Evaluating effective Trichoderma isolates for biocontrol of Rhizoctonia solani causing root rot of Vigna unguiculata

The highly diverse genus Trichoderma has provided many formulations that are alternatives to the chemical pesticides in agriculture. The present study was undertaken to investigate the biocontrol potential of eight Trichoderma species, T. atrobrunneum, T. guizhouense, T. paratroviride, T. pyramidale, T. rufobrunneum, T. simmonsii, T. thermophilum and T. viridulum, against the phytopathogenic fungus Rhizoctonia solani. Trichoderma isolates were first evaluated in vitro by dual culture tests for their antagonism, mycoparasitic ability and antifungal activity against R. solani. Their growth promoting potential was further assessed in relation to phosphate solubilization, indole acetic acid and siderophore production. Five of the isolates were selected and evaluated for their abilities to prompt plant growth and to control R. solani infecting Vigna unguiculata(cowpea) seedlings in vivo. Two most effective isolates, T. guizhouense 9185 and T. simmonsii 8702, significantly(P0.05) reduced the disease severity incidences(36.6 and 45.0%, respectively) and promoted plant growth, which have good prospects for application.