Insects are never gonna be killed mechanically, those are too small and too many in count. Modern trend is to use biological controll: you "plant" organism that eat them or eat their eggs.
Just to expand on my comment, biological control is quite varied, but the main theme is selectivity: you don't want to destroy all the insects or butterflies, just those who do harm to your produce.
So you basically have couple of forms, either some microbes, viruses or some form of insects that eat on just one type of insect or of insect class. Another main form is pheromone confusion thingies: you put them in your orchard/vineyard/market garden and it make hard for males of your target pest to find female and procreate.
Certain pests (mainly large beetles or their larvae) used to be controlled by removing them manually - it's more expensive than pesticides, but it was feasible (and worth it!) to do it simply by bunch of people going over the crops. This means that they could be controlled mechanically in the future.
So you basically have couple of forms, either some microbes, viruses or some form of insects that eat on just one type of insect or of insect class. Another main form is pheromone confusion thingies: you put them in your orchard/vineyard/market garden and it make hard for males of your target pest to find female and procreate.