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.