Select the incorrect statement

Options

A. Dragonflies are useful to get rid of mosquitoes
B. Trichoderma species are effective biocontrol agents of several fungal pathogens
C. The use of biocontrol measures will greatly reduce our dependence on toxic chemicals
D. Nucleopolyhedro virus is excellent candidate for narrow spectrum insecticidal applications

Answer

To solve the question of selecting the incorrect statement, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze Option 1**:
- Statement: "Dragonflies are useful to get rid of mosquitoes."
- Evaluation: This statement is correct. Dragonflies are known to prey on mosquitoes and other small insects, making them beneficial for controlling mosquito populations.

2. **Analyze Option 2**:
- Statement: "Trichoderma species are effective biocontrol agents of several fungal pathogens."
- Evaluation: This statement is incorrect. Trichoderma species are primarily effective against plant pathogens, not specifically fungal pathogens. They are used in biocontrol to protect plants from various diseases caused by pathogens.

3. **Analyze Option 3**:
- Statement: "The use of biocontrol measures will greatly reduce our dependence on toxic chemicals."
- Evaluation: This statement is correct. Biocontrol measures, such as the use of natural predators or biopesticides, can reduce the need for synthetic pesticides, thus decreasing reliance on toxic chemicals.

4. **Analyze Option 4**:
- Statement: "Nuclear polyhedrosis virus is an excellent candidate for narrow-spectrum insecticide application."
- Evaluation: This statement is correct. Nuclear polyhedrosis virus specifically targets certain insect species, making it a narrow-spectrum insecticide that does not harm all insects.

### Conclusion:
After evaluating all the statements, the incorrect statement is **Option 2**: "Trichoderma species are effective biocontrol agents of several fungal pathogens."