On Friday, March 28th I made a tour through northwestern Oklahoma to diagnose a few problem fields and get a better feel for the wheat crop condition. I have provided a brief description of what I saw below. I did not make it to southwestern Oklahoma this trip, but by all accounts the wheat is dry, brown, and barely hanging on. A best case scenario in areas southwest of Apache this year is a poor wheat crop. It will have to rain a lot between now and harvest for this to happen.
Reports from Apache eastward are somewhat better. The wheat crop in this area still has potential, but the potential is declining. A farmer from the Hinton area called yesterday and indicated that moisture could still be found about 1 inch below the soil surface, but the top is still very dry. We need a soaking rain to move nitrogen into the rooting zone and to perk the crop up post dormancy.
My first stop this morning was at Lamont. Wheat in this area is smaller than normal and is at approximately Feekes GS5. There were several yellow areas in fields and uneven wheat. Much of this yellowing appeared to be nitrogen deficiency, but not all of it was due to insufficient top dress nitrogen. We simply have not had enough moisture to get good movement of top dress N into the rooting profile and for the wheat crop to take up applied N. Some of the yellowing was also due to drought stress. Some of the yellowing could have been due to brown wheat mite and/or winter grain mite activity (described more below).
My second stop was at our Cherokee variety plots. Wheat in this area was uneven, similar to Lamont. As shown in the picture below, part of our plot area was showing significant yellowing. Initially, I thought this was due to changes in soil type/nutrient variability. Upon closer inspection, this area was infested with brown wheat mite. These symptoms have only started to show in the last week or so. Thanks to variety trial cooperator Kenneth Failes, this situation will be remedied as soon as the wind settles.
Next stop was Alva, where the trend of uneven and yellow wheat continued. As shown in the picture below, there were several fields in the area with spots of dead or nearly dead wheat. Brown wheat mites were found in most of these fields and probably weakened plants which increased the amount of winterkill. In some fields seed had been placed at the proper depth, but the seed trenches were partially filled with residue rather than soil. Residue provides less insulation than soil and likely made heavy residue areas more prone to winterkill. I also noticed in these fields that the crown of the plant had developed in residue rather than soil, which likely increased winterkill. I looked at additional no-till fields in the area with severe winter injury, but plants that were still viable. Grazed fields seemed to have greater injury than non-grazed.
I looked at a few fields south of Enid. Unlike the fields in Grant, Alfalfa, and Woods Counties, this primary issue in these fields was winter grain mite instead of brown wheat mite. The symptoms were areas of the field having a silver tint. Some areas had died or lost several tillers and these areas got bigger as the season progressed and dry conditions worsened.
I ended my tour at Marshall, Oklahoma where I did not find any insects, but did find some thirsty wheat. All of the insect issues I encountered today can be corrected with scouting and insecticides. Wheat winterkill was present, but rarely affected entire fields and was not that widespread. The primary concern for all of Oklahoma remains lack of moisture. There are some fields in north central and northwestern Oklahoma with good yield potential; however, the best areas are starting to turn blue due to lack of moisture. Another couple of weeks of warm temperatures and wind without rain will turn blue wheat to brown. We need moisture.