Puccinia (rust) on 9-week-old garlic plants

Puccinia (rust) on 9-week-old garlic plants

© Downtowngal

Type: Diseases

Rust (Puccinia alii)

This fungus lives within the leaf, developing the slot-shaped, raised pustules that give its name from summer onwards. There tend to be leeks (and other alliums) in the ground for much of the year, so the airborne spores it releases can usually find a living host to spread to. Humid conditions and dry soils seem to encouage infection. Although it does affect vigour, it is not usually too serious in vegetables as it has very little effect on the edible parts of the plant.


  • Rusty (yellow, brown or orange) spots and blotches on leaves
  • In severe infections, leaves can shrivel and die

Prevention & control

  • Grow resistant varieties
  • Good long rotations
  • Avoid nitrogenous fertilisers, particularly on low potassium soils, as this encourages lush, weak, susceptible growth
  • Lift and eat infected plants as soon as they are ready, burning affected leaves
  • Avoid the humid conditions caused by overcrowding and keep weeds under control
  • Keep the soil moist with regular mulching
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