Periodic cicadas are not good news for orchardists. The critters prefer to lay their eggs on apple and pear trees, will settle for peach, but also like grapevines and berry crops.

They don’t cause feeding damage. Cicadas feed only by sucking, both as nymphs and as adults. The harm they do cause comes from slits females make in pencil-sized branches where they then lay their eggs – about 500 hundred of them.

Planning for the invasion by postponing planting new trees, netting trees and use of some pesticides (although that has its drawbacks) are the only lines of defense against the insects, according to experts from the University of Tennessee, The Ohio State University and a seventh-generation orchardist.

“They are especially damaging to young trees,” said David Lockwood, a UT extension specialist who works with fruit and nut tree growers. “The older trees, it’s not as bad, but on a young tree, the damage periodic cicadas do to those young limbs can result in either a weak limb, or you may have to start retraining the tree.”

Those periodic cicadas are already out of the ground in some places and still appearing in others. They emerge as a nymph, said Celeste Welty, OSU extension entomologist and associate professor of entomology.

They crawl up a tree trunk where they make that final molt into the adult, leaving their empty shells behind, Welty said. Then the racket begins. The males and females have to find each other, with the males making the commotion, and then they mate and lay eggs.

Singing by the males begins about five days after they have molted, Welty explained. The female begins to lay eggs about 10 days after the nymphs molt to adults and continues for about four weeks.

Females prefer to lay their eggs in young trees with tender bark, Lockwood said. The damage they cause on mature trees, vines or bushes may result in death or breakage of the shoot tips which, while unsightly, won’t cause much harm.

On Scott Downing’s New Madison, Ohio, farm, which has been in his family since 1838, they can still see scars on the limbs from 17 years ago. He remembered having cicada shells 3-4 inches deep under the trees.

“They slit the limb and it’s like a razor blade, said Downing, who runs the farm with his wife Rachelle, and daughters Maddie, Allie and Meghan. “Those cicadas will lay 500 to 600 eggs in that slit. It’s usually about a 2-inch long slit. They like to do it on the small tender growth, which is about the size of a pencil, usually toward the end of the limb. The tip usually breaks off.”

They tend to lay their eggs on the underside of the twig, and have very distinct slits, Welty said. “If you’re only looking at the top of a twig you might not notice them but underneath there are all these eggs. As the summer goes on, the cicadas have died off, you see is all these branch tips start to droop, turn brown, and die.”

A few products are registered for cicada control on fruit crops, Welty said. Pyrethroids such as Asana (esfenvalerate), Danitol (fenpropathrin) and Sevin (carbaryl). For organic growers, Surround (kaolin) is labeled.

But pyrethroids are broad-spectrum, Welty said. They kill the good bugs as well as the bad bugs. Orchardists who do a good job of pest management try not to use them for that reason. What tends to happen is that at the end of this year or next, they get flare-ups of three different pests: San Jose scale, wooly apple aphids and European red mites.

Downing is going to pass on the pesticides. “There are pesticides you can use but really for the damage they do it’s not worth the headache. You have to apply the pesticides to the ground when they’re emerging.

“The worst thing about cicadas is that they love fruit trees,” he said. “They’ll break the ends of all the limbs off – that’s your new growth, which is your apple growth for next year. It will probably do a little more damage to next year’s crop than this year’s. If they make that slit to lay their eggs in anything that is over, maybe three-quarters of an inch in diameter, that’s going to break off and it will be fine. It’s not really harmful. They’re a nuisance and there is not a whole lot you can do about it.”

Downing did talk himself out of planting a new block of apple trees this year. All of the new growth on those young trees would be ruined.

Depending on the number of trees you have, you can physically protect them with netting, Lockwood said. For a small number of trees, small-mesh netting would be the best way because there will be zero damage if the netting is put on correctly.

Five or six weeks after the noise is over those eggs will hatch, Welty said. Gazillions of tiny things, looking like a grain of dried rice, will start tunneling out from the bottom of a branch. They drop to the ground and burrow in about 6-18 inches deep. Later in their life cycle, they go deeper, up to 8 feet down. For 17 years they sup on tree and other roots and grow. Scientists do not consider this to be harmful.