Box Elder Bugs

Facts, Identification, & Control

Latin Name

Boisea trivittata


What Do They Look Like?

box elder bug picture

  • Size: These bugs measure between 11 to 14 mm long.
  • Color: Box elder bugs are black in color and have red lines along the thorax sides. Their wings are flat and red in color.

How Did I Get Box Elder Bugs?

Box elder bugs are attracted to cool temperatures and warm sunny side houses. They cluster in warm areas on siding and roofs to make their way indoors. Once inside, they hibernate through fall and winter.

During the fall, these pests may enter homes and buildings through:

  • Cracks in window frames
  • Gaps and crevices
  • Tears in screen doors

How Serious Are Box Elder Bugs?

Box elder bugs do not bite or spread disease. They do not cause damage to buildings, but they extract juices that cause minimal to sustainable damage to their host trees.

Signs of Infestation

Like many overwintering pests, the most startling signs are when they invade in staggering numbers.

Some other signs of infestation from box elder bugs include:

  • Buzzing sounds
  • Dropping stains
  • Odor released when crushed

How to Get Rid of Box Elder Bugs

What You Can Do

To stop box elder bugs from multiplying, it is often helpful to remove their host trees from the area surrounding your home, but the adults can still fly to locations off of the property.

If you choose to plant box elder trees in your yard, choose male trees (non-seed-bearing) since female trees are more susceptible to infestation. These trees are not recommended for ornamental planting.

What Orkin Does

In some homes, chemical product treatments might be necessary. Your local Orkin technician is trained to help manage box elder bugs and similar pests. Since every building or home is different, your Orkin technician will design a unique program for your situation.

Orkin can provide the right solution to keep box elder bugs in their place and out of your home or business.

Behavior, Diet, & Habits

Their presence is bothersome due to the scent they emit when crushed and their tendency to fly around living spaces. They may emerge from walls when heat sources within the building are high and they can be located in the warmest areas of a structure’s walls.

Box elder bugs do not nest indoors year-round. While overwintering, they do not feed or reproduce. During warmer seasons, they make their homes in box elder maple and ash trees.

Dropping Stains

Their droppings are unsightly and leave difficult stains to remove on:

  • Curtains
  • Furniture
  • Linen
  • Walls
What Do They Eat?

These bugs feed on soft parts of box elder trees including:

  • Flowers
  • Juice from host trees
  • Leaves
  • Twigs

Life Cycle

Life Stages
Adult box elder bugs live and breed on leaves of box elder trees.

These bugs prefer to lay their eggs in these trees during spring. Their eggs are reddish brown in color, allowing them to stay well hidden in the bark of the host tree.

After a few days, the eggs hatch into red and gray nymphs, which eventually mature and begin the breeding process again.

Mature box elder bugs can be found gathering in large numbers on branches and boughs. Concentrations will be heaviest in areas receiving sufficient sunlight.