Some have described it as "old socks and sex": the pervasive smell of truffle that comes into season in the southern hemisphere in winter and has put Manjimup on the world culinary map as a producer of one of the most expensive foods.

After more than 3000 years of consumption, it's still an enigma, the nubby fruit of the fungus Tuber melanosporum, known as the Perigord black truffle after the district in Dordogne, France.

France, Spain and Italy are the biggest growers in Europe, where truffles can grow naturally underground along the roots of oak and hazelnut trees, but commercial production can be a tricky undertaking, involving injecting spores into host trees in a truffiere (truffle bed).

The WA harvest is underway now, led by teams of trained dogs with sensitive noses to detect the earthy scent of buried treasure that has recently had its DNA mapped by European scientists, who found volatile sulfur compounds and aldehydes were among the molecules that produced the truffle's heady aroma.

They also found truffles had a sex life, which may affect how trees are inoculated in the future to ensure successful propagation.

Former CSIRO scientist Nicholas Malajczuk, who helped establish WA's first black truffle farm in Manjimup more than 10 years ago and runs truffle consultancy Treetec in Bunbury, will give a talk on the secret life of black truffles at 11am on Saturday at the Mundaring Truffle Festival.