Boxelder bugs

Box elder bugs can congregate on the side of buildings by the thousands.

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The colors most associated with Halloween are orange and black, so it seems appropriate that a type of insect known to invade homes and terrify some people this time of year shares those colors.

We’re talking about box elder bugs — those flat, oval-shaped insects that amass zombie-like on the sunny side of buildings and homes when the weather cools each autumn, some eventually making it inside.

The 2020 box elder bug invasion is just beginning in Cache Valley and should reach its peak over the next 30 days.

Entomologists say the horror these members of the “true bug” family cause some people is really unnecessary. As insects go, box elder bugs are about as harmless they come. They don’t bite, they don’t damage structures and they don’t even harm the trees they most commonly live in and feed upon, which are fittingly known as box elder trees.

“Box elder bugs can’t really bite humans and they don’t have any desire to,” said Utah State University insect specialist Zach Schumm, explaining that instead of what we would call teeth, the bugs have a proboscus or “stylet mouth” that they stick into their food to suck out the juices or nutrients. “They could technically poke you with their mouth part, but they aren’t at all aggressive.”

Schumm said the reason box elder bugs clump together on walls and windows every fall is twofold: They emerge from lawns, plants and trees to keep warm while also looking for places to ride out the winter.

“Insects are ectotherms, meaning they get all their body heat from the sun. When it’s cold outside, they need to get their heat from somewhere, and the best way to do that is just to sun themselves on surfaces,” he said. “The ones you see sunning themselves will find overwintering sites either within homes or any protected structure … then come out next spring to lay eggs on trees.”

Schumm said the USU Extension fields a lot of questions about how to eradicate box elder bugs, but he recommends against it since “there’s a chance you can do more harm than good.” Instead, he advises local residents to just do their best to seal up their houses and keep the pests out.

Look online and you’ll find several folk remedies for keeping box elder bugs off your house. Soapy water is one bug-repellent that has gained popularity in Cache Valley, but critics say it only works for a short period of time after application to a surface. Another touted repellent is water mixed with cayenne pepper, sprayed directly on the insects.

Does Cache Valley have more of these bugs than other parts of the country? After all, the county directly to our west is named Box Elder.

Schumm said there may indeed be more of the bugs in these parts due to the abundance of their namesake trees, but the little black-and-orange insects are found virtually all over the United States.

Box elder bugs have inspired a book of poetry, “The Boxelder Bug Variations” by Minnesota writer Bill Holm. Among Holm’s verses is a prayer to the insects, which reads:

I want so little / For so little time / A south window, / A wall to climb, / The smell of coffee, / A radio knob, / Nothing to eat, / Nothing to rob, / Not love, not power, / Not even a penny, / Forgive me only / For being so many.

Perhaps more worrisome home intruders than box elder bugs each fall are spiders, but Schumm — who carries the official USU title of “arthropod diagnostician and urban integrated pest management associate” — said arachnids shouldn’t cause locals too much concern either.

“We don’t really have a lot of insects or spiders that are harmful to humans in the state of Utah in general, let alone here in Cache Valley. Other than the black widow spider, there’s really nothing that’s considerably impactful to human health, and we don’t really see many black widows in Cache Valley,” he said.

Schumm, who happens to keep a “pet” black widow on his office desk, said deadly brown recluse spiders are not found this far north in Utah unless transported by accident in shipping crates and the like. He also plays down the common fears about hobo spiders, which are found in this area.

“We hear about the hobo spider in Utah, but there’s not a lot of evidence that shows the venom itself actually harms the human body,” he said. “A lot of times the issues that come from spider bites are because of improper wound treatment and because bites can become infected, but it’s not necessarily due to the bite itself.”

Charlie McCollum is the managing editor of The Herald Journal. He can be reached at or 435-792-7220.

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