Cicadas are insects known for their periodic appearances, which leave distinctive signs in the landscape. This article describes the appearance of cicada emergence holes, providing clarity for those observing these ground disturbances.
Key Characteristics of Cicada Emergence Holes
Cicada emergence holes are circular openings in the ground, typically 1/2 to 1 inch in diameter. They are often found in lawns, gardens, wooded areas, particularly near trees, and occasionally in cracks in pavement. Many of these holes feature a “chimney” or “turret,” which is a cylindrical tube made of mud or soil extending upwards from the hole.
These mud chimneys can vary in height, from a simple golf-ball sized dome to structures over six inches tall, and are often formed when the soil is wet or muddy. The presence of these structures indicates cicada activity, though some emergence holes might appear as simple open holes without a chimney, especially in drier conditions. These holes can appear in significant numbers, sometimes hundreds per square meter, indicating a large-scale emergence. The soil around these fresh emergence sites may also appear moist or recently disturbed.
Distinguishing Cicada Holes from Other Ground Openings
Distinguishing cicada holes from other ground disturbances is important. Unlike earthworm castings, cicada holes are defined, open tunnels. Ant hills have a central, tiny opening surrounded by fine, loose soil.
Other insects, such as ground bees or cicada killer wasps, also create ground holes, but their burrows lack the distinct mud chimney characteristic of cicadas. Cicada killer wasp holes can be up to 1 inch in diameter with a loose mound of dirt, but they prefer dry, sandy soil and do not construct mud turrets. Small animal burrows, created by rodents or other creatures, are often larger than cicada holes and might have claw marks or displaced sod. The mud chimney or 1/2 to 1-inch diameter helps identify cicada emergence sites.
The Purpose and Significance of Cicada Holes
Cicada emergence holes serve as exit tunnels for cicada nymphs, marking the culmination of their long underground development. After years spent feeding on tree roots beneath the soil, these nymphs construct these tunnels to reach the surface, where they will undergo their final molt into winged adults. The construction of mud chimneys in wet conditions helps prevent the tunnels from collapsing or flooding, ensuring a clear path for emergence.
Observing these holes indicates that a cicada emergence is imminent or already underway, signaling the end of their subterranean phase. These holes are generally harmless to lawns and gardens; the tunneling activity can even aerate the soil, which benefits root growth. These structures are a natural part of the cicada life cycle and do not typically require intervention.