If You See This in Your Yard, Insects Are About to Invade, Expert Warns

Look for the holes cicadas can produce in your lawn.

The Brood X cicadas live underground for the 17 years they lie in wait, but eventually they have to bust through the ground to make their great escape, which could result in holes in your yard. "We’re seeing holes—holes all over the place. Those are holes made by the cicadas," cicada expert Gene Kritsky, PhD, dean of Behavioral and Natural Sciences at Mount St. Joseph University, told NBC affiliate WLWT5. Kritsky said the finger-sized holes are up to an inch long and can easily disappear after rain. CNN noted that these holes are commonly found at the base of trees. And for more on nearby pests, If You See This Bug in Your Home, Don't Step on It, Experts Warn.

And see if you spot any mud chimneys.

According to the University of Maryland, some nymph cicadas construct mud chimneys over the emergence hole. These mounds of mud may be two to three inches high and one to two inches wide, with a hole that's about half an inch wide in the center. Cicada Mania notes that cicadas tend to build these chimneys in wetter, muddier areas—otherwise, they simply make the holes. The chimneys help keep water and mud from sliding into the holes, so the cicadas can continue to breathe, pop up to check the surroundings, and prepare to emerge.

Kritsky said he's received at least half a dozen reports over the past few days that people are seeing mud chimneys in the Cincinnati area. "Those were made during the rain we had last week. During a nice constant rain, some cicadas will actually extend their tunnel above ground," he explained. And for more signs that insects are on the horizon, If You See This in Your Yard, Prepare for a Bug Invasion, USDA Says.

You might also come across cicadas when gardening.

If you're heading outside to start prepping your yard for summer, keep an eye out for cicadas lingering just below the surface. Kritsky said he recently received reports from people who dug up cicadas while gardening or doing other yard work. "If you went out and dug up cicadas today, what you would find is that the nymphs have red eyes—which means they’re coming out this year—but they have not yet developed these characteristic black pouches behind their head," Kritsky said. "They’re not ready to emerge just yet." And for more useful information delivered straight to your inbox, sign up for our daily newsletter.

Expect the Brood X cicadas to emerge in mid-May.

Jessica Ware, PhD, an associate curator of invertebrate zoology at the American Museum of Natural History, told Reuters she expects the Brood X emergence will be sometime around May 13. Kritsky agreed that the cicadas would likely emerge during the first half of May, but noted that they'll likely peak in late May and June. "We had a lot of people very excited last week when we hit the 80s, thinking, ‘Maybe they’ll come out a month earlier.’ But they’re physiologically not ready to emerge," he said.

A warm rain will likely trigger their emergence. These cicadas' lifespan is about four to six weeks above ground before they begin to die off. However, since they don't all emerge at once, you shouldn't expect them to all be gone within six weeks—there will be some lingering late bloomers. And for more signs of infestation, If You Smell This in Your Bedroom, You Might Have Bed Bugs.