This project developed methods for management of key apple pests – flyspeck (Schizothyrium pomi), European red mite (Panonychus ulmi), plum curculio (Conotrachelus nenuphar), and apple maggot (Rhagoletis pomonella) – in Northeastern apple orchards using advanced, biologically intensive methods. The third-level integrated pest management approach also examined susceptibility of new apple cultivars to these pests. The goal of the project was further reduction of pesticide use using methods that are economically viable. To a large extent, this was accomplished through development of insect monitoring and trapping methods, introduction of a mite predator, and describing the epidemiology of a key summer disease. Through integration of over twenty years of research in apple IPM, projects running concurrently with this one, we developed effective attractants and trapping methods for plum curculio, a killing trap for the apple maggot fly, and a model to more effectively and efficiently direct fungicide treatments for flyspeck. Screening of scab-resistant cultivars in a test block indicated that Scarlet O’hara, Pristine and Goldrush have good commercial potential. Of non-resistant new cultivars, Honeycrisp and Cameo show consistent promise. Growers have been receptive to the new methods.
Apple production in the northeastern states is important both economically and culturally. It has also been a model system for the development and implementation of integrated pest management, funded in part by SARE projects, particularly over a twenty-year period in Massachusetts. This project worked on development and adoption of third-level IPM principles. We view third-level apple IPM as the confluence of bio-intensive, cross-disciplinary pest management and all horticultural practices, yielding management consistent with the principles of sustainable agriculture. Development and use of such a system for apple production in the Northeast will demonstrate the potential to do so in other crops that may now use large amounts of chemical input. It will also contribute to economic viability of apple production in the region.
Although adoption of first- and second-level apple IPM results in substantial reduction in pesticide use (30% and 50%, respectively, apple production in the Northeast still requires fairly extensive pesticide input. Five pests have been identified as major hurdles in advancing sustainable management systems in Northeast apple production. These pests are the diseases apple scab (Venturia inaequalis) and flyspeck (Schizothyrium pomi), European red mite (Panonychus ulmi), plum curculio (Conotrachelus nenuphar), and apple maggot (Rhagoletis pomonella). Together, these pests account for more than 90% of total pesticide used under first-level IPM. Significant work in the region has been done in pursuit of sustainable management of apple scab, and work in another SARE-funded project examined the potential for early scab-resistant apples. While this project examined more scab-resistant cultivars in a test block, it focused on the remaining 4 key apple pests. Developing a more advanced, less chemically reliant management system to deal with these 4 pests will significantly reduce the need for fungicides, miticides, and insecticides on apples in the Northeast.
In addition to growing the healthiest possible fruit under the most environmentally sound principles, another factor that plays a crucial role in the future survival and flourishing of the apple industry in the Northeast is choice of cultivar for planting and sale. It is clear that the strength of the apple industry in this region will come increasingly from its ability to grow and sell apples for local retail markets. Because apples are a perennial crop with high initial cost of crop establishment, choice of cultivars to be planted charts the course of future marketability and farm viability for years to come. Evaluation of new cultivars for their quality, yield, and susceptibility to key pests was a principal aim of this project.
More specifically, this was a 3-year study of the influence of orchard architecture (specifically the nature of cultivar composition of perimeter-row apple trees and the nature of the border area habitat) on bio-based approaches to managing the 4 key apple pests. The primary objective was to reduce pesticide reliance in regional apple production through refinement of biologically-based management of these pests. The secondary objective was to enhance sustainability of northeastern apple production through evaluation of new cultivars. For both goals, the project proposes to improve our understanding of the orchard and surrounding ecosystem, and to use this understanding to improve apple orchard sustainability.
- 1. Development of baits and/or odors to trap plum curculio.
2. Development of a monitoring system using these traps.
3. Development of methods to use traps directly or indirectly in curculio management.
4. Development of bait to enhance pesticide-treated spheres to capture apple maggot fly.
5. Development of trap placement methods to minimize labor and optimize capture using treated spheres.
6. Release of mite predators into commercial test areas for management of red mites.
7. Red mite managed by mite predators as determined by periodic monitoring.
8. Determination of source and timing of initial inoculum for flyspeck disease.
9. Determination of key border and topographic factors contributing to flyspeck devleopment.
10. Development of a model to identify blocks at high-risk and low-risk of flyspeck.
11. Development of fungicide treatments to blocks and/or borders based on risk evaluation.
12. Determination of susceptibility of new apple cultivars to key pests through periodic monitoring over 3 years.
13. Determination of horticultural suitability of new apple cultivars through annual evaluation in each of 3 years.
For each of the three years, the study was conducted in 4 plots of apple trees in each of 12 commercial orchards (48 plots in all). Each plot measured 30-45 meters in perimeter-row length and ran 7 rows deep. In 6 of the 12 orchards, perimeter rows were comprised of the cultivars Gala, Jonagold or Fuji. Perimeter-row trees in the other 6 orchards were comprised of McIntosh or Empire cultivars. Habitat adjacent to perimeter rows consisted of woods, hedgerows or open field.
