BLOOD BACTERIAL WILT OF BANANA: HISTORY, FIELD BIOLOGY AND SOLUTION
Blood bacterial wilt was first noted on a small island in the Selayar group south of Sulawesi in Indonesia in 1905. The bacterium did not co-evolve with wild banana species in the region, nor with Heliconia. By 1920, the disease occurred and was studied in southern Sulawesi. It later spread over the whole island, but the mode of dissemination was not understood. The Dutch imposed a prohibition on inter-island banana transfer as a quarantine measure. However, the disease was found in Java in 1985 and later in Sumatra and Kalimantan, where it is now epidemic. The disease spreads rapidly because insects visiting the male inflorescences for nectar contact bacteria oozing from diseased male buds and transfer them to healthy buds. Bacteria enter exposed vessels where male flowers have just fallen from the peduncle cushion. They then spread proximally into the fruit and down the true stem to the rhizome. Only in the rhizome can the bacteria move into vessels leading to leaf sheaths and cause typical leaf yellowing symptoms. The disease is epidemic only in ABB/BBB cooking banana cultivars, like Pisang Kepok, which is common in villages throughout Indonesia. Although debudding was proposed in Central America in 1962 to halt the spread of the insect-disseminated SFR strain of the Moko bacterial wilt pathogen, which causes a similar disease in Bluggoe (ABB genome) to blood bacterial wilt, smallholder farmers did not do so in time to prevent infection, and the disease spread over vast areas. The discovery of a budless mutant of P. Kepok in Sulawesi in 1992 led to realisation that, in the area where the disease had been present for over 80 years, a budless mutant had occurred that was automatically propagated by a few villagers because it produced healthy bunches. Subsequent exploration in 2004-2006 revealed three different budless mutants, one of P. Kepok, one of a Cardaba type and one of a Bluggoe type. Many observations have confirmed that these clones are never diseased in the villages. P. Kepok has recently been declared a varietas unggul (outstanding cultivar) by decree of the Ministry of Agriculture of Indonesia. A project is being started to propagate budless P. Kepok in tissue culture on a large scale for distribution to farmers.
Buddenhagen, I. (2009). BLOOD BACTERIAL WILT OF BANANA: HISTORY, FIELD BIOLOGY AND SOLUTION. Acta Hortic. 828, 57-68
Indonesia, infection court, insect transmission, Moko bacterial wilt, bacterial strains, systemic infection, budless mutants