Winter grain mites are true, cool-season arthropods. These mites should become more active in the coming month.  Winter grain mites are most active when temperatures are generally at or slightly above freezing at night, but day temperatures are below 80 degrees F.  They are most commonly seen in the fall and spring periods when the weather is generally within these parameters. During moderate winters, the mites can remain active, even under the cover of snow. The mites hide in the thatch and at the bases of plants during sunny days, but come out at dusk to feed during the night. On cool, overcast days, the mites may surface during the daytime. The mites have tiny mouthparts which are used to rip holes in the leaf epidermis in order to suck out underlying cell contents. Empty cells turn white and heavily damaged grass blades can look blanched or as if they have an infection of powdery mildew. Turf damaged under snow cover can often look like snow mold damage - matted down, blanched foliage. Fortunately, winter grain mite damage is not too common in turf, and damaged turf rapidly recovers when the spring growth spurt begins.