Box Elder bugs Identification & Biology

By DoMyOwn staff

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Physical Appearance

  • Box Elder bugs are about 1/2 inch long and 1/3 as wide.
  • Boxelder bugs are black with three red lines on the thorax, a red line along each side, and another on each wing.
  • The wings of a Boxelder bug lie flat on the back when at rest.
  • Young Box elder bugs, or nymphs, are gray and red.



Boxelder bugs are most likely to be found feeding on the leaves and flowers of the female boxelder and maple trees, but may also be found on other fruit and nut trees and plants. Box Elder bugs become a problem to homeowners during the winter when they migrate indoors searching for a warm place to spend the winter. Large numbers of Boxelder bugs may hide in small cracks and crevices in walls, door and window casings, attics, and around the foundation.


Life Cycle

Adult Boxelder bugs which have spent the winter indoors will lay eggs in the spring, with nymphs emerging in just a few days. These nymphs then develop into adults by mid-summer, and mate and lay eggs of the second generation. Activity of the second generation of Boxelder bugs is noticed in early fall when they gather on the trunks of boxelder trees in large numbers. This second generation continues the cycle of "overwintering" (hibernating, so to speak) and will lay eggs again in the spring.



Boxelder bugs cause little damage to most trees. Those feeding on fruit trees can cause damage and distortion to developing fruit. Indoors, Boxelder bugs are also relatively harmless except for tough-to-remove excrement spots they sometimes leave on draperies when they get inside during the fall and winter. They will not eat anything in your home including plants, do not reproduce indoors, are not poisonous if accidentally eaten, and are not carriers of any diseases. Once they get inside, the best tool you have on your side is the vacuum cleaner. Just suck ‘em right up!



For more detailed information on Box Elder prevention and control, see How To Get Rid of Boxelder bugs.


View Box Elder Bug Control Products






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