Grow Guide: Ladybug Home Invasion
The best approach if you have ladybugs in your house is to prevent them from coming in by sealing cracks around windows, doors and roof soffits.
Q: Help! I am finding ladybugs in my house by the dozens. Why are they coming in and what can I do about them?
First off, calm down because ladybugs (also known as lady beetles) will not harm your house. They eat aphids, not fabric or wood. Besides, if you upset them they can quickly excrete a protective smelly yellowish fluid that can stain. Some folks just hate insect infestations. But the beetles are relatively harmless, though some, if given a chance, may lightly nibble on your skin. Have I mentioned that they are not very bright?
They are in your house because in nature they hibernate over the winter in masses, usually in protected places like cracks in rocks, tree trunks and other warm places, including buildings. When one finds a suitable spot in the fall, it produces a pheromone that attracts others, so it is common to find dozens if not hundreds at a time. And often a few misguided beetles get confused and come into rooms through electrical outlets and other openings in walls.
Go With The Flow
Unfortunately, there are no really good ways to handle lady beetle infestations. Once they get in, they are nearly impossible to get rid of until spring when they naturally head back outdoors. Trying to kill those that are hibernating in wall cavities is rarely effective.
Sweep them out, being mindful of the yellow secretion they can leave on walls. Use a vacuum cleaner on large infestations. If you want to release them outdoors, put a piece of paper towel between the vacuum hose and the collection bag as a trap.
The best approach is to prevent them from coming in next fall by sealing cracks around windows, doors and roof soffits. But this may be impossible in the long run.
And by the way, “ladybug houses" sold in garden supply catalogs usually don’t do a very good job at keeping the beetles out of your home.