Helicobasidium is a genus of fungi in the subdivision Pucciniomycotina. Basidiocarps (fruit bodies) are corticioid (patch-forming) and are typically violet to purple. Microscopically they have auricularioid (laterally septate) basidia. Asexual anamorphs, formerly referred to the genus Thanatophytum, produce sclerotia. Conidia-bearing anamorphs are parasitic on rust fungi and are currently still referred to the genus Tuberculina.

Species are opportunistic plant pathogens, causing violet root rot of root crops and other plants of economic importance. The name "violet root rot" refers to the dark purple colour of the mycelial mats formed on the infected plants, usually at or below the soil line. It can cause total rot and structural failure of roots and subterranean storage organs. Impact of violet root rot on crop loss is often due to stunting of above ground plant growth and decreased vigour, and in extreme cases, whole plant death. It does not directly infect above ground organs. Violet root rot can also damage or cause the death of subterranean storage organs such as potato tubers or carrots.

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