greater incidence of leafminer parasitoids and mite 

 predators (particularly Stigmaeiid yellow mites) in 

 the second-level blocks. 



Conclusions 



Our findings in this first year of applying second- 

 level IPM practices to blocks of scab-resistant culti- 

 vars indicate promise as well as some potential 

 problems for future application. Among arthropods, 

 the most promising aspectswere the success of pes- 

 ticide-treated spheres in controlling apple maggot 

 flies, the very low incidence of codling moth and 

 lesser appleworm, and the buildup of leafminer 

 parasitoids and mite predators (particularly yellow 

 mites). 



Among diseases, the most promising aspects 

 were (not surprisingly) the absence of apple scab and 



blossom end rot. The most 

 problematic aspects were 

 buildup of leafroller (ex- 

 clusively oblique-banded) 

 and flyspeck. 



From the perspective 

 of arthropod manage- 

 ment, use of pesticide- 

 treated spheres is the key 

 element of second-level 

 IPM. These spheres are 

 far simpler to prepare and 

 maintain than sticky 

 spheres. The only real 

 problem (aside from gain- 

 ing EPA registration for 

 use) involves the current 

 necessity of dipping the 

 sphere in aqueous sugar 

 solution after each rain- 

 fall. This is a rapid pro- 

 cess: 10 minutes to re- 

 move, dip and re-hang one 

 acre's worth of spheres. 

 But if it is not done almost 

 immediately after rainfall 

 has ended, there is no pro- 

 tection against apple mag- 

 got fly invasion. In 1993, 

 there were several un- 

 avoidable lapses of a day 

 or two in dipping spheres 

 after rainfall, possibly ac- 

 counting for the slightly 

 greater amount of maggot 

 injury in second-level 

 blocks. We need to find a new polymer capable of 

 releasing sucrose at a slow rate rather than losing all 

 of the sucrose during rainfall. 



With regard to leafrollers and flyspeck, virtually 

 all of the injury in 1993 was restricted to just one of 

 the three orchards. Another of the orchards had 

 almost all of the leafhoppers found; invading rose 

 leaflioppers at harvest were especially troublesome. 

 Perhaps the vegetation surrounding these orchards 

 harbored substantial "inocula" of these two pests. 

 This demands further study. 



Our experience in 1993 suggests much promise 

 for applications of low-labor second-level IPM prac- 

 tices in scab-resistant blocks. If we can keep sucrose 

 on pesticide-treated spheres during rainfall and 

 control flyspeck, leafroller, and leafhoppers using 

 habitat management and early-season fungicides, 

 then foliar pests such as mites and leafminer might 



Fruit Notes, Winter, 1994 



