To prevent future ladybug infestations, use foam sealant and other products to close up cracks and crevices where ladybugs enter. The most important areas to watch are parts of structures that receive lots of afternoon sun. Studies show that Asian ladybugs are attracted to illuminated surfaces, including those lit by afternoon sun, which tends to appear on the southwest corner of structures in the United States. Ladybugs also flock most to areas of light and dark contrast. Such areas include those spots around windows edged with lighter trim the rest of the building.