FHB

Fusarium head blight (FHB), also known as scab, is a fungal disease of cereal crops that reduces yield and grain quality. It primarily affects wheat and barley, and can occur on other small grain cereals such as oats and triticale. The disease is caused by Fusarium species, most notably Fusarium graminearum sensu lato, with other Fusarium species such as F. culmorum, F. poae, and F. avenaceum contributing in various regions.

Symptoms include bleaching or bronzing of spikelets, shriveled and discolored kernels, and, under favorable conditions, visible pink to salmon or white-to-pink spore masses on infected kernels or on the floret tissues. Infected heads may appear discolored and partially blighted. The disease can lead to reduced grain yield, lower test weight, and poor seedling vigor. Many Fusarium species produce mycotoxins, particularly deoxynivalenol (DON, vomitoxin) and zearalenone, which can contaminate grain and pose risks to animal and human health.

The FHB life cycle begins with overwintering on crop residues. Infected residues release spores during moist, warm weather and are dispersed by rain splash and wind to flowering heads, making the susceptibility period during anthesis (flowering) critical. Warm, humid conditions during flowering favor infection and disease development.

Management is integrated and includes crop rotation and residue management to reduce inoculum, using resistant or less-susceptible varieties, and applying fungicides at flowering when risk is high. Fungicide efficacy varies with timing, product, and pathogen population, and resistance management considerations are important. Monitoring and grain testing for DON and other mycotoxins are used to manage grain safety and market requirements.