Transitional Step Toward Second-Stage Integrated Management of Arthropod Pests of Apple in Massachusetts Orchards

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Abstract
The practice of integrated pest management (IPM) may occur at multiple levels and at more than one stage within a level. In managing arthropod pests of apple, we consider the first stage of the first level (first-stage IPM) to be the use of multiple integrated approaches for determining need and optimal timing of application of a single technique of pest control: sprays of toxic pesticide. We consider the second stage of the first level (second-stage IPM) to be fully integrated use of multiple techniques of pest control, including behavioral, cultural, biological, and pesticidal methods. As a transitional step to eventual use of all components of a second-stage IPM approach, we evaluated application of insecticide every 3 wk (beginning in early July) to apple trees at the perimeter of orchards as a substitute for use of interception traps for behavioral control of immigrating apple maggot flies, Rhagoletts pomonella (Walsh). Remaining second-stage IPM components were implemented, with the orchard interior free of insecticide and acaricide application after early June. Results over 3 yr (1987-1989) in six commercial orchard test blocks of about 1 ha each showed that fruit injury by apple maggot was about the same during the first 2 yr in test blocks as in nearby control blocks sprayed under grower-implemented first-stage IPM practices. In the third year, however, injury in the test blocks was significantly greater, reaching 1.2%. Fruit injury by Lepidoptera and other summer pests was very low in all blocks in all years (0–0.3%). Except for mites (which were not always effectively controlled in test blocks by predators), populations of other principal foliar pests were little different in test blocks compared with control blocks. Average annual costs of insecticide and acaricide applications were about 310 and 470 per hectare in test and control blocks, respectively. We conclude that restricting insecticide application to perimeter row apple trees after early June in Massachusetts is an effective transitional step toward eventual use of a full second-stage IPM approach against apple arthropod pests.