Plant Growth Regulator Use in Cotton

Generally speaking, the 2012 crop is ahead of where we typically are at this time of year.  Much of this can be attributed to planting earlier than usual due to warm weather conditions earlier in the spring.  Blooms have already began to appear in several fields and many more will start blooming over the next ten days to two weeks.  For “average” planting dates in Mississippi, the arrival of blooms often times coincides with the fourth of July.  Although the exception rather than the rule, one grower in the north Delta reported finding white blooms during the last days of May and first days of June.

Given the time frame we are on with the crop this year as well as rainfall throughout much of the state over the past week, applications of plant growth regulators are beginning to go out.  Plant growth regulator application is much like many other aspects of farming, each person has a particular way they like to do it.  While I would encourage to keep doing what has made you successful in the past, I would also encourage you to give some thought to product selection.  Myself and colleagues throughout the Cotton Belt have conducted extensive research on plant growth regulators over the past several years.  In our research, we have not found any one product to have an advantage over another with respect to control of vegetative growth or yield responses (see table below).  In general, yield responses from plant growth regulator application are more likely to be seen during growing seasons that are truncated due to poor weather conditions, etc. whereas yield responses from plant growth regulator application during long, favorable growing seasons in less likely.  While we have found no yield advantage from PGR application, reduced plant height is beneficial.  Reduced plant height allows for greater penetration of broadcast applied herbicides, insecticides, harvest aids, etc.  In addition, reduced plant height also increases picking efficiency at the end of the year.  To that end, I would encourage you to use whatever product best fits your operation.  If that means the rock bottom cheapest product, then so be it.  However, if you would prefer to use a product that has lower use rates which means less material to store, handle, and mix that is perfectly acceptable.