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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 




Official Business 
Penalty for Private Use, $300 



BULK THIRD CLASS MAIL PERMIT 



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



FN 



0100^ 



FRUITpf 
NOTES 



PREPARED BY 
DEPARTMENT OF PLANT AND SOIL SCIENCES 

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



W. J. LORD AND W. J 



EDITORS 
BRAMLAGE 



Vol. 43 (No. 1) 

JANUARY /FEBRUARY 1978 

TABLE OF CONTENTS 

Varieties of Peaches for Massachusetts 

Trends of Michigan Tree Fruit Industry (Part II) 

Pomological Paragraph 

Supplies for trellising apple trees or growing them 

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

Adult Monitoring Trap 




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 
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University of Massachusetts 
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Cooperative Agricultural Extension Work 
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FRUITpr 
NOTES 



PREPARED BY 
DEPARTMENT OF PLANT AND SOIL SCIENCES 

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

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



Vol. 43 (No. 5) 

SEPTEMBER/OCTOBER 1978 

TABLE OF CONTENTS 

New England Fruit Meetings and Trade Show, 1979 

Han/esting and Storing Apples: 
A Time for Observing Details 

Bruising of Apples After Packing 

Controlled Atmosphere Storage Safety Precautions 

Chokecherries: How to Recognize and Get Rid of Them 

Miscellaneous Information on Orchard Mouse Control 

Laboratory Toxicity of Pesticides and Growth Regulators 
to Amblyseius fallacis, An Important Spider Mite 
Predator in Massachusetts Apple Orchards 




NEW ENGLAND FRUIT MEETINGS AND TRADE SHOW, 1979 



The New England Fruit Meetings and Trade Show, as in the 

past, will be held at the New Hampshire Highway Hotel, Goncord, 

New Hampshire, The meetings are scheduled for January 10 and 11. 

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



HARVESTING AND STORING APPLES: A TIME FOR OBSERVING DETAILS 

W. J. Bramlage 
Department of Plant and Soil Sciences 

The apple harvest season is a hectic time for a fruit grower. 
His attention is often focused on his harvest labor, and perhaps 
on his harvest sales operation. And, unfortunately, something 
may have to "give". Don't let it be your storage operation! Short- 
cuts or mistakes in September can mean disaster in April. If a 
grower is to market quality fruit in the Spring, he must pay atten- 
tion to details in the Fall. Some comments follow on things to 
be watched . 



VJeather . Hot 
detrimental . 
mature apples 
coloring, esp 
to harvesting 
least 331 red 
effective sea 
period, the h 
room. Unless 
these hot app 
into storage 



weather shortly before and during harvest is generally 
It ripens fruit rapidly, leading to harvest of over- 
with shorter storage life. It results in poorer 

ecially if night temperatures are high, and again leads 
riper apples because it is necessary to wait for at 
color. It increases susceptibility to scald, making 

Id treatments crucial. If it's hot during the harvest 

ot apples increase the heat load going into a storage 
ample refrigeration is available, it is best to allow 

les to cool overnight in the orchard, and bring them 

early the next morning. 



If the weather is cool during harvest, the prospects for high 
quality fruit in the Spring are much better. Nevertheless, there 
is need to get apples off the tree and into storage as quickly as 
possible. The riper the fruit at harvest, the shorter is its 
storage life. 



With 
about 28° 
are fully 
("bruises 
to about 
damage oc 
thaw. If 
the apple 
softening 
age. If 
of time; 



late varieties, freezing may occur. Apples freeze at 
F. If they freeze, do not pick or handle them until they 

thawed . Physical contact will produce visible damage 
") when they thaw. Unless the fruit temperature falls 
22°F, apples will survive freezing; at about 22°F,'' lethal 
curs and they show browning and breakdown soon after they 

browning and breakdown do not show up soon after thawing, 
s have survived the freezing. However, any freezing causes 

and probably leads to faster deterioriation during stor- 
apples freeze, do not attempt to store them for long periods 
dispose of them as quickly as possible. 



Fruit maturity . Maturity is the stage of development at harvest. 
If too immature at harvest, fruit will never develop top quality 
flavor and may be more subject to shriveling, scald, bitterpit and 
browncore after harvest. If overmature, fruit will deteriorate 
quickly and be more subject to softening, breakdowns and rots. 

