-24- 



liarvest: 100 fruit per tree on 6-24 trees per block, depending 

 on block size. Each sampled fruit was examined carefully, and any 

 insect injury, no matter how slight, was recorded. The data in- 

 clude about 151,000 apples sampled over 5 years from 87 "good- 

 cooperator" I PM blocks and about 64,000 apples sampled over 5 

 years from 40 check blocks. Sampled I PM and check blocks were 

 scattered from east-central to west-central portions of the state. 



The data show that total insect -caused fruit injury averaged 

 3.18% in the IPM blocks versus 3.80% in the check blocks. The 5 

 most injurious pests in the IPM blocks were, in decreasing order 

 of importance, tarnished plant bug, plum curculio, San Jose scale, 

 European apple sawfly, and apple maggot. Together, these 5 pests 

 accounted for 98% of all insect - inj ured fruit in IPM blocks. 

 These same 5 pests accounted for 95% of all insect - injured fruit 

 in the check blocks, with plant bug again being the most injurious. 



Do all insect injuries detected on trees at harvest by field 

 scouts result in downgrading of fruit in the packing shed? To help 

 answer this question, we refer to a packout survey published in 

 FRUIT NOTES 46(3). This survey involved examination of about 

 400,000 apples by packing shed personnel and about 60,000 of the 

 culls by Glenn Morin. It was conducted in 16 Massachusetts packing 

 sheds on 1980-grown fruit. Some of the orchards and blocks sampled 

 in the packout study were the same as those sampled for on-tree 

 injury in 1980, but several were not. Although this lack of 

 direct correspondence of sampled blocks does not permit accurate 

 direct comparison of on-tree injury with packout injury, the 

 substantial number of orchard blocks and apples sampled by each 

 method may be suggestive. 



The packout survey of 1980 fruit showed a total of 0.63% of 

 the fruit culled owing to insect injury, or about 15% as much as 

 the average of 3.9% insect injury from 1980 on-tree surveys in 

 IPM and check blocks combined. In the packout survey, the most 

 injurious insects, in decreasing order of importance, were tarnished 

 plant bug (0.23%), San Jose scale (0.21%), plum curculio (0.10%), 

 and European apple sawfly (0.07%). Together these 4 pests accounted 

 for 97% of all insect -culled fruit at the packing shed. These were 

 the same 4 pests found to be the most injurious in the on-tree sur- 

 vey. Apple maggot egglaying stings, difficult to see with the 

 unaided eye but indicative of probable infestation by larvae in 

 the fruit flesh, were very rarely detected in the packing shed, 

 even though this insect caused injury to an average of 0.12% of 

 tree-sampled fruit in 1980. 



Together, these findings indicte that among insects which dir- 

 ectly attack apple fruit, Massachusetts researchers, extension per- 

 sonnel, and fruit gorwers should be concerned primarily with the 

 aforementioned 5 species. For the past several years, we and/or 

 Drs. R.W. Weires and W.H. Reissig of New York have been conducting 

 research on improved ways of monitoring and controlling plant bug, 

 scale, curculio, sawfly, and apple maggot. We hope that continued 

 research progress will result in decrease of future injury from 

 these pests. 



