Table 1 . Mortality of AMF after exposure to wooden or plastic PTS. 

 All PTS were exposed on unsprayed apple trees for 12 weeks before 

 testing. 



Sphere 



Wooden 



Wooden 



Wooden 



Plastic 



Plastic 



Control 



Sphere surface 

 clean when 

 paint applied 



Paint contained 

 20% sucrose 

 when applied 



AMF mortality (%) 

 72 hours after 

 exposure 



Yes 

 Yes 

 No* 

 Yes 

 Yes 

 Yes 



No 

 Yes 

 Yes 

 No 

 Yes 

 No 



100 



100 



90 



90 



100 







Uncleaned spheres used in commercial orchards in 2000. 



died as a consequence of feeding on the sphere surface. 

 During the 12-week period of field exposure, 10.7 

 inches of rain fell on the spheres. 



Conclusions 



Our findings indicate that latex paint containing 

 4% (a.i.) imidacloprid applied to plastic spheres (after 

 roughening of the sphere surface) conferred an amount 

 of residual toxicity to AMF essentially equal to that of 



the same mixture applied to wooden spheres, and did Acknowledgement 

 so after 12 weeks of field exposure to 10.7 inches of 

 rainfall. Our findings also indicate that addition of 

 20% sucrose to the paint-pesticide mixture did not 

 detectably affect residual activity of paint or pesticide. 



Finally, we found that it is not necessary to clean 

 spheres prior to repainting with latex paint and 

 insecticide in order to obtain a high level of mortality 

 of alighting AMF. 



Together, these findings pave the way for 

 substitution of durable plastic spheres for wooden 

 spheres in the pursuit of effective PTS for controlling 

 AMF. 



This work was supported by grants from the USDA 

 CSREES Pest Management Alternatives Program and 

 Crops at Risk Program. 



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36 



Fruit Notes, Volume 66, 2001 