For plum curculios (PCs) immigrating from overwintering sites in border area habitats, during year one, three types of traps were tested: a)wire-mesh circle traps wrapped around trunks of perimeter-row trees, b) trunk-mimicking pyramid traps, and c) branch-mimicking cylinder traps. Three types of odor bait were tested in each type of trap: benzaldehyde+grandosoic acid (GA), limonene+GA or ethyl isovalerate+GA.
During the second year, sticky clear-plexiglass panel traps baited with plus grandisoic acid placed in orchard border areas (designed to capture PCs immigrating by flight) were tested against similarly-baited and similarly-placed black pyramid traps (designed to capture PCs immigrating by crawling) and similarly-baited wire mesh circle traps wrapped around trunks of perimeter-row apple trees (designed to intercept PCs crawling up tree trunks). In addition, a new “trap tree” approach, was introduced in year 2 which involved baiting branches of one perimeter-row tree per plot with benzaldehyde plus grandisoic acid. The significant aggregation (15-fold) of fresh ovipositional PC injury on trap trees was designed to facilitate monitoring of the seasonal course of PC injury to apples and to provide a new approach for determining need and timing of insecticide applications against PC. The addition of attractive odor to a trap tree resulted in significant aggregation (15-fold) of fresh ovipositional PC injury to fruit on trap trees thus facilitating monitoring of the seasonal course of PC injury to apples in a way that would allow growers to determine need and timing of insecticide applications against PC.
During the last year, a trap tree baited with benzaldehyde plus grandisoic acid was established as the central tree of the perimeter row of each of the 3 plots. Each plot was arbitrarily assigned a threshold of either 1, 2, or 4% freshly injured fruit on the trap tree. Each trap tree was sampled for freshly injured fruit 3 times per week.(M, W, F) beginning 7 days after a petal fall spray of insecticide to the entire plot. An entire plot insecticide application was made at petal fall to control PCs that had immigrated into interior rows before petal fall, but thereafter, insecticide against PC was applied only to perimeter and second rows and only when the proportion of trap-tree sampled fruit showing fresh injury had reached the pre-established threshold of 1, 2, or 4% for that plot.
For apple maggot flies (AMF) immigrating from overwintering sites in border area habitats, in years one and two, sticky red sphere traps were baited with a five-component blend of attractive synthetic fruit odor and placed 10 meters apart on perimeter-row apple trees and compared with similar traps baited with a single component of synthetic fruit odor (butyl hexanoate) placed in similar positions. Trap captures and damage were related to border structure and composition and apple cultivar composition in the blocks.
In year three, distances between spheres (range 5-15 meters) on perimeter trees were based on a newly-developed formula that incorporated tree size, extent of pruning, tree cultivar and nature of adjacent habitat as distance-determining factors. Performance was assessed on the basis of captures of AMF on unbaited monitoring spheres at interiors of plots and percent fruit injured by AMF.
For mites, which can be controlled biologically by predators, populations of both predator mites (Typhlodromus pyri, TP and Amblyseius fallacis, AF) and pest mites (European red mite, ERM) were counted in all blocks, and related to border structure and apple cultivars.
For flyspeck (FS), dispersed by wind from overwintering sites in border area habitats, during year one, the amount of overwintering FS on the alternate hosts in orchard borders was sampled by sampling thyriothecia, the “specks”. The proximity of these borders to apples was measured. Bi-monthly sampling extending up to 100 meters from borders into blocks of apples evaluated the impact of borders on flyspeck on fruit. The environmentally-benign fungicide trifloxystrobin (Flint) was evaluated as an alternative to standard captan applications.
In the second year, inoculum density and measurements on orchard border parameters were used to predict risk according to a previously developed empirical model. A system for evaluating border density, and to compare number and size of infected borders using a common metric was developed and used on the test blocks. Fewer applications of fungicide were recommended for third-level IPM blocks where risk was relatively low as compared to the applications that would be applied in blocks with higher risk estimates.
In the final year, we again surveyed blocks for FS risk factors, and evaluated overall block risk for FS. Fungicide recommendations were again adjusted to fit risk level, with low-risk blocks receiving relatively fewer applications. At the same time, conidial migration into the blocks was monitored using spore traps, and compared with FS incidence data taken during the season. Weather data were also taken in each block, and compared with spore capture and FS incidence.
As part of a study that evaluated the disease susceptibility of new cultivars, five replicates of twenty-one apple cultivars were evaluated each year in early summer for disease symptoms on leaves. Six terminals on each tree were examined for symptoms of four diseases: scab, cedar apple rust, frog-eye leaf spot, and powdery mildew. At harvest all fruit were counted and examined for symptoms of scab, flyspeck, sooty blotch, cedar apple rust, and bitter rot. The following horticultural characteristics were also evaluated: bloom, fruit set, yield, fruit size, fruit quality, and tree growth.
