fluence of ground cover and orchard border area compo- 

 sition on mite predator abundance, it appears that a sub- 

 stantial number of predatory mites may be wind-blown 

 into orchards from plants surrounding the orchard. Possi- 

 bly such predators are being killed as they contact the 

 sprayed border row apple trees. Further work is planned 

 to evaluate this possibility. 



All other foliage-injuring pests (woolly aphids, leaf- 

 hoppers, leafminers) were fairly low in abundance in both 

 1987 and 1988 in both border-row sprayed blocks and fully- 

 sprayed blocks. 



In sum, we are pleased with the results of the border- 

 row spray program in virtually every respect except the 

 failure of predatory mites to build to effective numbers. 



Border Row Sprees With Predator Releases 



In 1988 6 bordcr-row-sprayed blocks and 6 fully- 

 sprayed blocks were established in which Amblyseiusfalla- 

 cis mite predators were released at the rate of 500 to 1000 

 predator eggs, nymphs, or adults under each of 6 to 7 trees 

 per block (every 4th tree of the block interior) in July. 



As in the border-row-sprayed blocks without mite 

 predator releases, there was little difference between 

 border-row sprayed and fully-sprayed blocks in the 

 amount of fruit injury by apple maggots, codling moths, or 

 summer leafrollers or in populations of woolly aphids, 

 leafhoppers, or leafminers (Table 3). 



Of prime interest is the result of the mite predator re- 

 leases. Amblyseius fallacis were about equally abundant in 

 both the border-row-sprayed and the fully-sprayed blocks 

 and were far more abundant in both than in comparable 

 blocks (Table 2) where no predators were released. The 

 released predators had genotypes largely resistant to 

 Guthion and Imidan. This situation may explain the much 

 greater abundance of this species in the blocks where they 

 were released than in border-row-sprayed and fully- 

 sprayed blocks where they were not released. These 

 results are encouraging in terms of released predator sur- 

 vival during summer in sprayed blocks. We collected data 

 in each block on the abundance of pest mites and Ambly- 

 seius fallacis on trees where the latter were released vs. im- 

 mediately adjacent trees where they were not released. 



These data (Table 3) suggest that the numbers of released 

 predators were too few to have affected populations of pest 

 mites on the trees and that released predators were rather 

 slow to move away from the trees under which they were 

 released. This result suggests that in the future, much 

 greater numbers of predator mites should be released on 

 a greater proportion of trees in the orchard if such releases 

 are to provide meaningful biological control of mites. 



Conclusion 



In conclusion, we are highly encouraged by most of the 

 results of these past 2 years of second-stage IPM experi- 

 mentation. We have a few "bugs" to iron out to render the 

 second-stage approach more cost-effective and labor- 

 appealing (especially development of a system to replace 

 sticky as a method of killing apple maggot flies that arrive 

 on spheres). Presently, we see 2 alternative routes to 

 achieving potential second-stage IPM success on a practi- 

 cal level: (1) no insecticide or miticide used after early 

 June, employing baited, pesticide-treated, non-sticky 

 spheres around the orchard perimeter to intercept and kill 

 apple maggot flies, removing all apple trees within 100 

 yards or so of the orchard perimeter, and allowing mite and 

 aphid predators to immigrate into and build up in such 

 blocks in a pesticide-free atmosphere; or (2) using border 

 row sprays as a substitute for employing maggot fly spheres 

 and releasing very large numbers of pesticide-resistant 

 mite predators (possibly on an annual basis) on a high pro- 

 portion of trees. 



Acknowledgements 



We thank the Massachusetts Society for the Promo- 

 tion of Agriculture, the USDA Israel Binational Agricul- 

 tural Research and Development Fund (BARD) under 

 grant US-807-84, and the Northeast Regional Project on 

 Integrated Management of Apple Pests (NE-156) for sup- 

 porting our work on second-stage apple IPM. Special 

 thanks to Betsy Frederick, Esther Ruiz, Phuong Nguyen, 

 and Joseph Shepherd, who worked on the 1988 studies. 

 Bill Coli, Kathleen Leahy, and Bill Pyne also participated 

 in this program. 



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