Mortality and behavior of Neopamera bilobata (Hemiptera: Rhyparochromidae) subjected to an insecticide based on Sophora flavescens

Aiming at the production of a safe food and new alternatives to chemical pest control, this study investigated the mortality of adults of the strawberry seed bug, Neopamera bilobata (Hemiptera: Rhyparochromidae), subjected to different products, most of which have low toxicity and low environmental impact. The insects were collected in cultivated areas of Fazenda Escola farm, at the State University of Londrina. A stock culture was established in the Entomology Laboratory (T: 25 +/- 1 degrees C; 12-h photophase) and maintained on sunflower seeds and distilled water for the development of bioassays and experiment in a greenhouse. The insects were preliminarily subjected to the following treatments: water; a formulation with orange peel essential oil (1 mL L-1); a product based on Sophora flavescens (3 mL L-1); a formulation with orange peel essential oil (1 mL L-1) + S. flavescens (3 mL L-1); S. flavescens (3 mL L-1) + neutral detergent (1 mL L-1); silicone adjuvant (1 mL L-1); sucrose ester (1 mL L-1); and thiamethoxam (0.1 g L-1) as a positive control. Due to the efficiency of S. flavescens, with mortality greater than 90%, different concentrations (1, 2, 3, 4, and 5 mL L-1) were used on the adults. Higher doses of S. flavescens led to lower survival rates. After the dose of 4 mL L-1 was determined, another step was carried out in a greenhouse, using 18 pots with a capacity of 4 L of substrate containing plants of cultivar Albion surrounded by a voile fabric cage. Ten adult bugs were added to each pot; nine pots were sprayed with the S. flavescens-based product and the other nine only with distilled water. Sophora flavescens reduced the survival rate of N. bilobata in the laboratory and in the greenhouse. In conclusion, the S. flavescens-based product has the potential to control the bug N. bilobata at the tested rates, thus warranting further studies.