title: Chemical Composition of the Essential Oil of Nigeria Grown Hoslundia opposita Vahl (Lamiaceae) Dried Leaves and Its Bioactivity against Cowpea Seed Bruchid.
abstract: Due to several ecological and human hazards of synthetic pesticides in postharvest crop protection, there is the need to search for eco-friendly alternatives. In this study, chemical composition and insecticidal activities of essential oil (EO) obtained from Hoslundia opposita dried leaves were evaluated against cowpea seed bruchid. Eight constituents, predominated by oxygenated monoterpenes (78.86%), were identified using Gas Chromatography (GC)/MS. The constituents were 1,8-cineole (1; 61.15%), followed by α-terpineol (2; 16.81%), β-phellandrene (3; 13.24%), β-farnesene (4; 3.55%), α-pinene (5; 1.89%), Germacrene D (6; 1.83%), cis-sabinene hydrate (7; 0.90%) and caryophyllene (8; 0.63%). In fumigation bioassay, at 6 h after exposure (HAE), 0.78 ml EO/l air caused 35.33% mortality which was significantly lower than 60.90% and 63.6% observed at 3.15 and 6.25 ml/l air, respectively. Mortality reached 90.0% at 24 HAE regardless of the applied concentration. Lethal time for 50% of the bruchids (LT50) at concentration of 0.78 ml/l air (6.89 h) was higher than the LT50at 3.15 and 6.25 ml/l air (4.72 and 4.44 h, respectively). H. opposita EO reduced Callosobruchus maculatus oviposition, while progeny emergence observed in EO-treated seeds (2.42 - 25.73) was significantly (P < 0.05) lower than 51.56 observed in control. The results confirm H. opposita EO's potentials for control of cowpea bruchids.
authors.affiliation: Department of Crop and Environmental Protection, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, 210001, Nigeria.
authors.forename: Samuel Adelani
authors.initials: SA
authors.lastname: Babarinde
authors.affiliation: Department of Crop Protection, Federal University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria.
authors.forename: Olufemi Olutoyin Richard
authors.initials: OOR
authors.lastname: Pitan
authors.affiliation: Department of Biological Sciences, Osun State University, P.M.B. 4494, Osogbo, Nigeria.
authors.forename: Ganiyu Olatunji
authors.initials: GO
authors.lastname: Olatunde
authors.affiliation: Department of Plant Breeding and Seed Technology, Federal University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria.
authors.forename: Michael Oluwole
authors.initials: MO
authors.lastname: Ajala
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000187:drug effects*; D005651:Fumigation; D008401:Gas Chromatography-Mass Spectrometry; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology*; D019686:Lamiaceae / Q000737:chemistry*; D039821:Monoterpenes / Q000032:analysis; D009549:Nigeria; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D012639:Seeds; D000070658:Vigna
chemical_list: D007306:Insecticides; D039821:Monoterpenes; D009822:Oils, Volatile
keywords: 
  Hoslundia opposita
  ; Cowpea bruchid; Fumigant toxicity; Progeny emergence; Reproductive efficiency