Managing Minute Pests to Mitigate Massive Destruction
Insect infestations in Canadian forests have become a topic of urgent concern spanning all levels of government, from local tree-planting initiatives to federal agency frameworks seeking to identify and control the spread of invasive species. At the top of the list are the Asian long-horned beetle and the emerald ash borer – two species which have devastated tree populations in Canada and the US. Both pests are non-native and invasive; they originate in Asia and after (accidental) importation to Canada, have wrought havoc on forests and killed millions of trees. While the ash borer predictably attacks a variety of ash trees, the Asian long-horned beetle prefers maple. Both species have been consistently present in Canada since the 2000s and have led to significant economic losses and environmental concerns.
Controlling the spread of these pests requires an understanding of their population dynamics. Since multiple varieties came from countries across the vast Asian continent, a proportion of these insects were not equipped to withstand Canadian winters and were therefore of lesser concern to forest pest managers. The first emerald ash borer populations in Canada were found in Southern Ontario and, at the time, were thought to be at the northern boundary of their range. However, within a decade, populations were found in Winnipeg, suggesting either rapid adaptation or incredible plasticity of certain populations in response to the cold Canadian climate. The diversity between these populations in their cold tolerance means that while not all varieties are of major concern for forest protection, some can expand their range and target trees much farther north in Canada than was originally anticipated. This means that the scope of vulnerable regions is unknown and may continue to expand.
Brent Sinclair and his research group from the Department of Biology at Western University are developing genomic tools to address the threats presented by these forest pest species.
These cold-hardy populations are of greatest concern to Canada’s forests and being able to identify them is essential to developing successful management techniques. Developing genomic markers for the species allows the Sinclair group to determine their provenance in Asia – populations from colder parts of the continent are more likely to survive well in Canada. These genetic tools will also be applied to other pest species, both current and in the future.
Forest pests are expensive to manage – the last Asian long-horned beetle infestation in Toronto cost $30 million to control; North America has spent a collective $500 million in total on the pest, which first appeared in Canada in 2003. The high cost of pest management techniques, not to mention the aggressive tactics of cutting down vulnerable trees, necessitate innovation in our fight to stay ahead of these forest pests. Adding genomic tools to the arsenal represents a major step forward in reducing costs of pest management while maximizing the efficiency of population culling.