Trichoderma characterization and potential of biological control against bean phytopathogens in vitro

Abstract

The occurrence of diseases is the main reason for reduction in common bean production in Brazil. Fusarium oxysporum f.sp. phaseoli and Sclerotinia sclerotiorum are the causative agents of important diseases of this crop. For the biological control to be successful for these and other diseases, the knowledge of the metabolites produced by the biocontrol agents such as Trichoderma spp. Is essential. From this point of view, this study aimed to characterize different isolates of Trichoderma spp. according to their metabolites production and verify the ability of these antagonistic isolates against the pathogens above mentioned. Twenty five isolates were tested, from three different species of Trichoderma. Their ability to produce hydrolytic enzymes, IAA and siderophores as well as their ability to inhibit the development of pathogens by the production of volatile metabolites and antagonism in paired culture were analyzed. All isolates produced chitinase, glucanases, proteases, IAA and siderophores. The production of volatile metabolites in vitro against F. oxysporum f.sp. phaseoli was effective with 24% of the isolates tested and 20% were able to inhibit the growth of S. sclerotiorum. In paired cultures, the reduction in growth for S. sclerotioum ranged from 67.5 to 100%, while for F. oxysporum f.sp. phaseoli reduction was from 29-50 %.