General to excessive rains across Tennessee have slowed cotton defoliation and picking for a few days. For the next ten days forecasted temperatures appear to be good for defoliation with the exception of Friday and Saturday mornings with lows predicted to fall into the upper 40’s. Highs in the upper 70’s to low 80’s with lows in the mid to upper 50’s will require some product rate adjustment to maintain good leaf drop. Folex applied alone will need to be a minimum of 6 oz per acre, however 8 oz will do a better job. Ginstar (or generics) applied alone at 3-4 oz per acre will work well. Aim (0.5 oz per acre plus 0.25% NIS) or ET (1.5 oz per acre plus 1% COC) will also get leaves off the plant. The addition of ethephon 32-40 oz per acre will help with defoliation and open bolls. The biggest draw back to using single products for leaf removal this year has been the lack of activity on juvenile growth.
Combinations of products will work better as temperatures get cooler to remove juvenile growth. Folex (2-4 oz) plus Ginstar (2 oz) plus ethephon is one popular combination. Ginstar (2 oz) plus Aim (0.5 oz) or ET (1.0 oz) with ethephon also works well. Finish is still in short supply but if you have it now is the time to use it.
June planted cotton that is still green is still a wait and see game. We need to get as much heat unit accumulation as possible, but do not want to risk a early freeze event. Continue to let this late cotton mature and hopefully with a good end to September it will mature normally. Remember 2009? Cotton will not open until it is ready. Premature defoliation and ethephon applications can hurt the yield of the the late crop. What is the signal to defoliate this crop? Just like the early crop 60% open boll is ideal. IF we have a frost predicted near the end of the first week in October we need to get the defoliant and boll opener applied 3-5 days ahead of the frost to get the maximum effect.
Contact your local county Extension office or me directly to get more information for your specific situation.
