Chemical Composition and Spectrum of Insecticidal Activity of the Essential Oils of Ocimum gratissimum L. and Cymbopogon citratus Stapf on the Main Insects of the Cotton Entomofauna in Côte d'Ivoire |
| |
Authors: | Koffi Christophe Kobenan Kouadio Kra Norbert Bini Malanno Kouakou Ibrahime Sinan Kouadio Gokhan Zengin Germain Elisabeth Cynthia Ochou Nina Reine Kosso Boka Philippe Menozzi Ochou Germain Ochou Acka Emmanuel Dick |
| |
Institution: | 1. Félix Houphouët-Boigny University (UFHB), UFR Biosciences, Laboratory of Biotechnology, Agricultural and Biological Resources Valorisation, 22 BP 582, Abidjan, 22 Côte d'Ivoire;2. National Center of Agronomic Research (CNRA), Cotton Research Station, Laboratory of Entomology, 01 BP 633 Bouaké 01, Côte d'Ivoire;3. Physiology and Biochemistry Research Laboratory, Department of Biology, Science Faculty, Selcuk University, Campus, Konya, Turkey;4. National Center of Agronomic Research (CNRA), Cotton Research Station, Laboratory of Entomology, 01 BP 633 Bouaké 01, Côte d'Ivoire
Agricultural Research Center for International Development (CIRAD), Research Unit 115 AIDA (Agroecology and Sustainable Intensification of Annual Crops) –, France |
| |
Abstract: | Among the alternatives to environmentally toxic and socio-economically unacceptable chemical pesticides, essential oils from Ocimum gratissimum and Cymbopogon citratus were tested on the main pests and beneficial insects of the cotton plant in Côte d′Ivoire. After extraction and chemical analysis of the essential oils, field trials were carried out using a Fisher block system with three treatment repetitions where their effects compared with those of a registered synthetic insecticide (IBIS A 52 EC). Foliar applications of the products were carried out in accordance with the cotton plant protection extension programme in Côte d′Ivoire from the 45th to the 115th day after plant emergence, with one application every fortnight. Twenty-three and forty compounds representing about 96 and 99 % of the oil composition of O. gratissimum and C. citratus respectively were elucidated. The most abundant compounds were p-cymene and thymol (O. gratissimum) and myrcene, neral and geranial (C. citratus). The essential oil of O. gratissimum at concentrations of 2 and 5 % showed insecticidal activity on all pests (biting-sucking and carpophagous), except the phyllophagous Syllepte derogata. C. citratus, at a low concentration (1 %), was particularly toxic to whiteflies (Bemisia tabaci), however, it favoured the action of beneficial insects, specifically black ants and ladybirds in the cotton plots, unlike the chemical product. EO of O. gratissimum (1.60 and 4.62 mg GALAE/g, respectively) and C. citratus (2.26 and 2.78 mg GALAE, respectively) exhibited also significant acetyl and butyryl cholinesterase inhibitors. Insecticide formulations based on the essential oils of O. gratissimum and C. citratus offer favourable prospects for their use in cotton cultivation as an alternative to chemical pesticides. |
| |
Keywords: | insecticide essential oils Ocimum gratissimum Cymbopogon citratus cholinesterase |
|
|