Which symptom is associated with Cytospora canker?

Which symptom is associated with Cytospora canker?

• A. White patches of resin ooze from cankered areas on branches
• B. Leaves with brown lesions and witches' broom
• C. Premature leaf drop with yellowing
• D. Gumming on the trunk only

Answer: (A)

Cytospora canker is diagnosed most reliably by resin, or gum, exuding from cankers on woody tissue. When the fungus invades branch bark, the tree responds by producing a sticky resin that oozes out of the canker, often appearing as white patches of sap on the surface before it dries. This sap-outflow from affected areas is a characteristic and visible sign of the disease, helping distinguish it from other problems. Other signs, like leaves with brown lesions and witches’ broom, premature leaf drop with yellowing, or gumming limited to the trunk, are less specific to Cytospora canker and can occur with a range of stresses or different pathogens. The resin ooze from cankers on branches is the symptom most closely tied to Cytospora’s effect on the tree.

Cytospora canker is diagnosed most reliably by resin, or gum, exuding from cankers on woody tissue. When the fungus invades branch bark, the tree responds by producing a sticky resin that oozes out of the canker, often appearing as white patches of sap on the surface before it dries. This sap-outflow from affected areas is a characteristic and visible sign of the disease, helping distinguish it from other problems.

Other signs, like leaves with brown lesions and witches’ broom, premature leaf drop with yellowing, or gumming limited to the trunk, are less specific to Cytospora canker and can occur with a range of stresses or different pathogens. The resin ooze from cankers on branches is the symptom most closely tied to Cytospora’s effect on the tree.