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Fruit Growers Alert 7/26/13: Spotted Wing Drosophila Activity Spreading

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Fruit Growers Alert – July 26, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.


Spotted Wing Drosophila Trap

SWD Trap, photo by David Handley

Spotted wing drosophila (SWD) flies were captured in traps in Wells, Warren, Dresden, New Gloucester, Monmouth, Union and Lincolnville this week. These trap captures indicate that SWD has become active in more regions of the state. Most trap captures have been very low to date (1 to 3 flies), but some sites near the coast have seen higher numbers this week. A trap in Dresden caught seven flies. One trap in Warren caught 13 flies while another caught 84.  SWD populations are also rising in the other New England states this week, according to reports from Massachusetts, New Hampshire and Connecticut.

There is no valid threshold for spotted wing drosophila in berry fields. At this point we believe that if any SWD have been captured in your area and you have ripe or nearly ripe fruit in your fields, the crop should be protected with a recommended insecticide.

Male and Female Spotted Wing Drosophila Flies

Male (left) and Female (right) Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

Spotted wing drosophila poses the greatest threat to raspberries, blackberries, blueberries and other soft fruit that is beginning to ripen (elderberries, peaches nectarines, etc.). Products that provide good control of drosophila on berries include Delegate®, Brigade®, Bifenture®, Danitol®, Mustang Max®, malathion and Assail®. Research carried out at the Connecticut Agricultural Experiment Station suggests that adding table sugar to group 4A insecticides such as Assail®, may improve their effectiveness. The recommended rate would be 1-2 lb. sugar per 100 gallons of spray. Effectiveness of these products can range from three to seven days. Repeated applications throughout the harvest season will likely be required to prevent larvae from infesting the fruit. Please check product labels for rates, post-harvest intervals and safety precautions. Keeping the fields clean of over-ripe and rotten fruit can also help reduce the incidence of this insect.

For information on identifying spotted wing drosophila and making your own monitoring traps, visit the Michigan State University’s Spotted Wing Drosophila website. There is also a good fact sheet series on Management of Spotted Wing Drosophila from Penn State on their website.

Highmoor Farm Fruit and Vegetable Growers Field Day July 31, 2013
Join us for the Highmoor Farm Field Day and Summer Tour to be held on Wednesday, July 31, starting at 9:00 a.m. Please join us for the program, farm tours and lunch. For more information and to register online, visit the Field Day website.

David T. Handley
Vegetable & 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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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.

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