This article was written by Dr. Bob Hunger, Extension Wheat Pathologist
Department of Entomology & Plant Pathology
Oklahoma State University – 127 Noble Research Center
Wednesday through Friday (May 23-25) of last week, I was in western Oklahoma (Clinton area) and at field days in the panhandle at Goodwell and Hooker (Texas County), Keyes (Cimarron County) and Balko (Beaver County). The only disease observed of significance was indicated by white heads in fields. Often this was the result of Fusarium (dryland) root rot as reported in the last update (May 17, 2018). In fields showing this root rot, the white heads and white tillers were scattered across the field with an incidence ranging from low to moderate (Figure 1). Other fields in the panhandle exhibited large areas of not just white heads and tillers, but also white secondary tillers that had not headed. In these fields, some root rot was found, but Dr. David Marburger (OSU Small Grains Extension Specialist) and I believe that many of the white tillers/secondary tillers were the result of drought, freeze, or a combination of both. Often such tillers showed clean lower stems with no indication of root rot. We believe these secondary tillers were completely white without heading because they were sloughed off as a result of the stress from drought, freeze, or a combination of both. We suspect that more of these whiteheads will show in the coming week in northwestern OK and the panhandle, but the wheat crop is quickly turning and the whiteheads may not be as evident.
This likely is the last update I will be sending out this season as harvest in the southern half of Oklahoma has started with the crop quickly maturing in the northern half.
Figure 1. White heads of wheat due to root rot. Typically the white heads are scattered in a field and can range from a low to high incidence. Notice in the middle photo just a few tillers of an individual plant are affected. [Credit for middle photo to Brad Babek, County Educator, Washita County]