Common rust

It is recognised by the appearance of circular to elongate pustules scattered over both surfaces of the leaf. Pustules are powdery and cinnamon-brown in colour. They contain masses of spores (uredospores). Pustules can appear on any above-ground part of the plant, but they are most abundant on the leaves. With time the pustules split exposing the spores, which are spread by wind and initiate new infection. As maize matures, colour of spores in pustules change from reddish to black due to formation of teliospores (resting spores). The disease is spread by air transport.