A red mite on a dime show how tiny the critter is. Photo courtesy Joe Boggs/Ohio State University Extension
Are you seeing red?
Tiny red dots that move on concrete, rocks and other hard surfaces? And I mean tiny.
These are red mites, not a bug, but an arachnid, which makes them related to spiders. These are a seasonal, minor pest, frequently called concrete or sidewalk mites because they seem to prefer hard surfaces to plants, people and pets.
Steve Mayer, horticulture education at Purdue Extension Marion County, said he’s seen “lots of them. More than I have ever seen, mainly on non-plant surfaces. Red mites seem to be everywhere, but not on plants,” Mayer said.
“I first became aware of them when we found them inside our office on our postage meter. They leave a red mark when crushed,” he said. “When mites leave a red stain we usually think of clover mites but these mites do not look like them. Clover mites are not a vivid red color and their two front legs are twice as long as the other legs.”
Joe Boggs, an extension entomologist at Ohio State University, said he continues to get reports of “huge numbers of tiny, fast-moving, bright red mites scurrying around on sunny surfaces, such as picnic tables, patios, sidewalks, concrete retaining wall and on the outside of homes and buildings.”
Three red mites on piece of wood. Photo courtesy Steve Mayer/Purdue Extension Marion County
Red mites prey on other mites and small insects and supplement their diet with pollen. Early in the season, these mites are pollen feeders, then become predaceous as more prey develops, according to 2012 research at Wittenberg University in Springfield, Ohio.
Like Mayer, Boggs recognized the mites’ nuisance characteristics by small red stains. This time, the red dots were on Boggs’ wife’s white pants after sitting outdoors. There have been a few reports that a bite from one could cause dermatitis, although bites seem uncommon.
It’s unclear why concrete mites appear in large numbers in sunny locations in spring. But the gatherings are short lived and subside quickly. Because of their habit of leaving red marks, they could threaten to spoil outdoor activities and white clothing. Some Indianapolis-area landscape services and pest control companies have had customer requests to spray pesticides.