Evaluation of naturally occurring Pseudomonas spp. and a biopesticidebased on Trichoderma koningiopsis as potential biological control agentsof Olpidium virulentus in Fique

Abstract: We report the presence of Olpidium virulentus in roots of fique plants where Macanavirus disease has been detected. When fique plants obtained in vitro or lettuce seedlings used asmodel plant were inoculated with resting spores of O. virulentus, severe disease symptoms anddramatic fresh weight reduction were expressed. With the aim to select potential biologicalcontrol agents, sixteen indigenous isolates corresponding to Pseudomonas spp. and a biopesticidebased on T. koningiopsis were evaluated on lettuce planted in soil infested with O. virulentus. Sixisolates of Pseudomonas spp. and the biopesticide based on T. koningiopsis reduced of both thenumber of Olpidium sp. resting spores in roots, and the incidence and severity of the disease.These microorganisms also improved germination, promoted plant growth, presentedsolubilization phosphate activity and produced indol acetic acid (IAA).