Clover Mites

Clover mite
(Photo: Rayanne Lehman, PA Dept. of Ag)

You may soon begin seeing tiny, bright red insects crawling around on the sunny sides of buildings, windowsills, retaining walls, etc. Most likely, the insects are clover mites. They can become a problem in early spring when they invade structures in large numbers. Clover mites are tiny (1/30-inch long), red to reddish-brown, oval-shaped mites. Clover mites, as do other arachnids, have 8 legs. They hold the front pair of legs straight out in front of the head (see photo at left). Many people actually mistake this pair of legs for antennae.

Clover mites do not bite nor do they burrow under the skin. They are strictly plant feeders. Hosts include grasses, clover, and dandelion, to name a few. Most heavy outbreaks occur in the early spring, especially around heavily fertilized lawns. In heavy infestations, the mites may invade structures and can leave a reddish-brown stain if crushed.

Placing gravel around the structure can 

help prevent clover mite invasions.   

(Photo: M. Waldvogel, NCSU)

Control. Effective control means preventing entry into buildings in the spring. Exterior cracks around doors and windows or holes in the foundation should be caulked. An 18”-24” grass and weed-free zone around the structure’s perimeter can greatly reduce the number of invading clover mites (see photo at right). Many plants are actually unattractive to clover mites, including geranium, marigold, zinnia, salvia, rose, chrysanthemum petunia, juniper, spruce, yew and barberry. Planting these non-attractive plants in the weed-free zone will help reduce the number of clover mites around the structure. You may also contact your county Cooperative Extension Center for advice on proper fertilization of lawns. For extremely heavy infestations, it may help to treat a 5-10 foot wide area of ground along the foundation, as well as an 18-24 inch wide vertical band of the foundation wall with an appropriately labeled residual liquid insecticide. Keep in mind that you will be applying a broadcast spray in this case, so you must follow proper notification procedures.

 

The application of insecticides indoor for clover mites is not warranted. There is no specific target site and excessive indoor applications are potentially harmful to children, teachers, and staff. Clover mites are not a true “emergency” and so any spraying indoors would require that you follow the 72 hour notification policy. Simply use a vacuum cleaner to collect any mites found indoors. Care should be taken not to crush the mites. The vacuum bag should be sealed in a disposable plastic bag before throwing it away.