EVALUATION AS BIOLOGICAL CONTROL AGENTS AGAINST THE FALL ARMYWORM Spodoptera frugiperda (LEPIDOTERA: NOCTUIDAE) AND CHARACTERIZATION OF MEXICAN Bacillus thuringiensis STRAINS

Five Mexican strains of Bacillus thuringiensis with activity against the fall armyworm Spodoptera frugiperda were evaluated and characterized using bioassays, protein profiles, patterns of plasmid DNA and PCR. The bioassays showed that two of the five strains, LBIT-13 and LBIT-418, showed high toxicity towards S. frugiperda, with LC50 of 137.2 and 197.2ng.cm(-2), respectively, when compared with the standard HD-1 (CL50=142ng.cm(-2)). Also, LBIT-44, LBIT-383 and LBIT-428 strains showed lower levels of toxicity with LC50 of 338.2, 474.5 and 523.8ng.cm(-2), respectively. Protein profiles of the five strains showed two major proteins of 130 and 65kDa. In terms of plasmid patterns, the five strains showed significant differences in quantity and molecular weight of the plasmids. In three strains, LBIT-13, LBIT-44 and LBIT-383, possible cry genes were detected by PCR. At least two strains possess potential for use as biological control agents against the fall armyworm in Mexico.