This past week I was at field days in southwestern Oklahoma (Apache and Altus), and northeastern Oklahoma (Afton). I didn’t see a single leaf or stripe rust pustule at any location. Wheat in southwestern OK ranged from at flowering to kernel formation, and typically was short (less than knee high). There were a few exceptions to this, namely a couple fields near Apache that had been planted on summer fallow ground. Wheat in these two fields looked good with some powdery mildew on the low to mid-canopy. There also was evidence of root rot (white heads) that was caused by Fusarium (Figure 1). This root rot was at a low incidence. By contrast, wheat in northeastern OK was at flowering and typically was over knee-high, thick, and with high yield potential. On many varieties, powdery mildew was heavy in the low and mid-canopy, and in a few instances also was present on the flag leaf (Figure 2). Besides powdery mildew, Septoria leaf blotch was heavy throughout the lower leaves of most varieties. In northeastern OK it appears that if a fungicide is going to be sprayed, that needs to be applied as soon as possible.
--Bob Hunger, Extension Plant Pathologist, Oklahoma State University
For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu
For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org