Spotted Wing Drosophila (SWD)

About the Spotted Wing Drosophila (SWD)

SWD is a vinegar gnat from China and Japan. It attacks ripe and ripening fruit of brambles (raspberry & blackberry), strawberry, blueberry, grape, cherry, plum and peach, plus many species of wild berries. We first discovered it in New Hampshire on September 6, 2011. 2012 was the first year that it was present for the entire growing season, and it caused $1.516 million in crop losses in NH that year. The insect looks similar to our other 39 species of drosophilids: tiny (2mm long…about 1/12 inch) flies attracted to the odor of fruits and/or vinegar and fermentation. It attacks ripe and ripening fruit, while our other drosophilids attack overripe or rotting fruit. The females lay eggs INSIDE ripening fruit, so if you do not monitor your vulnerable crops, they could be infested with larvae inside. 

If you wish to keep your fruit from becoming infested, it is critical to monitor the insect with traps. When the flies appear and your crop is ripe or ripening, an insecticide spray can prevent it from being infested.


Additional Information 


Pesticides for Spotted Wing Drosophila

Below are two lists of insecticides useful in the control of SWD, compiled by Mary Concklin (University of Connecticut). Please remember that these are intended to be useful guides; ALWAYS follow the label.

***Important note*** 

There are now two NH 24c labels (means they can only be used in NH) for Cheminova’s malathion 57% EC.  They allow a higher rate (but fewer applications/season), so it is more effective than the regular rate. The label for highbush blueberries is SLN NH-130002. The lowbush blueberry label is NH-130001.  Your pesticide dealer should be able to get the product and the special label.

Since this is a new pest, management options are somewhat limited, and are changing rapidly.

Important information for Growers

For regular updates about this pest, please subscribe to our newsletter or call the fruit pest hotline at (603) 862-3763 (updated weekly through the growing season).

Other Excellent SWD Resources

Michigan State University's SWD Site


Anna Boudreau Supports Extension

I Support Extension

Anna Boudreau
State Advisory Council Chair