February and March are critical months for the wheat crop and strongly influence the outlook for the 2016 production season. Mild temperatures and adequate moisture during these months will increase yield potential of the crop, but also increase the risk of severe disease.
The reports to date indicate that stripe rust is active at low levels in Texas (Clark Neely, Texas A&M). Bob Hunger, Extension Plant Pathologist for Oklahoma State University, has reported low levels of stripe rust in southern Oklahoma, and that leaf rust was detected at low levels near Stillwater. These reports are important because severe outbreaks of stripe rust and leaf rust in Kansas are often proceeded by outbreaks of disease in these areas. Weather conditions in Texas and Oklahoma over the next 6 weeks will have a major effect on the development of disease in those states. If the disease continues to develop in the south, the risk of Kansas experiencing severe increases dramatically.
In checking research plots near Manhattan this week, I found trace levels of leaf rust. This is not unusual for this time of year and it is still too early to know if leaf rust will survive the winter this far north. In many years, leaf rust is detected in February; however, dry conditions limit the spread of the disease to new growth fail in March and the disease dies out locally. Low levels of powdery mildew were also observed at this location.
There is no need for management activities at this point. However, growers should be listening for more reports of disease in Texas and Oklahoma. Scouting for overwintering leaf rust in Kansas can begin anytime, but is most useful in late March and early April.
Erick De Wolf, Plant Pathology