Emerald Ash Borer
If you've been fortunate enough to enjoy the beautiful weather in Mount Royal Park in recent weeks, you may have noticed unusual installations in some of the park’s trees. This, in fact, is a new experimental program for biological control of the emerald ash borer.

The emerald ash borer is an insect of Asian origin that attacks all species of ash trees, causing their death within a few years. This is a critical issue in Mount Royal Park as it’s estimated that ash trees account for 25-30% of the mountain’s tree population. At the present time, there is no treatment that eradicates the insect in a territory.

However, GDG Environment, in collaboration with the Laurentian Forestry Center, Natural Resources Canada and the INRS-Institut Armand-Frappier, is currently developing a method to fight the emerald ash borer invasion using a fungus called Beauveria bassiana. This method traps borers in a funnel containing the fungus. These devices are currently installed in various ash trees in the park.

The Beauveria bassiana fungus has been used for more than a decade by greenhouse producers to eliminate certain insects that are harmful to crops. It’s naturally present in the soil, and most people residing in Quebec have already been exposed to this fungus, without consequence. This fungus is safe for humans and animals and is completely harmless to bees, which sometimes carry its spores and help fight against other insects. If effective, this treatment should be done annually.

Other Experimental Projects and Treatments of Ash Trees on Mount Royal

Another project addressing the effects of the emerald ash borer is underway in Westmount’s Summit Woods. It consists in releasing natural enemies of the emerald ash borer (parasitic wasps of the Tetrastichus planipennisi and Oobius agrili species) in wooded areas. Both these parasitoid species hail from China, from the same geographic region as the emerald ash borer. This treatment has been used since 2015 in other locations in Montréal. This project will span several years to monitor parasitoid populations and validate their establishment.

Moreover, insecticide injection work with the TreeAzin biopesticide, the most well-known and commonly used treatment in Montréal, began this week in Mount Royal Park. A few thousand ash trees in wooded areas will be selected for this operation.

Impacts of the Emerald Ash Borer

All efforts to slow infestation are essential. The disappearance of ash trees poses a threat to Mount Royal’s biodiversity as it will lead to gaps in the forest especially in the canopy forming its upper layer. These gaps would provide space for colonizing species, many of which are undesirable, with better access to light, thus allowing them to spread. To counter the damage caused by the disappearance of ash trees and protect the Mount Royal ecosystem, it will be essential to carry out planned plantings and control the spread of invasive exotic plants.

Mount Royal gets a little help from its friends! Les amis de la montagne’s team of biologists is actively documenting the state of health of the mountain’s trees and natural environments and working with institutional owners to develop a common action plan for the preservation of Mount Royal’s forest canopy.
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