Our planned outcomes were primarily in terms of developing appropriate methods and technology to allow growers to decrease use of pesticides in apple orchards, while educating them and ourselves about the role played by the plants along orchard borders in apple pest management. This has set the stage for what we hope will be wide adoption of these new methods over the next few years. Towards that end, we have delivered talks and written articles in grower venues outlined below. These include annual New England apple meetings, as well as demonstrations in growers’ orchards during twilight meetings. The New England apple industry produces apples valued at approximately $125 million on approximately 20,000 acres.
This project has developed exciting new pest management methods for apple growers. For plum curculio, rather than applying two to five whole-orchard insecticides, a single application at petal fall can be followed by perimeter tree applications directed by sampling an odor-baited trap tree. The odor bait and trap-tree approach were developed in this project. For apple maggot, a new approach to odor-baiting pesticide spheres and a method for determining trap density based on cultivar composition and border distance eliminated the need for pesticide sprays, and reduced the number of traps required by 37%. For flyspeck disease, a method to determine disease pressure based on orchard border characteristics and flyspeck inoculum density reduced the number of fungicide sprays needed by 50% in low-pressure blocks. Within the low-pesticide blocks of the experiment, predator mites introduced at the outset provided excellent suppression of pest mites throughout the experiment.
Since the conclusion of the project, commercial development of the maggot trap has been set up, and recommendations for use of all methods have been incorporated into print and on-line publications.
Newsletters & periodicals for all years of grant:
Healthy Fruit – approx. 25 issues annually – circulation of 175 via surface mail and 125 via email – also web-published at www.umass.edu/fruitadvisor.
Fruit Notes of New England – approx. 4 issues annually– circulation of 400 via surface mail – also web-published at www.umass.edu/fruitadvisor.
Publications, events, and presentations during 2000 and 2001:
•Leskey, T.C. and R.J. Prokopy. 2001. Adult plum curculio attraction to fruit and conspecific odors. Annals of Entomological Society of America 94:275-288.
•Leskey, T.C., R.J. Prokopy, S.E. Wright, P.L. Phelan and L.W. Haynes. 2001. Evaluation of individual components of plum odor as potential attractants for adult plum curculios. Journal of Chemical Ecology 27:1-17.
•Opp, S.B. and R.J. Prokopy. 2000. Multiple mating and reproductive success of male and female apple maggot flies, Rhagoletis pomonella. Journal of Insect Behavior 13:901-914.
•Prokopy, R.J., B.W. Chandler, T.C. Leskey and S.E. Wright. 2000. Comparison of traps for monitoring plum curculio adults in apple orchards. Journal of Entomological Science 35:411-420.
•Prokopy, R.J., P.L. Phelan, S.E. Wright, A.J. Minalga, R. Barger and T.C. Leskey. 2001. Compounds from host fruit odor attractive to plum curculio adults. Journal of Entomological Science 36:122-134.
•Prokopy, R.J. and B.D. Roitberg. 2001. Joining and avoidance behavior in non-social insects. Annual Review of Entomology 46:631-665.
•Prokopy, R.J., S.E. Wright, J.L. Black, X.P. Hu and M.R. McGuire. 2000. Attracticidal spheres for controlling apple maggot flies: commercial orchard trials. Entomologia Experimentalis Applicata 97:293-299.
•Prokopy, R.J., S.E. Wright, J.L. Black and J. Rull. 2001. Size of orchard trees as a factor affecting behavioral control of apple maggot flies by traps. Journal of Applied Entomology 125:371-375.
•Rull, J. and R.J. Prokopy. 2001. Effect of apple orchard structure on interception of Rhagoletis pomonella flies by odor-baited traps. Canadian Entomologist 133:355-363.
•Clements, J. and D. Greene. 2000. Zestar! – A Paulared Alternative for the Northeast? Fruit Notes of New England 65:17-19.
•Clements, J., D. Greene, and W. Cowgill. 2001. Zestar – A New Apple for the Northeast. Rutgers Cooperative Extension Plant & Pest Advisory Newsletter, Fruit Edition 6(22):6-7.
•Cowgill, W, and J. Clements. 2000. ‘Orchard Production Beyond 2000.’ American Fruit Grower November:12-16.
•Greene, D. W., S. A. Weis, and J. Krupa. 2001. Promising new apple cultivars for New England. Proc. New England Fruit Meetings 106:21-24.
•Piñero, J., K. Bednaz, A. Ross, and R. Prokopy. 2000. Spatial distribution of plum curculio egglaying in apple trees. Fruit Notes of New England 65:36-41.
•Piñero, J., R. Prokopy and S. Wright. 2000. Using odor-baited traps to capture immigrating plum curculios. 2000. Fruit Notes of New England 65:42-44.
