There could be a looming threat of stem rust to wheat farmers in Kansas, according to Erick DeWolf who is the Kansas State University Extension plant pathologist and professor of plant pathology. Stem rust is a disease that historically caused major yield losses in the Great Plains, but has been genetically controlled for decades.
The last major outbreak was in the 1980's, but this base of genetic resistance has eroded in recent years, he said. Currently, western Kansas has more than 30 percent of its acres planted to stem rust susceptible varieties, and the more acres planted, the more vulnerable the crops are to an outbreak. The spotlight is on western Kansas because of the large number of acres planted to susceptible varieties, but DeWolf is also concerned about central Kansas. The problem is increasing in Colorado, Oklahoma, and Texas, and other parts of the world.
This disease of wheat often survives the winters in parts of Texas and Mexico, and then storm systems move them north. DeWolf says to avoid planting the highly susceptible varieties, and if already planted, a fungicide treatment could help reduce the yield losses, but the timing of fungicide application is later than for many other diseases of wheat. For more information, refer to the K-State's Wheat Variety Disease and Insect Ratings Guide and go online to the Kansas Wheat Alliance website at kswheatalliance.org.