Asian Lady Beetle

Asian lady beetles can be considered both a beneficial insects and an annoying pest.

Gardeners, farmers and orchardists consider lady beetles to be a beneficial insect because they feed on plant pests. While there is no doubt that the Asian lady beetle is helping to control aphid and scale infestations outdoors, home owners are not as enchanted by the little pests finding their way indoors. The words good, beneficial, need to protect them, do not enter a home owners mind as the lady beetles are swarming around and crawling inside their home or garage.

The Asian lady beetle (Harmonia axyridis) body color can vary from yellow to red. Some may have black spots but the most apparent identifying characteristic and diagnostic tool is that Asian lady beetles all have a black ‘M’ on their thorax, just above the wing covers.

Another pest that has invaded our homes is the brown marmorated stink bug. Its mottled brown body has a shied shape to it and it releases a nasty odor when threatened or crushed. This insect has no redeeming qualities like the aphid eating lady beetle. This bug has the potential to become a serious pest to fruit growers. The bug uses its sucking mouthparts to feed on fruit crops, soybeans, corn, some vegetables and a variety of ornamental plants.

Their search for a place to winter is usually initiated by the first cold weather snap in mid-October. Lady beetles are attracted to buildings with abrupt color differences like dark shutters on a white house and usually appear on the southwest-facing side. They also like buildings close to trees or woods.

When the outdoor temperatures fall these pests move into any tight crack or crevice, such as under siding, window sills and door jams. Once they find a cozy spot they basically stay in a hibernation-like mode until the first warm days of late winter or early spring. And then “THEY’RE BACK”! At that point they are attracted to the living quarters of the humans where temperatures are more comfortable. These pests do not directly damage anything in the home, they are just an annoying nuisance and release a nasty smell when handled or disturbed.

There have been some reports that particles from accumulations of dead beetles may become airborne and complicate allergies or asthma if inhaled by people.

Control options depend on how many pests you have and your level of tolerance. Vacuuming them up works very well but be sure to either empty the bag right away or place paper or plastic over the hose when finished. They will find a way out of the vac while it is stored in the closet if this is not done. Pesticides can be used as a perimeter treatment in late fall while the beetles begin to congregate but before they enter the home. Chemicals that will leave a long lasting residue will work the best. Another preventative measure is to seal them out by caulking around utility service areas, windows, door jams, foundations and any other cracks. In the event that all of your measures do not work, you can always call a professional pest exterminator.

Happy de-pesting!

Karen Weiland is an advanced master gardener.More information about gardening and related subjects is available online at hort.purdue.edu/ext/garden_pubs.html. The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange County, 636-2111 in Noble County, 925-2562 in DeKalb County and 668-1000 in Steuben County.

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