While the first full-scale emergence of cicadas in 17 years has yet to arrive in Illinois, several cicadas have started to emerge across the Chicago area, and more are on the way.
“The periodic cicada has been emerging for the past week and a half,” Stephanie Adams, a plant pathologist at the Morton Arboretum in Lisle, said Tuesday of Brood XIII, adding that it will soon spread throughout the Chicago area. “We find them both in the landscape here and in the forests to the east.”
For the past 17 years, billions of periodic cicadas from Brood XIII have been living underground in the Chicago area, sucking fluids from plant roots. He is expected to fully emerge from mid-May to June, and once he has dug a hole, he is expected to emerge “everywhere.”
“It's really impossible to escape them,” said Allen Laurence, associate curator of entomology at the Peggy Notebart Museum of Nature in Chicago, adding that the insects are particularly vulnerable to emerge from branches and leaves, especially on and around trees. He said it was expected that cicada shells would “pile up” after eating the liquid. woody shrub.
In general, cicadas are not “specific,” meaning they use a variety of trees and shrubs as hosts, and are known to lay eggs on their favorite plants.
“Most cicadas have a wide range of host plants and are considered versatile, but like any living thing, they have preferences,” the Morton Arboretum's post said.
According to the arboretum, cicadas “tend to dislike” plants whose sap or rubber can prevent eggs from hatching. Some of these trees also include conifers such as pines, spruces, and firs. Those trees could also include cherry blossoms, peach trees, plum trees and persimmon trees, according to the arboretum.
The arboretum says the insects are not picky, but are known to lay their eggs in certain trees, including oak, maple, hickory, apple, birch, dogwood, linden, willow, elm, ginkgo and pear trees. It is said that there is
“Cicadas may also lay eggs on some shrubs such as roses, lilacs, and forsythia,” the arboretum said.
According to arboretum records, the plants most affected during emergence 17 years ago were maple, cherry, rowan, hawthorn, willow, rowan, oak, pear, rose, privet, poplar, serviceberry and beech. .
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The first cicadas emerge about two weeks earlier than the historical average, Adams said. Soil temperature, mulch, and turfgrass all affect cicadas differently, so this will continue to be a sporadic event. For example, the soil near paved roads is warmer, so cicadas there are expected to emerge earlier.
“There's always a gradient in everything in biology,” Adams continued. “So there are always some who show up early, and some who show up a little later.”
How to protect trees from cicadas
Adams said cicadas are generally harmless. They do not sting and do not have stingers, so they are beneficial to the environment. But they can damage vulnerable small trees and shrubs, Adams said.
Adams said young plants, two to three years old, are most at risk, as are smaller plants with branches less than 2 inches in diameter. Adams said the damage caused by female cicadas when they lay eggs may be irreversible.
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“That damage is caused when the female starts laying eggs,” Adams explained. “She has special organs that cut into plants, trees and shrubs and lay her eggs inside the thin bark.”
According to the arboretum, one way to protect trees and shrubs is to use tulle as a wrap or protective barrier. Tulle material is especially recommended as it is breathable and allows sunlight to penetrate the plants.
“What you're looking for is netting that's less than a quarter-inch wide. Any larger and the cicadas will slip through it, defeating the purpose of protecting them,” said Plant Clinic Manager Spencer Campbell. .
Homeowners are advised to begin protecting seedlings as early as possible and continue to wrap them until mid-June, when emergence is complete.
Can cicadas damage trees?
Adams said cicadas are generally harmless. They do not sting and do not have stingers, so they are beneficial to the environment. But they can damage vulnerable small trees and shrubs, Adams said.
Adams said young plants, two to three years old, are most at risk, as are smaller plants with branches less than 2 inches in diameter. Adams said the damage caused by female cicadas when they lay eggs may be irreversible.
more: Will the 2024 cicada explosion mean more bees killing cicadas? Here's what experts say
“That damage is caused when the female starts laying eggs,” Adams explained. “She has special organs that cut into plants, trees and shrubs and lay her eggs inside the thin bark.”
According to the arboretum, one way to protect trees and shrubs is to use tulle as a wrap or protective barrier. Tulle material is especially recommended as it is breathable and allows sunlight to penetrate the plants.
“What you're looking for is netting that's less than a quarter-inch wide. Any larger and the cicadas will slip through it, defeating the purpose of protecting them,” said Plant Clinic Manager Spencer Campbell. .
Homeowners are advised to begin protecting seedlings as early as possible and continue to wrap them until mid-June, when emergence is complete.
Are insecticides effective against cicadas?
A post from the City of Lake Forest advises residents to “avoid planting young trees less than 2 inches in diameter” and to cover them with netting. The city advised residents to avoid using pesticides.
According to the Environmental Protection Agency, pesticides are “generally not effective in keeping cicadas away.”
“With so many cicadas emerging at once, more will inevitably come in,” the agency said. “Spraying is also pointless because cicadas are generally harmless. Spraying insecticides to get rid of cicadas can harm other organisms, including animals that eat cicadas.”
Can I limit the number of cicadas in my garden?
Frank Meek, technical services manager for pest control company Orkin, told NBC that pest control companies in Chicago typically do not treat cicadas because they are not a threat to people, animals or property.
Additionally, chemical treatments are generally ineffective due to the short lifespan of cicadas, Meek added.
“Cicadas are an important part of the food chain, providing food for birds, moles, raccoons and some frogs,” Meek said. “It's important for humans to leave cicadas alone so that other animals can benefit from their food source.”
Cicadas are not considered pests, Meek said. However, they have been known to burst into homes uninvited.
“Cicadas are strong but clumsy flyers and can accidentally fly into your home if a window or door is left open,” Meek said. “However, indoor infestations do not occur because cicadas cannot breed indoors.”
Meek said cicadas found in yards and gardens can be removed “gently” by hand. While Orkin doesn't advise on cicada pest control around homes, the company says there are additional layers of defense homeowners can take to keep cicadas away.
“Homeowners can also prevent cicadas from taking up residence in trees and bushes by wrapping the base of trees with foil or barrier tape,” Meek says. “This prevents cicadas from climbing trees and bushes to feed and lay eggs.”
Still, experts say it may not be worth the trouble. After all, there will be billions of them.
“The last thing you want to do is try to remove them from areas that are home to billions of animals,” said Alan Laurance, associate curator of entomology at Chicago's Peggy Notebaert Museum of Nature. .
This year's emergence has just begun, but is expected to reach its peak in the coming weeks.
“You can't stop them,” says Allen Laurence, associate curator of entomology at Chicago's Peggy Notebaert Museum of Nature. “They're here. It's temporary and they can't really escape.”
