Bean leaf beetle adults are susceptible to cold weather and will die when the temperature falls below -10°C. However, they have adapted to winter by protecting themselves in leaf litter. An overwintering survival model was developed by Lam and Pedigo from Iowa State University in 2000, and is helpful for predicting winter mortality based on accumulating subfreezing temperatures. Predicted mortality rates ranged from 40-90 percent for the 2012-2013 winter (Fig. 1). The northern third of Iowa did experience a colder winter, and more than 80 percent of beetles were not predicted to survive.
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