Twin Cities’ mosquito numbers in July are down so far compared to average, report finds

Despite a rainy spring and early summer that began with a spike in the number of mosquitoes in the Twin Cities, there have been far fewer of the blood-sucking insects in July than usual, according to a new report.

The first week of July is typically when mosquito season peaks in the Twin Cities, according to the Metropolitan Mosquito Control District (MMCD). The organization releases weekly reports showing the average number of mosquitoes found in traps and compares it with the 10-year average.

The most recent report noted that around 250 mosquitoes were found per trap in the first week of July. That’s less than half the average of 600-plus mosquitoes per trap for that period of time.

Scott Larson, an assistant entomologist with the MMCD, said he thinks part of the reason is the drought in the Twin Cities over the past three years. Though there’s been significant rainfall this year, the previous few years have been much drier and affected mosquito populations, he said.

“Both species are highly dependent on rainfall and the last three years of drought have really crashed their populations,” Larson said in the weekly report.

The MMCD reports show that while May had an above-average number of mosquitoes in the Twin Cities, that total hasn’t increased since, unlike the 10-year average.

Clare Shirley, owner of Sawbill Canoe Outfitters in Tofte, Minn., said that while mosquitoes have been prevalent this summer, it’s been “a normal amount of prevalent” and fewer than in the previous two years.

Others said the mosquitoes have been especially bad. Pete Marshall, communications director for the Friends of the Boundary Waters Wilderness, said a group of students recently returned from the Boundary Waters and did not have good luck.

“They had quite the experience with mosquitoes; it has been a buggy year for sure,” he said.

Marshall and Larson said the best ways to avoid mosquito bites are to use bug repellant and wear clothing that’s designed to keep mosquitoes away.

“I always recommend people wear loose-fitting layers of clothing,” Shirley said, noting that all of her staffers have a Bug Shirt, which has long sleeves and a mesh net that covers the face.

Repellant sprays with DEET are effective, but Larson said it’s important to note that applying heavier amounts of DEET does not make it more effective. DEET can be damaging to synthetic clothing, but other sprays such as permethrin are designed to be used on clothes.

Marshall stressed that each person reacts differently to mosquito bites. In Marshall’s case, that means not using any spray.

“I’m kind of used to it, and have the mentality that it’s part of the experience dealing with bugs,” Marshall said. “I’m at the point where I don’t swell [when bit].”

Mornings tend to have fewer mosquitoes than evenings, Marshall said. He suggested that those exploring the outdoors should avoid dark clothing, to which mosquitoes are more attracted.

More weekly updates and information on mosquitoes can be found on the MMCD website at mmcd.org.