Boxelder bugs become a nuisance in homes, especially when you’ve boxelder, maple, and ash trees on your property.
These bugs enter homes in droves and end up in places where you least expect them to be.
The worst part is that boxelder bugs can bite despite being harmless.
The good news is that it’s easy to eliminate boxelder bugs.
In this guide, I’ll share what kills boxelder bugs and how I used a mix of natural remedies and chemicals to eliminate them.
Let’s dive right in.
Boxelder Bugs – Identification
Boxelder bugs are flat, oval-shaped black bugs with orange markings on their backs. They’ve got six legs and a pair of antennae. They’re 0.5 inches in size when they’re fully grown adults.
Boxelder bugs also have a pair of fully developed wings that help them to fly a mile or two.
Boxelder bugs are true bugs. True bugs are a family of bugs to which bugs like stink bugs and kissing bugs.
Belonging to the family of true bugs also means that they have robust mouth parts that they can use to puncture their food source.
Their mouths are visible as a stubby beak right on the tip of their heads.
Boxelder Bugs Habitat: Where Do They Live?
Boxelder bugs live on trees like boxelder, maple, and ash. If these trees are in your yard, you will have a boxelder bug problem.
Boxelder bugs are widespread in regions with boxelder trees.
So, the eastern US, the northern border touching Canada, Arizona, and the colder regions of the US face the brunt of boxelder bugs during the fall and winter months.
Boxelder bugs feed on the seeds of female boxelder trees. Tree leaves, plant sap, and fruits like apples and plums also contribute to boxelder bugs’ diet.
Too many boxelder bugs in the trees will cause significant harm to the trees. And given their lifecycle, boxelder bugs can indeed reproduce fast.
Boxelder Bugs Lifecycle
The lifecycle of boxelder bugs begins when the females lay their eggs on the undersides of the leaves and in the crevices of tree bark.
A female boxelder bug can lay 200-300 eggs in her lifetime. She lays the eggs in clusters in different egg-laying sites during the spring and summer.
The eggs hatch within 10-14 days, which leads to nymphs. The nymphs are 1/16 inches in size, bright red, with black wing pads that are visible.
The eggs hatch in late spring and early summer. That’s why homeowners notice a sudden appearance of bright red oval-shaped bugs if they’ve trees like boxelder trees on their property during this period.
The boxelder nymphs are equally active as the adults. They suck out the tree saps and feed on the fruits and newly grown leaves.
The boxelder bugs’ nymphs will molt five times throughout the summer before they turn into adult boxelder bugs.
These newly formed adult boxelder bugs breed, laying eggs again, leading to a second generation of boxelder bugs.
Adult boxelder bugs and their nymphs enter homes, sheds, basements, and garages in late fall and early winter, looking for a warm place to overwinter.
The nymphs will mature into adults during the overwintering period. These overwintering insects will emerge as adults when spring arrives.
They’ll lay eggs in the spring, and many die after laying their eggs. So, the entire lifecycle of boxelder bugs can last for a year.
How Boxelder Bugs Enter Homes?
Any thin crevice on the windows, doors, and walls can be entry points for boxelder bugs. Thanks to their flat body shape, they can also slide through the gaps in the garage doors, basement vents, and any other gap that leads to a warm place inside the house.
Before entering the house, boxelder bugs will gather on the sunny side of the house. East and west-facing homes have boxelder bugs piling on the windowsills or patio decks because these regions receive direct sunlight.
You can also accidentally bring boxelder bugs inside the house if you introduce plant pots or any wooden block with these insects.
Once inside the house, boxelder bugs will gather in any place randomly. However, they’re looking for wall crevices, clutter, and areas with fewer human footfalls to hide.
Damages Boxelder Bugs Cause
Boxelder bugs can cause significant damage to maple, ash, and boxelder trees. They’re a real threat to apple and plum orchards as well.
However, boxelder bugs don’t cause any structural damage inside the house. They don’t feed on anything or bore into furniture or floor.
But boxelder bugs defecate a reddish liquid, which can cause some stench. The worst part is that they can leave their fecal matter on floors, walls, and places like beds, couches, curtains, and drapes.
The reddish stain of their feces is tough to remove.
They can also get inside stored food containers inside the kitchen and leave their fecal deposits on the stored foods behind.
Apart from defecating, boxelder bugs also urinate. Their urine smells attract other boxelder bugs, causing them to congregate in one area.
Do Boxelder Bugs Bite?
Boxelder bugs don’t seek out humans or pets to bite. However, their sharp mouthparts can land a mosquito-like bite if you try to handle them.
A boxelder bug on my bed got pressed against my skin while I was asleep. It caused the bug to bite me on my arm, which led to a mosquito bite-like wound on my skin.
But boxelder bug bite is harmless and doesn’t have any side effects apart from a bit of itching.
Natural Remedies That Kill Boxelder Bugs Indoors
You can eliminate boxelder bugs in the house without breaking a sweat. And you can do it by using a mix of natural remedies and chemical sprays.
I used white vinegar and soapy water spray to kill the boxelder bugs in the house. I followed it up using a vacuum cleaner to remove the dead boxelder bugs.
Here’s how I did it.
Your vacuum cleaner is the most straightforward, no-brainer way to eliminate boxelder bugs in the house.
Use the cleaner to scoop them off the surfaces where you find them in large numbers.
But remember to dispose of the vacuum dust bag properly outside your property. Else, the bugs can come back.
However, remember that the vacuum cleaner won’t kill the boxelder bugs.
White Vinegar Spray
I made a homemade boxelder bug spray by mixing equal parts of white vinegar and water.
I poured the mixture in a handheld pump spray bottle and used it on the boxelder bugs. The acidic nature of white vinegar was potent enough to kill the boxelder bugs.
