title: Insecticidal activity of the essential oil from fruits and seeds of Schinus terebinthifolia Raddi against African malaria vectors.
abstract: BACKGROUND
  Alternative insecticides for the control of malaria and filarial vectors are of paramount need as resistance is increasing among classes of insecticides currently in use in the public health sector. In this study, mosquitocidal activity of Schinus terebinthifolia essential oil against Anopheles gambiae s.s., An. arabiensis and Culex quinquefasciatus was assessed in laboratory, semi- field and full- field conditions
  
  
  METHODS
  Twenty third instar larvae of both Anopheles gambiae s.s. and Cx. quinquefasciatus were exposed to different dosages of plant extract in both laboratory and semi- field environments. Observation of the mortality response was assessed at intervals of 12, 24, 48 and 72 hours. Adult semi- gravid female mosquitoes were exposed to papers treated with S. terebinthifolia and compared with WHO standard paper treated with alphacypermethrin (0.05%).
  
  
  RESULTS
  Gas chromatography, coupled to mass spectrometry, identified 15 compounds from S. terebinthifolia extracts, the most abundant identified compound was δ-3-carene (55.36%) and the least was γ-elemene (0.41%). The density of the oil was found to be 0.8086 g/ml. The effective dosages in the insectary ranged from 202.15 to 2625.20 ppm and were further evaluated in the semi- field situation. In the laboratory, the mortality of Cx. quinquefasciatus ranged from 0.5 to 96.75% while for An. gambiae s.s it was from 13.75 to 97.91%. In the semi- field experiments, the mortality rates observed varied for both species with time and concentrations. The LC50 and LC95 value in the laboratory was similar for both species while in the semi- field they were different for each. In wild, adult mosquitoes, the KT50 for S. terebinthifolia was 11.29 minutes while for alphacypermethrin was 19.34 minutes. The 24 hour mortality was found to be 100.0% for S. terebinthifolia and 75.0% for alphacypermethrin which was statistically significant (P < 0.001).
  
  
  CONCLUSIONS
  The efficacy shown by essential oils of fruits and seeds of S. terebinthifolia has given an opportunity for further investigation of individual components of these plant extracts and to evaluate them in small- scale field trials.
authors: Tropical Pesticides Research Institute, Division of Livestock and Human Disease Vectors Control, Mosquitoes Section, POBox 3024, Arusha, Tanzania. pat.kweka@gmail.com
authors: Eliningaya J
authors: EJ
authors: Kweka
authors: Mramba
authors: M
authors: Nyindo
authors: Franklin
authors: F
authors: Mosha
authors: Ary G
authors: AG
authors: Silva
mesh_terms: D027926:Anacardiaceae / Q000737:chemistry*; D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D003465:Culex / Q000187:drug effects*; D004199:Disease Vectors; D005260:Female; D005638:Fruit / Q000737:chemistry; D007306:Insecticides / Q000302:isolation & purification / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D009822:Oils, Volatile / Q000302:isolation & purification / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D007306:Insecticides; D009822:Oils, Volatile