Efficacy of Crude Extracts of Mitragyna speciosa Korth. Leaf Against Aedes aegypti (L.) Larvae

Abstract

        Aedes aegypti is a main vector of dengue hemorrhagic fever, a serious public health problem in Thailand. Application of active toxic agents from plant  extracts  as an  alternative  mosquito  control strategy was available from  ancient  times.  In  this  current  research,  the insecticidal of hexane, methanolic and ethanolic crude extracts of Mitragyna speciosa leave were estimated for their  toxicity of  3^rd– 4^th  instar larvae of Aedes aegypti.  The percentage larval mortality was evaluated  after  24, 48 and 72 h exposure at  different  concentrations  (0, 125, 500  and 1,000 mg/L).  It was revealed that   M.  speciosa   leaf   hexane  extract    EXHIBITED   MEDIAN   LETHAL CONCENTRATIONS TO KILL  50%  (LC₅₀)  OF THE TREATED LARVAE IN  24, 48 AND 72 H OF 1,879.22 2,014.22 and 104.03 mg/L. Meanwhile, M. speciosa METHANOLIC  EXTRACT  DISPLAYED  LC₅₀  OF  THE  TREATED  ADULTS IN 24,  48  AND  72 H  OF  404.66  81.14  and  79.00 mg/L  and  ehanolic  extract showed  LC₅₀  of  17,747.43  111.83  and  82.55,  respectively.  Obviously,  no significant  difference in the  mean  total  mortality of AE. AEGYPTI among three solvents in all times of exposure was explored  (p ≥ 0.05).  At a result, crude  extracts  of  M. speciosa  leaf  were  likely  to be further employed in controlling   Ae.  aegypti   larvae   and    other   insects   of   medicinal   and veterinary  importance  in the risk areas.