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Full text of "Fruit notes"

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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 



Volume 50 No. 1 
WINTER ISSUE, 1985 

Table of Contents 

Fruit Notes Subscription 

The Tree-Fruit Industry in the United Kingdom: 
Changing to Survive 

Pomological Paragraph- 
Performance of I nterstem Trees 

A Report on the 1984 Apple IPM Program 

Pomological Paragraph— 

Spur-type Trees Can Reduce Pruning Time by 60% 

Reducing Winter Injury to Tree Fruits 

Variables Influencing Size of Apple Trees, 
and Suggested Tree Spacings 

Bud Blast, Canker, and Dieback of 
Young Apple Trees in Massachusetts: 
A Progress Report 



issued by the Cooperative Extension Service, E. Bruce MacDougall, Dean, in further- 
ance of the Acts of May 8 and June 30, 1914; United States Department of Agriculture 
and County Extension Services cooperating. The Cooperative Extension Service offers 
equal opportunity in programs and employment. 




FRUIT NOTES SUBSCRIPTION 



To subscribe to FRUIT NOTES complete and mail the 
following form with your check for $3.00 (Canadian subscri 
hers, please send a U.S. postal money order). 



Wi 1 1 i am J . Braml age 
Editor 



Name 



Mailing Address 



Town, State, Country Zip 

Make checks payable to: FRUIT NOTES ACTIVITY ACCOUNT 

Send subscription form and check to: William J. Bramlage 

Department of Plant and Soil Science 
French Hall 

University of Massachusetts 
Amherst, MA 01003 

1985 



THE TREE-FRUIT INDUSTRY IN THE UNITED KINGDOM*: CHANGING TO SURVIVE 

William J. Rramlage, Department of Plant and Soil Sciences, 

and 

John Turnbull, National Fruit Adviser, ADAS, East Mailing Research Station, 
Kent, England 

To understand the forces that are producing radical changes in the tree- 
fruit industry in the U.K., it is necessary to recognize England's 
geographical and political position. Geographically, the industry is 
located at about the same latitude as Newfoundland, which places it at the 
northern edge of a climate that will support commercial production. Many 
common varieties of tree fruits cannot he grown commercially in this 
cl imate. 

Politically, the U.K. belongs to the European Economic Community (EEC), 
which allows goods to move into the U.K. duty-free from other EEC 
countries. Since some of these countries, especially France and Italy, 
have climates much more suitable for tree-fruit production, European fruits 
can often be sold on British markets at lower prices than for those grown 
in the U.K. 

The U.K.'s entry into the EEC put its tree-fruit industry in jeopardy 
and resulted in major changes within the industry. Pint of the story can 
be seen in the industry's statistics. Over the past 1") years, total apple 
acr-'age has declined 30%, pear acreage 'las declined ?.S . and cherry acreage 
has declined 50%. For plums ■'he decline is even more startling if you look 
back further: acreage in 198? was only 30% of that in 1957. Approximate 
acreage for these crops in 1983 was: apples, fi?,400 acres; pears, 10,000 
acres; plums, 8,750 acres; cherries, 3,050 acres. Peaches arp not grown 
commercially in the U.K. 

These figures may imply that this is a failing industry, but the U.K. 
fruit industry is not dying. It is adapting to new conditions to shedding 
itself of unwanted fruit or economically nonviable orchards, and adopting 
new methods to increase productivity and efficiency. These changes have 
been greatest for apples, which represent the strongest as well as the 
biggest component of the industry. Total apple production in 1982 was 
about ?? million bushels, and the ways in which apple production has 
changed will be emphasized here. 

Because of the EEC competition, the U.K. must produce what its market 
wants and the rest of the EEC cannot produce more efficiently. For apples 
and pears, this has meant concentrating production on a handful of good- 
quality varieties, all of which have been grown for more than 100 years. 



*The United Kingdom (U.K.) consists of England, Scotland, Wales, and 
Northern Ireland, although most of the tree fruits are grown in England. 



-2- 



Cox's Orange Pippin (Cox) now makes up 5fi% of the U.K. dessert apple pro- 
duction, while Bramley's Seedling (Bramley) represents 80% of the culinary 
apple production and over 40% of the total apple production. (Note: 
Bramley's are sold for processing, but there is no major apple processing 
industry in the U.K. Culinary apples are ones grown specifically for 
cooking and to a large extent are sold directly to the consumers). 

For pears, 73% of the production in 198? consisted of a single variety. 
Conference, with most of the remainder being accounted for by Doyenne du 
Cornice. These three varieties -- Cox and Bramley apples and Conference 
pears -- are ones sought by the U.K. market and not grown in Southern 
Europe. The industry will likely concentrate still further on the produc- 
tion of these varieties. 

The past 10 years have seen drastic changes in the way English apples 
are produced. The traditional orchard of large, widely spaced trees 
growing on a carpet of grass has virtually disappeared as a viable commer- 
cial entity. The framework of the trees was first drastically lowered with 
a chain saw, and strips of grass under the trees were killed with her- 
bicides. Later, these trees were replaced by small, staked trees planted 
more intensively and often grown on bare soil. A driving force in these 
changes has been the inherently low productivity of Cox trees, which makes 
increased productivity per acre critical to economic sii^vival. It is esti- 
mated that the average Cox orchard produces 225-250 bushels per acre (but 
this includes nonbearing trees), that 500 bushels per acre are needed for 
economic viability, and that '■his figure will soon rise to 750 bushels per 
acre. (Most-efficient producers are already obtaining these yields). 

To achieve such yields intensive production is required. It is easy to 
look across the English Channel to the Dutch apple industry and try to 
adopt their techniques. However, 66 to 70% of Dutch fruit farms have less 
than 10 acres of trees, while 80% of the U.K. fruit farms exceed 25 acres 
of trees. Thus, most English growers cannot afford the detailed attention 
to tree development that is given by Dutch growers and U.K. orchards are 
developing differently from better-known Dutch orchards. 

The most common rootstock for English Cox apples is MM106, although M9 
is being used increasingly. For Bramley, MM106 was also widely used but 
its use is now declining and M26 and M9 are becoming increasingly popular. 
Single-row planting at a density of about 300-400 trees per acre is most 
common, with trees trained to a central leader but restricted to no more 
than 10 to 15 feet (or preferably less) in height. 

There is considerable interest in 3-row bed plantings, trained to the 
North Holland spindle-bush system. However, there are some clear limita- 
tions to its successful adoption. fl) The size of most English orchards 
limits attention to development of individual trees. (2) Many orchards 
are frost-susceptible, and if a crop is lost or severely reduced by frost, 
the high vigor produced that year makes the growth much harder to control. 



(3) Many orchards will requi ree irrigation because their soils are too 
shallow and susceptible to drought. Therefore, for the forseeable future 
most English orchards will probably continue to employ single-row central 
leader production systems, while only the very specialized producers will 
adopt the more intensive bed systems. 

Most U.K. planting stock is certified virus-free, true-to-name, and 
true-to-clone. It is produced under the "Plant Health Protection Scheme" 
in which virus-free "nuclear stock", or mother trees, are produced at 
government laboratories and provided at nominal cost to "Special Stock" 
nurserymen who mass-propagate them for commercial sale. Growers can buy 
different grades of trees, the grade and price representing how far removed 
the trees are from the original nuclear stock. These virus-free trees are 
up to 30% more productive than virus-infected stock. 

Orchard restructuring was boosted in 1QR2 when the British Government 
introduced its "Orchard Replant Scheme" under which growers can be sub- 
sidized for orchard replanting. The plan is linked to an EEC prohibition 
against expanding the area devoted to apple production, since apples are 
overproduced in EEC countries. fEach year EEC countries dump under subsidy 
twice as many apples as are produced in the U.K.). 

Under the plan a grower can be subsidized for 22.5% of his capital 
investment in a new orchard if (1) he can provide evidence that he has 
first grubbed an area of equal size, (?.) he uses only certi fied-vi rus-free 
trees, and (3) he plants only eligible varieties: Cox, Rramley, and 
Spartan apples, and Conference and Cornice pears. (However, 25% of the 
planting can be of other varieties inserted as pollenizers.) This 
replanting subsidy can increase the 32.5% of the total capital investment if 
the entire farm has a development plan acceptable under EEC policies. This 
plan has provided a big boost to changeover of unprofitable orchards. 

The appropriate soil management system for U.K. orchards has become a 
matter of controversy. The standard system over the past 20 years has been 
the use of herbicide strips under the trees, leaving grass alleyways. In 
recent years pomologists have been advocating application of herbicides to 
the entire orchard floor, and many orchardists now employ this "overall 
herbicide" soil management system. Overall herbicide usage can increase 
soil acidity, lower soil nitrogen level, and produce phosphorus deficiency 
in apples, which increases storage losses of fruit. It can also cause soil 
erosion, although this is not a serious problem in most relatively-flat 
English orchards. The biggest concern is still another effect -- loss of 
soil structure. Soil compaction from rain and machinery can cause soil 
structure to collapse and cause a soil cap to form, which reduces water 
infiltration. Failure to return fresh organic matter can deplete soil 
organic matter, and reduction of the earthworm population can reduce water 
infiltration. On the other hand, overall herbicide usage increases yield 
10 to 20%, and the increase in fruit size is especially welcome for Cox, 
which are often small. Therefore, considerable effort is being applied to 
deal with the problems created by overall herbicide usage, rather than 
abandoning it. 



-4- 



Growth regulators are less extensively used in the U.K. than in U.S. 
orchards. For fruit thinning carbaryl is used almost exclusively -- when 
thinning is needed. Alar* is used hardly at all because it has adverse 
effects on size and storage quality of the fruit, especially Cox. In most 
cases no alternative stop-drop spray is used because red color is generally 
not important for English apples. There is essentially no use of Promalin* 
in the U.K. but some growers are using a gibberellin mixture to improve 
fruit finish of Cox. There is strong interest in potential use of the new 
growth regulator PP333 (paclohutrazol ) to suppress vegetative growth as an 
aid to controlling tree vigor in intensive production systems. 

