Which of the following pathogen is not correctly matched with the disease it causes

Options

A. Root knot disease - Meloidogyne javanica
B. Smut of bajra - Tolysporium penicillariae
C. Covered smut of barley - Ustilago nuda
D. Late blight of potato - Phytophthora infestans

Explanation

To determine which pathogen is not correctly matched with the disease it causes, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the first pathogen and disease:**
- **Pathogen:** Malignodegain javanica
- **Disease:** Root knot disease
- **Analysis:** This pathogen is correctly matched with root knot disease, as it causes the formation of galls on the roots of infected plants.

2. **Identify the second pathogen and disease:**
- **Pathogen:** Tolysporum penicillere
- **Disease:** Smut of Bajra
- **Analysis:** This pathogen is also correctly matched with the disease, as it is known to cause significant yield losses in Bajra by replacing grains with smut sori.

3. **Identify the third pathogen and disease:**
- **Pathogen:** Estilago nuda
- **Disease:** Covered smut of barley
- **Analysis:** This is the incorrect match. The correct pathogen for the covered smut of barley is Estilago hordii, not Estilago nuda.

4. **Identify the fourth pathogen and disease:**
- **Pathogen:** Phytophthora infestans
- **Disease:** Late blight of potato
- **Analysis:** This pathogen is correctly matched with the disease, as it is well-known for causing late blight in potatoes, particularly under cool and moist conditions.

5. **Conclusion:**
- The only incorrect match is the third option, where Estilago nuda is listed as the cause of covered smut of barley. The correct pathogen should be Estilago hordii.

### Final Answer:
The pathogen that is not correctly matched with the disease it causes is **Estilago nuda** (covered smut of barley).

---