Question

Bacillus thuringiensis is used to control:
A. Bacterial pathogens
B. Fungal Pathogens
C. Nematodes
D. Insect pest

Answer 1

Hint:-Bacillus thuringiensis is a gram positive soil organism which is commonly used as biological pesticide. They generally produce a variety of cry proteins which are used on crops and are found toxic against a wide variety of insect pests. It is generally used as insecticides.

Complete Answer:-It is a species of bacteria normally that lives in soil. It makes the proteins that are toxic to some insects while non-toxic to others. One of its type which is called ‘Azawi’ can be toxic and life threatening to honeybees. Bacillus thuringiensis is normally safe for humans and is already widely used as compatible biopesticide worldwide. It has been noticed that some strains of Bacillus thuringiensis produce non-insecticidal proteins that crystallize into irregular shaped parasporal inclusions. Cry genes are high in their plasticity. This unique feature contributes to the versatility of cry toxins. It works by the mechanism as when the bacteria is consumed by the certain insects, the toxic crystal is released in the insect’s highly alkaline gut, blocking the system which protects the pest’s stomach from its own digestive juices. The stomach is penetrated and the insect dies. It is found harmless to birds, fishes and mammals including humans as mentioned above.

So the above mentioned question’s correct answer is option (D) Insect pest.

Note:- Bacillus thuringiensis is low in toxicity to people and other mammals. It has been not found with any severe effects on them but still if it may cause sickness or infection with exposure like redness of eyes, skin irritation, runny nose, goosebumps.