Spotted Wing Drosophila Alert: September 15, 2017

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

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

Trap captures for spotted wing drosophila increased in most locations this week, likely stimulated by some warmer weather from tropical fronts moving through Maine. Fly populations remain well over the tolerance level to prevent fruit infestation. (See table below.) Growers with any susceptible ripening fruit will need to continue protecting their crop against larval infestation. Regular, consistent spray coverage is needed to prevent fruit infestation. At this time, we continue to recommend a minimum spray interval of 5 to 7 days.

There is a possibility that any more tropical storm fronts moving into the region could further increase drosophila numbers. Harvest all ripe fruit regularly and remove any rotten or cull fruit from the field.

Insects in Spotted Wing Drosophila Trap
Insects in Spotted Wing Drosophila Trap, Male SWD Circled; photo by Kaytlin Woodman

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 1256 273 330
Limington 428 568 734
Limerick 237 326 1771
Cape Elizabeth 2968 1308
New Gloucester 272 383
Bowdoinham 1448 449 792
Dresden 103 666 1584
Freeport 56 164
Poland Spring 597 807 1145
Mechanic Falls 65 77 48
Monmouth 681 434 470
Wales 642 122 86
Farmington 1552 1728 1848