SPOTTED WING DROSOPHILA UPDATE: August 14, 2020
SPOTTED WING DROSOPHILA UPDATE: AUGUST 14, 2020
Click on photos to enlarge.
David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist, Christina Howard, Produce Safety Professional
Spotted wing drosophila (SWD) fruit fly numbers increased significantly at all but one of our monitoring sites this week, likely the result of the recent tropical storm and the increased availability of overripe fruit. Trap counts remain at levels well above those damaging to ripening berry crops (see table below). A five to seven-day spray interval is recommended for ripening berry fields to prevent infestation of larvae in the fruit. This is very likely to remain the case for the remainder of the season, or at least until we have several killing frosts.
Although it can be difficult once harvest has begun, keeping the field free of waste fruit can significantly reduce drosophila numbers. Chill all fruit to 34 degrees F (or as close as possible) immediately after harvest to halt development of any eggs or larvae. If soft fruit and/or larvae are noticed despite a 7-day spray schedule, shifting to a 5 day spray schedule is recommended.
Rotate pesticide products used regularly to prevent the possible development of resistance. Current information on registered pesticides for managing SWD is available in the New England Small Fruit Management Guide. The online version is free and can be viewed here
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 Unit
P.O. Box 179 17 Godfrey Drive
Monmouth, ME 04259 Orono, ME 04473
Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.
The University of Maine is an equal opportunity/affirmative action institution.
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