Landscape designer Amy Thurrott of Gumpf Gardens in Chippewa Township remembers reviewing landscape plans with a Brighton Township homeowner 17 years ago for one unusual aspect: as the two of them walked the property, they crunched scores of dead cicada exoskeletons underfoot.
“The dead bodies were like mulch,” said Thurott, who is also Gumpf’s vice president of retail operations. “I live in Beaver, where they weren’t as bad.”
Cicadas of Brood VIII, which have a 17-year cycle, will return this spring, acting as “nature’s little pruners” before dying after about six weeks of flying, mating and laying eggs until the next 17-year go-round in 2036.
Graham Pate also remembers the year 2002, not just as the year he started in the arborist business, but also the cicadas that bothered him that spring.
“I remember they were flying all around, annoying as can be,” said Pate, owner of Graham’s Tree Service in Patterson Township. “They do damage” to a tree’s young growth, but not lasting damage “where it’s going to be a real detriment to the health of the tree,” Pate said.
Brood VIII of the magicicada septendecim, one of the most common 17-year cycle cicada species, will hatch this year in a 16-county region that includes Beaver County. Sandy Feather, commercial horticulture educator for the Penn State Extension in Pittsburgh, said this species of cicada is expected to “hatch out” in mid- to late May and be active through June, possibly into July.
Cicadas are annoying for several reasons. Homeowners with ornamental and fruit trees may find that fertilized female cicadas cut slits in a tree’s new growth and lay their eggs in those young branches.
These slits can interrupt the flow of nutrients and kill the rest of the twig. Feather said she was traveling along Interstate 70 with some friends when they saw woods full of branches with dead twigs.
“The dead twigs caught our eye and made us go: ‘cicadas,’” Feather said. Sure enough, when the motorists stopped, they saw the telltale holes in the ground where the cicadas had hatched and flown away, as if an aerator had regularly pierced the ground.
To prevent damage to delicate and expensive Japanese maples in the Gumpf nursery, Thurott said employees will place them in the nursery’s greenhouse, and put rhododendrons, which are too small for cicadas to choose, outside.
“They live a lot longer than some of our companion animals,” Feather said, though nearly 17 years of that life is underground, where the larvae stay until they mature. There are six species of cicada, three that hatch every 17 years and three that have a 13-year cycle.
“They’re unique to the world, and they’re native to North America,” specifically the Northeast, where they will annoy their human counterparts with a loud buzzing sound, Feather said.
The almost otherworldly buzzing, another source of human aggitation, emanates from the adult male cicada, which signals the smaller, quieter female through special organs called tymbals located on the first segment of their abdomens.
In areas where many cicadas hatch, the sound effects can be almost maddening. The cicadas do not eat during their approximately six-week period of adulthood but fly around looking for mates.
Once fertilized, the female then lays the eggs by cutting those slits in twigs and laying around 20 eggs there – as many as 600 total in various branches, said Robert Davidson, collection manager of the invertebrate zoology section of Carnegie Museum of Natural History in Pittsburgh.
Once the eggs hatch, the nymphs drop to the ground and burrow into the soil, from a depth of a couple of inches to two feet deep. There they pierce the roots of the tree and feed on its nutrients for 17 years until reaching maturity. They may molt four or five times over that period and may go deeper, Davidson said.
The nymphs that hatched from eggs laid in 2002 are expected to emerge this year and crawl up nearby trees. Then their exoskeleton will split, and an adult will emerge “like a softshell crab, with its wings crinkled up,” Davidson said.
The exoskeleton then hardens, and the wings unfold “like an origami kite.” It’s then time for the male cicadas to produce their distinctive, loud buzz, which they use to attract the females, who only click to show their interest.
And while the clumsy flying patterns of the adult cicadas can also be annoying – the sound of lawn mowers and other loud tools attracts the lumbering fliers – the insects do not sting or bite.
“They’re not going to hurt you,” Davidson said.
While predictions of how many cicadas will hatch in Beaver County are hard to come by, Davidson said as many as 1 million to 1.5 million cicadas per acre can hatch in undisturbed wooded areas once the soil reaches a temperature of 64 degrees Fahrenheit.
So many cicadas hatch around the same time to produce what entomologists call “predator satiation” – such huge numbers of insect offspring that no group of predators could possibly eat them all. Birds, lizards, frogs, toads and even fish eat cicadas, Davidson said.
Matt Erb, director of urban forestry at Tree Pittsburgh, a tree advocacy group, and a graduate of Beaver Area High School, said he was working in New York City in 2002, where “they were very loud. There would be swarms of them buzzing by all the time,” said Erb, who earned his degree in urban forestry from Penn State in 2003.
Erb said it would be difficult to predict numbers or impacts of cicadas this year.
“We have a lot of wooded slopes where there is probably a healthy population of cicadas,” he said.
Some trends that might discourage cicadas are pesticide treatments some lawn services already use on customers’ lawns, as well as treatments some people are using on ash trees to prevent damage by the emerald ash borer. “So you may see a reduced cicada population (this year). But I’m not encouraging (people) to use pesticides,” Erb said.
Neither does Feather, who said cicadas can be especially damaging to fruit and nut orchards, which if commercial operations “are making regular insecticide applications” to will prevent cicada damage.
And Thurott said pesticides are only effective “if you shoot right at the cicadas … A physical barrier is the only way” to prevent cicada damage in young trees.
Those physical barriers “are lightweight and are permeable to sunlight and rain, but insects can’t penetrate them,” Feather said. The important thing is to wrap the tree all the way to the ground so insects can’t fly up under the blanket and lay their eggs anyway.
Though they are graceless aviators, Feather is excitedly looking forward to the hatching of this year’s brood of cicadas.
“I’m 62; I don’t know how many more times I’ll see them,” Feather said. Or hear their distinctive, maddening buzz.