Integrated Pest Management (IPM) is established in the tree fruit 
industry. Its emphasis is on allowing beneficial predators to build up in 
orchards, and private advisers provide guidance to growers on pesticide 
usage. Mildew, scab, and canker are the most serious disease problems, and 
red spider and caterpillars are the most troublesome insects on apples. 
Rust mite and psylla are the leading insect problems on pears. Fireblight 
is an increasing worry, especially because it can build up in the hawthorn 
hedges that are very common in most apple growing areas. 

Calcium chloride sprays are very widely used, primarily to reduce bitter 
pit of apples, and many growers also apply phosphorus sprays early in the 
season to reduce the occurrence of disorders during apple storage.' 

Harvesting is done with local labor. The small tree size that is main- 
tained allows picking from no more than short ladders. Pickers are usually 
paid a daily rate plus a bonus for picking skill. 

Storage, packaging, and marketing of apples and pears is highly centra- 
lized. Although some growers operate independently, most contract with 
large privately owned companies to store and pack their apples and pears. 
This centralization has aided the adoption of highly sophisticated storage 
technology, which in turn had had an enormous impact on length of the 
market season and quality of the stored fruit. Fruit analysis is used to 
determine the storage potential of fruit and is widely used. The analysis 
is carried out by the advisory service A.D.A.S. /M.A.F.F. , and is paid for 
by the growers. 

The costs of producing fruit in England were revealed in an economic 
analysis conducted in 1Q8?. To establish a typical orchard of Cox on M9, 
trees cost the equivalent of about $3,000 and stakes about $1,600 per acre. 
Annual costs of an orchard in full production were estimated to include 
$ 450 for pest control, $ 150 for pruning, $ 75 for herbicides, and $ 50 
for fertilizer. In contrast, the cost of storage (including prestorage 
treatments) was $?,500 per acre. Thus, it was concluded that 70% of the 
annual cost of producing these fruit was incurred after the fruit left the 
tree! A high packout rate is essential for financial survival. 



*Irade name 



-5- 



Little has been said here about pear, plum, and cherry production 
because these crops have not undergone the technological evolution that has 
occurred during the last decade for apple production. However, mention 
should be made about the decline of the stone fruit crops illustrated in 
the statistics quoted earlier. 

Decline has occurred for several reasons. One is EEC competition, which 
places fruit from Southern Europe on the market early at competitive 
prices. Plums have also been devastated by loss of demand for processed 
products. (Purchases of fresh fruit and vegetables have increased greatly 
in the U.K. during the past 20 years). Another problem is severe infesta- 
tions from plum pox -- a virus disease -- and bacterial canker, which have 
been difficult to contain. Finally, bird damage has caused severe losses; 
at present, the most common control measure is use of mechanical scare 
devices, which lose effectiveness quickly. 

The British cherry and plum industries remain in jeopardy. 
Nevertheless, there is hope that effective size-controlling rootstocks will 
be found -- some promising cherry rootstocks are presently being planted -- 
and that growth regulators, especially PP333, will suppress tree vigor so 
that intensive production methods can be employed to reduce unit costs. 

The U.K. fruit industry still has its problems but there is a deter- 
mination to tackle them and meet the challenge of competition from abroad. 
Despite economic constraints there is increasing collaboration within the 
industry, particularly in regard to research, development, and marketing. 
This cooperation is helping to streamline the U.K. fruit industry, which is 
essential for its longterm wellbeing. 



POMOLOGICAL PARAGRAPH 

Wil 1 iam J. Lord 
Department of Plant and Soil Sciences 

Performance of Interstem Trees . It is becoming increasingly apparent that 
unless well -grown trees are obtained from the nursery and/or unless they 
receive a high level of management in the grower orchard, the growth and 
early productivity of interstem trees are apt to be disappointing. Also, 
we are finding it difficult to maintain a strong central leader on 
interstem trees without staking. Under the management that is provided in 
most of our orchards, we need trees on rootstocks that will produce satis- 
factory growth and yields in the absence of optimum growing conditions and 
care. Thus, interstem trees are not recommended for most orchards. 



A REPORT ON THE 1984 APPLE IPM PROGRAM 

W.M. Coli and R.J. Prokopy, Department of Entomology 
University of Massachusetts 

n.R. Cooley and W.J. Manning, Department of Plant Pathology 
University of Massachusetts 

and 

G. Morin and R.A. Spitko, New England Fruit Consultants, 

Lake Pleasant, MA 



Fiscal 198^ saw a continuation of the scaled down Apple IPM program, 
the focus of which is grower education and electronic information transfer. 
Grower interest in and support of IPM continued to be excellent. Private 
sector IPM scout/consultant service continued to expand in response to 
grower demand, evidence, we believe, of substantial grower commitment to an 
extension IPM approach. In addition, financial contributions to continua- 
tion of an apple IPM program and specialist position totalling $2,750 were 
received from 5 growers, representing about 18% of the state's tree fruit 
acreage. We wish to thank all contributing growers for their continued 
support of IPM educational efforts. 

Entomology and Plant Pathology Extension faculty and staff presented 4 
IPM training sessions in each of 3 regions, bringing growers up to date on 
new pest monitoring techniques and management strategies. These sessions 
allowed attendees to receive pesticide applicator recertification credits, 
and were well attended. Also, Ron Prokopy and Bill Coli presented two 
grower training sessions in the Hudson Valley of New York, also for recerti- 
fication credits. 

Program staff performed weekly scouting in 7 orchard blocks in Stowe, 
Sterling, Wilbraham and Ashfield. Additional orchard visits were performed 
to address specific insect/mite or disease problems on request. Numerous 
telephone inquiries relating to pest control were also received and 
addressed . 

During 1984, Susan Butkewich and Ron Prokopy evaluated fS newly labelled 
or experimental pesticides for effectiveness against a range of apple or 
pear insect and mite pests at the Hort. Research Center (HRC). They also 
studied time of tarnished plant bug (TPB) injury initiation and the most 
effective time of pesticide application against TPB. Further, they investi- 
gated plum curculio responses to odor of developing fruit and potential 
egglaying sites. Tom Green and Ron Prokopy analyzed apple blotch leafminer 
adult behavior in time and space in nature, while Martin Aluja and Ron 
Prokopy examined maggot fly responses to interacting synthetic fruit odor 
and visual trap stimuli. 



Acknowledgements : We wish to thank Ms. Kathleen Leahy for scouting and 
data-entry assistance, and Dave Lynch, Dana Clark, Jesse and Wayne Rice, 
Bill Broderick, Rich Smith, Elmer Fitzgerald Jr., Ed. Roberts Sr. and Tony 
Rossi for their cooperation. 



During 1984, Bill Manning and Dan Cooley monitored Venturia inaequalis 
(apple scab) inoculum levels, delivered infection potential information to 
growers via twice weekly pest alert messages, monitored orchards for new or 
unusual disease outbreaks (e.g., blossom end rots, a canker and dieback 
disease, and fungicide resistant V. inaequalis strains), and made control 
recommendations for specific disease problems on request. 

The V. inaequalis inoculum monitoring and pest message program involved 
several people from Bill Manning's laboratory and ran from April 1 to June 
15. In addition, adaptive studies of apple fungicide use were performed. 
Tests included an extended kick-back fungicide, a reduced rate of a standard 
fungicide (Captan) and a new, non-toxic polymer, all of which have the 
potential to reduce overall fungicide use in the state. 

Regional Fruit Speicialists Jim Williams and Karen Hauschild either 
performed weekly scouting or collected overwintered scab-infested leaves for 
laboratory assays of pathogen developmental state. Other information 
collected by private sector scout/consultants was also used to develop 
twice-weekly pest status messages, sent by computer from the University to 
regional specialists who then sent this information to growers in newsletter 
and 24 hour "code-a-phone" hotline formats. From early April through early 
bloom, utilization of the "code-a-phone" increased by about 20% over 1983. 
Unfortunately, technical problems caused failure of Jim Williams' machine 
between May 15 and 21, and again between June 11 and July 13. Periods of 
peak calling were associated with the end of primary scab season and times 
when spray decisions were being made for Plum curculio, Apple maggot fly and 
second generation Leafminer. 

A major goal was achieved with the publication of a 41 page manual 
entitled "Integrated Management of Apple Pests in Massachusetts and New 
England." This bulletin was funded in part by fruit grower contributions 
and by a grant from USDA. The manual contains nearly 100 color photographs 
for field identification of all major insect, mite and disease pests of New 
England. Also included are sections on Vertebrate pest management and 
Integrated ground cover management. Copies are available for $4.00 each 
from : 

Bulletin Center 

Cottage A 

University of Massachusetts 

Amherst, MA 01003 

Insect/Mite pest status and harvest injury, 1984 . Table 1 contains results 
oT private sector and extension IFM harvest surveys in 1984, and compares 
these to statewide averages of insect harvest injury in IPM blocks for 
1978-1983. Overall pest injury appears to be down in 1984 compared to the 
6-year averages, in spite of substantial rainfall during the early portion 
of the pest control season. 

Once again, the tarnished plant bug (TPB) caused the highest percent 
fruit injury detected in on-tree harvest surveys. However, 1984 TPB injury 
was about half of previous amounts. Most TPB injury we observed was one or 
two "dimples" in the fruit calyx, rather than more extensive "scabbing" seen 



on other occasions. These findings, combined with earlier work in Mass. and 
New York showing that only about 10% of on-tree TPB injury results in fruit 
downgrading, indicate that fruit culling or downgrading because of TPB 
injury should be of relatively little economic importance this year. 

Some possible reasons for the above include: improved monitoring of 
TPB activity, improved timing of TPB control sprays and/or substantial use 
of pre-bloom pyrethroid sprays (87% of monitored private sector IPM blocks) 
against TPB. Further, most TPB trap captures in Extension-monitored blocks 
were at or before tight cluster, when most TPB injury is expected to be in 
the form of aborted/abscised buds rather than fruit injury. 

European apple sawfly (EAS) injury was down somewhat, on average, com- 
pared to 6-year levels. This was in spite of the finding that many growers 
are delaying traditional petal fall insecticide sprays until plum curculio 
entry into commercial blocks. Some blocks experienced elevated EAS injury 
levels, perhaps because of pre-bloom insecticides, which normally provide a 
measure of EAS control, were less effective in this regard in 1984 due to 
excessive rainfall and early (about tight cluster) application of pre-bloom 
sprays. 

