BASEL, SWITZERLAND — Michael Mack has decided to step down as chief executive officer (CEO) and executive director of Syngenta and will leave the company at the end of October. Mack’s decision comes two months after the Swiss company rejected a $47 billion takeover bid from St. Louis, Missouri, U.S.-based rival Monsanto Co.

John Ramsay, chief financial officer, has been named interim CEO of Syngenta until the appointment of a new permanent CEO.

“On behalf of the board, I should like to thank Mike for his very significant contribution to Syngenta,” said Michel Demare, chairman of Syngenta. “Under his strong strategic and operational leadership Syngenta developed and implemented its innovative integrated strategy and the commitments behind The Good Growth Plan. His R.&D. investment strategy has enabled the company to strengthen its leadership and the rich pipeline in crop protection, seeds and traits will continue to produce results in the decade to come.”

Mack joined Syngenta in 2002 as head of crop protection for the NAFTA region. He later was promoted to chief operating officer in 2004, and he has been CEO since January 2008. Prior to joining Syngenta, he was president of the Global Paper Division of Imerys SA, a French mining and pigments company. Earlier, he held various roles with Mead Corp.

“I believe that this is an appropriate time for the company to benefit from the perspectives of a new leader,” Mack said. “I would like to express my appreciation to colleagues, customers and the many partners around the world with whom I have worked over the past 14 years. Syngenta is a great company with outstanding prospects as the only truly integrated global player in the industry. While the current market conditions are challenging, I am confident that the strength of the company’s products, promising pipeline and talented people will deliver significant value in the years ahead. I wish John every success in his new role and am sure he will make a major contribution.”