of uncertain application (probably Ascomycota) Rhizoctonia zeae = Waitea zeae (Corticiaceae) Habitat and distribution Species are saprotrophic, often occurring in soil and producing basidiocarps (fruit bodies) on dead stems and plant detritus. They are also opportunistic plant pathogens, with an almost unlimited host range, and have been isolated from orchid mycorrhiza. Distribution appears to be cosmopolitan. Economic importance Rhizoctonia solani causes a wide range of commercially significant plant diseases. It is one of the fungi responsible for Brown patch (a turfgrass disease), damping off in seedlings, as well as black scurf of potatoes, bare patch of cereals, root rot of sugar beet, belly rot of cucumber, sheath blight of rice, and many other pathogenic conditions. Rhizoctonia oryzae-sativae causes 'aggregate sheath spot' and 'sclerotium' disease of rice. The subtropical Rhizoctonia noxia causes 'black rot' of coffee and other foliar blights, whilst Rhizoctonia theobromae causes 'vascular-streak dieback' of Theobroma cacao (cocoa tree). In Europe, Rhizoctonia butinii causes web blight of spruce. An efficient conversion of tryptophan to indole-3-acetic acid (IAA) and/or tryptophol can be achieved by some species in the genus Rhizoctonia. References External links Index Fungorum Cantharellales Fungal plant pathogens and diseases Agaricomycetes genera