Estimated stalk borer development would indicate that growers from southwest to northeast Nebraska should be making treatment decisions based on field scouting. Figure 1 shows accumulated growing degree days since January 1.

Based on research at Iowa State University, stalk borer egg hatch begins at about 575 DD and ends at 750 DD. Souting should begin when 1,300-1400 DD have accumulated. This corresponds with the beginning of larvae moving out of grassy hosts. Determine the need for treatment when 1,400-1,700 DD have accumulated.

For more information on stalk borer life cycle and scouting recommendations, see the May 11, 2012 CropWatch article, Timetable for Common Stalk Borer Scouting Moves Up.

Robert Wright
Extension Entomologist, Lincoln