Researchers say the findings will support new forecasting tools to help US potato growers better anticipate early season beetle pressure as climate conditions continue to shift.
A long term research project from Michigan State University (MSU) and the University of Wisconsin is offering new insight into what drives Colorado potato beetle outbreaks, giving US potato growers a clearer picture of how weather patterns and environmental conditions shape one of the industry’s most persistent pest challenges.
The Colorado potato beetle remains one of the most destructive insect pests in potato production because of its extraordinary ability to develop resistance to insecticides.
Over decades, the beetle has adapted to nearly every major chemical class used against it, leaving growers with fewer effective tools each season. Both larvae and adults feed aggressively on potato foliage, and heavy infestations can defoliate plants quickly, reducing yields if not controlled early.
Another reason the beetle is so difficult to manage is its resilience. It overwinters successfully in soil, even in cold northern climates, and warming temperatures allow it to reproduce faster and complete more generations per year.
The pest is widespread across nearly all major potato‑growing regions. In the United States, it is a persistent problem in the Great Lakes, Northeast, Midwest, High Plains, Mountain West, and Pacific Northwest. In Canada, it affects production in Ontario, Quebec, Manitoba, Alberta, and the Maritimes. The beetle has also spread beyond North America into Europe and parts of Asia, making it a global agricultural concern.
The team analyzed 16 years of data to determine which factors most strongly influence beetle abundance. While heat remains the dominant driver of beetle development, the study found that precipitation, air saturation, and soil temperature during overwintering periods also play important roles in determining how populations rise and fall each year.
According to the researchers, extremely hot conditions tend to increase beetle numbers, while very cold conditions do not reduce them to the same degree—an indication that the pest may thrive under more extreme future climates.
The project was led by Abigail L. Cohen of MSU’s Department of Entomology, working with Benjamin Bradford and Russell Groves from the University of Wisconsin and MSU entomologist Zsofia Szendrei.
The work is funded by a USDA SCRI grant led by Szendrei. Their goal is to better understand what environmental factors trigger Colorado potato beetle outbreaks, a critical step in protecting yields and reducing losses for potato producers across the country.
To build a more complete picture, the researchers used two types of models—one to predict beetle numbers and another to explain why those numbers change over time. The results show that relying on heat alone is not enough to anticipate population spikes, especially as climate variability increases.
“This research grew out of a larger effort to decrease our reliance on neonicotinoid insecticides in potato production and combine new pest management programs with pest prediction and decision making tools,” Cohen said.
The team is now working to develop forecasting models that can help growers anticipate when beetles are likely to appear at the start of the growing season and how severe outbreaks may be.
These tools could help farmers prepare earlier and select management strategies that match current and future pest pressure—an increasingly important need as climate patterns continue to shift.