Death cap mushroom (Amanita phalloides) in grass. (Courtesy of Paul Kroeger/Beaty Biodiversity Museum)
The Idaho Division of Public Health has confirmed the discovery of death cap mushrooms, which can be harmful to people and pets, in Idaho, according to a press release from the Idaho Department of Health and Welfare.
An amateur mycologist spotted the mushroom under an oak tree in a Boise neighborhood, and DNA testing by a laboratory pathologist confirmed the identification, according to the release. The health department warned Idahoans that the poisonous mushrooms may be present and undetected in other areas.
Death cap mushrooms are highly poisonous and cause most deadly mushroom poisonings worldwide, according to the release.
“They can look like edible mushrooms (such as paddy-straw mushrooms or puffballs), but eating as little as half a mushroom cap can kill an adult,” the release said. “A small portion can kill a dog. Cooking does not make the death cap mushroom safe to eat.”
Early symptoms of death cap mushroom poisoning are persistent and violent vomiting, abdominal pain and profuse, watery diarrhea six to 24 hours after eating the mushroom, according to the health department. These symptoms generally last a few hours, after which there is an apparent recovery with no symptoms for a few days. Then jaundice, loss of strength, coma and death can occur from liver failure and kidney failure.
Early treatment is critical to decrease the chance of dying or needing a liver transplant, according to the release.
According to the Idaho Department of Health and Welfare, when in doubt, throw wild mushrooms out
Death cap mushrooms are not the only poisonous mushroom in Idaho. Generally, the health department recommends that Idahoans should not eat any wild mushroom that have not been identified by an expert or throw them out. See a wild mushroom identification and buying guide at https://publicdocuments.dhw.idaho.gov/WebLink/DocView.aspx?id=21978&dbid=0&repo=PUBLIC-DOCUMENTS.
What to do for potential mushroom poisonings
If you or your child has eaten an unidentified wild mushroom, call the poison center at 800-222-1222 right away, call your health care provider or to go the emergency room.
If your pet has eaten a wild mushroom, call the ASPCA Animal Poison Control Center’s 24-hour hotline at 888-426-4435 or your veterinarian or veterinary emergency clinic.
What to do if you find them in your yard
Death cap mushrooms are found near imported trees in gardens, parks, and urban areas but can spread to wild areas over time, according to the release. In other regions, death cap mushrooms appear in late summer through December, or year-round. Seasonal risk in Idaho is unknown, the release said.
To help avoid spreading death cap mushrooms to other areas, remove the mushrooms from your lawn before mowing. Grasp the mushroom low on the stalk and pluck it from the soil.
There is no evidence that hand contact with death cap mushrooms is dangerous, but wearing gloves will protect your skin from germs in the soil. Wash your hands thoroughly after touching the mushrooms or surrounding soil.
Dispose of the mushrooms in the garbage. Do not compost at home or put in the city compost cart. Do not put death cap mushrooms in wood chip containers or trucks. Clean and disinfect garden tools after using them around affected trees. Spraying will not eradicate death cap mushrooms.
The public is encouraged to submit photos of death cap mushrooms to iNaturalist.org to help track the spread of this mushroom in Idaho, the release said.
For more information about wild mushrooms, see the Southern Idaho Mycological Association, https://idahomushroomclub.org or the North Idaho Mycological Association at https://www.facebook.com/IdahoWildMushrooms/.
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