He specialized in the breeding of Hevea brasiliensis for rubber production. Natural rubber, coming from latex of "Hevea brasiliensis", is mainly poly-"cis"-isoprene. This is the first time that the pathogen was found instead of "Hevea brasiliensis". It produces a yellowish latex of inferior quality to "Hevea brasiliensis". Yersin introduced rubber trees ("Hevea brasiliensis") to the property. Plantings of para rubber, the tree "Hevea brasiliensis", are usually called plantations. Currently the only available commercial source of natural rubber is the Hevea plant (Hevea brasiliensis). The larvae feed on "Hevea brasiliensis", "Theobroma cacao" and "Santalales" species.