There is a new, unusual noise you might hear when you walk outside these days. This is the song of the periodical cicadas, and 2024 is North Carolina’s year to have more cicadas than usual to provide extra “music” to herald in our summertime. It’s also hard to miss all the insect skins covering almost every vertical surface these days, like light poles, mailboxes, fences, shrubs and trees, and more! Today we will talk about these alien yet beautiful creatures that visit our area once every 13 or 17 years (how odd, right?), how they differ from our annual cicadas we see each year, and whether you need to be concerned and prepare your yards for their arrival.
2024 Periodical Cicadas - The Emergence of the Centuries
To truly marvel in the moment we are currently in, let’s first define what cicadas are. Cicadas are insects native to North America that are relatives of stink bugs, plant bugs, and other insects which feed on the fluids of plants. Most of their lives occur underground, where as juveniles (also called nymphs) they feed on the sap of plant roots. They remain in the ground for one to 17 years, depending on the species. In their final year, once the ground is warm enough in the spring, nymphs will emerge and find a location to complete their final molt or shed their skin to become an adult cicada. Male cicadas will call to females of the same species with a unique song using an organ called a tymbal, which has ribs like a bendy straw and creates a drone when vibrated at high speed. Once mated, female cicadas use their drill-like ovipositors to saw into the stems of various woody plants and trees to lay their eggs. After a few weeks, the adult cicadas die and nymphs hatch from the eggs to drop to the soil and burrow into the ground beside roots to feed and wait until it’s their time to emerge years later.
Periodical cicadas are special species of cicadas found only in the eastern United States and nowhere else in the world! They emerge earlier than annual or “dog-day cicadas,” typically between May to June (while annual cicadas appear later, between July to August), and also have much longer life cycles, either 13- or 17-years compared to annual cicadas which live two years. They also look quite different, with periodical cicadas being smaller in size with black bodies, red eyes, and orange wings compared to the green-black colors we see with annual cicadas. They also have a different call, which I think sounds similar to a siren! There are six periodical cicada broods which emerge in NC (II, VI, IX, X, XIV, and XIX), and they all emerge during different years.
2024 is an especially exciting year for us periodical cicada enthusiasts, as we have two broods emerging in the US this year; Brood XIII (13), which has a 17-year life cycle, and Brood XIX (19), which has a 13-year life cycle. We will only see Brood XIX here in NC, and the next time they will emerge for us to see will be 2037. However, because these two broods are prime numbers and these rarely line up, they haven’t emerged together since 1803, more than 200 years ago!
Should we take action to protect plants during the periodical cicada emergence?
While the numbers of cicadas appearing in our yards at this moment can seem alarming, these insects are not a significant threat to us, our pets, and typically not our plants. While cicada nymphs feed on the roots of plants, it takes large numbers of them to cause significant damage. Young trees and woody plants are at the highest risk of damage from adult female cicadas, who create slits in their stems to lay eggs. Normally we do not see an impact on these plants from annual cicadas, but during years like this one when large periodical broods emerge, these numbers have the potential to weaken or kill young trees or woody plants. It is best not to plant young trees within 2-3 years of an anticipated periodical cicada brood emergence. Existing young trees and woody plants can be protected by using netting with 1/4 inch or finer mesh when cicadas are active, which is typically only a few weeks.
For more information on cicadas, contact North Carolina Cooperative Extension at the Lee County Center and ask for Meredith Favre, our Local Foods Coordinator, for more information.
