Spotted Wing Drosophila Alert: August 17, 2018

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

Captures of spotted wing drosophila (SWD) fruit flies in vinegar/yeast traps in raspberry and highbush blueberry plantings increased significantly at some locations this week, and is above threshold levels at most sites. Our highest counts of the season were found in raspberry plantings in Wales and Cape Elizabeth, with numbers now reaching into the thousands. (See table below.) Weather predictions suggest that conditions will continue to be good for SWD to continue increasing in fall raspberries, late blueberries, elderberries and fall strawberries. Growers with these crops should be putting on regular protective sprays if more than 4 flies have been captured in traps in a week. At this point a 5 to 7-day spray schedule should be adequate for most plantings. Make sure your sprayer is providing good coverage of the plant surface, especially in the lower part of the canopy.

Spotted Wing Drosophila Larvae in Elderberries
Spotted Wing Drosophila Larvae in Elderberries; photo by David Handley. Click on photo to enlarge.

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 8/3/18 Spotted Wing Drosophila weekly trap catch 8/10/18 Spotted Wing Drosophila weekly trap catch 8/17/18
Wells 0 0 5
Sanford 0 5 7
Limington 12 Trap down 23
Limerick 0 7 1
Buxton 0 11 58
Bowdoinham 2 34 152
Cape Elizabeth 1 18 1441
Dresden 5 49 10
Freeport 0 2 7
Poland Spring 0 2 7
Mechanic Falls 0 2 2
Monmouth 2 20 74
Readfield 12 17 51
Wales 2 216 4616
Farmington 1 0 3
Fayette 0 1 0
Wayne 0 0 1