🦗 Cicadas — Annual & Periodical Species Overview

Magicicada spp. (periodical) · Neotibicen spp. (annual) · Hemiptera: Cicadidae

Cicadas are among the most visible and audible insects of North American summers and the source of more anxious homeowner calls than almost any other non-pest species. In nearly all cases, the right response is no response — but knowing the difference between annual and periodical cicadas helps you anticipate what will happen and protect young trees during a brood emergence.

CicadaHemipteraPeriodicalAnnualBroodTree Health
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Risk Level
Very Low (Mostly Harmless)
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PestControlBasics Editorial Team
Reviewed by Derek Giordano · Updated 2026

🔍 Identification

Adult cicadas are 1 to 2 inches long with a stout body, large compound eyes set wide apart on the head, transparent wings held tent-like over the body when at rest, and a characteristic dome-shaped thorax. They are easy to identify as cicadas; the question is which kind.

Annual cicadas (Neotibicen and related genera, often called dog-day cicadas) emerge every summer in most of the eastern and central US. They are larger (1.5-2 inches), greenish or brownish with darker markings, and have black eyes. Each individual lives underground as a nymph for 2 to 5 years, but because broods overlap, adults appear every year. These are the cicadas responsible for the steady late-summer afternoon chorus across most of the country.

Periodical cicadas (Magicicada, seven species across 13- and 17-year life cycles) emerge in synchronized broods at a single location every 13 or 17 years. They are smaller (1-1.5 inches), with a striking black body, bright orange-red eyes, and orange wing veins. Numbered broods (Brood X, Brood XIX, etc.) are mapped to specific geographies and years, and a periodical emergence in your area is a roughly once-or-twice-in-a-lifetime event. The trillions of emerging adults, the volume of their chorus, and the duration of the emergence (4-6 weeks) make these emergences genuinely overwhelming experiences, but the population effects on most landscapes are short-lived.

🧬 Biology & Behavior

All cicadas spend the great majority of their lives as underground nymphs feeding on xylem fluid from tree roots. When mature, they tunnel to the surface, emerge at night, climb a vertical surface (trunk, post, fence), shed their exoskeleton, and emerge as winged adults. The shed exoskeletons (exuviae) that appear by the hundreds or thousands on tree trunks during emergence are harmless and biodegradable within weeks.

Adult cicadas live only 2-6 weeks. Their adult life is devoted entirely to mating, which is announced by the male's species-specific call produced by tymbals on the abdomen — among the loudest sounds produced by any insect, reaching 100+ decibels at close range. After mating, females cut slits into the bark of small-diameter (pencil to thumb-thick) tree branches and lay eggs inside. The eggs hatch in 6-10 weeks; the tiny first-instar nymphs drop to the ground and burrow into the soil to begin their multi-year underground life.

Cicadas do not bite, sting, or transmit disease. They cannot harm humans, pets, livestock, or structures. Their mouthparts are adapted exclusively for piercing plant tissue to feed on xylem fluid. The most aggressive thing an adult cicada will do is fly clumsily into a person — they are weak fliers, easily startled, and frequently land on humans by accident.

⚠️ Damage

The only real damage cicadas cause is to small-diameter branches on young trees during female egg-laying, a process called flagging. After females insert eggs into branches roughly 1/4 to 1/2 inch in diameter, those branches often wilt and break at the egg-laying slit, producing the characteristic brown wilted ends (flags) visible across an oak or maple in mid-summer following a periodical emergence. This damage is cosmetic on mature trees, which can lose dozens of small branch tips with no measurable effect on overall tree health. It is more consequential on young or newly planted trees, where the loss of a significant fraction of leaders can shape growth for years and, in extreme cases, kill a recently planted sapling.

Annual cicadas cause flagging too, but in much lower numbers — typically a few branch tips per tree per year, often unnoticed. Periodical brood emergences produce flagging on a scale that can be visually dramatic for several months, especially in oak, maple, dogwood, hickory, and fruit-tree species, but established trees recover fully and many species actually benefit in the longer term from the natural pruning effect.

Cicadas do not damage lawns, vegetable gardens, ornamentals, vines, or non-woody plants. Their feeding on root xylem is too dilute to register at the per-tree level.

🔧 Treatment — Almost Always Unnecessary

Annual emergences: No treatment needed or recommended. The chorus is loud for a few weeks of late summer, individual cicadas occasionally fly into windows or land on people, and small numbers of flagged branch tips appear on trees. None of this warrants chemical intervention, and broadcast insecticide application during cicada emergence is both ineffective (the population is too large and the adult life is too short) and harmful to non-target species including pollinators.

