Clover Mite

The common name comes from clover being the preferred host plants of this mite. This is a nuisance pest which sometimes invades structures by the thousands, primarily in the autumn. It is distributed worldwide and is found throughout the United States.

Recognition

Adults are about 1/64 inch long. Body oval, soft, dorsoventrally flattened. Color often dark red, also olive green or rusty brown. Dorsum with two shields weakly defined, reticulate, and not protruding over mouthparts; porpodosoma with four pairs of hairs and bases fused, separated from ventral rostrum, chilicerae long, recurved, and whiplike; palpus five-segmented, with distinct tumb-claw process. Ocelli present on propodisoma. Antenna two in number, located behind cheliceral bases, absent on hysterosoma. Legs with first pair very long, about twice length of second pair, held forward like antennae; tersi with padlike empodia and claw terminating in a pair of tenant hairs. Genital opening transverse. Plant feeders. Note that there are 15-20 different morphological forms of the clover mite.

Habits

Clover mites are plant feeders only. They feed on some 200 different plant species including trees, shrubs, flowers, grass, and agricultural/garden crops. Around structures they show a preference for heavily fertilized grass/lawns.

The spherical red eggs sometimes can be seen on foundation walls and/or in foundation cracks. They also are laid on vegetation. Sometimes in the autumn the number of eggs can be large enough to give the surface they are on a fuzzy red appearance.

The invasion of structures by enormous numbers of clover mites usually occurs in the autumn as the vegetation dies, with mites numbering in the hundreds of thousands. In Pennsylvania, the greatest number of structural invasions occurs in April, with May second. Springtime structural invasions usually are associated with new mulch being applied to plant beds and shrubbery around the foundation. Invasion typically is through cracks around windows and doors or through masonry cracks. They will come up behind siding until an entryway is found.

Clover mites are active during times of cooler weather and become dormant/inactive during hot weather. In Illinois and Pennsylvania, they become dormant in May and remain so until September. In the eastern United States, these mites can be found in infested homes from November until May or June, with nuisance activity highest during the spring.

These mites will leave a reddish spot/smear/stain if crushed. This can cause problems on wallpaper, drapes, window shades, stuffed furniture, carpets, etc.