Anthony Hanson, Extension Post-doctoral associate and Robert Koch, Extension entomologist On January 31, 2019, most of Minnesota had morning lows near or below -30°F (Figure 1). Cold winters help prevent many potential pest insects from establishing here or requires species that cannot survive our winters like potato leaf hopper or black cutworm to migrate up from southern states. Extreme cold can also knock back species that are established here. Figure 1. Morning lows on Jan. 31, 2019; U.S. National Phenology Network: www.usanpn.org. Insect cold tolerance For the most part, insects match the temperature of their surrounding environment, making them "cold-blooded." Wind chill doesn't really affect them, but air temperature does. Even so, many insects can survive temperatures well-below freezing due to their own antifreeze compounds like glycerol. Similar to weather forecasting, insect forecasting can give us a general idea of future insect populations. T...
