Nov. 9 (Bloomberg) -- Robusta coffee fell on speculation the crop in Vietnam, the world’s biggest grower of the beans, will provide a buffer as a tropical storm warning was called for New Orleans, home of almost a fifth of arabica bean stockpiles.

The harvest in Vietnam that started Oct. 1 moves into “full swing” from late November, with output estimated at 19 million metric tons, down 5 percent from a year ago, according to Macquarie Bank Ltd.. The U.S. National Hurricane Center discontinued a hurricane watch for New Orleans after Ida weakened to a tropical storm in the Gulf of Mexico.

Vietnam’s harvest “will put a lid on prices for the time being,” said Ricardo Santos, head of agricultural commodities at BNP Paribas Fortis in London. “If we see arabica being affected by the weather, then it’s very likely robusta will follow.”

Robusta coffee for January delivery fell $24, or 1.7 percent, to $1,415 a ton on the Liffe exchange in London, the lowest close in two weeks. Arabica coffee for December delivery jumped 1.2 percent to $1.4055 a pound at 5:32 p.m. in London on ICE Futures U.S.

Warehouses in New Orleans that are monitored by ICE had 519,478 bags of coffee as of Nov. 5, or 16 percent of the total, according to exchange figures. Ida is forecast to miss New Orleans and head for northern Florida, according to the National Hurricane Center.

White, or refined, sugar for March delivery declined 0.1 percent to $589.50 a ton and cocoa for December delivery dropped 1.7 percent to 2,064 pounds ($3,453) a ton.

To contact the reporter on this story: Claudia Carpenter in London at ccarpenter2@bloomberg.net

Last Updated: November 9, 2009 12:42 EST