US (MN): New invasive insect causing damage to vegetable crops

A new invasive insect has made its way to Minnesota and is now causing damage to certain vegetables and crops. Swede midge is a small fly that infests cruciferous crops such as broccoli, cabbage, or canola. The insect was first discovered in Minnesota in 2016 by the Minnesota Department of Agriculture (MDA) in community gardens in Ramsey and Hennepin counties. This year, the MDA has spotted damage to vegetables in these two counties.

“Swede midge has the potential to greatly impact Minnesota,” said Mark Abrahamson, Assistant Director of MDA’s Plant Protection Division. “Crop losses will impact home, community and market gardens, as well as the state’s canola growers.”

Swede midge, which is native to Europe and southwestern Asia, is widespread in areas of eastern Canada and the northeastern U.S. It has also been confirmed in Manitoba near the Minnesota border.

Although traps are available for monitoring this pest, the insect larvae may be causing damage to crops before adult Swede midge can be detected with traps. Currently, Integrated Pest Management (IPM) programs – a process to solve pest problems while minimizing risk to people and the environment – have had limited success with the insect in other states. According to Dr. Bill Hutchison, Extension Entomologist at the University of Minnesota, more intensive monitoring for the pest will be needed, as well as additional insecticide use.

"Discovery of this new pest in Minnesota continues to confirm a disturbing trend of new invasive species affecting the state's agriculture industry,” said Dr. Hutchison. “This trend is also likely facilitated by increased global trade, travel and warmer winters.”

The U of M Extension IPM Program will work closely with the MDA to begin adapting IPM strategies for the affected crops as soon as possible. Work will also continue in 2018 to confirm the extent of infestations.

“It is important to track where this insect is present and if damage is being seen so that growers have an opportunity to prepare,” said Abrahamson.

Anyone who suspects crop damage from Swede midge should contact the MDA’s Arrest the Pest line at 1-888-545-6684 or email: arrest.the.pest@state.mn.us.

Vegetable growers looking for information on management options can contact the University of Minnesota Extension Farm Information Line at 1-800-232-9077 or www.extension.umn.edu/agriculture/farm-information-line/, or the VegEdge IPM page at www.vegedge.umn.edu.