Their Growth Stages
Adults overwinter on plant debris in your yard, or in nearby woods or fields. They emerge in mid-spring to early summer to lay clusters of 40 to 60 yellow eggs on leaf undersides of the target plants; usually beans. These adults will munch on the new bean seedlings in the meantime. Beetle larvae begin to emerge when temperatures settle between 58°F and 69°F. They munch away until they become beetles and continue to feast on your beans if there are any left.