Atropellis Canker

Atropellis piniphila (Weir) Lohman & Cash

From: Field Guide to Diseases and Insect Pests of Idaho and Montana Forests, USDA Forest Service Northern Region, Publication Number R1-89-54

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

Distribution. – Locally heavy infections are known to occur in the northernmost counties of Idaho and western Montana. Occasional stands with heavy infections occur throughout the range of the hosts.

Identification. – Heavy resin flow results from stem cankers. The bark is usually tight over dead cambium (fig. 14). Dark blue or black staining in sapwood under a canker is observed by cutting into the wood (fig. 15). 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.

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Figure 14. - Atropellis Canker on a lodgepole pine stem. The bark is tight, and dead branches are often present within the cankered areas.	Figure 15. - Black staining of the sapwood beneath an Atropellis Canker helps distinguish Atropellis from other stem cankers.

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.

Link to Images in Forestry Images

References.

Anonymous. 1982. For. Insect & disease identification and management. USDA For. Serv., Northern Region; Idaho Dept. of Lands, Insect and Disease Control; Montana Dept. of State Lands, Division of Forestry. 192 p.

Bega, R. V. 1978. Diseases of Pacific Coast conifers. USDA For. Serv. Ag. Hndbk. No. 521, 206 p.

Funk, A. 1981. Parasitic microfungi of western trees. Canadian Forestry Service, Pacific Forest   Research Centre BX-X-222, 190 p.

Hepting, G. E. 1971. Diseases of forest and shade trees of the United States. USDA For. Serv. Ag. Hndbk. No. 386, 658 p.

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