Issue No. 3, Article 11/April 20, 2012
Stripe Rust of Wheat Update
Stripe rust of wheat has been observed in several counties of southern Illinois. In some cases, stripe rust is present only on lower leaves, while in other cases stripe rust is present on the flag leaf. It is important that fields be scouted for stripe rust. Many of the fields in southern Illinois are now heading and beginning to flower (Feekes growth stage 10.5.1). Considering the growth stage of the wheat, fungicides registered for control of Fusarium head blight (scab), such as Caramba, Prosaro, and tebuconazole products (e.g. Folicur and others), would be the products to apply for protection against stripe rust if needed. In addition to suppressing Fusarium head blight, these products have excellent efficacy against stripe rust, and their labels allow applications during flowering (unlike other products that may not allow applications past Feekes 10.5 - heading).
For wheat growers in central and northern Illinois, it is also important to scout for stripe rust, as this disease will continue to move northward if favorable weather persists. In general, cool to moderate temperatures (< 70°F) favor stripe rust.
Stripe rust symptoms first occur as chlorotic linear streaks on the leaves. Later on, yellow to orange pustules will develop in a linear fashion ("stripes") within these chlorotic streaks.
Stripe rust pustules on a wheat leaf. Photo was taken on April 19, 2012 in a wheat field located in White County, Illinois.
--Carl A. Bradley
Carl A. Bradley