Insecticidal Activities of Plants Extract Against Malaria Vectors in Hadiya Zone, Ethiopia

Environmental changes due to global warming and human activities have negatively impacted malaria vector control in Hadiya zone, Ethiopia. Plants contain anthraquinoes. Flavonoids, glycosides, phenol, saponin, steroids, tannin, and terpenes that are target specific, rapidly biodegradable, ecofriendly, and less toxic to human health. The objective of the study was to evaluate the insecticidal activities of Azadirachta indica (neem) and Allium sativum L. (garlic) ethanol extracts against malaria vectors in the study area. Then, 20 g from each (A. indica and A. sativum L.) were extracted separately by ethanol solvents. The phytochemical analysis was evaluated from the crude sample based on standard methods. Then, insecticidal activities were evaluated by introducing the fourth instar larva at 50, 100, 150, 200, and 250 ppm concentrations, and data were subjected to probit analysis to determine the LC₅₀ and chi-square test to check the significance of the mortality by R statistical software. The presence of phytochemical tests such as alkaloids, saponin, tannin, phenol, anthraquinoes, flavonoids, glycosides, steroids, terpenes, and flavonoids was obtained. The mortality of malaria vectors due to ethanol extract of A. indica and A. sativum was observed. The highest (90.66%) mortality was observed in the ethanol extract of A. sativum at 250 ppm concentration. A. sativum extracts have a significant effect only on the mortality of Anopheles gambiae s.l (X ² = 13.6, p = 0.008687) and Anopheles pharoensis (X ² = 11.002, p = 0.02655), but A. indica have a significant effect only on the mortality of An.pharoensis (X ² = 14.26, p = 0.00651). The lowest LC₅₀ (39 ppm) was observed in the ethanol extract of A. sativum. So, A. sativum extract was highly toxic than A. indica extract and more effective in the reduction of malaria vectors but further studies will be conducted to determine the insecticidal activities at pupa and adult stages.