&^0V lO G\c^^- DDDnnnnnaDDDDnnnDnDnnDannnna a a D a D n D D D D D D D Q D D D n D a D a a D D a D D a D p D p p D P D □ a D a a p p p p Bi lASft7 sci^f*^ UNIVERSITY OF MASSACHUSETTS LIBRARY P D P a p p □ □ p p p p a a p p p p p p p p p 8 p D D P D P D D D a a a a D p p p p n -^H pppppDPPPDPPPPPPnPDDDDPPPna 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 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. Tree training l to n> T3 CO Q< t* O .^. c+ 3 -) U3 fD to a> S o (T> -) o a> s -! a. fU _i. 3 Ol U3 CO CO O c O 5 e —* 3 CLIO o r+ o zr o Ol ^ r+ -J • r+ or tT> 3 Ol C_|. O -5 —t. r-t- '< rc r+ -J re fD CO OJ •-D CO ■o c 3 cu ^ -5 ■o a> O l-H 1— 1 c -i CO -> o — *• —»• r+ — j> -J O 3 3 —J CO ri- fD a> o O —J -) ri- C r+ <-•• Ol fD al a. -^> -^. Ol tD al 3 O O T *< ^. o o 3 3 Crt CO fD 3 oo o c: c O. 3- 3" Q. Ol fD .j> CO CO o o . — . - — ^ ^ — ^ —J c ^— X ^-^. 3 CO 3 QJ CO CO 3 o o 3 T3 C o 3 . — ^ C 3 1 -J 1 3 -5 1 CO ^-^^ CO o — -• CO T3 •o 3 1 -J -J CO -J — ^ v.^# ■a c ^J o^ en 00 00 -^ CO 00 ^J 00 -J 00 00 X X X X X X X X X X X X X -p» CJ1 tn CO oo *» GO oo 4^ oo -Pi 00 00 1— • I—" ►— ' -fi -t» 1 — ' 42. -Pi 1 — ► -p. 1 — ' -pi -p» en 00 00 o o en o o cn O en o o o 1 — ' o 1 — ' o 1 — ' 1 — ' oo 1— ' O r\j ro 1 — ' 1 — • INi o ro 1 — t ro X X X X X X X X X X X X X 1 — ► 00 1 — » 00 1 — » 00 o 1 — * 1 — » 00 r>o o o 1— » r\3 o 00 o (\3 O 1 \ 00 t— » i 1— ' 00 1 — ► 1 — ' 00 t— » r\3 o 00 1 — • 00 1 — ' 00 1 — ' t— • 00 I—" -fi CO CaJ CTl •-J -p> 0^ r\3 cn ro ro -P» ro -p. ro 1 — ' ro 4^ ro ro ro 4=» ro -P» 4^ 1— > 1 — ' cn U3 I—- cn 03 1 — * 1 — ► CO 1 — ► o ro 1 — t (— » CO 1 — t I—" CO cn ■•£> I—" 1— • 1 — > -p. 1— • 1 — ' 1 — ' CO 1— • I— ' CO cn 1 — ' 4i t — ' -^ 00 cn 1 — • 1 — ' 1 — » 4=> 1 — ' cn --J 1 — ' X X X X X X X X X X X X X ro CO ro ro ro ro ro cn ro cn ro CO ro CO ro cn ro ro ro cn ro CO ro cn ro cn 1 — » ro t — » -p» 4^ 1—' 1 — » o ro CD CO 1 — ' ro cn 1 — ' o ro 1 — ' o ro 1 — ' -pi 1— • 1 — » o ro 1— • ro cn 1 — » o ro 1— * o ro 1 — ► cn 1 — » cn cn 00 CO I—* cn 00 1 — ' 00 1— » cn 00 cn 1— ' CXI 00 X X X X X X X X X X X X X ro -Pi CO CO ro CO ro cn ro ro -P« ro ro cn ro CO cn ro 4i ro ro cn 1 — ' 1— » CO 1 — ► ro 1- CJ CD -TO m — ( O" -1 — ' C tK — * ft) e T -J — '• fD 3 o n JLl n T3 -■• c O fD t/1 fD -h c a» 3" -) -5 3 fD cr C O CL CU -J- c a. n r+ —.-a TD Q. 2 -..-o — • (V o o — • Oi CL fD Z3 — » o CD a/ cr Ol X c -h -htd fD ■X) 00 ^1 a> :2 c: J> o fD D -o o O) fD T3 a. n — -^ — < Cfl < fD — <• — *. n S a. OI T3 a> o ■o o fD o -1 ~i o. r-f — *• ~> J fD CQ fD 3 tn fD fD IX) v£) CU 00 00 D 4^ oo o d c: ->> rj 3 I/) CO !r« ■o "O -> -) Ol V: ^ fD fD Q. O. •X) fD oo 00 oo 00 CU -p" CO rv) t — • -t s* I o -o _l. -, -, (/) CT" — '• — '• vO fD i/> 3 -) O Ol r-t- -■• ^ -- -••-)-> cr -I. -<• fD i/i 3 -) O O) <-f -•■ ■-< — O on Ol <-n en tn I o -o -•• —\ ~i cr -^. -■• fD LO 3 TOO) ^ — ' CU O en en o r\i -t» *i O O CD ro -Pi -P» O O O »-• .C» I— ' o o o o 00 eD eo eo eo •— • en oo eD 00 oo -ti --J cn ^-J 00 --J eo en 00 00 CO CjO en o ro O O H^ 1— ' -> CTl C3-1 -t^ -fi oo • • • • • • « • • • • ■Ci -J en en oo o en o o o o O o >— " 1— ' O O -ti kO en CD o ^J en O -e> -• H- O ro >-' a en eD 00 CTi O ro 00 on CT> 00 CTl CL> fD <-+ oc O" O -t) fD • ~i O) c -) <-•■ — *■ — *■ -) r-t- n fD 02 fD I/) cr 00 z r-t- fD CU O -) Q) 3 . a> -i -o fD -■• — ' -h rj fD -1 CD jJi CU 13 03 m 3> oo ro oo cn XI + en 9*. d a> a. cr fD -i -o O fD Ol -1 "O <-f <-f c -) ~) fD fD fD a. OO C J. cr fD -> 3 fD O a> fD eo O « r-t- _,. ■o • -o _J fD o O 3 CX — *. t/) fD CU f) fD 3 fD eo — i. LO r-t- CU 3 <-f r+ 3 fD fD (/I 3 oc o I eo ■O 3 CU o< o 3 n O) 3 CL CU 3 Q. O 3 3 fO Q< 3 a- oc c 3 CO ■o 3 Ol oc fD cx 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 Observat 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 0 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. Summary 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 0 Magnesium 5 1 Boron 17 0 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. Approximate 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 Sciences 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 reduced 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 Growers 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, unsuitable for tree fruits, unless artificially drained, Adrian Au Gres Berryland Biddeford Birdsall Brockton* Cabot* Carlisle Enosburg Fredon Freetown Hal sey Ipswich Kendal a Leicester Limerick Lyons Mansfield* Maybid Menlo* Munson Norwell* Palms Pawcatuck Peacham* Pipestone Pompton Raynham Ridgebury* Rumney Saco Saugatuck Scitico Scarboro Stissing* Swansea Swanton Walpole Wareham Westbrook Whately Whitman* Wilbraham* *Denotes presence of a hardpan Table 2. An approximate guide of rootstock/soil agreement. Rootstock Soil suitability groups II III IV VI Dwarf M.9, M.9A, or virus-tested M.9 Semi -Dwarf M.26 Interstem M.9/Alnarp 2 Interstem M.9/Seedling Interstem M.9/M.13 Interstem M.9/MM 111 Interstem M.9/MM 106 MM 106 M.7 or M.7A X X X X X X X X X X X X X X X X X X X X X X Vigorous Alnarp 2 MM 111 Seedling X X X X X X X X X denotes compatibility of rootstock and soil group PREDICTING THE KEEPING QUALITY OF MCINTOSH APPLES FROM PREHARVEST MINERAL ANALYSES OF FRUIT William J. Bramlage, Sarah A. Weis, and Mack Drake Department of Plant and Soil Sciences If the storage potential of apples could be predicted accurately at harvest, the fruit could be stored and marketed within these potentials. Lots of fruit with potential for long-term storage could be stored long- term, ones whose potential is not as good could be marketed in early- to mid-winter, and ones with little storage potential could be marketed in the fall. In this way the grower could make maximum use of his fruit and the consumer could benefit by purchase of better quality fruit. During the past 30 years a large volume of research has established that mineral compostion is related to keeping quality of apples by influencing the onset and rate of ripening, but especially by determining the occurrence of physiological disorders after harvest. Early research focused primarily on bitterpit, which is caused by a deficiency of calcium (Ca) in the fruit, but it is now recognized that many apple disorders are influenced, if not caused, by adverse mineral compostion of the fruit. The predictability of storage disorders from preharvest mineral analyses was first proposed in England; methods of fruit analyses and pre- diction from the results were then developed there. For a number of years, a large cooperative storage (East Kent Packers, Faversham, Kent) has used predictions from fruit mineral analyses to schedule storage withdrawals for its Cox's Orange Pippin apples. Since value of the apples generally increases with later marketing, growers who maintain proper mineral levels in their fruit are rewarded by later marketing of their fruit and the corresponding higher prices paid for them. During the 4 years 1979 to 198?, we conducted extensive surveys to determine (1) the effects of minerals in Massachusetts-grown Mcintosh apples at harvest on their keeping quality; and (2) if it is possible to predict the keeping quality of our apples from preharvest mineral analyses. Our findings in regard to the first question have been reported earlier ( Fruit Notes 48(4) :4-8), and can be summarized in one sentence: "...inadequate Ca in fruit is the primary nutritional factor influencing quality of Mcintosh apples in Massachusetts, and this factor is expressed mostly in the occurrence of breakdown after storage." We found that many orchards were producing Ca-deficient fruit which therefore possessed lessened potential for long-term storage. Here we now report our findings about predictability of keeping quality from mineral analyses. We used 2 different approaches to prediction. First, we used a scoring system similar to the one developed in England, which gives each sample a "score" for its mineral composition, and this score is then used to predict the keeping quality of the fruit. The score is based on the concentrations of N, P, K, Ca, and Mg in the fruit 2 weeks before harvest. A preliminary report (Proceedings of the Massachussetts Fruit Growers Association 88:46-56) concluded that a prediction based on such a score was feasible for our apples, but also that accuracy of the prediction was quite variable. - 6 - When results of all 4 years of data were assessed, it was apparent that this approach was reasonably accurate when only low scores (which indicate excellent storage potential) and high scores (which indicate very poor storage potential) were considered. However, it did not provide useful information about samples which had intermediate scores. Our second approach was to produce equations that described the rela- tionships between mineral composition and keeping quality in mathematical terms. Initial indications were that this was the better approach (Proc MFGA, cited above). When the 4 years of data were fully evaluated, this initial assessment was reaffirmed. The equation that we developed was a more accurate predictor than was the scoring method we used. Furthermore, it could be used to predict keeping quality from any mineral composition, not from just the very high and very low ranges. Our results showed that because Ca was the only element that was generally affecting keeping quality of the apples, a mineral analysis was needed only for Ca to make a prediction. The other elements in our survey-- N, P, K, and Mg--did not need to be measured for our fruit. In a separate study we tested the value of including measures of fruit maturity and fruit size in a predictive equation, since storage life is reduced as apples become large and are harvested at a later maturity. This study indicated that inclusion of a score for starch concentration in the apple and inclusion of a measure of fruit size at harvest both could improve the accuracy of a prediction based on Ca concentration in the fruit ? weeks before harvest. To be able to predict potential keeping quality of commercial lots of apples at harvest from mineral analyses, there must be the capability for gathering, preparing, and analyzing representative fruit samples rapidly. Our studies are all based on sampling apples 2 weeks before harvest. If fruit samples could be taken earlier in the growing season it would allow more time for analysis, but research in England has shown that the earlier fruit samples are taken, the less likely they are to represent the mineral content at harvest. Leaf analyses cannot substitute for fruit analyses. While they are good measures of mineral status of trees, leaf analyses are of little value in portraying the mineral status of fruit, especially that of Ca . Thus, use of prediction capabilities requires the ability to obtain results from a testing laboratory in a very short period of time--within 2 weeks after taking the samples from a tree. At present no laboratory in Massachusetts is capable of doing this. This has presented a dilemma to us. On one hand, we know that we can predict with acceptable accuracy how well Mcintosh will keep after harvest, but we do not have the facility for producing the needed analyses. On the other hand, we are working with a rather simple problem: Ca deficiency is the basis for the prediction. Should our efforts be directed to establishing a facility for analyzing fruit and predicting storage life, or would it be better for us to continue to pursue methods of avoiding and correcting Ca -deficiency? To this point we have chosen the latter course, and have continued to try to improve preharvest and postharvest treatments to ensure that fruit possess sufficient Ca at harvest for maximum posthar- vest life. '^ 7 - However, fruit mineral analyses could be quite useful to a fruit grower if for no other reason than to measure the adequacy of his Ca treatments. It could also indicate whether or not a postharvest Ca drench is needed. Although no fruit analysis service is available in Massachusetts, the Analytical Laboratory in the Department of Plant and Soil Sciences of the University of Maine is offering a commerical apple fruit testing service. Their capacity to analyze fruit within 7. weeks is limited, but within this limit the cost of an analysis is $l?.On per sample. For anyone interested in this service samples should be taken 2 weeks before the projected harvest date. A sample would consist of 20 apples, one from each of ?0 trees, and these trees should be representative of the block which is being tested. It is essential that the fruit he uniform in size, between 2.7 and 2.8 inches in diameter. These fruit will be analyzed for Ca , K, P, and Mg . A problem that will have to be resolved is how these samples can be transported to the laboratory. We would suggest that any grower who is interested in this ser- vice should contact Mr. Bruce Hoskins (207-581-2917) well before sampling so that necessary arrangements can be made. There is considerable interest among research workers in the potential for predictions from mineral analyses. We have not encouraged establishment of a commercial laboratory in Massachusetts because we believe that Ca defi- ciency is correctable. However, now that fruit analyses are available through the University of Maine laboratory, growers have the opportunity on a limited scale to assess the mineral status of their fruit in time to make critical decisions about the ways in which they will be treated and stored after harvest. This may be a direction for the future. POMOLOGICAL PARAGRAPH Weeds are reservoirs for virus. Tomato ring spot virus (TmRSV) can cause disease of apples, peaches, cherries, grapes, raspberries, blueberries and strawberries. For example, TmRSV is associated with a disease known as apple union necrosis and decline and Prunus stem-pitting disease of peach. Studies in Pennsylvania show that 18 species of broadleaf weeds including common chickweed, henbit, dandelion, common plantain, wild strawberry, sorrel, red clover and oxalis were all natural hosts for TmRSV. Further studies showed that (1) TmRSV in dandelion is correlated with Prunus stem-pitting diseases of peach; (2) dagger nematodes that feed on the roots of a TmRSV-infected dandelion and then on the roots of a peach tree can transmit the virus to that peach tree; and (3) TmRSV can be carried by dan- del ion seeds . How do these results apply to growers in Massachusetts? TmRSV also is of concern in Massachusetts, thus the control of dandelions to insure good bee activity should also help eliminate a major source of the virus. - 8 BIOLOGICAL CONTROL OF WEEDS William J. Lord, Department of Plant X Soil Sciences In recent years attention of weed scientists has been directed to biological control of weeds using insects, pathogens or allelopathy. Successful examples of weed control with insects or pathogens can be cited and include control of cactus in Australia by a moth borer imported from Argentina, control of St. Johnswort in western United States by leaf-eating beetles, and use of pathogens to control northern jointvetch in rice fields and strangler vine in citrus orchards. Plants may release chemicals ( al lei opathics) which are harmful or bene- ficial to other plants and to pests that affect the plant. The release of these chemicals by either living plants or their residues is called allelo- pathy. Studies have been directed toward the use of allelopathy. A.R. Putnam, Department of Horticulture, Michigan State University, is researching the use of cover crops or companion crops whose residues can provide mulch that chemically suppresses the germination and/or growth of weeds under fruit trees (12th Ann. Rpt . , Michigan State Hort. Soc . 1982, pp. 193-196). His studies show that residues from fall -pi anted cover crops of Tecumseh vvheat (spring or fall -killed with herbicides) and Balboa rye ( fal 1 -ki 1 led) reduced both weed density and total weed biomass during the following growing season. In contrast, Garry oat (fall-killed by cold weather) residue appeared to stimulate weed germination and Balboa rye resi- due (spring-killed with herbicide) was not toxic to weeds. Other experi- ments indicated that Bird-a-Boo sorghum or Monarch sudangrass mulch provided weed biomass reduction of approximatl ey 90% and 85%, respectively. The weed species encountered in both the cover crop and mulching experiments were primarily annual s--large crabgrass, common ragweed, common 1 ambsquarters, ladysthumb, green foxtail, and mousear chickweed. Perennial fescue species also were partially controlled. Putnam concluded that selected cover crop residues or mulches can pro- vide excellent suppression of a number of annual weed species but that long- term studies must be conducted to determine effects of these cover crops or mulches on fruit trees. A major disadvantage of mulch is that it provides a favorable habitat for mice. UPDATE ON THE RELATIVE TOXICITY OF ORCHARD PESTICIDES TO THE PREDATOR MITE AMBLYSEIUS FALLACIS Susan L. Rutkewich and Ronald J. Prokopy Department of Entomology In past issues of Fruit Notes we cited the relative toxicity of orchard pesticides commonly used in Massachusetts apple orchards to the mite preda- tor Amblyseius fallacis in both laboratory (Vol. 43 (5): 14-18; Vol. 44 (5): 6-8) and orchard settings (Vol. 43 (4): 5-8). We have shown that Massachusetts field populations of A. fallacis, an important predator of red and two-spotted spider mites, are highly susceptible to field concentrations of some pesticides such as Lannate* (methomyl), Cygon* (dimethoate) and the synthetic pyrethroids (SPs), but can tolerate other pesticides like Guthion* (azinphosmethyl ) , and Thiodan* (endosul fan) . The degree of tolerance or resistance this predator possesses can vary from region to region depending on the history of chemicals applied in each area. Resistant strains of A_^ fallacis have been found in orchards across the country. In Michigan, New York, New Jersey and North Carolina, several field populations of A^. fal lac is have been screened for resistance to various pesticides. In' particul ar , at the Pesticide Research Center and Department of Entomology at Michigan State University, Brian Croft and others have evaluated pennPthrin-( Ambush* , Pounce*) resistant strains of A. fal lac is for cross resistance to other SPs and for resistance to insecticides in other classes, i.e., organophosphates and carbamates. Successful establish- ment of resistant/cross resistant predator mites in the field would provide an important tool for IPM programs across the country. What alternatives exist for encouraging predator mite populations today? At present the most effective strategy a grower can undertake is to select pesticides and application time which have minimal effects on preda- tors. Pesticides of high or moderate toxicity are not recommended in orchards after bloom. Pesticides can be detrimental to A. fallacis if they are applied when the predator is in the understory, i.e. diinng spring and early summer, and later when the predator has moved up into the tree, i.e. July through September. Here, we present the latest compilation of the relative toxicity of pesticides commonly used in Massachusetts apple orchards to the predatory m1te A. fal 1 acis . The toxicity ratings have been arranged according to each state where the infomation was obtained. The ratings provide comparison of the predator's susceptibility to pesticides in different geographic loca- tions. *Trade name - 10 - Table 1. Relative toxicity of commonly used pesticides to A. fallacis Location Material Insecticides chlorpyrifos 50WP methomyl l.aEC carbaryl SOWP phosalone 25WP phosalone 3EC demeton 6EC fenvalerate 2.4EC pennethrin 3.2EC dimethoate 2.67EC dimethoate SOWP oxamyl 30WP diazmon 50WP phosphamidon 8EC amitraz oxythioguinox 25WP ennosulran 50WP phosnet 50WP azinphosmethyl 50WP methyl paratnion 2FM methyl parathion 2EC methoxychlor 50WP Acaricides Acaralate* 2EC formetanate 925? dicofol 35WP cyhexatin P^OWP propargite 30WP fenbutatin-oxide 50WP Fungicides Lime sul fur difol atan 4EC dinocap 25WP benomyl 50WP dikar 80WP glyodin-dodine 37-22WP glyodin 30EC dodine 65 WP maneb 80WP thiram 65WP dichlone 50WP captan 50WP ferbam 76 WP maneb-zinc 80WP Polyram 80WP Herbicides ammonium sul f amate paraquat 2EC glyphQsate 2EC simazme 80 WP dal apon WP MASS High High High High High High High High High High Mod Low Low Low Low Low High Mod Low Low Low NY MICH NC NJ Relative toxicity High High High High High High Mod Mod Mod Mod Low Low Low Low Low High High Low Low Low Mod High High High High High Mod Low High Higf- Mod Low Low High Mod Low High Mod _ _ Mod* Low Low Low Mod Mod Low _ _ Low - - Low Low Low Low _ Low - _ Low .ow _ Low .ow Low .ow .ow _ -OW _ " — Low High High - - High _ _ Low Low _ Low - - High High High Low Low Low Low High High Mod ^Sterilizes predators - 11 - PUTTING THEORY INTO PRACTICE William J. Bramlage, Department of Plant and Soil Sciences During the winter of 1979, the East Mailing Research Station, Kent, England initiated an unusual project: development of a demonstration apple orchard that incorporates the practices believed by the East Mailing research staff to be most desirable for successful establishment and deve- lopment of an orchard of 'Cox Orange Pippin', England's most important dessert apple. A detailed examination of the development of this orchard provides a unique view of the current thinking of England's leading pomolo- gists. The site for this orchard is on deep, well-drained, fine sandy loam and is surrounded by windbreaks of alder and sweet chestnut trees. In July, 1979, the site was subsoiled to a depth of 20 inches, plowed with a chisel plow, and leveled. The rows were laid out and the strips in which the trees were to be planted were fumigated by injecting Chloropicrin at 25 gallons per acre under 41/?-foot wide strips of clear polyethylene. The fumiga- tion was done because this was fornier apple orchard land with a known replant problem caused by a buildup of soil organisms harmful to apple roots. The polyethylene sheets were kept in place until planting to protect soil structure. In December, 1979, two ll/4-acre blocks were planted, one on M9 and one on MM106 rootstock. Trees had been budded at \?. inches, and developing branches ("feathers") were removed from the bottom ?7 inches of stem; above this point they were pinched at U/;? inches of length and then allowed to develop. 'Cox' on M9 were planted at 11 1/? x 8 feet, 481 trees per acre, and ones on MMlOfi were planted at 11.5 x 17 feet, 220 trees per acre. 'Discovery' and 'Spartan' were planted as pollenizers, alternating at every sixth tree in a row and being staggered in adjacent rows to produce diagonal rows of identical cultivars. Holes were dug with a tractor-mounted auger, each tree was immediately staked with B-foot spindle stakes, and trees were carefully tied to stakes with plastic tubing. In late February the central leaders were headed to a vegetative bud about 4 inches above the uppermost "feather". M9 trees produced some bloom and were defruited shortly afterward. In June, the second, competing shoot was removed from all trees. The following February, the central leader of each MMin9 tree was tipped, and all competing leaders were removed. The central leader of each M9 tree was tipped, as were 4 other leaders. In July of this second year the more vigorous branches were tied down to encourage fruiting, and the following winter all remaining branches were tied down. To further suppress vegetative growth, by stimulating flower bud formation, daminozide was applied in July, 1980 at 18 lbs. per acre, and in July, 1981 at 13 lbs. per acre. Assistance of Mr. G.C. White of the East MalTTng Research Station in the preparation of this article is gratefully acknowledged. 