Evidence for the variation in susceptibility of bananas to wound anthracnose due to Colletotrichum musae and the influence of edaphic conditions

Wound anthracnose is a post-harvest disease which develops during storage a nd ripening of bananas. In the French West Indies, it mainly occurs on frui ts coming from plantations situated on soils at low-altitude, during the se cond half of the year. It is caused by a pathogenic fungus, Colletotrichum musae. A diagnostic survey was carried out on 106 plots representative of a ll the soil/climatic conditions and techniques in Guadeloupe in order to as sess the variability of fruit susceptibility to wound anthracnose. Secondly , the effect of mineral nutrition on this susceptibility was analysed for t he soil/climatic zone where the anthracnose problems are most serious. For this purpose, 54 plots on halloysitic and ferrallitic soils were chosen by including in the selection plots from all cultural situations. This study h as brought to light a wide variation in the susceptibility of bananas to Co lletotrichum musae. Fruits from high-altitude plantations are the least sus ceptible. On low-altitude soils, where the most variability is observed, a relationship was found between the Mn content of fruit and susceptibility t o anthracnose; the plants producing the most susceptible fruit had high fol iar Mn concentrations and low Ca concentrations, and had grown on rather ac id soils. Hypotheses for the physiological mechanisms involved in the sensi tisation of the fruit are discussed. (C) 2000 Elsevier Science B.V. All rig hts reserved.