Is it safe to knock down a wasp nest myself?

It depends entirely on what kind of nest it is and how big it has gotten. A new paper wasp nest in May — a bare, open comb the size of a walnut with two or three wasps on it — is genuinely a low-risk job for a homeowner with a can of aerosol and an escape route. A bald-faced hornet nest the size of a basketball in August is not, and neither is a yellowjacket nest in the ground. Those colonies hold hundreds of workers, they defend aggressively, and they pursue. The general rule out here: if the nest is enclosed rather than open, or bigger than a softball, or you cannot see where the entrance is, leave it.

Why are wasps so much more aggressive in late summer?

Two things happen at once. The colony reaches its maximum size in August and September, so there are simply far more workers to defend it. And the queen stops laying worker brood, which cuts off the sugary secretion the larvae had been feeding the adults — so the workers switch to scavenging sugar from your soda can, your grill, and your garbage. A larger, hungrier, more crowded colony with nothing left to do but defend itself is why the calls spike right as everyone is trying to eat outdoors.

How do I tell a yellowjacket from a honey bee?

Look at the body, not just the color. A honey bee is fuzzy, thick-waisted, and a duller golden brown; it is carrying pollen and it is on flowers. A yellowjacket is smooth, shiny, sharply banded black and yellow, has an obvious narrow waist, and it is on your food, your trash, or your can of pop. That distinction matters: honey bees are pollinators and should be relocated by a beekeeper, not killed. If you are unsure, a photo settles it in seconds.

What is the nest in the ground that my mower disturbed?

Almost certainly yellowjackets. Several of Wisconsin's yellowjacket species nest underground, often taking over an abandoned rodent burrow, and the only visible sign is a steady stream of wasps going in and out of a hole in the lawn, a bank, or the edge of a field. They are the reason so many of our stinging-insect calls come from someone mowing, weed-whipping, or landscaping. Ground nests are the least suitable of all for DIY treatment: you cannot see the colony, you cannot judge its size, and the vibration of equipment alone will set it off.

Will the nest die on its own over winter?

Yes, and this genuinely matters for deciding what to do. A Wisconsin wasp or hornet colony is annual. Hard frost kills the workers and the old queen, and only newly mated queens survive, tucked away somewhere sheltered to start fresh nests in spring. The nest itself is not reused. So a nest high in a tree, far from any doorway or walkway, where nobody will disturb it, can reasonably be left to die in October. A nest by the back door in July absolutely cannot — you have three more months of season to get through.

Do you kill honey bees?

No. If it is a honey bee colony we say so and point you to a beekeeper who can take the swarm or the colony, because a honey bee swarm is a valuable thing and killing one is the wrong answer. What we treat are the wasps and hornets — paper wasps, yellowjackets, bald-faced hornets — and the occasional carpenter bee doing structural damage. Being told you do not need us is a normal outcome of a call to BugBoss.

Does knocking the nest down solve it?

Rarely, and it often makes the situation worse for a day or two. Knocking a nest down without treating the colony releases several hundred angry workers into the exact space you were trying to make safe, and the survivors will frequently rebuild within a few feet of the original site because the location is what attracted them. The nest also has to come down all the way — a fragment of comb left in a soffit or a wall void will draw dermestid beetles and other scavengers later. Treat first, remove after.

What if the nest is inside a wall or soffit?

That is the case to stop and call about rather than experiment with. A nest in a wall void or soffit cannot be seen or measured, the wasps are moving through a cavity that connects to other parts of the structure, and the single most common homeowner mistake — sealing the entrance hole — drives the colony to chew through into the living space instead. It needs to be treated at the entry point, left open until the colony is dead, and only then sealed.

That Nest on Your Eave: When a Wisconsin Wasp Nest Can Wait and When It Can't

By August a Wisconsin wasp nest holds hundreds of workers and the colony is at its most defensive. Here's how to tell a paper wasp from a bald-faced hornet from a ground nest of yellowjackets, and which ones you should not go near.

The nest was always there — August is just when you notice it

Almost nobody calls about a wasp nest in May. In May the nest is a bare gray comb the size of a walnut with a single queen sitting on it, tucked up under the porch roof where nobody looks. By the second week of August the same nest is the size of a dinner plate with a couple of hundred workers on it, everybody is eating on the deck, and it has become the most urgent problem on the property.

