Spotted Wing Drosophila Alert and Berry Notes — August 25, 2023

David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist, Phil Fanning, Assistant Professor of Agricultural Entomology, Christina Howard, Maine New Farmer Project Manager

Spotted Wing Drosophila on Raspberry
SWD on Raspberry; photo by David Handley.

Spotted Wing Drosophila:

We were unable to collect samples from our traps last week, due to staffing shortages. So, the numbers collected this week reflect two weeks’ worth of drosophila. We have divided the counts by two in the table to provide a crude weekly average. These averages indicate that the numbers of spotted wing drosophila caught in our traps have been rising in all locations. At all sites, numbers are over control thresholds, so regular sprays are recommended to protect ripening fruit.

At this point, a 5-7 day schedule of sprays may be needed to minimize fruit infestation in fields.

Remember that good sanitation can help reduce spotted wing drosophila numbers in a field. Pick fruit frequently; do not allow fruit to get over ripe. Keep rotten fruit off of the plants and the ground as much as possible and open up the planting to improve air and light penetration by trellising hanging canes and branches, and removing small lower branches that provide shade and humidity favored by these insects.

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

Spotted Wing Drosophila Trap Catch
Spotted Wing Drosophila Trap Catch, photo by Christina Howard

Other IPM Web Pages
Michigan State University Spotted Wing Drosophila
Penn State University Spotted Wing Drosophila Overview
University of New Hampshire SWD Weekly IPM Reports

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm
P.O. Box 179
Monmouth, ME 04259

UMaine Extension Diagnostic Research Lab
Pest Management Unit
17 Godfrey Drive
Orono, ME 04473

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Weekly Spotted Wing Drosophila Trap Captures

Town Spotted Wing Drosophila weekly trap catch 8/4/23 Spotted Wing Drosophila weekly trap catch 8/11/23 Spotted Wing Drosophila trap catch from 8/14/23 – 8/25/2023 Average trap catch for the past two weeks
Wells 22 166 600 300
Sanford 3 106 228 114
Limington 2 19 104 52
New Gloucester 214 280 840 420
Mechanic Falls 20 34 976 488
Bowdoinham 42 138 624 312
Monmouth (unsprayed plot) 43 114 1,408 704
Fayette 23 103 624 312
Wayne 8 1,012 506