Standardization of Antagonism Index Based Screening Technique for Determination of Biocontrol Potentiality of Trichoderma Species

摘要

Isolates of Trichoderma species express various levels of hyper-parasitism, competitive antibiosis and lysis of pathogens. Therefore, it is difficult to select the best isolates for use as biocontrolagets. Antagonism index based screening procedure was developed for selecting efficient Trichoderma isolates against four wide spread soil borne pathogens viz, Rhizoctonia solani, Sclerotium rolfsii, Fusarium solani and Macrophomina phaseolina. Antagonism index of the individual Trichoderma isolates against the pathogens was enumerated by quantitative and qualitative evaluation of different biocontrol attributes like, hyperparasitism, competitive saprophytic ability, secondary metabolite production ability, volatile activity, colonization behaviour, speed of overgrowth, lyitc enzyme production ability and plant growth promoting ability. Trichoderma isolates varied in their potentiality and several mechanisms seem to be responsible for their antagonistic property against a particular pathogen. Two Trichoderma isolates UBT18 and UBT8 have been identified as most effective against all the pathogens tested.