yeah I agree with all of that. based on the type of damage found to the plants, some sort of overhead beam weapon where the patterns are programmed ahead of time a la 3D printing is likely. could indeed be testing of military tech.

I mentioned lasers before but if it's possible to do it with a plasma gun, I think that would actually be the best candidate, if it is possible to control to a fine precision the amount of crop the plasma would vaporize upon contact. Maybe hidden by an artificial cloud. So someone walking by might look up and see the surreal sight of what looks like a cloud shooting off ball lightning at a crop field.