Cotton plants in most fields have 14-18 nodes on the plant and 5-7 nodes above white flower (NAWF). Spotty rains fell over the past week but the forecast does not look very promising for additional rainfall.
Fortunately, the insect pressure continues to be relatively low but continue to watch for stink bugs and bollworm. For stink bugs, inspect the inside of 1-inch bolls to see if feeding caused warts or stained lint on the inside of the boll. We are in the third and fourth weeks of bloom so treat fields when more than 10% of bolls have internal feeding.
For bollworms, check squares, blooms and bolls for worms and feeding damage. A good threshold is 6% feeding damage with worms present.
Many growers have been adding mepiquat chloride (MC) to their herbicide applications. While I am not a big fan of PGR use in most fields, they do have their place but this may not be the year for them. Keep in mind there are differences between how varieties respond to MC application, and MC can hurt some varieties, especially during drought stress.
I suggest you check the following prior to a MC application.
- Plant height: If height control is the objective, how tall is the crop and what is too tall? Will it get that tall? Some fields tend to get taller while other fields usually grow a shorter crop.
- Total nodes on the plant: Many fields have 16-18 nodes on the plant. If the plants will have 25 nodes at harvest, how much taller will the plant really get? I will be surprised if most fields add 12 inches before harvest.
- Nodes above white flower (NAWF): fields with less than 7 NAWF will probably reach cutout, or 5 NAWF, in a couple of weeks. The MC application could actually get you there quicker, especially if it stays dry.
Finally, look at the terminal of the plant. Are new leaves and squares forming? In some of my variety tests, I have plants that are essentially cutout even though they have 6-7 NAWF. A MC application wont change much in this variety.
Compare the pictures below taken 6/9/22. The plant on the left is still growing but the plant on the right looks like it is done. I would definitely not spray MC to the cotton on the right.
Read “Utility of Plant Growth Regulation in Cotton Production” which can be found at the Cotton Inc Website HERE.
