Monilochaetes infuscans

Monilochaetes infuscans is a fungal plant pathogen within the kingdom Fungi, belonging to the genus Monilochaetes. It is primarily known for causing a disease called "scurf" in sweet potatoes (*Ipomoea batatas*). This soil-borne fungus poses a significant threat to the quality and storage stability of sweet potato harvests worldwide.

The disease manifests as dark brown or blackish spots on the skin of the sweet potato roots. These lesions may start as small, circular patches but can eventually expand and merge, covering large areas of the root surface. While the internal flesh of the potato usually remains sound, the unsightly appearance and shriveling caused by the loss of moisture significantly reduce the market value of the crop.

The biology of Monilochaetes infuscans involves the production of conidia, which facilitate the spread of the pathogen. These spores can persist in the soil for extended periods, surviving on crop residues or weed hosts. The fungus is moved across fields via irrigation water, contaminated soil movement, or infected vine cuttings used for propagation, making the selection of clean starting material critical.

Development and spread of the fungus are highly dependent on moisture and temperature. It thrives in soils with moderate to high moisture levels and moderate temperatures. Infection often occurs during the active growing season, with the pathogen penetrating the skin of the roots through natural openings or small abrasions caused by soil insects or mechanical equipment.

Management of the disease requires an integrated approach. Farmers should prioritize the use of disease-free slips for planting and implement long-term crop rotation cycles to reduce soil pathogen load. Proper harvest techniques are essential to minimize skin wounds, and curing the sweet potatoes immediately after harvest helps heal minor wounds, significantly reducing the chances of secondary infection during storage.