All remaining 1 1 AMF flew from a pesticide-treated 

 sphere to nearby foliage. Of these, six were cap- 

 tured. All six died within 24 hours. The other five 

 AMF evaded capture. Of the 19 AMF alighting 

 on untreated check spheres, the median duration 

 of stay was about 4 minutes and none died while 

 on a sphere. Unfortunately, none could be cap- 

 tured after departing an untreated sphere, as flight 

 was too fast and far to permit capture. 



Conclusions 



Results of this study of responses of wild-popu- 

 lation AMF in a commercial orchard to wooden 

 spheres treated with imidacloprid, sucrose and la- 

 tex paint confirm results of a study reported in the 



preceding article conducted using laboratory-main- Acknowledgments 

 tained AMF. Among all wild-population AMF 

 observed here to alight on pesticide-treated spheres, 

 86% (31 of 36) died within 24 hours and most 

 died within 1 hour. The fate of the 14% that were 



not captured after alighting is unknown. Some of 

 these also may have died. In the preceding article, 

 data showed that pesticide-treated spheres com- 

 parable both in type (2% a.i. imidacloprid) and 

 field-exposure before testing (3 weeks) to those 

 used here yielded 75% mortality of tested AMF. It 

 is thus reassuring to know from this study of wild- 

 population AMF that we can use response patterns 

 of laboratory-maintained AMF placed directly on 

 pesticide-treated spheres as an accurate guide to 

 the performance of pesticide-treated spheres in 

 commercial orchards. It is also reassuring to know 

 that pesticide-treated spheres treated with 2% a.i. 

 imidacloprid and sucrose are highly effective 

 against AMF. 



This work was supported by a grant from the 

 Washington Tree Fruit Research Commission and 

 a USDA SEA CSRESS grant (#97-34365-5043). 



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Fruit Notes, Volume 63 (Number 4), Fall, 1998 



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