The Year of the Cicada: Will It Live Up to the Hype?
The state of Illinois is set to experience a natural phenomenon that hasn’t happened since 1803. It’s the simultaneous emergence of two distinct broods of cicadas. It’s been all over the news but, will it live up to the hype? And, what do you really need to know about these periodical cicadas?
Should you be worried? The answer is maybe but also maybe not. It all depends on where you live. Here’s what you need to know about these periodical cicadas and what to expect when they emerge.
What Makes 2024 a Significant Year for Periodical Cicadas?
This year, two large broods of periodical cicadas will be emerging throughout Illinois at the same time. This is a rare occurrence that only happens every 221 years. Brood XIX, also know as the Great Southern Brood, is a 13-year periodical cicada found in the southern half of Illinois. Brood XIII, also known as the Northern Illinois Brood, is a 17-year periodical cicada found in the northern half of Illinois.
Brood XXIII, also known as the Mississippi Valley Brood, is a 2028 group that could emerge in 2024 in parts of southern Illinois, called stragglers.
According to the University of Illinois Extension, a few places in central Illinois near Springfield are where the broods will converge, but the majority of the state will only notice one brood in their area.
NEWer Construction will most likely have fewer cicadas
In addition, newer subdivisions that have been developed in the last 20-30 years may not see as high of cicada populations as those in older neighborhoods with mature trees or homes near long-established forested areas. Most new construction has taken place on farmland where few trees existed, and the practice of scraping the soil off to set grades in new developments would cause very few cicadas to survive.
Cicadas do not migrate quickly. They are weak fliers, traveling no more than 1/2 mile in a lifetime.
What Do Periodical Cicadas feed On?
Periodical cicadas spend the majority of their lives in the soil feeding off the sap of tree roots in the nymph phase of their lifecycle. Despite their large numbers, they do not harm the trees they feed on as nymphs.¹
Nymphs emerge in May to early June when the soil temperature reaches 64 degrees several inches below the surface.
Dr. Fredric Miller, Illinois Forest Health Specialist and senior research scientist for The Morton Arboretum says, “adult cicadas briefly feed on a variety of woody plants,” but adds, “feeding damage from the adults is minimal at most.”
HOW DO PERIODICAL CICADAS CAUSE DAMAGE?
Females lay their eggs in the new growth of woody plants, typically in branches 1/8to 7/16 inch in diameter.² These linear cuts produce splintering and cause breakage of small branches, also known as flagging. This results in minor damage to mature trees and shrubs that equate to natural pruning. However, this can have a more significant effect on young trees and shrubs planted in areas with higher populations of periodical cicadas.
WHAT CAN I DO TO MITIGATE DAMAGE TO YOUNG WOODY PLANTS?
The good news is this event is very short lived.A month after emerging, the adult cicadas die.However, there are some best practices homeowners can use to to prevent damage to young vulnerable trees and shrubs:
- If you live in an area with a higher concentration of periodical cicadas, avoid planting very young trees that are less than two inches in diameter until mating has ceased.
- If you have a number of susceptible plants, you can cover them with fine netting and remove it once the emergence event is over.
- Chemical applications are not advised as studies have shown to be ineffective and can be harmful to beneficial insects.
Watch how to properly cover a young tree
Annual cicadas, also known as Dog Day cicadas, emerge July through August and typically have a lifecycle of 2-5 years. Their shorter lifespan creates overlaps of brood emergences on a yearly basis and therefore not as significant of an event as the periodical cicada.
KEY TAKEAWAYS
While 2024 is a significant year for periodical cicadas in Illinois, we know that only a few areas will see more than one brood in the southern half of the state. Damage to plants is restricted to woody branches smaller than 1/2 inch in diameter, which poses no risk to healthy, mature trees and shrubs. You can wait to plant young trees and shrubs, however, only older neighborhoods or areas adjacent to long-established forested areas will see higher concentrations of these periodical cicadas. If you are concerned about your young woody plants, properly covering them with fine mesh is a simple solution that can be utilized during their brief mating period.
¹ Speer, J.H., K. Clay, G. Bishop, and M. Creech. 2010. The effect of periodical cicadas on growth of five tree species in Midwestern deciduous forests. The American Midland Naturalist, 164(2); 173-186.
² Miller, F. and W. Crowley. 1998. Effects of periodical cicada (hom*optera: Cicadidae: Magicicada septendecim and Magicicada cassini) ovipostitional injury on woody plants. J. of Arboriculture 24(5): 248-253.
Bugging Out: Cicadas, Garden Pests & More
Saturday, April 13 // 10:30am – 2pm // Aurora
Explore the fascinating world of Bugs, Insects, and Creepy Crawlies! Learn how these tiny creatures play a huge role in our ecosystem. Whether you’re a bug enthusiast or prefer to keep them at a distance, learn something new at The Growing Place!All talks and activities are free. Learn more!
