A few growers and agros are asking questions about the appearance of the occasional tall plant in some fields. These plants have become more noticeable since cut out, because when the bulk of the field stopped growing these plants pushed on. Other features of these plants tend to be upright upper branches with low fruit load. These characteristics have earned these plants the names of ‘semi-sterile’ or ‘crazy top’, but what causes it and is it cause for alarm?
A single cause for this weird growth has never been identified, because it may result from several possible environmental conditions that alter the plant’s growth. ‘Crazy top’ has been associated with; both nutrient deficiencies and excesses, extremes of hot or cold temperature affecting growth, either excessive moisture or soil compaction or increased plant-plant competition all limiting root growth and leading to taller plants with reduced boll load and, in work undertaken by Greg Constable, a possible viral issue. About the only thing that has been ruled out as to a cause is that it is not seed based.
Stephen Allen commented a decade ago that these symptoms were more noticeable in the 2002/03, 06/07 and 12/13 seasons. Some of you might have insights into similar aspects of these seasons that might give you a stronger belief in one possible cause over another. However, in all these years and like this, these seasons had slightly less ha of cotton than the previous year, so perhaps it is simply more obvious than the year before? Regardless of why we notice it more in some years than others or what the potential cause is, ‘crazy top’ is nothing to get alarmed about. It’s simply a cotton plant responding to something in its environment in a way that a predominantly indeterminate plant can.
Cotton is simply quite amazing, and we still don’t know everything about it. Like Maya Angelou said, “If you are always trying to be normal, you will never know how amazing you can be.” So perhaps we can just accept that the occasional cotton plant is simply not normal?
