B\CLO' •fti D a D D a a a D a a D n D D a a a a D D D a a D o D □ a D a □ D □ D □ n a D D JUUUUUUU _ ftuG mi DDDnnonnannnanDnDDonnnnnnDna D a D D D □ D D SCIENCES S.IBHARY UNIVERSITY OF MASSACHUSETTS LIBRARY n a a a D D a a a D D D D D D D D D D D D D D D O D D a n D D D D D D D D D D DDDDDnDaaDDDaDDDDDUDDDDannna FRUIT p,- NOTES PREPARED BY DEPARTMENT OF PLANT AND SOIL SCIENCES COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF MASSACHUSETTS, UNITED STATES DEPARTMENT OF AGRICULTURE AND COUNTY EXTENSION SERVICES COOPERATING. EDITORS W. J. LORD AND W. J. BRAMLAGE Vol. 48 No. 1 WINTER ISSUE, 1983 Table of Contents FRUIT NOTES Subscription Varieties of Grapes for Massachusetts Varieties of Peaches for Massachusetts Performance of Disease Resistant Apples in Massachusetts Disease Management for Apples in Massachusetts: 1982 Results and Summary of the Five-Year Program Factors Affecting Nutrient Content of the Foliage and Fruits of Apple Trees Pomological Notes Integrated Management of Apple Pests in Massachusetts, 1982 Results: Insects Issued by the Cooperative Extension Service, Daniel I. Padberg, Director, in furtherance of the Acts of May 8 and June 30, 1 91 4; United States Department of Agriculture and County Extension Services cooperating. The Cooperative Extension Service offers equal opportunity in programs and employment. The cost of publishing FRUIT NOTES has become a significant portion of the Smith-Lever allocation for my extension program. If we continue to send it free- of - charge very little money will be left for travel, attendance at meetings, and supplies. Thus, starting with the Spring Issue, FRUIT NOTES will be on a subscription basis at $3.00 per year for 4 issues. Hereafter, the subscription year will commence with the Winter Issue. A notice for renewing your subscription will appear in the fall issue of the previous year. To subscribe to FRUIT NOTES, complete and mail the following form with your check for $3.00. William J. Lord William J. Bramlage Editors, FRUIT NOTES WJL/pm Name Mailing address Town, State, Country zip Make checks payable to: FRUIT NOTES ACTIVITY ACCOUNT Send subscription form and check to: William J. Lord Department of Plant and Soil Sciences French Hall University of Massachusetts Amherst, MA 01003 VARIETIES OF GRAPES FOR MASSACHUSETTS James F. Anderson Department of Plant and Soil Sciences The following is a list of varieties that are currently recommended for planting in Massachusetts. Many new seeded and seedless varieties have been introduced in recent years. Some of these may be equal to or better than the one listed. Those growers interested in grapes for wine should obtain a copy of the Catalog of New and Notev\forthy Fruits from the New York State Fruit Testing Cooperative Association, Inc., Geneva, NY 14456. This catalog offers a description of the French-hybrid and other varieties suitable for wine production. Variety Recommended for Harvest Season Schuyler Himrod Van Buren Ontario Seneca Suffolk Red Fredonia Buffalo Delaware Lakemont Worden Blue Boy (Cook) Niagara Concord Steuben T = Trial T H C& H H H T C& H H C&H T C&H C&H C&H C&H T H = Home garden late-August late August— early September late August— early September late August— early September late August— early September late August— early September early September early September mid-September mid-September mid-September mid-September late-September late-September late-September C = Commercial All varieties are not necessarily equally adapted to all sections of the state. Late ripening varieties are recommended only for those areas with a sufficiently long growing season to permit satisfactory ripening of the fruit. Variety Notes Schuyler — A very early, high-quality, black grape. The clusters are medium to large and moderately compact. The berries are medium in size, tender, and juicy. The vine is vigorous, productive, and medium in hardiness. Schuyler require severe pruning to prevent overbearing. Himrod — An early-ripening, seedless grape resulting from a cross between Ontario and Thompson Seedless. Its clusters are large and rather loose. The berries are medium, oval, sweet, yellow, vinous, and good. The vine is not completely winter-hardy under our conditions and should be restricted to the more favored sites. Van Buren - An attractive, black grape of good to excellent quality. The vine is vigorous and productive. It is particu- larly susceptible to downy mildew. An early-ripening, white grape of high quality. The plust^rs are medium in size and tend to be loose. The berries tend to shatter considerably within a few days after harvest. The vines are medium in vigor and productivity, and are hardy. An early-ripening, white grape with a thin, tender, adherent skin. The berries are medium in size, oval, and have excellent flavor. The clusters are medium in size and compactness. Seneca is susceptible to win- ter injury. Suffolk Red - A bright-red, seedless grape. The clusters are medium in size and tend to be loose. The berries are medium in size, round, and have very good quality. The vine is medium in hardiness. Ontario — Seneca Fredonia — A good-quality, black grape especially recommended for the roadside stand trade. The clusters are com- pact and medium in size. The vine is vigorous, hardy, and productive. It should be pruned less severely than Concord. Buffalo — A black grape with medium to large size, sweet, vinous flavor and good adherence. The clusters are large and tend to be loose. The vine is vigorous and productive, and the fruit holds very well in storage. Buffalo tends to overbear and to be susceptible to winter injury if not properly pruned. Lakemont — A yellowish-green, seedless grape. Its clusters are medium to large and moderately compact. The berries are medium to small in size, oval, tender, juicy, and sweet. The vine has moderate vigor and hardiness. Tends to overbear. Delaware — A high-quality, red grape with small clusters and berries. The vines are hardy and are moderate in vigor and production. Delaware would add to the attractiveness of displays on a roadside stand. Worden — Similar to Concord, but ripens a week to ten days earlier. While slightly superior to Concord in quality and attractiveness, it has a tendency to crack when ripe and shatters badly within a few days after it is harvested. A desirable variety for local trade and the home vineyard. Blue Boy — This is an attractive, black grape with an abundance of bluish bloom. Adherence of the berries is good and (Cook) the quality is excellent. Vines are productive and the fruit holds in storage unusually well. Recommended for commercial planting and is a desirable variety for the home vineyard. Niagara — A white grape of high quality with large compact clusters. Would add to attractiveness of display on a roadside stand. Ripens with Concord. Concord — The particular merits of Concord are its adaptability to a wide variety of soils, its productiveness, hardi- ness, vigor, and shipping quality. Concord requires a growing season of approximately 160 days for proper ripening of its crop. Steuben — Those growers who can mature Concord might wish to try this variety. The grapes are bluish-black in color, medium in size, and have very good quality. The clusters are medium to large, compact, and attrac- tive. The vines are usually hardy, vigorous, and productive. ■A ********* Variety ■ A- VAR urn lis 0|- PHACIIHS for MASSACimSr.TTS .James F. Anderson nepartmcnt of Plant and Soil Sciences Recommended for 2 Flesh color Approximate harvest date 3 Harbinger Candor Garnet Beauty Sweethaven Brighton Harbelle Reliance Raritan Rose Redhaven Harken Harbrite Velvet Jayhaven Glohaven Eden Richhaven Canadian Harmony Cresthaven Jerseyglo Autumnglo C — Commercial 1 C Y T Y C Y T Y T" Y C Y H Y C W C Y C Y C Y C Y T Y C Y T W C Y C Y C Y T Y T Y H — Home garden -30 -20 -13 -13 -13 -8 -4 -2 0 +3 +5 +7 +7 +10 +11 +12 +16 +21 +26 +30 T - Trial All varieties are not necessarily equally adapted to all sections of the state. 2 V - Yellow flesh W - White flesh Based on harvest date for Redhaven (approximately August 20, but can vary from location to location and season to season). Minus sign indicates number of days before; plus sign indicates number of days after Redhaven. Harbinger — Candor* — Garnet Beauty — Sweethaven* — Variety Notes An attractive, small to medium-sized clingstone peach. The flesh is yellow, firm, melting, and has very good flavor for this season. The tree is vigorous, productive, and equal to Redhaven in bud hardiness. The fruits are well-colored, and small to medium in size. The flesh is yellow, firm, and juicy and the stone is semi-cling. The buds are hardy and the tree vigorous and productive. A bud-sport of Redhaven. Resembles Redhaven in color and texture. It is a semi-clingstone. The tree is vigorous, productive, and hardy. An early, yellow-fleshed, semi-clingstone peach. The fruits are medium in size, roundish, and well colored. The flesh is juicy, slightly fibrous, but soft. The tree is vigorous, productive, and similar to Redhaven in bud hardiness. Brighton* — Harbelle — Reliance — Raritan Rose — Redhaven — Harken — Harbrite — Velvet - Jayhaven* — Glohaven — Eden* - Richhaven — Canadian Harmony Cresthaven* — Jerseyglo* — Autumnglo* — An attractive, high-quality, yellow-fleshed peach. The fruit is roundish, uniformly medium in size, and highly colored. The flesh is medium firm, juicy, with very good flavor. The pit is semi- cling. The tree is vigorous, productive, and medium-hardy. The fruit is large, attractive, with deep-yellow ground color and a bright-red blush. Flesh is a rich yellow, medium in firmness, of good quality. The stone is semi-free. The tree is productive, and medium in vigor and bud hardiness. A medium-sized, roundish, yellow-fleshed freestone peach of fair to good flavor. Reliance is recommended as a very hardy variety for the home fruit planting. The fruit is large, round, attractive. The flesh is white, firm and juicy. The tree is large, upright- spreading, and productive. Bud hardiness is above average. The medium-sized fruit is highly colored, attractive, and has firm flesh and fair flavor. The tree is very productive and requires heavy thinning. A large attractive, yellow-fleshed peach. The flesh is firm, juicy, of good quality and the stone is free. The tree is vigorous, productive, and equal to Redhaven in bud hardiness. A large, attractive, yellow-fleshed peach. The flesh is medium-firm, juicy, and of good flavor. The stone is free. The tree is very productive, hardy and moderately vigorous. A medium-to-large, attractive, freestone peach. The flesh is yellow, firm, juicy, and has very good flavor. The tree is moderately bud hardy. A medium-large, round, bright-colored freestone. The flesh is yellow and melting. The tree is more bud hardy than Glohaven. A large, roundish, mostly red peach with very little fuzz. The flesh is yellow, very firm, and has very good flavor. The stone is free. The tree is medium in bud hardiness, but is vigorous and pro- ductive. The fruit is large, roundish, with 60 percent red on a creamy white ground color. The white flesh is thick, firm, juicy, smooth, and very good in flavor. The stone is free. The tree is vigorous, equal to Redhaven in bud hardiness, and very productive. A large, attractive, highly-colored freestone of very good quality. The tree is large, vigorous, and productive. Bud hardiness is above average. A large, highly-colored, yellow-fleshed peach. The flesh is firm, juicy and of good flavor. The tree is vigorous, productive, and about equal to Redhaven in bud hardiness. A large, oblate-shaped peach with a dark-red blush. The bright yellow flesh is firm, juicy and slightly fibrous. There is some red at the pit. The flavor is very good. The tree is vigorous, pro- ductive, and medium in hardiness. The fruits are large, attractive, and freestone. The flesh is yellow and firm. The trees are vigorous and productive, and about equal to Redhaven in bud hardiness. A large, round, highly-colored freestone. The flesh is yellow, firm, and melting. The trees are vigorous, productive, and are equal to Redhaven in bud hardiness. A A A ft A A A A A A ■6- PERFORMANCE OF DISEASE RESISTANT APPLES IN MASSACHUSETTS Christopher M. Beckerl Daniel R. Cooley, and William J. Manning3 Department of Plant Pathology, University of Massachusetts, Amherst A number of apple cultivars, with immunity to apple scab, and varying degrees of resistance to rusts, powdery mildew and fireblight, are currently available from commercial nurseries. As these cultivars have potential use in apple disease management programs, designed to reduce fungicide usage, we established a block of disease resistant apple cultivars at the Horticultural Research Center in the spring of 1978 to determine their performance in Mass- achusetts. Fruit were harvested in 1982 for the first time. Eight cultivars were planted. Prima, Priscilla, and Sir Prize were developed by the Purdue, Rutgers, and Illinois (PRI) Agricultural Experiment Station co- operative apple breeding program. MacFree and Nova Easy-gro were developed in Canada and Liberty and NY61345-2 by the New York Agricultural Experiment Station. Disease-susceptible Imperial Mcintosh was used for comparisons. Trees were obtained from either the New York State Fruit Testing Cooperative or Stark Bros. Nurseries. Cultivars used have been described by their developers as follows: Prima: 2-1/2 to 3". 60-80% bright red, over yellow ground color. Rich flavor and crisp texture, with mild subacid flavor. Flesh, light cream color. Little tendency for fruit to drop before harvest. Fruit matures 1 month before Red Delicious, and will retain its flavor for up to 1 month at 34 F. Trees are spreading and vigorous. Immune to apple scab, susceptible to cedar apple rust, slightly susceptible to powdery mildew, and resistant to fire blight. Excellent dessert apple. Priscilla: 2-1/2 to 3". 75-90% bright red, over yellow ground color.. Crisp texture and pleasant aromatic flavor. Texture and flavor maintained for 2-3 months at 34 F. 2 weeks before Delicious (10 days after Prima) . Little tendency for fruit drop before harvest. Trees are moderately spreading and vigorous: terminal growth frequently determinate, ending in a flower bud. Trees and fruit are immune to apple scab, and resistant to cedar apple rust, and fire blight. Fine dessert quality. Sir Prize: 3 to 3-1/2". Yellow, russet free. Ripens with Golden Delicious (4 weeks after Prima). Juicy flesh, fine grained texture with thin skir^ that is easily bruised with rough handling. Waxy skin does not shrivel in storage. Very good keeping quality through the winter season. Trees are vigorous, triploid and produce an annual crop. Immune to apple scab, moderately resistant to cedar apple rust and powdery mildew, trees have shown little fire blight. Excellent for home planting or use with direct sales or pick-your-own. 1 9 Disease Management Technician ^ Extension Technician 3 Professor of Plant Pathology Macfree: 2-3/4", 75% medium to dark lively red, slightly stripped, over greenish-yellow ground color. Juicy white flesh, sometimes tinged with green. Slightly course, tough texture, moderate acidity and firm; pleasant flavor. Ripens a few days before Red Delicious, Stores 3 months at 32 C. Vigorous spreading tree: fruit borne throughout. Resistant to apple scab. Nova Easy-gro : 2-1/2", blushed or stripped medium red over pale greenish- yellow ground color. Creamy white flesh, firm, crisp, moderately juicy, subacid; pleasant. Matures with Cortland, keeps well. Trees are moderately vigorous, and spreading, with fruit borne throughout the tree. Fruit resistant to apple scab. (Multigenic resistance from Russian seedling) . Liberty: 2-3/4", deep bright red, stripped on greenish-yellow ground color. (Mcintosh parentage easily recognizable.) Flesh pale yellow, nearly white; crisp, juicy, slightly coarse in texture. "Sprightly", subacid; browns rapidly upon exposure to air. Keeps well under refridgeration until January and stores very well as juice, cider and sauce. Trees are "precocious"; out- yielded Mcintosh and Red Delicious on similar topworked trees. Vigorous growth, round topped and spreading: very productive with fruitbuds terminally and laterally on shoots of current year's growth and spurs. Immune to apple scab and cedar apple rust; resistant to powdery mildew and fire blight. NY 61345-2: 2-7/8", 90% red blush. Crisp, juicy, slightly coarse; sprightly. Tree: vigorous and upright. 2 days before Red Delicious. Immune to apple scab, moderately resistant to cedar apple rust and powdery mildew. Standard insecticide sprays were applied from 1978-1982, but no fungicides were used. Natural inoculum for apple scab and cedar-apple rust was abundant in all years. In mid-September, 100 randomly-chosen leaves per tree were evaluated for per cent apple scab, cedar-apple rust, and frog-eye leaf spot (black rot). Fruit were evaluated at harvest for scab and other diseases. Results are summarized in Table 1. All of the disease resistant cultivars were completely free from fruit and foliar scab. Imperial Mcintosh, however, had 48.5% foliar and 28.3% fruit scab. While all the disease resistant cultivars had less foliar cedar-apple rust than Imperial Mcintosh, Macfree and Sir Prize had more foliar infection than Nova Easy-gro, NY 61345-1, Priscilla, and Liberty. The original Prima trees died before 1982. Several younger Prima trees were completely free from scab, but had extensive cedar-apple rust on leaves. One Prima fruit also had a rust infection spot. All cultivars had frog-eye leaf spot, with Sir Prize having the highest incidence. Frog-eye leaf spot on Sir Prize, however, consists primarily of small purplish flecks, rather than more typical symptoms. To determine fruit quality. Nova Easy-gro, Liberty, Macfree, NY 61345-2, and Imperial Mcintosh fruit were harvested and stored at 34 F. in a conventional cold storage. After one month of storage, fruit were removed, sliced, and offered to 29 randomly-chosen students, secretaries, faculty and technicians. Most tasters found little difference between Imperial Mcintosh, Macfree, and Nova Easy-gro. While all had similar textures Nova Easy-gro, and Macfree were judged to have slightly less flavor than Imperial Mcintosh. Wi 61345-2 was generally agreed to be a tasty and slightly tart apple. While not as firm as Imperial Mcintosh, NY 61345-2 was rated as the first choice of most tasters. Liberty compared well with Imperial Mcintosh, but was not as sweet and did not store as well. When tasters were shown nonlabelled fruit of all the cultivars, all comments were favorable. More than 80% of the tasters agreed that they would purchase the fruit if available in roadside stands or in supermarkets. In 1983, we will be adding the following new cultivars to our planting: Redfree: Redfree is a medium size (2-3/4") apple with 90% good red color and smooth, waxy, russet-free skin. Flesh is white, crisp and juicy. Retains quality for two months or more in storage. Fruit ripens 3 weeks before Prima and 7 weeks before Delicious. Immune to scab and cedar rust, moderately resistant to fire blight and mildew. Jonaf ree: Closely resembles and matures with Jonathan. Fruits are 2-1/2 to 2-3/4", 75% medium red, with a smooth russet-free skin. Flesh is pale, crisp, and juicy. Immune to scab and resistant to fire blight and cedar-apple rust. Moderately susceptible to mildew. Fruit hangs well to maturity and do not develop Jonathan spot. King Luscious: A very large, highly-colored apple with good keeping, eating and cooking qualities. The skin is a deep red with a beautiful bloom. The flesh is pure white, with excellent flavor. Season of ripening is with Rome Beauty and Stayman, although it may be picked sooner for cooking purposes. The tree is a young and annual bearer, blooming a week after Rome Beauty, to make it almost completely frost-proof. The tree is semi- dwarf in habit, sets it scaffold branches well, and needs little pruning. Both tree and fruit are resistant to apple scab. U.S. Plant Patent No, 1994. Redfree and Jonaf ree are being obtained from Hilltop Nurseries. King Luscious will come from Bountiful Ridge Nurseries. All of the trees in the Disease Resistance block will be labelled this spring by name. Please feel free to examine them when you visit the Horticultural Research Center. For additional information on disease resistant apple trees, contact Dr. William J. Manning in the Department of Plant Pathology. This activity is supported by the Massachusetts Cooperative Extension Service. Table 1. Performance of young disease resistant apple trees in Massachusetts in 1982. % foliar disease No. No. (100 leaves evaluated/ tree) trees Cultivars Scab Rust Frog-eye fruit % Scab 2 Macfree ■ 0 18.5 22.5 35 0 4 Nova Easy-gro 0 0.5 15.5 16 0 4 NY 61345-2 0 0.5 23.3 16 0 2 Priscilla 0 4.0 15.0 3 0 2 Sir Prize 0 32.0 75.5 0 0 3 Liberty 0 1.3 11.3 35 0 2 Imp. Mcintosh 48.5 44.0 20.0 19 26.3 -10- DISEASE MANAGE^fENT FOR APPLES IN MASSACHUSETTS: 1982 RESULTS AND SUMMARY OF THE FIVE-YEAR PROGRAM Christopher M. Becker,^ Ted R. Bardinelli,2 Daniel R. Cooley,^ Kristin G. Pategas,^and William J. Manning^ Department of Plant Pathology University of Massachusetts, Amherst The five-year pilot program to develop and evaluate new and innovative apple disease management practices in Massachusetts terminated in 1982. Our results for 1982 and a summary of the entire program are presented here. 1982 Results In 1982, 13 commercial apple orchards were involved in the program. Four followed traditional disease management practices and served as controls for comparisons. The other 9 were visited by scouts on a regular basis and ap- plied fungicides to manage apple scab (and other diseases) on a "post-infection" basis only. Hygro thermographs were used to determine when infection periods had occurred and when fungicides should be applied. A more complete descrip- tion of the disease management program can be found in Fruit Notes 46(1) pp. 3-4. Like many growing seasons in Massachusetts, 1982 was unusual. New green apple leaves emerged at the same time that mature ascospores of the scab fungus were available. Two extensive Infection periods occurred in late May with heavy inoculum released. Primary scab season ended on 4th June. A complete summary of wetting and infection periods for 1982 is given in Table 1. Fungicide usage and fruit disease incidence for disease management orch- ards are given in Table 2. Results for control orchards are In Table 3. Disease management orchards averaged one less fungicide application. Reduc- tion in dosage equivalents (2.6 fewer than controls), however, resulted in savings of $32 per acre for fungicides. Disease management orchards had a slight increase in per cent diseased fruit at harvest when compared to con- trols. Savings realized with reduced fungicide costs, however, more than offset the slight increase in costs due to a few more diseased fruit at harvest. Paired t-tests were used to compare results from disease management and control orchards (Table 4). No significant differences (P = 0.05) were found between the number of fungicide applications, per cent diseased fruit at har- vest, and dollar losses from disease. There was a significant difference between actual fungicide usage, or dosage equivalents, and fungicide costs per acre. Disease management growers used less fungicide without significant increases in fruit diseases at harvest. Variation in the number of fungicide sprays (8-14) and dosage equivalents (5.67-11.88) in IPM orchards is closely related with both efficiency in timing of scab sprays, and the necessity for fungicide applications for diseases other than apple scab, especially the rusts, and powdery mildew. When post- infec- tion scab sprays were too late to Inhibit apple scab infections, or poor cover- age was achieved by spraying during windy weather, additional fungicide appli- llPM Technician 1981-82 ^IFH Technician 1978-80 3Extension Technician ^IPM Scout ^Professor of Plant Pathology -11- cations at high rates were necessary to "burn-out" or eradicate scab lesions. Where rust control was essential, protective sprays were necessary before all wetting periods (over 4 hours in length) as post-infection applications of fungicides are not possible for rust management. Five- Year Summary A cost/benefit analysis for the five-year program is presented in Table A. In each year of the program, disease management growers made fewer fungi- cide applications, with fewer dosage equivalents, and reduced fungicide costs, compared to control growers. Per cent diseased fruit at harvest in disease management orchards was either comparable to or only slightly higher than in control orchards. Disease management benefits per acre were variable, but always positive for cooperating growers. When we examined the results for a five-year period, three trends became evident to us. The first was that disease management benefits are most likely to occur at a higher dollar level in dry spring seasons, as in 1980, rather than in wet ones, as in 1982. With fewer wetting periods, greater efficiency can be achieved in timing post-infection sprays. The second trend is that continued benefits from disease management de- crease in magnitude with time. Fungicide sprays and dosage equivalents can- not be further reduced in number every year. Many control growers have also begun to adopt disease management practices, obtained from the numerous Ex- tension education programs we have been involved in over the past five years. It is becoming increasingly difficult to find control orchards where only traditional methods are used. Per cent disease incidence for the five-year period is summarized in Table 5. Apple scab incidence has been reduced. The trend for calyx end rots, however, is increasing slightly. Timing sprays only for scab manage- ment may have increased infection possibilities for end rot fungi before or after bloom. Using fungicides that are good for scab management may also mean that they are not as good for end rot management. Anytime a practice is changed, we can expect that new problems may develop. The use of one or more sprays of a protective fungicide, rather than a "post-infection" or "kick-back" material, from tight cluster to petal fall, should eliminate calyx end rot problems, especially during wet growing seasons. Acknowledgements : We have been able to obtain considerable information about apple disease management during the last five years. We could not have done this without the enthusiastic and generous support and cooperation of the participating Massachusetts fruit growers. This program was supported by special funds from the USDA, by the Massa- chusetts Cooperative Extension Service, and the Massachusetts Fruit Growers Association. 12- Table 1. Wetting and infection periods for the apple scab fungus at the Horticultural Research Center in Belchertown, MA in 1982 Apple growth Wetting Periods Rain % Mature apple scab Potential Hour Duration Mean Temp. primary- Date stage began (hrs . ) CF) (mm) ascospores scab infec- tion severity A/17/82 Green tip 20 8 50 17.2 5 None 4/21/82 Green tip 8 5 48 4.5 10 None 4/24/82 1" green 22 8 52 0.01 23 None 4/26/82 1" green 13 24 52 23.5 25 Heavy 4/27/82 Tight cluster 23 12 40 4.6 25 None 5/8/82 Early bloom 24 9 51 0.7 55 None 5/19/82 Petal fall 23 4 67 7.8 55 None 5/22/82 Petal fall 22 58 44 16.1 53 Heavy 5/29/82 Late petal fall 1 34 56 70.8 50 Heavy 5/30/82 1/4" fruit 24 14 58 0.5 30 Moderate 6/1/82 1/4" fruit 21 15 60 24.5 5 Moderate *6/4/82 1/4" fruit 17 91 52 93.2 3 Heavy *End of primary scab season. 13 Table 2. Cost/benefit analysis of fungicide usage and fruit quality in disease management orchards in 1982 Orchard % Diseased fruits at harvest $ Loss to disease per acre Number of fungicide sprays Dosage equivalents Fungicide cost per acre 1 0,1 scab 0.1 end rot 7.70 11 8.26 $ 81.75 2 0.1 scab 0.1 black rot 1.1 end rot 1.1 quince rust 92.40 11 11.76 $122.72 3 0.1 scab 0.2 quince rust 1.8 end rot 80.85 11 10.2 $100.40 4 0.3 scab 0.1 quince rust 2.3 end rot 0.1 black rot 107.80 14 11.88 $113.46 5 0.2 scab 7.70 14 10.32 $121.28 6 0.1 scab 0.1 quince rust 0.1 bitter rot 2.8 end rot 119.35 10 8.80 $ 95.01 7 0.1 scab 19.25 11 8.48 $ 97.14 8 0.4 end rot 15.40 11 9.44 $122.31 9 0.1 end rot 3.85 8 5.67 $ 66.18 Avg. 0.11 scab 1.00 end rot 0.16 quince rust 0.04 other 1.31 TOTAL 50.48 11.20 9.42 $102.25 14 Table 3. 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C re >, o • -H C£i M) » O • "in ^— s 4^ o ^ (/I .