A popular edible mushroom, the golden oyster, is spreading rapidly through U.S. forests, outcompeting native fungi and threatening biodiversity, according to University of Florida researchers. Sold widely in markets including Florida, the fungus has appeared in more than 25 states in about a decade. Michelle Jusino, a forest pathology expert, urges growers to handle it responsibly to prevent further ecological damage.
Michelle Jusino, assistant professor of forest pathology at the University of Florida's Institute of Food and Agricultural Sciences, highlighted the risks of the golden oyster mushroom. With its bright yellow caps, it is a favorite for home cultivation and sale in grocery stores and farmers markets. However, Jusino warned, “The golden oyster mushroom may look harmless on a log, but it appears to be a strong competitor in the forest. It is associated with changes in the fungal community, reducing biodiversity and potentially affecting processes like wood decomposition and carbon cycling.” The spread stems from human activities such as buying, growing, and transporting the mushrooms, tracked through platforms like iNaturalist and Mushroom Observer. Records show expansion into over 25 states since the early 2010s, including Texas, the District of Columbia, Virginia, North Carolina, Alabama, and Louisiana. Jusino noted, “It is slowly marching south, which is really terrifying. In 2016, the mushroom was found growing in the wild in just five states, all in the Midwest and Northeast, but today I think fewer than 10 states east of the Mississippi river remain without records.” A field study on dead elm trees in Wisconsin, which Jusino helped design, found trees colonized by the golden oyster hosted fewer fungal species and an altered community compared to unaffected ones. Native fungi, some with ecological or medicinal value, were reduced. “We want to remind growers that not all cultivated fungi stay where we put them,” Jusino said. “Once released outdoors, even accidentally, the golden oyster mushroom can spread quickly and outcompete native species.” Researchers call for awareness, monitoring, and preference for native species to protect forest ecosystems amid the biodiversity crisis.