- Sclerotinia sclerotiorum (causal agent of white mold) can cause serious economic losses in snap bean production as well as many other crops. Spores are produced in apothecia (mushroom-like structures) that develop from over-wintering sclerotia in the soil. Sclerotia are long-lived, durable hyphal survival structures produced by the fungus and they can survive up to eight years between hosts. Recent cool, wet growing seasons have promoted white mold disease and Ocamb has observed white mold epidemics in a number of fields where disease exceeded 10% incidence (snap bean, bell pepper, cauliflower, winter squash, and experimental canola fields). Gray mold (Botrytis sp.) can also infect bean, but usually occurs at very low levels in fungicide trials (<0.5 % plant incidence) on the OSU-BPP Farm and its presence on a plant is usually preceded by white mold.