Atropellis canker

Atropellis canker is a serious fungal disease caused by species of the genus Atropellis, which induces bark necrosis and deep resinous cankers on the trunks and branches of various coniferous trees. The pathogen primarily targets the cambium layer, causing restricted nutrient flow and the eventual formation of long, sunken lesions on the bark.

The disease is most commonly observed on various species of pine, including lodgepole pine and Scots pine. As a chronic disease, it can persist in a forest stand for many years. It is particularly concerning for commercial timber forests, as the infection can significantly reduce the structural integrity and economic value of the wood due to deep resin impregnation.

Key symptoms include the presence of depressed areas on the bark, profuse resinosis (bleeding), and cracking of the bark surface. When the outer layer is removed, the inner wood appears dark brown or blackened and highly resin-soaked. Tiny, black, disc-shaped fruiting bodies known as apothecia appear on the surface of the infected bark, serving as the source of further infection.

Environmental conditions that favor the disease include high humidity, low air circulation, and dense stand conditions. The spores are typically spread by wind and rain splashes. Once the spores land on the bark, they penetrate through natural openings or mechanical wounds, initiating the slow but progressive infection process that weakens the tree over time.

Economic damage is substantial as the wood becomes brittle and structurally compromised. Preventing the spread of Atropellis canker requires rigorous silvicultural practices, including the systematic removal of infected individuals to reduce the inoculum level in the area.

• Sanitary thinning of infected stands.
• Avoiding damage to the bark during thinning operations.
• Monitoring forest health for early signs of resinosis and bark depression.