San Jose scale (SJS) injury was also down in 1984. Improved monitoring 
of problem blocks and increased use of chlorpyrifos (Lorsban*) for SJS 
control were factors in this observed drop in injury. Diazinon continues to 
provide excellent SJS control as well. Use of Penncap-M* against SJS was 
down this season; only 5 permits were issued for its purchase and use. We 
expect that these latter compounds will continue to have a role in SJS 
control programs, particularly with regard to second generation SJS, when 
Lorsban* use may not be possible (e.g. 28 day pre-harvest interval, and last 
2 uses in a season may not be closer than 21 days apart). 

Plum curculio (PC) injury was up in 1984, including both early-season 
injury and late season feeding injury as well. Frequent rainshowers during 
the period of PC migration into commercial blocks may have reduced insec- 
ticide residual protection, allowing higher PC injury, especially on block 
peripheries. Late season PC feeding was particularly evident where early 
season control was inadequate. Some growers experimenting with Lorsban* for 
PC control experienced a relatively high amount of injury, further con- 
firming earlier indications that this material should not be relied upon for 
PC control . 

However, Lorsban* was very effective against green fruitworm (GFW) 
populations, which earlier years' results indicated may be resistant to 
organophosphate insecticides. The resulting improved control probably 
accounts for marked decreased in GFW injury in problem blocks. 

Apple maggot fly (AMF) injury was low on average once again, perhaps 
due to improved monitoring and timing of control sprays. First AMF capture 
on red spheres was July 7 in an apparently early developing Ashfield block. 
Peak AMF captures, as in previous years, occurred in August, with substan- 

*Trade name ~~~ 



-tial activity detected into October in some blocks. Trap captures 
averaging more than 4 per trap were recorded in the above-mentioned Ashfield 
block at the end of September, with 13 AMF captured in one week, on a red 
sphere placed in a Golden Delicious tree. This offers further evidence of 
the importance of continued AMF monitoring, and control measures where 
appropriate, even after Mcintosh harvest has begun. 

Table 1. Percent insect-injured fruit in on-tree surveys of 38 commercial 
orchard blocks, 1984, compared to IPM orchard harvest injury 
averages, 1978-1979. 







19841 


1978-1983 


Insect Pest 




% injury 


% injury 


Tarnished plant bi 


'9 


0.95 


1.78 


European apple sa^^ 


/fly 


0.27 


0.40 


Plum curcul io 




0.56 


0.49 


San Jose scale 




0.32 


0.45 


Leafrol lers 




0.01 


0.03 


Green fruitworms 




0.02 


0.07 


Apple Maggot fly 




0.01 


0.07 


Other 







0.03 


Total injury 




2.14 


3,32 



^Combination of two sets of data. (1) Data from 31 blocks receiving private 
IPM scout/consultant services from New England Fruit consultants. Samples 
consisted of 50 fruits per tree on 6-20 trees per block. (2) Data from 7 
other commercial blocks collected by Extension IPM staff. Samples con- 
sisted of 100 fruits per tree on 4-10 trees per block. 

Mites continue to be a major pest problem for many fruit growers. 
Amblyseius fal lacis mite predators were again not an important biological 
control agent, having been detected too late in the season (mid-August) and 
in numbers too low to have major effect. No clear reason for this phenome- 
non is evident, although continued use of carbamate of pyrethroid insec- 
ticides, or "burnout" fungicides, harmful to A^ fal lacis may have been a 
factor in some blocks. However, A. fallacis numbers were also low in Hort. 
Research Center blocks which never received large scale use of such 
materials . 

Another interesting observation was the presence of early (late June) 
and severe two spotted mite (TSM) problems at several sites. Although no 
single factor can be pointed out which completely explains this occurrence, 
use of insecticides, fungicides and herbicides which are toxic to mite pre- 
dators may be one answer. 

Ironically, grower success in controlling European red mite (ERM) may 
offer another possible explanation. ERM overwinter as eggs on tree bark, 
while TSM overwinter as adults in groundcover and at the base of tree 
trunks. As a result, oil sprays may adequately control early ERM outbreaks 



-10- 

while having little or no effect on TSM. Further Dr. Rick Weires in New 
York has found that miticides differ to the extent that they provide control 
of the two mite species. For example, Kelthane*, in one test, had little 
effect on TSM while its effect or ERM is excellent in many cases. The net 
result may be that TSM are free to expand and fill an ecological niche 
vacated by the control of "resident" ERM populations. 

An interesting finding was the presence of numerous TSM in the carmine 
(bright red-orange) phase in the calyx of Red Delicious apples at the HRC. 
The observed mites were found during the course of a harvest survey, and 
were all adults (TSM overwinter as adults) and were associated with substan- 
tial silken webbing. TSM in the carmine phase have been commonly observed 
in Ontario and New York in the past, but this is our first observation of 
such colored forms in Massachusetts. Positive identification of this insect 
was confirmed by personnel at Beltsville, Maryland to eliminate the possi- 
bility that these mites were the McDaniel spider mite, a pest of tree fruits 
on the West Coast but not known to exist in the Northeast. 

Whatever the cause of observed TSM outbreaks, mite control is clearly 
not getting any easier, particularly when one considers apparent (and docu- 
mented in certain areas) resistance of ERM to certain miticides. Ors. 
Reissig and Weires in New York report preliminary suggestions that some 
insecticide/mite interaction exist, whereby spraying of certain pesticides 
may actually enhance mite population increases directly (not indirectly, as 
by killing predators ) . 

Experience in 1984 reinforces our belief that multiple application of 
low rates of miticide early in the season (PF-2nd cover) in problem blocks, 
particularly when combined with thorough oiling, may provide excellent, 
season-long mite control. 

Leafminers (LM) were only occasionally a problem in Massachusetts, with 
most growers achieving excellent LM control using endosulfan, oxamyl , metho- 
myl or pyrethroid insecticides. In one instance, for example, methomyl 
applied to ?nd generation LM sap-feeding mines (<10% of mines in tissue 
feeding stages) above our provisional ETL resulted in greater than 94% kill, 
and completely arrested that generation. 

Red visual traps for LM monitoring were again useful. Trap captures 
of overwintering generation LM indicated no need to treat for LM in 5 of 6 
monitored blocks. In 3 cases, grower use of pyrethroids in the remaining 
orchard blocks was unnecessary. Growers are urged to rely on LM monitoring 
to determine the need for treatment so as to avoid unnecessary use of 
phyrethroids. 

Outbreaks of other pests such as white apple leafhopper and wooly apple 
aphid were noted at a few scattered sites. A noteworthy observation was 
detection of noticeable amounts of fruit injury at the H.R.C., caused by 
Eye-spotted budmoth (ESB), Injury from ESB normally consists of 2-3 
"stings" resembling those caused by small codling moth larvae and typically 
hidden under a leaf webbed with silken threads to the side of fruit. (ESB 
is in the same entomological "family" as codling moth - the Olethreutidae. 
However, ESB larvae are quite distinct in appearance, with a shiny dark 
brown head and thoracic shield with a dull, reddish-brown body). 



-11- 

Disease Injury . In general, apple scab pressure was extremely high this 
year. Growers who used regular contact fungicide applications, with limited 
combinations of either Cyprex or Benlate had good control if they maintained 
good coverage going into infection periods. Funginex plus a contact fungi- 
cide applied 3 days or less after an infection period also worked very well. 
Most growers applied from 7 to 10 fungicide sprays during primary scab 
season, which lasted from April to June 10 (exact dates depended on the 
location). Fortunately, during the prolonged rain around May 30, most areas 
were past the period of maximum ascospore pressure. However, extensive scab 
was evident in many commercial blocks, requiring repeated eradicant sprays 
to prevent spread of secondary inoculum to fruit. 

Blossom end rot incidence was higher than normal. The two organisms 
associated with this year's outbreak were Sclerotinia and Botrytis , two com- 
mon end-rot fungi. As usual, most infected apples had dropped by 
mid-August . 

This year, the first case of benomyl -resistant scab was confirmed in 
Massachusetts. The grower who developed the problem had been involved in 
testing the compound early in its development. He has used benomyl alone, 
and benomyl combinations for over ten years. 

Plans for 1985 . It appears that funding for Extension programming in 
Apple IPM wil 1 be down somewhat from 1984 levels. Inspite of this, we plan 
to expand Extension's monitoring program to include blocks in the Granville 
area, presently not being scouted by Extension or private sector scouts 
(other than some grower scouting). 

As in 1984, the purpose of this and other scouting in 1985 will be to 
develop the twice weekly pest status messages, rather than provide a 
scouting and grower advice service as had been the case during the pilot 
program phase. 

Growers interested in obtaining sector IPM scouting/consulting services 
are encouraged to contact the individuals listed below. 

Boston IPM, Inc. 

242 Cayenne St. 

W. Springfield, MA 01089 

413-736-8404 

New England Fruit Consultants 

P.O. Box J. 

Lake Pleasant, MA 01347 

413-367-9678 

As in 1984, Extension faculty and staff will continue to provide IPM 
training to update growers on insect/disease biology and in latest develop- 
ments in monitoring techniques, action thresholds, and appropriate control 
strategies. 



-12- 



In addition, orchard visits will be performed as needed or by request 
to address specific problem areas. Growers who feel they have experienced 
control failures due to suspected pesticide resistance (re: Mites, fruit- 
worms, apple scab, leafhoppers, etc.) in 1984, are encouraged to contact 
appropriate extension workers in advance of the 1985 season. 

Finally, we continue to welcome grower contributions large or small, to 
a continued Extension IPM effort. Such contributions will enable us to pro- 
vide an ongoing IPM educational effort, despite reduced Federal funding for 
Apple IPM. 

POMOLOGICAL PARAGRAPH 

William J. Lord 
Department of Plant and Soil Sciences 

Spur-type Trees Can Reduce Pruning Time by 60% . Pruning apple trees is very 
time consuming and may be the second largest cash cost for producing the 
crop of apples. It is known that spur-type trees require less pruning than 
non-spur trees of the same cultivar and age. However, we were interested in 
actually recording the difference in time required to prune mature non-spur 
and spur Delicious trees at the Horticultural Research Center (HRC) in 
Belchertown, MA. 

