2.00/A; 1980 - $2.20/A
Fruit value: Variable in each year based on current market quo-
tations at harvest.
Pesticide costs: Based on Coop. Extension Service suggested retail
prices . _
The value of $67.00 average net benefit per acre compares to
an average net benefit over the same period of about $105.00 per
acre (exclusive of scouting costs) from the IPM scouting and grower
17.
advisement program. Even allowing for scouting costs of $25.00
per acre (NY presently charges $17. 00/acre) , the IPM scouting
and advisement program appears to yield a greater net benefit per
acre than the alternate middle program. Perhaps the greatest po-
tential rests in combining the IPM scouting and grower advisement
program with the alternate middle program. We introduced this
approach to orchard spraying on a limited basis in some of our
IPM blocks in 1979 and 1980, with apparent success. We hope to
continue on in this direction in 1981.
Cooperative Extension Service
U. S. Department of Agriculture
University of Massachusetts
Amherst, MA 01003
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. 46 No. 2
SPRING ISSUE 1981
TABLE OF CONTENTS
Nectarine Varieties
Erratum in January.'February 1981 issue
Root System Distribution of Highbush Blueberry
Under a Sawdust Mulch
Pomological Paragraph
Considerations in Establishing Grower-Owned
IPM Organinzations in Massachusetts
Pomological Paragraph
A Chemical Bird Repellent for Highbush
Blueberries
Research in Progress
Fruit Research in Plant Pathology
Control of Water Sprouts and Suckers with
Tree-Hold"
NECTARINE VARIETIES
James F. Anderson
Department of Plant and Soil Sciences
There is an increasing interest in the production of necta-
rines by Massachusetts growers who market their fruit through
farm stores and pick-your-own operations. In the past the pro-
duction of nectarines in this region \sias not very profitable.
This was due in part, to the susceptibility of the fruit to
brown rot and lack of fruit size. Breeding programs at Experi-
ment Stations in Canada, New Hampshire, New Jersey, New York
and Virginia and by the U.S.D.A. and several individuals have
resulted in the introduction of many new varieties with improved
size, flavor and hardiness. The development of improved pesti-
cides and application equipment has allowed for better control of
brown rot and the insects that contribute to its spread.
We have had a very limited recent experience ivith nectarine
varieties in our College orchards. We fruited Lexington, Cavalier,
Nectaheart and Nectarose for 10 or more years at the Belchertoivrn
facility, all performed satisfactorily but none of these are cur-
rently offered by major nurseries.
Nectarine varieties planted in our new orchard include Chero-
kee, Harko, Stark Early Bird, Stark Crimson Gold, Stark Sweet
Melody and 2 numbered selections, hopefully other varieties will
be added this spring.
As we have had no experience with the varieties currently
offered, the comments that follow have been abstracted from several
publications and nursery catalogs. This material is offered for
informational purposes only and does not indicate a recommendation.
The varieties are listed in order of ripening.
Nectared 1: An introduction from the New Jersey Station. Intro-
duced in 1962. Fruit is of medium size, oval in
shape and is nearly completely covered with a dark
red blush. The flesh is yellow, juicy, slightly
coarse and moderately soft. The flavor is sweet and
good. It is a clingstone. The flower buds are mod-
erately hardy and it is productive. The New York
Station considers this to be the best very early,
yellow fleshed nectarine that they have tested. Ripens
12 to 14 days before Redhaven.
Morton: Introduced by the New York Agricultural Experiment
Station, Geneva in 1965. Fruit is attractive dark red
but somewhat small in size. The fruit is white fleshed,
juicy, slightly coarse and medium firm. The flavor of
this semi-clingstone variety is very good. The tree is
hardy and vigorous. Ripens about 5 days before Redhaven,
Harko: Originated at Harrow, Canada. Introduced in 1974.
Fruit is medium in size, roundish, with a solid red
skin and a freestone. The flesh is yelloiv", medium
in firmness with good texture and flavor. The trees
are medium in size, spreading and productive. The
trees are tolerant to bacterial spot and brown rot.
Ripens 1 or 2 days after Redhaven.
Independence: Originated in Fresno, California by the U.S.D.A.
Introduced in 1965. Fruit is large, dark red over
a yellow undercolor and slightly oval in shape. The
flesh is yellow, firm, slightly coarse in texture and
the flavor is good. The stone is free. Tree is vigor-
ous, productive and about equal to Redhaven in bud
hardiness. Ripens about 2 days after Redhaven.
Hardired: Another 1974 introduction from Harrow. Fruit is of
medium size vrith a brilliant almost solid red color.
The flesh is yellow, medium- firm with good texture
and flavor. The trees are vigorous, very hardy and
very productive, requiring heavy thinning to maintain
its medium fruit size. The trees are tolerant to
bacterial spot and brown rot. Ripens 5 days after
Redhaven.
Flavortop:
Originated in Fresno, California by the U.S.D.A. Intro-
duced in 1969. Fruit is large, ovate mostly red and
a freestone. The flesh is yellow, firm and smooth,
the flavor is excellent. The tree is said to be
vigorous and productive but tender to cold and sus-
ceptible to bacterial spot. Ripens about a week after
Redhaven.
Mericrest:
Nectared 4
An introduction from the New Hampshire Experiment Sta-
tion. Fruit is medium in size, round v\rith a pronounced
suture. The flesh is yellow, juicy and has excellent
flavor. The trees are vigorous, highly productive and
tolerant of bacterial spot and brown rot. Ripens 7
to 10 days after Redhaven.
Fruit is medium in size, attractive with a dark red
blush over a yellow undercolor. Flesh is yellow, med-
ium firm and slightly fibrous in texture. The flavor
is sweet and rich. A semi - freestone. The tree is
moderately hardy and is productive, heavy thinning is
required. Ripens 7 to 10 days after Redhaven.
-4-
ROOT SYSTEM DISTRIBUTION OF HIGHBUSH BLUEBERRY
UNDER A SAWDUST MULCH
R.E. Gough
Department of Plant and Soil Sciences
University of Rhode Island
Kingston, RI
Even though vegetative and reproductive growth of plants is
very dependent on a functioning root system, relatively little
attention has been given to root system development in fruit
crops. This is certainly true of the highbush blueberry. Several
studies show that the root system of mature plants is shallow and
fibrous, but no one has studied its distribution in the soil.
Therefore, in 1979, at the University of Rhode Island we undertook
a study to determine the root distribution and general shape of the
root system of young and mature bushes of cultivated highbush blue-
berries.
Six 13-year-old Coville and five 7-year-old Lateblue bushes
were growing on a Bridgehampton fine sandy loam soil at a pH of
4.8. Bushes were spaced 6 feet x 10 feet and the entire area
within and betxveen rows was maintained under at least 6 inches of
sawdust mulch for the entire life of the bushes. The sawdust was
a mixture of hardwood and softwood and was approximately 1-year-
old prior to annual application. The water table was at least 5
feet below the soil surface. Bushes generally were not irrigated.
Each bush received an annual application of 2 pounds of 5-10-10
fertilizer.
Core samples containing roots were taken at different locations
around each bush and a trench was excavated completely beneath the
center and half way around 1 bush to determine the extent of vertical
root penetration and the regularity and the relative density with
which roots radiated from the crown.
The dripline of all bushes was located approximately 2 feet
from the crown. In all cases, the bush crown, considered to be
that area from which new canes arose, was about 16 inches in dia-
meter.
Findings
The root systems were primarly composed of fine, fibrous roots
less than 0.1 inch in diameter. They were shalloiv and formed an
inverted cone of from 11 to 33.5 cubic feet in volume. Roots tended
to be primarily oriented parallel to the soil surface with very few
noticeable vertical roots. In no case were roots found in the unde-
composed layer of mulch. Fine, fibrous roots, intermingled with larger
roots, first appeared in the upper layers of partially decomposed
mulch.
Stark SunGlo: Originated in LeGrand, California by F.W, Ander-
son. Introduced in 1962. Fruit is large, symmetri-
cal, globose with a yellow skin partly overspread
with red. Flesh is yellow with some red around the
pit, firm and the flavor is good. This freestone
variety ripens evenly and has good keeping and ship-
ping quality. The tree is large to medium, moderately
vigorous and productive. Ripens 10 to 14 days after
Redhaven.
Fantasia: Originated in Fresno, California by the U.S.D.A.
Introduced in 1969. Fruit is large, ovate, bright
red with a yellow undercolor and a freestone. The
flesh is yellow, firm, smooth and has good flavor.
The trees are productive but susceptible to bacterial
spot. Ripens about 2 weeks after Redhaven.
Nectared 5: Fruit is of medium size, 75% to full red over yellow.
Flesh is yellox\', slightly soft, juicy sweet and
good in flavor. This freestone variety is vigorous,
hardy and productive. Ripens 16 to 19 days after
Redhaven.
Nectacrest: Originated at the New Jersey Agricultural Experiment
Station, New Brunswick. Introduced in 1947. Fruit
is large, white fleshed and freestone. The flesh is
fairly firm and has a fine nectarine flavor. The
tree is vigorous and hardy. Ripens about 20 days
after Redhaven.
Stark Red Gold: Originated in LeGrand, California by F.W. Anderson.
Introduced in 1962. Fruit is medium to large in size,
skin is yellow overlaid with red. Flesh is yellow
with red around the pit, firm and the flavor is very
good. The tree is fair in hardiness, productive and
is susceptible to bacterial spot and mildew. Ripens
4 weeks after Redhaven.
There are other varieties that may be equal to or better than
the above.
