Clover mites

http://extension.missouri.edu/p/g7358

Clover Mites

Each spring in the DC/Maryland area clover mites appear on the exterior of structures. It is likely that these tiny red mites have over wintered in cracks and crevices of the building. They are usually most numerous on south to west faces of a structure and rarely numerous on the north side. Typically, the mites come from the ground and crawl up the side of an office building or residence, but if there are planters or moss on the roof, balcony or deck, large numbers of mites are possible in the upper levels.

Operating windows (windows that open) are rarely effective at keeping clover mites out even when they are closed. These tiny mites can usually find an opening around the edges where the window opens and gain access to the interior.

If your building has fixed, non-operating windows and clover mites are getting inside there is likely an installation flaw. Sealed systems are designed to exclude things even as small as clover mites. The caulking or sealing system around the windows is defective if clover mites are getting in. If the mites appear in areas near doors or other wall penetrations, they probably entered through small openings even if the door or penetration appears closed or sealed.

Other Key Clover Mite Points:

1. Clover mites do not bite humans. They are plant feeders, usually feeding on grass, and will not reproduce indoors.

2. Pesticide treatment is of little value indoors. The mites can be removed by vacuum and they will die in the bag or sticky traps or water traps can be placed on windowsills to capture the mites. Left alone, most mites will die within 48 hours indoors unless they find a very moist environment.

3. Avoid the urge to squash a clover mite. Their body fluids can stain the surface they are on when squashed.

4. Pesticide treatments on the exterior are generally effective in quickly reducing the numbers of mites, but total elimination with one treatment should not be expected.

Long Term Solutions

Although caulking or sealing obvious cracks or holes in a structure will help reduce clover mites, it will not usually stop them totally from entering a structure with operating windows. If you have fixed windows and the mites are getting in, the window system should be evaluated to determine how the mites are getting in and if a cost effective repair is possible. In either case, clover mites are usually greatly reduced if an 18 to 24 inch gravel barrier is installed around the perimeter of the building.