Progress 07/15/08 to 07/14/11
Outputs
OUTPUTS: OUTPUTS. The objectives of this project were tailored to optimize performance and commercial values of attracticidal sphere traps for direct control of apple maggot fly (AMF) in apple orchards. Given success in optimization of formulation, structure, and deployment strategy for these traps, we anticipated yield of a trap-based control system for AMF that can replace broadcast insecticide sprays in commercial orchards with no loss in pest control and little increase in management costs. In Year 1 of this project, we conducted a series of laboratory experiments at USDA-ARS-Appalachian Fruit Research Station (Kearneysville, WV) and New York State Ag Experiment Station (Geneva, NY) aimed at determining synergistic combinations of feeding stimulant, feeding attractant and toxicant. Targeted trap-output parameters were defined in AMF feeding trials with various trap formulations and rainfall exposure periods; contribution of each variable to overall residual lethality was then validated in controlled laboratory studies of synergism. Performance of feeding attractant was evaluated both for contribution to trap lethality and improvement of trap finding by foraging AMF. In field studies in Year 1, we evaluated the adequacy of the prototype trap's visual form, assessing the impact of variation from known optimal shape and size. In Year 1 and Year 2 of this project, we evaluated the protective capacity of attracticidal sphere traps for control of AMF using caged-tree studies. These studies were designed to translate findings of trap-lethality and trap-finding experiments to a controlled field environment, allowing assessment of trap-based protection of a known density of fruit exposed to a known density of AMF. Combined results of Year 1 allowed us to design a performance-based trap deployment strategy combining experimental findings of appropriate toxicant rate, feeding attractant rate, trap form, and enhancement of trap attractiveness by use of volatile host-fruit odors. In Year 2 and Year 3 (project extension), this comprehensive approach for behavioral control of AMF was evaluated in 12 commercial orchards in New England and New York. The principal outcome of this project has been systematic refinement and broad-scale, on-farm demonstration of the potential for use of attracticidal sphere traps for control of AMF. Though not unilaterally successful in controlling AMF on commercial farms, further development of this approach has been generally embraced by commercial apple growers in the Northeast. Throughout the term of this project, growers, cooperators, and the tree fruit research and extension communities were kept abreast of outputs and outcomes through on-farm extension talks (2: Concord, NH and Hollis, NH), invited talks to regional grower groups (2: Winchester, VA and Boscawen, NH), and submitted talks to annual meetings of pertinent research and extension groups (3: Reno, NV; Burlington, VT; and Syracuse, NY). PARTICIPANTS: Project Director: Tracy Leskey, Research Entomologist, USDA-ARS Project Investigators: Starker Wright, Support Entomologist, USDA-ARS; Tom Tworkoski, Plant Physiologist, USDA-ARS; W. Harvey Reissig, Professor of Entomology, Cornell University; Peter Jentsch, Extension Associate, Cornell University Cooperating Commercial Growers: Chuck Souther, Concord, NH; Rick Leadbeater, Contoocook, NH; Steve Wood, Lebanon, NH; Ezekiel Goodband, Dummerston, VT; Aaron Clark, Ashfield, MA Partner Organizations and Collaborators: Kathleen Leahy, Polaris Orchard Management; Joe Sincuk, University of Massachusetts Horticultural Research Center; Arthur Tuttle, University of Massachusetts Tree Fruit IPM Program; Dan Cooley, University of Massachusetts Department of Plant, Soil, and Insect Science; Jim Hansel, Great Lakes IPM TARGET AUDIENCES: Target Audience: commercial apple growers, tree fruit entomologists, Cooperative Extension Service agents in the USA and Canada. Extension and Outreach Efforts: grower-cooperator farm visits for deployment, maintenance, and assessments; on-farm grower meetings and presentations; and invited and submitted research and extension presentations. PROJECT MODIFICATIONS: In order to re-evaluate attracticidal sphere trap performance in commercial apple orchards, a one-year project extension was proposed and approved, extending the project termination date to 07/14/2011.
