-19- 



Uneven performance of repeated, early season endosulfan sprays 

 for STLM adult control, as well as an earlier than normal third 

 generation of STLM in some blocks, required unanticipated added use 

 of methomyl or oxamyl in IPM blocks. Insecticide use in IPM blocks 

 would likely have been lower had growers been advised to rely more 

 heavily on early season use of the latter two materials. 



Residual San Jose Scale problems in several blocks necessitated 

 frequent sprays aimed at this pest. Fortunately use of Penncap M 

 against scale also provided excellent apple maggot control. 



Previous Year IPM growers applied 34% fewer miticide sprays 

 compared to the check, while First Year IPM growers applied 10% 

 more such sprays. Difficulties with First Year grower sprayer 

 calibration, poor penetration of concentrate sprays into overly 

 thick tree canopies, and the reluctance of some of these growers to 

 utilize spot treatments for mites, probably account for this differ- 

 ence . 



No aphicides were used in check or IPM orchards in 1981, and 

 syrphid fly and cecidomyiid midge predators of aphids were abundant 

 in most blocks (Table 2). Predator numbers, combined with numerous 

 hard rainshowers in June and July, helped to keep fruit from accumu- 

 lating aphid honeydew. Endosulfan used for STLM control may have 

 resulted in a highly favorable prey/predator ratio, with an enhanced 

 likelihood of biological control. 



Dosage equivalents (DE) of insecticide and miticide use reflect- 

 ing pesticide application rates, showed patterns similar to those 

 for number of spray application trips. DE of insecticide used in 

 Previous Year and First Year IPM blocks were 11% and 26% less than 

 the check. DE of miticide used were 60% lower in Previous Year IPM 

 blocks compared to the checks, while First Year IPM blocks used 10% 

 fewer miticide dosage equivalents than the checks. 



Cost and Benefit Comparison - Table 4 summarizes our cost benefit 

 analysis of IPM vs. check blocks in 1981. Both Previous Year and 

 First Year IPM blocks realized substantial savings in insecticide 

 and miticide materials costs, as well as spray application costs, 

 compared to the checks. Due to somewhat higher fruit injury levels, 

 however, value of fruit loss due to insect injury was $25.26 and 

 $87.54/A higher than the checks in Previous Year and First Year IPM 

 blocks respectively. As a result, while Previous Year IPM blocks 

 experienced a net benefit from IPM of $40.18/A, First Year IPM blocks 

 experienced a net loss of $29.84/A. 



It should be emphasized that this analysis is intended to show 

 relative not absolute numerical or percentage differences, and that 

 the values therein are average ones. As such, they do not reflect 

 grower wholesale prices for spray materials, per acre yields higher 

 (or lower) than 550 bu/A. , nor fruit prices that may differ substan- 

 tially from those used in this analysis. 



