Issue 8, June 14, 2013

Red Mites

Little red mites are common this year in mulch and damp soil. These mites are bright red with long, obvious red legs. Landscaping crews are probably seeing them and being asked about them by clientele. As the weather warms and the mulch dries, they are moving into buildings. They are a nuisance indoors by their presence, but do not bite humans.

These mites appear to be in the family Trombiculidae, which includes the chigger. Chiggers are one species of predatory mite in this family that feed on mammal fluids as larvae. Chigger larvae are red and about the size of a pinpoint, being almost microscopic. Older stages of chiggers feed on other mites and do not attack mammals. The larvae of other mites in the family are predatory on other mites.

Mites go through three stages of development. They hatch as six-legged larvae that molt to eight-legged nymphs once they have fed. After feeding and growing, the nymphs molt to eight-legged adults. The use of larvae and nymphs for these stages are familiar as they are terms for immature insect stages but are confusing as nymphs are the immatures of insects with imcomplete metamorphosis and larvae are the immatures of insects with complete metamorphisis. A single species of insect does not have both larval and nymphal stages as do single species of mites.

If the mites are numerous in mulch alongside buildings, removing the mulch should reduce the numbers that come indoors. Cracks and crevices, such as along baseboards, can be sprayed with a pyrethroid, such as aerosol flying and crawling insect spray, by the homeowner. If ignored, the mites will likely die within two to three weeks indoors. The drier air indoors, lack of mites to feed upon, and short life cycle of the mites at this time of year will combine to eliminate them. (Phil Nixon)

Phil Nixon

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