Recently, I have been seeing some Septoria/Leaf and Glume Blotch developing in some area wheat fields. Not every wheat field will have this disease so it is important for growers to scout their fields thoroughly. Many wheat fields may be too far along for a fungicide treatment but there may still be a few fields scattered around where a fungicide application could be made if needed.
Here is an excerpt from the 2014-2015 UGA Wheat Production Guide regarding this disease:
Lesions (spots) are initially water-soaked and then become dry, yellow, and finally brown. Lesions are generally oblong, sometimes containing small black spore producing structures called pycnidia. The lesions are often surrounded by a yellow halo. Lower leaves are generally more heavily infected, with lesions joining together to cause entire leaves to turn brown and die. If pycnidia are present on lower leaves when the uppermost leaf and the head begin to emerge, infective spores will move to the top of the plant in splashing rain even after a brief shower. Symptoms may not appear for 10-15 days on the top leaves or glumes on the head. By the time lesions are seen on the head, it is too late for effective fungicide use. Therefore, it is important to examine the lower leaves for lesions when making decisions about fungicide application, not just the top leaves. Lesions are first tan or brown on the upper portion of the glume while the lower part remains green. As the head matures, it becomes purplish to black in appearance from glume blotch. Leaf and glume blotch can reduce yield as much as 20% and reduce test weight due to grain shriveling even when disease severity is low.
Here are some pictures I took today of some Septoria/Glume Blotch in an area wheat field:
Here it is infecting the awns of the head:
If you have any questions, contact your local county agent for more information.