If the wasps are flying low over your grass in loops and figure eights, they are almost certainly hunting beetle grubs in the soil. Those are scoliid wasps, and they rarely, if ever, sting people. Big wasps digging holes in bare, sunny patches are cicada killers, which are also reluctant to sting.
The one to take seriously is a steady line of yellow-and-black wasps flying in and out of a single hole in the ground. That's a yellowjacket nest, and by late summer it can hold several hundred workers that sting repeatedly to defend it.
Most people asking this question have noticed the same thing: it's August, and the lawn seems to be full of wasps. That timing is the first clue. Nearly every wasp that turns up in a Carolina or Virginia yard peaks in late summer, but they are not all the same insect, and they are not all a problem. What they are doing tells you which one you have.
Which Wasp Is It? Watch What It's Doing
| What you see | Most likely | Stings? | What to do |
|---|---|---|---|
| Dozens of wasps flying in low loops a few inches over the grass, landing and digging | Scoliid wasps, such as the blue-winged wasp | Rarely, if ever | Nothing. They are eating your grubs |
| Very large wasps, over an inch long, digging holes in bare, sunny, dry soil with a U-shaped mound of dirt at the entrance | Cicada killers | Males can't. Females only if handled | Thicken the turf and water the bare spots |
| A steady stream of yellow-and-black wasps going in and out of one hole, with no dirt pile | Yellowjackets | Yes, repeatedly | Keep people and pets away and have it treated |
| Wasps around the eaves, deck rails or a grey paper ball in a tree | Paper wasps or bald-faced hornets | Yes, near the nest | Depends where the nest is. See below |
| Wasps crawling on fallen fruit, trash cans and drinks | Yellowjackets foraging | Yes, if trapped against skin | Remove the sugar sources |
Wasps Flying Low Over the Grass: Grub Hunters
The wasps that cruise a few inches above a lawn, looping back and forth all afternoon, are scoliid wasps. The most common one in the Southeast is the blue-winged wasp, Scolia dubia: about an inch long, black, with dark wings that flash blue in sunlight, a rusty-orange rear half and two yellow spots near the middle of the abdomen.
They are not nesting in your lawn. They are hunting in it. The female digs down through the soil, following grub tunnels, until she finds a beetle grub. She stings it to paralyze it, lays an egg on it and moves on to the next one. When the egg hatches, the wasp larva eats the grub. The males are the ones flying the loops, patrolling for females.
NC State's turf entomologists put it plainly: scoliids have no nest-guarding instinct, and they "rarely, if ever, sting people." Their advice is to leave them alone, because they are reducing your grub population for you. They are active in the Carolinas from June to October and most abundant in August.
There's a useful message in them, though. A lot of scoliid wasps means a lot of grubs under your grass. Those are the larvae of green June beetles and similar scarab beetles, and a heavy grub population can thin turf and draw moles and armadillos that dig for them. If the wasps bother you, the fix is the grubs, not the wasps. Our guide to getting rid of June bugs covers the grub side.
Big Wasps Digging Holes in Bare Spots: Cicada Killers
If the wasps are huge, well over an inch and up to about two inches long, with a rusty-red thorax, amber wings and yellow bands on a black abdomen, you have cicada killers. They alarm people more than any other wasp because of their size and because the males dive-bomb anyone who walks through their patch.
The bluster is mostly show. NC State Extension notes that the males defend their burrows by dive-bombing but "will not sting," and females sting only when mishandled. Clemson's Home & Garden Information Center calls them beneficial, since they remove plant-feeding cicadas, and doesn't recommend control unless they pose a threat to vulnerable people or pets.
What gives them away is the digging. Females pick bare, well-drained, light-textured soil in full sun and dig a burrow with a U-shaped mound of loose soil around the entrance. They are solitary, so each hole belongs to one female, but many females can nest close together in a good patch, which is why a yard can suddenly seem full of them. Females stay active for about two months in mid to late summer.
The fix is the bare patch. NC State notes that cicada killers don't like wet soil, and that lime and fertilizer to thicken the turf can eliminate an infestation. Water the bare areas regularly, reseed or sod them, and next summer the wasps will look elsewhere. Mulch or ground cover over a bare, sandy strip works too.
A Steady Line In and Out of One Hole: Yellowjackets
This is the one to take seriously. Yellowjackets are social wasps. Instead of one female per burrow, a single ground nest holds a colony, often built in an old rodent burrow or other soil cavity. According to Clemson, colonies in South Carolina start in April or May when an overwintered queen emerges, and by August a colony may reach several hundred workers.
