Leek rust

Identifying Features
This fungal disease will cause bright yellow spots on the leaves and is more pronounced in long, wet spells. A mild attack of rust should not affect the plant, however, a serious infection can cause the leaves to shrivel affecting the overall crop yield.

Treatment
There is no cure for rust once the infection has settled. Ensure plants are not over-crowded as this will increase humidity and the likelihood of infection. Remove and destroy any badly affected plants. Don't grow alliums in the same spot for 3 years.