ERRi\TUM IN JANUARY /FEBRUARY, 1981 ISSUE
An error should be corrected on page 8 of the January/February
1981 issue of FRUIT NOTES. In the article entitled "FRUIT VARIETY
EVALUATION AT THE HORTICULTURAL RESEARCH CENTER, James Anderson
mentioned the apple variety Akana . The correct spelling of this
variety is Akane.
-5-
The root system of 13-year-old 'Coville' plants extended in
measurable amounts up to 4 feet firom the perimeter of the crown, and
a few roots were noted regularly at distances of up to 6 feet.
Roots were recorded at depths of 32 inches on most bushes.
Overall, approximately 50^6 of the root system was located
within 1 foot of the crown, while 84^ of the root system occurred
within 2 feet of the crown, which was approximately the dripline
of the bushes.
The root system of a typical 7-year-old 'Lateblue' plant is
usually located iv'ithin less than 2 feet from the crown perimeter.
In only 1 instance were roots detected at a 2 foot distance and
these were within 11 inches of the soil surface and comprised only
0.311 of the total root dry weight for that bush. Roots v\'ere
occasionally found at depths of 32 inches within the first 1 foot
from the crown perimeter. However, most or all of the root system
(88-100%) of individual plants was located in the upper 14 inches
of soil. Virtually 1001 of the root system of these plants was
located within the dripline.
Discussion
Ihe shallo^^.' root system may be in part responsible for the
blueberry's ability to survive in swampy locations. However, the
general depth of the mature system coincides with those reported
for other crops such as apple, peach, cherry, grape and olive.
Depths can be expected to vary, however, depending upon soil type
and aeration. For example, apple roots have been reported to
penetrate to depths in excess of 32 feet in a well-aerated Nebraska
soil, while the roots of similar trees growing in deep loam soils
in California were found to penetrate to only half that depth.
Presumably, the root system of the blueberry can also vary greatly
as soil conditions are changed.
Use of mulches certainly modified blueberry root distribution.
Our finding of an absence of blueberry roots in the upper layers of
mulch is similar to a report on apple root distribution. In a study
of the effects of various m.ulches and fertilizers on yield and sur-
vival of blueberry plants, Kramer et. al , in Maryland found remark-
able differences in root distribution under peat mulch as compared
to no mulch. They reported that the roots of 2-year-old 'Pioneer'
and 'Concord' plants spread approximately 35 inches from the main
stem but were limited totally to the upper 3 inches of mulch, while
those of the control plant spread only 12 inches but penetrated to
a depth of 9 inches. They reported similar but less dramatic results
with other mulches, including pine needles, oak leaves, and straw.
This experiment indicates that the cultivated highbush blue-
berry plant posseses a shallow, fibrous root system that is primarily
distributed within the area between the crown and the dripline of
the bush. Fertilizer should therefore be placed beneath the dripline
of the bush and cultivation, if practiced at all, must be very
shallow in this area.
-6-
POMOLOGICAL PAMGRi\PH
Insect larvae entering burrknots . Low light intensity at tree
trunk level, caused by shading from the ground cover, low limbs
and/or plastic mouse guards , favors the enlargement of the root
initials on the M9 stempiece of interstem trees or on M26 rootstock.
The clusters of root initials, called burrknots, are serving as
entrance sites for insect larvae especially apple bark beetle
larvae (apple bark beetles are close relatives of the peach tree
borer) . Damage from these tree borers is occurring in Massachusetts
and other fruit growing areas in Eastern United States. The
use of mouse guards made from hardware cloth and deeper planting
of interstem trees (setting the variety/M9 stempiece union 3 inches
above ground at planting) should reduce burrknot formation and
permit better spray coverage.
9! ft -H f! it * it 9: 9; it
CONSIDERATIONS IN ESTABLISHING G ROW I: R- OWNED I PM ORGANIZATIONS IN
MASSACHUSETTS
William M. Coli
Pest Management Specialist
Entomology Department
University of Massachusetts
In November, 1980, Dr. David Ferro, Extension Vegetable Ent-
omologist and I participated in the third annual National Exten-
sion Workshop on organizing grower-owned 1PM organizations held
at Kansas City, Missouri. Our purpose in attending this meeting
was to familiarize ourselves with current model IPM organizations
in other states. This ivould enable us to present Massachusetts
growers with the numerous alternatives to implement IPM programs
in the absence of federal government funding.
At this writing, apple growers are the sole commodity group
in Massachusetts participating in an IPM program. This program,
sponsored by the Cooperative Extension Service, and funded by a
5 year USDA grant has resulted in increased interest in IPM.
Growers have asked for aid in deciding how to continue to implement
IPM when Federal funding ends in September, 1982. Thus the intent
of this article is to present a discussion of a broad range of
potential considerations and options available so that Massachusetts
growers may decide which means of implementing IPM are best for their
unique conditions.
\i}\y IPM ? Integrated Pest Management pilot programs are presently
operating in nearly every state in the union in crops as diverse as
fruit, cotton, soybeans, and alfalfa. Workshop participants agreed
that there are important short and long-term benefits from IPM and
that likely candidates for IPM are progressive farmers, farmers using
a multi-spray, calendar-based spray schedule, and crops which have
high pest control costs.
-7-
Who Should Perform IPM Scouting ? If growers are to have peace of
mind regarding pest pressures on their orchards, and if pesticide
costs (especially for insecticides and miticides) are to be reduced,
some form of field scouting is needed. This scouting may be per-
formed by the grower, by a staff person, or by someone other than
the grower or staff member.
It was the general opinion of workshop speakers that scouting
is probably best not left with growers since they are frequently
busy with other management decisions. Some capable staff person
would be acceptable provided they are free to scout when necessary
rather than as other orchard jobs permit.
Massachusetts IPM, with the institution of our "grower scout"
training appears to be unique in this regard, as the majority of
our "grower scouts" made observations with our field teams on a
weekly (sometimes more often) basis. Several "grower scouts"
scouted additional acreage in their orchards as well as indicated
their interest in continuing the scouting procedures after IPM
pilot program funds ended in September, 1982. However, most speakers
at Kansas City agreed that some outside person, whose only respon-
sibilities were scouting, is more likely to have the time and inter-
est for training in pest identification, control measures (including
alternatives) and economic threshold levels.
What is Cooperative Extension's Role in IPM ? Conference partici-
pants generally stressed that Cooperative Extension's role in IPM
is threefold. One important area is the implementation of research
programs related to IPM, including an in depth look at pest bio-
logies and life histories, development of effective monitoring
techniques and the establishment of appropriate economic thres-
hold levels (ETL) .
A second role consists of creation and operation of effective
commodity-based pilot programs to develop necessary base-line data
and demonstrate, if possible, the potential environmental and econ-
omic benefits that accrue to participating growers.
Lastly, there was unanimous agreement that Extension should
continue after pilot program funding ends to play a role with regard
to education of growers, updating monitoring methods and ETL's,
as well as training and supervision of field scouts.
It would appear that the Extension Service is best equipped to
utilize high technology (computers, weather forecasting networks,
etc.) for information gathering and dispersal, to carry out needed
research, and to coordinate an interdisciplinary approach to pest
management once pilot programs have run their course.
Several states offer scout training courses (up to 80 hrs. in
some cases) through their Extension Service. Many have an exam
-8-
(open book in some cases) leading to state certification of field
scouts, since some form of quality control is deemed desirable to
prevent farmers from hiring minimally qualified scouts.
Possible Alternative Forms of IPM Organizations After Pilot Program
Funding Ends . ^
1- IPM ceases to be implemented on any significant scale . Workshop
participants uniformly believed that this is not likely to happen
so long as growers realize potential advantages of IPM and so
long as viable alternatives exist.
2. Some private commercial entity takes over . Such entities can be
in the form of independent scouts making no recommendations, or
private consultants who make recommendations (and perhaps serve
as a supervisor of scouts hired by a group of growers for a
large number of growers). If not enough qualified consultants
or scouts are available to accomodate interested growers, pro-
blems will ultimately result and IPM might fail.
3. Creation of a grower-owned entity [Cooperative) . Where a cooper-
ative is already in existence and providing services, there is
the option to add 1PM services. It is important to keep sales
of pesticides separate from IPM services in order to maintain
credibility with growers and reduce potential for conflict-of-
interest .
Growers may choose to form a cooperative (one member-one vote,
limited return to capital, and division of earning? in propor-
tion to usage) independent of already existing supply or market-
ing cooperative in order to provide IPM services, completely
removed from pesticide sales. Such a cooperative could provide
only IPM scouting, scouting plus purchasing supplies and/or
services, or full agronomic services. A cooperative providing
only IPM services, hoivever, will have problems due to the sea-
sonal nature of the work, so the best option here is perliaps to
offer other services (leaf 5 soil analysis for example).
4 . Creation of a non-profit grower-o^vned association (incorporated
or unincorporated ). Such an entity attempts to make no income
over expenses. This type of organization typically supplies
scouting services only, with no pesticide sales or application
services and can serve as a data collecting agency for the
Extension Service, receiving technical, educational and quality-
control service in return. Once growers have the scouting in-
formation, they can either make their own decision, ask the
advice of a private consultant or ask the Extension Service.
Alternatively, a non-profit groxver-owned organization can hire
a scout supervisor who maintains extension liason, and makes
recommendations to participating growers.
-O.
Alternatives in program scope and organization . Three principal
topics were discussed.
1. Alternative geographic scopes : That is, should IPM programs
be organized (a) on an individual grower basis with each con-
tracting for IPM services independently, (b) on a county (or
multi-county) basis, or (c) under a state wide umbrella.
2. Alternative program scopes : A first consideration is to decide
whether to organize so as to cover single or multiple crops
(e.g. vegetables, apples, or both, etc.)
