Pictured: Sweeping an alfalfa field. Photo by K. Hamilton DATCP
Overwintered alfalfa weevil adults are resuming activity much earlier than in 2025. The 10-day forecast calls for the start of spring egg laying in southern Wisconsin alfalfa fields.
Minimum winter temperatures were not low enough to significantly reduce adult weevil winter survival, and it will be important to plan for sampling first-crop alfalfa in May. Based on Wisconet two-inch soil temperature data, adult weevils protected in alfalfa stubble or beneath leaf debris were probably not exposed to lethal cold temperatures below the 13°F threshold for this insect, even during the most intense cold period January 22-25…