Many causes for the problem
It's been said that once you get the wheat crop seeded, 90 percent of the work is done. That doesn't keep farmers from worrying about stand establishment over the next several weeks - particularly as drought conditions continue to plague the young wheat crop.
Jim Shroyer, Extension agronomist at Kansas State University, says that ideally, over the next few months wheat will take on a solid green color, form a secondary root system, and develop one or two tillers in addition to the main tiller. But sometimes there are problems, including discoloration, stunting, leaf loss or dying of emerged seedlings.
Causes of yellowing or stunting of the crop this fall could include:
* Nitrogen deficiency
* Poor root growth.
* Aluminum toxicity
* Leaf rust
* Cold temperatures
* Greenbugs or bird cherry oat aphids
* Hessian fly
* Flea beetles
or a complete discussion, see K-State's publication S-84, "Diagnosing Wheat Production Problems" at: http://www.ksre.ksu.edu/library/crpsl2/s84.pdf/