Glyph-resistant horseweed: Syngenta announces fall application label for Envoke herbicide

Syngenta announced today that Envoke herbicide's label has been amended to include fall and early winter application in cotton, aimed at residual control of glyphosate-resistant horseweed and other winter annuals.

“Fall applications are going to be one of the more consistent ways of controlling horseweed,” said Dr. Larry Steckel, University of Tennessee extension weed scientist who was quoted in the release. “Trying to burn down large horseweed that got its start the summer of the previous year or early in the fall is going to be hard with anything. If a grower catches these populations early with a residual herbicide, he is going to be way ahead of the game.”

Applied at 0.10 ounces per acre, Envoke offers pre-emergent residual control of glyphosate-resistant horseweed and tough winter annuals including shepherd’s-purse, henbit and annual bluegrass, the release said.

Envoke at 0.10 ounces per acre may be tank mixed with Gramoxone Inteon, Touchdown HiTech, Touchdown Total, Roundup brands and other glyphosate products as well as synthetic auxin herbicides such as dicamba and 2,4-D. Always add 0.25% v/v NIS to Envoke applied alone or in tank mixes for emerged weed control, the release specified.

“We’ve looked at fall-applied products at various rates for two years,” said Steckel. “We have gotten very, very good residual control of horseweed with low rates of Envoke.”

Syngenta and university cooperator trials have confirmed that even in heavily infested fields, a fall application of Envoke provides effective knockdown and long-lasting residual activity, setting the stage for a clean start at planting and improved crop emergence, according to the release. Cotton may be planted three months following a fall/early winter application of Envoke. Consult the Envoke label and labels of all tank mix partners for rotational restrictions and application requirements.

“We have been looking for a way to thin the horseweed populations in the fall so they are manageable in the spring. Although Valor provided sufficient control through the end of January, it was breaking by mid-March. Envoke was certainly superior in level and length of control,” said Dr. Dan Poston, Mississippi State University extension weed scientist.