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The Art of Cotton Defoliation

By Will Scott


Growing up in the heart of the Mississippi Delta, I still remember the pungent odor of cotton defoliations swirling through the air early in the morning as I walked to school. For a large part of the country, fall is synonymous with leaves falling from trees and other vegetation. However, in the South, the smell of defoliants was an abrupt signal that summer was ending and fall was starting.  

Cotton defoliation, a risky but necessary practice in cotton production, is the process of removing leaves artificially. As leaves become mature they can, and will, abscise naturally. However, removing leaves through chemical applications offers many benefits such as efficient and faster picking, quicker drying of seed cotton, eliminating the main source of stain and trash, increasing lint grades, preventing boll rot, easing boll opening, reducing moisture, and improving storage. In addition to defoliants, chemicals that are added can control regrowth and open green bolls. 

The art of cotton defoliation can best be described as one the most subjective decisions in cotton production with respect to product selection, combination, and rate. Within these factors lie the variables that must be considered prior to application. Some of the variables that impact the efficiency of leaf drop in cotton are variety, soil texture, soil moisture, environmental temperatures, crop height or canopy, three to five days’ rain forecast, and application coverage. Due to the sensitive nature of how these variables impact products, I will keep to it to the basics. 

Application Timing

There are multiple methods for deciding if it is time to apply defoliation but regardless of what method you choose, fields should be scouted thoroughly for overall maturity level. Using multiple sampling techniques often gives a better depiction of the crop’s maturity. Typically, defoliation programs are a two-step approach due to dense canopies and crop height. Using a ground applicator, hollow cone tips, and increasing GPA tend to be the most efficient application methods. Product decision can further be separated by three factors: temperature (above or below 80 F), 2e-growth potential (high or low), and if a boll opener is needed. 


Harvest Aid Rate/Acre Max Per/Season Rainfast (Hours) Pre-Harvest Interval (Days) Estimated Min Temp Mature Leaves Juvenile Growth Re-Growth Prevention Boll Opening
1.6-6.4 oz 9.6 oz 24 5 65 F Excellent Excellent Excellent None
16-24 oz 24 oz 1 7 60 F Excellent Good Fair None
21-42 oz 42 oz 6 7 60 F Good Poor Poor Excellent




Will Scott

As Pinnacle’s Tech Services Manager, Will Scott brings his industry expertise to the organization’s product offerings. Since joining Pinnacle Agriculture in 2012, Will works closely with research and development, proprietary brands and procurement teams to ensure we are delivering the best possible product to our customers.