Yellowjackets are social wasps that build colonies, often in the ground or inside walls, and they are drawn to sugary food and garbage. The University of California publishes a Pest Note on them. Do not disturb a nest yourself, keep people and pets clear of it and ask a technician to remove it when it is near living space.
Key takeaways
- Yellowjackets are social wasps that live in colonies, and the colony grows through the warm months.
- Nests are often in the ground, in wall voids or under eaves, so a nest can be closer than it looks.
- Sugary drinks, ripe fruit, pet food and open garbage draw yellowjackets to the places people use.
- A nest near a door, play area or a path is a job to schedule with a technician, not to attack yourself.
- A sting can cause a serious reaction in some people, so anyone with a known allergy needs a plan before a nest is found.
Are yellowjackets the same as other wasps?
Yellowjackets are social wasps with a black-and-yellow pattern and smooth, slim bodies. Other wasps look different and behave differently, so identification matters before any nest is treated.
Yellowjackets are a group of social wasps. They build colonies with a queen, workers and, later in the season, reproductive wasps, and the colony can grow to a large size by late summer. Their bodies are generally smooth and slim, with bright bands of black and yellow. That is a useful clue, but several other wasps look similar, and a careful identification is the safest step.
Paper wasps are more open-bodied and build exposed combs, often under eaves or on the undersides of structures. They are less likely to nest in the ground or inside wall voids. Their behavior differs as well, and a technician will treat a paper wasp nest differently from a yellowjacket nest.
The University of California's Integrated Pest Management Program has a Pest Note on yellowjackets and social wasps. It describes the general biology and the habits of these insects, and it is the right reference for the broad picture. A nest should be identified before it is disturbed, and a photograph is a good first step if you are unsure.
Where do yellowjacket nests usually sit?
Yellowjacket nests are often in the ground, in wall voids, under eaves and in other sheltered spaces. Because many nests are hidden, a colony can be closer to the house than the visible activity suggests.
Some yellowjacket species nest in the ground, often in an abandoned burrow or a space under a lawn edge, a shrub or a stone. Others build in cavities such as wall voids, attic spaces, hollow trees or under decking. The entrance may be a small hole that looks like nothing more than a gap in the soil or in the siding.
The first sign is usually activity. Wasps flying in and out of one spot, especially along a line, point to a nest close by. A steady stream of wasps around a single entry point is worth checking carefully. Do not walk up to the spot to look, because disturbing the entrance is the most common way people are stung.
Rural homes have more hiding places than many urban ones. Woodpiles, sheds, fence lines and overgrown margins give wasps and their nests places to sit unseen. A regular walk around the house, looking at the eaves and the ground along the edges, is a sensible habit.
Why do yellowjackets come to food and garbage?
Yellowjackets are drawn to sugar and protein, which they find in drinks, ripe fruit, pet food, meat scraps and open garbage. Keeping those things covered and away from eating areas reduces the attraction, although it will not remove a nest already present.
Workers forage for food to feed the colony. Sugary drinks and fallen fruit draw them in during late summer, and protein sources such as meat and pet food draw them in at other times. A backyard meal can attract a steady stream of wasps, and a soda left on a table is an easy target.
Garbage is one of the most common attractions around a house. An open can, a bag left out overnight or a compost pile without a lid can keep wasps coming back. Seal the containers, rinse recyclables before they are stored and keep pet food indoors where possible. These habits will not remove an established nest, but they lower the number of wasps that visit the house.
Keep an eye on the places where food is prepared outdoors. A grill, a fruit tree or a bird feeder can all become a feeding point, and moving the activity away from the living space is often enough to reduce the problem.
What should I do if I find a nest?
Leave the nest alone, keep people and pets away from the spot and note where the activity comes from. A nest close to living space is a job for a technician, who can identify it and remove it safely.
The first rule is not to disturb the nest. Wasps defend a colony, and a person who bumps, sprays or pokes at a nest can be stung many times. Keep children and pets well away from the area, and avoid mowing, digging or using a leaf blower close to the entrance until the nest has been dealt with.
