blocks and 0.2% in the first-stage blocks had AMF 

 damage. In 1989, 0.3% of the apples in both first- and 

 second-stage blocks showed AMF injury (Table 1). 

 Separate trials completed in 1989 indicated that a 

 maximum number of fly captures was achieved 

 when 2 vials of butyl hexanoate were placed 12 

 inches from the trap [Fruit Notes 54(4):18-19]. 



We were most encouraged by the results 

 achieved in 1988 and 1989. The only drawback to the 

 AMF traps is the cost and inconvenience involved in 

 coating them with sticky, hanging them in late June 

 each year, and cleaning them at least twice each 

 season. One method which might reduce these costs 

 is use of pesticide-coated spheres, an option which 

 we continue to explore [Fruit Notes 55(2): 17-20]. A 

 second method would be to decrease the number of 

 traps hung in each block. We hoped that using 2 

 vials of butyl hexanoate would increase fly captures 

 per trap and thus reduce the number of traps needed 

 for effective control. 



In 1990, we hung each trap using 2 vials of butyl 

 hexanoate and reduced the number of traps in some 

 blocks. In 1 of the original 6 second-stage blocks, we 

 hung 60 traps at a distance of 5 yards around the 

 perimeter of the block. In another of the original 6 

 blocks, we positioned 30 traps 10 yards apart. In 2 

 other original blocks, we hung 15 traps 20 yards 

 apart. We also placed 8 traps 40 yards apart in 5 

 blocks which had been managed using transitional 

 second-stage IPM methods from 1987 through 1989 

 [Fruit Notes 55(1):9-12]. During that time, the 

 border rows of the 6 blocks had been treated every 

 three weeks in July and August with Imidan™ or 

 Guthion™ against AMF. The interior of the blocks 

 received no insecticide or miticide after early June. 



Table 1 summarizes results of all 4 years of study 

 of the use of AMF traps in these orchards. Effective 



control was achieved only when the traps were hung 

 at distances of 5 yards apart. Over 3 years (1988-90), 

 AMF injury in second-stage blocks where traps were 

 placed 5 yards apart, averaged 0.7%. In adjacent 

 first-stage IPM blocks, AMF injury averaged 0.4%. 

 In two years of trials (1987, 1990) of perimeter traps 

 placed 10 yards apart, AMF injury averaged 3. 1%. 

 In adjacent first-stage blocks, AMF injury averaged 

 0.4%. When traps were hung 20 yards apart in 1990, 

 injury was 2.7% in the second-stage blocks vs. 1.0% 

 in the first-stage blocks. In the 5 blocks which had 

 traps 40 yards apart in 1990, injury averaged 2.9% 

 vs. 0.1% in the adjacent first-stage blocks. 



Our results suggest that using additional butyl 

 hexanoate will not increase fly captures per trap 

 sufficiently to allow a reduction in the distance 

 between traps. In fact, we believe that the additional 

 apple scent might have attracted greater numbers of 

 flies to some orchards. Placing traps 5 yards apart, 

 however, continues to provide control comparable to 

 the use of first-stage IPM methods in small blocks. 

 In 1991, we plan to test the effectiveness of AMF 

 traps positioned with one vial of butyl hexanoate 5 

 yards apart around the perimeter of larger, 5 to 10 

 acre blocks. 



Acknowledgements 



We thank the Northeast Regional Project on 

 Integrated Management of Apple Pests (NE 156) 

 and the Northeast Regional Low-Input Sustainable 

 Agricultural Project for supporting this work. We 

 also thank the participating growers: Bill Broder- 

 ick, Bruce Carlson, Dave Chandler, Dave Cheney, 

 Tony Lincoln, Dave Lynch, Harvey and Marvin 

 Peck, Wayne and Jesse Rice, Bill Rose, Tony Rossi, 

 Steve Smedberg, and Maurice Tougas. 



Fruit Notes, Winter, 1991 



19 



