Which protozoans is harmful to sericulture

Options

A. Babesia
B. Monocystis
C. Nosema
D. Plasmodium

Answer

**Step-by-Step Solution:**

1. **Understanding Sericulture**:
- Sericulture refers to the cultivation of silkworms for the production of silk. It involves raising silkworms and harvesting silk fibers from their cocoons.

2. **Identifying Protozoans**:
- The question asks about protozoans that are harmful to sericulture. Protozoans are single-celled organisms that can be parasitic.

3. **Evaluating Options**:
- **Option 1: Babesia**:
- Babesia are parasites that primarily infect red blood cells in mammals and are not related to silk farming. Therefore, this option is incorrect.

- **Option 2: Monocystis**:
- Monocystis are internal parasites of certain vertebrates, not specifically harmful to silkworms or sericulture. Hence, this option is also incorrect.

- **Option 3: Nosema**:
- Nosema are microsporidian parasites that can infect silkworms and are known to cause diseases in them, making this option the correct answer.

- **Option 4: Plasmodium**:
- Plasmodium is known for causing malaria in humans and does not affect sericulture. Thus, this option is incorrect.

4. **Conclusion**:
- The protozoan that is harmful to sericulture is **Nosema**.

**Final Answer**: Nosema

---