A SURVEY OF INSECTICIDES RESISTANCE IN POPULATIONS OF Tibraca limbativentris Stal. (HEMIPTERA: PENTATOMIDAE) AN INSECT-PEST OF FLOODED RICE IN BRAZIL

Abstract

The resistance of rice stalk stink bug, Tibraca limbativentris Stal 1860 (Hemiptera: Pentatomidae) to five insecticides was investigated in the present study. The tested insecticides were bifenthrin, carbosulfan, etophenprox, λ-cyhalothrin, and thiametoxam.  The five field-collected populations of rice stalk stink bugs from Luis Alves-GO, Flores de Goiás-GO, Formoso do Araguaia-TO, Lagoa da Confusão-TO and Itajaí-SC were investigated in relation the insecticide resistance occurrence. A further Santo Antônio de Goiás population, from natural environment was used as standard-population of susceptibility. Insects of these populations were submitted to discriminating concentrations (LC₉₅s) with objective to determine the frequences of individuals resistants. The insects population from Formoso do Araguaia were the most resistant to all tested insecticides.  The mortality values observed in this population were 76%, 86%, 72%, 80%, and 80% for carbosulfan, bifenthrin, etofenprox, λ-cyhalothrin, and thiamethoxam, respectively. The frequencies of resistant individuals ranged from 9% a 23% and were classified as moderate. The more expressive values of the resistance rate (RR) were found to the insecticide thiamethoxan 17-fold in the population of Formoso do Araguaia and 12-fold to the Luís Alves population. This first findings about insecticide resistance in T. limbativentris shows the seriousness of the problem in the region and suggests the possible occurrence  of cross-selection in this species, confering insecticide resistance to one or more products of different groups. These results are usefuls as information to integrated pest management (IPM) in the regions producers of flooded rice in Brazil, as technical guidance to rice farmers and open news perspectives of investigation in this research area.