If the crop is defoliated too soon, yields, quality and profits suffer. On the other hand, depending on the location and the field condition, delaying defoliation may increase likelihood of additional insect problems, or delaying harvest into bad weather which will effect yield and profits. That is why defoliation decisions must be based on the crop and the crop environment. Plant maturity is perhaps the most important factor, but other factors such as picking capacity, custom harvesting, and weather are also important.
Defoliation is an important management practice associated with high yields and high quality cotton.
The decision as to how and when to remove the leaves and open the bolls appears to be one of the more difficult tasks confronting a cotton grower. There are so many variables involved that the results of harvest aid applications are often unpredictable and sometimes even undesirable. You would think that after more than 40 years of research in this area we could obtain desirable results under all circumstances. However, this is not always true, and we often have failures. Thus, defoliation has come to be considered as much art as science.