Which of the following is gregarious pest :-

Options

A. Bed bug
B. Rat
C. Cockroach
D. Locusta

Answer

To determine which of the following is a gregarious pest, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Gregarious Pests**:
- Gregarious pests are those that move and act collectively in groups, often causing significant damage to crops. They tend to swarm and can be very destructive.

2. **Analyze Each Option**:
- **Option 1: Bad Bug**:
- Bad bugs are small brownish insects that primarily feed on the blood of animals and humans. They do not exhibit gregarious behavior.
- **Conclusion**: This option is incorrect.

- **Option 2: Red Bug**:
- Without specific details, red bugs generally do not swarm in a gregarious manner like locusts. They are not known for collective behavior.
- **Conclusion**: This option is incorrect.

- **Option 3: Cockroach**:
- Cockroaches are omnivorous insects that can be found in groups, but they do not exhibit the same level of collective destructive behavior as gregarious pests. They are scavengers rather than pests that swarm to attack crops.
- **Conclusion**: This option is incorrect.

- **Option 4: Locust**:
- Locusts are well-known gregarious pests. They can form large swarms that move together and can devastate crops in their path. Their behavior of swarming is a classic example of gregariousness in pests.
- **Conclusion**: This option is correct.

3. **Final Answer**:
- The correct answer is **Option 4: Locust**.