Toxicity of Ocimum basilicum L. leaf extract against Spodoptera exigua Hübner (Lepidoptera: Noctuidae)

Abstract

The beet armyworm Spodoptera exigua Hübner (Lepidoptera: Noctuidae) is one of the most significant shallot pests worldwide, which affects agricultural production by approximately 100% in Indonesia. The growing awareness of sustainable agriculture encourages the search for natural alternatives to synthetic pesticides that promote resistance and contaminate the environment. Therefore, this study aims to evaluate the efficacy of basil (Ocimum basilicum L) leaf extract against the 2nd and 3rd instar larvae of S. exigua. The extracts were prepared using maceration and hydrodistillation and the pathogenicity was carried out against the 2nd and 3rd instar of S. exigua using three replicates with several doses of extract ranging from 0- 2.0%. The extracts were applied to the larvae using contact and topical methods. The results showed that maceration extraction yields a greater extract with different types compared to those of the hydrodistillation method. Maceration extract of basil leaves with the contact application method to 2nd instar showed better results than the topical application with the highest mortality rate of 75% (F=24.464; P< 0.001) and LC50 of 0.007%. This indicated that basil leaf extract with the contact application method has great potential to be developed as a botanical insecticide to control S. exigua in the field as part of Integrated Pest Management (IPM).