12 It is intended to maintain these trees at a height of about 71/2 feet, with a well-defined "fruiting table" at ? 3/4 feet. The tip of this central leader tree will not be allowed to become dominant, by continually cutting it back to a suitable weaker leader. Before planting, the entire orchard floor was sprayed with a herbicide mixture of simazine and paraquat, and follow-up spot applications of diuron were used to kill persistent weeds. A grass alley was then established (before planting) and remained until the start of the 1982 season, when it became apparent that soil structure was collapsing, and at one point in 1983 the leaves on the trees wilted. To correct this problem the alleys were again subsoil ed in August, 1983, and grassed down with perennial ryegrass in the spring of 1984. These grassed alleyways are a temporary measure and will be killed when soil structure and organic matter are judged to again be satisfactory. An overhead irrigation system was erected in the orchard. The risers for the system are 51/2 feet high in the M9 block and 9 3/4 feet high in the MMine block. In 1982 and 1983 this system was used to prevent frost damage and during the dry summers of 1983 and 1984 irrigation was an impor- tant contributor to the yields obtained from these blocks. In 1981 it was apparent that bloom on the pollenizer trees was inade- quate, and this problem reoccurred in 1982 and 1983. To overcome the problem a bouquet of bloom was placed in the center of each group of 5 'Cox' trees. These bouquets were kept in water in a plastic bag that was looped around a nail on the stake supporting the tree. A fresh bouquet was placed in the bag after 4 days. By 1^84 pollenizer bloom was sufficient to avoid this task. Fach year hives of bees were placed in the orchard on the south side near the windbreak when 10-15% of the bloom was open. Yield from these trees was about 8 bushels per acre in 1981 (the 3rd growing season) regardless of rootstock. In 1982 the M9 and MM106 trees produced 172 and 176 bushels per acre, respectively. In 1983, M9 and MM106 trees yielded 334 and 290 bushels per acre. M9 and MM106 graded out 82% and 87% Class 1 fruit, repectively, in 1983. Since the average yield of 'Cox' in England is only 225 bushels per acre, it is evident that this orchard, in only its fourth year, is performing very well. In 1983 the spray program cost the equivalent of $350 per acre. Almost half of this cost was accounted for by nutritional and growth regulator sprays. These consisted of 4 applications of a commercial gibberellin (fiA4+7) spray used to improve fruit finish, and 5 applications of a commer- cial phosphorus mixture, used to improve storage quality of fruit. Management decisions for this orchard are made by a committee of East Mailing researchers headed by the Director of the Research Station. The industry is kept well informed of the orchard's progress, problems that are encountered, and responses that are made to correct the problems, by an ongoing series of articles that appear frequently in The Grower, a commer- cial horticulture weekly magazine. This unusual project not only allows the growers to observe modifications that can be made when unexpected problems arise. It is a fine example of "putting theory into practice." - 13 THE SOFT FRUIT INDUSTRY IN ENGLAND Wi 1 1 iam J . Rraml age Department of Plant and Soil Sciences The soft fruit industry in England is under continual pressure from European countries, but the intensity of this pressure varies with relative values of currencies. When the value of the English pound sterling is low, imports from Europe decline, but when the pound's value is high European soft fruit--both fresh and processed--can quickly flood the market. Therefore, fortunes of the industry can fluctuate dramatically for reasons completely beyond the control of the fruit growers. Table 1 shows the estimated size of the soft fruit industry in the United Kingdom in 1980, which is fairly typical of recent years. Most of this production is in England except for that of raspberries, where two- thirds of the crop is grown in Scotland. Approximately 60% of the strawberries are grown for fresh market, and 40% for processing. In contrast 30% of the raspberries are grown for processing and virtually all of the blackcurrants, gooseberries, blackberries, loganberries, and currants are processed . Table 1. Approximate total production areas and yields of soft fruits in the United Kingdom (England, Scotland, Wales, and Northern Ireland). 1980. Crop Area (acres) Production (tons) Strawberries 20,000 54,400 Raspberries 10,750 21,200 Blackcurrants 10,500 18,400 Gooseberries 2,875 7,900 Blackberries 1,425 4,400 Loganberries 450 1,000 Red and white currants 425 900 These fruit are all expensive to establish and to grow. Their produc- tion problems can be summarized as ones of obtaining good sites, using healthy plant material, and rigorously controlling weeds, insects, and diseases. Plant material is provided through a system similar to that described for apples (Fruit Notes 50(1) :l-5) . The biggest cost, however, is in harvesting and marketing. An effi- cient machine harvester has been developed for blackcurrants, but its cost is quite high. The other soft fruits are predominantly hand harvested by local labor. PYO has become very popular for soft fruits, but a good PYO business requires careful organization and management, and provisions for parking, toilets, and picnic areas. - 14 - Strawberry production for the fresh market has remained strong in England. European imports discourage early-season production although small volumes are produced under plastic tunnels for early local marketing. Main- season marketing has been strengthened by establishment of cooperatives, a move dictated by concentration of wholesale buying into fewer and larger outlets that demand large volumes of uniform, attractive fruit. These markets also require properly cooled fruit, and cooperative facilities can make this feasible. Cooperative marketing is the only way small growers can compete in this arena. PYO production of strawberries has been growing espe- cially in holiday areas of the country. However, strawberry processing has been declining due to both economic factors and changing eating habits of the Engl ish people. Cane fruits are growing in popularity for PYO sales, but very little is otherwise marketed fresh because of the high cost of harvesting and the need for proper cooling if volume marketing is to be attempted. The black- currant, a fruit with which most Americans are unfamiliar, is popular in England primarily as a processed product. Blackcurrant production is highly concentrated since the mechanical harvesters developed for this crop are only efficient on large acreage. Because the capital investment in har- vesting is high, blackcurrant growers have negotiated long-term contracts with processors. Gooseberries and currants have lost favor with consumers in recent decades and are dwindling as commercial commodities. The long-term prospects for the soft fruit industry in England seem to rest with further development of fresh fruit sales. There is considerable interest in developing new varieties and production methods to lengthen the harvest season for these crops. Expansion of fresh fruit sales will prob- ably be required to balance continued erosion of the processing market to make this a stable industry. 15 - PARKING TIPS FOR ROADSIDE MARKETS* Ample parking is a major concern for most new farm markets (and some old ones too!) Today's shopper likely will not stop-to-shop if there is no safe convenient parking area. Carefully planned customer parking offers great opportunity for building up your trade. It is very important to understand the handling of the traffic flow into and out of the parking lot. 1. Allow a ratio of 4 square feet of parking space for each square foot of market size. For example, a 40 x 50 ft. building (2,000 square feet) would require approximately 8,000 square feet or nearly one-fifth acre of land for parking . 2. Allocate one parking space (about 400 square feet) for each $100 sale. 3. Provide 15 parking spaces for each 100 cars expected daily. All of these general rules are good, but the important consideration must be the convenience of the customers. Parallel parking space should be 22 feet long by 10 feet wide. Parallel parking is awkward and wastes space, but is used sometimes to fill in odd areas. A combination of 90 degree angle and parallel parking often makes the best use of small or irregular lots. Parking at 90 degrees to a curb or fence accommodates the most cars in the lot. Minimum practical dimensions for a parking stall are 10 x 20 feet. With 90 degree parking, two-way traffic aisles are best. Where lots are 60 to 70 feet wide, 90 degree parking and two-way aisles are recommended. One row of 90 degree parking, plus a two-way aisle, can be installed in lots as narrow as 42 feet. The smaller the angle (45 to fiO degrees) the easier it is to park, though cars with power steering are easy to park anywhere. For 45 degree stalls, 14 foot aisles will be satisfactory for one-way traffic. For 60 degree stalls, 18 foot aisles are recommended to give suf- ficient clearance for drivers backing out of the stalls. The Eno Foundation for Highway Traffic Control suggests the following steps in laying out a parking lot. 1. Make an accurate drawing of the area including the following: - Outline and use abutting properties, buildings and vacant areas. - Abutting sidewalks, streets and alleys with direction of traffic flow on each. *Repri"n"ted with permission from The Great Lakes Fruit Growers News 23(3): 64, March, 1984. 16 - Points where access to abutting properties must be preserved. (Use of wheel stops and guard fences can protect adjoining property and buildings.) - Locations of any fixed obstacles which cannot be removed. - Setbacks required by local building ordinances or codes. - Space needs for any required or desired screening, such as fences, hedges, landscaping, etc. - Location of market and any other facility the lot is intended to serve. 2. Determine the possibilities of acquiring any small abutting property which would give access to a second street or to an alley and permit a better circulation pattern. 3. Consult local building codes and zoning ordinances for any possible instructions or requirements as to a size of curb cuts, fencing or screening, drainage, lighting, hours of operation, signs, etc. 4. Lay out the actual spaces and bays on a piece of graph paper (everything - building, lots, etc.) to scale. This method will enable you to mini- mize the use of the parking area. Approaches and driveways are very important and can add much to the appeal and safety of the market. They should be long and smooth, whenever possible, with space for at least 2 cars (40 feet) on the de-acceleration lane to give the motorist a chance to pull off the highway safely some distance from the market. The driveway into the market should be as far from intersections as possible and be clearly marked with directional arrows to start traffic in the right direction. ^ parking lot surface can be gravel, soil or paved. It is important to provide proper drainage, or pot-holes, ruts, and corduroyed surfaces will develop quickly. Drainage requirements will depend largely on the internal soil composition. Sandy or gravelly soils need very little slope to provide satisfactory surface drainage. Heavy clay soils need to be sloped very con- siderably for proper runoff, but not so steep as to cause cars to run away. Unless guided or directed, drivers do not make efficient use of the parking spaces. You can assist them by striping or marking the parking lot. More farm markets are providing shopping carts because their use increases sales. If you have an asphalt or concrete parking lot, carts can be pushed out to the cars. If the parking lot is dirt or gravel, provide a sizeable sidewalk where customers can leave their bask-carts on a hard surface while the car can be brought up to the store front for loading. Cooperative Extension Service U.S. Department of Agriculture University of Massachusetts Amherst, Massachusetts 01003 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, $300 POSTAGE AND FEES PAID U.S. DEPARTMENT OF AGRICULTURE AGR 101 Third Class Bulk Rate 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. 4 FALL ISSUES, 1985 Table of Contents Fruit Notes Subscription Orchard Mouse Control: Points to Ponder, Items to Consider Fate of Lead-Arsenate in Old Orchards Host Learning Behavior of Apple Maggot Flies Fruit Growing in Australia A Brief Summary of Rootstocks and Interstem Trees Comparison of Some Fruit Characteristics of "Mcintosh" Apples Grown on Seedling and M7 Rootstocl100ppm • >200ppm « >300ppin -k >400ppm SCALE (m) I" I ■ ■ I « 0 L2 2.4 •••• A 21 1« 17 15 13 11 9 7 S 3 1 Fig. 1 Spatial distribution of lead in ug/g (= 0.9 lbs/acre) at a site in the former orchard at the University of Massachusetts--Amherst cam- pus. Shaded areas indicate concentrations in excess of 400 uq/q (360 lbs/acre). ^ Not only was the spatial distri bution well defined, but the lead and arsenic concentrations decreased sharply with depth. Highest amounts were evident in the organic-rich surface horizons, while in the subsoil the values rapidly decreased to background levels. A subsequent study in ten old, heavily contaminated orchards revealed more or less the same patterns. The lead always was associated with the organic material in the surface layer, some orchards having values up to 4400 ug/g (4000 lbs/acre). Arsenic concentrations usually were ? to 4 times less than the lead concentration at the same point, resulting in values up to 1300 ug/g (1?00 lbs/acre''. The maximum peak of arsenic often was below the depth of highest accumulation of lead, indicating that the arsenic may have moved within the soil profile, although prohably not to any great extent. Since arsenic in its behavior is related to phosphorus, i.e. it can be removed by phosphorus applications from the exchange sites on the clay particles, it appears wise to limit applications of phosphorus-containing fertilizers in contaminated orchards to just what is needed for plant-uptake. In the survey of the ten old orchards in various parts of Massachusetts a few sites did not show any high values for either lead or arsenic. One possible explanation may be that in some orchards it was customary to let cows or other animals graze. Since the lead-arsenate material is virtually insoluble, a significant portion of the residues adhered to the grass plants and may have been removed by the grazing animals. The presence of old orchards, therefore, does not necessarily mean that one automatically has a contaminated site. The survey also indicated that soils with high clay contents tended to retain arsenic better than sandier soils. A common inquiry is, "How do I remove the lead-arsenate or at least bring it to within acceptable limits?" Stripping the entire site of surface soil is impractical, costly and often unnecessary. The best solution to this type of pollution is dilution in the form of plowing, making sure that the plow turns the soil over as much as possible. Vegetable gardening should be discouraged or limited to non-leafy produce, depending on the level of contamination. POMOLOGICAL PARAGRAPH Wil 1 iam J. Lord Lime for Scrubbing CA Storages. Occasionally growers receive lime that is not fresh and it fails to absorb adequately the carbon dioxide in the CA room. It may be completely ineffective or become ineffective after only 2 or 3 months. D'*y lime for CA rooms should be fresh, high in calcium and have a magnesium content not over 10?^. Specification for good lime for CA rooms would be "fresh hydrate with about ''^-1^1- calcum oxide and only 1-?% magne- sium oxide." If a "^0 pound bag of hydrated lime weighs more than 'i5 pounds you can be pretty sure that it is worthless for scrubbing. Another simple test to determine suitability for use in CA rooms is to place 3 tablespoons of the lime into a glass and add 3 tablespoons of water while stirring with a ther- mometer. If the temperature of the water does not increase it means that the material is probably useless. If it goes up ^-3 degrees, it is suitable. - 5 - HOST LEARNING BEHAVIOR OF APPLE MAGGOT FLIES Ronald J. Prokopy Department of Entomology During the past decade, I have written numerous articles in FRUIT NOTES about the natural history and economic importance of apple maggot flies. The more we have studied the biology of this major apple pest, the more we have become fascinated with its behavior. Here, I will describe briefly the results of some of our recent experiments that demonstrate that apple maggot flies, like humans, have an ability to learn. In Massachusetts and elsewhere, the apple maggot fly has two principal hosts: hawthorn fruit (the native host) and apple (first introduced to the United States by the Pilgrims about 1620 and first colonized by apple maggot flies about 1850). In 1981, we discovered that apple maggot flies which had been maintained in laboratory cages without fruit since emergence (and thus were naive) showed a high level of acceptance of hawthorn fruit for egg- laying and a moderate level of acceptance of apples. When we went to the same apple trees from which the pupae of these flies had been collected and then tested flies that had been laying eggs for about a week in the apples there, we discovered that the flies still showed a moderate level of accep- tance of apples but failed altogether to accept any hawthorn fruit for egglaying. This finding caused us to wonder whether the flies might be capable of learning with respect to host fruit acceptance. We then proceeded to "train" groups of flies in the lab by providing them apples for several ovipositions and then testing their responses to hawthorns. We also did the reverse: training on hawthorns and offering apples. In all tests, most flies trained on one fruit type (termed the familiar type) refused to oviposit in the other fruit type (termed the novel type). The training proved reversible. That is, flies trained on apple and rejecting hawthorn could, after three days without any fruit, be trained on hawthorn and found to reject apple. To our surprise, we recently found that flies that have had familiarity with one fruit type do not accept that fruit type to any greater degree than naive flies that have never laid an egg. Rather, the former flies simply reject a novel or unfamiliar fruit type to a greater degree than do naive flies. It turns out that flies reject novel chemical fruit stimuli (e.g., fruit having a rather different aroma) as well. as novel physical fruit stimuli (e.g., fruit of a rather different size). This appears to be the first proven case in any animal including humans that the nature of learning can be of a type in which a familiar stimulus does not become increasingly acceptable with experience but rather that a novel stimulus becomes decreasingly acceptable. How does the ability of apple maggot flies to learn to reject novel fruit stimuli affect the flies' foraging behavior for fruit in nature? Presently, we are attempting to gain a partial answer to this question through experiments we are conducting in a very large field cage that con- tains mixtures of potted apple and hawthorn trees. First, we release onto one of the trees a single female whose previous egglaying experience is _ «; known. For example, the female may have, during the previous week, laid all her eggs only in hawthorn fruit, or only in apples. Then we track by eye all the female's movements as she forages among the mixture of trees, recording every time she lands on and accepts or rejects an apple or hawthorn fruit. Our findings to date in this field cage confirm our previous laboratory findings and suggest, in general, that apple maggot flies that have ovi- posited in a given fruit species in nature i^or some time may have difficulty in switching to another fruit species readily. If this is so, then females immigrating from neighboring wild hawthorn trees into commercial apple orchards might pose less an immediate threat to the apple crop than females immigrating from neighboring abandoned apple trees. Whichever, the host- learning ability of apple maggot flies is yet another intriguing dimension of the life of this important apple pest. POMOLOGICAL PARAGRAPH Will iam J. Lord Refrigerated salesrooms. Among the reasons for shopping at roadside stands are freshness, quality and better flavor of produce. To help maintain attributes of produce sold at roadside stands, a number of growers have refrigerated their sales rooms to retard fruit deterioration. Temperatures maintained in the refrigerated salesrooms vary from 40° to SOO F during the day and from 3^"^ to ^0° F at night. The refrigerated sales areas also pro- vide excellent display space for cider and a mass display of fruit for self- service. Furthermore, one of the main reasons why Mcintosh apples are below grade at roadside stands is because of broken skin. In a study conducted years ago, we found that l^"*- of the Mcintosh apples marked U.S. Fancy at roadside stands were below grade because of cuts and stem punctures and/or decay had occurred in some instances. The installation of a refrigerated sales area appears to he a realistic approach to increased sales through product improvement and as a means of preventing fruit deterioration since small, shallow stem punctures are allowed in U.S. Utility grade apples but none with softening around the punctures. - 7 FRUIT GROWING IN AUSTRALIA Duane W. Greene Department of Plant and Soil Sciences [Editor's Note: Dr. Greene was on sabbatical leave from August, 1983, to April, 1984 at the Horticulture Research Institute, Knoxfield, Victoria, Austral ia.] Australia is a country that is areawise approximately the same size as the United States. It is located between 10 and 39 degrees South Latitude, whereas the US is located between 26 and 49 degrees North Latitude. Since it is in the southern hemisphere, its seasons are the opposite of ours. They are in the middle of summer in January. Australia is a country with 7 states, and usually produces a total of about 19 million bushels of apples. Northern Territory. The newest state, it occupies a large part of the northern portion of Australia. Being close to the equator, it is very warm and humid all year. No apples are grown there, Queensland. This is also a northern state. It is known for wheat, citrus, peanuts, a few apples and the Great Barrier Reef. The remaining states are located all or in part in the cooler southern portion of the continent. New South Wales. Five to six million bushels of apples ^re produced there, more than in any other state. The Batlow area is probably the best area in NSW, having a relatively high elevation, and it specializes in Delicious. Orange is another large, important production area. Sidney, with a popula- tion of over 3 million people, is located in NSW, so growers here are closer to the largest city in Australia. Western Aust^'al ia . This area produces Granny Smith, primarily for export. Victoria. Victoria, located south of NSW, produces about 4 million bushels of apples, but has no real production centers. Tasmania. This is the island state located south of continental Australia. Tasmania produces about 4 million bushels of apples. Historically, it has been a major production area, and is called the "Apple Isle". South Australia. This state produces about 1 million bushels, with Granny Smith as its principal variety. - 8 - Growing Conditions The climate in all apple growing areas can be described as mild by our standards. It snows ■^ery infrequently, and the severity of the season is described not in terms of ice, snow, or subzero temperatures, but by the number of frosts during the winter. In Victoria, frosts are infrequent, and the usual winter lows are above 40* F. With the exception of January and February, when temperatures can be hot, the weather can be described as cool and very comfortable. They get 20-50 inches of rain annually, coming mostly in the Fall, Winter, and Spring. The summers are usually hot, windy, and dry. The weather is extremely changeable, and hail is a major problem and constant threat. Drastic temperature changes usually accompany the hail. I experienced a 20' F drop in temperature in 10 minutes. It can rain at almost any time. Australia is a "jery old continent. Its soils are basically poor. Underlying this thin layer of soil is a rather impervious layer of clay. Therefore, most trees are grown in nounds. This provides enough soil to grow a tree, and raises the tree enough to avoid water that is trapped above the clay layer. Trees are frequently planted without digging a hole; a tree is set on top of the ground, and soil is then mounded up around the tree. Australia is a water-poor country, having few large rivers or lakes. Even though most growing areas receive 20-50 inches of rain each year, all good growers irrigate, because very little rain comes during the growing season. During the summer, temperatures are frequently high, the wind blows constantly, and the relative humidity is very low. All these factors encourage rapid evaporation. There are few rivers and streams for irrigation, and ground water is frequently salty and unsuitable for irrigation. Therefore, nearly all growers have ponds where they collect runoff water during the winter and spring. This is their main source of water. Most orchards are irrigated, primarily by trickle irrigation. Generally, the tubing is run through the lower scaffold limbs of trees, which are about ? feet off the ground. This makes care around the tree much easier, but it also makes movement across rows in an orchard very difficult. Tree Growth and Development Tree growth and development is different in Australia from what it is here. This difference can, I believe, be attributed to the climate. Because of the mild winters and relatively cool springs, flowers open slowly and over a long period of time. Bloom commonly lasts 3-4 weeks, making the timing of chemical thinning difficult. Trees in Australia do not have the same rapid flush of growth in spring that ours do. The growth rate is rather slow, but it occurs over a much longer time. Terminal shoot growth occurs throughout the whole growing season, commonly extending over a 5-5 month period. Late growth in the fall and subsequent winter injury is not a problem because of the mild climate. Because of a lack of stress during the bloom and postbloom period, fruit set is generally excessive. Unlike on trees here, fruit set in Australia can occur on very upright wood. This is a big advantage, because fruit set can occur on younger trees, and limb spreading may not be required. - 9 Northern Spy (20?o dwarfing) is the major dwarfing rootstock used. In Victoria, 70-80/i of the trees were budded on this rootstock. On poor sites it was necessary to grow trees on seedling roots to insure adequate growth. Rootstocks less vigorous than Mailing 7 have been unsuccessful because of conditions that do not favor vegetative growth. Many trees in Australia are trained to a vase shape. This method is characterized by many limbs coming from a point. In order to develop this tree, extensive and severe pruning is required for 8-10 years. Because flowering is considerably delayed, limb propping is necessary, and pruning costs are high. Growers especially in September. In at least two blocks, defoliation from WAL leaf feeding was severe, as was the amount of WAL honeydew on fruit. Growers are reminded that W^L are resistant to organophosphate insecticides (e.g., Axinphos- methyl, Phosmet), so that such m^iterials cannot be expected to provide acceptable control. Pi sease S i tuat ion. This year was quiet in comparison to the disease situation in the 1584 season. There were only two to four major apple scab infection periods during primary season, depending on the region of the state. Generally, primary ascospores were aval lable in significant amounts from April 20 to May 25, plus or minus a week, depending on region. However, rainfall luring this period was light, and when rain fell it was often too cold foi an infection period to occur. The most significant infection periods uere between May 17-19> when a large number of ascospores were available. As a result, in unsprayed trees at our Belchertown test site, we had only 11% leaf scab and k.2% fruit scab (compared to near 100? levels in other years). The cankering problem (See Fruit Notes 50(1):17-21) had decreased significantly in Massachusetts with the exception of the Granville area. Apparently, weather and Bordeaux or KocideTl applications combined to alle- viate the major diuback seen in 198'*. Roberta Spitko of New England Fruit Consultants successfully isolated Erwin ia amy lovora, the fire blight orga- nism, from oozing fruit in cankered Marshall Mcintosh trees. This is signi- ficant because it indicates that a perennial canker and dieback observed on Marshall Mcintosh for a number of years is not necessarily related to the 1984 outbreak, and is not necessarily a new apple disease. At this point, we feel the 1984 outbreak was primarily a cold-stress phenomenon, while the Marshall Mcintosh situation is probably related to fireblight. Virus-like symptoms causing rough bark on young (7 to 10 year old) trees were apparent in a few orchards. Of these orchards, all but one had 10 only a few trees showing rough bark. However, in one, an entire bIocl< of Macouns showed the problem, in which outer layers of barl< flake and scale from the tree, exposing the cambium. We tentatively have indentified the disease as blister bark, as described by Dr. Lee Parish. if so, the disease is not believed to be economically significant. Sclerotinia-caused blossom end rot continued to be a problem in a few orchards. We have yet to assess economic impact of the problem (visual estimates of up to 20^ fruit infection in June have been made). New or Unusual Outbreaks Walnut Husk Fly (Rhagolet i s suavi s [LeowJ), a relative of the Apple Maggot fly, caused substantial injury tc peaches in £ Granville block and flies were also seen on peaches in Wilbraham although no injury was found. In Granville, injury (deposition of numerous eggs at e;)ch oviposition site) was associated wi h extensive burrowing through peach flesh. Such infesta- tions are extreme y rare, although a similar situation was described in New York State in 1969 by R.W. Dean. A Fruit Notes article in a subsequent issue will provide more information on this occurrence and discuss the possibility of this event occuring again. Mealybug. Sooty mold growth in the calyx of apple; was seen at several sites, injury that New York Stete entomologists have [)reviously identified as being caused by the Comstock Mealybug (CMB). This insect is a common inhabitant of apple orchards, but is normally held below economic threshold levels by predators. Recent pesticide use patterns, including the use of pyrethroids, have been implicated in outbreaks. Tree Crickets. (Genus Oecanthus ) . Slits in one-year-old peach wood which contained numerous eggs of Tree Crickets were seen while pruning a block of peaches in Wilbraham tiis past spring. This injury occurred last summer and was readily removed djring pruning. Injury is similar to that of periodic cicada, a cyclical pest which has been increasingly evident this year in orchards in Pennsylvania. Plans for 1986. Once again, the fate of USCA IPM money is uncertain at this time, with the budget-balancing Gramm-Rudman amendment likely to result in £t^ least a 10^ across-the-boerd cut in the USDA budget, and presumably in IPM funds as well. The State Department of Food and Agriuclture IPM money will once again be available. However, this will be reduced by at least 10% because of deduction for overhead mandated by University policy. Present I986 plans call for a continued apple IPM program similar to that in I985. In addition, we hope to impirove grower calibration skills and the frequency of sprayer calibration. Beginning with the March Fruit grower meetings, IPM staff and private sector equipment dealers will present sessions on the theory and practice of calibration. At a later date, regional fruit agents will hold workshops in advance of the growing season at which actual dynamic calibration of different model sprayers will be demonstrated. We also shall attempt to evaluate the utility of releasing the predator mite Amblyseius fal laci s in orchards. This predator is being 11 - reared by a New ^lersey Dept. of Agriculture lab and may ultimately be available for purchase from private sector insectaries. Much information is needed concerning the ability of th !se lab-reared predators to survive in sprayed orchards, optimal release "ates and timing, release techniques, etc., before it will be possible to augment our biological mite control agents on a large scale. SPENCER REVISITED Wesley R, Autio Department of Plant and Soil Sciences Univeristy of Massachusetts The Spencer ajple was recommended strongly at one time for trial in Massachusetts but never gained a great deal of popularity. It is a large, high quality apple with white, crisp flesh which ripens slightly later than Baldwin, It has a red blush ove - 50 to 80 percent of the fruit surface. Spencer originated as a cross of hiclntosh and Golden Delicious made in 1929 at the Summerland Researcli Station in British Columbia. The first trial plantings were established in 19^1 and 19^*2 (1), and they found Spencer fruit to be of very high quality and to store better than Mcintosh. However, it was no; released immediately, because data from some locations suggested that it had a tendency to develop excessive breakdown and core 'lush during storace (1). It finally was named and released in 1959 at the •equest of Professor O.C. Roberts of the University of Massachusetts. The first planting in Massachusetts (1950) was on Orchard Hill at the Amherst campus of the University. Fruit from this planting were very high quality and did not experience excessive breakdown or core flush during storage. Professor Weeks considered it to be a late winter apple (2). A planting of Spencer trees was established in 196^ at the Horticultural Research Center in Belchertown, MA. Fruit from these trees develop considerable amounts of breakdown during long-term air storage in most years, but early in the storage season the fruit are very high quality for eating and cook ng. Some Massachusetts growers have had reasonable suc- cess with Spencer ii- their CA storages. Regardless of the storage potential, the high quality and nice appearance of Spencer fruit suggest that it could be an excellent apple at farm stands and roadside markets for sale in the fall. It is certainly worthy of trial . References Cited; 1. Fisher, D.V. 1959. The Spencer apple. Fruit Var. Hort. Dig. 14:15-16, 2. Weeks, W.D, I960. Performance of the Spencer apples in Massachusetts, Fruit Var. Hort. Dig. 15:l6. - 12 - GALA: A NEW CULTIVAR FOR NEW ENGLAND? Duane W. Greene and Wesley R. Autio Department of Plant & Soil Sciences Univeristy of Massachusetts Gala is a new apple cultivar that was recently introduced from New Zealand. This cultivar is being planted extensively in the United States and elsewhere in the world. The purpose of this article is to update a pre- vious report (Fruit Notes '49{2):l8. igS't) and to present preliminary infor- mation on the suitability of Gala for culture under New England conditions. Gala was introduced in New Zealand in 1962 by Dr. Donald McKenzie. It was the result of a cross between Kidd's Orange and Golden Delicious. We planted Gala/M26 in 1978 at the Horticultural Research Center. The fruit is smooth round conic with a red strip over a golden yellow ground color. We have noted no russeting tendencies similar to Golden Delicious. The flesh is firm, yellow, juicy, and more dense than other apple cultivars. The distinctive spicy flavor, the attractive color, and the firm crisp flesh make Gala an apple that is distinctive and easily identifiable. Our experience at the Horticultural Research Center confirms other reports that it is both precocious and productive. The first commercial crop was produced 3 years after planting and in the fourth year production was up to 3.3 bu/tree (Table 1). If these trees were planted at a spacing of 12/22, as we currently recommend (175 trees/ acre), the yield during this fourth year would have been over 500 bu/acre. Trees have continued to be productive so that in their 7th leaf over 8 bu/tree or 1300 bu/acre were harvested. They have shown no sign of biennial bearing. Preharvest drop has not been a problem so that the use of daminozide as a stop-drop would not be necessary. Table 1. Yield of Gala/M26 planted at the Horticultural Research Center in 1978. 1981 1982 1983 198i» 1985 Total Yield/tree (bu)* 0.^4 3-3 2.7 ^.3 8.4 19. 1 Yield/. ere (bu) 66 S'fS 4^5 710 I386 3152 *Based on 12 X 22 planting distance (l65 trees/acre) - 13 - The development of red color has be'n good (Table 2). It compares quite favorably with Mcintosh harvested on Sept. 6 (Table 3). The bright yellow ground color is attractive and contrasts well with the pink-red color. Gala was harvested at several times during September and early October. The optimum harvest, we believe, was September 17> although at least one additional harvest would have been necessary to get poorly colored fruit. Flesh firmness dropped the longer fruit were allowed to hang on the tree, but the reduction was not as great as with Mcintosh. Fruit harvested on October k were still quite firm and very crisp although fruit acid level seemed quite low. Table 2. Fruit characteristics of Gala when harvested at different times during the harvest season at the Horticultural Research Center. Fruit Harvest Date characteristics Sept. 17 Sept. 25 Oct. 4 Red color {%) 60 66 69 Soluble sol ids {%) 11. '4 121 12.2 Flesh firmness (lb) I6.5 15.1 1^.5 Weight (g) 173 178 I88 Table 3. Fruit characteristics of Mclntosh/M26 planted at the Horticultural Research Center in 1976. Fruit , Harvest date characteristic Sept. I6 Red color {%) 63 Soluble sol ids {%) 11.6 Flesh firmness ( lb) 15-8 Fruit weight (g) 160 Sept. 25 81 12, .6 1i», .0 184 - 1^ It has been suggested that the size of Gala may be small, however, the fruit harvested at the Horticultural Research Center have had good size. On September 17 fruit weight was 173 g and this corresponds to fruit that is approximately 3 inches in diameter. We have seen no tendency for fruit size to decline although our trees are still relatively young. We have followed the onset of the ethylene climacteric and find that Gala, unlike other cultivars, displayed what appeared to be a degree of ethylene insens i t ivi ty • It did not initiate the ethylene climacteric until internal ethylene levels increased to near 3 ppm whereas Mcintosh and other cultivars initiated the climacteric when ethylene levels were below 1 ppm. This could be one reason why Gala appears to store very well and not suffer from preharvest drop. We have observed some shriveling in storage similar to that observed for one of its parents, Golden Delicious. Storage in polyethylene-lined containers may be necessary to minimize shriveling. There are several red coloring sports of Gala that have been described by Dr. McKenzie. Royal Gala and Imperial Gala are scarlet red and heavily striped. Regal Gala has a solid scarlet blush. According to Dr. McKenzie Regal Gala develops the best color, however, even small amounts of shade significantly reduce the red intensity. Only those willing to prune trees for good light penetration should attempt to grow Regal Gala. Gala and its red sports are pat -nt pr:)tected. Currently, Stark Bros. Nursery, Louisiana, MO holds patent rights to Gala and Royjil Gala. Under a special licensing agreement with Statk Bro,., Van Well Nursery, Wenatchee, WA and Carlton Nursery, Parker, WA a' so se!l Gala and Roye 1 Gala. Hi'ltop Nursery, Hartford, Ml has patent rights on Regal Gala and Imperial Gala. We in New England are able to grow the best Mcintosh in the United States. Since Gala ripens at about the same time as Mcintosh or perhaps slightly earlier, we may also be the best place in the United States to grow Gala because of our coloring weather. Gala has also developed high customer acceptance. We feel that Gala is an exceptional apple that is worth planting in Massachusetts. POMOLOGICAL NOTE Jonagol d Loren D. Tukey Department of Horticulture Pennsylvania State University Jonagold is a good yieldinc, apple cultivar of excellent eating quality which is attracting much attention across Europe. The tree has strong wide crotches and is spreading. It crops mainly on spurs. It has handled and produced well on the Dutch slender spindle training system with M9. Yields of over 1000 boxes/acre ('♦2 lb units) have been reported. Because of its 15 vigor (triploid), Jonagold can be grown on M27, especially on vigorous apple soils, but fruits are slightly small in size. The cultivar was introduced in 1968 by the N.Y. State Agr. Exp. Station in Geneva, and is a cross of Golden Delicious and Jonathan. The fruit is golden-yellow in color with red striping or a solid blush, under good sunlight conditions. Improved red color clones have been reported from Japan and England. Jonagold is similar to Jonathan in flavor, ripens with Golden Delicious, has a long storage life, and has excellent processing quality. The cultivar should do well in Pennsylvania, based on trials at Rock Springs. (Reprinted from Penn. State Horticultural News, Vol. 3'4 , No. h.) POMOLOGICAL NOTE Apple Cultivars in West Germany Loren D. Tukey Department of Horticulture Pennsylvania State University Preference for certain apple cultivars in West Germany was shown in a survey made by the Wonnegau Fruit Growing Society at a fruit exhibition in Worms. The event was held to introduce newer apple cultivars and to promote those baing grown in the Wonnegau area. Visitors were given a choice of 11 apple cultivars to purchase, and were encouraged to try one unknown to them. Sales and comments were tabulated. Those in the well-known group were Geheimrat Oldenburg, Red Boskoop, Cox Orange, Gold Parmane and Golden Delicious. The newer cultivars consisted of Jonagold, Gloster, Mutsu, Idared, Melrose and Granny Smith. Jonagold was the most popular, accounting for 25% of sales, and tasters asked where they could be purchased. Next in sales was Cox's Orange (15^), followed by Idared (12)^ and Melrose (10^). In terms of price, sales were affected only slightly. Red apples were pre- ferred to green/yellow ones. The lack of general appeal for Granny Smith (3^) was attributed to the age of the buyer. Based on the survey, this cultivar is "of the young people", roughly 25 years old and under, and was liked especially by girls and young ladies, according to G. Steinborn, State Teaching and Research Institute at Oppenheim. (Reprinted from Penn. State Horticultural News, Vol. 3^, No. '♦.) 16 RECOMMENDED PEAR CULTIVARS FOR THE NORTHEAST Francis C. Del lamano Cooperative Extension Association of Oswego County Mexico, New York To make a profit when growing pears it is necessary to produce high yields (500 + bu/acre) of large fruit (preferably greater than 2 1/2 inches in diameter bit 2 3/8 inches at a minimum). Unfortunately, nearly 10 years is usually required to obtain .3 profitable crop, but the use of dwarfing rootstocks an good cultural practices can reduce this period to 7 years. The following are brief descriptions of the pear cultivars which can be grown profitably in the Northeast. BARTLETT is the most widely planted and best known variety for Fresh con- sumption and canning. Adequate, early pollination and good cultural prac- tices are necessary to obtain good yield and size. If the trees are in good vigor they may not respond well to thinning with NAA. If harvested at l8 to 21 lbs firmness and cooled quickly, fruit will store well. By delaying har- vest a week and beginning to pick at 16 lbs., size and yield will be increased by at least 10^; howev;r, shelf life will be reduced. BOSC is a good variety which is increasing in importance, because increased knowledge of Bosc culture has resulted in the ability to produce fruit 2 1/2 inches and larger. Generally, t:he Northeast can produce high quality Bosc fruit with prices varying from 30 to 100? higher than Bartletts. If you are purchasing Bosc trees, select only those which are virus-free. Because of sensitivity to cold winter temperatures (southwest trunk injury) trunks should be painted with white latex paint. Good fertility must be main- tained, particularly for potassium, because Bosc trees are sensitive to low potassium levels. Thinning is accomplished easily with NAA, and hand thinning is seldom needed. Fruit should be harvested at approximately the same time as Mcintosh apples. \ields can exceed those of Bartlett by 2S+%- (Note: Bosc is not the best pollinator for Bartlett, since it blooms during the last half of Bartlett bloom in most years.) CLAPP pears are harvested 2 to 3 weeks prior to Bartletts, and it is a good variety for its season. The tree is winter hardy, productive, and a good pollinator. Fruit which are 2 1/2 inches or larger are obtained easily with adequate thinning. Fire blight is a problem with Clapp trees, and the fruit decays internally prior to softening. SECKEL is a small, sweet pear harvested just prior to Mcintosh apples. Because of low prices from 1950 to 1975 pear growers moved away from Seckel, but the demand presently exceeds the supply and now the prices are good. Thinning chemicals do not work on Seckel, so it is difficult to produce fruit larger than 1 3/k inches. SPARTLETT trees produce fruit which are 50% larger than Bartletts. They can develop a red cheek and have a nice appearance but are not as high quality as Bartlett. The trees have poor crotch angles and weak wood which can break with a crop load. Fruit set is generally poor but can be improved with daminozide (Alar^), - 17 - FLEMISH BEAUTY pears are large and sweet with a red cheek. They are har- vested about 1 week after Bartletts. Trees are vigorous, very winter hardy, and must be thinned with NAA to get adequate size. Flemish Beauty is an old variety which lost popularity because of susceptibility to pear scab and may be difficult to sell because it is unknown. Only trees free of stoney pit virus should be planted. (Note: Flemish Beauty is an excellent pollinator for Bartlett. ) ANJOU is a large, green, winter pear which is harvested in early October. Trees are late comirg into bearing but are quite productive. Chemical thinning is necessary to obtain adequate fruit size. Spring frosts can harm fruit finish, and Captan sprays can burn the leaves. Fruit must be stored after harvest to initiate the development of good flavor and ripening. AURORA was introduced by the New York Agricultural Experiment Station in Geneva. It is harvested near the end of Bartlett harvest and is a good quality pear for the roadside market. Chemical thinning is necessary for the development of adequate size. HIGHLAND is another introduction from the New York AgricultJral Experiment Station, Geneva. It is a russeted pear