City taking targeted approach to fight Dutch elm disease
With two new cases of Dutch elm disease confirmed in Regina, both located on the south side, crews are beginning to immunize trees to provide protection from the deadly disease.
The first case, found earlier in July, was located in the north end of Regina.
“We have changed our strategy for how to fight back on it,” said Russell Eirich, manager of forestry, pest control and horticulture. “We have changed our control strategy for the past two years and it was done in a way to lessen our impact on the environment.”
Through trial runs over the past two years, the city began using Eertavas, a product that is injected directly into the tree, rather than spraying to kill elm beetle populations in an area.
“If you think of how cancer treatments used to be, they would irradiate and give large doses of cancer fighting treatments to people,” Eirich said. “Medicine is now more targeted on certain cancers. That is the same philosophy with what we have done here.”
If a tree is found to be infected with Dutch elm disease, neighbouring trees around it will be treated with the product. With large root systems, it is possible for the roots of an infected tree to touch the roots of another tree underground, thereby infecting it as well.
“We are trying to create a wall between healthy trees and diseased trees,” Eirich said. “This helps keep the disease from moving.”
To treat the trees, city crews drill directly into the tree’s root layers and push the product in. Over the course of a day, the tree sucks the product in, helping to immunize it. The process costs $200 per tree, and the city will do an average of 100 trees a year. The average cost is $20,000 per year, compared to $40,000 to $45,000 to use the spray program.
On the mosquito side of things, the city is having a banner year when it comes to the annoying blood-suckers. An average of only 15 mosquitoes have been found per trap, well below the historic average of 68 mosquito per trap.
“This is one of our better years for mosquitoes,” Eirich said, adding that things can still change over the next two months. “It depends on the weather and what it throws at us. We are in a drought, there is going to be a lot of ability of the ground to absorb water. If we do get that rain, then heat, then rain and heat, that will push our numbers.”