3. Alternative services : Once program scope has been decided upon,
it next remains to be decided whether to offer (a) scouting
services only (this has minimal risks and minimal supervisory
costs but requires a close alliance with the Extension Service
for training and interpretation of scouting reports, (b) scout-
ing plus other IPM services (spray material purchase, contracts
with aerial applicators, predator releases, etc.) or (c) IPM
services plus non-IPM services (soil testing, leaf analysis,
etc.) .
These latter two options typically require a full-time manager,
substantial capitalization and some form of democratic organ-
izational structure.
Liability considerations . Conference participants agreed that tliis
area was potentially one of the largest stumbling blocks to provid-
ing IPM services after Extension-run pilot programs ended. Several
aspects of this problem must be considered.
1. Protecting individual growers from liability (as in the case of
an independent scout injured during orchard scouting).
2. Protecting scouts or private consultants from suits resulting
from improper scouting or incorrect recommendations.
3. In the case of grower oxvned organizations (cooperative or non
profit entity) , protecting this entity from suits brought by
individual participating growers.
There are numerous options in this area such as whether to limit
liability by incorporation, best decided with advice of legal counsel
when setting up IPM organizations. Scouts (or private consultants)
can for example, be hired utilizing a service contract which specifies
the job requirements. This contract would also specify that growers
will not sue under any circumstances, whether by negligence or im-
proper recommendations. Individual growers (or grower organizations)
can then carry scouts or consultants under farm liability and work-
men's compensation insurance.
-10-
Alternatively , individual scouts or consultants could purchase
Errors and Omission insurance through private vendors. The diffi-
culty here is that costs are so high, independents would probably
find it impossible to carry adequate insurance and still make any
money.
It is apparent that there are numerous legal considerations and
optional organizational forms for growers interested in implementing
IPM practices on their farms. National Workshop participants con-
tinually stressed the need for careful planning of IPM organizations
utilizing skilled legal counsel, well in advance of anticipated
need.
**********
POMOLOGICAL PAR.'\GRAPH
The Spread of San Jose Scale Revived Interest in Dwarf Apple Trees
in the Late 1800's . The influx of San Jose scale in Massachusetts
this past season brought to mind the fact that the rapid spread of
this insect in New York State during the late 1800's was respon-
sible for one of the periodic revivals of interest in dwarf apple
trees. At that tim.e it was expected that San Jose scale would
eventually spread throughout the fruit growing areas of the state
and that the spread probably could be controlled only by fumigating
trees under tents. Since it was thought that fum.igation of dwarf
trees might be feasible, fruit growers asked the New York State
Agricultural Experiment Station to determine if dwarf apple trees
could be grown profitably in commercial orchards. U.P. Hedrick
of the New York Agricultural Experiment Station said in 1915, "Had
it not been for this apprehension of grievous disaster from San
Jose scale it is doubtful if the fruit growers would have called for
the investigation, or the Station have voluntarily undertaken it".
Fortunately for commercial apple production but unfortunately for
continued interest in dwarf trees, lime-sulfur and oil, which were
introduced between 1907 and 1910, proved effective for the control
of San Jose scale. Development of dwarf trees therefore had to
wait until another crises threatened the industry many years later.
**********
A CHEMICAL BIRD REPELLENT FOR HIGHBUSH BLUEBERRIES
F. W. Southwick
Department of Plant and Soil Sciences
It is virtually impossible to produce a crop of highbush blue-
berries in the Northeast without providing protection from birds.
Consequently, successful producers of this crop have been forced
to completely enclose plantings with netting to insure the harvest
-11-
of a major portion of the crop. Trapping, scare devices, noisemakers ,
distress calls of birds, electronic sounds, etc. are usually ineffect-
ive or so objectionable that their use is impractical or prohibited.
The use of netting is very satisfactory but its cost is excessive.
The carbamate material methiocarb (Mesurol) originated as an
insecticide by Farbenfabricken Bayer A.G. of Leverkusen, Germany.
Since the early 1970's investigators associated with the U.S. Fish
and Wildlife Service, have studied the bird repellent potential
of this chemical sprayed on sprouting seeds, grain, cherries, grapes
and blueberries, and in some cases these tests have been successful.
At the present time methiocarb has been approved for use as a bird
repellent on cherries, and in some states it has a "special needs"
registration for use on blueberries.
Since we were aware of the potential value of this bird repell-
ent for highbush blueberries but lacked data comparing its effective-
ness with protective netting, an experiment was conducted in 1980 at
the Horticultural Research Center, Belchertown, MA., within a 100'
X 150' area that contained about 40 varieties or numbered selections.
Each variety or selection was in a plot consisting of 4 or 5 plants.
Prior to treatment in early July, 16 plots were selected for uniform-
ity of growth and yield potential , and then 4 plots were randomly
selected for each treatment.
Each plot represents a different variety or selection and, there-
fore, time of fruiting ripening and harvesting ^^as variable, Neverthe
less, the results show that methiocarb is an excellent bird repellent
(Table 1).
Table 1. The influence of bird repellents on highbush blueberry
yields, 1980^.
Treatments
Dates
applied
Average plant yields (lbs.)
J
All
for each replication ^ r ep 1 i -
I n ITI TV cations
Check (uncovered) 11.94 0.42' 8,99 10,15 7.88
Methiocarb 7/11,7/31,7/27 15.16 7.00 12.02 23.63 13.95
1#/100 gals H2O
Methiocarb 7/11,7/31,8/27 16.13 18.14 8.73 12,80 13.95
2V100 gals H2O
Net covered 7/3 18.56 10.64 11.35 16.22 14.19
^The harvesting period was from 7/22 to 9/8.
^Each randomized replication was a plot of 4 or 5 plants. Each plot
contained a different variety.
Check plot in replicate II ripened 7 to 10 days earlier than all the
other plots and the crop was largely consumed by birds prior to the
initial methiocarb applications.
-12-
The yield data show that 2 lbs. of 50% WP per 100 gallons of H^O
applied 3 times at about 3 week intervals was as effective as
the 4 lb. rate and as suitable as netting from July 3 to September
8, It also appears that yield of some of the check plots (replicate
I, II and IV) which were adjacent to one or more sprayed plots was
not greatly reduced by birds. This suggests that the presence of
some treated plots in a field may tend to repel birds from unsrayed
plants in the area. The poor yield (0.42 lbs. per plant) of the
Replicate II check plot was related to its extreme earliness in
ripening. This selection was fully ripe 7 to 10 days before the
other plots and prior to the first methiocarb application on July
II. Consequently, birds had an opportunity to devour the crop from
this selection before coming in contact with methiocarb on any of
the chemically treated plots. This chance situation provides addi-
tional evidence of the effectiveness of methiocarb as a bird-repell-
ent for highbush blueberries.
Present recommendations of 2 to 3 lbs. of actual methiocarb per
acre are suggested per application where clearance for use of this
material has been obtained. A tolerance of 2S ppm on harvested
fruit is allowable and a preharvest interval of 7 days will insure
no harmful residues. No more than 3 applications per season are
allowed.
The effect of methiocarb on birds is reported to be temporary.
Ingestion of small quantities of fruit treated x^'ith methiocarb is
claimed to cause birds to become excited, slightly disoriented and
unable to continue feeding. Affected birds give off distress calls
and/or react in an agitated manner ichich conveys a warning signal
to other birds. In a 1973 Fish and Wildlife Service study, blue-
berries treated with 1 lb. actual methiocarb per 100 gallons of
water were fed to robin, starling and grackle nestlings of differ-
ent ages. Nestlings fed from 3 to 10 treated berries at one feeding
survived without any incidence of ill effects. The data from this
study indicate that feeding nestlings fruit treated with methiocarb
at recommended bird repellent levels should not influence their
long-term survival.
RESEARCH IN PROGRESS
Fruit Research in Plant Pathology
William J. Manning
University of Massachusetts, Amherst
1. Etiology of the Apple Replant Problem
Apple replant is a problem of unknown origin tiiat can affect
the growth and development of new apple trees in old orchards and
. sometimes on newly-cleared sites. Some trees decline and die in
the first season. Others survive, with varying degrees of stunt-
ing and uneven growth.
-13-
We have investigated a number of instances of the apple
replant problem in Massachusetts. At the present time we are
determining which potential pathogens are involved and planning
greenhouse work \\?ith rootstocks and seedlings to determine
pathogenicity. Future work will involve screening major root-
stocks and rootstock/scion combinations for reaction to the
agent(s) of the replant problem.
2. Biomonitoring of Fungicide Residues on Apple Leaves
As part of the Integrated Pest Management Program, we have
been developing in the laboratory a method for determining bio-
logically-active fungicide residues on apple leaves. This is
done by plating leaf discs on agar plates seeded with spores
of Gloeosporium or Saccharomyces . Zones of spore germination
inhibition indicate the relative concentrations of biologically-
active fungicide residues on the leaves. This information can
be used to predict fungicide spray timing. Limited field results
were obtained last year and more extensive data will be obtained
from field tests this year.
3. Disease Resistant Fruit Trees
Apple cultivars that are immune to scab, and varying in
their resistance to powdery mildew, rust and fireblight, have
been planted at the Horticultural Research Center in Belchertown.
These include 4 trees each of: NY613452, Liberty, Priscilla,
Sir Prize, Mac Free, Nova Easygro and Prima.
Imperial Mcintosh trees are used as disease-susceptible
comparison trees.
Pear Cultivars that are resistant or tolerant to fireblight
have also been planted. Four trees each of HW602, HW603, and
Highland have been planted. Bartlett trees are used for compari-
son.
