The study of the dry rot disease of corn caused by Diplodia zeae shows it to be a prevalent disease in Iowa, resulting in losses, the past two seasons, ranging from 3 to 15 percent of the ears at harvest and a 11 percent damage to the seed corn. The loss in stand from diseased seed in many fields a mounted to 15 percent. A still further loss results from nodal infection and weak plants grown from slightly infected seed.