Periodical emergences: Protect newly planted young trees with fine mesh netting (cheesecloth or 1/4-inch insect mesh works) tied at the trunk for the 4-6 week emergence period. This is the single most evidence-supported intervention and the only one consistently recommended by university extension services. Spraying mature trees is not effective at the scale of a brood emergence; trillions of cicadas saturate the area, and reapplication intervals cannot keep up. Allow established trees to absorb the natural pruning effect.

Removal of dead cicadas: After the emergence, large numbers of dead cicadas accumulate at the base of trees and along fence lines. This is a temporary smell and aesthetic concern, not a pest problem. They decompose within a few weeks and contribute meaningfully to soil nitrogen; sweeping them into a garden bed or compost is the most useful disposition.

👷 When to Call a Pro

Almost never for the cicadas themselves. The only situation that genuinely warrants an arborist's attention is a young tree (less than 4-5 years old) showing extensive flagging during a periodical emergence in an orchard or nursery setting where economic loss is at stake — and even there, the standard recommendation is mesh netting rather than spraying. If you have a confirmed periodical brood emergence in your area and you've planted young trees within the last two years, an arborist consultation in spring before emergence is more useful than any reactive intervention.

If something that looks like a cicada is biting, stinging, or damaging structures, it isn't a cicada — common misidentifications include cicada killer wasps (which look superficially like large wasps and dig nests in lawns), carpenter bees, and certain large hover flies. An identification check before any treatment is essential.

❓ FAQ

Are cicadas dangerous to humans, pets, or livestock?
No. Cicadas don't bite, sting, transmit disease, or produce defensive toxins. Their mouthparts are designed exclusively for piercing plant tissue to feed on xylem fluid. Dogs and cats sometimes eat them in large numbers during emergences, which can cause temporary digestive upset (the exoskeleton is hard to digest) but isn't dangerous beyond that. The most common pet issue during a major periodical emergence is choking on a swallowed cicada, which is easily prevented by limiting outdoor unsupervised time during peak emergence. Livestock occasionally show similar mild gastrointestinal reactions but no clinically significant harm has been documented.
When are periodical cicadas coming back to my area?
Periodical cicada broods are mapped to specific geographies and years. Brood X (17-year cycle) emerged in 2021 across the eastern US and is next due in 2038. Brood XIII (17-year) and Brood XIX (13-year) had a rare overlapping emergence in 2024 across the Midwest, the first such co-emergence since 1803. Smaller broods emerge nearly every year somewhere in the eastern US. The USDA and university extension services publish brood maps showing exactly when and where to expect the next emergence in your county; the University of Connecticut maintains the most current consolidated map.
Will cicadas kill my trees?
Established trees, no — even during a heavy periodical emergence, the egg-laying flagging causes cosmetic damage but doesn't measurably affect overall tree health. Most arborists actually consider the natural pruning effect mildly beneficial in the long term. Young trees planted within the last 2-3 years are genuinely vulnerable to a periodical emergence because the loss of a high percentage of branch tips can stunt growth or kill a young leader. Protect young trees with fine mesh netting tied at the trunk during emergence; this is more effective than any chemical treatment and is the standard university extension recommendation.
Why are cicadas so loud?
Male cicadas produce sound using paired tymbals on the abdomen — membranes that buckle and unbuckle to produce sound pulses, amplified by a hollow abdominal cavity. The result is among the loudest insect sounds in nature, reaching 100+ decibels at close range — comparable to a chainsaw at three feet. Each species produces a distinctive call, which is how females identify and select males of their own species. During a periodical brood emergence, the combined chorus of millions of males can reach noise levels uncomfortable for extended exposure and is sometimes mistaken at a distance for power tools, alarms, or sirens.
Should I spray my yard before a periodical emergence?
No. Pre-emergence soil spraying is not recommended by any university extension service. The nymphs are too deep, the population too large, and the adult life too short for the cost-benefit math to work. Worse, broadcast insecticide application kills beneficial soil organisms and pollinators with no measurable effect on the cicada emergence. The evidence-supported intervention is mesh netting on young trees during the emergence — protective rather than chemical — and tolerance of the temporary noise and visual presence for everything else.
What should I do with all the dead cicadas after the emergence?
Nothing — or, more usefully, rake them into garden beds or compost. Dead cicadas decompose rapidly and release a significant pulse of nitrogen back into the soil; ecologists have measured measurable boosts to plant growth in the year following a major periodical emergence. The smell during peak die-off can be unpleasant but resolves within 7-14 days. There's no public-health reason to remove them from the property, and bagging-and-trashing them wastes a useful soil amendment.
DG
Derek Giordano
Certified Pest Control Operator · Former Business Owner
Derek ran his own pest control company in Florida for several years, servicing thousands of regular customers. All content is based on hands-on field experience and current EPA & university extension guidelines.
📚 Sources: USDA Cicada Information · University of Connecticut — Periodical Cicada · Penn State Extension — Cicadas
Published: May 13, 2026 · Updated: May 13, 2026

