F2 screen for resistance to Bacillus thuringiensis Vip3Aa51 protein in field populations of Spodoptera frugiperda (Lepidoptera: Noctuidae) from Texas, USA
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© 2019 Elsevier Ltd Fall armyworm, Spodoptera frugiperda, is a major target pest of pyramided Bt (Bacillus thuringiensis) corn and cotton in the U.S. In this study, we used a well-established F2 screening method to detect resistance alleles to Vip3Aa51 protein in field populations of S. frugiperda in Texas. In 2018, a total of 95 F2 two-parent families of S. frugiperda were established using single-pair mating of field individuals collected from two sorghum fields in two locations in Texas. For each F2 family, 128 neonates were screened on a diagnostic concentration of 3.0 μg/cm2 Vip3Aa51 protein using diet-overlay bioassays. The results showed that two out of 95 two-parent families possessed a major resistance allele against Vip3Aa51 protein. The estimated frequency of major resistance alleles against Vip3Aa51 in S. frugiperda in Texas was 0.0078 with a 95% CI of 0.0016–0.0188. The Vip3Aa51-resistant strain (TX-RR) derived from the F2 screening showed a high level of resistance to Vip3Aa51 protein, with a resistance ratio of >395.0-fold relative to a susceptible population (SS). Information generated from this study should be useful in studying mechanisms of Vip3Aa resistance in S. frugiperda, resistance monitoring, and resistance management of the Vip3Aa technology.
author list (cited authors)
Yang, F., Williams, J., Porter, P., Huang, F., & Kerns, D. L.