Picloram, which was developed in the 1960s, was one of many herbicides used in the "agents" the US Military used to clear forest during the Vietnam War. It works by disrupting the way plant hormones normally function, and can persist in the soil for years.

You would think they would have figured out a better solution rather than pesticide usage by now.

I'm so glad they test before they go ahead and use these chemicals /s (they did but obviously not well enough?)