TCDD, a dioxin side product in hasty government manufactured Agent Orange, was the agent responsible for the biological destruction in Vietnam.
TCDD and related chemicals are nasty, terrible things. Commercial grade Agent Orange will not contain the dioxins. The herbicides themselves are no where near as toxic.
And about this nature versus manmade issue: you are damn right that nature will adapt to our efforts. That is how it works. It is a constant battle between organisms to kill each other. Every living thing, especially plants, have poisons and chemical defenses. Natural poisons are not automatically safer than synthetic poisons.
Eating an a high dose of apple seeds, for instance, can be fatal.
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