ID #1018

FAQ-What are the massed bugs on and in my house and how can I get rid of them?

It is likely that the bugs on your house are either boxelder bugs or lady beetles. Especially in the fall, both of these insects are attracted to buildings with a large southern or western exposure, or buildings that are taller than, or isolated from other structures, or buildings close to large trees.

Boxelder Bug
The boxelder bug is a good example of a nuisance insect. Adult boxelder bugs are about 1/2-inch long, brownish-black with orange or red markings, with three stripes just behind their head, and a bright red abdomen.

Lady Beetle
The lady beetle (also called ladybug or ladybird) is a well-known beneficial predatory insect that can actually devour more than 5,000 aphids in its lifetime. The lady beetle is oval in shape, about 1/4 to 3/8 inch long, has a red or orange body with black spots, and a black head with white markings.

Both boxelder bugs and lady beetles are relatively harmless. The boxelder bugs may feed on boxelder, maple or ash trees, but don’t noticeably injure the trees. The Asian lady beetles don’t carry diseases or sting but they can leave a discolored "spit" and can pinch your skin with their tiny mandibles. Both insects can produce an odor and boxelder bugs can stain your wall or carpet red if you crush them while lady beetles exude a yellow-orange-colored substance from their joints.

What to Do About Them

If the bugs are on the outside of your house, you can simply ignore them and hope that the lady beetles stick around until spring to help keep your aphid population under control!

If the boxelder bugs are really “bugging you,” you can:

  1. Remove any female boxelder trees near your house. (The bugs aren’t attracted to the male trees.)
  2. Move any piles of rocks, boards, leaves, or debris near your house.
  3. Remove weeds and grass from a strip between six and ten feet wide around your foundation, or at least on the south and west sides of your house.

If bugs have found their way into your house, which they’re more likely to do as the temperature drops, it’s time to thoroughly inspect your home and fix, block or seal up any possible holes or openings where insects could gain access. Repair any torn window or door screens and fix any gaps around the edges. Seal up openings with silicone caulking, weather stripping and/or foam in spaces around windows or wherever electrical wiring comes through the wall. Attach weather-stripping or “sweep strips” to the bottom of your doors. Install insect screening over your attic and exhaust fans, vents, louvers, and crawl space openings. Sealing gaps and cracks will not only keep out other annoying insects besides boxelder bugs and lady beetles, but will help make your home more energy efficient as well!

Sites to Learn More
Check out the following sites for more information about dealing with boxelder bugs and lady beetles:

How to deal with boxelder bugs without pesticides

Extensive boxelder bug information including pictures and how to manage the bugs in different types of home construction

Info on Asian lady beetles from Oregon State Extension Service 

Oregon State 4-H info about lady beetles including species description, where they live and why, creating habitat for them, and fun facts

Pictures of Oregon lady beetles and Asian lady beetles

Tags: boxelder, boxelder bugs, boxelder tree, insects, lady beetles, ladybird, ladybug, massed, south side, sunny

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