Impact of femtosecond laser irradiation on survival and morphology of Tribolium castaneum

The use of chemical fumigants such as methyl bromide and phosphine to control red flour beetle has a negative impact on human health and environment. Moreover, effectiveness of these compounds has declined due to emergence of pesticides resistance. This emphasizes the need for safer and more sustainable alternatives. Physical control methods such as laser pulses represent powerful and environmentally safe option. Therefore, the present study investigated effectiveness of femtosecond laser light (FSL) on the survival of adult and larval stages of Tribolium castaneum . Femtosecond laser irradiation at 370 nm wavelength, 150 mW power, and 5 minutes exposure time induced 0% survivability of adult and larval stages of T. castaneum. While, using femtosecond laser light at 400 nm wavelength under the same parameters resulted in complete inhibition of survivability in adults, and larval survival decreased to 33.33%. Scanning electron microscopy (SEM) analysis of larvae revealed that 370 nm irradiation wavelength caused visible physical damage, including deformations in the dorsal cuticle, shrinkage of the abdominal surface and pygopods, loss of setae, and bulging. Similarly, the laser treatment of T. castaneum adults led to a reduction in elytra sensilla density and shrinkage of the ovipositor. In conclusion, femtosecond laser light showed pesticidal activity and induced physical damage against T. castaneum . Further studies are required to evaluate this effect under the field conditions. • Complete mortality of the insect achieved at 370 nm wavelength, 150 mW power in a 5-minute exposure. • The wave length 400 nm caused full adult mortality, but it resulted in only a 33.33% reduction in larval survival. • Scanning electron microscopy (SEM) of larvae showed that 370 nm irradiation caused dorsal cuticle deformation, abdominal shrinkage, setae loss, and bulging. • In adults, femtosecond laser light can damage insect reproductive structures.