SMALL scale citrus producers in Brazil are becoming an endangered species as the world’s leading orange juice producer battles through its first decade living with the deadly Huanglonbing or greening disease.
The Brazilian definition of “small” is an enterprise with less than 300,000 trees.
The disease has skewed the structure of the industry in favour of big players since it was first discovered in 2004 with more than 30 million infected trees being destroyed.
It has been a big hit to the powerhouse production state Sao Paulo which boasts more than 200 million trees or 80 per cent of Brazilian citrus.
Leading citrus scientist Silvio Lopes said losses would continue to mount even though the major corporate producers were controlling the disease with aggressive intervention programs.
“On smaller farms the level of infection is still increasing year by year. The number of farmers is declining as individual orchards succumb to disease pressure,” Dr Lopes said.
“It will be difficult for a lot of producers to survive unless they work together on control programs. There is still a big role for education in the industry.”
Many farmers who were no longer economically viable growing citrus had shifted to other crops including sugarcane.
He said the disease had spread exponentially each year despite control efforts with the number of infected trees increasing from 0.6pc in 2008 to 7pc in 2012 when 64pc of all citrus blocks were affected.
Control measures focus on suppressing the population of citrus psyllid insects which spread the infection, removing the disease reservoir by destroying trees and ensuring new seedlings are disease free.
The industry faces an uphill battle despite a requirement for all growers to submit inspection and tree eradication reports every six months to the Coordinator of Agricultural Protection.
Australia is one of the few countries in the world still free of citrus greening disease where the threat will come from heavy infection pressure through South East Asia.
It has devastated the major citrus industry in Florida and spread from Mexico into California where the first psyllids were discovered in 2008 and the first disease outbreak was reported in a Los Angeles backyard last year.
Dr Lopes has travelled to Indonesia for a training and education program where he worked with an Australian specialist Professor Andrew Beattie from the University of Western Sydney.
“Indonesia has a lot of infected areas and the disease is spreading,” Dr Lopes, who is a plant pathologist with Fundecitrus at Araraquara, in the heart of the Brazilian industry, said.
Fundecitrus is an industry funded research and education institution with more than 80 staff, including 12 researchers who collaborate with specialist colleagues around the world.
It takes in about 20 students each year with courses focused on citrus pests and diseases.
With an annual budget of about US$4 million, Fundecitrus is running 155 research projects – 83 related to greening disease, 27 to citrus black spot and eight to citrus canker.
Dr Lopes said one focus of research was on trying to understand how the pathogen and insect vectors were affected by different climates.
“The disease is not spreading in hotter areas with the same speed that it does in mild climates,” he said.
Dr Lopes said the eventual answer to greening disease would be to introduce resistance through genetic manipulation.
“There is research going on, but we have not reached the stage where the technology is ready for field testing. Commercial production of resistant trees is not going to be a solution in the short term,” Dr Lopes said.
Big players control citrus greening disease
ONE of the big corporate players in Brazilian citrus, Cambuhy, has passed the peak of tree destruction with greening disease and is plotting future expansion.
Cambuhy has only been in citrus at Mateo in Sao Paulo State since 1992 and has charted rapid growth to 2.8 million trees and a modern factory which has a capacity to produce 40,000 tonnes of orange juice a year.
The 14,000 hectare estate has about 6300 hectares under citrus with other major crops including 800 hectares of rubber trees and 1000 hectares of sugarcane.
Cambuhy chief executive officer Alexandre Tachibana said the company had an active citrus renewal program of about 400 hectares and with closer planting technology tree numbers could climb to 3.2 million.
A total of about 140,000 trees infected with greening disease have been destroyed with the peak in 2010.
Last year about 50,000 trees were taken out and this year the total is expected to be about 21,000.
Cambuhy works actively with small neighbouring orchardists, helping them out with both disease surveillance and monitoring and spraying of psyllid insects.
The company focuses control measures intensively on its boundaries with psyllid spraying 24 times a year, much of it by air.
All new seedlings are treated with systemic insecticide until they are two years old.
Five years ago there were about 200 small orchardist neighbours and that number had now fallen to 77, Mr Tachibana said.
Cambuhy harvests oranges from May to February with the fruit collected into one-tonne bags which are emptied into field trucks and taken to a transfer station for loading out to the juice factory.
Production rates of up to 60 tonnes a hectare are being achieved and with high density plantings yields could top 80 tonnes.
“We’ve invested heavily in measures to control greening disease and our good neighbour policy is paying off with reduced rates of infection on our property,” Mr Tachibana said.