Which one of the following organsims is not used as biocontrol agent ?

Options

A. Bacillus sphaericus
B. Trichoderma viride
C. Bacillus thuringenesis
D. Bacillus subtilis

Answer

To determine which organism is not used as a biocontrol agent, we will analyze each option provided in the question step by step.

### Step 1: Analyze Bacillus sepharicus
- **Function**: Bacillus sepharicus is known to control mosquito larvae.
- **Conclusion**: Since it is used as a biocontrol agent, this option is not the answer.

### Step 2: Analyze Trichoderma veridae
- **Function**: Trichoderma veridae is used as a biofungicide to prevent the growth of fungi.
- **Conclusion**: This organism is also used as a biocontrol agent, so this option is not the answer.

### Step 3: Analyze Bacillus thuringiensis
- **Function**: Bacillus thuringiensis acts as an insecticide, controlling insect herbivores on plants.
- **Conclusion**: This organism is utilized as a biocontrol agent, so this option is not the answer.

### Step 4: Analyze Bacillus subtilis
- **Function**: Bacillus subtilis is a gram-positive bacterium used primarily in fermentation processes and is consumed as a prebiotic. It is not known for biocontrol purposes.
- **Conclusion**: Since Bacillus subtilis is not used as a biocontrol agent, this is the correct answer.

### Final Answer
The organism that is not used as a biocontrol agent is **Bacillus subtilis**.

---