Andermatt Canada success story with Lymantria dispar MNPV

Andermatt Canada was established in 2006 and has been helping Canadian and American forestry managers regulate Lymantria dispar populations since 2009. Lymantria dispar is an important forestry pest with an exceptionally broad geographical range, from its native territory in Europe to Northern North America. Recently, Andermatt Canada helped to limit the Lymantria dispar outbreak in the city of Toronto while aiding the city to overcome public concerns with species at risk within the application area. 

Lymantria dispar feed on deciduous trees across the Canadian landscape. Lymantria dispar were accidently introduced to North America in 1869, in Massachusetts, USA. It subsequently spread into other parts of the U.S. and into eastern Canada, with reproducing populations now established in Ontario, Quebec, New Brunswick and Nova Scotia. If left untreated, Lymantria dispar defoliation causes significant growth loss and weakens the tree’s resistance to other insects, diseases, or other stressors – particularly drought. The difficulty in controlling this species with current control measures is highlighted when species at risk inhabit the same environment. In the fall of 2021, an Emergency Use Registration for BoVir was submitted for use in the province of Ontario, Canada. BoVir is a new control tool based upon the Lymantria dispar nucleopolyhedrovirus. BoVir is a great tool to utilize in areas where species at risk are present, as the host range for baculoviruses is limited to its host species, Lymantria dispar

In 2021, Lymantria dispar were responsible for defoliating 586,385 ha of forests in urban and rural areas of Ontario. High Park, located within the City of Toronto, Ontario, is a valuable space which is home to important oak species, but also provides an important tourist destination and urban park within one of Canada’s largest cities. As a remnant forest with a unique ecosystem, High Park also provides habitat for other uncommon, rare, threatened, or endangered species, including Lepidoptera. This mix of Lepidoptera includes six species of butterflies, and 15 species of moths, many of which have a high-level conservation status. It also includes the possible presence of the endangered mottled dusky wing (Erynnis martialis). This niche site is where the application of Bovir fit perfectly to reduce Lymantria dispar populations to protect tree health and lower the possibility of a Lymantria dispar outbreak, while also having no impact on non-target Lepidoptera that may inhabit the same ecosystem.

The Lymantria dispar infestation was particularly severe in High Park during the summer of 2021 and most oak trees in the park were completely (100%) defoliated by the caterpillars. In the spring and summer of 2022, after treatment with BoVir, the tree canopy flourished all season. The park was able to return to providing habitat for species at risk. BoVir was one of the integrated pest management tools used by the City of Toronto to protect trees in High Park during a prolonged Lymantria dispar outbreak. 

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