Atropellis piniphila (Weir) Lohman & Cash

Hosts - Lodgepole pine, rarely ponderosa pine. Atropellis pinicola causes a similar disease on western white pine.

Damage - Branch and stem cankers are produced. Single infections in small stems or multiple infections in large stems often girdle and kill trees.

Identification - Heavy resin flow results from stem cankers. The bark is usually tight over dead cambium. Dark blue or black staining in sapwood under a canker is observed by cutting into the wood. Minute black fruiting bodies are cup-shaped on short stems emerging from bark at canker margins. Cankers are usually many times longer than wide. The cankers may cause vertical seams which give stems a fluted appearance.

Similar damages - Sunscald often causes cambium death with bark remaining tight on stem. Comandra and stalactiform blister rusts produce stem cankers which are somewhat similar to Atropellis cankers but they do not cause blue-black staining.

Management - Old bole cankers can girdle and kill trees. Mortality is most common in small, suppressed trees. Maintain a vigorous growing stand with adequate spacing densities suited for the site.