which resembles Bosc. JUNO (Butirra Precoce de Morettini) was introduced from Italy and is similar to Barlett in shape but is harvested 3 weeks earlier. I was impressed with its quality in California and at the Agricultural Experiment Station in Geneva. Fruit are large with good flavor, and the trees appear to be pro- ductive. More will be known about this variety in the next few years. RED PEARS are bringing big money in West Coast wholesale markets and Eastern retail markets. Many trees are being planted in the West. Is the demand sufficient to handle a lot of new plantings? Only time with tell. Generally, red varieties are less vigorous and productive than their green relat i ves. PEACH CULTIVARS FOR NEW JERSEY WITH POSSIBLE ADAPTATION TO NEW ENGLAND STATES Jerome L. Frecon Glouster County Agricultural Agent Cooperative Extension Service Cook College - Rutgers University The 1982 Fruit Tree Census for New Jersey lists Rio Oso Gem, Loring, Redhaven, Cresthaven and Jerseyqueen cultivars in order of importance in the state's fruit industry. Tree varietal trends will not change drastically in the immediate future. Each cultivar has weaknesses and strengths. Rio Osa Gem is large, generally attractive, firm, yellow-fleshed, freestone, and most importantly, it matures late (September 1 to 10). The tree is weak. 18 - crops erratically, and produces a significant percentage of fruit with a rough, raised suture. The fruit and foliage are susceptible to bacterial spot, a problem on trees grown in our South Jersey sandy soils. Loring and Jerseyqueen are both large, attractive, firm, yellow-fleshed peaches. Both are strong vigorous trees. Jerseyqueen i: susceptible to bacterial spot and matures late (August 2h to September }) . Loring is tolerant to bacterial spot and matures mid season (August 10 to 20). Both cultivars crop unreliably because of the fluctuating temperatures we experience in mid winter and early spring. Cresthaven is a near-perfect peach. jf thinned early, it will attain excellent size. The fruit have short stem^ and a round shape, making it occasionally prone to softening and injury around the stem. The tree is an excellent cropper but somewhat weak and shor lived. Most fruit growers are familiar with Redhaven. It has the strengths and weaknesses in Ne / Jersey that it has in New England. same Now that you know what wf grow and tolerate in New Jersey, you can see we need much improvement in )ur peach cultivars. Thousands of cultivars have been field-tested in New Jersey in the past 200 years. Sixty cultivars have been introduced by the New Jersey Agricultural Experiment Station since the establishment of its peach breeding program in 191^. Our primary objec- tive today is to develop and evaluate large, high quality, attractive, later maturing, new, firm, yellow-fleshed peach cultivars. Tree vigor, and most importantly winter hardiness, and bacterial spot resistance, are primary objectives. Encore"^ (NJ260 cultivar) is a late maturing cultivar (September 1 to 10) which best exemplifies these standards. Jerseydown (NJ2^6 culti- var) and Jerseyglo (NJ2^^ cultivar) are other recent selections with outstanding characteristics. The following yellow fleshed cultivars are recommended to New Jersey growers as the best available in their respective seasons of maturity. SEASON OF MATURITY CULTIVAR July 1 to 10 July 10 to 20 CANDOR GARNET BEAUTY, EARLIGLo"^ (Roxborough Cultivar), EARL I REDHAVEN July 20 to 25 July 2": to August 5 August 1 to August 10 August 10 to August 20 August 20 to August 27 JERSEYDAWN, HARBELLE REDHAVEN, HARKEN, HARBRITE, LATE SUNHAVEN (Slaybaugh Special cultivar) NEWHAVEN, NORMAN LORING, REDKIST BLAKE, BISCOE, CRESTHAVEN - 19 - August Ik to September 3 September 1 to September 10 JERSEYQUEEN, JERSEYGLO encore"^ (NJ260 cultivar), AUTUMNGLO, RIO OSO GEM I would plant Late Sunhaven, Loring, Blake, and Jerseyqueen with caution in most New England states because they do not crop reliably in New Jersey. Encore" (NJ260 cultivar), Auturrnglo and Rio Oso Gem may mature too late in most New England states. We have tested over 300 cultivars in the past 10 years and currently have 110 under test in replicated field plots. The following cultivars are suggested for commerical planting but are not placed on the recommended list either be ause they have not been tested long enough or have some weal m, 19, October 5, 9, and 14, respectively. The actual dates of optimum harvest would vary from orchard to orchard, but the relative times should be simi lar. 21 - NECTARINE CULTIVARS FOR NEW JERSEY AND THEIR ADAPTATION TO NEW ENGLAND STATES Jerome L. Frecon Gloucester County Agricultural Agent Cooperative Extension Service Cook College - Rutgers University Nectarines are fuzzless peaches. Commercially adapted cultivars are genetically similar to peach cultivars except for their lack of pubescence (fuzz). There are good and poor cultivars of both nectarines and peaches. Nectarines may be more difficult to grow for some because of their lack of fuzz. The control of brown rot, and the elimination of insect stings, and avoidance of mechanical injury are more difficult and generally more costly than for peaches. Nectarines may be more difficult to market because: (1) the California tree iruit industry has brainwashed retailers and brokers into believing they are unique and can only be grown in California; (2) growers on the East Coast have been growing inferior culti- vars for years and equate these with all nectarines; (3) no outlets are available for second grade fruit; {h) growers pick the fruit before it is mature which has hurt the establishment of new markets. Nectarines have promise for E.istern markets because: (l) they do not have fuzz and some consumers will not buy peaches because of it; (2) they are more attractive than peaches because the best cultivars have solid scarlet-red overcolor and high gloss; (3) the California tree fruit industry has established good markets for nectarines which are open to Eastern culti- vars that will have more red color, more maturity, and better flavor; (4) these nectarines can be distributed in Eastern markets at a lower distribu- tion cost. The following list of cultivars are recommended for areas that can grow Redhaven, Loring, and Cresthaven peaches, three of our top cultivars in New Jersey . SUMMER BEAUT: Firm me 1 1 i ng--ye 1 low flesh, freestone, SS% to 90^ scarlet red skin color, medium-large size (2 1/2" to 2 3/'*")- Ovate, good quality, very attractive, susceptible to brown rot. The tree is a reliable cropper (slightly less than Redhaven), semi-vigorous, and susceptible to bacterial spot. Ripens in early August {k weeks ahead of Elberta). SUNGLO: Firm mel t ing--yel low flesh, freestone, 75% to 80% orange to scarlet red skin color, medium-large size (2 1/2" up). Globose to ovate, very good quality, very attractive, but susceptible to brown rot. The tree is a reliable cropper (but less than Redhaven), semi-vigorous, and susceptible to bacterial spot. Ripens in mid-August (3 weeks ahead of Elberta). FLAVORTOP: Firm mel t ing--yel low flesh, freestone, 80? to 90% scarlet red skin color, medium-large size (2 1/2" up). Globose to ovate, very good quality, very attractive, but susceptible to brown rot. The tree is not a reliable cropper (equal to Loring) is vigorous and suscpetible to bacterial spot. Ripens in mid-August (2 weeks ahead of Elberta). REDGOLD: Firm mel t ing--yel low flesh, freestone, 80% to 90% scarlet red skin color, medium-large size (2 1/2" and up). Globose to ovate, good quality, very attractive, susceptible to brown rot. The tree is a reliable cropper - 22 (slightly less than Redhaven) vigorous, and very susceptible to bacterial spot. Ripens in late August (1 week ahead of Elberta). The following nectarines are suggested for trial planting in areas that can grow Redhaven, Loring, and Cresthaven, three of our top cultivars in New Jersey. FANTASIA: Firm mel t ing--yel low flesh, freestone, 80^ scarlet red skin color, large size (2 3/^" up). Globose to ovate, good quality, very attrac- tive, susceptible to brown rot. The tree is a reliable cropper (slightly less than Redhaven), vigorous, and very susceptible to bacterial spot. Ripens in late August (1 week ahead of Elberta). CRIMSON GOLD: Firm mel t ing--yel low flesh, semi-freestone, 90^ crimson red skin color. Small to medium size (2" to 2 1/^4") . Globose, good quality, attractive, and susceptible to brown rot. The tree is a reliable cropper (slightly less than Redhaven), vigorous, and susceptible to bacterial spot. Ripens in early to mid-July (6 weeks ahead of Elberta). JUNEGLO: Firm mel t ing--yel low flesh, semi-freestone, 30% scarlet red skin color, small to medium size (2" to 2 I/**")/ Globose, v( ry good quality, very attractive, and susceptible to brown rot. The trie is a reliable cropper (slightly less than Redhaven), vigorous, and su'ceptible to bac- terial spot. Ripens in mid-July (6 weeks ahead of Elberta). Similar to Crimson Gold. HARKO: Semi-firm melting — yellow flesh, semi-freestone, 80% to 30% scarlet red skin color, small to medium size (2" to 2 1/^"). Globose, good quality, attractive, and tolerant to brown rot. The tree is a reliable cropper, and is susceptible to bacterial spot. Ripens late July (5 weeks ahead of Elberta). Not as attractive or firm as Crimson Gold or Juneglo. EARLIBLAZE: Semi-firm mel t ing--yel low flesh, freestone, 8S% to 95% scarlet red skin color, medium size (2 1/'*" to 2 1/2"). Globose, excellent quality, very attractive, and susceptible to bacterial spot and brown rot. The tree is an erratic cropper. Ripens in early August {k weeks ahead of Elberta). Not as firm as Crimson Gold or Juneglo. HARDIRFD: Semi-firm mel t ing--yel low flesh, freestone, 70% to 80% crimson to scarlel red skin color, medium size (2 1/8" to 2 1/4"). Globose, very good qualit\, attractive, and tolerant to brown rot. The tree is a reliable cropper, (equivalent to or better than Redhaven), very vigorous, and tolerart to bacterial spot. Ripens in early August Ct weeks ahead of Elbertc). Not as firm as Red Diamond or Summer Beaut. RED Diy,MOND: Firm mel t ing--yel low flesh, freestone, 100% scarlet red skin color, medium large size (2 1/2" to 2 3/4") • Globose to ovate, excellent quality, very attractive, and susceptible to brown rot. Very similar in appearance to Moon Grand. The tree needs to be tested further to determine cropping capability. It is susceptible to bacterial spot. Ripens ir early August {k weeks ahead of Elberta). FAIRLANE: Fi rm-mel t ing--yel low flesh, freestone, 70% to 80% crinson to scarlet red skin color, large size (2 1/2" to 2 3/4"). Ovate, good qaality, slightly astringent, moderately attractive, and susceptible to brown rot and bacterial spot. The tree is an erratic cropper. Ripens in early to mid- September (2 weeks after Elberta). Not as much color as earlier cultivars and probably too late for New England. 23 RED RASPBERRY CULTIVARS FOR NEW ENGLAND David T. Handley Extension Vegetable and Small Fruit Specialist University of Maine Red raspberry production is currently increasing in New England, pri- marily for the retail and "picl<-your-own" markets. There are however, severe limits regarding the number of cultivars which can characteristically withstand the extreme winter temperatures, and produce a good crop during the relatively short growing season. Only those cultivars described as hardy or very hardy should be considered for the Northeast. Careful atten- tion to site selection and cultural practices can further reduce winter damage. Plant several cultivars to provide variety and stretch out the harvest season. If planting everbearing types (those which bear twice in one season), note the average harvest date of the second crop. Cultivars such as Heritage may bear too late for some areas and succumb to frost. The table below describes cultivars generally acceptable for the New England region. This is no guarantee that any of these cultivars could sur- vive every winter, however. It is more than likely that some winter damage will be experienced every year. Select cultivars according to hardiness, ripening time, and fruit quality. Always evaluate new cultivars in small test plantings for several seasons, as performance can vary according to site, soil type, and production practices. RED RASPBERRY CULTIVARS RECOffCNDED FOR TRIAL IN NEW ENGLAND OBSERVED AND/OR DOCUMENTED CULTIVAR CHARACTERISTICS Winter Sucker Harvest Fruit Drupelet Cultivar hardiness growth Thorns vason size cohesion Flavor SUrtCR BEARING Latham V. hardy Vigorous Few Mid. -late Large Cruifcly Fair Taylor Hardy Vigorous Moderate Late Large Good Excel lent Newburgh Hardy Moderate Moderate Midseason Large Fair Fair Hilton Hardy Vigorous Moderate Midseason V. Large Excel lent Good Madawaska Hard/ Moderate Moderate Early fted. large Cruibly Fair Bo/ne V. hardy Vigorous Man/ Early Mediim Good Good Nwa V. hardy Vigorous Few Midseason Mediun Good Good Festival V. hardy Moderate Few Mi dseason Mediun Good Good Prestige V. hard/ Low Moderate Early Large Crunrbly Fair Reveille V. hardy Vigorous Moderate Early Large Good r C 4-> U i) oc: o in o o — (U > UJ O 0 00 o^ *— • ^-^ E E 3 0 0 s_^ t- crv .— 0) 1 — 0 in CD C3 0 0 c C UA 0 -a AJ -12: in c 0 c u i-* •3 (U 3 + n3 + X u \- u — O) Q. l_ Q. a. < a. 0 0 Q _l 0 0 0 (1) > 11 LA UJ X c 0) c TO o c TO E TO 01 X X (1) 2 O o c c E 3 "o o TO c X 1/1 c TO - ^4 - Table 2. Effects of corrective dormant pruning (COP), scoring, and Alar" on fruit size and yield of vigorous Red Prince Del ic ious/MMl 06. Fruit weight (g) Yield (kg/tree) Treatment IsW 1979 1980 1978 1979 TpO Light dormant pruning l88ab^ 192b l80a 80a l66a l66ab Corrective dormant 206a 212a l85a 8'4a 76c 156b pruning (CDP) CDP + 1500 ppm 178b ^'♦c l63b 92a 100b lAOb dam inoz ide CDP + scoring 200a l89bc l6lb 100a 13'*a l86a ^Means within a column not followed by the same letter are significantly different at the 5^ level. Another 3-year experiment was initiated in a block of 6-year-old Cort1and/M7 trees that had not yet filled their allotted space. These trees were scored once 2 weeks after bloom in 1978 and nothing else was done the 2 subsequent years. Scoring reduced trunk circumference increase all three years and terminal growth the first two years (Table 3). Undoubtedly, one of the reasons why scoring so effectively restricted growth on these Cortland trees was that they were smaller than the Delicious, and reserve food storage in the roots was limiting. Table 3. Effects of scoring on terminal growth and trunk circumference increase on Cortland/M7 apples scored only in 1978. Terminal 1 grow th (cm) Trunk 1978 ci rcum. increas 1979 e (cm) Treatment 1978 1979 1980 1980 Control Score 33a2 28b 29a l8b 32a 28b 3.9a 2,0b '4.2a 2.8b 3.9a 3.1b ^Means within a column not followed by the same letter are significantly different at the S% level. These experiments illustrate that scoring is an effective method for controlling growth in vigorous trees. It not only controlled growth but also increased flowering and cropping on heavily-pruned trees, thus con- verting unproductive vegetative growth into fruitful wood during the time the trees were being maintained in their allotted space. Scoring is a tech- nique that you should consider if it was necessary to prune certain blocks this past winter more heavily than they should have been pruned. ***** POMOLOGICAL PARAGRAPHS Wi I I iam J . Lord Department of Plant and Soil Sciences University of Massachusetts Chemical Control of Vetch. Paraquat pi us simazine is the most commonly used herbicide combination in Massachusetts. One of the "escape" weeds from continuous use of this combination is common vetch, an alternate host of plant bug, a very troublesome insect under our conditions. Studies in Ontario indicate that terbacil rather than simazine would be the better choice in orchards where common vetch is a problem. Determining the need to thin. Probably the most dependable means of determining the need for chemical thinning of Mcintosh 10 to 1^ days after bloom is by calculating the number of fruits set per TOO blossoming clusters by actual count on several trees. This means that the number of blossom clusters on at least 2 limbs of 5 to 6 trees must be counted and recorded in each block. The number of fruits developing on the same limbs must be determined 10 to 1^ days after petal fall. If one finds (by dividing the number of apples by the number of blossom clusters) an average set in excess of 50 to 60 fruits per 100 blossoming clusters on trees that have a reason- ably heavy bloom, some thinning of Mcintosh may be necessary. A final set of 25 to 35 fruits per 100 blossoming clusters seems to be about right for heavy to moderate blooming Mcintosh. If 50 or less fruits are left 10 to ^^ days after petal fall, one may expect reductions in set during the June drop period to be sufficient so that chemical thinning will not be necessary. When in doubt, omit the spray or use NAAm at 25 ppm or carbaryl . We have never seen these materials seriously overthin Mcintosh. ***** - 6 SYNTHETIC PYRETHROIDS: BENEFITS VERSUS BIOLOGICAL COSTS IN FRUIT MANAGEMENT Ronald J. Prokopy and William M. Col i Department of Entomology University of Masachusetts and Glenn E. Morin and Robin Spitko New England Fruit Consultants Synthetic pyrethorids (SP's) were first registered for use against insects in commercial apple orchards in I983. SP's include such materials as Pydrin" ( fenval erate) , Ambush^ or Pounce^ (permethr i n, ) and Pay-Off ( f 1 ucythr inate) . We now have 3 years of experience with commercial use of SP's in Massachusetts. Here, we outline what we feel are some of the poten- tial benefits of using SP's for pest control and some of the biological costs that call into question the value of using SP's. Benef i ts. Per ounce of active ingredient, SP's are far less toxic to humans than any other class of insecticides currently used in orchards. Moreover, the recommended dosage of active SP ingredient per acre is much less than that for other sorts of insecticides. Together, these 2 facts argue in favor of SP's as potentially being of real positive value in an orchard spray program. The primary use of SP's on apples has been as a single pre-bloom appli- cation against tarnished plant bug and leafminer adults. In some orchards, SP's have also been used at petal fall against plant bug and leafminer adults as well as against plum curcu! io and green fruitworm. How effective have SP's been against their primary targets, plant bugs and leafminers? A compilation of results of tests conducted in Massachusetts, New York, and Maine from 198l to 1985 shows that single application of SP at the optimum time (tight cluster to early pink) usually reduces plant bug injury to fruit by about 70%. A similarly timed spray of Guthion" or Imidan" usually reduces plant bug injury by about 50%. Several exceptions to this general pattern have occurred, however, resulting in only 20-30% reductions in plant bug injury through SP application. These tests have also shown that a tight cluster or early pink spray of SP usually pro- vides season-long control of leafminer adults. Again, however, there have been exceptions, particularly where leafminer adult emergence has occurred over a prolonged period, beyond the duration of SP effectiveness. In sum, a single, properly timed pre-bloom application of SP offers a method safe to humans for achieving reasonable season-long control of both plant bugs and leafminers in many situations, though effective control is not guaranteed. There is no other single type of material that is as effec- tive against both plant bugs and leafminers as a SP. - 7 - 3 iol og ical Costs. There exist numerous reports in the literature that season-long use of SP's results in large buildups of spider mites on apples. Does even a single pre-bloom application of SP have any effect on mite popu- lations? To help answer this question, in 1985 we collected data in 3^* Massachusetts orchards, some of which had never used a SP and others of which used a single pre-bloom SP (usually Pounce^) for 1 or 2 years. All the orchards had used a pre-bloom oil spray. No. of No. of dosage equivalents- SP h i story orchards of miticide used in 1985 None used 9 1 .20 1 year (198^4 or 1985) 12 2.03 2 years (I98A, I985) ^ 3.l8 2 years (1983, 1984) 7 2.71 *One dosage equivalent equals actual amount of pesticide used divided by the amount currently recommended in the Pest Control Guide. Generally, miti- cide was applied only when mites reached moderate population levels (5 or more per leaf ) . These data indicate that, compared with orchards where a SP had never been used, 70^ more miticide was applied in orchards where SP's were used once (198^ or 1985), 166? more miticide where SP's were used both in 1984 and 1985, and 126^ more miticide where SP's were used in 1983 and 1934 but not in 1985. Data of this sort are merely non-experimental, correlation- type data. They cannot be taken to imply that SP usage caused mite buildup without additional data from actual experiments. Very recently, Bostonian and Belanger (1) published a series of tests where they made a single petal Fall application (recommended field rate) of several types of SP's to apple trees in Quebec and measured the actual amount of SP remaining after several weeks as well as the residual toxicity to Amb 1 yse i us fa 1 lac i s, the major predator of spider mites in Massachusetts and Quebec. Bostonian and Belanger found that 6 weeks after the single treatment at pink, \2% of the original amount of permethrin and 1 8^ of the original amount of fenvalerate still remained on the foliage. When they confined A. fallacis predators on such foliage (6 weeks after treatment), 62% of the predators on permethrin leaves and 85% of those on fenvalerate leaves died after 1 day, while only 6% of predators on unsprayed leaves di ed. These findings of Bostonian and Belanger on the very long residual life of SP's and the very high toxicity to mite predators probably constitute, in our opinion, strong experimental evidence that SP application was the cause of greater miticide use in 1985 in orchards in Massachusetts that had used SP's for one or more years. The effects of SP's on A. fa 1 laci s in orchards are probably even more devastating than Bostonian and Belanger's data reveal. On several occasions we have measured spray droplet distribution on apple tree foliage and on the ground cover beneath trees. At pink, massive numbers of spray droplets from - 8 a mist blower (1x or 6x) accumulate on the ground cover beneath sprayed trees. That is precisely the place where A^ fa 1 lac i s begins to move up into the trees. It seems almost certain, therefore, that the initial high toxi- city of SP ' s to A^ fal lac i s in the ground cover and the tree foliage poses an insurmountable barrier to effective predator suppression of spider mites. Besides the devastating effects of SP ' s on mite predators, SP's may promote apple pest buildup yet in other ways. For example, Frank Hall in Ohio (pers. commun.) has found that SP's stimulate spider mite dispersal, leading to colonization of trees that were previously free of mites. Also, data from Weires in New York (pers. commun.) implicate use of SP's in the buildup of woolly apple aphids, rosy apple aphids, and mealybugs. In addi- tion, several researchers believe (though there is no proof) that SP's biochemically alter the physiology of the apple tree in a way that pranotes greater and more rapid spider mite reproduction. We must also recognize that the more often spider mite populations rise above damaging levels, the more miticide is necessary to control them, and hence the more rapidly mite resistance to miticides will develop. The end result is an upward spiral of the cost of mite control over the long term. Finally, recent data from Ontario (McKay, pers. commun.) confirm that leafminer adults develop at least partial resistance to SP's after only 1 SP application per year for 5 consecutive years. This very rapid rate of resistance development may be due in large part to pre-adapta t ion on the part of leafminers to detoxify SP's. It turns out that SP's are detoxi'^ied primarily in the same way as DDT and its relatives. Extensive exposure of leafminers and other pests to ODT-like materials in apple orchards in the 1950's and 1960's may very well have given such pests a big head-start in ability to rapidly detoxify SP's. The more frequent the application of SP's in any one year, and the more consecutive years they are used, the greater the likelihood of rapid resistance development, as in Ontario. Cone 1 us ion. We have tried to present the evidence in favor of, as well as against, the use of SP's for pre-bloom control of plant bugs and leaf- miners. We hope each grower will weigh the evidence and make a decision that best fits his overall operation. In our opinion, use of SP's pre-bloom against plant bugs and leafminers can save money in the short run, but is very likely to be more costly (in terms of greater need for miticides and aphicides) in the long run. Under no cirumstances do we believe it advi- sable to use SP's after bloom. Such use would only promote more rapid development of leaf miner resistance and cause additional harm to mite and aphid predators. Reference 1. Bostonian, N.J. and A. Belanger. 