Mellein, a dihydroisocoumarin with bioherbicidal activity from a new strain of Lasiodiplodia pseudotheobromae C1136

•Bioherbicidal activity, isolation and purification of the secondary metabolites produced by C1136 strain.•Structural elucidation of the active component.•Host range test and antimycotic activities of the active component.•The purified compound does not have any adverse effect on the germination, root length, shoot length of cowpea seedlings.