Reasons why the use of chemical fertilizers is not desirable:

a) Chemical methods can kill all insects:
- Chemical fertilizers often contain pesticides that are designed to kill insects.
- While this may seem beneficial in terms of pest control, it can have negative effects on the ecosystem.
- Insects play important roles in pollination, decomposition, and maintaining ecological balance.
- Killing all insects can disrupt these processes and lead to imbalances in the ecosystem.

b) Kills only harmful insects pests:
- Chemical fertilizers are often not selective in their action and can harm beneficial insects as well.
- Beneficial insects, such as pollinators and predators of pests, are important for maintaining a healthy ecosystem.
- Killing only harmful insects can disrupt the natural balance and lead to outbreaks of pests that were previously kept in check by beneficial insects.

c) Chemicals try to completely eradicate the pathogen:
- Chemical fertilizers often aim to completely eradicate pathogens, such as bacteria or fungi, that cause plant diseases.
- However, complete eradication is often not feasible and can lead to the development of resistant strains.
- Continuous use of chemical fertilizers can result in the evolution of resistant pathogens, making them less effective over time.
- Moreover, the use of chemical fertilizers can also harm beneficial microorganisms in the soil, which are important for nutrient cycling and plant health.

d) Biocontrol methods are non-specific:
- Biocontrol methods involve the use of natural enemies, such as predators or parasites, to control pests.
- Unlike chemical fertilizers, biocontrol methods are often non-specific and target a range of pests.
- This can be beneficial as it reduces the risk of developing resistance and maintains a more balanced ecosystem.
- Biocontrol methods also have the advantage of being more sustainable and environmentally friendly compared to chemical fertilizers.

In conclusion, the use of chemical fertilizers is not desirable due to their negative impacts on insects, including beneficial ones, the potential development of resistance in pathogens, and their non-specific nature. Biocontrol methods offer a more sustainable and environmentally friendly alternative for pest and disease control in agriculture.

And also it kills the usefull microbed