Crazy top of corn, caused by the fungus Scleroph thora macrospora (Sclerospora macrospora), has occurred widely but sporadically in Illinois. The disease is seldom prevalent enough to cause much damage, although losses of at least 60 percent in grain yields have been reported in parts of some fields. Crazy top, when it does occur, is invariably found in localized areas of fields and gardens where the soil becomes waterlogged or flooded between the time the corn kernels germinate and the seedlings are 6 to 10 inches tall.