Patogenicidad de Beauveria bassiana (Bals.) Vuillemin sobre estados inmaduros de mosquita blanca (Bemisia tabaci Genn.)

the pathogenicity of three indigenous (bb-cam, bb-c y bb-m) and one commercial (bea-sin) isolates of beauveria bassiana were evaluated on immature states of bemisia tabaci. the evaluation was carried out under laboratory conditions with temperature of 27 ± 3oc and relative humidity of 75 ± 8%, by the application of a conidial suspension containing 1 x 107 spores ？ ml_1 to eggs and first instar nymphs. the effect of b. bassiana was higher on nymphs than on eggs. no significant difference (p> 0.05) was observed on egg mortality caused by b. bassiana isolates. these isolates showed different degree of pathogenicity on nymph bioassay. the isolate bea-sin showed the highest (p < 0.05) effect (67.9% mortality). the rest of the isolates caused mortality from 42 to 50%. the medium lethal time (tl50) and the area under the curve of cumulative mortality (auccm) were calculated for the nymph bioassay. bea-sin showed the lowest tl50 and the highest auccm, with values of 3.6 days and 381.22 units, respectively. these results indicate that bea-sin showed more virulence than the indigenous isolates