Multicolored Asian lady beetle: friend and foe

By Eric Barrett

OSU Extension

The multicolored Asian lady beetle (MALB) is a non-native insect that came to the U.S. from Asia. The adults are named “multicolored” because they range in color from pink to orange and most shades in between.

Our new fact sheet from Ohio State suggests we’ll never know exactly how it got here — by accident or as part of a biological control program for “bad” insects. But why would someone have brought them here? Well, MALBs are voracious eaters, eating up many, many aphids per day at various life stages.

This is where the common argument over viewing them as a friend or as a foe begins. Which side you end up on usually depends on your point of view – as a farmer/gardener or as an occupant of a home where these insects invade your space in late fall through winter.

Although MALB is not quite the problem it was in the early 2000s, some homeowners are still plagued each fall by the insects’ mass search for a place to overwinter. It seems that after the first frost/freeze event of the fall, followed by a couple days in the 60-degree range, these insects begin to congregate in large numbers on the sides of buildings. This is based on the way they overwinter in their native Asian habitat.

If you have seen this problem in the past, now is the time to check your homes and buildings for areas that this beetle can use to gain entrance. Buildings that experience major invasions usually have gaps around windows and doors. These cracks need to be sealed with weather-stripping materials or caulked. The trim surrounding these structures needs to be checked and caulked if there are gaps of 1/8 inch or more in size. Extra areas to check are where the roof and house join, chimneys, and any other small space where the beetles could enter.

For farmers and gardeners, the larvae and adults are great because they eat the aphids in soybean fields and the aphids on many landscape plants. Thus, they try to encourage them as part of an integrated pest management (IPM) program. To keep these insects active, be on the lookout for the larvae. The larvae of MALBs are best described as a tiny black alligator with orange stripes and markings. It’s something good to watch out for in the yard and garden. This stage eats lots of aphids and other insects which can harm your plants.

Joe Boggs and Susan C. Jones wrote a great new fact sheet outlining both the good and bad of this insect. The fact sheet is located here:

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