Studies on endophytic fungi associated with medicinally important aromatic plant Artemisia nilagirica (C.B. Clarke) Pamp. and their antagonistic activity against Phytophthora infestans

Antagonistic activity of endophytic fungi associated with medicinally important aromatic plant Artemisia nilagirica was studied against the pathogen Phytophthora infestans that causes late blight of potato. The study has a dual purpose, firstly identification of endophytic fungi isolated from Artemisia nilagirica; secondly, to evaluate their antagonism against Phytophthora infestans using the dual culture method. Altogether 23 fungal endophytes were isolated from root, stem and leaf of which 14 fungal endophytes were isolated from roots, 10 from stem and 6 from leaf. Among the isolates, 4 fungal species, namely Trichoderma viride, Penicillium atrovenetum, Aspergillus fumigatus and Cladosporium cladosporioides were selected to study the antagonistic effect against Phytophthora infestans. T. viride was found to have the highest percentage of inhibition of 67.0% followed by A. fumigates (59.6%), P. atrovenetum (56.7%) and C. cladosporioides (33.0%). Among the test organisms, a zone of inhibition was produced only by T. viride and P. atrovenetum. T. viride showed the maximum inhibition zone of 1cm against P. infestans while that of P. atrovenetum was 0.4cm. This study shows that out of the four test organisms, Trichoderma viride may be recommended as a good source of biocontrol agent against P. infestans the causal organism of potato late blight.