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: Concept Summary:
The question requires identification of a microbial biological control agent effective against butterfly and moth larvae (caterpillars).
Step 2: Detailed Explanation:
Bacillus thuringiensis (Bt): This common soil bacterium functions as a biological pesticide. It produces Cry proteins, toxic to certain insect orders, especially Lepidoptera (butterflies and moths). Upon ingestion of the Bt toxin, caterpillars are paralyzed, cease feeding, and die.
Streptococcus sps.: This bacterial genus includes species that are normal human flora and others that are human pathogens (e.g., strep throat). They are not used for insect biocontrol.
Saccharomyces cerevisiae: Commonly known as brewer's or baker's yeast, this fungus is used in the food and beverage industry and lacks insecticidal properties.
Trichoderma polysperum: This fungus, belonging to the genus Trichoderma, and other Trichoderma species, are biocontrol agents against fungal plant pathogens, not insects.
Step 3: Conclusion:
Bacillus thuringiensis serves as the microbial biocontrol agent for butterfly caterpillars.