Wasp and Hornet Nest Removal in Chester County: Identify the Species, Then Treat the Nest

Four stinging insects cause most nest calls in southeastern Pennsylvania

Most people say "wasps" for anything yellow and black that stings. The species matters, because each one builds in a different place and defends its nest differently. These four account for most nest problems at homes in Chester County, Montgomery County and Delaware County.

• Paper wasps (Polistes species, including the native northern paper wasp and the European paper wasp). Open, umbrella-shaped combs with no paper cover, hung under eaves, porch ceilings, deck railings, grill lids and shutters. Colonies usually stay in the dozens, though Penn State notes some grow past 200.
• Bald-faced hornets (Dolichovespula maculata). Gray, football-shaped paper nests in shrubs, trees and sometimes on the side of a house. Penn State describes nests up to 24 inches tall in Pennsylvania, with a few hundred workers by late summer. They are technically aerial yellow jackets, not true hornets.
• Eastern yellow jackets (Vespula maculifrons). Mostly underground in lawns, garden beds, stone walls and creek banks, and sometimes inside a wall void or crawlspace. Colonies can reach into the thousands, and these are the insects that swarm soda cans and trash in late summer.
• European hornets (Vespa crabro). The large brown and yellow hornet that hits porch lights and windows after dark. Penn State calls it the only nocturnal wasp in the state. It nests in hollow trees, attics and wall voids, with 200 to 400 workers by the end of the season.

How the nest season runs from May to the first hard frost

Every paper wasp, hornet and yellow jacket colony here lasts one season. A fertilized queen spends the winter alone in a protected spot, often under loose bark or in a shed wall. In May she starts a small nest by herself and raises the first workers. Penn State Extension gives May as the month paper wasp queens establish nests, and May or June for eastern yellow jackets.

A nest the size of a golf ball in May is easy to miss. By August the same colony can fill a wall cavity or a hole the size of a basketball under the lawn. Penn State notes that wasps become more defensive later in the summer and into fall, when local food runs short. That is why most stings around decks, pools and gutters happen in August and September, and why a nest nobody noticed in June suddenly becomes a problem at a Labor Day cookout.

Workers and the old queen die off around the first hard frost. New queens leave to overwinter, and the old nest is not reused. A nest you find in November is almost always empty.

Do not seal a wall-void nest entrance while the colony is active

The most common mistake we see is caulk or expanding foam pushed into the hole where yellow jackets or European hornets are going in and out of siding, a soffit gap or a weep hole in brick. It seems like the obvious fix, but it usually makes things worse.

Penn State Extension warns never to try to seal wasps inside a wall or the ground, because they can dig a new way out. A colony with a blocked entrance chews through whatever is softest. Behind vinyl siding and sheathing, that can be the drywall in a bedroom or the ceiling of a finished basement, and the wasps come out indoors.

If you see steady traffic in and out of one spot on the house, leave it open, keep people away from it and call us. We treat the colony through the entrance first. Once the nest is dead, we tell you when it is time to seal that gap, which is often best done over the winter.

Ground nests: yellow jackets in lawns, beds and stone walls

Ground-nesting yellow jackets use old rodent burrows, gaps under garden timbers, loose fieldstone walls and soft soil at the edge of a patio. The entrance is often no bigger than a quarter, and the colony below can be much larger than it looks. People usually find them by running a mower over the hole.

Pouring gasoline or boiling water into the hole, or stuffing it with a rock, tends to push the colony to open a second exit. Watch from a distance at midday to find the entrance, mark it with a flag from well back, and keep kids and pets out of that part of the yard until it has been treated.

Properties along wooded edges and creek banks see more of these nests. That includes a lot of homes around French Creek, the Perkiomen and the Brandywine, where lawns run straight into woods and old stone walls.

How C.R. Davis treats a wasp, hornet or yellow jacket nest

Every visit follows The Davis Inspection Standard, which starts with identifying the insect before anything is applied.

Identify the species and find the real entrance. A paper wasp comb, a bald-faced hornet nest in a holly and a yellow jacket colony in a wall void are three different jobs. We also look for second entrances on wall and ground nests.

Name what made the spot attractive. Open soffit returns, gaps where siding meets trim, a hollow porch column, a rotted fascia board, uncovered trash and fallen fruit all draw wasps. We point these out so they can be fixed after the season.

Place treatment in the nest itself, per the label. For exposed nests that means treating the comb or paper envelope. For ground and wall nests it means treating through the entrance into the colony. Treatment works best later in the day, when most foragers are back inside.

Tell you what happens next. Returning foragers may circle the entrance for a short time. We tell you how long to keep people and pets away from the treated area, per the label, when to remove an exposed nest and when to seal a wall or ground entrance.

Honey bees are pollinators: call us to identify them first

Honey bees (Apis mellifera) are not wasps. They are important pollinators, they are fuzzy and golden-brown rather than shiny yellow and black, and they build wax comb rather than paper. A single honey bee can sting only once.

If you have bees going in and out of a wall, or a cluster hanging from a branch or fence, call us to identify the insect before anyone sprays or seals anything. People often mistake yellow jackets for honey bees, and the reverse. Penn State warns that honey bees sealed into a wall can chew through drywall and come out inside the house.

A spring swarm, the football-sized cluster of bees resting on a limb, is a colony looking for a new home. Local beekeepers often collect swarms before the bees move into a wall or tree cavity.

Carpenter bees, cicada killers and other look-alikes

Large black and yellow bees hovering at the fascia or deck rail in April and May are usually carpenter bees, which drill round holes in bare wood rather than building a nest. See our page on carpenter bee holes in decks and trim for how that work differs.

Huge solitary wasps digging in sandy soil in July are often cicada killers. They rarely sting people and live alone rather than in a colony. Mud daubers build tube-shaped mud nests on garage walls and are rarely defensive. We identify these on site so you are not treating something that does not need it.

Cutting down on next year's nests

Colonies start from scratch every spring, so what you do in the off season matters. Penn State recommends making repairs over winter or early spring to block old colony entrances, once they are no longer active.

Seal gaps where siding meets trim, replace loose soffit vents and cap open porch columns. Keep trash and recycling bins closed, and pick up fallen fruit in late summer. Knock down small paper wasp starts in May, from a distance, before workers hatch. Homeowners on a year-round pest control plan can ask us to check eaves and deck undersides on spring visits.

• Walk the house in late May and look under eaves, railings and grill covers
• Mark any ground hole with steady traffic and keep the mower away from it
• Watch wall and soffit gaps for insects going in and out in July
• Seal old entrances between December and March, not during the season

Where we remove wasp and hornet nests

We work out of our headquarters on Silver Springs Road in East Pikeland Township, near Phoenixville, and serve homes and businesses across Chester County, Montgomery County and Delaware County, including West Chester, PA. Call (610) 935-9130 or send us a message and describe where the insects are going in and out.