Stripe Rust Damages Some Southeast Missouri Wheat

Published: March 23, 2012

Stripe rust can be a yield-robbing disease of susceptible wheat when the weather is suitable for infection. It was detected in a few southeast Missouri wheat fields in early March and was detected in several southeast Missouri fields by mid March. As of mid March, it has not been reported north of a line from New Madrid to Poplar Bluff. This disease presumably spread to Missouri from the many infected east Arkansas wheat fields during late February and early March. Spread of this disease to other Missouri wheat fields can't be predicted. However, weather predicted for the last few weeks of March will be suitable for this disease to spread.

All wheat fields should be scouted for this disease. The conditions that justify an application of fungicide to wheat for protection against this disease have not been developed for Missouri because this disease rarely develops here.

Symptoms of stripe rust vary because of variety infected. Generally, the pustules are yellow, appear principally on leaves, and are often arranged in stripes on the leaves, see http://agfax.com/2012/03/22/arkansas-wheat-managing-this-years-stripe-rust/.

Farmers that expect high wheat yields, greater than 60 to 70 bu/acre, should inspect each field and consider apply a fungicide to protect wheat against this disease if infection is found in a field. Do not assume all fields are infected. Any of the registered wheat fungicides will work, but propiconazole (Tilt and generics) and tebuconazole (Folicur and generics) are the least expensive and best for stopping infections that have already occurred and stopping new infections. Strobilurin fungicides such as azoxystrobin (Quadris) and pyraclostrobin (Headline) are best for preventing new infections but weak for stopping existing infections. Combination products such as Quilt, Stratego, Absolute, and Twinline are good for stopping both new and existing infections. Prosaro (prothioconazole + tebuconazole) and Caramba (metconazole) are primarily used at flowering time to suppress Fusarium head blight (scab). A second fungicide application may be needed at late-boot stage of growth for other diseases, so don't spend a lot on this early application.