Two commercial cornfields in south central Iowa were diagnosed with Stewart's disease the week of May 22. Although commercial field corn does show variable tolerance to the disease and widespread economic loss is not likely, these fields are proof that the disease can infect some hybrids. Even among exposed plants within a given hybrid, some may be infected and others may not. In one field south of Albia, 2 percent of plants had been killed, 12 percent showed classic leaf symptoms, and 86 percent were symptomless. The fields with infected plants will be monitored as the season progresses