Spotted Wing Drosophila Alert: October 10, 2017

Spotted Wing Drosophila Larvae in Elderberries
Spotted Wing Drosophila Larvae in Elderberries; 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 numbers increased significantly at some of the trapping sites this week, although there doesn’t seem to be a pattern to those increases geographically. (See table below.) Fly numbers at other locations remained relatively stable or had slight decreases. However, all sites are still well over the threshold for infestation if fruit are left untreated. We have had several calls over the past two weeks regarding late ripening fruit (strawberries and elderberries) being infested with larvae. Therefore, 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 It is also important to keep wounded and rotten fruit out of the field as much as possible. Allowing it to stay on the plant or on the ground will attract more flies and provide food and shelter for more eggs and larvae. With the long-term forecasts predicting continued warmer than normal temperatures, it is likely that spotted wing drosophila will continue to threaten late ripening berries.

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.

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 9/22/17 Spotted Wing Drosophila weekly trap catch 9/29/17 Spotted Wing Drosophila weekly trap catch 10/6/17
Wells 45 527 567
Limington 373 80 87
Limerick 174 799 1808
Cape Elizabeth 879 204 124
New Gloucester 341 259 209
Bowdoinham 264 746 563
Dresden 554 2064 4376
Freeport 359 111 133
Poland Spring 1866 2608 440
Mechanic Falls 113 51 55
Monmouth 63 1624 4696
Wales 104 450 343
Farmington 286 440 7568