Rust Fungi

Fruiting bodies of Puccinia sessilis, 'Arum Rust', on the underside of a leaf of Wild garlic — a commonly foraged edible plant.

Rust Fungi (Order Pucciniales) are highly specialised obligate fungal parasites of plants, including many common agricultural crops. Over 7000 species are described, across 168 genera.

Infections may appear on any part of the plant (most often affecting leaves, stems, petioles, fruits, and flowers), resulting in yellowing of plant matter, galling, stunted plant growth, and the development of powdery yellow to brown coloured masses of spores. These infections are not often fatal to the plant, and generally have little effect on edibility of the host plant, though growth of the plant can be severely hindered and can still result in an altered taste and wider palatability.

Transmission of rust fungi occurs via the release of small spores from the fruiting bodies of the fungus, which can be transported by the wind, insect vectors, or water. These spores are incredibly specific to the infection of one group of host plants, not causing infection outside of these species.

Control

Rust fungi are incredibly difficult to treat, though some fungicides may be used to hinder infection. A spray of Sodium bicarbonate and water, or the application of powdered Sulphur to the plant can be beneficial to prevent the spread of spores.

The most effective method for removing rust is to cull infected plants, removing any rust covered matter and subsequently burning. Infected matter should not be composted, as spores can make their way into the soil, facilitating further spread of the fungus.

Gallery

• 
  Puccinia caricina on underside of Flowering Currant leaf
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  Flowering currant leaf underside, showing location of Puccinia caricina infection
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  Caeoma allii-ursini on underside of Wild garlic, partially disrupted by end of the leaf
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  Kuehneola uredinis on the stem of a Rubus sp. bramble
• 
  Galling on Common Nettle leaf, caused by Puccinia urticata
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  Pucciniastrum epilobii growing on American Willowherb, a garden weed
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  Blackened spore clusters of Phragmidium violaceum on the underside of a bramble leaf
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  Uromyces hyacinthi on a Bluebell leaf

See also

• Fungi
• Fungiculture
• Farming

References

This article uses material from the Wikipedia article Rust_(fungus), which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).