Table 1. Time required to prune non-spur and spur-Delicious trees in 1980 
and 1981.* 



Delicious 


Growth 


Time 


size 


■ (ft.) 


Time/tree to 


prune(min.) 


strain** 


habit 


Ht. 




Spread 


1980 


1981 


Gardiner 


Non-spur 


13.3 




18.8 


13.8 


19.5 


Richared 


Non-spur 


12.5 




18.5 


13.7 


17.8 


Bisbee 


Spur 


11.6 




13.3 


3.8 


5.2 


Sturdeespur 


Spur 


12.0 




13.8 


4.8 


8.2 



*Trees pruned by Richard Clark of the HRC. 

**Trees planted in 1964. 

In Table 1 it is obvious that the spur-type trees were much smaller 
than the non-spur trees. This fact plus the presence of fewer lateral 
branches and watersprouts on the spur-type trees reduced the overall pruning 
time for the 2 years by 60% on these type trees in comparison to the non- 
spur trees. Thus, it appears that the reduction in pruning time on spur 
trees should more than compensate for higher tree numbers/acre in plantings 
of spur trees in comparison to non-spur trees. 



-13- 

REDUCING WINTER INJURY TO TREE FRUITS 

W. J. Lord, Department of Plant and Soil Sciences 

Pomologists in the early 1900 's considered winter injury to roots to be 
a major problem of tree fruit production in northern growing areas. 
Nevertheless, root-kill of fruit trees apparently has occurred only twice in 
Massachusetts during this century. Reportedly, it occurred during the 
severe winter of 1903-04 and it did occur in the "open-winter" of 1978-79. 
Much more frequent in Massachusetts is injury to apple tree trunks asso- 
ciated with winter freezes or early-winter pruning. 

Two types of damage occur to trunks of fruit trees. The first occurs 
in midwinter at the time the low temperature is encountered. The tissue in 
the trunk contracts unequally and the trunk simply cracks open (Southwest 
injury). The second type is actual death of the cambium layer in the trunk. 
In the spring xylem layer swells but the cambium has not laid down new cells 
for expansion. The bark splits away from the trunk as a result. The latter 
type of damage, which is generally associated with early pruning, causes 
more trouble since it involves actual death of tissue. 

Southwest injury on both apple and peach trees can be reduced by appli- 
cation of white latex paint to the southwest side of the tree trunks 
including the base of the lower scaffold limbs. Use only latex water 
soluble paint. Do not use oil or lead-base paints soluble in paint thinner 
or turpentine because they can injure trees. Whitewash, a mixture of lime 
and water, can be substituted for white latex paint, but durability is poor 
and it may not last through the winter. 

A delay in vegetative maturity (the physiological stage where deciduous 
fruit trees cannot be forced to resume growth if defoliated) will delay 
acclimation to low winter temperatures. Factors which delay or prevent 
tissue maturity and cold acclimation include high nitrogen nutrition, late 
cultivation and irrigation, early defoliation, heavy cropping, not picking 
fruit on trees, and early pruning (before Christmas). 

Rate of decline in temperature during the Fall can affect cold 
resistance even though the same minimum temperature is obtained. A slow 
decrease allows acclimation to occur, whereas a rapid decrease reaches a 
level too low too quickly for acclimation to occur. Optimum temperatures 
for acclimation are 25° to 30° F. Keep a record of minimum and maximum tem- 
peratures, beginning November 1. Delay pruning until February if there have 
not been 25 days with minima of 28° F or lower by December 25. Do not prune 
within 10 days following maxima of 55° F or more that occur before 
Christmas. 

Pruning immediately prior to a freeze greatly increases injury to the 
tree. The fresh cut apparently stimulates cellular activity and/or creates 
a strong sink (attraction) for growth hormones, both of which deharden the 
tissue. Therefore, listen to weather forecasts and stop pruning if a severe 
cold front is on its way. Prune old apple trees first and do not prune 
young trees before late February. 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. 



.14- 



VARIABLES INFLUENCING SIZE OF APPLE TREES, AND SUGGESTED TREE SPACINGS 

William J. Lord, Department of Plant and Soil Sciences 

Apple trees on size-controlling rootstocks (compact trees) can produce 
more bushels of U.S. Extra Fancy grade fruit per acre and reach maximum pro- 
duction at an earlier age than larger trees because of better exposure of 
foliage and fruit to light and bearing surface and more bearing surface per 
acre. Unfortunately, the increase in productive leaf surface and/or early 
yields frequently are not as great as would be expected because of influen- 
ces of soil and management (includes supporting leaders) on tree size and 
tree spacing. 

In this article we list some of the variables that influence tree size 
and give examples of the effects of these variables based on measurments at 
the Horticulture Research Center and grower orchards, and observations in 
pruning trials (Table 1). These illustrations show why it is extremely dif- 
ficult to select the correct tree spacing. 

We have learned that, under our conditions, very close tree spacings 
generally are not satisfactory in Massachusetts because of tree crowding 
problems. In contrast, trees in many plantings on M26 have failed to fill 
their allotted space, and leaf surface per acre is further reduced because 
of the failure to support the leaders. The writer recognizes that it is not 
possible to select perfect tree spacings because of the variables influenc- 
ing tree size. Nevertheless, the guide in Table 2 may prove useful since it 
represents our experience over many years. 

We have allotted an 8 foot alley for orchard travel, with some excep- 
tions for trees on M9 rootstock. Reducing the between-row spacing by 2 feet 
will increase tree number considerably but unless smaller equipment is 
available a 6 foot alley may be too restrictive for orchard operations. 

"Mark", a recently released rootstock will create considerable commer- 
cial interest. Our very limited data indicate that Mark may produce a tree 
slightly larger than M26. For trees on Mark we tentatively suggest allowing 
2 feet more spacing in the row and between rows than suggested for trees in 
Table 2 on M26, M9/111 or M^/infi. 



-15- 

Table 1. Variables influencing apple tree size and tree spacings and examples of 
the effects of these variables. 

Variable or Variables Example of effect of variable 

Soil 1. In an experiment with young Mcintosh trees on 10 dif- 

ferent soils, tree size differs as much as 50% among 
sites. 

Rootstock 1. Mcintosh on M7A may be 55-75% as large as when on a 

seedling tree. 

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GREEN FRUITWORM RESISTANCE TO GUTHION IN WESTERN MASSACHUSETTS! 

Glenn E. Morin and Roberta A. Spitko 
New England Fruit Consultants 
Lake Pleasant, Massachusetts 

In recent years, commercial apple growers in the Shelburne area of 
western Massachusetts have experienced problems controlling (jreen fruitworm 
larvae (GFW] with the standard insecticide Guthion* (azinphosmethyl ) . GFW 
injury to fruit at harvest increased from a previously insignificant n.01% 
in 1981 to greater than 4% in 1983 in one Shelburne orchard despite the tra- 
ditional application of post-bloom Guthion* treatments. 

Were we witnessing the development of green fruitworm tolerance to 
Guthion* or merely the cyclical appearance of a pest not well controlled by 
this material? We have provided below a brief life history of GFW common to 
Massachusetts, have described our attempts to identify this control problem 
in one commercial orchard, and have included alternate strategies for 
managing potentially resistant populations. 

Life History 

Green fruitworm adults appear in orchards and begin egglaying in late 
March or earl/ April. Upon hatching, young larvae attack foliage and buds. 
Larvae may va 'y from light to dark green with green head capsules and a pair 
or pairs of lateral white stripes. Mature larvae chew holes in developing 
fruits and may cause substantial injury. Larvae burrow into the soil in 
late June and emerge as adults by the following April. Severely damaged 
fruits abscise during the growing season. Minor damage generally appears on 
fruit at harvest as large, superficial areas of light corky tissue but may be 
so extensive as to expose the seed cavity. 

Field Observa t ions 

Increased GFW-like injury was first brought to our attention during the 
1982 harvest season. Unfortunately, GFW damage is virtually indistinguish- 
able from that of the oblique-banded leafroller without observations of lar- 
vae at the time of initial injury. Careful monitoring the following season 
was necessary to positively identify the culprit. 

In 1983, we initiated a foliar monitoring program at pink when chewing 
injury to terninal growth was first noted. Terminal damage increased to 
more than 30% by late bloom and limited injury to fruit clusters had begun. 
Insecticide treatments were warranted to prevent excessive fruit injury and 
full rate Guthion* applications were made at petal fall, first cover, and 
second cover at 7-day intervals. These treatments were apparently unsatis- 
factory as fruit cluster damage continued to increase and live GFW larvae 
(tentatively identified as Orthosia hibisci "Guenee") were detected after 
each application. Injury to fruit at harvest was greater than 4%. 

^We would like to express our appreciation to the Peck families of Valley 
View Orchards in Shelburne, Massachusetts for their extreme level of 
interest and cooperation in this investigation. 

*Trade name 



- 7 - 

Due to these observations, insecticide tolerance was strongly 
suspected. Post-bloom Gutbion* treatments had proved effective in the past 
as GFW injury was rarely noted in the packhouse. In addition, GFW damage 
had not increased in other major fruit growing regions of the state despite 
the use of similar spray schedules. Guthion* was apparently still effective 
in these areas where GFl! injury averaged less than 0.1% in 1^83. 

Tolerance Study 

To investigate the possibility of insecticide resistance, we collected 
GFVI larvae from the Shelburne population during bloom of 1984, caged them on 
abandoned apple trees, and subjected them to various rates of Guthion*. 
Treatments were made at petal fall when commercial insecticides would likely 
be applied. A Lorsban* (chlorpyrifos) treatment was included for evaluation 
as an alternate material should Guthion* prove ineffective. Our results are 
presented in Table 1. 

