Efficacy of Bt Transgenic Sugar Beet Lines Expressing cry1Ab Gene Against Spodoptera littoralis Boisd. (Lepidoptera: Noctuidae)

The sugar beet, Beta vulgaris L., has some key pests in Iran that causes losses in crops. One of these pests is Egyptian leaf worm, Spodoptera littoralis (Boisd). In addition to southern regions of Iran especially in Khuzestan province, this pest is distributed throughout the countries around the Mediterranean region. One of the most effective controlling measures against this pest is planting Bt transgenic sugar beet, expressing an insecticidal-protein gene from Bacillus thuringiensis subsp. kurstaki (Berliner). Larval mortality, larval weight loss, and leaf weight loss as a damage index of this pest on 10 lines of transgenic and 2 non-transgenic sugar beet were studied. In each treatment, 40 larvae of the Egyptian leaf worm (10 larvae/replication) were fed on the leaves of the transgenic lines in glass petri dishes. Larval mortality, weight of the alive larvae, and weight loss of the leaves were recorded after 3 and 6 days. ANOVA results revealed that there were significant differences between the treatments at the 1% probability level considering all evaluated factors. Therefore, mean comparisons were carried out using Duncan's multiple range tests. Based on the results, all of the examined transgenic lines were more effective than non-transgenic line. In addition, the transgenic line S 37-3 was the most effective line among evaluated transgenic lines.