Rust

Rust is not a common disease, but can be fatal in a severe attack during summer.

Symptoms
Orange spores can be seen on the surface of foliage.

Treatment
Diseased leaves should be cut from the plant and burnt. Common fungicides containing sulfur generally halt the progress of rust.

Prevention
Avoid watering from above, water the base of plants or use a soaker hose. Do not grow leeks or onions on affected land for 1 year.