Abstract
Fusarium oxysporum has a worldwide distribution and is responsible for severe vascular wilt or root rot. Currently, no effective curative treatments to control the fusarium wilt exist. Thus the study was undertaken to find out the antagonistic potential of Trichoderma harzianum and Trichoderma viride isolated from the soil of date palm field against F. oxysporum in vitro. All species of Trichoderma showed the appreciable inhibition of mycelial growth of the pathogen. Results of dual culture interaction test showed that TvDPs (66.3%) was best antagonist in inhibiting the growth of pathogen followed by TDPs (57.4%) and T1s (56.43%) respectively. Volatile metabolites produced by T. viride (TvDPs) exhibited highest growth inhibition (40.91%) followed by T1s (25.97%) and TDPs (7.57%) respectively. The culture filtrate of all antagonists incubated at 25 degrees C showed maximum reduction in radial growth of pathogen. The cell free culture filtrate of T. viride incubated at various temperatures inhibited the radial growth of F. oxysporum at varying degree. Whereas, culture filtrates of T. harzianum isolates incubated at 40 degrees C were unable to control the growth of the pathogen. TvPDs showed best sporulation and mycelial growth on SDA medium, whereas T1s and TDPs flourished well on both PDA and SDA media. On natural media agar (PDA + 1% date palm leaves) the antagonist TvPDs sporulated luxuriously. Present study clearly indicates an excellent antagonistic activity of T. viride (TvDPS) against F. oxysporum in vitro condition.