•Prokopy, R. 2000. Can Surround™ be applied successfully with a back-pack sprayer to control plum curculio? Fruit Notes of New England 65:28-29.
•Prokopy, R., B. Chandler, S. Wright and J. Piñero. 2000. Evaluation of baited and unbaited traps for monitoring plum curculios. Fruit Notes of New England 65:32-35.
•Prokopy, R., S. Wright, J. Black, J. Nyrop, K. Wentworth and C. Hering. 2000. Establishment and spread of released Typhlodromus pyri predator mites in apple orchard blocks of different tree size: 1999 and final results. Fruit Notes of New England 65:6-16.
•Prokopy, R., S. Wright, R. Fleury, S. McIntire, K. Hanley, L. Phelan and R. Barger. 2000. Evaluation of host-odor compounds for attractiveness to plum curculio adults: 2000 results. Fruit Notes of New England 65:30-31.
•Wright, S., B. Chandler, R. Fleury and R. Prokopy. 2000. Pursuit of effective pesticide-treated spheres for controlling apple maggot. Fruit Notes of New England 65:45-49.
•Wright, S., R. Fleury, R. Mittenthal and R. Prokopy. 2000. Small-plot trials of Surround™ and Actara™ for control of common insect pests of apples. Fruit Notes of New England 65:22-27.
For web access to UMASS Fruit Team publications such as Healthy Fruit, Fruit Notes of NewEngland, fact sheets, and meeting notices go to: www.umass.edu/fruitadvisor.
•Clements, J. January 2001. Video: Role of Computer Technology in a Commercial Orchard.’ UMass Fruit Advisor, www.umass.edu/fruitadvisor/clements
•Clements, J. March 2001. ‘Sprayer Calibration Worksheet.’ UMass Fruit Advisor, www.umass.edu/fruitadvisor/clements
Fruit Advisory Committee: Annual meeting on April 10, 2001, 25 attending (other than UMASS personnel); additional meeting in Jan. 2001 of the fruit grower members, 15 attending; consulted with members in October, 2001 by distributing plans/ ideas for future work and soliciting comments, Oct. 2001.
Fruit Advisory Committee members include the following:
• Tree Fruit Growers: Bill Broderick, Frank Carlson, Dave Chandler, Tom Clark, Bill Hamilton, Gene Kosinski, Tony Lincoln, Ken Nicewicz, Wayne Rice, Rob Russell, Mo Tougas, and Bob Tuttle.
• Private Consultants: Kathleen Leahy (Polaris Orchard Management), Glen Morin, Robin Spitko (New England Fruit Consultants).
• Environmental Consultants: Alexandra Dawson (environmental lawyer/activist), Julia Freedgood (American Farmland Trust), William Lockeretz (Tufts University School of Public Health).
• Supermarket Produce Manager: Matt Boulanger.
• Orchard Equipment Manager: Russ French.
• Representative of MDFA: Bob Rondeau.
Field days, workshops, conferences:
Date , Title, Location, Attendance
10/13, Sustainable Orcharding, Belchertown, MA, 14
1/10-11, New England Fruit Meetings, Sturbridge, MA, 813
3/22, Orchard Sprayer Calibration, Belchertown, MA, 26
4/10, April Twilight Meeting, New Salem, MA, 53
4/11, April Twilight Meeting, Berlin, MA, 56
4/12, April Twilight Meeting, Johnston, RI, 35
5/8, May Twilight Meeting, Dummerston, VT, 35
5/9, May Twilight Meeting, Phillipston, MA, 42
5/10, May Twilight Meeting, Wrentham, MA, 54
6/13, June Twilight Meeting, Westfield, MA, 35
6/14, June Twilight Meeting, Burrillville, RI, 38
6/15, High-density Study Group Meeting, Hollis, NH, 15
6/19, June Twilight Meeting, Pepperell, MA, 45
7/25, Summer Meeting, Mass. Fruit Growers, Sterling, MA, 82
Presentations for Grower Audiences:
Date, Title, Location, Attend.
