ABSTRACT

This study investigated the larvicidal efficacy of aqueous extract Pennisetum purpureumagainst Aedes larvae and the evaluation of the phytochemical constituent present in both plant extract was carried out to identify phytochemicals that possess larvicidal activity. Ten healthy laboratory breed larvae of Aedes sp. were tested using three different concentrations (500, 750 and 1000ppm) and a simultaneous control. Larvae were exposed to various test concentration for a period of 72 hours. Moribund larvae were counted at an interval of 24, 48 and 72 hours respectively. The result showed The mortality of Aedes larvae exposed to 750ppm of the test concentration of Pennisetum purpureum showed significant difference (p<0.05). However larval mortality resulted from continuous exposure to 500 and 1000ppm the test concentration between 24-72 hours of exposure had no significant difference. (p>0.05). Highest mortality was observed at the highest concentration (1000ppm) of test concentration of Pennisetum purpureum. Lethal concentration of Pennisetum purpureum against Aedes larvae at various time interval were determined. At 24 hours the LC₅₀ and LC₉₀ were 1422.88ppm and 6510.08ppm. At 48 hours the LC₅₀ and LC₉₀ were 1089.64 ppm and 4320.88 ppm. At 72 hours LC₅₀ and LC₉₀ were 1063.67ppm and 5975.30 respectively. Qualitative analysis revealed the presence of Carbohydrates, Alkaloids, Saponins, Reducing sugar and Tannins in Pennisetum purpureumextract. The efficacy of both plant extract as seen from the study showed promising larvicidal potency. The findings of the present investigation revealed that the leaf extract of Pennisetum purpureum possess larvicidal showed larvicidal activity against Aedes sp.