Champaign, Ill. – A warmer, wetter winter has caused higher than normal soil temperatures across the state, according to Jennie Atkins and Kelly Estes of the Prairie Research Institute. These conditions could be helping agriculture pests survive the season.
Illinois has experienced warmer weather than usual this winter. Overall, temperatures averaged 33 degrees for the season, 4 degrees above the long-term average. Winter 2019-2020 is the 12th warmest on record for the state.
The state has also experienced higher soil temperatures. Temperatures at depths of 4 inches under bare soil have averaged 37 degrees for the winter (December–February), 3 degrees warmer than the long-term average.
All Illinois regions had temperatures below freezing during the season. However, these periods were generally short, with daily highs often rising to above 32 degrees. Seasonal highs reached into the 50s.
Illinois is ending February with warm and wet soils. On Feb. 29, temperatures at 4 inches under bare soil averaged 36 degrees, with highs ranging from the 30s in northern Illinois to 40s and 50s in the south. Soils remain wet due to heavier than usual precipitation this winter, especially in the south. At the end of February, soil moisture levels were at or above field capacity at most locations monitored.
While warmer temperatures favor insect survivability, repeated swings in temperature (alternating between cold and warm) are more detrimental to pests. This year Illinois didn’t experience the dramatic swings in temperature that occurred last winter. The mild winter could be setting the stage for a comeback for some of field crop pests.
However, it is still important to be observant this spring. Weather events in April and May can impact insect populations going into the growing season, especially if the state has another very wet spring or late cold snap.
For more information, contact Jennie Atkins, manager of the Water and Atmospheric Resources Monitoring program at the Illinois State Water Survey, and Kelly Estes, coordinator of the Illinois Cooperative Agriculture Pest Survey at the Illinois Natural History Survey.
The Prairie Research Institute’s Illinois Climate Network collects hourly and daily weather and soil information at 19 stations across the state. Hourly, daily, and monthly data can be found on the network’s website.