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 and ripening of bananas. In the French West Indies, it mainly occurs on fruits coming from plantations situated on soils at low-altitude, during the second half of the year. It is caused by a pathogenic fungus, Colletotrichum musae . A diagnostic survey was carried out on 106 plots representative of all the soil/climatic conditions and techniques in Guadeloupe in order to assess the variability of fruit susceptibility to wound anthracnose. Secondly, the effect of mineral nutrition on this susceptibility was analysed for the 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 has brought to light a wide variation in the susceptibility of bananas to Colletotrichum musae . Fruits from high-altitude plantations are the least susceptible. On low-altitude soils, where the most variability is observed, a relationship was found between the Mn content of fruit and susceptibility to anthracnose; the plants producing the most susceptible fruit had high foliar Mn concentrations and low Ca concentrations, and had grown on rather acid soils. Hypotheses for the physiological mechanisms involved in the sensitisation of the fruit are discussed.