The cost of a rare traditional Chinese medicine used to treat fatigue, fight cancer and boost sex drive has skyrocketed in the past 10 days because of the Yushu earthquake, vendors said.

?People bargain at a market in Xining, Qinghai province, for caterpillar fungus. The price of the precious fungus soared after the Yushu earthquake

Cordyceps sinensis, colloquially known as caterpillar fungus, is the result of a parasitic relationship between fungus and moth larvae.

It is valuable because of its rareness, produced naturally in the wild at altitudes of between 3,000 and 5,000 m on mountains close to the snowline.

The main producing areas in China are in Tibet, Qinghai and Sichuan.

Of the three, Qinghai produces the most and Yushu, which was hit by a 7.1-magnitute earthquake on April 14, is the major caterpillar fungus area in Qinghai.

"The price in Qinghai, where we purchase our caterpillar fungus, has already soared," said Bao Chengzhang, sales manager of a company selling caterpillar fungus in Beijing.

"High-quality fungus has increased by 20,000 yuan per kg, whereas low-quality fungus has increased by 10,000 yuan per kg," he told METRO.

He said the massive price rises in Qinghai have not yet filtered down to transactions in Beijing, but they will.

"It is the slack season now, which is the same as every year," added Chen Xia, a shopkeeper who sells caterpillar fungus in Ping'an Avenue.

"I believe the price will rise to a historic high this year," said Bao. "The price mainly depends on the volume of available fungus in the market, which I think will decrease soon."

According to Bao, people from other parts of Qinghai travel to Yushu each year during May and June to search for the fungus.

However, this year, the harvesters will be stopped from getting into the caterpillar fungus-producing hotspot of Yushu by the government because the area is cordoned off due to instability following the earthquake.

Meanwhile, residents in Yushu will be busy rebuilding their homes and communities and have little time to harvest the fungus, meaning this year's crop will be significantly smaller than in the past.

Bao predicted the price rise will trickle down to consumers in Beijing soon and explained that it was already a very expensive product.

"Thirty years ago, we couldn't even sell it out in Qinghai for 25 yuan per kg," said Bao. "But now, in Beijing, high-quality caterpillar fungus is worth around 200,000 yuan per kg."

The high cost of the fungus, coupled with difficulty in storing it and uncertainty about its medicinal effects, have put some people off buying it.

"I will stop using it if the price becomes too high in the future," said Jiang Wei, a businessman who has been taking caterpillar fungus for two years as a health supplement.