Atropellis canker

Atropellis tingens is a fungal pathogen responsible for causing Atropellis canker, a chronic disease primarily affecting pine species. The fungus infects the bark, cambium, and sapwood, leading to the formation of localized lesions that significantly impede the tree's vascular function and structural integrity over time.

The primary hosts for this pathogen are various members of the genus Pinus. The fungus typically gains entry into the host through bark fissures, wounds caused by insects, or mechanical damage. Once established, the mycelium spreads within the living tissue, causing the death of the cambium layer and leading to the typical canker formation around the infection point.

Symptoms of the disease are characterized by resin flow at the site of infection and the development of depressed, often elongated, cankers on the stems or branches. The affected wood frequently exhibits a dark blue or black stain, which is a key diagnostic feature of this condition. Small, dark, disc-like fruiting bodies (apothecia) often appear on the bark within the cankered zones during favorable weather.

The spread of the disease is facilitated by spores that are dispersed by wind and rain splash. Development of the fungus is highly dependent on environmental conditions, particularly moisture levels and forest density. Dense, poorly ventilated stands provide an ideal environment for spore germination and infection, especially in trees already weakened by environmental stress or poor management practices.

Management strategies for controlling Atropellis canker focus on silvicultural practices aimed at reducing the inoculum source:

• Prompt removal and disposal of heavily infected trees during sanitary logging.
• Ensuring proper stand density to promote airflow and reduce ambient humidity.
• Avoiding mechanical injury to healthy trees during thinning or other forest operations.
• Monitoring vulnerable stands closely to detect early stages of infection before the pathogen spreads significantly.