University of Malaya From the SelectedWorks of Chen Chee Dhang

Abstract. The bioefficacy of a commercial formulation of temephos, Creek ® against Aedes aegypti larvae was studied in the laboratory. Earthen jars were filled with 10 L tap water each. One g of temephos (Creek®) sand granule formulation was added into each earthen jar as recommended by the manufacturer. The final test concentration of Creek ® was 1 mg a.i./L. One earthen jar was filled with 10 L tap water and served as a test control (untreated). Thirty late 3rd or early 4th instar of lab-bred Ae. aegypti larvae were added into each earthen jar. Mortality of the larvae was recorded after 24 hours and percent mortality was calculated. Test was repeated every week. The results showed that complete larval mortality was achieved after 24 hours. The residual effect lasted 15 weeks (105 days), indicating that Creek ® is effective at the dosage recommended by the manufacturer which is 1 mg a.i./L. Dengue fever (DF) and dengue haemorrhagic fever (DHF) are considered the most important and disseminated vector-borne disease of public health importance in tropical, subtropical and temperate regions of the world (Gubler et al., 1998). Millions of people are infected by DF and DHF annually (Jacobs, 2000). Aedes aegypti and Aedes albopictus play a crucial role in the transmission of these infections (Rebecca