We plan to evaluate these trees under our conditions and to
begin looking at possible differences in leaf surface microflora
between resistant and susceptible trees, as a prelude to biolog-
ical management of apple scab and other diseases.
4. New Disease Investigations Block
A new block has been established to do research on integrated
chemical and biological management of apple diseases: 15 trees
each of Cortland, Empire, Roger's Mcintosh, Double Red Delicious,
and Yellow Delicious were planted in 1978 for a total of 75 trees.
Trees are in randomized units of three, \\'ith 5 replications.
-14-
CONTROL OF WATER SPROUTS AND SUCKERS WITH TREE-HOLD*
William J. Lord and Joseph Sincuk
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 follo\Nring heavy pruning. Unfortunately, their
removal becomes more time consuming in succeeding seasons' because
of the proliferation from the stubs created by pruning. Sucker
groKth from the trunks and roots of mature seedling trees and in
plantings of M.7, M.7A and interstem trees 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.
Recently, Union Carbide Agricultural Products Company received
a Federal conditional registration for TRE-HOLD Sprout Inhibitor
A112 for control of sprout growth on bearing apples, pears and
olives and on ornamental olives, pears and crabapples.
TRE-HOLD Sprout Inhibitor A112 contains 13.2% 1-Naphthalene-
acetic acid equivalent, as the ethylester. This formulation must
be diluted before use, with either water or white interior latex
paint.
Tree-Hold diluted in a combination of water and water-base,
interior-grade, white latex paint has given good control of water
sprouts at our Horticultural Research Station in Belchertown and in
grower orchards. However, the results with our trials using Tree-
Hold to control suckers under mature Cortland and Early Mcintosh
trees on .M7 rootstocks have been disappointing. Tree-Flold was applied
under the trees on June 19, 1978, June 8, 1979 and June 4, 1980.
Sucker counts have not been made this spring but counts made in the
spring of 1980 indicated that the spray applied in 1978 and again in
1979 failed to reduce the number of suckers. The failure of Tree-
Hold to effectively control the suckers is indeed a disappointment
and we believe further trials are needed. Perhaps the Tree-Hold
should have been applied earlier when the suckers were smaller. Or
perhaps Tree-Hold is more effective for sucker control under younger
trees than with which we have been working. We certainly hope that
growers will conduct some trials with Tree-Hold for sucker control
because grower experiences will add to the information currently being
obtained.
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
latexpaint. The latex paint "marks" the treated areas and makes
the mixture more viscous, thus restricting the IIAA 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 contain a mildcwcide.
Trade Name
-15-
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
ivith 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 mixture can be sprayed on the stubs during the dormant sea-
son or when the new shoots from the suckers are 6 tol2 inches in
height. However, the most effective timing is when the suckers are
actively growing. Since the Tree-Hold mixture contains 10,000 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 the 3rd
or 4th week in June 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 appli-
cation 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.
Cooperative Extension Service
U. S. D«f>ar^m^iil ai AgriCitHm^
University of Massachusetts
Amherst, MA 01 003
Official Business
Penalty for Private Use. S300
POSTAGE AND FEES PAID
U. S. DEPARTMENT OF
AGaiCULTURE
(AGR 101)
BULK THIRD CLASS MAIL PERMH
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. 46 No. 3
SUMMER ISSUE 1981
TABLE OF CONTENTS
U.S. Apple Exports Mark 'Coming of Age'
as Volume Registers 41 -year High
Laboratory Repellency of Orchard Pesticides
to the Mite Predator Awblyseius Fallacis
Summary of Apple Growing Questionnaire
Grade Defects of Mcintosh Apples:
Strip vs. Selective Pickings
U.S. APPLE EXPORTS MARK
•COMING OF AGE' ,
AS VOLUME REGISTERS 41-YEAR HIGH
Gilbert E. Sindelar
Director of Horticultural and Tropical Products Division, FAS.
It was the year of the American apple in Taiwan as sales there
led a world-wide surge in U.S. exports, with the 1979/80 volume
hitting the highest level in 41 years. Taiwan became the leading
foreign market for U.S. apples, taking the top spot long held by
Canada. Outlook for the 1980/81 season points to another banner
year .
The 1979/80 season was the third straight strong showing for
U.S. exports and marks a "coming of age" for U.S. apples in foreign
markets .
Today, apple exports are beginning to be a factor in the market-
ing equation, with one out of 10 cartons for the fresh market moving
into export. Thirty years ago, when controlled atmosphere storage
was in its infancy, apple export markets were virtually nonexistant-
except for Canada.
The importance of export markets for U.S. apple producers has
been aptly demonstrated the past three seasons. Both 1977 and 1978
were excellent export years, with 7.9 million cartons (42 lbs. each)
moving abroad in 1977 and 7.5 million in 1978. But the 1979 season-
that ended on June 30, 1980-was even better as the equivalent of
12.4 million cartons of U.S. apples moved into export, with impress-
ive gains in all major markets being topped off by the tremendous
success in Taiwan. The 1979/80 volume to all destinations was the
largest since the 1938 season when 13.8 million cartons were exported
The final tally of the 1979/80 season revealed a gain of almost
5 million cartons-or 65 percent-over the very good showing of the
preceding season. Exports earnings totaled $125 million versus $67
million in 1978/79 as the derived unit value of export sales averaged
$10.06 per equivalent carton, compared with $8.87 the season earlier.
As the 1980/81 export season begins to shift into high gear, it
is still difficult to project export totals, especially for the two
leading markets of Canada and Taiwan, because of the volatility of
the marketplace. Although early estimates indicate a dropoff in
these two markets, gains elsewhere are expected to nearly offset
these losses. As a result, U.S. apple exports in the 1980/81 market-
ing year are forecast at 12.3 million cartons, just under last year's
1
Reprinted from February, 1981 issue of Foreign Agriculture
level. However, because of the higher- than-expected U.S. crop
this season, particularly in the Pacific Northwest, exports could
exceed this projection.
Recently, USDA estimated total U.S. sales of fresh apples-
domestic and export-at 102,4 million units (42 lb) in 1979/80.
Exports alone represented 12.1 percent of these-a sharp contrast
to the early 1970 's when exports amounted to less than 3 percent of
the total U.S. marketings of fresh apples.
Export gains this past season were widespread, with advances
of 19 percent in Western Europe, 48 percent in Central America,
35 percent in both South America and the Caribbean, and 12 per-
cent in the Middle East.
In the Far East, U.S. apple exports to Hong Kong, a key market
of long standing, rose 7 percent while those to Singapore, another
market of growing importance, expanded 61 percent.
Further brightening the picture as the all-time high of 3.2
million cartons to Canada-an increase of 600,000 from the year
earlier.
While these gains were remarkable, they were overshadowed by
the sensational performance in Taiwan. On August 1, 1979 Taiwan
liberalized its import policy for apples. U.S. exporters, mostly
in the Pacific Northwest, responded quickly, moving 3.4 million
cartons to Taiwan. Value of these sales totaled $41.6 million or
$12.26 per equivalent 42-pound carton. In the preceding five
seasons, U.S. apple exports to this market averaged a mere 134,000
cartons .
A sizable increase was expected following Taiwan's decision
to liberalize its import policy, but the final U.S. export volume
exceeded expectations. Prior to liberalization, Taiwan's limited
import volume drew fantastically high retail prices-sometimes as
much as U.S. $1.75 or U.S. $2 per apple.
With liberalization, many importers sensed an opportunity for
large profits. As a result, many newcomers entered the importing
business .
In addition, some established importers of hard goods with no
experience in handling perishables got into the market. The result:
skyrocketing imports.
Can the U.S. export performance in Taiwan be repeated in the
1980/81 season? This is perhaps the major factor in projecting the
quantity of U.S. apple exports for 1980/81. A region-by- region
survey follows.
Far East The big export question is this area centers on
Taiwan. Because of the market turbulence last season, those traders
who experienced unprofitable ventures are likely to drop by the
wayside this season. As a result, a degree of stability should
return to the market, and shipments of U.S. apples should take
a more orderly flow.
While the 1980/81 projection remains conditional at this
point, U.S. apple exports to Taiwan should be down from 3.4 million
cartons in 1979/80. Other markets in the Far East and the Pacific
should show a slight gain from the 1.6 million cartons in 1979/80.
Canada The large increase in the export volume to Canada
last season still defies pinpoint measurement. Costs may have had
a bearing on the record flow of U.S. apples to our northern neighbor,
but the most plausible reason probably rests on the fact that Canada's
per capita consumption of fresh produce is rising rapidly. The
so-called "fresh approach" seems to be catching fire there as in
many other countries around the world.
But the export projection for U.S. apples to Canada this season
is guided only by the distribution of the Canadian crop. In view
of the anticipated crop increases in Ontario and to a lesser extent
in Quebec, movement of U.S. apples will probably be somewhat less
than last season's.
Western Europe The apple crop in this area is down very slightly
to 13.4 million metric tons in 1980/81, with most of the drop occur-
ing in the southern European countries, especially Spain and Greece.
The combined crops in the three key exporting countries-France,
Italy, and the Netherlands-are almost on par with last year's pro-
duction of 4.3 million tons.
Turning to the key market countries, apple production in the
United Kingdom is expected to be about 358,000 tons, about 1 percent
below the 1979/80 outturn.
Market prices in the United Kingdom were exceptionally low this
past season. As a result, the National Farmers' Union has been
waging a vigorous campaign, claiming that the very survival of the
English apple is at stake. Charges of unfair competition against
French goldens have been denied in France.
