Tar Spot

Triệu chứng

First symptoms are characterized by small, raised yellow-brown spots with a black center on both leaf sides. The spots can be surrounded by circular, brownish lesions with dark edges, commonly called “fish-eye”. The circular, oval, sometime angular or irregular spots can coalesce and form stripes up to 10 mm long. The whole leaf can be covered with spots and surrounding leaf material dries up. Symptoms appear first on lower leaves, spreading to upper leaves. Under severe infestation the spots also appear on husks and leaf sheaths. Leaves may die off completely after 21 to 30 days. This will result in the reduction of marketability.