Fusarium head blight
Southeast Kansas has received frequent rains during the recent weeks. The extended periods of high relative humidity brought on by these rain showers are increasing the risk of Fusarium head blight (FHB) in this region. The wheat in this part of the state has been heading this week and will soon be flowering. These growth stages are important because the fungus that causes Fusarium head blight is most likely to infect wheat during flowering.
Growers in this area should be monitoring weather conditions carefully and might consider fungicide applications at flowering if weather conditions remain favorable. Prosaro, Proline, and Caramba are the best options for suppression of FHB. Folicur (or generic tebuconazole) would also be reasonable option, but the level of suppression is slightly lower than that of the Prosaro, Proline, or Caramba. Fungicide products containing strobilurin active ingredients (Headline, TwinLine, Quilt, Stratego) are not good options for FHB control because they can aggravate the mycotoxin problem cause by this disease.
There are some Web-based tools available to help growers evaluate the risk of FHB. These tools provide daily estimates of disease risk for FHB. State-specific commentary about the risk of disease is presented along with the risk maps. To access the information online go here and select the risk tool. You can also go directly to the risk tool.
The state-specific FHB commentary can also be sent directly sent to you by email or text message on your phone via the FHB-Alerts system. To sign-up for this free service go to: http://scabusa.org/fhb_alert.php
Leaf rust and stripe rust update
Recent rainy weather earlier this week may be stimulating some additional wheat diseases in parts of central and eastern Kansas. Low levels of leaf rust were found in Sumner County earlier this week. The disease was found on the top two leaves (Flag and F-1) on susceptible wheat varieties. Low levels of stripe rust were also found at this location. The stripe rust was still in the mid-canopy, but was actively producing spores after some cold wet weather this week. Severe powdery mildew was also noted just south of Wichita. This was somewhat surprising given the dry conditions during the past month, but these finds suggest that there is enough disease is some fields with a yield potential may still justify spraying fungicides.
More information about fungicide decisions in wheat was provided in last week’s e-Update.