Death caps now grow in San Diego County. Here's what to know before the rains

San Diego's mushroom season usually starts with the first real winter storms, and this year it follows the worst mushroom-poisoning season California has recorded. Between November 2025 and May 22, 2026, the state counted 50 amatoxin poisonings, 4 deaths and 4 liver transplants.¹ No cases had been reported in San Diego County as of late May 2026,^2,3 but the death cap, the species state health officials singled out, now grows here.^1,3

How bad was last season?

A typical California year sees fewer than 5 amatoxin poisonings.¹ The 2016 Northern California outbreak, until now the benchmark, had 14.⁴ Last season's patients ranged from 19 months to 84 years old and were treated in hospitals in 12 counties, from Humboldt to San Luis Obispo. People picked the mushrooms in neighborhoods, local and regional parks, nature preserves and at least one national park, and several dogs died too.² Food Safety News called it the largest wild mushroom outbreak in U.S. history.⁵

State health officials also warned that the deadly mushrooms were fruiting out of season in spring 2026, including in parts of Southern California, and said the risk was statewide.²

Death caps are already in San Diego County

As of October 20, 2026, iNaturalist holds 22 research-grade death cap (Amanita phalloides) records from San Diego County, dating from 2021. They come from Fallbrook, Escondido, Vista, Carlsbad, Encinitas, Oceanside, parts of the City of San Diego and Descanso, several of them under planted, non-native oaks. Ten were logged during the November 2025 to January 2026 season, and one came from a May 2026 flush.⁶

The County confirmed it in May: death cap and other amanita-containing varieties "can be found in San Diego County."³ They join the western destroying angel (Amanita ocreata), the county's long-established deadly mushroom, with 330 verifiable records, most of them from January through March under coast live oaks.⁷

The timing matters. About 68% of the county's fungus records fall between December and April, with January the peak month.⁸ That's when most San Diegans will find mushrooms in yards, canyons and parks this winter.

Why poisonings are rising

Times of San Diego reported in May that mushroom foraging is on the rise statewide, and that identification apps capable of labeling a death cap as edible are part of the problem.⁹ State and County health officials tell foragers to rely on local experts, not apps or websites, and to photograph and record where they picked anything.¹⁰

County Public Health Officer Dr. Sayone Thihalolipavan called the statewide numbers "unprecedented and tragic" and urged San Diegans to avoid "collecting and eating all wild mushrooms."³ In December 2025 he added: "Store-bought mushrooms are the safest choice."¹¹

What San Diegans should do this winter

• Follow the County's advice: don't collect or eat any wild mushrooms.³ Cooking, boiling, freezing and drying don't destroy amatoxins.¹
• Clear mushrooms from yards where children and pets play, especially after rain.¹⁰
• Call Poison Control at 1-800-222-1222 if anyone eats a wild mushroom, even with no symptoms. Amatoxin symptoms start 6 to 24 hours later and can fade before liver damage sets in.¹² For pets, call your vet or the ASPCA Animal Poison Control Center at 1-888-426-4435.³
• Learn from people who know. The San Diego Mycological Society runs free mushroom ID sessions before its public talks in Balboa Park.¹³

Our guide to wild mushrooms in San Diego County has the full list of local species to know, the symptom timeline and the rules on picking in parks. If someone is having a bad reaction to any mushroom product, our psilocybin safety guide covers when to call 911.