Max Bonzo has been named Chief Executive Officer at Grupo Saenz, following the retirement in November of Aaron Saenz, who is a member of the Saenz family that owns a 51-percent stake. ED&F has owned the remaining 49-percent share since 2007.

Bonzo joined EDF just over three years ago to run its division that oversees sugar and ethanol assets. Grupo Saenz's change at the top comes as the beleaguered Mexican sugar sector struggles with weak global sugar prices that have sunk 12 percent over the last year and are below many producers' production costs.

A controversial trade deal with the United States, the country's top foreign customer, that sets quotas and prices for imports has also increased concerns about where Mexico will sell its bumper crop as the global market remains awash with excess supplies and Mexico faces worries over domestic demand due to a junk-food tax.

"The only way to survive here is to put more attention on operational efficiencies," Bonzo told Reuters in an interview.

Bonzo said the agreement will put pressure on margins over the next few years as millers look for new homes for their sweetener away from the United States.

In recent years, shipping and logistics issues have hampered the sector's efforts to increase its footprint on the global stage.

The appointment does not change Saenz's marketing agreement with ED&F Man or ED&F's share in the miller, Bonzo said. An ED&F official confirmed the change but declined to comment further.

The family has been milling in Mexico since the 1940s, according to the company's website.

Grupo Saenz operates three mills that produce about 430,000 tonnes of sugar per year, representing some 7 percent of Mexico's total sugar market, according to the company's website.

ED&F, one of the world's largest and oldest sugar traders whose roots go back to the 18th century, is also one of the most active players in the Mexican marketplace.

In 2012, it bought Bauche Group's sugar trading business during a shake-up at the French group.

It also has processing and refining operations in Chile, Venezuela, Israel, and Ukraine, and a distribution operation in the United States.

(Reporting by Chris Prentice in New York and David Alire Garcia in Mexico City; Editing by Chizu Nomiyama)

By Chris Prentice and David Alire Garcia