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

Abstract

Abstract 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. 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. 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. 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. The insecticides led to a reduction in predator walking activity, especially abamectin and indoxacarb, which significantly minimized predator exposure. 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.