Mark the location in your mind or with a stake, and note the time of day when activity is highest. Yellowjackets are most active during the day, and their numbers can change through the season. Give that information to the technician, because it helps them plan the removal.
Do not try to remove a nest with a household spray in the open, and do not wrap a nest in a bag to shake it off. Those methods are a common cause of stings. If a nest is in a wall, under a deck or in the ground by a path, the safest option is a technician who is trained to deal with it.
When is nest removal a job for a technician?
Removal is a technician's job when a nest is near a door, a path, a play area or a living space, when it is in a wall or the ground, or when anyone in the household is at risk of a serious sting reaction.
A nest in the open, far from the house and away from paths, may be left alone for the season if it is not causing a problem. A nest that is inside a wall, under a deck, in a shed or in the ground near a path is a different job. Those locations make it hard to see the nest and easy to disturb it by accident.
A technician will identify the species, look at the nest location and choose a method that suits it. Ask how they will approach the nest, whether the work is done at night when wasps are less active and whether the nest will be checked after removal. Removal is not always a single visit, and the quote should say so.
Local nest timing is not documented on this site, so this guide does not say when a nest in Anderson Valley is most likely to be found. The safe rule is to act when a nest is found near living space, whatever the month.
What about stings and allergic reactions?
Most stings cause pain and swelling that fades, but some people react strongly. Anyone with a known allergy, or who has had a bad reaction before, needs a medical plan, and a severe reaction needs emergency care without delay.
A sting usually causes sharp pain, redness and swelling at the site. Most of those symptoms settle in a few days. A person who is stung several times, or who is stung in the mouth or throat, can have a more serious reaction, and any trouble breathing, swelling of the face or throat, or dizziness is an emergency.
Anyone who has had a severe reaction to a sting before should carry the medication their doctor has prescribed and should tell the people they live with where it is kept. Ask a medical provider for a plan before a nest is removed, because the removal is the moment most stings happen.
Keep the number for emergency services with you when working outdoors near a nest. A technician can explain the removal in advance, and a household with a known allergy should say so when the job is booked, so the work can be planned around it.
What can households do to make the house less attractive?
Keep food and drink covered outdoors, seal garbage containers, clear fallen fruit, store pet food indoors and check the eaves and ground around the house for early nests. These steps lower the attraction, but they do not replace removal of an established nest.
Start with the things people bring outdoors. Cover food and drink, clear the plates after a meal and keep the lids on garbage and recycling bins. Pick up fallen fruit from the ground around fruit trees, because it attracts wasps quickly and it keeps them near the house.
Look at the house once a season. Check the eaves, the soffits, the gaps around pipes and vents, and the ground along the foundation and the lawn edges. Early in the season, a nest is small and easier to deal with. Late in the season, a colony can be large and noisy, so finding it early is the best way to keep the problem manageable.
Finally, plan outdoor work around the season. A yard task close to a known nest, or a meal served next to a bin, can turn a quiet afternoon into a problem. Calling (855) 974-4733 is the quickest way to get a nest identified and removed when one is close to your living space.
Frequently asked questions
Are yellowjackets aggressive?
They defend their nest when it is disturbed, and they can sting more than once. Most of the trouble happens when someone walks close to an entrance, mows over a ground nest or knocks a nest in a wall. Leave the nest alone and keep people and pets clear.
Can I remove a yellowjacket nest myself?
It is not recommended. Nests in walls, under decks or in the ground are hard to see and easy to disturb, and the stings are the most common result of a home attempt. A technician can identify the nest and choose a safe method.
What should I do if someone is stung and has an allergy?
Follow the emergency plan the person's doctor has set out, and call emergency services for any trouble breathing, swelling of the face or throat, or dizziness. Do not wait to see whether the symptoms pass in a serious case.
Will removing food from the yard stop the wasps?
It reduces the number of wasps that visit, but it will not remove a nest that is already present. Covering food and sealing garbage help most when combined with a technician's removal of any nest close to the house.
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This guide is general information for Mendocino County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.