Brown stem canker

Signs Plants infected with citrus canker have characteristic lesions on leaves, stems, and fruit with raised, brown water-soaked margins usually with a yellow hallow effect around the lesion. Incubation is typically 14-60 days. Older lesions may fall out, creating a shot-hole effect. Fruit production declines and then stops. The disease ultimately kills the tree. 

Symptoms Dark brown spots on leaves in the late spring. These drop out leaving a "shot hole" appearance. Cankers usually occur on plum tree trunks and cherry branches. Initially, amber-colored gum exudes from a slight depression. Leaves become yellow and stems die back. 

Leaves with brown edges. Cause Bacterial canker. Lower leaves wilt and curl up stems develop light-colored streaks and are brown and mealy inside. See page 229 for an illustration of this disease. Destroy infected plants. To prevent problems, presoak seed in 10 percent bleach solution, and avoid wounding plants. Don t touch plants when they are wet to avoid spreading the disease. 

Symptoms Early blight symptoms appear first on lower leaves as brown spots with concentric rings these spots eventually spread to cover the leaves. Affected leaves drop early, exposing fruit to sunscald. Spots and cankers may also appear on stems. 

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