Clover mites are accidental invaders that can be a temporary nuisance. These small, reddish-brown creatures with very long front legs (Figure 1) appear only as moving dark spots to the naked eye. Sheer numbers, plus the resulting red-brown stain left behind if they are crushed, make them unwelcome visitors. Clover mites are not blood feeders and will not harm people or pets, nor will they infest household products. Once inside a home or building they will soon die.
Clover mites feed on plants. They can be especially abundant in the heavy, succulent growth of well-fertilized lawns. They generally enter a home around windows or doors, so they are usually seen crawling along window sills or thresholds.
A soapy rag or wet sponge can be used to clean mites off surfaces. Wipe carefully to avoid crushing the mites and causing stains. The crevice tool of a vacuum cleaner may also be used to pick up mites. Rely on non-chemical control indoors. Do not apply insecticides to kitchen counters or other interior surfaces.
There is an increased potential for clover mites invading structures when grass extends up to the foundation. A plant bed or open area will provide a barrier that will stop many mites and provide a long term solution to persistent problems. Avoid over-fertilizing lawns; this creates situations that are ideal for mites to increase to tremendous numbers.
A barrier spray of a pyrethroid insecticide (e.g., Spectracide Bug Stop® Enforcer Overnight Pest Control Concentrate) may reduce movement of mites from grasses to patios, decks, or house walls. Use a compressed air or hose end sprayer to treat at the base of all exterior doors, garage and crawl space entrances, around foundation vents and utility openings, and up underneath siding. It may also be useful to treat around the outside perimeter of the foundation in a 2- to 6-foot-wide band along the ground and 2 to 3 feet up the foundation wall. Follow label directions.
Concrete mites (or sidewalk mites) are red velvety mites (Figure 2) that crawl over pavement, patios, foundations, and other outdoor surfaces in early summer. Occasionally, they wander indoors over floors, walls, counter tops, computer monitors, etc. When crushed they leave a red pigment stain; it is not blood.
These mites belong to a large family of free-living mites that prey on insect eggs and other tiny soil arthropods. They breed outdoors in moist, organic, vegetative environments, such as those that often occur around the foundations of buildings. The mites cannot breed indoors, nor will they bite pets or humans.
By Lee Townsend, Extension Entomologist