terminals in full second-level blocks and 70% in 

 nearby first-level blocks. Two aphid predators, 

 sjrrphid and cecidomyiid flies, were slightly 

 more prevalent in second-level blocks than in 

 first-level blocks. These high levels indicate 

 that predators achieved control of GAA in both 

 second-level and first- level IPM blocks. Infesta- 

 tion of terminals by wooly apple aphid (WAA) 

 was similar in second-level and first-level 

 blocks, but in both types of blocks WAA popula- 

 tions were lower in 1992 than in 1991 (Table 6). 



Foliar Pests and Predators: 

 Transitional Second-level IPM 



Very few Amblysieus fallacis predatory 

 mites were seen in transitional second-level or 

 nearby first-level blocks luitU September (Table 

 5). Mite levels in most cases remained low, 

 although one grower had European red mite 

 populations in his transitional second-level 

 block sufficient to warrant treatment with a 

 miticide in mid-summer (Table 2). Mid-season 

 miticides were applied in four of the six first- 

 level blocks, with an average of 1.1 dosage 

 equivalents of miticide per block (Table 2). 



Potato leafhopper infestation levels on ter- 

 minals averaged higher in transitional second- 

 level blocks than in nearby first-level blocks. In 

 transitional second-level blocks, white apple 

 leafhoppers infested 6% and potato leaflioppers 

 7% of terminals at their peak, while in nearby 

 first-level blocks, both white apple leafhopper 

 and potato leafhopper populations peaked at 

 about 1% of terminals infested. White apple 

 leafhopper injury to frmt at harvest was statis- 

 tically simUar in transitioned second-level and 

 first-level blocks, and potato leaQiopper injury 

 also was statistically similar in transitioned 

 second-level and first-level blocks (Table 6). In 

 no case did these insects cause serious problems 

 for growers. 



All six transitional second-level blocks were 

 treated with DimiUn against first generation 

 leafminers. Only two growers treated their 

 first-level blocks for leafminers (Table 2). Peak 

 numbers of mines on 100 leaves averaged 10.8 

 in transitional second-level blocks and 11.8 in 

 first-level blocks, considerably lower in both 



blocks than in 1991 (Table 6). 



GAA populations were higher in 1992 than 

 in 1991. At their peak, they infested an average 

 of 77% of terminals in transitional second-level 

 blocks and 65% of terminals in nearby first-level 

 blocks. Predator populations were higher this 

 year as well; their populations peaked at an 

 average of 55% of terminals infested in transi- 

 tional second-level blocks and 57% of terminals 

 in first-level blocks. In both cases predators 

 were adequate to provide control of aphid pests. 

 Similar numbers of terminals in the transitional 

 second-level blocks and in first-level blocks were 

 infested with wooly apple aphids (Table 6). 



Conclusions 



We continue to be pleased with the success of 

 implementation of second-level IPM for apple 

 insects and mites in six- to nine-acre blocks in 

 commercial orchards. In 1992, full second-level 

 IPM blocks received 28% less total dosage 

 equivalents of insecticide and miticide and 18% 

 fewer total spray events for insects and mites 

 than first-level IPM blocks. Excluding pre- 

 bloom sprays of oil (non-toxic in the environ- 

 ment), dosage equivalents were reduced 30% 

 and spray events were reduced 22%. Despite 

 this difference, total firut injury by insects was 

 similar in full second-level and first-level IPM 

 blocks, and peak populations of foUar pests were 

 not different, except for leafhoppers. 



Early season fruit injury from PC, TPB, 

 EAS, and GFW was low in all cases, as was finiit 

 injury by CM, LR, LAW, and SJS. GAA were 

 controlled by predators in both second-level and 

 first-level blocks. We continue to work toward 

 gaining registration of Dimilin, which provides 

 good control of leafminers without disrupting 

 beneficial parasites and predators. 



Transitional second-level IPM appears to be 

 an effective reduced-spray management pro- 

 gram for insect and mite pests in commercial 

 orchards. In 1992, transitional second-level 

 IPM blocks received 37% less total dosage 

 equivalents of insecticide and miticide and 12% 

 fewer total spray events for insects and mites 

 than first-level IPM blocks. Total fruit injury by 

 insects did, however, average sUghtly but not 



30 



Fruit Notes, Winter, 1993 



