Agricultural pest management: Identification, characterisation, and stress tolerance of entomopathogenic nematodes

Abstract

Sustainable agriculture faces increasing challenges from insect pests as climate change and pesticide resistance reduce the efficacy of conventional pest control methods. This study evaluated the biocontrol potential of two new nematode strains, Oscheius sp. k KN-2024 isolate kv-2022 and Cruznema sp. NTM-2021. Using insect-baiting and modified White-trap techniques, the nematodes and their symbiotic bacteria were isolated, with DNA extraction performed using E.Z.N.A kits followed by sequencing and bioinformatic identification. Laboratory experiments assessed the efficacy and environmental tolerance of these potential entomopathogenic nematodes (EPNs) under varying temperature and desiccation conditions to enhance their application as eco-friendly alternatives to chemical pesticides. Cruznema sp. NTM-2021 demonstrated efficacy across a broad temperature range (5-30°C), exhibiting opportunistic pathogenic characteristics, while O. sp. k KN-2024 displayed true entomopathogenic behaviour with optimal efficacy at 25°C. At elevated temperatures (37°C), insect mortality occurred independently of nematode infection, indicating complex temperature-host-pathogen interactions. Desiccation trials revealed superior survival rates for both strains at higher relative humidity levels (75-85%), with O. sp. k KN-2024 demonstrating significantly greater desiccation tolerance than C. sp. NTM-2021. Peak survival was observed at 85% relative humidity over 24 hours. Four-way ANOVA confirmed statistically significant differences in performance across experimental conditions. These findings provide critical insights for optimising strain-specific EPN deployment in diverse agricultural settings, potentially reducing chemical pesticide dependence. By characterising the environmental tolerances of these novel nematode strains, this research advances the development of targeted, sustainable biological control strategies for integration into environmentally conscious pest management systems.