Ecological studies of Trichoderma bio-inoculants in the soil ecosystem of Pinus radiata

Three isolates of different Trichoderma species were selected for this study. T. hamatum (LU592) and T. harzianum (LU686), were known to stimulate growth and improve establishment of P. radiata seedlings, and T. atroviride (LU132) had no stimulatory activity. The ability of these isolates to establish and survive in bulk soil, the rhizosphere, rhizoplane or endorhizosphere of P. radiata seedlings was determined. In addition, the effect of each isolate on P. radiata seedling development and growth was assessed and is currently being confirmed in a large scale commercial experiment. From the nursery experiment, the Trichoderma isolate which was the most effective at colonising all P. radiata root subsystems (LU592) was selected for more detailed ecological studies using genetically marked strains. Current experiments are focussed on the spatial dynamics of Trichoderma within the rhizosphere of P. radiata. The implication of the results in relation to the use of Trichoderma bio-inoculants in the nursery will be discussed