May 30, 2004 By James Pletcher Jr. 7 min read

While there may be some spotty outbreaks, Fayette County for the most part will miss this year’s cicada onslaught. But the bugs, commonly referred to as locusts, will invade nearly two-thirds of Pennsylvania’s counties, wreaking havoc on fruit and other softwood trees.

Although they pose no threat to people or animals, the cicadas damage trees when the female carves a slit into a branch or limb with a saw like appendage. She deposits her eggs in the opening, and that wound can allow other parasites to enter and possibly kill the tree.

“We aren’t scheduled for them until 2016,’ Bill Gallagher, Fayette County Extension Service agent said.

“We had them last in 1999. We got them worse here because we are at the foot of the mountain. People could spray them and spray them but there were so many there wasn’t much to do.

“Our area was hit very hard that year,’ he said.

“We had planted a bunch of trees out at the fairgrounds (Fayette County Fairgrounds on Route 119 north) that year and we had to do a lot of pruning the next year. There was a lot of deadwood. We had to replace a good many of those trees,’ he said.

Gallagher explained that some areas of Fayette in 1999 might not have been hit as hard. He added there may be spotty outbreaks in areas of Fayette but they won’t reach the magnitude of the past invasion.

“What the females do when they cut into the tree is leave something like a scar. A lot of people think that scar will heal but it can still allow things to get in that will kill the limb or the tree.’

However, Gallagher said there was no available survey of the total in economic damage the insects did in this region.

“We do not keep records of economic damage for cicadas; indeed, I doubt if that information is available even if we tried to maintain such records,’ Jim Stimmel, survey entomologist, Division of Plant Protection Bureau of Plant Industry, Pennsylvania Department of Agriculture in Harrisburg, said.

“Cicadas do not produce economic damage (i.e., crop yield loss) per se. The ‘damage’ they cause is largely aesthetic damage to trees rather than a loss of a food or fiber product. They affect deciduous trees and woody shrubs, and do not cause damage to small grains, forage, or vegetable crops.

“There may be some minor impact to the ornamental plant/nursery industry, but that has never been quantified.

“In short, neither we (Pennsylvania Department of Agriculture) nor Penn State University Cooperative Extension has any value figures for economic loss caused by periodical cicadas. Losses are considered insignificant,’ he said.

“The question about distribution was answered correctly by your local extension folks: Fayette, Greene and Washington counties are the three Pennsylvania counties harboring Brood V of the periodical cicada. Our records indicate that this brood emerged in 1999 and will reappear in 2016. These counties do not contain any Brood X cicadas, which are emerging in eastern Pennsylvania right now,’ Stimmel added.

Gregory Hoover, Penn State Extension entomologist, said that nearly two-thirds of Pennsylvania’s counties are being invaded this year.

He said the swarm of periodical cicadas “actually is not an invasion at all, because these insects have been here all along – beneath the soil – waiting to see daylight for the first time in 17 years. When they emerge in forested areas you won’t be able to miss them,’ he said.

Periodical cicadas are native to North America, Hoover explained in a paper on the bugs, and exist nowhere else in the world.

“There are seven species of periodical cicadas, three with a 17-year cycle and four with a 13-year cycle. Those found in Pennsylvania are 17-year periodical cicadas.

“Periodical cicada populations, called broods, are identified by Roman numerals. The cicadas surfacing this year are members of Brood X – sometimes referred to as the ‘great eastern brood’ – which last was seen in 1987. Brood X is distributed throughout parts of 15 states in the Mid-Atlantic, South and Midwest, including 40 counties in Pennsylvania: Adams, Bedford, Berks, Blair, Bucks, Cambria, Carbon, Centre, Chester, Clinton, Columbia, Cumberland, Dauphin, Delaware, Elk, Franklin, Fulton, Huntingdon, Juniata, Lackawanna, Lancaster, Lebanon, Lehigh, Luzerne, Lycoming, McKean, Mercer, Mifflin, Monroe, Montgomery, Montour, Northampton, Northumberland, Perry, Philadelphia, Schuylkill, Snyder, Somerset, Union and York.

“These insects are harmless to people,” Hoover said. “They do not bite or sting, but they can damage shade trees, fruit trees or high-value ornamentals.”

Hoover said a female cicada will cut several small pockets in the bark of a twig before depositing 400 to 600 eggs. This process can cause twigs or seedlings to wilt and may provide an opening for plant diseases.

Adults live only a few weeks, but the twig or branch injury they cause may be apparent for several years.

“Periodical cicadas are sometimes called nature’s pruners,” Hoover said. “To avoid damage to young plants, homeowners and ‘green industry’ professionals planning to plant new deciduous woody ornamentals this season may want to wait until fall. You also can cover the crown of valuable trees with a fine mesh until the adult cicadas are gone, usually in early July.”

Hoover said cicadas can damage fruit trees in another way.

“After entering the ground the nymphs eventually attach themselves to the roots of the fruit tree, insert their needlelike mouthparts into the roots, and feed on nutrients that would otherwise help the tree grow and produce fruit.

“Feeding by hundreds or even thousands of these insects on a tree root system for 17 years probably affects the tree productivity, although this has never been fully documented,’ he said.

Hoover explained that registered insecticides can be applied around the time mating starts, which is about 10 days after they begin “singing,’ but adult cicadas are “difficult to control.’

Adult periodical cicadas are about 11/2 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, he said.

Periodical cicada nymphs spend 17 years from 2 to 24 inches underground, sucking nutrients from plant roots. In late April or early May, they burrow to within an inch of the soil surface, where they wait for an undetermined signal to emerge. When the time is right, Hoover said, usually in late May or early June, nymphs exit the soil through half-inch holes and climb a foot or more up trees or other objects. Within an hour, they shed their last nymphal skin and become adults.

“Adult cicadas are clumsy flyers, often colliding with objects in flight. Males begin their constant singing shortly after they emerge, but the females are silent. When heard from a distance, the cicadas’ chorus is a whirring monotone, sometimes described as eerie-sounding,’ he said.

Adults live up to four weeks above ground. Six to seven weeks after the eggs are laid, nymphs hatch and drop to the ground. There, they enter the soil, to begin their 17-year hibernation.

Other creatures that may benefit from the cicadas are fish, turkeys and some wildlife that will eat the insects.

Cicadas are also high in protein, according to the College of Mount St. Joseph in Cincinnati, Ohio. In a fact sheet, the college said periodical cicadas are best eaten when they are still white (teneral), and they taste like cold canned asparagus.

“Like all insects, cicadas have a good balance of vitamins, are low in fat, and the females are especially high in protein. They are also Atkins friendly,’ the fact sheet said.

More information on ciacadas is available by contacting the Fayette Extension Service office at 724-438-0111 or visiting the Penn State Department of Entomology Web site at www.ento.psu.edu.