Myxotrichum chartarum

Myxotrichum chartarum is a species of ascomycete fungus often found on cellulose-containing substrates. While primarily recognized as a saprophyte, it can act as a plant pathogen under specific stress conditions, impacting the overall health and economic value of agricultural yields, especially when stored in improper conditions.

The pathogen is known for its ability to decompose organic matter using specialized enzymes. As a type of mold, it belongs to the Chaetothyriales order. Its presence in agricultural fields is often a indicator of high moisture levels and poor decomposition management, where it can transition from decomposing dead matter to infecting weakened living tissue.

The crops affected include various cereals, industrial crops, and stored vegetables. The fungus colonizes seeds, leaves, and stems, often exploiting existing micro-wounds caused by insects or other pathogens. In stored products, it can cause rapid deterioration if ventilation is insufficient and humidity levels exceed the critical threshold.

Symptoms of the infection typically include the appearance of a dusty, velvet-like coating on the surface of the plant material.

• The mold usually presents in shades ranging from light gray to dark brown.
• Infected plant tissues lose their structural integrity and may develop dark, necrotic spots.
• Seed germination rates significantly decline when the fungus covers the seed coat.

The development and spread of Myxotrichum chartarum are driven by environmental factors, most notably high relative humidity (above 80%) and moderate temperatures. It spreads through microscopic spores that are easily dispersed by wind, water splashes, and agricultural machinery, making hygiene in the field and storage essential.

Prevention strategies center on maintaining low humidity, proper storage practices, and the use of resistant crop varieties where applicable. Seed treatments with appropriate fungicides are highly effective in preventing initial infection. Maintaining clean field margins and incorporating crop residues correctly into the soil also helps reduce the inoculum levels for the following season.