October Animal - Asian Multi-colored Lady Beetle
Dennis Ferraro, UNL Extension, is also the resident herpetologist at the School of Natural Resources. Dennis writes timely articles on animals that you might see on your acreage in Nebraska, ranging from mammals to insects. Some you may want to encourage, while some, like this month's feature, you may want to discourage!
Several of the common species of lady beetles (ladybugs, if you prefer) found in Nebraska will wander indoors during the fall. This is a distinctive and annoying trait of the Asian Lady beetle, a relatively new species imported to the United States from eastern Asia.
The “multicolored Asian lady beetle” has become common in many areas of eastern United States, including Nebraska. This ladybug is used as a natural control and therefore a beneficial inhabitant of the landscape. They can also be an obnoxious household pest in those areas where they have become well established and abundant.
Asian lady beetles, like boxelder bugs, pine seed bugs, and elm leaf beetles, are accidental invaders. Accidental invaders are “outdoor” insects that become a nuisance by wandering indoors during a limited portion of their life cycle. Accidental invaders do not feed or reproduce indoors. They cannot attack the house structure, furniture, or fabric. They cannot sting or carry disease. Lady beetles do not feed on people though they infrequently pinch exposed skin. Lady beetles may leave a slimy smear and they have a distinct odor when squashed.
As with other accidental invaders, the most effective management option is to prevent invasion by sealing cracks, gaps, and openings on the outside of a building before the beetles wander in during early fall. Application of synthetic pyrethroid insecticides such as deltramethrin to the outside of buildings may prevent pest entry. Treatment must be applied before the beetles begin to enter to be effective, typically mid to late October. Actually, it is best to apply the pesticide at the same time the insects are entering. This may be 2 -3 applications over the month. These insects die quickly with residue sprays.
Most retail insecticides usually do not provide satisfactory prevention yet will cause control on physical contact. All the ladybugs you see throughout the winter crept into the walls of the structure in October. They do not feed or reproduce during the winter and will leave the structure in late April. The main control strategy during winter and spring should be to sweep or vacuum them as you see them. Sprays around the exterior of the structure in the spring may cause them to stay in the walls and not leave the structure.