Follow the label. It's simple advice that, if followed, should eliminate some of the problems being seen in Roundup Ready cotton, says Keith Edmisten, Extension cotton specialist with North Carolina State University.
“We've conducted research on Roundup Ready and looked at some of the pollination problems growers have seen,” says Edmisten. “We don't see nearly as many problems as we once did. And all of the problems we saw this past year can be tied back to either spraying glyphosate off-label, spraying too late over-the-top or my making a post-directed application too high up on the plant.”
There still are a few growers, he says, who for one reason or another believe they can go off-label in their glyphosate applications without causing harm to the cotton plant. Research, however, says differently.
“We have technical data that attributes pollination problems in Roundup Ready cotton to off-label applications of glyphosate,” says Edmisten.
This research, he says, looked at — among other things — how glyphosate is translocated in the plant, how different plant parts have different tolerances to glyphosate, how flowering is affected by glyphosate applications and how pollen deposition is affected by such applications. In addition, researchers looked at the relationship between pollen viability and the timeliness of glyphosate applications.
“Most of our growers know the solutions,” says Edmisten. “We don't have nearly as many problems as in the past because most growers are paying attention to the label and not spraying past the four-leaf stage. Farmers who are post-directing glyphosate are keeping it down off the plant. In most cases where we're making post-directed applications, growers are switching chemistries to avoid potential problems. If we follow the label, we should be alright.”