Improving management of spongy moth in Minnesota

photograph of a spongy moth adult

Adult spongy moth

Image credit: "Male Gypsy Moth" by imarsman; CC BY-NC-ND 2.0



The spongy moth (Lymantria dispar dispar) is an invasive moth from Europe that feeds on over 300 species of trees and shrubs, predisposing the plants to death. Spongy moth has been in Minnesota since at least 2013. It is closely managed by the Minnesota Department of Agriculture (MDA). Treatments are typically aerial sprays of a microbial protein isolated from the kurstaki variant of Bacillus thuringiensis (Btk).

Over the past 15 years, Minnesota has relied on phenology models developed in other states to determine effective timing of treatment. This has posed issues for management and limited success of treatments, especially in northern areas of the state where L. dispar caterpillars emerge late in spring.

Btk is specific to Lepidoptera (butterflies and moths), however, potential non-target effects of Btk on Minnesota species have not been well documented. In addition, the recovery of non-target Lepidoptera species after Btk treatment is not well understood.

Research questions

  • What are the thermal requirements for L. dispar dispar in Minnesota populations in a lab and in the field?
  • What are the effects of Btk on non-target organisms, particularly Lepidoptera species?

Practical implications

The research will result in a phenology model based on local information that includes inputs such as climatic lake effects and spring cold temperature events. In addition, researchers will work to uncover any effects of Btk treatments on non-target organisms. The research outcomes will improve pest management strategies and enable communicators to provide scientific data to the public.

Research team

Brian Aukema | principal investigator


Lab or other website 


Collaborating organizations

Minnesota Department of Agriculture

Minnesota’s Spongy Moth Program Advisory Committee

Minnesota Department of Natural Resources

USDA Forest Service State & Private

USDA Animal Plant Health Inspection Service