Spotted Wing Drosophila Alert: August 17, 2017

Insects in Spotted Wing Drosophila Trap
Insects in Spotted Wing Drosophila Trap, Male SWD Circled; photo by Kaytlin Woodman

Click on photos to enlarge.

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 Larvae in Raspberry
Spotted Wing Drosophila Larvae in Raspberry; photo by David Handley

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

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
Spotted Wing Drosophila weekly trap catch
Spotted Wing Drosophila weekly trap catch
Wells 12 11 41
Sanford 8 4 115
Limington 233 678 517
Limerick 19 25 159
Cape Elizabeth 65 786 830
Buxton 14 37 455
New Gloucester 780 1534 554
Bowdoinham 128 130 402
Dresden 47 111 130
Freeport 3 17 50
Poland Spring 22 10 96
Mechanic Falls 0 1 24
Monmouth 2 17 57
Wales 85 429
Farmington 123 272
Fayette 8 37 117