With Recent Rains- Dr. Bob Hunger Reports Foliar Diseases on the Rise in 2016 Oklahoma Wheat CropSat, 23 Apr 2016 11:06:18 CDT
Oklahoma State University's Dr. Bob Hunger, Extension Wheat Pathologist in the Department of Entomology & Plant Pathology has released his latest wheat disease findings- released via email on Saturday, April 23rd.
Dr. Hunger starts with a Correction: " In my last update, I indicated Prosaro (Bayer CropScience) as the only fungicide labeled for application at a growth stage (GS) later than full head emergence (GS 10.5). Caramba (BASF) also is labeled for application through GS 10.5.1, which is the beginning of anther emergence (flowering). Sorry for the omission.
"Rain over the last week was extremely beneficial to wheat across Oklahoma, with the cool, cloudy and wet weather also serving to slow down wheat progression. Wheat around Stillwater is basically at flowering. Gary Strickland (Extn Educator; Jackson County in SW OK) indicated wheat in his area experienced some hail damage, and Greg Highfill (Extn Educator; Woods County in NW OK) indicated that although not widespread, he has seen a bit more freeze damage than expected. Overall though, my impression is that freeze damage is minimal.
"Cool temperature and rain also will facilitate foliar disease development. Especially over the last several days, there has been extended periods of dew on wheat, which provides an optimum environment for increasing foliar diseases. As temperature now rises, leaf rust should become more common. In fact, reports from Texas (see below – “Reports from Other States”) indicate increasing leaf rust in Texas. Brian Olson (Senior Agriculturalist OSU) spent yesterday rating breeder lines here at Stillwater. He reported seeing some active stripe rust, but increasingly more powdery mildew, leaf rust, and barley yellow dwarf. Dr. Brett Carver (OSU Wheat Breeder) reported much the same at the Pasture Research Center near Marshall, OK (about 30 miles west of Stillwater). However, stripe rust is still active."
Reports/excerpts of reports from other states:
Texas: Taken from the USDA Cereal Rust Bulletin (Report No. 2; April 20, 2016): “Wheat leaf rust increased rapidly in plots at Castroville in south Texas and Baton Rouge in southeastern Louisiana. Dry conditions from Oklahoma into Nebraska likely limited leaf rust development there, but recent rains will be conducive for new development.”
Texas: Dr. Clark Neely (Small Grains & Oilseed Extn Specialist) Texas A&M AgriLife Extension, College Station; April 15, 2016): “With regards to wheat stripe rust, leading up to this past week I was observing numerous teliospores around central and south Texas indicating that the stripe rust was shutting down; however, Texas received a significant round of rainfall this week with much of the state predicted to receive between 2 and 7 inches over the next 7 days. I would anticipate some reactivation of the stripe rust in areas where it was declining and continued infection in northern/western regions that are just now seeing it. There was a recent report from Dawson County, TX (western TX) which cited heavy stripe rust pressure. Until now stripe rust pressure has been limited in this part of the state.”
Kansas: Drs. Erick DeWolf/Romulo Lollato (Extn Wheat Pathologist/Wheat & Forage Specialist), Kansas State University, Apr 22, 2016: “Reports of wheat stripe rust continued to roll in this week. The disease was already established in many parts of south central and southeast Kansas. Stripe rust has moved to the upper in some fields within these regions now. This movement to the upper canopy is important because these leaves contribute the majority of the energy used to make grain. The other key update comes from western Kansas where the disease was reported at low levels this week. The first reports came from irrigated fields but a few dryland fields were subsequently found to have stripe rust also.”
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