Grass mites are not insects, but tiny members of the class Arachnida, making them relatives of spiders, ticks, and scorpions. The term “grass mite” is a general description that covers several species, including clover mites, Banks grass mites, and winter grain mites, which all feed on turfgrass. Since these pests are so small, identifying them in a lawn requires understanding their minute physical characteristics and the specific signs of damage they leave behind.
General Appearance and Scale
The appearance common to all turf-damaging mites is their extremely small size, with most adults measuring less than one millimeter in length. They are often smaller than the head of a pin, making them nearly impossible to see clearly without magnification, such as a 10x hand lens. Like other arachnids, adult mites have eight legs and an oval or rounded body shape, which appears to be a single fused segment.
Their color varies depending on the species and whether they have recently fed, but they are generally pale, yellowish, or greenish before consuming plant material. When viewing them in the turf, they often look like dark, moving specks. Larvae are even smaller and possess only six legs, gaining the final pair after the first molt.
Key Differences Between Common Turf Mites
While all grass mites are tiny, three common species have distinct features that help differentiate them.
Clover Mite
The clover mite, a cool-season species, is typically reddish-brown to brick red. It is easily identified by its extremely long pair of front legs, which are often held forward, giving the illusion of antennae. When crushed, this species leaves a distinct reddish stain.
Banks Grass Mite
The Banks grass mite is a warm-season species that thrives in hot, dry conditions. This mite is usually a yellowish-green color and lacks the long forelegs seen on the clover mite. It may also produce fine, light webbing on the grass blades during heavy infestations.
Winter Grain Mite
The winter grain mite is distinct because of its dark blue to black body and highly conspicuous reddish-orange legs. This cold-weather pest is active when temperatures are between 40 and 70 degrees Fahrenheit. It is known for having a small reddish spot on its back.
Identifying an Infestation
Since mites are difficult to spot, their feeding damage is often the first noticeable sign of an infestation. Mites feed by puncturing plant cells and sucking out the contents, leaving behind tiny, bleached-out spots called stippling. This damage causes the grass to appear discolored, often taking on a yellowed, bronzed, or grayish-silvery cast that is frequently mistaken for drought stress.
Infestations are often localized, especially in warm areas near sidewalks, driveways, or building foundations. To confirm their presence, shake suspicious grass blades over a piece of white paper or a clipboard. The dislodged mites will appear as tiny, slow-moving specks against the white background. Smearing these specks across the paper will produce a reddish streak, confirming the presence of mites.