Syngenta AG (NYSE: SYT ) said former DuPont Co. (NYSE: DD ) director Erik Fyrwald will take over as chief executive officer to steer the Swiss agrochemical maker through the final stages of its $43 billion takeover by state-owned China National Chemical Corp. Currently CEO of U.S. chemical distributor Univar Inc., Fyrwald will replace John Ramsay, who has run Syngenta on an interim basis since November after the sudden departure of Mike Mack, the Basel -based company said in a statement on Wednesday. Fyrwald left DuPont after 27 years in 2008 and joined Univar four years ago. Syngenta AG, an agribusiness company, engages in the discovery, development, manufacture, and marketing of a range of products designed to enhance crop yields and food quality worldwide. E. I.