Most homeowners meet the cicada killer through its nest rather than the wasp itself. Sometime in mid-July, quarter-sized holes appear across a thin patch of lawn, each with a fan of loose soil beside it, and something very large starts flying low over the grass. It reads like an infestation. It isn’t one.
For non-aggressive wasps I've had great luck spraying nests with this Spectracide wasp remover in the evening. For a nest up high in an eave, soffit, or tree, this Gotcha pole adapter clamps onto the can so you can spray from the end of an extension pole and treat the nest from 10+ feet away instead of standing right under it. And for anything aggressive I wear this ridiculous-looking upper torso beekeeping suit and keep my distance. It seems silly, but trust me, I learned the hard way.
A cicada killer nest is the work of a single female raising her own young, with no colony behind her and nothing to defend. A lawn with forty holes in it has forty independent wasps, not one nest with forty workers — and that distinction is the difference between a curiosity and a genuine hazard. This guide covers what the burrow actually looks like, how to separate it from the ground nests that are dangerous, what’s happening in the tunnel underneath, and what (if anything) is worth doing about it.
For the full picture on the insect itself — size, field marks, why the males dive-bomb you, sting risk — see our cicada killer wasp guide.
The nest is a burrow in the ground, and it has three consistent features.
The entrance hole. Roughly the diameter of a quarter — around half an inch to three-quarters of an inch across. It is noticeably round and clean-edged, not ragged. It usually enters the soil at an angle rather than straight down, so you often can’t see far into it.
The soil mound. This is the giveaway. The female pushes excavated earth out behind her and it piles up on one side of the opening in a U-shape or horseshoe, often three to six inches across. The soil is loose, fresh, and coarser than an anthill’s fine granules. On a mown lawn the mound flattens and spreads after rain or mowing, leaving a pale scuff of bare dirt around the hole.
The company it keeps. Cicada killer nests come in clusters. Because the females are picky about soil, dozens of burrows often appear within a few square yards while the rest of the yard has none.
Put together, a typical find is a bare, sunny strip of thin turf — the edge of a driveway, a south-facing bank, the sand under a swing set — pocked with round holes, each with its own little apron of dumped soil, with big rusty-and-yellow wasps cruising a foot above the grass.
Females choose nest sites on physical criteria, and knowing them tells you both where to look and why your yard was picked:
That list is also a list of the most common problem spots: sandboxes, volleyball courts, golf course bunkers and tee boxes, mulch bed margins, the seams between patio pavers, and thin turf under trees where grass never quite establishes.
This is the identification that actually matters for your safety, because the response to each is completely different. Both produce a hole in the ground with wasps going in and out; almost everything else differs.
| Cicada killer nest | Yellow jacket ground nest | |
|---|---|---|
| Structure | One burrow per female | One paper comb nest, hundreds to thousands of wasps |
| Entrance | ~Quarter-sized, round | Often smaller, ragged, sometimes an old rodent hole |
| Soil mound | Distinct horseshoe of loose soil | None — workers carry debris away |
| Number of holes | Many separate holes in a patch | Usually a single opening |
| Traffic | One large wasp per hole, intermittent | A steady stream of small wasps at one opening |
| Wasp size | 1.5–2 in, rusty red and black with amber wings | ~0.5 in, crisp black and yellow, clear wings |
| Defensive? | No | Yes — will swarm and sting repeatedly |
| Peak season | July to early September | Late summer into fall, largest in September |
The two fastest checks: look for the mound, and count the wasps per hole. A pile of excavated soil beside a big hole means a solitary digger. Many small wasps funneling in and out of one unmounded opening means a yellow jacket colony — back away and read our yellow jacket nest guide before doing anything else.
Get this wrong in the dangerous direction and the consequences are serious: mowing over or probing a yellow jacket nest is one of the most common causes of multiple-sting incidents in the US. When you aren’t certain, treat any ground nest as a yellow jacket nest until you’ve watched it from a safe distance.
Plenty of things dig holes in turf during summer. Before deciding you have a wasp problem, rule out:
One near-miss worth flagging: scoliid wasps are the other insect commonly reported as “wasps flying low over my lawn” in late summer. They cruise in slow figure-eights just above the turf but don’t build burrows — they’re searching for beetle grubs to dig down to and parasitize. If you see low-flying wasps but find no holes and no mounds, scoliids are the likely answer, and their presence hints at a grub population in the soil.
For a broader walk-through of everything that nests below grass level, see wasps that live in the ground and our underground wasp nest guide.
The visible entrance is the small part. Below it, a cicada killer burrow is a substantial piece of engineering.
The main tunnel runs downward at an angle, typically reaching six to twelve inches deep, then turns and branches into side passages ending in oval brood cells. A single well-developed burrow can total several feet of tunnel with ten or more cells, and a female may move several pounds of soil building it — an enormous excavation for an insect that weighs about as much as a paperclip. A female may also dig more than one burrow during her few weeks as an adult.
Then she provisions it. She hunts an annual cicada in nearby trees, stings it to permanent paralysis, and hauls it back — often climbing a tree or fence to gain height, because a loaded female can barely stay airborne. This is the “wasp dragging something huge across the lawn” that generates so many phone calls.
Each cell gets one egg laid on a paralyzed cicada, then gets sealed. The provisioning is calibrated to the offspring’s sex: cells destined to produce females, which are much larger, are stocked with two or three cicadas, while cells producing males typically get one. The female controls this — she determines the sex of each egg as she lays it.
