Mesosetum smut

The disease is caused by the fungus Sporisorium mesoseti, a basidiomycete pathogen. This fungus is specifically adapted to infect grasses, primarily targeting the inflorescences of its host plants to complete its biological life cycle within the developing flowers.

The host range is mainly concentrated on grass species within the genus Mesosetum. These grasses are typically found in pasture lands and native grasslands where the environment supports the persistence and transmission of this fungal pathogen throughout the growing season.

Symptoms become apparent during the reproductive stage of the host plant. Instead of producing fertile seeds, the plant develops smut sori filled with dark, powdery teliospores. These sori are often enclosed by a membrane that eventually ruptures, exposing the spores to wind dispersal.

The spread of the disease is highly dependent on environmental conditions, particularly moisture and temperature at the time of flowering. High humidity combined with warm weather facilitates the germination of spores on the plant surface, allowing the fungus to penetrate the host tissues effectively.

The economic impact of Sporisorium mesoseti is significant in forage production and seed development. By replacing reproductive parts with spore masses, the pathogen causes total loss of grain yield and can compromise the overall nutritive value and palatability of the forage crops.

Integrated management is essential for controlling this smut. Effective strategies include:

• Utilizing disease-resistant varieties when available.
• Implementing deep tillage to bury infected residues.
• Employing crop rotation to disrupt the life cycle of the fungus in the soil.
• Treating seeds with appropriate fungicides to prevent initial soil-borne infections.