Alyssa Koehler, Extension Field Crops Pathologist; akoehler@udel.edu
Other than a few patches of minor powdery mildew, the cool temperatures and multiple frost events throughout March have kept disease levels low. However, as temperatures warm up over the next few weeks, continue to scout your fields to monitor for disease. Nitrogen applications provide a good opportunity to scout for foliar diseases like powdery mildew and leaf blotch diseases. While you can make a fungicide application at 2nd nitrogen application or flag leaf, remember that fungicides applied at this timing will not provide control of Fusarium Head Blight (FHB) and deoxynivalenol (DON) levels. The main priority of early season fungicide application is to protect the flag leaf. In most years, foliar diseases do not approach the flag leaf until the flowering stage, so a well-timed fungicide to manage FHB is typically effective for common foliar diseases. If you are not seeing a lot of early season disease pressure in your field, waiting to apply fungicide at flowering should protect the flag leaf and tissues contributing to wheat yield. In next week’s issue, we will discuss FHB cultural and chemical management options including optimal timing for FHB fungicide application.