<![CDATA[Dengue keeps spreading through Aedes aegypti, and creeping resistance to synthetic larvicides such as temephos (Abate) has renewed interest in botanical alternatives. This study examined the larvicidal potential of ethanol extract from langsat leaves (Lansium domesticum var. pubescent), a plant already known to contain alkaloids, saponins, and terpenoids. Leaves were dried, macerated in ethanol, and concentrated by rotary evaporation before being diluted into four test concentrations. A completely randomized design was used with six groups — a negative control, a positive control (1% abate), and extract concentrations of 20%, 30%, 40%, and 50% — each with three replicates of 25 third-instar Aedes aegypti larvae, observed over 24 hours at six time points. Abate eliminated its entire larval population almost immediately, confirming assay validity. The extract itself produced a modest, dose-dependent effect: cumulative mortality rose from 38.67% at 20% and 30% concentrations to 43.99% at 40% and 53.77% at 50%. Two-way ANOVA followed by LSD testing showed that both concentration and observation time significantly affected mortality; the negative control differed significantly from the positive control and the 50% extract group, while the three lower concentrations did not differ from each other. Probit analysis placed LC50 at 45.24% (95% CI 42.67–48.44%) and LC90 at 67.57% (95% CI 60.25–84.83%), classifying the extract as moderately toxic on both measures. Langsat leaf extract thus shows measurable, if still limited, promise as a plant-based supplement to synthetic larvicides for dengue vector control.]]>
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