Effectiveness of blue and green LED light against second-stage larvae of Meloidogyne javanica

The root-knot nematode Meloidogyne javanica is a globally significant agricultural pathogen, yet its management remains constrained by the ecological risks of chemical nematicides. This study investigated the wavelength-dependent phototoxicity of LED irradiation against second-stage juveniles (J۲s) under controlled laboratory conditions (۲۵±۰.۵°C, n=۴ replicates). J۲s (۲۰۰ per replicate) were exposed to monochromatic blue (۴۳۰-۴۶۰ nm), green (۴۹۵-۵۷۰ nm), yellow (۵۶۵-۵۹۰ nm), red (۶۰۰-۶۵۰ nm), or broadband white light (۳۶۰-۷۶۰ nm; reference) for ۱ to ۴ hours. Dose-dependent mortality increased across all wavelengths. Blue light induced ۲۰%, ۲۵%, ۲۷%, and ۱۰۰% mortality, while green light elicited ۷%, ۸%, ۲۰%, and ۱۰۰% mortality at ۱, ۲, ۳, and ۴ hours, respectively. Yellow and red light showed attenuated efficacy (reaching ۲۰% and ۶۰% mortality at ۴h, respectively). Atomic force microscopy (AFM) revealed cuticular ultrastructural aberrations in irradiated J۲s, including nanopore formation (۵۰-۲۰۰ nm diameter) and exoskeletal disintegration, which are hypothesized to result from photothermal and oxidative stress mechanisms. These findings demonstrate that blue and green spectra achieve comparable and complete lethality after ۴ hours of exposure, positioning photonic interventions as a promising, eco-conscious alternative for nematode biocontrol. Further research is needed to confirm the underlying oxidative stress pathways and assess field applicability

کلیدواژه ها:

Meloidogyne Javanica ، LED ، Destructive ، Mortality ، Wavelength