Question

What is meant by the term bio-pesticide? Name and explain the mode of action of a popular bio-pesticide.

Answer 1

Biopesticide- Definition:

Biopesticides are the pesticides whose origin is from the biological source rather than the chemically manufactured pesticides from the factories.

Advantages of biopesticides:

• Biopesticides are specific for their target insects.
• They do not cause pollution.
• They do not affect the growth of plants.
• Part 1: Bt toxin is the most popular bio pesticide. It is a crystal protein having insecticidal properties produced by the bacterium Bacillus thuringiensis.

Action of Bt toxin:

• Bacillus thuringiensis in the spore stage, forms intercellular crystalline proteins that contain insecticidal proteins called the delta endotoxins (cry proteins).
• The endotoxin that accumulates in bacteria is in an inactive form (protoxin).
• It gets activated at an alkaline pH in the gut of the insects due to the solubilisation of the crystal proteins.
• This active toxin generates pores in the epithelium of the midgut of the insects which results in the swelling of cells followed by lysis.
• The insect is unable to feed and consequently starves to death.