Adeleke M A, Popoola S A, Agbaje W B, Adewale B, Adeoye M D, Jimoh W A
Department of Biological Sciences, Crescent University, Abeokuta, Nigeria.
Tanzan J Health Res. 2009 Oct;11(4):250-2. doi: 10.4314/thrb.v11i4.50198.
Botanical larvicides have featured prominently as alternative to synthetic chemical insecticides which are less degradable and toxic to non-target organisms. The larvicidal potentials of the seed oils of Pterocarpus santalinoides and Tropical Manihot species (TMS 30572) were investigated in the laboratory against larvae of Aedes aegypti. The seed oil of each plant was extracted using n-hexane and was graded into different concentrations; 30, 60, 90, 120 and 150 ppm. The toxicity of each of the concentrations was evaluated against 3rd instar larvae of A. aegypti and tadpoles (Buffo spp) as non target aquatic fauna. Both oils were toxic to the larvae though at higher concentrations (120 ppm and 150 ppm) after 24 hours of exposure. The oil of P. santalinoides was more toxic to the larvae (LC50 104.0 ppm and LC90 184.5 ppm) than oil of TMS (LC50 113.5 and LC90 201.2) but the difference in the lethal doses was not statistically significant (P > 0.05). However, mortality was not recorded at any of the graded concentrations in both oils against tadpoles. The results therefore suggest that the seed oils of both plants could be incorporated as botanical insecticides against mosquito vectors with high safety to non-target organisms.
植物杀幼虫剂作为合成化学杀虫剂的替代品备受关注，合成化学杀虫剂降解性较差且对非目标生物有毒。在实验室中研究了紫檀木和热带木薯品种（TMS 30572）种子油对埃及伊蚊幼虫的杀幼虫潜力。每种植物的种子油用正己烷提取，并分为不同浓度：30、60、90、120和150 ppm。评估了每种浓度对埃及伊蚊三龄幼虫和作为非目标水生动物的蝌蚪（蟾蜍属）的毒性。两种油对幼虫都有毒性，不过在暴露24小时后，在较高浓度（120 ppm和150 ppm）时才有此效果。紫檀木种子油对幼虫的毒性（LC50为104.0 ppm，LC90为184.5 ppm）比TMS种子油（LC50为113.5，LC90为201.2）更大，但致死剂量的差异无统计学意义（P > 0.05）。然而，两种油在任何分级浓度下对蝌蚪均未记录到死亡情况。因此，结果表明这两种植物的种子油都可作为植物杀虫剂用于防治蚊媒，且对非目标生物具有高安全性。
