Potential Effect of Magnetic Field on Spodoptera littoralis (Lepidoptera: Noctuidae): Development, Malform, Reproductivity and DNA Mutagenicity

Spodoptera littoralis (Boisduval, 1833) is one of the most destructive insect pests in Egypt and worldwide. This study was conducted to investigate the impact of exposure to a magnetic field (MF) of 180 milliTesla on the developmental phases of S. littoralis, as well as malform, reproductivity, and genomic DNA mutagenicity. The obtained results concluded that the exposure of S. littorelis to MF significantly affected the malformation and mortality rates in both larvae and pupae. The MF extended the duration of the pupal stage from approximately 0.8 to 5.9 days compared to the untreated pupae. The adult emergence percentages decreased to 68.0 and 74.0% upon exposure to a magnetic field for 60 and 40 min, respectively. The female fecundity decreased by increasing the exposure duration, yielding (7–10), (6–10), and (3–8) mass eggs per female upon exposure intervals of 20, 40, and 60 min, respectively. Meanwhile, the hatchability percentage diminished with prolonged exposure time, recording 77%, 60%, and 53% for MF exposure durations of 20, 40, and 60 min, respectively, compared to 91% hatchability in the control trial. The genetic characterization employing inter-simple sequence repeat (ISSR) markers disclosed genetic mutagenicity, exhibiting a similarity matrix range from 61.6% to 74.1% for larvae, 59.8% to 68.5% for adults, and 36.2% to 49% for pupae, indicating genetic alteration in treated insects. Hence, these findings highlight the implications and prospective application of a magnetic field of 180 milliTesla as a unique approach in integrated S. littoralis control frameworks.