Larvicidal and Adulticidal Control of Malaria causing Mosquitoes using Eucalyptus globulus, Hyptis suaveolens, and Cymbopogon citratus plants in Quarry sites in Ebonyi State, Nigeria

The escalating challenge of insecticide resistance necessitates the exploration of effective botanical alternatives for mosquito control. This study evaluated the larvicidal and adulticidal activities of Eucalyptus globulus, Hyptis suaveolens, and Cymbopogon citratus plant extracts in three quarry sites across Ebonyi State, Nigeria. Larvicidal and adulticidal activities were tested in the lab and field conditions following WHO guidelines. High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) analysis identified key bioactive compounds. Application of individual plant extracts caused a drastic reduction in larval populations, from approximately 34,600 to 396 larvae in all three sites, representing a 99% reduction. Adulticidal mortality rates for the individual extracts reached up to 100%. The combined extract exhibited synergistic effects, achieving a perfect 100% mortality rate outperforming the individual extracts and a commercial insecticide. Key bioactive compounds were identified.1, 8-cineole was the most consistently effective compound achieving a perfect mortality (100%). Statistical analysis demonstrated a strong positive relationship (R = 0.9111) between extract concentration and mosquito mortality rates and significant results (p = 0.0011). These plants are effective alternatives for mosquito vector control providing foundation for scaling up the application of plant-based insecticides in public health strategies.