How to identify maturity is a difficult question. Pressure 
test, color (especially undercolor), abscission, and flavor are 
helpful guides, but experience with your own fruit may be your 
best measure. Use of growth regulators has made this an even more 
difficult question. Alar* delays maturity, but not as much as 
many people think. Its phenomenal drop control capability and its 
delay of softening can be misleading. Do not delay harvest of 
Alar*-treated fruit ; a significant amount of the firmness difference 
between Alar*-treated and untreated fruits will disappear rapidly 
during storage. Ethrel* hastens maturity, and despite our belief 
that Ethrel*-treated fruits can be stored if^ harvested at the right 
time, we think that it's hazardous to try to CA-store Ethrel*- treated 
apples commercially. The hormone-type Stop-drop sprays also promote 
maturation, and should be used with this understanding. 

Further complicating the maturity problem is the use of red 
strains and dwarfing rootstocks. Since for marketing reasons har- 
vesting is usually gauged by red color, the red strains are prob- 
ably an advantage to proper storage management since less mature 
(and longer keeping) fruit may be harvested. However, among the 
strains of 'Delicious' it is well known that some red strains mature 
well ahead of others. Therefore, it cannot be assumed that red 
strains are just like the standard strains except for color; other 
criteria must also be watched. It is very likely that some root- 
stocks influence maturity, although this must yet be defined. Again, 
you cannot assume that fruits from dwarf ing-rootstock trees are 
the same as those from seedling -rooted trees. You must watch these 
fruits closely. 

Just when to harvest apples for maximum storage life is perhaps 
the most frustrating question to face. In Massachusetts, flesh 
firmness of at least 15 to 17 lbs (if Alar*-treated, 16 to 17 lbs) 
is considered essential for 'Mcintosh' if they are to be stored in 
CA. If you are using a pressure- tester to gauge fruit maturity, be 
sure you are using it properly . (See: "The Use of a Pressure Tester 
to Measure Firmness of Apples''. Fruit Notes , March/April, 1977). In 
Michigan, a simple test has been~devised to measure the amount of 
ethylene gas being produced by apples as a means of determining 
whether they are suitable for long-term or for short-term storage, 
and it is being used commercially there, but we as yet have no per- 
sonal experience with this test in Massachusetts. 

Most of the problems due to harvesting slightly immature apples 
can be dealt with, and these fruit will have the potential for long 
storage. Most of the problems due to harvesting overmature apples 



* Trade Name 



cannot be dealt with except by rapid disposal o£ them. It is 
better to pick a little too soon than a little too late . Over- 
naturity is perhaps the greatest source of storage problems . 

P re-storage operations . It is absolutely essential that apples 
be cooled quickly and thoroughly after harvest. Ideally, they 
should be cooled to 32°F within 24 to 36 hours, but in practice 
it is sufficient to completely cool them in 7 days. However, few 
growers have any idea what the temperature of their fruit actually 
is in storage. (Air temperature is a poor gauge of fruit tempera- 
ture.) Some growers who have measured fruit temperature during 
storage with thermocouples have been shocked to learn how slowly 
they are cooling. Many refrigeration systems are designed to 
maintain temperatures after the apples are cool, and therefore do 
not have the capacity to rapidly cool large volumes of fruit. 
These rooms can only cool fruit adequately if they are loaded slowly 
and carefully. Use of bulk bins increases the cooling problem, 
since contact of moving cold air with the fruit is reduced. Fur- 
thermore, bins are often arranged in the storage without regard 
for air-flow patterns. Cold air must move over the surface of an 
apple if it is to cool quickly. Inadequate cooling is undoubtedly 
a major source of storage problems . 

Varieties susceptible to scald should be treated with an 
inhibitor before storage if they are to be stored beyond early 
January. Postharvest dips are very effective if used properly. 
Diphenylamine, at 1000 ppm for Mcintosh, 1000-1500 ppm for Delicious, 
and 2000 ppm for Cortland, is generally the preferred inhibitor 
except for Golden Delicious, but Ethoxyquin at 2700 ppm may also be 
used. Tests in New York indicate that liquid-concentrate DPA is 
more effective than wettable powder DPA, since it is more stable in 
suspension and less toxic to the fruit, although it requires addi- 
tion of a defoaming agent. Surveys in New York revealed that many 
dip tanks contained considerably less inhibitor than recommended, 
due to dilution of solution by wet apples, removal of inhibitor on 
the surface of treated fruit, and breakdown of inhibitor in the dip 
tank. New York recommendations now suggest that when DPA dips are 
being replenished (brought back to volume), double- strength solution 
should be added to the tank, to compensate for this diminished con- 
centration of the inhibitor. 

