They can. Asian lady beetles may release a yellowish defensive fluid when disturbed or crushed, and that fluid can leave an odor or stain some surfaces.
Smashing Asian lady beetles against the wall is tempting. But it’s usually not worth it because they can release fluid from their leg joints as a defensive response. Indoors, that fluid can leave yellow or orange marks on walls, curtains, fabrics, windowsills, and other light-colored materials. It can also have a noticeable smell. Removing the beetles is the better way to go.
This problem is annoying with one or two beetles, but it’s especially bad when you have a lot of them. Asian lady beetles commonly gather on buildings during fall before looking for sheltered places to overwinter. Some find their way into wall voids, attics, and other protected spaces, then emerge into living areas when sunlight or indoor temperatures warm them.
Crushing overwintering beetles against your finished surfaces is a bad idea because it often leaves unsightly stains behind. A much more effective approach is to use a vacuum to collect the insects. Just remember to empty the dirt cup or bag right after you finish so the surviving pests do not remain trapped inside the appliance.
You will also want to prevent the next group from getting inside. That requires looking outdoors and checking for ways they might have gotten in. Check window and door frames, siding transitions, soffits, vents, utility penetrations, and other seams for openings. Repair damaged screens and seal appropriate exterior gaps before they start massing on warm, sunlit walls as the weather starts to turn in fall.
If Asian lady beetles are becoming a problem around your Grand Rapids property, Mosquito Squad of Grand Rapids can help with pest control around the property. Call (616) 920-8069 or request a free quote online.
