Giving dyer’s woad the blues
Dyer’s woad is an ancient source of blue dye and was grown as a textile dye crop in Europe and Asia for centuries. It was introduced to North America by early colonists, but escaped cultivation. Today, it is recognized as a serious weed in the western USA. One reason for its impact is the absence of the natural enemies that keep it in check in its area of origin. CABI is searching for specialist natural enemies in Europe that could potentially be introduced for its biological control.
Exploring options to control Canada thistle
Despite the name, Canada thistle’s natural home is Eurasia. It has spread throughout the temperate world to become one of the worst weeds in rangeland and crops. One reason for this is the absence of the natural enemies that attack it in its area of origin. In North America six insect natural enemies have been introduced as biological control agents to try to control the weed but they have had little impact. CABI has been investigating whether disease-causing fungi might be the answer.
Controlling swallow-worts the sustainable way
Swallow-worts (Vincetoxicum nigrum and V. rossicum) are Eurasian plants that have become invasive in North America. The overall goal of the project is to identify specific natural enemies that can be introduced to North America as biological control agents for swallow-worts.
An old problem revisited: biological control of toadflaxes
Native to Europe, toadflaxes were introduced to the USA and Canada over 100 years ago as ornamental plants. They now occur over much of temperate North America and are declared noxious in eight US states. CABI identifies specific natural enemies that can be introduced into North America as biological control agents to reduce the vigour, density and spread of this invasive plant.
Stemming the spread of Russian olive
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.
Tackling common tansy in North America
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.