Spotted Wing Drosophila Alert: October 13, 2017

Spotted Wing Drosophila Damage in Elderberry Plant
Spotted Wing Drosophila Damage in Elderberry Plant; photo by David Handley

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

Spotted wing drosophila populations continue to be high but variable this week. While some locations saw decreases in the weekly trap catch, others had the highest numbers of the season. (See table below.) This variability can be due to a number of factors, including changing availability of food, ambient moisture, temperature, and insecticide applications. Despite the variation however, all sites were over the threshold for infestation if fruit were left untreated; and growers who still have ripening fruit should continue to protect their crop on a spray interval of 5 to 7 days to prevent fruit from becoming infested. Also, continue harvest regularly and often, and keep overripe and rotten fruit out of the field as much as possible. Long range weather forecasts suggest a warmer than normal stretch of days ahead. While this is great for extending the late berry season, it also means that spotted wing drosophila will likely continue to be a threat.

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

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

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 9/29/17 Spotted Wing Drosophila weekly trap catch 10/6/17 Spotted Wing Drosophila weekly trap catch 10/13/17
Wells 527 567 88
Limington 373 80 152
Limerick 174 799 187
Cape Elizabeth 879 204 750
New Gloucester 341 259 408
Bowdoinham 264 746 244
Dresden 554 2064 2816
Freeport 359 111 655
Poland Spring 1866 2608 294
Mechanic Falls 113 51 31
Monmouth 63 1624 1188
Wales 104 450 372
Farmington 286 440 5680