Which one of the following disease is not caused by fungi ?

Options

A. Red rot of sugarcan
B. Black rot of crucifers
C. Brown rust of wheat
D. Late blight of potato

Answer

To determine which disease is not caused by fungi, we will analyze each option given in the question:

1. **Red rot of sugarcane**: This disease is caused by the fungus *Colletotrichum falcatum*, which is a deuteromycete. Therefore, this disease is caused by fungi.

2. **Black rot of crucifer**: This disease is caused by the bacterium *Xanthomonas campestris*. Since this is caused by bacteria, it is the disease that is not caused by fungi.

3. **Brown rust of wheat**: This disease is caused by the fungus *Puccinia*, which is a basidiomycete. Thus, this disease is caused by fungi.

4. **Late blight of potato**: This disease is caused by *Phytophthora infestans*, which is classified as an oomycete (a type of lower fungi). Therefore, this disease is also caused by fungi.

Based on the analysis, the disease that is not caused by fungi is **Black rot of crucifer**.

### Final Answer:
**Black rot of crucifer** (caused by *Xanthomonas campestris*, a bacterium).

---