EFFECTS OF SONICATION DURATION AND CONCENTRATION OF NEEM-BASED ECO-ENZYMES ON Spodoptera litura MORTALITY

Abstract

Spodoptera litura is a major agricultural pest causing substantial crop losses. Neem-based eco-enzymes produced through organic fermentation contain bioactive compounds with potential insecticidal activity. This study investigated how sonication duration and eco-enzyme concentration affected S. litura mortality and estimated the Lethal Concentration (LC₅₀) and Lethal Time (LT₅₀). This study systematically evaluated combined sonication durations and concentrations of neem-based eco-enzyme formulations through topical and oral bioassays, enabling comparison of insecticidal performance across exposure routes. A completely randomized design comprised 12 treatments: 9 combinations of 3 sonication durations (3, 5, and 7 h) and 3 concentrations (3%, 5%, and 7%), a 20% non-sonicated eco-enzyme treatment, a control treatment, and a chemical insecticide treatment. Each treatment included 3 replications with 20 third-instar larvae per experimental unit. For each bioassay, we randomly selected 720 larvae from 800 eligible larvae. We recorded mortality at predetermined intervals over 7 days. Data were analyzed using analysis of variance, followed by Duncan’s Multiple Range Test at the 5% significance level. We estimated LC₅₀ and LT₅₀ using probit analysis. The 3-hour sonication treatment at 7% concentration produced the highest mortality, reaching 81.67% in the topical assay and 80.00% in the oral assay after 7 days. These findings identify a promising formulation and provide comparative evidence of its activity through two application routes. The estimated LC₅₀ and LT₅₀ were approximately 2% and 3 h, respectively. Further studies should characterize physicochemical properties and validate efficacy under field conditions.

Keywords

• Eco-Enzymes
• Mortality
• Nanoformulation
• Sonication
• S. litura