BIOCONTROL POTENTIAL OF BACILLUS THURINGIENSIS ISOLATED FROM SOIL SAMPLES AGAINST LARVA OF MOSQUITO
ABSTRACT
A major challenge for achieving successful mosquito control is overcoming insecticide resistance. Bacillus thuringiensis which is one of the most effective biolarvacide for control of species of mosquitoes and monitoring of larval susceptibility is essential to avoid resistance development. Mosquito larvacidal activity of Bacillus thuringiensis was assessed by isolating them from ecologically different soil habitats in and around Enugu metropolis. The isolate organisms were confirmed as Bacillus thuringiensis based on biochemical characterization and microscopic observation. The larvacidal activity of Bacillus thuringiensis isolates was tested against the larval of mosquito by using the standard cup bioassay. The isolates of Bacillus thuringiensis showed a significant level of variation in their larvacidal activity.
TABLE OF CONTENT
Title Page
Certification
Dedication
Acknowledgement
Abstract
Table Of Contents
List Of Tables
CHAPTER ONE:Â
1.0 INTRODUCTIONÂ
1.1 Crystal Composition And Morphology
1.2 General Characteristics Of Bacillus Thuringlensis
1.3 Classification Of Bacillus Thuringiensis Subspecies
1.4 Ecology And Prevalence Of Bacillus Thuringrensis
1.5 Other Pathogenic Factors Of Bacillus Thuringiensis
1.6 Morphological Properties Of Bacillus Thuringiensis
CHAPTER TWO:Â
2.0 LITERATURE REVIEW
2.1 Mode Of Action On Target Organism
2.2 Mechanism Of Action Of Bacillus Thuringensis Formulation
2.3 General Application Of Bacillus Thuringiensis
CHAPTER THREE:Â
3.0 MATERIAL AND METHODÂ
3.1 Soil Sample Collection
3.2 Isolation Of Bacillus Thuringiensis
3.3 Isolation Of Bacillus Thuringiensis From Soil
3.4 Sample Staining
3.5 Biochemical Identification
3.6 Materials And Method Of Bacillus Theringiensis Against Mosquito Lava
3.7 Catalase Test
3.8 Oxidase Enzyme Activity
3.9 Sugar Test
3.10 Methyl Red Test
3.11 Indole Test
CHAPTER FOUR:Â
4.0 RESULT OF SAMPLE COLLECTION AND ISOLATION
4.1 Colony Morphology Of Bacillus Isolates
4.2 Biochemical Test
4.3 Bioassay
CHAPTER FIVE:Â
5.0 DISCUSSIONÂ
5.1 Conclusion
5.2 Recommendations
5.3 References
Appendix 1
Appendix 2
CHAPTER ONE
INTRODUCTIONÂ
Bacillus thuringrensis (Bt) is a well known and widely studied bacterium which is known for its use in pest management. Today it is the most successful commercial xenobiotic with its worldwide application when compared with the chemical pesticides; Bacillus thuringiensis has the advantages of being biologically degradable, selectively active on pests and less likely to cause resistance. Safety of Bacillus thuringiensis formulations for humans, beneficial animals and plants explains the replacement of chemical pesticides in many countries with these environmentally friendly pest control agents.
Bacillus thuringiensis was first isolated by the Japanese Scientist Ishiwata (1901) from skilkworm larvae, bombyxmori, exhibiting sotto disease. After 10 years, Berliner (1911) isolated the square gram (+) positive, spore-forming, rod shaped soil bacterium from disease flour moth larvae, Anngasta Kachmiccalla, in the Thuringia region of the Germany and named it as Bacillus thuringiensis.
In the early 1930s Bacillus thuringiensis was used against Ostrinianubilis, the European corn borer. The first commercial product was available in 1938 in France, with the trade name sporeine (Weiser, 1986). It was Bacillus thuringiensis subspecies Kurstaki that was used for the control of the insect (Lepidopteran) pests in agriculture and forestry (Luthy & Ebersold, 1981). New commercial products arrived in 1980s after the discovering of subspecies thuringiensis opened the gate for black fly and mosquito larvae control.
Like all organisms, insect are susceptible to infection by pathogenic microorganisms, many of these infections agents have a narrow host range and therefore, do not cause uncontrolled destruction of beneficial insects and are not toxic to vertebrates. Bacillus thuringiensis is a major microorganism, which shows entamopathogenic activity (Glazer & Nikaido, 1995, Schnepf, et al. 1998) which forms parasporal crystals during the stationary phase of its growth cycle.
Most Bacillus thuringiensis preparations available on the market contain spores with parasporal inclusion bodies composed of δ – endotoxins. In commercial production, the crystals and spores obtained from fermentation are concentrated and formulated for spray on application according to conventional Agriculture practices (Baum, Kakefuda, & Gawron-Burke, 1996). There are many strains of Bacillus thuringiensis having insecticidal activity against insect order (eg Lepidoptera, Diptera, Homoptera, Mollaphage, Coloptera). Only a few of them have been commercially developed.
