Producers often ask, “If we have a bad winter, will it reduce our insect pest problems?” Insects have the ability to survive cold weather by a couple of mechanisms. First, they can seek shelter from the cold and secondly, they can produce compounds in their body like antifreeze. These compounds keep the insect from freezing solid which would kill the insect. These are insects who hibernate as adults.

Insects seek shelter under crop residues, under residues in field borders, in the soil and other numerous sites where they can over winter. These shelters provide for moderate temperature changes.

Many insects overwinter by entering a state of hibernation. During this time, their metabolism slow and they use the energy reserves in their bodies until temperatures rise and hey become active. European corn borer over-winter as full-grown larva in corn stalks and weed stems.

Migration is one strategy to avoid killing temperatures. Black cutworm migrates in the spring northward from southern states. Also, fall armyworm and corn earworm are migratory.

The population of the insect and the conditions during its survival in spring has a larger impact than winter conditions. Populations can explode and crash depending on its environment.

Likewise, weather conditions impact the migration of insect pests from the south. Many years, insect pests that migrate may not be economically present to injure crops. This makes for a difficult challenge in predicting insect outbreaks. 

Given these challenges, the best way to manage pests is to plan to scout and carefully watch fields this coming season. Know the conditions and environments that insect pests thrive and know the biology of the insect pest.

For more information, contact Wayne Flanary, Field Specialist in Agronomy, at 816-279-1691, University of Missouri Extension.