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Atropellis spp.

A. piniphila, Courtesy of EPPO - J.C. Hopkins, Canada

EPPO code

ATRPPP (A. piniphila)
ATRPPC (A. pinicola)

Synonym

Atropellis piniphila and A. pinicola

Common names

English names: Twig blight of pine, branch and trunk canker of pine
Nordic names: Nåletrækræft (DK)

Major host plants

Several Pinus species are hosts, but the main host is P. contorta.

Symptoms

New cankers show no external sign of the underlying infection of dark-brown, necrotic spots, 5 mm in diameter. The first external symptom is a drop of resin on the bark surface. Fresh resin is found during the summer at the margin of cankers. Cankers are elongated and flattened, but deep and covered with bark which is cracked; they occur particularly at the branch whorls on young branches. Multiple stem cankers may be found. The canker development is slow.

A. pinicola, Courtesy of EPPO - J.C. Hopkins, Canada

See more pictures on EPPO´s website:

A. piniphila
A. pinicola

Distribution

Atropellis spp is present in North America. The fungi has not been recorded in the EPPO region.

A map can be downloaded from EPPO's website. See instructions here

Biology

Pine tissue more than 5 years old but less than 30 years old is infected. Infection occurs mainly at the branch nodes, and occurs readily through pruning wounds. For A. pinicola the infection apparently occurs through uninjured bark or leaf scars. The primary source of inoculum is ascospores, released from cankers in wet weather. Conidia are produced in mucilaginous masses on the bark surface. Although relatively more cankers are found on pines in wet habitats, the greatest amount of inoculum is produced by stem cankers in dry sites. The mycelium grows more rapidly in the xylem than the bark, but rarely invades the pith.

Major pathway(s)

Under natural conditions, Atropellis spp. spread by ascospore dispersal within pine stands. There is evidence that ascospores are primarily air-disseminated, although rain may well play a secondary role in dispersal. In international trade, logs with bark may contain ascospores or traces of mycelium, as may cankers on younger branches and twigs of growing material.

Detection and inspection

Timber of Pinus from countries where the disease occurs should have had the bark removed; however, it is possible that removal of bark may be ineffective as a safeguard if it does not eliminate superficial or deep cankers which may contain mycelium or apothecia, and so any material with canker lesions should be carefully inspected. If isolated bark of Pinus is imported from countries where the disease occurs, the consignment must be heat treated. Particular attention should be paid to the younger branches and twigs of growing material of Pinus consignments from countries where the disease occurs.

 

Pest status and importance

A. pinicola is important on P. contorta on which it can cause extensive branch and stem cankers leading to malformation and lowering of wood quality. The disease is rarely important on other pines and generally never sufficiently severe to cause tree death.

Source of information

See further information here:

Author: Jorma Rautapää
Editor: Christiane Scheel

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