Mycorrhiza does not help the host plant in

Options

A. enhancing its phosphorus uptake capacity
B. increasing its tolerance to drought
C. enhancing its resistance to root pathogens
D. increasing its resistance to insects

Answer

### Step-by-Step Solution:

1. **Understanding Mycorrhizae**:
- Mycorrhizae are symbiotic associations between fungi and plant roots. The plant provides organic compounds (like sugars) to the fungus, while the fungus supplies essential nutrients (such as nitrogen and phosphorus) to the plant.

2. **Evaluating the Options**:
- **Option A: Enhancing phosphorus uptake capacity**: Mycorrhizae significantly increase the plant's ability to absorb phosphorus from the soil. This option is correct.
- **Option B: Increasing tolerance to drought**: Mycorrhizae help plants access more water and nutrients, especially in drought conditions, making this option correct.
- **Option C: Enhancing resistance to root pathogens**: Mycorrhizae can improve a plant's resistance to root pathogens by providing a protective barrier and enhancing overall plant health. This option is also correct.
- **Option D: Increasing resistance to insects**: Mycorrhizae do not have a direct role in increasing a plant's resistance to insect pests. This option is incorrect.

3. **Conclusion**:
- Since mycorrhizae do not help the host plant in increasing its resistance to insects, the correct answer is **Option D**.