Monitoring for spotted wing Drosophila (SWD) in fruit crops in east Michigan throughout the fall has detected this pest in six additional counties in the last two months. It was detected in one additional county earlier in September and in another east Michigan county last fall.
As of November 17, USDA-APHIS had confirmed that insects caught in the last few weeks in traps in Lapeer, Macomb, and Wayne counties were indeed SWD. Two weeks ago they confirmed SWD in Livingston County, the week before that in Oakland County, and the week before that in Monroe County. Most of these trap catches were at fruit farms.
On September 20, the USDA-APHIS confirmed a SWD catch from a fall red raspberry field in Washtenaw County. The September 2010 SWD catch was in Genesee County.
The total now stands at eight counties in east Michigan where SWD has been caught. Across the state, there is now a total of 22 counties where SWD has been detected.
Even though temperatures have dropped below freezing a few times over the last several weeks, growers continue to catch SWD in traps. Trap catch numbers have dropped off, however. Furthermore, in continued trapping for this insect throughout the fall, SWD has been found at many new fruit farms as well as other sites. So, not only have SWD been found in these new counties, but it has also been found in great abundance at many other farms within these eight counties.
Fruit growers need to learn all they can about this new pest this winter at meetings and conferences. This topic will be covered in several educational sessions at the Great Lakes Fruit, Vegetable and Farm Market Expo coming up Dec. 6-8 in Grand Rapids, MI. SWD identification and management will also be covered at several meetings being held across the state this winter and next spring and summer.
A great deal of other information and related resources on SWD are available at the MSU spotted wing Drosophila website.
Source: Bob Tritten and Rufus Isaacs, Michigan State University Extension and Department of Entomology