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Spraying every middle Spraying alternate middles 

 in orchard: in orchard: 



The results show that for all orchards combined, an average of 

 1.51 of the fruit in the every middle plots was injured by insects 

 vs. 2.51 fruit injury in the alternate middle plots. Compared with 

 1976, the 1977 results show 141 less fruit injury in the alternate 

 middle plots and 46% less in the every middle plots. Most of the 

 1977 difference between alternate and every middle plots was attri- 

 butable to Orchard B, where the presence of abandoned trees nearer 

 the alternate middle plot resulted in heavier insect pressure on 

 that plot. 



As in 1976, plant bugs caused the most fruit injury. Their 

 damage was slightly greater in the alternate than every middle 

 treatment. However, because plant bug damage on a ripe fruit 

 appears as a purely cosmetic injury, and does not affect the eating 

 quality of the fruit, most growers cull only about 50% of plant 

 bug injured fruits. The next most injurious insect was plum cur- 

 culio. It was the only fruit insect to cause greater injury in 

 the alternate middle than the every middle plot in each orchard. 

 Apple sawfly and green fruitworm caused slight injury, while no 

 fruits in any plots were found damaged by codling moth, apple maggot, 

 or redbanded leafroller. 



In contrast to 1976, aphids were, on the average, slightly 

 more abundant in the every middle than alternate middle plots. As 



