Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
Continue scouting wheat for powdery mildew. The cool weather has been ideal for disease development. In cases where too much nitrogen was applied or extra carry-over from last year was not taken into consideration, resistance can be overcome. Lush wheat should definitely take priority when scouting. In areas that had good moisture in the fall keep an eye out for wheat spindle streak mosaic virus. This virus is vectored by a root infecting fungus that needs plenty of water in the fall when the initial infection takes place. We have had reports of it occurring but have not seen any plant samples yet in the lab. Wheat generally grows out of it once warm weather gets here and stays. Symptoms on leaves appear as yellow-green mottling, dashes, and streaks. It can occur widely in fields not just wet areas. Wheat soil-born mosaic virus can often be confused with WSSMV but is generally more limited to wet spots in the field.
Wheat spindle streak mosaic virus