Sorghum anthracnose

The causative agent of this disease is the fungus Colletotrichum lineola, known as a primary pathogen of sorghum crops. It is a highly aggressive parasite that targets the vegetative and reproductive tissues of the plant. The fungus survives unfavorable conditions by forming sclerotia or surviving as mycelium in crop debris, ensuring its persistence in agricultural soils across seasons.

The disease primarily affects various species of the Sorghum genus, including grain sorghum, forage sorghum, and sudangrass. Under favorable conditions, the host range may extend to other closely related grass species. The pathogen attacks leaves, stalks, and floral structures, causing significant physiological disruption and reducing the overall vitality of the plant.

Symptoms initially appear as small, oval-shaped lesions with a characteristic red or dark brown margin. As the fungal infection advances, these spots expand into necrotic streaks, eventually covering large portions of the leaf surface. A diagnostic feature is the presence of black acervuli within the lesions, which release masses of conidia that can be spread by splashing water or wind.

The development of Colletotrichum lineola is heavily dependent on weather conditions. High humidity and temperatures ranging from +25°C to +30°C are optimal for the germination of spores and the penetration of the fungus into the plant tissue. Frequent rainfall is particularly critical for the secondary spread of the disease throughout the field during the growing season.

Economic damage caused by this pathogen is substantial, often resulting in severe stalk rot, lodging, and reduced grain yield. Effective management requires an integrated approach that includes:

• Planting resistant sorghum hybrids
• Rotating crops to break the pathogen cycle
• Removing or burying crop residues
• Using certified fungicide-treated seeds
• Applying foliar fungicides during high-pressure periods