An unidentified wheat virus has appeared in fields throughout western Kansas. The unknown pathogen causes the leaves to turn yellow and die.These symptoms are also associated with head death,wheat streak mosaic,and freezing; however,University of Kansas researchers have ruled out these possible causes. Researchers note evidence of the virus is in almost every field-although it has not yet destroyed the crop. University of Kansas virologists,with the help of researchers in Winnipeg,are trying to identify the proteins involved in the destruction of affected plants,so the genetic sequences may be compared to pathogens found in other parts of the world. One hypothesis-that nobody...