In this research, the efficacy of plant extract from Datura stramonium L. (Solanaceae) was tested against the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), for its toxic and antifeedant activity. The dried and powdered plant was extracted with 150 mL of absolute ethanol (99%, Merck) using a rotary evaporator extractor at 45 °C. Experiments were designed to measure the nutritional indices, such as relative growth rate (RGR), relative consumption rate (RCR), efficiency of conversion of ingested food (ECI), and feeding deterrence index (FDI). Treatments were evaluated by flour disk bioassay in the dark at 27 ± 1 °C and 60 ± 5% RH. Aliquots of 10 µL of acetone (control) or acetone extract (947-3007 mg L-1) were spread evenly on the flour disks. The solvent was allowed to evaporate, and then 10 adult insects were introduced into each treatment. After 72 h, nutritional indices were calculated. On the basis of the designed experiments, the calculated lethal concentrations of LC50 and LC90 of D. stramonium were 3936 and 15373 mg L-1, respectively. Results indicated that nutritional indices varied significantly as plant extract concentrations increased. As the concentration of D. stramonium increased, RGR, RCR, and ECI indices were reduced, and the most significant effect was observed at 3007 mg L-1. On the other hand, the FDI index increased with increasing extract doses and, as a result, insect food consumption was reduced. The results of data analysis showed that there is a significant difference between the plant and different concentrations in the feeding deterrence index of T. castaneum.

In this research, the efficacy of plant extract from Datura stramonium L. (Solanaceae) was tested against the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), for its toxic and antifeedant activity. The dried and powdered plant was extracted with 150 mL of absolute ethanol (99%, Merck) using a rotary evaporator extractor at 45 °C. Experiments were designed to measure the nutritional indices, such as relative growth rate (RGR), relative consumption rate (RCR), efficiency of conversion of ingested food (ECI), and feeding deterrence index (FDI). Treatments were evaluated by flour disk bioassay in the dark at 27 ± 1 °C and 60 ± 5% RH. Aliquots of 10 µL of acetone (control) or acetone extract (947-3007 mg L-1) were spread evenly on the flour disks. The solvent was allowed to evaporate, and then 10 adult insects were introduced into each treatment. After 72 h, nutritional indices were calculated. On the basis of the designed experiments, the calculated lethal concentrations of LC50 and LC90 of D. stramonium were 3936 and 15373 mg L-1, respectively. Results indicated that nutritional indices varied significantly as plant extract concentrations increased. As the concentration of D. stramonium increased, RGR, RCR, and ECI indices were reduced, and the most significant effect was observed at 3007 mg L-1. On the other hand, the FDI index increased with increasing extract doses and, as a result, insect food consumption was reduced. The results of data analysis showed that there is a significant difference between the plant and different concentrations in the feeding deterrence index of T. castaneum.