Which of the following is incorrectly matched ?
Disease Causative organism

Options

A. Blank rot of crucifers Bacteria
B. Brown rust of wheat Fungi
C. Late blight of potato Virus
D. Red rot sugarcane Fungi

Answer

To determine which of the following disease and causative organism pairs is incorrectly matched, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Identify the first pair: Black rot and its causative organism.**
- **Disease:** Black rot
- **Causative organism:** Bacteria
- **Correctness:** Black rot of crucifers is caused by *Xanthomonas campestris*, which is indeed a bacterium.
- **Conclusion:** This pair is correctly matched.

2. **Identify the second pair: Brown rust in wheat and its causative organism.**
- **Disease:** Brown rust
- **Causative organism:** Fungi
- **Correctness:** Brown rust in wheat is caused by a fungus, specifically *Puccinia triticina*.
- **Conclusion:** This pair is correctly matched.

3. **Identify the third pair: Late blight of potato and its causative organism.**
- **Disease:** Late blight
- **Causative organism:** Virus
- **Correctness:** Late blight of potato is caused by the fungus *Phytophthora infestans*, not a virus.
- **Conclusion:** This pair is incorrectly matched.

4. **Identify the fourth pair: Red rot in sugarcane and its causative organism.**
- **Disease:** Red rot
- **Causative organism:** Fungi
- **Correctness:** Red rot in sugarcane is caused by the fungus *Glomerella tucumensis*.
- **Conclusion:** This pair is correctly matched.

### Final Answer:
The incorrectly matched pair is: **Late blight of potato - Virus** (it is caused by a fungus, *Phytophthora infestans*).

---