IDENTIFICATION AND UTILIZATION OF Trichoderma spp. STORED AND NATIVE IN Sclerotinia sclerotiorum BIOCONTROL

ABSTRACT: The fungus Sclerotinia sclerotiorum, handles significant losses in lettuce production. Being a soil borne fungus, its management is difficult, and an alternative is the use of biological control using species of the Trichoderma genus. Thus, the objectives of this study were to identify native species of Trichoderma spp. presents in the soil with (CP) and without white mold (SP), evaluate the growth rate and in vitro antagonism of Trichoderma spp. against S. sclerotiorum and to verify the biocontrol potential of Trichoderma spp. microbiolized lettuce seeds, growing in substrate infested with S. sclerotiorum. Trichoderma spp. isolates were obtained from areas with and without history of white mold or stored in water. Mycelial growth rate and sporulation of the Trichoderma spp. isolates and control of Trichoderma spp. versus S. sclerotiorum in the in vitro essays. For thein vivo essay, lettuce seeds were microbiolized with Trichoderma spp. and the substrate was infested with S. sclerotiorum. The native isolates of Trichoderma identified belong to T. koningiopsis and T. asperellum species. The CP isolates had higher mycelial growth rates when compared to the SP isolates and stored while the stored isolates showed better responses in confrontation. The application of Trichoderma spp. promoted higher seedlings quality compared to control, as well as good seedlings development in the presence of the pathogen.