1985. The toxicity of three pyrethroids to Amblysei us fa 1 lac i s. Agricul. Ecosyst. Environ. T4:2'43-250. ***** - 9 - IS CHEMICAL PEACH THINNING ON THE HORIZON? Wes 1 ey R. Aut io Department of Plant & Soil Sciences University of Massachusetts To obtain fruit of adequate size and quality peaches must be thinned. Presently, most thinning is done by hand or by knocking fruit off with sticks, rubber hoses, or bats. Because of the labor intensive nature of this operation much research has been devoted to finding chemicals which when sprayed on the tree can thin peach fruit. Several compounds have been tested and found to have undesirable properties, but recent work in Virginia has given some promising results. A study in I98A by Byers, et al. (1) showed that reduction of photo- synthesis of peach trees approximately at the time of "June drop" thinned young fruit. They, first of all, showed this effect with simple shading, but they also demonstrated a similar effect with a photosyn thes i s- i nh i b i t i ng chemical, terbacil (Sinbar^). A second study (2) compared several other photosynthes i s- i nhi b i t i ng chemicals and found that terbacil was the only one which had potential as a peach fruit thinner. The results of the second study (2) showing the effect of terbacil on peach trees is presented in Table 1. These were 20- to 25-year-old 'Madison' trees, and treatments were applied about 1 month after bloom. The 1000 ppm terbacil treatment removed about 1S% of the fruit and resulted in Table 1. The effect of terbacil treatments on peach thinning (from 2). Number of fruit per limb Fruit size Treatment Pretreatment Post treatment at harvest Untreated 95 a^ 76 a 2.03 c Hand-thinned 2.21 a 1000 ppm terbacil 86 a 23 b 2.21 a 2000 ppm terbacil 68 a 16 b l.\k b ^Means within a column not followed by the same letter are significantly different at the 5% level. fruit of comparable size to the hand-thinned treatment. These treatments did not damage fruit, but some leaf damage did occur. The authors indicated that the levels used in this study were too high, and less than 500 ppm ter- bacil likely would be effective. 10 - In an experiment with Cresthaven peaches (1) fruit quality at harvest was assessed after a 1000 ppm terbacil treatment and compared to nonthinned and hand-thinned treatments. Table 2 shows these data. The only signifi- Table 2. The effect of terbacil on fruit quality (from l). Soluble Red Ground F i rmnes'S sol ids color color Treatment (lb) {%) i%) (0 - 5) Untreated 66 a^ 7.8 b 63 a 3.7 a Hand-th i nned hh a 10.3 a 65 a A. 3 a 1000 ppm terbaci 1 80 a 10.9 a 61 a 3. A a ^Means within a column not followed by the same letter are significantly different at the S% level. cant differences were for soluble solids, where hand-thinned and terbaci 1- treated fruit had more total soluble solids than nontreated fruit. The results From these studies are very preliminary, and much more research needs to be done before these treatments can be recommended. However, it does appear that there is some possibility that chemical thinning of peaches is feasible. References Byers, R.E., C.G. Lyons, Jr., T.B. Del Valle, J. A. Barden, and R.W. Young. I98A. Peach fruit abscission by shading and photosynthet ic inhibition. HortScience 19:6^9-651. Del Valle, T.B.G., J. A. Barden, and R.E. Byers. I985. Thinning of peaches by temporary inhibition of photosynthesis with terbacil. J. Amer. Soc. Hort. Sci. 110:804-807. ***** 1 1 A TELEPHONE SURVEY OF EXTENSION IPM PROGRAM IMPACTS ON COMMERCIAL APPLE GROWERS IN MASSACHUSETTS Kathleen Leahy, Wiilliam M. Col i , and Ronald J. Prokopy Department of Entomology University of Massachusetts History and Development of the Survey in 198^, USDA, as part of an ongoing process of program evaluation, chose the Virginia Polytechnic Institute and State University (VPl) to design and help states administer a national IPM program impact survey. Several important agricultural commodities were chosen, including cotton, peanuts, and apples, among others. Although Massachusetts was not chosen to be a participant in the study. Dr. Edwin Rajotte and later Dr. Richard Kazmierczak, survey project leaders at VPl, indicated a willingness to supply non-par t i: i pa t i ng states with the appropriate professionally-designed survey instrument, as well as lielp in sample selection and with later analy- sis of data . Consequently, we received a draft questionnaire which was intended to be given to apple growers in New York State, a particpant in the national study. After review by several tree fruit specialists at the University of Massachusetts, a draft which was more appropriate to our conditions was developed and approved by VPl. Methods and Materials Our sample of Massachusetts apple growers was obtained from a list com- piled by the 3 regional fruit extension agents, and included most or all of the larger operations in the state, and gave adequate representation from smaller ones as well. An extensive sample was needed so that we could accurately represent the total apple-growing population. Although the ori- ginal ragional agent tree fruit mailing lists contained over 200 names, a number of the growers said they were "too small" to be included, leading to a revised estimate of 176 growers with 3 acres or more in the state. We drew a random sample from tiie list of Massachusetts apple growers arranged in Zip-Code order. This was designed to l) eliminate bias in the sample and 2) allow us to break the list down into the three major fruit- growing regions of the state. These randomly selected growers received letters informing them of the survey and its purpose and requesting their par t Ic i pat ion . Interviews were conducted on the telephone and lasted about one half hour eacli on an average, slightly more than had been expected. Growers often had a great many comments to make about the questionnaire or the program. An effort was made to record these comments in addition to survey responses, which we coded directly onto Opscan forms during the interview. In all, 88 growers answered the survey--half of our estimate of the total number of growers in Massachusetts with 3 acres or more, and a number which - 12 is sufficient for a statistical analysis to be accurate. The Opscan forms were read at VP I and sent back to us on computer tape. Statistical analyses were done on the University Cyber 175 using SPSS (Statistical Package for the Social Sciences). The data presented here represent a first-level anal ys i s--that is, no attempt has been made to correlate data (e.g., pesti- cide use vs IPM adoption). We hope to present a further analysis in a future article. Grower Demographics Respondents ranged in age from 18 to over 80. The median age group was '40-i»9, with a fairly normal d i s t r i but ion--that is, there were no big jumps or dips in size among the population groups. Thirty-eight percent of respondents were over 50, which perhaps reflects the fact that farmers don't retire at age 65- A large proportion (32?) of the respondents said they had been farming for over 30 years. Quite a few growers wanted to give the same response to "age" and "number of years farming." Ninety-three percent of the respondents were male. The majority of apple growers in the state are college-educated. Over 50'^ had finished college or done post-graduate work. Seventy-nine percent had at least attended college. Orchard Size Orchards ranged approximately from 3 to 300 acres. (There was no lower limit set as such, but growers with less than 3 acres tended to feel that the survey questions addressed issues that were not relevant to them.) The median orchard size was in the 21-^40 acre range. Seventy percent of respon- dents fell in the same ranges for "acres farmed" and "acres of apples farmed," indicating that most apple growers are not diversified but tend to concentrate on one crop. Over 50? of growers earned more than 25? of their income on the farm-- h3% earned over 75?. The correlation between orchard size and percent income was rather scattered, but most growers with more than 20 acres were getting most of their income from the farm. Fifty-one percent have size-controlling rootstock on more than 50? of their acreage. Many said they planned to have more as more young trees are planted. Seventy-six percent sell more than 75? of their crop fresh. Many said they sell only a small percentage (less than 5?) for processing. Much of the processing seemed to mean cider production (although we collected no data on this). Familiarity with and Use of Integrated Pest Management Most of the state's growers (32?) had at least heard of integrated pest management, and 90? knew of the Massachusetts IPM program. Respondents who said they were familiar with IPM were asked to rate a series of "selling points" of the program with respect to their importance to the respondent. Initially the scale was from 1 (very important) to k (not important), but when a number of growers said they did not feel that a selling point per- - 13 - tained to what they knew of 1PM, a category 5 (disagree) was added. Although this category was little used (only 9 respondents disagreed with 5 of the points), it gives an indication that tlie growers were really consi- dering their answers to these points, not just giving the expected response. Results are given in Table 1. The mean response is obtained by adding the numerical response (I-**) and dividing the number answering each question. A mean of from 1.0 to 2.5 indicates a positive overall response; 2.5 to k.O would be negative. In this survey, all the selling points fell in the positive range. Table 1. On a scale of 1 to '«; 1 = very important, '4 = not important (5 = disagree), please rate the following "selling points" of IPM. Points are ranked by the mean of the responses. Since "very important" = 1, the lower the mean, the more positive the response. 'Selling point" Mean response .^5 .^8 .'♦9 .71 .73 .75 .81 2 .21 Reduces damage to the environment Involves the safe use of pesticides increases farm profits by decreasing pesticide use Has a more positive image with neighbors/consumers Gives an unbiased opinion of pest problems Involves the use of natural enemies Controls yield and quality loss Frees you to use management skills elsewhere It is clear that reducing environmental damage, using pesticides safely, and increasing profits are the most commonly cited reasons for adopting IPM. The next four points are not quite so important. The last was closest to being a negative response. Many growers said they felt that 1PM took more time, an accurate comment based on requirements for scouting, training, weather monitoring, sprayer calibration, etc. It is interesting to note that, in general, respondents did not feel that "public relations" played an important part in their adoption of IPM. Many pointed out that the public knows very little about pesticide use or about the program. Some suggested that we should publicize it more, although a few thought Chat publicity would not be useful, or could even be counterproductive. Use of IPM-related Practices Most growers said they scout their acreage regularly. Fifty-four per- cent of respondents said they scout more than 50^ of their acreage weekly. Twelve percent said they do not scout regularly. The questions on scouting did not directly address the issue of use of traps, etc., which were covered under "methods most frequently used," so that it is possible that some growers' definition of scouting may not be as intensive as others. Of the growers who do scout, 86% said they scouted their acreage themselves, or assigned an employee to scout. Only 7% used private scouts, possibly a u - reflection of the relatively small size of most orchards in Massachusetts, and k% relied on monitoring by IPM personnel. Only one grower said he relied on a pesticide fleidman For his scouting. Over half (5'*.'*%) of the growers said they based their spray decisions primarily on information obtained through scouting, almost exactly the same number (5^.1%) who said they scouted their acreage weekly. Another 1 8% relied on information obtained through the county agent, and ]h% relied on the calendar. The ]2% who stated "other" all said they did not want to choose one method, but used some ccnnbination of methods. Table 2. How frequently do you use the following? {% each response) Frequently Sometimes Never Pest Alert message/Agents' newsletter Recommendations from UMass Extension Code-A-Phone message Sticky spheres for apple maggot fly Alternate row spraying Pheromone traps Leaf wetness machine Perimeter-only sprays 82.6 1^.0 3. A 71.3 25.3 3.'* 30.2 29.1 ^40. 7 31.3 2k. k '♦'♦.2 7.2 k}.k kS.k 1^.(4 20.5 65.1 11.9 6.0 82.1 0 27.0 73.0 Growers say they are using Extension material, since over 95% used the Pest Alert messages sent via the regional agents' newsletter and UMass Extension recommendations. Nearly 60% of respondents said they used the county-based Code-A-Phone message system. Over 50% used sticky spheres, and a similar number used alternate row spraying as a routine practice. About 2/3 of growers said they never jsed pheromone traps. Over 82% said they never used a leaf wetness machine. Sixty-five percent of the growers said they calibrate their sprayers at least once per season. It was difficult to tell how many did a detailed calibration. Some said that they check to see how much of a tank they have left after spraying a given area and base their "calibration" on that infor- mation. Surprisingly, 19% of respondents calibrate their sprayer less than once per season. However, this is offset somewhat by the 22% who calibrate twice per season, and the 13% who calibrate more than twice per season. Most growers use a high-volume sprayer primarily, fewer use a low-volume, and some used both. A few of the smallest growers surveyed use backpack- type sprayers. When asked about whether they had changed spray practices in the last ten years, 52% of those who responded said they sprayed less now. Thirty- six percent said they sprayed about the same, although many of these spe- cified that they felt they were using pesticides more intelligently as a - 15 - result of the I PM program. Overall, the average number of insecticides applied per season was 8.9: miticides, 1.9; fungicides, 11.9; and herbicides 0.9. We are presently analyzing data from a survey of actual grower spray records from 1983 to the present to determine if the data in the I PM impact survey are accurate. There is reason to believe, for example, that pesti- cide use by growers who employ private I PM scout/consultants is much lower than the state averages which survey respondents gave, clearly an "impact" of IPM. The impact survey did not address the issue of Dosage Equ i val ents, a measure of actual rates of pesticide used. Since I PM growers may use less than the maximum label rate, study of actual spray records to look at DE ' s applied may present a very different picture of pesticide use. These points will also be clarified by further analyses of the survey data. Usefulness of Pest Control Information The format of Table 3 'S similar to that of Table 1--a mean response on a range of 1 to A, in this case with 1 = "very useful" and ^4 = "not useful". There was also a response of 5 = "never used." A mean score of 2.5 or less indicated that more people gave positive ratings; higher than 2.5 indicated a negative rating. Table 3- Sources of pest control information. Information source Mean response Articles in Fruit Notes 1.33 March message 1 .50 Extension handbooks and manuals 1.66 Pest Alert message by mail 1.67 Talking to the regional Extension agent 1 .8A Pest Alert message by Code-A-Phone ] .Sh Pesticide dealers and salespeople 2.30 Private consultants 2.67 Neighboring farmers 2.75 Articles in trade magazines 2.98 Newspaper articles 3.58 Weekly IPM Pest Alert Messages, the New England Pest Control Guide, and the annual March Message were the three most frequently cited sources of infor- mation on pesticides. About equal numbers relied on regional extension agents, University Extension personnel, and agricultural chemical fieldmen for such information. Altnough almost 25? of respondents said they "never" used University Extension personnel d i rect 1 y as a source of information, it should be noted that the three most frequently cited information sources on pesticides originate with University faculty and professional staff in Entomology and Plant Pathology. A majority of growers said they "never" obtained pesticide information from a neighboring farmer or an agricultural magazine. Although the vast majority said they "never" used private con- sultants, it should be remembered that only 7% of growers surveyed in the study used private consultants for IPM scouting and advice. 16 Pest Problems Table 5 contains information about which pests growers perceive to be a problem in their orchards. The definition of "prob lem"--whether it meant a potential problem or a situation which was not being adequately control led-- was left to the respondent. Most seemed to use the latter definition. The choices are ranked by the percent of respondents who answered "yes." Table 5- Which pests are a problem on your farm? Tota 1 West Central Southeast Scabz 65% PC 76% ERM 81% Scab 62% ERM 62% TPB 75% Scab 6^4% PC 50% PC 60% Scab 68% TPB 58% LM A6% TPB 57% ERM ^9% PC ^49% SJS 50% LM kn AMF ki\% LM ^♦5% ERM 50% BR 39% BR k2% BR 37% GAA A6% AMR 3^% LM 35% SJS 35% BR 38% SJS 3'4% GAA 30% AMF 28% AMF 23% GAA 29% SJS 26% GAA 22% TPB 8% ^Scab=apple scab; ERM=European red mite; PC=plum curcul io; TPB=tarn i shed plant bug; LM=leafminers; BR=black rot; AMF=apple maggot fly; SJS=San Jose scale; GAA=green apple aphid. Most growers reported Scab, ERM, PC, and TPB as problem pests. However, the relative importance given these pests varied among regions of the state. Three-fourths of the growers in the western part of the state regarded plum curcul io to be a problem while less than half those in the central section responded positively. The situation is almost exactly reversed in the case of European red mites, the number one perceived problem pest in central Massachusetts, but not widely regarded as a problem in the west. The southeast, meanwhile, was apparently untroubled by tarnished plant bug. While about the same number of growers considered leafminers to be a problem in central (^5%) and southeastern (^46%) Mass., only about 1/3 of western Mass. growers considered it so. SJS was also perceived as rela- tively more a problem by central and southeastern growers. We do not have data to indicate whether these differences are a matter of grower attitudes, or whether there is an actual difference in pest pressure among the three regions. In either case, this unexpected result deserves further investiga- t ion. Cone 1 us ion We are pleased to conclude from survey results that Massachusetts com- mercial apple growers are highly aware of tPM, that a sizable portion have adopted sound IPM practices, and that traditional Cooperative Extension delivery methods are rated as very useful sources of information on pesti- cides and pest control. We would like to express our appreciation to the growers who participated in the survey for their time and cooperation. ***** - 17 LARGE CRABGRASS - A PROBLEM WEED Prasanta C. Bhowmik Department of Plant and Soil Sciences University of Massachusetts Common name; Large crabgrass or hairy crabgrass Botanical name; D i g i tar ia sangui nal i s (L.) Scop. Other names; Hairy crabgrass, purple crabgrass, crow foot, Polish millet, pigeon grass, and finger grass. Crabgrass is a problem weed in lawns, field crops, vegetables, and turfgrasses. Orchard areas are no exception. Crabgrass belongs to the genus Pi g i tar i a . The word digitaria is derived from the Latin word 'digi- tus' meaning finger. The flower spikes (Fig. 1) or seedheads of crabgrass diverge from a single point like the fingers of a hand. The name 'crabgrass' is given to the grass because of the crablike branching habit of its prostrate stems. S imi 1 ar spec i es The two closely related species of crabgrass in the United States are large or hairy crabgrass (Digitaria sangu inal is) and small or smooth crabgrass (Digitaria i schaemum). Origin Crabgrass was grown in Switzerland by the Stone Age lake dwellers. As early as 2700 B.C., a form of crabgrass known as foxtail millet was grown in China and considered an important food source. Prehistoric man grew crabgrass in India, utilizing it in porridge and bread. Crabgrass was introduced into the U.S. in iS'tS by the U.S. Patent Office. At that time the Patent Office (then doing work of the future Department of Agriculture) elected to introduce crabgrass to American far- mers to help alleviate the acute need for good forage which resulted from the importation of thousands of domestic animals. It was soon forgotten to promote the new introduction. In the late 19th Century, a wave of immigrants from Europe arrived on America's shores. With them came the real invasion of crabgrass. Most immigrants brought along crop seeds. The essential grain to many of them was "manna grits", a variety of crabgrass and a form of millet native to central Europe. Crabgrass thrived in its new home, producing bountiful crops, but it was soon abandoned in favor of corn and wheat. Features which made crab- grass a valued crop now made it a tenacious weed. Large crabgrass is considered as a problem weed in 56 countries and 33 different crops in the wor 1 d . 