Corinectria canker

The disease is caused by the ascomycete fungus Corinectria fuckeliana. This pathogen is a significant threat to various conifer species, particularly spruce, causing bark and cambium necrosis that can severely compromise the structural integrity and health of the tree.

The infection manifests primarily as localized cankers on stems and branches. The fungus acts as a wound parasite, entering the host through mechanical injuries, pruning cuts, or openings created by insects, subsequently colonizing the phloem and cambium tissues.

Common symptoms include sunken, necrotic bark lesions, often accompanied by resin flow at the site of infection. As the fungus girdles the stem or branch, the needles distal to the lesion turn yellow or brown, wither, and eventually drop, indicating a disruption of systemic nutrient flow within the affected tree limb.

Favorable conditions for the spread of Corinectria fuckeliana include high humidity, cool temperatures, and poor air circulation. These conditions allow spores to germinate readily on susceptible wound sites. Consequently, dense plantations and forest stands with limited sunlight are particularly vulnerable to outbreaks.

The economic and ecological impact of this disease is significant, as it leads to growth retardation, increased susceptibility to secondary pests, and potential tree mortality. Effective management is essential to prevent the spread of the fungus within commercial forests and ornamental plantations.

Recommended management and prevention strategies include:

• sanitary pruning to remove infected branches;
• application of wound paint or copper-based fungicides to pruning sites;
• maintenance of appropriate tree spacing to improve airflow;
• regular monitoring of tree health to detect early infection signs;
• proper disposal of infected plant material to reduce spore load.