10/13, Sustainable Orcharding, Belchertown, MA, 14
1/10, Web-based Orcharding Tools, Sturbridge, MA, 382
1/10, Survival in the 21st Century, Sturbridge, MA, 431
1/10, NE-183, Evaluation of Cultivars Poster, Sturbridge, MA, 813
1/22, Survival in the 21st Centruy, Broadway, NJ, 75
2/15, Management of Tree-fruit Plants, Amherst, MA, 85
2/20, Kaolin Clay for Pest Control, Barre, MA, 25
2/20, Tactics for Managing Apple Maggot, Augusta, ME, 70
2/20, Tactics for Managing Plum Curculio, Augusta, ME,
4/10, Early-season Insects, New Salem, MA, 53
4/10, Tree-fruit Diseases, New Salem, MA, 53
4/11, Early-season Insects, Berlin, MA, 56
4/11, Tree-fruit Diseases, Berlin, MA, 56
4/11, Horticultural Topics, Berlin, MA, 56
4/12, Early-season Insects, Johnston, RI, 35
4/12, Horticultural Topics, Johnston, RI, 35
5/8, Mid-season Insects, Dummerston, VT, 35
5/8, Horticultural Topics, Dummerston, VT, 35
5/9, Mid-season Insects, Phillipston, MA, 42
5/9, Horticultural Topics, Phillipston, MA, 42
5/10, Mid-season Insects, Wrenthem, MA, 54
5/10, Horticultural Topics, Wrenthem, MA, 54
6/13, Summer Orchard Management, Westfield, MA, 35
6/13, Summer Insects, Westfield, MA, 35
6/13, Summer Diseases, Westfield, MA, 35
6/14, Summer Orchard Management, Burrillville, RI, 38
6/14, Summer Insects, Burrillville, RI, 38
6/14, Summer Diseases, Burrillville, RI, 38
6/19, Summer Orchard Management, Pepperell, MA, 45
6/19, Summer Insects, Pepperell, MA, 45
6/19, Summer Diseases, Pepperell, MA, 45
6/21, Orchard insects, Amesbury, MA, 21
Presentations for Scientific Audiences:
Date, Title, Location, Attend.
10/25, Evaluating the Risk of Flyspeck, Burlington, VT, 25
12/7, Chemical Ecology of Plum Curculio, Montreal, Canada, 68
Publications, events, and presentations during 2002:
• Clements, J. 2002. Photo gallery of apple cultivars in the NE-183 1999 plantings. Web-published at: http://umass.edu/fruitadvisor/clements/research/ne183/1999/index.htm.
• Clements, J. 2002. Photo gallery of apple cultivars in the NE-183 1995 planting. Web-published at: http://umass.edu/fruitadvisor/clements/research/ne183/index.htm.
• Greene, D. 2002. Descriptions of the cultivars in the NE-183 second planting. Web-published at: http://firstname.lastname@example.org.
• Hoffman, S., R. Mittenthal, B. Chandler, G. Lafleur, S. Wright, M. Becker, S. Dynok, and R. Prokopy, 2002. Influence of odor bait, cultivar type, and adjacent habitat on performance of perimeter traps for controlling apple maggot flies. Fruit Notes of New England 66(2):20-24.
• Prokopy, R, B. Chandler, and J. Piñero, 2002. Commercial orchard evaluation of traps for monitoring plum curculio: 2001 results. Fruit Notes of New England 67(1):17-22.
• Tuttle, A., C. Bergweiler, J. Hall, L. Reisner, S. Christle, W. Autio, and D. Cooley, 2002. Development of a model for predicting flyspeck risks in blocks of apple trees. Fruit Notes of New England 67(1):5-8.
The following 2 articles report on studies supported by a previous (1997-1999) SARE grant:
• Wright, S., B. Zhao, and R. Prokopy, 2002. Species composition of third-generation leafminers in Massachusetts apple orchards: 1997-1999. Fruit Notes of New England 67(3): 10-13.
• Zhao, B., S. Wright, and R. Prokopy. 2002. Population dynamics of leafminers and their parasitoids in Massachusetts apple orchards. 1999 studies. Fruit Notes of New England 67(3): 14-17.
Fruit Advisory Committee: Annual meeting on March 25, 2002, 25 attending (other than UMASS personnel). New member: representative of MA DFA Pesticide Bureau: Steven Antunes-Kenyon.
Field days (twilight meetings), workshops, and conferences:
Date, Title, Location, No.
1/9-10, New England Fruit Meetings, Sturbridge, MA, 732
3/14, Pruning tree-fruit plants, Dighton, MA, 20
4/9, April Twilight Meeting 1, Belchertown, MA, 35
4/10, April Twilight Meeting 2, Peabody, MA, 46
4/11, April Twilight Meeting 3, Little Compton, RI, 36
5/14, May Twilight Meeting 1, Tyngsborough, MA, 42
5/15, May Twilight Meeting 2, Westfield, MA, 25
5/16, May Twilight Meeting 3, N. Scituate, RI, 40
6/11, June Twilight Meeting 1, Ashfield, MA, 35
6/12, June Twilight Meeting 2, Lunenburg, MA, 35
6/13, June Twilight Meeting 3, Westport, MA, 41
7/10, Summer Meeting, Mass. Fruit Growers, Belchertown, MA, 95
11/8-9, NE-183 Annual Meeting, Egg Harbor, WI, 28
Date, Title, Location, No.
