What are Boxelder Bugs?

The Boxelder bug (Boisea trivittata) is a very familiar Ontario insect, named after its host, the boxelder tree, which is known for its spinning helicopter-like seed pods. These insects are from the Rhopalidae family, the so-called "scentless plant bugs”

Boxelder bugs live on seed-bearing boxelder, ash and maple trees during warm months, where they feed on seeds, fresh twigs, flowers and leaves. In the spring these host trees are also their breeding grounds, and where they lay their eggs. In dry summers boxelder bugs have been known to feed on fruit, such as peaches, plums, and cherries.

Boxelder bug populations are most abundant in warmer months. That being said, the volume of these insects does vary greatly from place to place, as well as from year to year.


What do Boxelder Bugs Look Like?

The bodies of adult boxelder bugs are 11 to 14 mm long, appearing long and flattened. They are black, marked by red lines along the side and thorax and a reddish-orange coloured abdomen. They possess flat, red wings. Adult boxelder bugs are at times mistaken for a stink bug.

A picture of a boxelder bug


Freshly laid boxelder bug eggs are oval shaped with a straw yellow colouring. They turn a rust-red or rust-brown as the embryo develops inside. This coloration is important as it allows the eggs to blend in with the tree to help protect them from hungry predators. The first instar nymphs are wingless, with bright red abdomens and black legs and antennae. They measure about 1.3 mm in length. As the nymphs mature through all instar stages, they become a deeper shade of red.


The Life Cycle of a Boxelder Bug

Boxelder bugs can produce 1 to 3 generations each year depending on the region and habitat. They have a lifespan of about one year.

In late April to early May, when the weather begins to warm up and boxelder tree buds begin to open, boxelder bugs emerge from overwintering (hibernating). The insects fly to their host trees for shelter, nourishment and breeding.

Most often in early May, female boxelder bugs will lay eggs in the crevices of the bark and leaves of their host trees. They may also lay eggs on the ground in leaf litter or grass. Each female boxelder bug can lay 200 to 300 eggs. The eggs develop for an average of 14 days. Boxelder nymphs have 6 instars, meaning they molt (shed their exoskeleton) 5 times before they become an adult insect. The length of time spent in each nymphal stage depends on the temperature of their environment and food availability. Under the right conditions, nymphs can grow to adults in the same season that they were born in, which means that first-generation adults are able to mate and produce a second generation of boxelder bugs within the same season. A third generation is also a possibility.

When the weather cools and fall begins to set in, boxelder bugs begin to seek refuge to overwinter. While adult boxelders are capable of overwintering, nymphs are not, and will likely die.


Do Boxelder Bugs Bite?

Boxelder bugs are sap-feeders of their host plants (leaves, new twigs, flowers, etc.). They do not bite or feed on people or animals. Boxelder bugs are of no health concern to humans or pets. They are also not a sign of unsanitary conditions.

There have been some instances, where in self-defence, their piercing-sucking mouthparts have punctured human skin. The result was a red spot, similar to a mosquito bite, and a slight irritation. Overall, there have not been any noted lasting effects.


Do Boxelder Bugs Cause Damage?

In nature, Boxelder bugs have been known to cause minimal to substantial damage to the host plants they feed on. Because adult boxelder bugs and nymphs extract plant fluid from newly developing leaves, the foliage could become distorted. Damage could also be done to flowers, tender twigs, and seeds of host trees.

In homes and around humans, boxelder bugs are a nuisance pest. In cases of large infestations, thousands of boxelder bugs may invade living spaces. They leave a reddish-orange stain when crushed or roughly handled, which can cause staining of clothing, curtains, linens, carpeting, walls and furniture. Their fecal matter is unsightly and leaves a stain. If boxelder bugs die within a home or building’s wall voids, they may attract carpet beetles, who will feed on their carcasses. These carpet beetles may subsequently attack any stored dry goods, woolens, or other natural products in the home.


