This year has been a cotton season of extreme heat and drought for Johnston County, N.C., cotton, notes Extension agent Tim Britton in his latest Ag Report, released Oct. 17. Similar conditions have been the case for a large number of cotton growers in other eastern North Carolina counties as well.
Britton notes that many Johnston County cotton fields that have suffered these hot, droughty conditions have responded in a particular way. They have open bolls at the bottom of the plant, he says, mature bolls in the middle of the plant, and few or no bolls at the top of the plant.
"Considering our last effective bloom date is August 20, current blooms/squares typically add no value to the crop," Britton says. "The last effective bloom date can be defined as the last date a bloom has potential to become a mature, harvestable boll."
Cotton planted by North Carolina growers had a number of weather challenges this year, not the least of which was the battering of the crop by Hurricane Irene, a powerful storm that made U.S. landfall over North Carolina's Outer Banks on August 27 and then proceeded northward to pound Virginia and a number of other states in the Northeastern U.S.
Britton notes Irene's battering resulted in ethylene production in the plant and defoliation of leaves, as well as stimulating some mature boll opening. As a result, Extension cotton experts at N.C. State University are recommending growers defoliate the crop in stages this season.
"With the warm weather and high moisture levels we experienced in the first part of September and potential plant available soil nitrogen, defoliated cotton not picked within 10-14 days following treatment may develop significant re-growth," Britton says in his report. "Consider harvest capacity. In general, defoliate only the acreage that can be harvested within 10-14 days following treatment."
Britton points out that adopting this kind of strategy diminishes lint weathering losses and may possibly save on grade discounts. "While keeping the picker busy may be important, a 30+ day high re-growth potential exposed crop is not desirable," he says. "With this in mind, 1.6 fluid ounces/acre of Dropp, Freefall, or Thidiazuron 4 will provide re-growth control for 10-14 days; 3.2 fluid ounces/acre of Dropp, Freefall, or Thidiazuron 4 will provide re-growth control for 14-21 days."