— -3 — o ^ ^^ — -^ = u i~ O U o o o j; c u- > w ^- ^^ . re c ^ Ln >^ >-< ^ aj ~ •(-> •J -»^ 4-» S • O c 3 o c- o o re ^ •• 4-1 — -v> VI u. O c Ui ~ - CO Ln ra c s lU oo = Ln u .-. o u < 4-' ■3 >- u (U .. Um ^ 1 a ^— ' C: O • O -u ro 00 U in o u V) ^ U !- ^ -H • -3 ••- re •— o ^ D. 4^ l:_ re O O 3 >. >v > CO ■ ^ O ^-^ r^ re o >, U O u cr i« V) ■M -O c 5 o o c •A (- OO L- ^ ra tr. > O c O •^ re re = s- w c 4-> O re re VI -3 VI U 0) VI dj C o >- V 4-> 3 re u -O ' 4-' c t— ( J2 re o •r^ « "*v^ 3 o — s £ o -^ V. > MO U •M o Ln • c ^ T>H a. ra rsj • r« « c ^^■ ^ c VI c 4-1 U f^ o o o s; o O -H •3 3 r-^ •3 3 "3 *- ^ = O *— O — V. 5 w •J VI 3 H> Ln ^ re Z re « o 33 Table 6. Cost/benefit analysis of arthropod pest control practices in IPM vs Check blocks, 1978-1982. Difference IPM vs Check 1978 1979 1980^ 1981^ 1982^ Cost of materials Oil Insecticide Miticide Aphicide - $5.81 -$12.51 -$15.83 0.0 +$ 0.23 -$51.64 -$14.59 -$ 0.11 -$ 2.84 -$42.50 -$19.49 -$ 4.30 -$ 2.62 -$37.01 -$16.85 0.0 +$ 1.30 -$51.92 +$ 6.37 +$ 3.33 Cost of pesticide application -$ 9.64 -$16,05 -$ 7. 32 -$ 8.96 -$12.18 Value of fruit lost due to insect injury -$53.37 -$40.46 -$16.42 +$25.26 -$ 3.85 Avg. net benefit from IPM +$97.16 +$122.83 +$93.37 +40.18 +$56.95 Five year average net benefit from IPM +82.10 '1980 data = Complete cooperator blocks. 1981 data = Previous- Year IPM blocks. 1982 data = Complete cooperator IPM blocks OD 9 C CI 8 > 7 6 u u S Clt ID CD 4 O Q J Figure 1. Trends in Pesticide Usage and Insect Injury to Fruit, 1977-1982. 34 Insecticide Usage IPM»— — • X - 6.3 CHECKO O X • 8.5 b. Hiticide Usage CHECKO O ^ ~ ^-^ (8) (9) (7) -N. V- ■^-^ (8) (16)^ '''(19)-""^ (36) 1 1 (18) 1 —i 1 on o a •77 '78 '79 '80 '81 '82 -8- apples were resistant to breakdown regardless of the concentrations of other elements. 100 o o < UJ q: < z UJ 80 UJ O tr. UJ Q. r • -.401 • • • » staff i\*»|^.»«* • • ^ 100 130 160 190 " 250 ppm CALCIUM, OUTER CORTEX TISSUE Figure 1. Scattergram showing percent breakdown after air storage in relation to the Ca concentration in fruit at harvest for each of the 172 commercial samples surveyed, 1979- 1982. Our study reaffirms the importance of establishing adequate Ca concentrations in Mcintosh apples if they are to be stored for long intervals. There are 2 feasible approaches to this: foliar and post- harvest applications of Ca. Application of a total of approximately 75 lbs. of CaCl2 per acre during the growing season can raise fruit Ca concentrations by about 50 ppm, and a postharvest dip in 4% CaCl2 can increase it by about 35 ppm. It is evident that many commercial samples did not contain adequate Ca concentrations and that they would have benefited from the above treatments. The are rest and rot. after st inf luenc ly soft and soft storage harveste temperat exhibit position manageme effe ricte Pro orage ed by fruit ening manag d ove ure o infer s doe nt. cts of m d to the bably th is the variati is unac of the ement . rmature, r at the ior qual s not re ineral nutrition occurrence of d e most significa firmness of the ons of any of th ceptable, whethe fruit is control Regardless of th cooled improper wrong atmospher ity after storag duce the need fo on apple quality recorded here isorders (breakdown and scald) nt attribute of Mcintosh quality fruit, and fruit firmness was not e minerals surveyed. An excessive r or not it develops disorders, led primarily by harvest and eir mineral concentrations, apples ly, or stored at too high a ic composition are likely to e. The best of mineral com- r careful harvest and storage THE APPLE MARKETS FROM 1967 THROUGH 1982, LOCALLY AND NATIONALLY William J. Lord Department of Plant and Soil Sciences We have summarized yearly since 1967 the apple production in the United States and in Massachusetts, and the F.O.B. prices at Country Shipping Points in Massachusetts for 120 counts, U.S. Fancy or better Mcintosh apples^. This information, which is pre- sented in Table 1, indicates some of the factors that affect the profitability of a marketing season. Marketing Seasons 1967-68 and 1968-69. Nationally these were "short" crop years and prices for Massachusetts grown apples were good. The fruit were in good condition and the demand for CA Mcintosh was strong. 1969-70. The national crop was the second largest in 30 years'^ This contributed to lower wholesale prices for Massachusetts- grown apples than for the 2 preceding marketing seasons. Apple growers in the western states of the U.S. produced about 17 million more bushels in 1969 than in 1968 but received $41 million less for their crop2. In Massachusetts, "Soft Mcintosh Problem" was encountered after CA storage and wholesale prices remained low for the entire season. 1970-71. The hot summer and fall reduced fruit quality in New England, Appalachia and Hudson Valley and many growers had low pack- outs because of poor fruit color and condition. In Massachusetts the returns for the large sizes of Delicious were better than in 1969-70 and prices for CA Mcintosh finished strong. 1971-72 . The 3rd consecutive national crop greater than 50 million was produced. U.S. growers asked the Secretary of Agri- culture to appoint a team to study the marketing problems of the apple industry because of low net returns during these years. (A report of the team's findings with their recommendations as to needed action was published in 1972. The team did an excellent job of identifying the marketing problems of the apple industry, most of which still persist.) Slow color development in Massachusetts delayed the harvest and marketing season and resulted in the harvest of too many large, soft, poorly colored apples. Massachusetts growers harvested 1 Taken from the Special Apple Market Report published by the Division of Markets, 100 Cambridge St., Boston, MA. 2 The Good Fruit Grower, Sept. 15, 1970. 10- through the entire month o£ October. Prices for Mcintosh apples from regular storage averaged only slightly higher than in 1970-71 and most growers lost money on bagged apples. During May and June, 1972, some Massachusetts growers again encountered the "soft Mcintosh Problem". Low prices for CA-Mclntosh through the remainder of the marketing season reflected the market concern about fruit softness , 1972- 75 . A small crop was harvested in Massachusetts and in the U.S. as a whole. Prices in Massachusetts were $0.75 to $1.00 higher for regular storage Mcintosh than during the previous year. Stored Mcintosh kept exceptionally well, no soft Mcintosh were encountered and prices reflected this quality. 1973- 74 . The U.S. apple production was higher than in 1972 but the New England apple crop was the smallest since 1956 because of frost and poor pollination weather. Massachusetts experienced extremely hot weather from August 27 through September 4, 1973 and fruit probably softened rapidly. After September 4, the weather became favorable for color development. Due to a short Mcintosh crop, a light crop in eastern U.S., and an increasing demand for juice and sauce, prices were very favorable for apples from regular storage. Most growers made money on their bagged apples, which is not a common occurrence. In early March of 1974, some storage operators again encoun- tered soft Mcintosh, especially with larger sizes. Although the problem was not as serious as other years the market reflected its concern. 1974-75. The national crop again exceeded 150 million bushels and in New England it was 30% larger than in 1973. Mcintosh apples in Massachusetts were smaller than usual, but the harvest season was favorable for good color development. Prices for regular storage Mcintosh were only slightly higher than during the previous season. The prices for bagged and juice apples were lower than in 1973, and those for CA Mcintosh reflected the sof t-McIntosh problem encountered the previous year. Mean- while, production and marketing costs increased drastically because of the energy crisis. 1975-76. The national crop was a record 178 million bushels with 52 million from Washington alone. The early crop forecast for New England was a 15% increase from 1974. However, rains delayed harvest and drop was excessive in some orchards. Consequently, storage holdings in Massachusetts were less than the previous season. Prices for 120 counts were $0.75 to $1.00 less than during the previous season for regular storage Mcintosh and somewhat less for 11- those from CA storage. Consequently, growers who sold mainly wholesale lost money. New York and Washington growers also had no profit from the record apple crop of 1975. New York had its largest apple crop in 50 years, but apples were left unpicked because of heavy carry- over of processed apples, the bumper crop, and financial problems of processing plants. 1976-77 . The national crop decreased to 154 million bushels, but in Massachusetts it was somewhat larger than during the previous year. Prices for both regular and CA storage Mcintosh in Massa- chusetts were very favorable throughout the 1976-77 marketing sea- son. No soft Mcintosh were encountered and prices of those from CA reached $11.00 in May and June. 1977-78 . A national crop in excess of 160 million bushels was harvested. The New England crop was up 101 over 1976. In Massachusetts frost reduced the Delicious crop. Wholesale prices in Massachusetts were about the same as in 1976 for regular storage Mcintosh but a strong demand for CA apples pushed prices higher later in the season. The 1977-78 marketing season was the 2nd consecutive profitable year for most Massachusetts growers. The market for apples con- tinued to improve during the late 1970 's because of increased demand for fresh fruit and a growing demand for apple juice and cider . 1978-79. The national crop was about 101 higher than in 1978 with the increase being greater in the eastern and central states than in the western states. Harvest in Massachusetts was 10-14 days later than in 1977. However, weather during harvest was ideal with warm days and cool nights and no rain. Marketing started about 10 days later than usual in Massachusetts, but movement was good and the prices received were higher than dur- ing the previous marketing season. 1979-80. Massachusetts crop was down about 101, whereas the national crop was larger. Some drop of Mcintosh was experienced in late-August but weather became cooler and drop was not troublesome thereafter. Many growers had an "umbrella" crop of Mcintosh, thus they harvested many less fruits than originally anticipated. Apple prices remained at the same level as in 1978-79. How- ever, no soft Mcintosh were encountered from CA storage and the price for these apples in April and May finished strong. Nationally, this was the 4th consecutive large national crop marketed without encountering the burden of over supply. One 12- reason these large crops were manageable was the strengthening of the export market. Market opportunities developed in the Middle East, Latin America, and the Far East. In 1979-80, U.S. apple exports reached 12.4 million bushels. In the 1960's the U.S. was exporting only about 2 million bushels, with Canada taking close to half of those. 1 980-81 . The U.S. apple industry encountered an oversupply due to a national crop in excess of 210 million bushels. However, the crop size in Massachusetts was similar to that of the previous year. The harvested fruit was small in some Massachusetts orchards due to dry weather. The season was 10-14 days late but rain did not interfere with harvest. Apple prices were quite favorable for 120 count Mcintosh in September (approximately $11.00) but they declined to about $9.00 by early December. Basically, the poor movement and decline in prices was caused by the supply pressure from Michigan and Washing- ton. The prices for 120 counts increased $0.50 with the opening of CA storages but remained at this level for the remainder of the marketing season. 1981-82 . It was estimated that the New England apple crop would be 201 less than in 1980. Massachusetts experienced a freeze on April 22 and most orchards had poor pollinating weather at bloom. Thus, few orchardists had a large crop. New York state apple crop decreased from 26 million in 1980 to about 19 million in 1981. Production also decreased in Mich- igan, Ohio, and Pennsylvania. Prices for U.S. Extra Fancy Mcintosh 120 count started at $11.00 in September, increased to $12.25 in October and $13.25 in December. Mcintosh were scarce in April and CA Mcintosh fin- ished in middle May at $14.75 for 120 counts. The large Washington state crop and small fruit size hurt the New England's bagged Delicious market. The Washington crop suppressed sales in the 1982 crop of Paulared. 1982-85. Less apples were harvested than anticipated because of the presence of small, seedless fruits on trees in many Massa- chusetts orchards. Fruit color developed rapidly in late August and Friday prior to Labor Day (Sept. 3) some growers picked Mcin- tosh apples for CA storage. Unfortunately, color developed slowly thereafter. The early market in September was "soft" in Massa- chusetts because of carry-over of the 1981 Washington crop. The carry-over hurt the sales of Paulared and September sales of Mcintosh. This and other factors including a large national crop of apples and oranges, poor fruit color, and storage disorders were -13- largely responsible for the unfavorable prices during the 1982-83 marketing season (Table 1). In October, 1981 prices quoted for Mcintosh Extra Fancy 120 counts in the Special Apple Market Report averaged $11.00 and by December had risen to #13.25. In contrast, apples started at $8.75 in October, 1982 and prices were virtually unchanged fro the remainder of the 1982-83 marketing season. Summary For the 5-year period from 1964-68 the national crop averaged about 132 million bushels. From 1973-77 it averaged 158 million, a 19% increase. The average production for the 5-year period 1976-80 increased to 178 million, 12% over that of 1973-77. The production nationally fluctuated from a low of 128 million bushels in 1967 to a high of 210 million bushels in 1980. To the contrary, apple production of Massachusetts remained quite stable from 1967 through 1982. Over supply occurred during the 1969-70, 1970-71, 1975-76, 1980-81 and 1982-83 marketing seasons. Due to heavy plantings, especially in Washington, it is possible that we may again have devastating surpluses which will depress prices, increase wastage, reduce interest in new plantings and cause orchard abandonment. During the period from 1967 through 1982 many factors affect- ing the profitability of a marketing season were evident. These include the size of the national crop, the regional distribution of the crop, weather prior to and during harvest, the keepability of stored apples, the demand for processing apples, the export market and the earliness or lateness of the marketing season. Table 1. Apple production in the United States and for Massachusetts and F.O.B. prices at country shipping points in Massachusetts, 1967 through 1982. Year Crop size U.S. (million bu.) Mass. Avg price for . Storage season ($) CA CAj )rice Start End of of season season 1967 128 2.5 4.58 5.83 5.00 6.75 1968 129 2.1 5.00 6.28 5.75 7.00 1969 159 2.4 4.17 4.46 4.60 4.50 1970 151 2.6 3.75 5.10 4.75 6.00 1971 152 2.7 3.59 3.19 5.10 5.25 1972 139 2.2 5.18 6.31 5.60 7.50 1973 147 1.8 7.23 7.85 7.75 8.15 1974 154 2.2 7.64 8.02 8.00 8.40 1975 179 2.0 6.72 7.70 7.35 8.00 1976 152 2.2 7.89 7.70 8.65 11.00 1977 164 2.1 8.16 9.59 8.75 13.00 1978 182 2.4 9.24 9.98 10.25 11.25 1979 193 2.3 9.28 7.81 9.75 13.40 1980 210 2.3 9.52 9.50 9.50 9.50 1981 182 2.0 12.27 14.41 13.75 14.75 1982 195 2.4 8.78 8.73 8.25 9.75 -14- CIDER NOTES Kirby M. Hayes Department of Food Science and Nutrition A question that often arises is how to make good cider. Although there is no easy answer, or hard and fast rules, two of the most important factors to consider are maturity and variety. Maturity Firm, ripe apples- - those that are ripe enough to eat out of hand- -make the best cider and give the highest yield. Immature or overripe apples lower the quality. Early-maturing varieties should be allowed to ripen sufficiently to yield a high-quality juice . Variety The best cider is usually made from a blend of different var- ieties of apples. A blend provides an appealing balance of sweet- ness, tartness, and tang, as well as aromatic overtones. A single variety of apple seldom makes a satisfactory cider. However, "Mcintosh" has been used alone successfully, but only at the peak of its maturity. Sometimes the desired fullness and balance can be obtained from two varieties. A blend of three or more varieties is better. Using several varieties, permits greater latitude in varying the proportions to obtain the desired blend, and also allows practical management of the available supply. Many commercially important varieties may be separated into four groups according to their suitability as cider material: Sweet subacid, mildly acid to slightly tart, aromatic and stringent, A strict classification is not possible because many varieties have a number of different flavor characteristics. For example, "Deli- cious" may be listed in both the sweet subacid and aromatic groups. Moreover, varieties differ in their characteristics from one area to another. Varieties in the sweet subacid group are grown primarily for eating raw; they usually furnish the highest percentage of the total stock used for cider. Varieties in the aromatic group have outstanding fragrance, aroma and flavor that are carried over into the cider. -15 Crabapples, in the astringent group, provide tannin - a constituent difficult to obtain in making a high-grade cider. The juices of this astringent group also are highly acidic. Only a small quantity of these apples should be used in the blend. Use of the following list as a guide in selecting the right blend of varieties. Sweet subacid group: Baldwin, Delicious, Cortland, Spartan, Empire, Macoun. Mildly acid to slightly tart group: Winesap, Jonathan, Northern Spy, R.I. Greening, Roxbury Ru s s e t . Aromatic group: Delicious, Golden Delicious, Mcintosh, Empire. By fitting the above suggestions to your operation, using sound clean apples, pressing in a clean mill, and storing and displaying the finished product under refrigeration, you can keep your customers coming back for more. POMOLOGICAL PARAGRAPH What are genetic dwarfs? This question is common now that genetic dwarf varieties of peach, apricot, nectarine and apple are avail- able to commercial orchardists. Genetic dwarfs are selections of natural mutants or mutants induced by radiation that produce trees smaller than typical. Thus, the dwarfing is induced by the scion variety rather than the rootstock. Trees of Starkspur Compact Mac and peach and nectarine varieties are very small and could be grown in a tub on a patio. The internodes on these trees are so short that the wood is flat and thickened. In contrast, trees of the genetic dwarf Compact Red Delicious (Cascade strain) has "normal" appearing wood because of greater internodal spacing and may be 10-12 feet in height when on a seedling rootstock. We are currently testing the Compact Red Delicious , Starkspur Compact Mac and some dwarf nectarine varieties at our Horticultural Research Center in Belchertown. 16- THE STARCH TEST GUIDE FOR APPLE MATURITY William J. Bramlage Department of Plant and Soil Sciences Once apples begin to ripen, a large portion of the potential benefit from CA storage is lost, since CA has the capability of suppressing the beginning of ripening. It is therefore very help- ful in harvest management to know which apples are and which are not yet ripening. The most precise measure of the onset of ripen- ing is through ethylene analyses since ripening is accompanied by a huge burst of ethylene production. Unfortunately, methods for measuring ethylene production during commercial harvesting have been hampered by many technical difficulties and few observers feel that ethylene measurements are commercially feasible today. It has long been known that as apples ripen, their starch is rapidly converted to sugar. Starch concentrations, starch pat- terns, and starch conversion rates vary among varieties and are influenced by environmental conditions, yet for some varieties the changes can be very clear and dramatic. Mcintosh is such a variety. At the University of Guelph, in Ontario, extensive stu- dies led to the development of a very simple procedure for measuring the progress of ripening in Mcintosh by following the loss of starch from the fruit. The test is based on the fact that starch, but not sugar, will react with iodine to form a blue-black color. To perform the test, a random sample of 10 to 20 fruit are cut open and half of each apple is immersed briefly in a shallow dish containing an iodine solution. The apples are allowed to sit a minute or 2 to allow the color to develop, and the color is then matched to a chart which tells whether the apples were "immature," "mature," or "overmature." For "finer tuning," each of these classes is subdivided into 3 numerical classes. This very simple, rapid test allows growers to see for them- selves the stage of development of their fruit. Periodic sampling of fruit from different blocks can give them an ongoing view of where ripening is occurring fastest, and help in determining when and where to pick. The test also can be a very important guide in deciding which fruit should be directed into Ck storage. Cer- tainly, batches of fruit in which a large percentage of the apples are scoring as "overmature" should not be placed in CA, as they are too ripe to hold up during and following storage. 17- All that is needed to perforin the starch tests are (1) a chart with instructions; (2) some iodine and potassium iodide crystals; (3) a shallow dish; and (4) a pocketknife. A chart is available, entitled "Evaluating apple maturity. Using the starch-iodine test." It can be obtained free from Dr. E.G. Lougheed, Horticultural Science Department, University of Guelph, Guelph, Ontario, Canada NIG 2W1. The chart also contains instructions for testing apples. The chemicals can be obtained from a pharmacist, who may have to order them for you. Although they are expensive, small quantities go a long way. The chart described above includes a recipe for making up the chemicals, but a simpler recipe has been suggested by Dr. M.E. Saltveit, Jr., formerly at North Carolina State University. It is as follows: "First dissolve 1 level teaspoon of potassium iodide crystals in approximately 1/8 cup clean water in a 1-quart container. Gently swirl the container until the crystals dissolve. Next, add 1/4 teaspoon of iodine and swirl the container until the iodine dissolves. Finally, di- lute this solution with clean water to make one quart. This solution is sensitive to light and should be kept in a dark container, such as a glass jar wrapped in aluminum foil. Fresh solution should be made every season." The above chart is designed for use on Mcintosh, and the brochure contains an accompanying chart for use with Delicious. North Carolina also has a brochure available with charts for De- licious, Golden Delicious, and Law Rome. ("Determining the matu- rity of North Carolina apples. The starch- iodine staining technique." Publication AG-282). It ws prepared by M.E. Salt- veit, Jr. and Susan A. Hale, Dept. of Horticultural Science, North Carolina State University, Raleigh, NC 27650. We strongly urge growers to try the starch- iodine test for apple maturity, and to see for themselves the clear changes that are portrayed by the tests. We believe that the tests will pro- vide information that will make it easier for growers to make wise decisions during a very stressful period. POMO LOGICAL PARAGRAPH Storage temperature for Mcintosh in CA. The correct temperature for holding Mcintosh in CA is 36-38-F. Growers operating their rooms at less than 36 -F are increasing the risk of low temperature injury, as occurred during the 1982-1983 storage season. Symp- toms of low temperature injury this past storage season were a brownish-gray discoloration around the stem-end of the apple and/or internal browning of the flesh near the core of the apple. -18- POSTHARVEST CALCIUM CHLORIDE TREATMENT William J. Bramlage Department of Plant and Soil Sciences Our orchard surveys have shown that approximately one-third of the commercial samples of Mcintosh apples in Massachusetts are at such low calcium (Ca) concentrations that they possess a high risk of developing breakdown after storage. Most other samples contain Ca concentrations that carry a lower risk of breakdown, but they could still benefit from some additional Ca. There are 2 feasible ways of successfully applying Ca to apples: tree sprays and postharvest drenches. Even when a con- scientious tree-spray program has been followed, apples can usually still benefit from postharvest treatment. Thus, posthar- vest Ca treatments have potentially wide benefit for the fruit industry. A postharvest Ca application is viewed as a food-additive process by the Food and Drug Administration. That agency has stipulated that "Brining Grade" calcium chloride, containing 94% ^^^^2, is acceptable for postharvest use. The technical flake CaCl? commonly used for tree sprays is still acceptable for tree sprays, but it may not be used for postharvest treatments. There for e~| anyone wishing to use postharvest CaCl2 treatments must obtain the Briner's Grade material, which is now readily available from suppliers. CaCl2 may be combined with scald inhibitors and fungicides in the postharvest treatment solution. Cornell University has recommended the following mixture for postharvest treatment of Mcintosh: 21 lbs of CaCl2 per 100 gal of water h lb of Benlate* or 16 fluid ounces of Mertect* 1 lb of Captan 1000-2000 ppm DPA We suggest that h quart of vinegar also be addded to this mixture in 100 gallons of water. The vinegar neutralizes the CaCl2, which otherwise makes the solution alkaline. There is evidence that the alkaline solution may cause the fungicides to break down rapidly in solution, and the addition of vinegar can protect against their alkaline degradation. Trade names -19- In use of postharvest CaCl2 drenches, it is important to understand that little or no Ca enters the fruit during the drenching process. The purpose of the drench is to leave a resi- due of CaCl2 on the fruit. Ca is slowly absorbed by the apple from the residue during storage. Therefore, the drench is never followed by a rinse, which would remove the residue. Further- more, for Ca to be absorbed from the residue, the residue must not dry out. The apples should not be allowed to air-dry before storage. If the storage is operating at the desired relative humidity (90-95%), the residue should not dry out. However, if the storage is operated at less than 90% relative humidity the residue may dry out and no Ca uptake will occur as a result of the drench treatment. We have encountered no difficulty from this residue when apples are removed from storage. It will be removed if apples are water-dumped, but even with hand-packed fruit no difficulty has been reported. CaCl2 drenches can cause fruit injury, which occurs as tiny black spots on the surface of the fruit. Generally, these spots are concentrated in the calyx cup of the apple and are not objec- tionable, although under some circumstances they may coalesce into more unsightly blotches or may occur at the lenticels on the cheeks. Do not exceed the recommended CaCl2 concentration, as risk of this injury escalates rapidly at higher concentrations. CaCl2 is also corrosive, so equipment should be thoroughly cleaned at completion of treatment. However, with appropriate rinsing corrosion should not be a concern. The purpose of the postharvest application of CaCl2 is to reduce the risk of breakdown, rot, and scald during but especial- ly after storage. The recommended treatment will not make fruit firmer, but will improve their ability to hold up during market- ing. Treatments will be of greatest benefit to mature fruit des- tined for long-term storage. Overripe fruit cannot be expected to benefit significantly from a CaCl2 treatment. -20- ACID RAIN AFFECTS APPLE MAGGOT FLY EGGLAYING Averill and Ronald J. I Department of Entomology 1 2 Anne L, Averill and Ronald J. Prokopy Acid rain occurs when airborne sulfur and nitrogen oxides originating from combustion of fossil fuels are washed to the earth during rainfall as sulfuric and nitric acids. In addition to being a popular topic in magazines and newspapers, this phen- omenon is a complex political issue: although Massachusetts has the most acidic precipitation in the country, many scientists be- lieve that the bulk of our rain's contamination emanates from Midwestern smoke stacks. Residents of the Northeast have become progressively concerned and bitter as an increasing number of scientific studies demonstrate detrimental effects of acid rain, especially on aquatic ecosystems, soils, and crop and forest vegetation. In the course of studies of apple maggot fly egglaying be- havior, we noted a particularly intriguing effect of acid rain. Our observations suggested that a host fruit exposed to acid rain was less acceptable to the flies for egglaying than was an unexposed fruit. To test this possibility more thoroughly, we are hanging clean fruits in trees during each of this summer's rains, with some fruits protected from rainfall by plastic hoods. These fruits are brought to the lab, and by observing the number of flies which attempt egglaying, we can evaluate the influence of rain exposure on fruit acceptibility . Acidity (pH analysis) of each rain event is determined by Dr. O.T. Zajicek of the Depart- ment of Chemistry at UMASS. Thus far, most rains have fallen into 1 of 2 categories: those with pH values well below 4 (3.6-3.8) and those with pH values above 4. These categories largely reflect the dominant weather pattern at the time of the storm. Usually, the more acidic contaminated storms (pH 3.6-3.8) move into our region from the Midwest and the less contaminated storms move in from elsewhere. The data available to date (Table 1) show that apple maggot egglaying was not influenced when fruits were washed by rains with a pH above 4, whereas egglaying was significantly decreased when fruits were washed by rains of pH 3.6-3.8. This phenomenon may be explained by the fact that apple mag- got flies have contact chemical receptors (hairs) which are loca- ted on the bottom of their feet. Via these receptors, a fly may receive cues emanating from the fruit to control steps in fruit acceptance and egglaying. The presence of acids on the fruit surface may interfere with perception of these cues, or may ac- tually damage or destroy the chemical receptors. Whatever the explanation for our observations, it is possibly to our advantage, and to the disadvantage of the apple maggot fly, that acid precipitation is most severe in the summer months during peak fly activity. 