How Mushrooms Can Save the World

How Mushrooms Can Save the World

By then, Stamets was obsessed with the possibilities of what he called “mycorestoration,” a nascent field encompassing his own and other researchers’ work in mycofiltration, mycoremediation, mycoforestry and mycopesticides (most of which are terms he coined). He began amassing a genetic library of hundreds of mushroom strains — gathered on hikes through the old-growth forests of the Northwest and on trips to Europe, Asia, South America and Australia — that could be used for environmental as well as medicinal healing.

The EPA asked Stamets to help the Coast Guard find ways to clean up waterborne oil spills. In response, he invented the mycoboom, a burlap tube filled with oyster mushrooms designed to break down petroleum while floating on a slick or barricading a beach. Battelle researchers tested his fungal strains against neurotoxins and found one potent variety of psilocybin mushroom highly effective at breaking down VX nerve gas. 

Stamets collaborated with the Washington State Department of Natural Resources on another successful field experiment, planting mushrooms on old logging roads to prevent silt and pollutants from clogging streams. He improved crop yields on farms and sped up reforestation in woodlands by adding mycorrhizal fungi to soil. In one case he planted broccoli together with elm oyster mushrooms; in another, he dipped Douglas fir seedlings into a slurry of puffball mushroom spores. 

He invented the Life Box, a cardboard carton impregnated with tree seeds and symbiotic fungi. After use (for shipping shoes bought online, for example), the box could be torn apart and planted to replace the trees used in its manufacture.

But the invention with the greatest immediate impact on Stamets’ own environment grew out of his relationship with herbal medicine practitioner Carolyn “Dusty” Yao, which began in 1997 after his first marriage fell apart. (Stamets and Yao were married, with Andrew Weil officiating, four years later.) When Yao moved in, she was dismayed to find that Stamets’ old farmhouse was infested with carpenter ants — attracted, ironically, by a white-rot fungus that was crumbling the floor joists. Stamets, who had ignored the problem for years, promised to take care of it. 

He wanted to use a natural pesticide that was nontoxic to humans; unsurprisingly, he began looking for one derived from fungi. He knew that a few mold species could infect insects with their spores, killing them in the process. (In some cases, a tiny mushroom pops through the corpse’s skull.) Yet existing mycopesticides worked poorly against social insects, which could smell the spores and stop workers carrying them from entering the nest. 

Stamets smelled a challenge. 

He sent away for a sample of Metarhizium anisopliae mold, known to kill termites and carpenter ants when its spores are sprayed on them directly. His idea was to train the fungus, which normally produces spores nonstop, to hold off until the ants had carried it into the nest. In its pre-sporulating form, he thought, the insects might be attracted to Metarhizium as a source of nutrition. Once they ate it, the mycelium would consume them in return.

When Stamets cultured the mold in his lab, a white circle of mycelium spread over the petri dish from the point of inoculation; it was soon covered with green spores. He transferred bits of the mold to other dishes, where they reproduced for several generations. Eventually, white stripes emerged amid the green in one dish, where the mycelium (perhaps due to a damaged gene) was lagging in its spore production. He then took some of the white material and cultured it over many more generations, breeding a mutant strain of Metarhizium whose sporulation cycle was delayed for days or longer.

Stamets grew his developmentally delayed mycelium on rice. When it was ready, he put a teaspoon of the spawn on a dollhouse dish belonging to his then-teenage daughter, LaDena, and placed it on the kitchen floor. That night, she ran to his bedroom yelling, “Wake up! You’ve got to see this!” The dish was swarming with ants, which were carrying grains of myceliated rice back inside the walls. Two weeks later, the house was ant-free, and remained that way from then on. After the insects died, Stamets hypothesized, the smell of their moldy bodies warned others away.