Bebedouro, Brazil, Feb 17 - A perennial battle against disease and despondency over low prices are turning orange farms in world top juice exporter Brazil a paler shade of green.

Many growers in the main orange state of Sao Paulo have been pulling out their dark-leaved citrus trees and planting sugar cane which they say is hardier and usually more profitable.

"Today we are paying to produce oranges ... We are selling to processors at 10 reais per (40.8 kg) box," said Pedro Botamedi Sobrinho, farm manager in Bebedouro, one of the main orange-producing towns in the north of Sao Paulo state.

Sobrinho said his costs amounted to around 14 reais a box.

The equation has prompted many small producers to switch without hesitation to cane, but others prefer to watch and wait, aware there is usually no turning back once orange trees -- which only bear fruit after four years -- are uprooted.

Sources at Bebedouro's Credicitrus bank, which evolved from an orange grower cooperative, say loans to the cane industry could surpass sums lent for orange growing within a few years.

"All of this used to be orange groves," farming ministry agronomist Walkmar de Souza Pinto said, pointing to swathes of leafy cane stalks on a drive along main roads around major orange town Bebedouro in northern Sao Paulo.

Brazil's Portuguese colonists brought orange trees here from China five centuries ago to ward off scurvy as they roamed the seas, but it was sugar cane the "conquistadors" chose to be their new territory's first industrial activity and export.

CANE'S SECOND WIND

Chief among orange growers' complaints is their claim that the four main processors, who grow nearly half the oranges they process on industrial plantations, collaborate to pay growers less. The justice ministry says it is investigating.

All four were contacted by Reuters. Louis Dreyfus Commodities, the only one to respond, said it set prices in line with the international market and had tripled rates when Florida hurricanes in 2006 caused prices to spike.

Orange prices have been on a steady downward slide since September when the credit crisis worsened and even after minor frost damage in No. 2 world orange producer Florida and the threat of more cold weather there.

Data from the now defunct Abecitrus exporters' association around the middle of the decade estimated the total area planted with orange would fall 15 percent from 2000-2010 but intensified production meant output would fall just 5 percent.

With a host of diseases and pests preying on orange plants and fruit, the allure of cane for growers is easy to comprehend. Two potentially devastating maladies -- citrus sudden death and greening -- arrived during this decade alone.

Researchers are scrambling for cures, but the only solution in the meantime is to pull out infected trees. Industry sources said some orange production was being shifted further south to cooler areas in the state where greening cannot not flourish.

Cane mills are luring growers jaded by orange farming, taking care of the planting, harvesting and processing their cane in exchange for pre-determined share.

"It's up to you to spray weed killer and insecticide," said Joao Benedito Rossetti who switched his 150 hectare orange farm to cane in 2000 and says he hasn't looked back since.

Cane mills have mushroomed in the last few years as cars powered by cane-derived ethanol and popular in the 1970s and 1980s, were relaunched with much-improved technology in 2005.

But the switch to cane has cost jobs in these rural lands.

"(Cane) almost doesn't need the farmer to be there as the mill does most of the work," said Flavio Vegas from the Associtrus producers' association.