The Emerald Ash Borer has finally made its way to Brome County where it will start to kill our Ash trees. White Ash is an important companion species to the maple-dominated hillside forests of our region. The species is especially abundant in the eastern half of the Brome-Missisquoi MRC (TBL, West Bolton, Bromont, Sutton and Frelighsburg).
The Emerald Ash Borer (known to its enemies as EAB) originated in China, Korea and Japan, where the Ash trees have developed considerable resistance to the insect through natural evolution.
The insect was first discovered in Michigan and Southern Ontario in 2002 and has since spread to all of the eastern States, to the rest of Ontario, Quebec, New Brunswick, and in 2018 to Nova Scotia. It attacks the White, Green and Black Ash found in our forests.
The beetle is bright green and lays 60-100 eggs under the bark in the upper branches. The eggs hatch and the larvae feed on the cambium and inner bark of the trees, girdling it and preventing the passage of water from the roots to the foliage. Trees out in the open are attacked first. It will take many years for the EAB to find all the Ash in our forests.
The first signs of trouble are yellow leaves during the growing season. It usually takes two years for the tree to die. It is possible to inject an insecticide to kill the larvae, but it must be done every year and costs between $200-300 for each treatment.
You might treat the tree on your front lawn, but it is not possible to treat all the Ash trees in the forests around us. Approximately 10-15% of the trees in our forests are White Ash, less common Green Ash and Black Ash found in wetlands.
Ash trees produce lots of seeds each year. They germinate and grow into saplings. With luck, over time our three species of Ash will develop resistance to the EAB. Get to work Darwin!