Extreme Winter Has Mixed Impact On Pest Populations

The long, cold winter may not have had as big of an impact on certain insects as people hoped for.

There are reports that the extreme winter killed off a portion of invasive insects, like the emerald ash borer, but other pests, like mosquitoes and ticks, are more adapted to Wisconsin’s climate and likely survived the brutal temperatures.

La Crosse County’s vector control manager Dave Geske says the number of mosquitoes is more dependent on warmer temperatures and rainfall, not the winter.

“The mosquitoes we have here, the majority overwinter as eggs,” said Geske. “Those eggs can stay viable through really difficult conditions. Some of the species we have here you can find in Alaska — (the) Arctic Circle even.”

Wisconsin is home to 55 mosquito species.

Ticks are a little more unpredictable. University of Wisconsin-Madison’s Department of Entomology professor Susan Paskewitz says the early snowfall likely kept the ground warm enough for deer ticks this winter, but it’s too early to tell. She said it’s possible the lone star tick, which has been slowly arriving in Wisconsin from the south, could not handle the extreme cold.

Paskewitz says some major tick hosts, like white-footed mice and white-tailed deer, did not do well this winter.

“It certainly is possible that with the loss of a major host, a year from now we might see some real differences in Lyme disease,” said Paskewitz.

Paskewitz says this year they’ll be looking to see how the brutal winter affected tick-borne illnesses, like Lyme disease and the West Nile virus from mosquitoes.