Impacts
Outcomes/Impacts. Under Obj 1, we evaluated combinations of toxicant rate (spinosad: 0.0, 0.1, and 0.5%) and feeding attractant (ammonium carbonate: 0.0, 5.0, and 10.0%) as dispersible constituents of attracticidal spheres. Greatest lethality was observed when AMF were exposed to treatments containing highest rate of toxicant; higher rate of feeding attractant contributed significantly to both lethality of traps and longevity of effects. In subsequent trials of lethality of controlled residues, we evaluated effects of 80 treatments: combinations of toxicant rate (0.0, 0.1. 1.0, 10.0, and 100.0 ppm); hygroscopic feeding attractant (0, 10, 100, and 1000 ppm); and feeding stimulant (0.0, 0.1, 1.0, and 10.0%). It was revealed that with controlled 3-component residues, factors contributing to lethality were toxicant rate and feeding stimulant rate; presence of higher rates of feeding attractant had no impact on lethality of residues. Combined results demonstrate that as a trap constituent, ammonium carbonate enhances release of sucrose and toxicant under trap exposure to environmental moisture, and may preserve the lethality of naturally formed toxicant residue on trap surfaces. Under Obj 2, trials revealed that as traps deviated from full round, response of foraging AMF declined. Deviation of 1, 2, and 4% from full-round resulted in reduction of captures by 12.4, 10.1, and 24.6%, indicating that caps should be manufactured to provide a visual stimulus which is as close to spherical as is possible. Inclusion of feeding attractant in sphere caps marginally increased capture of foraging AMF, but resulted in capture 2-3x more non-target Diptera, which may interfere with alightment of targeted AMF. Under Obj 3, trials revealed that inclusion of 5-component apple volatile increased response of AMF without regard to inclusion of food-based volatile constituents. In caged-tree trials, attracticidal spheres killed all released flies prior to oviposition in fruit distributed in the canopies of caged trees. However, little oviposition was recorded in caged trees without lethal traps (though AMF did survive), suggesting that the experimental design did not present a microclimate in which AMF were likely to express natural oviposition. From the findings of Objs 1-3, we selected a formulation and deployment strategy for demonstration in commercial orchards in the Northeast in Year 2 of this project. Trap formulation consisted of 10% ammonium carbonate and 0.5% (ai) spinosad; unfortunately, traps of this type failed to control the outbreak of AMF experienced in this growing season. The most likely mechanism of trap failure was premature release of feeding stimulant and toxicant under the exceptionally wet conditions in the Northeast during this growing season. Traps were reformulated with higher rate of toxicant (1.0%) and feeding attractant was removed to limit the rate of output of toxicant and feeding stimulant. In Year 3 of this project, field control was regained: oviposition injury was maintained at a rate below that considered commercially acceptable (1.0%), and injury in trap-protected plots did not differ from grower-managed control plots.
Publications
- Wright, S.E., D. Combs, W.H. Reissig, and T.C. Leskey. 2012. Effects of sucrose and ammonium carbonate on uptake and lethality of spinosad for apple maggot fly (Diptera: Tephritidae). In preparation.
- Wright, S.E., T.C. Leskey, I. Jacome, J.C. Pinero, and R.J. Prokopy. 2011. Integration of insecticidal, phagostimulatory, and visual elements of an attract-and-kill system for apple maggot fly (Diptera: Tephritidae). Journal of Economic Entomology (submitted).
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Progress 07/15/08 to 07/14/09
Outputs
OUTPUTS: The aim of this project is to enhance performance and commercial value of attracticidal spheres for behavioral control of apple maggot fly (AMF). The impact of inclusion of hygroscopic feeding attractants on lethality of attracticidal spheres has been evaluated. Under Obj. 1, Exp. 1, a laboratory trial which assessed residual lethality of varying concentrations of the toxicant spinosad (Entrust) combined with the feeding stimulant sucrose and the feeding attractant ammonium carbonate against AMF was completed. These results were used to generate the formulation used in subsequent experiments. For Obj. 1, Exp. 2. the collection of residue output of the visually integrated toxicant/stimulus release caps is being conducted. Toxicant-stimulant release caps are fitted to sphere trap bodies and exposed to rainfall at 2.5 cm intervals through ~50 cm of accumulated rainfall exposure. Runoff is being captured from representative exposure intervals and stored for analysis; after each rainfall exposure, traps are subjected to bioassay using adult AMF. Fly condition is assessed 4, 24, and 48 hours after exposure. In order to assess attractiveness of the visually integrated release cap attached to the trap sphere body, the visual tolerance of AMF to slight variation