Lee Royer
Frederick County Master Gardener

Once upon a time to find a ladybug in your house was a sign of good luck. These days, ladybugs are invading more and more homes each year and few of us count our selves lucky when this happens.

Ladybugs are actually beetles and, as many people know, are beneficial insects that feast on plant lice called aphids and other soft body insect pests that destroy our garden plants and field crops. Even small children quickly learn to recognize the cheery round shape, bright red or orange color and black spots of ladybugs. Europeans during the Middle Ages dubbed them "The Beetles of Our Lady" after they were discovered to rid grapevines and other crops of pests, hence ladybugs. Entomologists know them as the Family Coccinellidae and there are many species worldwide, about 200 residing in North America.

Your house invading nuisance species is most likely to be the Multicolored Asian Lady Beetle (Harmonia axyridis) imported and released in mass as a biological control agent since at least 1916 by farmers and government agencies. Not until the late 1980s were established colonies documented by scientists in Georgia and Mississippi. Since then they have been found in large numbers across most of the US and as far north as Ontario, Canada. It is also possible that these first established populations were accidentally introduced from commercial activity at the port of New Orleans. However they got here, they are here to stay as long as the food lasts.

Ladybugs get through the winter by hibernating in adult form. Many species in the wild choose rock crevices for this purpose but a house offers even more opportunities to hide behind wood or plastic siding. Since they don't become active unless the temperatures go above 55, during a cold winter they might stay quietly hidden behind your siding until the weather warms up in the spring. During warm spells the outside of our homes easily heat up to 55 degrees, and the ladybugs break hibernation to search for aphid infested plants on which to lay their eggs. So warmer winters equal more chances for ladybugs to break hibernation and go searching in your house for aphids.

Thank goodness ladybugs do not reproduce indoors like fleas or roaches, nor do they sting, bite so as you'd notice, carry diseases or feed on anything other than soft bodied insects. They do secrete a stinky yellowish liquid that makes them taste bad to predators such as birds and which stains surfaces and fabrics, especially when they congregate in large numbers. And who enjoys the crunch of stepping on a ladybug in the middle of the night?

Most commercially available spray insecticides will kill ladybugs, however you are replacing a relatively benign problem with a definitely hazardous material and dead or alive you will need to pick them up to remove them. If you want to change the problem into a bonus for your garden, try this method: attach with tape or heavy rubber band a knee high nylon stocking to the end of your vacuum cleaner hose, stuffing it inside the hose. Then vacuum the bugs into the stocking net you created. When finished bug catching, close the open end of the stocking with a twist tie or knot and put them in a dark, colder than 55 degree, but not freezing place until spring when you can then release them into your garden. The going rate for ladybugs is around $7.50 plus postage for 2,000 so you can calculate your savings.

That sticky stinky yellow liquid also contains chemical clues that attract the bugs back to the same places each winter so unless you want to continue collecting ladybugs year after year, you will need to take the offense by making sure your home is well caulked and all bug size crevices are filled as well as making sure your window and door screens are in good condition. Exterminating them completely is probably near impossible given the small size of ladybugs but it's worth a try for large infestations.

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