We are now seeing some of our earlier dryland cotton cutting out on us. You can drive by fields and see the white flower at the very top of the plant. We also have some bolls opening on the bottom. This cotton is for sure done, and if it was going to start back going, it should have done that by now. But it is good to see all the flowers too.
Cut-out is basically the plant is ceasing vegetative growth and will now put its energy in finishing reproductive growth – filling out bolls. There are a few things to look for with cut-out. The first is 3 to 4 nodes above white flower (NAWF). For us down here, 3 NAWF is more accurate. UGA Cotton Agronomist Dr. Jared Whitaker reminded me of something I didn’t know. You will also see stems thinning in terminal growth when cutout occurs. And finally, lots of squares will be aborted. Dr. Whitaker says the aborted squares are the physiology of the plant telling us its cutout.
Do we have time to make?
UGA has worked on trying to determine when our last harvestable boll occurs. For us, it is going to be around September 15th. If the flower sets after that date, we do not have time to harvest that boll. Keep in mind; there are 3 weeks between squaring and bloom. To make 1,000 lbs of cotton, Dr. Whitaker says we also need 3 weeks of bloom. That sounds like a lot but it’s possible. Three weeks of bloom is also equivalent to 7 nodes. So, unless we have already started back going, we’re past it now.
Are plant bugs affecting late square retention?
We’ve been seeing squares abort now for a while as temperatures have increased. A very good question concerns effects of plant bugs. Once we get past 1st week of bloom, it’s hard to prove plant bugs are causing square abortion. UGA Entomologist Dr. Phillip Roberts says you can find a square that has recently fallen off the plant and slice it open… If it’s mushy and rotted, it’s not plant bugs. If the square has “localized damage” (similar to lint stains from stink bugs), plant bugs are possible. But even when parts of a field are stressed, plant bugs are going to move to less stressed, green and healthy plant parts. What we are seeing now is squares aborting due to plant choosing to put resources where it needs them most. We see them abort more when we go without rain, then rain comes, the plant will then drop lots of squares.