LARVICIDAL EFFICACY OF THE AQUEOUS AND METHANOL EXTRACTS

ABSTRACT

Culex mosquitoes constitutes nuisance, disrupt sleep and trigger allergic reactions in people with sensitivity. They are also responsible for the transmission of severe diseases including West Nile virus, Equine encephalitis, and bancroftian filariasis which are detrimental to human health and livestock. For a long time, chemical pesticides have been used extensively to control mosquitoes. Recent research on the insecticidal effectiveness of various chemical insecticide classes on distinct mosquito life stages has revealed the prevalence of resistance established in mosquitoes. Botanical insecticides are environmentally friendly, selective, biodegradable, and have little to no negative impact on non- target organisms. Clove contains a variety of chemical constituents in high concentrations that have antioxidant activity. This study was aimed at investigating the phytochemical constituents present in Syzygium aromaticum and the larvicidal efficacy of its extracts. Test concentrations of 500, 750 and 1000ppm were used at exposure time of 24, 48 and 72 hours. There was no significant difference p>0.05 across the various concentrations at exposure time of 24, 48 and 72hrs in the aqueous extract of Syzygium aromaticum against the larvae of Cx quinquefasciatus.  It was observed in the methanol extract that there was significant difference p<0.005 at 48 and 72hrs of exposure. The LC₅₀ values of the aqueous extract at the various exposure time were 847.80, 739.55 and 739.55. The LC₉₀ values were 3532.28, 2040.40 and 2040.40. While the LC₅₀ values were 1.773.57, 1056.35 and 1026.21 at 24, 48 and 72hrs. The LC₉₀ values were 3058.42, 1512.82 and 1478.33 respectively for the methanol extract.