Evaluation of potential bio-control agents on root-knot nematode Meloidogyne incognita and wilt causing fungus Fusarium oxysporum f.sp. conglutinans in vitro
Indigenous strains of Trichoderma viride (ITCC No. 6889), Pseudomonas fluorescens (ITCC No. B0034) and Purpureocillium lilacinum (ITCC No.6887) were isolated from undisturbed forest eco-system of Southern India. These three bio-mediators were evaluated for their antagonism towards root knot nematode, Meloidogyne incognita and Fusarium oxysporum f.sp. conglutinans in vitro. Cell free culture filtrate of these strains significantly inhibited the egg hatching and caused juvenile (J2) mortality of M. incognita at 25, 50, 75 and 100% concentrations. Maximum inhibition in egg hatching and juvenile mortality were recorded in P. lilacinum as 94.21 and 91.28%, respectively after 120 h. It was followed by T. viride and P. fluorescens which recorded 92.72 and 91.46% and 89.12 and 90.14% inhibition in egg hatching and juvenile mortality, respectively after 120 h. Antagonism of T. viride on F. oxysporum was recorded maximum on the 5th day as 45.82%. Similarly, the antagonism on the 5th day for both the bioagents of P. lilacinum and P. fluorescens were recorded as 45.26 and 44.19%, respectively.
Key words: Biocontrol agents, culture filtrate, Fusarium oxysporum, Meloidogyne incognita.