Table 1. Results of several organophosphate insecticide treatments against 
GFV/ larvae (tentatively identified as Orthosia hibisci 'Guenee') 



Material and formulation Lbs/100 gal % Mortality 



Guthion SOUP 0.5 30 

Guthion 50WP 1.0 30 

Guthion 50WP 2.0 55 

Lorsban 50WP 1.0 95 

Control 5 



The data clearly indicate that neither the full label rate nor the 
double rate Guthion* treatments proved effective against these larvae, 
resulting in only 30% mortality. If relied upon for control, these treat- 
ments would have allowed the survival of a residual population capable of 
subs' antial fruit injury. Even the quadruple rate resulted in only 55% kill 
and we repeatedly observed larvae continuing to feed on fruit and foliage 
desp te the visible presence of a heavy spray residue. Lorsban* proved a 
highly effective material that resulted in 95% mortality. 

Summa ry 

Baseri on the work presented here, we believe that insecticide tolerance 
to Guthicn* (azinphosmethyl ) was involved in the GFW control failures 
recently experienced by fruit growers in western Massachusetts. We recom- 
mend careful monitoring of GFW larval populations on an orchard-by-orchard 
basis and the use of alternate post-bloom insecticides should damage exceed 
acceptable levels. 



- 8 



Our tolerance study indicated that Lorsban* (chlorpyrifos) would be a 
viable substitute and our field trials in 1984 support these results. A 
single petal fall application on the same acreage as previously discussed 
provided excellent control of GFW larvae resulting in less than 0.4% injury 
to ■''ruit at harvest. Thiodan* (endosulfan) also proved to be an effective 
material in a similar trial and due to its relatively mild effect on benefi- 
cial mite predators, it would be well suited to an integrated mite control 
program. 

Pesticide resistance and subsequent control failures are common pheno- 
mena. Occurrences such as the one described here continue to remind us of 
the need for pest monitoring programs and the selective use of pesticides in 
order to lengthen the effective "lifetime" of current spray materials. 

***** 



SOME COMMENTS ON APPLE TREE NUTRITION 

William J. Lord 
Department of Plant and Soil Sciences 



James T. Williams, Massachusetts Regional Fruit Specialist, reports the 
'"oHowing summary of apple leaf analyses for Northeastern Massachusetts 
jrchards in 1982 and 1«83. 



Pet. of samples Pet. of samples 

Element below optimum range above optimum range 



Nitrogen 8 15 

Potassium 31 6 

Calcium 50 

Magnesium 5 1 

Boron 17 

Manganese 10 10 

Copper 36 3 

Zinc 5 40 



A grower should obtain leaf analyses to assess the status of his own 
orchard, hut the table above shows that calcium, copper, potassium, and 
boron were most frequently deficient in leaves, and that zinc and nitrogen 
were the elements most commonly in excess. 

Some general comments about apple nutrition follow. 

Apple tree nutrition . The needs of apple trees for mineral elements are 
smaller than those of many other crops. Nevertheless, the problems of main- 
taining optimum nutrition are complex because of the concern with nutrition 
of both the tree and the fruit, and because of the influence of soil manage- 
ment and orchard intensification on mineral availability. 



Much less N is being applied in orchards than in the past because of the 
reduction or elimination of grass and weed competition by the use of her- 
bicides. Furthermore, apple trees conserve N by translocating part of the 
nitrogenous material in senescing (aging) flowers and leaves to adjacent 
bark and wood tissue. The N becomes part of the protein fraction. The pro- 
tein levels in shoot bark and wood decrease rapidly before bud-break in the 
spring. This decrease is accompanied by increased levels of soluble N. 
Thus, this N is available to help support growth in early spring when con- 
ditions for root uptake are poor. 

Potassium (K) is the most abundant nutrient in the fruit. Therefore, 
the level of cropping greatly influences the demand for K. In contrast, 
very small amounts of calcium (Ca) are found in the fruit and this repre- 
sents a small proportion of the total uptake of this element, emphasizing 
that one of the problems of Ca nutrition is that of distribution in the 
tree. Fruit are often Ca-deficient when leaves have sufficient Ca. The 
effects are described in a following article (pages 14 and 15). 

Manganese (Mn) . In the spring, 1984 issue of Fruit Notes , it was stated 
that Mn is the most frequently deficient elemerTE in apple trees. This 
statement was in error! Low Mn is the most frequent foliar symptom of defi- 
ciency seen in Massachusetts. However, foliar symptoms of Magnesium 
deficiency have become increasingly prevalent the last 3 or 4 years. 

A standard for apple tree growth . Vihile the amount of growth made by a tree 
"Ts dependent on several factors, some of which cannot be controlled by the 
grower, it is desirable to set up standards to strive for. The stronger 
shoots of young bearing trees 5 to 10 years of age should make 15 to 20 
inches of growth each season. Older trees should have many shoots which 
make 8 to 10 inches of growth. Thickness of shoot growth is <'ully as impor- 
tant as length. Stocky shoots are the sign of a vigorous tree while slender 
shoots indicate a poor, under-nourished tree. 



***** 



POMOLOGICAL NOTES 

V/illiam J. Lord 



Plant trees early . Tree roots will grow when the soil temperature reaches 
about 45oF. Thus, early planting allows the roots to become established and 
to make growth before high air temperatures cause rapid growth above ground. 

CHEMICAL THINNING OF EMPIRE . It is well known that trees of this variety 
tend to produce only medium-size fruit. For example, fruit on young trees 
in experimental plots in 1982 and 1983 averaged only 2 1/2 inche"s Tn 
diameter partly because of excessive fruit set. Thus, questions have arisen 
concerning chemical thinning of Empire. Based on a thinning trial in 1982 
and 1983 by Dr. Duane Greene, we tentatively suggest an application of NAA 
pi'js 1 lb. of sevin, 50% V/P or its equivalent. 



10 



SUGGESTIONS FOR FERTILIZATION OF PEACH TREES 



William J. Lord 
Department of Plant and Soil 



Sciences 



Tree growth is the best guide to how your fertilizer program fulfills 
the needs of peach trees, if soil moisture is not a limiting factor. Since 
flower buds of the peach are formed along the new shoot growth, it is essen- 
tial to produce adeguate growth by use of a nitrogen (N) fertilizer. Young 
peach trees should make about 18 inches of new terminal growth annually; 
12-15 inches are sufficient for mature trees. Growth in excess of these 
amounts may result in poor fruit color and excessive cold injury, and will 
increase the amount of pruning required. 

In some orchards, N is the only fertilizer required. However, leaf 
analysis in conjunction with visual observations of tree growth and fruit 
quality are the best criteria by which to determine required amounts of fer- 
tilizers (Table 1). In Massachusetts, N needs are usually met with an 
application of ammonium nitrate or a "complete fertilizer." Foliar sprays 
of urea to supply N are ineffective on peach trees because the leaves do not 
absorb N as efficiently as do apple leaves. 

Table 1. Standards for nutrient levels in peach leaves. 



Element 

Nitrogen 

Potassium 

Calcium 

Magnesium 

Boron 

Copper 

Manganese 

Zinc 



Shortage^ 
fless than1 



3.00% 

1 . 25% 

1 . 35% 

0.25% 

25 ppm 

5 ppm 

25 ppm 

15 ppm 



Optimum^ 


Excess^ 


(within) 


(more than) 


3.00 - 3.50% 


3.70% 


1.50 - 2.50% 


2.50% 


1.35 - 1.50% 


? 


0.35 - 0.50% 


0.50% 


30 - 50 ppm 


60 ppm 


7-10 ppm 


10 ppm 


90 - 110 ppm 


110 ppm 


25 - 50 ppm 


50 ppm 



^Shortage: Corrective measures needed. 

^Optimum: Applications should be continued at present rate or adjusted 
according to anticipated crop size. 

•^Excess: Amount applied should be decreased or eliminated. 



- 11 - 

Some growers apply split applications of N, the first in mid-April to 
early- May and the second in June, The amount applied in June is 1/3 to 1/2 
of the amount applied earlier. We have no data regarding the benefit of 
split applications. However, at our Horticultural Research Center, we apply 
only one application and are satisfied with tree growth and yields. 
Probably a good soil management program which conserves soil moisture, or 
the installation of a trickle irrigation system, would be more beneficial 
than a second application of N. 

Potassium (K) is occasionally deficient in Massachusetts peach 
orchards. Therefore, the recommendations given in Table 2 are guides for 
fulfilling the N and K needs for peach trees. The K may be applied either 
in the spring or fall, but N fertilizer should be applied in the spring 
about 2 or 3 weeks before bloom. 

Table 2. Suggested rates of fertilizer for bearing peach trees. 



Approxima te amounts per tree (1bs) 
Tree age (years) Ammonium nitrate Muriate of potash 

or its equivalent or its equivalent 



3 to 6 1/2 to 1 1 to 2 

6 to ^ 1 to 1 1/2 2 to 3 

9 to 12 .1 1/2 to 2 3 to 4 

12 and over 2 to 4 4 to 8 



Research by Drs. Dennis Abdalla and Norman Childers in 1970-72 at 
Rutgers University, New Brunswick, New Jersey, showed that we should be more 
concerned about calcium (Ca) nutrition of our peach trees. Fruit from trees 
g-'own under greenhouse sand culture by these researchers were smaller, 
greene'' and firmer and had less soluble solids (sugar content) and red blush 
when the nutrient solution was low in Ca. Our apple trees and fruit in 
Massachusetts are low in Ca, thus the same may be true for peaches. The 
question is, how can you increase the Ca level in peach trees and fruit? 
Our suggestion is to use high Ca lime when liming the orchard. 

Manganese (Mn) deficiency occurs occasionally in Massachusetts peach 
orchards. T'-ees with Mn deficiency have leaves with interveinal fading of 
chlorophyll with the remaining area green. Leaves from peach trees showing 
Mn deficiency in 1971 contained 13 ppm of this element in comparison to 97 
ppm in leaves from trees showing no interveinal loss of chlorophyll. 

Mn deficiency can be corrected by foliar applications of manganese 
sulfate or by use of a fungicide containing Mn. If using manganese sulfate, 
apply about first cover at a rate of 3 lbs per 100 gallons of water. When 
using a Mn-containing fungicide apply 2 or 3 applications with timings about 
petalfall and first and second covers. 



