Experimental cropping of Cavendish bananas without chemical control of black leaf streak disease

Black Leaf Streak Disease (BLSD) is the most important foliar disease affecting Caribbean and worldwide banana production for export. With growing concerns about environmental preservation, technical difficulties specific to local situations and increasing legislation constraints, alternatives to chemical control for BLSD are an important challenge. Agronomical practices allowing a slowdown of disease cycle and a reduction of its impact on fruit production (fruit weight and green life duration) should be part of an integrated strategy to reduce the use of pesticides. In collaboration with local farmer associations Adobanano and Banamiel, two hectares of Cavendish banana were grown, from June 2011 to June 2013, in the dry tropical climatic conditions of Dominican Republic. No chemical applications were realized during two years and 3 crop cycles. In spite of very low leaf surface at harvest time, green life of the fruit proved to be over 35 days, over the acceptable conservation duration for exported fruit. Impact on fruit weight was limited but needs to be confirmed by further experiments, in wet tropical climatic situations more conducive to disease development. A new trial was thus settled on a farm in June 2014 in Martinique and will allow exploring further disease impact on fruit yield and quality. This prototype is also applied since July 2014 as a commercial cropping system on a 10 ha field in Guadeloupe, in the driest part of the island, allowing a complementary evaluation in commercial farming conditions. Development and evaluation of pre-prototypes of multicrop systems are also explored through a trial in Dominican Republic since early 2014, with the association of banana and papaya. In such systems, the association of bananas with non-host species is supposed to affect disease cycle through a reduction of inoculum at plot scale, barriers to dispersion and an increase of inoculum interception. (Résumé d'auteur