Sorghum smut

Pathogen and Disease Type. The pathogen Anthracocystis ehrenbergii (formerly Sphacelotheca ehrenbergii) is the causative agent of this systemic fungal disease. It is a type of smut that specifically targets the reproductive tissues of sorghum, disrupting the development of the panicle and replacing healthy floral structures with fungal spore masses.

Host Crops and Infection. This pathogen primarily infects sorghum species, including grain, forage, and sweet sorghum. While it is highly specialized, its impact on sorghum yield can be devastating. Infection occurs systemically, meaning the fungus colonizes the growing point of the seedling and develops internally as the plant matures throughout the season.

Symptoms and Signs. The most characteristic symptom appears during the flowering stage. Instead of a healthy, grain-bearing panicle, the plant produces elongated or swollen galls covered by a membrane. As the fungus matures, this membrane ruptures, releasing a black, powdery cloud of teliospores that spread easily by wind, rain, or mechanical harvesting equipment.

Conditions for Development. The development of Anthracocystis ehrenbergii is highly dependent on environmental factors during the early stages of plant growth. Cool to moderate soil temperatures combined with adequate soil moisture are optimal for teliospore germination and infection. Pathogen survival in the soil is robust, allowing the disease to persist in fields for multiple growing seasons.

Harmfulness and Protection Measures. The economic loss is direct, as the fungus prevents grain formation, rendering infected plants useless for harvest. Effective management strategies include:

• Applying systemic fungicides to seeds before planting.
• Utilizing resistant or tolerant sorghum cultivars.
• Practicing long-term crop rotation to reduce soil inoculum.
• Maintaining field hygiene to prevent the spread of contaminated plant residues.