Because of the widespread occurrence and severe epidemics of wheat streak mosaic and stripe rust in Nebraska in 2017 and 2015-2017, respectively, this wheat disease update is devoted to these two diseases.
Diseases continue to be absent or at very low levels in Nebraska wheat, with no reports of stripe rust or leaf rust and low levels of powdery mildew. Prevailing high temperatures and dry conditions in many areas have reduced the risk of significant disease development.
Wheat fields in southeast and south central Nebraska were green with little disease and high yield potential, based on this week's field survey. Recent rains relieved moisture stress in wheat in some areas of the state, but more rain is needed in southeast Nebraska to alleviate stress.
A survey of wheat in southeast Nebraska found diseases generally absent or at very low levels, mainly due to recent dry conditions. Continued scouting for foliar diseases is recommended, especially in areas that receive rainfall and where the wheat crop has not yet headed.
To differentiate sulfur deficiency from nitrogen deficiency in wheat, look for field patterns. Symptoms of yellowing limited to certain areas is more typical of sulfur deficiency. In addition, symptoms of sulfur deficiency are more conspicuous when soil temperatures are cold as in early spring.