over the 21-day pre-test period (including 15 cm of 

 rainfall), 30% of AMF that visited a smooth wooden 

 sphere died within 24 hours compared with 0% deaths 

 among AMF that visited sock-covered spheres. Obvi- 

 ously, our idea that using an absorbent material such 

 as a cotton red sock to reduce residue decay was not a 

 fruitful one. It appeared to us that arriving AMF were 

 rather reluctant to feed when on a sock-covered sur- 

 face, possibly owing to an adverse effect of the mesh of 

 cotton fiber on fly foraging behavior. We are very 

 encouraged, however, by the substantial rate of mor- 

 tality of AMF that arrived on smooth, painted, wooden 

 spheres exposed to a high level of rainfall over the 21- 

 day pre-test period. It seemed that after drying, the 

 Vaporguard-corn syrup mixture formed a rather hard 

 glaze on the sphere surface and thereby afforded con- 

 siderable protection against residue decay. 



We made no clear-cut comparisons between Va- 

 porguard and a polymeric thickener as residue-extend- 

 ing agents. Vaporguard had the advantage that both 

 liquid and powdered fly feeding stimulant and pesti- 

 cide can be mixed with it. We suggest, however, that 

 polymeric thickener, which is miscible only with pow- 

 dered fly feeding stimulant and pesticide and forms a 

 hard glaze after drying, will prove the more effective 

 under heavy rainfall. 



Conclusions 



We are most encouraged by the results of our first 



summer of research evaluating mixtures of fly feeding 

 stimulants and pesticides and ways of protecting such 

 mixtures against residue decay. Our combined find- 

 ings to date suggest that for our tests in the near future 

 (the summer of 1990), the most effective mixture of 

 materials is a paste containing table sugar, Lannate 

 technical powder, and a polymer thickener as a resi- 

 due-extending agent. Present data suggest that we 

 would need to re- treat spheres with this mixture every 

 3 weeks to maintain high effectiveness. Hopefully, an 

 equally or more effective but safer pesticide than Lan- 

 nate and a more effective residue-extending agent may 

 be on the horizon. 



We realize that a large number of pesticide- treated 

 red spheres on perimeter apple trees may invite pas- 

 sers-by to "pick" and handle these curious "apples." 

 We are experimenting with methods that would pre- 

 vent human fingers from touching the sphere surface 

 but would not affect AMF access to the sphere surface. 



Acknowledgements 



We thank the Northeast Regional Project on Inte- 

 grated Management of Apple Pests (NE-156), Massa- 

 chusetts Agricultural Experiment Station Project 604, 

 and DuPont Corporation for supplying materials for 

 this work. 



20 



Fruit Notes, Spring, 1990 



