If the initial inoculum source is airborne ascospores, the first symptoms generally seen are small necrotic specks on newer leaves or stems. Under cool, moist conditions, the necrotic specks enlarge and coalesce to form large necrotic lesions (6-12 mm in diameter) on young leaves and buds. Lesions forming on pods and leaves are primarily circular to oval (up to 0.5 cm), containing concentric rings of pycnidia, the fruiting bodies of the anamorph which are visible with a 10× hand lens. Lesions that form on petioles and stems are usually elongate, but also will contain pycnidia arranged in circular patterns. Stem lesions vary greatly in size, becoming 3 to 4 cm in length, and often girdling stems resulting in breakage.
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