Likely clover mite

Often found on vegetation and lawns; may gather on sunny exterior walls, windowsills, and decks.

Pierces plant cells and feeds on their contents, especially on grasses and clover.

Tiny, reddish-brown mites that may appear in large numbers in spring or fall and can enter buildings through small gaps. Crushing them can leave red stains.

Harmless to people, pets, and buildings; large numbers can be a nuisance and may cause minor plant stippling.