Asian lady beetles

Fall brings about falling leaves, beautiful colors, the last of the produce coming out of the garden and multicolored Asian lady beetles. As a gardener and a farm wife, I am always battling insects getting into the house from flies to beetles and crickets to multicolored Asian lady beetles. These along with boxelder bugs are now looking for a home for the winter months. They are not a huge problem in our house but this year we are doing a little remodeling and they are helping themselves to our old entryway.

As many of us know, lady beetles mainly feed on aphids but the Asian lady beetle tends to be a little more aggressive particularly in the fall as they look for a place to overwinter. Asian lady beetles have been in the U.S. for a very long time. They were originally released in California in 196 and again in 1964-1965 for control of pecan aphids. They were released again for biological control in other states in 1978 through 1982 in southern states and eastern states. After this release, they were not seen again until 1988 in Louisiana. These are the Asian lady beetles that we are still dealing with today. Asian lady beetles have never been released in Minnesota, but in 1994, they were first sighted in Minnesota and by 2000, the insect had its foot (or wing?) in the door by this time. They are easily identified from our lady beetles mainly because they are so much larger. They can have spots or no spots. Since they are predators of aphids, primarily, when the soybeans start coming out of the field, they start looking for a place to stay for the winter. They generally also start looking for a home after freezing or near freezing temperatures. This is their signal that it is time to start moving to a better place for the winter. They will hang out in any indoor place until winter releases its grip on them. This sometimes happens mid-winter during one of our famous “January” thaws too. They do not reproduce in the house and if you start to see more of them, it is just because they are coming out of hiding.

The one thing we can agree on is that we don’t like them in our homes. If they just stayed outdoors, we wouldn’t have such a problem with them. They do not sting or carry diseases. They can bite hard enough to break human skin but they do not attack people. They smell because they secrete a strong liquid from the joints of their legs. And, there are some folks that can have an allergic reaction to them after they have died.

To make sure they don’t get into your home can be quite difficult because just opening the door to your home, can allow them in as they fly around your home. Any cracks in your home or breaks in your window screens as small as 1/8 inch can allow them to sneak in your home. Checking your home for these spaces can help to keep them from getting in but it will not eliminate their presence. You can try a residual insecticide barrier containing the following chemicals: bifenthrin, cyfluthrin, cypermethrin, deltamethrin and permethrin. Make sure to read the label and make sure the product is safe to use on exteriors of buildings. Once Asian lady beetles get inside or other insects for that matter, you best defense is your vacuum cleaner. Once you have vacuumed them up, remember that they are not necessarily killed and you should remove your canister or bag outside immediately so they do not attempt to crawl out of the vacuum cleaner. They will also make your canister or bag smell. If you want to try another method, take a knee-high nylon stocking and place it into the hose of your vacuum cleaner. Attach the stocking to the hose with a rubber band. As you vacuum, the lady bugs are captured in the stocking. Turn off the vacuum and use the rubber band to close the stocking. You can remove them back outside and keep the nylon for further use. For more information on Asian Lady beetles, the U of M Extension has an excellent publication which can be found at

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