Bean leaf beetle adults are susceptible to cold weather and most will die when the air temperature falls below 14°F. However, they have adapted to winter by protecting themselves under plant debris and loose soil. Each spring, adult beetles emerge from overwintering habitat and migrate to available host plants, such as alfalfa, tick trefoil and various clovers. As the season progresses, bean leaf beetles move to more preferred hosts, like soybean. Note that while initial adult activity can begin well before soybean emergence, peak abundance can coincide with soybean emergence.
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