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Defoliation and Harvest Aids
Defoliation is the shedding of cotton leaves that usually occurs when the leaves become physiologically mature. Leaf shedding (abscission) results from activity of special cells at the base of the leaf petiole where it joins the stem. This area is called the "abscission layer." Defoliation can be caused by a light frost, disease, drought or mineral deficiency. It also can be artificially induced by the use of certain chemicals called "defoliants." In situations where canopies are dense and there are significant numbers of green bolls that need to be opened, two applications are often needed. Often, you should plan for a two-pass approach instead of getting less than desirable results from an expensive one-shot approach requiring a second application to finish removing leaves. The goal of the first application is to remove as much foliage as possible exposing the unopened bolls without causing desiccation.
What are the benefits from defoliation?
- Removing leaves
- Eliminating the main source of stain and trash
- Better lint grades
- Preventing boll rot
- Faster and more efficient picker operation
- Managing maturity, allowing harvest earlier in the season
- Quicker drying of dew, allowing picking earlier in the day
- Reducing moisture
- Improving storage in modules
Cotton Harvest Aids - guide for selection of harvest aid chemicals (pdf)
Cotton Defoliation Timing - a guide for determining the proper timing of harvest aids (pdf)