Tetracladium

Tetracladium (lat. Tetracladium) is a genus of fungi belonging to the group of aquatic hyphomycetes. Although most species of this genus are traditionally considered saprotrophs living in water bodies and decomposing plant debris, some studies indicate their role in plant pathogenesis, especially in conditions of high soil moisture or during colonization of the rhizosphere.

The pathogen belongs to the Deuteromycetes. The type of disease caused by representatives of this genus is most often classified as a specific root rot or damage to young shoots under conditions of excessive moisture. The fungus actively colonizes organic substrates and, under certain conditions, switches to a parasitic mode of life on weakened tissues.

The crops affected mainly include vegetable crops, cereals, and ornamental plants grown in hydroponics or on waterlogged substrates. The pathogen is also frequently found on the roots of cultivated plants in river floodplains, where the microclimate facilitates the spread of aquatic fungi.

Symptoms of infection include darkening and softening of the root system, stunting of the plant's above-ground parts, and the appearance of necrotic spots on the root collar. Under high humidity, a characteristic whitish mycelium consisting of specific conidia of Tetracladium may develop on the surface of the affected tissues.

• Optimal conditions: temperature from +10 to +20°C.
• High soil or substrate moisture.
• Presence of plant debris in the soil.
• Poor aeration of the root zone.

The harmfulness of the fungus lies in reducing the root system's ability to absorb nutrients and water. This leads to stunted development, leaf chlorosis, and eventually plant death, especially during the seedling stage. Prevention includes crop rotation, improving soil drainage, using high-quality sterile substrates, and applying fungicides when the first signs of rot are detected.