The European hornet is the only true hornet living in Pennsylvania, and it’s been here since the 1840s. At 1 to 1.5 inches long, it’s the largest wasp you’re likely to encounter in the state, and its size alone tends to alarm people. But European hornets are well established across all of Pennsylvania and are a normal part of the local ecosystem, not an invasive threat on the level of the now-infamous northern giant hornet (formerly “murder hornet”) found in the Pacific Northwest.
How to Identify a European Hornet
European hornets have a distinctive color pattern that sets them apart once you know what to look for. The head, upper body, and “cheeks” are mahogany or reddish-brown. The face is yellow, the wings are brown, and the abdomen is banded yellow and black. Look closely at the black bands on the abdomen: they have teardrop-shaped extensions pointing toward the rear, a detail unique to this species. Queens reach about 1.5 inches, while workers are slightly smaller but still noticeably larger than any yellowjacket.
Common Look-Alikes
Several insects in Pennsylvania get confused with European hornets:
- Cicada killer wasps are similar in size but slenderer, with black abdomens marked by yellow splotches, reddish eyes, and amber wings. They’re solitary ground-nesters and rarely sting people.
- Bald-faced hornets aren’t actually true hornets. They belong to the yellowjacket family and are black with white facial markings, making them easy to distinguish once you get a good look.
- Yellowjackets are noticeably smaller (about half an inch) and have bright yellow-and-black patterns without the reddish-brown coloring.
Where They Nest
European hornets prefer enclosed cavities. Hollow trees are their natural first choice, but they readily move into barns, sheds, attics, and wall voids. Unlike bald-faced hornets, which build large, visible paper nests hanging from tree branches or eaves, European hornets rarely build exposed, free-hanging nests. They typically construct at the opening of a cavity rather than deep inside, and the visible portion is covered in coarse, tan, paper-like material made from chewed decayed wood.
A typical nest contains 1,500 to 3,000 cells. Colony size peaks in mid-September, when most nests have 200 to 400 workers, though large colonies can reach 1,000. These are annual nests. Every worker dies in the fall, and only fertilized queens survive the winter by tucking themselves under loose bark, inside rotting stumps, or in sheltered spots like attics. You may find multiple queens hibernating in the same location, but they overwinter individually. Come spring, each queen starts a brand-new nest from scratch. Old nests are never reused.
Behavior Worth Knowing
European hornets are predators. They hunt grasshoppers, flies, and even yellowjackets, making them genuinely useful for controlling other pest insects around your property. They feed captured prey to their developing larvae back in the nest.
The most unusual trait: European hornets are the only nocturnal wasp in Pennsylvania. They forage after dark and are commonly attracted to porch lights at night. If a large, buzzing insect keeps bumping into your outdoor light on a summer evening, it’s almost certainly a European hornet. This nighttime activity surprises most people and is often what prompts the “what is this thing?” search. They’re drawn to the light, not to you.
European hornets can also strip bark from shrubs and young trees to access sap, which occasionally causes cosmetic damage to ornamental plantings. This girdling behavior looks alarming but rarely kills established trees.
How Dangerous Is the Sting?
A European hornet sting hurts more than a yellowjacket sting, largely because of the hornet’s size and the volume of venom delivered. The venom contains proteins that damage cells on contact, which is what produces the immediate sharp pain, redness, and swelling. For most people, these symptoms fade within a day or two as the body breaks down the venom and repairs the tissue.
Some people experience a more dramatic local reaction: heavy swelling and redness that lasts several days to a week. This is unpleasant but not life-threatening. The serious concern is anaphylaxis, a whole-body allergic reaction that can include hives across the skin, difficulty breathing, throat swelling, and a sudden drop in blood pressure. Anaphylaxis requires immediate emergency treatment with epinephrine. The biggest risk factor is a previous allergic reaction to any stinging insect.
For a normal sting, a cold pack reduces swelling, over-the-counter hydrocortisone cream helps with itching, and an oral antihistamine can ease discomfort. If swelling persists beyond a few days or a red line extends outward from the sting site, that warrants medical attention.
European Hornets Are Not Typically Aggressive
Despite their intimidating size, European hornets are far less aggressive than yellowjackets. They generally ignore people unless the nest itself is disturbed or they feel physically threatened. Most stings happen when someone accidentally grabs a hornet, steps on one, or gets too close to a nest entrance. If you see one foraging in your yard or hovering around a light, it poses very little risk. Simply moving away is enough.
That said, they will defend their nest. If you notice steady hornet traffic flowing in and out of a wall void, tree cavity, or attic opening, keep a distance of at least 10 to 15 feet and stay out of their flight path.
Removing a Nest Safely
If a nest is in a location where it poses a real problem (inside a wall, in a shed you use daily, directly above a doorway), removal is straightforward but carries real sting risk. Hiring a pest control professional is the simplest option. In Pennsylvania, nest removals typically cost over $100 depending on the situation. The technician assumes the sting risk, carries the right equipment, and has liability insurance covering property damage during treatment.
If you choose to handle it yourself, plan during the day but act at night. After dark, all workers are inside the nest, they’re less likely to fly, and they have poor vision. Aerosol wasp and hornet sprays sold at hardware stores can reach 15 to 20 feet, letting you treat from a safe distance. Dust-based insecticides applied with a bulb duster work well for nests inside wall voids, since the powder reaches deep into cavities.
Protective clothing matters. Hornet stings can puncture most single-layer fabrics, including bee suits, but they can’t reach skin through thick, baggy, or layered clothing. At minimum, wear long sleeves, long pants tucked into socks (or taped at the cuffs), closed-toe shoes, and chemical-resistant gloves. Eye protection and a mask are smart additions: goggles block venom that hornets can spray toward your face, and a mask prevents them from homing in on your breath. If you’re spraying overhead, flip the cuffs of your gloves outward so any dripping insecticide pools there and drains to the ground rather than running down your arm.
Should You Remove Them at All?
If the nest is in a tree at the edge of your yard, inside an unused outbuilding, or somewhere else that doesn’t create regular contact with people, there’s a good case for leaving it alone. The colony will die naturally in the fall, the nest won’t be reused, and in the meantime, those hornets are actively hunting yellowjackets and other pest insects around your property. For most Pennsylvania homeowners, European hornets are more helpful than harmful, as long as you’re not sharing a wall with them.