The expression profile of detoxifying enzyme of tomato leaf miner, Tuta absoluta Meyrik (Lepidoptera: Gelechiidae) to chlorpyrifos

Abstract

The tomato leafminer, Tuta absoluta (Meyrich) (Lepidoptera: Gelechiidae) is an important pest of tomato crops worldwide. The persistent use of organophosphate insecticide to control this pest has led to resistance. However, there is no report on the susceptibility and resistance mechanism of field population of Tuta absoluta (Meyrik) from Iran. Furthermore, the toxicity and impact of chlorpyrifos on metabolic enzymes in this pest remains unknown. The populations of T. absoluta from Rasht in Iran displayed LC30; 4332, LC50; 5010 and LC90; 7027 μg larva-1 to chlorpyrifos. The toxicity of chlorpyrifos could be synergized more bydiethyl maleate (DEM) and triphenylphosphate (TPP) whereas the synergistic effect of piperonylbutoxide (PBO) was not efficient as well as two other synergists. The synergistic effect ranged from 1.3 to 1.9-fold in 24 h and 1.2 to 1.5-fold in 48 h. The exposure with chlorpyrifos for 24 and 48 h significantly increased the activities of esterase and cytochrome P450-dependent monooxygenases, while there were no significant changes in glutathione-S-transferase. Field populations of T. absoluta from Iran displayed less susceptibility to chlorpyrifos and had a relatively high LC50 in compare to other previous studies. Esterases and cytochrome P450 monooxygenase might be involved in the metabolism, and hence resistance to, chlorpyrifos in this pest.

Keywords

• tomato leafminer
• chlorpyrifos
• Tuta absoluta
• synergistic effects
• resistance