How about shooting flying insects in mid air...........Here is idea.

Here is Smart phone app which assist farmer for selecting herbicides based on their efficacy on particular weed.

Here is what we are trying to to build... A computer vision based smart spray system.

Better use arduino that will give flexibility to work around. more info at <a href="https://modernfarmer.com/2013/05/farm-geeks-learning-to-love-the-circuit-board/" target="_blank" rel="nofollow noopener noreferrer">Farm Geeks: Learning to Love the Circuit Board - Modern Farmer</a>