Recent occurrence of fusarium oxysporum f. sp. cubense tropical race 4 in asia
Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is an important disease of banana in almost all banana-producing countries of the world. The recent occurrence of a highly virulent form of Foc in Asia, known as 'tropical race 4' (TR4), presents an imminent threat to the region's Cavendish-based banana industries. Foc-TR4 has caused severe damage to the Cavendish banana industry of Taiwan since 1967, destroyed new plantations of Cavendish banana in Indonesia and Malaysia since the early 1990s and caused field epidemics in the Northern Territory of Australia between 1997 and 1999. In 2004, severe Foc infection in banana plantations in Guangdong province, South China, heightened the TR4 threat. All outbreaks are associated with the vegetative compatibility group (VCG) complex 1213/16. Historical field observations of Foc in Cavendish banana cultivars in the Philippines since 1970 are described. More than 30,000 individual reports of infection were officially recorded in the Philippines from 1974 to 1991. These infections were tested and identified as VCG 0122, 0123 and 0126, which are believed to be less virulent than the VCG 01213/16 complex. In September 2006, 30 infected plant samples were collected from highland and lowland Cavendish banana farms in Davao. These samples confirmed that the recent outbreaks of Fusarium wilt in Cavendish in the Philippines were caused by the VCG 01213/16 complex. The Philippine government, private banana companies and Bioversity International are collaborating to manage the disease and to try to contain further spread of Foc-TR4.