The insects commonly known as ladybugs or lady beetles (or ladybirds, in the UK and other English-speaking nations) include a number of species from the Coccinellidae family. Ladybugs are the subject of nursery rhymes and are considered a good luck symbol by many. For example, the seven-spot ladybird, the most common species in Europe, is said to represent the seven joys and seven sorrows.
Like beloved native ladybugs, the Asian lady beetle or multicolored Asian lady beetle (Harmonia axyridis) is a predator of a number of pest insects, especially aphids, but it has become a problem because it has overtaken native species. Asian lady beetles do not cause much damage to homes or home landscapes, but they often enter homes to seek warmth in cold weather. Once inside, the insects can crawl or fly around rooms and land on windows, walls, and furniture. Like other ladybugs, the Asian variety secretes a yellowish, smelly fluid if disturbed, which can stain walls, furniture, and fabrics. Asian lady beetles may bite if they land on the skin.
Identifying Asian Lady Beetles
Asian lady beetles might look similar to friendly ladybugs at first glance, but there are a few tell-tale characteristics to look out for. First, look at the insect’s head. An Asian lady beetle will have much more white on its head than a ladybug, primarily around its “cheeks.” They will also show an “M”-shaped black spot on their heads, while ladybugs have black heads with a small touch of white.
Asian lady beetles will also typically skew more orange in color than a ladybug, though they do appear in a range of yellows, oranges, and reds. You can also identify an Asian lady beetle through its unpleasant odor and the yellowish fluid it might leave behind as it moves.
6 Ways to Get Rid of Asian Lady Beetles
Asian lady beetles cannot be eradicated outdoors, and there's no point in trying to make your house less attractive to them when they've decided to seek shelter. But there are some simple methods for getting rid of those that make their way inside.
Vacuuming
The simplest and most direct way to get rid of Asian lady beetles indoors is to suck them up with a vacuum. However, since the beetles secrete their stinky odor when distressed (and being sucked into a giant hose seems quite distressing), it's best to use a shop vac for this job, rather than your regular indoor vacuum. Seal and discard the vacuum bag after collecting beetles. To save on vacuum bags, you can also secure a nylon stocking around the exit end of the hose, using a rubber band. Remove the stocking immediately after turning off the vacuum, seal it closed with the rubber band or by knotting the end, and discard it.
Light Traps
Black light traps are effective for attracting and killing Asian lady beetles indoors, particularly in attics and other dark, enclosed areas. You can purchase traps suitable for this use or even make a DIY light trap using basic materials. Make sure the trap's light is the only light in the room so that beetles are attracted to it and not to other lights. Check and clean the trap regularly, especially when the infestation is heavy.
Insecticide Spray
Various consumer-grade insecticide sprays are sold for killing Asian lady beetles. The same sprays are also likely to be effective for boxelder bugs, Japanese beetles, flies, cockroaches, ants, and other pest insects. Sprays are typically applied indoors or outdoors, in cracks and crevices, in storage areas, around window and door frames, and anywhere you find the beetles gathering. Asian lady beetles do not reproduce indoors, so you don't have to worry about targeting nests, as with ants. They may, however, return to the same place the next season.
Seal Entry Points
Any cracks and crevices in your home act as entryways for Asian lady beetles. Check around doors, windows, pipes, baseboards, vents, and any other areas where potential openings may be found. If you do stumble upon a gap, seal it with caulk and use cement and mesh to close off larger holes.
Use Diatomaceous Earth
Diatomaceous earth is a substance made from dried algae that is a common, natural way to prevent pests like Asian lady beetles. It works by dehydrating insects that come in contact with the substance and injuring their exoskeletons. Lay a perimeter of diatomaceous earth around your home to prevent bugs from coming inside, or sprinkle some around windows, door frames, and any other places where insects are likely to try and come inside.
Use Repellents
Natural repellents are an effective way to get rid of Asian lady beetles. Look for one that uses a base of peppermint oil, citrus oil, citronella oil, or any other scent known to deter Asian lady beetles. Spray the solution around any anticipated entry points.
Warning
Follow the manufacturer's instructions carefully when applying insecticide, especially indoors and where children or pets may be present.
