Monsanto Company Chief Executive Officer Hendrik A. Verfaillie resigned as CEO, president and director of the board, effective immediately.

Board Chairman Frank AtLee III will serve as interim CEO while a search is conducted, according to the company.

Verfaillie was with Monsanto for 26 years. He led the company through a merger with Pharmacia & Upjohn, a subsequent initial public offering, followed by the completion of the spinoff from Pharmacia earlier this year.

"I want to be certain that Monsanto’s shareowners understand that Hedrik’s resignation was mutual. Hendrik and the board agreed that the company’s performance during the last two years has been disappointing," says AtLee. AtLee also said the board members continue to support Monsanto’s business strategy, and there was no impropriety involved in Verfaillie’s decision to resign.