The Asian lady beetle (Harmonia axyridis), is a common and widespread wintertime household pest across all of Iowa and most of the United States. Large numbers of these insects invade homes during the fall and remain active over the winter, especially in late winter when temperatures warm and days get longer. Ladybugs do not feed and cannot reproduce indoors; they have not multiplied indoors although it must seem that way to homeowners who have been inundated with them.
When lady beetles stranded indoors for the winter are emerging from inside house walls, there is no control option more practical or effective than repeated vacuuming. Spraying insecticides has little or no effect. However, one alternative for homeowners unable/unwilling to pursue wintertime ladybug control via vacuuming is the use of lady beetle traps as indoor collecting devices. One available trap is essentially a cardboard box with a sticky inner covering that captures beetles that wander inside it. Although sold with a pheromone, there is no indication that the beetles respond to it. Studies in North Carolina failed to find a chemical attractant. If there are a lot of beetles in a building, some will wander in the trap and be caught.
H T Alternative Controls, P.O. Box 1546, Perry, Georgia 31069 (phone 912-988-9412 or 1-877-967-6777) advertises two models of black light traps for indoor lady beetle control. They retail from almost $100 to $125. The traps fit in a corner or against a wall so that the attracting blacklight radiates outward toward the center of the room. Both traps are effective only at night in the absence of competing light sources, but can be used during daytime if the room is completely dark and unlighted by windows or other light sources.
H T traps are not designed to kill lady beetles but rather to collect them for removal from the building. To remove beetles from the trap, simply brush any beetles into the lower container, separate the upper container and lamp from the lower container and discard the contents of the lower container by pouring them into a plastic bag. The H T 120 and 360 are designed for use only on the inside of buildings or beneath a covered porch. They are not designed for use out of doors. We have no data on the effectiveness of these traps against lady beetles in the upper Midwest.
Adapted from Kentucky Pest News , February 26, 2001 by Lee Townsend, Entomologist, University of Kentucky
This article originally appeared in the March 9, 2001 issue, p. 20.