A comparative study of local and standard strains of Bacillus Sphaericus
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Date
1992-09-28
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Abstract
It is now seldom feasible to achieve satisfactory suppression of disease through vector control programmes, relying solely on the use of chemicals, and the use of biological control agents provides a viable option in vector control strategies, because of the relative safety of most biological control agents to mammals and non-target biota.
Out of the many different types of organisms being evaluated for vector control potential, bacteria of the genus Bacillus have proved most promising. Two insecticidal species - Bacillus thuringiensis var. israelensis (H - 14) and Bacillus sphaericus - possess considerable larvicidal activity on blackflies and Culex mosquitoes respectively (TDR/BCV/SWG-7/84).
Lymphatic filariasis is a parasitic disease caused by the filarioid nematode called Wuchereria bancrofti. In urban areas, the mosquito - Culex guinquefasciatus - is known to be the main vector of this disease (Ukoli, 1984).
Culex mosquitoes are known to breed in polluted environments resulting from growth in the size of towns and poor sanitation (Nicolas et al, 1987). Kumasi, a city in the Ashanti Region of Ghana abounds in Culex breeding sites.
Two local strains of Bacillus sphaericus codenãmed OSS and AL proved ineffective in killing laboratory - bred larvae of two species of Culex mosquitoes collected from three slum suburbs of Kumasi. Two well-known strains of B. sphaericus - 2362 (SPU 88) and 1593 (RB 80) - imported from the Institut Pasteur, Paris, France, proved very effective in killing larvae of the t species of Culex. Crosses of the local and imported bacteria strains codenamed 0/s. O/R, A/S and A/R proved effective in killing larvae of one species of Culex mosquito.
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A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirement for the award of the Degree of Master of Philosophy in Biological Sciences, 1992