Rust - Uromyces fabae

Rust is associated with warm (optimum 18oC) and wet weather (optimum 18 hours leaf wetness), especially towards the end of the season and is more common in spring beans than winter beans. Control of rust produces variable results ranging from none to up to 50% yield increase, probably due to the late period over which it infects the crop. Late infections of rust (once the seeds have reaches maximum weight) are often used as a form of desiccant and left uncontrolled.