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An assessment of microbial formulations of Bacillus
thuringiensis and Bacillus sphaericus for the
management of mosquito larvae causing malaria and filariasis
Felix Jerry Akpabey* and Michael Ocran
Council for Scientific and Industrial Research (CSIR)-Water
Research Institute (WRI), Environmental Biology and Health
Division, P. O. Box AH 38, Achimota, Accra, Ghana.
*Corresponding author.
E-mail: ffelix39@yahoo.co.uk. Tel: 233 21 775351/2.
Fax: 233
21 777170.
Accepted 25 June, 2010 |
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Two
biological formulations of
microbial agents Bacillus thuringiensis and
Bacillus sphaericus known by their trade names as
Vectobac 12 AS and VectoLex CG (corn cob) granules,
respectively were obtained from Abbott Laboratories of North
Chicago, USA. The B. sphaericus formulation was used
in trials against Culex mosquito larvae in choked
gutters at Labadi, Ashaiman and Nungua in the Greater Accra
Region, whilst the B. thuringiensis formulation was
used against Anopheles sp. in paddy rice fields at
Akuse. The results indicate a 99 to 100% mortality of all
larvae with both B. thuringiensis and B.
sphaericus for 5 to 16 days after application at their
breeding sites. Both the products tested are effective to
kill the target larvae at 24 to 48 h even at low
concentrations. The formulations act on filter-feeding and
grazing aquatic insect larvae after ingestion. They do not
affect non-target aquatic insects and are harmless to
humans. In this report, mosquito control using bio-larvicides
has been proposed as one reliable method of reducing disease
prevalence by killing the larvae at their breeding sites
thus interrupting the life cycle at the larval stage.
Key words: Mosquito, larvae, formulations, breeding
site. |
