By Scout Nelson
Nebraska’s frigid winter raised hopes that insect pest populations might drop due to cold-related mortality. However, most soil temperatures remained above critical thresholds, meaning key pests likely survived.
Soil temperatures across five key Nebraska locations remained largely above 30°F. Even during two major cold snaps in January and February, most sites only briefly dipped below 20°F. A snow cover during the February cold period helped stabilize soil warmth.
Western Corn Rootworm (WCR):
WCR eggs overwinter in the soil and are vulnerable to prolonged exposure below 14–19°F. In most areas, 4-inch soil temperatures remained above this range. However, in Scottsbluff, January temperatures briefly fell to 10°F. Combined with dry soil, this may have caused some WCR mortality.
Western Bean Cutworm (WBC):
WBC prepupae overwinter at depths of 5–10 inches. These insects are not freeze-tolerant and die at 9.3°F. While most regions were warmer, Scottsbluff’s brief drop may have impacted local populations.
Wheat Stem Sawfly:
This pest overwinters in protected wheat stubble. Soil insulation from residue and snow keeps sawfly larvae well above lethal temperatures, meaning winter survival was likely high statewide.
Other Insects:
Some insects overwinter on the surface or in exposed areas. These may have experienced higher mortality where snow cover was thin or absent.
Photo Credit:istock-bee-photobee
Categories: Nebraska, Crops, Corn, Wheat, Weather