Powdery mildew of Pea is caused by

Options

A. Puccinia
B. Erysiphe
C. Ustilago
D. Alternaria

Answer

**Step-by-Step Solution:**

1. **Identify the Disease**: The question asks about the causative agent of powdery mildew in pea plants. Powdery mildew is a fungal disease characterized by a white, powdery growth on the leaves and stems of plants.

2. **Understand the Options**: The options provided include various fungi. We need to evaluate each option to determine which one is responsible for causing powdery mildew in peas.

3. **Evaluate Each Fungus**:
- **Paxinia**: This genus belongs to the Basidiomycetes and is known for causing rust diseases in plants, such as black rust of wheat. Therefore, it is not associated with powdery mildew.
- **Erysiphe**: This genus is known to produce powdery mildew and belongs to the Ascomycetes. Specifically, for pea plants, the species Erysiphe polygoni is responsible for the powdery mildew disease.
- **Ustilago**: This genus also belongs to the Basidiomycetes and is known for causing smut diseases, such as loose smut of wheat. It is not related to powdery mildew.
- **Alternaria**: This genus is known for causing early blight in plants like potatoes and tomatoes, but it is not associated with powdery mildew.

4. **Conclusion**: Based on the evaluation, the correct answer is **Erysiphe polygoni**, which is the causative organism for powdery mildew in pea plants.

5. **Final Answer**: The powdery mildew of pea is caused by **Erysiphe polygoni**.

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