The last warm days of the fall brings swarms of ladybugs. They invade houses, seeming to get through every tiny space. Not 10 or 20 – hundreds. They are an invasive species –the Asian Lady Beetles – up to 22 spots on an orange back with a distinct “m” on their pronotums. Native to China, they were introduced in 1988 to control aphids. I don’t know if that worked but they did displace and destroy the three species of ladybugs native to Blackstone Valley – Parenthesis Ladybugs, the Convergent Ladybug (most common) and the Nine-Spot Ladybug, now an endangered species.
Asian Lady Beetles, while carnivorous, do not prefer human flesh but they will bite. They are a major nuisance, finding their way into everything. If crushed or vacuumed up, they release a foul odor and leave spots on objects.
So how do we bolster the populations of native Ladybugs and send the Asian Lady Beetle packing? There are sprays and dusts available from commercial sources that will prevent the Asian Lady Beetle from entering the house. Non-toxic methods include traps placed near windows and other entry points that use lures to attract and trap the insects. Caulking cracks, installing weather stripping and repairing broken screens are all useful solutions that will also reduce energy bills.