Recent weather systems have brought rain to many areas of Kansas during the past two weeks. This is a welcome relief from drought conditions that have dominated most of the winter and spring. The wheat crop is at the flag emergence and boot stage of development in the southeast and south central regions of the state. Wheat in the central and western regions of Kansas is moving through the jointing stages of growth.
The dry conditions appear to be suppressing disease in much of the southern Great Plains with Texas and Oklahoma reporting lower-than-normal stripe rust and leaf rust activity. That began to change this week when Dr. Bob Hunger, wheat pathologist from Oklahoma State University, reported active stripe rust and leaf rust in parts of southern and central Oklahoma. This is potentially important because it sets the stage for disease to spread into Kansas and other key wheat producing states to the north.
Scouting reports from Kansas indicate that the disease levels remain low in most areas. The weather has been favorable for stripe rust in the southeast portion of the state and the disease reported in Montgomery County has moved into upper leaves in some fields (Figures 1 and 2). There are currently no reports of stripe rust or other disease problems developing in other parts of Kansas.
Figure 1. Duration of weather conditions favorable for the development of stripe rust in wheat for past 14 days. Some areas in southeast Kansas have experienced favorable conditions. Data from the Kansas Mesonet (http://mesonet.ksu.edu).
Figure 2. Observations of disease status in the Kansas wheat crop. Map created by Erick DeWolf, K-State Research and Extension.
Josh Coltrain, K-State Extension Agent in the Wildcat Extension District, reports that many growers are considering a fungicide to suppress stripe rust in the southeast region. Most fungicides can be applied to wheat through the heading stages of growth (Feekes 10.5). Once wheat begins to flower, the production options are reduced because of label restrictions. More information about fungicide options can be found online at the KSRE bookstore at: https://www.bookstore.ksre.k-state.edu/pubs/EP130.pdf
Erick DeWolf, Extension Plant Pathologist
dewolf1@ksu.edu
Chip Redmond, Kansas Mesonet Manager
christopherredmond@ksu.edu
Mary Knapp, Weather Data Library
mknapp@ksu.edu
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