2Graduate Student Extension Entomologist -21 Table 1. Percent arriving apple maggot flies attempting egglay- ing into fruits exposed to summer rain storms. Non rain-exposed fruits were protected from rain under plastic hoods. -a ^ Rain with Attempted Rain with Attempted, pH 4.0-4.2 egglaying^ pH 3.6-3.8 egglaying Non rain-exposed Non rain-exposed fruits 50 fruits 65 Rain-exposed Rain-exposed fruits 55 fruits 46* , Average of 6 storms Average of 3 storms *Signif icantly less than egglaying into non rain-exposed fruits NEW PUBLICATIONS AVAILABLE Two new publications are available to the public. One, entitled "Postharvest disorders of apples and pears," was prepared by S.W. Porritt and M. Meheriuk of the Agriculture Canada Research Station, Summerland, British Columbia, and by P.D. Lidster of the Agriculture Canada Research Station, Kent- ville. Nova Scotia. It contains excellent color prints of various disorders along with very useful information about the disorders. It is available free, as Publication 1737, from the Communications Branch, Agriculture Canada, Ottawa, Ontario K1A0C7. The second publication was prepared by CD. Blanpied and R.M. Smock of Cornell University and is entitled, "Storage of fresh market apples." It contains a great deal of information on current thinking about apple storage management, and is available as Information Bulletin 191 for a fee from Distribution Center C, 7 Research Park, Cornell University, Ithaca, New York 14850. The fee is $4.50 per copy. Send a check or money order payable to Cornell University. Be sure to print your name, complete address, and ZIP code clearly on your request for the publication. ■22- FRUIT NOTES INDEX FOR 1983 (This index of major articles has been prepared for those who keep a file of FRUIT NOTES. The number in parenthesis indicates the pages on which the item appears.) WINTER ISSUE - Vol. 48, No. 1 Varieties of Grapes for Massachusetts (2-3) Varieties of Peaches for Massachusetts (4-5) Performance of Disease Resistant Apples in Massachusetts (6-9) Disease Management for Apples in Massachusetts: 1982 Results and Summary of the Five-Year Program (10-16) Factors Affecting Nutrient Content of the Foliage and Fruits of Apple Trees (17-23) Integrated Management of Apple Pests in Massachusetts, 1982 Results: Insects (24-34) SPRING ISSUE - Vol. 48, No. 2 Nutritional Problems in 1982 and Suggestions for Fertilization of Apple Trees in 1983 (1-4) Effects of Type of Nitrogenous Fertilizer Applied Under Sturdeespur Delicious Trees on Exchangeable Elements in the Soil (4-5) Preliminary Findings from the Multi-State Cooperative Apple Interstem Planting (5-6) Future of Tree Fruit IPM in Massachusetts (7-8) Sampling Soil for Nematodes (9) Pruning Plum Trees (9-11) A Visual Monitoring Trap for the Apple Blotch Leafminer (11-14) Are High Density Strawberries on Ridges for You? (15) Suggestions for Use of Calcium Sprays in 1983 (16-17) An Up-date on Calyx-end Rot, and Report of an Apple Leaf Spot Caused by the Fungus Sclerotinia sclerotior ium (17-19) Use of Promalin to Increase Branching of Young Trees (20-22) SUMMER ISSUE - Vol. 48, No. 3 Leaf Analysis Service and Standards for Nutrient Levels (1-4) Gypsy Moth as a Pest of Highbush Blueberry in Massachusetts (5-8) Marketing Your Fresh Fruits and Vegetables (8-13) Spur Blight of Raspberries (14-17) NRAES-16 Planning Farm Shops (18-19) Why, When and How to Summer Prune and Results to Expect (20-23) Extent of Damage by Major Apple Fruit Injuring Insects in Massachusetts (23-25) 23- FALL ISSUE - Vol. 48, No. 4 Cycling Fans in Apple Cold Storage Rooms Can Be a Good Way to Conserve Energy (1-3) Effects of Mineral Nutrition on Keeping Quality of Massachu setts Mcintosh: Results of a Four-Year Study (4-8) The Apple Markets from 1967 through 1982, Locally and Nationally (9-13) Cider Notes (14-15) The Starch Test Guide for Apple Maturity (16-17) Postharvest Calcium Chloride Treatment (18-19) Acid Rain Affects Apple Maggot Fly Egglaying (20-21) Department of Plant and Soil Sciences French Hall University of Massachusetts Amherst, MA 01003 3-20028 Non-Prof it Org. U.S. POSTAGE PAID Permit No. 2 Amherst, MA 01002 FRUIT NOTES PREPARED BY DEPARTMENT OF PLANT AND SOIL SCIENCES COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF MASSACHUSETTS, UNITED STATES DEPARTMENT OF AGRICULTURE AND COUNTY EXTENSION SERVICES COOPERATING. EDITORS W. J. LORD AND W. J. BRAMLAGE Vol.49: 1 WINTER ISSUE, 1984 Table of Contents: Subscription to FRUIT NOTES A Report on the 1983 Apple IPM Program Variations in Tree Form in an Eight-Year-Oid Spur-Type Mcintosh Planting Height Containment on Spartan and Idared Trees Pomological Paragraph - Increased Interest in Cherry Growing Response of Interstem Trees to Planting Depth Using W Clips to Train Fruit Trees Effect of Mineral Nutrition on Keeping Quality of CA Mcintosh in Massachusetts Pomological Paragraph - Differences between M7 and M7a Issued by the Cooperative Extension Service in furtherance 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 subscribers, please send a U.S. postal money order). William J. Lord William J. Bramlage Editors Name Mailing Address Town, State Country _zip Make check payable to: FRUIT NOTES ACTIVITY ACCOUNT Send subscription form and check to: William J. Lord Department of Plant and Soil Science: French Hall University of Massachusetts Amherst, MA 01002 1984 -1- A Report on the 1983 Apple IPM Program W.M. Coli-^, R.J. Prokopy-^, and W.J. Manning' 1983 was a year of transition for Apple IPM in Massachusetts, during which program emphasis shifted from providing scouting and pest management advisory services for a limited number of growers toward a stronger educational and information transfer effort for all the state's growers as well as support of private sector IPM implementation. Grower interest in and support of IPM continued to be excellent, with informal surveys indicating that over 2/3 of the state's total apple acreage is presently under some form of integrated management (e.g. private sector scout/consultants, grower scouting, careful attention to proper timing of pesticide application, or selection and use of IPM-compatible pesticides). In FY 1983, growers contributed $3200 toward the continuation of the program and apple IPM specialist position — a substantial committment when one considers that many of these same growers also paid @$20/acre for private scout/consultant services. Further, a mechanism was established to lease to private parties 9 hygrothermograph units. Extension faculty and professional staff conducted or participated in 12 IPM training sessions (usable for pesticide certification credits) (4 in each of the three major fruit-growing regions of the state.) Entomology Department Plant Pathology Department Acknowledgments: We wish to thank Ms. Kathleen Leahy for scouting and computer-related assistance. Special thanks to Glenn Morin and Roberta Spitko for providing a substantial portion of the harvest injury survey data which is compiled in Table 2. -2- In addition, the Entomology IPM Specialist performed weekly scouting in six commercial, orchards to collect data and samples on insect/mite and disease pest status. With the cooperation of Plant Pathology staff (Mr. Dan Cooley and Dr. W. Manning), Mr. Coli was primarily responsible for maintaining a frequently updated (2 x weekly), computer-based message system accessable by terminals in regional fruit specialist offices. These messages also contained information gathered by other extension staff (Jim Williams, Tom Green and Ron Prokopy), private sector scouts (Glenn Morin, Roberta Spitko, Breck Parker, Wayne Rice and Ed Roberts Jr.) and from weekly access to New York State's excellent computerized information system (SCAMP). Regional specialists sent this information to growers via weekly newsletters and 24 hour code-a-phone devices (over 1370 calls were made to these code-a-phones in 1983, an increase of 20% in utilization over 1982). Numerous favorable grower comments have been received concerning the quality of the 1983 pest messages and their value to growers as management aids. Table 1 is a graph of weekly totals of calls received on Jim Williams' and Karen Hauschild's code-a-phones during the 1983 season (data from Dom. Marini's region are not available since his code-a-phone has no counter.) Total calls received in these regions were 1222. There are several interesting points to note in this graph, including: 1. A six-fold increase in use from week 1 to week 2 as the pest control season began in earnest, particularly with regard to frequent wetting periods and changes in fungal spore maturity. 2. A substantial drop in calls during bloom, followed by a major peak in usage during late May - early June. This peak coincides with the -3- approaching end of primary scab season, as well as the onset of sprays against plum curculio and 1st generation leafminer larvae. 3. Another peak during the week of June 21 when 1st generation San Jose scale (SJS) crawlers first became active. 4. Increased calling from July 12-July 19 following the first reported apple maggot (AMF) capture in an early developing commercial orchard (7/11) . 5. A final period of high usage from July 26 to August 9, a time of decision-making with regard to 2nd generation leafminer (LM) in many areas. 6. It is somewhat surprising to note the relatively low number of calls received thereafter, in spite of the impending activity of 2nd generation San Jose scale crawlers. Other IPM-related information was published in the form of four "Fruit Notes" articles, a paper presented at the annual meeting of the Mass. Fruit Growers Association (co-authored by SJV. Weis, Plant and Soil Science and Dr. J.M. Clark, Entomology) and a symposium talk presented to the Eastern Branch ESA Meetings in Hartford Connecticut (co-authored by F. Drummond, T. Green and R. Prokopy, Entomology Dept). The Entomology Specialist, in collaboration with Dr. Clark, recently applied for and received a $1200 grant from the M.F.GJ^. to perform laboratory work to further investigate effects of spray mix pH on pesticide stability and effectiveness. An additional accomplishment was the receipt of a $6850 grant from USDA to be used to publish a photographic manual of IPM techniques for use on apples in New England. This publication, an expansion of the Apple Insect/Mite Photo manual which many growers have seen at IPM training -4- sessions, will contain over 100 4-color photographs with text on major insect/mite, disease and vertebrate pests of apples as well as a segment on integrated management of orchard cover crops. Insect Pest Injury, 1983 - Direct Pests - Table 2 contains results of on tree harvest injury surveys conducted by extension and private sector IPM personnel. It is interesting to note that tarnished plant bug (TPB) again accounted for the majority of fruit injury observed just prior to harvest. However, with the exception of a few blocks where TPB injury to individual fruit was severe (similar to "cat-facing" injury on peaches), much of this "injury" would pass through a grading line with no effect on fruit grade. While many growers appear to be achieving good San Jose scale (SJS) control, largely due to improved monitoring and better spray coverage, SJS ranked second in importance in monitored blocks (range 0-4.3% injury) in 1983. As was the case last year, SJS crawlers continued activity well into September, when pre-harvest interval considerations made treatment inpossible. European apple saw fly (EAS) injury was about at average levels for the last 5 years (0.40% in IPM blocks, 1978-1982). In 1983, however, much EAS injury consisted of a "dimple" in the fruit calyx, which would likely not affect fruit grade. Green fruitworm (GFW) injury, which will probably result in fruit culling, was up from 5-year averages, largely due to suspected resistance to Guthion and Imidan in several blocks. Growers who experienced substantial injury from GFW in spite of pink and/or petal fall sprays of OP compounds should consider use of other materials (carbamates, for example) in the spray program next year. Most other direct pests were of minor importance in 1983. -5- Indirect Pests - Injury from 2 indirect pests, white apple leafhopper (WAL) , and aphids, was substantial in some blocks. 2nd generation WAL populations reached outbreak levels immediately prior to Mcintosh harvest in at least one monitored orchard (active stages exceeding 10 per leaf). Injury to leaves and excrement on fruit was extensive in this case. A further problem was the annoyance factor of leafhoppers flying into picker's faces during harvest. While aphids were controlled by predators at many sites this year, substantial sooty mold growth on honeydew (as high as 43% of fruit in one case) can probably be explained by lack of significant rain showers in many areas. Pyrethroid insecticides (e.g. Pydrin) provided excellent control of leafminers in almost all cases. Interestingly, growers who used pyrethroids averaged only 1.6 percent TPB injury versus the state average of 2.52%, reinforcing our earlier research plot data which suggested that pyrethroids may be excellent materials for integrating controls of a key direct pest (TPB) and a key indirect pest (ABLM/STLM). Growers who applied carbamate materials against 1st generation miners generally experienced excellent control results. Where 1st and 2nd generation controls were not adequate, 3rd generation moth flight was quite large, as expected. A few growers applied sprays for miners of this generation, even though such sprays may be more harmful then helpful. Spider mites (European red mites, two spotted mites) were a problem at many locations throughout the year, due to hot, dry weather. Frequent reapplication of miticide was needed in some cases to achieve control. Even where controls were applied, some locations experienced late mite outbreaks with renewed hot weather in early September. Levels of our major -6- mite predator Amblyseius fallacis^ were lower than normal this year possibly owing to low overwintering numbers of this beneficial mite or to the effects of pyrethroid or carbamate insecticides directed at other pests. Plans for 1984 - It appears that funding for apple IPM, as well as for IPM programs begun in Mass. in 1983 in other commodities, will continue at present levels in 1984. Based on this premise, we plan to continue with a similar apple IPM effort, focusing particularly on the IPM training sessions and maintenance of an extensive, frequently updated, tree fruit pest message system. We welcome grower suggestions and comments on the pest messages to ensure that grower needs are met. As mentioned above, we expect to publish a field manual of IPM techniques prior to the 1984 growing season. We feel that this publication will provide growers with a comprehensive field reference to identification, life histories, damage, monitoring and control measures for the major New England apple pests. In addition, Massachusetts will be one of a group of states participating in a national study on IPM program impact. This study, under the leadership of Virginia Polytechnic Institute, will examine overall social and economic benefits of IPM implementation to the state's apple growers. We will be one of two states in the Northeast (New York is the other) to focus on apples. It is hoped that this study will provide information which will be useful in justifying further Federal support for IPM and in determining areas where program modifications are required to be more responsive to private sector needs. -7- m o iia- loa- Total calls = 14 19 25 29 3 6 10 13 19 24 1 7 10 14 21 26 1 8 12 19 22 26 9 19 31 April May June July August DATES Table 1. Code-a-phone use. Northeast and Western regions, 1983. -8- Table 2. Percent insect injured fruit in on-tree surveys of 48 IPM commercial orchard blocks. 1983^ Insect pest Tarnished plant bug . 2.52 San Jose Scale 0.49 European apple sawfly 0.41 Fruitworms 0.38 Plum curculio 0.17 Leafrollers 0.07 Apple maggot 0.03 Codling moth 0.00 Total Injury - Direct Pests 4.07 White afple leafhopper 0.22 Sooty mold 1.06 Total Injury - Indirect Pests 1.28 ■^Data from 38 blocks receiving private IPM scouting/consultant services from New England Fruit Consultants, Mr. Glenn Morin and Dr. Roberta Spitko. Samples consisted of 50 fruits per tree on 6-16 trees per block . Data from 10 other commercial blocks collected by Extension IPM staff. Samples consisted of 100 fruits per tree on 4-10 trees per block. 9- VARIATIONS IN TREE FORM IN AN EIGHT-YEAR-OLD SPUR-TYPE McINTOSH PLANTING C.G. Embree Agriculture Canada, Kentville, N.S. Editor ' s Note. The growth habits of Maaspur and Morspur trees are variable in Massachusetts. Thus, it is of interest to note that the same difficulty is being encountered with Starkspur Ultra Mac under Nova Scotia conditions . Nova Scotia apple type strains of commer size control is provid rootstock such as the can be used. These tr adopted 155 (14 x 20) seedling stock that ha and orchards in Nova S other seedlings, hardy tosh and Cortland. growers have a keen interest in the spur- cial apple cultivars. When considerable ed by the cultivar a more vigorous reliable locally grown Beautiful Arcade seedlings ees are not expected to outgrow the widely planting system. Beautiful Arcade is a s performed well in experimental trials cotia, being productive, smaller than many and a promoter of early yields with Mcln- Early indications of spur-type variants of Mcintosh from B.C. coincided with the development of a mother or- chard for the production of virus-free, true-to-name propagation material by the Nova Scotia Fruit Growers Association. Following in- vestigations of the various strains it was decided that the Dewar strain was most appropriate for this region. Negotiations with Mr. Dewar led to his forwarding a sample of scion wood to the Re- search Station for testing with possible inclu- sion in the mother orchard . Fig. 1. Dewar Mcintosh on Alnarp II in P. Van Oostrum Orchard planted in 1974 exhib- iting spur- type growth habit. Photo taken May, 1983. -10- Thc scion wood was grafted on Alnarp II roots at about 14" above the rootzone and grown in a nursery for one year. They were planted in a growers' demonstration trial in the sprini; of 1974. Trees were spaced at 15 x 22 at 50 trees per row in two adjacent rows. Early productivity has been good, as have been fruit color and size, when compared with other trees in the block. However, the strain has since been sold to Stark Brothers Nursery and re- leased as Starkspur Ultra Mac. Variation in growth habit has become obvious in the Nova Scotia planting (Figures 1^2) In 1983 trees with considerable branching and Fig. 2. Dewar tree in same block as shown in Figure 1 but with standard type growth habit (non-spur) . side shoots represented 21% of this plant- ing. Forty-six percent of the trees had typ- ical spur-type growth habit with virtually no side branches on the main limbs. The re- maining 33% of the trees had some degree of spur-type char- acter but some side branching was also present Detailed records of the number of spurs per meter of growth and th amount of extens growth will be recorded in 1984 prior to pruning e ion Reports of variation in spur-type tree from have been observed in other strains and cultivars in Nova Scotia orchards but no ratings have been done at this time. It is of interest to note that some trees in this block had little or no bloom in 1983. This is also true of Idared on MMlll and Spy on M26. It should be noted that the soil in this planting is quite coarse and excessively drained. This coupled with the very dry harvest season and heavy crop in 1982. appears to have accentuated an inherent biennial bearing tendency. Concerns of this tendency in the spur types are described in 1973 publication titled, "Spur-Type Apple Trees" and is available from the author. -11- HEIGHT CONTAINMENT ON SPARTAN AND IDARED TREES William J. Lord and Anthony W. Rossi Department of Plant and Soil Sciences In the January/February, 1980 issue of FRUIT NOTES we dis- cussed our progress with height containment of Spartan and Idared trees on M7a rootstocks. The objective of this demon- stration was to answer 2 questions: (1) What is a suitable pruning method for containing tree height?, and (2) What is the influence of height reduction on yield? Below we have: (1) summarized previously reported findings through harvest in 1979, (2) included our data and observations for the last 3 years, and (3) described containment pruning. Summary of Previous Findings Through Harvest, 1979 Limb rotation in the top third of the crown of Spartan and Idared trees on M7a rootstock was a suitable procedure for con- taining tree height. The pruning demonstration was initiated in February, 1976, and after dormant pruning in February, 1979, the average height of the control trees was 2.5 feet greater than that of the height- restricted trees. In spite of the height difference, yields were not consistently reduced from 1976 through 1979 on the height-reduced trees (Table 1) . Table 1. Influence on yield from height reduction of Spartan and Idared trees . Year Spartan^ Height reduced control Idared' Height reduced control 1976 1977 1978 1979 1980 1981 1982 Cumulative yield 6.0a 4.0b 10.4b 9.6h 6.5a 14.0a 13.1b 64b w Bushels/tree 8.0a 5. 3a 12.5a 12.2a 6. 3a 16.3a 14.4a 76a 6.2a 7.5a 4.1a 4.8a 10.2a 12.4a 8.9b 11.4a 8.2a 9.5a 9.3b 11.7a 14.2b 15.2a 61b 73a y Trees planted in 1964; trial started in February, 1976. T Tree height 3/79: Control, 11.4 ft.; height-reduced trees, 8.9 ft. Height 3/82: Control, 12.5 ft.,; height-reduced trees, 8.5 ft. Tree height 3/79: Control, 10.6 ft.,; height - reduced trees, 8.3 ft. Height 3/82: Control 11.8 ft.; height- reduced trees, 8.1 ft. Means in any row for each variety followed by different letters are significantly difference at odds of 19 to 1. w 12- Results Through Harvest of 1982 and Conclusions Containment pruning to restrict tree height continued to be successful. The height difference (measured at top of central leaderj between the control Spartan and Idared trees and the height-restricted trees of these varieties now averages 4.0 and 3.7 feet, respectively. Although the influence of height restriction on yield still is not consistent (Table 1) , the cumulative yields for the 7 years have been 12 bushels less per tree on the height-restricted trees. The harvest crew has expressed its preference for the height-restricted trees but the yield reduction may be unaccept- able to most growers. Theoretically, yields per acre of the height-restricted and control trees would be similar if the shorter trees were spaced 20% closer. For example, the trees in this trial are spaced 20 feet x 30 feet (72 trees/acre) . To increase tree numbers by 20% (86 trees/acre) one would plant the trees at 18 x 28 foot spacing. Containment pruning will work on many varieties but certain varieties are much more vegetative than others. We have en- countered no difficulty in maintaining the Idared and Spartan trees on M7 at 8.3 feet and 9 feet, respectively. However, tree height of 9 feet is too low for the innate vigor of non-spur Delicious on M7 at our Horticultural Research Center. In con- trast, spur-type trees of Delicious on M7a could be easily maintained at 9 feet (height of central leaders) . Procedures Suggested to Contain Tree Size 1. Branches that crowd those of adjacent trees will have to be removed or cut back to a weaker side branch. (Cuts made only to maintain the desired outer profile of the tree com- pounds rather than alleviates tree containment problems. Such cuts stimulate vigorous growth and by the end of the next growing season, the limb may extend as far as the original branch did before shortening, and may cause more shading within the tree than did the original uncut branch.) 2. Maintain conical tree shape by removing large limbs in the top third of the tree or cutting them back to a very much weaker side branch. 3. Initiate a limb rotation program in the top third of the tree by retaining weak branches or spreading desirable water sprouts, which in turn may have to be removed when they be- come too large. 4. Reduce the height of excessively tall trees by cutting them back to a strong outward growing lateral branch originating at a lower level on the leader. -13- 5. Frequently a strong scaffold branch with a narrow crotch angle develops in the upper third of the tree. If this branch is not removed or its growth is not restricted, the tree will become a multiple leader tree. Trees of this type are much more difficult to prune when practicing containment pruning or lowering tree height. 