Cause Nectria cinnabarina, a fungus. It is a common saprophyte on many plant species. The fungus colonizes bark, cambium, and sapwood of stems weakened by freezing, drought, mechanical injury, or other diseases.
Symptoms Twigs and branches die back from cankers. Bark of the canker area may be discolored and contain small coral-pink to black fungus fruiting bodies (perithecia). The disease may follow winter injury, drought, or insect injury. Leaves on affected branches often are dwarfed or wilt later in the season.
Cultural control
- Prune out and burn dead twigs and branches. Make cuts several inches below any sign of infection. Paint large wounds with a tree dressing.
- When pruning, do not leave stubs or make flush cuts up against the branch or trunk.
- Avoid bark injury from mowing or other practices.
- Fertilize and water to maintain tree vigor.
Reference Sinclair, W.A. and Lyon, H.H. 2005. Diseases of Trees and Shrubs. Ithaca, NY. 2nd edition. Cornell University Press.