Cotton defoliation time is here. Dr. Hand was provided some information on cotton defoliation. His defoliation recipe for this week is
3.2-4 oz/acre thidiazuron (Dropp) (go higher end for higher regrowth potential)
8-10 oz/acre tribufos (Folex/DEF) (higher on lower temp days)
32-42 oz/acre ethephon (Prep/Setup/SuperBoll)
The first question is last effective bloom date on later planted cotton.
Dr. Porter showed this illustration yesterday at the cotton and peanut harvest meeting in Moultrie. As the crop moves through the weeks of bloom and begins to approach the 8th week of bloom, it is time to start monitoring the field for maturity and specifically scouting for cutout. The table below corresponds to the image of the cotton plant (Both developed by Whitaker et al. 2019) and represents the value of seed cotton and fiber by location on the cotton plant. The short conclusion to this is that the majority of value from the cotton plant comes from the first position bolls developed on nodes 10 and below. Value by location is important when discussing irrigation termination and defoliation. In this case we are going to focus specifically on irrigation termination. As most who work with cotton know, the first bolls that we will rot, or lose is typically the bottom bolls. Thus, we want to manage our irrigation so that we do not make increase the likelihood of disease causing boll, yield, and profit loss.
Source : uga.edu