rust

rust in botany, name for various parasitic fungi of the order Uredinales and for the diseases of plants that they cause. Rusts form reddish patches of spores on the host plant. About 7,000 species are known. Some grow entirely on one plant; others require two hosts, plants of two species, in order to complete their life cycles. Cedar rust, for instance, grows on cedar and on apple trees, needing both for development. Blister rust of pine grows on pines and either currant or gooseberry bushes. Black stem rust Puccinia graminis is one of the most destructive to wheat, rye, and other grasses; barberry is an alternate host. Rusts attack all cereal crops and many fruits, vegetables, forage crops, ornamental plants, and forest trees. Rusts are hard to eradicate; control measures include the use of rust-resistant varieties of seed and the elimination of alternate hosts in agricultural areas. Rusts are classified in the kingdom Fungi , phylum (division) Basidiomycota, order Uredinales.

rust A plant disease caused by a fungus of the class Urediniomycetes. The characteristic symptom is the development of spots or pustules bearing masses of powdery spores which are usually rust-coloured, yellow, or brown. Infected plants may also show distortions or gall-like swellings. Compare white rust.

rust A plant disease caused by a fungus of the class Urediniomycetes. The characteristic symptom is the development of spots or pustules bearing masses of powdery spores which are usually rust-coloured, yellow, or brown. Infected plants may also show distortions or gall-like swellings. Compare WHITE RUST.