leafminer were higher in second-level than in 

 first-level blocks (Table 2). 



Green apple aphids infested 73% of sampled 

 terminals in full second-level blocks and 70% in 

 nearby first-level blocks when sampled in early 

 July (Table 5). Two aphid predators, syrphid 

 and cecidomyiid flies, averaged 69% in full sec- 

 ond-level blocks and 59% in nearby first-level 

 blocks. These high levels of predation indicate 

 that predators achieved control of green apple 

 aphids in both second-level and first-level IPM 

 blocks. Infestation of terminals by wooly apple 

 aphid was similar in second-level and in first- 

 level blocks (21% and 17%, respectively). 



Little is known about the effects of spiders in 

 orchards, but they may play a role as predators, 

 particularly under conditions of reduced pesti- 

 cide applications. Spiders were monitored by 

 jarring limbs of trees with a rubber mallet and 

 catching any spiders that fell in a tray held 

 beneath the branch. Although the number of 

 spiders caught increased as the summer pro- 

 gressed, the numbers caught in the full second- 

 level blocks never differed significantly from 

 those captured in nearby first-level blocks 

 (Table 7). This similarity may be explained by 

 the patterns of insecticide and miticide use in 

 the two blocks, explained below. 



Total insecticide and miticide use in full 

 second-level blocks was only slightly lower than 

 in nearby first-level blocks (6.0 vs. 6.4 dosage 



equivalents) (Table 2). This result contrasts 

 with pesticide records from previous years, 

 when an average of about 9 dosage equivalents 

 of insecticide and miticide were applied to first- 

 level IPM blocks. (In this study in 1991, 8.7 

 dosage equivalents were applied to first-level 

 IPM blocks paired with transitional second level 

 blocks.) Several factors contributed to an in- 

 crease in pesticide use in second-level blocks, 

 including the hot, dry weather which contrib- 

 uted to mite buildup, a hawthorn tree on the 

 edge of one block which contributed to high AMF 

 trap captures, and lack of treatment of some 

 nearby blocks. Other factors, including the 

 increased monitoring resulting from this project 

 and the lack of an attractive insecticidal option 

 for leafminer control, caused a decrease in pes- 

 ticide use in first-level blocks. 



Transitional Second-level IPM 



Early Season Management. Monitoring 

 in transitional second-level blocks was identical 

 to that conducted in full second-level blocks. 

 Combined injury from tarnished plant bug, 

 plum curculio, European apple sawfly, and 

 green fruitworm averaged 5.1% in transitional 

 second-level blocks and 3.6% in first-level blocks 

 (Table 1). Pesticide use against early season 

 pests was similar in the two types of blocks 

 (Table 2). 



Fruit Notes, Spring, 1992 



11 



