Impacts of soil abiotic attributes on Fusarium wilt, focusing on bananas

Abstract

Production of many crops, including bananas, is threatened worldwide by the spread of pathogenic strains of Fusarium oxysporum, the causal agent of Fusarium wilt. Severity of the disease is related to soil biotic and abiotic attributes, which influence the plant, the pathogen and the other soil organisms. Across a variety of crops, soil temperature, redox potential, and extractable iron and manganese contents are generally positively correlated with disease severity, whereas pH, nitrate:ammonium ratio, organic matter content and extractable calcium, zinc, silicon, potassium, phosphorus and boron contents are negatively correlated, but less consensus exists for bananas. There are numerous incompletely understood interactions between soil abiotic attributes and disease severity, including those between pH- and redox-controlled micronutrient availability, buffering by organic matter and clay, and effects of nutrients on plant defence mechanisms. Though not all soil attributes can be managed, pH, organic matter content and availability of nutrients show promise for manipulation to reduce disease severity and mitigate risk.