ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
M. Ragasruthi1, N. Balakrishnan1 , M. Murugan1, N. Swarnakumari2, S. Harish3, D. Jeya Sundara Sharmila4, G. Rajadurai5 and R. Raghu5
1Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
2Department of Plant Protection Studies, Horticultural College and Research Institute for Women, Tamil Nadu Agricultural University, Tiruchirappalli, Tamil Nadu, India.
3Department of Oil Seeds, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
4Centre for Agricultural Nano Technology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
5Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
Article Number: 10536 | © The Author(s). 2025
J Pure Appl Microbiol. 2025;19(4):3172-3185. https://doi.org/10.22207/JPAM.19.4.58
Received: 28 April 2025 | Accepted: 02 September 2025 | Published online: 08 December 2025
Issue online: December 2025
Abstract

Spodoptera frugiperda is one of the most destructive pests affecting economically important crops like maize and sorghum. Traditional management strategies rely highly on chemical insecticides, leading to environmental concerns and resistance development issues, necessitating alternative strategies for effective pest management. Biopesticides, particularly Bacillus thuringiensis (Bt)-based formulations, offer an environment friendly alternative due to their specificity and safety. However, the efficacy of the Bt often hindered by issues related to stability and application efficiency. This research focuses on development of formulation and evaluation of Bt-based water-soluble emulsion for the management of S. frugiperda. The Bt strain T414 containing cry and vip genes, was used to formulate a stable water-soluble emulsion. Mineral oil (light liquid paraffin) was chosen as a carrier oil, and Tween®80 and Span®80 were used as surfactant mixtures for enhanced miscibility, and stability. The final formulation, incorporating glycerol and trehalose as stabilizers, exhibited a droplet size of 177-187 nm and zeta potential of -28 mV, indicating good colloidal stability. The pH remained within an optimal range (6.92), and viscosity analysis confirmed shear-thinning behaviour, ensuring ease of application. Laboratory bioassay demonstrated that the emulsion formulation exhibited higher insecticidal activity, with a calculated LC50 of 0.006 µg/ml, compared to the spore-crystal mixture. This enhanced insecticidal efficacy suggests improved bioavailability of the active ingredients in the emulsion formulation. This study emphasizes the ability of Bt-based water-soluble emulsion formulation as environmentally safe and effective alternative for pest management, reducing dependence on chemical insecticides, subsequently promoting sustainable pest control.

Keywords

Bacillus thuringiensis, Spodoptera frugiperda, Emulsion Formulation, Bioassay, Pest Management

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© The Author(s) 2025. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.