Spotted Wing Drosophila Update: 7/23/2021
Spotted Wing Drosophila Update: July 23, 2021
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David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist, Phil Fanning, Assistant Professor of Agricultural Entomology
While we continue to find spotted wing drosophila fruit flies in raspberry plantings and blueberry fields in Maine this week, the situation has not changed much since last week. Counts of flies in vinegar/yeast traps remain in the three to ten range, meaning that growers should consider protecting ripening fruit to protect against infestation. When six to ten flies are caught in a yeast-baited trap in a week, larvae will start appearing in the fruit. A seven-day spray interval should be adequate at this point, but if growers are seeing drosophila flies around ripening fruit during harvest, or have found larvae in the fruit, they should tighten the spray schedule to every five days. This was the situation at one raspberry field this week, as flies were readily visible while I was setting up a trap, and ripe fruit near the ground was soft and infested with larvae.
Expect spotted wing drosophila populations to increase in the coming weeks as more fruit becomes available. Set out traps, if you haven’t already, to monitor the flies. See last week’s SWD Alert for information on making and placing traps, and a list of currently registered insecticides for SWD.
For more information on identifying spotted wing drosophila (SWD) and updates on populations around the state, visit our SWD Blog
Other IPM Web Pages
Michigan State University
David T. Handley
Vegetable and Small Fruit Specialist
Highmoor Farm Pest Management Office
P.O. Box 179 17 Godfrey Dr.
Monmouth, ME 04259 Orono, ME 04473
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