Table 6. Partial analysis of estimated cost (dollars) per acre per year of first-stage 

 versus second-stage IPM practices for insect and mite control (averaged over all 3 

 years). 



*Materials plus application costs. 



**Pro-ratcd over 10 years. 



***Includes initial cost of $80 (pro-rated over 10 years at $8/year) for purchase of 



traps, $2/year for tangletrap, $10/year for purchase of vials and attractive odor 



(both new each year), and $62/year for 10 hours of labor required to sticky-coat, 



emplace, clean (3 times), and remove the traps. 



emplacing, and cleaning the apple maggot traps, sec- 

 ond-stage IPM was no more expensive than first-stage 

 IPM. Replacement of sticky spheres by pesticide- 

 treated spheres should lower the cost of future second- 

 stage IPM application dramatically. 



Conclusions 



Overall, we are extremely encouraged by the re- 

 sults of 3 years of implementation of second-stage IPM 

 practices involving use of interception traps against 

 apple maggot flies in the 6 commercial apple orchard 

 test blocks. Fruit injury by apple maggot and codling 

 moth has stabilized at a veiy low level. Beneficial 

 predators and parasitoids have begun to flourish and to 

 provide good control of major foliar pests (although, 

 leafhoppers may be an exception). Fruit quality at 

 harvest, as evidenced by our systematic sampling of 

 injury levels and asjudgedby cooperating growers, has 

 been excellent. Second-stage blocks received only a bit 

 more than half as many insecticide sprays and a tenth 

 as many miticide sprays as first-stage blocks. Second- 

 stage practices were no more expensive than first-stage 

 practices, even under the labor-intensive effort associ- 

 ated with using sticky apple maggot traps. 



We believe, however, 

 that there are 3 key areas to 

 be addressed before we can 

 recommend confidently 

 second-stage IPM practices 

 for widespread use. The 

 first is development of a 

 substitute for sticky (which 

 is too messy to handle on a 

 large scale) as the agent 

 controlling apple maggot 

 flies alighting on apple- 

 odor-baited red sphere 

 traps. Our progress in 

 developing such a substi- 

 tute (pesticide treated 

 spheres) will be reported in 

 a separate Fruit Notes ar- 

 ticle. The second is mainte- 

 nance of summer leaf- 

 rollers and lesser apple- 

 worms at a low level in sec- 

 ond-stage IPM orchards. 

 For this purpose, we need 

 further work on the poten- 

 tial value of using Dipel or 

 Dimilin in early season 

 sprays, and on employing 

 mating disruption phero- 

 mone. The third is picking up all drops shortly after 

 harvest. If drops were not removed before decay set in, 

 larvae of apple maggot, lesser appleworm, codling 

 moth and some leafrollers would have the opportunity 

 to remain and develop to overwintering maturity. 

 There would be within-orchard buildup of these pests, 

 threatening next year's crop. This buildup would 

 negate the value of attempting to manage these pests 

 by preventing their immigration into the orchard. The 

 loss of Alar™ and the consequent greater number of 

 apple drops makes this job more difficult. 



If the EPA would approve general use of an odor- 

 baited, pesticide-treated-sphere system of controlling 

 apple maggot flies, if apple drops were faithfully picked 

 up shortly after harvest, and if we could contain dam- 

 age by summer leafrollers and lesser appleworms at a 

 low level, then growers should be able to employ sec- 

 ond-stage IPM practices with high confidence. Grow- 

 ers and the public alike would benefit from a healthier 

 orchard environment. 



Acknowledgements 



We thank the Massachusetts Society for the Pro- 

 motion of Agriculture, the Northeast Regional Project 

 on Integrated Management of Apple Pests (NE-156), 



8 



Fruit Notes, Winter, 1990 



