Additional Thoughts on Early Cotton Defoliation
Keith Edmisten and Guy Collins
Growers are starting to ask questions about defoliation. The questions usually include a reference to not wanting to spend to much money due to the low cotton prices. The other common part of the conversation is that the crop is early and mature, so it should be easy to defoliate, right? Both of these points are legitimate, but need to be well thought out before making decisions.
An early crop is often easier to defoliate IF you do not have regrowth. Defoliation occurs under higher temperatures conditions that favor activity of many defoliants and all the common defoliants work pretty well on mature leaves. Unfortunately this early crop is at least partially due to dry weather at the end of the season. This situation leads to the potential for tremendous regrowth pressure with recent rains.
Regrowth is very difficult to defoliate. The best way to deal regrowth is to remove it before it becomes too heavy and prevent further regrowth. The only material we have that prevents regrowth is thidiazuron. Growers looking to reduce rates due to higher temperatures at defoliation or because the crop is early and mature, need to keep this in mind before reducing thidiazuron rates. If you are using premixes that contain thidiazuron and diuron, you should consider adding additional thidiazuron to increase regrowth control.
Can you reduce rates of defoliants on early cotton that is cut-out and mature? Sure, but if you have moisture and can’t pick very quickly you may have more of a mess than you started with due to regrowth if you don’t use appropriate rates of thidiazuron