Toxic effects of some pesticides on Deraeocoris lutescens in the laboratory

The susceptibility of the predatory bug, Deraeocoris lutescens Schilling (Rhynchota Miridae), to some common pesticides was investigated in the laboratory. Seven pesticides (abamectin, fenpropathrin, imidacloprid, pirimicarb, spirodiclofen, thiacloprid and penconazole) were assayed for their effects on the predator. These pesticides were tested at a single rate of application corresponding to their maximum recommended label rate. The toxicity of these compounds to eggs, N sub(1) and N sub(5) nymphs and adults of D. lutescens by residual contact was investigated and mortality of the biotests was recorded 24, 48, 72 and 96 hours after treatment. The corrected mortalities of N sub(1) and N sub(5) nymphs and adults were evaluated by the IOBC toxicity rating scale for pesticides. Penconazole and spirodiclofen caused the least mortality on different life stages of the predatory bug. The highest mortality was occurred by fenpropathrin, imidacloprid and thiacloprid. The eggs mortality was highest after exposure to fenpropathrin. Spirodiclofen and penconazole caused the least mortality with 10.4% and 19.1%, respectively. The residue of fenpropathrin, imidacloprid and thiacloprid were harmful to N sub(1) and N sub(5) instars of the predator. In contrast, penconazole and spirodiclofen residues were harmless. Abamectin was slightly harmful to N sub(1) and N sub(5) instars. The residue of pirimicarb was moderately harmful to the N sub(1) instar and it was harmless to the N sub(5) instar and adults of the predator. Fenpropathrin was harmful to adult males and females. In contrast, abamectin, pirimicarb, spirodiclofen and penconazole were harmless to the adults.