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Leek rust (Photo M. Garnett)




Onions and Leeks


Characteristic raised bright orange pustules visible on both sides of the leaves.


First appears from mid-summer to late autumn. Can only survive on `live` plant tissue. Spores dispersed by both wind and rain. Resting spores can be produced but it is thought that the majority of outbreaks come from host plants bearing disease on live tissue throughout the year.

Favourable Factors

Warm, dry conditions with high humidity.


Widespread and more commonly associated with leeks than onions but can be found on garlic and chives. Severe attacks reduce plant vigour.


Identification and Management of onion and leek diseases

Find out more information on the key disease threats to your onion and leek crop. For each disease you will find out the importance of the disease in terms of potential yield penalty, how to identify the disease in its early stages and our advice on the best control strategies.

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