Canker Stain
- Caused by Ceratocystis fimbriata f. sp. platani, a fungus, canker stain disease can be fatal. This fungus enters the tree through wounds and causes twig dieback, thinning foliage and reduced leaf size. Elongated cankers on the trunk and large branches are usually sunken and may be hidden underneath the bark. Wood beneath the cankers is darker than surrounding areas. Use care with gardening tools, especially lawnmowers that can nick upper roots. Sterilize gardening tools between uses to avoid spreading infection. No chemical controls are available. To prevent a dead tree from falling on your house or spreading infection to healthy trees, have infected sycamores removed.