Good Fruit Grower

September 2013

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Optimizing Production Pest management requires precise tools O ver the years, fruit growers have traded in their shotgun-like pest control tools for more precise rifle-like tools and bullets capable of hitting moving targets with great accuracy. As they adopt these new weapons, they need to perfect their use of them. During the Eastern Apple Precision Orchard Management Summit held in Geneva, New York, last March, there was not much discussion about the "bullets"—the insect and disease control chemicals—except to say they are like bullets, not like pellets in a shotgun, and that growers need to fire precisely the right ones at precise times, using different bullets for different pests at different stages of development. Part of the discussion focused on the weapons—the sprayers that deliver the bullets into trees that are not the same as they once were. Small trees in high-density configurations are not the same as big trees with large canopies. Nor is there much room for error, for both environmental and cost-efficiency reasons. Most of the discussion focused on aiming—how do orchardists hit the targets and, more importantly, how do they know when the targets are there and vulnerable to being hit? Unlike bygone days when growers "kept covered" with by Richard Lehnert long-residual insecticides and fungicides applied on seven- to ten-day intervals— more often if it rained—growers have to find comfort even as they know they as less "covered." photo courtesy of cornell university PART VII: Growers fire up their computers before firing up their tractors. The system tracks " development of key insect pests and diseases using degree-day and infection-risk models." —Dr. Art Agnello 10 SEPTEMBER 2013 Good Fruit Grower Precise insect management In the damp, humid orchards of the eastern United States, growers face many challenges, says Cornell University entomologist Dr. Art Agnello, because there are so many pests. "Growers are attempting to turn to newer reduced-risk pesticides, but these are more expensive and require more precise timing and use patterns because of their different modes of action," he said. Eastern growers face five major insect pests—plum curculio, apple maggot, codling moth, oriental fruit moth, and obliquebanded leafroller. Then there are secondary pests—mites, scales, aphids—and cyclic pests that sometimes appear—potato leafhoppers, stink bugs, Japanese beetles. Then new ones come along, like spotted wing drosophila and brown marmorated stinkbug. Where once they could almost all be managed with repeated cover sprays of broad-spectrum insecticides, now they must be approached individually. As they try to improve the precision of the process, Agnello said, growers need to remember that the key pests drive the pest management program, just as they always have. Growers need to know precisely when they show up, when they reach a stage that is vulnerable to control, when they start posing a threat to the crop, and when they stop being a threat. The discovery that insects and diseases develop according to accumulated temperatures has allowed researchers to create models based on growing degree-day accumulations. "During the last several years, an interdisciplinary group of researchers at Cornell University has developed a Web-based, real-time, apple IPM decision support system that can deliver relevant, current information on weather data and pest populations to facilitate grower pest management decisions throughout the growing season," he said.

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