Burke – Jenkins Ag News

Wheat Disease Update

It is time to make a decision whether or not to apply a fungicide to wheat. Dr. Alfredo Martinez sent us some timely information on managing wheat diseases. If you decide to apply a fungicide, applying at the flag leaf or just as the heads are popping out. This is assuming that disease is not present and you are applying preventively, if disease is present, then applying earlier is more ideal.

leaf rust

              Leaf Rust on Wheat

 Leaf rust of wheat. Leaf rust (Puccinia triticina syn P. recondita) has been reported and confirmed by Andy Shirley (CEA Mitchell county) in commercial wheat fields. While the incidence appears to be localized, recent weather patterns observed in the southern US can contribute to the dispersal and establishment of the disease. Additionally, favorable environmental conditions for leaf rust development are developing or are now in place in the state; THEREFORE wheat field scouting and monitoring should be implemented at this time. If leaf rust is present in your field, this warrants a fungicide application and the options include:

triazoles metconazole (Caramba) propiconazole (Tilt, Propimax) prothioconazole (Proline) prothioconazole + tebuconazole (Prosaro) tebuconazole-containing products (Folicur, others)

Strobilurins azoxystrobin (Quadris) fluxastrobin (Evito) picoxystrobin (Aproach) pyraclostrobin (Headline)   Mixed mode of action fluoxapyroxad + pyraclostrobin (Priaxor) flutriafol + fluoxastrobin (Fortix) propiconazole + azoxystrobin (Quilt, QuiltXcel) propiconazole + trifloxystrobin (Stratego) prothioconazole + trifloxystrobin (Stratego YLD) pyraclostrobin + metconazole (Twinline) tebuconazole + trifloxystrobin (Absolute) tebuconazole + azoxystrobin (Custodia) When leaf rust has become established in a field, triazole fungicides tend to be most effective. Strobilurins have a more preventive activity and tend to be weaker if rust is already in the field. Remember that protection of the flag leaf is of essential importance for yield preservation.

Powdery Mildew: Powdery mildew (Blumeria graminis; syn Erysiphe graminis) infections on wheat fields have been reported and confirmed recently across the state, especially in the southernmost part of the state. Weather has been conducive for the disease. Powdery mildew tends to diminish as temperatures consistently reach above 75ºF and RH falls below 85%. If powdery mildew progresses up the plant and is found in upper leaves (flag leaf minus 2) you might consider a fungicide application.