Rust

On leaves, the symptoms of U. beticola infection depend on the period of the growing season and the subsequent stage of the fungus. The spermogonial stage can be recognised by the appearance of honey-coloured sunken spots on the adaxial leaf surfaces in spring (Duffus and Ruppel, 1993). The aecial stage is marked by the development of yellowish-orange 'cluster cups' on the abaxial leaf surface (Duffus and Ruppel, 1993). 

The most obvious symptoms are at the uredial stage, when both sides of the laminae and petioles of the leaves are covered by russet-coloured pustules that erupt through the epidermis and are usually surrounded by a yellow halo (Hull, 1949). These pustules are the uredia, producing vast numbers of uredospores that accumulate as a russet-coloured powder in leaf depressions and crevices. On susceptible plants, the infection quickly progresses, causing the older leaves to wilt and die prematurely (Punithalingam, 1968). The telial stage of the fungus occurs in late autumn and is represented by the uredia becoming dark brown as the leaves senesce (Duffus and Ruppel, 1993).

On inflorescences, the symptoms are similar except that it is highly unlikely that spermogonial and aecial development would occur.

On seedlings, the spermogonial, aecial and uredial stages can be seen, but not the telial stage.