examined carefully for 

 maggot egglaying stings. 



Results 



presence of apple 



Results of laboratory assays of residual 

 efifectiveness of pesticide-treated spheres against 

 flies (Table 1) show that after four weeks of 

 exposure and two inches of rainfall, 80% of flies 

 placed on 1995-version spheres died compared 

 with 90% that died when placed on 1996- 

 version spheres. In 1995, after ten weeks of 

 exposure (5.7 inches of rain), 1995-version 

 spheres killed only 30% of tested flies. In 1996, 



after ten weeks of exposure (7.2 inches of rain), 

 1996-version spheres killed 70% of tested flies. 

 In fact, for every period when assayed, 1996- 

 version spheres outperformed 1995-version 

 spheres (Table 1). Retreating spheres with 16% 

 sucrose solution (in water) after twelve weeks 

 of exposure restored effectiveness of 1995 

 spheres to a level of 70% fly kill, demonstrating 

 that loss of sucrose as feeding stimulant and 

 not loss of dimethoate as toxicant was the 

 principal factor responsible for decreasing 

 performance. 



Results of tests assessing the capability of 

 pesticide-treated spheres for providing direct 



Fruit Notes, volume 62 (Number 2), Spring, 1997 