If a postharvest dip is being used, it is wise to add a fungi- 
cide. A circular on "New England Suggestions for Postharvest Fruit 
Rot and Storage Scald Control" is available from your Regional Fruit 
Specialist. Benlate* has given excellent decay control on apples, 
but it should be noted that Benlate* seems to be unusually conducive 
to development of resistant strains of fungi. If Benlate* has been 
used during the growing season, there is a possibility that a resis- 
tant strain is present on the fruit. Furthermore, it is suggested 
that treated fruit be removed from the dipping area as quickly as 
feasible to avoid buildup of resistant spores. Much can be done to 
reduce storage decay problems by preharvest sanitation treatments; 
this was carefully described in Fruit Notes by Dr. C. J. Gilgut in 
1972 (Fruit Notes, Sept .-Oct. :pp 2-7) . 



-4 



If a postharvest dip is used, calcium chloride (CaCl^) may also 
he added to the solution. Adequate calcium levels in the fruit are 
essential for long storage life. If calcium treatments have not been 
applied during the season, or if significant amounts of cork or 
bitterpit are present in the fruit, 24 to 32 lbs of CaCl^/100 gallons 
may be added to the dip solution. The calcium residue oft the surface 
of the fruit will continue to enter the apples during storage, and 
can substantially reduce the development of fruit disorders. 

Storage operations . CA rooms should be filled and sealed as quickly 
as the apples can be thoro ughly cooled . The longer the fruit remain 
in air after harvest, the less benefit CA will have on them. It 
should be no more than 2 weeks between the time you start loading 
a room and when that room is sealed. However, to accomplish this 
you must have sufficient refrigeration capacity in that room to ' 
remove the field heat, or else have a special room with extra cooling 
capacity m which you do the initial cooling of the fruit. If you 
must choose between thorough cooling and early sealing, choose 
thorough cooling . Don't overload your cooling capacity to get an 
early seal. 

The exact temperature at which you store your fruit is a criti- 
cal factor in determining how well they will keep. You must have a 
highly reliable, calibrated thermometer in the storage room, and 
you must store the fruit a_t the recommended temperature, not near 
It. A storage temperature that is only 1° or 2°F above the recom- 
mended temperature will significantly reduce the storage life of 
your fruit. 

Traditionally, a relative humidity of 90 to 95% has been recom- 
mended for apple storages. It has been clearly shown in recent years 
that if the R.H. is very near 1001, apples are more subject to break- 
down disorders; on the other hand, if R.H. is below 90% the apples 
will shrivel. However, we know of no storage that is equipped to 
monitor R.H., and doubt if very many storage operators ever measure 
R.H. (a slmg psychrometer is a good tool for measuring humidity). 
In this situation, we feel that storages are more likely to have too 
low humidity than too high a humidity, since it is not easy to 
maintain an atmosphere close to 100% R.H. Therefore, we recommend 
that storage operators do everything possible to maintain as moist 
an atmosphere as possible in the storage. 

For CA storage, our recommended conditions are the same as in 
recent years. Mcintosh and Macoun should be stored at 1% 0. , 5% CO?, and 
38°F. Baldwin, Delicious, Empire, Golden Delicious, Idared, Northern 
Spy, Rome Beauty, and Spartan should be stored at 3% 0^, 1% COo, and 
32°F. Cortland may be stored under either regime, but store best as 
part of the latter group of varieties. 

Careful observations and record keeping do not end with attain- 
ment of the CA condition. Atmosphere and temperature should be 
monitored and recorded daily. If the 0, falls below 3%, it should 



be brought back up immediately . Storage conditions should be 
watched closely and recorded. (The gas analyzer, the aspirator bulb, 
and all sample lines should have been carefully checked before seal- 
ing, and any indication of malfunction during storage should be 
checked-out immediately. Porous aspirator bulbs, which result in 
higher O2 readings than actually exist in the room, have been respon- 
sible for severe low O2 injury to fruit.) It is well to sample fruit 
periodically during the storage season. (See: "The Soft Mcintosh 
Problem", Fruit Notes, Sept. -Oct. 1974: pp. 1-4) 

Successful storage operation requires attention to details, 
from the beginning of harvest to the sale of the last apples. Any 
mistake or oversight can be disastrous, especially with the trend 
to longer storage periods: the longer apples are kept, the more 
important are the details. The successful operator should recog- 
nize a problem as it develops, and adjust his marketing practices 
accordingly. For example, if cooling in some fruits has been inade- 
quate, these fruits should be disposed of as quickly as is feasible. 
Long-term storage should be attempted only with apples that have 
"everything going for them". Long-term CA does not correct mistakes; 
it only underlines them. 



