Be on the lookout for Spotted Wing Drosophila. UNH Extension entomologist Dr. Alan Eaton and Maine Board of Pesticide Control specialist Gary Fish are alerting Mainers of a new pest found in several Strafford County, NH, locations in the past few weeks.
Bramble fruit (such as raspberries), and ever-bearing strawberries are thought to be the most at risk, though peaches, late season blueberries and grapes are also highly susceptible. The insect also attacks tomatoes, particularly in high tunnel and greenhouse environments.
Spotted Wing Drosophila (SWD), Drosophila suzukii, is an exotic pest that is relatively new to the US. Many were found on a raspberry planting north of Nashua, NH on Sept. 6. A few were found on Sept. 7 attacking tomatoes grown in high tunnels in Strafford (east of Concord, NH). For further details on the NH discoveries, see http://extension.unh.edu/Agric/Agric.htm.
SWD is different from native vinegar gnats/fruit flies because it attacks sound, ripe fruit. It doesn’t need over-ripe, rotting food because the female has a serrated egg-laying apparatus (ovipositor) that can cut right through tough skin. Once larvae are inside the fruit, no chemical pesticide can reach and kill them. Those fruit are essentially unsuitable for consumption or sale. Therefore early detection is critical.
Check this website for factsheets that provide good information on how to monitor and what insecticides work and don’t work for SWD:
http://www.ipm.ucdavis.edu/EXOTIC/drosophila.html
If you have specimens that should be identified, please contact your local county Extension office (in York County, at 1-800-287-1535 in Springvale) where you may bring the insects, or see UMaine Extension’s Insect and Plant Disease Diagnostic Lab’s Insect Submission Instructions, and send the insects to:
UMaine Cooperative Extension,Pest Management Office
491 College Ave., Orono, ME 04473-1295