In 1980/81, U.K. growers hope the low prices of last season
will not be repeated because of an agreement with French exporters
to limit shipments of French goldens to only the higher grades,
with bulk shipments excluded.
In 1979/80, French apples represented a staggering 87 percent
of the total U.K. imports during the v/inter months.
In Norway, the apple crop this season is expected to top last
season's total, so the opening of the import market was delayed.
However, importers remain confident that the import level will
remain high-possibly around 200,000 cartons. A small plus for
U.S. apples lies in Sweden where the commercial crop is estimated
at 33 percent below last season's output.
In total, U.S. shipments of apples to Western Europe are
expected to be the same as the 1.1 million cartons moved in 1979/80,
with the major markets being Sweden, Norway, Finland, and the
United Kingdom.
Mexico and Central America Mexico's crop loss from a severe
frost last spring has been estimated at 20-25 percent by Conafrut,
a national fruit organization. Although increased imports may
result from this shortfall, Government efforts to provide relief to
growers through higher prices could mean a lower- than-expected
import level. How much goes across the border is the most important
factor in projecting U.S. apple exports to this region.
Though still small, markets of the Central American bloc have
shown a modest growth over the past few years in purchasing apples
from the United States.
The 1980/81 outlook calls for U.S. apple exports to exceed
last season's level of 744,000 cartons.
Caribbean Collectively, the islands in the Caribbean have
been showing rather steady growth since 1973 in their takings of
U.S. apples. The generally increasing tempo of tourist traffic in
this area is largely responsible for this increase, especially in
the Netherlands Antilles and Trinidad. The trend should continue
in 1980/81 with U.S. apple exports topping the season-earlier ship-
ments of 343,000 cartons.
South America Colombia has been the shining import star in
this area. Since its import liberalization of 1976, there has been
a buildup every year in U.S. apples to this market, reaching a
high of 289,000 cartons last season.
Elsewhere in South America, the outlook is not as bright. Brazil
remains-and is expected to stay-a small market for U.S. apple exporter
while Venezuela continues as an erratic market.
U.S. apple exports to South America are almost certain to rise
substantially above the previous season's figure of 676,000 cartons.
Middle East For three straight seasons, moderate gains in
U.S. exports to Middle Eastern markets have been posted, and the
overall volume is fairly high. Last season, 1.3 million cartons of
U.S. apples were shipped to the region, with Saudi Arabia taking
about 1 million and the United Arab Emirates most of the balance.
The recent trend should continue in 1980/81.
Africa This region represents only a small slice of total
U.S. apple exports. U.S. exports to this area should approximate
last season's performance of about 64,000 cartons.
-5-
LABORATORY REPELLENCY OF ORCHARD PESTICIDES TO THE MITE PREDATOR
AMBLYSEIUS FALLACIS
1 2 2
Robert Hislop , Peter Auditore , Bonnie Weeks
3
and Ronald Prokopy
For the past four years, we have been evaluating the impact
o£ orchard pesticides on the survival of Amblyseius f allacis ,
the most important spider mite predator in Massachusetts apple
orchards (FRUIT NOTES 43(4): 5-8; 43(5): 14-18; 44(5): 6-8). In
our laboratory and field trials, we found that A. fallacis could
readily survive exposure to field rates of several key orchard
pesticides, including phosmet, azinphosmethyl , endosulfan, and
captan. However, in certain commercial orchards sprayed with
these materials, we observed occasional buildup of red or two-
spotted spider mites. We theorized that application of such
pesticides at a time when spider mites were building could actu-
ally enhance buildup by repelling A. fallacis from treated areas.
Recently, we explored this possibility of pesticide repellency
to A. fallacis in laboratory tests, and we present here our find-
ings.
Our tests were conducted in the following manner. First,
we sprayed one half of a 2- inch-diameter bean leaf disc with
pesticide and allowed the residue to dry. Next we placed 15 two-
spotted mite eggs (previously sprayed with the same pesticide) on
the sprayed half of the disc, and placed 15 unsprayed eggs on the
unsprayed half. After two hours, we placed one adult female
A. fallacis on each disc, incubating all discs for 14 days. Each
Jay during the incubation period, we recorded three types of
information: (a) the number of two-spotted mite eggs consumed by
A. fallacis (consumed eggs were replaced daily) ; (b) the location
of each A. fallacis female every two hours from 8:00 AM to 6:00 PM;
and (c) the number and location of all eggs laid by A. fallacis .
We replicated each test 14 times.
Our results are presented in Table 1. Compared with the un-
sprayed halves of bean leaf discs, the presence of residues of
phosmet, azinphosmethyl, captan, or Dikar on the sprayed halves
resulted in substantially lower consumption of spider mite eggs
by A. fallacis females. Residues of endosulfan, dodine, inert
carrier powder, or distilled water had little or no such effect.
In addition, residues of phosmet, azinphosmethyl, captan, and
Dikar resulted in substantially less oviposition and substantially
reduced presence of A. fallacis on treated sites. To a lesser
extent, this was truF ot endosulfan and inert carrier powder
residues as well.
1
Presently Research Technician, Department of Entomology, University
of California at Berkeley
2
Work Study Student, Department of Entomology
3
Extension Entomologist
Together, these results show that residues of commercially-
formulated wettable powder applications at orchard rates of
phosmet, azinphosmethyl , captan, and Dikar have substantial repell-
ent effects on A. fallacis females. This could have negative
implications for integrated pest management programs involving
biological control of spider mites by A. fallacis . For example,
summer application of any of these four materials at a time after
A. fallacis has entered the trees could affect the food supply
available to A. fallacis by rendering spider mite eggs less pala-
table, thus reducing the rate of increase in the A. fallacis popu-
lation. In addition, pesticide repellency could Torce A. fallacis
into less well sprayed parts of the tree or out of the tree al-
together, thereby allov>?ing more rapid buildup of pesticide resistant
spider mites in the well sprayed parts. Further research under
field conditions is needed to determine the true impact of pesti-
cide repellency on A. fallacis .
Table 1. Influence of pesticide residues on prey egg consumption, oviposition,
and location of Amblyseius fallacis on bean leaf discs.
Pesticide
Disc half
% prey
eggs
consumed
%
A. fallacis
eggs laid
%
A. fallacis
observed locations
Phosmet 50 WP
Sprayed
Unsprayed
38.3
61.7
24.5
75.5
31.4
68.6
Azinphosmethyl
. 50 WP
Sprayed
Unsprayed
31.2
68.8
25.7
74.3
29.6
70.4
Endosulfan 50
WP
Sprayed
Unsprayed
47.1
52.9
38.0
62.0
34.3
65.7
Captan 50 WP
Sprayed
Unsprayed
37.3
62.7
12.4
87.6
22.4
77.6
Dodine 65 WP
Sprayed
Unsprayed
51.1
48.9
55.3
44.7
55.4
44.6
Dikar 80 WP
Sprayed
Unsprayed
31.3
68.7
4.7
95.3
22.3
77.7
Inert carrier
powd er
Sprayed
Unsprayed
47.7
52.3
33.8
66.2
41.7
58.3
Distilled water
Sprayed
Unsprayed
50.1
49.9
44.7
55.3
46.4
53.6
-7-
SU^ttlARY OF APPLE GROWING QUESTIONNAIRE
William J. Lord
Department o£ Plant and Soil Sciences
We frequently are asked questions by pomologists and fruit
growers from other areas about apple growing practices in Massa-
chusetts. In most instances we think we know what growers are
doing but, this may not be true. Thus, we asked growers this
past January to complete a short questionnaire. We were pleased
that 55% of the apple grower members of the Massachusetts Fruit
Growers' Association answered the questionnaire and wish to share
the results with our readers. We have listed the questions below
and under each have summarized the response to the question and
added some comments of our own.
1. What do you consider the ideal height of apple trees on M7a or
MM106?
The tree height considered "ideal" by growers averaged 12,4
feet with 68% of the answers falling between 10 to 14.8 feet.
At our Horticultural Research Center in Belchertown, average
height of mature Delicious trees on M7 is 11.5 feet in one
block and 13 feet in another, although we believe that spur-
type trees of the same cultivar on this rootstock could be
easily maintained at 9 feet (height of central leaders) . In
contrast, tree height of 9 feet is too low for the natural
vigor of non-spur Delicious on MM106 at our Research Center
and watersprouts have been troublesome. However, we are main-
taining Idared and Spartan trees on M.7 at 8.2 feet and 9 feet,
respectively, without difficulty.
2. Do you use chemical thinners (yes or no)? If the answer is yes,
which chemical thinner do you use on Mcintosh ',
on Delicious ?
Ninety-six percent of the growers stated that they use a chemical
thinner on Mcintosh. Of those using a chemical thinner: 54% used
carbaryl (Sevin) ; 15% used naphthaleneacetamide (NAAm) ; 13% used
naphthaleneacetic acid (NAA) ; and 18% used carbaryl and/or NAAm,
carbaryl and/or NAA, or NAAm or NAA.
It is obvious that the growers prefer carbaryl for thinning
Mcintosh trees, possibly because of convenience (Delicious and
Mcintosh are usually in the same block of trees and carbaryl is
the only thinner suggested for Delicious) or because of less
risk of overthinning than when using an application of NAAm or
NAA. Nevertheless, NAAm and NAA do have some direct flower-
promoting capabilities, an attribute not shared by carbaryl, and
will thin later in the season than carbaryl.
A surprising 90^ o£ the growers used a chemical thinner on
Delicious. This certainly would indicate that at least in
some years, lack o£ fruitfulness is not a problem as frequently
mentioned with Delicious in many fruit growing areas of the
United States.