Cicada killer wasps: the most common misidentification

Each summer, university extension offices field a heavy volume of calls about large yellow-and-black insects digging holes in lawns, behaving territorially around them, and described by callers as 'cicadas the size of a hummingbird.' These are not cicadas. They are Sphecius speciosus, the eastern cicada killer wasp — solitary ground-nesting wasps that hunt adult cicadas as food for their larvae. The visual confusion is understandable because cicada killers are among the largest wasps in North America (up to 2 inches long), but the differences are unmistakable once you know what to look for: cicada killers have the classic wasp narrow waist, smooth body, and rapid flight; they patrol or hover around nest entrances in lawns rather than calling from trees; and they make characteristic conical mounds of fine soil around their burrow entrances. The behavior is also different in a way that matters: cicada killers appear aggressive because males hover at face level and patrol nest sites, but male cicada killers cannot sting (the stinger is a modified ovipositor and only females have it), and females sting only when physically pinched or stepped on. They are docile by stinging-insect standards. Treatment of cicada killers in residential lawns is widely overdone; the natural population dies off each fall, the burrows do not significantly damage turf, and the population is self-limiting because each female provisions only a few burrows per season. Where a treatment is truly necessary — high-traffic areas, schools, allergy concerns — applying pyrethroid dust directly to nest entrances at dusk is more effective than broadcast spraying.

Reading a brood map: what 'Brood XIV in 2025' actually means

The periodical cicada literature uses Roman numeral brood designations that confuse first-time readers, but the system is logical once decoded. Each brood is a single geographic and temporal population that emerges in lockstep every 13 or 17 years. Broods I through XVII are 17-year cycles; Broods XVIII through XXX are 13-year cycles (most no longer exist or have very limited range). Brood numbers don't reflect size or species — they're historical labels assigned by entomologist Charles Lester Marlatt in the early 1900s based on emergence years. Brood X is the largest 17-year brood, covering parts of 15 eastern states and emerging in 1987, 2004, 2021, and next in 2038. Brood XIX is the largest 13-year brood, last emerged in 2024, next in 2037. The 2024 emergence was notable because Brood XIII (17-year, northern Illinois region) overlapped geographically with Brood XIX (13-year, broader Midwest and South), a coincidence that recurs every 221 years. Practically, knowing your local brood means knowing exactly when to expect the next emergence and which years to defer planting expensive young trees. The University of Connecticut maintains the most accessible brood map online, and most state extension services publish localized predictions in the months leading up to an emergence.

Why broadcast spraying during emergence does more harm than good

Homeowner instinct during a heavy cicada emergence is to spray something — the yard, the trees, the perimeter — to reduce the visible insect load. The math behind why this fails is straightforward but worth understanding because it generalizes to other situations. A heavy periodical emergence produces 1-1.5 million cicadas per acre in peak areas, all emerging within a 7-10 day window. Even a highly effective contact insecticide killing 95% of adults at application would still leave 50,000-75,000 cicadas per acre, plus continued emergence over the following days. Reapplication intervals for residential pyrethroids are typically 2-4 weeks, and the active adult population turns over in roughly 4-6 weeks — meaning at most you'd get one or two applications across the emergence, with no possible reduction below the threshold where the chorus and physical presence become acceptable. The collateral damage is meanwhile substantial: broadcast pyrethroids kill bees, butterflies, beneficial parasitoids, and ground beetles, with effects that persist long after the cicadas are gone. The asymmetric outcome — meaningful damage to beneficial species, negligible reduction in cicada numbers — is why no university extension service recommends spraying during emergence and why responsible pest control operators decline cicada treatment calls. The right answer remains targeted mesh netting on young trees and tolerance of the temporary noise and visual presence on everything else.