Lady beetles, also known as “ladybugs” or “ladybird beetles,” are familiar insects. They are considered beneficial because they eat other insects.
However, in some places ladybugs are so numerous they become a nuisance. During this time of year, ladybugs start infiltrating homes in search of a place to overwinter. Large numbers of ladybugs gathering all over the house are not beneficial, especially when they start falling onto food, the bed or you.
Ladybugs have been introduced into the environment because they eat aphids, mites, scales, whitefly, mealybugs and other soft insect pests. They don’t carry disease or sting, but can bite if handled too long.
Ladybugs multiply rapidly. Female ladybugs may lay from 20 to more than 1,000 eggs over a one- to three-month period. Ladybugs overwinter as adults and prefer aggregations along hedgerows, beneath leaf litter, under rocks and bark and in other protected places including buildings. Ladybugs are really only a pest by presence.
They do not feed on or damage anything in the home.
The best way to avoid ladybugs staying over for the winter is to try to keep them outside. Turn off lights near entrances. Do not leave doors or windows open. Ensure all cracks around windows, doors, clap boards and pipes are sealed. Ladybugs do not typically breed indoors. Their numbers increase because of unsealed openings.
To stop them from penetrating your home, insecticides such as Pyrethroids (Bifenthrin/ Cypermethrin-Ortho Home Defense Max) are a great choice. In concentrations used for control, they have insect repellent properties. Cypermethrin is a pyrethroid that provides control for long periods. During the fall, apply this spray on the south and west sides of the house. Those sides are likely targets for ladybug invasion because they are typically the warmest.
During the fall, ladybugs begin coming indoors to find a warm place to overwinter. Cypermethrin will provide a fast kill along with residual protection. Insecticidal soap is another option for a fast kill but it does not provide residual protection. This means new ladybugs will not be affected by the application within a day of treatment. Insecticidal soap requires repeated application and therefore is not recommended.
If a few ladybugs become trapped inside, simply pick them up and return them outside. If they become so numerous that simply returning them outside seems impossible, use a shop vacuum. It is best to line the vacuum with a new bag or pad the bottom of the vacuum container with a cloth. This allows for easy containment and return of the ladybugs outside. Prompt relocation is key because they can crawl out of the bags or vacuum canister.
Light traps might also prove useful if removal proves difficult, especially in dark, confined spaces. Ladybugs, as well as flies, are attracted to the light and heat source. Do not smash the ladybugs to remove them. They have a foul smell if smashed.
You may never rid your home completely of ladybugs, but you can reduce their numbers and make your home more livable. There is no quick fix or easy answer to annual lady beetle invasions. Sealing openings, insecticide applications and vacuuming are the best defenses.