title: Assessment of resistance risk in Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) to chlorantraniliprole.
abstract: BACKGROUND
  Beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), is a major pest of numerous cultivated crops. Chlorantraniliprole, the first commercialised ryanodine receptor insecticide from the anthranilic diamide class, has exceptional insecticidal activity on a range of lepidopteran pests. The aim of this study was to assess the resistance of S. exigua to chlorantraniliprole in the laboratory.
  
  
  RESULTS
  A field-collected population of S. exigua was selected after repeated exposure to chlorantraniliprole to determine the risk of resistance evolution. After 22 generations of selection, there was a 12.0-fold increase in LC(50) . The realised heritability (h(2)) of resistance was estimated as 0.1082 by using threshold trait analysis. The projected rate of resistance evolution indicated that, if h(2) = 0.1082 and 70% of the population was killed at each generation, then a tenfold increase in LC(50) would be expected in 21.7 generations for chlorantraniliprole.
  
  
  CONCLUSIONS
  These results show that the risk of resistance development to chlorantraniliprole exists in S. exigua after continuous application.
authors: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors: Tiancai
authors: T
authors: Lai
authors: Jianya
authors: J
authors: Su