11/01, Apple Variety Showcase, UMASS Hort. Center, Belchertown, MA, 20
11/01, Red, round, and ripe, Univ. of Kentucky, 56
1/02, New developments in trapping plum curculio, New England Fruit Meetings, 180
6/02, Trap trees for monitoring plum curculio, NH Fruit Growers Mtg., 24
10/23/02, Orchard borders and flyspeck disease, New Eng., NY, & Can. Frt. Pest Mgmt. Wkshp., 21
Publications, events, and presentations during 2003:
• Autio, W.R., J. Clements, J. Krupa, D. Greene and D. Cooley. 2003. Annual Report to NC-140. Web-published at http://www.umass.edu/fruitadvisor/research/Mass-NC-140-2003.pdf (root cultivar evaluations)
• Greene, D. W and S. A. Weis. 2003. Apple varieties with a future. Compact Fruit Tree 36(2):55-56.
• Greene, D.W and S.A. Weis. 2003. Apple varieties with a future. Compact Fruit Tree 36(2):55-56
• Greene, D.W., J.M. Clements, D.R. Cooley, W.R. Autio and A.F. Tuttle. 2003. Annual Report to NE 183: Disease and horticultural evaluations of the 1999 NE183 plantings. Web-published at http://www.fruitadvisor.umass.edu/research/Mass-NE-183-2003.pdf.
• Prokopy, R.J., B.Chandler, S.Dynok, E.Gray, M.Harp, and J.Piñero. 2003. Comparison of traps and trap trees for monitoring plum curculios: 2002 results. Fruit Notes 68(1): 5-10
• Prokopy, R.J., B.W. Chandler, S.A. Dynok and J.C. Piñero. 2003. Odor-baited trap trees: a new approach to monitoring plum curculio. Journal of Economic Entomology 96:826-834
• Prokopy, R.J., R.E. Mittenthal and S.E. Wright. 2003. Evaluation of trap deployment patterns for behavioral control of apple maggot flies. Journal of Applied Entomology 127: 276-281
Fruit Advisory Committee: Annual meeting on March 24, 2003, 21 attending (other than UMASS personnel).
Field days (twilight meetings), workshops, and conferences in 2003 in MA:
Date, Title, Location, No. Attending
October 11, Sustainable Orcharding, Belchertown, 15
January 8-9, New England Fruit Meetings, Sturbridge, 355
April 1, Managing Fruit Trees in the Landscape, Belchertown, 40
April 15, April Twilight Meeting, Wilbraham, 35
April 16 , April Twilight Meeting, Harvard, 70
April 17, April Twilight Meeting, Dighton, 30
May 13, May Twilight Meeting, Belchertown, 45
May 14, May Twilight Meeting, Northborough, 60
May 15, May Twilight Meeting, Essex, 45
May 15, Essex County Fruit Growers, Methuen, 15
June 10, June Twilight Meeting, Richmond, 25
June 11, June Twilight Meeting, Stow, 46
June 12, June Twilight Meeting, Westport, 33
July 24, Massachusetts Fruit Growers’ Summer Meeting, Shelburne, 145
October 23, Mass. Assoc. of Roadside Stands Twilight Meeting, Amesbury, 10
Presentations of SARE-sponsored research outside MA in 2003:
• Prokopy, Ronald. Minnesota Fruit Growers, January 03: One talk on plum curculio research and one talk on apple maggot fly research
• Prokopy, Ronald. Rutgers University, April 03: A seminar on plum curculio research
• Prokopy, Ronald. New England Fruit Meeting, December 03, Manchester, NH: A talk on latest developments in plum curculio and apple maggot fly research
• Clements, Jon. Annual NE183 Meeting, Kentville, Nova Scotia, November, 03: Disease evaluations for new cultivars
Publications in 2004:
Prokopy, R.J., I. Jácome, E. Gray, G. Trujillo, M. Ricci, and J.C. Piñero. 2004. Using odor-baited traps as sentinels to monitor plum curculio (Coleoptera: Curculionidae) in apple orchards. J. Econ. Entomol. 97(2): 511-517.
Prokopy, R.J., I. Jácome, and E. Bigurra. 2004. An index for assigning distances between odor-baited spheres on perimeter trees of orchards for control of apple maggot flies. Entomologia Experimentalis Applicata (accepted for publication)
Additional articles will appear in 2004-2005 issues of Fruit Notes of New England
Impacts of Results/Outcomes
Excellent progress was made in the advancement of bio-based management of the 4 key pests. For plum curculio, in year one, a baited circle trap was especially effective in capturing the weevils. Three cultivars, Gala, Jonagold, and Fuji were more susceptible to PC than Empire or MacIntosh (years one and two). In year two, none of the trap types tested exhibited amounts of captures that correlated significantly with either weekly or season-long amounts of fresh ovipositional injury to fruit by adults. Hence, none appears to offer high promise or a tool for effectively monitoring the seasonal course of PC injury to apples. However, a new odor-baited “trap tree” approach was especially effective in monitoring PCs in the second year, and in the last year, this approach for localizing and monitoring fresh injury to fruit caused by plum curculio led to a 74% reduction in insecticide use against this key pest in plots where spray applications were driven by a pre-set threshold of one freshly injured fruit out of 50 fruit sampled on a trap tree. The trap tree approach performed well across various apple cultivars and border habitats. Our findings lead us to conclude that after a whole-orchard insecticide application against PC at petal fall, subsequent applications can be confined to peripheral-row trees and be driven by a provisional threshold of 1 freshly injured fruit out of 50 fruit sampled on a perimeter-row odor-baited trap tree.
