Protect Your Home From Asian Lady Beetles

Un-invite Asian Lady Beetles

Fall’s cooler temperatures are tempting Asian lady beetles to invite themselves into homes throughout the state. Once they check in, they plan to stay and be snug all winter.

If you own a light-colored house with a southwest exposure near a wooded area, you are more likely than most to be their winter lodging choice. But you can un-invite your unwanted guests.

Use Home Controls

Here are some home control methods to keep out most insect pests, including the Asian lady beetle.

1. Seal windows and doors with weather stripping.
2. Prevent the beetles’ entry by caulking cracks around windows, doors, utility pipes and siding.
3. Pay special attention to windows and lighting fixtures since the beetles are attracted to light.
4. Install 20-mesh or finer screen over attic and exhaust vents.
5. Check attic and basement for possible entry sites.
6. Use vacuum cleaner or a broom and dustpan to pick up beetles. To avoid possible damage to the vacuum, use a sweeper attachment with a knee-high nylon hose inserted in the end.
7. If spraying for beetles inside, pick up dead beetles with vacuum cleaner. They then can be disposed of outside.
8. Seal between logs if residence is a log home.

Use Chemicals Carefully

Asian lady beetles are not the most gracious house guests. As a homeowner who has been visited by these critters for the past three years, I understand how much a nuisance they can be. A few hundred, we can deal with, but thousands are a different story. When lady beetle swarming time arrives, I spray all window and door frames, garage door frames, siding joints, roof eaves, basement sills, and any other cracks or crevices with an all purpose indoor/outdoor insecticide.

Ortho’s Home Defense, Bayers Advanced Home, and Spectracide Bug Stop Indoor & Outdoor Home Insecticide are labeled for both indoor and outdoor use. These are only three of many products that do a good job of keeping out ants, earwigs, lady beetles and other unwanted insects.

These insecticides are effective for three weeks to as long as four months. Always read the label to get proper recommendations for repeat applications.

Be sure to follow all other label recommendations and precautions. Following label recommendations is not only required by federal law, but insures the safety of yourself, children, pets and food.

About Those Beetles

Outdoors, Asian lady beetles are quite beneficial. As predators of aphids associated with trees, shrubs, ornamental plants and some agricultural crops, they are reported to be better than our native lady beetles at tracking down aphids.

Multicolored Asian lady beetles are not poisonous or otherwise harmful to humans, pets or property.

They do not reproduce indoors. However, the mere presence of such large numbers inside homes can be a major nuisance. The Asian lady beetle does not carry disease, but it will bite in rare cases. Some people may be allergic to the oily substance they excrete.

Females winter in protected sites unmated. The majority of the population mate later in the spring. Eggs generally hatch in three to five days. The larval stage lasts 12 to 14 days, and the pupal stage, which takes place on leaves, lasts five to six days. In cool spring weather, development from egg to adult can take 36 days or longer.

After emergence, adults can live as long as 2 to 3 years under optimal conditions. A beetle consumes about 300 aphids before it reaches adulthood, feeding on more than 50 aphid species.

After you have made sure that the garage door is closed, doors and windows sealed, attic and eave vents patched, openings around the siding edges closed up, and the exterior of your house treated with an insecticide labeled for control of insects outdoors, you will have prepared about as well as you can for our fall “friends.”

For more information about controlling insects around the house, contact your local county Extension office.

This article was written by Dr. William Shockey, a WVU Extension agent in Preston County. His column appears Sundays in the Dominion Post in Morgantown, W.Va.

Trade or brand names used in this publication are for educational purposes only. The use of such product names does not imply endorsement by the WVU Extension Service to the exclusion of other products that may be equally suitable.