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



BRUISING OF APPLES AFTER PACKING 

W. J. Bramlage 
Department of Plant and Soil Sciences 

Dr. George Mattus has been conducting extensive studies in recent 
years on the condition of apples in the distribution centers and 
retail stores of Virginia. He has often observed a great deal of 
impact bruising on apples, indicating damage that is occurring during 
handling of the packed fruit. To determine some of the factors 
associated with this bruising and to try to find ways of reducing 
it. Dr. Mattus conducted a series of tests this Spring that pro- 
duced some impressive results. Some of his findings are reported 
here. 

In one series of tests, carefully harvested apples of 5 dif- 
ferent cultivars were packed in fiber or foam trays, which were 
packed in cartons. Both 88- and 100-size packs were tested. In 
addition, 6 different cultivars were packed in 3- lb poly bags, 
which were placed in 12-bag cartons. Two different cartons for 
the bags were tested: 1 carton had 12 single cells, 1 for each 
bag, whereas the other carton had only 4 cells, so that 3 bags 
were packed in each cell -- 2 vertically and 1 horizontally. 

Each carton was dropped once , from either a 6- inch or a 12- 
inch height. Injury to the fruit was tabulated and is shown in 
Table 1. 



TABLE 1. BRUISING OF APPLES, PACKED IN TRAYS OR POLY BAGS, 
FOLLOWING A SINGLE DROP OF A CARTON. 



DAMAGE TO FRUIT 



Sq . cm . 

Packing Height „ -.^ !J°-.°^ of bruised %with 

variable o£ d?op t ^^^^ bruises area per cuts or 

^ bruises per apple apple punctures 



CARTONS CONTAINING TRAYS 



Type of Tray 



Fiber 6" 64 0.9 62 

Foam 6" 52 0.7 42 

Fiber 12" 70 1.0 116 

Foam 12" 54 0.7 54 



BAG-MASTER CARTONS 



No. of Cells 



12 6" 68 1.1 109 2.9 

4 6" 69 1.2 127 2.2 

12 12" 77 1.4 223 3.5 

4 12" 80 1.5 240 4.0 

The results dramatically demonstrate the potential for damage to 
fruit after packing. A single 6 -inch drop of a carton (measure it!) 
bruised over 50^ of the fruit . Apples packed in foam trays bruised 
less than those packed in either fiber trays or poly bags. Apples 
packed in poly bags, rather than in trays, received more bruises 
from the drop, and these bruises were much larger than those on 
tray-packed fruit. In addition, the apples in poly bags received 
cuts and punctures from the drop, even the one from only a 6- inch 
height. 

Interestingly, the 12-inch drop was not much worse on the 
fruit than the 6-inch drop. Also, it made little difference 
whether the poly bags were packed in 4-cell or 12-cell cartons. 

In another series of tests. Golden Delicious apples in either 
fiber or foam trays were packed in a number of different ways to 
find out more about what influences bruising. In these tests, the 
cartons of apples taken directly out of cold storage were all 
dropped once from a 12-inch height. 



Results are shown in Table 2. These tests shcv/ed that (1) 
more injury occurred in dry fiber trays than in moist fiber trays; 
(2) more injury occurred in shallow fiber trays than in deep-cell 
fiber trays; (3) damage to fruit packed in fiber trays can be 
reduced by individually wrapping apples in paper, padding the 
bottom of the carton, and especially by putting pads between layers; 
and (4) cold apples are more subject to bruising than are warm 
apples . 

Clearly, the way apples are packed influences the amount of 
damage inflicted by impact upon the carton. However, the clearest 
m.essage from these studies is: Don't drop cartons of apples! 

TABLE 2. EFFECTS OF MODIFICATIONS OF TRAY PACKING ON BRUISING 
OF GOLDEN DELICIOUS APPLES AFTER DROPPING A CARTON 
OF 100-SIZE TRAYS 12 INCHES. 



DAIvIAGE TO FRUIT 



Packing 
variable 


% with 
bruises 


Dry fiber trays 
Moist fiber trays 
Foam trays 


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 
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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 PLAN