For apple maggot, during years one and two, sticky red spheres, when baited with a blend of five components of synthetic fruit odor were more effective for trapping-out AMF than spheres baited with a single component, except in cultivars such as Gala, Jonagold, or Fuji, which were particularly susceptible to AMF (years one and two). In the second year, the sticky red spheres with the five-component bait were again more effective for trapping-out AMF than spheres baited with a single component, and were equal to grower sprays in controlling AMF. During the last year, a new approach to determining distance between odor-baited sphere traps that incorporated type of apple cultivar and nature of border habitat as distance-determining factors led to a 100% reduction in insecticide use against apple maggot and a 37% reduction in number of traps needed to achieve direct control.
For flyspeck, during year one the amount of overwintering FS on the alternate hosts in orchard borders in June, the proximity of these infected borders to apples, and the number and size of infected borders around a block of apples were key elements in determining damage at harvest. Blocks that were adjacent to borders that had little or no FS in June, or had only grassy or distant borders, had little or no FS at harvest, regardless of summer fungicide use, while borders that had moderate or high levels of FS in their borders and/or borders that were close had higher FS incidence. In year two, FS incidence was very low in June on alternate host-plants in the orchard border areas and in September on apples in all but three blocks, due to continuing drought conditions, emphasizing the importance of weather in a given year as well as pre-existing risk factors. Flyspeck symptoms were greatest on apples that bordered on hedgerows and woods. Reduced fungicides in low-risk blocks worked well but this was aided by the dry conditions. Weather in year three was dramatically wetter. At harvest, there were an average of 84% infected fruit in unsprayed control plots, 11% infected fruit in high-risk blocks that received 3 or 4 summer sprays, and 5% infected fruit in low-risk blocks that received 2 summer fungicide sprays. Summer fungicide use was reduced by 57% in low-to-moderate risk plots as compared to high-risk plots, indicating that block-specific fungicide applications can be effective and used to reduce fungicides targeting FS. In all years, trifloxystrobin performed as well or better than the captan applications. Applications to border plants caused a brief (ca. 1 week) suppression in conidial production as indicated by spore trapping, but had no significant effect on disease incidence.
Cultivar composition did not have an effect on FS disease severity, although lateness of ripening did. Fuji was the last cultivar to be harvested and had the most FS.
Beneficial mites were established in all advanced IPM blocks during the first two years of the study. Typhlodromus pyri mite predators released in 2000 continued to provide excellent suppression of pest mites in most orchards in 2003, regardless of tree cultivar and nature of border habitat.
Milestones affecting more than 1 pest:
Apples bordered by woods and hedgerows received more AMF and FS injury than blocks bordered by open grassy areas, while apples bordered by woods received more PC injury than apples bordered by hedgerows or open areas.
Pesticide reductions were obtained in all advanced IPM blocks for AMF and for mites as compared to 1st-level IPM grower-sprayed blocks. Advances in PC trap design, placement, and baiting indicate potential future pesticide reduction.
Growers planting new blocks may achieve more pesticide reduction by placing susceptible cultivars on perimeter rows and concentrating immigrant PC and AMF there.
Evaluation of new cultivars:
Differences in bloom, fruit set, fruit quality, and disease susceptibility (or resistance) exist, but these are young trees, and part of this can be attributed to differences in precocity and fruit set. A more accurate picture of tree performance and disease susceptibility/resistance will develop when trees fruit for several seasons and biennial cycles manifest themselves. However, even now we are getting a sense of which will be the most precocious, high yielding, best tasting, and most disease-resistant cultivars. As it becomes possible to identify promising cultivars, we will make preliminary recommendations at grower meetings and through UMASS extension publications for planting these cultivars in New England. One cultivar, Scarlet O’Hara (Coop 25), from the 1999 planting, seems especially good. Goldrush and Pristine are stand-outs in the 1995 planting. These are all scab-resistant. Goldrush also gets high scores for maintaining fruit quality in storage. Among the non-resistant new cultivars, Cameo and Honeycrisp (from the 1995 planting) are showing consistent promise.
One criticism of advanced apple IPM in recent years is that it is too expensive to do relative to the benefits growers realize. In particular, advanced IPM has become increasingly labor-intensive, and mistakes increasingly expensive in terms of damaged fruit. In an apple market with vanishing profit margins, extra costs of any sort are difficult to tolerate. In the long term, increased prices for ecologically produced fruit may help counter this trend. However, in the context of this project, we looked at methods that might decrease costs of IPM.
