In the 1990s witches' broom disease (WBD), believed to have been introduced by humans, ripped its way through the main Brazilian cocoa region of Bahia, leaving 200,000 without work and decimating cacao supplies. As a result, in 10 years Brazil has gone from being the world's second-largest exporter of cocoa beans to a net importer.
Research programmes funded by the Brazilian government, including an attempt to sequence the genes of the pathogen, are aiming to shed light on this notoriously difficult disease that is proving extremely tricky to solve. But according to Dr. Gareth Griffith, a plant pathologist at the University of Wales, a risk assessment should be carried out as soon as possible.
"I feel that this has been disregarded as a small risk, but we need to learn from past mistakes. Improved travel links and world trade could allow fungal infections to spread to uninfected regions such as Ghana and the Ivory Coast," the scientist told FoodNavigator.com.
Griffith, who says that plant pathologists are sometimes the 'harbingers of doom', is calling for immediate research to quantify the risk of WBD spreading to West Africa, an assessment that could be quickly carried out with immediate benefits. "We need to identify potential risks and eliminate them straightaway," he added.
West Africa now accounts for 70 per cent of the world's output of cocoa beans. War and disease have marked volatile prices for cocoa in the past three years, peaking at 17 year highs in 2002 when the Ivory Coast in West Africa - source of two fifths of the world cocoa crop - endured civil war. Damage by WBD to these crops would send the prices soaring for chocolate production as global supplies plummeted.
But the chocolate industry claims that risk assessment is already underway.
Tony Lass from Cadbury emphasised that WBD is not a new problem - it is believed to have hit Latin America in about 1918 - and that the industry was investigating the risk. "WBD is extremely difficult to research and to resolve," he commented to FoodNavigator.com. "The chocolate industry and others are undergoing risk assessment of the disease," he added.
"We're trying to work with chocolate makers to get to the bottom of risk. We have it in hand and are sorting it out," a scientist who works for the chocolate industry said to FoodNavigator.com.
Witches' broom has spread in South America beyond Brazil to Peru, Ecuador, Venezuela, Colombia, Panama and Trinidad and Tobago. The disease is so named because the growing parts of the cacao tree become swollen and branched, giving the appearance of a witch's broom. It is caused by the pathogen Crinipellis perniciosa, and despite a century of research, no truly effective control strategy has been devised.
World production for cocoa reached 3.1 million tonnes in 2002-2003, according to recent figures from the London-based International Cocoa Organisation, marking a 8 per cent rise on the year before. But the price is intimately linked to political, climatic and disease-associated problems in the leading producer countries - the Ivory Coast, Ghana and Indonesia.
Circumstances clearly demonstrated when fears of more supply problems during civil war in the Ivory Coast in 2002 sent cocoa prices skyrocketing from £43 to £1,636 a tonne - a near 17-year high - on London's futures market.