EXPLAINED: The (worrying) popularity of caterpillar fungus

By now the army of scavengers has retreated from the high hillsides of the eastern Tibetan plateau, their bounty in hand. Harvest season for yartsa gunbu (དབྱར་རྩྭ་དགུན་འབུ།), or caterpillar fungus, typically runs from May to July, when winter snows have receded and thousands of rural, ethnic Tibetans can prospect for what’s also known as “soft gold.” 

It’s hard to overstate the importance these few weeks hold for the people who climb the steep slopes. Collecting caterpillar fungus —  which is used to treat a variety of ailments — can account for as much as 90% of a rural family’s annual income. 

But high demand has spurred overharvesting, making it harder to find the fungus in its natural environment. Climate change poses another challenge. Warmer temperatures on the high plateau are reducing the length of winter, a critical time for yartsa gunbu.

Now a new threat is emerging, sources inside China say: artificial varieties designed to fill the gaps between supply and demand, in the form of either cultivated fungi or fake products altogether. Although Chinese authorities have tried to regulate the sale of cultivated fungus, interviews with Tibetans and online videos that attract tens of thousands of viewers say imposters have infiltrated the market.

“It will definitely jeopardize the lives of thousands of Tibetan herders and farmers whose income depend on the wild yartsa,” said Lobsang Yeshi, who has practiced traditional Tibetan medicine at Men-Tsee-Khang in Dharamshala, India, for the past 20 years. 

What is caterpillar fungus and where does it come from?

Yartsa gunbu translates to “summer grass, winter bug.” The Ophiocordyceps sinensis – its scientific name – releases spores that sink underground and infect the larvae of ghost moths, so called for the white color of males. The yartsa gunbu takes over, commandeering the caterpillar’s nervous system, consuming its organs and finally, in spring, emerging from its head as a brown stoma at altitudes of greater than 13,000 feet (4,000 meters). Its methods have drawn comparisons to the fungus that stars in the HBO hit zombie series, “The Last of Us.” Harvested intact, it’s about the length of a little finger and shaped like a caterpillar with a stem attached. 

Yartsa gunbu is found primarily in the Himalaya mountains and the Tibetan plateau. The Yushu Tibetan Autonomous prefecture in Qinghai province, east of the Tibetan Autonomous Region, is a particularly good place to look. Thousands of its residents set up makeshift camps from which they hike into the thin air.

The annual harvest is reportedly around 300 million fungi that can cost $7 a pop or more, leaving a multi-billion dollar market. 

What is caterpillar fungus used for?

Yartsa gunbu has been used in Tibetan and Chinese traditional medicine to treat heart, liver and lung ailments. More recently, it acquired a reputation for improving sexual stamina in men and women. (“Himalayan Viagra” is another moniker.) Studies have shown possible benefits, though scientists say more clinical research is needed.

Users consume yartsa gunbu by brewing it with hot water similar to how tea or herbal infusions are prepared, or chewing it as it comes. Some put it in soups and other recipes. Lesser specimens are ground into powders.

Why are people growing a fungus ? 

Pluckers like to pick the fungus before it releases spores, limiting its ability to reproduce and leading to its population decline. China has encouraged the development of cultivated yartsa gunbu, and one company has reportedly solved the puzzle, synthetically growing the O. sinensis fungus found in the wild. 

But some individuals are trying to cultivate fungus varieties on their own. That, fungus traders say, has undercut prices and, because the buyer’s remain suspicious of its medicinal properties, consumer confidence, several sources told RFA. 

In Guangzhou, a major market, “there is a hesitancy of customers in buying because of too much artificial fungus in the market,” one trader said. A Tibetan living in Qinghai province said prices have dropped nearly 20% this year. 

In New York, a retailer said he can still sell a single piece of wild fungus for $14, but “there are a lot of fake and cultivated yartsa” undercutting the business, he said. “Nowadays, people are selling thousands of artificial yartsa online per day, as well as in shops, jeopardizing the original yartsa business,” he said.

Studies have shown that cultivated fungus can replicate the chemical compounds of natural varieties, though there are differences. 

What is China doing to protect the market?

Chinese authorities seem to be aware of the financial risks to some of their poorest populations. 

In April, the Chinese government in Qinghai, tried to control the artificial plantation of yartsa gunbu. But a trader in Nagchu, Tibet Autonomous Region, an area that historically has been among the best for finding wild yartsa gunbu, said enforcement has been lax.

“Chinese authorities have come out with a lot of rules saying that the artificial fungus is banned,” the trader said. “But the on-ground reality is that the Chinese authorities are not strictly monitoring or stopping the sale of artificial fungus. And this is making it tough for us to sell the real fungus.” 

Lobsang from RFA Tibetan contributed to this article. Edited by Jim Snyder and Boer Deng.