That is the seasonal shape of stinging-insect work in Northeast Wisconsin, and it is why our stinging insect calls cluster so hard into July, August, and September. The colony has been growing all summer on a curve that only becomes obvious at the top of it.

Understanding that curve is the whole basis for deciding what to do. So is knowing what you are actually looking at, because “wasp nest” covers four very different situations with four very different levels of risk.

Know which one you have — it changes everything

Paper wasps: the open umbrella comb

This is the nest most people picture. An open, unwrapped comb of gray hexagonal cells, hanging from a short stalk, usually under an eave, a porch ceiling, a deck rail, inside a grill you have not opened since spring, or in the frame of a swing set. You can see the cells and you can see the wasps standing on them — typically a modest number, often under thirty even in late summer.

Paper wasps are the least aggressive of the group. They defend the nest if you get close, but they do not patrol and they do not pursue far. Their nests stay comparatively small. A homeowner can reasonably deal with a small paper wasp nest in an accessible spot, at dusk, with an aerosol rated for the distance and a clear path to walk away.

The complication is location. A paper wasp nest inside the handle of a patio door, in a mailbox, or under the rail you grab going down the deck steps is a stinging incident waiting to happen regardless of the species’ temperament, because you are going to put your hand on it eventually.

Bald-faced hornets: the gray football in the tree

If you are looking at a large, fully enclosed, teardrop or football-shaped gray paper envelope with a single opening near the bottom, you have bald-faced hornets — which, despite the name, are a large black-and-white yellowjacket rather than a true hornet.

This is the one to leave alone. Bald-faced hornets build big — a mature nest can hold several hundred workers — they are strongly defensive of the nest area rather than just the nest itself, and they will pursue an intruder well away from it. They can sting repeatedly. Vibration alone, from a lawnmower or a ladder set against the same tree, is enough to bring them out.

There is no version of a homeowner successfully spraying a mature bald-faced hornet nest from a stepladder that we want to be part of.

Yellowjackets in the ground: the nest you cannot see

Yellowjackets build both aerial and subterranean nests, and out here in farm and field country the ground nests are the ones that cause trouble. The colony takes over an old rodent burrow or a void under a stump, a slab, a bale, or the edge of a shed, and the only sign is wasps streaming in and out of a hole.

Every summer this is the same call: somebody was mowing, weed-whipping, tilling a garden edge, or moving firewood, and the ground erupted. Because the nest is invisible until it is disturbed, you get no warning and no chance to back off first.

Ground nests are also the worst candidate for DIY treatment, for a reason that is worth stating plainly: you cannot see how big it is. A garden-hose-and-gasoline approach — and people do try it — is dangerous, illegal to do with fuel, and frequently fails while enraging several hundred wasps at ankle height.

Yellowjackets in a wall or soffit

The other yellowjacket problem is structural. The colony sets up in a wall void, a soffit, a box gutter, or behind fascia, with the workers using a gap in the siding or a weep hole as the door.

The mistake almost everyone makes here is to seal the hole. It seems obvious — block the door, problem over. What actually happens is that a few hundred wasps that cannot get out the way they came in start chewing, and the softest material between them and daylight is very often the drywall on the inside of your bedroom.

The entrance has to stay open until the colony is dead. Seal it after, not before.

The late-summer aggression is real and it has a cause

People are not imagining that wasps get worse in August. Two things change at the same time.

First, the colony is at its peak. A nest that had a dozen workers in June has hundreds by late August, so the same amount of disturbance produces a much larger response.

Second, the food supply flips. Through most of the summer, adult workers hunt insects to feed the larvae, and in exchange the larvae produce a sugary secretion the adults live on. Late in the season the queen stops laying worker brood, the larvae run out, and that sugar supply disappears. The workers go looking for sugar somewhere else — and somewhere else is your can of pop, the sweet corn on the picnic table, the fallen apples under the tree, the garbage can by the garage, and the fruit in the orchard.

That is why late-summer wasps get in your face at a cookout when the same wasps ignored you in June. They are not defending anything. They are foraging, and you are the sugar.

Which nests can actually wait until frost

A Wisconsin wasp or hornet colony is annual. It does not survive winter. Hard frost kills the workers and the founding queen, and only the newly mated queens live on, overwintering somewhere sheltered — under bark, in a woodpile, in a wall void, sometimes in an attic — to start over alone in spring. The nest is not reused the next year.

