Oh, no doubt about that. However, if faced with extinction by a 'silver bullet' technology such as you are describing, the multi-billion dollar industry (the people at the top of it anyway) would probably commit significant resources to overcoming the technology.
If fields are burned, the narcotrafficantes suffer no loss.
We'll have the new seed, weed and bush in place, growing invisibly among the old stuff before these guys catch on.
I suppose a sign of a bad crop would be if we stopped using herbicides on it.