July 2020- One of the most commonly asked questions we receive this time of year is, “How do I locate an underground yellowjacket nest?” Locating underground yellowjacket nests can be a challenge that requires time and lots of patience, but it can be done.
Yellowjackets often make their nests underground in abandoned gopher holes, but are also known to nest in wood piles, dense vegetation (like Italian cypress and ivy), utility vaults, and other enclosed spaces.
Most importantly, yellowjackets look for food close to their nest— usually within 1,000 feet—so you won’t have to look far for a nest, unless it happens to be located on an adjacent property. In that case, you may need to enlist the help of your neighbors on your yellowjacket hunting quest.
Keep in mind that yellowjackets can be quite aggressive and have been known to cause great harm to those that are allergic to their stings. If you are highly allergic to stings, we recommend not searching for the nest yourself.
Yellowjackets are most active between 10 am and 4 pm, weather dependent. If the weather is too cold or too hot, yellowjacket activity will be a little sluggish. We suggest you begin your search in the morning—usually after 10 am—when the weather is beginning to warm and the yellowjackets are actively flying in and out of their nest. Sometimes the late afternoon sun can work in your favor, increasing your ability to see their direct route to the nest.
Begin by searching the ground around your home for holes, walking in a circular pattern around your property, and expanding your search area with each pass. Watch for yellowjackets flying in and out (often along a constant "bee line") or a cluster of yellowjackets "guarding" an opening. If you are lucky enough to find an active nest on your first go-round, don't stop there, continue checking the rest of your property as there may be more nests. Be careful where you step and be aware that the vibrations from your footsteps may agitate underground colonies causing them to become defensive and aggressive.
If this method does not work, you can try to locate the nest by placing a piece of meat on the ground and waiting for a yellowjacket to take a piece. Yellowjackets do not eat the meat themselves, but take it back to their nest to feed the larvae (young yellowjackets). Once a yellowjacket picks up a piece of meat, your job is to follow it back to its nest. This method can be time-consuming and requires patience because yellowjackets don't always fly in a straight line back to their nest, but will be well worth the time and energy if you do find the nest.
Once you have located the underground nest, mark it so that it can be re-found easily by one of our technicians. DO NOT place the marker directly on or in the nest as it could easily agitate the yellowjackets. After marking the nest, call our office at 707-285-2200 or submit a service request online at www.msmosquito.org.
The Marin/Sonoma Mosquito and Vector Control District is funded through property taxes and benefit assessments so there is no additional charge for any of our services, including underground yellowjacket nest control.
Please keep in mind that we do not control aerial yellowjacket nests, paper wasp nests, or any other type of nest that is attached to a structure. For yellowjacket nests attached to a structure, we recommend contacting a local pest control company.