Poisonous Mushrooms in Garden Soil

Most Common Poisonous Mushroom

• The mushroom responsible for approximately 90 percent of fatalities is Amanita phalloides, a plain-looking mushroom often mistaken for edible Volvariella and Coccora species. Volvariella varieties, also known as paddy straw mushrooms, are found in Asia, while Coccora species live along the Pacific Coast. Amanita phalloides is a pale mushroom with a slender stalk and slightly dome-shaped cap. Other, usually less deadly species, that have toxins similar to those found in Amanita phalloides belong to the genuses Lepiota, Galerina and Conocybe.

Mushroom Toxins

• Amanita phalloides has phallotoxins and amatoxins, which are complex polyptides. While phallotoxins are poisonous if injected -- as confirmed by lab experiments -- amatoxins are poisonous if swallowed. Amatoxins attack the liver, intestines and kidneys, with severe intestinal flulike symptoms appearing between six and 36 hours after ingesting, though 10 to 12 hours is most common. After a few days, symptoms subside, only to present again as liver and kidney failure. Coma and death follow.

Mushroom Poisoning Symptoms

• Physicians often have difficulty diagnosing mushroom poisonings until it is too late because victims do not always associate their symptoms with eating the fungi, symptoms appear several hours to days after ingesting and then when signs do manifest, they mimic an intestinal infection or the common flu. The general rule of thumb is that the longer symptoms take to manifest, the more dangerous the poisoning. Less poisonous species often make their victims sick within a few hours, but rarely kill them. If you experience symptoms within a few hours or days of ingesting wild mushrooms, contact a physician immediately.

What to Do With Garden Mushrooms

• Since there is no simple test to identify poisonous mushroom species -- and since the most fatal species look a lot like edible varieties -- the University of California Integrated Pest Management program advises to never ingest wild mushrooms without the help of an expert specifically trained to identify them. Pick and discard mushrooms as soon as you see them and make sure to keep children and pets away from them at all times.