Addition of Trichoderma consortia to Chilean endemic flora compost teas strongly enhances in vitro and in vivo biocontrol of phytopathogenic fungi.

Abstract

To evaluate the in vitro and in vivo antifungal capability of diverse compost teas of endemic Chilean flora inoculated with a consortium of fungal strains of Trichoderma spp. (biocontrol agent) against three important phytopathogens: Botrytis cinerea, Fusarium oxysporum and Lasiodiplodia theobromae. Compost teas were obtained from endemic flora of Chile (Azara celastrina, Citronella mucronate, Cryptocarya alba, Peumus boldus and Quillaja saponaria). Eleven Trichoderma strains were isolated and antagonism tests were performed to develop fungal consortia with biocontrol properties. The biocontrol effect of compost teas inoculated with Trichoderma consortia was also analyzed. The results showed that the teas possess antifungal activity against B. cinerea and F. oxysporum and, to a lower degree against L. theobromae. In vitro tests showed that Trichoderma consortia improved the suppressive effect against B. cinerea (94%-97%), F. oxysporum (89%-92%) and L. theobromae (51%-73%). P. boldus tea showed the highest suppressive effect against the plant pathogen L. theobromae. In addition, the in vivo assay showed that tomato plants treated only with Trichoderma or compost tea, did not show differences in height with regard to control plants. However, when these two treatments were combined, the best performance in plant height and protection against pathogens was observed. This study indicates that the addition of a consortium of Trichoderma strains with intra- and interspecific incompatibilities, significantly improves the inhibitory effect of compost teas in in vitro tests against the plant pathogenic fungi, while in vivo, enhances tomato plant growth and reduce plant disease symptoms.