Laboratory Evaluation of Extract from Peels and Seeds of Some Citrus Species against Anopheles Mosquitoes (Diptera: Culicidae)

Abstract

Mosquitoes are the most important group of insects known for their public health importance. Efforts to eradicate this disease involve elimination of the vector with natural base insecticides which are safer when compared to synthetic insecticides which are harmful to human. Toxicity effect of extracts from peels and seeds of Citrus sinesis , Citrus aurantifolia and Citrus limonum were evaluated against adult Anopheles mosquitoes at different concentrations and time of exposure; 20, 40 and 60 minutes. The peels and seeds were air dried for 15 days before pulverization. The pulverized peels and seeds were subjected to extraction using soxhlet apparatus and ethanol as solvent. The stock solutions were prepared by adding 0.1 mL of extract to 9.9 mL of ethanol to make 1% concentration. The following different concentrations 5, 10, 15, 20, and 25% of the extract were prepared as followed; 0.5, 1.0, 1.5, 2.0 and 2.5 mL of the extract were dissolved in 9.5, 9.0, 8.5, 8.0 and 7.5 mL of the solvent (Ethanol) respectively with three (3) replicates for each concentration, while 10 mL of ethanol was used as the control (0%). The qualitative and quantitative analyses of the phytochemical constituents were analyzed. The efficacy of the extracted oils was tested on adult female Anopheles mosquitoes. At 25% concentration, C. aurantifolia peel extract recorded 62.22% mortality at 60 minutes while the seed extract recorded 50% mortality at the same concentration and time. The toxicity increased in respect to time of exposure, the toxicity estimation of LC 50 was 22.05% from the extract of C. aurantifolia peels and LC 95 was 112.27% for C. limonum peels extract after 60 minutes of application. The potency of the Citrus peels and seeds extracts may be as a result of the phytochemical constituents present in them. These results suggest that the Citrus peel and seed extracts have the potential to be used as ideally in eco-friendly approach for the control of the vector control programs.