Fox News Weather Center

17-Year Cicadas Set to Re-Emerge

As summer creeps nearer, 17-year cicadas are preparing to re-emerge from the Carolinas and head northward.

Washington, D.C., Philadelphia and New York City will likely see the pests by early June.

Cicadas rise from underground when the soil temperature reaches about 64 degrees at a depth of at least 8 inches.

"Thermal soil temperature is one of the things that trigger their emergence, along with a gentle to moderate rainfall," Greg Hoover, Senior Extension Associate Ornamental Entomologist at The Pennsylvania State University, said.

The bugs are not a threat to humans, but can be damaging to trees.

Placing garden netting over small trees will prevent the cicadas from laying eggs in branches. Foil wrapped around tree trunks can also keep the cicadas from climbing up the tree.

"Once the cicadas emerge, they only have a lifespan of two to three weeks," Mozgai said. Lives of cicadas can be shortened by the effects of wind and rain on their bodies. Those whose bodies are deformed by the weather won't live as long as the ones who develop normally, he said.