Onion Rust
Onion leaf showing orange rust spores (Puccinia allii)
Scientific Classification
Kingdom: Fungi
Division: Basidiomycota
Class: Urediniomycetes
Order: Uredinales

Rusts are diseases caused by fungal pathogens of the order Uredinales .The taxonomy of Urediniomycota is complex and the darker coloured smut is often mistaken for rust. About 2000 species are known. Rusts are so-named after the reddish rusty looking spores and the disease is usually noticed after the first rains. The group is considered as one of the most dangerous pathogens to agriculture and horticulture. Cereal crops can be devastated in one season and trees that get infected in the main stem within the first five years, invariably die.[1] The disease is known as a foliar disease but it can affect a variety of plants; leaves, stems, fruits and seeds. It is not a common disease, but can be fatal in a severe attack during summer.[2]



Orange spores can be seen on the surface of foliage.


Diseased leaves should be cut from the plant and burnt. Common fungicides containing sulfur generally halt the progress of rust.[3]


Avoid watering from above, water the base of plants or use a soaker hose.[3] Do not grow leeks or onions on affected land for 1 year.



  1. Conrad, J. (2009). Rust Fungi. [ttp:// The Backyard Nature Website]. Retrieved: 2010-08-06.
  2. Hessayon, D.G. (2009). The Vegetable & Herb Expert. Transworld Publishers, London. p. 75. ISBN 9780903505468
  3. a b Grunert, J. et al. (2009). "Common Plant Diseases". Love to Know. Retrieved 2010-07-17.
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