You can tell a yellowjacket nest from a cicada killer burrow in a few seconds of watching from a distance:
- Traffic. Yellowjackets fly in and out of the same opening constantly, one after another. A cicada killer burrow sees one wasp come and go.
- No dirt pile. A yellowjacket entrance is usually just a hole, often at the base of a shrub, a stump or a landscape timber. Cicada killers leave a mound of fresh soil.
- Size and color. Yellowjackets are about half an inch long, glossy and sharply banded black and yellow. They look like a smaller, tidier version of the cartoon wasp.
The danger is defense. Unlike a honeybee, a yellowjacket has a smooth stinger it can use again and again, and a colony will pour out to defend a disturbed nest. The usual way people find one is by running a mower or string trimmer over the entrance. If you spot a nest, mark it, keep children and pets away, and mow around it until it's dealt with.
Treating a ground nest safely is a job for a professional. Clemson advises applying insecticide late in the evening or at night, when all the foragers are inside, because any daytime attempt meets returning workers ready to defend the colony. Our wasp and yellowjacket control service handles ground nests, and our guide on dealing safely with a wasp nest explains what not to try yourself.
Wasps Around the House, Not the Grass
Some yard wasps never touch the lawn. Paper wasps build open, umbrella-shaped combs under eaves, porch ceilings and deck rails, and they defend the nest if you get close. Bald-faced hornets, which are really a kind of yellowjacket, build an enclosed grey paper ball in trees and shrubs.
A paper wasp nest on a far corner of the house can often be left alone; one over the front door can't. For telling these apart, see our Southern guide to yellowjackets, wasps and hornets.
Why There Are More Wasps in Late Summer
All of these peak at the same time for the same reason: late summer is when their year pays off. Scoliids are most abundant in August. Cicada killers hunt through mid to late summer, when cicadas are singing. Yellowjacket colonies hit their maximum size in late summer and early fall.
That peak is also when yellowjackets become a nuisance at picnics. Clemson explains that as the season turns, their normal food runs short and they switch to scavenging, which is why they show up at soda cans, fallen fruit and open trash in September. A few habits cut down on yellowjacket foragers:
- Pick up fallen fruit under fig, pear, apple and muscadine vines. Fermenting fruit is a magnet.
- Keep trash and recycling lidded, and rinse cans and bottles before they go in the bin.
- Cover drinks and food outdoors, and check a can before you sip from it.
- Don't leave pet food outside. It's protein, and workers carry it back to feed the larvae.
None of this affects the grub hunters or cicada killers, which aren't interested in your food at all.
Sources: NC State TurfFiles, Scoliid Wasps Hovering Over Lawns; NC State Extension, Cicada Killer Wasps in Turf (Brandenburg and Billeisen); Clemson HGIC 2486, Yellowjackets (Hood); Clemson HGIC, Eastern Cicada Killer.
Frequently Asked Questions
They are almost always scoliid wasps, such as the blue-winged wasp, hunting beetle grubs in the soil. The males fly low loops looking for females, and the females dig down to lay eggs on grubs. A lot of them usually means a lot of grubs under the turf.
Usually not. Scoliid wasps rarely, if ever, sting people, and male cicada killers can't sting at all. The exception is a yellowjacket ground nest, which you can spot by a steady stream of wasps flying in and out of one hole. Keep away from that one.
Watch the traffic from a distance. A yellowjacket nest has wasps coming and going constantly through one opening and usually no dirt pile. A cicada killer burrow belongs to one large wasp and has a U-shaped mound of loose soil around it.
It depends on the wasp. Cicada killers leave when bare, dry patches are watered and the turf is thickened. Scoliid wasps leave when the grubs they hunt are gone. Yellowjacket ground nests should be treated by a professional, ideally at night when the workers are inside.
Late summer is the peak for all of them. Scoliid wasps are most abundant in August, cicada killers hunt through mid to late summer, and yellowjacket colonies reach several hundred workers by August and start scavenging sugary food as their normal food runs short.
For yellowjackets, food: fallen fruit, open trash, sugary drinks and pet food. For scoliid wasps, beetle grubs in the lawn. For cicada killers, bare, sunny, well-drained soil to dig in. Removing the specific attraction works better than traps.
Photo credits: Christina Butler, CC BY 2.0, via Wikimedia Commons; Dmitry Brant, CC BY-SA 4.0, via Wikimedia Commons; Xorx, CC BY-SA 4.0, via Wikimedia Commons; Rhododendrites, CC BY-SA 4.0, via Wikimedia Commons.