title: Larvicidal efficacy of Cryptomeria japonica leaf essential oils against Anopheles gambiae.
abstract: BACKGROUND
  Alternative insecticidal compounds with mortality effect against mosquito life cycle stages are currently needed. The compounds should be biodegradable and nontoxic to non-targeted insects. Plant based larvicides provide effective control of vector populations. This study explored Cryptomeria japonica leaf essential oil larvicidal potency against Anopheles gambiae sensu stricto.
  
  
  METHODS
  Essential oils (12.5 to 200 μg/mL) extracted from C. japonica leaves were evaluated against An. gambiae s.s. larvae in both the laboratory and semi field in 6 replicates for each dose. Larval mortality readings were taken at 12, 24, 48, and 72 h post treatment.
  
  
  RESULTS
  C. japonica leaf essential oil yield was 17.06 ± 0.56 mL/kg and 1.60 ± 0.33% (w/w). GC-FID and GC-MS analyses revealed 22 constituents. Essential oil was more effective against An. gambiae s.s. larvae in the laboratory than in semi field trials. Mortality increased with increasing dosages (12.5 to 200 μg/mL) in the laboratory (31.75 to 100%) and semi field trials (17.75 to 99.5%), respectively. The LC50 value ranged from 5.55 to 63.92 μg/mL in the laboratory, and 8.22 to 134.84 μg/mL in semi field conditions, LC90 value ranged from 41.34 to 205.93 μg/mL in the laboratory and 50.92 to 213.11 μg/mL in semi field conditions.
  
  
  CONCLUSIONS
  This study has demonstrated the potential of C. japonica leaf essential oil to cause mortality effects to An. gambiae s. s. larval populations, however, further studies need to be conducted under field conditions and also with individual active compounds of C. japonica essential oil.
authors.forename: France P
authors.initials: FP
authors.lastname: Mdoe
authors.forename: Sen-Sung
authors.initials: SS
authors.lastname: Cheng
authors.forename: Lucile
authors.initials: L
authors.lastname: Lyaruu
authors.forename: Gamba
authors.initials: G
authors.lastname: Nkwengulila
authors.forename: Shang-Tzen
authors.initials: ST
authors.lastname: Chang
authors.affiliation: Division of Livestock and Human Diseases Vector Control, Tropical Pesticides Research Institute, Ngaramtoni, Off Nairobi Road, P,O, Box 3024, Arusha, Tanzania. pat.kweka@gmail.com.
authors.forename: Eliningaya J
authors.initials: EJ
authors.lastname: Kweka
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D001681:Biological Assay; D032485:Cryptomeria / Q000187:drug effects*; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D007306:Insecticides; D009822:Oils, Volatile; D010938:Plant Oils