2.5. Larval bioassays
2.5.1. Laboratory trials
Efficacy of 1% temephos sand granules was tested against Ae. aegypti
and Ae. albopictus larvae under laboratory conditions. Each of
25 cement tanks (20 cm 20 cm) was filled with 10 L of dechlorinated
water and 1 g of temephos was added to give the WHO recommended
concentration of 1 ppm. Bioassays were carried out
using three randomly selected tanks as replicates for each time
point. Twenty late third instar larvae were introduced to each of
tank and grounded fish food was given as larval food. Mortalities
were recorded after a 24 h exposure period. Control experiments
were done in 10 L dechlorinated water alone. Initially the bioassays
were conducted weekly. Once the larval survival was initiated, bioassays
were conducted daily.