What is in this article?:
- Georgia-based researcher looks at dealing with glyphosate-resistant pigweed with non-selective/wick applicators.
- Types of applicators discussed and critiqued.
- Report from the Pigposium.
NSAs work best in peanuts, said Prostko, because the crop only gets 12 to 18 inches tall. That allows a good height differential between the crop and weed.
Recently Gramoxone Inteon received a 24-C label for peanuts in Florida, Georgia and South Carolina for the management of Palmer amaranth and beggarweed.
For the Mid-South, the big question is “how will the NSAs work in soybeans and cotton? My biggest concern is that soybeans and cotton are much taller than peanuts. You need a height differential (between the crop and weed) to get a maximum application to the weed and minimal application to the crop.”
And that brings up crop response. When using an NSA, “you must worry about drippage.”
Also: what products are legal to use in soybeans or cotton with an NSA? “Right now, I don’t know anything that’s legal other than glyphosate.”
All the NSAs aren’t equal, said Prostko.
“Some are more effective. Some are more expensive, as well.”
Farmers need to ensure at least a 50 percent wipe on a plant for an NSA to be effective. “That means that if you have a 50-inch-tall pigweed, that applicator needs to be set at 25 inches, or less.”
Remember, “you’re driving a tractor, not a star ship. As much as we’d like to be Captain Kirk, the faster you go the less effective the applicator will be. In most of our research we’re driving 3 or 4 miles per hour — maybe 5 miles per hour. Slower is better.”
If you use a wiper, it needs to be on the plant before seed is formed. Based on newer data, viable seed can be produced as early as two weeks after pollination — target applications for that time period.
“If you already have seed on a plant, you’re wasting your time with NSAs because it is likely the Gramoxone won’t affect seed germination.”
Read the operator manual, advised Prostko.” There are some good things in there, problems you can avoid.”
Maintaining stewardship “is extremely important. Again, we’re dealing with a (product) concentration that’s much higher than normal. If you’re using Gramoxone in a burndown prior to planting, that’s 2 pints per acre in 10, or 15, gallons of water. That’s roughly a 2- to 3-percent solution of Gramoxone. With the NSAs, you’re looking at a 50 percent solution. So, you must be more cautious on how you mix, where you mix, how the mix is transported, etc.”
Prostko related a recent NSA learning experience and the importance of minimizing drips.
“Because we didn’t have anything labeled, I hadn’t done anything on a large scale in growers’ fields. Once we got the label for peanuts, though, I decided to take a rig into a local grower’s field to see how it would work.
“The good news is most of the problems have been addressed by the manufacturers and are fixable. But if you’re using one of these, they’re likely to drip. You need to work with the machine — it’s part art and part science — because it takes a little experience to figure out how best to set up the machine and see how it works.”