S21 - Session O3 - Impact of Fusarium wilt race 1 on Silk ‘Sotoumon’ banana cultivars in Benin: Opportunities for organic fertilizers

Authors: Anicet Dassou *, Sonia Déguénon, Elvire Sossa, Silvère Tovignan, René Tokannou, Gbèlidji Vodouhè, Claude-Gervais Assogba, Cathérine Akpodji, Delphine Bodjrènou, Martine Zandjanakou-Tachin, Aimé Bokonon-Ganta, Simplice Vodouhè

The dessert banana ( Musa sp.) cultivar "Sotoumon" (AAB genome, Silk subgroup), is highly valued and demanded in Benin. This cultivar is however, very susceptible to Fusarium oxysporum f. sp. cubense (Foc) race 1, a causal agent for Fusarium wilt of banana. The objectives of this study are i) to understand the distribution, damage and impact of Foc on income of small producers and ii) develop organic fertilization strategies to reduce the disease impact on susceptible cultivars. A survey was carried out in the major banana growing area located in the south of the country to determine Foc symptoms severity on Sotoumon plants and to assess yield losses. In a greenhouse the effect of Chromolaena odorata -based composts on the tolerance of the Sotoumon cultivars to Foc was determined. We recorded that in the banana growing area, 55% of the observed plants showed yellowing and wilting of the leaves, generally evolving from the oldest leaves to the youngest. The withered leaves broke off at the petiole and hung over the pseudostem. The damage caused by this disease has considerably reduced the income of banana farmers. In the greenhouse, Sotoumon plants were observed to be susceptible to Foc R1 though the onset of symptoms varied with the organic fertilizer rates. The diseased plants rate and the expression intensity of disease symptoms were lower in units heavily fertilized with Chromolaena odorata -based composts than in weakly and unfertilized units. Further studies are required to understand the role and mechanisms of organic fertilizers on the tolerance of Silk bananas to Foc R1.