How to Get Rid of Ground Wasps and Yellowjacket Nests in Your Barrie Lawn

Posted on 2026-08-31

You went to mow the lawn and suddenly you're getting stung by wasps coming out of the ground. That's yellowjackets, and late August is exactly when they turn mean. To get rid of ground wasps safely, you need to find the nest entrance, stay back from it, and treat the whole underground colony rather than just spraying the wasps you can see. A can of store spray at the hole usually makes them angrier and rarely reaches the nest.

Here's what's really going on. A yellowjacket colony that started as one queen in spring hits its biggest size right now, often thousands of workers. At the same time, the insects they normally feed on are dying off, so the colony gets hungry and defensive. That's why they seem calm all summer and then turn aggressive around your patio, deck, and lawn in the last weeks of August. And because the nest sits underground, most people never spot it until they're right on top of it.

How do I find a ground wasp nest in my yard?

Look for a steady stream of wasps flying in and out of one small hole in the ground, usually about the width of a finger. Watch from a safe distance in the morning or early evening when traffic is heaviest. The entrance is often hidden in a lawn, under a shrub, along a garden edge, or beside a foundation. Follow the wasps back to the hole rather than chasing the ones flying around.

The mistake most people make is watching a single wasp bouncing around the deck and assuming the nest is close by. Foragers travel well away from home looking for food and sweet drinks, so the one bugging you at the picnic table might live across the yard. The reliable trick is to stand still and look for the traffic pattern. A real nest entrance has wasps coming and going in a consistent line, like planes at a runway. Mark the spot from several feet back, then leave it alone until it's treated. Never pour anything down the hole or block it, since that traps the colony and sends them looking for another way out, sometimes into your walls.

Why don't store-bought wasp sprays work on ground nests?

Those sprays are made for nests you can see and hit head-on, like one tucked under an awning or eavestrough. A ground nest is a different problem. The colony sits well below the surface, often in an old rodent burrow, so the spray only reaches the entrance. The queen and most of the workers are down in the deeper chambers where nothing touches them, and the nest is back to normal within a few days.

The bigger issue is that standing over the hole to spray puts you right in the spot where people get stung. Yellowjackets can sting again and again, and a large late-season nest will send a swarm straight up at whoever is leaning over it. A professional wasp exterminator gets around both problems by placing a dust at the entrance that the workers carry down into the nest themselves. It spreads through the whole colony and wipes it out at the source, and it's done safely at dawn or dusk when the wasps are least active.

What should I do about ground wasps until the exterminator arrives?

Until the nest is treated, the safest move is to give it a wide berth and resist the urge to deal with it yourself. Most of the trouble people run into comes from disturbing the entrance or provoking the colony while it's still active.

• Don't cover, flood, or burn the entrance, since it just makes the colony dig a new way out, sometimes toward the house
• Hold off on mowing near that corner of the yard until the nest is gone
• Cover drinks, pick up fallen fruit, and keep the garbage and recycling bins latched, since late-summer yellowjackets are hunting for sugar and protein
• Move away slowly if a wasp comes close instead of swatting, because a crushed wasp releases a scent that draws the others in

When should I call a wasp exterminator in Barrie?

A ground nest won't sort itself out. The colony stays active and aggressive until a hard frost, which is still months away here, and it only grows more defensive as the weeks go on. Trying to handle it yourself usually means more stings and a nest that comes right back, so you are best to call an exterminator now to avoid having to share your yard and home with yellowjackets all fall.

We handle ground wasp treatment in Barrie and throughout Southern Ontario, including the larger rural lots where these nests show up most, from pest control in Innisfil to wasp control in Alliston and Cookstown. If yellowjackets have taken over your yard, book a wasp treatment with a local exterminator and get the nest dealt with at the source.​​​​​