Orange juice jumped 6% in New York to within 5 cents of a two-year high after Washington slashed its estimate for Florida's citrus crop because of damage caused by last month's "arctic" weather conditions.

The US Department of Agriculture cut its forecast for the orange harvest in America's biggest citrus-producing state by 6m boxes.

At 129m boxes, the crop is now on course for a year-on-year drop of 21%, after freezing temperatures added to the problems of a crop already beset by disease and the temptation of grove owners, during periods of low prices, to sell out to housing and golf course developers.

The department, whose estimates were based on grove assessments late last month, said it would undertake follow-up surveys in mid-March.

'Completely ruined' 

"An arctic cold front delivered several nights of sub-freezing temperatures to Florida early in [January]," the USDA.

In citrus groves, "caretakers irrigated heavily and accelerated harvest" to limit the threat of frost damage to a crop which was already notable for below-average fruit sizes.

"Fruit size decreased for the early, mid-season, and navel varieties, while fruit drop increased," the USDA said.

Market reaction 

In New York, orange juice for March delivery jumped 6.5% to 143.00 cents a pound in early deals, within 5 cents of the two-year high set two weeks ago.

The contract closed at 137.65 cents a pound, up 2.5% on the day.

Florida was, in 2008-09, responsible for 76% of US orange production.