December, January and February temperatures were all colder than average across Iowa. As a result, the risk for Stewart’s disease of corn in 2009 is low to negligible throughout all of Iowa, based on two predictive models. Stewart’s disease, also known as Stewart’s wilt, is caused by the bacterium Pantoea stewartii. An insect vector, the corn flea beetle, plays a critical role in the plant-to-plant spread of this causal microorganism.