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Spotted Wing Drosophila Update: September 11, 2015

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Click on photos to enlarge.

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

Male Spotted Wing Drosophila

Male Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

Spotted wing drosophila trap captures have been increasing in most locations over the past two weeks. We have been anticipating a substantial increase in fly numbers for some time, and this may be the start of it. Some of the trap count increases may be related to there being less fruit available as the season winds down, which makes our traps more attractive to the flies. However, we have been getting calls from growers that are now finding infested fruit, suggesting that the pressure on any fruit remaining is high. Growers who still have berries to harvest should be able to manage drosophila with a five to seven day spray schedule of an appropriate insecticide. (See the New England Small Fruit Management Guide for more information and details.) Over the past two seasons, we have not seen drosophila numbers decline until after several hard frosts in November. However, growers should stop spraying once harvest is complete. Continuing to spray after harvest will not have a significant impact on next year’s drosophila populations.

Town Spotted Wing Drosophila weekly trap catch 9/4/15 Spotted Wing Drosophila weekly trap catch 9/11/15
Limington 228 89
Limerick 23 217
Wells 35 69
Cape Elizabeth 399 1042
Bowdoinham 90 **
Dresden 58 96
Nobleboro 111 **
Buxton 127 728
Livermore Falls 10 51
Mechanic Falls 11 55
Poland Spring 54 580
Monmouth 1200* 1217
Wales 108 221
Springvale 372 1217
Fayette 102 163

*Not sprayed
**Traps not collected yet

Spotted Wing Drosophila Larva in Blackberry

SWD Larvae in Blackberry, photo by David Handley

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

Other SWD sites include:
Michigan State University’s website,
Pennsylvania State University’s SWD website, and
University of New Hampshire’s SWD web page.

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

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