Seedling blight, due to planting scabby kernels, is an important disease effectively controlled by seed treatment fungicides. The Fusarium fungi also cause root rot and crown rot diseases in small grains. Corn is an important host for these fungi in the Corn Belt. On corn these fungi cause ear, stalk and root rot diseases. The severity of scab infection varies greatly from year to year.
Severe infection occurs during the flowering stage and shortly afterward when wet weather prevails.
Two to three days of light rain during this period will initiate epidemics. If the weather is dry during this critical period, the grain crop will be essentially scab-free. In Ohio, during years of favorable weather, the incidence of infected heads has been as high as 100 percent in some fields. In these cases over 50 percent of the spikelets have been destroyed. Other affects of scab include floret sterility, poor test weights due to shriveled grain and yield loss.