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Bacillus thuringiensis (Bt) is a Gram-positive bacterium naturally found in soil, water and grain dust,
and can be cultivated in liquid, solid and semi-solid media. The objective of this work was to test the
effect of Bt toxin against onsects and mosquitoes. An Infected cotton leaves were used for the isolation of
Bt by serial dilution. It is incubated for 1 to 2 days for better growth then this culture is used for staining
for the isolation of pure species of BT. Brown, smooth small Rod shaped gram positive bacilli colonies
are isolated. After isolation these colonies are subjected to the extraction process for crystal protein
extraction. This protein is extracted by repeated centrifugation and then it is purified and used as an
insecticidal. When this protein is applied to Insects and mosquitoes it resulted in their death.
Key words: Bacillus thuringiensis, gram positive, Biopesticides