Boxelder Bugs in the Homes and Businesses

Why do Boxelder bugs infest homes and building? By mistake. In late August they concentrate in large numbers on the south sides of trees, rocks and buildings to bask in the warm late summer sunshine. As the weather cools, especially at the end of day, they seek out warm protective shelter to overwinter. Boxelder bugs wander into houses through tiny cracks and crevices with the building, and gain access to attics and wall voids.

Boxelder bugs congregated on the south side of a building.


How does a Boxelder Bug Infestation Happen?

All spring and summer long, boxelder bugs live, feed and breed outdoors in boxelder, maple and ash trees. In the fall when the cooler weather arrives, most seek shelter outdoors in the cracks of bark, or under leaves and other natural debris.

Like many other overwintering pests in the late summer and early onset of fall, boxelder bugs congregate in huge masses on the south side rocks, trees and buildings where the sun shines strongly. As the weather continue to cool down through each passing day, they find entry into nearby buildings or homes to overwinter through small cracks and crevices in foundations, doors, windows, eaves, etc.

Once inside a home or building they hide and hibernate through fall and winter. Boxelder bugs do not reproduce or feed during these months. They do dormant. In the spring they become a real nuisance once they awaken and seek to gain access to the outdoors. This is when homeowners or businesses first see evidence of the bugs, often in overwhelming numbers. As well, if winter weather becomes unseasonably warm, and helps to heats up the wall voids or attic, these pests will awaken early, catching homeowners off -guard by crawling into their living spaces and flying to windows.


How to Get Rid of Boxelder Bugs

Prevention in both fall and spring is the best approach for getting rid of boxelder bugs. Pest proofing your home or building helps to minimize the chances and number of insects that gain entry. Here are some things that you can do to help prevent a boxelder bug infestation:

  • Repair holes in damaged window and door screens.
  • Install or repair screens in roof and soffit vents.
  • Install door sweeps on exterior doors.
  • Use a good quality silicone or silicone-latex caulk to seal exterior cracks, crevices, gaps and holes around:
    • Windows, doors, siding, eaves and fascia boards.
    • Roof joints and behind chimneys.
    • Places where utility pipes, plumbing, wires or cables enter the building.

Some homeowners or property management companies may be tempted to cut down a boxelder or maple tree on the premise if they have a boxelder bug infestation. The boxelder bug is a mobile insect. Therefore, this will not remedy an infestation, nor necessarily help to prevent another one from occurring.

If you are truly looking for how to get rid of boxelder bugs effectively, it is through the help of a pest management expert. Having the perimeter of your home and building treated by a licensed pest control professional with a residual spray, especially the sunny side, prior to their migration indoors in spring and fall will help keep pests out.


How to Control a Boxelder Bug Infestation

If your living spaces are being invaded and overrun by boxelder bugs you can bring about some temporary relief by sealing entry points and using a vacuum or broom for removal of visible insects.  

First attempt to locate the openings within your home where the boxelder bugs are coming out from. Typically, boxelder bugs will emerge from cracks under or behind baseboards, around window and door trim, and around exhaust fans or lights in ceilings. Seal these openings with caulking to prevent further insects from crawling or flying out.  They also hide in household clutter, so check around your home for areas of clutter to identify possible infestation sources.

To remove the active, visible boxelder bugs in your space, a vacuum cleaner is most effective as it will suck up the bugs, living and dead. Avoid using a fly swatter. Hitting or squashing the insects will cause staining. Also, immediately dispose of the vacuum bag or empty the canister outdoors to prevent any surviving bugs from escaping back indoors.

When attempting to get rid of boxelder bugs in wall voids, no attempt should be made to kill them without a licensed pest control technician. This is because dead insect bodies can attract carpet beetles. A pest management professional experienced with boxelder bug control will know how to safely and effectively get rid of boxelder bugs in your wall voids and any other place that they are hiding in.

We understand that in some situations, comprehensive pest proofing can be too time-consuming, impractical and even ineffective. This is why for large infestations with unbearable numbers of insects, contacting a boxelder pest control professional is your best course of action for getting rid of boxelder bugs.

Call 1 (800) 263-5055

Our Professional Team is Happy to Help!