Rust of pea
How to get rid of rust of pea
The fungus mainly attacks spurge plants. The pea serves as an intermediate host. Leaves show light and dark brown thickenings filled with fungal spores. This leads to deformation of the leaves, a reduction in growth, but hardly any reduction in yield.
Treatment
The most effective control is to offer the fungus a maximum of one host plant, as it needs two (pea, vetch, field bean and spurge plant)
Michal Maňas, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons