Spotted Wing Drosophila Alert: August 24, 2017

Male and Female Spotted Wing Drosophila Flies
Male (left) and Female (right) Spotted Wing Drosophila; photo by Griffin Dill. Actual size: 2-3 mm.

David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist; Frank Drummond, Professor of Insect Ecology/Entomology

Spotted wing drosophila trap captures continue to increase as we move later into the season. (See table below.) Such high fly numbers will cause significant infestations of larvae in any ripening soft fruit, especially raspberries, blackberries, blueberries and day-neutral strawberries. Consistent spray coverage of susceptible crops is now necessary to prevent fruit infestation. We recommend a minimum spray interval of 5 to 7 days.

Populations are likely to continue rising as more food is available to the flies. Often it is not until we have experienced several hard frosts that we see populations start to decline. Harvest regularly and often to prevent the buildup of overripe fruit and remove all rotten or cull fruit from the field. Prune out excessive vegetative growth that provides shade and cover for the flies. This will also improve spray penetration.

Spotted Wing Drosophila Larvae in Blueberry
Spotted Wing Drosophila Larvae in Blueberry; photo by David Handley

For more information on identifying spotted wing drosophila and updates on populations around the state, visit our SWD blog.

Other IPM Web Pages

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm, P.O. Box 179, 52 US Route 202, Monmouth, ME 04259, 207.933.2100

UMaine Extension Diagnostic Research Lab, Pest Management Unit, 17 Godfrey Drive, Orono, ME 04473, 1.800.287.0279

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Town Spotted Wing Drosophila weekly trap catch
Spotted Wing Drosophila weekly trap catch
Spotted Wing Drosophila weekly trap catch
Wells 11 41 387
Sanford 4 115 93
Limington 678 517 842
Limerick 25 159 217
Cape Elizabeth 786 830 4320
Buxton 37 455 641
New Gloucester 1534 554 603
Bowdoinham 130 402 925
Dresden 111 130 104
Freeport 17 50 40
Poland Spring 10 96 304
Mechanic Falls 1 24 16
Monmouth 17 57 415
Wales 429 1816 (2 weeks)
Farmington 272 1048 (2 weeks)
Fayette 37 117 210