Mosquito Repellency and Toxicity Effects of Hyptis suaveolens (Leaves) Against Culex Mosquito

Abstract

Human pathogens that are transmitted by insects are a global problem, particularly those vectored by mosquitoes. Mosquitoes are the most important group of insect vectors able to transmit several diseases, including malaria, dengue and filariasis, especially in the local environment, hence the need to find safe, locally available and environmentally benign control measures. Hyptis suaveolens is an exotic plant that has high adaptability and tolerance of changes in abiotic factors, with a particularly high presence in the northern regions of Nigeria. This study aimed at analysing the repellency and toxicity effects of Hyptis suaveolens on Culex mosquitoes. Leaves of Hyptis suaveolens were obtained from Katsina-Mani Road. Using the prepared plant extract, phytochemical screening, repellency and toxicity tests were carried out. The result of phytochemical screening revealed the presence of alkaloids, flavonoids, glycosides, reducing sugar, steroids, saponins, and tannins. Total number of mosquitoes landed on the control arm was 15 (60%), followed by arm treated with 20% repellent cream, which was 3 (12%), while none (0%) landed on 40%, 60% and 100% arm treated with repellent cream. The toxicity of Hyptis suaveolens leaves against Culex mosquitoes was recorded at different concentrations, where the effect of Hyptis suaveolens leaf smoke was higher at higher concentrations and lower at lower concentrations. Further, 100% toxicity was obtained at 80 and 100% concentrations. This study revealed that an extract obtained from dried leaves of Hyptis suaveolens had the ability to repel adult Culex mosquitoes even at low concentration (40%).