Asian fruit fly – a game changer for berry growers

Last fall I wrote an article about a pest that could be the next true game changer.  Since many gardeners grow a lot of fruit, I wrote about the Spotted Wing Drosophila.  We know it’s getting closer to our area.  Tom Webb, food and ag reporter for the Pioneer Press, wrote an article about this insect July 17, and Bill McAuliffe, a weather and climate staff reporter for the Minneapolis Star Tribune, wrote about the same insect July 18.

The Spotted Wing Drosophila is an Asian fruit fly that arrived in the U.S. only five years ago, and it wiped out some raspberry crops in Minnesota last year. Now researchers are trying to prepare for this fall’s harvest.  The Spotted Wing Drosophila (SWD for short) attacks raspberries, grapes, blueberries, strawberries and cherries.  The fly lays its eggs inside the fruit.  The eggs hatch into maggots that make the fruit mushy.  Although there is no health issue to humans, the quality of the fruit is certainly affected.

In Tom Webb’s article he reported that officials are urging berry and grape growers to check for the pest and take action, but they concede that they still have a lot to learn about the SWD.  For now, the key is in detecting the problem early.  Most berry growers in Minnesota have not had to use insecticides, but Bill Hutchinson, a U of M entomologist, wrote, “This pest could be a true game changer for the berry industry.”  Using insecticides can mean salvaging the crop, but it’s not really a welcome prospect for businesses like the pick-your-own farms with people popping ripe berries in their mouths while picking.

State and University of Minnnesota officials offer a three-pronged effort to fight the infestation:  First, berry patch owners should set up monitoring traps.  Instructions are available on line at

http://www.vegedge.umn.edu/SWD/SWD.html.  Next, overripe fruit should be disposed because this is most attractive to the SWD.  Finally, insecticides can control the pest.  For details on insecticide treatment, call the State Department of Agriculture at 888-545-6684, or email the Department of Natural Resources at Arrest.the.Pest@state.mn.us

Tom Webb can be reached at 651-228-5428.

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