Why should biological control of pests and pathogens be preferred to the conventional use of chemical pesticides?

Explanation

The toxic chemical pesticides, which are used to kill or repel the pests, are hazardous, if not handed properly. They are costly, harmful, pollute the biosphere and create ecological inbalance. Therefore, scientists are searching for noval approaches, such as biological control of pets and pathogens, to control the insects and other pests.