By Brett McKay
You've probably never swatted a mosquito and stopped to ask yourself if it was a Culex or an Ochlerotatus, but that is one of the considerations guiding Edmonton's ever evolving pest control program.
There are dozens of mosquito species in the region, hatching in waves over the course of the summer. Some, like the complex of species that develop in cold-water environments in early spring, are often naturally limited to one generation a year. Others, like the Culex subspecies, are the most common carriers of the West Nile virus, though that is fortunately less of an issue this far north.
The most bloodthirsty and populous varieties that breed in the warm months and ruin your summer outings are the main concern of the city's pest department.
"When we start seeing Ochlerotatus dorsalis and Ochlerotatus spencerii, those are spring developers, and they're also quite aggressive daytime biters," said the city's pest management coordinator, Mike Jenkins. "When they show up, that gives us a warning that those species are developing. And so, we can target our programs to look for the larval development, and to concentrate our efforts on the sort of sites where those species are developing."
The pest control teams gather weekly data from sources such as light traps placed around the city, weather forecasts, and observations of larvae growing in standing water. From that, they make projections and determine their response, meaning their approach is constantly being adjusted. For the past few years, the city has also been incorporating carbon dioxide bait traps that mimic human scents to supplement the data gleaned from the light traps.
"They're more effective. They draw in all the species that we're looking for, not just the ones that get attracted to the light," Jenkins said. Unlike light traps, the BG-Sentinel carbon dioxide traps can also be used during the day, when some of the most aggressive biting species are active.