Brown Stripe Downy Mildew of Maize

Dalili

Early-stage symptoms are visible as flecks or blobs on the lowermost leaves, giving them a burnt appearance. These will enlarge lengthwise and coalesce to narrow inter-veinal striping (3-7 mm) and may extend to the full leaf length. These yellow stripes will become yellowish-tan to purple and ultimately turn brown. Lesions start developing on lower leaves as narrow chlorosis or yellow stripes, 3-7mm wide with well-defined margins and are delimited by the veins. Under high moisture conditions, greyish-white downy growth will appear on the lower side of the leaves. The leaf veins are not affected thus laminar shredding is uncommon. Only under severe infection, leaves are torn apart. Premature defoliation and suppression of ear emergence are symptoms of later stages of the disease. In contrast to crazy top disease, no malformation, stunting or leaf thickening that belongs to the downy mildew symptoms occur. Seed development may be suppressed, and the plant may die if blotching occurs prior to flowering.