Which of the following is correct match ?
`{:(,"Disease","Pathogen"),((a),"wilt disease","Synchytrium"),((b),"Citrus canker","Xanthomonas"),((c ),"Red rot of sugarane","Ustilago"),((d),"Powdery mildew","Fusarium"):}`

Explanation

To solve the question regarding the correct match between diseases and their pathogens, we will analyze each option provided:

### Step-by-Step Solution:

1. **Analyze Option (a): Wilt Disease - Synchytrium**
- Wilt disease is not caused by Synchytrium. Synchytrium is known for causing false rust or wart diseases in plants. Therefore, this match is incorrect.

2. **Analyze Option (b): Citrus Canker - Xanthomonas**
- Citrus canker is indeed caused by Xanthomonas, which is a type of bacteria. This pathogen affects citrus plants like lime, lemon, and orange, causing lesions on leaves, fruits, and stems. This match is correct.

3. **Analyze Option (c): Red Rot of Sugarcane - Ustilago**
- Red rot of sugarcane is not caused by Ustilago. It is actually caused by a fungus known as Colletotrichum. Thus, this match is incorrect.

4. **Analyze Option (d): Powdery Mildew - Fusarium**
- Powdery mildew is caused by a different fungus called Podosphaera, not Fusarium. Fusarium is known for causing various diseases in plants and humans, but not powdery mildew. Therefore, this match is incorrect.

### Conclusion:
The only correct match from the options provided is:
- **(b) Citrus Canker - Xanthomonas**

### Final Answer:
The correct match is option (b) Citrus canker - Xanthomonas.

---