It's that time of year that your home may be invaded by insects nicknamed “Halloween Beetles” because of their pumpkin-orange wings covered with black spots and the time of year they can become noticeable. In spite of their curious color, the multicolored Asian lady beetle can stain the inside of your home and give off a foul odor.

Experts with The Ohio State University College of Food, Agricultural, and Environmental Sciences are offering tips on what to do about the multicolored Asian lady beetle that can swarm and sometimes get into homes.

Contrasting colors and seasonal appearances of the multicolored Asian lady beetle have given rise to a number of other common names for this lady beetle including "Harlequin ladybird" and "Halloween lady beetle" because some adults are a pumpkin yellow-orange color and large populations often occur in late October coinciding with Halloween festivities.

Lady beetles, sometimes called ladybugs or ladybird beetles, generally are beneficial predators that consume aphids, scale insects, and many other pests that injure plants in gardens, landscapes, and agricultural settings.

However, the multicolored Asian lady beetle has several bad habits. Their negative behavior and impacts can be separated into four general categories: interior pest, outdoor nuisance pest, fruit and fruit products pest, and a competitor to other predators, including native lady beetles.

The bug may also accidentally move into homes and other buildings in the spring. The winter survivors intend to leave their protected hibernation sites to seek food in the outdoors. Beetles that spent the winter in exterior wall voids, attics, and other unheated areas within buildings may crawl into rather than out of buildings.

The movement of large numbers of MALB into homes and other buildings, both in the fall and spring, causes them to become a significant indoor pest.

The confused and disoriented invaders fly around inside structures finding their way into food and drinks, alighting on hands, arms, and other parts of the body, sometimes entering ears and mouth.

Collections of dead multicolored Asian lady beetle bodies on window seals are unsightly and bodies on floors "crunch" underfoot.

When lady beetles are disturbed, they defend themselves by exuding a yellow-orange body fluid, which has a foul odor and can permanently stain walls, drapes, carpeting, etc.

Lady beetles are predators and are capable of biting, although this is a rare occurrence. However, the multicolored Asian lady beetle appears to be a more aggressive lady beetle compared to native species.

There have been consistent reports of the Asian species biting humans, particularly when beetles become trapped between skin and clothing, such as beneath shirt collars. The beetles are not capable of breaking the skin, and they will not spread diseases with their bites.

Allergic reactions are a more serious issue. Allergenic responses to defense chemicals in MALB blood have been documented with clinical manifestations, including rhinoconjunctivitis, asthma, welts, and angioedema. Sensitivity is not related to a person's age or predisposition to allergies-an MALB allergy can appear in individuals who have never suffered allergic reactions to cats, dust mites, cockroaches, etc.

Outdoor Nuisance Pest

Although it has been a number of years since large outdoor swarms of multicolored Asian lady beetles occurred in late autumn in Ohio, reports from the 1990s described some extreme nuisance behavior. This included large numbers of beetles getting into food and drinks during outdoor gatherings such as sports tailgating events, beetles landing on people and sometimes crawling into mouths and ears, and large numbers of beetles congregating on and around outdoor porch furniture. The insects were sometimes so numerous that they appeared to be "raining" outdoors or swarming like bees. Such negative outdoor experiences are expected to return if MALB populations rebound in Ohio.

Fruit and Fruit Products Pest

The multicolored Asian lady beetle has proven to be a more serious pest of fruit products, particularly grape juice and wine made from the juice. The problem is associated with the beetle's defense chemical. Although low concentrations of this chemical are also found in a wide range of fruits and vegetables, including grapes, where it is a component of agreeable flavor profiles, the concentrations due to MALB impart a detectable and distinctly unpleasant taste, which is known as "lady beetle taint."

Management Options


The best management recommendation is to prevent MALB from entering buildings in the first place. Take measures to exclude these lady beetles before late autumn when they begin to seek overwintering sites in structures. Here is a check-off list of effective pest-proofing tasks:

MALB and many other insects can slip through gaps of about 1/8 inch. Seal cracks around windows, doors, siding, utility pipes, and other openings. Use weather stripping or a good quality silicone or silicone-latex caulk. Larger gaps can be sealed with urethane foam, glass wool or stainless steel wool, etc.

Install tight-fitting door sweeps or thresholds at all exterior entry doors. Here's a useful inspection tip to discover worn door sweeps and poorly fitted door jams: turn off outdoor and indoor lights at night and remain indoors while someone shines a flashlight beneath and around doors to reveal gaps.

Inspect and replace worn garage door seals. Rubber seals work better than vinyl seals in cold weather.

Attics are a favored MALB overwintering site as well as a route for beetles to enter the living areas of a home. Inspect and repair or replace damaged soffits. Install insect screening (20-mesh maximum) over attic vents and fan exhausts (e.g., kitchen and bathroom) that vent into attics. Fashion insect screening "cages" to fit over can lighting fixtures or other openings into attics.

Repair or replace damaged or loose-fitting door and window screens.

