Blight of Sunflower

Síntomas

Brown spots may be found on leaves, petioles, stem, sepals, and petals of the host plant. The fungus causes seedling blight and head rot disease. On the leaves, the lesions are dark-brown with a paler margin and a yellow halo. At the disease progresses, the size gets increased to about 2-3 cm diameter and eventually coalesce to produce an irregularly shaped lesion, causing blighting and withering of leaves. These will be surrounded by chlorotic zone with the grey-white necrotic center. Spots first appear on the lower leaves and subsequently spreads to middle and upper leaves. On the stems, lesions occur as circular, elongated or striated black spots. On the sepals and petals, the spots are similar to those on the leaves but are smaller (0.5-2 cm diameter) and coalesce. The consequences of infection are blight and defoliation, destruction of the flowers and seed-heads, wilting, cracking of the stem and ultimately death of the plant. Sometimes rotting of flower heads also occurs.