Cicadas are known for the buzzing chorus that fills the air during their emergence. They appear in large, synchronized numbers after long periods underground, prompting questions about their next appearance.
The Next Major Emergence
Following the significant dual emergence of Brood XIII and Brood XIX in 2024, the next major periodical cicada event will occur in 2025. Brood XIV, a 17-year cicada brood, is anticipated to emerge in late April and early May of 2025.
States expected to witness the emergence of Brood XIV include Georgia, Kentucky, Indiana, Massachusetts, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. While parts of Kentucky and Tennessee may experience the densest populations, other listed states will see smaller numbers. The precise timing of their appearance depends on local soil temperatures, with emergence typically triggered when the ground 8 inches deep reaches 64 degrees Fahrenheit.
The Science Behind Periodical Cicadas
Periodical cicadas (Magicicada) are known for their long, synchronized life cycles of either 13 or 17 years. These prime number cycles potentially help them avoid predators whose populations might fluctuate on shorter cycles. Unlike annual cicadas, which have a 2-5 year life cycle and appear every summer, periodical cicadas emerge all at once after long subterranean development.
A “brood” refers to a geographically distinct population of periodical cicadas that emerge in the same year on a predictable schedule. There are 12 known broods of 17-year cicadas and three broods of 13-year cicadas in the eastern United States, each designated with a Roman numeral. After hatching from eggs laid in tree branches, the tiny nymphs drop to the ground, burrowing underground to feed on xylem fluids from tree roots for the vast majority of their lives.
What Happens When Cicadas Emerge
When periodical cicadas emerge, they can reach millions per acre. They typically appear between late April and early June, shedding their nymphal exoskeletons on trees and other vertical surfaces. Male cicadas create a loud buzzing sound, aggregating in “chorus centers” to attract mates. This sound can be intense, reaching noise levels between 90 and 100 decibels.
Despite their loud noise, cicadas are harmless to humans and pets; they do not bite or sting. They are also not destructive pests to most established trees, as they primarily feed on tree root fluids and do not chew leaves or crops like locusts. Young trees, however, can be vulnerable to damage when female cicadas lay their eggs in small branches, but this can be mitigated with netting. Adult cicadas live for only about four to six weeks above ground, mating and laying eggs before they die, and their bodies contribute nutrients to the soil.