Cooperative Extension at Highmoor Farm

Spotted Wing Drosophila Update: August 28, 2020

SPOTTED WING DROSOPHILA UPDATE:  AUGUST 28, 2020

David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist, Christina Howard, Produce Safety Professional

Spotted wing drosophila (SWD) fruit fly numbers rose again at most of our monitoring sites this week. This is partly due to more availability of waste fruit in some plantings.

However, another factor may be that: as fields get picked out of berries, i.e. food becomes more scarce late in the season, our trap bait becomes more attractive, and better at catching the flies. Even if this is so, the numbers are still high above control thresholds and any fruit still on the plants needs to be protected. A five to seven-day spray interval is recommended for ripening berry fields to prevent infestation of larvae in the fruit.

Although it’s difficult as we get towards the end of the season, keeping the field free of waste fruit can help keep drosophila numbers down. Sort fruit at harvest and before putting in storage to remove any soft berries. All fruit should be chilled to 34 degrees Fahrenheit immediately after harvest to halt development of any eggs or larvae. 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

Penn State University

University of New Hampshire

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
207.933.2100                          1.800.287.0279

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