Fusarium Wilt of Bananas in Jamaica: I. Some Observations on the Epidemiology of the Disease

The banana wilt pathogen Fusarium oxysporum f. cubense can bedetected in soil by a suitable host test. It often enters thehost through living rootlets, from which it passes into thevascular strand of the main root and thence into the rhizome;apparently infection does not occur through dead roots. The spread of wilt through plantations was studied by takingrecords at 2-monthly intervals: new cases arise both spontaneouslyand in association with pre-existing ones. Flooding is probablyimportant in local dispersal of the pathogen, as it is in long-rangedispersal. The relative importance of some other modes of dispersalis discussed. The soil population of F. oxysporum f. cubense increases considerablywhen wilted bananas collapse and declines shortly after theirremoval. If the site is replanted with a banana variety resistantto wilt the pathogen can thereafter often be detected in thesoil; in the absence of bananas, however, it cannot be detectedby any test after about 10 years, although its continued survivalis well established by many field observations on the incidenceof banana wilt. Little is known about its mode of survival insoil.