18 ► Seedhead Figure 1. Large Crabgrass 19 D'jscr i pt ion The leaf sheaths oF large crabgrass seedlings are tinged purple and are covered witH long stiff hairs. The ligule is membranous, flat at the top, and smooth (Fig. la). A ligule is a thin membrane or row of hairs at the top of the junction of the leaf sheath and the leaf blade. Large crabgrass 3nd small crabgrass are the only species of the grass family which have a membranous ligule. Auricles are absent. Auricles are the appendages pro- jecting around the stem from both sides of the collar. The first leaf is only about twice as long as it is wide. It is tinged light purple and has a white strip running down the center. Both sides have silky, shiny hair. Biol ogy Large crabgrass, a summer annual, is a member of the grass family. It is purplish or green and has very hairy leaves and sheaths. Leaves are 6 to 8 mm wide and 5 to 15 cm long. The stems are spreading and much branched. Roots develop at nodes on the prostrate stems (Fig. 1). Large crabgrass reproduces by tillers and seeds. This weed has a pro- lific tillering or branching habit. Just a few plants can spread rapidly and cover considerable area. A single plant is capable of producing 150 to 700 tillers and 150,000 seeds. Plants can produce seeds at mowing heights as low as 6 mm. If top growth is mowed, two or three seed crops may form in a single growing season. Seeds germinate best from mid-spring to late summer. Large crabgrass seeds are dormant for a short time after they shed. Large crabgrass con- tinues to grow until mid-summer when days become shorter. Vegetative growth slows down and plants enter their reproductive stage. Purplish seed heads form until frost kills the plants. Plants that emerge early in the season and have a long period of vegetative growth are much larger and more competitive than plants that germinate late in the season. Large crabgrass is a serious weed of cultivated crops, lawns, nur- series, orchards, and pastures. Once established, large crabgrass tolerates both high temperatures and dry weather conditions. Control of Crabgrass The basic principle of a large crabgrass control program is to prevent rei nf estat ion by seed. Controlling seed production for several years will help reduce the viable seed supply. Large crabgrass can not be controlled in one growing season because of the great number of viable seeds that accumulate in the soil from years of infestation. A good weed management program in a fruit orchard is one that consists of both cultural and chemical methods of weed control. Satisfac- tory control requires several years of conscientious adherence to a good control program. 20 - Cultural Control Mechanical control methods include mowing, disking, and cultivating. Mowing is very effective in controlling large crabgrass because of its annual growth habit. However, this method must be repeated to control late germinating crabgrass and other weeds. Chemical Control A good weed management system includes both knock-down herbicides and residual herbicides. The knock-down herbicides include PARAQUAT CL^ (paraquat) and ROUNDUP" (g 1 yphosa te) . Paraquat is a contact type herbicide. It- requires uniform application for best results. On the other hand, glyphosate is a systemic or translocated type herbicide. It can provide effective control of perennial weeds under orchard situations. Do not apply to trees less than two-years old. Prehavest interval is 14 days. Do not allow spray to drift to green foliage, green bark, or suckers. The residual herbicides are those that provide weed control over a period of time. These include DOWPON M^ (dalapon), KARMEX^ (diuron), PRINCEP^ (simazine), CASORON^^ (d i ch loben i 1 ) , and SINBAR^ (terbacil). The purpose of combining knock-down herbicides and residual herbicides is to provide season-long control of annual weeds (grass and broadleaf species) and perennial weeds. For more information regarding rates of herbicide application, com- binations of herbicides, and specific comments on safety and precautions, consult the latest edition of New England Chemical Weed Control for tree f ru its. ***** THE 1985 ALAr"^ SURVEY Wes ley R. Aut io Department of Plant and Soil Sciences University of Massachusetts As many of you know I conducted a survey of Massachusetts apple growers as to their use of Alar". The questionnaire was sent to all of the people on the tree fruit mailing lists of the regional fruit agents. It included the following questions: 1. Total acreage in apples? 2. Acreage of bearing apples? 3. Total acreage of Mcintosh? '♦. Acreage of bearing Mcintosh? 5. Percent bearing Mcintosh receiving Alar^ 6. Percent of other cultivars receiving Alar^ 7. How would the loss of Alar"^ affect you? 21 Eighty-five responses were received, representing 5^3^ acres of apple production (68^ of the Massachusetts apple acreage). Table 1 shows the num- bers of acres of trees fitting into the various categories. it is important Table 1. 1985 Alar^-use survey results. Catagory Acreage Percentage Total acreage of apples Mc 1 ntosh Bearing trees Mc 1 ntosh Other cul t i vars Alar^^-treated Mc I ntosh Other cultivars 5^31 3^471 hhhO 2877 1563 3157 2376 781 68? of Massachusetts total (>h% of survey 82? of survey 65? of bearing, 53? of survey 35? of bearing, 29? of survey 71? of bearing, 58? of survey 83? of bearing Mcintosh 50? of other bearing cultivars to note that 6^4? of our total acreage is in Mcintosh, and 53? of all the trees in Massachusetts are bear i ng Mc I ntosh , Eighty-three percent oF all bearing Mcintosh trees received Alar^ in 1985, representing 75? of the total Alar"^ use in Massachusetts. With that in mind the answers to the last question were not at all surprising. Most people stated that large quantities of fruit would be lost to drop, and there would be an overall loss of fruit quality without the use of Alar". However, in addition many growers felt that the loss of Alar- would severely jeopardize their business, and several suggested that they would go out of business altogether if they could not use Alar". The use of Alar" in Massachusetts obviously is extensive, and if Alar" was not available many changes would have to occur in the way that we grow apples. These changes include alterations in cultivars, cultural practices, and storage conditions. Later Fru i t Notes articles will discuss some of the practices which may partly replace the use of Alar". ***** 22 POLLINATION OF BLUEBERRIES, STRAWBERRIES AND BLACKBERRIES James N. Moore Department oF Horticulture and Forestry University of Arkansas, Fayetteville, AR Knowledge of the pollination requirements of fruit crops is essential to fruit producers, since the potential magnitude of the crop is determined by the extent of successful pollination and fertilization of the flowers at the time of bloom. An understanding of the mechanisms of pollination of his fruit crops enables a fruit grower to provide those conditions which lead to satisfactory fruit set. B 1 ueber r ies At the outset, we can make two definite statements concerning pollina- tion of blueberries: 1) insect pollination is obligatory and 2) bees are the principal pollinators. The necessity of insect pollination of blueberries is determined by the morphology of the flower. The blueberry flower has all the characteristics of an entomoph i lous (insect attracting) flower. These characteristics are: 1. Corolla of the flower in shape of a tube, opening only at tip (prevents wind pollination). 2. Pistil of flower extends well beyond anthers, and stigma flanged to inside, preventing unaided self-pollination. 3. Nectary glands produced at base of ovary to attract insects. h. Fragrance produced to attract insects. 5. Pollen heavy, clumping, not readily wind-borne. Thus, the construction of the flower effectively suppresses both wind pollination and unaided self-pollination. However, as insects enter the corolla tube seeking the nectar at the base of the ovary, their bodies collect pollen as they rub on the anthers and deposit pollen on the exposed stigmas of flowers subsequently visited. Numerous research studies using various types of caging have shown that bees are the principal effective pollinators of the blueberry. Most repor- ters state that both honeybees and bumblebees are effective pollinators, but in many blueberry producing areas, native bee populations are considered inadequate for complete pollinations, and honey-bee colonies are introduced into the fields. - 23 - Inadequate poIUnation of blueberries may be expressed in two ways. Flowers receiving no pollination will abscise without fruit set. Flowers partially pollinated may set but produce small fruits. The blueberry nor- mally contains up to 85 seeds, and seed number and fruit size have been shown to be highly correlated. Thus, any reduction in seed set will likely result in production of smaller fruit. Studies of the effect of cross- vs self-pollination of the highbush blueberry have not all been in agreement, but most careful studies show that pollination with pollen of a different cultivar results in slightly increased fruit size and sometimes earlier ripening fruit. Most studies of the rabbiteye blueberry agree that cross-pollination is important and that two or more cultivars should always be planted together. Blueberry cultivars appear to differ in attractiveness to bees. Two cultivars identified as "unattractive" are 'Coville' and 'Earliblue', and these require more honeybee colonies per acre for adequate pollination. Attractiveness of cultivars to bees seems to be conditioned by nectar volume and nectar sugar content. Blueberries are generally not a preferred Pood source For honeybees. Blueberries are a very poor source of pollen. Consequently, bees may overfly blueberries to forage on other plant species nearby. A major problem in Arkansas fields is the presence of dandelions during the blue- berry bloom period. Bees may be seen foraging on dandelions rather than blueberries. Since bees tend to continue foraging on a plant species that they start on, we recommend that bee colonies not be placed in blueberry fields until the blueberries have some open blossoms. Do not withhold bees past 25 percent open bloom, however, or reduced set will result. Pistil receptivity lasts only 5 to 8 days. I consider the bumblebees to be more effective pollinators for blue- berries than the honeybees. They are less intimidated by adverse weather and bumblebees can be seen foraging in blueberry plantings on cold, windy days (common in Arkansas during blueberry bloom) when honeybees remain in their hives. Unfortunately, however, bumblebee pollination is not reliable due to population fluctuations. Modern agricultural practices have greatly reduced bumblebee (and other native bee) populations in many areas, and the only recourse to ensure adequate pollination is to place honeybee colonies in the fields. Generally, a set of 80 percent of the blossoms is needed to yield an excellent crop of blueberries. To achieve this goal, recommendations for introducing honeybees into blueberry plantings have been made by most blue- berry producing states. The numbers of colonies recommended per acre vary among states and are associated with the extent of native bees. Michigan, for example, with 12,000 acres of blueberries, recommends up to 5 colonies per acre. In Arkansas, with our less concentrated acreage and still available native bees, we recommend 1 to 2 colonies per acre. A rule of thumb developed in Michigan is that i f 4 to 8 bees are observed per bush when temperatures during bloom are in the 70s and 80s (degrees F), pollina- tion will be adequate. - 2'» The inescapable conclusion to blueberry pollination is that blueberries must be pollinated by bees, and in most areas native bee populations are insufficient to provide adequate pollination. St rawber r ies Most modern strawberry cultivars produce hermaphroditic Flowers, and the arrangement of the flower parts (pistils surrounded by taller stamens) encourages self-pollination. However, a characteristic common to many cultivars is that primary flowers often lack well developed stamens and may not be well pollinated. Research conducted in Arkansas has shown that strawberries benefit greatly from insect pollination, and that bees are important pollinators. Experiments conducted over a period of four years showed that excluding insects by covering strawberry plots with l8 mesh screen wire during bloom resulted in yield reductions of an average of 50 percent and fruit size reduction of up to 31 percent. Furthermore, a high percentage of fruits produced on caged plants were badly malformed, exhibiting evidence of incomplete pollination. Most strawberry growers do not provide bee colonies to their fields. However, most strawberry plantings are small and apparently attract adequate numbers of native bees. For large plantings, or plantings located near large plantings of other bee-attracting crops, growers should consider providing additional bees in order to achieve maximum yields oF good quality berr ies. Blackberries Many species and some cultivars of blackberries are self-unfruitful and must be cross-pollinated for Fruit set to occur. Most erect, thorny culti- vars grown in Arkansas are fully self-fertile and require no other pollina- tor. There is little information on pollinating agents for blackberries. Both honeybees and bumblebees readily forage on blackberry flowers. Wind may also be an important pollinating mechanism, since the pollen is produced in abundance, and the flower is so constructed that wind-borne pollen may readily reach the pistils in the Field. Experiments conducted in Arkansas compared blackberry Fruit set under three conditions. Plants in bloom were placed in a greenhouse in which both wind and insect pollination was excluded, other plants were placed in a field and caged to prevent bee, but not wind, pollination, and other plants were uncaged in the field. The lowest percent fruit set and smallest berry size was produced by the greenhouse-grown plants. Good fruit set and normal fruit size was produced by both groups of field-grown plants. The conclu- sion was that insect pollination was not essential for greater yields. No doubt, under natural conditions, bees are also effective in distributing pollen in blackberry Fields. 25 - CONCLUSIONS Research has shown that bees are i ndi spens ib le for blueberry pollina- tion, highly desirable for strawberry pollination, and contribute (with wind) to blacl than non-IPM growers (82^ and 60%, respectively). About 75^ of the growers in both groups attended the annual New England Fruit Meetings. However, an interesting difference between the two groups occured in their awareness of the effective use of pesticides, as illustrated in Table 2. Both groups were equally likely to calibrate at least once per season, but IPM growers were almost 3 times more likely to calibrate their sprayer 22 - more than once per season than non-IPM growers. (There was no substantial difference in the type of sprayer used, except that all the growers who use backpack-type sprayers were in the IPM category.) Further, a majority of IPM growers were equally likely to spray less or the same compared to ten years ago. The percentage saying they spray more often was fairly small in both cases. Table 2. How often do you calibrate your sprayer? IPM growers Non-IPM Growers Less than once per season 18.6* 19.0* Once per season 27.9 61.9 More than once per season 53-5 19.1 Do you spray More? 9.3 15.0 Less? 60.5 '♦2.5 The same compared to 10 years ago? 30.2 't2.5 *Percentage of respondents in each category. Table 3 indicates that a substantial majority (72^) of IPM growers used scouting to decide when a pesticide treatment was needed, and another 11% used a combination of techniques ("other"). Less than half of the non-IPM growers gave these two responses. While nearly a third of the non-IPM growers said they used the county agent for information on when to spray, in most cases, we believe, this means that they used the Pest Alert and Code-A-Phone messages. Thus, while some growers may be using IPM-generated information, they may not be making the best use of this information if they are not backing it up with their own scouting observations. It is possible that reliance on the Pest Alert messages may be counterproductive if growers treat for pests mentioned in the message regardless of whether they actually have a problem with these pests on their farm. Table 3. How do you decide when a pesticide treatment is needed? IPM Growers Non-IPM Growers Neighbors are treating 0* 2. A* Scouting determines need 71.7 36.6 By the calendar 10.9 17.1 County agent information** 6.9 31.7 Other 10.9 12.1 ♦Percentage of respondents in each category, **Pest Alert messages. 23 - From Table ^, it is clear that the IPM growers were spending less, applied fewer insecticides and miticides, and achieved somewhat better pro- duction than non-iPM growers. In the survey we asl60 Acres $171.11* 7.2 2.0 10.8 1.4 459.05 ^Average response in each category. There are several reasons to believe that small growers have had less exposure to Integrated Pest Management than large growers, and that this may be related to their increased pesticide use. For a variety of reasons, - 25 small growers may be less likely to attend the grower meetings where IPM training has been presented, and in fact, the percentage of such growers attending all grower meetings was smaller than the overall average. Moreover, the majority of orchards on the IPM pilot program (1978-1982) were large, and all the growers on this survey who used private consultants had orchards larger than 60 acres. In addition, there may be less incentive for small growers to reduce pesticides costs, since their costs are already comparatively less. But smaller growers have a strong potential for the use of integrated pest management in their orchards, since a grower with a few acres can often be more flexible than a grower who manages a large acreage. For example, a large grower may need 2 or more days to spray their entire orchard while a small grower may accomplish this task in less than a day. As a consequence, the use of post-infection scab sprays or insecticides based on scouting results (eg., for plum curcul io) may be less of a problem for the smaller grower. It should be noted here that the respondents with less than 20 acres who do scout had the lowest pesticide costs on the survey--$121 per acre, and the lowest use of mi t ic ides--l .3 applications per season. We would anticipate that with better use of IPM techniques this group also could substantially reduce their use of insecticides and fungicides, reaping both economic and environmental benefits. Summary and Conclusions In summary, principal reasons for adopting IPM were safe use of pesti- cides, increases in farm profits, control of crop yield, and a more positive image with neighbors and consumers. Compared to non-1 PM growers, IPM practitioners tended to be somewhat younger and with less farming experience; were more likely to use sticky spheres, pheromone traps, leaf wetness machines, and alternate row spraying; were 3 times more likely to calibrate their sprayer more than once per season; reported higher per acre yields, but lower pesticide costs, and somewhat lower numbers of insecticide and miticide applications. We conclude that growers who adopt integrated Pest Management experi- ence benefits in several areas, and that such benefits can more than justify the cost of hiring a private IPM scout/consultant or alloting the time to implement an IPM system on their own. Issued by the Cooperative Extension Service, E. Bruce MacDougall, Dean, in furtherance of the Acts of May 8 and June 30, 191^; United States Department of Agriculture and Massachusetts counties cooperating. The Cooperative Extension Service offers equal opportunity in programs and employment. COOPERATIVE EXTENSION SERVICE U S DEPARTMENT OF AGRICULTURE UNIVERSITY OF MASSACHUSETTS AMHERST MASS 01003 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, S300 BULK RATE POSTAGE & FEESPAID USDA PERMIT No G?G8 Fruit Notes Prepared by: Department of Plant and Soil Sciences Massachusetts Cooperative Extension, University of Massachusetts, United States Department of Agriculture and Massachusetts counties cooperating. Editors: W. R. Autio and W. J. Bramlage Volume 51, No. 4 FALL ISSUE, 1986 Table of Contents Redcort: A Superior Strain of Cortland Picking up Apple Drops to Prevent Buildup of Apple Maggot Flies in "Organic" Orchards Mammal Control Sampling Orchard Soils Apple Replant Problems Update on Disease-Resistant Apples Peach Rootstocks in New Jersey Rootstock Evaluation in Massachusetts Cultivars of Apples for Massachusetts REDCORT: A SUPERIOR STRAIN OF CORTLAND Wesley R. Autio Department of Plant and Soil Sciences University of Massachusetts Apple growers are always looking for strains which have superior color to the standard strains. Redcort (sold by Hilltop Orchard and Nurseries, Inc., Hartford, Michigan) is one such Cortland strain. It was selected as a branch mutation on a standard Cortland tree in Marlboro, NY. Redcort and Cortland trees on M7A rootstocks were planted in I98O at the Horticultural Research Center, Belchertown, MA. In I985 fruit were har- vested on September I6 and September 23 for evaluation. Measurement of the internal ethylene concentration was used to determine differences with respect to the time of ripening. As apples ripen the ethylene concentration in the core rises sharply, providing a means of pinpointing the time of ripening. Both the internal concentration at harvest and the number of days after harvest required for the core ethylene concentration to reach 1 ppm are reported in Table 1. As the fruit matures the number of days required for the internal ethylene concentration to reach 1 ppm declines, so a more mature fruit would have a higher internal concentration at harvest and would require fewer days to reach 1 ppm. There were no differences between Redcort and Cortland in these two measurements for the two harvests, so our data suggest that Redcort and Cortland fruit ripen at the same time. Table 1. Ripening of Redcort and Cortland fruit in I985. Harvested 9- ■16-85 Harvested 9' -23-85 Strain Core ethylene concen. (ppm) Days to 1 ppm ethylene Core ethylene concen. (ppm) Days to 1 ppm ethylene Redcort Cortland 0.02 a* 0.07 a 5.0 a 0.10 a 0.10 a 3.2 a 3.3 a *Within columns, means not followed by the same letter are significantly different at the S% level. On September 23 fruit weight, diameter, firmness, and soluble solids were also measured (Table 2), but no differences existed between the two strains for any of these parameters. The percentage of the surface of the fruit which was red also was assessed on September 23, and Redcort fruit were significantly redder the Cortland fruit. Redcort fruit averaged 86% red, whereas Cortland fruit averaged only 58^ red. Fruit from these trees were placed in air and CA storage for evaluation of storability. Table 2. Fruit characteristics of Redcort and Cortland fruit harvested 9-23-85. Strain Fruit weight (lbs.) Fruit diameter (in.) Fruit f irmness (lbs.) Total soluble sol ids {%) Surface red color {%) Redcort Cortland 0.53 a* 0.52 a 3.42 a 3.38 a 14.9 a 15.4 a 13.9 a 14.0 a 86 a 58 b *Within columns, means not followed by the same letter are significantly different at the 5% level. When storage was terminated fruit were moved to room temperature. After 24 hours firmness was measured, and after 7 days the incidences of scald, senescent breakdown, bitter pit, and decay were measured. There were no differences between Cortland and Redcort fruit after 19 weeks of air storage (Table 3). After 17 weeks of CA storage followed by 14 weeks of air storage (Table 4) Redcort and Cortland fruit displayed similar firmness values and percentages of senescent breakdown, bitter pit, and decay. However, scald was more prevalent on Cortland fruit, reflecting the fact that scald forms more readily on the green portions of fruit. Table 3. Characteristics of Redcort and Cortland fruit after 19 weeks of air storage. Strain Flesh f i rmness (lbs.) Scald Senescent breakdown (^) Bitter pit {%) Decay Redcort Cortland 