INSECTICIDE SUSCEPTIBILITY OF AEDES AEGYPTI LARVAE TO BACILLUS THURINGIENSIS ISRAELENSIS AND JUVENILE HORMONE IN DENGUE EPIDEMIC AREAS OF SAMUTSONGKHRAM, THAILAND

Abstract

Dengue hemorrhagic fever (DHF) remains one of Thailand’s main public health problems.
Samutsongkhram is one of the areas undergoing an epidemic of this disease. To control this disease, public
health officers focus on regulating the population of Aedes aegypti larvae. The aims of this research were to
study the susceptibility of Ae. aegypti to Bacillus thuringiensis israelensis (Bti) and juvenile hormone, in
order to end the spread of this disease in three epidemic DHF outbreak sub-districts of Ladyai, Suanluang and
Jompuak. The results revealed that Ae. aegypti is susceptible to Bti and juvenile hormone in all areas, with a
100% death rate. Exposure to Bti eradicated the larvae in a very short time of less than 18 hours. In addition,
juvenile hormone can completely hinder the growth of Ae. aegypti to adult stages. The results demonstrate
the effectiveness of these agents for mosquito larvae eradication. Therefore, insecticidal bacterium and
juvenile hormone may be an option to reduce the number of DHF patients in Samutsongkhram, Thailand.