Dr. Robyn Roberts
Field Crops Pathologist and CSU Assistant Professor Robyn.Roberts@colostate.edu*
970-491-8239; @RobynRobertsPhD (Twitter)
*Email is the best way to reach me
Reports of mosaic virus symptoms have increased this past week, with moderate levels reported in symptomatic fields. All of the samples we have tested so far this year have been positive for both Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) (Figure 1). In WSMV-resistant varieties, WSMV levels have been low, so the symptoms observed in these varieties are very likely caused primarily by TriMV. However, in susceptible varieties, both WSMV and TriMV levels have been very high. This suggests that the WSMV resistance is still working in WSMV-resistant PlainsGold® varieties, but we will continue to monitor for resistance-breaking. The drought has contributed to the severe virus disease symptoms this year.