There are several poisons that are available on the market for killing ladybugs, according to BugSpray.com. These include insecticidal soap, cypermethrin and deltamethrin dust. If poison is not a method of choice, there are other options available.
The Ladybug Lady suggests that for a ladybug infestation, homeowners can use a vacuum to remove the pests from their home. A Shop-Vac works best because the bugs can be released back into the wild where they belong. Ladybugs are a great help in the garden, as they kill aphids.
In addition, a black light trap also works well to attract and contain ladybugs that are found in and around the home.