S21 - Session O3 - Soil health research strategies for managing Fusarium wilt of banana in Brazil

Authors: Luiz Teixeira *, Edson Nomura, Erval Damatto Jr, Miguel Dita

Fusarium wilt of banana (FWB), caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc) is by far the major disease of banana in Brazil. Edaphic conditions may act as a driving factor to speed up or suppress FWB epidemics. Understanding physical, chemical, and biological interactions are key to managing suppressive or conducive soils to FWB. Two research approaches were conducted in parallel: a) identify potential biotic and abiotic soil predisposing factors associated with FWB and b) create contrasting environments by managing soil health factors to evaluate FWB intensity. In the first approach, soil chemical and physical attributes and plant nutritional status were evaluated in Foc-infested (Foc+) and healthy (Foc-) areas in three banana-producing regions in São Paulo, southeastern Brazil. Nineteen farms located in Vale do Ribeira (VR), São Bento do Sapucai (SBS) and Planalto Paulista (PP) were evaluated. In VR, FWB in Cavendish (AAA) and 'Prata' (Pomme, AAB) plantations was more intense in soils with lower pH, reduced base saturation, and low availability of Ca and Mn. In the PP and SBS regions, 'Prata' and 'Maçã' (Silk, AAB) plantations showed higher FWB intensity in more compacted soils with higher resistance to root penetration. We also noted that FWB can significantly affect the plants' nutritional status. Ca and K and their ratios with N were lower in plant leaves from Foc+ than from Foc- plots. Within the second approach, soil health-oriented management practices, such as the use of beneficial microorganisms, non-acidifying N sources, and compost application were tested in naturally Foc-infested field plots with "Prata" during three cropping cycles. Our data showed that the soil management practices were efficient to reduce FWB, enhance soil health and improve productivity. However, the effectiveness of these practices on reducing FWB decreased over time. Management practices and experimental approaches to better cope with FWB in Foc-infested soils are discussed.