LEXINGTON, Ky. — The recent snow and cold should have little effect on developing alfalfa weevil populations. Temperatures must drop below minus 7 to minus 10 F to be lethal to eggs deposited in plant stems. Small larvae are killed by temperatures of around 0 to minus 5 F. Larger larvae are more vulnerable, succumbing at 10o to 15o F.
Alfalfa stems and leaf tips provide some protection, so temperatures in the plant canopy are probably a little warmer than the air temperature. In addition, snow cover provides some insulation.
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— Lee Townsend, University of Kentucky Extension Entomologist
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