These pest-proofing tasks provide the added benefits of preventing other nuisance pests from entering homes and reducing heating and air conditioning costs.

Removal Using a Vacuum Cleaner

A nylon stocking inserted into a vacuum cleaner extension wand creates a handy bag for capturing lady beetles and prevents the beetles from passing through the vacuum's suction impeller.

Remember that lady beetles use their foul-smelling "blood" as a defense against predators. Swatting, smashing or crushing lady beetles will release this odor, and MALB body fluids can leave a permanent stain on carpets, curtains, walls, etc.

An effective way to quickly collect and dispose of large numbers of MALB in a home is to use a "fan-bypass" vacuum cleaner (e.g., shop-vac). This type of vacuum cleaner has the vacuum impeller (fan) positioned after a collection container or bag; refuse is collected in the bag or container without passing through the impeller. Do not use a "direct-fan" vacuum cleaner. This type of vacuum cleaner has the vacuum impeller positioned in front of the collection bag or container close to the vacuum opening.

Refuse must pass through the impeller before being collected, turning this type of vacuum cleaner into a horrible beetle-blender! Beyond releasing the beetle's foul odor, there have been reports of lady beetle body fluids fowling vacuum cleaners to such an extent that they become unusable.

If a fan-bypass vacuum cleaner is not available, a direct-fan cleaner can be used with a simple modification. The beetles can be captured inside a knee-high nylon stocking that has been inserted into the extension hose or wand and secured in place with a rubber band. As soon as the vacuum cleaner is turned off, be sure to remove the stocking so that the captured beetles cannot escape. As you remove it, the rubber band closes around the stocking, effectively "bagging" the lady beetles. You can then discard the stocking with its contents.

Indoor Trapping

Thus far, no MALB traps have been developed that rely on chemical attractants. However, like many insects, MALB is attracted to ultraviolet light or "black light," and there are a number of commercially available blacklight traps that can be used indoors either directly or with minor modifications to collect MALB. Do not use blacklight traps that utilize an electrically charged grid to kill insects such as a "bug zapper." The electrical charge causes the beetle's body fluids to flash to steam, and the resulting exploding beetles can spray foul-smelling, staining fluids over a wide area.

It is unproven whether traps can solve large indoor MALB infestations. In homes, traps might be useful in dark attics or crawl spaces. Depending on the level of infestation, numerous traps may be necessary: one in each room or a single trap may have to be moved to different problem areas. The effectiveness of traps may depend on the number and position of traps in structures, but such research has yet to be reported.

The Role of Insecticides

Insecticides may be used to supplement other control efforts, particularly if you have encountered persistent, large MALB infestations. However, read the label before considering whether to use or apply an insecticide. The label is the law! It is important to precisely follow label directions. To do otherwise is unlawful and could result in significant health risks. Insecticides should be applied only to specific sites in order to minimize chemical exposure. Many insecticides are labeled for use only by certified, licensed applicators that have received specialized training on the use and disposal of insecticides. These insecticides should not be applied by unlicensed homeowners.

Exterior insecticide treatments involve an appropriately labeled repellent, long-lasting insecticide to help prevent pest entry. The insecticide typically is applied to outside walls and siding, as well as around eaves, attic vents, roof overhangs, and doors and windows. Pre-test a small area to ensure that the chemical treatment does not cause staining or discoloration. It may be a good idea to enlist the services of a professional pest control company licensed to chemically treat the building exterior.

Timing is very important, and outdoor preventive treatments should be done prior to overwintering attempts by the lady beetles. If the chemical is applied after the first cold snap of autumn, lady beetles that already have congregated indoors will be unaffected. If applied too early, the chemical may degrade and lose its effectiveness against the lady beetles.

In Ohio, an exterior chemical application during late September or early October should work best as a preventive treatment. A second application may be needed if the chemical begins to degrade over a prolonged season.

Do not use insecticides to treat landscapes surrounding infested homes and buildings in an attempt to control lady beetles. Lady beetles are attracted to structures from distant areas and thus are unlikely to be impacted by the insecticides. General insecticide sprays also kill beneficial insects, thereby causing outbreaks of other plant-infesting pests.

Insecticides used indoors against MALB have very limited impact because large numbers of these insects typically hide in inaccessible areas. If an insecticide is used indoors, it should be limited to specific locations for relief of persistent and large lady beetle infestations. Residual pyrethroids appear to be the most effective, but only when the beetles are sprayed directly or when they crawl over treated surfaces. Products that contain a residual pyrethroid as the active ingredient may be marketed by different companies under a variety of trade names.

Do not use any type of aerosol fogger or "bug bomb" in an attempt to control MALB. Such chemical treatments are not warranted because they do not affect the majority of lady beetles that are hidden. The active ingredient has very limited effectiveness against lady beetles, and humans are unnecessarily exposed to chemicals in indoor environments. Furthermore, such treatments can cause additional, persistent indoor pest problems because scavenging pests (i.e., ants, dermestid beetles [carpet beetles and larder beetles], etc.) are attracted to feed on accumulated dead insects.