NON-PREFERENCE FOR OVIPOSITION AND NYMPHAL VIABILITY OF Bemisia tabaci BIOTYPE B (HEMIPTERA: ALEYRODIDAE) ON BT COTTON AND ON ITS NON-TRANSGENIC ISOLINE

The risk assessment of large-scale releases of genetically modified plants into the environment is important to minimize the hypothetical impacts on bio-ecology of non-target species. This study aimed 1) to discriminate the oviposition preference of Bemisia tabaci (Gennadius) biotype B among DeltaOpal (R) (conventional cotton cultivar) and Nu Opal Bollgard (R) (transgenic expressing Cry1Ac toxin) and 2) study the viability of the fly nymphs in both near-isogenic cotton cultivars. The experiment was conducted under greenhouse conditions, with a completely randomized design, with two treatments (cultivars) and I I repetitions. The whitefly eggs were quantified 24h in cage after infestation with reared adults, and the number of nymphs of the insect sampled every five days for 30 days after infestation (six evaluations). Data were subjected to analysis of variance (F test) and then means were compared by Student I test. There was no oviposition preference of B. tabaci on either cotton cultivar, indicating no differential attractiveness between genotypes. The transgenic cultivar does not affect numbers of whitefly nymphs when compared with its conventional genetic isoline.