Tooele City’s friendly red-and-black beetle residents have been a little too friendly this year, but experts say pesticides aren’t likely to solve the problem.
Boxelder bugs have built up in large numbers in Tooele this past summer, though it’s not entirely apparent why, said Linden Greenhalgh, Utah State University extension agent.
It’s possible that the extended warm weather has contributed to the situation, or that the bugs are simply on a natural cycle that caused a population boom this year, he said.
Greenhalgh said he’s run into a couple bad boxelder bug infestations this year — including one swarm that took over a shed in his own back yard. But he said the bugs are entirely harmless, and that there’s no reason to panic if boxelder bugs bring a few friends to your house this fall.
Boxelder bugs don’t bite, sting or eat human food sources, according to a fact sheet produced by USU. They congregate on walls of buildings as the weather changes in order to keep warm, and can occasionally gather in huge numbers.
Boxelder bugs may also wander inside houses to find a warm place to wait out the winter. However, they do not breed indoors and will not live long without access to their food source — the sap and juices of the boxelder tree.
Boxelder bugs lay their eggs at the base of boxelder trees twice during an average summer. The newly-hatched nymphs live on the trees while they mature, then move inside the tree or seek other forms of shelter to ride out the winter months.
When they do gather in numbers large enough to become a significant nuisance, Greenhalgh said the best way to control boxelder bugs is to spray the surface with water or with a solution of water and laundry detergent.
Boxelder bugs are resistant to most broad-spectrum pesticides, and those same pesticides can do significant harm to beneficial insects, like honey bees, Greenhalgh said.
“The thing to do would be to get rid of boxelder trees, but there’s so many of them around and they’re native, so that’s not really practical,” he said. “Wherever you have boxelder trees, you’ll have boxelder bugs.
“It’s a tough problem when there’s so many of them. It’s hard to deal with them,” he added.
Indoors, the best approach is to vacuum up the bugs and then dispose of the vacuum bag outside.
But for the most part, Greenhalgh said, it’s best to just ignore the harmless bugs and wait for the cold weather to send them back into their own homes.