Suppressiveness or conduciveness to Fusarium wilt of bananas differs between key Australian soils

Abstract

Soils are known to differ in suppressiveness to soil-borne diseases, but the suppressiveness or otherwise to Fusarium wilt of Australian soils used to grow bananas is unknown. In this work we tested the relative suppressiveness of six key soil types. Banana (Musa (AAB group) ‘Pome’, cultivar ‘Lady Finger’) was grown in pots of the soils inoculated or not with Fusarium oxysporum f.sp. cubense (Foc) ‘Race 1’. Sixteen weeks after inoculation the plants were harvested and disease severity was assessed by measuring discoloration within the rhizome. In the inoculated pots, disease severity was greatest in the alluvial Liverpool and Virgil soils and least in the basaltic origin Tolga soil. No disease was detected in the non-inoculated pots. Soils with the lowest disease severity had the highest root mass, irrespective of inoculation, and the largest (negative) effect of inoculation on root dry mass. Disease severity in inoculated pots was negatively correlated with soil clay content and β-glucosidase activity. The results indicate that the risk of Fusarium wilt negatively impacting banana growth differs between soils of the main Australian banana-growing region.