EVALUACIóN DE LA EFECTIVIDAD DE DOCE CEPAS DE Trichoderma asperellum Samuels SOBRE TRES FITOPATóGENOS EN CONDICIONES DE CAMPO

the incidence of plant diseases caused by fungal agents increases every year at worldwide scale making necessary the search and introduction of new control alternatives. trichoderma is a most widely applied microorganisms as an agent of biological control (bca), for its different mechanisms of action (l.e., competition for the substrate, antibiosis and/or mycoparasitism). the present work was aimed to evaluate the efficacy of twelve strains of trichoderma asperellum on three phytopathogens artificially inoculated under field conditions. the efficacy of t. asperellum was evaluated on bipolaris oryzae (breda de haan) shoemaker, curvularia lunata (wakker) boedijny and fusarium oxysporum f. sp. lycopersici (sacc.) w.c. snyder and h.n. hans. the number of colonies/gram of soil was calculated, as well as the efficacy of t. asperellum isolates using abbott`s formula, from the total number of colonies growing on the plate. eleven of the isolates of t. asperellum shower a technical efficiency over 80% on at least two of the pathogens. t.1 and t.90 stood out with a technical efficiency over 90% on the three pathogens. this effect was not evident for isolating t. 25, showed control only on c. lunata, since the assessment only took into account effective technique over 80%. these results show that the strain selection is an important element in the management and control of diseases.