Giant ragweed’s characteristics make it difficult to consistently control with single applications of PRE or POST herbicides, or multiple applications of herbicides with the same mode of action. The most effective herbicide programs combine PRE and POST herbicide treatments, and 2 or more herbicide modes of action*. Growers can see giant ragweed emergence from early spring to June, even into July in some cases. Find POST herbicide recommendations for managing giant ragweed here.
*As reported in the Glyphosate, Weeds, and Crops Series: Biology and Management of Giant Ragweed publication, endorsed and reviewed by Glyphosate, Weeds and Crops group in which members are university weed scientists from major corn and soybean producing states.