Question

A microbial biocontrol agent which control butterfly caterpillars in plants is -

• A. Bacillus thuringiensis
• B. Streptococcus sps.
• C. Saccharomyces cerevisiae
• D. Trichoderma polysperum

Hint:

The abbreviation {Bt} (from {Bacillus thuringiensis}) is synonymous with microbial control of caterpillars. Bt corn and Bt cotton are famous examples of GMOs that produce this bacterial toxin to protect themselves from pests.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question asks to identify a microbe that acts as a biological control agent specifically against the larvae (caterpillars) of butterflies and moths.
Step 2: Detailed Explanation:
Bacillus thuringiensis (Bt): This is a soil-dwelling bacterium that is widely used as a biological pesticide. It produces crystalline proteins (Cry proteins) that are toxic to specific insect orders, most notably Lepidoptera (butterflies and moths). When a caterpillar ingests the Bt toxin, it becomes paralyzed, stops feeding, and dies.
Streptococcus sps.: A genus of bacteria known for various roles, including some species that are part of the normal human flora and others that are significant human pathogens (e.g., causing strep throat). They are not used as insect biocontrol agents.
Saccharomyces cerevisiae: This is brewer's or baker's yeast, a fungus used extensively in the food and beverage industry. It has no insecticidal properties.
Trichoderma polysperum: A species of fungus belonging to the genus Trichoderma. Many Trichoderma species are used as biocontrol agents against fungal plant pathogens, but not against insects.
Step 3: Final Answer:
Bacillus thuringiensis is the microbial biocontrol agent used to control butterfly caterpillars.