In plants , mosaic formation and yellowing of plant parts are the symptoms of ………

Options

A. bacterial diseases
B. mycoplasmal diseases
C. viral diseases
D. fungal diseases

Answer

To solve the question regarding the symptoms of mosaic formation and yellowing of plant parts, we can follow these steps:

### Step 1: Identify the Symptoms
The symptoms mentioned are:
- Mosaic formation
- Yellowing of plant parts

### Step 2: Analyze Possible Causes
We need to consider the possible causes of these symptoms, which include:
- Bacterial diseases
- Mycoplasmal diseases
- Viral diseases
- Fungal diseases

### Step 3: Relate Symptoms to Diseases
Among the listed options, we need to determine which type of disease is most commonly associated with mosaic formation and yellowing:
- **Bacterial diseases**: These often cause wilting or rot but not typically mosaic patterns.
- **Mycoplasmal diseases**: These can cause yellowing but are less commonly associated with mosaic patterns.
- **Viral diseases**: These are well-known for causing mosaic patterns and yellowing in leaves. For instance, the Cucumber Mosaic Virus and Tobacco Mosaic Virus are classic examples.
- **Fungal diseases**: These usually lead to spots or blights rather than mosaic patterns.

### Step 4: Conclusion
Based on the analysis, the symptoms of mosaic formation and yellowing of plant parts are indicative of **viral diseases**.

### Final Answer
The correct answer is **viral diseases**.

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