Useful Tips and Free Help from the Mosquito and Vector Control District
One of the many services our District provides is the control of in-ground yellowjacket nests. This year they have responded to over 4,131 calls for nest eradication- a nearly 165% increase from last year at the same time!
Although there are a record number of calls for service, many residents are still having issues with yellowjackets on their property because they can’t seem to find the nest.
Yellowjackets often make their nests underground in abandoned gopher holes, but are also known to nest in wood piles, dense vegetation, utility vaults, and other enclosed spaces. They look for food close to their nests, usually staying within 1,000 feet of them. They are most active between 10 a.m. and 4 p.m., though activity slows in extreme heat or cold.
- To find a nest, begin by searching your property looking for yellowjackets flying in and out of holes (often along a constant “bee line”) or a cluster of yellowjackets “guarding” an opening.
Even if you find one nest, keep searching in widening circles, as multiple nests may be present. - Step carefully as vibrations can trigger aggression from underground colonies. Click here for a more detailed description on how to find a nest.
- Once you find the underground nest, mark it so that it can be easily re-found by a technician, and call our office at 707-285-2200 or submit a service request online.
- Remember, Vector Control only treats underground yellowjacket nests and they do it for free! If you find a structural nest (one that is attached to a structure or in the wall of a structure) contact your local pest control operator.
Yellowjackets can become extremely aggressive when you approach their nest, so be extra cautious when placing the marker. You do not have to place the marker next to the nest—it can be placed in the general vicinity as long as we have clear instructions on the location. The most important thing is to not place anything in or on top of the nest.
Who’s Nesting in the Ground? Yellowjackets vs. Paper Wasps
Many people confuse yellowjackets and paper wasps, especially when it comes to identifying their nests. Here’s how to tell them apart and what to do if you find one.
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European Paper Wasps: The New Neighbors European paper wasps are a newer arrival in California and are becoming more common. They typically build small, open-air nests under eaves, in shrubs, or tucked into other sheltered spots. However, unlike native paper wasps, they will also nest in cavities—such as pipes, gates, or vents. These wasps will defend their nests, but they are usually less aggressive than yellowjackets unless threatened. European paper wasps may actually help control garden pests because they feed on other insects. But if their nest is in a high-traffic area or if you’re allergic to stings, you may want it removed. The District does not remove paper wasp nests. If needed, homeowners can contact a licensed pest control company for assistance. |
Western Yellowjackets: The Underground Aggressors Western yellowjackets are a common sight during summer and fall—and they can be aggressive. These wasps often build large, hidden nests underground, especially in abandoned rodent burrows. Western yellowjackets are active hunters. They eat slugs, grasshoppers, flies, spiders, and other insects, but they’re also scavengers and will go after meat or sweet foods—especially at picnics or barbecues. If their underground nest is disturbed, they will defend it—sometimes in large numbers. |
One way you can tell the difference between these wasps, is by the way they look when they fly. The European paper wasp has long dangling legs, while the yellowjacket flies with its legs tucked in.
“It’s a yellowjacket when the legs are tucked back-it!”
Another way to tell the difference between a paper wasp and a yellowjacket is by placing a piece of meat outside. The yellowjacket will take a piece of meat back to the nest, while the paper wasp will fly right by it.
Visit the Vector Control website to learn more about yellowjackets and ways to protect yourself from being stung.
The Marin/Sonoma Mosquito and Vector Control District’s programs and services are funded through property taxes and benefit assessments, and are provided to all residents in Marin and Sonoma counties at no additional cost.