Defoliation Timing for Arizona Cotton

Proper timing of a defoliation event is not an easily made decision and must take into account many factors related to the maturity status of the crop. The application of harvest aid chemicals is only the last step in maximizing economic returns with an efficient defoliation. Many late and end of season practices should need to be properly managed before selecting and timing harvest aid chemical applications. These practices include proper water and N management, insect control, and others. Timely irrigation termination will set the stage for efficient crop preparation for harvest. Once the final irrigation has been applied it is time to begin selecting the proper harvest aid materials and scheduling an appropriate application timing to prepare the crop for harvest. Harvest preparation includes removal of mature foliage (defoliation), arresting juvenile growth and stimulating the opening of mature bolls.