Stem smut of sorghum

Stem smut of sorghum, caused by the fungal pathogen Sporisorium culmiperdum, is a significant disease affecting various sorghum species. This pathogen is categorized as a systemic infection that targets the internal tissues of the stem, profoundly impacting the plant's overall development and grain production capabilities.

The disease primarily affects Sorghum bicolor and related grass species. The pathogen is disseminated via teliospores that can persist in the soil for several seasons or remain attached to the seed surface. This durability makes the management of Sporisorium culmiperdum a critical challenge for agronomists.

Symptoms of the infection include the formation of irregular galls and swellings along the stems. As the disease progresses, the plant displays stunted growth, shortened internodes, and often fails to develop a healthy panicle. Upon maturity, these galls rupture, exposing masses of black, powdery teliospores.

The infection process occurs primarily during seed germination when fungal spores penetrate the young coleoptile. Environmental factors such as soil temperature and moisture levels during the early vegetative stage play a decisive role in the severity of the disease outbreak across the field.

Effective management strategies require a combination of chemical and cultural practices. Seed treatment with systemic fungicides is the most essential preventative measure to eliminate pathogens present on the seed coat. Additionally, rotation with non-host crops and selecting resistant cultivars are recommended to reduce the buildup of soil-borne inoculum.