This week brought some mixed reports on the wheat disease situation in Kansas. We continue find stripe rust and leaf rust at low levels in many fields. The distribution of these diseases in the state changed slightly this week, with a few more counties in the central region of the state reporting low levels of both stripe rust and leaf rust in the middle canopy (Figures 1 and 2). Rust moved to the upper leaves in few counties in this region.
Stripe rust is developing more slowly than expected, but expanding distribution and a few reports of higher incidence still suggests we are at a moderate risk of problems with stripe rust.
The additional reports of leaf rust are also noteworthy. Leaf rust can also cause more than 20% yield loss when it becomes established on the upper leaves prior to flowering.
Growers with wheat that is between boot and flowering should be scouting their wheat for signs of stripe rust, leaf rust, or other diseases. Fields with good yield potential and seed production fields, where the value of the grain is higher, would be priorities for fungicide application. Growers with fields that were damaged by freezing temperatures and heavy snowfall should carefully evaluate yield potential before applying fungicides.
Figure 1. Current distribution of stripe rust in Kansas.
Figure 2. Current distribution of leaf rust in Kansas.
Erick DeWolf, Extension Wheat Plant Pathologist
Romulo Lollato, Wheat and Forages Specialist