Larvicidal Properties of Citrus hystrix DC Fruit (Taw-Shaut-Khar-Thee) Extracts against Aedes aegypti Larvae Collected from Different Townships of Yangon

The present study aimed to evaluate the larvicidal and ovicidal activities of ethanol extracts of dried fruits, internal fruit materials and peels of Citrus hystrix DC against Aedes aegtpti larvae from Dagon (North) and Hlinethaya Townships in Yangon Region from May 20l5 to December 2016. The 3rd and 4th stage larvae were exposed for 24 hours to various concentrations of ethanol extracts of different parts of the Citrus hystrix fruit. The dry fruit extract resulted in significantly higher mortality of 100% and 96.4% in Aedes larvae collected from Dagon (North) and Hlinethaya, respectively (P<0.05). The mortality of Aedes larvae in peel extract was found to be 92.5% in Hlinethaya and 94.4% in Dagon (North), respectively. The extract of Citrus hystrix DC fruit was very effective to kill Aedes larvae collected from Dagon (North). When compared with each other, slightly higher mortality of larvae from Dagon (North) was observed at 0.l5 g/100 m1 concentration of all extracts than that of larvae from Hlinethaya. Ovicidal test found 100% protection to lay their eggs at 0.0l25 g/l00 ml dose and persistency test found 100% mortality of 3rd and 4th instar Aedes larvae up to 6 days at a dose of 0.2 g/100 ml fruit extract. The LC50 and LC90 values of 0.0343 g, 0.0415 g, 0.0231 g, and 0.1256 g, 0.1584 g, 0.0742 g for peel, internal material and fruit extracts, respectively, on Aedes larvae from Dagon were found to be lower than 0.0396 g, 0.0552 g, 0.0280 g and 0.1408 g, 0.2322 g, 0.1060 g, respectively, from Hlinethaya. The findings of the present study revealed that the ethanol extract of the fruit of Citrus hystrix DC has strong larvicidal, ovicidal and long-term persistency activity on Aedes mosquitoes as a good source of preparations for mosquito control. The study may contribute to a reduction in the application of synthetic insecticides, which in turnincreases the opportunity for natural control of various medically important insects by botanical insecticides.