Tree of heaven, Ailanthus altissima, is a deciduous tree native to north-east and central China and Taiwan. It was brought to Europe and North America as an ornamental, but became invasive and is now an invasive species of concern in many countries, including Canada. Once established, tree of heaven is difficult to control, with mechanical and chemical options being limited and expensive. Since 2020, CABI has been working with partners to coordinate options for biological control of tree of heaven in Canada.
Parrot feather, Myriophyllum aquaticum, is a very popular garden and ornamental plant and has a long history of invasion worldwide. It was first recorded in Canada in 1980 from British Columbia and has since been recorded in the Lower Mainland and in the USA. Parrot feather forms dense impenetrable mats which affect stream flow, resulting in reduced native species’ richness at local scales, reduced water quality and habitat quality for fish and wildlife, and impacts on human activities. Due to the negative impacts, management of this species is required and a sustainable option is biological control. A biological control programme against parrot feather is already well-developed in South Africa and this project aims to investigate the potential for use in Canada.
Japanese knotweed is a highly invasive weed that impacts severely on native biodiversity and local infrastructure in its introduced range. Whilst chemicals are currently used to control the weed, this approach is costly and unsustainable. Biological control is an alternative method. The damaging leaf-spot fungus, Mycosphaerella polygoni-cuspidati, which attacks the plant in its native range was found not to be suitable as a classical biocontrol agent. However, the pathogen is considered to hold potential as a mycoherbicide. The aim of this project is to undertake proof-of-concept research into a potential mycoherbicide, in collaboration with the private industry.
The spotted lanternfly is an Asian polyphagous pest that feeds on more than 70 plants by sucking the sap out of from leaves, stems and trunks. It was found in Pennsylvania in 2014 and has since expanded its geographical distribution. The damage caused by the pest, its sugary excrement and sooty mold has been devastating for the Pennsylvania wine industry – reportedly causing a 90% grape loss.
A European biological control agent may help control an exotic pest of apple trees in western Canada. Damage from the apple leaf-curling midge in eastern Canada was effectively reduced by introducing a European natural enemy, Platygaster demades, in the 1990s. The pest arrived in British Columbia more recently, where releases of P. demades are now being considered. First, however, the identity of P. demades needs to be confirmed with molecular tools and its host range defined.
European hawkweeds are invasive in North American pastures, where mechanical methods of control are difficult and ineffective. Chemical control with broad-spectrum herbicides is not selective and relatively expensive, with the weed often recolonising untreated pastures. Insects that feed on hawkweeds in Europe have been studied as potential biological control agents for North America since 2000. Two agents have been released in Canada – the gall wasp Aulacidea subterminalis in 2011 and the hoverfly Cheilosia urbana in 2017.