Clover mites are very tiny arachnids that live and reproduce outdoors, but are frequently encountered as a household pest during the springtime when they migrate onto and into dwellings by mistake. They are only 1/64th inch long, soft, oval, and flattened from top to bottom. They vary in color from rusty brown to dark red. A distinguishing characteristic is the very long pair of front legs that extend forward like antennae.
Clover mites are harmless. They cannot bite or sting; they do not infest stored foods; they cannot attack the house structure and furnishings. They are an annoyance and nuisance because of their presence and tremendous numbers. Clover mites reproduce outdoors. Every mite seen indoors has wandered in from outside.
Clover mites are plant feeders only. They feed on sap from grasses and clover, and are especially numerous in lawns with a heavy growth of succulent, well-fertilized grass. They do not cause any apparent harm to turfgrass.
In some situations it may be practical to attempt to reduce the migration of clover mites into the house by removing the turfgrass and leaving a bare strip 18-24 inches wide next to the foundation. This technique is not always successful, as the clover mites may migrate over wood chip and rock mulches and through flowerbeds.
The traditional control for clover mites is to apply an insecticide spray as a chemical barrier around the house. Spray the bottom of the foundation, the crevice between the foundation and the ground and the lawn for a distance of 6 to 10 feet out from the foundation. Insecticides labeled for this use include diazinon, Isotox, kelthane, and malathion. Read and follow label directions. Repeat after 2 weeks if mites persist. Successful chemical control requires a very thorough treatment. Plan to use 2 to 4 gallons of spray for each 1,000 square feet. You may prefer to hire a professional for this application.
Clover mites already indoors can be removed from surfaces with a vacuum cleaner. Avoid wiping the clover mites as crushing them often creates an undesirable and durable brown stain. Household insecticide sprays containing pyrethrins can be used for short-term, contact control of wandering mites.
This article originally appeared in the April 21, 2000 issue, p. 37.