Question

Bt cotton is resistant to pest, such as lepidopteran, dipterans and coleopterans. Is Bt cotton also resistant to other pests as well?

Answer 1

Bt cotton :

• Bt cotton is a genetically modified plant. It contains the cry gene from the Bacillus thuringiensis.
• The cry protein (delta endotoxin) obtained from the cry gene is a protoxin and has insecticidal properties.
• Delta endotoxin gets activated in the alkaline environment of the insect gut and causes perforations in the epithelial lining of the stomach.
• This shows that it is toxic only to the biting and chewing insects. Hence, the larvae of lepidoptera, diptera and coleoptera are affected by it.
• The sucking insects such as thrips and aphids are not affected as the phloem sap is devoid of the toxin.
• Hence, Bt cotton is not resistant to pests other than lepidopterans, dipterans and coleopterans.