<![CDATA[Background: Continuous reliance on synthetic insecticides for controlling Helicoverpa armigera may lead to pest resistance, resurgence, and environmental residues. Neem (Azadirachta indica A. Juss.) leaf extract, which contains the bioactive compound azadirachtin, has potential as a more environmentally friendly botanical insecticide. Objective: This study aimed to determine the effective concentration of neem leaf extract against the mortality of H. armigera under laboratory conditions. Methods: The experiment was arranged in a Completely Randomized Design (CRD) with five concentrations of neem leaf extract (0, 25, 50, 75, and 100 g/L water) and four replications, resulting in 20 experimental units. Each experimental unit was infested with 10 third-instar H. armigera larvae. The observed variables included initial mortality time, lethal time 50 (LT₅₀), daily mortality, total mortality, and ambient temperature and humidity. Data were analyzed using analysis of variance followed by Duncan's New Multiple Range Test (DNMRT) at the 5% significance level. Results: Neem leaf extract concentration significantly affected the initial mortality time, LT₅₀, and total mortality of H. armigera. The 100 g/L concentration was the most effective treatment, producing an initial mortality time of 12.00 hours, an LT₅₀ of 54.00 hours, and a total mortality of 82.50%. However, its total mortality did not differ significantly from that of the 75 g/L concentration. Conclusions: Neem leaf extract at 100 g/L water showed the highest effectiveness against H. armigera larvae under laboratory conditions. Further field evaluation is required to confirm its effectiveness under field conditions]]>
