What Are Cicadas?

Last updated: 5/11/21
Estimated Read time: 5 minutes

Have you ever stood outside on a late summer night and heard a loud buzzing all around? What you were hearing was the noisy mating call of cicadas, which are large flying insects active between mid-May and mid-June. While cicadas are usually just quiet background noise, this summer they will be the loudest they have been in 17 years.

Is 2021 a Cicada Year?

Yes, 2021 is a cicada year! As there are multiple broods of periodical cicadas that appear at different 17-year intervals, they are organized by number. Maryland is home to several broods, but the largest is Brood X, which is set to emerge from the ground when the ground temperature gets to about 64 degrees. The first few cicadas may come out in late April, but the bulk of the emergence will likely happen in the second half of May. A little rainfall can help trigger the emergence. Brood II can also be found in southern Maryland and will emerge again in 2030.

What Do Cicadas Look Like?

While species vary in color and size, cicadas can easily be recognized by their protruding eyes and the semi-transparent wings, which cover their large bodies.

The two common types of cicadas found in the eastern United States are the dog-day and the periodical cicada:

• When fully grown, the dog-day, or annual cicada, is about 1.5 to 2 inches long with a black or brown body and green or white body markings. This species is the more common, as it occurs every summer.
• Adult periodical cicadas are slightly smaller than dog-day cicadas, with black bodies, reddish-brown eyes, and orange wing veins. They can also be identified by a small, black “W” marking on the front wings. Periodical cicadas are also known as the “17-year locust” (even though they are not locusts), as they emerge every 17 years in large groups called broods.

Do Cicadas Hibernate?

Contrary to popular belief, cicadas do not hibernate. Instead, they live underground for 2 to 17 years, during which time they are active by tunneling and feeding.

In early April, you may find holes in the ground about the size of your index finger around tree trunks on your property—these are the cicadas’ escape tunnels. You may also see signs of animals digging under trees. Raccoons, foxes, and skunks know that cicadas are ready to make a jailbreak and they’re already beginning to excavate the ground to eat them.

Where Do Cicadas Come From?

While annual cicadas can be found around the globe, periodical cicadas can only be found in North America. Periodical broods are most common in the central and eastern regions of the United States, with some areas, such as Maryland, hosting multiple broods.

Why Are Cicadas So Loud?

The loud buzzing noise you hear cicadas make during the summer is the mating song that male cicadas use to attract females. Males produce this unique sound by rapidly flexing their tymbal, the drum-like organs located on the sides of the mostly hollow abdomen of the insect.

What Do Cicadas Do?

To understand how cicadas are beneficial, it helps to understand their life cycle:

• After a young cicada emerges from its egg laid on small tree branches, it feeds off of xylem, the water transporting tissue of trees. While adult cicadas have distinctive coloring, both of these species look similar to a termite or small white ant shortly after hatching.
• Once it’s ready, the young cicada crawls to the ground and digs until it finds tree roots on which to feed.
• After living underground for 2 to 17 years, depending on the species, the wingless cicadas emerge as nymphs and climb onto a tree to shed their exoskeleton and reveal their adult skin.
• Once their new exoskeleton has hardened, cicadas begin their brief adult life of 2 to 6 weeks.

Can Cicadas Hurt You?

No, cicadas pose no threat to people or your pets. Unlike other insects, cicadas do not sting or bite. If handled, adult cicadas may make a loud buzzing noise, though they will not attack. Most people just find cicadas unattractive, loud, and a temporary nuisance.

Are Cicadas Good for My Lawn?

During their lifecycle, cicadas have an overall positive impact on their environment. They naturally prune trees, aerate the soil when digging through the ground, and upon their death, provide nitrogen to growing trees.

Can Cicadas Damage Plants?

Though mostly harmless, cicadas have egg-laying habits that may cause minor damage to plants. Females use an appendage, called an ovipositor, to cut small slits in branches into which they deposit eggs. If a branch has too many slits, it may break off or hang down, a state commonly known as flagging.

How Do I Protect My Trees From Cicadas?

While the damage caused by cicadas is usually not serious, repeated injury during brood years can stunt the growth of or even kill young or newly planted trees. Common methods of protecting your trees include:

• Wrapping tree trunks and large branches in barrier tape, such as foil or sticky bands.
• Covering small trees in plastic mesh or netting with openings smaller than ¼ inch.

We recommend covering plants for about 6-8 weeks, beginning at the time that cicadas emerge. You can always contact your local lawn and tree care company, Blades of Green, to assist with any damage!

Do Cicadas Bring Other Pests?

The abundance of cicadas may very likely bring unwanted visitors to your yard – in fact you may already be noticing damage caused by these animals trying to dig the cicadas up from the ground for a tasty treat. Cicadas are commonly eaten by birds, bats, spiders, snakes, frogs, and even fish, however, there is one animal that may be a larger concern for homeowners as it relates to the cicadas: Moles. Anytime there is an abundance of a food source, like that of Brood X, there will be an increase in mole activity. Moles in your yard can:

• Destroy the roots of plants
• Give easy access to other rodents on your property
• Damage building foundations
• Create pathways and pools of water