Noisy visitors: Cicadas will soon return to the area

Insects to appear on trees after 17 years underground

By MARY MARGARET PECHT, Sentinel reporter, mmpecht@lewistownsentinel.com
LEWISTOWN — The cicadas are coming, and nothing is going to stop them!

The periodical cicadas — commonly, but mistakenly, called 17-year locusts — are just about ready for their grand, noisy entrance into the eastern half of Pennsylvania once again.

Even now, the nymphs are lying about an inch below the soil’s surface, waiting to emerge from late May through June in the central and eastern portions of the state.

In some affected areas where the ground is damp, observant homeowners already may have noticed that periodical cicada nymphs have built small, earthen turrets over their holes to protect their escape routes from too much moisture, said Gregory Hoover, an extension entomologist from the Pennsylvania State University.

The mature nymphs of Brood XIV will emerge from their 17-year cycle of feeding on tree roots and crawl a few inches to a foot up a vertical surface — anything from a tree, a small plant, a post, the side of a building, and even a strong blade of grass. There, the nymphal skin will split, the wings will pop out, the soft exoskeleton hardens and darkens, and the sexually mature cicadas will fly off too mate.

During some years, practically all the population of a brood from a forest may emerge in a single night.

Residents of Mifflin, Perry, Huntingdon, Snyder, Adams, Bedford, Berks, Blair, Centre, Clearfield, Clinton, Cumberland, Franklin, Lackawanna, Lehigh, Luzerne, Lycoming, Montour, Northumberland, Potter, Schuylkill, Tioga, Union and York counties soon will see the nymphal skins clinging to all kinds of surfaces.

But not to worry. Although the insects are an annoyance, endlessly assaulting one’s hearing with their earsplitting monotone and flying around, bumping into things, they are just that — an annoyance.

"These insects are harmless to people, but they cause some damage to shade trees, fruit trees and high-value woody ornamental plants," Hoover said.

Birds love to eat them, and even dogs, cats, ducks and wild animals snack on them, as do carp and other fish.

“They are a source of protein to animals and fish. Their sheer numbers satiate that particular population,’’ Hoover said.

The cicadas are not harmful to small children. Nor are they harmful to swimming pools, since the cicadas are not attracted to water, although a daily skimming to remove any that may have fallen into the water is recommended. They do fall into bodies of water, where they provide food for the fish.

Damage caused by periodical cicadas occurs during egg-laying.

Mated females search for suitable egg-laying sites, which are tree branches or twigs ranging from the size of a pencil to about one-half inch in diameter. The female has a saw-like egg-laying apparatus — called an ovipositor— on her abdomen. She will cut several small pockets in the bark of a twig before depositing up to 20 eggs — a total of 400 to 600 eggs in a season. This process can cause limbs or seedlings to wilt and may provide an opening for disease, Hoover said.

The part of the twig beyond the egg-laying area usually falls off or is weakened and blows off in a windstorm. Mature trees just look messy from the dead or dying twigs.

Adult cicadas live only a few weeks, but the twig injury may be apparent for several years.

On the rare occasions when an adult periodical cicada eats, it sucks fluid from small twigs but does not feed on leaves, Hoover said

Only the males have the special vibratory organs which produce loud, strident sounds. The females are silent. Egg-laying begins about one week to 10 days after the males start to sing.

And cicadas only sing during the heat of the day, Hoover said.

“If something is singing at night, it’s not a cicada. It’s something else, (like) toads, tree frogs. If it’s at night, it’s a different group of organisms,’’ he explained.

Hoover said protective methods include covering the crowns of valuable trees with a fine mesh, being sure to tie off the covering around the base of the tree to prevent adult females from accessing the crown. Since the adults fly, they can easily bypass any other physical barrier.

He said homeowners may be wise to delay planting of trees until the adult periodical cicadas are gone in late July. But those who have already planted trees and shrubs need only cover them with netting and tie the netting securely to the base of the trunk, so that the females cannot get up to the branches and lay eggs.

“It’s more efficient. It brings about the desired effect without having to spend time and money on sprays,’’ Hoover said.

Although adult cicadas are difficult to control, Hoover suggested that nursery owners or others with trees at risk may want to apply registered insecticides around the time mating starts — about 10 days after they first hear the males singing. If a registered insecticide is

used, label instructions should be carefully read and followed.

The periodical cicada is native to North America and exists nowhere else in the world. There are six species of periodical cicada, three with a 17-year cycle and three with a 13-year cycle. Periodical cicada populations — called broods — are identified by Roman numerals. All

eight broods that occur in Pennsylvania require 17 years to reach maturity.

The cicadas surfacing this year are members of Brood XIV, which last was seen in 1991. The distribution of Brood XIV includes 24 counties in central and eastern Pennsylvania. Brood X last emerged in 2004.

There always are a few of each species that are out of synchronization with the brood and appear in other years, Hoover said.

Adult periodical cicadas are about 1 1/2 inches long with reddish eyes and orange wing veins. They are smaller than their cousins, the annual, or dog-day, cicadas usually seen and heard in the heat of late summer.

Cicada nymphs spend 17 years from 2 to 24 inches underground, sucking nutrients from plant roots.

Adults live up to four weeks above ground. Six to seven weeks after the eggs are laid, nymphs hatch and drop to the ground, where they start feeding on grass roots, gradually burrowing into the soil, not to see the light of day for 17 years.

Hoover said research on the habits of the cicadas is not a priority, since they only appear every 17 years. He said he is not seeing a lot of activity from the cicadas yet this year, but they’re there.

He cited a call from a family with hundreds of what they thought were little mushrooms sprouting in their back yard, with as many as 15 to 20 per square foot. It was a damp area, and they did look like mushrooms, but they really were cicada turrets, with their inhabitants awaiting some unseen signal to emerge.

Populations appear to be declining, probably due to such factors as sprays and loss of habitat.

For example, Hoover said, when a woodland is paved over for a parking lot, the emerging nymphs are trapped underground because they do not move laterally.

Hoover said he is concerned about the effect of the 1991 drought, when Brood XIV last emerged, on the population this year. But only time will tell.

The periodical cicadas reputedly got their “17-year locust’’ moniker from the early American colonists who had never seen them before.

The colonists were familiar with the biblical stories of locust plagues in Egypt and Palestine, and when the millions of cicadas appeared, they were reminded of the hordes of migratory grasshoppers and locusts recorded in the Bible. Some even thought a “locust plague’’ had come upon them.

The term “locust’’ is applied correctly only to certain species of grasshoppers.

When the cicadas begin their singing in a few weeks, there’s not a lot area residents can do about them — except maybe stay inside, close the door, turn up the TV and run the air conditioner to drown out their noise.

Or, for those who like the outdoors, plug the ears, grin and bear it, and be prepared to dodge low-flying cicadas now and then. This particular brood of periodical cicadas should be gone in July, and they won’t be back until 2025. Brood X, however, should reappear in 2021.

Hoover shared his own view about the phenomenon.

“The whole thing is so unique. It’s a chance for people to appreciate something unique,’’ he said.

For a free fact sheet on periodical cicadas, visit the Web at http://www.ento.psu.edu/extension/fattest/periodical_cicada.htm or contact any county Penn State Cooperative Extension office.