15 



pins. Thus, at present, we still suggest the standard procedures 

 of leader selection. This involves selection of the uppermost 

 shoot on the windward side of the newly-planted tree when shoot 

 growth is 6 to 8 inches in length. Shoots competing with the 

 selected leader should be rubbed or pruned off for a distance of 

 approximately 6 inches down the stem.. 



*************** 



ALTERNATE VS. EVERY MIDDLE SPRAYING FOR APPLE PESTS IN 1977 



R.J. Prokopy, R.G. Hislop, and K.I. Hauschild 

 Department of Entomology 

 and R.L. Christensen 

 Department of Agricultural and Food Economics 



Earlier, we reported our 1976 findings on the comparative 

 effectiveness of alternate vs. every middle spray treatments in 3 

 commercial orchards (see Fruit Notes 42(5):8-10). In this article, 

 we report on our 1977 findings , and include a cost-benefit treat- 

 ment comparison for one of the 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. 



In 1977, we compared alternate with every middle spray treat- 

 ments in the same 4-acre blocks in the same 3 orchards as in 1976. 

 Each block was divided into 2 plots : one receiving the alternate 

 middle program on each spray date from pink (or petal fall) through 

 last cover; the other receiving 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. All 

 trees were full grown - some on M. 7 rootstock, others on standard. 

 The centers of the trees were fairly well pruned in all blocks. 



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

 each plot for monitoring tarnished plant bug adults, codling moth 

 and redbanded leafroller adults, and apple maggot flies (see Fruit 

 Notes 41(1) : 3-4; 41(6) :6-9; and 43(2):10-14 for information on 

 construction of each trap type) . We caught the following average 

 numbers/trap in each plot: 