Of the growers using chemical thinners on Delicious: 85% used
carbaryl, 9% used NAA, and 61 used carbaryl or NAA , or carbaryl
or NAAm. We do not recommend the use of NAA or NAAm on Deli-
cious because following their use many small seedless fruits
may persist on the tree.
3. Do you apply a growth regulator to prevent pre-harvest drop
(yes or no?) If the answer is yes, what material do you use
on Mcintosh, on Delicious?
As expected most growers (981) used a growth regulator to pre-
vent pre-harvest drop of Mcintosh. Of them, 93% used Alar-85*
and 7% used NAA. Only 51% of the growers used a growth regulator
to prevent pre-harvest drop of Delicious, and of these, 93%
used Alar-85*, 3% used 2 , 4 , 5- trichlorophenoxypropionic acid
(2,4,5-TP), and 3% used either Alar-85* or 2,4,5-TP.
We caution growers to avoid rates in excess of 1.5 lbs. of
Alar-85* per acre (assuming 300 gallons/A of dilute spray) on
Delicious because of possible fruit size suppression and fruit
flattening. On trees where fruit size may be small, 2,4,5-TP
is suggested rather than Alar-85*. At 20 ppm, 2,4,5-TP will
reduce rate of drop for about 4 weeks. This growth regulator
is generally applied in early October before frost injures the
leaves .
4. Have you used Promalin* within the last 2 years to elongate
Delicious (yes or no)? Do you plan to use Promalin* next spring
(yes or no) ?
Forty percent of the growers indicated that they had used Promalin*
on Delicious. Of the growers that have used Promalin* 64% stated
that they plan to use this growth regulator again. Nine percent
of the growers who have not used Promalin* plan to use it, weather
permitting.
The author considers the results of Promalin* to be very unpre-
dictable under Massachusetts conditions. It can increase the
typiness of Delicious but frequently the fruit response is slight
and this growth regulator has fruit thinning capabilities if
misused.
Trade Name
5. What kind of fertilizer do you use in bearing apple orchards
(a complete fertilizer, ammonium nitrate or \\rhat)?
Fifty-six percent of the growers applied a complete fertilizer
and 301 of the growers used calcium nitrate (CaCNO,)-^.
Perhaps some growers like the convenience of obtaining and
applying a complete fertilizer rather than purchasing a "bulk"
mix containing nitrogen, potassium and minor elements such as
boron. However, cost could be reduced by using fertilizer con-
taining no phosphorous (P) since there is no evidence that our
apple trees need this element beyond what is present in the
soil .
P deficiency can reduce tree growth and yield and in several
parts of the world it has been shown to be associated with
fruit breakdown in storage. Nevertheless, there has been very
little evidence of P deficiency in fruit. In fact, Drake and
Bramlage of our Department of Plant and Soil Sciences recently
found that high levels of P in apples, especially in combination
with low levels of calcium, greatly increased breakdown of apples
during storage.
Soil applications of Ca(NO,)-, are being used to enhance the Ca
levels in fruit. Nevertheless, we have no evidence that
Ca(NO^)-;> in comparison with ammonium nitrate (NH^NO^) or pot-
assium nitrate will increase fruit Ca levels. Ca(NO^)^ unlike
NH.NO, will not acidify the soil but NH.NO^ is a more economical
source of nitrogen (N) . We believe that tne cost and the amount
of N applied to apple trees is more important than the source
except under unusual situations.
6. Do you apply calcium chloride sprays to improve the calcium level
in your trees and fruit (yes or no)?
Changes in cultural practices frequently are slow, thus it was
a pleasant surprise to note that 11% of the growers are using
calcium chloride sprays.
7. Do you have early maturing apples (yes or no)? If the answer is
yes, have you applied ethephon (Ethrel*) within the last 2 years
to advance the maturity of your early maturing apples (yes or no)?
Of the growers having early maturing varieties, 471 used ethephon
to advance their maturity.
8. Have you used within the last 2 years ethephon (Ethrel*) to advance
the maturity of Mcintosh apples (yes or no)? What % of your
Mcintosh crop was treated?
The author was surprised to find that more growers (641) were
applying ethephon to Mcintosh than to early maturing varieties.
10-
The response also indicated a rapid acceptance of this relatively
new growth regulator as a marketing tool for Mcintosh, An average
of 81 of the Mcintosh crop is being sprayed with ethephon by
the growers .
9. Have you planted Mcintosh (non-spur) apple trees on M7 or M7a
within the last 10 years (yes or no)? What tree spacing or
spacings did you use? If you were planting the same trees would
you used wider or closer spacings?
The tree spacing used by growers averaged 18 feet apart in the
row with 681 of the answers by the growers falling between 14.4
feet and 21.6 feet. Between row spacing averaged 25.1 feet with
681 of the answers falling between 20.4 feet and 29.8 feet. The
percentage of growers stating that they now would plant the trees
closer was about comparable to the percentage favoring wider
spacings, and 41''6 were satisfied with present planting distances.
Thus, it is obvious that there is no trend for close spacing of
trees on M.7 rootstock.
We have a heavy soil at our Horticultural Research Center and
tree spread of our mature non-spur trees averages from 16 to
19 feet depending upon the variety and block.
10. Do you have trees on M26 rootstock (yes or no)? What varieties?
Are you sufficiently satisfied with the trees and plan to plant
more?
Forty percent of the growers had trees on M26 rootstock and of
those that had trees on this rootstock only 39% were sufficiently
satisfied with the trees and plan to plant more.
There are probably several reasons why so many growers are not
satisfied with tree growth and fruitfulness on M26. This rootstock
reacts more to unfavorable growing conditions than those on more
vigorous clonal rootstocks. Trees within a block may be extremely
variable in vigor, with some of them weak and difficult to train.
Spur-type trees appear weak when planted on light soils, as do
Cortland and Empire on this rootstock. Trees on M26 require good
deep soils with good drainage and waterholding capacity and even
on these soils they may require temporary support or permanent
support on some sites.
A Comparison Among States
The questionnaire also was sent to Maine and Connecticut growers
by the Extension Fruit Specialists in these states. The comparisons
among Massachusetts, Maine and Connecticut growers regarding the
answers on the questionnaire are of interest, and the differences J
regarding the practices are probably due to climatic conditions and "
-11-
and emphasis given by Extension and Research personnel in these
states.
The growers from the 3 states virtually agreed on the answer to
the question concerning the "ideal" height of apple trees on M7a
or MM106. The tree height considered ideal by Connecticut, Maine
and Massachusetts growers averaged 12.6, 12.1 and 12.4 respectively.
Sevin was more frequently used in Maine than in Massachusetts for
chemical thinning of Mcintosh, but the reverse was true regarding
the use of NAAm. A higher percentage of Massachusetts and Maine
growers thinned Delicious than did growers in Connecticut.
The pre-harvest drop control practices were similar among the
growers in the 3 states except that none of the Maine growers used
2,4,5-TP for drop control on Delicious.
Only 16-0 of the Maine growers had used Promalin* within the
last 2 years to elongate Delicious in comparison to approximately
401 of the Massachusetts and Connecticut growers.
The fertilizer formulations used varied strikingly among the
3 states. An orchard mix (6-0-16 formulation) was used by 84%
of the Maine growers and none mentioned the use of calcium nitrate
(CaNO,)^. Fifty-six percent of the Massachusetts growers applied
a complete fertilizer and 30% of the growers mentioned using CaNO,.
Eighty-four percent of the Connecticut growers used a complete
fertilizer but only 51 mentioned the use of CaNO,.
Calcium chloride sprays to improve the calcium level in apple
fruits were used by only 11% of the Maine growers and 28% of the
Connecticut growers in comparison to 71% of the Massachusetts growers.
A higher percentage of Maine growers (75%) used ethephon to
advance the maturity of early maturing varieties than did growers
of Massachusetts (47%). Only 26% of the Connecticut growers used
ethephon to advance fruit maturity on early maturing varieties.
About 64% of the Maine and Massachusetts growers and 42% of the
Connecticut growers used ethephon to advance the maturity of Mcintosh.
The tree spacing for non-spur Mcintosh apple trees on M7 or M7a
used by Connecticut, Maine and Massachusetts growers averaged 16.2
feet x 23 feet, 15.7 feet x 20.4 feet, and 18 feet x 25.1 feet, res-
pectively. Some of the Maine growers indicated that they had planted
Mcintosh on M7 too closely with spacings of 9 feet x 14 feet, 10 feet
x 16 feet, 12 feet x 18 feet, 10 feet x 18 feet, and so forth. There-
fore, the average planting distance used in Maine for Mcintosh on M7
was considerably lower than that used in Massachusetts.
Slightly more growers in Maine (52%) and Connecticut (53%) had
trees on M26 rootstock than did Massachusetts growers (40%) . The
percentage of growers stating that they were sufficiently satisfied
with their trees on M26 and plan more was relatively small (averaging
30 to 39% among the states) because of dissatisfaction with tree per-
formance, or because the plantings are too young to be adequately
evaluated.
12-
GRADE DEFECTS ON MCINTOSH APPLES:
STRIP VERSUS SELECTIVE PICKINGS
1 2 "^
Henry M. Bahn , Janice O'Kelley and Glenn Morin
In a previous study o£ causes of defects on Mcintosh apples
(FRUIT NOTES, Volume 45, No. 5) we noted a large variation in
packout rates ranging from 96.7 percent to 46.6 percent. We felt
this variation was due at least in part to the fact that the 1979-
1980 samples included both strip picked and selectively picked
(picked for color) fruit. In repeating the study this past year
we separated the fruit into 2 categories: strip picked and
selectively picked apples.
