You aren’t imagining it: Pest control businesses in Spokane report significantly higher yellowjacket activity this year

If you have noticed an uptick in the number of yellowjackets buzzing into your backyard barbeques and picnics in the park this summer, you aren’t alone.

This August was the worst for yellowjackets that Elmer Bensinger, COO of Eden Advanced Pest Technologies, has seen in his nearly 30 years in the industry.

More than 90% of the calls that the local company has received since June have been related to yellowjackets, Bensinger said, noting that September is usually the busy season for the insects.

Karen Dawes, co-owner of Spokane Pest Pro, has had a similar experience. Having run her pest control business for more than 10 years, most of her observations are anecdotal.

“Yellowjackets have been a bigger issue in Spokane than I think I’ve seen in the last five to 10 years,” she said. “We have got a ton of calls with just general nuisance airspace activity, like, ‘Oh, I don’t see a nest, but dang it, there’s hundreds out and they are chasing me in my house.’ ”

One customer even greeted her at the door in a bee suit due to the huge quantity of the insects.

In a typical year, yellowjacket numbers start off low in the spring as mated females that survived the winter begin their colonies from scratch, said Elizabeth Murray, Washington State University expert in wasps, bees and ants. The colony numbers grow throughout the summer as the first generations are able to scavenge more food for the next. The highest colony numbers occur in the late summer, and then populations decline as food and warmth disappear for the winter.

Yellowjackets are opportunistic wasps, so when the insect populations that they prey on begin to decline in the fall, humans eating dinner outside or throwing out their leftovers can be a game-changing source of food, Murray said.

The wasp’s desperation for food can lead to attacks as well, said Gary Chang, an entomologist at Gonzaga University.

“They’re really not too picky if they’re biting into a hot dog or biting into your forearm,” Chang said. “And, if you happen to, you know, brush them away, they also aren’t reluctant to sting.”

But this year, phone calls to Bensinger’s and Dawes’ pest control businesses about yellowjackets have been unusually high. Both share the same suspicion as to why: the weather.

“It does seem to point to the fact that we had a pretty mild winter in Spokane,” Dawes said. “And with that mild winter and then the sudden explosion of heat when summer finally did arrive – it’s like our overwintering wasps actually didn’t all die off and everything hatched and reproduced at once.”

Murray said a greater number of overwintering wasps could lead to more established colonies, although the true reason for large amounts of yellowjackets remains speculative. Chang said that the undesirability of yellowjackets along with their underground nesting habits has made their yearly habits difficult to study.

“It’s just tough to find nests in the ground, and most people, if they do find a nest, they want to get rid of it as soon as possible,” Chang said. “It might continue to be kind of unknown and unclear what’s going on with the big yellowjacket years.”

Dawes said that in addition to regular pest control, it is important to limit standing water on hot days to prevent wasps coming to drink. Ensuring there are no aphids nearby – insects that Dawes describes as “like snow-cones” to hungry yellowjackets – and hanging wasp traps away from where people congregate are other management strategies.

Nothing but time will completely eliminate the unwelcome visitors, though, she said.

“Circle of life – it’s nature. Let’s be patient,” Dawes said. “I know that sounds like such a bummer, like such a nondefinite solution. But unfortunately, there is just not a real solution when they’re this numerous.”