Spotted Wing Drosophila Alert: September 1, 2017

Male Spotted Wing Drosophila
Male 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

Our trap captures for spotted wing drosophila continued to increase this week at nearly all locations. (See table below.) Growers with any susceptible ripening fruit will need to continue protecting against fly egg-laying and larval infestation. Only regular, consistent spray coverage will prevent fruit infestation. We recommend a minimum spray interval of 5 to 7 days.

While cooler evening temperatures slow fruit development, we have seen little impact on spotted wing drosophila activity, thus we expect populations to continue rising, until they are exposed to several hard frosts. Keep harvesting ripe fruit regularly and remove all rotten or cull fruit from the field.

Spotted Wing Drosophila Larva in Blackberry
SWD Larvae in Blackberry; 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

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.


Town Spotted Wing Drosophila weekly trap catch
Spotted Wing Drosophila weekly trap catch
Spotted Wing Drosophila weekly trap catch
Wells 41 387 1256
Sanford 115 93 143
Limington 517 842 428
Limerick 159 217 237
Cape Elizabeth 830 4320
New Gloucester 554 603
Bowdoinham 402 925 1448
Dresden 130 104 103
Freeport 50 40 56
Poland Spring 96 304 597
Mechanic Falls 24 16 65
Monmouth 57 415 681
Wales 1816 (2 weeks) 642
Farmington 1048 (2 weeks)