Drones, helicopters, climate change: The world of mosquito-fighting

The annual battle against the blood-sucking pest is yet another thing at the mercy of climate change

A new mosquito-fighting gadget could help control the pesky insects in the Fraser Valley next year.

The company contracted by the Fraser Valley and Metro Vancouver regional districts to manage the mosquito population hopes to start using drones to better control the pests.

The potential tech solution comes after 2022's particularly horrible mosquito year.

Expectations vs Reality

The speed at which the snowpack melts each year plays a big part in Morrow BioScience’s ability to manage the mosquito population. The uncertainty that comes with each season makes executing a treatment plan challenging, the company’s lead biologist, Dirk Lewis, told The Current.

Climate change has accelerated how quickly the water is released from higher elevations—the higher the freshet, the greater the flood area that needs to be treated.

This year’s snowmelt, like the year before, didn’t follow the trend.

“We saw another strange year with the snowmelt—most of the snow came out quickly and early,” Dirk said.

The Fraser River peaked in late May at just over 5.5m at Mission, which Lewis said is a relatively high and very early peak. Last year, the peak was even higher, but much later: the river hit its high point on July 4 at just over 5.8m.

“The differences are that this year the water came into a relatively cool system and didn’t stay high for very long,” Lewis said. “Last year the water came into a warm system and stayed high for quite a while.”

Treatment is simpler in cooler weather. It allows for a longer treatment window in a shorter freshet.

The treatment plan is much the same for the valley’s hotspots: Fort Langley, Fairfield Island, Island 22, the southside of Mission, and the area near the Hope golf course.

Last year, Morrow surpassed its FVRD mosquito-fighting budget by $300,000, spending $436,500. Lewis couldn’t confirm how much was spent this year, but said the treatment was less than one-third of what was required in the FVRD last year. This year, Morrow treated about 135 hectares in Langley and 975 hectares in the FVRD.

“Overall the adult mosquito population is considerably less than last year,” Lewis said.

Only time will tell how future freshets will impact the insect population.

Plan of attack

Winning the annual war against mosquitoes requires understanding the spring freshet. The company maps every floodwater area it treats.

When the water rises during the spring freshet, mosquito eggs laid last year in the soil hatch. Those males and females will mate. Later the females fly off in search of a blood meal. “Those are the ones that are bugging us,” Lewis said during a presentation to Fort Langley residents earlier this year.

Once the freshet recedes, the female mosquitoes return to lay their eggs in that soil and in a matter of months reach the end of their lifecycle. Those future blood-sucking predators will be on Morrow’s watch list the following year.

The target is the larvae. There is no treatment that will effectively kill adult mosquitoes without harming the environment, Lewis said. Morrow uses a larvicide created with a bacteria found in corn that the company says is harmless to non-mosquitoes.

Ground crews will “treat all the areas as the water is coming up to kill those mosquitoes to kind of hold them off until the water is high enough that we can do the whole thing with a helicopter,” Lewis said.

But that strategy has its limits. The helicopter is sometimes reassigned to more pressing issues like fighting forest fires. Morrow is at the mercy of climate change.

“This year the forest fires didn’t wait until the flood season was over so we have no helicopter,” Lewis said.

When a helicopter is no longer in Morrow’s arsenal, the plan of attack shifts to focus on ground crews.

But Morrow could have a new weapon to draw on next year: drones.

“There are a number of sites with relatively low canopy (an absence of cottonwood trees) where we feel the drone will be effective,” Lewis told The Current.

The use of the small aircraft is still in the permitting phase, but Lewis is optimistic they’ll be ready to deploy next year.

“Permitting restrictions will ultimately dictate where we can and can’t use them,” he said.

But Lewis doesn’t expect the drone to improve the regional districts’ bottom line.

“It will allow for some increase in flexibility with respect to timing—a helicopter costs a lot more to mobilize, so the drone may help with that,” he said.

“The vast majority of treatments, at least in the near term, will still be with the helicopters.”

In the meantime, if the blood-sucking insect is being a pest Lewis’ advice is to wear light-coloured, loose-fitting long sleeve clothing. Mosquito repellent can be used as an added layer of protection.

“Remember to look around your property for pockets of standing water.

“The mosquitoes are quite active now and if you're bothered on the patio it's likely that there's something producing mosquitoes close to where you like to relax.”

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- Tyler, Joti, and Grace.

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