The hardships facing groves in Florida, America's biggest citrus producing state, are so severe that orange juice looks likely to revive its rally.

Washington's prediction of a 16% slump in Florida's orange crop this year, an estimate which "outstripped even the most pessimistic private forecasts",  might prove to have been "a bit of a watershed" for juice futures, a report from BNP Paribas Fortis said.

More than weather damage, an estimate of lower fruit numbers per tree appeared to reflect the spread of citrus greening, a fatal and incurable bacterial disease spread by insects.

"One of the symptoms is reduced fruit yield, and it may be that the considerable drop in the average fruit per three this season is a direct consequence of this devastating disease," the note said.

With consumption being revived by economic recovery, the orange juice market looked set to retest the 13-month high of $1.17 a pound set last week.

"[Juice] prices… ought to improve steadily in coming weeks, given that demand is slowly recovering to pre-recession levels and that the longer-term supply outlook remains fraught with uncertainties," the report said.

Farmers quit

Citrus greening - which is also a serious problem in Brazil, the world's top-ranked orange producer - was first discovered in Florida a decade ago.

"Florida's orange output has never recovered to levels seen before these hurricanes," the report said.

Urbanisation has also swallowed up many groves, echoing the changes which have switched citrus farms for homes and industrial estates in California's Orange County, while falling prices in 2007 and 2008 also encouraged many growers to quit.