Paspalum smut

Paspalum smut is a fungal disease caused by the pathogen Sporisorium paspali-notati. This basidiomycete fungus targets grasses within the Paspalum genus, specifically impacting the reproductive structures and causing significant losses in seed production and plant vigor.

The primary host for this fungus is Paspalum notatum, a vital forage grass utilized globally in tropical and subtropical regions. The infection cycle typically begins when teliospores germinate and infect the developing meristematic tissues of the host plant, eventually localizing within the emerging inflorescences.

Visible symptoms manifest as the transformation of floral parts into black, spore-filled sori. Instead of producing viable seeds, the infected panicles become distorted and filled with a dusty mass of teliospores. These darkened structures are the most distinctive sign of the disease, often becoming brittle as the spores are released into the environment.

The spread of Sporisorium paspali-notati is highly dependent on environmental conditions, particularly high humidity and moderate temperatures, which favor the dispersal of spores by wind or water splashes. Once introduced into a field, the pathogen can persist in the soil or on crop debris, making it difficult to eradicate once it is established.

Management strategies require a combination of preventative practices to reduce inoculum load. These include selecting disease-free seed sources, practicing regular mowing to prevent the dispersal of spores from infected inflorescences, and employing crop rotation where possible. In commercial seed production, targeted fungicide applications during the boot stage may be necessary to protect the emerging panicles.