Cicada swarm: What you need to know about the incoming invasion

This year, trillions of periodical cicadas are emerging in numbers not seen in decades and possibly centuries. 

Two periodical cicadas broods are emerging at the same time: the 13-year Brood XIX, primarily in the southeastern U.S., and 17-year Brood XIII, primarily in Illinois and its surrounding states. A cicada “brood” refers to a group of cicadas that always emerge at the same time and can include multiple species of periodical cicadas. 

As cicada season begins or nears in parts of the U.S., online search data show many people are wondering how to protect their yards from the insects. They are asking if cicadas will eat their vegetable garden and whether the insects can harm trees. VERIFY reader Alex also texted us to ask if pesticides or insecticides will keep cicadas away. 

We’re VERIFYING the answers to four questions about cicadas and your yard. 

THE SOURCES

• U.S. Environmental Protection Agency (EPA)
• Smithsonian National Museum of Natural History
• University of Connecticut
• University of Maryland’s Cicada Crew, a team of entomologists providing information about cicadas
• McKay Nursery
• Hannah Burrack, Ph.D., professor and chair at Michigan State University’s Department of Entomology
• Spencer Campbell, plant clinic manager at The Morton Arboretum near Chicago

WHAT WE FOUND

QUESTION #1

Will cicadas eat the vegetables or flowers in your garden?

THE ANSWER

Cicadas won’t eat the vegetables or flowers growing in your garden, according to the Environmental Protection Agency (EPA) and experts who spoke to VERIFY. 

The insects don’t eat plant leaves. Instead, they get their nutrients by consuming small amounts of sap from trees and shrubs while they are above ground, the EPA says. 

The insects have “tiny, straw-like mouthparts that they use to tap into the sap” in these woody plants, Hannah Burrack, Ph.D., professor and chair at Michigan State University’s Department of Entomology, said. 

Because of their limited diet, cicadas won’t “damage anything that we might be interested in harvesting or eating that’s growing on plants,” Burrack added. 

RELATED: No, this isn’t the first time since 1803 that two broods of cicadas emerged at once

QUESTION #2

Can cicadas harm some types of trees?

THE ANSWER

Cicadas can damage young or newly planted trees, but experts say there are ways to protect them. 

Female cicadas make slits in tree branches and lay their eggs there, the Smithsonian National Museum of Natural History explains. They prefer small twigs or branches that are about as thick as a pencil, Burrack and Spencer Campbell, plant clinic manager at The Morton Arboretum near Chicago, said. 

If many female cicadas lay their eggs in the branches of trees, it may cause the tips to wilt and die, a team of entomologists at the University of Maryland called the Cicada Crew says. This isn’t a concern for healthy trees and shrubs that are larger and well-established, according to our experts. 

But younger or newly planted trees and shrubs are at risk of damage during the egg laying process.

To protect those young or newly planted trees, our experts recommend covering them with a protective netting like mesh or tulle. The openings should be no larger than one-quarter of an inch across, Campbell said. 

The Morton Arboretum also recommends closing gaps in the netting with binder clips, clothespins or staples, and gathering the fabric around the trunk as close to the ground as possible. 

People can remove the coverings from their more vulnerable trees when the cicada event wraps up in about four to six weeks.

QUESTION #3

Will cicadas harm your lawn?

THE ANSWER

Cicadas are unlikely to damage your lawn and could actually do some good, according to Campbell and Burrack. 

A few weeks before they emerge from the ground, cicadas nymphs build exit tunnels to the surface. The holes that the cicadas exit from are usually about a half-inch in diameter, according to the University of Connecticut.

These exit holes can aerate your lawn and improve water filtration into the soil, Burrack explained. 

Cicadas benefit plants in other ways, too. After the adults die off, their bodies decompose and add valuable nutrients to the soil, Burrack and the EPA say. 

QUESTION #4

Should you use pesticides or insecticides to get rid of cicadas? 

THE ANSWER

Experts do not recommend using pesticides or insecticides to get rid of cicadas. The EPA says pesticides are “generally ineffective” in keeping cicadas away anyhow. 

“You’re not going to get a whole lot of benefit from trying to manage with a chemical material in this case,” Burrack said. “The populations are just too big, they’re going to be active for too long a period of time to get long-term control, and the actual impact of them is not going to justify the effort that you would have to put into using a chemical pesticide.”

Cicadas are not dangerous and can benefit the environment. For example, the insects are a valuable food source for birds and other predators, the EPA says. 

Pesticides and insecticides can also harm those animals that eat cicadas, as well as other pollinators like birds, bees and butterflies. 

Pets and people may be unnecessarily exposed to pesticides, too, the EPA adds. 

The Associated Press contributed to this report. 

This story is also available in Spanish / Lee este artículo también en español: Verificamos 4 datos breves sobre las cigarras en tu patio

RELATED: Yes, cicadas are safe to eat for both you and your pet