Wheat streak mosaic (WSMV) (Tritimovirus Wheat Streak Mosaic Virus) is a viral pathogen. It was first detected in Texas in 1984.
Wheat streak mosaic has the potential to be a very serious disease of both winter and spring wheats. Losses may range from slight to complete crop failure. Distribution may be restricted to a few fields, or the disease may be widespread. WSMV can be spread mechanically through leaf rubbing, but it is primarily spread by the wheat curl mite, Aceria tulipae, a very tiny mite.