-14- 



To determine the amount of fruit injury caused by these and 

 other insect and disease pests, we examined at harvest 100 fruits 

 per tree from 18 trees in each plot. To determine spider mite and 

 aphid abundance on leaves, we examined 45 leaves per tree on 6 

 trees in each plot every 3 weeks from April until harvest. The 



following were the results: 



Avg. % leaves 



infested with : Every middle plots Alternate middle plots 



1.5 



6.5 



0.71 



0.43 



0.04 



0.06 



0.14 















Total insect 1.50 1.38 



Apple scab 0.73 1.61 



Black rot 0.21 0.19 



Other diseases 0.23 0.20 



Total disease 1.17 2.00 



Grand total 2.67 3.38 



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

 1.50% of harvested fruits in the every middle plots vs. 1.38% in 

 the alternate middle plots was injured by insects. Thus, even with 

 slightly higher pest pressure from sawfly, codling moth, and oblique 

 banded leafroller, the alternate middle plots averaged slightly less 

 total insect injury to fruits. 



The results also show that an average of 1.17% of harvested 

 fruits in the every middle plots vs. 2.00% in the alternate middle 

 plots was injured by disease. This difference was due largely to 

 one incidence wherein a grower failed to apply a needed spray for 

 apple scab, and suffered 5.67% fruit scab in the alternate middle 

 plot vs. 2.83% in the every middle plot. This suggests that proper 

 timing of fungicide sprays is very important to the success of an 

 alternate middle program. 



