Progress 09/01/01 to 08/31/04
Outputs
During the course of the project, several experiments were performed to develop and evaluate a new prototype of pesticide-treated sphere (PTS) for apple maggot (AM) control in commercial orchards. In 2003 we compared a new PTS consisting of an unpainted red plastic sphere topped by a sugar-paraffin (feeding stimulant) disc that contained a small amount of Spinosad as fly killing agent against the version of PTS evaluated in 2002. The 2002 version of PTS consisted of a sphere coated with red latex paint containing a small amount of imidacloprid as the fly killing agent topped by a sugar-paraffin disc containing no insecticide. The objective of a second study in 2003 was to compare different concentrations of spinosad (0.5%, 1.0%, 2.0% or 4.0%) for toxicity to adult flies in the laboratory after 6, 9 and 12 weeks of deployment in orchards. In 2003 we also aimed at determining, in the laboratory, the ability of 2003-version PTS having sugar-paraffin discs containing
varying amounts of spinosad (either 0, 0.001, 0.01, 0.1 or 1.0% spinosad) at killing flies after being submitted to different amounts of artificial rain (1, 4, 7 or 10 inches) using a laboratory chamber. From our first 2003 study we determined that the 2003 version of PTS topped by discs containing 4% spinosad outperformed both 2002-version PTS (whose surface contained paint mixed with imidacloprid). It also exceeded control by insecticide sprayed for AM. From our second study we found that after 6 and 9 weeks of exposure in orchard trees, 2003-version PTS topped by discs containing 0.5%, 1.0%, 2.0% or 4.0% spinosad were equally effective at killing adults placed directly on the spheres in the laboratory. From our last experiment, we learned that the concentration of spinosad in the disc needs to be at least 0.1% to be effective after 10 inches of artificial rainfall. Thus, discs containing sugar, paraffin and spinosad at a concentration of 1% should offer effective season-long
control of AM in commercial orchards. In 2004 we evaluated the ultimate design of PTS: a contoured compressed top cap bearing sugar (as feeding stimulant), spinosad (Entrust), and paraffin wax. The cap was then coupled to a hollow plastic sphere. This new PTS (named CurveBalls) was evaluated in 14 commercial apple orchards in MA, and provided the same level of season-long control of AM as 3 insecticide applications. In further field evaluations we compared the effectiveness of CurveBalls versus odor-baited sticky spheres versus degree of control offered by 3 applications of insecticide. Results confirmed that CurveBalls out-performed sticky spheres and showed same level of control offered by insecticide applications. Our 2004 tests in the laboratory also revealed that CurveBalls retained their killing power even 12 weeks after deployment in commercial orchards (>80 mortality).
Impacts
Our 2003 findings paved the way for a new type of PTS for direct control of apple maggot. This new PTS is termed CurveBall and will be available to commercial apple growers at a relatively inexpensive cost possibly as early as 2005. Because Entrust is labeled for use in organic agriculture, we strongly believe that CurveBalls will receive approval by EPA for direct control of AMF. This behavioral approach for controlling AM has not only proven as effective but also as affordable as insecticide sprays. These findings will impact at least 500 apple growers throughout the Northeast and in other regions where AM is a problem. The simple and inexpensive trapping system developed by Ron Prokopy for directly controlling AMF without need of any insecticide spray, and under a wide range of orchard architectures and conditions, is currently in place in Massachusetts orchards. The set of cooperators on this project are working in blocks, not whole orchards. In Massachusetts, we
have 14 blocks with 8 growers (Chandler, A. Clarke, Tougas, Broderick, Carlson, Martin, Davis and Lincoln) while we have at least two blocks each in 6 other states (NY, VT, CT, NH, ME and RI).
Publications
- Prokopy, R.J., Chandler, B., and Wright, S.E. 2004. Improved sugar delivery onto pesticide-treated spheres for controlling Rhagoletis pomonella flies (Diptera: Tephritidae). Canadian Entomologist 135: 909-918.
- Prokopy, R.J., Jacome, I., Bigurra, E., and Blanco, M. 2005. Evaluation of pesticide-treated spheres for control of apple maggot flies in 2003 (submitted to Fruit Notes of New England).
