Larvicidal Activity of Solvent Extracts of Combined Garlic (Allium sativum) and Ginger (Zingiber officinale) against Mosquito Species

Mosquitoes are major vectors of infectious diseases, including malaria and lymphatic filariasis. This study evaluated the larvicidal activity of combined garlic and ginger against mosquito species. Larvae were collected from breeding sites and identified using standard morphological keys. Equal quantities of both plant materials (20 g total) were extracted using aqueous, ethanol, and methanol solvents. Phytochemical screening of the crude extracts was conducted using standard qualitative methods. Larvicidal activity was assessed by exposing ten larvae to extract concentrations of 250, 500, and 750 ppm. Mortality data were analyzed using probit analysis to determine LC₅₀ values, while Pearson's chi-square goodness-of-fit statistics were used to evaluate the adequacy of the fitted probit models using R software. Qualitative phytochemical screening detected the same classes of secondary metabolites across all solvent extracts. Larvicidal activity showed a clear concentration-dependent increase, with methanol extract demonstrating the highest efficacy (up to 96.7 ± 3.3% mortality at 750 ppm), followed by ethanol and aqueous extracts. Probit analysis yielded lower estimated LC₅₀ values for methanol extracts than for ethanol and aqueous extracts in An. gambiae s.l. (180 ppm; 95% CI: 140-230 ppm) and Cx. quinquefasciatus (300 ppm; 95% CI: 240-380 ppm). The model showed good fit across treatments, with non-significant chi-square values (χ2 = 1.87-3.20, p > 0.05), indicating that the fitted probit models adequately described the observed dose-response data. The positive control (malathion) resulted in 100% larval mortality, whereas the negative control (distilled water) showed 0% mortality. Overall, the findings demonstrate that combined garlic and ginger extracts possess promising larvicidal activity under laboratory conditions. However, further studies incorporating additional concentrations, quantitative phytochemical analyses, isolation of active compounds, and field evaluations are required before practical applications.