6. Delicious trees are subject to weak crotches, and branches are prone to develop in whorls and to droop. The ends of drooping branches should be removed back to a lateral grow- ing in a somewhat upright position. This will shorten and stiffen the branches. The tip of the lateral on a pruned drooping branch should be higher from the ground than any other portion of the branch. This should reduce the problem, of suckering. ********** POMOLOGICAL PARAGRAPH William J. Lord Department of Plant and Soil Sciences Increased Interest in Cherry Growing. Interest in cherry grow- ing has increased in Massacnusetts because of labeling permitting use of Mesurol* for repelling birds. While sour cherries are relatively winter hardy, sweet cherries may be severely injured, if not killed, by low temperatures. However, sweet cherries can be grown successfully with limited amounts of nitrogenous fertilizer. To eliminate or reduce injury to sweet cherry trees caused by low temperatures, the soil under the trees should not be cultivated. Sour cherry trees are smaller than sweet cherry trees and are better suited for U-pick operations. At this time we cannot recommend the use of dwarf rootstocks for either sweet or sour cherry trees. Several sweet cherry varieties you may want to consider are Emperor Francis, Schmidt, Hedelfingen and Windsor. Montmorency is the most popular sour cherry variety; other varieties are EArly Richmond, English Morello, North Star, and Meteor. North Star and Meteor produce much smaller trees than the other varieties a Trade name 14 RESPONSE OF INTERSTEM TREES TO PLANTING DEPTH 1 2 William J. Lord and Joseph Costante The responses of Empire, Rogers M Oregon Spur Delicious trees on M9/MM planting depth were investigated in at the Green Mountain Orchards, Putn Joseph Costante, Extension Fruit Spe author. The planting depth treatmen line approximately 2 inches below th union; (B) the soil line at the mid- and (C) the soil line approximately piece/variety union (see diagram bel the trees was 7 inches. The i'nforma findings at the completion of the st cintosh, Macspur and 106 or M9/MM111 to an experiment initiated ey, Vermont in 1976 by cialist and the senior ts were: (A) the soil e stempiece/rootstock section of the M9 stempiece; 2 inches below the stem- ow) . The stempiece on tion below summarizes the udy in November, 1982. variety SOIL LINE Planting depth A Planting depth B Planting depth C -15- Cultural Problems. Tree training difficulties were experienced particularly with Empire because the central leader lost its dominance. Leader leaning, which was corrected by staking, appears assoc- iated with the growth characteristics of Empire on interstem trees on M26 rootstock rather than due to cropping. None of the trees needed staking because of poor anchorage. The burrknots on the M9 stempieces on trees particularly at the (A) and (B) (the soil line at the mid-section of the stem- piece) planting heights were the entry sites of apple bark borer larvae in 1981. These were eradicated manually by probing for the larvae with a knife as well as scraping with a wire brush. Observations here, and at other locations have led us to conclude that the problem is associated with the use of mouse guards made of plastic which impede adequate coverage of pesticide sprays on the tree trunks. Crovvfth and Yield Burying or partially burying the stempiece tended to decrease the number of root suckers and increase the trunk cross- sectional area (TCA) and yield efficiency, but did not affect tree height and spread. Trees with the stempiece exposed had smaller trunks than those with the stempiece buried, but trees with the stempiece partially exposed did not differ in TCA from those at the other planting depths. Trees with the stempiece exposed produced the most root suckers regardless of the cultivar/inter stem/rootstock combination. These findings support the claim of Carlson in Michi- gan that deeper planting reduces the tendency of interstem trees to produce root suckers. Since root suckering was most severe when the stempiece was exposed, the question was posed whether the amount of suckering affected tree growth. There was a negative correlation between number of suckers and trunk circumference (r = -.15, p = .02). Because tree size varied across rootstock and cultivars, each rootstock and cultivar were evaluated separately. The number of suckers correlated negatively with trunk circumference for M9/MM106 (r = -.23, p = .01) and the Macspur (r = -.33, p = .01) and Mcin- tosh (r = -.48. p = .001). Ferree in Ohio reported a positive correlation between number of root suckers and trunk circumference on interstem trees with the lower union of the stempiece 5 cm above the soil line. -16- The trees were slow in coming into production partly due to poor tree quality at planting and poor growth in the orchard. The first crop was harvested from the Empire, Macspur, and Mcintosh trees in 1980 and from Oregon Red Spur Delicious in 1981. Thus, the yield data was still inadequate at the completion of the study in 1982 for a good evaluation of the influences of planting depth on yield and this problem was confounded by the fact that the orchardist inadvertently harvested the Macspur and Mcintosh in 1982, Preliminary data for the Empire and Delicious show that trees with the stempiece exposed have produced less per TCA than those with the stempiece buried. Yield efficiency of trees with the stempiece partially exposed was not different from the others. Both the growth and limited yield data support the suggestion that interstem trees will be weakened and bear less if the stempiece is above the soil line. The rootstock and/or cultivar had more effect than planting depth on several factors. Tree spread was greater for trees on M9/MM106 than on M9/MM111. Delicious trees were smaller and had less bloom than the other cultivars. Macspur had less branch spread than Mcintosh or Empire. Roots from burrknots were present on all but 3 trees with the stempiece buried. Conditions were considered very favorable for rooting from the burrknots because the soil had been heavily mulched with hay since 1980 and rain was ample for optimum grov;th. Never- theless, 26% of the stempieces had only short, fibrous roots less than 18 cm in length. Since the trees were not dug up, the original roots could not be observed but it does seem that this rooting may be too limited to entirely replace the original roots as was observed by Rogers and Parry in England. Rootstock and cultivar had no influence on the amount of rooting. After 7 growing seasons, interstem trees of Oregon Spur Red Delicious are smaller and less productive than similar trees of Empire, Macspur and Rogers Mcintosh. It appears that because of the upright branching nature and small leaf surface, the spur-type Delicious strain is slow to develop. Summary Production of root suckers by interstem trees can be reduced by deeper planting. Our limited observations lead us to conclude that interstem trees will require more care than those on vigorous size-controlling rootstocks and that the stempiece is a site for possible difficulty with weather, rodents, insects and disease. Further testing is needed before we can recommend planting of inter- stem trees other than for trial. -17- USING W CLIPS TO TRAIN FRUIT 1 TREES George M. Greene' Associate Professor of Pomology Pennsylvania State University Fruit Research Laboratory, Biglerville, PA Most frui with the use o pins to spread shoots of upri vars. The use help good crot and will help becoming trapp leader and the t growers are familiar f spring-type clothes young 2-4 inch long ght growing apple culti of this technique will ch angles to develop prevent dead bark from ed between the central lateral scaffold limbs Unfortunately many upright grow- ing cultivars need additional branch spreading in years 3 through perhaps 6. Most fruit growers are familiar with the use of wooden spreaders (with nails in the ends) to spread laterals away from the central leader into a more horizontal position. This spreading tends to reduce the vigor and increase the fruitfulness of the spread branch. In addition, if lateral branching can be encouraged on the spread scaffold limbs, trees will tend to be more productive since more sunlight can be intercepted by the enlarged tree canopy. The author saw VI clips being used in England in 1979 to spread branches but no source of the clips in the U.S. was known. However, hop growers in Washington use this style of clip to help construct the string trellises to support hop 1 Pennsylvania Extension Hort Series II: permission of the author. 140, 1983. Reprinted by •18- plants. For fruit trees, the clips can be used to hold plastic ba'ler twine in the ground to spread scaffold limbs and to hold erect, young trees that have leaned. A loop is placed in the end of the twine and the loop is placed onto the W clip that has been placed on the end of the applicator. In the spring when the soil is moist, the ^^ clip can fairly easily be forced 6-10 inches into the ground. The plastic baler twine can then be used to straighten up a tree trunk or to spread a branch. The advantage the W clips over wooden spreaders is that the point of application of the spreading force can be placed any- where along a limb. By moving the point of spreading force further out on the limb, some of the spreading action can be placed onto the limb itself and less placed on the crotch. The flexibility in being able to move the point of attachment seems to be a major advantage over wooden spreaders. In addition, for those growers interested in spreading peach and other Prunus species, the W clips and baler twine have an advantage in that no nail holes are made in the bark where cytospora canker could enter the tree. On the negative side, the twine coming out of the ground up to the branches must not be hit with equipment. Using an offset nozzle at the end of the weed boom should allow herbicides to be applied without hitting the trees. Supplies : Source : W clips - 2000 Applicator - 4 per carton, 22 lbs lbs. Hop Growers Supply Co., Inc. PO Box 325 Toppenish, Washington 98948 Attn: Jim Owens Phone: (509)865-3731 Cost 1 1 carton (2,000 w clips) 1 clip applicator U. P. S . on cl ips U.P.S. on applicator Handling $18.40 10.90 10.06 3.51 10.00 $52.87 Editor's Note: Cost of supplies based on quotes received July, 1983 At press time we were informed that Orchard Equipment and Supply Company, Conway, MA 01341 sell W clips and twine. -19- EFFECTS OF MINERAL NUTRITION ON KEEPING QUALITY OF CA McINTOSH IN MASSACHUSETTS W.J. Bramlage, M. Drake and S.A. Weiss Department of Plant and Soil Sciences In the previous issue of FRUIT NOTES (Fall Issue, 1983) we reported results from a four-year study showing relation- ships of mineral nutrition to keeping quality of Mcintosh apples kept in air storage. We now have the results from this study showing how mineral nutrition is affecting keeping quality after CA storage. As described previously, 172 orchard blocks were sampled over a 4-year period. One bushel of apples from each block was stored in CA at 31 Oj, S% CO2, and 36°F for approximately 8 mon- ths, then kept 70-80 degrees F. After 1 day firmness was measured and after 1 week the apples were examined for the occurrence of breakdown, rot, scald, and bitter pit. However, scald and bitter pit were too infrequent on these samples for any relationships to mineral concentrations in the fruit to be established. Maintaining fruit firmness is vitally important to quality of Mcintosh after storage. In these tests firmness was measured at harvest and after storage. As we reported previously for air storage, mineral concentrations had no relationship to firmness after CA; all correlation coefficents were non- significant . Fruit maturity at harvest and postharvest conditions, not mineral concen- trations, are what regulated fruit firmness in these tests. Although the fruit were stored 3 months longer in CA than in air storage, the CA samples generally developed less breakdown and rot than did- the air-stored samples because CA greatly slows down changes in apples. Therefore, with smaller amounts of these problems, relationships of minerals to them tended to be lower than were the relationships to the same problems after air storage. This is illustrated in Table 1. Correlation coefficients express these relationships in such a way that the larger the number (whether it is positive or negative), the closer is the relationship. It can therefore be seen that in nearly every case, the relationship be- tween a mineral and a problem is somewhat less for CA-stored than for air-stored samples. Table 1 shows that mineral concentrations affected the occurr- ence of rot after storage. In this relationship, P concentration was more important than that of Ca. However, rot can generally be controlled by use of fungicides in postharvest treatments, which were not used in these tests. -20- For breakdown after CA-storage, Ca was twice as important as any other element. This relationship is shown graphically in any otner element. inis reiatiunsnip ib snown grapnicaiiy in Figure 1, where the percent ofthe fruit that developed breakdown after CA storage is plotted in relationship to the Ca concentration in the sample at harvest. This graph is virtually identical to the one presented in our previous article on Air-stored fruit. As pointed out then, samples very low in Ca (e.g., less than 130 ppm) almost always developed breakdown in more than 101 of the fruit, while samples high in Ca (e.g., more than 175 ppm) almost never developed breakdown in 10% or more of the fruit. Between these extremes, the lower the Ca the more likely the fruit were to develo excessive amounts of breakdown, although other factors probably determined whether or not these intermediate-Ca apples actually developed breakdown. These results show once again the importance of Ca in preventing breakdown of Mcintosh apples during and after long-term storage. Table 1. Correlation coefficients relating mineral concentrations in apples at harvest to occurrences of internal breakdown and rot after storage in air at 320F for 5 months, or after CA storage at 360F for 8 months. Element Breakdown after Rot after A ir storage CA storage Air storage ■ CA storage Calcium -.40*** -.37*** -.19** -.14* Phosphorus -.33*** -.16* -.31*** _ 27*** Magnesium -.22** -.14* -.22** -.14* Potassium + .12 -.13* .00 .00 Nitrogen -.35*** -.18** + .06 -.17* Asterisks indicate the statistical odds that a real relationship exists : Odds of 19:1; **Odds of 99:1; ***Odds of 999:1 -21- 100 o Q < LJ m q: UJ UJ o cr 80 60 - 40 - r --.37*" • \» ••#i^» • • • • •*. •• — -:~- , •• • * *^ #••• J • «» « » 100 130 160 190 CALCIUM, OUTER CORTEX TISSUE(ppm) 2 50 Figure 1. Relationship between occurrence of internal breakdown in Mcintosh apples after CA storage and the concentration of calcium in the samples at harvest. Points represent 172 samples taken over a 4-year period. ********** POMOLOGICAL PARAGRAPH V/illiam J. Lord Department of Plant and Soil Sciences Differences between M7 and M7a. Occasionally we are asked what is the differences between Mailing (M) 7 rootstock and M7a rootstock. The rootstocks are similar except that M7a has been selected for its freedom from the so-called "latent viruses". These are viruses that are commonly present in apple varieties and include stem pitting, chlorotic leaf spot, platycarpa scaly bark and apple stem grooving. 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 49 No. 2 SPRING ISSUE, 1984 Table of Contents Heading Cuts on Apple Trees Reduce Yields Pomoiogical Paragraph — Soil and Plant Tissue Testing Recommendations for Fertilizing Apple Trees and Increasing Calcium Content of Fruit Care of Trees on Arrival from the Nursery Practicality and Longevity of Hardpan Modification The Apple Maggot in Massachusetts, Michigan and West Coast States Gala — An Apple Variety Worthy of Trial The Use of Promalin to Improve the Shape of Delicious Apples Freedom: A New Disease-Resistant Apple Performance of Disease-Resistant Apples Gray Mold on Strawberries Issued by the Cooperative Extension Service in furtherance 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. M ^■^S> ^^^^^^^^^^^^H y ^v^^H^t JL ^^H ^P^M M B B HEADING CUTS ON APPLE TREES REDUCE YIELDS W.J. Lord, R.A. Damon, Jr., J. Sincuk, and K.E. Slossepl University of Massachusetts In the past there was a general agreement in most fruit growing areas in the East on the basic principles and procedures recommended for training young apple trees. A central leader or modified central leader tree was usually favored, such a tree had the scaffold branches spaced 8 or more inches apart and spirally around the leader. To develop this tree thinning cuts were most often used; heading cuts were suggested only when necessary to balance the length of the scaffold limbs. We define pruning cuts as follows: Heading, reducing the length of 1-year-old wood by 25%; Stubbing, reducing the length of the branches with cuts made into 2-year-old or older wood; Thinning, remov- ing an entire shoot or branch at its junction with another shoot, branch or leader. Since the early 1970's pruning by heading cuts increased drastically in apple orchards throughout northeastern United States. On young, non-bearing trees, heading cuts are being used to stiffen branches, increase the length of the extension shoot of structural limbs, and particularly to increase secondary branching from structural limbs. In bearing orchards branches are headed to control size and shape of trees particularly when too closely spaced. The cuts are made with hand held tools and machines. During the last 7 years we have made extensive studies of growth and fruiting responses of Redspur Delicious trees to heading cuts. Our findings are summarized below. Methods and Materials The trees used in this experiment were planted in 1976, during the first growing season pruning was limited to the removal of branches arising within 18 inches of the ground. In March, 1977 the following pruning treatments were established and continued through 1982: (1) control[(conventional) Fig. la]; (2) thinning limbs to develop tiers and dormant heading cuts on I-year-old wood [(Tiers and Heading) Fig. IB]; and (3) minimum pruning (Slender Fig. 1A. Fig. IB. Two year old tree being pruned by standard prun- ing procedures. The lowest limb should be 18 to 20 inches from the ground, all others spaced 4 to 8 inches apart vertically on the trunk and each one about 90° around the trunk from the one below it. Two year old tree being pruned as suggested by the USDA. It has 2 layers of limbs. The leader will be headed annually [heavy marks ( — ) indi- cate heading cuts] . The one year old wood on the branches is headed annually until branches on which this wood is borne start to fruit. ^Extension Fruit Specialist, Statistician, and Technical Assistants, respectively. -2- Spindle). All trees were trained to the central leader, free-standing pyramidal form. Limbs that required positioning were spread to a 45° to 60° angle to promote strong crotches and early bearing. Procedures followed in training trees to the Conventional system were as follows: (1) removing branches with narrow crotch angles; (2) removing undesirable branches to eliminate whorls and thus permitting only 1 branch to develop at a given level; (3) main- taining the dominance of the leader by suppressing or removing competing leaders; and (4) restricting too rapid development of certain structural (scoffold) limbs by stubbing- back to an outward horizontal shoot or branch. The objective was to develop a central leader tree with structural limbs symmetrically arranged around the vertical axis of the leader and spaced 8-12 inches verticallywith none directly above one another. Most cuts were thinning and stubbing cuts. Trees trained by the Tiers and Heading system received heading cuts on 1-year-old wood each dormant pruning season, starting in March, 1977, to shorten by 25% (a) the extension shoot of the central leader; (b) the extension shoot of each structural branch; and (c) each lateral shoot longer than 20 cm on structural branches (Fig. 2) . These cuts MOW TO GET IMt HIGH DENSITY T«EE OFF TO A GOOD STAIT. HEAVY MASKS SHOW WHEII PRUNING CUTS SHOULD «E MADE 1-y«ar-otd itttion R«mov« oil compiling ihooti Hcod bock l«r- minal ihoot 3-y»or-old lethoo Sel«(t and h«od lof«rol bron were made to encourage development of lateral shoots which eventually became structural branches originating from the central leader or secondary branches as suggested by D.R. Heinicke and illustrated in Fig. 2. The lateral shoots on the central leader were thinned to create tiers of structural limbs spaced 20 to 24 inches apart. The headed wood generally produced a cluster of vigorous shoots directly behind the cut during the following growing season. Each summer when these shoots were 4 to 6 inches long, one was selected for the permanent extension shoot and 2 competitors were removed by hand to simulate the growth on a non-headed branch and to prevent excessive proliferation of the extension shoots. -3- On Slender Spindle trees the strong vertical leader was removed during dormant pruning and a weaker, upright-growing competitor was retained for the new extension shoot to weaken growth in the top of the tree. All lateral branches developing from I Fig. 3. Structural branch from 'Redspur Delicious' trees on which no heading cuts have been made. The secondary branching is shorter than on the branch shown in Fig. 4 but it has more fruit spurs and has been more productive. -4- the central leader were utilized unless they iiad narrow crotcli angles or competed with the central leader. Fig. 4. Structural branch from 'Redspur Delicious' tree on which heading cuts were made annually for 4-consecutive years. The white lines mark where heading cuts were made. The bearing surface on this limb is slightly greater than on the "typical" non-headed branch shown in Fig.3 but the procedure eliminated many potential fruiting spurs. -5- Results and Discussion Heading all of the 1-year-old shoots during dormant pruning followed with removal of 2 shoots directly below each heading cut during the growing season to leave 1 terminal extension shoot, increased lateral growth some years but not others (Fig. 3 and 4). However, yields were reduced on the Tiers and Headed trees in comparison to the Conventional and Slender Spindle Trees (Table 1). Table 1. Effects of pruning systems on tree size, and yield of redspur Delicious trees on M26. Variable Year Conven- tional Increase in trunk circum. (cm) . 1977 3.73aZ 1978 3.62a 1979 2.74a 1980 3.04a 1981 3.32a 1982 2.50a Yields (bushels) 1979 0.2ab 1980 0.8a 1981 l.Oab 1982 3.4a Cumulative Yield (bushels) 1982 5.4a No. scaffold limbs/tree 1982 13a Tree height (ft) 1982 10.8a Tree spread (ft) 1982 9.6a Pruning Treatment Tiers & Slender heading spindle 3.06b 3.41ab 3.44a 3.72a 3.04a 2.68a 3.13a 3.20a 3.10a 3.54a 3.09a 2.48a 0.1b 0.3a 0.4b 0.8a 0.8b 1.2a 2.6b 3.5a 3.9a 5.8a 2a 13a L7a 10.7a 8.2b 10.0a ^Mean separation in rows by Duncan's range test, 5% level. The decreased productivity of the Tiers and Headed trees was clearly a result of the heading-back cuts since the number of structural limbs per tree and tree size at the completion of the study, with the exception for branch spread, were smiliar among treatments (Table 1). The spread of the Tiers and Headed trees was less than that of Conventional and Slender Spindle trees because the branches were more up- right due to lighter cropping. Heading cuts reduced the length of 1-year-old wood, forced some lateral buds to produce vigorous shoots rather than flower buds; and removed the most productive section of the wood because the apical sections have more blossom clusters and fruit than the more basal sections of wood. -6- Our findings agree with a similar study conducted by Lord and Sincuk (2) with Spartan apple trees and with experiments of Elfving and Forshey in New York state (1). The latter workers used heading cuts of various severity on vigorous 1-year-old wood of a non-spur Delicious. Increased severity (removal of a greater fraction of 1-year-old wood) produced increased shoot growth from 1 and 2-year old wood. Fruitfulness decreased as severity increased. It is of interest to note in Table 1 that yields on the Conventional and Slender Spindle trees were comparable. However, the annual practice of removing the strong extension shoots of the central leader and using a weaker upright growing competitor as the new extension shoot on Slender Spinle trees to produce a zig-zag growth pattern was discontinued after the 1979 dormant pruning season due to difficulty in maintaining leader dominance. Trees on M26 seem to react more to unfavorable growing conditions tha those on more vigorous- size controlling rootstocks and the central leaders often require support but we also encounter- ed problems with apical dominance with Spartan trees on IV17a rootstock trained as Slender Spindles (2). These results and observations in a trial with Gardiner Delicious on MM106, IVIYa and M26 suggest that pruning the leaders to develop a zig-zag growth pattern and to reduce growth should be delayed on free standing trees until the leader nearly attains the height desired for the tree. Summary In todays economic climate of high interest rates growers must obtain a return on capital investment as soon as possible. The key to early fruiting is the planting of a well- feathered (branched) tree and the rapid development of a productive bearing surface. The grower has little control over the quality of the nursery stock, except to reject inferior trees; but has no one to blame but him/herself if early yields are reduced by improper pruning, especially an excessive number of heading cuts. Emphasis should be on training rather than pruning young trees since fruiting is the key to control of vegetative growth. Certainly, some pruning is necessary but the majority of cuts should be thinning rather than heading cuts on trees of all ages. Thinning cuts usually improve light penetration into the tree, thus increasing carbohydrates that encourage flower bud initiation. Heading cuts encourage vegetative growth which may increase shading in the interior of the tree and reduces fruitfulness. Fruiting decreases from the exterior to the interior of the tree and much of the wood 4 years or older may have few, if any, flowering spurs. Thus, the 2- and 3-year-old wood is of great importance to the fruitfulness of apple trees and should be subjected to only modest pruning using thinning rather than heading cuts. Literature cited 1. Elfving, D.C. and C.G. Forshey. 1972. Growth and fruiting responses of vigorous apple branches to pruning and branch orientation treatments. J. Amer. Soc. Hort. Sci. 101:290-293. 2. Lord, W.J. and J. Sincuk. 1980. Progress report: Pruning effects on growth and fruiting of Spartan apple trees. Massachusetts Agr. Ext. Serv. Fruit Notes 45(5):l-8. -7- POMOLOGICAL PARAGRAPH William J. Lord Department of Plant and Soil Sciences Soil and Plant Tissue Testing. Occasionally we receive inquiries from persons from other states about having leaf samples and/or soil samples analyzed at the Suburban Experiment Station in Waltham, Massachusetts. The service is avilable to all persons regardless of residence. To receive containers for soil and/or leaves, individuals desiring this service should complete and mail the following form with a check made payable to Soil Testing labor- atory. Send form and check to Suburban Experiment Station, 240 Beaver Street, Waltham, MA 02254. Soil is analyzed for pH and elements. Leaves are analyzed for 16 major and minor elements. Order form Please send me the following kits: Soil @ $5.00 each. Leaf sample @ $10.00 each. Enclosed please find $ . Name:_ Address _^ ^^^ zip -8- RECOMMENDATIONS FOR FERTILIZING APPLE TREES AND INCREASING CALCIUM CONTENT OF FRUIT William J. Lord and W.J. Bramlage Department of Plant and Soil Sciences NITROGEN (N) Many apple orchards are established in sod although we suggest eliminating the sod by plowing and disking or if the soil is extremely stony, by herbicides. If the site has been properly prepared and pH and nutritional problems have been corrected, no fertilizer may be needed the year of planting. However, trees planted on hay fields or pastures without extensive land preparation should receive N. Those planted on land previously in forest generally should receive a fertilizer containing both major and minor elements. Non-bearing trees. Lime but not fertilizer or manures can be put in the planting hole with the roots. Fertilizer, a complete fertilizer, or one containing N, potassium (K„0) and minor elements, should be applied after a rain has firmed the soil around the roots of the newly planted tree. Fertilize at the rate If 1/3 - 1/2 pound of ammonium nitrate (33% N) or its equivalent by spreading lightly in a wide circle around the tree (8 to 12 inches from the tree trunk). 