Ganoderma Butt Rot Of Urban Trees Description:
Varnish conk, Ganoderma sessile, is a moderately aggressive species of wood decay fungi that attacks hardwoods and deciduous trees. Mushroom growths, called conks, form on the lower portion of the trunk at the base of the tree. Their conks start as creamy blobs that become hard as they age with a glossy, reddish upper surface.
Hosts:
Many deciduous trees are susceptible to this fungal species.
Biology & Symptoms:
Spores released by the conks disperse in the wind and infect other trees through wounds on the trunk or woody roots. It then causes a white rot of the host trees wood, which leads to strength loss.
Management:
Infected tree trunks should be regularly tested for soundness. There are currently no effective fungicides for this disease, so prevention is crucial. Try to minimize or eliminate any wounds to the trunk.