Wheat disease updates are written by Dr. Bob Hunger, OSU Extension Wheat Plant Pathologist
Just a few updates from this week. First, Mark Gregory (Southwest Area Extension Agronomist) reported the first stripe rust in Oklahoma for 2013 (see photo below). He found this stripe rust near Paul’s Valley on an Endurance/Duster mix, and “had to look hard to find it.”
David Nowlin (Caddo County Extn. Educator) sent in a wheat sample (Duster) exhibiting symptoms typical of wheat streak mosaic. If confirmed, this would be the second sample of WSM received from south central and southwestern OK.
Dr. Art Klatt (OSU Wheat Geneticist) has been this last week in Castroville, TX (far southern TX) rating breeder plots/lines for leaf and stripe rust. He has reported that, “In Castroville there is heavy leaf rust. We also found a little stripe rust but not enough to take readings and it was beginning to shut down due to temps. “ In Oklahoma, Dr. Klatt has reported seeing heavy powdery mildew in plots near Perkins, OK and at Stillwater, but has not yet seen any leaf or stripe rust.
Monday, 15-Apr, I and Nathalia Grachet (OSU Graduate Student) did plot work at the variety trial near Apache, OK. Wheat there was approaching Feekes 10. Flags leaves were out, but for most tillers, heads had not yet moved into the boot. Freeze damage was the most striking symptoms in this trial and surrounding fields, but tan spot/septoria/stagonospora, powdery mildew, and barley yellow dwarf symptoms also could be found – but, no leaf or stripe rust.
Today (17-Apr) I checked my trials and nurseries here at Stillwater. Wheat was at “pre” GS 10 with flag leaves fully out but the heads not yet fully moved into the boots. Even where the boot internode was fully expanded, the head was usually just beginning to move into the boot. I found powdery mildew low, but no rusts at Stillwater. Spots indicative of BYDV have appeared.