Leek rust is a very common fungal disease of leeks, but also can affect onions, garlic and chives. The fungus causes bright orange, raised spots, pustules on leaves.
Quick Facts on Leek Rust
Common Name: Leek rust
Scientific Name: Puccinia allii (syn. Puccinia porri)
Plants Affected: Leeks, onions, garlic and chives
Main Symptoms: Bright orange pustules on leaves
Timing: Mid-summer until late autumn
What is leek rust?
Leek rust is a disease caused by the fungus Puccinia allii. Most important on leeks but also affects onions, garlic, chives and other Allium spp. The rust pathogen is comprised of genetically distinct sub-groups which differ in different parts of the world. In the UK onions are rarely severely affected, but rust can be serious on leek, garlic and chives. Most attacks occur from mid-summer until late autumn.
Control of Leek Rust
Non-chemical control Infection is worse on nitrogen-rich soils with low potassium, so take care with fertiliser applications Do not crowd plants, as this raises humidity and increases the likelihood of infection Dispose of all plant debris at the end of cropping Suppliers sometimes claim a degree of resistance for certain varieties, check the latest catalogues for those currently available