and the joint federal/state apple IPM project for sup- 

 porting our work on second-stage apple IPM in 1989. 

 We also thank Kathleen Leahy, Dave Stanley, and 



Patti Powers for their assistance in sampling orchards, 

 and Roy Van Drieschefor determining leafminer para- 

 site levels. 



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Three Years of the Massachusetts 

 Second-stage Apple IPM Pilot Project: 

 Blocks Receiving Perimeter Row Sprays 



Margaret Christie, Cheryl Donovan, Katharine Rankin, and 

 Ronald Prokopy 



Department of Entomology, University of Massachusetts 



In the preceding article, we describe the rationale 

 and principles of second-stage apple IPM strategy and 

 tactics. We outline in that article two approaches to 

 achieving the second-stage IPM goal of greatly reduc- 

 ing or eliminating use of insecticide and miticide after 

 May. One principal distinction between the two ap- 

 proaches lies in the tactic used for managing apple 

 maggot flies: use of traps on perimeter apple trees to 

 intercept immigrating apple maggot flies before they 

 can penetrate the orchard interior versus spraying of 

 perimeter-row apple trees eveiy 3 weeks from June 

 through August to prevent flies from penetrating the 

 orchard. Here, we present a summary of 3 years of 

 implementation of the latter approach in 6 commercial 

 orchard test blocks. 



Methods Used 



The second-stage IPM test blocks averaged 2 acres 

 in size and were compared with adjacent blocks of 

 similar varietal composition and size, treated under 

 first-stage IPM practices. Each year, both types of 

 blocks were sprayed in essentially identical fashion 

 from April to early June. Thereafter, the first-stage 

 blocks received pesticide throughout the block when 

 pest monitoring information indicated a need for such, 

 while the second-stage blocks usually received insecti- 

 cide every 3 weeks on both sides of all perimeter apple 

 trees but no insecticide (or miticide) on the block 

 interior. In addition, all apple trees within 100 yards of 



the perimeter of each second-stage orchard block were 

 removed in May of 1987 to discourage immigration of 

 codling moths and summer leafrollers. 



Results 



Data in Table 1 show levels of pest captures on 

 monitoring traps and levels of pest injury to fruit. Over 

 the 3 years, 74% more apple maggot flies were captured 

 on nonbaited monitoring traps at the interior of sec- 

 ond-stage than first-stage blocks. This represents a 

 greater capture-level difference between first- and 

 second-stage blocks than where apple maggot intercep- 

 tion traps were employed on perimeter- row apple trees 

 (see preceding article). This result suggests that the 

 interception trap approach may be more effective than 

 the perimeter-row spray approach for intercepting 

 apple maggot flies. 



Apple maggot damage averaged about the same in 

 perimeter- row-sprayed and first-stage IPM blocks over 

 1987 and 1988, but in 1989 it was considerably greater 

 in the perimeter-row-sprayed blocks (1.2 versus 0.1%). 

 No codling moth or lesser appleworm injury to fruit 

 was found in any block in any year. Leafrollers caused 

 very little fruit damage in either type of block in 1987 

 and 1988 (0.1% or less) but in 1989 damage climbed to 

 0.3% in first-stage blocks (versus 0.1% in second-stage 

 blocks). All other insects remained at a very low level 

 throughout the study (0.2% damage or less). 



Data in Table 2 show levels of foliar pest mites and 



Fruit Notes, Winter, 1990 