Sampling Procedure
We used the same general sampling format as was employed in
the previous study. A total of 16 packing sheds were visited
between January and March 1981 and the amount of fruit packed,
cullage and the reason for culling were noted. A total of 3,930
bushels were packed and 885 bushels were culled for an overall
packout rate of 77.5 percent. The culls were inspected in the
same manner as in 1979-80 although the volume of culls in 1981
did not allow the inspector to check each apole. Depending on
the volume of culls and the length of the sampling period, the
inspector checked from 15 to 100°o of the culls to determine the
reason for rejection. An average of 69% of the culls were phy-
sically inspected. The same individual insnected the culls in
1980 and 1981.
Resul ts
Composition of defects . The cull rate and reasons for culling
were similar for 1979-80 and 1981 (Table 1). The largest differ-
ences between the years were in color and size, russeting and
"other". The large difference in the "other" category can be
traced to hail damage and to soot due to malfunctioning refriger-
ation equipment at one packing shed in 1981,
Insect and disease damage totaled 0.9% of total fruit packed
in 1979-80 and 1.0% in 1981. This indicates the importance growers
place on controlling pests and disease and of the effectiveness
of preventative measures.
1
Extension Farm Management Specialist, Food and Resource Economics.
2
Agricultural Business Management, Stockbridge School of Agriculture
3
Senior Pest Management Scout, Department of Entomology.
13-
Table 1. Composition of defects on Mcintosh apnles at grower
packing sheds in 1979-80 and 1981.
Culls showing Total fruit culled
this defect because of this defect
Defect
1979-80 1981 1979-80 1981
i'o) il) (%) (%)
Insect
damage
1.8
2.9
0.4
Disease
1 damage
2.2
1.5
0.5
Color (
US No.
1)
16.9
22.5
3.7
Size (
2-1/4'
')
46.0
34.5
10.3
Bruise
8.1
9.9
1.8
Stem puncture
9.9
5.5
2.2
Mechanical
8.1
8.3
1.8
Russeting
5.7
1.9
1.3
Other^
1.3
13.0
.2
Totals
100.0
100.0
22.2
0.6
0.4
5.3
7.5
2.6
1.2
1.7
0. 5
2.5
22.3
z
Includes limb rub, cuts and cracks.
y
Includes misshapen, bitter pit, sun scald, hail damage, rodent
damage, storage freeze and soot.
Physical damage (bruise, mechanical and stem puncture) ac-
counted for 23.71, of culled fruit (5.5% of total fruit packed)
in 1981. This is just slightly better than in the 1979-80 study.
We feel this is an area where damage could be reduced by closer
monitoring of picking, handling and grading practices.
Strip picked vs. se le ctively picked--some economic comparisons .
Separating the samples into strip picked and selectively picked
(picked for color) categories did not, as we had hoped, account
for the variation in packout rates. Although selectively picked
apples did have a higher packout rate than the strip picked (82.8%
vs. 72.6%) the variance for selectively picked fruit was greater.
Packout rates for selectively picked fruit ranged from 96.6% to
42.2% while the range for strip picked was 88.9% to 54.4%. The
large variation on the packout of selectively picked fruit was due
to one sample with considerable handling damage and another with
hail damage far in excess of what might be considered normal.
An examination of Tables 2 and 3 reveals a substantial differ
ence in lost revenue due to the cullage of apples. Selectively
picking fruit (Table 2) resulted in an additional $451.20 per acre
-14-
from undamaged fruit. As might be expected, selectively picked
apples had a lower incidence o£ culling for color, 15.11 of the
culled fruit compared with 29.3-0 for strip picked fruit. Note
that this does not necessarily mean that selectively picked
orchards had less color-rejected fruit; the pickers simply left
it on the trees while strip picked rejects were picked, stored,
graded and culled. In order to assess the economics of strip
versus selective picking, growers must consider several points
including the skill and wage rates of pickers, storage capacity
and costs, and skill and wage rates of grader /packers . The
grower must consider the cost of picking, storing and grading
the additional substandard fruit against the costs of selectively
picking.
By comparing Tables 2 and 3 the reader can note a similarity
in cullage rates for most defects other than color and size.
(Presumably selective pickers leaves more undersized apples on
the trees than do strip pickers.) In nearly every category the
selectively picked fruit has slightly fewer culls and correspond-
ingly less lost revenue due to defects.
In the area of physical damage (bruise, stem puncture and
mechanical) strip picked fruit had 241 more of total fruit culled
than the selectively picked and the additional revenue lost was
$57.60 per acre. Strip pickers may hurry a bit m.ore than selective
pickers and may thus do more physical damage. Although most growers
feel they can effectively control their pickers, they may need
to monitor them closer to reduce damage.
The similarities between strip and selectively picked fruit
damage for other categories including insect and disease damage,
russeting and "other" (misshapen, bitter pit, sun scald, hail,
rodent and refrigeration damage) are as expected since these defects
are not affected by picking and handling procedures.
Conclusion
We feel that growers have the potential to increase packout
rates, and thus net revenue, by carefully evaluating causes of
defects, determining which defects may be reduced and taking the
necessary action at the proper time to insure that less defective
fruit is picked, stored, and graded. After color and size, both
of which are difficult for the grower to control, physical damage
is the most often occurring and most expensive defect. Close
scrutiny of picking, handling and grading operations and an under-
standing of the additional costs of handling and storing defective
fruit may enable growers to increase returns by raising their
packout rates.
-15-
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Cooperative Extension Service
U. S. Department of Agriculture
University of Massachusetts
Amherst. MA 01003
Official Business
Penalty for Private Use, S300
POSTAGE AND FEES PAID
U. S. DEPARTMENT OF
AGRICULTURE
(AGR 101)
BULK THIRD CLASS MAIL PERMIT
I
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. 46 No. 4
FALL ISSUE, 1981
TABLE OF CONTENTS
Pomological Paragraph
Origin of Some Old and New Apple Varieties
Orchard Mouse Bait and The Weather
The Mediterranean Fruit Fly in Massachusetts:
Can It Happen?
What 's Happening in CA Storage Research
Tree Fruit Physiology Trials Underway at the
C.D.A. Farm of Frelighsburg, Quebec
Notes Concerning the Harsh Winter of 1980-81
FRUIT NOTES INDEX FOR 1981
POMOLOGICAL PARAGRAPH
Publications available
Proceedings of the New England Small Fruit Meetings wliich
was held at Concord, New Hampshire in January, 1981 may be
obtained by making a check payable to the University of New
Hampshire and send it to Prof. W. G. Lord, Department of Plant
Sciences, University of New Hampshire, Durham, NH 03824.
The Strawberry: Cultivars to Marketing . Edited by Norman
F. Childers. This publication resulted from the 1980 National
Strawberry Conference held in St. Louis, Missouri. The book
includes over 40 papers presented by outstanding breeders,
researchers and growers. This book is an invaluable reference
and should be included in the library of anyone interested in
the strawberry. It is obtainable from Horticultural Publications,
3906 N.W. 31st Place, Gainesville, FL 32601. The cost of $21.90
includes postage and handling.
AAA*******
ORIGIN OF SOME OLD AND NEW APPLE VARIETIES
William J. Lord and James F. Anderson
Department of Plant and Soil Sciences
There is a continuing request for information as to the
origin of both old and new apple varieties. Most of these re-
quests come from operators of farm markets who are frequently
asked such questions by their customers.
Most of the apple varieties planted in this country origin-
ated here, but the history of many is obscure and except for
varieties more recently introduced, few came into existence as
as the product of the plant breeder. Most of the varieties
originated as chance seedlings and were discovered and introduced
into cultivation by some observer or admirer of the fruit.
Mcintosh, Delicious, Wealthy, Northern Spy and Baldwin are examples
of commercial varieties that originated as such chance seedlings.
The following is a list of some of the apple varieties being
sold in Massachusetts and their origin. Where varieties have
resulted from a controlled cross between two other varieties, the
origin of such varieties is expressed by placing the letter "X"
between the parent varieties. For example, the Milton variety is
a cross between Yellow Transparent and Mcintosh.
Akane Jonathan X Worcester Pearmain. Introduced by the
Fruit Tree Research Station, Aomovi , Japan in 1970.
Also listed as TohoKu #3, Primerouge and Prince Red.
Baldwin A chance seedling discovered about 1740 on a farm in
Wilmington, Massachusetts. It was widely planted in
Eastern Massachusetts as early as 1784.
Cortland Ben Davis X Mcintosh. This cross was made in 1898,
selected in 1911 and introduced (named) in 1915 by
the New York State Agricultural Experiment Station,
(N.Y.S.A.E.S.) , Geneva
Delicious A chance seedling discovered in 1881 in Peru, Iowa.
It was named and introduced by the Stark Brothers
Nurseries in 1895.
Early Yellow Transparent X Mcintosh. The cross was made
Mcintosh in 1909, selected in 1921 and introduced in 1923
by the N.Y.S.A.E.S., Geneva.
Empire Mcintosh X Delicious. An open-pollinated cross made
in 1945. It was selected for trial in 1954 and
introduced in 1966 by the N.Y.S.A.E.S., Geneva.
Golden Originated as a chance seedling in Clay County, West
Delicious Virginia about 1895. It was named and introduced by
the Stark Brothers Nurseries in 1916.
Idared Jonathan X Wagener. Was selected in 1935 and intro-
duced in 1942 by the Idaho Agricultural Experiment
Station, Moscow.
Jerseymac New Jersey 24 X Julyred. The cross was made in 1956
and introduced in 1971 by the New Jersey Agricultural
Experiment Station, (N. J .A.E. S . ) , New Brunswick
Jonagold Golden Delicious X Jonathan. The cross was made in
1943, selected in 1953 and named in 1968 by the N.Y.