- 12 



Occasionally, leaf analysis indicates that trees are low or deficient 
in magnesium (Mg) (Table 1). The first indication of deficiency is a light 
yellowing between veins of the leaf. When Mg deficiency is severe, browning 
of the yellowed areas occurs. Usually, the more basal leaves are affected 
first. For long-term correction of low or deficient Mg levels, apply dolo- 
mitic limestone at the rate indicated by a soil test. For a more immediate 
correction of Mg deficiency, a foliar spray of magnesium sulfate (Epsom 
salts) is suggested in some peach growing ar.^as. The suggested rate is 10 
pounds of Epsom salts per 100 gallons of water. 

Peach trees sre more sensitive to excessive applications of B than 
apple trees, thus this element should be applied only in small amounts if 
needed. Peach tree symptoms of excessive B are characterized by withering 
and dying-back of terminal shoots during the growing season, the development 
of cankers and gumming along the shoots, rough bark, prominent lenticels, 
and excessive development of lateral shoots. To avoid B toxicity, Ernest G. 
Christ, former Extension Specialist of Pomology at Rutgers University, is 
very cautious about recommending the use of this element when fertilizing 
peach trees. He states that. . . "fertilizer with 5 pounds of borax per ton 
is usually OK for peaches. No additional B is ever needed or added. Also, 
keep pH of soil 6 - 6.5." We suggest that peach growers in Massachusetts 
follow the recommendations of Ernest Christ concerning use of B. 

***** 



UNDERSTANDING EFFECTS OF WEATHER ON APPLE YIELDS 

Wil 1 iam J. Bramlage 
Department of Plant and Soil Sciences 

Year-to-year variations in fruit yield from an orchard are usually 
accepted as a fact of life, but what are their underlying causes? J.E. 
•Jackson and P.J.C. Hamer of the East Mailing Research Station, Kent, England 
compared estimated yields of English 'Cox's Orange Pippin' apples with 
weather records from 1949 to 1975 and came up with some interesting results 
( Journal of Horticultural Science s 55 : 1 49 - 1 56 ) . 

Over this time there was a steady increase in yield amounting to about 
0.25 ton per hectare (about 7 bushels per acre). This steady increase was 
attributed to technological changes in production practices, in particular 
the use of better rootstocks and closer spacing of trees. This "technologi- 
cal advancement" would amount to an extra yield of 180 bushels of apples per 
acre in 1975 above the average yield in 1949. 

In addition to this steady increase in yield, 3 weather factors were 
closely related to year-to-year variations. They were: (a) relatively high 
temperature in February, March, and April; (b) relatively high temperature 
immediately after full bloom (typically mid-Hay); and (c) relatively cold 
weather in June. 



- 13 



Warm weather in February, March, and April produced an earlier bloom 
and lowered yield. This was not due to a greater frequency of frost damage, 
as wlrm periods tended to continue on into summer. The authors suggested 
that the early bloom produced by this weather either resulted in "poorer 
quality of flowers" or else was associated with lessened insect activity. 
In either case, poorer fruit set would result. Relatively high tempera- 
tures immediately after full bloom increased yield. The authors related 
this to known effects of temperatures on pollen tube growth, suggesting that 
rapid pollen tube growth increased fertilization of seeds and produced 
higher yields (fruit size tends to increase with seed number). Relatively 
cool weather in June related to reduc ed yields. The authors suggested that 
this was due to slower growth during This time of cell division and/or to 
poorer fruit retention during June drop. 

Together, these 4 factors (technological improvement and temperatures 
during these 3 key times) accounted for 80% of the variation in estimated 
yield over this time period. Using this information, "expected yield" was 
calculated for each of these years and the values were very close to actual 
estimated yields in all years except those in which some frost damage 
occurred. Thus, it appears that the ideal weather for high yields in 
England would be to have (a) a relatively late Spring, (b) relatively high 
temperatures immediately after full bloom, and (c) relatively high tempera- 
tures again during late June. 

Dr. Alan Lakso of the New York Agricultural Experiment Station, Geneva, 
NY, has examined the effects of temperature from February 1 to April 15 on 
New York apple yields over a 15-year period ( The Great Lakes Fruit Grower s 
News , April, 1984). He found results similar to those of Jackson and Hamer 
in England . 

Using the mean maximum temperature for February 1 to April 15, he found 
that higher temperatures lowered yield. The relationship of weather to 
yield was further improved by considering the mean temperature during the 
two weeks after petal fall, in which higher temperatures increased yield. 
Using just the temperatures for these two periods of the year, 80% of the 
annual variation in apple yield was accounted for. 

Information such as this may allow early predictions of yields and aid 
growers in making management decisions about their crops. 

***** 



POMOLOGICAL PARAGRAPH 

Rootstock mixtures . In Massachusetts Agricultural Experiment Station 
Bullftin No. 418 published in 1944, J.K. Shaw stated "we are inclined to 
favor Ml, M2, M4 and M7 as the semi-dwarfing rootstocks most likely to prove 
valuable and it wou 1 d simpl ify matters if this list could be shortened ." In 
the 1930s and 1940s, the Mailing series were the only available rootstocks. 
Certainly, the chance of mixtures is much greater today because of the 
numerous rootstock introductions since the 1940s. 



14 



RECOMMENDATIONS FOR USE OF CALCIUM SPRAYS 

William J. Bramlage and Mack Drake 
Department of Plant and Soil Sciences 

Our surveys of Massachusetts orchards have shown that concentrations of 
calcium (Ca) in apple fruits are more variable than those of any other 
mineral, and that fruit from many orchards are Ca def icient--which makes 
them more susceptible to breakdown, bitter pit, scald, and rot during and 
after storage. To combat this problem, most Massachusetts apple growers 
have been foliar spraying calcium chloride (CaCl?) periodically during the 
growing season. Our current recommendations for use of Ca sprays in apple 
orchards are described here. 

Many Ca-containing compounds have been tested for use on apples and a 
number of different ones are commercially available. Technical grade 
(77-80%) CaCl2 is the material we recommend. We have tested a number of 
different materials and found that the amount of Ca that they put into 
apples is directly proportional to the concentrations of soluble Ca in the 
spray solution. With the exception of the relatively insoluble material, 
Ca{H2P04)2, which was ineffective in increasing fruit Ca, neither the for- 
mulations of the material nor the chemical that is associated with Ca in the 
material has significantly affected the final result. Technical grade CaCl2 
is the most economical material for adding the needed Ca to apples. 

Foliar CaCl2 sprays should begin about 3 weeks after petal-fall and be 
repeated at 2-week intervals, totaling about 8 applications for the season. 
The CaCl2 can be combined with pesticide sprays. Since young leaves tend to 
be sensitive to CaCl2, we recommend using 6 lbs per acre in each spray until 
mid-July, and then 8-10 lbs per acre until harvest. The goal should be to 
apply a total of 70 to 75 lbs of CaCl2 per acre for the season. While we 
recommend the above rates, we have fouhd that minor alterations of these 
rates and timings have been just as effective in raising fruit Ca levels as 
the recommendations so long as the same total amount of CaCl2 is applied. 
In other words, if lower rates are used'j more sprays are needed. When 
higher rates are used the risk of damage from Ca sprays is increased. 

Ca sprays can cause damage to leaves or even fruit. With CaCl2, leaves 
are much more likely to be damaged than fruit, the injury normally appearing 
as browning of the leaf margins. We have sought a less phytotoxic form of 
Ca but have found no material that was safer than CaCl2 when applied at an 
equal soluble-Ca concentration. Tests in other areas have shown that 
calcium nitrate (Ca(N03)2) is less damaging to leaves than CaCl2, but is 
more likely to cause fruit injury (black spots on the lenticels). We recom- 
mend the use of CaCl2 rather than Ca(N03)2 to minimize the risk of fruit 
damage. While leaf injury is undesirable, we have observed no detrimental 
effect to either fruit or trees when mild symptoms have developed. However, 
severe damage could cause earlier fruit ripening and dropping. 



- 15 - 

Some growers have chosen to use Ca(N03)2 to reduce the risk of leaf 
injury. We have applied Ca(N03)2 in concentrations of soluble Ca equal to 
those of the recommended rates of CaCl2, and have found that equal amounts 
of Ca are added to the fruit. However, the overall effects of the treat- 
ments on fruit and trees have not yet been determined, and we believe that 
CaCl2 is the material of choice. 

To minimize risk of foliar damage from CaCl^ sprays, care must be 
taken. Sprayers need to be calibrated. CaCl2 should always be mixed in a 
pail of water and be added last, when the spray tank is nearly full, to 
ensure thorough mixing in the tank. The spray tank must have sufficient 
agitation to maintain thorough mixing during spraying. Risk of damage is 
greatest on weak trees or injured foliage. We are aware of no known incom- 
patibility of CaCl2 with commonly used pesticides, but since formulations 
and combinations frequently change, users should be alert to any unusual 
behavior of materials in the spray mixtures. Do^ not mix CaCl2 with Solubor 
or Epsom salt sprays . Do not apply CaCl2 in excessively hot weather. 

Foliar CaCl2 sprays may be applied as either dilute (300 gal per acre) 
or lOX concentration (30 gal per acre). We have seen indications that 
uptake of Ca by apples can be greater from concentrated than dilute sprays, 
but other researchers have found that these methods of CaCl2 application add 
equal amounts of Ca to apples. Some growers have applied CaCl2 at higher 
than lOX without problems, but we have no data on their effectiveness. If 
CaCl2 is applied in a dilute form and separate from pesticides, a non-ionic 
wetting agent should be added, but since most pesticides include wetting 
agents in their formulation the addition should not be needed when CaCl2 and 
pesticides are combined. 

The initial pH of commercial CaCl2 in water is about 10.3, since small 
amounts of free calcium oxide form calcium hydroxide in water. There is 
evidence that this high pH may reduce effectiveness of some pesticides. We 
therefore, have recommended adding 2 quarts of 5% vinegar per 100 pounds of 
CaCl2 to neutralize the alkalinity and bring the spray solution to about pH 
6.0. The addition of vinegar will not affect uptake of Ca by the apples, or 
injury to the foliage. (Please see the following articles for more infor- 
mation about this pH problem.) 

