May 19, 2017

The Minnesota Department of Agriculture (MDA) is planning a final treatment for portions of Richfield and Minneapolis to a eradicate gypsy moth infestation detected last fall. Officials plan to conduct the treatments on Monday, May 22, starting as early as 5:30 a.m. This is dependent on weather conditions at the time.

In 2016, MDA’s trapping program found an infestation in the northwest corner of Richfield. To eradicate the moths before they spread, officials conduct two aerial applications of Bacillus thuringiensis var. kurstaki (Btk) over the same area. Two applications are needed because the product naturally breaks down in sunlight. The first application was conducted on Thursday, May 11.

Btk is a U.S. Environmental Protection Agency-approved bacterium with very low risk for humans or animals other than caterpillars. Btk is widely used within the organic gardening community. Over the years, MDA has eradicated gypsy moth infestations on thousands of acres across the state using this method. These efforts protect forest health, property values, and the state's tourism industry.

Gypsy moths are among America's most destructive tree pests, having caused millions of dollars in damage to Eastern forests. The moths are now threatening Minnesota. If present in large numbers, gypsy moth caterpillars can defoliate large sections of forest.

To help area citizens stay informed, the MDA has set up an Arrest the Pest Info Line at 1-888-545-MOTH. The info line will offer the latest details about treatment dates and times. MDA's website ( also has information about gypsy moths and control efforts. Finally, MDA offers the following tips to residents in the treatment area:

  • For the moth treatment to work, it must begin early in the morning. Monday’s treatment may begin as early as 5:30 a.m. Residents may be awakened on that day by the noise of the low-flying helicopter. MDA apologizes for any inconvenience;
  • The treatment product has no known health effects for humans, but to avoid it residents may wish to stay indoors during the treatment and keep windows closed for a half hour after application; and,
  • Any residue, which does not cause damage to outdoor items, can be removed soapy water.

Details of treatment area: 
The area runs from West 61st Street in Minneapolis on the north to West 67th Street in Richfield on the south, and Washburn Avenue South on the west to Logan Avenue South on the east. (SEE MAP) Details of the area can be found at


Media Contact
Allen Sommerfeld, MDA Communications