8.6 a* 8.6 a 7 a 10 a 7 a 10 a 7 a 8 a 1 a 2 a *Within columns, means not followed by the same letter are significantly different at the 5% level. After one year's observation Redcort fruit appear to be similar to Cortland fruit except for the much higher degree of coloring. The higher coloring translates into more fruit meeting the U.S. Extra Fancy grade. Table A. Characteristics of Redcort and Cortland fruit after 17 weeks of CA storage followed by 14 weeks of air storage. Strain Flesh firmness (lbs.) Scald Senescent breakdown {%) Bitter pit Decay Redcort Cortland 12.1 a* 12.0 a 73 b 95 a 6 a 13 a k a h a 10 a 8 a *Within columns, means not followed by the same letter are significantly different at the S% level. PICKING UP APPLE DROPS TO PREVENT BUILDUP OF APPLE MAGGOT FLIES IN "ORGANIC" ORCHARDS Ronald J. Prokopy Department of Entomology University of Massachusetts The apple maggot has been a key pest in eastern and midwestern apple orchards ever since it expanded its host range from hawthorn (its native host) onto apple sometime mid 19th century. Before the advent of inorganic pesticides such as calcium arsenate and lead arsenate in the early part of the 20th century, the only effective method of controlling the apple maggot was to pick up dropped fruit from beneath apple trees to prevent the larvae from forming pupae. So long as drops were picked up on a frequent schedule, this practice precluded pupal buildup beneath orchard trees and thereby pre- vented wi thi n-orchard fly emergence the next summer. It could not affect immigration of flies from sources outside an orchard, however. Nowadays, with so many effective pesticides available to control the apple maggot, probably few, if any, commercial apple growers in eastern or midwestern regions bother with picking up maggot- i nfested drops. The situation is very different in California, however. In an earlier article (Fruit Notes 49(2) : 16-18) , I gave a brief account of how the apple maggot fly was first detected in California in August of 1983 and how it has created a state of alarm among many apple growers there. Indeed, twice within the past year, 1 have been called upon to file legal declarations on various aspects of apple maggot management. One of the declarations was in behalf of "California Organic Apple Growers" and supported a proposed program of apple maggot control that did not involve use of pesticides. If such a program were to prove effective, an organic apple grower would not then be required by law to have his orchard sprayed with pesticide by the State to control maggot. If not, then the grower would have to submit his orchard to a series of pesticide sprays to ensure that maggot fly popula- tions were not building up over successive years within the orchard- There are 3 elements in the non-pest icidal program of apple maggot control in California: (a) Use of sticky red spheres hung in apple trees to capture the flies and thereby prevent (or greatly reduce) egglaying (see Fruit Notes 50(2):2-5); (b) Twice-weekly removal of drops from beneath the trees to prevent larval exit from any infested fruit; and (c) Refrigeration or processing of tree-harvested fruit to prevent larvae from maturing into pupae. No one of these elements alone is likely to completely prevent apple maggot buildup within an orchard. Together, they ought to work as well as frequent pesticide treatments. A principal point of debate over the efficacy of this non-pest ic idal approach has been the frequency with which dropped apples must be picked up to prevent any larvae from emerging and forming pupae in the soil. Because picking up infested drops constituted the first line of defense against the apple maggot until earlier this century, a good deal of work was conducted on this subject by pioneering apple maggot researchers such as J.F. Illingworth of Cornell, W.C. O'Kane of New Hampshire, and W.H. Brittain and C.A. Good of Nova Scotia. It is this work that gave rise to the recommen- dation that an effective schedule of drop pickup should be twice per week. In recent decades, however, little or no research has been carried out along these lines. Thus, we decided to initiate 3 small experiments to determine if the findings of the pioneering workers were still valid. In the first test, we placed 5 wire baskets (18 x 30 inches) under each of 3 unsprayed Early Mcintosh trees (an early-season variety) on Orchard Hill in Amherst. The baskets were in place from June 15 (before any maggot flies were mature) until August 8 (the date by which all but a handful of fruit had fallen). Every 3-^ days, we collected each fruit that dropped into the baskets and examined it carefully for presence of an exit hole made through the fruit skin by an emerging larva. After examination, we put the drops in wire baskets beneath non-fruiting trees and thereafter examined them for exit holes every 3-^ days until all had completely rotted. The results (Table 1) show that of the ^24 dropped fruit collected over the course of the season, only 2 (0.5%) showed a larval exit hole on the day of drop pickup (0 to 3 or 4 days after drop), and only one additional fruit (0.2%) showed a larval exit hole when examined 3-k days after drop pickup (3 or 4 to 7 days after drop). Each of these 3 fruit had fallen at least 2 weeks after the optimum time for fruit harvest (July 8). (Note: in this abandoned orchard optimum harvest was about 1 month earlier than in commer- cial orchards.) In addition to examination of drops, 25 on-tree fruit were sampled every 3-4 days from July 8 - August h for larval exit holes. None was found. However, one fruit that had dropped and was caught in a crotch between tree branches was nearly rotten when found and did have larval exit holes. Several bushels of fruit were picked up beneath these 3 trees on July 15 and were placed over wire traps to obtain pupae. The average yield was about 6 pupae per apple, revealing the high level of fruit infestation. Table 1. First appearance of exit holes of apple maggot larvae in Early Mcintosh drops. NO. FRUIT IN WHICH A LARVAL EXIT HOLE FIRST Af REARED AT SUCCESSIVE INTERVALS (DAYS) AFTER FRUIT DROP PICKUP* Day of J^ 6^7 10-11 U-l'* 16-17 20-21 More Than Drop pickup Days Days Days Days Days Days 21 Days No. D/-op Pickup Drops July 8 38 11 116 15 85 18 35 21 69 25 44 28 12 31 13 Aug. k 9 8 3 0 0 0 0 0 0 0 2 0 0 TOTAL 424 0 0 2 2 26 0 0 0 36 77 0 2 22 53 8 0 0 13 16 6 0 7 19 27 14 1 5 9 14 6 0 0 3 3 6 0 0 3 2 4 G 0 0 4 2 0 0 1 1 1 1 14 72 158 150 22 % FRUIT WITH AN EXIT HOLE 0.5 0.2 3.3 17.0 37.3 35.4 5.2 1.2 *Once an exit hole was detected in a fruit, that fruit was discarded. In the second test, carried out at the Horticultural Research Center at Belchertown, we inserted 4 apple maggot eggs into each of 5 previously uni- fested Mcintosh apples (a mid-season variety) during each of 4 weeks from late July until late August. We placed a cloth bag over each fruit to catch the fruit when it dropped. We looked at each cloth bag for drops every 3-4 days until all fruit had dropped (first drop was August 9> last drop was October 4). Of the 80 fruit, not a single larval exit hole appeared at the time of drop pickup nor even within the first week after drop pickup. Each fruit did eventually produce mature larvae, however. In the final test, we placed cloth bags on September 10 over 1121 Crataegus mol 1 i s (hawthorn) fruit heavily infested with apple maggot larvae. The fruit are a native host of this species. Every 3-4 days until the last fruit had fallen, new drops were examined for larval exit holes. The results (Table 2) show that 203 fruit (18%) exhibited an exit hole made by a larva sometime within the period between dropping and examination. Table 2. Appearance of exit holes of apple maggot larvae in Crataegus mo 1 1 i 5 hawthorn drops. DATE OF W. DROPS IN WHICH A LARVAL EXIT HOLE DROP PICKUP DROPS APPEARED ON DAY OF DROP PICKUP NO. %_ Sept. 15 9^ 0 0 19 90 0 0 23 305 38 12 27 206 Ith 21 Oct. 1 295 86 29 4 99 29 29 8 25 4 16 12 7 _2 29 TOTAL 1121 203 l8 What conclusions can be drawn from this work? By and large, our results do indeed confirm the findings of the earlier researchers in that picking up dropped fruit twice per week in commercial apple orchards is an effective method of preventing entry of apple maggot larvae into the soil. In fact, our results suggest that in nearly all situations, picking up drops once per week should be sufficient. Only in cases where the variety is an exceptionally early maturing one (for example. Early Mcintosh), and where harvest of on-tree fruit is delayed well beyond the optimum for good commer- cial quality, should it be necessary to pick up drops as often as every 3-4 days. Even then, use of sticky sphere; to capture the adults should reduce larval infestation to such a low level that larval exit from fruit could be delayed beyond that observed in this study. We speculate that this could be so on the basis that the comparatively earlier exit of larvae after fruit drop from C_^ mo 1 1 i s hawthorn trees than after fruit drop from Early Mcintosh trees may have been in response to the more limited fruit flesh resources of the hawthorn fruit (about 1/2 inch diameter) than the Early Mcintosh apples (about 1 1/2 inches diameter). In other words, we postu- late that under conditions where larval infestation is low and fruit size is moderate or large, as ought to be the case in a commercial apple orchard in which sticky spheres are used, larval exit from dropped fruit may occur later than where larval infestation is high or the fruit is exceptionally sma 1 1 . Further research is needed to evaluate this speculation and to deter- mine the optimum frequency of apple drop pickup under existing California orchard conditions. For non-pesticide-using apple growers in Massachusetts, the combination of trapping with sticky red spheres and picking up maggot- infested drops once per week should very effectively prevent any apple maggot buildup, though it will not prevent entry of immigrating flies from outside the orchard. ***** - 7 - MAMMAL CONTROL Wi 1 I iam G. Lord Plant Science Department University of New Hampshire Deer Deer feeding causes significant injury to many apple orchards. Injury to young plantings can be devastating, especially if deer pressures are such that trees sustain multiple browsings during both the dormant and growing seasons. Injury to older, fruiting trees will consist of browse damage to vegetative shoots (usually not serious) and flower bud and spur damage that can result in significant, immediate, and long term crop losses. There are several management options that can be used to alter deer feeding patterns and minimize damage. However, many sites will require fencing systems that exclude deer completely to prevent serious economic injury. In locations with a history of high deer population density and crop damage, a deer management program including fencing needs to be an integral part of any orchard design and management plan. In many cases, establishment of exclusionary fencing should precede orchard establishment. Electric Fencing The development of high-tensile, suspended electric fences charged with low impedance energizers, coupled with their lower relative cost of cons- truction when compared to traditional woven wire fencing systems, has increased the use of electric fencing to control deer. Two basic electric fence configurations are being employed--a vertical, 6- or 7-wire design and a sloped, 7-wire design. The 6- or 7-wire vertical design has been readily accepted by growers since it is easy to construct and maintain. These vertical fences have been effective in controlling deer damage, especially on small and intermediate sized acreages experiencing low to moderate deer pressure. They do invite more deer interaction than 3-dimens ional (sloped) configurations. The lowest wire should be a maximum of 10 inches above the ground with the remaining wires spaced at 8 to 10 inches. Vertical electric fences may more effectively control jumping deer if outfitted with a charged "outrigger" wire. A single, charged wire is set 38 inches outside the vertical fence at 15 inches above the ground to add a 3-dimens ional barrier effect to be a vertical fence. The sloped, 7-wire electric fence design has been effective in controlling high deer pressure on larger acreages. It presents deer with both a 6-foot deep barrier and a shock upon contact. The fence slopes up from the ground (and away from the crop) to an outside height of h feet. Wires are spaced at 12-inch intervals. - 8 - The use of bipolar low impedance fence energizers is often employed to increase effectiveness of these electric fences by providing control (shock) when animal feet are not grounded (such as on frozen ground). Construction and maintenance of electric fences needs to be considered carefully. Always follow manufacturers' fence construction specifications, paying particular attention to construction of corner and braced assemblies. Electrify and properly ground the fence (or completed fence sections) as soon as they are erected. it is important that deer respect the fence barrier from their first encounter. Control of vegetation and woody growth that may contact the fence is required for maximum effectiveness. Fence voltage needs to be checked monthly at the farthest point from the charger to insure that a charge of approximately 3000 volts is being maintained. Routine tension and equipment checks to maintain manufacturers' specifications is required. Woven Wire Fencing Vertical, woven wire fencing systems have been the standard control measure recommended for the protection of large acreages experiencing high deer pressure. Typically, these fences consist of 6" x 12" wire mesh 8 feet high. Additional strands of barbed wire are added to the top of the fence to extend the fence to 10 feet in height. Woven wire fencing is highly effective if properly maintained. However, its high relative cost and maintenance requirements limit grower acceptance of woven wire fence. Repel lents A variety of repellents have been developed to deter deer feeding pressure. While all of these have some effectiveness for short-term control, none is effective in situations of moderate to heavy deer pressure. Repellents are classified according to their basic mode of action. Some that are taste repellent and some produce an odor offensive to deer. Among those available Thiram^, a taste repellent, and a fatty acid (Hinder^), an odor repellent, are most effective. These materials are also effective against rabbit feeding damage when used according to manufac- turers' instructions. Several non-commercial, odor repellent materials will provide some deer repel lency action under low deer pressure situations. Human hair (available from barber shops and beauty salons) can be applied in mesh bags (1/8" mesh or less) and hung on outer tree branches at a height of approximately 30 inches. Each bag should contain at least 2 large handfuls of hair, and bags should be spaced at no further than 3 feet apart within the tree. Deoderant soap bars are also being used to repel deer. Soap bars are strung on wire and hung in trees in a distribution pattern as described for hair bags. Leave soap bar wrappers on to reduce weathering and prolong life. - 9 Rabbits Cottontail rabbits can be found throughout southern New England and often cause serious damage to young fruit trees. Damage to young fruit trees generally includes extensive bark removal and severe clipping of lateral shoots. Habitat control is an effective rabbit population control measure. Overgrown ditches, brushy fence rows or stone walls provide excellent food and protection from predators for rabbits. Elimination of these areas may be all that is needed for adequate rabbit control. Rabbit damage can be prevented by exclusion with hardware cloth (1/2 inch mesh) tree guards that extend 2 feet above the average snow depth. Orchard perimeter fencing or 1 or 1 1/2 inch mesh wire that extends 3 feet above the average snow depth is also effective. Taste repellents are another effective method of reducing rabbit damage to orchards. Repellents containing Thiram^ applied according to label directions have been effective. Other commercial products such as Hinder" also provide effective control. Orchard Mice and Voles^ Mice and voles are closely related rodents that can be distinguished from each other on the basis of tail and ear size, among other minor differences. In New England, mice are not a problem in orchards, but two species of voles frequently cause serious orchard damage. These pests are the meadow vole and the pine vole. Meadow voles range throughout New England, but pine voles are known to be present only in southern New England to southern Vermont, New Hampshire, and the southern tip of Maine (Kittery area) . Meadow voles inhabit the orchard floor, developing a network of surface trails through the groundcover, and they feed primarily on grasses and fleshy herbs. This species usually does most of its tree damage during the winter when herbage is less abundant, but damage is possible any time of the year. They chew away areas of bark and cambium that can be reached from the ground or from higher positions in or on snow cover. In some soils they will burrow, and sometimes are responsible for trunk girdling several inches below the ground surface. 'Information presented in this section taken in part from: - 1985 New England Apple Spray Guide - Cooperative Extension Services of New England - Management of Orchard Mice by Alan Eaton, Pest Management Fact Sheet #8, Cooperative Extension Service, University of New Hampshire - 1985. 10 Pine voles travel either in surface trails, or in burrows at depths up to 3 feet or more, depending somewhat on soil conditions. In solid grass sods they may be almost total ly subterranean, but where the ground cover contains a high percentage of broadleaf herbs, surface pine vole trails may be numerous. During the cold months, their activity is pretty much limited to the underground burrows. When herbage is abundant, pine voles put away caches in the tunnel system for later use. They feed upon bark and cambium primarily below the soil line, and chew off small roots up to about pencil diameter. Commercial apple cultivars and their seedlings, as well as the available rootstocks, are very susceptible to vole feeding. A selection of Mai us sublobata has been found to be quite resistant, however. The selec- tion was named "Novole" and has been introduced as an apple root and trunk stock for areas with severe vole problems. As a rootstock, "Novole" pro- duces a large, vigorous tree. Use of a dwarfing interstem is suggested for tree size control . Identification of Pest Species It is important to determine whether pine voles are present, because some of the management practices used for meadow vole are not effective against pine vole. Identification of the species may require trapping. Use snap traps baited with breakfast rolled oats, or peanut butter, or a 50:50 mix of these two. Fresh apple pieces are also a good bait. Place traps across active runs, including those that lead into underground burrows, if present. Cover the trap with an apple box, or similar cover to exclude birds and cats, and to aid in locating the trap trees in the orchard. Set enough traps to be sure of catching 5-10 voles, from various locations in the orchard. Check the traps after only one or two days. Tail length is useful for identification. The pine vole tail is very short; about the same length as the hind foot (not leg!), measuring 2>/k inch or less. The meadow vole tail is about twice the length of its hind feet reaching 1 1/2 - 1 3/^ inch on adults. Both species have chunky bodies, small beady eyes, and their ears are small and almost concealed in fur. Fur color is dark brown or gray-brown. If you catch a long-tailed specimen, it is likely to be a white-footed mouse (Peromyscus ) . The Peromyscus ' tail is well over 2 inches long, and all underparts of this mouse are covered with white fur. It is reported to eat bark of young trees occasionally, but is generally con- sidered a non-pest species in orchards. Your traps may also catch a shrew, which is a beneficial small mammal, or a mole. Shrews can be identified by their long pointed snout and needle-pointed front teeth. Voles have chisel- shaped front teeth. Moles differ from all others in their front feet, which are very large, with prominent digging claws. Orchard Floor Management Prevention of vole population build-ups offers the most practical method of reducing tree injury. 1. Mow orchard floor sod frequently during the growing season. On soils where erosion is not a problem, clean cultivate young orchards. 11 2. Maintain a vegetation-free area within at least 3 feet of tree trunks. The use of herbicides may be necessary to accomplish thi s. 3. Eliminate brush and thick vegetative cover around orchard peri- meters. k. Completely remove all fruit drops from the orchard. Tree Guards Maintenance of proper tree guards is the most effective measure for preventing tree girdling by meadow voles, unless snow depth exceeds guard height. Voles tunnel through snow to any depth. Trunk guards do not pre- vent underground damage by pine voles. Galvanized hardware cloth is one of the best materials for tree guards. One-quarter-inch mesh in 24-inch width is preferred. The cloth is cut large enough to completely encircle the tree and allow enough room for 10 or more years of growth. The cloth is formed into a cylinder and the cut ends are used to fasten it together so that no gaps are left for the mice to gain entry. Two or 3 short pieces of wire may be necessary to secure the ends. The guards are embedded at least 2 inches into the soil to prevent the rodents from burrowing underneath. An annual check of guards is recom- mended, preferably before the ground freezes. Hardware cloth is difficult to work with, and installation is time-consuming. Several rigid, perforated polyethylene or plastic mesh products are being promoted for use as tree guards. Each is used in a way similar to that of galvanized hardware cloth to form a cylinder which is buried in the ground and is of large enough diameter to give free circulation to air and to allow for growth. They are easier to handle than wire guards, but some may be broken down by ultraviolet light and may have a limited life. Wrap-around plastic guards are readily available, cheap and easy to install but are not recommended unless they are removed each spring and put on again in the fall. Various borers seem to prefer trees with wrap-around plastic or paper guards, and with their use the bark remains tender and har- dens off slowly. The plastic may become brittle when weathered, and these guards are difficult to keep in place on trees with uneven trunks or swollen graft unions. Paper wrap-around guards are not recommended. They must be tied off with string which can girdle the tree unless it is removed in the spring. Very high populations of bark borers have been found in trees protected with this material. The treated paper also weathers quickly, and the protected bark remains tender and hardens off slowly. Rodent ic ides Poison baits are of two types: zinc phosphide and anti-coagulant. Just one or two fresh grains or pellets of zinc phosphide baits can quickly kill the vole that eats them, but it may take several days of feeding on - 12 - anti-coagulant baits to kill voles. Owing to the catching habit of pine voles, poison baits that are taken by the species may not be consumed until much later, or not at all. Zinc phosphide breaks down slowly in moist air, and it loses its toxicity rather quickly if the bait becomes wet. To pre- serve toxicity of unused zinc phosphide baits, place opened package within a plastic bag and seal tightly. Rodenticide Techniques Broadcast applications of baits can be effective against meadow voles. However, they are usually not effective against pine vole. Bait should be directed into live ground cover where meadow voles forage, rather than into herbicide-treated strips. Most product labels limit treatments to the postharvest dormant period. The presence of dropped apples can make baiting ineffective, however, as farm apples are a preferred food for voles. All sound drops should be removed before bait is broadcast. If the weather is wet and dark during the first few days after bait is broadcast, the baiting effort will have been wasted. Wet weather and dark days discourage vole activity, and wet bait loses potency and palatabi 1 i ty . Try to bait just before a mild, fair-weather period of several days. Baiting in Artificial Trails. Mechanical trai 1 -bui Ider baiting machines construct trails beneath the soil surface, and supply baits at regular intervals for meadow or pine voles that enter those trails. According to the U.S. Fish and Wildlife Service, who can furnish plans to construct the device, this technique can be effective against both pine and meadow voles. Sod cover and reasonably moist soil is required at the time the machine is pulled through the orchard. Generally, one trail is made along each side of tree rows, beyond the wheel tracks, beneath the drip line of the trees, in sod. Trails should be cut 2-4 inches deep, with bait placed at ^4-5 foot intervals. Hand-bai ting. Hand-baiting implies selective placement of baits where vole activity is most likely, or where active trails or burrows are located. Teaspoon quantities of bait are placed, at the rate of 2-3 lbs. per acre. To greatly speed bait placement, bait stations such as asphalt roofing shingles or split tires should be distributed beneath the trees in sodded areas well in advance of baiting time. Over a period of weeks or months, voles develop trails under these bait stations; trails that can be quickly baited after harvest. Orchard Floor Sprays. Liquid Rozol" (chlorphacinone) is an anti- coagulant formulated for spray application. Effectiveness depends on thoroughly wetting and penetrating the ground cover. Before application, the ground cover should be dry and mowed short enough for maximum spray penetration. Voles are killed after repeated exposure to residues on the ground and cover crop. It will not be effective when there is no surface- feeding activity. 