Susceptibility of Red Flour Beetle Tribolium Castaneum (Herbst) (Coleoptera: Tenebrionide) Populations to Newly Synthesized Insecticides

Abstract

This study investigates the insecticidal toxicity of a newly synthesized, eco-friendly inert liquid insecticide against adults of the rust flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), a major pest of stored agricultural products. Bioassays were conducted across four constant temperatures (15°C, 20°C, 25°C, and 30°C) and three exposure periods (24, 48, and 72 hours) using various concentrations ranging from 50ppm to 5600ppm.The results demonstrated that insect mortality was highly dependent on temperature, dosage, and exposure duration. At the lowest tested temperature of 15°C, mortality remained relatively low, ranging from a minimum of 4% (3200ppm at 24H) to a maximum of 53.33% (50ppm at 72H). Efficacy improved significantly as temperatures increased, with the insecticide achieving its absolute maximum mortality rate of 90.67% at 30°C after 72 hours of exposure at a 200ppm dose. In contrast, the lowest overall efficacy was noted at 25°C after 48 hours, yielding only 2.10% mortality at a 50ppm dose. Generally, longer exposure periods substantially increased the mortality rate across most tested temperatures, highlighting the cumulative toxic effect of the formulation over time. These findings suggest that the newly synthesized eco-friendly liquid insecticide holds strong potential as an effective alternative agent for controlling T. castaneum populations, with optimum performance observed at higher temperatures and extended exposure intervals.