Southern corn rust recently started making its way into areas of southern Nebraska. While symptoms are minimal at this time, the disease could spread rapidly in a matter of days. The University of Nebraska–Lincoln’s Institute of Agriculture and Natural Resources also reports confirmed cases in western Missouri and southern Kansas. Because southern rust is a wind-borne fungus and has the potential to keep spreading, growers should get in their fields to start scouting for symptoms now.
Southern corn rust can be detected on the leaves of corn plants. The fungus leaves behind tan and/or orange discoloration on the leaves, which is actually the southern rust pustules clustered closely together on the leaf surface or leaf sheaths. According to the University of Nebraska–Lincoln’s report, the disease favors warm temperatures and moisture, so once the disease has been detected, you must continue to monitor your corn acres for spread of the disease and follow the weather reports. Watch for warm temperatures, high humidity and forecasted rain. These conditions could greatly exacerbate the situation. While southern rust can be devastating to yields, timely fungicide applications can help control the disease.
If symptoms have reached a level that warrants action, I recommend growers invest in a foliar fungicide that is applicable to the disease, such as fungicides that also help treat common rust and grey leaf spot. I also advise growers to watch their fields after residual control of that particular fungicide has worn off to ensure the disease does not come back.
If you are in area that has reports of southern corn rust or if you have confirmed the disease in your field, you should continue monitoring your fields now through harvest. Enlist the assistance of your local Stine representative to learn more about southern corn rust and how to prevent yield loss.