Cooperative Extension at Highmoor Farm

Spotted Wing Drosophila Alert: August 17, 2017

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

Spotted wing drosophila trap captures have increased significantly at most locations over the past two weeks. (See table below.) All of the trapping sites are catching numbers that will result in significant infestations of larvae in any ripening soft fruit, especially raspberries, blackberries, blueberries and day-neutral strawberries. Peaches, nectarines and plums may also be susceptible, especially if the fruit have any growth or stem cracks. At this point, a spray schedule of 5 to 7 days apart should be adequate to prevent fruit infestation.

Spotted wing drosophila (SWD) populations are likely to continue rising as more fruit, especially waste fruit becomes available to the flies. Continue to look for fruit flies hovering around fruit and symptoms of premature fruit decay. The flies favor shady, moist regions of the planting. Be sure your insecticide sprays penetrate the outer foliage to reach the interior of the plants. Harvest regularly and often to prevent the buildup of overripe fruit and remove all rotten or cull fruit from the field. Pruning out excessive vegetative growth that provides shade and cover for the flies can also help reduce infestations and improve spray penetration.

Other IPM Web Pages

• Michigan State University
• Penn State University
• University of New Hampshire

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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