River’s dynamics supports mosquitoes

It’s impossible to take a walk outside without being bombarded by mosquitoes in Williston.

The pesky bugs are relentless, buzzing in peoples’ ears and leaving pink, itchy bumps on your skin wherever they bite.

The Williston Area Vector Control District 1 is busy fogging at night and using Rick Marburger’s Aero Spraying Service during the day to spray. A month ago, the United States Air Force completed a mosquito control mission that killed a lot of larvae.

Residents continue to wonder why Williston suffers, however, with the pesky bugs. Many residents feel they aren’t seeing the benefits of what the Air Force, vector control and Aero Spraying have done, only because it’s difficult to see any bright side of the situation when they are attacked by mosquitoes on a daily basis.

No matter what vector control or any other agency does to ward off mosquitoes, the fact is they’ll always be around. It’s because of Williston’s proximity to the Missouri River, and what happens with the river when the weather warms up.

The river bottom is five miles across, much bigger than the Red River to the east, said Fran Bosch, vector control director. It’s a much larger river with a larger flood plain, he said. When the temperatures rise, the river rises from the melting snow pack coming from Montana, and it rises so high it overflows.

When the river overflows, the water spilling over onto land covers mosquito eggs and incubates them until they hatch. Although it’s called the “June Rise” when the Missouri River rises in late spring, it doesn’t happen just once, Bosch said. There are several pulses that send water over the edge of the river.

Another problem that can’t be helped is mosquito eggs hatch at different times and don’t hatch at once, he said. That’s one of the reasons why even though the Air Force mission was deemed successful, many mosquitoes had yet to hatch by early June and the eggs are hatching now.

“For years now, these mosquito eggs don’t all hatch at the same time, and some studies show that they are viable for up to 15 years. So we could still have mosquitoes from the early 90s in there just waiting for the conditions to be right so they hatch,” Bosch said.

“And what we’re doing with this extensive larvaciding down on the riverbottom is cutting back on that supply of eggs that are in the soil, and the more we stop in the water, the more that won’t get in the air,” Bosch added.

The area is in its second major hatch of the year, followed by the second major flooding event that has caused the river to rise a foot more than it did earlier this spring, he said. That equates to hundreds of acres of land that’s freshly inundated with stagnant water, which is a perfect breeding ground for mosquitoes.

When it comes to using chemicals to kill mosquitoes, vector control also has to be cautious when treating certain lands. Public land owned by the North Dakota Game and Fish Department, the Army Corps of Engineers and the Fish and Wildlife Service can’t be fogged because the entities don’t allow it, Bosch said.

Instead, vector control has to use larvacide on that land to keep mosquitoes from turning into adults, but keeps them in the food chain. It doesn’t kill the bugs outright like the VectoBac chemical the Air Force uses, Bosch said.

The mosquito problem won’t lessen by much in a year’s time, and Williston is always going to have mosquitoes. The assistance from the Air Force, which plans to be back next year and possibly later this summer could produce a noticeable difference in a few years. So could the revenue vector control receives from the water bill surcharge people approved last year, which helps it to be able to buy more chemicals.

“This is not a process that’s going to happen just this year...it’s been a cancer that’s been building, we’re giving it initial chemotherapy treatment. In the next two to three years, we should see a drop in trap counts,” Bosch said.