Champaign, Ill. - Warmer winter soils may have an impact on agriculture and crop pest control this spring, according to researchers at the University of Illinois' Prairie Research Institute.
Statewide temperatures at depths of 4 inches under bare soil have averaged 36.3 degrees so far this winter, according to Jennie Atkins, Water and Atmospheric Resources Monitoring (WARM) program manager at the Illinois State Water Survey, a division of PRI. The temperature is 2.5 degrees above the long-term average, but 0.4 degrees lower than last winter. While there were periods in December and early January in which averages fell below freezing, soils have been warmer than normal for most of the season.
Soil temperatures have been higher than normal throughout the state. The highest temperatures have been reported in southern Illinois with a seasonal average of 39.4 degrees, 2.6 degrees higher than normal. Northern Illinois had the lowest temperatures with an average of 33.1 degrees or 1.1 degrees above the long-term average.
Soils have been steadily warming since early February. On February 21, soil temperatures averaged 52.9 degrees or 20.3 degrees warmer than the long-term average. Daily highs reached into the low 60s at several stations in central Illinois.
Under sod, soil temperatures were higher than normal, averaging 38.4 degrees at 4 inches and 38.5 degrees at 8 inches this winter, 3.1 and 2.5 degrees higher than normal, respectively.
With these mild temperatures, one question everyone has been asking is, “What does this mean for pest pressure this spring?” Kelly Estes, state agricultural pest survey coordinator with the Illinois Natural History Survey, a division of PRI, has been discussing this topic at the recent University of Illinois Crop Management Conferences.
“Generally, milder winters do allow for greater survivorship of overwintering pests,” Estes said. There are a few things to take into account, though. While some pests overwinter here, others will migrate.”
Of the ones that do overwinter here, the previous year's population will be a factor (if the population was low in 2016, it's going to start low in 2017).
“It's also important to remember that favorable conditions for pests are also favorable for natural enemies,” she said. “There is still quite a bit of time before we'll know for sure, but the possibilities are there for an active spring.”
The Illinois State Water Survey's WARM Program collects hourly and daily weather and soil information at 19 stations across the state. Daily and monthly summaries can be found at the WARM website (http://www.isws.illinois.edu/warm/) and in the Illinois Water and Climate Summary (http://www.isws.illinois.edu/warm/climate.asp).
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Jennie Atkins, Ph.D. - (217) 333-4966, jatkins@illinois.edu
Kelly Estes - (217) 333-1005, kcook8@illinois.edu