Biochemical basis of conventional and novel mode of action insecticides resistance in field population of Diaphorina citri collected from Southern Punjab, Pakistan

Diaphorina citri Kuwayama is a phloem-feeding pest of citrus worldwide and vectors the putative causal agent of citrus greening, "Candidatus Liberibacter asiaticus" (CLas). Baseline toxicity and activities of esterases (EST), and glutathione-S-transferases (GST) sensitivity to bifenthrin, chlorpyrifos, thiamethoxam, acetamiprid, nitenpyram, chlorfenapyr and imidacloprid were established with field populations of D. citri. The highest calculated toxicity was observed in thiamethoxam treated D. citri with LC50 of 4.6 mu g/mL and minimum in chlorpyrifos and imidacloprid with LC50 values of 96.9 and 91.9 mu g/mL, respectively. The EST activity recorded in D. citri treated with different insecticides ranged from 11.8 to 52.1 mu mol/min/mg of protein, while GST activity ranged from 10.9 to 51.3 mu mol/min/mg of protein which subsequently linked with insecticide resistance. The present results provide a specific baseline to study levels of detoxifying enzymes against commonly used insecticides in D. citri that's indirectly correlated with level of resistance.