Are You Seeing Box Elder Bugs?
Is it just me? Does it seem like Box Elder bugs have been worse last couple of years? I don’t know what
this year will look like, but we have been seeing them more and more over the last few weeks. Box
Elder bugs are most often seen on or inside residential structures twice a year; in the spring and in the
fall. If you have these bugs, you may be wondering- “Where are they the rest of the year? Where are
First, let’s make sure we are identifying these correctly. Adult Box Elder bugs are about 1/2-inch long,
black with orange or red markings, including three stripes on the prothorax, the area right behind
the head. Their wings lay flat over their bodies, overlapping each other to form an ‘X’. The immature
nymphs are 1/16th-inch long and bright red when they first hatch. As they grow older they go through
several molting stages and gradually become larger, becoming more black than red. You can potentially
see all stages at any given time during the summer or early fall.
In the spring, Box Elder bugs tend to leave their overwintering sites as the weather begins to warm up.
Adults feed on seeds and other vegetation during this time. After feeding for a couple of weeks, they
start to mate. This takes place during the late spring and early summer. By mid-July, the Box Elders
have begun a pilgrimage to find female seed bearing box elder, ash, or maple trees. They lay their eggs
on tree trunks, branches and leaves. When populations are high, you may see nymphs living in the
mulch around your bushes, or in gardens where they can feed throughout the summer.
In the fall, the box Elder bugs begin to travel back to a place where they can be protected throughout
the cold. Some Box Elders may travel only a few hundred yards, others may travel up to two miles! It
just so happens that one of the safest places for them to overwinter is within the walls of your home.
Box Elder bugs will be attracted to homes with good southern or western exposure. The amount of sun
your home receives on these two sides will directly correlate to the number of Box Elder bugs sunning
themselves on the exterior, and eventually moving inside the walls of your home.
As the weather cools, Box Elder bugs will push themselves into cracks, crevices, beneath your siding, and
into your wall voids behind the insulation. At times, they may end up inside your home, although that
is not their intention. During winter Box Elder bugs are generally inactive. By spring, as they feel the
warmth from the exterior of the home, they begin to move toward it and eventually outside. Box Elder
bugs do not reproduce inside the walls of the home, or in the winter. Each bug that emerges is one that
entered the structure the previous fall.
Box Elder bugs are not harmful. They are simply nuisance pests and will buzz around you or sometimes
end up inside the home. There are several ways to minimize the effects that have on you and your
* Repair or replace damaged window and door screens.
* Repair or replace damaged screens in roof and soffit vents, and in bathroom and kitchen fans.
* Seal areas where cable TV wires, phone lines, and other utility wires and pipes, outdoor faucets,
dryer vents and similar objects entering buildings.
* Seal with caulk or for larger spaces use polyurethane expandable spray foam, copper mesh, or
other appropriate sealant.
* Install door sweeps or thresholds to all exterior entry doors. Install a rubber seal along the
bottom of garage doors.
Following these tips will help you to prevent or slow Box Elder infestations from manifesting themselves
indoors. However, this will not provide relief from these nuisance pests on the exterior of your home or
around your doors and windows. If Box Elder bugs are a bother to you on the interior or exterior of your
home, you may want to consider the help of a pest control professional.