The death cap mushroom (Amanita phalloides) moves to a native tree in Victoria, British Columbia

Abstract

Amanita phalloides (Vaill. ex Fr.) Link, the death cap mushroom, is an invasive ectomycorrhizal fungus in North America that was inadvertently introduced from Europe. Death cap mushrooms are highly toxic and have caused three recorded poisonings in British Columbia (BC), including one recent death. In BC, these mushrooms fruit mostly in urban environments in the greater Vancouver and Victoria areas under planted exotic broadleaf trees. In California, A. phalloides was demonstrated to also form ectomycorrhizas with a native oak species. Here we report that A. phalloides forms ectomycorrhizas with Quercus garryana, which is BC’s only native species of oak, and can fruit in association with this tree host. If death cap mushrooms spread in Q. garryana habitat, the risk for serious mushroom poisoning will increase, and mushroom harvesters, the medical community, and park managers will need to be made aware of this increased risk.