Tomentose conk

Taxonomic classification and pathogen type: The tomentose conk (Inonotus tomentosus) is classified within the kingdom Fungi, family Hymenochaetaceae, genus Inonotus. It is a wood-decay fungus that acts as a serious root and butt rot pathogen. Being a basidiomycete, it functions as a parasite that invades the vascular tissues of conifers, causing significant structural damage to the host.

Diseases and host plants: This pathogen primarily attacks coniferous species such as spruce, fir, pine, and larch. It causes a progressive white heart rot that originates in the root system and extends into the lower stem. This leads to substantial decay of the heartwood, weakening the overall mechanical stability of the tree and causing internal damage.

Biology and life cycle: The fungus spreads through the dispersal of basidiospores that infect wounds in roots or the root collar. Additionally, spread occurs via root-to-root contact in stands. Once established, the mycelium penetrates the wood, breaking down lignin and cellulose. Fruiting bodies (conks) emerge near the base of the tree or on roots, exhibiting a distinct, velvety to tomentose surface.

Developmental conditions and economic impact: High soil moisture and poor site drainage favor the development and spread of Inonotus tomentosus. The damage caused by this pathogen includes reduced timber volume, increased vulnerability to windthrow, and mortality of mature trees. It persists in infested stumps and roots, serving as a reservoir for future infections within the forest stand.

Protective measures and control: Management focuses on the removal of infected trees and stumps during harvest to reduce inoculum levels. Avoiding mechanical root damage during silvicultural activities is crucial to prevent site infection. In nursery settings, using sterilized soil and ensuring adequate drainage can minimize the incidence of root rot in young seedlings.