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ALTERNATE vs. EVERY MIDDLE SPRAYING FOR APPLE PESTS IN 1978 



R. J. Prokopy, K. I. Hauschild, W. J. Manning, and T. R. Bardinelli 

 Departments of Entomology and Plant Pathology 



Earlier, we reported our 1977 findings on the comparative 

 effectiveness of alternate middle vs. every middle spray treat- 

 ments in 3 commercial apple orchards (See Fruit Notes 43 (3): 15-19). 

 Here, we report on our 1978 findings in 4 commercial orchards. 



The alternate middle treatment involves spraying alternate 

 halves of each tree on alternate spray dates instead of both halves 

 on all spray dates. For example, in applying the first cover spray, 

 the sprayer would be driven up the middle between tree rows A and 

 B and return down the middle between rows C and D, skipping the 

 middle between rows B and C. For the second cover spray, the sprayer 

 would be driven up the middle between rows B and C, down the middle 

 between rows D and E, and so forth. If this pattern were followed 

 with every spray application, it would save 50% of the spray material 

 costs . 



Each of our 4 test blocks was divided into 2 plots of 2-6 acres 

 each. One plot received the alternate middle program on each spray 

 date from pink (or petal fall) through last cover. The other received 

 the every middle program. Each grower used an air blast sprayer 

 at 4X. He followed his normal spray schedule, and used his own 

 selection of pesticides. Except in one block, all trees were full 

 grown - some on M7 rootstock, others on standard. The centers of 

 the trees were fairly well pruned in all blocks. 



To determine the extent of insect pest pressure, we hung traps 

 in each plot for monitoring tarnished plant bug, European apple saw- 

 fly, apple maggot, codling moth, redbanded leafroller, and oblique 

 banded leafroller adults (see Fruit Notes 44 (2): 1-2 for information 

 on construction of these traps). We caught the following average 

 numbers per trap: 



Pest Every middle plots Alternate middle plots 



Plant Bug 5.8 3.3 



Sawfly 1.3 2.5 



Apple maggot 2.3 0.8 



Codling moth 33.0 39.0 



Redbanded 50,8 58.3 



Oblique banded 2.3 1.8 



These results show that pest pressure from tarnished plant bug, 

 apple maggot, and oblique banded leafroller was greater in the every 

 middle plots, while pressure from sawfly, codling moth, and redbanded 

 leafroller was greater in the alternate middle plots. 



