Egg mass hatching of spongy moth. Credit: Sayesha Khanna
Background
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.
Project phases
Research project title: Developing tools to improve Btk applications against spongy moth in Minnesota
Taxa: Invertebrate
Species: Spongy moth (Lymantria dispar dispar)
Timeline: January 2023 to June 2026
Funding: $424,849
Research questions
- What are the thermal requirements for spongy moth in Minnesota populations in a lab and in the field?
- What are the effects of Btk on non-target organisms, particularly Lepidoptera species?
Research project title: Improving when and how Btk is applied against spongy moth
Taxa: Invertebrate
Species: Spongy moth (Lymantria dispar dispar)
Timeline: July 2026 to July 2027
Funding: $91,279.81
Research questions
- What are the non-target effects of Btk on skippers and butterflies of conservation interest?
- How does plant phenology differ from degree days in Minnesota in relation to predicting spongy moth egg mass hatches?
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.
Outcomes
This project began in January 2023 and is in progress for the next several years. Please check back at a later time for updates.
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Outreach
- UMN Department of Entomology Seminar Series, 2024
- Upper Midwest Invasive Species Conference, 2024
- USDA Interagency Research Forum on Invasive Species, 2025
- North Central Forest Pest Workshop, 2025