Every few years, it seems, a scare goes around threatening the end of the global commercial banana industry—and usually the focus of the scare-stories is Panama disease, caused by the fungus ‘Foc’ (short for Fusarium oxysporum f. sp. cubense).
The variety that made banana the ‘world’s favourite fruit’ was Gros Michel, but it was knocked out as a commercial crop in the 1950s and 1960s by Panama disease, specifically a form that we now call ‘Foc Race 1’. The banana that took its place was Cavendish, a variety found to be resistant to that form of Panama disease and subsequently distributed around the world. It currently dominates the global trade in bananas. But now the Cavendish banana has met its nemesis in the form of Tropical Race 4 of Panama disease—Foc-TR4. The new form of the disease has just about wiped out commercial Cavendish production in Malaysia and Indonesia (despite the best efforts of ACIAR’s previous Panama disease project in Indonesia), and this year there have been outbreaks, for the first time, in Africa and the Middle East.
The front line in ACIAR’s battle with Foc-TR4 has now shifted to the southern Philippines, where ACIAR has recently launched a new project. There, some of the key players who were involved in the Indonesian project—Bioversity International and Queensland’s Department of Agriculture, Fisheries and Forestry—have taken on board the lessons learned and are now trying to apply them to managing the disease, in collaboration with Filipino research organisations and commercial industry partners.
While the Indonesian project looked at specific antagonists to Foc, especially other fungi living in the soil that could compete with and control it, the Philippines project is focusing on encouraging farmers to grow groundcovers between the banana plants. Groundcovers can provide a favourable environment for a range of these antagonists to develop naturally. They also provide additional benefits, such as reducing soil erosion and surface water flow that can carry the fungus from plot to plot, as well as reducing the risk of farm workers carrying the disease in contaminated soil on their shoes.
In a recent visit to Davao, the hub of the Philippines’ banana industry, Queensland groundcover-advocate Tony Pattison engaged directly with some of the farmers to see what plant species might be acceptable within their production system. He also met with local researchers to see which species could be sourced locally and rapidly propagated. In addition the team discussed with the farmers how they liked the Foc-TR4-tolerant variants of Cavendish, selected in Taiwan and made available to other countries including the Philippines, through Bioversity International’s BAPNET.
The take-home message from our exploratory visit was that the banana industry is extremely competitive and, while producers are anxious to try our new combination of groundcovers and disease-tolerant varieties, the new technology will have to deliver high productivity quickly if it is going to save the local industry.
There are benefits to Australia too from this research. For example, Australian researchers and industry partners are evaluating and gaining experience in the use of groundcovers to manage Foc Race 1, which attacks Australia’s Lady Finger bananas. It will also serve as something of a ‘dress rehearsal’, in case Foc-TR4 should ever threaten the heart of Australia’s commercial banana industry—the Cavendish plantations in Queensland and northern New South Wales.
By Richard Markham, ACIAR Research Program Manager for Horticulture
ACIAR project HORT/2012/097—Integrated management of Fusarium wilt of bananas in the Philippines and Australia
ACIAR project HORT/2004/034—Diagnosis and management of wilt diseases of banana in Indonesia
ACIAR project HORT/2005/136—Mitigating the threat of banana Fusarium wilt: understanding the agroecological distribution of pathogenic forms and developing disease management strategies