One of the major difficulties in the biological control of insect pests is the

Options

A. practical difficulty of introducing the predator to specific areas
B. method is less effective as compared with the use of insecticides
C. predator does not always survive when transferred to a new environment
D. the predator develops a preference to other diets and may itself become a pest

Explanation

**Step-by-Step Solution:**

1. **Understanding Biological Control**: Biological control refers to the use of natural enemies (predators, parasitoids, and pathogens) to manage pest populations. This method is part of integrated pest management (IPM) programs, which aim to reduce reliance on chemical pesticides.

2. **Identifying the Challenges**: One of the major difficulties in biological control is ensuring that the introduced biological control agents (predators or parasitoids) can survive and thrive in the new environment.

3. **Evaluating the Options**: The question provides several options regarding the difficulties in biological control:
- A) Practical difficulty of introducing the predator to the specific area.
- B) Method is less effective compared to the use of insecticides.
- C) Predator does not always survive when transferred to a new environment.
- D) Predator develops a preference for another diet and may itself become a pest.

4. **Analyzing Each Option**:
- Option A discusses the practical difficulties of introduction, which can be a challenge but is not the most significant issue.
- Option B states that biological control is less effective than insecticides, which is subjective and not universally true.
- Option C highlights the survival of the predator in a new environment, which is indeed a significant concern.
- Option D mentions that the predator may develop preferences for other diets and become a pest itself, which is a notable drawback in biological control.

5. **Selecting the Correct Answer**: After analyzing the options, the most significant difficulty in biological control is that the predator develops a preference for other diets and may itself become a pest. This can disrupt the ecological balance and lead to unintended consequences.

6. **Conclusion**: Therefore, the correct answer to the question is option D: "Predator develops a preference for other diets and may itself become a pest."

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