This Spring Will Bring Billions Of Cicadas In Rare Brood Convergence

Fascinating, harmless, yet often annoying to outdoor workers, cicada swarms will be emerging in Illinois, Missouri, and parts of the Southeast.

A Brood X cicada that emerged in 2021. Photo: AdobeStock/Michael

Before the winged insects have even appeared, at least one major news outlet is already reporting: 2024 belongs to the cicadas. Why? For the first time since 1803, a 17-year brood and a 13-year brood will emerge from their underground slumber at the same time, creating billions of cicadas starting in late April and early May this year.

Brood XIII is shown by blue dots, and Brood XIX is shown with red dots. Credit:

The 17-year Brood XIII will emerge in northern Illinois, while the 13-year Brood XIX will emerge in southern Illinois, Missouri, and parts of Southeastern U.S. (see map). The dual emergence of these two broods only occurs once every 221 years. The last time it happened Thomas Jefferson was President of the U.S., and Lewis and Clark had started their exploration of the Louisiana Purchase.

A scene in a Cincinnati Park during Summer 2021 when Brood X emerged. Photo: AdobeStock/Cavan



This information comes from, created by Dr. Gene Kritsky, an entomologist at Mount St. Joseph University in Cincinnati, OH and author of “A Tale of Two Broods,” a book about this year’s dual emergence, and “Periodical Cicadas: the Plague and the Puzzle.”

Landscaper reaction to the expected masses is mixed on social media. Some see it as money making opportunity for yard clean ups, while others who experienced the 2021 Brood X numbers say lawn pros should be prepared for annoying swarms that are attracted to the sounds of mowers and small engines—no doubt for their similarity to the cicada mating call. They say workers wore hoodies and were covered in the insects during the height of Brood X’s emergence.

WalkingPod mesh cicadas
A wearable pod from WeatherPod could help keep 2024’s cicada swarms from bugging you.

Of course, one can prepare for the hordes with this product that came to Turf’s attention during the Brood X invasion: wearable pods from WeatherPod®! See the full article here.

While some might be tempted to spray pesticides, it’s not really an effective control measure. According to the Environmental Protection Agency (EPA), “Pesticides are generally ineffective in keeping cicadas away. So many emerge at once that more will inevitably move in. Spraying also doesn’t make sense because cicadas are generally harmless. Applying pesticides to control them may harm other organisms, including animals that eat cicadas. Pesticides can be harmful to other non-target, beneficial insects. Pets and people may also be unnecessarily exposed to pesticides.”

Dr. Kristsky says adult cicadas do not sting or bite humans, or carry diseases. “They are not pests and do not need to be killed,” he writes.

While cicadas can harm young trees when eggs are laid in the tree’s new growth, spraying is still not an effective measure. Instead, to protect young trees, loosely wrap the branches with cheesecloth or netting with ¼” or smaller openings to prevent egg laying, recommends Dr. Kristsky. Cicadas cannot harm larger, more established trees and they will not eat leaves, flowers, fruits, or garden produce, according to the EPA.

In fact, periodical cicada years are quite beneficial to the ecology of a region, say experts. Their tunnels for emergence act as natural soil aeration. Adult insects provide a food bonanza to all sorts of predators. Egg-laying in trees is a natural pruning that results in the tree producing more flowers and fruit in the following year. Finally, after the cicadas die, their decaying bodies contribute a massive amount of nitrogen and other nutrients to the soil.

After adults have emerged from nymphal exoskeletons, the skeletons often remain clinging to leaves, tree trunks, branches, etc. The massive emergence of a brood of periodic cicadas (Magicicada sp.) leaves perhaps hundreds of skeletons in an average tree. These remains are from the Brood X (10) emergence in the eastern U.S. in 2004. Photo: AdobeStock/Gerry

Here are more interesting cicada facts from and Dr. Kristsky:

  • Periodical cicadas were first recorded by the Pilgrims at Plymouth Colony in 1634, but they were known to the Native Americans for centuries prior to European contact. Brood X was first reported in 1715 in Philadelphia.
  • There are three species of 17-year cicadas. There are four species of 13-year ones.
  • Groups that share the same emergence years are called broods, usually given a group number in Roman numerals. Charles Marlatt, an entomologist working for the Department of Agriculture, designated that all the cicadas that emerged in 1893 and at 17-year intervals thereafter as Brood I [one]. Cicadas that emerged in 1894 were called Brood II [two] and so on. (The cicadas that emerged in 2021 belonged to Brood X).
  • Not all cicadas count the years correctly. In 2000, based on collections of underground nymphs, Dr. Kritsky predicted that thousands of 17-year cicadas would emerge four years early. It did occur and in five locations the numbers were so great the cicadas sang, mated, and laid eggs. The question then became: will these early offspring keep a 13-year life cycle or shift back to 17 years? In 2013, a few hundred cicadas emerged, but the adults were all eaten by predators. In 2017, when more offspring of the early 2000 cicadas emerged, they were joined by Brood X cicadas that were emerging four years early. This is now a new population of Brood VI in SW Ohio, but th world will have to wait until 2034 to see if this population becomes permanent.
  • Only the male cicadas sing. It’s easy to tell male from female cicadas. Turn the cicada over: the female will have a groove in which is found the ovipositor; the male’s abdomen will terminate with a square shaped flap.
  • Adult cicadas do not eat solid food, but do drink fluids.
  • Periodical cicadas are often incorrectly called locusts. Locusts are grasshoppers and cicadas are more closely related to aphids.




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