Pressure by pests in Wisconsin's major crops continued to be relatively low into early August, but the count of spotted wing drosophila infestations in raspberries and other fruits continues to mount, according to the latest edition of the Wisconsin Pest Bulletin issued weekly by the Department of Agriculture, Trade and Consumer Protection.
As of Aug. 5, there had been official confirmation of SWD flies and larvae in 14 Wisconsin counties encompassing all areas of the state — Rock to Washburn counties from south to north and Door to Vernon counties east to west. The first larvae were detected on June 22 this year.
Official confirmation of an infestation is accomplished by submitting a raspberry with the distinctive white larvae or a caught fly to a DATCP representative. In addition to the list of counties with an official confirmation, there are many other counties where no grower has submitted a sample of an infested raspberry, grape or aronia.
The WPB explained that the SWD is a threat to the ripening fruits because eggs hatch and become larvae just when the fruit is ready for harvest. To minimize the population buildup, the WPB advises growers to dispose of fruit that becomes overripe, drops or splits.
Preventive measures include frequent applications of insecticides before the egg laying has occurred and the placement of covered containers (with drilled holes of three-sixteenths inch) with a couple of inches of apple cider vinegar and a drop of unscented dish soap. Details are available from Extension Services in several states (Wisconsin, Michigan and Cornell in New York). Refer to spotted wing drosophila on online search engines.
Source - http://www.freshplaza.com
