What should I do with the orange Asian lady beetles in my house? Can I release them into my garden?
Asian lady beetles (Harmonia axyridis) are a species introduced from eastern Asia, and they also are mighty beneficial insects that prey on aphids, a serious pest in many gardens. Each day, a single adult lady beetle can eat up to 270 aphids or other small insects, and each larva will devour 600 to 1,200 aphids during its 12- to 14-day feeding period. Some of that bug-nabbing will happen in your garden, but most of the action takes place in the treetops.
Light-colored buildings near wooded areas attract the attention of thousands of Asian lady beetles in fall as the beetles look for snug spots — such as inside your home’s walls — to spend the winter. The only way to keep the lady beetles out is to seal open crevices, and keep south-facing doors and windows tightly closed when they are swarming.
In spring, most of the lady beetles in your house will leave unnoticed the same way they came in; others will leave freely if you remove screens or storm windows and open warm windows an inch or two at the top.
Should you collect and release beetles that won’t leave on their own? In terms of control of other insect pests, the number of beneficial beetles you might capture and release outdoors is insignificant compared to the outdoor population as a whole, says Ted Cottrell, research entomologist at the U.S. Department of Agriculture’s Southeast Fruit and Nut Tree Research Lab in Byron, Ga. “From a convenience standpoint, get rid of them using your most effective and easiest method — dead or alive,” he says.
The method of choice for most folks is to vacuum them up. To keep from having to change your vacuum’s bag or empty the canister, place a thin sock or knee-high stocking between your vacuum’s hose and head before quickly doing the deed. Special long-handled “bug vacuums” are great for reaching high corners — folks who think the only good spider is an outdoor spider love them.
If you’re faced with overwhelming numbers of beetles indoors, collect them at night with a light trap such as the one developed by the Integrated Pest Management team at Ohio State University. (Learn more by going to Ohio Integrated Pest Management, then click on “lady beetle information” and under the heading “Managing MALB” choose “light traps.”) This trap makes use of milk jugs and other easy-to-find materials and is designed to be hung from attic rafters.
After months indoors, Asian lady beetles are dehydrated and hungry, so you also have the option of coddling the poor wanderers until the weather warms. Asian lady beetles usually drop straight down when disturbed, so it’s easy to collect them in a wide-mouth quart jar furnished with some apple peelings and a damp paper towel, then covered with a thin cloth. Within minutes the beetles will be quenching their thirst and filling their bellies. They will be more than content in their “spa” until the weather warms up and you can release them outdoors.
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Contributing editor Barbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens. Contact Barbara by visiting her website or finding her on Google+.
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