Billions of ladybugs have been busy eating aphids in the soybean fields and have been absent from in and around our home all summer. However, it will soon be time for them to start congregating on the outside of our homes and we may see large numbers of them on sunny days. Once they gather on the outside of the home it’s time to use some preventative measures or we will soon find the pesky insects inside. The “ladybug” is a multicolored Asian lady beetle, which is an imported lady beetle that has become a common household pest. The lady beetles are very beneficial as predators on aphids and scale insects, but become a pest when they congregate in large numbers around and inside homes. These beetles become a nuisance not only by their presence, but also by staining surfaces with a defensive fluid they secrete, giving off a disagreeable odor and by pinching the skin. Repeated exposure to dead beetles can cause an allergic reaction in some individuals. The multicolor lady beetles generally start to enter homes sometime in mid- to late October. The large numbers congregating on homes at this time indicates that they are beginning to enter homes now. Prevention is the most effective step in controlling lady beetles. Check the outside of your home for spaces and cracks that may allow easy entry for insects. Install tight-fitting door sweeps or thresholds at the base of all exterior entry doors. Gaps of 1/16 inch or more will permit entry of insects. Seal openings where pipes and wire enter the foundation and siding using caulk cement, urethane expandable foam, steel wool or other suitable construction sealant. Caulk around windows, doors, chimneys, fascia boards, etc., using a high quality silicone or acrylic latex caulk. Repair gaps and tears in window or door screens as well as the screens in roof and soffit vents or bathroom and kitchen fans. Physical exclusion will probably need to be supplemented with an insecticide application. For insecticides to be effective, they must be applied before insects begin to enter the home. Insecticides available for use by the public include bifenthrin (Ortho Home Defense Indoor and Outdoor Insect Killer) and cyfluthrin (Bayer Advanced Insect Control). Be sure the product you choose to use is labeled for use on the exterior of buildings. Apply the insecticide according to label directions to soffits, siding, foundation, windowsills and door thresholds, paying particular attention to the south and west sides where the insects congregate in the largest numbers. You may consdier hiring a professional pest control service as they have the experience and access to effective residual insecticides that are not available to the public. Once lady beetles get inside the home, there are few options but to physically remove them with a vacuum. The use of insecticides indoors is of very limited value. The lady beetles that enter the home move into wall voids and similar places where there is no practical control. They will then emerge during winter and spring and must be tolerated or removed physically.
