Reports of wheat with severe infections of wheat streak mosaic, triticum mosaic, and High Plains mosaic continue to flow in this week. Based on these reports and our own scouting, we are beginning to get a better picture of the distribution and intensity of the disease problem. Our preliminary evaluation is that the western half of the state is experiencing high levels of the disease with many counties reporting above-normal levels of wheat streak mosaic (Figure 1).
A large part of the west central region of the state is experiencing extreme problems with the disease. Our survey efforts to date indicate that nearly all the wheat fields in this area are being affected by wheat streak mosaic to some degree. Many fields are severely diseased and will likely experience more than 70% yield loss or could be a complete loss.
These disease problems were set in motion last summer when summer weather conditions favored multiple flushes of volunteer wheat that harbors the virus and curl mites that spread the disease. Mild fall temperatures allowed additional time for the disease to spread to the newly emerging wheat crop. Unfortunately, there is nothing that can be done to treat the infected plants and stop the spread of the disease. We will continue to gather more information developing epidemic and follow up with additional information soon.
Figure 1. Preliminary estimates on the distribution and intensity of wheat streak mosaic in Kansas.
Erick DeWolf, Extension Wheat Plant Pathologist
Romulo Lollato, Wheat and Forages Specialist