I think we might be using different definitions of "burn." I mean burnt by radiation so it no longer photosynthesizes -- in some plants this can happen simply f

I think we might be using different definitions of "burn." I mean burnt by radiation so it no longer photosynthesizes -- in some plants this can happen simply from overexposure to sunlight. It's not necessary to turn it to ash. A machine continually damaging cotyledons in emerging seedlings would go a long way. That's part of the advantage of a continually running weed killer.