plied to apple tree foliage and fruit has little or no ef- 

 fect on apple maggot fly mortality and oviposition. 

 There may be two reasons for the ineffectiveness of 

 Provado spray on tree foliage and fruit against apple 

 maggot flies. First, Provado is a systemic insecticide, 

 and is quickly absorbed by foliage (and perhaps also 

 fmit) once sprayed. Thus, it kills pests that suck sap 

 from the interior of foliage but does not remain on plant 

 surfaces long enough to kill pests, such as apple mag- 

 got flies, that do not suck plant sap. Second, Provado 

 on exterior surfaces of plants is subject to rapid degra- 

 dation by sunlight. Nevertheless, when applied to- 

 gether with latex paint to red spheres, Provado, even 

 at very low doses, has provided excellent control of 

 apple maggot flies alighting on treated spheres for up 



to three months after initial application. Thus far, it 

 has proven more effective than any other insecticide 

 that we have evaluated for this purpose. 



Acknowledgements 



We thank Richard H. Ackerman from Bayer Cor- 

 poration for providing us with samples of imidacloprid 

 and John Clark and David Ferro from our department 

 for helpful suggestions. This work was supported by 

 funds from USDA Cooperative Agreement 58-3620- 

 104, the Northeast Regional IPM Competitive Grants 

 programs and the Washington State Tree Fruit Research 

 Commission. 



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Fruit Notes, Volume 63 (Number 2), Spring, 1998 



