Recipe for the week:
- 3.2 – 4 oz/acre thidiazuron
- 8-12 oz/acre tribufos (higher towards the end of the week)
- 32-42 oz/acre ethephon (higher towards the end of the week)
Looks like we’ve got a slight change in the weather this week, which may mean adjusting our defoliation plans. For the most part, we’ll go from the low 90s into the upper 80s through Wednesday, then temperatures look to drop into the upper 70s. By Friday, some places may even see lows in the 60s. Don’t let that cool-down fool you, though. If the forecast holds, it looks like we’ll warm back up some next week. As most of you know, cotton is a lot easier, and usually cheaper, to defoliate when it’s warm. Once temperatures cool down, we may need higher rates and potentially a little more patience between application and harvest.
So, if it were my cotton, here’s how I’d approach this week:
- If I had cotton ready to defoliate and was ready to pick it, I’d try to spray today (Monday) or tomorrow (Tuesday).
- If I couldn’t get to it by then, I’d probably hold off and see what next week brings.
Why wait? Mainly because the recipe I’d use Monday or Tuesday would be different from what I’d be comfortable using Thursday or Friday. Then, if temperatures warm back up like they’re supposed to next week, I’d probably go back closer to my original recipe. Today, WALB says there’s also a small chance of rain throughout the week, so keep that in the back of your mind as you make plans. If I decided I needed to spray Thursday or Friday in the cooler weather, I’d probably start looking at a Ginstar-type product. I’d be thinking somewhere around 6 to 8 oz/acre plus ethephon. Adding a little thidiazuron wouldn’t hurt either, especially in fields with a lot of regrowth.
One thing I’d like to note is water volume and droplet size; both are important. When it comes to defoliation, more water is generally your friend:
- 10 GPA is better than 7.
- 15 GPA is better than 10.
- 20 GPA is better than 15.
Since a lot of folks are already set up to run 15 GPA, that’s probably the sweet spot I’d shoot for. Larger droplets, like what we get with some dicamba tips, can make good coverage harder and increase the chances of defoliation issues. Increasing your water volume can help make up for some of that. Whatever you decide to do this week, don’t forget the lessons we learned from UPW; these products need to stay on target just like everything else.