KNOXVILLE, Tenn. (AP) — The periodical cicadas that emerge every 17 years are due to show up again in Tennessee, and University of Tennessee Extension officials say they could threaten young fruit trees.

Trees are at risk if there is a large cicada population nearby, the university Institute of Agriculture said.

“Even a single female cicada may cause a lot of injury,” David Lockwood, a University of Tennessee Extension specialist who works with fruit and nut tree growers, said in a news release.

Some insecticides can be used to prevent damage, but blocking cicadas is more effective, extension entomologist Frank Hale said.

“Covering the canopy of young plants with netting having a mesh size of a quarter inch or less and tying it around the trunk under the lowest limbs will provide a physical barrier to cicada egg laying,” he said.

Lockwood recommends using a frame to suspend the netting so it doesn’t damage small branches.