Studies on the efficacy of Toxorhynchites larvae and three larvivorous fish species for the control of Aedes larval populations in water-storage tanks in the Matale district of Sri Lanka.
AbstractA study was conducted to compare the feeding efficacy of Toxorhynchites larvae (L3 & L4) and three larvivorous fish species on Aedes larvae. Ground-level cement water-storage tanks (20%–80%) and water-storing barrels (8.33%–54.55%) formed the majority of Aedes-positive outdoor containers. Ae. albopictus, Ae. macdougali and Ae. vittatus were recorded in water-storage tanks, with Ae. macdougali being dominant. In the laboratory, the consumption rate (time to devour 10 Ae. albopictus L3 larvae in a vessel of 78.57 cm2 of surface area) for Toxorhynchites was significantly lower (mean time of 330 minutes) than for any of the tested fish species, Poecilia reticulata (Guppy), Puntius bimaculatus (Ipilli Kadaya) and Rasbora caveri (Dandiya), which needed 16.67, 27.33 and 24 minutes respectively. There were no significant differences (P=0.062) between the consumption rates of the three fish species. A field study was carried out to determine the feeding efficacy of Toxorhynchites larvae, P. reticulata, P. bimaculatus and R. caveri on Aedes larval populations in outdoor cement tanks by noting the percentage reduction of Aedes larvae per 100 cm2 surface area after one week. Toxorhynchites larvae caused a 20%–83.33% reduction with 1–8 larvae per tank. A complete reduction (100%) was achieved with P. bimaculatus and R. caveri with 1–3 fish per tank. P. reticulata showed similar results, but with 90% reduction being achieved once with two fish per tank. There was a higher possibility of losing Tx. larvae than the fish species during the removal of water by the householders. The efficiency of the three fish species for consuming Aedes larvae was greater than that with Tx. larvae. It appears feasible to use Puntius bimaculatus, Rasbora caveri and Poecilia reticulata for controlling Aedes breeding in outdoor cement water-storage tanks in Sri Lanka.
Wijesinghe, W M G S, Wickramasinghe, M B, Kusumawathie, P H D, Jayasooriya, G A J S K & De Silva, B G D N K. (2009). Studies on the efficacy of Toxorhynchites larvae and three larvivorous fish species for the control of Aedes larval populations in water-storage tanks in the Matale district of Sri Lanka.. WHO Regional Office for South-East Asia.. http://www.who.int/iris/handle/10665/170734