tide we have chosen to take a more conserva- 

 tive approach than the normal statistical prac- 

 tice, in that we consider differences to be truly 

 significant if the odds of them occurring by 

 chance are less than one in eight. In this way 

 we are more likely to identify differences be- 

 tween first- and second-level practices, and be 

 alerted to possible negative consequences. 



Results 



For Mcintosh, no fruit-damaging pest 

 caused significantly greater injtiry in second- 

 level than first-level blocks. Among foliar pests, 

 only potato leafhoppers were significantly more 

 abundant in second-level blocks (Tables 1 and 

 2). 



For Cortland, lesser appleworm, leafi-ollers, 

 white apple leafhoppers, rose leafhoppers, and 

 potato leafhoppers caused significantly greater 

 injury or were significantly more abundant in 

 second-level than first-level blocks (Tables 1 and 



2). 



For Delicious, apple maggot, codling moth, 

 leafrollers, and flyspeck caused significantly 

 greater injury and white apple leafhoppers, rose 

 leafhoppers and potato leafhoppers were signifi- 

 cantly more abundant in second-level than first- 

 level blocks (Tables 1 and 2). 



Conclusions 



We conclude that for Mcintosh, second-level 

 IPM practices achieve a level of fruit and foliar 

 pest control comparable to that achieved by 

 first-level IPM practices. The lone exception 

 was potato leafhoppers, whose adults annually 

 fly from sites of origin several hundred kilome- 

 ters to the south or west and invade orchards 

 in late June and July, well after residual activ- 

 ity of the last spray against plum curculio has 

 worn off We conclude that for Cortland, cur- 

 rent second-level IPM practices are short of pro- 

 viding needed levels of control of lesser 



Table 1 . Percent fniit injured by pests in samples taken at harvest in second-level and first-level IPM 

 blocks. Data are combined for 1992, 1993, and 1994*. 



♦Means in each couplet for each cultivar followed by a different letter are significantly different at 

 odds of 7: 1 . Two-hundred fruit of each cultivar (10 from each of 20 trees) in each type of block were 

 sampled each year at harvest. Number of blocks of each type containing each cultivar: Mcintosh (6 

 second-level, 6 first-level); Cortland (3 second-level, 2 first-level); Delicious (4 second-level, 3 first- 

 level). AMF=apple maggot; CM=codling moth; LAW=lesser appleworm; LR=leafrollers; SB=sooty 

 blotch; FS=nyspeck. 



12 



Fru/t Notes, Summer, 1995 



