On-farm plot research indicates that the use of Staple herbicide early in Roundup Ready cotton can give cotton producers a jump on weeds and reduce trips through the field, says DuPont Crop Protection, the makers of Staple.
Richard Edmund, field technology representative for the company, pointed to large-plot research conducted by Chuck Farr, a crop consultant with Mid-South Ag Consultants, Inc., on the farm of Mike Carlson, Crawfordsville, Ark. In the research, the number of trips across the field were reduced or the cooperators were able to reduce the rate of Roundup by including Staple in the weed control program.
Ironically, bad weather prevented Farr and Carlson from carrying through on a plot in which no herbicides were used other than Roundup.
But Farr pointed out that right down the road from the plots, a grower made six Roundup applications on his Roundup Ready cotton, one at planting, one at the two-leaf stage, one at the five-leaf stage and three more times with straight Roundup applied with a hooded sprayer. “The most applications we made in any of the Staple applications was three,” Farr said. “And it really saved us on some weed control.”
Farr pointed out that under real-farm conditions, a sudden storm or rain can quickly shorten or eliminate the window for two over-the-top applications of Roundup on Roundup Ready cotton. “It's important to get a residual herbicide out, especially with the weed spectrum we have.”
“There are some places to use Staple,” Carlson added. “You're going to have to know what your weeds are. Every field is not going to be the same. But we have to cut costs everywhere we can, so we have to scout these fields real close.”
The best plots in terms of weed control, he said, were those containing Staple early — either pre-emergence alone or Staple with Roundup Ultra, post-emergence prior to fifth leaf.
Morningglory pressure was heaviest in a plot treated with flometuron at 1.75 pints per acre, pre-emergence, followed by a post-application of Roundup Ultra at 2 pints per acre at three-leaf, a post-directed application of Roundup Ultra at 1.5 pints per acre plus Staple at 0.6 ounce per acre and a layby application of Bladex plus Diuron.
A plot that did a good job of weed control was Roundup Ultra plus Staple at five-leaf cotton followed by Roundup post-directed with a hooded sprayer followed by a layby application of Bladex plus Diuron.
Plot tests further south in St. Joseph, La., showed three things, according to Stephen Crawford, consultant with Crawford AG, Inc. “The combination of glyphosate and Staple in Staple Plus will do a better job of controlling larger morningglories than straight glyphosate. Also, there are glyphosate-tolerant species, like hemp sesbania, that Staple Plus does a lot better job on than glyphosate alone.
Crawford says that the residual activity of Staple for control of small-seeded broadleaves such as prickly sida and spotted spurge as well as annual grass control and suppression of morningglory, is important for Louisiana cotton producers.
“In this area, our focus has been on multiple applications of glyphosate, two shots over-the-top within that early window of opportunity. That works fine if Mother Nature doesn't throw you a curve.”
Crawford pointed out that producers are more “wind conscious than ever” these days, especially when many adjacent crops are sensitive to Roundup. “This, plus rainfall makes making two timely applications of Roundup within a three-week period very difficult.”
DuPont offers a pre-packaged system, Staple Plus, containing Staple in a dry, water-soluble bag, surrounded by liquid glyphosate in a single plastic jug. Each co-pack treats 10-acres.