Biological control is the most current approach in sustainable agricultural system due to its potential of improving plant tolerance to pathogen and unfavourable environmental stresses. This research evaluates the biocontrol potentials of Glomus versiforme (wild and mutant) against Erysiphe flexuosa pathogen causing mildew disease in cowpea.wild strain of Glomus versiforme was subjected to random mutagenesis using UV irradiation for a regime of 4, 8 and 12 minutes , after which they were evaluated for their respective biocntrol activity (wild and mutant) against Erysiphe flexuosa in a dual culture assay and in the green house, Disease severity of various Glomus versiforme treatments were accessed after 7 weeks of green house plantation. The isolated mutants of Glomus versiforme was able to inhibit radial mycelia growth of the pathogen. The antagonistic activity follows the order Gv8>Gv4>Gvw>Gv12. Green house observation after 7 weeks shows that Gv8 also has the best agronomic parameters taking note of the plant height, number of leaves, fresh and dry weight of roots and shoots as compared to other mutant versions. The agronomic features with respect to Glomus versiforme treatments follows the order Gv8>Gv4>Gvw>Gv12>control>E.f. Gv8 shows the highest healthiness and lowest disease incidence.The disease incidence follows the order E.f>GV12>GVw>GV4>GV8.

Keywords: mutagenesis,biocontrol, Glomus versiforme,,Arbuscular myccorhizal fungi,radial mycelia,Erysiphe flexuosa