Pest e-alerts, 04/30/2012, v.11 no.23

              Entomology and Plant Pathology, Oklahoma State University
127 Noble Research Center, Stillwater, OK74078
405.744.5527
Vol. 11, No. 23
http://entoplp.okstate.edu/Pddl/
Apr 30, 2012
Wheat Disease Update
Bob Hunger, Extension Wheat Pathologist
On 24-Apr I traveled to the Custer City area (north of Clinton OK) and then to Apache (25 miles north of Lawton). On this route I stopped at several variety trials. Wheat was mostly in the full berry to milk stages (Marshall, Kingfisher, Custer City, Thomas, Apache) and over all looked good. Lodging has occurred in some trials, but did not appear to be widespread in many fields. Wheat in the Custer City area needs another rain to help complete the crop this year. Most of the wheat I looked at had anywhere from 12-20 meshes with two full berries and a third on the way.
On 26-27-Apr I traveled to southwestern OK and rated trials near Granite OK and attended the field day 7 miles west of Altus. During the drive to Granite, fields with a whitish/tannish cast begin to be noticeable in the Clinton area. This became more widespread as I approached Granite, and was even more pronounced west of Altus. This was the result of wheat maturing and of lack of rain rather than disease. Often the lower spots in fields or terraces were still fairly green with terrace tops and slopes having more of the whitish/tannish cast. As I examined fields, I could find no evidence of root rot or freeze damage, and nearly all of this wheat also had two full berries/mesh with a third on coming on. Both Dr. Jeff Edwards (OSU Small Grains Extension Specialist) and I received contacts at the end of the week from the Kingfisher to Watonga area asking about whiteheads in fields. Some of these descriptions sounded like root rot damage (see Dr. Gene Milus’ description from Arkansas), but we will not be able to confirm or refute this until next week. I am confident however, that the fields I saw in southwestern were turning color due to maturity and dryness rather than from root rot (Fig 1). In fact, at the trial west of Altus I could almost get my foot into some of the cracks in the soil. A rainfall is needed.
Regarding foliar diseases, most of the wheat in southwest OK does not have much foliage left. Where there was foliage, leaf rust was the most prevalent disease, but I could also find some stripe rust. This is also true around Apache and Stillwater where more rain has fallen and