Signs of 17-Year Periodical Cicada Infestation in Urban Areas

Periodical cicadas are among the most fascinating and unique insects found in North America. Known for their remarkable 17-year life cycle, these insects emerge en masse after spending nearly two decades underground as nymphs. When they do appear, their sheer numbers and distinctive behaviors can significantly impact both natural and urban environments. Recognizing the signs of a 17-year periodical cicada infestation, especially in urban areas, is essential for homeowners, city planners, and gardeners alike to manage their presence effectively.

In this article, we explore the key indicators of a periodical cicada infestation, explain their life cycle, discuss their impact on urban landscapes, and offer practical advice for dealing with these extraordinary insects.

Understanding the 17-Year Periodical Cicada

Before diving into the signs of infestation, it’s important to understand what makes 17-year periodical cicadas unique.

Life Cycle Overview

Periodical cicadas (genus Magicicada) are known for their synchronized emergence every 13 or 17 years. The 17-year cicadas spend most of their lives underground feeding on sap from tree roots. After completing this extended development phase, they emerge simultaneously in large numbers during late spring to early summer.

Once above ground, adult cicadas live only about four to six weeks. During this time, males sing loudly to attract females. After mating, females lay eggs in tree branches. Shortly thereafter, adults die off, and the newly hatched nymphs burrow into the soil to begin the long underground stage anew.

Why Their Emergence Is Noteworthy

The simultaneous emergence of millions of cicadas is a natural survival strategy called “predator satiation.” By overwhelming predators with sheer numbers, enough cicadas survive to reproduce. However, this mass appearance can cause noticeable disruptions in urban areas where people aren’t used to such insect swarms.

Key Signs of a 17-Year Periodical Cicada Infestation in Urban Areas

Urban environments often have a mix of trees, shrubs, lawns, and human activity that can both attract and be affected by periodical cicadas. Here are several clear signs indicating an infestation:

1. Loud and Continuous Singing Noise

One of the earliest and most obvious signs is the loud buzzing or singing made by male cicadas. Their song is a distinctive high-pitched trill or buzzing sound that can reach up to 100 decibels, comparable to a motorcycle or lawnmower.

In urban parks, backyards, or tree-lined streets, residents may notice these noises starting at dawn and continuing throughout much of the day during peak emergence. If you hear this constant chorus after nearly two decades without cicadas in your area, chances are a periodical cicada emergence is underway.

2. Appearance of Adult Cicadas on Trees and Structures

Once they emerge from underground nymphal chambers (exit holes), adult cicadas typically climb nearby vertical surfaces such as tree trunks, fences, walls, or poles to molt into their winged adult form.

In urban settings, you might notice:

• Empty exoskeleton shells clinging to bark or wooden surfaces.
• Clusters of live adult cicadas resting on trees or sometimes on buildings.
• Cicadas flying clumsily around streetlights or porch lights at dusk.

The sudden presence of dozens or hundreds of these large insects (about 1 to 1.5 inches long) is a strong sign of infestation.

3. Countless Cicada Exit Holes in Soil Around Trees

Before emerging as adults, the nymphs dig through soil to break free from underground tunnels. These exit holes are small (approximately 0.5 inches wide) round openings typically found near the base of trees or shrubs.

In urban yards or parks with mature trees, a noticeable increase in these small holes clustered around root zones indicates recent emergence activity beneath the surface.

4. Damage to Tree Branches and Twigs from Egg-Laying

Female periodical cicadas use a sharp ovipositor to cut slits into small branches and twigs where they deposit eggs. This process often causes visible damage characterized by:

• Tiny slits or cuts along young branches.
• Dead branch tips sometimes called “flagging” because affected ends turn brown and wilt.
• Broken or weakened twigs prone to breaking off during windy conditions.

While mature trees usually recover from this damage without serious harm, younger or ornamental trees commonly found in urban landscapes may suffer stunted growth or unsightly damage during heavy infestations.

5. Mass Dead Cicada Bodies Accumulating on Ground Surfaces

Following mating and egg-laying activities lasting only a few weeks, adult cicadas die en masse. Large numbers of dead bodies often accumulate beneath trees where they congregated during their brief adult stage.

In cities and suburban neighborhoods with limited space for natural decomposition, dead cicadas may pile up noticeably on sidewalks, patios, lawns, parked cars, or streets, sometimes causing nuisance odors when left unattended.

6. Increased Activity by Predators Feeding on Cicadas

Many animals take advantage of the sudden abundance of food during periodical cicada emergences including:

• Birds such as crows, blue jays, robins.
• Small mammals like squirrels and raccoons.
• Insects including wasps and ants.

In urban areas near green spaces or wooded patches, unusual predatory behavior may be observed, such as birds flocking intensely around infested trees or increased presence of scavenging insects near dead bodies.

Impact of Periodical Cicada Infestations in Urban Areas

Although periodical cicadas do not bite humans or cause direct harm beyond minor plant damage, their emergence can have several impacts on urban communities:

Landscape Aesthetics

The egg-laying damage can mar ornamental plants and young trees commonly planted along streets and gardens. Branch flagging reduces visual appeal and can stress delicate species.

Public Nuisance

The loud noise levels can be disruptive for residents especially those unaccustomed to insect choruses lasting several weeks.

Fallen dead bodies create cleanup challenges for homeowners and municipal services tasked with maintaining parks and public spaces.

Potential Stress on Trees

Repeated heavy infestations over consecutive emergences may weaken young urban trees reducing their vigor over time although mature healthy trees usually tolerate cicada activity well.

Managing Periodical Cicada Infestations in Urban Settings

Complete prevention isn’t possible due to the predictable nature of their life cycle combined with mass emergences over vast geographic ranges; however some measures help mitigate negative effects:

Monitoring Emergence Timing

Knowing when local broods are predicted helps residents prepare ahead of time, usually outbreaks occur between late May through June depending on region.

Protecting Young Trees With Netting

Covering vulnerable saplings with fine mesh netting before emergence prevents females from laying eggs on branches reducing damage severity.

Pruning Damaged Branches Post-Emergence

Removing flagged twigs after adults die encourages healthier new growth during subsequent seasons.

Cleanup Dead Bodies Promptly

Raking up carcasses reduces odor issues and deters scavenger pests from congregating excessively in residential areas.

Educational Outreach

Informing community members about the harmless nature yet temporary inconvenience caused by these insects encourages tolerance rather than unnecessary pesticide use which harms beneficial wildlife.

Conclusion

The unmistakable signs of a 17-year periodical cicada infestation in urban areas include loud continuous singing noises from male adults; visible clusters of adults and empty exoskeletons on trees; numerous exit holes near tree bases; branch damage caused by egg-laying females; accumulation of dead bodies; and increased predator activity feeding on them.

Understanding these signs allows residents and city officials to respond effectively by protecting vulnerable plants while minimizing human discomfort during what is ultimately a brief but spectacular natural event. While disruptive temporarily, these emergences represent important ecological phenomena that contribute greatly to forest health over long timescales, a reminder that even within our cities nature continues its intricate cycles with drama largely unseen until now.