We are well into November, and the weather is becoming chillier by the day. Nothing feels better than coming home to a warm, comfortable house after a cold day at work. Unfortunately, insects feel the same way. Ladybugs are some of the most notorious nuisance pests when it comes to unwelcome insect intruders.
Ladybugs, or as they are known in the science world, Multicolored Asian Lady Beetles, are non-native insects that normally do more harm than good. They prey on garden and crop pests, such as scale insects and aphids, and help reduce overall pesticide usage.
In fact, they are so good at controlling crop pests that they were intentionally released by the USDA. According to Susan Jones, an Ohio State Entomology professor, Georgia had the highest number of Asian lady beetles introduced (11,000) in the 1970s-80s. These were a big help with controlling the pecan aphid, a big pest in South Georgia’s many pecan orchards. However, with the lack of natural predators in the US to help control their populations, Asian lady beetles soon became household nuisance pests.
Ladybugs become a problem when they enter our homes when the weather begins to turn cold. There are many species of lady beetles which are native to the US, but they do not actively seek out homes for overwintering sites like their Asian cousins. Asian lady beetles naturally overwinter in cliffs, but in the US, homes make a nice substitute.
A typical home infestation will start with a small group of ladybugs congregating on the side of a house, usually near a window or door. They release pheromones which attract more and more ladybugs. Some of them will work their way in to cracks in siding, through broken window screens, and under drafty door thresholds.
Once they get in your home, ladybugs can be a headache. When disturbed, they excrete an orange liquid (blood!) that can permanently stain carpets, floors, walls, and curtains. Ladybugs have also been known to “bite” or “nibble” on human skin. This usually not painful, and in no way harmful, but most people don’t like the idea of insects nibbling on them inside their own homes. Rare cases of allergic reactions have also been reported due to ladybug exposure, but these are relieved after proper removal of the insects.
Once ladybugs have entered your home, it is best to physically remove them. Using a broom or crushing them will cause them to leave behind their orange excretions that will stain your household surfaces. Try attaching a nylon stocking to the hose end of you vacuum cleaner with a rubber band. The stocking will act as a net and keep the ladybugs from being sucked into the bag or canister. If you can’t use the stocking method, be sure to empty your vacuum frequently.
To prevent ladybugs and other insects from entering your home, minor maintenance may be required. Repair or replace damaged window screens. Install door sweeps on exterior doors. Replace the vinyl seal on the bottom of your garage door with a rubber one. It will seal better in cold weather. Seal any cracks or openings around the exterior of your house. Install mesh screens over attic vents to prevent easy entry points.
Household pesticides may also be used as an effective barrier. Household insecticides containing active ingredients ending in “-thrin”, such as bifenthrin, cyfluthrin, deltamethrin, and many more, are effective exterior sprays. Only apply these to the outside of your home.