Rust and powdery mildew threaten Central and Southern U.S. Great Plains wheat

Syngenta and the Cereals Disease Laboratory are reporting rust and powdery mildew development on winter wheat in the Central and Southern Great Plains from Texas to Nebraska. Syngenta recommends an aggressive scouting program along with weather monitoring and timely fungicide application.

This spring’s mild temperatures, moisture and devastating tornadoes have created the perfect conditions for travelling rust spores. Every year, stripe rust and leaf rust pathogens ride wind currents from the southern states to the Dakotas, infecting crops and, according to the Cereals Disease Laboratory, resulting in yield losses of more than 20 million bushels.

Tony Driver, a Syngenta agronomic service representative based in Texas, reported that the moisture and mild temperatures this year have been good for the productivity of the wheat crop. “Overall we’re seeing a good-looking crop; we’re about two to three weeks ahead of the normal schedule,” he explained.

The warmer weather and increased moisture is maximizing plant growth; however, it also makes conditions extremely conducive to fungal disease. “We’ve seen an increase in powdery mildew, stripe rust and leaf rust. In addition, we’re also seeing earlier pressure from armyworms, so it will be important to monitor for both disease and insects,” he continued.

Syngenta recommends that growers in Oklahoma, Kansas and Nebraska begin scouting fields and prepare for fungicide applications.

Management Recommendations

Experts predict that this spring’s moderate weather conditions will cause a rise in disease prevalence in the Central and Southern Great Plains. Greg McCormack, a Syngenta cereals crop specialist based in Kansas, recommended that growers closely monitor crops for flag leaf emergence and prepare for fungicide application. McCormack said, "Not only do we have more yield potential to protect than the past couple of years, but there is also potential for more disease pressure.”

Timing is the most important factor in disease management this season. Wheat growers will need to make fungicide decisions before disease is readily apparent in the field. In the past, when growers have seen good yield potential and prime conditions for disease development, preventative fungicide application has been a profitable strategy.

Flag leaf emergence is the critical point; protecting the flag leaf helps maximize yield potential because it is the leaf responsible for feeding the grain and contributing most to the final grain yield.

"Quilt® and Quilt Xcel® fungicides offer growers two modes of action with preventive and curative activity. The increased levels of azoxystrobin and systemic-xylem mobility of Quilt Xcel provide better protection,” McCormack explained. “We’ve also seen enhanced Plant Performance™ activity that helps wheat growers achieve maximum grain fill and profit.”

As the Cereal Disease Laboratory continues to track rusts, powdery mildew and other diseases through the Central and Southern Great Plains, winter wheat growers should ensure their crops are protected from diseases to maximize yield. Thorough scouting, weather monitoring and preventive and curative fungicide programs will aid growers in implementing a successful disease-management plan throughout the growing season.