Bioactivities of the Peacock Flower Caesapinia pulcherrima (L.) Sw. Against Mosquitoes and Three Stored Product Pests

Abstract

Petroleum ether, chloroform (CHCl₃) and methanol (CH₃OH) extracts of the flowers and leaves of Caesalpinia pulcherrima (L.) were evaluated for their larvicidal activity against Culex quinquefasciatus Say and their repellent activity against three stored grain pests: Tribolium castaneum (Hbst.), Sitophilus oryzae (L.) and Callosobruchus chinensis (L.). The LC₅₀ values ​​of the petroleum ether and CHCl₃ extracts of the flowers were 119.80, 37.34, 25.06, 17.12, and 10.36 ppm and 101.04, 76.67, 66.67, 58.24, and 51.82 ppm, respectively, after 24, 30, 36, 42, and 48 h of exposure. The CHCl₃ leaf extract showed LC₅₀ values ​​of 361.21, 321.10, 245.41, 207.09, and 203.19 ppm after 24, 30, 36, 42, and 48 h of exposure, respectively. Depending on the intensity of larvicidal activity on the mosquito, the extracts can be classified in descending order as follows: petroleum ether (flower) >CHCl₃ (flower) >CHCl₃ (leaf). Extracts of flowers with petroleum ether demonstrated a highly significant repellent effect against adult T. castaneum (p<0.01), extracts of leaves with CHCl₃ and CH₃OH showed a moderately significant repulsion against adult T. castaneum (p<0.05), and extracts of leaves with petroleum ether also showed a moderately significant repulsion against adult S. oryzae (p<0.05).

J. Bio-Sci. 33(2): 77-86, 2025