12 inches from the tree trunk). Table 1. Fertilizers, their nitrogen (N) content, and pounds that must be applied to equal a certain amount of actual N. Fertilizer % N Approximate pounds that must be applied to be equivalent to the following pounds of actual N. 0.3 lb 0 .6 lb 1.0 lb 2.2 3.0 6.3 6.3 20.0 12.5 10.0 It is extremely important to obtain good growth on the trees in their non-bearing years. However, water rather than N may be the limiting factor some years on some sites. N is usually applied at high rates to stimulate growth of trees while non-bearing. For example, at our Horticultural Research Center in Belchertown, MA, young, non-bearing trees may receive 0.3 - 0.6 lb of actual N/tree whereas bearing trees receive 0.0 - 0.3 lb of actual N/tree. After the year of planting, fertilizer, either nitrogen (N) alone, a complete fertilizer, or a fertilizer containing N and potassium (K„0) and minor elements, should be applied 3 to 4 weeks prior to bloom and at a rate of 1/3 pound of ammonium nitrate or its equivalent for each year of age. Urea 45 0.7 1.3 Ammonium nitrate 33 0.9 1.8 Sodium nitrate 16 1.9 3.8 Calcium nitrate 16 1.9 3.8 5-10-10 5 6.0 12.0 8-16-16 8 3.8 8.0 10-20-20 10 3.0 6.0 -9- Reduce or omit N on young, vigorous Mcintosh trees when they start to bear fruit, if the trees appear very vigorous, to avoid excessively large, poorly colored apples. With this cultivar and all other cultivars, start participating in the Leaf Analysis Program when the trees start to fruit in order to determine the fertilizer requirements of the trees. (Information concerning the Leaf Analysis Program and specific details on orchard fertilization can be obtained from your County Extension Service.) Bearing trees. There is no way to go broke faster than by producing high yields of soft, green apples that bruise easily and keep poorly. On older, bearing Mcintosh trees, N levels of 1.8 - 2.0% appear optimum. If the leaf analysis shows that the N level is above 2.0%, adjust the fertilizer program according to tree vigor, productiveness and fruit color, as experience indicates. High leaf N levels fall very slowly even when no additional N fertilizer is supplied because large reserves of the element accumulates in the soil, sod and tree. Therefore, it may take several years to bring an excess N level down to the normal level. Our data shows that the total amount of N being applied is usually more important concern to fruit quality than whether the N is supplied by applying ammonium nitrate, sodium nitrate, calcium nitrate, etc. Fertilizer Placement Under Bearing Trees. The mass of the secondary root system of apple trees lies between 2 and 3 feet in depth and within half the distance from the tree trunk and its dripline. This explains why our studies show that more efficient use of N and other elements can be obtained by application within a limited area closer to the tree trunk rather than by application near the tree's dripline or a broadcast application under the entire spread of the tree. Recent studies in England show that under herbicide-strip management and with a wide in-row spacing, as in common in Massachusetts, there was little N uptake from the grassed alley. POTASSIUM (K) Generally N is the only element required by non-bearing trees. However, experience has shown that K is needed by non-bearing trees on land cleared from forests and on sites with sandy or gravelly soil, or very acid soil. Not all horizons in the soil are equally able to supply nutrients to the tree. The concentration of most elements are highest at the soil surface and decrease with depth, but the rate of decrease differs between elements. For example, there is a strong vertical difference in K status in soil, K being highest near the surface. Under drought conditions the permeability of the roots to water uptake decreases very rapidly; reduction in water permeability reduces the uptake of all ions. In Massa- chusetts we are particularly concerned about K and B deficiency and reduced fruit size in drought years as was experienced during the summer of 1983. Total K absorbed and the total dry matter produced is similar for fruiting and non- fruiting trees of the same size but in heavy-cropping trees K is translocated into the fruits. Thus, the demand of a larger crop for K is great and both the tree and fruit may be deficient in this element. -in- Tree requirements for K. K„0* needed to meet the K requirements based on potential yields are as follows: (a) less than 15 bushels: 1.3 lbs/tree; (b) 15 to 25 bushels: 1.3 - 2.7 lbs/tree; and (c) more than 25 bushels: 2.7 - 4.3 lbs/tree. The K„0 requirements can be supplied by applying muriate of potash, a "complete" fertilizer or Sulpomag**. Increasing the K level in the trees will further reduce IVIg. Therefore, Sulpomag is suggested when trees are low both in K and Mg because the elements must be kept in balance. This fertilizer contains not less than 21% of potash (K2O), nor less than 53% of sulfate of magnesia. Mature trees below normal in K will require 200-300 of K or 600 lbs of Sulpomag per acre. FERTILIZERS SIMILAR TO SULPOMAG MAY BE AVAILABLE AND EQUALLY SUITABLE. CALCIUM (Ca) If Ca is below normal, continue to apply 3 tons of limestone per acre every 2 to 3 years. Where high magnesium lime was used in the last application, the use of a more soluble high Ca, low Mg lime (5 - 7% MgO) will act more rapidly and will provide more Ca. Apply foliar sprays of CaCl2, beginning 3 weeks after petal fall and repeat at 2 week intervals totaling 6 to 8 applications. Apply 6 pounds CaCl2 per acre per spray until mid-July. After mid-July apply 8-10 pounds per acre per spray. Continue foliar CaCl2 until fruit are ready for harvest. Use a technical grade of CaCl2 such as Allied Chemical Dow Flake, 77-80% CaCl2. Other brands may be equally suitable. Experience in Massachusetts has shown that CaCl2 can be combined with pesticide sprays. However, some growers have observed that the combination of Captan or Guthion (azinphosmethyl) 50 WP and CaCl2 may increase foliar burn. DO NOT MIX CaCl2 AND SOLUBOR SPRAYS! ALWAYS DISSOLVE CaCl2 IN A PAIL OF WATER and add this last, when the spray tank is nearly full, to insure that the CaCl2 is completely dissolvedbefore spraying begins. Foliar CaCl2 sprays may be applied as dilute (300 gallons/acre) or up to lOX concentration (30 gallons/acre) . In our research, apple flesh Ca was increased more by concentrated than by dilute sprays. CaCl2 sprays can cause burn of leaf margins. Foliar injury has been more serious on Mcintosh than on Delicious or Cortland. Apple leaves are less susceptible to CaCl2 burn after mid-July. Mcintosh growing on M7 may be more susceptible to foliar burn than those on standard rootstock. Weak or injured trees may be more susceptible to CaCl2 burn than healthy trees. To reduce the chance of leaf burn, DO NOT REPEAT A FOLIAR CaCl2 SPRAY UNLESS ONE-HALF TO ONE INCH OF RAIN HAS FALLEN SINCE THE LAST APPLICATION. We also urge growers to seriously consider supplementing CaCl2 sprays with post-harvest CaCl2 dips or drenches especially fruit intended for long-term storage. A postharvest Ca application is viewed as a food-additive process by the Food and Drug Administration. That agency has stipulated the "Brining Grade" CaCl2 containing 94% CaCl2 is acceptable for postharvest use. The technical flake CaCl2 commonly used for tree sprays is still acceptable for tree sprays, but it may not be used for postharvest treatments. Therefore, anyone wishing to use postharvest CaCl2 treatments must obtain the Briner's Grade material, which is now readily available from suppliers. * Potassic fertilizers are usually guaranteed in terms of their content of the oxide of potassium (K2O). The commonly used potash salts are the refined muriate or chloride containing 50-60% K2O. ** Trade name -11- Calc2 may be combined with scald inhibitors and fungicides in the post-harvest treatment solution. Cornell University has recommended the following mixture for postharvest treatment of Mcintosh: 21 lbs of CaCl2 per 100 gallons of water 1/2 lb of Benlate or 16 fluid ounces of Mertect 1 lb of Captan 1000 - 2000 ppm DPA We suggest that 1/2 quart of vinegar also be added to this mixture in 100 gallons of water. The vinegar neutralizes the CaCl2, which otherwise makes the solution alkaline. There is evidence that the alkaline solution may cause the fungicides to break down rapidly in solution, and the addition of vinegar can protect against their alkaline degradation. In use of postharvest CaCl2 drenches or dips, it is important to understand that little or no Ca enters the fruit during the treatment. The purpose of the drench is to leave a residue of CaCl2 on the fruit. Ca is slowly absorbed by the apple from the residue during storage. Therefore, the drench is never followed by a rinse, which would remove the residue. Furthermore, for Ca to be absorbed from the residue, the residue must not dry out. However, if the storage is operated at lesss than 90% relative humidity the residue may dry out and no Ca uptake will occur as a result of the drench treatment. We have encountered no difficulty from this residue when apples are removed from storage. It will be removed if apples are water-dumped, but even with hand-packed fruit no difficulty has been reported. CaCl2 drenches can cause fruit injury, which occurs as tiny black spots on the surface of the fruit. Generally, these spots are concentrated in the calyx cup of the apple and are not objectionable, although under some circumstances they may coalesce into more unsightly blotches or may occur at the lenticels on the cheeks. Do not exceed the recommended CaCl2 concentration, as risk of this injury escalates rapidly at higher concentrations. CaCl2 is also corrosive, so equipment should be thoroughly cleaned at completion of treatment. However, with appropriate rinsing corrosion should not be a concern. The purpose of the postharvest application of CaCl2 is to reduce the risk of breakdown, rot, and scald during but especially after storage. The recommended treatment will not make fruit firmer, but will improve their ability to hold up during marketing. Treatments will be of greatest benefit to mature fruit destined for long-term storage. Overripe fruit cannot be expected to benefit significantly from a CaCl2 treatment. MAGNESIUM (Mg) Mg deficiency is closely associated with very acid soils. The pH in most orchards is higher than 25-years ago because liming programs and the change from sulfur to organic fungicides; thus, Mg deficiency is now not common. Dolomitic lime (high Mg lime) is the least expensive source of Mg for orchards. It can be applied anytime during the year. If the Mg level in leaves is below 0.25% apply 3 tons/A of dolomitic lime to maintain a soil pH of 6.0 - 6.5. If the Mg level is below 0.20%, we also recommend 2 or 3 Epsom salt sprays at 15 to 20 lbs per 100 gallons dilute at approximately petal fall, first, and second cover. We suggest that the Epsom salt sprays be applied as separate applications. However, pomologists in other fruit growing areas in eastern United States believe that Epsom salts are compatible with most pesticides up to 15X concentration. 12- MANGANESE (Mn) Mn is the most frequently deficient element in apple trees. Mn deficiency should be corrected on trees showing considerable foliage damage. Although we have no definite proof, Mn deficiency appeared to be associated with excessive fruit drop on a few trees in orchard in 1977. Mn deficiency can be corrected by foliar applications of manganese sulfate or of a fungicide containing Mn. Apply manganese sulfate at about first cover at the rate of 3 lb per 100 gallons of water. If using a Mn-containing fungicide, 2 or 3 applications are necessary with timings about petal fall, first and second cover. BORON (B) B can be supplied to bearing apple trees either by foliar or soil applications. Use the most economical and convenient method. However, it is safest to apply all elements as a fertilizer except in emergency situations. Soil applications of boron should be applied to orchards every 3 years. The rate of application per tree vary with tree age and size. In low density orchards, apply 1/4 lb of borax (11.1% actual B) or its equivalent under young trees coming into bearing, 1/2 to 3/4 pound to medium age and size trees and 3/4 to 1 lb to large or mature trees. Be sure to note the percent actual B in the fertilizer being used to supply this element. B containing fertilizers vary from approximately 11 to 21% actual B. In medium and high density orchards (115 trees/acre or higher), it might be best to apply B on an acre basis. We suggest the following rates per acre of borax (11.1% actual B) or its equivalent: (a) trees 4 to 7 years of age - 12 lbs; (b) trees 8 to 15 years of age - 12 to 24 lbs; and (c) trees 16 to 30 years of age - 24 to 48 lbs. When the soil application of B is followed by a wet spring, it may be advisable to apply 2 foliar applications of B the following year. Many growers now rely on annual foliar applications of B. The usual practice is to add Solubor to the first 2 cover sprays. Fertilizer grades of borax may contain grit and should not be used in a sprayer. Mature trees should receive 4 pounds of Solubor per acre each year. Consequently, the goal is to apply about 2 pounds per acre in each of the 2 applications. For young orchards, the addition of 1/2 pound of Solubor per 100 gallons (dilute basis) to the first 2 cover sprays meets the B requirements of these trees. Reports of New York State indicate that sprays can be concentrated up to 8X with satisfactory results. Leaf samples from orchards treated with Solubor have indicated adequate leaf B levels but the fruit was deficient in this element. Whether or not B applied as a fertilizer more adequately meets the B requirement of apples than foliar applied B is not known to us. ZINC (Zn) Based on optimum levels of Zn established by Dr. Warren Stiles, Cornell University (See FRUIT NOTES 47(2):20-26, 1982) some of our orchards continue to be low in this -13- element. W. Stiles considers optimum Zn leaf levels to be 35 - 50 ppm with concentrations below 15 ppm being deficient. He has stated that "annual requirements for Zn are approximately 2 lbs per acre if applied as inorganic salts in dormant sprays or approximately 0.2 - 0.3 lbs of actual Zn applied as foliar sprays of EDTA chelates IT to 5 lbs/acre). Amounts of Zn required to correct severe deficiencies may be 4 to 5 times these amounts. Zn-containing fungicides provide some benefit but are not adequate to supply the total need." CARE OF TREES ON ARRIVAL FROM THE NURSERY William J. Lord Department of Plant and Soil Sciences A local nurseryman expressed concern last year about grower care of trees prior to planting. He was particularly concerned with storage of trees with apples and about soaking trees in water for 2-3 weeks. If trees from the nursery arrive in bad condition from drying in transit, pomologists years ago suggested soaking the entire tree in a brook or a pond for a day or two. We have seen no comments concerning the effect of soaking trees for longer periods of time! Due to the possibility of tree injury from the lack of oxygen, we suggest soaking the roots in water no longer than a day or two. Our recommendations for care of trees on arrival from the nursery are as follows: 1. Check the trees to determine if tree count and cultivar/rootstock and size agrees with order and to determine if injury to the trees might have occurred in handling and shipping. Do this where it is cool and the roots will not dry out. 2. If planting conditions are not suitable, open the bundles of trees and store them in a cool, well-ventilated area and be sure the roots are kept moist, or heal them in a shady area, or cover the roots with wet soil, peat or sawdust in an open shed. 3. DO NOT STORE trees with apples or where they have been stored. It is possible that residual ethylene in the storage atmosphere might break dormancy of the trees and when planted they may fail to grow properly or even die. Pear trees are especially sensitive to injury. 4. If the roots of the trees are dry, soak the roots in water for 2-24 hours prior to planting. -14- PRACTICALITY AND LONGEVITY OF HARDPAN MODIFICATION Peter L.M. Veneman Department of Plant and Soil Sciences About 40% of the soils in Massachusetts have a hardpan within 3 ft of the soil surface. Considering the fact that a large number of our orchards are located on drumlins (elongated or oval hills of glacial drift), I estimate that between 50 to 60% of the Massachusetts orchard soils have a hardpan within 3 ft depth. The presence of this pan is well known to most fruit growers as it often necessitates sub-surface tile drainage. The low water permeability is due to a high bulk density of the pan material. This often inhibits root proliferation as well, which may result in increased susceptibility to midsummer droughts and excessive frost heaving during the winter. Modern, size-controlling rootstocks seem especially sensitive to the presence of this hardpan. The dwarfing effect not only occurs above-ground, but is also evident from a less prolific root system as compared to that of standard rootstocks. In addition, size-controlling rootstocks such as M7a are in full production after about 10-12 years, while the standard trees take much longer to become productive. The longer time period permits the establishment of an extensive root system before this becomes strained under the demands of a maturing fruit crop. Even though economic conditions dictate the need for early production, tree vigor and the need to sustain long-term production capacity necessitate the establishment of a healthy and extensive root system prior to the onset of production. This article reviews the pertinent literature concerning the long-term persistence of soil profile modifications and discusses practical methods which may improve root vigor of fruit trees in hardpan soils. A variety of experiments have been carried out in past years to evaluate the effects of soil profile modification on drainage, water availability, frost heaving and crop yield. In general, the deeper and more extensive the initial soil disturbance is, the better the results (Unger 1979). Various experiments (Mech et al. 1967, Bradford and Blanchar 1977) found that mixing the top soil with sub-surface layers, and additions of lime, fertilizer or even sawdust significantly increased yields of alfalfa and sorghum. It is reasonable to assume that such an improved growth environment also will foster the development of fruit trees, both above and below ground. Recent research reports (Unger, 1979) stress the importance of mixing the topsoil with the subsoil to obtain lasting results. Studies in New York indicated that modification of a hardpan by mechanical disturbance alone, resulted in re-establish ment of dense soil layers in less than 11 years while buried topsoil remained less dense even after that period (Fritton and Olson, 1972). Researchers in Pennsylvania found that additions of organic matter wiU delay the soil's return to its original bulk density for a period of 7 to 8 years (Fritton et al. 1983). That study also reported the ineffectiveness of subsoiling and deep tillage when the topsoil was not mixed with subsoil. The use of topsoil from old orchards for new plantings may be less desirable when the soil is suspected to contain large numbers of nematodes. Thorough mechanical mixing may reduce the nematode population susbstantially (R. Rohde, personal communication). Use of non-orchard topsoil, hay or peat will prevent a nematode problem and give the young trees a head start, although this method probably is more costly. -15- A comparison of various apple planting methods in West Virginia (Auxt et al., 1980) showed that tree vigor was best when procedures were used which resulted in a large disturbance of the soil. Trees planted by backhoe or tree planter were most successfully established, while a conventional 24" soil auger resulted in less tree vigor and anchorage. It was found that use of 12" or 24" augers resulted in significant soil compaction, which negatively affected tree growth. The West Virginia soils contained more clay than most Massachusetts orchard soils, but smearing of the soil can be a significant problem in this region as most of the trees are planted during early spring when the soil often is extremely wet. While the long-term effects of soil profile modification are debatable, the short-term benefits are beyond doubt. These include improved drainage, aeration and water holding capacity, and less problems with frost heaving. When planting fruit trees it is generally a good practice to make the planting hole as large as possible. When the soil contains a hardpan at shallow depth this procedure is even more important to provide the tree with an environment for optimum growth. Mixing topsoil with the subsoil, and additions of lime, fertilizer and organic matter such as hay and peat, will prolong the effect of soil profile modification and thus lengthen the period of root prolification. Smearing of the soil should be prevented, but is especially important when augers are used. When smearing in the borehole is evident, remove the smeared surface with a knife. Never plant the trees in waterlogged planting holes. Wait until the soils dry out or plant the trees in the fall. If excessive wetness is a reoccuring problem at the future planting site, ensure proper drainage first and select rootstocks which can endure wet feet. Anybody can plant a tree. Planting of a tree which will last and prosper takes considerable time and care. References Cited 1. Auxt, T., S. Blizzard, and K. Elliott. 1980. Comparison of apple planting methods. J. Am. Soc. Hort. 105:468-472. 2. Bradford, J.M. and R.W. Blanchar. 1977. Profile modification of a Fragiudalf to increase crop production. Soil Sci. Soc. Am. J. 4:127-121. 3. Fritton, D.D., and G.W. Olson. 1972. Bulk density of a fragipan soil in natural and disturbed profiles. Soil Sci. Soc. Am. Proc. 36:686-689. 4. Fritton, D.D., F.N. Swader, and K. Hoddinott. 1983. Profile modification persistence in a fragipan soil. Soil Sci. 136:124-130. 5. Mech, S.J., G.M. Horner , L.M. Cox, and E.E. Cary. 1967. Soil profile modification by backhoe mixing and deep plowing. Trans. Am. Soc. Agri. Eng. 10:775-779. -16- THE APPLE MAGGOT IN MASSACHUSETTS, MICHIGAN AND WEST COAST STATES Ronald J. Prokopy Department of Entomology Massachusetts apple growers are all too familiar with the apple maggot and the type of fruit injury that this pest can cause. During our pilot integrated pest management (IPM) program on apples in Massachusetts from 1978-1982, we used sticky-coated red wooden spheres to monitor the time and extent of maggot activity in 16-60 commercial orchard blocks each year. Without exception, at least a few maggot flies were captured annually in each block. In some cases, several hundred were caught in a single block. Our experience shows that 99.9% or more orchard maggot fly populations in Massachusetts originate from wild or abandoned host apple or hawthorn trees within a few hundred yards of the orchard. On only 2 occasions have we found maggot flies emerging from within a commercial orchard itself. In both of these, maggot-infested early-maturing varieties such as Puritan and Astrachan were not harvested the previous year. Despite the continuous pressure that maggot flies exert on our Massachusetts orchards, only 0.08 and 0.09% of harvested fruit showed maggot injury in IPM and check orchards, respectively, during the 5 years of the pilot IPM program [see FRUIT NOTES 48(3)]. The principal reason for this comparatively low fruit injury is the high sensitivity of the adults to even low dosages of pesticide. Moreover, as shown by the work of Dr. Harvey Reissig of Geneva, New York, some pesticides such as Guthion are highly effective not only against the adults but also kill the eggs and young larvae, just beneath the fruit skin. Our experience reveals that so long as growers rely on red sphere trap captures to determine need and timing of maggot fly sprays, there is very little chance of any injury occurring. Most of the maggot injury detected in Massachusetts has been on late varieties such as Delicious and Golden Delicious in cases where substantial fly immigration occurred 2 or more weeks after spraying ceased for the year. Michigan apple growers in 1983 experienced more apple maggot injury than at any time during the past 2-3 decades. According to Michigan fruit entomologist Dr. Gus Howitt, fruit of late varieties such as Jonathan had more than 5% maggot injury in many orchards. Dr. Howitt told me that hundreds of thousands of bushels have been rejected for fresh fruit market and for processing because of excessive maggot injury. Dr. Howitt attributed the severe maggot problem in Michigan in 1983 to the very dry summer, which precluded summer emergence of flies from overwintering pupae. Emergence didn't begin in full force until just after heavy rains in late August and early September. By that time, most of the summer-maturing fruits on wild or abandoned trees had fallen, thereby stimulating extensive immigration of flies into commercial orchards. The warm September was favorable for fly egglaying in late varieties. Also, -17- red spheres were used by only a handful of Michigan growers to monitor fly activity, and most spraying had ceased by early to mid-August. This combination of events undoubtedly explains the maggot fly problem which occurred in Michigan. It should serve as a reminder to us that the comparatively little effort required to emplace and examine red spheres for monitoring maggot fly abundance can pay very large dividends. Eastern and midwestern growers are not the only ones who must be concerned with apple maggot. In 1979, a homeowner near Portland, Oregon brought some rotting apples to the local extension service which were diagnosed as being heavily infested with apple maggot larvae. Subsequent trapping and fruit injury surveys on the west coast showed that apple maggot is more or less continuously distributed from southern Washington to northern California. Numerous wild apple and hawthorn host trees in presently infested areas appear capable of supporting substantial fly populations. Just how far the fly can penetrate into the major apple growing regions around Yakima and Wenatchee in Washington is uncertain. The very dry summers in the Washington state fruit growing areas coupled with the relatively low numbers of wild host trees, are factors arguing against the widespread establishment of apple maggot much beyond the northern border of Oregon. Nonetheless, a concerted and expensive effort is now underway to maintain a buffer (fly-free) zone around the present infestation area in Washington to prevent any further northward movement. The buffer zone, about 15 miles wide, is trapped heavily (50-80 traps per square mile) for maggot flies. Imidan is sprayed extensively in locales surrounding sites of trap captures. In addition, there is an intensive host tree removal program within the buffer zone. In Oregon, the apple maggot is now so entrenched (it may have been there, undetected, for 10-20 years prior to 1979) that no feasible means exists of exluding it from the vicinity of any of the apple growing areas. However, buffer zones, similar to those in Washington, have been erected immediately around certain locales of intensive apple growing, such as the Hood River Valley. Possibly California apple growers believed the fly would never be so bold as to move south across the Oregon border. But on August 24, 1983 the first flies were detected in traps about 50 miles into California. Within 2 months, the area of known infestation reached about 150 miles south into California. Actually, it shouldn't be surprising that the apple maggot was found in California. During the past 30 years apple maggot (in the form of larvae in infested fruit) was intercepted by Border Station Inspectors more often than any other insect pest entering that state. In mid-October, 1983 1 was asked to chair a panel of scientists to go before officials of the California Department of Agriculture, growers, and the public to make recommendations as to what to do about this "sudden" invasion of the fly. Because of the near hysteria caused by the Mediterranean fruit fly invasion of California in 1981, 1 was very reluctant to accept this charge. But it proved to be a highly informative and relatively calm experience. Our panel concluded that the apple maggot fly had probably been in California for at least 5 years. Scouts were finding it nearly everywhere they looked, although -18- never in very large numbers at any one site. Possibly the apple maggot will have difficulty building into high populations in more southern regions such as California. At present, its southernmost distribution lies only a hundred miles or so north of one of the major California apple producing areas. For several biologically-based reasons, our panel concluded that it was virtually impossible to eradicate the apple maggot from California, given its already widespread distribution in that state and neighboring Oregon and given the fact that a major part of the present area of infestation lies in the heart of the California marijuana growing region. Marijuana is the largest "agricultural" crop of California, even exceeding cotton, and is worth more than 1.3 billion dollars per year. It is very dangerous for state employees to explore terrain within this region (often laden with land mines to deter unwanted visitors) to seek out maggot flies and host trees to eradicate. Hence we recommended adoption of buffer zone procedures similar to those used in Washington and Oregon. Whether this recommendation will in fact be adopted remains to be seen. Thus, 1983 was a big year for the apple maggot in Michigan, Washington, Oregon, and California. We are fortunate that 1983 was not a problem year for apple maggot in Massachusetts. Gala - An Apple Variety Worthy of Trial James F. Anderson Department of Plant and Soil Sciences Gala, a variety from New Zealand has been receiving much favorable attention. This variety resulted from a cross between Kidd's Orange and Golden Delicious and was introduced in 1960. We have fruited Gala for 4 seasons. The fruit has been medium to large in size on these trees planted in 1978. The fruits are generally round-conic in shape. The skin is smooth and the color golden-yellow overlaid with about 80% red. The flesh is yellow crisp and has a very good flavor. The fruit in our Belchertown orchard has been harvested during the second and third week of September, the fruit hangs well on the tree. The fruit stores well for a fall apple. Gala appears to be a productive variety and merits trial by those growers operating farm markets. -19- THE USE OF PROMALIN TO IMPROVE THE SHAPE OF DELICIOUS APPLES Duane W. Greene and William J. Lord Department of Plant and Soil Sciences Promalin is a plant growth regulator that has been used for several years in Massachusetts orchards to increase the length (L/D ratios or typiness) of Delicious apples (Figure 1). Promalin contains equal amounts of gibberellins (GA4 and GA7) and a cytokinin, 6-benzyladenine. We previously reviewed research results and made suggestions for the use of Promalin (FRUIT NOTES 43(3):4-7, 44(3):4-8 and 45(3):8-12). The purposes of this article are to summarize results from several years of research results with Promalin, and to make suggestions for successful use of Promalin to enhance the shape of Delicious. Figure 1. The effect of Promalin on shape of Delicious apples. The apple on the left was treated with I2 pt Promalin per acre and the one on the right was unsprayed. Coverage. When using plant growth regulators it is generally emphasized that uniform spray coverage is essential for satisfactory results. This is especially true when using Promalin. In both 1978 and 1979 the greatest increase in L/D ratio occurred only when Promalin came in direct contact with the portion of the flower that develops into the fruit (receptacle and calyx end of the receptacle). Application to the pedicel (stem) was much less effective (Table 1). -20- Table 1. Effect of the site of Promalin application on the L/D ratio of Richared Delicious apples. Treatment^ L/D Ratio* (Microliters) 1978 1979 Check 0.93cX 0.91c Petals, 25y 0.94c 0.91c Petals, 150 0.99b Receptacle surface. 