Start stocking up on bug spray now, this summer will be a doozy when it comes to mosquitoes. After two years of drought and below average mosquito numbers, this year’s wet conditions will see mosquitoes return to regular levels.
Alex Carlson is the public affairs manager at the Metropolitan Mosquito Control District (MMCD). According to him, the drought had a strong impact on the mosquito population over the past few years. “All the ponds and the wetlands had really dried down, and the water levels were really low. And so even when we would get rain, there usually wouldn’t be enough to trigger a major mosquito hatch,” Carlson says.
But after the third snowiest winter in Minnesota history, the state is recovering from drought, meaning that the mosquitoes will be back. According to Carlson, an increase in standing water leads to an increase in mosquitoes. Add in a rainier spring than normal, and the perfect conditions are set for mosquitoes to multiply.
“The most common species we have is the floodwater mosquito. So they lay their eggs on the edges of the pond or wetland, and then they wait for the rain to come for them to hatch,” Carlson says. “And just because we haven’t had that rain they haven’t hatched but those eggs can survive unhatched for up to seven years,” he added.
So, many mosquito eggs have been dormantly waiting for a snowy winter or a rainy spring, and this one is shaping up for optimal hatch conditions. “All the eggs that have been hibernating and waiting are more likely to hatch this year, when we get rain than they were in the previous two years,” Carlson said.
But as a mosquito-riddled state, there are many different species that rely on different hatching methods. Last year, even though there were fewer floodwater mosquitoes, there were actually more Culex mosquitoes, a disease-vector mosquito that relies on standing water to lay eggs.
“So last year, we saw fewer overall mosquitoes, but just as many if not more of the disease vectors,” Carlson says, which meant proportionally high cases of West Nile virus and other mosquito borne illnesses, despite there being fewer mosquitoes overall.
Even though there will be more mosquitoes out this year, there are ways to mitigate them, says Carlson. “The biggest thing that individuals can do is look for their yard and neighborhood and remove any stagnant water that they can remove,” he says. They can lay eggs in pools of water in leftover tires, bird baths, clogged gutters, really anywhere that still water sits for long periods of time. It might be a good idea to check the backyard for any debris that could be home to mosquito eggs.
On a larger scale, the MMCD sprays a biological larvicide to kill mosquito larvae. However, the organization only operates in seven counties: Hennepin, Ramsey, Anoka, Washington, Dakota, Scott and Carver. Although that covers 189 cities, not all of Minnesota is getting aid from a mosquito control agency. The biological larvicide they use, BTI, is available at many hardware stores. Plus, the product is biologically tailored towards mosquitoes so it doesn’t have negative effects for other animals.
For a short term fix, Carlson recommends the obvious—bug spray. For those concerned about DEET, myths about it being harmful have been widely debunked. “I think there was an urban legend in the ’90s that it was cancer causing or something, but it’s been widely tested since then. It’s safe for kids two months old and above,” Carlson says. But for a more natural and less abrasive fix, he recommends looking for lemon eucalyptus oil.
Mosquitoes tend to stay on Minnesotans’ minds—we have a reputation for them, and we’ve learned to live with them. Carlson notes that Minnesota has some of the most nuisance mosquitoes in the U.S.
As we gear up for a mosquito-filled summer with bug spray and BTI, future summers present increased challenges when it comes to the pesky insect. Climate change, while making things worse for every other species, will actually provide ideal conditions for mosquitoes. Warmer, humid summers and less intense winters will allow more mosquitoes to thrive.