One way to identify yellowjackets is by their black antennae. (Katja Schulz/Wikimedia Commons)
Yellowjacket nests are made from a papery substance produced by the yellowjackets. (Courtesy of Wikimedia Commons)
Yellowjackets are shinier than honeybees and have yellow and black markings all over their bodies. (Photo by Kathy Keatley Garvey)
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One way to identify yellowjackets is by their black antennae. (Katja Schulz/Wikimedia Commons)
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Ah, summertime in Marin! Long, sunny days, backyard barbecues and, unfortunately, those uninvited guests at the picnic table: yellowjackets. These striped speedsters seem to have an uncanny knack for sniffing out your sandwich and making a beeline for your lemonade. But before you reach for the swatter, let’s take a step back and consider the bigger picture. Yellowjackets aren’t just party crashers — they’re also hardworking members of our local ecosystem.
Yellowjackets (Vespula spp.) are often mistaken for honeybees, but they’re actually wasps, and they play an important role in nature. As predators, they help keep populations of garden pests like caterpillars and aphids in check. And while they’re not as famous for pollination as bees, they do contribute by feeding on nectar and transferring pollen as they zip from flower to flower.
That said, no one wants a yellowjacket nest under the deck or an aggressive swarm near the picnic table. Unlike honeybees, which die after stinging, yellowjackets can sting multiple times, making them a painful problem when they set up shop too close for comfort. Fortunately, there are ways to manage these feisty fliers while still respecting their ecological role.
Keep yellowjackets from moving in
The best way to deal with yellowjackets is to keep them from settling in your yard in the first place. Here are a few Earth-friendly strategies recommended by the University of California Statewide Integrated Pest Management Program (UC IPM):
• Seal up food sources. Yellowjackets are scavengers, so keep trash cans tightly sealed and promptly clean up food scraps from outdoor meals.
• Limit sugary drinks. Open soda cans and juice boxes are like yellowjacket magnets. Use cups with lids and straws to cut down on their attraction.
• Check for early nests. In spring, queens start new colonies. Look under eaves, in tree hollows and around wood piles for small golf-ball-sized nests, which can often be removed safely before they grow. A common location for yellowjacket nests is underground, often in abandoned rodent burrows or other cavities. These are harder to find.
• Use yellowjacket traps wisely. Traps can help reduce numbers but won’t eliminate a colony. If using them, place them away from eating areas to draw wasps elsewhere.
When you have a nest problem
If yellowjackets have already built a nest in a high-traffic area, removal may be necessary — but it’s not a DIY job! These insects defend their nests aggressively, and disturbing them can result in multiple stings. That’s where the Marin/Sonoma Mosquito and Vector Control District comes in. This free public service will assess and remove yellowjacket nests on residential properties, keeping you and your neighbors safe without harming the environment.
Natural alternatives
Manage yellowjackets organically. Here are some safe methods:
• Soapy water spray. A simple mix of dish soap and water can be an effective way to neutralize a small aerial nest when applied at dusk or dawn, but proceed with caution.
• Meat traps and sugar traps. Yellowjackets undergo a dietary shift as summer transitions to fall. In the early months, they hunt protein — such as insects and meat — to feed their developing larvae. However, as the colony matures and fewer larvae need feeding, adult yellowjackets pivot to a sugar-rich diet, seeking out ripe fruit, nectar and even your soda can. A well-placed trap baited with fish or meat earlier in the summer, and then with a sugary lure in late summer, can help manage their numbers effectively.
• Keep compost bins covered. Rotting food attracts yellowjackets, so ensure your compost bin is secured.
Coexisting with nature
At the end of the day, yellowjackets are just trying to do their job in the grand scheme of the garden. They may be a nuisance at times, but they also help maintain balance in our local ecosystem. By taking simple preventative measures, using environmentally friendly control methods and calling in expert help when needed, we can all enjoy our summer gardens — without too many uninvited guests buzzing around our burgers.
For more information on yellowjacket management, check out UC IPM’s website at ipm.ucanr.edu or contact the Marin/Sonoma Mosquito and Vector Control District for assistance. Go to msmosquito.org.
Sponsored by UC Cooperative Extension, the University of California Marin Master Gardeners provides science- and research-based information for Marin home gardeners. Email questions to helpdesk@marinmg.org. Attach photos for inquiries about plant pests or diseases. Please call 415-473-4910 to see when a master gardener will be at the office or drop off samples 24/7 in the sample box outside the office. To attend a gardening workshop or subscribe to Leaflet, a free quarterly e-newsletter, go to marinmg.ucanr.edu.
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