What to Know About Boxelder Bugs

Medically Reviewed by Mahammad Juber, MD on April 10, 2022
5 min read

Boxelder bugs are more of a nuisance than a problematic insect. They’re related to stink bugs and cicadas.  

The main reason that they can become pests is their tendency to surround and enter your home in large numbers. Luckily, when they’re at an active stage in their lifecycle, they won’t survive in your house for more than a few days. 

The boxelder bug is a relatively harmless insect that’s named after its main food source — the box elder tree. They feed off of the female versions of these trees — which are the only ones that produce seed pods. They also occasionally feed off of the male box elder trees and maple, ash, and fruit trees when they need to. 

They have mouth parts that can pierce these trees and reach their food — the tree’s sap. They also eat seed pods from the female box elder tree.   

Their life cycle includes a dormancy stage during cold weather. They won’t move or disturb your home in any way during cold months of the year.

You want to make sure that you’re not confusing boxelder bugs with a similar insect. Make sure that you know what they look like so you can positively identify them in and around your house. 

There are three stages in the boxelder bug life cycle — egg, nymph, and adult. They also look different at different developmental stages, and you’re most likely familiar with the adult stage of the life cycle. 

Adults have red abdomens that are covered up by long, black wings. These wings bud from the top of the torso — closer to the head. The wings expand to slowly cover up the entire torso until the insect is mostly black with a few reddish-orange lines. When folded, their wings look like an “X” on their backs.

The wings are functional — adults can fly for a few miles at a time — but you’re more likely to spot them huddled in a crevice or pressed against a wall. 

The nymphs are smaller and almost entirely red, their torsos are uncovered. You’re much less likely to encounter the bugs at this stage.  

They’re shaped like long ovals and have six legs. Two antennae protrude from their small heads. 

Full-grown, they’re around one-half of an inch long, whereas young nymphs are around one-sixteenth of an inch.

Boxelder eggs are reddish ovals that are very small. They can be found in clusters on box elder trees in the spring.

You may confuse the adult boxelder bugs with beetles or milkweed bugs, but beetles have wings that make a straight line when they come together — they don’t cross in an “X.” Milkweed bugs, meanwhile, have similar color patterns and body plans but are a brighter red.  

In general, boxelder bugs won’t cause any harm to you, your pets, or your plants. They don’t transmit any diseases. They don't even like human food and will leave your supplies alone. 

Do boxelder bugs bite? Boxelder bugs rarely bite. There are very few reported situations where they have bitten someone. Moreover, it’s always an act of self-defense and won’t cause any real harm. They also can’t sting you — they don’t have stingers.

They can cause other kinds of harm, but most of these are more annoying than truly problematic. These types of damage include:

  • The bad smells that they release when you squish them
  • Stains to light-colored surfaces from their feces
  • Fruit and leaf deformities in plants that they’ve fed on — this is mainly a problem for orchards that need to rate their fruit based on their appearance 
  • Slight yellowing of leaves in plants that they’ve fed on 

Water can attract boxelder bugs. Once they get inside, you might find them congregating around your houseplants in search of hydration. 

They’re also very attracted to warm places where they can bask in the sun. You’re most likely to find them on the side of your house in the area that gets the most sunlight. 

There are a number of different techniques that you can use to get rid of your boxelder bugs. The best one for you depends on the location and extent of your infestation. 

Some things you can try include: 

  • Vacuuming up the bugs and disposing of the bag
  • Sweeping them out of your house
  • Picking them up one at a time by hand
  • Freezing the bugs that you gather — this will kill them
  • Wash them off of external walls by spraying them with a hose or wiping them away with soapy water 
  • Use low-toxicity pesticides. If you choose this method, always follow the instructions exactly and use proper personal protective equipment (PPE) when handling the chemicals

Unfortunately, aerosolized insecticides that are approved for in-home use aren’t very effective against these bugs. Residual pesticides — that you leave on surfaces — aren’t much help either. 

Sometimes — when the bugs are exceptionally problematic — a professional exterminator will be able to eliminate them much more effectively than you can.  

It’s hard to predict which years will have high numbers of boxelder bugs. Even if they swarm your house one year, there’s no guarantee that they’ll keep coming year after year. This can make it difficult to know when to take preventative measures. 

If these bugs are a common nuisance, though, you may want to consider taking extra preventative measures to keep them out. These include:

  • Caulking and sealing cracks into your home
  • Adding screens or weather stripping to your windows
  • Installing door sweeps to all of the ones that open to the outdoors
  • Removing plants and debris from the edges of your house — this will eliminate places for them to hide
  • Removing their food sources — this is most likely a nearby female box elder tree 
  • Keep seed pods from the boxelder tree off of the ground

These bugs are seemingly useless. They don’t act as pollinators. They’re not — as far as we know — an absolutely necessary food source for any other animals in the food chain. In fact, large infestations can actually disrupt the lives of important pollinators and other useful insects.

Regardless of the bugs themselves, the box elder trees that they live on are great for the environment. Eliminating all of these trees would be a much greater harm to the environment than a helpful method of pest control. 

Boxelder bugs are around most of the time, but they tend to become more problematic in the fall. This is when they need to leave their trees and outdoor hiding places in order to find shelter for the winter. To them, your house is the perfect escape from harsh outdoor weather. 

These bugs can get into your house through any number of small openings, including: 

  • Windows 
  • Doors
  • Ceiling lights
  • Dryer vents
  • Outdoor faucets
  • Fitting in around siding

The bugs enjoy shelter and will seek it out anywhere. All cracks and crevices can make comfortable homes for boxelder bugs.