Spotted wing Drosophila numbers building rapidly in southwest Michigan

An unpleasant surprise is building for Michigan small fruit growers as spotted wing Drosophila trap counts are increasing.

I have received a couple of phone calls and texts indicating that people who are trapping for spotted wing Drosophila are catching increased numbers and at new sites. MSU Department of Entomology’s Rufus Isaacs’ crew is finding females in yeast baited traps in most of their trapping locations in Van Buren and Berrien counties. These flies are already being caught in increasing numbers in Allegan and Ottawa counties. This indicates to me that this pest is emerging across a wide area in southwest Michigan. It is emerging much earlier (two months) and in greater numbers than last year.

I repeat what I said the Tuesday, June 26, fruit crop regional report: If you are not trapping for this pest, DO NOT assume that you don’t have this pest. Assume that you DO!

Blueberry, raspberry and blackberry fruit become attractive to this pest as they color and ripen. The females mate soon after emergence and begin laying eggs in the fruit immediately. Adult flies live for three to six weeks, females lay over 300 eggs and the generation time is two to three weeks. This pest has the ability to emerge and infest all the ripen fruit in a field in a few weeks.

For more information, see the Blueberry Insect Scouting Report for June 18-24, 2012.

See the MSU IPM Spotted Wing Drosophila page for more information. Recommendations for control in Michigan blueberries was one of the handouts at the preharvest blueberry meetings in Van Buren and Ottawa counties.

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