Chaetomium elatum

The fungus actively grows on seeds, kernels, and straw, forming characteristic dark fruiting bodies called perithecia. During its life cycle, it secretes specific metabolites that can negatively affect the physiological processes of germinating seeds.

This microorganism possesses high cellulolytic activity, allowing it to efficiently degrade organic substrates rich in fiber. This makes it a common inhabitant of crop residues left after harvesting.

In phytopathological terms, Chaetomium elatum is considered one of the components of the fungal complex causing the "black point" disease in cereal crops. Its presence often correlates with other pathogenic micromycetes.

A biological feature of the species is its ability to form large, dark, hair-covered perithecia, which allow the fungus to overwinter in harsh environmental conditions.

On affected seeds and kernels, a dark, olive-black, or grayish moldy coating appears, which represents clusters of fungal perithecia. Affected areas often appear "dusty" or darkened.

In cereal seedlings, severe seed infestation results in stunted growth, darkening of the roots and hypocotyls. The development of the root system is suppressed, leading to sparse emergence.

In the field, symptoms manifest as dark spots on spikes and stems, especially under high humidity during the ripening period. The fungus often colonizes tissues weakened by other pathogens or unfavorable weather factors.

An important diagnostic feature is the presence of rounded or pear-shaped dark fruiting bodies on the surface of the substrate, visible under slight magnification. They may group into clusters, forming a visible coating.

Infected grain loses germination capacity and vigor, and when such material is used for sowing, massive seedling blight or failure is observed at early development stages.

The development of Chaetomium elatum is directly dependent on moisture levels. Excessive humidity during grain ripening or during seed storage is a critical factor favoring disease outbreaks.

The temperature optimum for fungal growth is between 20–25 degrees Celsius, but it can also develop successfully at lower temperatures, allowing it to remain active in the soil during autumn and spring.

Violations of grain storage protocols, where moisture content exceeds 15-16 percent, create ideal conditions for the colonization of kernels by this pathogen, leading to active mold growth.

Inadequate aeration in storage facilities or during seed storage promotes the rapid spread of infection from infected kernels to healthy ones, leading to the spoilage of entire grain batches.

Poorly managed harvests, where grain remains in the field under high humidity and cool weather, significantly increase the risk of spike infection by Chaetomium, creating conditions for epiphytotic development.

The primary damage lies in the reduction of seed quality. Infected seeds have critically low germination vigor, leading to decreased plant density and subsequent yield losses.

The fungus produces toxic metabolites that poison seedlings and lower their immunity, making them more vulnerable to soil-borne pathogens causing root rots.

During grain storage, Chaetomium elatum is an active degrader of starch and protein substances, leading to lower commercial grain quality, color changes, and the appearance of an unpleasant moldy odor.

In agro-ecosystems, the widespread occurrence of the fungus on crop residues creates a high inoculum load, making it difficult to grow cereal crops in monocultures without proper soil treatment.

Economic losses include costs for seed treatment, potential storage losses, and the need for unscheduled agrotechnical interventions for field sanitation.

The primary method of control is the use of high-quality, treated seed material. The application of fungicidal seed treatments effectively suppresses surface infection and protects seeds during early development stages.

Adhering to agrotechnical harvest timing helps avoid exposing grain to prolonged rainfall, which minimizes the risk of spike infection by Chaetomium in the field.

Quality post-harvest drying of grain to the target moisture content plays a crucial role. Storage must be conducted in dry, ventilated facilities with constant monitoring of temperature and humidity regimes.

Crop rotation is a fundamental preventive measure. Alternating cereals with legumes or other crops that are not hosts to this pathogen reduces the accumulation of infection in the soil.

Thorough incorporation of crop residues into the soil or their shredding promotes faster mineralization of organic matter, which deprives the fungus of a substrate for reproduction and limits its survival.