Susceptibility of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) to Natural Products and Entomopathogenic Fungi

Abstract

Abstract Background: Synthetic insecticides have a direct adverse effect on the natural enemies and long-term residual effects causing serious environmental pollution as well. The public awareness for a clean environment increased the attention on developing alternative eco-friendly approaches. This study aimed to detect the effect of Beauveria bassiana, Metarhizium anisopliae, and natural products of plant-extract origin on the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) under laboratory conditions. Results: The drench-bioassay results showed that mortality of larvae by B. bassiana KACC40224 increased from 10% to 80% as the dose was increased from 10 × 105 to 10 × 109 conidia ml−1. However, mortality by M. anisopliae KACC40029 reached maximally 60% at the dose of 10 × 109 conidia ml−1. All natural-extract products tested against the insect pest were effective, except lavender oil, they caused mortality varied between 10% and 100%. Rosemary oil was found to be the most effective essential oil, showing 10% to 100% mortality indices at a concentration of 0.1 and 0.2% (v/v), respectively. S. frugiperda eggs tend to be more susceptible to entomopathogenic fungi rather than the larvae. The essential oils exhibited significant insecticidal properties against the larvae of S. frugiperda. Conclusion: This study could help in the development of potential biopesticides for the environment-friendly management of the fall armyworm S. frugiperda pest and emphasize the advantages of entomopathogenic fungi application.