Multicolored Asian lady beetles

Quick facts

  • One species of lady beetle, the multicolored Asian lady beetle (MALB) has become a nuisance in Minnesota. 
  • They cluster around buildings in large numbers during fall in search of protected sites for the winter
  • Control measures should only be used to prevent entry of Asian lady beetles indoors.
  • Other lady beetle species feed on aphids and other soft-bodied insects that can damage plants in agricultural crops, gardens and landscapes.
  • These are beneficial insects to farmers and gardeners.

    Multicolored Asian lady beetle, Harmonia axyridis (Pallas) is also known as Asian lady beetle, Halloween lady beetle, and Japanese lady beetle.

    How to identify Asian lady beetles

    Adult beetles

    Two orangish beetles; one with several black spots on its wing covers and one without. Both have a black M-shaped marking behind its head.
    Multicolored Asian lady beetles. Notice the black M-shaped marking behind the head on both beetles.
    An orange beetle with a black head and few faint black spots
    Multicolored Asian lady beetle

    The multicolored Asian lady beetle looks very similar to other lady beetles but is generally larger, about 1/3-inch long.

    • It can be seen in a range of colors, ranging from orange to yellow to red or even (rarely) black.
    • This beetle typically has 19 black spots which can vary in appearance from well-defined to no more than faint traces on its wing covers.
    • These lady beetles may also have fewer than 19 spots and some may have no spots at all.
    • Look for the clear black 'M'-shaped marking behind its head, to correctly identify the multicolored Asian lady beetles.
    • The 'M' can look thick, thin or even broken in appearance.

    Larvae

    A black caterpillar like insect, with spines all over the body
    Multicolored Asian lady beetle larva feeding on aphids
    A black caterpillar like insect with 6 black feet and two orange stripes, one on each side
    Multicolored Asian lady beetle larva feeding on aphids
    • The immature larvae are alligator-like, and appear similar to other lady beetle larvae.
    • Larvae are blue to black with two orange stripes, and rows of small, spines on their bodies.

    Asian lady beetle as a household pest

    Multicolored Asian lady beetles can be a nuisance when they occur in large numbers inside homes.

    • They do not infest wood, destroy fabrics, eat food or damage other property.
    • These lady beetles cannot sting and do not carry disease.

    Some concerns with multicolored Asian lady beetles are:

    • Some can bite hard enough to break human skin, causing minor, short-lived discomfort. These bites happen when the beetles are searching for moisture or food.
    • They can secrete a strong-smelling yellowish liquid from the joints of their legs. This liquid can stain light colored surfaces.
    • Exposure to dead lady beetles in buildings can cause allergic reactions in some people.

    Asian lady beetle as a garden pest

    Several orange beetles with black spots feeding on a bruised red apple
    Multicolored Asian lady beetles infesting an apple

    Asian lady beetles are common in wooded areas, agriculture fields and home gardens. When they run out of their preferred food source (aphids), these lady beetles fly to another food source, often fall-ripening fruit such as grapes, apples and fall raspberries.

    • These insects only infest apples that already have wounds, such as holes made by birds or other insects.
    • Ripe or nearly-ripe apples may be seen with fairly large cavities in them and a number of lady beetles inside eating the apple’s flesh.
    • Picking up fallen apples and removing damaged apples still on the tree will help reduce the number of lady beetles on apple trees.

    VedgEdge has more information about Asian lady beetle as a crop and garden pest.

    How to protect your homes from lady beetles

    Preventing entry is the most effective step.

    • Check the outside of your home for spaces and cracks that may allow insects easy entry.
    • Lady beetles can fit through openings as small as 1/8 inch in size.
    • Make any necessary repairs by the end of September.
    • Seal cracks and spaces around doors, windows and fascia boards. Check for gaps and cracks where different materials meet, such as brick and wood siding. Seal cracks with caulk, such as silicone, elastomeric latex or silicone/acrylic.
    • Seal areas where cable TV wires, phone lines, and other utility wires and pipes, outdoor facets, dryer vents and similar objects enter buildings.
    • Seal with caulk or for larger spaces use polyurethane expandable spray foam, steel wool, copper mesh or other appropriate sealant.
    • Repair or replace damaged window and door screens.
    • Repair or replace damaged screens in roof and soffit vents, and in bathroom and kitchen fans.
    • Install door sweeps or thresholds to all exterior entry doors. Install a rubber seal along the bottom of garage doors.
    • This will not eliminate all lady beetles but it will reduce the number entering buildings.

    Using pesticides

    Use a residual insecticide barrier to limit the entry of lady beetles. Apply in late September or early October, before insects begin to enter buildings. Some examples of effective active ingredients in pesticides are:

    • bifenthrin

    • cyfluthrin

    • cypermethrin

    • deltamethrin

    • permethrin

    Apply around doors, windows and roof lines. Pay particular attention to the south and west sides where the insects are most numerous.

    You may want to contact a structural pest management service.

    CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Remember, the label is the law.

    When lady beetles are seen indoors

    Spraying pesticide sprays indoors is not effective. Once lady beetles move into wall voids in the fall there is no way to prevent them from emerging later during winter or spring.

    When you find lady beetles in your home, remove them with a vacuum.

    • Lady beetles are not automatically killed when they are vacuumed.

    • Change the bag frequently to prevent lady beetles from escaping and to minimize their smell.

    You may use a knee high nylon stocking that has been inserted into the extension hose and secured with a rubber band. As you vacuum, the lady beetles are captured in the stocking.

    • Remove the stocking after vacuuming, so the captured beetles won't escape.
    • Use the rubber band to close the stocking and throw it away.
    • The stocking may also be reused after discarding the contents.

    More information about Asian lady beetles

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    Jeffrey Hahn, Extension entomologist

    Reviewed in 2018

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