Poster: Biology & Disease Mgmt: Virology
Impact of downy brome (Bromus tectorum) and volunteer wheat on risk of winter wheat infection by Wheat streak mosaic virus
N. RANABHAT (1), Z. MILLER (1), E. LEHNHOFF (2), F. MENALLED (1), T. SEIPEL (1), M. BURROWS (1) (1) MONTANA STATE UNIVERSITY, U.S.A.; (2) New Mexico State University, U.S.A.
Wheat streak mosaic is caused by Wheat streak mosaic virus (WSMV) which is vectored by the wheat curl mite (WCM, Aceria tosichella Keifer). The mite and virus can survive on multiple grass species that act as reservoirs for WSMV. Understanding the effect of alternative hosts on risk of WCM infestation and WSMV infection in newly emerged winter wheat crops is crucial for disease management. We assessed WCM immigration onto trap plants and the influence of alternative hosts such as downy brome (Bromus tectorum L), and volunteer wheat on WCM infestation and WSMV infection of wheat. Wheat trap plants were monitored weekly in the fall over three years to assess the relationship among patterns of WCM infestation and WSMV infection with cumulative growing degrees days (GDD) of spring wheat, daily mean temperature with respect to alternative hosts. The relationship among GDD on WCM infestation and WSMV infection across alternative hosts was non-linear. Mite infestation and virus infection was positively correlated with daily mean temperature (P < 0.001) in the fall. The risk of WCM infestation and WSMV infection on trap plants from downy brome and volunteer wheat plots was higher during the late fall when compared to the bare ground control plots (P < 0.05). Overall, daily mean temperature is a better predictor of WSMV risk and the Wheat streak mosaic infection on emerging crop increases with the presence of downy brome and volunteer wheat species during the fall.