Which of the following statement is incorrect with respect to sericulture -

Options

A. Silk glands are modified salivary gland of caterpillar larva.
B. `5^(th)` instar forms cocoon.
C. Silk consists of sericin and fibrinogen protein.
D. Reeling is the process of removal of fibre from killed cocoon

Answer

**Step-by-Step Solution:**

1. **Understanding Sericulture**: Begin by defining sericulture, which is the practice of breeding silkworms for the production of silk. The primary species used in sericulture is *Bombyx mori*.

2. **Analyzing the Statements**: Examine each statement provided in the question to identify which one is incorrect.

- **Statement 1**: "Silk glands are the modified salivary glands of the caterpillar larva."
- This statement is **correct**. The silk glands in silkworms are indeed modified salivary glands.

- **Statement 2**: "The fifth instar from the cocoon."
- This statement is also **correct**. The fifth instar stage is when the silkworm prepares to spin its cocoon, shedding its hair and forming a smooth skin.

- **Statement 3**: "Silk consists of sericin and fibrinogen protein."
- This statement is **incorrect**. Silk is made up of sericin and fibrin **protein**, not fibrinogen. Fibrinogen is a precursor to fibrin, which is not present in silk.

- **Statement 4**: "Reeling is the process of removal of fiber from the killed cocoon."
- This statement is **correct**. Reeling refers to the process of unwinding silk fibers from the cocoon, which typically involves killing the pupa inside.

3. **Identifying the Incorrect Statement**: After analyzing all statements, it is clear that the third statement is incorrect because it mentions "fibrinogen" instead of "fibrin."

4. **Conclusion**: The answer to the question is that the incorrect statement with respect to sericulture is the third one.

**Final Answer**: The incorrect statement is: "Silk consists of sericin and fibrinogen protein."

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