Q. I am seeing a lot of mushrooms in my yard that were never there before. They look very similar to the mushrooms I see for sale in the store. Are they edible? Why are there more mushrooms this year?
A. There are thousands of species of mushrooms worldwide. About 100 species of mushrooms found in the wild are poisonous to humans, and 15 to 20 mushroom species are lethal when ingested.
Every year, more than 9,000 cases of mushroom ingestion are reported to the American Association of Poison Control Centers. Children younger than 6 account for a majority of these cases. Even though the number of actual deaths from mushroom poisoning in the U.S. is small, my advice is to mow over the mushrooms or collect them and throw them away with the trash. We cannot identify mushroom species at the County Extension office.
No simple rules exist for distinguishing edible mushrooms from poisonous mushrooms, but virtually all mushrooms one might find in a yard are poisonous to some degree. Symptoms of mushroom poisoning can be delayed for up to 12 hours – or even days. There is no cure for mushroom poisoning.
Some people can even have allergic reactions to eating safe mushrooms, and some are only poisonous if eaten in large quantities. Some mushrooms are poisonous when raw but become harmless when cooked. Some mushrooms are poisonous only if consumed with alcoholic beverages. Some mushrooms that are edible when fresh and young become poisonous when they age, are hit by frost or simply decay. Some mushrooms, for unknown reasons, are poisonous in one part of the country, are not poisonous in another.
Cool, wet weather promotes mushroom growth. Many times mushrooms feed on the organic matter left when a tree is removed in a landscape. Check your yard for mushrooms before letting young children and pets out to play. Teach children not to taste or even touch any outdoor mushrooms.
Unfortunately, many mushrooms are difficult to identify even for a trained mycologist – a biologist trained in the study of mushrooms. In some states there are mycological clubs or societies that lead tours and conduct seminars on how to correctly identify mushrooms. The Internet is crawling with experts who claim to be able to help people identify mushrooms.
Remember – all its takes is the ingestion of one deadly mushroom to kill a person.
It is important to call a doctor immediately if a suspect mushroom is eaten, especially with small children. Just because a person has no immediate symptoms does not mean everything is OK.
Call the Poison Control Center if you even suspect a mushroom has been ingested, and save a sample of the mushroom to take with you to the doctor.
Some people suffer liver failure after eating the wrong mushrooms. If no liver is available for an emergency transplant, the patient could die.
Excellent mushroom information is available at the University of Missouri Extension at http://mdc.mo.gov/discover-nature/outdoor-recreation/mushrooming/poisonous-mushrooms