What Causes Asian Lady Beetles to Move Indoors?
Asian lady beetles spend the warmest months of the year in outdoor feeding sites, including forests, wild and cultivated fields, and yards and other landscaped areas. When the weather turns cool in autumn, they leave the feeding areas in search of winter shelter. That’s how they end up in your home.
A few factors tend to stimulate this flight for shelter and attract beetles to specific sites:
- Swarms of migrating beetles tend to increase when the sun is out following relatively cool weather.
- Beetles fly most when temperatures are near 65 degrees Fahrenheit and above.
- Flight activity tends to be heaviest in the afternoon.
- Beetles are attracted to areas of contrasting light and dark, such as shaded corners of wall or roofs next to sun-exposed areas, or dark trim against a light background (or vice versa).
- Migrating beetles land on buildings then enter through cracks and crevices.
How to Prevent Asian Lady Beetles from Getting Into Your Home
The best way to control Asian lady beetles in your home is through pest-proofing measures to keep them from entering. These include sealing any cracks around windows, doors, utility wires, and pipes, and vents, as well as gaps or cracks in the siding, eaves, and foundation. It also is important to be sure that all doors and windows are tightly fitted and that screens are not torn or ripped. Insecticides applied around doors, windows, and other entry points (like cracks and crevices) can help keep beetles from entering the home. These must be applied before the beetles come into the home; they are not effective once the bugs are inside.
Gardeners seeking to introduce beneficial insects should take care not to purchase and distribute ladybugs from commercial sources because the ladybugs may be the Asian variety. While some "safe" species are sold, including Hippodamia convergens (convergent ladybug), Adalia bipunctata (red ladybug), and Coleomegilla maculata (spotted ladybug), these insects may have been harvested in the wild to offer for sale, which is a questionable practice.
A better strategy is to practice gardening methods that encourage native ladybug species to visit your garden.
Asian vs. Native Lady Beetles
Ladybugs are not true bugs, but rather a group of some 6,000 types of small beetles that share a similarity in markings: orange or scarlet shells with black spots. These insects are more accurately called lady beetles. Most of the species are considered beneficial insects, since they feed on agricultural pests such as aphids and scale insects. Some species are natural predators of very serious pests such as the European corn borer.
The Asian lady beetle, the most prevalent North American ladybug, was introduced to the U.S. from Asia in 1916 to combat aphids. The USDA released the Asian lady beetles in Georgia, South Carolina, Louisiana, Mississippi, California, Washington, Pennsylvania, Connecticut, and Maryland, and the beetle has since then migrated throughout most of the United States. Along with this intentional introduction, it is likely the beetles reached the U.S. on freighters, adding to its presence throughout the country.
At a quick glance, it can be hard to tell the difference between the Asian ladybug and the native ladybugs, partly because the color of the Asian species can vary from light tan or orange to bright red, making them almost identical to some of the native species. But if you look closely, you will see the Asian ladybug has a white marking behind its head in the openings of what looks like a black "M." Some also have dark black spots, but on others, the spots are very light or nonexistent.
When to Call a Professional
There are scenarios where it is wise to call in a professional exterminator instead of opting to handle the infestation yourself. If there are more insects that you can handle, the infestation is recurring, or if you are having issues identifying the source of the infestation, a pro will help you eradicate these pests once and for all.
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What Is Beetle Stain?
The so-called stain left by Asian lady beetles and other ladybugs is a small drop of yellowish liquid. It’s a secretion of compounds emitted to fend off predators such as birds. The secretion has an unpleasant acrid odor.
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Do Asian Lady Beetles Harm Plants?
Despite their invasive nature, Asian lady beetles do plants more good than harm. Their primary diet is aphids, which infest many garden plants and are among the most ubiquitous and persistent garden pests. They also feed on scale insects, another group of common garden pest.
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Do Lady Beetles Carry Diseases?
Asian lady beetles are not known to carry diseases and do not transmit diseases to humans.
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What scents deter Asian lady beetles?
There are numerous scents that deter Asian lady beetles, some of the most potent are: citrus; mint, peppermint, and menthol; bay leaves; cloves; and citronella (like many other insects).