The bean leaf beetle has undergone tremendous population changes in Iowa during the last 16 years. From 1989 to 1996, the populations (both first generation and second generation) were very insignificant. But beginning in 1997, the population in central Iowa began to accelerate nearly yearly until it reached a historical high in 2002. Populations that year were nearly 400 times larger than what we had experienced during the mid-1990s. Since that time the population has returned to more normal levels and is similar to what we witnessed at the beginning of the beetle explosion in the late 1990s.