LABORATORY EVALUATION OF EXTRACT FROM PEELS AND SEEDS OF SOME Citrus species AGAINST Anopheles MOSQUITOES (DIPTERA: CULICIDAE)

Abstract

Anopheles mosquito has been identified as vector of medical and veterinary importance due to their ability to transmit parasitic diseases such as Malaria and Filariasis. Malaria is responsible for the death of over one million people every year. Synthetic chemical insecticides has been in used for decades in controlling this vector, but due to resurgence of insect vector, insect resistance and their toxic hazards to human, there is need to find an alternative way in tackling this vector of parasitic diseases. The present study aimed to evaluate ethanolic extract from peels and seeds of Citrus sinesis, Citrus limonum and Citrus aurantifolia in controlling Anopheles mosquitoes. The extracts were prepared using 99% ethanol as solvent, while the control was exposed to the solvent (ethanol) alone. The adultcidal potential of each extract at different concentration (5%, 10%, 15%, 20% and 25%) of exposure (20, 40 and 60minutes) was assessed against malaria vector (Anopheles spp) by evaluating the toxicity effects on thirty (30) adults stage of the vector with the help of sprayer inside enclosed aerated boxes. The extracts were found to be effective as the concentration ascend with different degree of effectiveness based on time of exposure. Insecticidal activity of 25% concentration of C. aurantifolia peel extract was better after 60minutes (62.22% mortality was recorded) more than the peels and seeds of other Citrus used. The effectiveness of C. limonum seed and C. aurantifolia seed are the same (Both shown 50% mortality at 25% concentration). The toxicity increase with respect to time of exposure, the best toxicity estimation of LC50 (lethal concentration at which 50% sample will be eliminated) was 22.05% from the extract of C. aurantifolia peels, while that of LC95 was 112.27% from the C. limonum peels extract after 60 minutes of application. In conclusion, phytochemical analysis of these extracts showed the presence of Terpernoid, Flavonoid, Tannins, Cardiac glycosides and Saponins. The different levels of effectiveness of the Citrus peels and seeds in this study may be due to the various level of phyto – constituent present in the extracts.