Wheat Virus Survey Results

Since wheat harvest is now finished and we are headed into corn season, I thought I would share the general results of the wheat virus survey.  In this survey we test for five known wheat-infecting viruses, Cereal Yellow Dwarf Virus (CYDV, formerly known as BYDV-rpv), Barley Yellow Dwarf Virus (BYDV-pav), High Plains Virus (HPV), Wheat Streak Mosaic Virus (WSMV), and Triticum Mosaic Virus (TriMV). A total of 368 ELISA's (enzyme-linked immunosorbent assay) were performed in the diagnostic clinic. Of all the ELISA's run, 252 of these were for the wheat breeding program.  There were a total of 116 wheat samples sent in to the clinic from growers, extension agents and crop consultants.  The results of those 116 samples were 79 virus positive and 37 virus negative.  The results reported here are the compilation of the 79 virus positive wheat samples from growers and do not include the results of the wheat breeding program.

• 39 samples had single virus infections; the sample was positive for only one of the five viruses tested.
• CYDV (3 positives)
• BYDV-pav (13 positives)
• HPV (6 positives)
• WSMV (14 positives)
• TriMV (3 positives)
• 40 samples had co-infections; meaning the sample was positive for two or more of the viruses tested.
• 32 samples were co-infected with 2 viruses
• 7 samples were co-infected with 3 viruses
• one sample was co-infected with 4 viruses
• there were no samples that tested positive for all five viruses
• Of the 32 samples that were positive for two viruses, 17 of those samples were positive for WSMV and TriMV.

Overall, WSMV is still the number one wheat virus in our state, either singly or co-infected with other viruses.

Stripe Rust is in Colorado!

Posted by Ned Tisserat and Scott Haley on the Cereal Rust Survey listserv:  Multiple observations of stripe rust on wheat have now been made in Eastern Colorado.  We just received three samples in the Diagnostic Clinic yesterday that confirms these observations.  Infections thus far are most prevalent in the southeast part of the state but it appears to be moving north as would be expected.  Infections at this point appear to be at low levels, but good moisture and continued moderate temperatures may promote its continued development.  Wheat in SE Colorado is mostly a few days either way of the heading growth stage.  If you are out scouting fields and find rust, we would like to have samples sent to the Diagnostic Clinic so we can forward them to WSU for race typing.