The value of average has always impressed me. A great example of this would be growing degree days for this 2017 season thus far. We started planting mid-April with daily high temperatures staying in the low-to-mid 70s during April 13th thru the 20th. After a lot of corn was planted, we dropped our temperature down to highs only getting to the upper 40s to lower 50s for eight days during the end of April and the beginning of May. Even with the cold spell we experienced early this spring, we are trending fifty to seventy GDD above the three-year average.
Things that growing degree days affect include the timing of scouting Black Cut Worms. Flight of cut worm moths this year peaked mid-April. After moths land and lay eggs, it takes four to five days for larva to hatch. The Larva will grow and start feeding on corn around the 300 growing degree day mark and can proceed in feeding on corn leaves and stalks near the soil surface. When scouting, start in areas that had vegetation growth on it in late April and early May. The moths will pick out these areas to land and lay eggs. As the black cut worms go through this part of the life cycle, they have the capability to clip off four corn plants in their larva stage. This can change the look of a heavy infested field in days. Black cut worms will continue feeding and damaging corn plants until the shank of the corn plants become large and less tender, not allowing the cut worm to penetrate the plant.
Remember, as we go through the growing season with extremes it is not always the highs and lows that effect the growing season, but the averages that complete the season.
Contact your FS Crop Specialist for all your agronomic needs.
Jason Schnell serves the FS System as GROWMARK Senior Field Sales Agronomist. He can be reached at [email protected].