Temephos bioassay
Larvicide testing was prepared according to the World Health
Organization (WHO) procedure with a modification on the
applied dose of commercial Abate® 1.1G [1.1% w/w, registered
by BASF (Malaysia) Sdn. Bhd] [8]. The mosquito larvae were
tested against two different dosages of temephos: (1)
recommended dose at 0.012 mg/L and (2) operational dose
that has been used by Department Health of Penang at 1 mg/L
and prepared with ethanol as solvent. A total of 20 late third
and early fourth instar larvae were selected and transferred
into paper cup sized 300 mL using wide-mouthed pipette.
Larvae were left for 1 h prior to the experiment to permit
acclimatization and no additional food was offered. After that
period, any abnormal larvae were replaced with healthy ones.
The larvae were distributed into each 300 mL paper cup containing
50 mL of aged tap water. The experiment was replicated
five times for each concentration tested. Each test was repeated
three times.