The AMF trap is a case in point. The original, unbaited sticky sphere without pesticide needed to be placed in large numbers around an orchard block, and cleaned every two to three weeks: an arduous, expensive process. The solution developed in this project was refinement of the baited, pesticide-treated sphere, in conjunction with a method to calculate how densely spheres need to be placed around orchard borders. Decreasing the number of spheres needed by 37%, eliminating the need to clean spheres, and eliminating the need for any maggot sprays gives growers much more economic incentive to use this more ecologically sound approach. Similarly, the PC approach limits scouting to a few trap trees on the orchard border, and after an initial whole-orchard application limits sprays to the borders. This saves money over several whole orchard applications, the previous norm. Fungicide applications for flyspeck are generally based on calendar considerations or maggot sprays. With AMF spheres, maggot sprays are not necessary, and the practice of “adding some fungicide to the maggot spray just to be safe” can be eliminated. Growers still need to use some fungicide, but based on methods developed in this project, can spray block by block based on disease risk in those blocks. These methods both save applications and decrease summer disease incidence. The practice of introducing predatory TP mites has held up over the long-term, and is far less expensive than using miticides. As the new generation of cultivars graduates from the evaluation process, and a few promising disease-resistant ones, like Goldrush, Scarlet O’Hara and Pristine become commercially available, growers will have the opportunity to further reduce their fungicide inputs.
None of the new methods developed in this project resulted in increased pest damage, and all reduced the need to make pesticide applications. This should provide growers with good reason to adopt these methods in the near future.
Areas needing additional study
In government and academic reports on agricultural research, we tend to limit our recommendations for the future to those specific pieces of work that are the next steps in a particular area of crop production. It’s about the work, not the people. But in looking at the future of the type of research and education projects funded by SARE, it is critically important to note the passing of Ronald Prokopy, who for so many years led apple IPM efforts in the region, and indeed in the world. Both producers and colleagues in the northeastern apple community feel the loss. Just as important, in the context of this report, his loss clearly points out a fundamental challenge to the future of applied agricultural research and education.
Today, universities are unlikely to replace people with Prokopy’s particular mix of applied and basic research skills, both because the opportunities for funding such work are shrinking, and because there are very few students trained to do applied work. In addition to the loss of a scientist of Prokopy’s individual abilities, the loss of his position in conjunction with the loss of other positions in New England puts us, the agricultural land grant community, dangerously close to the minimum number of scientists necessary to do research and education in sustainable agriculture on fruit and other crops in the region. The work cannot get done without the people to do it. If we could make only one recommendation for the future, it would be that the country renew its commitment to and support for public research and education, and particularly in sustainable agriculture, through the land grant universities.
The need for further research and education in sustainable agriculture in general and in sustainable apple production specifically remains great. For example, we have developed exciting new methods to reduce pesticides used to control plum curculio, apple maggot, red mites and flyspeck. While they have worked in small-scale tests, questions remain about how they will perform at larger scales and over several years. Our experience in IPM tells us that the apple agroecosystem is dynamic, and will present both new challenges and opportunities any time we make a change in the way we grow the fruit.
Apple scab remains a major challenge for apple growers in New England and in many parts of the world. The three-pronged pressures from resistance to existing fungicides, the expense of new fungicides and the public’s desire for food grown with fewer pesticides make it important that new scab-management methods be developed. This can probably best be accomplished by adapting cultural methods and predictive models to systems that modify orchard architecture and cultivars, both scab-resistant and non-resistant.
Our new understanding of flyspeck and related summer diseases can be applied to cultural methods, such as destroying initial inoculum or modifying orchard micro-climates, so as to minimize need for fungicides. A model used to time summer fungicide applications needs further development if it is to be used commercially. At the same time, bio-rational materials, such as calcium salts already used to improve apple quality, should be further studied as alternatives to more toxic fungicides.
The pesticide-treated maggot spheres need to be further developed and commercialized. Questions remain as to how and when to best deploy these traps whole orchards, and whether concurrent border or cultivar modifications need to be made for economically viable use.
We have made excellent progress in trapping plum curculio in order to time insecticide applications. Further progress may be made in using these methods to draw invading curculios to a trap tree, and treating only that tree. This will be dependent on identifying high-risk orchard borders and insuring that curculio is eliminated from orchard interiors.
Future work on sustainable apple production will focus on cultivar selection and horticultural methods within the orchard and reach into the plants and ecology immediately bordering them. At the same time, to remain competitive, growers in this region will need to codify and use standards of ecologically sound fruit production. The public demands it, and growers and governments in other parts of the world are providing it. To remain economically viable, apple orchards in the northeastern U.S. will need to do the same.