What Are the Tiny Red Bugs on Concrete?

The mites tend to live in large colonies and feed on flowers, grasses, plants and vegetables. While they do not pose a threat to humans, they often become a nuisance to homeowners when they attempt to gain access by hanging around windows and doors, leaving red-colored stains on carpeting and doors when crushed. They may be controlled by applying an insecticide within 15 feet of the structure.