Ergot of rye is caused by a species of

Options

A. Claviceps
B. Phytophthora
C. Uncinula
D. Ustilago

Answer

**Step-by-Step Solution:**

1. **Identify the Disease**: The question asks about the cause of "ergot of rye." This is a known fungal disease that affects certain plants, particularly rye.

2. **Determine the Causative Agent**: Ergot is specifically caused by a fungus. The key species responsible for this disease is known as *Claviceps purpurea*.

3. **Understand the Infection Process**: The fungus *Claviceps purpurea* infects the ovaries of the host plant. It does not affect other parts of the plant, which is an important detail.

4. **Observe the Symptoms**: The infection leads to a change in color of the grains from black to purple. This is a characteristic symptom of the disease.

5. **Recognize the Structure Formed**: The fungus produces a structure called a sclerotium, which is a type of fruiting body. Within this structure, ascospores are formed, which are asexual reproductive structures.

6. **Classify the Fungus**: The genus *Claviceps* belongs to the division Ascomycetes, which is important for classification purposes.

7. **Select the Correct Option**: Based on the information, the correct answer to the question is *Claviceps purpurea*. Other options like Phytophthora, Unifunella, and Astiligo are not related to the disease ergot.

**Final Answer**: Ergot of rye is caused by a species of *Claviceps purpurea*.

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