Plant Pathogenic Rust Fungi
General Information
Rust fungi are highly important and damaging to commercial cropping and are very common throughout the world. They are the largest group of fungal plant pathogens known, and more than 7000 different species have been documented. The rusts received their common name from the fact that some species have a reddish spore stage during the eruption of fruiting bodies on the host plant, which resemble the colour of corroded metal. There is wide diversity among rusts, and over 4000 species have been found both in wild and cultivated plant populations. Many are obligate plant parasites on a wide range of crop plants including cereal grains, legumes and trees. This means that they can be very dangerous to agricultural and horticultural crops, as well as wild plants, causing reduction in yield or even the death of their host plants. They can normally be controlled by breeding crops for resistance, coupled with fungicide treatment. Most rust fungi are highly host-specific, and the parasitised host plant is important to consider in order to properly identify the rust species. Many rusts are heteroecious, having 2 or more hosts, and have a very complex life cycle that can involve up to 5 spore stages.