Insecticide toxicity and walking response of three pirate bug predators of the tomato leaf miner Tuta absoluta

1 The tomato leaf miner Tuta absoluta is a key pest of the tomato and is of global significance. Insecticide is the primary method for controlling this pest, requiring a search for compounds with a low toxicity to nontarget organisms. 2 We assessed the toxicity of eight insecticides to T. absoluta and its pirate bug predators Orius tristicolor, Amphiareus constrictus and Blaptostethus pallescens (Hemiptera: Heteroptera: Anthocoridae). We also assessed the effect of insecticide synergists on their toxicity to the predators, as well as their walking response to insecticide exposure. 3 All insecticides, with the exception of methamidophos, exhibited the minimum efficacy threshold required by the Brazilian legislation (80% efficacy) at concentrations lower than the registered label rates. Indoxacarb and chlorantraniliprole exhibited a lower toxicity to the pirate bug predators than to the tomato leaf miner. 4 The results obtained with the synergized insecticides suggest the involvement of cytochrome P450-dependent monooxygenases as the primary detoxification enzymes minimizing insecticide toxicity in the pirate bug predators. 5 The insecticides led to a reduction in predator walking activity, especially abamectin and indoxacarb, which significantly minimized predator exposure. 6 The results of the present study indicate that novel insecticides, especially chlorantraniliprole, are better suited to sustainable integrated management programmes of the tomato leaf miner.