Potato leaf roll and Papaya leaf curl are due to

Options

A. mycoplasma
B. virus
C. bacteria
D. viroids

Answer

**Step-by-Step Solution:**

1. **Identify the Diseases**: The question mentions two specific plant diseases: Potato leaf roll and Papaya leaf curl.

2. **Research the Causative Agents**: To determine what causes these diseases, we need to look into the known pathogens associated with them.

3. **Potato Leaf Roll**: This disease is specifically caused by a pathogen known as the Potato Leaf Roll Virus (PLRV).

4. **Papaya Leaf Curl**: Similarly, the Papaya Leaf Curl is also caused by a virus, specifically the Papaya Leaf Curl Virus.

5. **Classification of Pathogens**: The options provided are mycoplasma, virus, bacteria, and viroids. Since both diseases are caused by viruses, we can eliminate the other options.

6. **Conclusion**: Based on the information gathered, both Potato leaf roll and Papaya leaf curl are caused by viruses. Therefore, the correct answer is option B: virus.

**Final Answer**: Potato leaf roll and Papaya leaf curl are due to **virus** (Option B).

---