Insecticidal Activity of Garlic and Onion Essential Oils against Pseudotheraptus devastans in Coconut
Kouadio Jean Marc KOFFI *
Nangui Abrogoua University, UFR-SN, 02 BP 801 Abidjan 02, Ivory Coast and National Centre for Agricultural Research, Marc DELORME Research Station, 07 BP 13 Abidjan 07, Ivory Coast.
Germain Elisabeth Cynthia OCHOU
National Centre for Agricultural Research, Marc DELORME Research Station, 07 BP 13 Abidjan 07, Ivory Coast.
Koffi Fernand Jean-Martial KASSI
Félix Houphouët-Boigny University, Biosciences Training and Research Unit, 22 BP 582 Abidjan 22, Ivory Coast.
N'klo François HALA
National Centre for Agricultural Research, Marc DELORME Research Station, 07 BP 13 Abidjan 07, Ivory Coast.
Bi Tra Serge DOUBI
National Centre for Agricultural Research, Marc DELORME Research Station, 07 BP 13 Abidjan 07, Ivory Coast.
Kouadio Dagobert KRA
Nangui Abrogoua University, UFR-SN, 02 BP 801 Abidjan 02, Ivory Coast.
Kouassi ALLOU
National Centre for Agricultural Research, Marc DELORME Research Station, 07 BP 13 Abidjan 07, Ivory Coast.
*Author to whom correspondence should be addressed.
Abstract
Pseudotheraptus devastans (Heteroptera: Coreidae), commonly known as the coconut bug, is a major pest of coconut palms in Côte d'Ivoire. All larval stages and adults cause damage by their bites, resulting in either deformation of young nuts or their fall. As part of the search for a strategy to protect these nuts from attack, an evaluation of the effectiveness of essential oils from Allium sativum and Allium cepa was tested on out. The study was conducted at the coconut research station of the National Centre for Agricultural Research in Côte d'Ivoire. The essential oils extracted from the two aromatic plants were tested by contact using a hand sprayer at different concentrations on the eggs, larvae and adults of P. devastans at a temperature of 26.39 ± 1.50°C and a relative humidity of 87.85 ± 2.15%. These essential oils have insecticidal properties against P. devastans. The essential oil of A. sativum had LC (50) and LC (90) values of 0.27 ± 0.6% ; 11.24 ± 0.57% for larvae and 3.82 ± 0.07% ; 11.28 ± 0.17% for adults, whereas that of A. cepa had LC (50) and LC (90) values of 0.59 ± 0.51% ; 38.16 ± 0.93% for larvae and 4.84 ± 0.10% ; 20.05 ± 0.25% for adults. The essential oil of A. sativum was therefore the most toxic.
Keywords: Coconut bug, essential oil, garlic, onion