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Progress 09/01/02 to 08/31/03
Outputs
In lab tests in fall 2002 and spring 2003, we evaluated prototypes of new and safe approaches to delivering insecticide and sugar onto red spheres for direct control of alighting apple maggot flies (AMF). New approaches became advisable because of EPA concern with potential adverse environmental effects of current-version pesticide-treated spheres: a hardened disc of sucrose and paraffin atop a sphere coated with latex paint containing imidacloprid as insecticide. Among prototypes, the most promising was a plastic sphere topped by a hardened disc comprised of sugar, paraffin wax and spinosad (Entrust) as insecticide. Under high humidity, dew or rainfall, sugar and Entrust leach from the disc onto the sphere surface. In a test of 6 commercial apple orchards from July through September 2003, each of three 1/2 acre plots was surrounded by odor-baited red spheres, with the intent of intercepting immigrating AMF before entry into plots and oviposition in apples. Untreated
spheres topped by 200 g discs comprised of sugar, paraffin wax and Entrust provided season-long AMF control equal to that of (a) imidacloprid-treated spheres topped by 200 g discs of sugar and paraffin wax alone, (b) sticky-coated spheres and (c) 2-3 sprays of organophosphate insecticide applied to a fourth plot in each orchard. Entrust is labelled for application in organic agriculture and will be more likely than imidacloprid to receive EPA approval for use in conjunction with red spheres for AMF control.
Impacts
A new prototype of pesticide-treated sphere for AMF control was devised and evaluated in commercial orchards. It consists of a red sphere topped by a 200 g disc of hardened sugar and paraffin wax containing spinosad as a safe and effective insecticide. This prototype provided effective season-long AMF control.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
Under Objective 1, from October '01 to June '02, we investigated variables affecting performance and durability of sucrose/paraffin discs atop plastic pesticide-treated black spheres for apple maggot fly (AMF) control. A continuous supply of sucrose (from disc) is needed on sphere surface to ensure feeding and pesticide uptake by alighting AMF. Among several paraffins assessed, one with a melting point of 130 degrees F proved best for combining with sucrose. Among several proportions of wax: sucrose assessed, a proportion of 20:80 proved optimum. Among several configurations of top caps assessed, one whose top surface was neither flat nor fluted (channeled), but rather constructed with shallow depressions proved best for retaining some but not too much rainfall (which percolated through the top cap and carried sucrose onto the sphere surface). Among several amounts of hydraulic pressure evaluated to compress paraffin and sucrose, 25 tons proved best for achieving
discs not so soft as to crumble, but not so hard as to deny penetrability of rainfall retained by the top-surface depressions. Among several sizes of top caps evaluated, one that measured 7.5 cm diameter x 3 cm tall (weighing 150 grams) proved optimum for balancing maximum attractiveness of sphere to AMF with optimum release of sucrose onto the sphere surface over a 12-week period. Among several colors of top caps evaluated, one that was white and provided maximum contrast with the sphere below proved best for AMF attractiveness. Among several approaches evaluated for deterring feeding on discs by rodents, enveloping a disc in 1/8-inch mesh hardware cloth (compressed onto disc surface under hydraulic pressure) proved most effective. Under Objective 2, from July to September '02, we evaluated in 7 commercial orchards spheres coated with black latex paint containing 4% a.i. imidacloprid and topped by paraffin/sucrose discs that had optimum characteristics as determined under Objective
1. Half-acre plots of apple trees surrounded by odor-baited pesticide-treated spheres 5 m apart proved just as effective in controlling AMF as 2-3 sprays of organophosphate insecticide.
Impacts
Major progress was made toward optimizing characteristics of sugar/paraffin discs atop pesticide-treated spheres for apple maggot fly control. The 150-gram discs selected for commercial-orchard evaluation provided sufficient sucrose to sphere surfaces (without requiring replacement) for the entire 12-week apple maggot fly season and were completely unaffected by rodents. Excellent season-long control of apple maggot was achieved using such spheres in commercial orchards. Even so, some minor adjustments in disc characteristics are needed before discs atop pesticide-treated spheres can be recommended to growers.
Publications
- Wright, S., B. Chandler and R. Prokopy. 2001. Improvement of sugar-delivery systems for rain- activated pesticide-treated spheres. Fruit Notes of New England 66:25-29.
- Chandler, B. and R. Prokopy. 2001. Residual activity of insecticide on wooden and plastic pesticide-treated spheres. Fruit Notes of New England 66:35-36.
- La Fleur, G., J. Rull and R. Prokopy. 2001. Do sugar caps atop wooden pesticide-treated spheres affect apple maggot fly attraction of spheres? Fruit Notes of New England 66:37-39.
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