Abstract
Background: The Spodoptera frugiperda, commonly known as the fall armyworm (FAW), is a significant pest impacting agricultural productivity worldwide. Originating from tropical and subtropical regions, FAW has shown a high capacity for migration and destruction across a wide variety of crops. Integrated Pest Management (IPM) strategies offer sustainable approaches to managing pest populations, minimizing environmental impact, and reducing reliance on chemical insecticides.
Objective: This study aimed to evaluate the efficacy of combining biological control agents, specifically Heterorhabditis bacteriophora (Hb) and Beauveria bassiana (Bb), with the chemical insecticide chlorantraniliprole (Ch) against third and fifth instar larvae of S. frugiperda. The study sought to determine the potential synergistic effects of these combinations on larval mortality and developmental disruption.
Methods: The research encompassed laboratory bioassays, greenhouse, and field trials to assess the impact of the biocontrol agents and chlorantraniliprole, both individually and in combination, on FAW larval mortality and development. Larval populations of S. frugiperda were collected and reared under controlled conditions. Treatments applied included Hb, Bb, Ch, Hb+Bb, Hb+Ch, Bb+Ch, and Hb+Bb+Ch. Mortality rates were recorded at 3, 5, and 7 days post-treatment, while developmental parameters were assessed through pupation rates, adult emergence, and egg eclosion percentages.
Results: The combined application of Hb, Bb, and Ch significantly increased mortality rates in both the third and fifth instar larvae compared to individual treatments, with the highest mortality observed in the Hb+Bb+Ch group (100% by day 7). Developmental disruptions were also noted, including reduced pupation rates, adult emergence, and egg eclosion, particularly in treatments involving the combined use of biocontrol agents and chlorantraniliprole. Statistical analysis confirmed the significance of these findings (P<0.01).
Conclusion: The integration of Hb, Bb, and Ch presents a viable IPM strategy for effectively managing S. frugiperda populations. This combination not only enhances larval mortality but also disrupts developmental stages, offering a potential reduction in FAW infestation levels and associated crop damages. These results underscore the importance of adopting sustainable pest management practices that leverage synergistic effects between biological and chemical agents.
