Spotted Wing Drosophila Update: September 23, 2022
David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist, Phil Fanning, Assistant Professor of Agricultural Entomology, Christina Howard, New Farmers Program Manager
Spotted wing drosophila fly counts have been remarkably stable for the past few weeks at most sites, but the numbers are still fairly high and pose a threat to any late ripening fruit at this time. Counts are lower in locations where a tight spray schedule is being followed. We expect that fly numbers will remain high as long as food is available, and the weather conditions are favorable.
A 5-7-day spray schedule is recommended on all soft-fruited crops, including fall raspberries, blackberries, and day-neutral strawberries to prevent infestation by spotted wing drosophila larvae. Sprays should continue as long as flies are present and there is still fruit to harvest.
Once harvest starts it can be difficult to keep berry fields clean of over-ripe and rotten fruit, but field sanitation has been shown to significantly reduce drosophila numbers, so it pays to keep waste fruit off of the ground as much as possible to reduce food and egg-laying sites.
Other IPM Web Pages
Michigan State University: http://www.canr.msu.edu/ipm/invasive_species/spotted_wing_drosophila/
Penn State University: https://extension.psu.edu/spotted-wing-drosophila-part-1-overview-and-identification
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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The University of Maine is an equal opportunity/affirmative action institution.
| Town | Spotted Wing Drosophila weekly trap catch 9/9/22 | Spotted Wing Drosophila weekly trap catch 9/16/22 | Spotted Wing Drosophila weekly trap catch 9/23/22 |
| Wells | 1184 | 270 | 214 |
| Limerick | 202 | 34 | 13 |
| New Gloucester | 577 | 331 | 227 |
| Bowdoinham | 86 | 224 | 292 |
| Mechanic Falls | 992 | 623 | 1,208 |
| Monmouth* | 1032 | 3,088 | 1,320 |
| Wayne | 832 | 622 | 721 |
Weekly spotted wing drosophila trap captures.
*Unsprayed plot