Invasion of the Brood X Cicadas

Brood Cicadads

Cicadas on a tree branch in 2017. Image via Cicada Safari.

Coming soon to trees and shrubs near you:  Invasion of the Brood X Cicadas

If you live in one of the 15 states or the District of Columbia, you may already be seeing the beginning of the Brood X cicada emergence. The show stars one of the largest swarms of cicadas in the world – hundreds of billions will emerge in the next couple of weeks, as many as 1.5 million per acre at the epicenter – Maryland, D.C., and northern Virginia.  After surviving 17 years underground, a cicada lives only four to six weeks above ground. The large presence of cicadas will likely last only about a couple of months. Cicadas are native to North America and beneficial to forests and wildlife - they are not really invaders at all, just visitors to the above ground world.


Cicadas Brood

Accuweather (


After 17 years of living underground, cicada nymphs are beginning to emerge from the ground, tunneling up leaving holes and sometimes mud chimneys.  Males emerge before females.  Once above ground – usually just after sunset - the soft nymphs start to climb anything vertical.  They exit the shell through the back and emerge soft and white with soft white wings and red eyes.  It can take four to six days for the new skin to harden and turn black and for the wings to stiffen up.  The males then fly to the treetops (and everywhere else) and begin their mating call – loudly.  During the peak of the swarm, the noise produced by the males can top 100 decibels – louder than a chainsaw, a jet overhead, or a leaf blower (recordings of periodical cicadas can be found at Cicada Mania). 

Cicada Lifecycle


Credits for pictures in lifecycle graphic: 


There are many good pictures, maps and videos of cicadas through the lifecycle available online at Cicada Mania,  Cicada Safari, and National Geographic.

Male cicadas die after mating.  Female cicadas are what may cause damage to young trees or shrubs.  They make a line of 5 to 20 slits in tender branches, where they lay 200-400 eggs.  The eggs hatch in six to seven weeks and the tiny nymphs drop to the ground and tunnel until they reach tree or plant roots that they can feed on for the next 17 years.  This feeding does no harm to the trees or plants.

They do little harm

Cicadas do not bite or sting.  They arrive in large numbers and can be annoying if you live near the epicenter of a brood - the noise can be loud enough to damage your hearing, they fly into and land on you, and they fly into your windshield.  Only young or newly planted trees with branches the diameter of your little finger, where females lay their eggs, are likely to be seriously injured.  Healthy mature trees and shrubs may have flagging – where the ends of branches may die.  There is usually little long-term damage, rather it’s a sort of natural pruning. Pesticides are of no use against periodical cicadas, so the only recourse is to wrap a small tree or woody vine in netting with mesh one centimeter or smaller to keep the cicadas from laying eggs. They do not often affect annuals or perennials (unless they are woody) – they may use them while shedding their shell or allowing their bodies and wings to harden.


“Flagging” caused by cicadas (

They feed animals and forests

Cicadas are eaten by birds, raccoons, dogs, opossums, skunks, and pretty much all other woodland creatures.  Some people who fly fish use them as bait.  Because there are so many cicadas in a brood, the numbers are not affected by being consumed by other animals and at a certain point, the animals appear to stop eating them.  Some people say they are good to eat (cooked, of course) and the description of flavor ranges from white asparagus to shrimp.  Many Native American Onondaga people in New York state believe that their ancestors ate them to survive after their crops had been burned and their villages destroyed, some eat them now sauteed in butter following Onondaga tradition. The empty exoskeletons and carcasses feed the forest and the nymphs underground help aerate the soil.  

Cicadas have been around a while

Cicadas have been around for about five million years.  Their presence was recorded by settlers and.  There are over 190 varieties (including species and subspecies) species of cicada in North America, but only the seven Magicicada species have developed into periodical emergences.  Brood X includes three species:  Magicicada septendecim, Magicicada cassinii and Magicicada septendecula.  The three species congregate on different trees and have a different male song.

Citizen Science opportunity


If you want to help map the 2021 emergence of Brood X, download the free app from the Apple app store or Google play.  Take a photograph of a periodical cicada and submit it to Cicada Safari. Once the photo is verified, it will be posted to the live map. Cicada Safari was created by Dr. Gene Kritsky working with the Center for IT Engagement at Mount St. Joseph University in Cincinnati, OH.



If you can’t be outside to grill

If you live where Brood X is loudest, you may not want to cook or dine outside.  It may be just too darn loud!  Never fear, Sizzlefish has many fine recipes for seafood that you can prepare without a grill or campfire.  If you’re not going outside because of the cicada invasion, you may not be getting as much exposure to sunshine and Vitamin D as you normally would.  The Dietary Guidelines for Americans says that we should get most of our nutrients from foods that contain vitamins, minerals, dietary fiber, and other substances that benefit health.  Seafood is a good source of vitamin D, especially Chilean sea bass, salmon, tuna, mackerel, and sardines, although many other fish and shellfish provide a generous percentage of RDA.  Sea bass is especially high in vitamin D, providing approximately 225 IU per 100g (3.5 oz). Other foods that are high in calcium include spinach, kale, okra, collards, soybeans, and white beans.  If you are not getting enough vitamin D from your regular diet, you can include fortified foods (e.g., fortified milk, cereal, yogurt, orange juice, etc.) and/or dietary supplements.

Sizzlefish provides you with pure natural fish portions along with tips and recipes for quick easy preparation. 

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