Spotted Wing Drosophila Update: September 9, 2022

Male Spotted Wing Drosophila
Male Spotted Wing Drosophila, photo by Michigan State University

Spotted Wing Drosophila Alert:  September 9, 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 continued to rise this week.  Trap counts have been very high at all locations, meaning there is a very high threat level for any ripening fruit remaining in berry fields. Growers should maintain a tight, regular (5-7 day) spray schedule to prevent larvae from infesting fruit. We anticipate continued growth of fly numbers in the coming days, threatening any unprotected berries in the field.


Spotted Wing Drosophila Larva in Blackberry
SWD Larvae in Blackberry, photo by David Handley

All soft-fruited crops, including fall raspberries, blackberries, and day-neutral strawberries should be sprayed to prevent infestation by spotted wing drosophila larvae. Growers should maintain a 5-7-day spray schedule as long as flies are present.


Keep berry fields clean of over-ripe and rotten fruit as much as possible.  Rotten fruit on the plants or on the ground will greatly increase the number of fruit flies present, by providing them with food and egg-laying sites.


Other IPM Web Pages
Michigan State University:

Penn State University:



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


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 8/26/22 Spotted Wing  Drosophila weekly trap catch 9/2/22 Spotted Wing  Drosophila weekly trap catch 9/9/22
Wells 26 647 1184
Limerick 26 20 202
New Gloucester 32 166 577
Bowdoinham 48 47 86
Mechanic Falls 179 249 992
Monmouth 412 1,519 1032
Wayne 53 799 832



Weekly spotted wing drosophila trap captures.