25 1.03a 1.03a In Calyx end, , 25 1.03a 1.04a Pedicel, 25 0.97b Spur leaves. 250 0.90c ^50 ppm solution containing 0.05% X-77 applied at fullbloom. All blossom clusters reduced to one flower and then hand-pollinated with Early Mcintosh pollen. YA 25 microliter droplet was large enough to wet the receptacle or pedicel surface with no runoff. '^Numbers in a column followed by a different letter are significantly different at odds of 19 to 1. Petals at the normal application time account for a substantial portion of the flower surface area. However, they appear to be relatively unimportant as a vehicle for absorption. Even 150 pi applied to the petals (the volume comparable to a dilute application) was only moderately effective at increasing the L/D ratios. Spur leaves were totally ineffective as sites of Promalin absorption. Therefore, not only must Promalin be directed uniformly to all parts of the tree but droplets must also come in direct contact with the receptacle of each flower for the maximum response. Use of surfactants and adjusting pH of spray solution. Surfactants frequently increase the penetration of growth regulators. However, the use of surfactants is generally not recommended with growth regulators, since most formulated growth regulators (e.g.. Alar 85, Fruitone N, e.tc.) already contain a surfactant. In contrast, the Promalin formulation contains no surfactant, so we thought that the use of a surfactant with Promalin might increase the Promalin effect on fruit L/D ratio. In addition, the ability of gibberellins to enter the plant may be regulated by spray pH. Reduction of the pH of the spray from near neutrality (pH 7.0) down to near pH 4.0 should enhance penetration, but field effects have not been well documented. A trial was conducted using a combination of surfactants and a reduction in spray pH was done on Royal Red Delicious. Glyodin, Biofilm and Buffer-X served as surfactants and the pH was reduced in 2 treatments with the nutrient spray Sorba Mg. Buffer-X contains a buffer to reduce pH (pH 4.8 in this trial). The combined sprays of a surfactant with the commercial buffer tended to increase the L/D ratio beyond that produced by Promalin alone (Table 2). Growers must be cautioned, however, that the enhanced response with surfactants and/or buffers also increase the chance of thinning. L/D = Length/diameter ratio. An apple with an L/D ratio of 1.04 is longer and more "typey" than one with a ratio of 0.90. -21- Table 2. The effects of surfactants and pH modification on the performance of Promalin applied to Royal Red Delicious, 1978. Treatment^ Fruit Fruit per cm weight limb circ. L/D ratio fe) Check 7. lay 0.95c 154abc Promalin G.Oab 1.00b 142b Promalin + Sorba (Mg)+ Glyodin 4.9bc 1.04a 146bc Promalin + Sorba (Mg)+ Biofilm 4.8bc 1.03a 156ab Promalin + Buffer-X 4.1c 1.02ab 161a ^l pt of each chemical was used per 100 gal. of water. Treatments applied at rate of 125 gal/acre at petal fall of the king blossom. yNumbers in a column followed by different letters are significantly different at odds of 19 to 1. Fruit set following Promalin application. Within 2-3 days following a Promalin appli- cation, calyx swelling and closing is apparent, first on the king blossom and then on lateral blossoms. Promalin merely accelerates that which normally occurs on pollinated flowers. Ten to 12 days after application, Promalin appears to have increased fruit set. However, about 15 days after bloom, yellowing of the pedicels occurs on many of the developing fruit in the cluster. By 3 weeks after bloom most of the less vigorous fruit have dropped and within 4 weeks after bloom fruit set has been determined and subsequent drop is minimal. Thinning due to Promalin application. It is well documented that Promalin can thin. However, in most cases where Promalin has thinned, label directions were not followed. Causes of thinning include: 1. Overapplication. The most frequent cause of thinning due to over-application is poor sprayer calibration. Portions of a tree also may be overthinned due to poor spray distribution within the tree. Lower, weaker spurs thin more easily than more vigorous spurs located in the tops of trees. 2. Application during hot weather. If Promalin is applied when temperatures exceed 85°F, the likelihood of thinning is dramatically increased. 3. Application on young trees. Treatment of young trees frequently results in complete removal of the crop. This is particularly detrimental on young Delicious trees just coming into bearing since even a small crop is quite useful to bring down branches, help slow growth and encourage consistent fruiting. Nevertheless, thinning due to Promalin may also be more apparent than real. Pro- malin may merely accelerate young fruit abscission that would normally occur during the early 'June-drop' period. It would certainly appear that Promalin was increasing thinning if you assessed fruit set 2-3 weeks after bloom. However, in most situations, it appears that Promalin has advanced the 'June-drop' by about 2-3 weeks, thus giving only the impression of thinning. While Promalin can indeed cause thinning, caution should be exercised in concluding that this has happened on your trees. -22- Use of chemical thinning following Promalin application. Promalin applied by itself is capable of thinning. A chemical thinner, generally Sevin, is often used during the post-bloom period on Delicious. Frequently, increased thinning is observed when 2 different thinning agents are applied. Therefore, it is particularly important to know if Promalin-treated trees are thinned to a greater extent than unsprayed trees when chemical thinners are applied. We have attempted to answer this question with 5 different experiments over the past 4 years using both Sevin and NAA as chemical thinners. Results of a typical experiment are shown in Table 3. When applied as a dilute spray during the bloom period, Promalin thinned. Sevin thinned Promalin-treated or untreated trees comparably. In no experiment did the combination of Promalin with either chemical thinner reduce the crop load below that on trees treated with either Promalin or the chemical thinner alone. Very 'typey' fruit with large L/D ratios were harvested from both Promalin and Promalin-plus-chemical thinner trees. Table 3. Effect of Promalin, Sevin, and naphthaleneticetic acid (NAA) on fruit set, fruit characteristics anc yield of Double Red Delicious apples. 1982. Blossom clusters/ cm limb circum. 1982 Fruit Fruit wt. (g) L/D ratio Seeds/ fruit Treatment^ (ppm) per cm limb circum. per 100 blossom clusters Yield (bu/tree) Check 10.1a 7.6ab 75.7b 169a 0.96b 6.3a 11.0a Promalin 25 10.1a 5.1c 56.3bc 179a 1.04a 5.6b 8.9b Promalin 25 + Sevin 1200 9.9a A.lc /i0.3c 176a l.OAa 4.5c 6.1c Promalin 25 + NAA 6 9.6a 6.3bc 66.9b 123b 1.03a 1.7d 7.2bc Sevin 1200 9.0a ii.lC 55.0bc 176a 0.96b 4.0c 6.5c NAA 6 9.6a 9.1a 100.7a 122b 0.93c 1.9d 6.8bc ^Promalin applied 5/12/82 (full bloom 5/13/82) as a dilute spray with 1 pt/100 gal. Glyodin. Sevin and NAA applied as a dilute spray on 5/30/82. Weather conditions following chemical thinner application were cloudy and moist thus favoring foliar penetration. Complete drying of spray droplets did not occur for 24 hours. Trees treated with NAA soon showed typical leaf epinasty (twisting) and the development and retention of many small and seedless 'pygmy' fruit became apparent. It is for this reason that NAA appears not to have thinned and that average fruit size on these trees was considerably smaller (Table 3). Although 'pygmy' fruit were observed only one year, this illustrates the potential danger of using NAA as a chemical thinner for Delicious. It should be noted that Promalin did not increase fruit weight (Table 3). We have never observed an increase in fruit size following Promalin application unless the treatment caused significant thinning. The increase in fruit length caused by Promalin was accompanied by a corresponding reduction in fruit diameter. The reduced fruit diameter is attributed to a reduction in seed number. -23- Uniformity of Promalin response on the tree. The L/D ratio of fruits will vary considerably on a tree. This is due to the location of the fruit on the tree and their origin within the blossom cluster. The L/D ratio distribution of fruits from untreated and Promalin-treated trees is similar (Figure 2). This indicates that a Promalin application increases the L/D ratio of all fruits on the tree equally. Therefore, a grower can expect to find some rather flat-looking Delicious on Promalin-treated trees at harvest time although there should be fewer than on check trees. I .20 Figure 2. The L/D ratio distribution of fruits from trees receiving a 25 ppm dilute spray of Promalin and from Control trees. Variable Promalin response. It has been observed that the L/D ratio following Promalin application is sometimes less than expected. We believe that there are at least two reasons for this. Weather, and especially high temperature during and following the bloom period, can influence fruit shape. Undoubtedly, part of the diminished response can be attributed to high temperature during and following Promalin application. It is known that temperature during and following bloom can have a direct effect on cell division and expansion in the calyx end of fruit. Based upon several experiments over several years where Promalin was placed directly in the calyx of fruit it is concluded that Promalin always elongates fruit. Promalin promotes at least 2 independent processes: fruit elongation and fruit thinning. In situations where a diminished response is observed, Promalin may be thinning from the cluster the fruit that have been elongated. -24- Effect of Promalin on pollinizers. Delicious is not the only cultivar that can be elongated with Promalin. If pollinizers are located within the rows of Delicious being sprayed you can expect elongation of these fruit also. Increased length of such cultivars as Mcintosh and Cortland in most cases would not be desirable. Therefore, when applying Promalin attempts should be made to avoid spraying pollinizer trees where increased calyx-end length is not wanted. Suggestions for Promalin use 1. Calibrate your sprayer. Thinning due to Promalin has often been traced to overapplication because of improper sprayer calibration and nozzle adjustment. The margin of error with Promalin is not great. The label suggests that Promalin should be applied in 100-200 gal/acre. Therefore, an error in application of only 50 gal/acre can result in a 50% increase in the amount of Promalin applied. 2. Do not apply more than \i pts/acre of Promalin. 3. Do not apply Promalin when the temperature exceeds 85° F. Excessively warm temperatures may increase the thinning response without a corresponding increase in the shape response. 4. Do not apply Promalin on young trees. A good rule-of-thumb is not to apply this growth regulator on any tree until it is bearing heavily enough to consider chemical thinning. 5. Apply Promalin as soon after opening of the king blossom as weather permits. This is earlier than we have suggested in the past. It is our feeling that the reduced leaf surface at this earlier timing may reduce the possibility of thinning. 6. The addition of surfactants or spreader stickers increases both the fruit shape and thinning response to Promalin. On trees where bloom is heavy and the use of a chemical thinner is anticipated, the addition of a surfactant or spreader sticker is suggested. 7. Promalin may thin as well as accelerate the normal fruit abscission process. Therefore, before using a chemical thinner on Promalin-treated trees, check initial set to see if additional thinning would be desirable. It is possible that no chemical thinner is needed on Promalin treated trees. If a thinner is used on Promalin-treated trees it is unlikely that thinning will be excessive. 8. Leave a few untreated and representative trees in the Promalin-treated block. Initial fruit set, subsquent drop and fruit shape are never constant from year to year. Therefore, the only way to accurately assess the performance of Promalin in your orchard is to leave a few untreated trees in the same block to indicate what would have happened in the absence of the Promalin spray. -25- FREEDOM: A NEW DISEASE-RESISTANT APPLE William J. Manning and Daniel R. Cooley Department of Plant Pathology The New York State Agricultural Experiment Station at Geneva has released a new disease-resistant apple named Freedom. The new cultivar is described by Professor Robert C. Lamb, Freedom's originator, as a "very productive, large attractive apple of good quality that can be used either for the fresh market or for processing." Like Liberty, Freedom (formerly NY58553-1) is immune to apple scab and moderately resistant to powdery mildew, but slightly less resistant to cedar apple rust and fire blight than Liberty. Freedom blooms at midseason in Geneva and has been shown to be a good pollen source for other cultivars. Fruit ripen with Delicious, around October 5 at Geneva. They are described as being large (3g in.), oblate, with 80% bright red stripes over yellow background. The fruit are medium fine, firm, tender and juicy, subacid, with cream-colored flesh. Freedom will hold in normal refrigerated storage until January. Freedom will be available (patent is pending) through licensed nurseries or from the New York State Fruit Testing Cooperative, Geneva, N.Y. 14456. We plan to add it to our disease-resistant test block at Belchertown. ********** PERFORMANCE OF DISEASE-RESISTANT APPLES William J. Manning and Daniel R. Cooley Department of Plant Pathology In 1978, we planted a block of disease-resistant apples at the Horticultural Research Center at Belchertown. Fungicides have never been used in this block and only a minimal insecticide program has been followed. Fruit were harvested for the first time in 1982 and observations made and cultivar descriptions were published in FRUIT NOTES (Vol. 48 No. 1, Winter, 1983, pp. 6-8). Performance evaluations of the disease-resistant cultivars were continued in 1983. Disease pressure was high in the spring due to long periods of cool wet weather and near drought conditions and high temperatures were experienced during the summer. During the second week in August, leaves were examined for symptoms of black rot (frog-eye leaf spot) (Physalospora obtusa), cedar apple rust (Gymnosporangium juniperi-Virginianae), and scab (Venturia inaequalia). Twenty five leaves, on randomly- selected terminals, were evaluated on each of 3 trees. Leaves were counted as having significant symptoms if 2 or more spots of black rot, cedar apple rust or scab were observed per leaf. Results were expressed as % of leaves with symptoms per 75 leaves examined (Table 1). -26- Table 1. Evaluation of disease-resistant apples in Massachusetts, 1983. Leaf symtpoms^ Cultivar Black rot Imperial Mcintosh 13 Liberty 21 Macfree 46 Nova Easy-gro 24 NY613452 35 Priscilla 10 Sir Prize 10 Cedar apple rust Scab 0 0 0 0 4 0 48** 100*** 0 0 0 0 0 0 % of 75 leaves on 3 trees with 2 or more spots/leaf- 5 or more spots/leaf. **Both leaves and fruit. All of the leaves and fruit of Imperial Mcintosh had significant scab lesions, while all others were completely free from scab (Table 1). Sir Prize is very rust susceptible, and respond accordingly. A few small, non-functional rust lesions were noted on NY613452. Foliar black rot symptoms were more extensive than in 1982. An occasional apple with black rot was observed for Macfree, NY613452, and Liberty (Table 1). This may be a potential future concern if black rot innoculum continues to increase. For comparison. Table 2 shows the disease-resistance ratings and commonly grown apple cultivars from a test in New York State (Cornell University) published in 1983. Table 2. List of disease resistance of some apple varieties from New York test, 1983. Cultivar Resistance rating Apple scab Cedar apple rust fire blight Powdery mildew Cortland 4 Delicious 3 Empire 4 Freedom 1 Golden Delicious 3 Idared 3 Jerseymac 4 Liberty I Macfree I Macoun 4 Mcintosh 4 Mutsu 4 Northern Spy 3 Nova Easygro 1 Paulared 3 Prima 1 Priscilla 1 Sir Prize 1 Spartan 3 3 1 2 2 4 3 1 1 3 2 1 3 3 1 2 4 1 3 3 2 2 3 3 4 3 2 2 3 3 4 2 2 3 2 2 4 4 2 3 2 3 3 3 3 4 3 3 3 2 3 2 2 1 = very resistant. No control needed. 2 = resistant. Control needed only under high disease pressure. 3 = susceptible. Control usually needed where disease is prevalent. 4 = very susceptible. Control always needed where disease is present. Acknowledgements: We thank Tony Rossi and others at the Horticultural Research Center for maintaining the block and applying insecticides. This activity is supported by the Massachusetts Cooperative Extension Service. -27- GRAY MOLD ON STRAWBERRIES Daniel R. Cooley and William J. Manning Department of Plant Pathology One of the most aggravating and economically damaging strawberry diseases is gray mold. It strikes after primary investments in plants have been made, and presents an ever-present, difficult to manage, disease problem. A conservative estimate gauges yield lost from fruit rots in general at about 10%. In the Northeast, the majority of this loss is caused by Botrytis cinerea, the gray mold fungus. Gray mold is a particular problem because, unlike most other berry rots, it often attacks living plants in the field as well as the harvested fruit. The pathogen is well-adapted for survival. Botrytis occurs on a wide-range of hosts, and while an isolate from a different host may not be as virulent as a strawberry isolate, in most cases B. cinerea isolates can cause some degree of gray mold. Botrytis also has the ability to colonize dead or living tissue. The fungus will often establish itself on dead or aging plant tissue and move from that tissue to healthy areas. Petals and other parts of older flowers are likely to be colonized first. These infections may destroy the developing fruit immediately, or may remain latent until the fruit is well-ripened or harvested. As the fruit ripens, it becomes easier for the fungus to attack it, because endogenous enzymes in the fruit break down mechanical barriers to fungal infection. Substrates for fungal growth become more available, and biochemical defenses decrease as the fruit ripens, making a ripe strawberry an excellent habitat for Botrytis and other rotting fungi. Botrytis cinerea inoculum is very common. In strawberry plantings in the Northeast, Botrytis usually overwinters in dead leaves and other decaying plant tissue, using survival structures called sclerotia. In spring, as the temperature warms, the sclerotia germinate and produce spores. These spores are carried about strawberry plantings by air currents, splashing moisture or insects. In the presence of free water on the plant, the spores germinate. Though the fungus is active over a wide range of temperatures, optimum conditions for a Botrytis epidemic occur when temperatures are approximately 60 to 70° F, and relative humidity exceeds 90%. If temperatures and humidity are optimal, an epidemic can occur in as little as 28 hours. One of the driving forces behind this rapid disease development is the prolific reproductive capacity of the fungus. Gray mold is an example of what is called a 'compound interest disease'. That is, each reproductive unit, in this case a condium or spore, can produce hundreds of new spores, which can each produce hundreds more spores, and so on as long as environmental conditions are favorable. Each generation progresses rapidly in warm, humid weather. With conidia multiplying at a high 'interest' rate, disease pressure becomes severe. Add to this the fact that initial inoculum is virtually always present, and gray mold becomes extremely difficult to manage. Figure 1 shows a diagram of the disease cycle for gray mold. Most management efforts aimed at gray mold rely heavily on fungicides. To be effective, fungicides must be applied at proper times. Most effective programs attempt to prevent initial infections in the spring, and concentrate on protecting the plant, particularly the flowers and fruit, from infections when environmental conditions favor the disease. To be effective, a layer of fungicide must be kept on the plant -28- surface. A minimum spray schedule involves 3 applications, one at 10% bloom, one at 50% bloom and one at tiie end of bloom. Where gray mold has historically been a problem, applications should start at white bud, then the 3 bloom applications should be made, and then applications should be made during fruit development at 5 to 10 day intervals. To maximize the protection it is wise to time spraying according to plant development and weather. Rapid plant growth leaves tissue unprotected until the next application, and heavy rain for more than 24 hours washes fungicides off and provides an excellent infection environment. Therefore, in addition to the prescribed applications, additional sprays should be made after 24 hours if rainy periods occur. Such intensive fungicide spraying can and has led to resistance to some chemicals. Specifically, the systemmic fungicides, benomyl (Benlate®), thiophanate-methyl (Topsin M®) and vinclozolin (Ronilan®) can become ineffective if used alone or too heavily. The broad-spectrum contact fungicides, captan and thiram, are not likely to produce the same problems. As a consequence Benlate®, Topsin-M® or Ronilan® should be used in combination with a half-rate of captan. This reduces the risk of resistant Botrytis developing, while enabling growers to use one of three very effective chemicals. The rates for these chemicals are given in 'Managing Diseases and Insects on Small Fruits in New England', available from the Massachusetts Extension Service, Cottage A, University of Massachusetts, Amherst 01003. There is another problem with the systemic fungicides in that they do not control Rhizoctonia, Phytophthora, Rhizopus and Mucor, fungi which also cause berry rots. In some cases, post-harvest rots caused by Rhizopus and Phytophthora have actually increased where Benlate or Ronilan were the only fungicides used. Cultural practices can reduce the amount of inoculum which contacts plants, and reduce the free moisture on plants necessary for infection. Mulching with straw or plastic keeps berries from contacting soil, hence reducing inoculum pressure and improves fungicide coverage. Narrower rows promote air circulation and drying, minimal weeds accomplishes similar goals. There is some evidence that adding micronutrients may decrease gray mold, though the interaction of nutrition and the disease has not received much study. Some cultivars are more resistant to gray mold than others. In general, berries which are firmer are more resistant. A recent study at Cornell rated the following cultivars in decreasing order of susceptibility to berry rots: Honeoye, Guardian, Canoga, Tenira, Surecrop, Holiday, Veestar, Vibrant and Earlidawn. Of these, the first three cultivars were significantly more resistant than the others. Plant breeders are continuing to develop gray mold resistant cultivars. Finally, an experimental approach to control has been tried using the biological control fungus Trichoderma. Preliminary results were not as consistent as control achieved by fungicides, but Trichoderma may yet be developed into an effective alternative to fungicide control. In the future, it may be possible to reduce or eliminate fungicides by using a combination of resistant cultivars, biological control agents and careful management of horticultural practices. Obviously, these measures are aimed at reducing field incidence of gray mold. These practices will, as a consequence, reduce post-harvest disease incidence. Refrigeration is an option most small growers use to further reduce post-harvest gray mold. Beyond one or two days after harvest, strawberries become increasingly susceptible to rot, and the best strategy is to use or process them as soon as possible after harvest. Acknowledgment: Special thanks to Paula Saucier for the illustration. -29- spore mass /< In so'ing moisture encourages sderolia to grow and produce spores Fungus overwinters in plant debris, such as dead leaves When plants are wet. spores rapidly intecl unprotected llorai parts Infections cause browning and death in some tlowers, or remain latent in developing Iruit i^ Alter harvest the potential lor rot increases greatly, limiting storage to one to lour days As llowers age and Iruit ripens, their susceptibility to gray moid increases Older inlections are gray and luzzy GRAY MOLD ON STRAWBERRY, BOTRYTIS CINEREA Department of Plant and Soil Sciences Non-Profit Org. French Hall U.S. POSTAGE University of Massachusetts PAID Annherst, MA 01003 Permit No. 2 3-20028 Amherst, MA 01002 : 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 49 No. 3 SUMMER ISSUE, 1984 Table of Contents Factors Influencing DPA Residues on Apples Pomological Notes — Response to Chemical Thinning Harvesting, Storing and Ripening Pears Apple Fruit Growth The "Marshall" Mcintosh Pomological Paragraph Pomological Notes Predicting Harvest Size of Mcintosh Apples A Survey of the Cost of Growing and Harvesting Apples in Eastern New York in 1983. Daily Activity of Apple Blotch Leafminer Adults ssued by the Cooperative Extension Service, E. Bruce MacDougall, Dean, in further- ince of the Acts of May 8 and June 30, 1914; United States Department of Agriculture ind County Extension Services cooperating. The Cooperative Extension Service offers squal opportunity in programs and employment. FACTORS INFLUENCING DPA RESIDUES ON APPLES William J. Bramlage Department of Plant and Soil Sciences Most apple growers in New England use diphenylamine (DPA) as a postharvest dip or drench to control scald on apples. Although these treatments have been generally effective in controlling scald, results of a given treatment are not always the same. One reason for this is that fruit vary considerably in their susceptibility to scald, depending on variety, fruit maturity, fruit nutrition, and growing conditions especially the temperature that occurred during the days shortly before harvest. Another reason for variable results is that a number of factors affect the amount of residue left on fruit by a treatment. (It is this residue that protects the fruit from scald during and following storage.) A recent study by Drs. Shih-Lo Lee, Asela Carag, and Hesh Kaplan of Decco Tiltbelt Division, Pennwalt Corporation, Monrovia, California (1) demonstrated some important factors influencing this residue. Most of their studies were with Granny Smith apples, which are very sensitive to scald, and most employed No Scald DPA EC-283®, 31% a.i., as the test material. Their results can be summarized as follows: 1. Effect of DPA solution temperature. Cold apples were dipped in solutions at 41°, 55°, 70° and 95° F for 30 seconds, 1 minute, or 2 minutes. When dipped for 30 seconds, solution temperature had no effect on DPA residue, but when dipping time was 1 minute a solution temperature of 95° F. doubled the residue left by solutions at the lower temperatures. It should be noted that solutions of 41°, 55°, and 70° F. all left approximately the same residue regardless of solution temperature or treatment time. 2. Effect of fruit temperature. Cold apples were kept at 40°, 55°, or 72° F. for 10 to 12 hours to warm before dipping in a 70° F. solution for 1 minute. The coldest apples (40° F) retained the least residue, but there was no difference between those at 55° and 72° F. 3. Effect of dipping time. Apples were dipped for periods varying from 15 seconds to 4 minutes. A dip of only 15 seconds produced less residue than the other dipping periods, but all periods of 30 seconds or more produced the same residue. 