Leaf blight

Leaf blight (Helminthosporium turcicum) Attacks sorghum, Sudan-grass and maize. The causal fungus is carried on the seed and also lives in the soil on dead or decaying plant material. It may cause seed rot and seedling blight, especially in cool and excessively moist soil. Seedlings then can become infected readily and may either die or develop into stunted plants. Small reddish-purple or yellowish-brown spots usually develop on the leaves of infected seedlings.

The spots may join to kill large parts of the leaves, which then dry to the extent that severely affected plants look as if they have been burnt. A greenish, mould-like growth of spores develops in the centre of the leaf spots during warm, humid weather. The spores are spread by wind or rain and infect other leaves and plants. Under warm, humid conditions the disease may cause serious damage by killing all leaves before plants have matured.