Early alert for wheat diseases in SD this spring

By Scout Nelson

South Dakota winter wheat fields are experiencing conditions favorable for disease outbreaks, particularly Septoria. Farmers are advised to closely monitor each field, identifying any present diseases and assessing the level of infection to determine if early fungicide application is necessary.

Septoria is prominent this season, caused by the fungus Zymoseptoria tritici. It grows in cool, moist conditions, creating elliptical, tan-brown lesions with yellow halos on wheat leaves. As these lesions progress, their centers die off, and speckled gray-brown pycnidia become visible, making the lesions easily identifiable.

Tan Spot, another significant threat, results from the fungal pathogen Pyrenophora tritici repentis, which lingers on old wheat stubble. It starts on lower leaves and can spread, potentially reducing yield by impairing tillering and causing premature leaf death through coalescing lesions marked by dark brown centers and yellow halos.

To aid in managing these risks, South Dakota State University offers a Small Grains Disease Prediction Tool. This tool helps track weather conditions conducive to leaf spot diseases and Fusarium head blight (FHB). By selecting your specific growth stage and nearest weather station, you can receive tailored forecasts to help decide whether to apply fungicides. The tool also provides specific guidance for managing FHB as wheat reaches the heading stage.

Farmers should utilize this prediction tool to make informed decisions about fungicide applications, potentially preventing significant yield losses due to fungal diseases in their crops.

Photo Credit: gettyimages-ygrek