Septoria leaf spot
Septoria leaf spot, also called méelanose, mainly affects American Vitis and muscadine grapes. Angular, reddish brown to black spots 1 to 2 mm in diameter appear after midseason. Nearing veraison, lesions become larger with diffuse margins. Fruiting bodies may be seen with a hand lens. The area surrounding the spots may be yellow. The fungus overwinters in infected leaf debris.
Septoria leaf spot is a minor foliage disease in the eastern and midwestern United States.
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