Researchers identified a new species of Trichoderma fungus that causes green mold disease in cultivated medicinal mushrooms, particularly Ganoderma sichuanense. Using DNA analysis and genetic comparison, they showed that this new species belongs to a group of Trichoderma fungi that are close relatives of species used for controlling plant diseases. The study suggests this fungus might have potential as a biocontrol agent while currently being problematic for mushroom farmers in China.