We got extremely hot and dry the last few weeks of the growing season which pretty much shut down our dryland cotton production. The conditions caused much of the top crop to be stunted and very poorly developed. It also shut down terminal growth which would have been good for defoliation and boll opening.
However, we were not that lucky. A few recent rains and slightly milder temperatures caused most of our cotton to resume growth. Now we have fields across the region that look like the picture below.
Not only do we have to try and open bolls and defoliate the crop, but now we have to control the young tender shoots that are present. Every field will be a little different than the next but most of the ones that I have been in would benefit from a 3-way mixture. Something for boll opening plus defoliation and regrowth control.
We don't want to spend any more money than we have to but we also don't want to make a mess and have to put the sprayer back into the field a second time. let's say that the 3-way mixture of thidiazuron + diuron + ethephon costs you $12.00 per acre. What would happen if you wanted to save $2 -3 dollars by leaving out the thidiazuron? Most likely the young tender regrowth in the field would not be removed and you would need to retreat. Instead of saving $3 you end up spending more than $5, plus the time to spray and the delay in harvest.
Like I said in the beginning every field and every situation is different but in most cases I feel that the 3 way mixture of boll opener + defoliant + regrowth control is going to be needed this year.