Swarms of Stink Bugs Invade Southern Utah: 'Never Seen Anything Like This'

Swarms of bugs have infested parts of southern Utah, with residents in the city of St. George reporting large numbers of green stink bugs in particular, as well as gnats, false chinch bugs and other insects.

The latest events come soon after vast swarms of grasshoppers and "Mormon crickets" descended on Las Vegas and southern Idaho, respectively.

Like in Idaho and Nevada, experts say that the sudden appearance of vast insect swarms in Utah is largely down to environmental factors, such as the wet conditions that many areas have experienced so far this year.

"We've got a couple of things going on. One is the really wet winter and spring that we had," Bill Heyborne, an entomologist from Southern Utah University, told St. George News. "And then, we had kind of a slow summer warm-up, and so a lot of things just stayed dormant, eggs underground, that kind of thing, and then it warmed up really quickly. I think the combination of the two has led to a lot of the outbreaks that we're seeing."

"Insects are so tied to environmental conditions, temperature, moisture, food availability, all of those things," Heyborne said. "Sometimes, the stars just align and conditions end up being just perfect for a particular species of insect. And so you'll get a very large outbreak one year and then you won't see them for a decade. There may be a few here and there, but nothing much. And then the stars will align again you'll see them again."

One St. George resident, Chad Hanvey, recorded video footage of thousands of insects swarming around his car while he was pulling up at a gas station.

"I didn't smell them, but I didn't roll down my window to see if they stink. I didn't want to find out," he told Fox 13. "I'm not scared of them, there were just too many. They were all over my truck, and I figured they'd be all over me."

"I've lived here five years. Never seen anything like this," he said. "Everyone calls it a seven-year hatch, but I haven't seen that many bugs in 43 years."

Kristopher Watson, an entomologist at the Utah State Department of Agriculture and Food, said the video shows large numbers of other insects besides the stink bugs, including gnats and mosquitoes.

Experts predict that the infestations will likely fade away within a few weeks, but until then, there is not much that can be done, other than turning off lights at night—which attract insects to homes—and making sure windows and doors are sealed.

"If insects are in people's homes and causing problems, they really ought to call a professional exterminator and deal with that," Heyborne said. "Outdoors, there's not a whole lot we can do. I mean, people could use insecticides, but often insecticides come with their own risks and their own side effects. So my recommendation for people is if they're outside, no, I'm sorry. You're going to have to just deal with it."

The invasion of insects in Utah follows similar events in southern Idaho and Las Vegas—where a swarm of grasshoppers descending on the city was so big that it showed up on weather radar.

green stink bug
A green stink bug (Nezara Viridula) on October 03, 2016. OMAR TORRES/AFP/Getty Images
Swarms of Stink Bugs Invade Southern Utah: 'Never Seen Anything Like This' | U.S.