23 February 2005
Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580 fax: 434.872.4578
Usually the cold winter days of February provide little arthropod entertainment but once in awhile we get a nice warm day to bring out some of our tiny friends for some fun in the sun. One that drew some attention on the sides of our houses and on our windowsills this month is the clover mite.
Clover mites are common in and around our houses. Although most noticeable in the fall and the spring, they sometimes make an appearance on sunny days in the winter. These mites are not insects. Because they have eight legs they are members of the arachnid class of arthropods along with the spiders, daddy longlegs, and ticks, among others. Their front pair of legs are longer than the others, protruding forward near the head and sometimes mistaken for antennae. As one caller described them, they are slightly smaller than the head of a pin with a reddish or reddish-brown body. When the mites are crushed, they leave rusty-red smears.
Clover mites do no damage to houses or their occupants. They feed primarily on the lawn where they suck sap from grasses, clover, and other plants. In the fall they sometimes gather in large numbers on walls, windows, tree trunks, and other outside surfaces where they seek protected hiding places. They crawl into cracks around windows or in foundation walls and under siding, shingles, or shakes. This activity often leads many of the mites into houses where they can be seen on windowsills, walls, and other things nearby. These mites are usually found congregating on the sunny side of the house.
Cold weather sends the mites into hiding to seek shelter. With the beginning of warm weather, the mites become active again and ultimately return to the lawns to feed.
Mites in the house are very difficult to control with any of the chemicals that are safe to use in houses. Vacuuming or wiping them up with a damp cloth is probably the simplest way to clean them up. Dispose of the vacuum bag after collection. Mites can escape from the bag in the vacuum.
The best answer to the problem is to prevent the mites from entering the house by creating a barrier of cultivated soil next to the foundation. Mites do not readily cross loose, clean cultivated soil; therefore, a band approximately 1824 inches wide all around the house, especially on the south/southwest sides, kept free of grass, would be an excellent deterrent. For decorative purposes, this strip may be planted to annuals, perennials, or shrubs, but in such a way that mites cannot bridge across the barrier. This bare strip can be planted with flowers such as geranium, zinnia, wallflowers, marigold, salvia, rose, chrysanthemum and petunia, or shrubs such as juniper, spruce, arborvitae, yew or barberry, which are unattractive to these mites, deterring buildup and migration. The soil around such plantings should be kept cultivated and free of grass, weeds, and fallen leaves. Landscape rock will not act as a barrier to clover mites. An application of pea gravel in the strip will also discourage mite invasion. To further deter the mites, be sure to seal cracks and gaps or other points of entry with caulking compound, putty and weather stripping around foundations, windows and doors. Use tight fitting screens on windows and doors.
The Piedmont Master Gardener Association is presenting their Spring Garden Lecture Series on Wednesday evenings for the next five weeks. The topic this week is Organic Gardening. Please call the Charlottesville/Albemarle Extension office at 872-4580 for more information.
On March 4 in Warrenton Virginia Cooperative Extension is presenting a horticulture conference featuring presentations on topics such as organic practices and certification, how to start a horticulture business, marketing off the beaten path, and bramble and blueberry production. Please call the Charlottesville/Albemarle Extension office at 872-4580 for more information.
For more information about landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.