I also sprayed the mixture on the areas where boxelder bugs gathered inside the house. It removed the smell of their urine from those areas.
Removing the urine smell was essential. Otherwise, it’ll attract more boxelder bugs inside the house.
Soapy Water Spray
If you don’t like the acidic smell of white vinegar, then you’ve another option – soapy water.
Fill the pump spray bottle with water and pour two tablespoons of liquid dish soap. Shake the bottle well and spray the mixture on the boxelder bugs.
The sulfate in the dish soap melts the exoskeleton of boxelder and enters their bodies. The soap then absorbs their fats and moisture, which triggers the bugs’ death by dehydration.
Do not forget to remove the dead boxelder bugs with the help of a vacuum cleaner. Also, clean the areas where you’ve found the boxelder bugs to remove their urine smell.
The third is horticultural oils. These are the most non-toxic on the list and harmless to beneficial insects.
And the best part is that you can use them throughout the year to keep bugs away.
You can use the horticultural oils from the bottle on the boxelder bugs to kill them.
But there’s one drawback. Its effects are short-lived. So, you’ll have to use it once every couple of days to eliminate boxelder bugs, especially when they’re too many.
As a preventive measure, you can also spray the oils on the places where boxelder bugs hide.
Scatter diatomaceous earth on the boxelder bugs. Diatomaceous earth is a desiccant that absorbs moisture and oils locked underneath the bugs’ exoskeleton.
Diatomaceous earth has diatoms, a type of fossilized remains of microalgae or plankton. These diatoms cut through the shells of the bugs and penetrate their bodies.
Like most non-toxic ways, diatomaceous earth is not an instant bug killer. It’ll take 2-3 hours to work. But wear a dust mask while scattering it.
How To Kill Boxelder Bugs Outdoors With Chemical Sprays?
You can use chemical sprays to kill boxelder bugs in the spring and summer months to prevent them from entering your home.
And there are specific chemical sprays that do the job exceedingly well.
One of them is a Spectracide Triazicide chemical spray. It’s one of the best boxelder bug killers you can use on nymphs and adults to kill them instantly.
Another option is pyrethrin-based sprays. Pyrethrin-based sprays work equally well to kill boxelder bugs in all their lifecycle stages.
It means they can also destroy the boxelder bugs’ eggs and prevent them from hatching.
Bifenthrin-based insecticide concentrates are also potent boxelder bug killers.
Mixing the concentrate with water and spraying it on the boxelder bugs has a massive impact on eliminating these nuisance pests.
It’s always best to use the sprays in a way that they make complete contact with the bugs.
However, you should also ensure that you use these sprays in the gaps on the walls, windows, and doors to kill any hiding boxelder bugs.
There’s always an element of risk involved while using chemical insecticide sprays because they’re toxic.
Always read the instructions and take appropriate safety measures while using these sprays.
And keep them out of the reach of children and pets.
I don’t recommend using these sprays indoors to kill boxelder bugs for safety reasons, especially when you’ve pets, the elderly, and little kids living in the house.
How To Prevent Boxelder Bugs From Entering Your House?
If there are pathways for boxelder bugs to invade your home, they will. The trick to prevent boxelder bugs from entering the house is to close their paths and use repellents.
Here’s how you can do it.
Refrain from Growing Female Seed-Bearing Boxelder Trees
The female boxelder trees contain seed pods that boxelder bugs eat. These trees play a significant role in attracting these bugs.
So, I suggest you refrain from growing female boxelder trees on your property.
Caulk Gaps and Cracks
The gaps and cracks on the windowsills, walls, doors, porches, roofs, eaves, and crawlspaces are entry points for boxelder bugs and many home-damaging pests.
Seal cracks with a silicone-based sealant. Silicone-based sealants are sturdy and waterproof; bugs can’t chew through them.
Use door sweeps and weather strips to close the gaps in the doors and window frames.
Use Repellents Where Boxelder Bugs Gather
Borax, diatomaceous earth, insecticide dust, and horticultural oils are not just boxelder bug killers but also repellents.
Use them on the windowsills, doorsteps, patio decks, and in places like the garage, attic, and basement to keep boxelder bugs away.
You can also use a peppermint oil spray on these areas. Most insects, including boxelder bugs, hate the scent of peppermint and keep away from places that smell minty.
Spray a Strong Squirt of Water with a Garden Hose
Whenever you see large numbers of boxelder bugs on windows or elsewhere, use your garden hose to spray intense water on them.
It’s good enough to disperse and keep them away from your home.
Maintain Cleanliness in Your Yard
Organic debris such as leaf litter, rotting wood piles, and decaying mulch beds are magnets for bugs.
Add excessive moisture to them, giving you a perfect habitat for boxelder bugs.
So, keep your yard clean. Don’t let waste pile up in the yard and the garbage bins.
Hire Professional Pest Control
During some seasons, the boxelder bug infestation is quite severe. And despite your best efforts, you might still need to eliminate them.
In that case, I highly recommend hiring an expert pest controller to get rid of these bugs.
Professional help is always necessary when dealing with a massive insect breakout.
Summary of What Kills Boxelder Bugs
Vinegar spray, soapy water spray, horticultural oils, diatomaceous earth, and borax kill boxelder bugs.
Chemical sprays such as spectracide triazicide, pyrethrin-based sprays, and bifenthrin-based sprays kill boxelder bugs instantly.
As these chemicals are toxic, it’s always best to use them outdoors to control boxelder bugs. For indoors, use natural methods laid out in this post.
Nang Chen is an Entomologist and Arachnologist who is associated with Vienna’s museum of natural history. He’s also a consultant with real estate groups, insecticide conglomerates and law enforcement groups as a forensic entomologist. Nang Chen holds an M.S. from South China University and he’s a regular contributor to our site.