Invasive insects, like the gypsy moth, pose a serious threat to the economy and environment of Minnesota. Without treatment, a population can get out of control and defoliate large sections of forest.

Based on careful review, the MDA uses the bacterium Btk, formulated in the product Foray 48B, for gypsy moth control.

Will the product harm humans, other mammals, fish, birds, bees or other insects?

No, Btk is not toxic to humans, mammals, birds, fish, honeybees or many beneficial insects. Btk needs to be ingested (eaten) to be effective and that the toxic substance is only released under alkaline conditions present in the stomach of insects. This alkaline condition is not present in the stomachs of humans, mammals, birds, or fish which is why the Btk does not affect them.

Btk is so specific to only certain moths and butterflies that it is an approved control product for use by certified organic gardeners.

Will more treatments be necessary?

Minnesota first used Btk for gypsy moth in 1984. Since then, the state has treated over 40 sites. Only one area has needed to be retreated. Why was a retreatment needed? It is likely the original treatment area was too small to eradicate all the gypsy moths. The MDA strives to find the right balance when drawing treatment areas.

We do our very best to design our management blocks as small as possible yet large enough to avoid missing the population and having to conduct a second year of application. In addition, we want to treat the population as quickly as possible to avoid the population from expanding and thus resulting a much larger treatment area in following years.  

Will the product harm my vehicle, home, and other items outside?

The spray residue is not harmful to humans, animals or outdoor structures. The spray can be easily washed off. It will show more readily on dark colored vehicles and it can be washed off. If left in the sun for a few days without washing, the spray deposit on vehicles may have to be rehydrated in order to remove it. Take an old bath towel and soak it in sudsy water and drape it over the vehicle for a few minutes. This will help soften the spray deposit and it can be removed. More ‘elbow grease’ may be required if the spray deposit is left on the vehicle for several days.