2.8 Biological Control of Mosquitoes
2.9.1 Toxorhynchites Larvae
52 2.9 Other Biocontrol Agents of Mosquitoes
53 Tx. splendens larvae is a good biocontrol agent in control of mosquito populations as Tx.
splendens larvae are environmentally friendly and attack larval stages. In Singapore as reported by Chan, (1968) three prey species were found with Tx. splendens larvae such as Ae. albopictus, Culex spp. and chironomids. The normal prey for Tx. splendensis is Ae.
albopictus larvae. Tx. splendens larvae are more effective in the control of Ae. albopictus in rural areas than Ae. aegypti which are found in urban settings. It is because Tx. splendens larvae are rarely found in populated areas which are in urban areas. They also depend on nectar of flowers thus areas with vegetation are their preferences habitat.
54 Table 2.7 Summary of reports on the use of Toxorhynchites splendens as
biocontrol agents for mosquito species
No. Biocontrol agents Prey Country / Reference 1. Toxorhynchites
Armigeres subalbatus and Cx.
India (Aditya et al. 2007)
2. Rhantus sikkimensis and
4th instars Cx.
India (Aditya et al. 2006)
3. Toxorhynchites splendens
Ae. albopictus larvae Malaysia (Nyamah et al.
4. Toxorhynchites rutilus Mosquito larvae India (Sahib, 2011) 5. Toxorhynchites
Ae. albopictus and Ae.
Singapore (Chan, 1968)
6. Toxorhynchites rutilus Ae. aegypti larvae USA (Lounibos et al. 1998) 7. Toxorhynchites
Ae. aegypti , Ar.
subalbatus, An. stephensi and Cx.
India (Pramanik & Raut, 2003)
8. Toxorhynchites violaceus
Ae. aegypti larvae Brazil (Albeny et al. 2011) 9. Toxorhynchites
Ae. aegypti larvae Indonesia (Annis et al.
1990) 10. Toxorhynchites
Ae. polynesiensis larvae French Polynesia (Mercer et al. 2005)
11. Toxorhynchites brevipalpis
Ae. aegypti larvae Tanzania (Trpis et al. 1973)
Bti (Bacillus thuringiensis israelensis) was commoly used and applied in control of mosquito larvae and recently, B. sphaericus larvicide has been successfully applied in various mosquito control (Table 2.8). The used of Bti (Bacillus thuringiensis israelensis) against Ae. aegypti in earthen jar containing landscaping aquatic plant showed that container with aquatic plants for landscaping should be treated more frequently than
55 container without aquatic plant. The mortality ranged from 77.34% -100% for jars with aquatic plants and 80.66%-100% for jars without aquatic plants (Chen et al. 2009).
A new variety- serotype H-14 is particularly active against mosquito and black fly larvae. It is most active against Aedes, Culex, and Psorophora spp., and slightly less so against Anopheles. Bt H-14, which is commercially available under a number of trade names, is a proven, environmentally-nonintrusive mosquito larvicide. It is entirely safe for humans when the larvicide is used in drinking water in normal dosages. Bt. H-14 formulations tend to rapidly settle at the bottom of water containers, and frequent applications are therefore required. The toxin crystal is formed alongside the spore. Larval enzymes digest the crystal, releasing the toxin within seconds of ingestion, and larvae are killed within hours of ingesting a lethal dose (WHO, 1982). The mosquito indices of BI, CI and HI decreased gradually after application of Bti H-14 at rural areas in Thailand. It shows that the Bti is most effective in control of mosquito larval populations in water jars (water container) which is the main positive breeding site for mosquito larvae (Phan-Urai et al.
56 Table 2.8 Summary of reports on the use of Bacillus thuringiensis israelensis (Bti)
as biocontrol agents for mosquito species
No. Biocontrol agents Prey Country / Reference
1. Bacillus thuringiensis israelensis (Bti)
Ae. aegypti larvae Malaysia (Chen et al.
2009) 2. Bacillus thuringiensis
Cx. saltanesis larvae Brazil (Zequi & Lopes, 2007)
3. Bacillus thuringiensis israelensis (Bti) and Mesocyclops
Ae. aegypti larvae Thailand (Kittayapong et al. 2006)
4. Bacillus thuringiensis israelensis (Bti)
Ae. aegypti larvae Thailand (Phan-Urai et al.
