Fusarium head blight

Pathogen and disease type. The disease is caused by the fungus Fusarium graminearum, a prominent species in the complex of fungi causing Fusarium head blight (FHB). This pathogen is highly destructive and can affect the plant at multiple stages, causing crown rot, seedling blight, and significant ear infection. It persists in soil and crop debris for several seasons.

Host crops. Fusarium graminearum primarily targets cereal crops, including wheat, barley, oats, and rye. It is also a major pathogen of maize, where it causes ear rot. This broad host range makes the fungus particularly challenging to manage in intensive agricultural systems where cereals and maize are rotated frequently.

Symptoms and signs. The hallmark of the disease is the premature bleaching of the infected spikelet or the entire head during the grain-filling stage. In humid conditions, a visible pink or reddish fungal growth appears at the base of the spikelets. The resulting grains are often shriveled, chalky, or discolored, which severely compromises the overall grain quality and weight.

Conditions for development. Infection is highly dependent on environmental conditions, particularly warm temperatures and high humidity during the flowering stage (anthesis). Periods of frequent rainfall promote the dispersal of spores from crop residue to the grain heads. The fungal spores settle on the open flowers, which serve as the primary entry point for the mycelial infection.

Harmfulness and protection methods. The impact of FHB is dual: it causes significant yield loss and contamination of grain with mycotoxins such as deoxynivalenol (DON), which are hazardous to human and animal health. Effective management requires an integrated approach:

• Crop rotation to break the pathogen's life cycle.
• Selection of resistant or tolerant cultivars.
• Proper residue management to reduce inoculum levels.
• Application of specialized fungicides at the early flowering stage.