Myrothecium roridum

Fungal Disease

Myrothecium roridum

Fungal Disease

Myrothecium roridum

Fungal Disease

Leaf spot caused by the fungus Myrothecium roridum is a minor disease that can affect cucurbits, including watermelon and muskmelon, though it is rarely seen in Florida. The disease thrives in wet conditions, which favor its development.

Symptoms:

1. Early Stages: On muskmelon, early symptoms include yellow vein-limited discoloration and the appearance of small to large, circular or irregular lesions on the leaves.
2. Lesion Expansion: As the disease progresses, the lesions may enlarge, and the centers of the lesions can break out, giving the leaf a shot-hole appearance.
3. Blighted Sections: In severe cases, lesions can merge to form large, blighted sections on the leaves, reducing the plant's ability to photosynthesize effectively.

Though Myrothecium roridum leaf spot is a minor issue, monitoring for early symptoms and maintaining good field hygiene can help prevent its spread under favorable conditions.