Clover mite season is upon us and any tiny, reddish brown dots seen crawling on windows sills, walls, curtains or cupboards are probably these common accidental invaders. Clover mites live and reproduce outdoors, but are frequently encountered as a household pest in early summer and in the fall when they migrate into dwellings by mistake. They do not bite or cause any harm or damage. They are, however, an annoyance and nuisance primarily because of their presence and tremendous numbers. Clover mites feed on sap from grasses and clover, and are especially numerous in lawns with a heavy growth of succulent, well-fertilized grass.
Preventing clover mite migration into the house is preferred over removing them after they have invaded. It is also easier said than done because of their small size and large populations. It may be practical to reduce migration of clover mites by leaving a bare, grassless border or flower bed next to the foundation. Because this does not always work, I would not recommend you change your landscape plans this way unless it aesthetically suits you.
Spraying to create a 10 to 20-foot wide mite-free zone around the house is the common control. Foundation and outside walls should also be sprayed. Insecticides labeled for this use include diazinon, Isotox, kelthane, and malathion. Application should be made as directed on the label and repeated in 1 to 3 weeks if necessary.
I suggest using a vacuum cleaner to remove mites from indoor surfaces. Wiping and crushing mites usually creates an undesirable brown stain.
This article originally appeared in the April 28, 1993 issue, p. 52.