As warm, moist weather develops, spores are spread by rain or wind to infect flower parts, glumes or other portions of the head. Infections are most frequent and severe at anthesis. Symptoms of Damage Head blight is recognized by premature bleaching of one or all of the spikelets in the head. The infected spikelets are often sterile. The seed in the spikelet stalk, above the point of infection, may not develop.
Diseased heads have small dark spots and exhibit fungal growth with an orange to pinkish tinge.
Infected grain is shrivelled and lighter in weight. Individual kernels are usually whitish in colour. Blight symptoms develop within 3 days after infection if environmental conditions are favourable. Infected heads ripen prematurely. If the point of attachment of the seed head is infected, everything above that point will be white.