Sedge smut

The disease known as sedge smut is caused by the basidiomycete fungus Anthracoidea caricis. This pathogen is highly specific to the genus Carex (sedges). As a biotroph, it depends entirely on the living tissues of its host plant to complete its life cycle, typically invading the reproductive organs of the sedge species.

The pathogen infects various sedge species found in wetlands, pastures, and meadows. It systematically replaces the ovary tissue within the spikelets with a dark, powdery mass of teliospores. This process effectively sterilizes the infected florets, preventing seed production and potentially reducing the nutritional value and biomass quality of the forage in infested areas.

Symptoms are most visible during the reproductive stage of the plant. Infected spikelets become swollen and eventually burst to release black, soot-like spores. This diagnostic feature distinguishes it from healthy floral structures, making it easily identifiable in the field. The deformation of the inflorescence is the most characteristic sign of the infection.

Disease development is favored by high humidity and cool to moderate temperatures during the flowering period of the host plants. The spores are primarily wind-dispersed, facilitating infection of neighboring plants. Once established, the fungus can overwinter in soil or on plant debris, ensuring that the infection persists in the same habitat over successive seasons.

Control strategies for sedge smut mainly rely on sanitation and cultural practices. Mowing affected areas before the spores are fully mature and released can significantly decrease the inoculum density for the following year. While chemical fungicides are rarely applied in natural meadows, proper grazing management and early harvesting remain the most effective preventive measures to minimize the spread of this smut disease.