Groundnut leaf rust

The characteristic orange-coloured pustules, the uredinia, appear first on the lower surfaces of the groundnut leaves. Uredinia then rupture to expose masses of reddish-brown urediniospores. Pustules may later appear on the upper surfaces of the leaflets opposite those on the lower surfaces of susceptible cultivars. In highly susceptible cultivars, secondary pustules may develop around the primary pustules. Pustules are usually circular, and range from 0.5 to 1.4 mm diameter. They may form on all aerial plant parts with the exception of flowers. Rust-damaged leaves become necrotic and dry up but remain attached to the plant. In the case of severe damage, plants have a burnt appearance.