Most infested soils are in home gardens. Wart disease presents biological, social, and legislative problems. This pamphlet attempts to put some of these problems in perspective. The major symptom of wart disease is a gall at the base of the potato stem, or the haulm, The gall, which is white when under ground, and black when decaying, may be as small as a pin or as large as a fist. Its surface is rough and corrugated-warty in appearance.
Severe infestations destroy the potato crop by preventing tuber production.
This fungus, which characteristically thrives in very wet conditions, belongs to a family of fungi that generally inhabit freshwater ponds. When the surface of a gall is examined with a hand lens, the fungus appears as a myriad of tiny brown dots, which are actually resting spores. The gall eventually decays and turns black, releasing these spores into the surrounding soil. Resting spores are known to live for 40 years of more in undisturbed soil, their longevity contributing to the wart disease problem. When the resting spore germinates, it releases hundreds of tiny swimming spores into soil water.