Laboratory evaluation of extract from peels and seeds of some Citrus species against Anopheles mosquitoes (Diptera: Culicidae)

摘要

Mosquitoes are the most important group of insects known for their public health importance. Efforts toeradicate this disease involve elimination of the vector with natural base insecticides which are saferwhen compared to synthetic insecticides which are harmful to human. Toxicity effect of extracts frompeels and seeds of Citrus sinesis, Citrus aurantifolia and Citrus limonum were evaluated against adultAnopheles mosquitoes at different concentrations and time of exposure; 20, 40 and 60minutes. The peelsand seeds were air dried for 15 days before pulverization. The pulverized peels and seeds were subjectedto extraction using soxhlet apparatus and ethanol as solvent. The stock solutions were prepared by adding0.1 mL of extract to 9.9mL of ethanol to make 1% concentration. The following different concentrations5, 10, 15, 20, and 25% of the extract were prepared as followed; 0.5, 1.0, 1.5, 2.0 and 2.5mL of theextract were dissolved in 9.5, 9.0, 8.5, 8.0 and 7.5mL of the solvent (Ethanol) respectively with three (3)replicates for each concentration, while 10mL of ethanol was used as the control (0%). The qualitativeand quantitative analysis of the phytochemical constituents were analysed. The efficacy of the extractedoils were tested on adult female Anopheles mosquitoes. At 25% concentration, C. aurantifolia peelextract recorded 62.22% mortality at 60 minutes while the seed extract recorded 50% mortality at thesame concentration and time. The toxicity increased in respect to time of exposure, the toxicityestimation of LC50 was 22.05% from the extract of C. aurantifolia peels and LC95 was 112.27% for C.limonum peels extract after 60 minutes of application. The potency of the Citrus peels and seeds extractsmay be as a result of the phytochemical constituents present in them. These results suggest that the Citruspeel and seed extracts have the potential to be used as ideally in eco-friendly approach for the control ofthe vector control programmes.