Ground Rules for Dicamba Use


On Friday we heard from NC State Extension Weed Science Emeritus Dr. Alan York regarding issues with Dicamba drift.  York explained that in many instances, the issue of drift onto susceptible crops has been handled between involved parties, without an official complaint that could jeopardize the continuing use of the product.

Today, York reminds us once again of the ground use for safe application of Dicamba:

“Basically, it’s just a handful of things.  Number one, use the right nozzle, they have a website on there (the label) and you can see what kind of nozzle is recommended.  The idea is use nozzles and pressures that make large droplets, which, obviously don’t drift as much.

“Keep the boom down, we don’t like to see people running across the field with a boom high enough you can stand up under it.  Twenty-four inches, max. 

“Travel speed; the labels say 15, max, that’s plenty, in my opinion, rather see less than that. Idea is that if you’re flying across the field you’re getting turbulence behind the sprayer, stuff is swirling back there.   

“Certainly, the right formulations, the approved formulations, it’s coming to light now that they’re not totally non-volatile, but they’re less volatile than the non-approved formulations.

“So, all this stuff on buffers on the labels, I think I can read as good as the next guy, and I can read the mess and understand it.  I think the bottom line is that you’ve got to use common sense.  You can see it, you  might not want to spray, if the wind is towards it.

“And watch the wind speed.  I’m really more concerned about wind direction than wind speed.  And we’ve got to watch for inversions, and it’s kind of hard to know if you do, or do not have one.  Point is, when you’ve got an inversion, you get a few particles floating around in the air, you get a lot of distance movement on an inversion.  We need to avoid that.  And that’s why all these labels say there’s a minimum wind speed of three miles an hour.  If the wind is stirring a little bit, chances are you don’t have an inversion.  But, certainly a good rule of thumb is we need to do this on ‘banker’s hours’, basically 9:00 am until 4:00 pm be a good time to spray.   Earlier than that or later than that it increases the odds you may be getting into an inversion.

“And then, drift control agents.  Some of them require a drift control agent in the tank mix.  You definitely want to do that.”

A native of the Texas Panhandle, Rhonda was born and raised on a cotton farm where she saw cotton farming evolve from ditch irrigation to center pivot irrigation and harvest trailers to modules. After graduating from Texas Tech University, she got her start in radio with KGNC News Talk 710 in Amarillo, Texas.