We've kinda been doing that for a while, see https://en.wikipedia.org/wiki/Biopesticide https://en.wikipedia.org/wiki/Biopesticide More mechanical contraptions

We've kinda been doing that for a while, see https://en.wikipedia.org/wiki/Biopesticide https://en.wikipedia.org/wiki/Biopesticide More mechanical contraptions also have a long history, and do actually include lasers: https://en.wikipedia.org/wiki/Bird_scarer#Lasers https://en.wikipedia.org/wiki/Bird_scarer#Lasers But most pests are rather microscopic. I doubt we will ever construct silicon/metal hardware better able to operate at the level of, say, spores than the biological systems that are natural to that environment.