Evaluation of Pesticide-Treated 

 Spheres for Control of 

 Apple Maggot Flies in 2003 



Ronald J. Prokopy, Isabel Jacome, Everardo Bigurra, and Marina Blanco 



Department of Plant, Soil, & Insect Science, University of Massachusetts 



Bradley Chandler and Starker Wright 



Pest Management Innovations Inc., Harpers Ferry West Virginia 



In the two preceding articles in this issue of Fruit 

 Notes, we described results of recent research aimed 

 at optimizing ( 1 ) distances between odor-baited spheres 

 on perimeter trees for control of apple maggot flies 

 (AMF) and (2) placement of spheres within the tree 

 canopy. These results were obtained using spheres 

 coated with Tangletrap as the agent for capturing and 

 killing arriving AMF. If odor-baited spheres are to be 

 used extensively for AMF control in commercial 

 orchards, a substitute for Tangletrap as lly killing agent 

 must be found. One potential substitute that we began 

 to develop in 1 990 and have been refining ever since is 

 a sphere whose surface has pesticide as fly killing agent 

 and sugar as feeding stimulant to induce arriving AMF 

 to ingest the pesticide. 



In the 2001 issue of Fruit Notes and in a 2003 

 issue of the Canadian Entomologist, we described 

 results of commercial-orchard tests of pesticide-treated 

 spheres (PTS) for control of AMF. The tests were 

 conducted in 2001 and 2002, respectively. Combined 

 findings led us to conclude that sugar as feeding 

 stimulant can best be maintained on the sphere surface 

 via periodic seepage from a disc atop the sphere that 

 contains a mixture of highly compressed sugar and 

 paraffin wax. 



Here, we descnbe results of tests conducted in 2003 

 that compare the version of PTS evaluated in 2002 with 

 a new version of PTS developed in 2003 for AMF 

 control. The 2002 version involved a plastic sphere 

 coated with red latex paint containing a small amount 

 of imidacloprid as fly killing agent, topped by a sugar- 

 paraffin disc. The 2003 version involved an unpainted 



red plastic sphere topped by a sugar-paraffin disc that 

 contained a small amount of spinosad as fly killing agent. 

 This version relied on seepage of both spinosad and 

 sugar from the disc onto the sphere surface under high 

 humidity, dew, or rainfall. 



Material & Methods 



For the 2002 PTS version, the sphere was 3.5 

 inches in diameter and received a coat of latex paint 

 containing 2% (a. i.) of imidacloprid (Provado). The 

 disc atop the sphere was composed of 80% table sugar 

 (sucrose) and 20% paraffin wax (200 grams total 

 mass). It measured 3 inches in diameter x 1.5 inches 

 tall. It was white in color, compressed under 20 tons of 

 hydraulic pressure and embedded in a wire guard to 

 protect It from consumption by rodents. 



For the 2003 PTS version, the 3.5-inche sphere 

 received no paint or pesticide on the surface. It was 

 topped by a disc (similar to the 2002 version) that 

 contained one of several different concentrations 

 (ranging from 0.001 to 4.0% a.i.) of spinosad (Entrust) 

 thoroughly mixed with the sugar. 



In our first experiment, spheres were evaluated in 

 six commercial orchards in MA, each of which contained 

 four 1/2-acre plots of apple trees. Three of the plots 

 received no insecticide after mid-June and were 

 surrounded by either 2002-version PTS, 2003-version 

 PTS (containing 4.0% spinosad), or sticky spheres 

 placed 6-8 yards apart on perimeter trees. Spheres 

 were deployed during the first week of July and 

 remained for 12 weeks. Discs atop PTS were not 



Fruit Notes, Volume 69, Spring, 2004 



21 



