Atropellis canker of pine

Atropellis canker of pine is a significant forest disease caused by the ascomycete fungus Atropellis pinicola. This pathogen is known for inducing cankerous lesions and tissue necrosis on the stems and branches of various pine species. It poses a substantial threat to forest health by causing wood defects and reducing the overall growth rate of infested trees.

The primary hosts of this disease are trees within the Pinus genus. Different pine species exhibit varying degrees of susceptibility, with many commercially important softwoods being vulnerable. The disease can occur in both natural forests and plantations, often becoming a chronic issue that persists over many years.

Symptoms are characterized by flattened or depressed areas on the bark, which eventually develop into distinct cankers. A key diagnostic feature is the profuse resinosis (pitch flow) that covers the infected area. Beneath the affected bark, the sapwood is often stained with a dark, blue-black or chocolate-brown discoloration, which significantly lowers the commercial timber value.

Environmental conditions that favor the spread of Atropellis pinicola include high humidity and cool to moderate temperatures. The fungus produces small, dark apothecia on the surface of the cankers, which release spores that are dispersed by wind and rain splashes. These spores enter the host through bark cracks, insect wounds, or other minor physical injuries.

Managing the disease requires an integrated approach. The most effective strategy involves systematic forest thinning to improve tree vigor and the prompt removal of infected timber to reduce the inoculum load. Maintaining healthy stands and minimizing physical damage to bark are crucial components of long-term prevention. In high-value areas, regular monitoring and sanitation are necessary to prevent widespread outbreaks.