13 - Estimating Vole Activity Vole activity can be estimated by placement of apples in runways, or tunnel entrances. Place whole, firm apples, with a thin slice removed, at regular intervals throughout the orchard where activity is suspected. After 2k hours, lool< for small teeth marl I UPDATE ON DISEASE-RESISTANT APPLES ' William J. Manning and Daniel R. Cooley Department of Plant Pathology University of Massachusetts The first disease-resistant apple trees at the Horticultural Research Center in Belchertown were planted in 1978. Since that time, we have added other new cultivars and numbered accessions as they have become available. Descriptions and performances for some cultivars have been published in pre- vious FRUIT NOTES issues (Vol. hS, No. 1; Vol. ^9, No. 2). Our purpose here is to bring you up-to-date on the current contents of the collection and to make you aware of plans to evaluate a new block of disease-resistant apple trees to be established in a commercial orchard. There are now }k cultivars or numbered accessions in the collection at Belchertown (Table 1). All of them are immune or highly resistant to apple scab (Ventur ia inaequal is), but vary in their degree of resistance to black rot (Physalospora obtusa) , cedar-apple rust ( Gymnosporang i urn jun iper i - viginianae) , and powdery mildew (Podosphaera leucotr icha) . Their reactions are compared to those of the disease-susceptible cultivar, Imperial Mcintosh. Foliar and fruit evaluations were made on September 10, 1985- One-hundred leaves were evaluated per tree for percent incidence of black rot, rust, and scab (Table 2). Foliar black rot was especially evident on Imperial Mcintosh, King Luscious, MacFree, Nova Easygro, and Sir Prize. Rust was evident on Imperial Mcintosh, King Luscious, and Sir Prize. Scab was evident only on Imperial Mcintosh. These findings were consistent with previous results. 19 Table 1. Disease-resistant apples at the Horticultural Research Center, Belchertown, MA. Cul t i var Year Planted Source Imperial Mcintosh Liberty MacFree Nova Easygro NY 613^5-2 Pr i sc i 1 la Sir Pr ize King Luscious Jonaf ree Redf ree Freedom Sweet Sixteen NY ys^i^^-i NY 66325-113 NY 7^828-12 1978 1978 1978 1978 1978 1978 1978 1983 1983 1983 1984 1984 1985 1985 1985 Kel ly Bros. Geneva Program Canadian program Canadian program Geneva program PRI program^ PRI program Bountiful Ridge PRI program PRI program Geneva program Univ. Minnesota Geneva program Geneva program Geneva program -Purdue, Rutgers, Illinois cooperative program Table 2. Performance of disease-resistant apple trees in 1985.^ % Fol iar diseasesY % Fl Frui t di y speck i seases^ Cult i var Black rot Rust Scab Scab Freedom 0.5 0 0 NAW NA Imperial Mcintosh 20 60 76 10 100 Jonaf ree 5 10 0 NA NA King Luscious 25 30 0 NA NA Liberty 5 0 0 2 0 MacFree 15 10 0 10 0 Nova Easygro ^ 20 0 0 5 0 NY 61345-2 10 0.5 0 2 0 NY 75414-1 5 0 0 NA NA NY 66325-113 5 0 0 NA NA NY 74828-12 10 0 0 NA NA Prisci 1 la 10 6 0 0 Redfree 10 0 0 NA NA Sir Prize 40 20 0 0 0 Sweet Sixteen 5 0 0 NA NA ^Evaluations made on 10 September 1985. ^100 leaves evaluated/tree. ^Percent of available fruit (variable for cultivars and accessions because of tree age) . ^NA = Not applicable, no fruit. 20 During the 1985 season, the grass in the block was longer than usual. For the first time we noted a low incidence of fly specl< (Zygophiala jamaicensi s) on Imperial Mcintosh, Liberty, MacFree, and NY 613^5-2. While not a serious problem, flyspeck infections can reduce grade. Better manage- ment of grass heights will help to eliminate this problem. Evaluation of disease-resistant apple trees allows us to see how they perform under Massachusetts conditions. We now are ready, however, to establish a block of di sease-res i-stant trees in a commercial orchard. This will be done in the spring of 1986 in western Massachusetts with a cooperating grower and through the Regional Extension Agent, Karen Hauschild. As the trees grow and bear, they will be evaluated for perfor- mance by a plant pathologist, entomologist, and pomologist. The grower will also make critical evaluation as will other growers who see them at educa- tional meetings held at the orchard. The test block will consist of 16 trees each of Rogers Mcintosh, Liberty, Freedom, Redfree, PRI Coop No. 23, NY 7^*828-12, and NY 75^'i^-^, for a total of 112 trees all on M7A. Developing disease-resistant apple cultivars is a long and tedious pro- cedure. The cultivars that are emerging are, however, improving all the time. The two NY numbered accessions planned for the commercial orchard trial were selected because they have many of the characteristics of Mcintosh, yet are immune to scab and highly resistant to other apple diseases. Better cultivars and insect management strategies aimed at reducing sprays will result in quality apples available for direct sale to consumers with the assurance that only a very few insecticide applications were made. Ron Prokopy, University of Massachusetts Department of Entomology, has demonstrated that he can use as few as two insecticide sprays on his disease resistant apples and still produce a crop of nearly blemish-free apples (Fruit Notes 50(2):2-5). All of the trees in the Disease Resistance Block will be labelled by name. Please feel free to examine them when you visit the Horticultural Research Center. For additional information on disease-resistant apple trees, please contact Dr. William J. Manning in the Department of Plant Pathology. Acknowl edgements; We thank Tony Rossi and others at the Horticultural Research Center for maintaining the block and applying insecticides. Special thanks go to the Horticultural Research Center Trust Fund for purchasing trees of 5 of the 7 apple cultivars to be used in the commercial orchard planting and to Hilltop Nurseries for donating Redfree and PRI Coop Trees. This activity is also supported by the University of Massachusetts Cooperative Extension Service. - 21 - PEACH ROOTSTOCKS IN NEW JERSEY by Jerome L. Frecon Cooperative Extension Service Cook Col iege--Rutgers University We recommend that growers have peach and nectarine varieties budded on Lovel 1 and Halford seedling rootstocks for future peach plantings. We also recommend that the seedlings used in the production of these rootstocks be from seed collected in self-pollinated seed orchards. Seeds produced in cross-pollinated orchards may have great variability and result in short- lived trees. We also encourage growers to purchase trees on virus-certified seedl ings. Some growers have been planting peach trees on seedlings of Tennessee Natural and Bailey. We do not have enough research information in New Jersery or the Eastern United States to make a recommendation on their per- formance. Bailey, which is being tested in our NC-140 planting at the Rutgers Fruit Research and Development Center in Cream Ridge, New Jersey, was found in Iowa and has been planted by some growers in the Midwest and Canada. It is reported to impart cold hardiness and vigor to the scion variety by Midwestern and Canadian growers and researchers. Tennessee Natural is a broad name given to seeds collected from wild peach trees in the mountains of Tennessee and Kentucky. Seeds are not available from these sources. Some growers and nurserymen feel these old time trees are longer lived and hardier than today's trees. In the past 20 years some selections of Tennessee Natural were made, virus indexed and established at the Interregional Fruit Repository at Prosser, Washington. Some nurserymen have collected scionwood from these selections, budded seed trees and established seed orchards for tree propagation. Based on the current short tree life of peach orchards in New Jersey, growers probably have little to lose by trying a test planting of trees on these stocks. Lovel 1 and Halford originated in California and can be improved upon for tree hardiness. The dwarfing rootstock, Citation, has been tested in Gloucester County since 1982. It reduces tree size over S0% on peaches and nectarines in comparison to Lovel l-rooted trees. It imparts early defoliation in the fall. Trees appear to be stressed and are suffering from slow decline on our loamy sand soils. We have numerous plantings of self-rooted peach trees and experimental plantings up to 5 years of age. Self-rooted trees are equal in performance to trees on Lovel I and Halford. Jerseyqueen on its own roots has been more precocious and productive than on Lovel I seedling. Jefferson has been 30% reduced in size on its own roots than on Lovel 1. Much more testing needs to be done. ***** 22 ROOTSTOCK EVALUATION IN MASSACHUSETTS (Editors note: Massachusetts is involved in a multistate apple rootstock evaluation project (NC-140). Two groups of rootstocks are being evaluated at the Horticultural Research Center in Belchertown, Massachusetts along with approximately 30 other locations in the U.S. and Canada. The first group was planted in I98O and the second was planted in 1984. The descriptions presented here were supplied by Dr. David Ferree, Ohio State University, and a later Frui t Notes article will discuss observations in Massachusetts. ) Rootstocks in I98O NC-TtO Planting 1. Ottawa 3 - Originated as a cross of Robin x M.9. (Robin is a hardy crabapple). It produces trees of M.9 size or slightly larger, but better anchored than M.9. It is reported to be resistant to crown rot, but susceptible to fireblight and to wooly aphids. Suckering is rare. 2. EMLA 7 - This is the original M.7 with known viruses removed. According to early reports, it produces a tree only slightly larger than the original M.7, which would be 50 to 60^ the size of standard. 3. EMLA 9 - In providing this stock with EMLA virus status, apparently a sub-clone was selected and trees on the EMLA 9 may be 25-50^ larger than the original M.9. It is reported to result in less russet on Golden Delicious and have greater productive efficiency than M.9. 4. EMLA 26 - Early reports indicate only a slightly larger tree than the original M.26. 5. EMLA 27 - This stock has not been widely tested, but produces a tree smaller than M.9 (15-20^ the size of standard), is very precocious, not well anchored, and generally free of root suckers. Originally it was produced from a cross of M.13 x M.9. Northern Spy and Granny Smith have shown some incompatibility (broken off union) with EMLA 27. Compared to M.9, M.27 is similarly resistant to crown rot and susceptible to fire blight and wooly aphid. Its hardiness is unknown. 6. M.9 - This rootstock produces trees 20-35% the size of standard trees, is very precocious and fruitful, and poorly anchored with a tendency to sucker. It has a long history in both the U.S. and Europe and is used as the standard in this trial. 7. MAC 9 (MARK) - Introduced in I98O by Michigan State University. Dr. Robert Carlson selected it as an open-pollinated seedling of M.9. It produces trees about the same size as M.9 or slightly larger, is very precocious and fruitful, and is non-suckering. - 23 - 8. MAC 2k - Another selection in the Michigan Apple Clone series (Female parent was Robusta 5). Trees on this rootstock are vigorous in the MM. Ill or Standard size class. It has a shallow spreading rootsystem and is well anchored. It has not been widely tested. 9. OAR 1 - An Oregon planting of Gravenstein on seedling rootstocks made in 19^3 had many trees blown over by a severe storm in 1962. Among the survivors was a conspicuously dwarfed tree that was very productive. Suckers of this tree were propagated by Dr. Melvin Westwood of Oregon State. This stock has not been widely tested. Apple Rootstocks in 1984 NC-140 Planting 1. Bud 491 - One of the hardy Budagovsky rootstock series produced at the Michurin College of Horticulture in Russia. B. 491 produces trees smaller than M.9, is very winter hardy, and propagates well. 2. B.9 - One of the Budagovsky series (Red-leafed Paradise) with dwarfing potential similar to that of M.9. New York tests indicate suscep- tibility to fire blight, wooly aphids, and brittle roots. It is much hardier than M.9 and has greater resistance to crown rot. 3. MAC 1 - One of the Michigan Apple Clone series originated by Dr. Robert Carlson from an open-pollinated planting of the Mailing rootstocks (Female parent Ml). Trees on this stock are approximately M.7 size, but do not sucker and are well anchored. 4. MAC 39 - One of the Michigan Apple Clone series producing trees smaller than M.9 and very precocious. Trees on this stock are not well anchored. 5. P.I - One of the Polish series produced at the Research Institute of Pomology and Floriculture at Sk ierni ewicz . This series was produced from a cross of Antonovka. P.l produces trees similar in size and pro- ductivity to M.9, but are easier to propagate and have greater winter hardi ness. 6. P. 11 - Another of the hardy Polish series producing trees smaller than M.9 with s imi lar propagat ion characteristics. 7. Domestic Seedling - The full size standard in this trial. Seedling stocks generally produce large vigorous trees with late-bearing ten- dency, but good soil adaptability and anchorage. 8. CG 10 - The Cornell-Geneva (CG) series of rootstocks was originated by Karl Brase CG-10 (M.8 open pollinated) produces trees slightly larger than M.9 with good anchorage and some tendency to sucker. It has moderate resistance to collar rot and fire blight. 9. CG 24 - Its parentage was open-pollinated M.8, and it produces trees approximately M.26 size. - 2k - 10. M.4 - One of the original Mailing series producing trees similar in size, precocity, and suckering to trees on M.7. One of the major problems of M.^ is that roots tend to develop mainly on one side, making anchorage questionable. There is renewed interest in this stock because of its resistance to collar rot. 11. EMLA 7 - One of the semi-dwarfing standards in this trial. 12. EMLA 26 - One of the dwarfing standards in the trial. 13. B. 'tSO - Another of the Budgovsky series producing trees similar in size to MM. 106. It induces early production, burr knots rarely occur, and it is easy to propagate from hardwood cuttings. It is crown rot resistant and moderately susceptible to fire blight and susceptible to wooly aphid. 1A. P. 2 - One of the hardy Polish series producing trees larger than M.9 and smaller than MM. 106 with productive efficiency good, but slightly lower than that of M.9. It has good resistance to crown rot. 15. P. 16 - One of the Polish series producing trees of M.9 size with similar winter hardiness and productive efficiency but with superior propaga- tion characteristics. 16. P.l8 - One of the Polish series that resulted from a cross of M.4 x Antonovka and produces a tree size similar to that of MM. 106. It shows less susceptibility to fireblight than the other P series rootstocks, combined with good resistance to crown rot. 17. Own Rooted - These stocks were produced through tissue culture by Oregon Rootstock and Stark Brothers Nursery so that we could test tree performance and size of Starkspur Supreme Delicious without a geneti- cally different rootstock. 18. C.6 - Originated as a dwarfing interstem by Stark's from open polli- nated M.S. It reportedly produces trees the size of M.26 and is very susceptible to fire blight. 19. Antonovka 313 - From the Adams Nursery in Washington State as selec- tions from open-pollinated Antonovka from Poland, This selection appears resistant to crown rot. 20. 0.3 - Originated as a cross of Robin x M.9. (Robin is a hardy crab-apple.) It produces trees of M.9 size or slightly larger, but they are better anchored than M.9 trees. It is reported to be resistant to crown rot, but susceptible to fire blight and to wooly aphids. Suckering is rare. 21. AL 800 - Produced from suckers of a dwarfed Duchess tree on seedling rootstock in the Arnold Lynd orchard in Ohio. The original tree did not show winter injury symptoms after the 1936 freeze or the collar rot experienced by trees on MM.IO6 in surrounding blocks. This rootstock has not been tested and demonstrates difficulty in propagation by con- ventional methods. ***** - 25 - CULTIVARS OF APPLES FOR MASSACHUSETTS James F. Anderson Department of Plant and Soil Sciences University of Massachussetts Cultivar Recommended for Harvesting season Vista Bel la Jerseymac Paulared Akane Jonamac Gala Mel ntosh Macoun Empire Cortland Del ic ious Golden Del icious Idared Spencer Mutsu C T C T T T C C C C C C c c c Late July to early August Mid to late August Late August to early September Early September Early to mid September Mid September Mid September Late September Late September Early October Early to mid October Mid October Mid October Mid October Mid October T = Trial C = Commercial Cultivars so marked are not necessarily equally adapted to al 1 parts of the state. Cultivar Notes VISTA BELLA: The fruits are of medium size, firm, have a bright, smooth finish, medium red color, and very good quality for an apple of this season. Susceptible to watercore. The tree is large, vigorous, and productive. JERSEYMAC: An attractive Mcintosh type. The fruit is above medium in size, with a bright red color over about 8Q% of the surface. The texture is medium in firmness and the quality good. The tree bears early and is pro- ductive. Thinning may be necessary to maintain size and annual production. PAULARED: Ripening in late August, the fruits are medium to large in size, roundi ng-oblate in shape, and have excellent color and finish. The fruit colors very early and is often picked before optimum size and quality are reached. The trees are annual and productive. AKANE: The fruits are medium in size, attractive with a bright red color, but may show some russet. The flavor and keeping qualities are very good. The trees in our plantings have been less than moderate in production. JONAMAC: A Mel ntosh-type apple, ripening about a week before Mcintosh. The fruits are of meidum size, firm, crisp, and have very good quality. The fruit develop a good red blush color. The tree is medium in vigor and appears to be productive. Merits trial by growers operating farm markets or servicing retail stores. - 26 - GALA: This introduction from New Zealand has looked very promising in our trials. The fruit ripens in mid-September, is medium to large in size, and round-conic in shape. The flesh is yellow, crisp, and very good in flavor. The skin is smooth, and its golden-yellow color is overlaid with about 80% red. The trees have been annual and productive. Gala merits trial by those growers operating farm markets or servicing retail stores. Red strains are aval lable. MCINTOSH: Remains the major cultivar for Massachusetts. The fruit is attractive, has excellent quality, but bruises easily. The tree is vigorous, hardy, and productive. Red strains such as Marshall, Imperial, Rogers, or Summerland are preferred. Spur types are available. MACOUN: The fruit has excellent quality and an attractive red color. The tree tends to develop a poor structure, and thinning is required to maintain fruit size and annual bearing. Macoun is an excellent cultivar for the farm market. EMPIRE: A very attractive apple with full red color, medium size, very good dessert quality, and good storage life. The tree is annual and productive. The flowers of Empire are susceptible to frost. CORTLAND: The fruit is large, very good in quality and excellent for salads, as the flesh does not discolor. Cortland fruit are very susceptible to storage scald. The tree is hardy, productive, and annual. Redcort, a recently introduced red strain of Cortland, merits trial. The fruits of Redcort develop a dark red color that covers most of the fruit. (See article on p. 1 this issue). DELICIOUS: Produces fruit of excellent quality but susceptible to watercore and internal breakdown. Tree is of medium vigor, often biennial, and may require thinning. A good pollinizer, Redchief, Starkrimson, and Sturdeespur are good spur types. imperial and Early Red One are among the better non-spur types. GOLDEN DELICIOUS: The fruit is of excellent quality and attractive when well grown. The fruit is susceptible to russeting. Tree is of medium vigor, biennial and requires thinning to maintain fruit size, color, and quality. Russet-free strains such as Smoothee are recommended. IDARED: An attractive bright red winter apple of good quality and size. Suitable for both dessert and processing. The tree is small, annual, and productive. SPENCER: The fruit is attractive, bright red, and has very good quality suitable for both dessert and pie. The tree is hardy, annual, and produc- tive. Spencer is most useful for the farm market. MUTSU: A Golden Delicious type that is less susceptible to fruit russeting and storage shrivel. The tree is vigorous and productive. Mutsu is a triploid and its pollen is not viable. The fruit is susceptible to blister spot. ***** 3982' 061 COOPERATIVF EXTENSION SERVICE U S DEPARTMENT OF AGRICULTURE UNIVERSITY OF MASSACHUSETTS AMHERST MASS 01003 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE. S300 BULK RATE POSTAGE & FEES PAID USDA PERMIT No G268 ACME BOOKBINDING CO.. INC. JUL 1 6 1987 100 CAMBRIDGE STREET CHAnlLESTOWN. MASS.