Crop & Pest Report


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Clover Mites - A Nuisance in Homes (5/10/12)

Do you see small dots moving around on the inside of your window sill or climbing up the sides of house on the sunny-side (south or west)? You are not seeing things, but these are probably tiny clover mites called Bryobia praetiosa.

These reddish-brown mites are cool-season mites and are active in spring and fall. They can be identified by their front legs that are about twice as long as the body and the other legs. Thousands of clover mites can invade a house through cracks in foundations or by crawling through the screens. They do not bite or sting people or pets. When crushed, they cause a blood-red spot that may stain the walls, curtains or carpets. 

Clover miteClover mites feed on the plant juices of turf grasses, clover and even certain trees or shrubs. They are more common in newly established lawns or older lawns that have been heavily fertilized. For control, caulking any cracks or opening in the foundation will help prevent mites from getting into the house. A grass-free zone of 18-24 inches around the base of the house also can be an effective barrier against mites. Landscape rocks are not effective barriers to clover mites. Some plants are not attractive to clover mites including zinnia, marigold, salvia, rose, chrysanthemum, petunia, juniper, spruce, arborvitae and yew. These plants can be planted in the grass-free zone. Insecticides registered for mite control and outside use around the house can be used as a perimeter treatment around the base of the house to reduce mite infestations. Insecticide should be sprayed 2-3 feet up the side of the house and 2-3 feet out from the base. Applications should be concentrated in the area where mites are entering the house. A vacuum or damp rag can be used to remove mites from inside the house. 

Janet J. Knodel

Extension Entomologist

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