Corynascus

Corynascus is a genus of thermophilic and thermotolerant ascomycete fungi that are commonly found as soil saprotrophs, but under specific conditions, they can act as opportunistic pathogens. This microorganism belongs to the Chaetomiaceae family and is recognized for its ability to decompose complex organic compounds, including cellulose and lignin.

This fungus affects a wide range of agricultural crops, including cereals, legumes, and vegetable crops grown in greenhouses. It poses a particular threat to seeds and seedlings during periods of high temperatures, which often occurs due to improper storage conditions or elevated temperatures within greenhouse environments.

Symptoms of infection manifest as seed decay, stunted seedling growth, and the appearance of dark necrotic spots on the roots or the basal part of the stem. In cases of severe infection, a characteristic moldy growth consisting of fungal fruiting bodies (perithecia) can be observed on the substrate, ultimately leading to the death of young plants.

The development of Corynascus is facilitated by high substrate temperatures (ranging from 35 to 50 degrees Celsius) and excessive moisture. As a thermophile, the fungus thrives in composts, organic-rich soils, and environments where other microorganisms are inhibited by high heat, providing it with a significant competitive advantage.

The economic impact of the disease includes significant thinning of crop stands, reduced seed germination vigor, and the degradation of organic fertilizers. To prevent outbreaks, it is essential to maintain proper temperature control for seed storage, perform thorough sterilization of greenhouse soil, and apply fungicidal seed treatments before planting:

• Ensuring proper aeration of soil and compost mixtures.
• Prompt removal and destruction of infected plants.
• Monitoring and regulating humidity levels in storage facilities.
• Implementing crop rotation to reduce the primary inoculum in the soil.