Which is wrong combination of disease and its casual organism in context of silkworm?

Options

A. Pebrine - Nosema bombycis
B. Muscardine - Spicaria
C. Muscardine - Botrytis
D. Flacherie - Nuclear polyhedral virus

Answer

To solve the question regarding the wrong combination of disease and its causal organism in the context of silkworm, we will analyze each provided combination step by step.

### Step 1: Identify the combinations
We have several combinations of diseases and their causal organisms related to silkworms. The combinations include:
1. Pabrin - Nauzema bombicis
2. Muscadine - Aspicaria
3. Muscadine - Botrytis
4. Flesh tree - Nuclear polyhedral virus

### Step 2: Analyze each combination
1. **Pabrin - Nauzema bombicis**:
- Nauzema bombicis is a protozoan that affects silkworms. This combination is correct as it accurately describes the disease and its causal organism.

2. **Muscadine - Aspicaria**:
- Aspicaria is a fungus that can cause diseases in silkworms, making this combination correct.

3. **Muscadine - Botrytis**:
- Botrytis is another fungus, commonly known as white mold, which can affect silkworms. This combination is also correct.

4. **Flesh tree - Nuclear polyhedral virus**:
- The nuclear polyhedral virus is not the correct causal organism for the disease affecting flesh tree. Instead, flesh tree is harmed by a bacterium known as streptococci bacillus. Therefore, this combination is incorrect.

### Step 3: Conclusion
The wrong combination of disease and its causal organism in the context of silkworm is:
- **Flesh tree - Nuclear polyhedral virus**