A pesticide kills 95% of a pest population. what will be the result of the continued application of this pesticide?

A pesticide kills 95% of a pest population. This means that 5% of the pests were either developed resistance to it or escaped death due to poisoning. If the pests were able to develop resistance to the pesticides then the continued application of the pesticide will be of no use, as these surviving pests will eventually form a population of pests that will be resistant to the pesticide and thus will harm the crops.