Madsen (1982), and Bostonian et al. (1984) and 

 other authors. 



The decreased number of spiders in first- 

 level IPM blocks may have been due not only to 

 direct contact toxicity of insecticide but also to 

 insecticide acting as a repellant to spiders, tox- 

 icity to spiders of prey feeding on insecticide- 

 treated plant material, lack of prey insects (as a 

 result of prey being killed or driven away by 

 pesticide), destruction of webs by turbulence 

 created by spraying, or a combination of these 

 and other factors. 



Several questions stiU remain to be an- 

 swered. One of them is whether or not the 

 increased number of spiders in second-level IPM 

 blocks is great enough to contribute signifi- 

 cantly to the control of foliar pests. Can spiders 

 prey effectively on leafminers, leafhoppers, and 

 mites? Will they eat enough of such pests to 

 make a difference? We plan to address these 

 questions in the near futiu-e. 



Acknowledgements 



This project was funded by the Massachu- 

 setts Society for Promoting Agriculture, the 

 USDA Northeast Regional IPM Competitive 

 Grants Program, and State/Federal IPM funds. 



We gratefully acknowledge this funding. We are 

 grateful to the following growers for their par- 

 ticipation and support: Dana Clark, Dave Chan- 

 dler, Dick Gilmore, Tony Lincoln, Wayne Rice, 

 and Joe Sincuk. 



Literature Cited 



Bostonian, N.J., CD. Dondale, M.R. Binns, D. 

 Pitre. 1984. Effects of pesticide use on spiders 

 (Araneae) in Quebec apple orchards. Canadian 

 Entomologist 116:663-675. 



Madsen, H.F. and B.J. Madsen. 1982. Popula- 

 tions of beneficial and pest arthropods in an 

 organic and a pesticide treated apple orchard in 

 British Columbia. Canadian Entomologist 

 114:1083-1088. 



Mansour, F., D. Rosen, and A. Sulov. 1980. A 

 survey of spider populations (Araneae) in 

 sprayed and unsprayed apple orchards in Israel 

 and their ability to feed on larvae of Spodoptera 

 littoralis (Boisd.). Acta Oecologica: Oecol. 

 Applic. 1:189-197. 



Riechert,S.E. and L. Bishop. 1990. Prey control 

 by an assemblage of generalist predators: spi- 

 ders in garden test systems. Ecology 71:1441- 

 1450. 



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Fruit Notes, Winter, 1993 



23 



