Josh Lofton, Trey Price, Boyd Padgett, Beatrix Haggard, and Steve Harrison- LSU AgCenter
As warmer and drier conditions have arrived in Louisiana, corn planting has greatly picked up. In doing so, a lot of attention has shifted away from the winter wheat to corn. However, while these environmental conditions greatly benefit corn planting, they also are near optimum growing conditions for the winter wheat crop. Much of the early and on-time planted wheat around the state should have at least a couple of nodes, if not already at the boot, heading, or flowering growth stages. Furthermore, much of the late-planted wheat has utilized these conditions to quickly progress from tillering to jointing and should also have at least a couple of visible nodes, and could be at or near boot or heading stages, especially with early maturing wheat varieties. With this rapidly progressing wheat crop and the warming environmental conditions, increased disease incidence could be a growing issue.
Earlier in the season in juvenile wheat, many “hot spots” of stripe rust were noted throughout the state. Even in resistant varieties, stripe rust may occur in juvenile wheat subsiding as plants mature. In some of these “hot spots”, stripe rust progressed far enough to trigger applications of tebuconazole (Folicur and generics) or propiconazole (Tilt and generics). Since conditions have warmed up, the ongoing stripe rust epidemic has slowed and in some cases halted. The stripe rust epidemic may re-start if the weather pattern returns to cool and wet conditions. Reports of leaf rust, a disease preferring warmer temperatures, at low levels have been coming in from southern Louisiana. Leaf rust also has the potential to reach severe levels and lower yield potential. Heavy levels of Septoria leaf blotch have been noted in early-planted wheat at the Macon Ridge Research Station. In most years this disease does not progress far enough upwards in the wheat canopy to require fungicide applications; however, Septoria leaf blotch can be severe and limit yield in some cases. Producers should scout fields for these and other diseases beginning at jointing. If fungicide applications are warranted for these diseases, there are many effective products available. Solo products or premixes containing a triazole (Group 3) are effective at slowing disease progress and preserving yield. Applications are usually not warranted or legal after wheat has begun to flower.
Due to the excessively wet spring, many want to continue to manage N in this aging wheat crop. However, we must take into consideration both the wheat conditions and age before continuing to manage N. Once the wheat crop exceeds the 2 node stage, the economic return for additional N has diminished greatly. Furthermore, once the crop has reached flag-leaf, little to no additional benefit can be gained from additional N applications. Another aspect to consider are the crop conditions. With the overall wet and frequent cool conditions, certain wheat field’s yield potential has decreased. This does not mean that this year’s wheat crop cannot be productive but it does mean that additional N is probably not warranted.
For further questions or comments please contact your local extension agent or state specialist
Josh Lofton, Wheat State Specialist, firstname.lastname@example.org
Boyd Padgett, Wheat Pathologist, email@example.com
Trey Price, Field Crop Pathologist, firstname.lastname@example.org