Cicada swarm to emerge this month across Western Pennsylvania

Rising temperatures are heralding the return of the 17-year cicadas.

The insects have been waiting underground for nearly two decades, but are expected to emerge by the millions this month.

It takes several days of sustained warm weather, with temperatures consistently above 60 degrees, for cicadas to come out of the ground, said Sandy Feather, horticulture educator with Penn State Extension in Allegheny County.

“You’re not going to have much insect activity below that,” she said. “It’s not until the soil warms up that they’re going to hatch out.”

This year’s cicadas are part of Brood VIII, which is concentrated largely in South­western Pennsylvania. There are other broods, some of which include Pennsylvania as part of their territory, but Brood VIII is concentrated almost entirely in this region.

There will be lots of cicadas and they will be loud, but Feather reminds residents that they do not pose a threat.

Adult cicadas do not eat or bite. They will not harm crops. They exist only to mate, and they’ll all be dead by the end of June.

“I just try to get people to calm down about it,” Feather said. “I realize that big bugs with bulging red eyes scare people.”

She’s looking forward to seeing the cicadas’ entertaining antics, she said.

“They’re horrible, clumsy fliers. I can almost fly as well as they can,” she said.

The one risk they do pose is to very young trees.

Female cicadas lay hundreds of eggs in live twigs. In adult trees, this can kill small branches but doesn’t cause lasting damage.

In young trees, it can cause permanent harm. Feather encourages owners of young trees to wrap them in garden fabric to prevent cicadas from getting to them.

She works with the Penn Hills Shade Tree Commission, which has postponed its usual spring tree planting until after the cicadas are gone. Others thinking about planting trees this year might want to do the same.

“They’re going to be gone for 17 years, and then in 17 years the trees will have grown enough to be able to withstand the damage,” she said.