Use of CaCl2 as a foliar spray for apple trees is an established annual 
practive in mo' t Massachusetts apple orchards. While this material can be 
phytotoxic, thf risk of injury is minimized by attention to details when it 
is used. The !)enefits from its use are substantial. When 70 to 75 lbs per 
acre are applied, potential storage life of the fruit can be greatly 
improved. However, many growers apply less than 70 lbs per acre, and poten- 
tial benefit declines proportionally as less than this total is applied 
during the growing season. Our recommendations are designed to obtain the 
greatest benefit from CaCl2 most efficiently, while minimizing the risk of 
foliar damage. Since there is no carryover of this Ca benefit, it is 
necessary to apply the sprays at full dosage each year for maximum benefit. 



- 16 



APPLE COVER SPRAYS UNAFFECTED BY THE ADDITION OF CALCIUM CHLORIDE* 

George M. Greene, Larry A. Hull, and Kenneth D. Hickey 
Pennsylvania State University 



From a fruit quality standpoint, it has been proven that calcium 
chloride (CaCl2) can reduce corking and bitter pit and can lengthen the 
storage life of apples. Research conducted under the CIPM apple subproject 
hi 
di 
eqi 

cides arid CaCl2 can be safely combined, eliminating the necessity for 
making s?parate applications. 



storage life of apples. Research conducted under the CIPM apple subproject 
las proven that the addition of CaCl2 to pesticides sprays normally used 
iuring the post-bloom period results in disease, insect, and mite control 
?qual to that obtained when the pesticides are applied alone. Thus, pesti- 



Apple growers the world over are plagued by low calcium physiological 
disorders of fruit. These disorders can appear during the growing season or 
they may develop during the postharvest storage period. CaCl2 can often 
effectively reduce the level of these disorders. Therefore, recommendations 
have been developed to apply various rates of CaCl2 depending on the apple 
variety and disorder involved. Since CaCl2 is considered a fertilizer, EPA 
approval is not required for its use. Apple growers have been tank mixing 
it with the commonly used apple pesticide cover sprays to reduce the cost of 
appl ication. 

However, recent concerns about pesticide efficacy, including suspected 
resistance, have questioned the advisability of the past tank mixing prac- 
tices. First, concerns have centered around the spray solution pH. 
According to the manufacturers of CaCl2 the pH of concentrations like those 
commonly encountered can be as high as 10.3 and alkaline conditions may 
reduce pesticide efficacy. Second, since CaCl2 is hygroscopic, concern has 
been raised concerning the weatherabil ity of sprays containing CaCl2. 

Extensive field experiments were conducted during 1980, 1981, and 1982 
to test the efficacy of tank mixed pesticide combinations with various rates 
of CaCl2. Results are given in Table 1. Details have been provided on the 
pesticides investigated, the CaCl2 rates used, and the pests that have been 
studied. Some of the pests were evaluated on apple leaves while others were 
observed on the fruits themselves. Results have been very consistent for 
all pests, pesticides, CaCl2 rates, and for all three years. Almost without 
exception, the control of pests was the same regardless of whether the 
pesticides were applied alone or in combination with 24, 48, or 72 pounds of 
77 to 80 % CaCl2 per acre per year. Under Pennsylvania conditions, 24 
Ibs/acre/year have given good control of corking and bitter pit which deve- 
lop during the growing season. However, in Massachusetts, upward of 72 
Ibs/acre/year are recommended to control internal breakdown of Mcintosh. 

•Reprfffted wifh permission ot the authors from "Consortium tor integrated 
Pest Management Success Stories," Pennsylvania State University, 1983. 



17 



Table 1. Summary of experiments conducted to determine the influence of 
calcium chloride on pesticide efficacy. 









Calcium chl 


oride 










(77-80%) ra 


ites 


Pests 


Year 




Pesticides* studied 


(Ibs/acre/year) 


studied** 


1980 












Experiment 


1 


Polyram BOW 
Penncap M 2FM 
Zolone 3EC 


0, 24, 48 




TABM 
GAA 


Experiment 


2 


Plictran 50W 


0, 24, 4B 




ERM 


1981 












Experiment 


1 


Polyram BOW 
Penncap M 2FM 
Zolone 


0, 24, 48. 


72 


SB. FS, 

TABM, 
SJS, FR 


Experiment 


2 


Plictran SOW 


0, 24, 72 




ERM 


1982 












Experiment 


1*** 


Polyram BOW 
Penncap M 2FM 
Zolone 3EC 
Carzol 92SP 


0, 24, 72 




SB, FS, 

TABM, 
ERM, AS 


Experiment 


2 


Captan SOW 
Dikar 77W 
Polyram BOW 
Guthion SOW 
Guthion SOW + 

Imidan SOW 
Guthion SOW + 

Penncap M 2FM 
Guthion SOW + 

Zolone 3EC 
Guthion SOW + 

Methomvl 1.8L 
Penncap M 2FM + 

Methomvl 1.8L 


72 




SB 
FS 
AS 

TABM 



*Tradenames shown 

**TABM = tufted apple budmoth, GAA = green apple aphid, ERM = European red 
mite, SB = sooty blotch, FS = fly speck, SJS = San Jose scale, FR = fruit 
rots. AS = apple scab 

***This experiment involved 0, 2, and 4 hours of agitation in the tank prior 
to spraying, as a variable. 



18 



EFFECT OF CALCIUM CHLORIDE ADDITION ON SOLUTION pH 
AND ON HYDROLYSIS OF CERTAIN PESTICIDES 

William M. Col i , John M. Clark and Matt Brooks 
Department of Entomology 

Commercial apple grov/ers in Massachusetts typically apply an average of 
6-10 insecticide and 8-12 fungicide dosage eguivalents annually to produce a 
marketable crop. Up to four dosage equivalents of miticide are applied in 
problen blocks and small amounts of aphicides and herbicides are used as 
well, as are various plant growth regulators for fruit thinning, to promote 
early ripening or delay preharvest drop. 

Most growers apply CaCl2 sprays to Mcintosh apple trees, generally as 
additions to their pesticide cover sprays. Technical flake CaCl2, used for 
foliar application, contains 77-80% CaCl2 as well as sizable amounts of 
water, and small percentages of sodium chloride and calcium hydroxide (free 
lime). Many pesticide labels contain warnings about mixing pesticides 
with alkaline materials. Captan, for example, is reported to have a half 
life of less than one hour in pH 8.5 water at 70OF. We became interested in 
what effect, if any, use of CaCl2 would have on solution pH and potentially 
on hydro ''ysis of pesticides and thus on pest control. 

In our earlier tests we monitored the pH of solutions containing the 
equivalent of 5 lbs/A of technical or analytical grade CaCl2, with or 
without the insecticide Guthion*. Concentrations tested ranged from dilute 
to lOX, to simulate a variety of application conditions. It was evident 
that technical grade CaCl2 at 6 and lOX resulted in a moderately to strongly 
alkaline solution pH. The addition of the acidic material Guthion* reduced 
the pH of analytical grade solutions below potentially troublesome levels; 
however, pH of technical grade solutions remained high except at the most 
dilute concentrations. Analytical grade CaCl2 had a less dramatic effect on 
pH due to the presence of less Ca(0H)2 contaminant. We also showed that pH 
of CaCl2 solutions tended to drop over time as the Ca(0H)2 contaminant com- 
bined with CO2 in the air to form calcium carbonate, with an overall reduc- 
tion in solution alkalinity. This reaction can be speeded up by bubbling 
CO2 through the solution. 

Here we report the results of a laboratory study to measure any effect 
of solution pH on hydrolysis of certain representative pesticides. Field 
rate concentrations of azinphosmethyl (Guthion*), methomyl (Lannate*), for- 
metanate hydrochloride (Carzol*) and benomyl (Benlate*) were prepared in 250 
ml of distilled, deionized water containing technical grade CaCl2 at 1,5, 
and lOx concentrations. A control solution containing no CaCl2 and one 
containing lOx CaCl2, which had been saturated for one minute with CO2 prior 
to pesticide addition, were also included. Solutions were sealed and stored 
at 75" F in the absence of light. 

Addition of technical grade CaCl2 resulted in substantial alkaliniza- 
tion of all treated solutions. Although pH of most solutions had returned 
to near neutrality within 24 hours, those containing lOX CaCl2 were still 
moderately alkaline even after 24 hours, as seen in Table 1. Our earlier 



*lrade name 



19 - 



results indicating return of solution pH to less alkaline levels within 24 
hours with addition of CO2 were confirmed, even in solutions which received 
the highest CaCl2 rate. 

Benomyl and methomyl appeared to be most affected by CaCl2 addition, 
because neither of these materials contains strongly acidic components. pH 
of solutions containing either azinphosmethyl or formetanate were least 
affected bv CaCl2 addition. This is because azinphosmethyl is a phosphoric 
acid-containing ester, which would neutralize any added base such as calcium 
hydroxide, while formetanate is formulated as a freely soluble HCl salt. 

As indicated by control values, azinphosmethyl does not appear to be 
very susceptible to hvdrolytic dearadation over time. This material also 
seems to be quite stable over a wide range of pH readings, ranging in these 
tests from about pH 6 to about 9.4. It would seem safe in this case to 
suggest mixing azinphosmethyl with CaCl2 in tank mixes. Formetanate also 
appears to be reasonably stable over time in solution containing no CaCl2. 
However, at the high pH levels resulting from addition of 5 and lOX concen- 
trations of CaCl2, ma.ior loss of parent compound occurred at 6. 12 and 24 
hours. 

In the case of metliomyl. substantial hvdrolysis occurred over time even 
in the absence of CaCl2. Here, it seems that the buffering effect of adding 
some Car.l2 enhanced this pesticide's stability up to a point, although in 
lOX concentrate solutions there was still substantial loss of parent com- 
pound at 48 hours. 

Benomyl also appeared to hydrolyse in control solutions over time with 
only 26% remaining after 48 hours. Degradation was enhanced by CaCl2 addi- 
tion with only about 1/3 of the parent compound and its carbendazim break- 
down product (33%) remaining at 12 hours. 

