Russian olive is a significant invasive weed in North America but is perceived as a useful and attractive tree by some stakeholders. It is especially a problem in western parts of the USA where it affects many natural habitats, altering the ecosystem and its functions. Biological control is a useful approach in such circumstances because scientists can look for natural enemies that damage reproduction, and thus future spread, without damaging established trees.
Common tansy is an aromatic Eurasian plant species with a long history of use as a medicinal herb. Introduced for this purpose to North America, it has since become invasive. One reason for this could be the absence of the natural enemies that keep it in check in its area of origin. CABI has been tasked with identifying specialist natural enemies from Eurasia that can be introduced into North America as biological control agents.
Russian knapweed is one of several invasive plants of rangelands that arrived in North America as a seed contaminant in the 19th century, in this case from Asia. Biological control is often a good approach for these plants, but a nematode species introduced in the 1970s proved ineffective against Russian knapweed. Funded by a US and Canadian consortium, CABI has been tasked with researching new biological control agents for introduction, some of which are already showing promise.