4. Effect of DPA concentration. When apples were dipped in concentrations of DPA varying from 500 to 2500 ppm, the amount of residue increased with concentration. There was twice as much residue from 2500 ppm as from 500 ppm, but perhaps of greater interest is the finding that there was about one-third more residue from 2000 ppm than from 1000 ppm, since our recommendation usually calls for use of "1000 to 2000 ppm". ® Trade name -2- 5. Effect of additives. Addition of calcium chloride at 24 lbs. per 100 gallons did not affect DPA residue, and neither did the addition of a surfactant. 6. Differences among varieties. The authors compared Granny Smith apples with Golden Delicious, Delicious, Jonathan, and Rome Beauty. When the fruit were all dipped under identical conditions, the residues were similar on all varieties except Delicious, which retained almost twice as much residue as did the other varieties. 7. Effect of DPA formulation. Three different commercial formulations of DPA were tested under identical conditions, and one of the formulations left twice as much residue as did the other 2 formulations. Conclusions These results indicate that apples should be treated for at least 30 seconds, but that prolonged periods provide no additional benefit unless the dipping solution is hot. They also show that cold apples will retain less residue than warm ones. However, the temperature of the dip solution is of little consequence unless a quite warm solution is used, which will greatly increase the amount of residue. They also illustrate that the same treatment can protect different varieties to different extents, and that different DPA formulations can produce different results. Within the solution itself, DPA concentration was highly important, but addition of CaCl2 or surfactant had no effect on DPA residue. Addition of fungicides to the solution was not tested. The results of this study should be of considerable interest to apple growers, who are frequently concerned about how treatment conditions affect scald control. Literature Cited 1. Lee, S-L, A. Carag, and H.J. Kaplan. 1984. Factors influencing the uptake of diphenylamine by apples. HortScience 19(l):94-95 POMOLOGICAL NOTES William J. Lord Department of Plant and Soil Sciences Response to chemical thinning. The primary effect of chemical thinning is a reduction in the number of smaller apples rather than a large increase in the size of the remaining fruits. Thinning does not change a potentially small apple into a large fruit but helps to insure that a potentially large apple will size properly. -3- HARVESTING, STORING AND RIPENING PEARS William J. Bramlage Department of Plant and Soil Sciences Pears are not a major crop in New England, yet many growers have modest plantings of them. Most of the crop is marit:4:4::f::t= POMOLOGICAL NOTES William J. Lord Department of Plant and Soil Sciences Plastic bags filled with dirt aid in tree training. According to the Great Lakes Fruit Growers News (April, 1983) Paul Friday of Coloma, Michigan is using small plastic bags with 2 to H lbs. of dirt as tree training aids for young peach, apricot, and tart cherry trees. The dirt-filled plastic bags are fastened with 2 clothespins to the ends of branches requiring spreading. Mr. Friday believes that wide crotch angles on peach trees, as a result of limb positioning, has reduced the number of canker-infested crotches. Producing your own fruit trees. Until recently fruit growers experienced difficulty in obtaining trees from nurseries. Because of this problem, many growers began to propagate their own trees. However, it is now evident that most of us are producing low quality trees which in the long-run will cost us more because of poor performance in the orchard than those purchased from a commercial nursery. Reasons for our lack of success in propagation include poor soil for a nursery, lateness of lining-out the rootstocks, and/or neglect of the nursery. -11- PREDICTING HARVEST SIZE OF McINTOSH APPLES F.W. Southwickl It is known that apple fruit size at harvest from healthy trees can be predicted with reasonable accuracy by measuring fruit size much earlier in the growing season. Therefore, measurements of fruit diameters in July or later can be used to accurately estimate average fruit size of Mcintosh in early- mid- or late-September, assuming severe drought conditions do not develop during July or August. By taking some early size measurements a grower can determine whether or not he should consider doing some hand thinning to improve the overall size of the persisting fruit at harvest. The earlier hand thinning is done after completion of the June drop, the greater the improvement in size of the persisting fruit and the smaller the decrease in total yield. Data in Table 1 can serve as a guide, showing the approximate harvest size of Mcintosh on September 15 when fruit diameters were measured on July 15 and August 1. It is assumed that the Mcintosh were sprayed with Alar-85 in mid-July at a concentration of 1000 ppm for pre-harvest drop control. To determine average fruit size, measure at least 25 fruits a random on several trees in each block. A suitable measuring device for measuring fruit diameters (Cranston Calpher) can be purchased from the McCormack Fruit Tree Co., Inc., 611-A Englewood, Yakima, Washington 98908. Table 1. Prediction of fruit diameter (inches) of Mcintosh apples on September 15, based on size on July 15 or August 1. Fruit diameter Predicted fruit July 15 diameter on September 15 1.4 2.45 1.5 2.55 1.6 2.65 1.7 2.75 1.8 2.85 1.9 3.00 2.0 3.10 Fruit diameter Predicted fruit August 1 diameter on September 15 1.8 2.25 1.9 2.35 2.0 2.55 2.1 2.65 2.2 2.78 2.3 2.95 2.4 3.05 2.5 3.15 Professor Emeritus, Department of Plant and Soil Sciences -12- A SURVEY OF THE COST OF GROWING AND HARVESTING APPLES IN EASTERN NEW YORK IN 1983 William D. Gerling^ Regional Extension Specialist Hudson Valley Lab, Highland, New York This is a survey and analysis of the cost of growing and harvesting apples for eight operations in Eastern New York, It includes operations from throughout the Hudson and Champlain Valley apple producing region. The objective of this study is to assist growers in identifying and analyzing that portion of their total expenditures which can be associated with the growing and harvesting portion of their business. The data contained within the study is thought to be representative of what better-than average growers are doing. Method of Obtaining Data Throughout the 1983 growing season, the growers in the survey were asked to keep a record of where labor was used. In early 1984 the eight operations were mailed survey forms to collect the labor information and other needed information. A short time later, each operation was visited to pick up the forms and collect any additional information that was required. The operations included ranged in size from 41 acres of apples to 585 acres. The fruit produced by these growers account for approximately 8% of the apples produced in Eastern New York. The sample of operations that is included in this study is neither a stratified nor random sample. The purpose of this study is to provide growers with a management tool with which to analyze their business. While the data contained in this report is useful in evaluating a growers operation from a management standpoint, it may not be representative of average costs in Eastern New York for other purposes. Orchards Included in the Survey For this study, acreage of bearing trees include all mature trees, even though they may not have produced a crop or the crop may have have been harvested. It also includes all young trees that produced enough fruit to make harvesting economically feasible, even though the volume of apples might not have been sufficient to cover the cost of growing the fruit. Using this method of determining a bearing acre can have a major impact on a growers average yield, since the number of bushels of apples harvested are divided by the total number of acres considered to be bearing. If a grower has ^Reprinted with the permission of the author. -13- a large acreage of young trees just coming into production, his average yield may be considerably less than a grower who is dealing only with mature trees. This may also increase both his growing and harvesting cost per bushel in the short run. However, if a grower is going to maintain a productive orchard over the long run, it is desirable and even necessary that he constantly plant young trees. If a new planting is expected to have a useful life of from 20-25 years, then approximately 4-5% of the total acreage should be replanted each year. Replanting about the same number of acres each year is desirable from several standpoints: 1. It insures that the productive base of the farm is constantly being renewed. 2. It makes it much easier to provide the labor and equipment needed for the operation as compared to planting larger acreages on an irregular basis. 3. The cash flow needs of business are more constant. It costs from $6,000-$10,000 per acre to plant and care for a young orchard until it begins to pay its own way. When replanting is done on a regular basis this cash flow drain is also more constant and more easily planned for. This year, data was again collected to show the age breakdown of the trees on each operation. This is summarized in Table 1. It illustrates the importance that these growers have placed on establishing new orchards in recent years. However, it also illustrates that orchard replanting has been a very sporadic activity on several of the operations in the study, rather than a regular activity. Many of these operators have now recognized the need to plant approximately the same number of acres of young orchards each year. This year we collected information on the number of acres pruned, average number of sprays per acre, number of acres receiving herbicides, average number of times each grower mowed his orchard and information on irrigation practices. This data is summarized in Table 1 also. Hopefully, it will provide growers with a better understanding of how their cost might compare to the figures contained within this publication. Summer pruning includes all pruning activities done in the bearing orchards during the time from petal fall to harvest, including suckering. The number of sprays per acre include the average of all the sprays to an orchard for insect and disease control, growth regulations, thinning, and foliar fertilizers. The number of bearing acres receiving herbicides include those acres that received some type of herbicide treatment. Some of these may have been treated more than once. All the costs associated with the production of the apple crop on acres of apples considered to be bearing acres are included in Table 2. In some cases, it was easy to identify those expenses associated with the growing phase of the operation, for others it was necessary to estimate what percent of the total expenditure was associated with growing the crop. An example of the latter is the management salary. On none of these operations was one person in charge of only growing the apples. Therefore, it was necessary to estimate what portion of the manager's salary should be charged to the growing phase of the operation. Also, it was necessary to separate the costs of caring for the young non-bearing acres and the costs associated with the bearing acres. -14- The return on investment for orchards, building and equipment recognizes the cost of having capital tied up in the business. If a grower is relying on borrowed capital to finance the ownership of the orchards, buildings and equipment, this cost of capital is an easily identified cost. It is the interest he must pay his lender. However, this cost exists, even if a grower is using his own money. The dollars invested in the business have an earnings potential of their own. These dollars could be invested in the bank or elsewhere and produce some income. This earnings potential must be recognized as an opportunity cost of capital, when a grower invests his money in his own business. His business must earn a profit, over and above the basic earning potential of his capital, to be profitable in a real sense. In this publication the return on investment or opportunity cost of capital is calculated at the rate of 1296 of the value of orchard, buildings and equipment. The value of the orchards, buildings and equipment was obtained by asking each grower to estimate the market value of bearing orchards, buildings used in the growing phase of the business and equipment used to grow the apple crop. The return on investment for the orchards and buildings is included in the orchard overhead group. The return on investment for the equipment is included under equipment on Table 2. The real estate tax represents the taxes actually paid on the bearing orchards and the taxes on the buildings used to store growing equipment and materials. In most cases it was necessary to break these out from a total tax bill. Rentals includes the payment made for orchards or buildings not owned by the grower. Five of the participating growers rent some orchards and/or buildings. The category "other" under orchard overhead in Table 2 includes insurance, short term interest, and any miscellaneous cost associated with the growing phase of the business. The short term interest includes only the interest on loans made to produce the crop, typically they might include loans for pruning, materials, etc. It does not include interest on loans for the purchase of equipment, buildings, orchards, etc. This type of interest would be covered under the return on investment. The labor costs in Table 2 includes the gross wages paid the employee plus the employer's share of social security, workmen's compensation, unemployment insurance and the cash cost of any fringe benefits. Harvesting Cost Table 3 illustrates the costs associated with the harvest operation. Many of these costs, unlike those in the growing costs, vary directly with the amount of fruit harvested. Therefore, they are shown on a per bushel basis, rather than a per acre basis. The picking and other labor categories includes the gross wages paid for harvesting apples plus any bonus and/or incentives. They also include the employer's share of social security, workmen's compensation, unemployment insurance and any other benefits paid other than housing and transportation. The harvesting costs include the cost of harvesting all fruit, including drops. -15- Summary The average 1983 growing cost was $1,231.61 per bearing acre. This was up 12% from $1,100.97 in 1982. Most of this increase can be attributed to the weather experienced throughout the 1983 growing season. The major increase occurred in the labor and materials categories. The mild winter we experienced allowed growers to prune more trees which increased the amount of labor cost associated with pruning and brush removal. The cold, wet spring made it necessary for a number of growers to apply more fungicides. The very hot and dry period of July, August, and early September caused a number of growers to increase their use of insecticides and miticides. This same weather pattern also meant that many growers had to irrigate more than in past years. The average per bushel growing cost was $2.67 in 1983 as compared to $2.10 in 1982. This increase of 27% was due in part to the increase in the per acre costs but more importantly to a decrease of 64 bushels in the average yield per acre. This yield decrease can also be attributed at least in part to the weather. The harvesting cost for 1983 was $1.50, approximately the same as the $1.48 in 1982. The combined growing and harvesting cost for 1983 was $4.17 as compared to $3.58 in 1982 and $4.25 in 1981. The major reason for the changes in the per bushel costs over the past three years has been the fluctuation in the average yield. Fruit Quality It should be remembered that these figures are an attempt to measure the cost of growing and harvesting apples. One major factor, which impacts the profitability of an operation, which has not been discussed, is fruit quality. This is a factor which growers cannot afford to overlook when they are evaluating their yields and costs. It is very possible for a grower with higher production per acre and lower costs to be less profitable than his neighbor. This is because the increase in production and reduction in costs may come at the expense of quality. In using the figures contained in this article to analyze his business, a grower must keep the concern for fruit quality foremost in mind. A growers ability to produce high quality fruit at a reasonable cost will determine his success. Table 1. Eight operations, 1983 -16- Total acres of apples Acres of bearing apples Percent of non-bearing Total 1,936 1,558 Average 242 195 20 Range 41-585 21-473 7-49 Tree age (% of total acreage) 1-5 years 6-10 years 11-15 years 16-20 years 21-30 years over 30 years 24 23 9 14 11 19 6-59 2-38 2-20 0-25 1-20 0-39 Apples harvested (bu.) Picked fruit Drops 717,615 640,598 77,017 89 80 9 ,702 ,075 ,627 10 10, ,385-162,115 151-154,175 234-28,561 Total estimated crop 724,615 90 ,577 10 ,885-162,115 Percent of crop harvested 99 95-100 Yield per acre (bu. harvested) 461 343-685 Percentage of crop harvested as drops 11 2-23 Number of bearing acres pruned Dormant Summer 1,268 783 159 98 NA NA Percentage of bearing acres pruned Dormant Summer 81 50 31-100 0-100 Average number of sprays per acre 13.5 10-17 Number of bearing acres receiving herbicides 161 20-473 Average number of times mowed 3.8 3-5 Number of acres irrigated 347 43 0-180 Average number of times acres irrigated 1.23 NA -17- Table 2. Growing cost (dollars per bearing acre) eight operations, 1983 Orchard overhead Real estate tax Return on investment Rental Other Management Salary Accounting/secretarial Office expense Labor Pruning & brush removal Spraying Orchard floor management Irrigation Other Equipment Depreciation Return on investment Fuel Repairs & maintenance Other Materials Fungicides Insecticides Miticides Spray oil Growth regulators Herbicides Lime and fertilizer Other Total Total Total Total Total Total growing cost per bearing acre Yield per acre (bu.) Cost per bushel Average $23.37 214.82 18.31 50.59 $307.09 $113.87 $273.66 Range $15.08 - 28.30 83.52 - 545.14 0.00 - 98.34 8.00 - 113.81 $206.85 - 662.67 $86.41 $34.15 - 187.07 22.73 5.13 - 87.17 4.73 2.37 - 11.76 $55.99 - 276.61 $147.10 $77.02- 233.00 38.14 12.55 - 56.48 30.07 15.30 - 55.07 8.29 0.00 - 49.71 50.06 9.44 - 146.15 $166.31 - 366.00 $50.33 $31.34 - 112.10 60.40 37.61 - 134.52 47.79 16.28 - 68.81 75.32 34.21 - 105.71 7.60 0.00 - 13.00 $241.44 $157.08 - 409.81 $75.93 $49.99 - 115.38 54.32 30.25 - 90.32 53.13 36.49 - 77.38 6.71 0.00 - 17.61 29.53 17.10 - 44.80 8.88 2.18 - 16.89 28.57 7.56 - 49.21 38.48 13.42 - 68.86 $295.55 $209.67 - 441.32 $1,231.61 $977.43 -1,836.38 461 343 - 685 $2.67 $1.72 - 3.96 -18- Table 3. Harvesting costs (dollars per bushel) , eight operations, 1983. Equipment Depreciation Return on investment Fuel Repairs and maintenance Other Total Containers Depreciation Return on investment Repair and maintenance Total Housing for pickers Depreciation Return on investment Repairs and maintenance Insurance Fuel and electrical Real estate tax Supplies Total Picking Labor Picker transportation Other labor Supervision Fruit handling Accounting/secretarial Total Other harvesting costs Total harvesting cost per bushel Average .03 .04 .03 .04 .02 .16" .09 .10 .03 ~J2 .02 .06 .03 * .02 .01 .01 lis" .59 .09 .13 .11 .02 'J26 .03 1.50 Range .02 - .06 .03 - .08 .01 - .05 * .10 * .06 .07 - .33 .05 - .12 .06 - .14 * _ .11 .13 - .30 * .05 .01 - .12 * .10 * * .01 - .05 .00 - .01 * _ .01 .07 - .30 .48 - .87 .03 - .13 .05 - .23 .07 - .17 * _ .05 .14 - .40 .00 - .08 1.12 - 1.98 Less than .01 per bushel -19- DAILY ACTIVITY OF APPLE BLOTCH LEAFMINER ADULTS^ T.A. Green and R.J. Prokopy Department of Entomology Over the past 8 years, the Apple Blotch Leafminer (ABLM), Phyllonorycter crataegella, has become a serious pest in commercial apple orchards east of the Hudson River, High populations of this organophosphate resistant insect have been associated with reduced fruit size, premature fruit ripening, and reduced fruit set the following year in some cultivars. In a previous issue of FRUIT NOTES (Spring, 1983) we reported on the development of a visual monitoring trap for ABLM adults. Concurrent with that work, we conducted a study of the behavior of ABLM moths in and around commercial apple orchards. Our study has thus far been restricted to the second and third adult flights, occurring in early July and late August, respectively. To determine the location and activity of ABLM adults, we performed 1 minute observations of various tree structures including the upper leaf surface, lower leaf surface, fruit, trunk, and ground cover, at 1 hour intervals. We recorded the numbers of ABLM observed at each location. In like fashion, we observed the tree canopy for flight activity. Our results are presented in Figure 1. We found the primary location of stationary ABLM throughout the day to be the lower leaf surface. We observed a number of mating pairs, again predominantly on the lower leaf surface, and exclusively before 11:00 AM. We also observed several ovipositing females, all on the lower leaf surface, and all in the late afternoon and evening. We found flight activity to be concentrated during two periods of the day, from sunrise to 3-4 hours after sunrise, and from 3-4 hours before sunset to sunset. The number of flights observed per minute during the AM flight period was approximately 2.5 times that of the PM flight period. During the AM flight, landings on the upper leaf surface outnumbered lower leaf surface landings by a 2 to 1 margin. This ratio was reversed in the evening. To further investigate the differences observed between the two flight periods, we captured flying ABLM and determined their sex. We employed three capture methods: ^ We wish to express our appreciation to research assistants Geoffrey Hubell and Martin Rose, and to the following families for use of their orchards: Jack DeLuca, Ed Roberts, Dave Shearer, Harvey and Marvin Peck, Ray Davis, and Cameron Sewell (in New Hampshire). -20- visual traps; net sweeps; and captures of moths by an aspirator immediately after landing. These results are presented in Figure 2. All three methods indicated that the AM flights were virtually all made by males, whereas the PM flights were made predominantly by female moths. We found the same general pattern of activity to occur on non-host trees adjacent to orchards, but far fewer ABLM and no ovipositions were observed there. In summary, then, our study indicates that at least during the second and third generations, male ABLM moths fly from first light to approximately 9-10 AM, probably searching for females to mate. Virtually all mating occurs during this time. This strategy may be designed to minimize wind disruption of sex pheromone trails emitted by females, by taking advantage of the lower wind speeds usually associated with this time of day. From mid-morning to approximately 5 PM, ABLM adults are largely inactive and are located in relatively concealed and shaded areas, possibly to avoid desiccation and predation. In the evening, females are in flight, probably foraging for ovipostion sites. On the basis of our results, we recommend that insecticide applications for adult ABLM be timed to coincide with the evening flight period. This will maximize both the effectiveness of any fumigant action and contact of females with fresh insecticide. This season we plan to investigate the effect of temperature on oviposition rates, and to extend our observations to the overwintering generation of adults. I -L -21- 22.87 Number . ABLM ' Dbserved Sunrise 0 10 AM I 1 I i 9.24 iQ Number , ABLM ' Observed 10 AM to 5 PM 1 JZZL nn 8.24 lea 8.81 Number ABLM 3 Observed 5 PM to Sunset . Lower Leaf Surface Upper Leaf Surface Fruit Trunk Ground Cover Flight Figure 1. Number of ABLM adults observed per minute at various locations during three different time periods. -22- -L 5.13 Number 2 of ABLM Captures Sunrise to 10 AM 1 cTU 9^ K33L Number of ABLM Captures 5 PM to Sunset :si ^ :^ :^ I — ^ _ r> . Sweep Net . Trap Captures Captures Aspirations Per Hour Per Minute Per Minute Figure 2. Number of ABLM adults captured by three different methods during morning and evening flight periods. a UJ O •; (J) CVJ .