V/hile the demonstrated substantial loss of parent compound in some "in- 
■.tances may represent a financial loss to growers, it is still unclear at 
:his time that pH-induced pesticide hydrolysis would have any negative 
effect on pest control, particularly since most materials are applied within 
a relatively short time after mixing. However, tractor or sprayer break- 
downs that delay application, or conditions of slow drying where pesticides 
remain in solution for long periods of time may at least affect residues of 
susceptible pesticide. Growers in the Pacific Northwest habitually buffer 
alkaline spray waters, and workers in that region have reported improved 
oest control from use of buffering aoents. 

We hope to look at pest control in the field as the next phase of this 
work. We are particularly concerned about possible degradation of benomyl 
and captan, another funaicide reported in the literature to be prone to 
alkaline hydrolysis, as these materials are included in postharvest dips and 
drenches to which Car.l2 may be added. In this instance, however, we have 
two things going for us. One is the fact that FDA regulations allow only 
use of briner's grade CaCl2. which is much more pure, beino composed of 97% 
CaCl2, and thus would have a less dramatic impact on solution pH. Also, 
since dips and drenches are agitated during application to harvested fruit, 
mixing wi :h CO2 in the air would be expected to be af a maximum with a con- 
sequent drop in pH over time. 



- 20 - 



For now, we can recommend several actions to growers who are concerned 
with possible hydrolysis of pesticides. One choice is to apply CaCl2 
separately from pesticides in tank mixes. Another is to pre-mix CaCl2 
slurries 24 hours prior to adding these slurries to spray tanks. This 
should reduce the dramatic rise in pH. Another option would be to use a 
higher grade of CaCl2 for foliar applications, although the added cost 
fabout $9/100 lbs.) may make implementation of this practice improbable. 
A final option is use of commercially available buffering agents which would 
result in solution pH ranges favoring pesticide stability. 

Table 1. Effect of CaCl2 addition on pH and pesticide degradation over 48 
hours at 75'F 





2 


'/m 


;er 12 hr 


After 


24 hr 


Aft 


;er 48 hr 


CaCl 




% pesticide 


% 


pesticide 




% pesticide 


addit 


ion 


pH 


remaining 


pH 1 


"■emaining 


pH 


remaining 










Benomyl 








Ox 




5.31 


48 


5.50 


39 


5.60 


26 


Ix 




6.00 


41 


7.10 


45 


6.80 


40 


5x 




10.11 


42 


8.50 


37 


8.00 


37 


lOx 




9.40 


33 


8.42 


25 


7.70 


30 


lOx + 


C02 


5.80 


55 


6.42 


50 


6.81 


54 










Methomyl 








Ox 




4.88 


89 


4.92 


20 


4.84 


30 


Ix 




7.38 


42 


6.66 


62 


6.31 


44 


5x 




S.96 


-- 


7.35 


61 


6.98 


21 


lOx 




9.26 


52 


8.23 


28 


7.40 


31 


lOx + 


CO9 


5.32 


87 

A; 


5.65 
n'nphosmethyl 


66 


6.22 


48 


Ox 




5.65 


109 


6.78 


108 


6.48 


82 


Ix 




5.84 


71 


5.84 


74 


5.84 


75 


5x 




7.08 


80 


7.39 


59 


6.74 


63 


lOx 




9.18 


63 


8.86 


67 


8.37 


73 


lOx + 


CO2 


6.04 


86 


6.08 
Formetanate 


96 


6.08 


88 


)x 




4.54 


91 


4.71 


88 


4.72 


84 


ix 




5.99 


78 


6.50 


79 


6.67 


55 


5x 




7.30 


57 


7.33 


47 


7.66 


22 


lOx 




8.08 


41 


7.92 


14 


7.76 


8 


lOx + 


CO2 


5.79 


95 


5.88 


105 


6.12 


102 



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 



Volume 50, No. 3 
SUMMER ISSUE, 1985 

Table of Contents 

Compatability of Selected Apple 
Rootstocks with Massachusetts Soils 

Predicting the Keeping Quality of 
Macintosh Apples from Preharvest Mineral 
Analyses of Fruit 

Biological Control of Weeds 

Update on the Relative Toxicity of 
Orchard Pesticides to the Predator Mite 
Ambiyseius fallacis 

Putting Theory into Practice 

The Soft Fruit Industry in England 

Parking Tips for Roadside Markets 



Issued by the Cooperative Extension Service, E. Bruce MacDougall, Dean, in further- 
ance of the Acts of May 8 and June 30, 1914; United States Department of Agriculture 
and County Extension Services cooperating. The Cooperative Extension Service offers 
equal opportunity in programs and employment. 




COMPATIBILITY OF SELECTED APPLE ROOTSTOCKS WITH MASSACHUSETTS SOILS 
Peter L.M. Veneman, Department of Plant and Soil Sciences 

Orchard Soils 

A good orchard soil should be deep and well aerated, yet capable of 
holding sufficient moisture to meet the water needs of fruit trees, even 
during prolonged dry spells. Soils with clayey or compacted subsoils lack 
large pores, which may result in a restriction of the oxygen supply to the 
roots. Tree roots often tolerate some submergence during the dormant 
season, but this water should have dissipated by the time growth starts in 
the spring. Tree growth and fruit production otherwise tend to be poor on 
such soils. Although some of these limitations can be overcome tiiy soil 
modifications, such as artificial drainage or by subsoil loosening, most of 
these measures are expensive and in the case of compacted subsoils effective 
only for a limited time. 

Prior to purchase of any trees the soil should be examined by a 
qualified soil scientist to determine whether or not the soil is suitable 
for growing fruit trees. Soils which have orange-reddish and grayish 
mottles, or which have predominantly gray colors within 3 feet of the soil 
surface most likely have problems with excessive seasonal wetness and should 
be rejected as an orchard site. Gravelly and coarse sandy soils on the 
other hand lack sufficient water storage capacity and are subject to drought 
during prolonged dry spells. 

The ideal orchard soil should have a dark, organic-rich topsoil. The 
subsoil should be capable of retaining sufficient amounts of water to 
sustain unlimited grov/th even during prolonged dry periods, while on the 
other hand being permeable enough to rapidly conduct excess soil water. 

Careful observation of the natural vegetation growing on or adjacent to 
the site selected for the orchard can be helpful in determining the suitabi- 
lity of the soil for fruit trees. Pitch pine and scrub oak indicate gra- 
velly soil which is excessively drained and subject to drought. Red maple, 
alder, and willow indicate a soil which is poorly drained and excessively 
wet. Sugar maple and white ash do best on a deep fertile, well-drained soil 
of good water-holding .capacity. 

Matching Rootstock and Soil 

Size-controlling rootstocks in general are more demanding than seedling 
rootstocks in respect to drainage, depth of soil, and water holding capa- 
city. Therefore, when deciding on which rootstock to use, it is very impor- 
tant to know the soil type(s) of the land to be planted. The proper match 
between rootstock and soil may be the difference between the success or 
failure of the planting. 



- 2 



Experimental plantings, matching various rootstocks with representative 
Massachusetts soils, are presently being conducted throughout Massachusetts 
but no definite results on yield differences are available as yet. Based on 
past experience we can make some general recommendations regarding the per- 
formance of certain rootstocks on various Massachusetts soils. 

The first step in matching the rootstocks and soil is to determine the 
soil type{s) for the land to be planted. Soils information generally is 
available from the U.S. Department of Agriculture - Soil Conservation Service 
office in the form of soil survey reports. If no soil map is available, an 
on-site inspection by a qualified soil scientist will provide the necessary 
information. On-site investigations often are preferred because localized 
wet or droughty spots may exist within fields that are otherwise well suited 
to apple production. These less desirable areas may be too small to be 
indicated on the standard scale soils map. Your local Extension Service 
office can provide you with the names of qualified soil scientists within 
your area. 

The soil series currently recognized in Massachusetts have been grouped 
in 6 soil suitability groups (Table 1). Keep in mind that these suitability 
groupings are based on internal soil characteristics. External properties 
such as landscape position and a drainage potential are not considered, 
therefore, soils at certain locations, although placed in a favorable 
grouping, may not be suitable for apple production. 

Lastly, refer to the tentative guide for rootstock/soil compatibility 
in Table 2 to determine which rootstocks are most suitable for your soil 
conditions . 



- 3 



Table 1. Grouping of Massachusetts soils according to suitability for apple orchards, 



Group 1. Gravelly or sandy soils with a tendency to drought. 



Carver 

Dukes 

Enfield 



Evesboro 
Groton 



Hinckley 
Merrimack 



Plymouth 
Quonset 



Suncook 
Windsor 



Group II . Gravelly or sandy soils, without the tendency to drought 



Agawam 
Canton 
Copake 



Essex 
Gal estown 
Gloucester 



Haven 

Hinesbury 

Katama 



Lincroft 
Montauk* 
Oakville 



Poquonock* 
Warwick 



Group III 



Good, deep 
capacity. 



Berkshi re 
Brookfield 
Charlton 
Chatfield 



soils with average to good drainage and a good waterholding 



Cheshi re 
Chilmark 
Col rain 
Dutchess 



Had ley 
Hartl and 
Lenox 
Narragansett 



Ondawa 

Pittsfield 

Pollux 



Riverhead 
Unadil la 
Yalesville 



Group IV. 



Good , but 
rooting. 



somewhat shallow soils with hardpans or bedrock that prevent deep 



Bernardston 
Brimfield 
Broadbrook 
Hoi lis 



Hoi yoke 
Lyman 
Marlow 
Meckesville 



Mel rose 
Mill is 
Nantucket 
Nassau 



Newport 
Paxton 
Shel burne 



Stockbridge 

Suffield 

Wethersfield 



Group V . Soils that tend to be wet for short period of time, but usually not during the 



growing 


season . 








Acton 


Buxton 


Ludlow* 


Podunk 


Sutton 


Amenia 


Deerfield 


Matawan 


Rainbow* 


Tisbury 


Amostown 


Eldridge 


Ninigrit 


Scio 


Wauchaug 


Belgrade 


Elmwood 


Peru* 


Scituate* 


Winooski 


Birchwood* 


Hero 


Pittstown* 


Sudbury 


Woodbridge 


Buckland* 


Klej 









Group VI . Poorly drained soils