The egg hatches in a couple of days, and the larva feeds on the still-living cicada for roughly one to two weeks. It then spins a tough brown cocoon and stays there. It overwinters underground as a dormant prepupa, pupates in spring, and emerges as an adult the following summer.
Two practical consequences follow from that timeline:
For nearly every household, no.
Males cannot sting at all. In wasps and bees the stinger is a modified egg-laying organ, so only females have one. The wasps that hover at eye level, chase each other in tight aerial spirals, and fly straight at you when you walk across the lawn are males defending territory from other males. It is pure bluff. They are the reason cicada killers have a fearsome reputation and the reason that reputation is undeserved.
Females can sting but almost never do. A female’s sting is a hunting tool, and she is not nest-defensive the way a social wasp is. She will tolerate mowing, gardening, and foot traffic a few feet from her burrow. Stings essentially require handling her, stepping on her barefoot, or pinning her against skin. On the Schmidt sting pain index, the cicada killer ranks toward the low end — below both the yellow jacket and the paper wasp, despite being several times their size. Our wasp sting pain scale puts the common species side by side.
The nest causes no structural damage. Cicada killers don’t chew wood, don’t nest in walls or attics, and don’t expand a nest over time. The realistic damage is cosmetic: a heavily used aggregation loosens soil and leaves a pitted, scuffed lawn, and on a putting green or a sand bunker that matters more than it does on a back slope.
Sensible precautions where there’s an active aggregation:
If a sting does happen, treat it like any wasp sting: wash the site, apply a cold compress, and take an oral antihistamine for itching. Our wasp sting treatment guide covers the full protocol and the symptoms that mean you need emergency care.
Cicada killers are beneficial insects on a short clock. Adults are active for roughly six to eight weeks and die off by early September on their own — often before an ordered treatment would even arrive. They suppress cicada numbers (cicada egg-laying damages young tree branches), they aerate compacted soil, and the adults feed on nectar and act as minor pollinators. A burrow aggregation on a back bank, a wooded edge, or an area nobody walks through is best left alone.
Where the nests are genuinely in the way — a play area, a heavily used lawn, a sand-based sports surface — the effective approach is habitat modification, because it addresses why the females chose the spot:
Filling the holes during the season doesn’t work. A female simply re-excavates, usually within a day. Stepping on the mounds accomplishes the same nothing.
For a large aggregation on a surface people actually use, the targeted approach is treating individual burrow entrances with an insecticide dust labeled for ground-nesting wasps, applied at dusk when females are inside, and always according to the product label. Dust works where sprays don’t because returning wasps track it into the tunnel.
Before anyone applies anything, confirm the species — mistaking a yellow jacket colony for cicada killers is the dangerous error, and it goes badly fast. If the aggregation is large, near a doorway, or you’re not confident in the ID, our wasp exterminator guide covers when a professional is worth calling and what to expect. For timing considerations on any ground nest treatment, see the best time to spray a wasp nest.
| Period | What’s happening | What you’ll see |
|---|---|---|
| Late June–early July | Males emerge first, set up territories | Large wasps patrolling low over turf; no holes yet |
| Mid-July | Females emerge, mate, begin digging | New holes and fresh soil mounds appear |
| Late July–August | Peak provisioning | Most burrows active; females hauling cicadas; peak complaints |
| Early September | Adults die off | Activity stops abruptly; holes remain but are empty at the surface |
| September–June | Larvae and prepupae develop | Nothing visible; old holes weather shut |
Local timing tracks the cicada emergence, so the burrows appear once the cicadas start singing overhead — a reliable cue that runs a few weeks earlier in the South and later in the northern part of the range. Our guide to when wasps are most active compares this with the very different seasonal curve of social wasps, which peak much later.
How many wasps live in one cicada killer nest? One adult female. She digs it, provisions it, and works alone. The larvae in the cells won’t emerge until the following summer, so at any given moment a burrow holds one adult and a set of sealed brood cells.
Why are there so many holes if they’re solitary? Because suitable soil is patchy. Dozens or even hundreds of unrelated females may dig in the same favorable spot. This is an aggregation, not a colony — a crowd of independent neighbors, none of them defending anything shared.
Should I fill in the holes? Not during the season; she’ll just dig them out again. Improving turf density between seasons is what actually reduces next year’s numbers. Old holes from a finished season weather shut on their own.
Do cicada killers come back to the same nest every year? No individual reuses a burrow, but the site is reused, because next year’s adults emerge from the soil they were laid in. That’s why a spot can host wasps for many consecutive summers until the ground changes.
Will they nest in my house or walls? No. Cicada killers are strict ground-nesters and need diggable soil. They occasionally exploit sand between patio pavers or the loose fill behind a retaining wall, but they don’t nest in structures. If you’re seeing wasp nests on eaves, siding, or in wall voids, see what a wasp nest looks like — that’s a different species.
Is it safe to mow over the holes? Yes. Females aren’t nest-defensive and will move out of the way; males can’t sting. Mowing a yellow jacket nest is a very different matter, which is the reason to confirm the ID first.
Something red and black is crawling among the burrows — what is it? Most likely a velvet ant (a wingless female wasp), several species of which parasitize the nests of ground-nesting wasps. Unlike the cicada killer, a velvet ant delivers a genuinely painful sting if handled. See our velvet ant guide.
Are they harming my lawn? Only cosmetically, and only where the aggregation is dense. Loosened soil and scuffed patches around the entrances are the extent of it. Cicada killers don’t feed on grass or its roots.