ABSTRACT
The pathogens responsible for smut and rust diseases are members of the kingdom Fungi and the phylum Basidiomycota, and are placed in the orders Ustilaginales and Uredinales, respectively. Those orders differ from most other Basidiomycota in not having their sexual reproductive spores (basidiospores) borne on or in fruiting bodies, as in mushrooms and puffballs. Rather, their basidiospores are borne on specialized germ tubes (basidia) produced on the germination of thick-walled, typically dormant, resting spores
(teliospores). Smut fungi can be cultured on artificial media much more easily than the rusts. However, as pathogens in nature, both the smuts and rusts function as obligate parasites, that is, they require living host tissue as a nutrient source. Both types of pathogens cause important plant diseases, but rust fungi attack a much broader host range and worldwide are far more important economically than are the smuts.
