Felt fungus

Felt fungus, scientifically known as Septobasidium bogoriense, is a unique type of fungal infection that manifests as thick, felt-like growths on the bark of woody plants. This pathogen is known for its complex biological relationship with scale insects, where the fungus lives in a symbiotic state, benefiting from the insects' presence on the host tree.

The disease primarily affects various tropical and subtropical trees, with Indian mango (Mangifera indica) being a notable host. The fungus thrives on the stems and branches, often covering significant portions of the bark in its characteristic grayish-brown, velvety-textured mycelial mat.

Symptoms are easily identifiable: the appearance of irregular, crust-like patches on the bark that feel spongy or felt-like to the touch. These patches do not typically penetrate deep into the woody tissue, but they physically obstruct the surface, leading to localized stress for the plant's bark tissues.

Development and spread are strongly correlated with high humidity levels and the population density of scale insects. Since the fungus relies on these insects for habitat and nutrition, its prevalence is often much higher in orchards where insect management is neglected or where environmental conditions favor stagnant air within the canopy.

The impact of felt fungus includes the weakening of the host tree's overall vigor and potential dieback of affected branches. To effectively manage this disease, growers should focus on

• pruning infected branches,
• implementing an integrated pest management program to control scale insects,
• maintaining good air circulation within the tree crown,
• applying copper-based fungicides when necessary.