The disease root-knot of brinjal is caused by

Options

A. Phytophthara infestans
B. Melodiaogyne incognita
C. Fusarium udum
D. Xanthomonas citiri

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the causative agent of the root-knot disease in brinjal (eggplant).

2. **Analyzing the Options**: We have four options to consider:
- **Option A: Phytophthora infestans**: This organism is known to cause late blight in potatoes, not root-knot disease in brinjal.
- **Option B: Malediogyne incognita**: This is a type of nematode known to cause root-knot disease in various plants, including brinjal.
- **Option C: Fusarium odum**: This fungus is responsible for wilt disease in pigeon pea (Cajanus cajan), not root-knot disease.
- **Option D: Xanthomonas citri**: This is a bacterium that causes citrus canker, which is unrelated to brinjal.

3. **Identifying the Correct Answer**: Based on the analysis:
- **Phytophthora infestans** is incorrect as it affects potatoes.
- **Fusarium odum** is incorrect as it affects pigeon pea.
- **Xanthomonas citri** is incorrect as it affects citrus plants.
- **Malediogyne incognita** is the correct answer as it specifically causes root-knot disease in brinjal.

4. **Conclusion**: Therefore, the disease root-knot of brinjal is caused by **Malediogyne incognita**.

### Final Answer:
The disease root-knot of brinjal is caused by **Malediogyne incognita**.

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