Winter Grain Mite (Penthaleus major)


Mites are tiny arthropods that feed on the sap of host plants. Because they are so small, use a hand lense to see them. They have 8 legs (6 in the first stage). The brown wheat mite is about 0.025 inch long (0.635 mm), oval shaped and dark red or brown in color. The winter grain mite is larger, 0.04 inch long (1 mm) and dark bluish black with red-orange legs and a reddish patch on the upper side. Banks grass mite is extremely small, 0.001 inch (0.025 mm), and yellow to cream colored. It is the only prominent wheat mite that webs the leaves.


Leaves injured by brown wheat mite first appear silvery and later take on a scorched appearance. Injury caused by the winter grain mite results in yellowish leaves and stunted plants. The damage caused by this mite is similar to winter-kill.