City crews step up monitoring for Dutch elm disease

The oldest tree in Regina has been around for every Grey Cup championship, survived the Regina Cyclone, and has seen the downtown core around it grow and change. The elm tree is located in Victoria Park, dates back 116 years and city crews work hard to protect it from Dutch elm disease.

“It takes a long time to grow a tree like this and there are only two or three this size in the city ... but with Dutch elm disease, it can take a tree like this out in a manner of weeks,” said Russell Eirich, manager of forestry, pest control and horticulture. “That is why (fighting) Dutch elm disease is so important.”

Dutch elm disease first appeared in Regina in 1981, killing one tree. For the next 11 years, no trees were lost but from 1992 to 2016, 93 trees have been killed by the disease, including three last year and 11 in 2015.

To mitigate the loss of trees in Regina, the city has implemented a full-scale surveillance campaign.

“Dutch elm surveillance crews go up and down streets looking for trees with Dutch elm disease,” said Eirich. “We are looking for a whole part of the tree to die all of a sudden. Leaves curl up and die, but they don’t fall. These things will take a hailstorm to knock it off a tree.”

Once a tree has been identified, a small branch will be removed and the bark will be peeled back. If there is staining under the bark, then the branch is sent to a laboratory for testing.

“If it comes back positive, that tree will be removed the next day and we will do things to protect the surrounding trees,” said Eirich.

Residents are asked to monitor trees in their neighbourhood and call Service Regina at 306-7777000 if they see a tree that may be infected with Dutch elm disease.

On the tent caterpillar side of things, the city has wrapped up its campaign after spraying 13,975 trees this spring, well over the 10,000 originally planned and nearly double the 7,000 sprayed last year.

“We were more prepared this year,” Eirich said. “The tent caterpillars caught us last year. We were more aggressive and watchful in predicting where they were going to be.

With last week’s rain, and with more expected Friday, there will be an increase in the number of mosquitoes in the city, but numbers are still well below the historic average. In city traps last week, only eight mosquitoes on average were found. The average is 20 per trap. Last year at this time, there were 59 mosquitoes found per trap.

“We have had a bit of rain lately since June 9 ... that means the water is coming and the mosquitoes will come,” Eirich said. “We are expecting numbers to increase by the middle of next week.”

In an effort to get a jump on the coming mosquito swarm, the city is treating water throughout the city to limit mosquito numbers.