Interactions between Fusarium oxysporum and Meloidogyne arenaria as root pathogens of subterranean clover affected by soil sterilisation and inoculum substrate

摘要

Abstract Pot experiments were conducted to examine the effects, on the root health and growth of subterranean clover, of Fusarium oxysporum and Meloidogyne arenaria applied singly or in combination. The effects of the sterilised ryegrass seed substrate used for the growth of F. oxysporum, and of live and dead inoculum of this fungus were also investigated. In autoclaved soil, F. oxysporum was a virulent pathogen, causing severe root rot and seriously affecting plant growth. No nematode galls were formed in this soil when F. oxysporum and M. arenaria were inoculated together. But in pasteurised soil, although the fungus was the main cause of the root necrosis observed, it was only a weak or non-pathogen, and had little or no effect on M. arenaria root infection. In pasteurised soil, in addition to the fungus and nematode, the sterilised ryegrass seed, either colonised with the fungus or uncolonised, was also a contributing factor to the reduction in plant growth. The effects by these factors were independe...