12 



MONITORING AND CONTROL OF APPLE BLOTCH LEAFMINER: 



AN UPDATE 



Thomas Green, Susan Butkewich, William Coli, 

 Kathleen Leahy, and Ronald Prokopy 



Department of Entomology 

 University of Massachusetts 



and 



Glenn Morin and Roberta Spitko 

 New England Fruit Consultants 



In previous issues of Fruit Notes, we reported on the behavior of apple 

 blotch leafminer (ABLM) moths [49(3):19-22] and on the use of red visual traps 

 to monitor this pest [48(2):ll-14]. During the 1986 season, we conducted 

 experiments to improve both monitoring and control of ABLM, in cooperation 

 with a number of apple growers.^ 



During the 1985 and 1986 seasons, many growers successfully used visual 

 traps hung horizontally in the tree canopy to determine the need for a pre- 

 bloom insecticide application for ABLM. In 13 of 14 orchards, where the traps 

 were used and no insecticide was applied for ARLM before bloom, the numbers 

 of moths captured on the traps accurately predicted the need for an insecticide 

 treatment. 



We have experienced two problems \i using this trap. First, in most 

 cases, moth captures have been too few at tight cluster to make a treatment 

 decision. Wh(>n using Thiodiin ^^ for ABLM control tnis decision must be rnade 

 at tight cluster or earlier. Secondly, after a rail ABLM on the horizontal 

 surface of the trap lose their distinctive wingscal? pattern, making it difficult 

 to distinguish ABLM from other captured insects. 



To correct both of these problems, we experimented with a new trap 

 position, tacking the trap vertically to the south side of tree trunks at knee 

 height. Results from our study of ABLlVI behavior indicated that the motJis 

 accumulate on the lower portion of the tree trunk during the day in early 

 spring, probably for warmth. 



Our results this past season (Table 1) suggested that traps in this position 

 captured more ABLM earlier in the spring than did traps in the canopy, 

 although this difference was not statistically significant. ABLM were also more 

 easily recognized on the traps in the new position, even after a rain. 



^The authors wish to express sincere appreciation to the following growers who 

 participated in this work: Richard Bargeron, Keith Bohne, Dana Clark, Ed 

 Roberts, and Mike and Tim Smith. Excellent technical assistance was provided 

 by Suong Nguyen and James Mussoni. 