S .A.E. S . , Geneva.
Lodi Montgomery X Yellow Transparent. The cross was made
in 1911, selected in 1922 and named in 1924 by the
N.Y.S.A.E.S., Geneva.
Julyred N.J. 8 X [Melba X (Williams X Starr)]. Selected in
1955 and introduced in 1962 by the N.J.A.E.S., New
Brunswick.
Macoun Mcintosh X Jersey Black. The cross was made in 1909,
selected in 1922 and introduced in 1923 by the N.Y.
S. A.E .S. , Geneva.
-3-
Melba An open pollinated seedling of Mcintosh selected
in 1909 and introduced in 1924 by the Canada
Dept . Agricultural Experiment Station, Ottawa.
Mc Intosh Originated as a chance seedling in Dundas County,
Ontario, Canada. Propagation of this variety began
in about 1870.
Milton Yellow Transparent X Mcintosh. The cross was made
in 1909, selected in 1920 and introduced in 1923
by the N . Y . S . A. E .S . , Geneva.
Mollie ' s (Golden Delicious X Edgewood) X (Red Gravenstein X
Del icious Close). The cross was made in 1948, selected in
1956 and introduced in 1966 by the N.J.A.E.S., New
Brunswick .
Mutsu Golden Delicious X Indo. The cross was made in 1930
and the cultivar was introduced by the Fruit Experi-
ment Station, Aomori, Japan in 1948. It was intro-
duced into the United States in 1948. Called Crispin
in England.
Northern Originated as a chance seedling in East Bloomfield,
Spy Ontario County, New York about 1800.
Paulared Originated as a chance seedling. Discovered in an
orchard in Sparta, Michigan in 1960 and introduced
in 1967.
Puritan Mcintosh X Red Astrachan. The cross was made in 1929
and the cultivar was introduced in 1953.
Q uinte Crimson Beauty X Red Melba. A selection of the
Canada Department of Agriculture Research Station,
Ottawa. Introduced in 1964.
Red This is a Russian variety imported by the Massachusetts
Astrachan Horticultural Society in 1935.
Rhode Island Originated as a chance seedling probably in the
Greening vicinity of Newport, Rhode Island in about 1750.
Rome Originated as a chance seedling in Lawrence County,
Beauty Ohio before 1848.
Spartan Mcintosh X Yellow Newtown. The cross was made in 1926
and introduced in 1936 by the Canada Dept. Agr . Res.
Sta., Summerland, British Columbia.
Spencer Mcintosh X Golden Delicious. The cross was made in 1926,
selected in 1938 and introduced in 1959 by the CD. A.
R.S., Summerland, British Columbia.
Vista N.J. 77349 X Julyred. The cross was made in 1956,
Bella selected in 1962 and introduced in 1974 by the
N.J.A.E.S., New Brunswick.
Wealthy Originated in Excelsior, Minnesota from a seed of
the Cherry Crab planted about 1860.
Winter Originated as a chance seedling on a farm in Cass
Banana County, Indiana about 1876. It was introduced in
1890.
Wisconsin N.J. 148842 X PRI 187--^. The cross was made in 1956,
Viking selected in 1963 and introduced in 1969 by the Wis-
consin Agr . Exp. Sta., Sturgeon Bay.
Yellow This variety was imported from Russia by the United
Transparent States Department of Agriculture in 1890.
A*********
ORCHARD MOUSE BAIT AND THE WEATHER
Edward R. Ladd
Fish and Wildlife Service
4 Whalley Street, Hadley, MA 01035
One of the more common rodenticides used today for the control
of orchard mice is zinc phosphide (Zn,P-,). It is a dull gray
crystaline material insoluble in water and alcohol, slightly
soluble in alkalis and oil and readily degraded under various acid
conditions. Because zinc phosphide is more stable under certain
conditions than others, the question arose concerning how long it
remains effective under various field conditions.
There are several research findings on zinc phosphide which
tends to clarify the question on field stability.
1. Zinc phosphide kept in a sealed, dry condition should remain
stable for 3 or more years. Grain treated baits stored under
the same dry conditions should have a similar shelf life.
2. Grain baits placed out-of-doors under protected conditions
can remain toxic for several months.
3. The use of oils or waxing materials in bait preparations or
as an overcoating will extend the field life span of baits.
4. The major cause of loss in effectiveness of field applied baits
is the physical removal of zinc phosphide by rainfall. One
inch of rain can remove up to 601 of the toxicant.
-5-
5. Zinc phosphide eroded from the bait material decomposes
quite rapidly in soils. Wetter the sodl the faster the
breakdown.
6. Under moist, humid conditions carrier grains and other mater-
ials used to present zinc phosphide tend to mold and disinte-
grate becoming unacceptable to mice.
With all of these conditions in mind plus the knowledge that
microtus are most active on warm, sunny days the following recommen-
dations are given:
1. Pick a series of warm, sunny days to apply orchard mouse con-
trol materials. This is particularly true if material is
applied by a broadcast method.
2. Consider placing at least part of the baits under some type
of protective cover .... i . e. , a square of roofing, a board,
or 1/2 a tire to protect bait.
3. Keep a small amount of your orchard mouse bait in a dry con-
tainer. If a rain of any consequence does fall, run a
visual check on bait from several locations in the orchard.
Compare the two ; if the field applied material shows a loss
of 15-20% of its zinc phosphide coating consider re-application
where necessary.
THE MEDITERRANEAN FRUIT FLY IN MASSACHUSETTS: CAN IT HAPPEN?
Ronald J. Prokopy
Department of Entomology
University of Massachusetts
Whither the Mediterranean fruit fly? This insect, pictur-
esque to behold and s o enticing to an entomologist studying its
behavior and ecology, has for decades proven to be a devastating
pest of fruit wherever it has become established. Will it event-
ually reach Massachusetts, and if so, might it establish itself
here as a pest of our own locally growm fruits? Drawing upon
the extensive literature published on this insect (in particular
the fine article by Hagen, Allen, and Tassan in the March-April
1981 issue of California Agriculture), and upon my own research
experience with the behavior of Medflies in apricot groves in
Greece and coffee plantations in Hawaii and Guatemala, I will
attempt here to briefly describe the biology of the Medfly and to
6-
predict its future in Massachusetts.
The Medfly is a close relative of the apple maggot fly. Both
are members of the same subfamily, and both have similar behavior.
The main differences are twofold: (1) the Medfly attacks 253
different species of fruits, nuts, and vegetables, while the apple
maggot fly attacks only six, and (2) the Medfly cannot readily
survive cold conditions while the apple maggot fly can easily
overwinter in very cold regions or as pupae in the soil.
What are the principal fruits grown in Massachusetts which are
potential favorable hosts for the Medfly? The most favored one
would probably be peaches, followed (but not necessarily in order)
by nectarines, apricots, plums, cherries, apples, and pears.
Occasional host fruits include grapes, peppers, and tomatoes.
Where did the Medfly come from? It originated in tropical
West Africa, spread to north and south Africa, and then in the
1800's moved into Spain, France, Italy, Greece, and the Middle
East. It arrived in South America in 1901, Hawaii in 1907, Costa
Rica in 1955, and northern Guatemala in 1977. It has remained
firmly established in all of these countries ever since.
The first record of Medfly infestation in the USA occurred
in 1929 in Florida. Since then, it has re-entered Florida thrice
more (1956, 1962, and 1963), Texas in 1966, the Los Angeles area
in 1975 and again in 1980, and finally, in June of 1980, the Santa
Clara County area of Central California. Biochemical genetic
analysis studies suggest that the flies which entered Santa Clara
County probably came from Central or South America.
Except for this last infestation, the Medfly in the USA has
in each case been successfully eradicated through ground or aerial
application of insecticide bait sprays, aided by fruit stripping.
In the present central California outbreak, an attempt was made
to achieve eradication through a combination of sterile male
releases to render female eggs infertile (more than 100 million
sterile flies per week were released for several months), stripping
of susceptible fruits from plants, and ground applications of
malathion bait sprays. Because these combined techniques did not
prove successful, state and federal agencies have been recently
obliged to resort to the only proven method of eradicating Medflies
from substantial pockets of infestation in the USA: aerial appli-
cation of malathion bait sprays.
This article is not aimed at debating the merits of aerial
application of pesticide for Medfly eradication vs. the possible
injury that may result to those few individuals which may be highly
susceptible to deleterious effects of malathion (as with bee stings,
we can expect purely on the basis of probability that a small per-
centage of people in every population are inordinately susceptible
to the effects of potentially harmful materials entering their
system). Suffice it to say that if the Medfly cannot be contained
within its present bounds, the amount of pesticide application
then necessary to prevent fruit injury in California and possibly
other states and the amount necessary to fumigate fruit picked
from infested areas would vastly exceed the amount presently
contemplated for use in aerial bait sprays.
Why has the infestation spread so rapidly since last June
to now cover more than 1000 square miles in 3 California counties?
There may be 2 principal reasons. First, the Medfly in California
has probably undergone 4- 5 , generations of reproduction and multi-
plication since last June. Under ideal conditions, each female
can lay as many as 1000 eggs, but under normal field conditions,
each probably lays only 400 eggs or so. Thus, even though half of
the eggs were to yield males, a single fertile female by the fifth
generation could conceivably give rise to more than 300 billion
other females. Of course, given natural mortality, only a small
percentage of this possible number is actually realized. Still,
it has been enough to result in a major outbreak. A second factor
contributing to the rapid spread is the dispersal characteris 
