Are you braced for the Great Cicada Emergence of 2024? The cicadas are already starting to make some serious noise here in Alabama. My kids have sent me pictures of carapaces covering the brick walkways of their college campus, and a friend has shared videos of just how loud things are at his house. All seems fairly quiet at my house – for now – but it’s good to know what to watch out for and how it might affect my garden this year. If you live in the eastern United States, there’s a good chance you’re pretty curious about what’s in store, too. Let’s take a look!
What Are Periodical Cicada Broods?
Although there are thousands of cicada species, only 9 are what are known as “periodical” cicadas. Of these 9 species, 7 live in the eastern United States. These insects get their name because of the long periods of time during which they disappear underground. At the end of the cycle, they crawl out of the ground and indulge in a frenzy of mating and egg-laying that lasts until the adult cicadas die. They do this in “broods” – regional groups of these species that emerge together – simultaneously. Each Roman numeral matches a specific year and location, which simplifies things for entomologists who are tracking them. However, it can be confusing for most of us, so I’ll also add the colloquial names to help.
Where Will Cicadas Emerge in 2024?
In 2024, two different cicada broods are emerging from their underground period. The first is Brood XIII, and it is also known as Northern Illinois Brood. These cicadas show up every 17 years and have been spotted in northern Illinois of course, but also in parts of Indiana, Iowa, and Wisconsin. The other brood is called Brood XIX, or the Great Southern Brood, but they have a range that is wider than the Southern US. The cicadas are on a 13-year cycle and can be found in Maryland, Virginia, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Tennessee, Kentucky, Arkansas, Oklahoma, Missouri, and Illinois.
The noisiest spot to be in the US in the coming weeks may well be the part of Illinois where these two broods overlap. This co-emergence of 13-year and 17-year broods hasn’t happened since 1803, early in Thomas Jefferson’s presidency. It’s kind of a big deal.
Why Do Periodical Cicadas Emerge All At Once?
These red-eyed insects have such a strange lifecycle, but it serves a purpose. The mass emergence ensures the survival of the species. Predators absolutely love cicadas – they are high in protein and nutrients. Even some humans find them to be quite tasty. Because there are so many cicadas at one time, it’s a sure bet that some cicadas will survive to reproduce. Here’s the cycle of a cicada’s life.
Egg Stage
Adult cicadas lay their eggs in slits that they cut into tree branches or stems with their ovipositors. Each female can lay hundreds of eggs, usually in multiple locations on trees or woody perennials with branches smaller than a pencil. After 6 to 10 weeks, these eggs hatch.
Nymph Stage
After the eggs hatch, the tiny nymphs drop to the ground and burrow into the soil, creating underground chambers where they feed on tree sap from roots. This underground stage is the longest period of the cicadas’ life cycle – 13 or 17 years for periodical cicadas, or 2 to 5 years for annual cicadas.
Emergence (Spring & Summer 2024)
When it’s time to become adults, the nymphs tunnel to the surface. They shed their exoskeletons (or carapaces) in a process called molting. Many of us are starting to see these leftover shells of cicada nymphs all over the ground. Don’t worry, these exoskeletons aren’t doing any harm, despite the mess.
Adult Stage
Newly molted adults are called tenerals. They have soft bodies and are pale at first, but harden and darken within hours. This stage is very short – only about 4 to 6 weeks. It’s also where all the fun happens.
Mating & Death
The intense noise we hear during the day is adult males, calling to females to try to attract a mate. In fact, each species has a distinct song. After mating, the females begin to lay eggs and the cycle is complete. The genes are passed on to another generation, and the adults typically die soon after.
Do I Need to Protect My Plants from Cicadas?
Most vegetables, herbs, and flowers are relatively safe from cicadas, who are more interested in mating than anything else right now. However, if you plan to plant any woody perennials, shrubs, or saplings this year, you might want to delay to minimize damage and prevent those plants from becoming hosts for the eggs. If you already have woody plants or young trees, protect them from egg-laying adult females once you start hearing the love ballads of the males. This is easy to do with netting and other barriers that can be taken down after the peak of cicada mating season.
Soil Benefits of Cicadas
Despite the noise and inconvenience, cicadas can actually be quite good for your garden in the long term! As nymphs emerge from underground, they can improve soil quality by aerating it. You can take advantage of this by planting fast-growing annuals after the main emergence wave has passed. That way, those plants will immediately benefit from the improved soil conditions. After the cicadas decline, they will die and begin to decompose, enriching the soil. Plant cover crops like buckwheat or oats to stabilize the soil and incorporate the nutrients left behind.
Ecosystem Impacts of Cicadas
Cicadas use mass emergence as their primary defense against predators. They don’t use camouflage, and they certainly aren’t stealthy. As they scream out their mating calls, birds hear an invitation to a delicious All-You-Can-Eat Cicada Buffet. This means that while cicadas are active, other species won’t be as attractive to their predators, so they can focus on their own life cycles. This is good news for monarch butterflies, who could use the reprieve. Let’s hope it leads to at least a modest population boost this year. If you’re growing milkweed, don’t be sad if these Very Hungry Caterpillars visit. Instead, be glad that your flowers are providing a home and a nourishing meal for monarch butterflies. However, common garden pests like hornworms and cabbage loopers may also flourish, so be on the lookout. You may have to be extra vigilant this year.
Don't freak out about the Great Cicada Emergence of 2024 – I promise, it will be over before you know it, and your garden will be just fine! In fact, you can take advantage of some of the benefits to your soil with a little bit of planning. Even if you’re not typically a bug person, try to enjoy this once-in-a-lifetime event and learn more about the wonders of the natural world. Make sure to take some pictures and recordings to share with future generations. If you’re especially brave, you could even try out some cicada recipes! Whatever you do, embrace the experience and make the most of this unique natural event.
