Diplodia Leaf Streak
(Stenocarpella macrospora)
Symptoms: Lesions are large (up to 10 cm long), gray-green and elliptical with a water-soaked appearance. Older lesions produce black spots called pycnidia (spore-producing fungal structures).
Risk Factors: Overwinters on corn residue, so continuous corn and no-till management increases the risk of disease. Favored by moderately humid conditions (mean relative humidity = 50% day, 95% night).
Management: Avoid planting into residues from previously diseased plants.
