Tomentella radiosa

Tomentella radiosa is a basidiomycetous fungus known for its role as a potential soil-borne pathogen. While often found as a decomposer in forest environments, it can act as a pathogen under specific agricultural conditions, particularly affecting the root systems and root collars of susceptible plants by inducing decay and inhibiting nutrient uptake.

The disease is classified as a root and collar rot. The pathogen invades the cortical tissues, leading to necrosis and cellular structural breakdown. This biological damage disrupts the transport of water and essential nutrients from the roots to the foliage, which is the primary cause of the observed physiological decline in the infected host.

The key symptoms include dark lesions on the roots and the appearance of a thin, radiating mycelial mat, which gives the fungus its specific name. Over time, these symptoms manifest as leaf wilting, canopy yellowing, and eventual plant collapse. Severe infections often occur in clusters, creating patches of dead or stunted plants within a field or nursery setting.

The development of the fungus is highly sensitive to soil moisture and oxygen availability. It thrives in waterlogged or compacted soils where drainage is poor. The spread is primarily through spores in water films or via contaminated soil particles, which can remain in the field for extended periods if host debris is not properly managed.

Effective management requires a multi-faceted approach focusing on soil health and sanitation to prevent outbreaks. Recommended practices include:

• Improving soil drainage and aeration to reduce pathogen activity.
• Strict field sanitation by removing crop residues after harvest.
• Practicing crop rotation to break the pathogen's life cycle.
• Monitoring irrigation practices to prevent prolonged surface wetness.
• Using appropriate fungicide treatments when environmental conditions favor disease outbreaks.