Cordyceps (Cordyceps sinensis) is known under many names, such as Dong Chong Xia Cao (caterpillar in winter, grass in summer), caterpillar mushroom, Ophiocordyceps sinensis, etc. It belongs to the Cordyceps genus which also includes other species, e.g. C. militaris, C. liangshamensis, C. gunnii, etc. (Nowadays, approximately 700 Cordyceps species are recognised). It’s an edible ascomytic parasitic fungus whose spores get stuck on the surface of the Thitarodes armoriacanus caterpillar. The caterpillar then becomes infested with the fungus and buries itself into the ground in order to enter the next developmental stage. Once there, it’s gradually consumed alive by the parasitic fungus. Cordyceps fills the caterpillar’s chitinous shell with its sclerotium which functions as the basis for the future mature fungus. The entire cycle can last up to 6 years. In the summer months of the final year, the fungus uses mycotoxin of its own making to ultimately kill the caterpillar, causing its head to literally sprout a head-like shape, known as stroma. Stroma is red-brown in colour and grows up to be 8‒10 cm. These formations grow spores which are then released into the environment in order to infect new butterfly larvae.
Cordyceps grows more than 3,500 metres above the sea level, primarily in the Tibetan mountains, in the Chinese provinces of Sichuan, Yunnan, etc., or on plateaus. It’s picked between April and August. Unfortunately, it’s rarely found in the wild as its appearance has allegedly dropped by 90% in the last 25 years. This of course increased its market value which is why the fungus can be grown artificially as well. Pseudo-caterpillars from the Tibetan Plateau are the highest quality of all. The price for 4 pieces can reach 100 USD, with 1 piece. weighing about 0.5 grams, i.e. costing ca 500 CZK. Since the demand and price is high, other Cordyceps fungi can be now found on the market, e.g. the militaris variety which is passed-off as Cordyceps sinensis (CS). Although militaris has similar effects, it can’t replace CS. In 2001, DNA sequencing made it possible to identify the CS-4 stem (Paecilomyces hepialy) which has been sold under this name since 2005. CS-4 is considered to be the most effective stem of cordyceps’ mycelium, grown artificially, i.e. with substrate. Originally, soya was used as substrate but it was later replaced with rice as there was a risk of using genetically modified soya, or of possible soya allergies, not to mention the link between soya and breast cancer, etc.
So why is cordyceps in such a high demand? Mainly due to its effects on animal and human health. The fungus has been used successfully by traditional Chinese and Tibetan medicine. Surviving ancient stories describe how yak shepherds discovered its beneficial effects. The animals which grazed both on grass and cordyceps were more vital, stronger, and healthier, as well as more potent. Of course, this encouraged shepherds to start using the fungus themselves. The written historical records, a part of Chinese herbals, at our disposal come from ca 620 AD. The Western world didn’t “discover” cordyceps until 1726 when it was introduced to experts during a mycology conference in Paris. Although the mushroom was mentioned in mycology encyclopaedias, its effects were unknown. This changed more than 200 years later. In 1964, cordyceps was included among medicinal plants of the modern Chinese pharmacology.
EU legislation prevents us from making health claims about fungi and herbs. You can find more information about fungi and herbal blends online, for example on tcmencyklopedie.cz.