By Rhonda Massad
Since it’s first detection in Canada in 2002 the emerald ash borer (EAB) has caused countless deaths to ash trees across North America. It’s larve bore labyrinths of tunnels under the bark and disturb the flow of sap in the tree that dies quickly once infected.
In addition to the threat on forest biodiversity and the impact on heat islands, loss of ash trees will have a significant impact on municipalities and the hardwood industry. The challenge facing municipalities is how to control the shiny green insect that originated in Asia where it has no natural predators in North America.
The city of Montreal began testing a new biological control agent to manage the crisis this summer. Several traps have been set up where the EAB can find it’s way out but not before being covered with a fungus that would proceed to infect other EABs that it comes in contact with.
As hoped by Canadian Forest Services Pierre Desrochers, at in an EAB management seminar earlier this year, the method of auto contamination by the spread of a fungus to the EAB will become prominent shortly. When the EAB enters a Lindgren trap designed to attract the EAB, the bug then becomes infected with fungus spores that it carries back to other adult EAB in hopes of reducing the active adults and egg laying females.
According to a recent report by Professor Claude Guertin of INRS-Institute Armand Frappier, this is the first study that compares the microbiome of males and females of the EAB and those of different populations of Quebec and Ontario in hopes that the data collected will help to better understand the life cycle and favorable conditions for the spread of the emerald ash borer. This strategy avoids blanket spraying of the selected fungi which may affect other insects, but rather provides targeted control of EAB.
A variety of approaches may need to be integrated to successfully manage the EAB population. Further testing will be required before biocontrol products can be produced on a larger scale or be approved beyond research trials.
To date, Tree Azin, a class four bio pesticide, derived from the Neem tree, that is injected into the bark of the tree has been the preferred choice in Canada. The product, produced by BioForest Technologies, is relatively new as is the ash crisis. The treatment must take place every two years for the life of the tree.
“Tree Azin has risks as do all pesticides. We want manage the mortality of the ash trees and it is our hope that we are not treating with Tree Azin in ten years from now,” Laval’s Green space division Forestry engineer Daniel Boyer stated in the same seminar, “our intention is to gradually replace the trees with a variety of species to avoid any future incidents like this.”
According to Boyer there is a residue of Tree Azin remaining in the leaves that fall to the ground. Tree Azin should not be injected in ash trees that line bodies of water as it will impact the eco systems within the water and on the shore line.