Editor’s Note: This article was reprinted with permission from Pinto & Associates.
Most people misidentify clover mites, expecting them to be bright red. Adult clover mites, Bryobia praetiosa, are more subdued in color, reddish-brown to greenish-brown with pale orange legs. The much larger and predaceous “velvet mite” is bright red and is often mistakenly identified as a clover mite. To confuse the issue, the 6-legged larval stage of the clover mite is also bright red. Clover mites are found throughout the world.
Clover mites can be easily confused with other small mites such as bird mites, rodent mites, grain mites or even larval brown dog ticks. Clover mites are best identified by the fact that their front pair of legs (out of four pair total) are much longer and are held forward, looking more like antennae than legs. Tiny clover mites (1/64-inch or .75 mm) look like barely visible dots, and are best seen when a group of them are moving together on a surface.
Clover mites are plant pests, feeding mainly on grasses, clover and other weedy plants found in lawns, but also on shrubs, flowers, crops and trees. Heavy populations of mites can damage or kill grass around foundations. Clover mites are active in cool weather, becoming dormant in hot weather (above 80°F/27°C). In fall, large numbers of red eggs that will hatch in spring may be seen on vegetation or on sunny foundation walls.
PEST STATUS. Clover mites may invade structures when grass dies in fall, but they are problems most often in early spring or late winter or during very cold, wet or hot weather. They can gather by the thousands on sunny, exterior walls, seeking protection under shingles or siding. Their size lets them squeeze through window screens and crevices.
New homes with lush, heavily fertilized lawns and grass planted right next to the house tend to have the biggest problems with clover mite indoor invasions. Mite problems lessen as lawns (and mite predators) become established.
Once indoors, clover mites usually die in a few days from dehydration. Clover mites do no damage and do not bite, but crushing them can leave a reddish spot on fabrics or surfaces. Control them indoors with a vacuum with a soft brush attachment.
KEY POINTS TO REMEMBER. Clover mites are seasonal nuisance invaders. An outside perimeter treatment and pesticide treatment of entry points can stop an invasion. Use a product that mentions mites on the label. The most effective long-term control calls for leaving an 18-inch grass-free strip next to the foundation. Also suggest to customers to prune back shrubs or ivy touching the walls, fertilize in fall not spring, and mow grass short.