Effect of nanoformulation of Nerium oleander (L.) aqueous leaves, based iron oxide nanoparticles for the control of Trogoderma granarium (Coleoptera: Dermestidae)

Abstract Trogoderma granarium, commonly known as the khapra beetle, poses a significant threat to global food security due to its destructive impact on stored grains. This study aimed to assess the effectiveness of iron oxide nanoparticles biosynthesized from Nerium oleander leaves extract as a biological nano-insecticide. This approach offers a safe and natural alternative to chemical pesticides for controlling insects. The evaluation was conducted at various temperatures (25°C, 35°C, and 40°C) using several concentrations of nano iron oxide: 1000, 2000, 3000, and 4000 ppm. The exposure periods were set at 24, 48, and 72 hours. A direct method was employed to determine the impact of these nanoparticles on the egg, larval, pupal, and adult stages of the insect. The research specifically evaluated the effectiveness of iron oxide nanoparticles in preventing egg hatching. The highest inhibition rate was recorded at a concentration of 4000 ppm, reaching 100% at temperatures of 35°C and 40°C after 72 h of exposure. Additionally, these nanoparticles exhibited significant insecticidal activity against larvae under all tested conditions. At temperatures of 25°C and 35°C, larval mortality reached 100% at a concentration of 4000 ppm after 72 h. At 40°C, however, 100% mortality was achieved at a concentration of 3000 ppm after the same exposure period. Mortality rates for pupae at 4000 ppm were observed to be 50%, 73.66%, and 100% after 72 h at temperatures of 25°C, 35°C, and 40°C, respectively. The highest adult mortality, which reached 100%, was noted at 4000 ppm after 24 h at 35°C. These findings highlight the potential of N. oleander as an eco-friendly biocontrol agent for managing T. granarium infestations. Key words: Iron Oxide Nanoparticles; Temperature; Larval mortality; Insecticidal activity