This already exists! There's a company called Carbon Robotics that has a prototype of a robot that eliminates individual weeds with a lazer: https://www.youtube.com/watch?v=_2s-0wgQWXM
I'm also looking forward to this technology being widely available and helping solve the issue of herbicide run-off, and later additionally the same for pesticides and fertilization.
I'm also looking forward to this technology being widely available and helping solve the issue of herbicide run-off, and later additionally the same for pesticides and fertilization.