Integrating High-Density Orchards and Biointensive Integrated Pest Management Methods in Northeastern Apple Production

Integrating High-Density Orchards and Biointensive Integrated Pest Management Methods in Northeastern Apple Production

Summary

This study was the beginning of third-level apple integrated pest management (IPM) in Massachusetts. This phase aimed primarily at studying the influence of apple tree architecture, particularly tree size, on effectiveness of biologically based approaches to controlling four important apple pests—plum curculio, flyspeck, apple maggot and mites—in 48 blocks of apple trees across eight commercial orchards. Each block was approximately square: seven trees per row by seven rows. Of the 48 blocks, 16 were comprised of large, medium and small trees. Of the 16 blocks of each tree size, eight were under bio-based management to the maximum extent possible, and eight were under first-level IPM management.

Major advances were achieved in bio-intensive IPM of the four key pests. A model to predict flyspeck risk based on orchard border characteristics and inoculum observed on alternate hosts was developed and tested in 1999, modified, and tested again in 2000. While the model could predict flyspeck risk in 80 percent of the cases in 2000, the 20 percent error makes it unacceptable for general use. This research provided a firm foundation, and work will continue.

Apple maggot fly was managed successfully with baited spheres in third-level IPM blocks. The traps were most effective in blocks of small, densely planted trees. Each year sphere design, sphere placement, and performance of baits were improved. Many traps and odor attractants were tested on plum curculio, with promising results. Use of pyramid traps and clear Plexiglas panels were perfected. A new upright branch mimic trap showed promise in 2000. Limonene and other odor attractants showed potential for use in plum curculio traps. Predatory mites (T. pyri) were established in all third-level IPM blocks and were distributed furthest from release sites in blocks of small densely planted trees. By year three, beneficial mites had spread three trees up and down in rows and across three rows from the release sites. Where they were established, the control of pest mites was very effective.

Small trees had canopies that were generally warmer, drier, and more open to light and spray penetration, than larger trees in lower density plantings. These small trees were less susceptible to economic injury by summer diseases and could be managed with less summer fungicide. The increased warmth and light were also expected to increase fruit quality. By following a bio-intensive advanced IPM approach, a grower could harvest a crop of equal or better quality and yield than by following a chemically based first-level IPM approach. In this study, small trees had heavier fruit than large trees, and bio-intensive blocks (third level IPM) had higher yields than conventional (first level IPM) blocks.

Reported April 2001

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