Effects of Extracts from Four Pesticidal Plants on the Management of the Sugarcane Stem Borer Eldana saccharina Walker in Côte d'Ivoire
Ouattara Dadjo *
Doctoral School of Science, Technology and Sustainable Agriculture, Félix Houphouët Boigny University, Abidjan, Côte d'Ivoire and UFR Biosciences/Laboratory of Biotechnology, Agriculture and Valorisation of Biological Resources/UPR Plant Physiology and Pathologies, Félix Houphouët Boigny University, Abidjan, Côte d'Ivoire.
Kouame Konan Didier
UFR Biosciences/Laboratory of Biotechnology, Agriculture and Valorisation of Biological Resources/UPR Plant Physiology and Pathologies, Félix Houphouët Boigny University, Abidjan, Côte d'Ivoire.
Yao Kouadio Jacques Edouard
Department of Agroforestry, Jean Lorougnon Guédé University, Daloa, Côte d'Ivoire.
Yao Kouakou
Department of Agricultural Studies, Sucrivoire, PO Box 100, Borotou-Koro, Côte d’Ivoire.
Kone Daouda
UFR Biosciences/Laboratory of Biotechnology, Agriculture and Valorisation of Biological Resources/UPR Plant Physiology and Pathologies, Félix Houphouët Boigny University, Abidjan, Côte d'Ivoire.
*Author to whom correspondence should be addressed.
Abstract
The stem borer Eldana saccharina Walker causes substantial production losses in the sugarcane estates of Côte d'Ivoire, where its control still relies largely on synthetic chemical insecticides that are harmful to human health and the environment. The present study aimed to evaluate the effects of extracts from pesticidal plants on infestation rates and the agro-technological parameters of sugarcane. A field trial was conducted under natural infestation conditions, using a randomised complete block design (Fisher blocks) with thirteen treatments and four replications. The essential oils of Cymbopogon citratus (DC.) Stapf, Ocimum gratissimum L. and Zingiber officinale Roscoe, as well as an oil concentrate of Azadirachta indica A. Juss. (A. indica OC), were applied at doses of 1, 2 and 3 ml · l−1. Three applications were made at fifteen-day intervals from the fifth month of vegetation, and the phytosanitary and agro-technological parameters were assessed at harvest. The microplots treated with the essential oils of C. citratus and Z. officinale, as well as with the A. indica OC, were significantly less infested than the untreated control microplots. Those treated with C. citratus essential oil recorded, on average, the lowest percentages of bored internodes (3.15%) and bored stalks (35.97%); they also produced the longest stalks and the highest cane and extractable sugar yields. These extracts improve the agro-technological parameters of sugarcane and can be used as bio-insecticides in the control of E. saccharina Walker.
Keywords: Sugarcane, Eldana saccharina, stem borer, pesticidal plants, essential oils, botanical insecticides, Cymbopogon citratus, Zingiber officinale, Ocimum gratissimum, Azadirachta indica