Cicadas make holes in the ground as a part of their life cycle. These openings are exit tunnels created by cicada nymphs when they emerge from their underground dormancy to transform into winged adults. These holes indicate cicada activity.
The Underground Journey and Emergence
Cicadas spend most of their lives beneath the soil as nymphs. After hatching from eggs laid in tree branches, tiny nymphs drop to the ground and burrow into the soil, where they feed on sap from tree roots. This underground phase lasts two to seventeen years, depending on the species. Periodical cicadas emerge synchronously after 13 or 17 years.
During their underground life, cicada nymphs tunnel through the soil, growing and molting as they feed. When emergence approaches, triggered by specific soil temperatures—around 64 to 65 degrees Fahrenheit at a depth of 8 to 18 inches—the nymphs dig upward toward the surface. This upward tunneling creates the exit holes visible in the ground. They often create these tunnels preemptively, waiting below the surface until conditions are optimal for ascent.
What Cicada Emergence Holes Look Like
Cicada emergence holes are circular and small, dime-sized to one inch in diameter. They are found in areas with trees, but can also appear in grassy areas.
When soil is wet or muddy, cicada nymphs construct “chimneys” or “turrets” above their emergence holes. These mud structures vary in size, from small domes to over six inches tall. Chimneys prevent water and mud from back-filling tunnels, ensuring a clear path for emergence. Their appearance indicates cicada emergence is imminent.
Are These Holes a Concern?
The holes created by emerging cicadas are not a cause for concern for lawns or plants. While there can be many holes, hundreds per square meter, they are temporary and do not cause long-term damage. The tunneling activity provides a natural aeration benefit to the soil, improving water infiltration and promoting root growth.
Cicadas do not eat grass, vegetables, or flowers. Their diet as nymphs consists of tree root sap, and adult cicadas consume sap from trees and shrubs. Minor plant damage from adult cicadas relates to egg-laying in young tree branches, not their ground holes. After emergence, their decaying bodies add nutrients to the soil.
Distinguishing Cicada Holes from Other Ground Openings
Cicada emergence holes can be differentiated from other ground openings in a yard. Cicada holes are uniform, dime-sized to one inch in diameter, and appear in clusters. Unlike holes made by burrowing animals, cicada holes lack excavated soil piles around them, as nymphs pack soil behind them as they ascend.
Mud chimneys or turrets are an identifying feature of cicada emergence when soil is moist. These are distinct from the smaller, irregular holes of earthworms, leaving castings, or larger excavations of mammals like moles or voles. Their appearance in spring or early summer, when soil temperatures are suitable, also helps identify cicada holes.