Spotted Wing Drosophila Alert

This announcement is also posted with color pictures on the Highmoor Farm Spotted Wing Drosophila web blog at, where you can subscribe to updates.

Spotted Wing Drosophila Alert:  7/21/2017

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

There has been an increase in spotted wing drosophila activity at most trapping sites this week (see table below). Reports from throughout the northeast suggest a similar trend. This is significantly earlier activity than we have seen in recent years, and some of the trap counts are already well above what we consider potentially damaging to ripening berry crops, especially raspberries and blueberries.  Research suggests that when 6 to 10 flies are caught in a yeast-baited trap in a week, larvae will start appearing in the fruit.


We expect that spotted wing drosophila populations (SWD) will continue to build rapidly in the coming weeks as more eggs are laid in the fruit that is now ripening. Growers should set out traps, if you haven’t already. Start protective sprays on any berries that have begun to ripen when more than four spotted wing drosophila flies are caught in a trap, or any larvae are noticed in the fruit. Look for fruit flies hovering around fruit and symptoms of premature fruit decay. Remember, the flies favor shady, moist regions of the planting.

You can find directions for making a home-made SWD monitoring trap on our blog. (See address below.) An effective commercial trap and bait is now available from Scentry.  The trap is reusable and the bait lasts 4-6weeks.  Cost for both is about $15 plus shipping, it is available from Great Lakes IPM Company (

For more information on identifying spotted wing drosophila and updates on populations around the state, visit our SWD blog at:

Other IPM Web Pages
Michigan State University:

Penn State University:

University of New Hampshire:


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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Town Spotted Wing  Drosophila weekly trap catch 7/6/17 Spotted Wing  Drosophila weekly trap catch 7/13/17 Spotted Wing  Drosophila weekly trap catch 7/20/17
Wells 19 8
Sanford 0 4 6
Limington 4 2 7
Limerick 1 3 4
Cape Elizabeth 19 21 37
Buxton 12 6 3
New Gloucester 3 30 298
Bowdoinham 2 10 28
Dresden 0 0 2
Freeport 2 0 4
Poland Spring 1 2 2
Mechanic Falls 14 5 0
Monmouth 2 4 5
Wales 110 121
Farmington 0 3 9
Fayette 6 3 5





Pam St. Peter
Administrative Specialist II
University of Maine Cooperative Extension
Maine Crop Insurance Education Program
Highmoor Farm
P.O. Box 179/52 US Route 202
Monmouth, ME  04259
Tel. 207.933.2100 X100
Fax 207.933.4647