in sphere form was evaluated with caps of three sizes resulting in 1%, 2%, and 4% deviation from and compared with a full-round visual stimulus based on captures of wild adults in an unsprayed orchard. The impact integrated food-based attractants (Obj. 2, Exp. 2) incorporated into the release cap are being compared with control caps. Attractiveness is being assessed based on captures on a Tangletrap-treated sphere deployed in close proximity to spheres bearing caps with and without feeding attractants and mark-release-recapture studies (Obj. 3, Exp. 1) also are concurrently being conducted to determine if AMF preferentially select and accept tree canopies with spheres fitted with release caps bearing feeding attractants. In Obj. 3, Exp. 2, we are evaluating the protective capacity of attracticidal trap formulations based on release of AMF adults within caged enclosures, with each cage containing a single mature Gala apple tree and bearing 25 uninfested, insecticide-free Gala fruit suspended in the canopy. At the end of the exposure period, all fruit are removed from each of the canopies and stored at room temperature for subsequent damage assessments. In Obj. 3, Exp. 2, we are assessing the performance of commercial-orchard deployment of attracticidal spheres for control of AMF in commercial orchards in NY, VT, NH, and WV based on a perimeter deployment strategy, and in VA and NY based on a saturation deployment strategy. We have delivered extension programs at regional twilight meetings in NH and VA based on results to date to facilitate knowledge transfer and implementation by stakeholders (Obj. 4). PARTICIPANTS: Project Director: Tracy Leskey, Research Entomologist, USDA-ARS Appalachian Fruit Research Station, Kearneysville, WV. Project Investigators: Starker Wright, Support Entomologist, USDA-ARS Appalachian Fruit Research Station, Kearneysville, WV; Tom Tworkoski, Plant Physiologist, USDA-ARS Appalachian Fruit Research Station, Kearneysville, WV; Harvey Reissig, Professor of Entomology, Cornell University, Geneva, NY; Peter Jentsch, Extension Associate, Hudson Valley Laboratory, NY State Ag. Exp. Station, Highland, NY TARGET AUDIENCES: Commercial apple producers, tree fruit entomologists and Cooperative Extension Service agents in the USA and Canada PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results under Obj. 1, Exp 1 have revealed that residue containing 10-1000 ppm ammonium carbonate (feeding attractant), 1-10% sucrose (feeding stimulant) and 10-100 ppm spinosad (toxicant) will reliably result in 80-100 % mortality within 48h, respectively. Based on rainfall trials to date (Obj. 1, Exp. 3), caps exposed to 45+ cm of rainfall still maintain lethality of 85% or more, as long as the caps contain a high rate of hygroscopic feeding attractant. If the rate of this additive (ammonium carbonate) is reduced or eliminated, traps only maintain this level of lethality through ~25 cm of accumulated rainfall. Given a target of >85% lethality through 40 cm of rainfall, these bioassay results translated into field deployment of traps bearing 10% ammonium carbonate, 70% sucrose, and 0.5% (AI) spinosad. AMF are visual specialists, although results under Obj. 2, Exp. 1 revealed that spheres deviating from full round form by 1%, 2%, and 4% and compared with a full round stimulus resulted in overall captures that were not significantly different among treatments. Overall captures were reduced 12.4, 10.1 and 24.6%, for shape deviations of 1%, 2%, and 4%, respectively, indicating that release caps should be manufactured to provide a visual stimulus which is as close to full round as mechanically possible. Under Obj. 2, Exp.2, we have found that the inclusion of feeding attractants increases the attractiveness of spheres to non-target Diptera 2-3x compared with spheres lacking feeding attractants and may interfere with the ability of foraging AMF to alight on traps. However, based on Obj. 2, Exp. 2 and on Obj. 3, Exp. 1, the inclusion of the 5-component apple volatile lure appears to increase overall captures of AMF across treatments regardless of inclusion of close-range feeding attractants indicating that this fruit volatile lure reliably attracts AMF to tree canopies bearing this host-based stimulus. For Obj. 3, Exp. 2, the protective capacity of sphere traps correlates with the lethality rates found in Obj. 1, Exp. 3. In controlled cage studies, traps bearing hygroscopic feeding attractants provided the greatest level of fruit protection; the presence of fruit-volatile baits adjacent to traps had little impact on the close-range spatial protective capacity of the visual traps. Extension programs describing progress made in development of attracticidal spheres for AMF based on this have been delivered in NH in July 2008 (~80 stakeholders in attendance) and July 2009 (~50 stakeholders in attendance) and in VA in May 2009 (~50 stakeholders in attendance).
Publications
- No publications reported this period
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