significantly higher in transitional second-level 

 blocks than in first-level blocks. Peak popula- 

 tions of foUar pests were Uttle different, except 

 for leaflioppers, which were somewhat more 

 abundant in the transitional second-level 

 blocks. 



For 1991 and 1992, combined, transitional 

 second-level IPM blocks received about 17% 

 more insecticide and miticide and 23% more 

 spray events than full second-level IPM blocks. 

 Insect-caused fi*uit injury averaged over both 

 years was virtually identical in full and transi- 

 tional second-level blocks. 



Our main concern with the benefits of tran- 

 sitional second-level IPM over the long-term Ues 

 with the potential buildup of AMF from infested 

 fallen drops not removed at harvest. The odor 

 baits employed with the interception traps im- 

 der full second-level IPM can attract these AMF. 

 A second concern with the long-term benefits of 

 transitional second- level IPM Hes with potential 

 negative effects of perimeter-row sprays on im- 

 migration of beneficial predators and parasites. 

 Two more years of planned comparison of full 

 second-level IPM vs. transitional second-level 

 IPM vs. first-level IPM orchard practices should 

 provide more insight into the benefits and costs 

 of each practice. 



A second year of trials has not answered all 

 of our questions about two foUar pests, mites 

 and leafhoppers. Although mites were rarely a 

 problem in this wet, cool summer, predator 

 populations were low even where pest mites 

 existed in numbers sufficient to support them. 

 We need to learn more about overwintering 

 locations of mite predators and about the exact 

 identity of predators in Massachusetts or- 

 chgirds. Further monitoring of the newly-re- 

 leased predator, Typhlodemus pyri, will help us 

 to determine if release of this pesticide-resistant 

 predator could help to control pest mites in 

 Massachusetts orchards. We will continue to 

 study the role of spiders in pre3dng on leafinLners 

 in mines and on leafhopper njrmphs. 



In our judgement, the key to grower adop- 

 tion of second- level IPM practices for insects and 

 mites hes in availabihty of a low-cost approach 

 to interception trapping of AMF. At present, 

 costs of labor and materials to employ odor- 



baited sticky red spheres exceeds by nearly 

 twofold the cost of applying insecticide sprays 

 against AMF and other summer finiit-injuring 

 insects. The fi:^quent cleaning of sticky traps 

 necessary to provide an effective capturing sur- 

 face is a major component of the cost of this 

 system. We believe that development of pesti- 

 cide-treated spheres (now in progress) as a sub- 

 stitute for sticky spheres will provide a cost- 

 effective approach to using interception traps 

 for this insect. 



Even if we assume that a pesticide-treated 

 sphere interception trap system for AMF will be 

 no more costly than applying insecticide after 

 mid-Jime, why should a grower want to switch 

 from an insecticide-based first-level IPM ap- 

 proach? We believe there are at least four 

 reasons for doing so: ( 1) saving money on sprays 

 against foliar pests by allowing beneficial natu- 

 ral enemies to build up and provide control in the 

 absence of pesticide use; (2) reducing the UkeU- 

 hood that foHar pests will develop resistance to 

 pesticides, thereby preserving the long-term ef- 

 fectiveness of these pesticides; (3) reducing pes- 

 ticide intrusions on neighbors or the environ- 

 ment adjacent to orchards; and (4) greatly re- 

 ducing or eliminating pesticide residues on finait 

 at harvest. For some growers, these potential 

 advantages could be large. 



Acknowledgements 



This project was funded by the Massachu- 

 setts Society for Promoting Agriculture, the 

 USDA Northeast Regional IPM Competitive 

 IPM Grants Program, State/Federal IPM funds, 

 and the Northeast Region Sustainable Agricul- 

 ture Research and Education Program (for- 

 merly LISA). We gratefully acknowledge this 

 funding. We are also grateful for the participa- 

 tion and support of the following growers: Bill 

 Broderick, Dave Chandler, Dana Clark, Dick, 

 Greg, and Kevin Gilmore, Tony Lincoln, Jesse 

 and Wayne Rice, Joe Sincuk, Dave Shearer, Tim 

 Smith, £md Barry and Bud Wiles, and for the 

 scouting assistance of Ryan Elliott, Kathy 

 Hickey, James Gamble, £md Peter Winnick of 

 the Department of Plant Pathology. 



Fruit Notes, Winter, 1993 



31 



