Gnats or not, why the bugs are biting — and what to do about it

It’s not gnats making you nuts.

At least, that’s what urban entomologist Amanda Bachmann suspects, based on the descriptions she has been getting from East River residents bedeviled by flying pests.

These insects are smaller than houseflies but definitely visible, Bachmann said. Without having a picture to examine, her best guess is that the insects are black flies.

“I’ve gotten a fair number of questions and calls and reports from the eastern side of the state,” said Bachmann, who works for the South Dakota State University Extension Service. “’Gnats’ is a very broad term for flying insects. I think the insects that people are encountering are the black flies, which are active for three or four weeks in late spring or early summer.”

Denise Patton, a health program coordinator with the city of Sioux Falls Vector Control Program, also has received her share of queries about the gnats that have been dive-bombing city residents and inflicting bites that can leave painful welts.

“This time of year, when obviously all insects are super happy, the weather’s nice enough, the water warm enough, the habitat is lush enough that they multiply and breed,” she said. “It seems like we go from blizzards and shoveling to ‘oh my gosh, a ton of insects.”

Gnats, a.k.a. black flies, breed in flowing water, as opposed to mosquitoes that prefer stagnant water. They also come out in swarms, Patton said, making their presence known quickly as opposed to the stealthy mosquito.

Black flies also can travel 5 to 10 miles from their spawning sites, Bachmann said. Calm days make them peskier; windy days keep them away.

If there are more black flies than usual, that’s a good sign for the region’s water quality, Bachmann said. Streams and rivers are flowing strongly. With Lincoln County’s higher water table, residents sometimes see a higher mosquito population, Patton said. In areas like central Sioux Falls, with fewer parks and greenery and more concrete, insects might not be as prevalent.

“Gnats need to stay cool in the day,” she said. “They hang out in longer grass like a lot of insects do. They get kicked up and agitated easier.”

The good news is that basic biology means they will subside shortly as their time in the sun, so to speak, ends, she said. The city of Sioux Falls also has begun its mosquito spraying program, which also likely will knock down some of the gnats, Patton said.

More good news: While the bites may be painful to some of their victims, they don’t spread disease like mosquitos and ticks can.

“We don’t need to worry about any diseases; it’s just a pain,” Patton said. “I do hear more often than not that gnat bites tend to swell up more than mosquito. Some people are super sensitive. It’s super individual as a whole. My experience is that gnat bites tend to be a lot worse.”

A little bad news: There’s not much that can be done to repel the gnats. They’re attracted to dark clothes, so wearing light-colored clothes with long sleeves and long pants may be effective to a certain point, Bachmann said.

“DEET can repel; however, some do not respect insect repellent,” she said of the black flies. “If you’re on a patio, fans work on mosquitoes. But black flies are a bit of a stronger flier, and on calm nights they can be really vicious.”

DEET is the active ingredient in most insect repellents. They repel the insects, not kill them.

Some natural repellents like vanilla, eucalyptus and cedar and manufactured products like Avon’s Skin So Soft has been tested and found to work against insects, Patton said. However, they do not last as long and must be reapplied frequently.

The most important thing a person can do is to use an EPA-registered repellent, Bachmann said. Some botanically derived options do have EPA approval. A product without that strength will not provide the protection needed. And while Bachmann has been told that “vanilla trees” — those scented cardboard cutouts designed to freshen car interiors — are sold out in Brookings, hanging one of those from your hat likely will not be effective.

“Don’t just use something in the kitchen,” she said. “You’ll just smell like a fancy candle.”

Using the proper insect repellent will protect people from the more dangerous insects like mosquitoes and ticks longer after the black flies have subsided for another season, Bachmann said.

You also might want to take time now to clean out places that serve as mosquito-hatching habitats, such as gutters, birdbaths, water features and kiddie pools, Bachmann said.

“There are lots of places, human-made places, that mosquitoes can breed,” she said.

As for how to handle it when they do bite, Lewis Drug clinical pharmacist Courtney Feist recommends cleaning the area with soap and water.

Then, use a cold, wet cloth on ice on the bite or sting for 10 to 20 minutes to help with pain and swelling.

“Something such as 1 percent hydrocortisone cream can be placed on the affected area or areas several times a day to help with symptoms and itching,” she said. “Some patients may benefit from an oral antihistamine — Zyrtec/cetirizine, Allegra/fexofenadine or Claritin/loratadine — to help with itching. Typically, the topical antihistamine creams do not offer much relief. Pain relievers could also be taken depending on if there is pain.”