1995) 5. Bacillus sphaericus strain
Cx. quinquefasciatus larvae
Thailand (Mulla et al.
6. Bacillus sphaericus Culex pipiens larvae Israel (Uspensky et al.
1998) 2.9.3 Copepoda
In Vietnam the Copepoda, Mesocyclops were successful in the control of larval Ae.
aegypti where it reduced the number of mosquito population in containers (Nam et al.
1998) and larval An. albimanus and in term of costing the use of Mesocyclops as predator is inexpensive and easy to transport (Marten et al. 1989). Marten (1990) in his study introduced Macrocyclops albidus in tire piles that contained Ae. albopictus larvae, as a results it reduced the population Ae. albopictus larvae and Mesocyclops longisetus was also used to control Ae. albopictus larvae in tires (Luciana et al. 1996).
The field trial of application of Mesocyclops species has also been done in many habitats such as tires, temporary pools, marshes, rice fields, residential roadside ditches and domestic containers. From the results different species of Cyclopoid can eliminate or effective against different types of mosquito species which are in suitable habitat. For instance Mesocyclops longisetus can effecitively eliminate mosquito larvae of Ae. aegypti in cisterns, 55-gallon drums and domestic container. They also suggest that 2 species of
57 Mesocyclops longisetus and Macrocyclops albidus could be of use to control larvae Anopheles spp. and Cx. quinquefasciatus (Marten, et al. 1994b). Cyclopoid will survive well in two conditions (i) if they get enough food supply and (ii) need proper habitat which is near vegetation with no direct sunlight (Jorge, et al. 2004; Marten, et al. 1994b). Many species of Cyclopoid have been proven as one of the biocontrol agents of mosquito (Table 2.9).
58 Table 2.9 Summary of reports on the use of Cyclopoid as biocontrol agents for
No. Biocontrol agents Prey Country / References
An. albimanus larvae Colombia (Marten et al. 1989)
2. Acanthocyclops vernalis, Diacyclops navus, Macrocyclops albidus, Mesocyclops edax,
Mesocyclops longisetus, and Mesocyclops sp. (Cyclops)
Ae. albopictus larvae New Orleans (Marten et al. 1989)
3. Mesocyclops longisetus and Macrocyclops albidus
Anopheles spp. and Cx.
New Orleans (Marten et al. 1994a)
4. Mesocyclops longisetus, Mesocyclops
Mesocyclops venezolanus and Macrocyclops albidus
Ae. aegypti larvae New Orleans (Marten et al. 1994a)
5. Mesocyclops longisetus and Macrocyclops albidus
Cx. pipiens larvae Uruguay (Maite et al.
2008) 6. Mesocyclops
Ae. aegypti larvae Vietnam (Vu et al.
1998) 7. Macrocyclops albibus
Ae. albopictus larvae New Orleans (Marten 1990b)
8. Mesocyclops thermocyclopoides (Copepoda:Cyclopoida)
Cx. quinquefasciatus and An. stephensi larvae Alternate prey – Moina
Delhi, India (Kumar &
9. Mesocyclops aspericornis Ae. aegypti larvae India (Ramanibai &
10. Mesocyclops longisetus Ae. albopictus larvae Brazil (Santos et al.
1996) 11. Macrocyclops albibus Ae. albopictus and Ae.
USA (Rey et al. 2004) 12. Mesocyclops longisetus Ae. albopictus, Ae.
triseriatus and Cx.
USA (Soumare &
Cilek , 2011)
13. Mesocyclops aspericornis, Mesocyclops
thermocyclopoides and Mesocyclops woutersi
Ae. albopictus and Ae.
Vietnam (Kay et al.
59 14. Mesocyclops brevisetosus Ae. aegypti, Cx.
quinquefaciatus, and An.
Indonesia (Yoyo et al.
2006) 15. Mesocyclops longisetus
Ae. albopictus and Cx.
USA (Soumare et al.
2004) 16. Acanthocyclops robustus,
Diacyclops uruguayensis, Macrocyclops
albidus andMesocyclops longisetus
Ae. aegypti and Cx.
Argentina (Tranchida et al. 2009)