That fact is practically useful, because it means some nests genuinely can be left alone:

High in a tree, well away from the house, walkways, play areas, and the mowing line. Nobody is going to bump it. It will be empty by November and can come down over winter.
In a fencerow or woodlot corner of a farm property that nobody works close to for the rest of the season.

And some cannot wait, no matter how late in the year it is:

Anywhere within about ten feet of a door, a walkway, a deck, a patio, or a play area. Proximity, not species, is the deciding factor here.
In the ground anywhere you mow, till, or work. Equipment vibration is the trigger.
Inside the structure — wall, soffit, attic, box gutter.
Anywhere on a property with someone who has a known sting allergy. There is no acceptable level of risk in that case, and it is worth saying to us on the phone so it is treated as urgent rather than routine.
Around livestock, a horse paddock, or a kennel run, where a disturbed ground nest can cause a serious animal injury and a panicked animal can hurt someone.

What actually works, and what to skip

The hardware-store aerosol. These have a place: a small, open, accessible paper wasp nest, treated after dark when the colony is home and calm, from the maximum distance the can supports, with the wind at your back and a clear route inside. They are not a solution for an enclosed nest, a nest you have to climb to, or a ground nest.

Do it at dusk or before dawn, never midday. Foragers are out during the day, which means the ones you did not kill come home to a wrecked nest and no reason to be calm. At night the colony is together and quiet.

Never on a ladder. This is worth its own line, because the worst outcomes we hear about are not sting injuries. They are fall injuries. Being stung once at the top of an extension ladder is how people break bones. If it needs a ladder, it needs somebody else.

Skip the traps as a control method. Hanging yellowjacket traps can reduce the nuisance foragers around a specific spot — a deck, a dumpster, a serving area — and that is a legitimate use. What they do not do is kill the colony. Baited traps placed close to the house can also pull more wasps toward the area than they catch. Put them at the far edge of the space you are protecting, not next to the picnic table.

Skip the fake-nest decoys and the gasoline and the burning. The decoys have no reliable effect. Fuel in a ground nest is dangerous, contaminates soil, and is illegal to use as a pesticide.

What BugBoss does about it

Brian handles stinging insects across the Clintonville, Shawano, New London, and Waupaca area constantly through the second half of summer, and the job is fairly consistent:

Identify it properly first, including ruling out honey bees, which get a beekeeper rather than a treatment.
Find the actual nest, which on a structural job means watching the flight line back to the entry point rather than treating where the wasps are landing.
Treat the colony at the nest with the right material for the situation and the right protective equipment, at the right time of day.
Remove the nest once the colony is dead, where it is accessible — a nest left in a void draws scavenger insects later.
Close the entry point after, not before, and note the other gaps in the same soffit or fascia run that will be next year’s nest site.

Sting incidents are also the reason this is one of the few things we will move quickly on. If somebody in the house is allergic, say so when you call.

Worth knowing: stinging insects are covered under the BugBoss guarantee on treated structures for quarterly customers, but nests elsewhere on the property are a separate call. The guarantee page sets out exactly where the line falls, because a guarantee you have to argue about is not worth having.

Prevention for next year, which starts in spring

The single highest-value thing you can do about wasps is not done in August at all. It is done in late April and May, when the founding queens are out looking for a site and the nests are the size of a walnut with one wasp on them.

Walk the eaves, soffits, porch ceilings, deck rails, and outbuildings once a week in May. A nest at that stage is trivially removed.
Open and check the things that sat closed all winter before you need them: the grill, the playset tubes, the mailbox, the meter box, the shed, the boat cover, the empty flowerpots stacked by the garage.
Seal the gaps that let them into voids — torn soffit vents, gaps at fascia and frieze board, unscreened attic and gable vents, siding gaps at utility penetrations. Same work that keeps fall invaders and bats out, done once.
Keep the sugar sources managed through late summer: lidded garbage cans, cleaned recycling, fallen fruit picked up, spills rinsed off the deck.
Look before you mow. Especially along field edges, banks, stumps, and the ground next to outbuildings.

Ten minutes with a broom handle in May is the cheapest stinging-insect control there is.

When to just call

Call rather than experiment if the nest is enclosed, if it is in the ground, if it is inside the structure, if it needs a ladder, if it is near a door or a play area, if there are animals or an allergic person on the property, or — honestly — if you are going to be nervous doing it. Being nervous at the wrong moment is how people get stung.

Reach Brian directly at 866-BUGBOSS, or send the details through the contact form and he will get back to you. No long-term contract, and you are talking to the person who is going to do the work.