By Sam Wasson
Updated Oct 10, 2022
Finding a ladybug is often considered a sign of good luck, especially if you come across one in the garden. These tiny bugs are known for their helpfulness in the garden and bright red coloration. However, ladybugs are often confused with several other, more problematic insects, namely, Asian lady beetles and occasionally Mexican bean beetles. While both of these ladybug imposters are pest species, Asian lady beetles are known to congregate and multiply inside homes during colder months. If left unattended, these nasty bugs can become a severe nuisance and may require some serious pest control.
Ladybugs, also sometimes called the “ladybird bug,” are red beetles with black spots and white markings from the Coccinellidae family. These helpful bugs are harmless to humans as they carry no diseases, do not bite, and are not known to congregate in large numbers, so ladybug infestations are extremely rare. Some people have ladybug allergies that carry mild symptoms like runny noses, watery eyes, and respiratory problems. Ladybugs are also not known to be attracted to human dwellings. Usually, if you find a ladybug inside your home, it has wandered in by accident. The only exception to this rule is that ladybugs will “overwinter” inside homes during the winter months. Overwintering is a process in which insects will seek out warmer habitats to reside in during the winter.
Ladybugs are beloved by farmers and gardeners for their appetite for other plant-eating insects. Ladybugs primarily eat soft-bodied insects like mites, leafhoppers, mealybugs, ants, and various larvae. However, their most notable benefit is their insatiable hunger for aphids, and a single ladybug can eat up to 5,000 aphids in its lifetime. They do all this while posing no threat to your garden, home, or pets.
If you see large amounts of ladybugs inside your home, especially in and around windows, you likely have an Asian lady beetle infestation. By their scientific name Harmonia axyridis, these small beetles greatly resemble ladybugs but are a highly invasive garden pest species. Introduced in the early 1900s to help control other, more harmful insects, these beetles have become a whole new problem for homeowners. Asian lady beetles congregate indoors, where they find warm, wet areas to lay eggs, and become an infestation.
Asian lady beetles are drawn to heat, bright light, and moisture, making human homes prime real estate. Usually, they will enter a house through a crack, a hole in a window screen, or even inside a houseplant. Once inside, they will find a cozy spot, usually in the corner of a window or along a baseboard, and release a potent pheromone that will attract more. Soon, that window or baseboard will be crawling with them as they reproduce quickly, en masse. These beetles can produce up to 1,000 eggs that hatch in only five days and grow to adult size in 15-20 days. Because of this rapid multiplication, sudden infestations catch most homeowners off guard; it goes from one or two “ladybugs” to thousands in just a few weeks.
Thankfully, besides being unnerving in large numbers and a general nuisance, Asian lady beetles are entirely harmless. They’re slightly more aggressive than ladybugs and are known to bite, but they don’t do so often, and these bites are more of a harmless pinch. These beetles also pose no threat to your home or garden, as they do not damage wood, cloth, paper, or carpet. One caveat is that these beetles can produce a foul, chemical-smelling liquid when threatened, stressed, or killed. This process is called “reflex bleeding” and is a deterrent for predators; this liquid can stain light-colored material, and its smell can linger for some time.
Superficially, Asian lady beetles and ladybugs are very similar, but there are distinct differences between the two:
Unfortunately, lady beetle infestations are challenging to spot early. Due to how quickly they reproduce, it doesn’t take long for a home to have several thousand of them running around; by this point, it’s apparent you have an infestation on your hands. Discovering these nasty pests before they multiply is tricky, as there are usually only a few floating around before their population booms. To spot early infestations, you should check the common places in your home lady beetles like to gather, especially during the fall months. Asian lady beetles will attempt to invade your home as they seek shelter before temperatures drop. Common locations lady beetles are known to nest are as follows:
Another common way of identifying lady beetle infestations is small, yellow-orange streaks across lightly colored materials. This streaking is most common on white-colored walls, windowsills, curtains, lampshades, and even furniture. Lady beetles leave these stains through their secretions of pheromones and reflex bleeding.
Ladybugs and lady beetles get into a home the same way all insects do, with small openings from the outside. Many of these entryways can be extremely difficult to spot and are easy to overlook. However, don’t underestimate an insect’s ability to squeeze through even the tiniest cracks and crevices. Some of the most common entry points for insects are:
Lady beetles are also known to hitch a ride into homes on plants. This is most common when a homeowner brings a plant into their home from their garden; this plant will either carry a lady beetle or host a clutch of lady beetle eggs. Once inside, they hatch, grow, and populate.
Due to their massive size, lady beetle infestations can feel like daunting obstacles for a homeowner. Even worse, completely clearing them out can be particularly challenging. This is because many common tactics for removing them, such as swatting, smashing, or even sweeping, result in reflex bleeding. Furthermore, it doesn’t take many lady beetles to create a whole new infestation, so you will need to remove them all to be pest-free. However, some effective strategies for proper pest control can give these bothersome beetles the boot.
The easiest way to remove large swarms of lady beetles is to vacuum them up. If you have an older bag vacuum cleaner, all you need to do is vacuum them up, take the bag outside, and release them (preferably far away from your property.) Alternatively, if you don’t have a bag vacuum cleaner, you can tie a sock or pantyhose to the end of and into the vacuum’s hose while securing it with a strong rubber band. This way, when you vacuum them up, they will be sucked into the sock and kept out of the internals of your vacuum. All you have to do then is tie up the sock and take them outside.
Dish soap is another way to remove large swarms of lady beetles. Either mix dish soap with water and douse them with a spray bottle or mix a large bowl of water with dish soap. This mixture is caustic to them, and the soap makes it difficult for them to escape.
The best solution to an infestation is proper prevention and making sure they don’t get inside in the first place. Ensure all cracks, holes, gaps, and other openings in your walls, siding, and foundation are properly sealed. Foam sealant and caulk are great for cracks and crevices, creating an airtight seal. Homeowners should also ensure that all gaps in window screens and screen doors are patched or replaced, as well as replacing your weather stripping.
One of the most important preventative measures for deterring lady beetles is keeping a clean and trim lawn. An overgrown and unattended lawn will result in higher insect populations in and around the home; this means more prey for lady beetles and more lady beetles inside your house.
There are many repellents homeowners can use to eliminate and prevent lady beetle infestations. Alongside many commercial insecticides, homeowners can use any of the following:
Ladybugs are a helpful, non-intrusive species of beetle that kills harmful, planet-destroying pests. On the other hand, Asian lady beetles are themselves a pest that can quickly invade a home and turn into an infestation. While similar, ladybugs and Asian lady beetles are distinguishable and possess distinct differences in appearance and behavior. Understanding these differences is essential in keeping a pest-free home while still enjoying the many benefits of having ladybugs in your lawn and garden. The most effective way to stop an infestation is to prevent it from ever happening. You can achieve this with proper home and lawn care and several natural repellents if the situation warrants it.
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