Baseline susceptibility and assessment of resistance risk to flubendiamide and chlorantraniliprole in Tuta absoluta (Lepidoptera: Gelechiidae) populations from Kuwait.
The tomato leafminer, Tuta absoluta (Meyrick), is one of the most destructive pests of tomato worldwide. T. absoluta has developed resistance to a wide range of insecticides in the field. This study aimed to assess the baseline toxicity of field populations of T. absoluta to flubendiamide and chlorantraniliprole, diamide insecticides recently registered to control the pest in Kuwait. Subsequently, the risk of resistance evolving as well as inheritance of resistance to the insecticides was investigated. The susceptibility variation among the populations tested was low (threefold for flubendiamide and fourfold chlorantraniliprole). The LC50 values for flubendiamide ranged from 0.04 to 0.11 mg L-1, whereas the LC50 values for chlorantraniliprole ranged from 0.29 to 1.13 mg L-1. After 34 generations of selection, 750- and 860-fold increases in resistance were recorded for flubendiamide and chlorantraniliprole, respectively. The realized heritability (h2) of resistance was estimated as 0.21 for flubendiamide and 0.29 for chlorantraniliprole, using threshold trait analysis. The values of the response quotient (Q) for resistance against flubendiamide and chlorantraniliprole were 0.11 and 0.13, respectively. We discussed our results with regard to the development of diamide resistance in T. absoluta, the potential spread of resistance, and strategies to mitigate the evolution of resistance.