Monsanto is expanding its Roundup Ready (RR) Plus weed program with Amvac’s Impact herbicide in 2012. The agreement between Monsanto and Amvac Chemical Corporation was announced today.

Impact is the first postemergence herbicide added to the Monsanto program for control of emerged broadleaf and grass weeds. Impact offers another active ingredient to the program, providing more effective weed control. The active ingredient is topramezone and is an HPPD inhibitor that is effective in weed resistance management, according to Monsanto.

“This agreement creates value and choice for farmers using the Roundup Ready Plus system by offering another tool to effectively manage weeds on their farm,” reports Tyler Hackstadt, Monsanto’s selective chemistry manager.

The Monsanto agreement offers Amvac an expanded sales market for its Impact herbicide. Amvac is a subsidiary of American Vanguard Corporation. For more information about Amvac, visit For more information about the Roundup Ready Plus weed management solution, visit