A common biocontrol agent for the control of plant diseases is –

Options

A. Baculovirus
B. Bacillus thuringiensis
C. Glomus
D. Trichoderma

Answer

**Step-by-Step Solution:**

1. **Understanding Biocontrol Agents**: Biocontrol agents are organisms used to control pests and diseases in plants. They can be other insects, fungi, or bacteria that help reduce the population of harmful pests without the use of synthetic pesticides.

2. **Identifying Common Biocontrol Agents**: The question asks for a common biocontrol agent for controlling plant diseases. The options provided are Bacular Virus, Bacillus Thuringiensis, Glomus, and Trichoderma.

3. **Evaluating Each Option**:
- **Bacular Virus**: This virus is known to infect and kill certain insects, making it a biocontrol agent. However, it is not the most commonly used biocontrol agent.
- **Bacillus Thuringiensis (Bt)**: This bacterium is used in genetically modified crops like Bt cotton. While effective against certain pests, it requires genetic modification, making it less common in traditional biocontrol practices.
- **Glomus**: This is a genus of fungi that forms symbiotic relationships with plant roots, particularly in legumes. While it has beneficial effects on plant health, it is not primarily used as a biocontrol agent against pests.
- **Trichoderma**: This is a genus of fungi that acts as a biocontrol agent by attacking pathogens that harm plants. It enhances plant growth and helps in nitrogen fixation without requiring genetic modification.

4. **Conclusion**: After evaluating all options, Trichoderma is identified as the most common biocontrol agent for controlling plant diseases due to its effectiveness and natural occurrence.

**Final Answer**: The common biocontrol agent for the control of plant diseases is **Trichoderma**.

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