Yellow Jackets Swarm Corvallis

No jacket, but still a yellowjacket.

If you’ve seen more yellowjackets buzzing around in your backyard than usual, you’re not alone. Multiple news sources have confirmed a spike in the local yellowjacket population, which peaked this summer due to weather changes earlier in the year.

Unlike bumblebees, yellowjackets can sting a human multiple times and generally don’t die or lose their stinger during attacks. While bees play a part in every aspect of the ecosystem—using pollination to support the growth of plants—the role of yellowjackets and similar flying insects like wasps and hornets is different. Earlier this month, Corvallis’ KVAL News contacted a horticulturist at OSU, who explained that while yellowjackets are often seen as pests, “in typical scenarios they are beneficial insects, feeding on insects such as caterpillars that might otherwise damage your garden.”

The Advocate consulted a beekeeping expert, OSU Associate Professor of Apiculture Ramesh Sagili, to find out why there’s been an influx of yellowjackets to this area. The answer is related to Oregon’s current drought, but not to the summer heat.

“Reproduction of most insects, including yellowjackets, is dependent on weather,” says Sagili. Yellowjacket populations breed in the spring months, and this year’s spring was very dry. “We did not get much rain this year in the valley during March, April, and May,” he says. “During the years when spring is relatively mild and dry, yellowjacket populations increase rapidly, as they breed faster with multiple generations.”

The spike in the population has resulted in a turf war between humans and yellowjackets, because the more yellowjackets there are, the harder it is for them to find food and water. “This is the reason why you are seeing more yellowjackets in your backyard and other places,” adds Sagili.

Many local garden stores carry outdoor traps for yellowjackets which, while being more environmentally friendly than pesticides, still don’t get to the root of the problem, which is the yellowjackets’ nest. 

It’s possible to destroy the nests, but it’s important that we respect the environment while doing so. In another report released earlier this month by Fox 12 News, OSU entomologist Gail Langellotto advised using a “quick-acting, knockdown pesticide” for treating nests. The report adds that the University recommends using “the least toxic product first,” and to choose a product that says “caution” on the label rather than “danger.” And if you choose a pesticide-free method to destroy a nest, never use a method that’s illegal, like pouring petroleum products into nests in the ground.

By Kiki Genoa