-15- 



TABLE 3. Major Pest Species and Average Injury Levels^. Numbers 



in Parentheses Indicate Relative Ranking o£ Injury Level 



Pest IPM Orchards (8) Check Orchards (8) 



Tarnished Plant Bug 1.60% (1) 



European Apple Sawfly 0.68% (2) 



Plum Curculio 0.17% (3) 



Apple Maggot Fly 0.13% (4) 



San Jose Scale 0.03% (5) 



Codling Moth 0.01% (6) 



Leafrollers 0.01% (7) 



Green Fruitworm (8) 



Other 0.01% 



Based on on-tree surveys of 2,000 fruit per orchard (or orchard 

 block) at harvest (100 fruit on each of 20 trees) . 



The mite results in our IPM orchards were also encouraging. Our 

 8 IPM orchards averaged 1.2 miticide applications as compared with an 

 average of 1.6 applications in the 8 check orchards, and at the same 

 time had slightly more predator mites (Table 4) . We attribute the 

 slightly increased number of predator mites to selective use of 

 pesticides in the IPM orchards. (We asked growers not to use chemi- 

 cals that had previously been shown to be toxic to mite predators 

 [ Fruit Notes 43(5)]). In Orchard A (Table 5), which had a high num- 

 ber of predator mites (both A^ fallacis and yellow mites) , no miticide 

 application was needed this year. In Orchard B, in which an herbicide 

 shown to be toxic to A. fallacis was used, 3 miticide applications 

 were needed. As the eTfects of selective use of pesticides non-toxic 

 to predator mites take hold in IPM orchards in future years, we expect 

 increasing predator buildup and gradually decreasing need for miticide 

 application. 



TABLE 4. Summary of 1978 IPM and Check Orchard Mite Results 