- °< oS - t- O 2 < ° O < t: f. 11. a. CL E t; E < O M CO ji CO t') 5i Q. ro «— O ^ < S- s; E E S Q LL D < PO I FRUIT pr 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 49 No. 4 FALL ISSUE, 1984 Table of Contents Fruit Notes Subscription Bigger Apples, Less Calcium, More Problems Photographs of Nutrient Deficiencies and Toxicities and Heat Stress Pomological Paragraph — New Apple Rootstock Available The Consumer's View of Fresh Pears Pomological Paragraph — Harvest Indices Do Fungicide Residues Affect Apple Maggot Fly Egglaying? Effects of Rootstock and Stempiece/Rootstock Combinations on Growth, Leaf Mineral Concentrations, Yield and Fruit Quality of "Empire" Apple Trees 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 The Fall Issue of FRUIT NOTES is the 4th and last issue for the year. Now is the time to renew your subscription for 1985. The question has been asked about multi-year subscriptions. This would be desirable but the Editor of FRUIT NOTES retires in 1985 and the fate of this publication after this date is unknown. To subscribe to FRUIT NOTES complete and mail the following form with your check for $3.00. (Canadian subscribers please send a U.S. postal money order.) William J. Lord Editor, FRUIT NOTES Name Mailing address_ Town, State, Country Zip Make checks payable to: FRUIT NOTES ACTIVITY ACCOUNT. Send subscription form and check to: William J. Lord Department of Plant and Soil Sciences French Hall University of Massachusetts Amherst, MA 01003 -2- BIGGER APPLES, LESS CALCIUM, MORE PROBLEMS William J. Bramlage Department of Plant and Soil Sciences It has frequently been observed that large apples do not store as well as small apples within a given variety. When storage problems occur, they tend to be much more prevalent on the largest apples within a box. This relationship of storage disorders with fruit size is largely a reflection of the fact that within a sample of fruit, calcium (Ca) concentrations are lower within the larger fruit. For example, Dr. Mack Drake recently analyzed some random samples of different sizes of packed Mcintosh apples. The results (Table 1) showed a marked reduction of fruit Ca as size increased. We have seen many times that differences in Ca concentration of this magnitude can lead to quite different amounts of breakdown, rot, bitter pit, and even scald on Mcintosh after storage. Table 1. Calcium concentration in Mcintosh apples of different sizes, 1983. Box Fruit Average Ca concentration^ count circumference fruit weight (ppm dry wt.) (g) Fruit circumference (inches) 2 .5 - 2 6 2 .7 - 2 8 2 .9 - 3 .0 3 .1 - 3 .2 160 2.5 - 2.6 100 129 140 2.7 - 2.8 122 119 120 2.9 - 3.0 154 HI 96 3.1 - 3.2 186 90 ^Ca concentration in outer cortex tissue on calyx half of the fruit. The relationship between fruit size and fruit Ca concentration in apples has been studied extensively by Michael A. Perring at the East Mailing Research Station, Kent, England. In bulk samples, he has found that the relationship is very dramatic (Figure 1). The main reason for larger fruit having lower Ca concentrations is that the amount of Ca transported by the tree into developing apples is very small, and as apples enlarge their cells get larger and the concentration of Ca in them becomes diluted by water and other cellular constituents. Large apples have larger cells, hence their Ca is more diluted. Another reason for the fruit size: Ca relationship is that relatively large fruit generally come from low-yielding trees, or areas of trees. With light cropping more vegetation is produced, and what Ca is available in the tree is preferentially -3- transported to the vegetation; in general, the more vegetation there is per apple, the less Ca is available for the fruit. The pattern shown in Figure 1 can be expected when examining bulk samples of apples. However, when you measure individual apples the pattern is not as distinct (Perring and Jackson). A large apple does not always have a low Ca concentration, and a small apple does not always have a high Ca concentration. I 20 H— O g E O 3 O _) < ■ •••■»;•' • •-. .-• • >.'; • v. -.•...•.•:•■ •..'.■ -L 50 100 150 MEAN WEIGHT PER APPLE (g) 200 -4- even when the fruit all come from the same tree on the same date. Obviously, there are factors that affect the movement of Ca into individual apples, since apples of a given size and variety can vary considerably in the total amount of Ca they contain (Perring and Jackson). Perhaps the most dramatic variation from this pattern is found with very small apples. Perring has observed that very small apples (which should have high Ca) sometimes are heavily afflicted with bitter pit. We have also observed that very small Mcintosh and Delicious are sometimes severely broken down. We have also noted that these small apples with breakdown often contain no, or almost no, plump seeds, and in a recent study we found that in Delicious, fruit Ca concentration decreased as seed number decreased, even when the fruit were all the same size. We have also noted that Mcintosh with few or no seeds tend to mature earlier than ones with many seeds, as as is well known, more mature fruit tend to deteriorate faster than less mature fruit. Thus, seed number may be one cause of the variation in Ca concentration among fruit of a given size. Poor pollination may contribute to low fruit Ca. The absolute relationship between apple size and Ca concentration changes somewhat from year to year (Perring and Jackson) and also varies considerably from variety to variety (Perring), even when bulk samples are analyzed. For example, Perring found that for a given size of fruit, Mutsu contained a higher Ca concentration than did Cox, although in both varieties the general pattern of Figure 1 was displayed. These findings demonstrate that while there is not an absolute fruit size: fruit Ca relationship, there certainly is a strong and highly important general relationship. When growing conditions are such that average fruit size is increased for a variety, average fruit Ca can be expected to be lowered, and with this lowering of fruit Ca concentration there is increased potential for fruit disorders during and after storage. This situation creates a paradox for apple growers. Production of larger fruit can increase yield substantially, thereby increasing potential income substantially. However, this greater fruit size creates a greater Ca problem, and needs to be accompanied by remedial actions to prevent reduced storage life of the fruit that have been produced. Production of larger fruit increases then need for foliar applications of Ca and/or for postharvest Ca treatments to the fruit. It is the opinion of many investigators that the "calcium problem" of apples that exists world-wide today is one that has been created by intensive production methods that have increased average fruit size and yield. It is unlikely that the need for high productivity will diminish with time, and so it is also unlikely that the need for Ca treatments will diminish with time. Literature Cited 1. Perring, M.A. 1979. The effects of environment and cultural practices on cal- cium concentration in the apple fruit. Commun. Soil Science and Plant Anal. 10:279-29 3. 2. Perring, M.A. and C.H. Jackson. 19 75. The mineral composition of apples. Calcium concentration and bitter pit in relation to mean mass per apple. J. Sci. Food Agric. 26:149 3-1502. -5- PHOTOGRAPHS OF NUTRIENT DEFICIENCIES AND TOXICITIES AND HEAT STRESS William J. Lord Department of Plant and Soil Sciences In the past, we occasionally published in FRUIT NOTES photographs of nutrient deficiencies. Last year when we had numerous problems - severe scab outbreak in some orchards, hail, russetted apples, small fruit, an extremely wet spring, a dry summer, slow color development on fruit of some varieties, etc. - it became apparent that confusion existed concerning nutrient deficiency symptoms. Deficiency symptoms recognition that caused problems were mainly boron (B), potassium (K) and magnesium (Mg). Therefore, for your information we have again published photographs and brief descriptions of some nutrient deficiencies of apples and pears. Calcium (Ca). Bitter pit and cork spot are visual evidence of low Ca in apples and are more prevalent on some varieties and years than others. Bitter pit is common on Cortland, Baldwin and Northern Spy whereas cork spot is much less prevalent but can be found on Delicious and Golden Delicious in New England. The Delicious on the left in Figure 1 shows bitter pit and the one on the right Figure 1. Symptoms of calcium deficiency on Delicious fruit. -6- has cork spot. Bitter pit is most frequently associated with the calyx end of the apple and its severity may increase in storage. Cork spot is not localized and will appear anywhere on the apple. The spots are more pronounced than bitter pit, being much deeper and wider. In some cases the cork spot resembles the inner cone of a miniature volcano, with the depressed skin area containing green or dark red pigment. Cork spot does not increase in severity in storage. Magnesium (Mg) Deficiency. Mg deficiency of apple and pear trees has been more prevalent in orchards the last 2 years probably due to excessive rainfall early in the growing season. These visual observations were supported by leaf analysis which indicates that Mg is exceptionally low in some instances. Mg symptoms are characterized necrotic (brown) areas between the veins (Figures 2, 3). The older basal leaves on shoots and spurs are usually affected first and as the Figure 2. Magnesium deficiency symptoms on apple leaves. -7- season progresses the injury symptoms appear on the younger leaves. The deficiency symptoms frequently become apparent in late July and early August. By late summer, the shoots on which leaves show Mg deficiency may be defoliated except for a few leaves near their terminals. Mg deficiency increases fruit drop at harvest. Figure 3. Magneisum deficiency symptoms on pear leaves. Figure 4. Heat stress symptoms on pear foliage. -8- Heat stress symptoms on pear foliage (Figure 4) are sometimes confused with Mg deficiency. Symptoms of heat stress (scorch) appear suddenly after a period of intense heat. The scorch generally can be found on spur and terminal leaves of several or more branches throughout the trees, the leaves being partially brown or black. There is no progression of symptoms from the older to the most recently-formed leaves on terminal shoots as with Mg deficiency. Frequently, the majority of injured leaves drop as the growing season progresses. The Bosc variety may be more susceptible to heat stress than other pear varieties commonly grown in New England. Potassium (K). Figure 5 shows leaf margin burn caused by K deficiency. This symptom can be easily confused with the leaf margin burn from calcium chloride sprays and sometimes confused with Mg deficiency. However, unlike leaf burn from calcium chloride sprays, the scorch of leaf margins due to K deficiency progresses from the older leaves to the younger leaves of current season shoots as the season advances. The scorch may turn gray in color. Fraying and tattering of the leaves may occur due to loss of the dead areas along their margins. When the deficiency is severe leaf drop commencing with the older leaves of current season's terminal growth, is evident in the latter part of the growing season. Nevertheless, leaf analysis is sometimes necessary to confirm the problem is K and not calcium chloride burn. Figure 5. Potassium deficiency symptoms on apple leaves. Total K absorbed and the total dry matter produced is similar for fruiting and non-fruiting trees but in heavy-cropping trees is translocated into the fruits. Thus, the demand of a large crop for K is great and both the tree and fruit may be deficient in this element. Leaf injury because of K deficiency can cause pre-harvest drop and reduce fruit size. In contrast, light cropping trees are probably much higher in K than is needed because of "luxury" uptake. K deficiency symptoms are apt to be more frequent in dry years because drought conditions reduces uptake of elements. -9- Boron Toxicity (B). Toxicity symptoms of this element are observed in a few orchards each year. Symptoms occur on bearing trees sprayed with a foliar application of B, on trees fertilized with B the year of planting, or bearing trees that received excessive rates of B containing fertilizer. Figure 6 shows typical foliar symptoms of B toxicity. The symptoms are characterized by loss of chlorophyll (green coloration) from along the midrib and larger lateral veins. The symptoms are first apparent at the base of the leaf blade. In severe cases, loss of chlorophyU is more extensive than shown in the picture. Boron Deficiency (B). Occasionally B deficiency is so acute in pear trees that the fruits become malformed and cracked (Figure 7). B deficiency on apple trees is less common than B toxicity. It is very easy to prevent, thus it is embarassing to have the disorder. It certainly hurts financially because all the fruit where deficiency exist should be sold only for cider. The most common symptom of B deficiency is found internal in fruit being characterized by brown, round or irregular shaped lesions of about 5 inch diameter (Figure 8). The dead cell masses become dry, hard and corky before harvest. Fruit affected with the disorder will have a pebbled surface (particularly noticeable on Cortland), open calyx, and abnormally dark color as they mature. However, frequently the first recognition of the problem is excessive preharvest drop. Figure 6. Boron toxicity symptoms on apple leaves. -10- Figure 7. Symptoms of boron deficiency in pear fruit. -u- Manganese Deficiency (Mn). This element is found deficient in several orchards each summer. As shown in Figure 9, apple leaves having Mn deficiency have interveinal fading of chlorophyll with the veins remaining green. In the past we have analyzed Mcintosh apple leaves from trees showing Mn deficiency and found the leaf of this element to be 9 to 14 ppm. Mn levels of this magnitude are critically low in comparison to the desired standard of 50-100 ppm set by other states for apple trees. Manganese Toxicity (Mn) is implicated with the problem of "apple measles" shown in Figure 10. The twig from Delicious at the top of the photograph shows severe symptoms of measles while the twig below has normal bark. Measles can severely injure or kill young Delicious trees. An over-application of a dormant-oil spray can induce symptoms similar to that shown in Figure 10. Figure 9. Symptoms of manganese toxicity on apple leaves. -12- Figure 10. Bark on three year-old wood from Delicious trees showing measles (top of photograph) as compared to normal bark (bottom of photograph). :jc])e:te:jt:je4:3(c^^4:3t: POMOLOGICAL PARAGRAPH William J. Lord Department of Plant and Soil Sciences New Apple Rootstock Will Soon Be Available. Mark a new size-controlling rootstock, one of a series of rootstocks developed by Dr. Robert Carlson, Michigan State University, Professor emeritus of Horticulture, will soon be commercially available. Trees on Mark (formerly designated MAC-9) are reported to be well-anchored, precocious and between M9 and M26 in size. Thus, Mark under Michigan conditions, shows great promise as a size-controlling rootstock that enhances early fruit production and requires no support because of poor anchorage or brittle roots. We have Starkspur Supreme Delicious on Mark at our Horticultural Research Station in Belchertown but the trees are only 4 years old. Nevertheless, the trees on Mark presently appear to be well anchored, precocious and somewhat larger than those on M26. In contrast, unsupported Starkspur Supreme Delicious trees on M9 or EMLA27 are leaning badly or have broke at the scion-rootstock union. It is reported that limited quantities of trees on Mark will be available for purchase during the winter of 19 86-87. By this time Mark will have been more thoroughly tested because it has been included in the North Central Region Cooperative Rootstock Trial established in 1980-81 at 25 locations in the United States and 2 in Canada. -13- The Consumer's View of Fresh Pears William J. Bramlage Department of Plant and Soil Sciences A ripe pear can be a true delicacy, yet consumption of pears ranks far below that of fruits such as oranges, apples, and bananas. Why don't we eat more pears? A very interesting picture emerges from a study conducted in England, entitled "The Pear Situation 1976" and published by The Apple and Pear Development Council. As a part of this study housewives who were regular buyers of fruit were interviewed, including ones who purchased pears frequently, irre- gularly, or not at all . Why buy pears? Consumers purchased fruit for the following purposes: as a dessert; as a snack; for inclusion in lunch boxes or picnic baskets; and for casual eating, such as while watching TV. The main reasons for not ordinarily purchasing pears were that the consumers either did not like them or because they considered pears unsuitable for certain of these purposes, especially for inclusion in lunch boxes and for casual eating. Pears were considered unsuitable for lunch boxes primarily because they were thought to be too fragile, while the main objection to them for casual eating was that you cannot casually eat a ripe pear! Unlike apples or bananas, pears usually require a plate, a knife, and a napkin when eaten. This point was emphasized by mothers with young children, who felt that the most satisfactory way to serve pears to a child was to peel, slice, and core the fruit. Selecti on. In the store the consumers were searching for a basis on which to predict the quality of pears. The most obvious possibilities are the appearance and the variety name. However, variety names are not conspicuously promoted and even when they are few consumers have sufficient knowledge to relate quality with variety. Therefore, appearance is the al 1 -important factor in choice of pears. Yet, consumers had little understanding of what to expect from a pear's appearance. As a result, purchase of pears was very risky. Many of those interviewed were unwilling to subject themselves to criticism from the rest of the family, so they tended to avoid this risk and make a "safe" purchase of other fruit. What is so unpredictable about pears? First, their tendency to be hard when the consumer wants them to be soft. A substantial portion of those inter- viewed had little idea that pears could be ripened in the home, much less knowledge of how to ripen them. Second, there was little perception of exactly when a pear should be eaten. Therefore, when pears were purchased it was only in small quantities and if the purchase proved disappointing the buyer usually skinned pears for some time afterward. Acceptabi lity . Consumers were generally well aware of the health-giving properties of apples and oranges, but they questioned the nutritional value of pears. Housewives were particularly anxious to provide their children with good, wholesome, fresh fruit and were unclear of the nutritional role of pears. There was also an image that pears tend to be more expensive than apples, for example, and that pears therefore were a luxury item. This image plus the uncertainty of quality were strong deterrents to regular purchases of pears. -14- Quite interestingly, there was strong indication that favorable disposition to pears was often acquired early in life. Many of the consumers who were enthusiastic ai^out pears were strongly encouraged to eat them as children. Children were particularly strong motivators of fruit purchase, so it seemed reasonable to conclude that pear buying would be stimulated by giving mothers a good reason for buying them for their children. The Ideal Pear. The housewives interviewed found it much easier to describe what they did not like about pears than what they did like. The most prominent dislikes were dryness and hardness, commonly thought to go together. Other prominent dislikes were grittiness, tendency for bruises to appear during ripening, and browning in the core. The majority of those interviewed were seeking a pear that had an attrac- tive smooth skin, was juicy, and had a smooth internal texture. (It should be noted, though, that some consumers prefer hard pears, and that in the U.S. there is reputed to be a growing preference for hard green peas among young consumers.) There was a preference for clear skinned, green to yellow pears with a true "pear shape", and opposition to ones with a brown ground color, which was associated with tough pears having a leathery skin. Conci usions . Although this study was conducted in England and is about 10 years old, it is likely that the perceptions revealed by the interviews are widespread and still relevant. The study strongly suggests that pear sales and consumption could be improved considerably by better promotion and information, and especially by providing the consumer with more consistent quality, and with information about how to handle pears once they have been purchased. POMOLOGICAL PARAGRAPH Wil 1 iam J. Lord Department of Plant and Soil Sciences Harvest Indices. Changes in firmness of flesh, surface color, seed color, size of fruit, ground color, ease of separation from spur, days from full bloom, the Starch-Iodine test, calendar date and ethylene production are indices of maturity that a grower may follow to determine when to harvest his apples. Ethylene level in the fruits clearly is the best measure to assess maturity, ripening and storability but our experiences with a portable instrument to measure this gas has been less than satisfactory. Among the indices that are of little or no value are seed color, fruit size and fruit color. The seeds may change color from light green to brown weeks before other indices indicate picking maturity. Surface color is of no value with red strains because their entire surface may redden when still wery immature. Recently, there has been renewed interest in using the Starch-Iodine Test for evaluating apple maturity. As apples mature and ripen, the starch in the imma- ture fruit changes to sugar. This decreasing level of starch can be measured by treating the fruit with an iodine solution. Contact your Regional Fruit Specialist for further information concerning the Starch-Iodine tests. Picking at the proper stage of maturity is particularly important if the fruit is to be stored. But this is confounded by color required for sale, type of storage and length of storage. Therefore, there is no such thing as optimum maturity stage for all fruit. Fruit for long-term storage should be harvested and stored before they gain the capacity to produce large quantities of ethy- lene. However, those intended for shorter storage can and should be allowed to remain on the trees longer to gain extra quality and sales appeal. -15- DO FUNGICIDE RESIDUES AFFECT APPLE MAGGOT FLY EGGLAYING? Susan B. Oppl, Susan L. Butkewich^, and Ronald J. Prokopy-^ Department of Entomology In previous issues of FRUIT NOTES, we described some of our studies on the effects of various substances on apple maggot fly egglaying. For example, we found that a substance (pheromone) released by female flies following egglaying deters other females from attempting to lay an egg in that fruit (Vol. 42, No. 1). We also found that sodium chloride (table salt) Vol. 45, No. 5) and acid rain (Vol. 48, No. 4) deter egglaying, while calcium chloride has no such effect (Vol. 45, No. 5). Recently, we decided to test some of the fungicides commonly applied to apples to control mid- to late-season diseases for possible effects of their residues on apple maggot fly egglaying. We felt that an egglaying deterrence from fungicides applied during the months of peak apple maggot fly activity might affect grower choice of fungicides for use against diseases. We tested at field rates 9 organic fungicides currently recommended for apples and 1 fungicide (Bordeaux mixture) no longer applied to apples. Unfortunately, our laboratory trials showed no effects of any of the organic fungicides on apple maggot fly egglaying. Only the inorganic fungicide Bordeaux mixture significantly deterred fly egglaying (Table 1). Before the introduction of organic fungicides, Bordeaux mixture was widely used as an orchard fungicide. However, it is phytotoxic and is not compatible with many other pesticides, and thus is no longer recommended for orchard use. It is also interesting to note that even the fungicides which left visibly heavy residues on test fruit (such as sulfur) or had a disagreeable odor (such as fenarimol ) did not deter fly egglaying. We are reminded that insects may react in ways which differ dramatically from what we might expect. Graduate student. Entomology Extension Technician ^ Extension Entomologist -16- Table 1. Percent of arriving females attempting egglaying into hawthorn fruits treated with fungicide or spring water control. Experiment Rate of formulated Egglaying material (lb/100 gal ) attempts (%) 1) Control - 39.2 Captan (50WP) 2.0 49.1 2) Control - 58.2 Maneb (80WP) 1.5 62.5 Dodine (65WP) 0.375 54.2 3) Control - 42.8 Benomyl (50WP) 0.375 43.8 Sulfur (actual ) 5.0 56.6 4) Control - 67.5 Thiram (65WP) 2.0 67.3 5) Control - 65.4 Metiram (80WP) 2.0 49.1 Dikar (80WP) 2.0 60.0 6) Control - 49.2 Ferbam (76WP) 1.5 70.0 Fenarimol (12.5EC) 3 oz. 50.9 7) Control - 66.7 Bordeaux mi xture 3-11 12.1* (copper sulfate-1 ime) *Significantly less than egglaying into control fruits. -17- Effects of Rootstock and Stempiece/Rootstock Combinations on Growth, Leaf Mineral Concentrations, Yield and Fruit Quality of 'Empire' Apple Trees! W.J. Lord, D.W. Greene, R.A. Damon, Jr. and J.H. Baker University of Massachusetts, Amherst 01003 A study of 8-year duration was recently completed in which we studied the vegetative growth, leaf mineral concentrations, fruiting and fruit quality responses of 'Empire' apple trees on M26, M9, M27, M9/MM106, M9/MM111, M27/MM106 and M27/MM111. The stempieces were 8 inches (20 cm) in length. Our summary and conclusions from this study are below. Growth. It was difficult to train, without temporary support, trees on M26, 9/106, 9/111, 27/106 and 27/111 because of leader leaning. Leader leaning appeared associated with the growth characteristic of 'Empire' rather than an excessive crop load. Since this problem also has been encountered with other varieties on M26 or interstems, we concluded that it may be frequently necessary to provide support for the central leader until the trees have obtained the height and volume desired. Interstem trees on MMlll produced more root suckers than those with MM106 as the understock. Trees on M27 produced no root suckers. The root suckering was not particularly troublesome on the interstem trees probably because all but 2 inches of the stempiece was planted below ground and maintained by periodic removal or addition of top soil. Costante et al. in Vermont showed that interstem trees planted with most of the stempiece beneath ground had less root suckers and problems associated with burrknots on the stempieces. Height and spread of trees on M26, 9/106, 9/111, 27/106 and 27/111 were similar, and they were larger than those on M9 and M27. The data disagreed with the suggestion by nurserymen that a M27 stempiece on either MM106 or MMlll will produce a tree approximately the size of the same cultivar on M9 rootstock. M27 appears too dwarfing to be of value under less than extremely favorable growing conditions and a high level of management. However, Tukey in Pennsylvania predicts off bright future for this rootstock as the industry shifts to virus-tested rootstocks which induce high vigor. Leaf mineral concentrations. The rootstock and stempiece/rootstock combinations influenced leaf phosphorous, magnesium, boron, manganese, and aluminum in 'Empire' scion foliage but the differences were small except for manganese levels in trees on M27. Manganese level in leaves from trees on M27 was much higher than those for trees on the other rootstock and stempiece/rootstock combinations. This study was funded in part by grants from the International Dwarf Fruit Tree Association. -18- Effects of rootstock on nutrient uptake and movement may vary among locations due to orchard conditions, tree age, variety and crop load. Nevertheless, appropriate preventative measures may be necessary before planting trees on M27 rootstocks where manganese has been associated with internal bark necrosis on Delicious apple trees. Fruitfulness and fruit size. No rootstock or stempiece/rootstock combination consistently influenced bloom or fruit set although it is well known that M9 rootstock can induce early precocity and limited data show that rootstocks can influence fruit set. The trees fruited in their 3rd growing season but yields were low until the 6th growing season. After 8 growing seasons it was found that trees on M26, 9/106 and 27/106 were more productive than those on 9/111, 1V19 and M27. However, when fruitfulness was related to trunk girth, production efficiency did not differ among the trees on the various rootstock and stempiece/rootstock combinations. There was no consistent influence of rootstock or stempiece/rootstock combinations on fruit size of 'Empire' in this study. Individual trees within the rootstock and stempiece/rootstocks combinations became somewhat biennial. Heavy cropping during the 7th or 8th growing seasons combined with the tendency of 'Empire' to produce small fruit, indicated the need to chemically thin this variety to enhance fruit size and to prevent biennial bearing. Fruit maturity. Fruit from trees on 27/111 ripened later than those from trees on the other rootstock and stempiece/rootstock combinations. However, the delay in ripening was small and probably of no commercial importance. Data cited above indicated that IV127 and M9 were equally suitable as stempieces. No interstem combination showed an advantage over the lower-priced singly-worked trees on M26 although MMlll is reported to be adapted to a greater variety of soils than M26. We concluded that interstem trees will require a higher level of management that is usually given trees on more vigorous size-controlling rootstocks in northeastern United States. w>C-no ■& -J. on ■* -» OJ X SS 3 = § iS a "* o ■ SI 3 t n > 3 C2 3982' 060 o o to 3 ■03; 0 to - Si ACME BOOKRlNOiNG CO.. INC. JUL 1 6 1987 100 CAMemOGE STREET CHA^