From the Center for Investigative Reporting in PRX, this is Reveal.

I'm Al Etzin.

This week we're updating an episode from last spring.

It's about some turf battles playing out in farm country.

The first story is about a herbicide used to get rid of aggressive weeds and soybean

fields.

It's called dicamba.

And it sparked a civil war, pitting neighbor against neighbor, like these farmers in Arkansas.

Never in my 20 years of ever seen a product tear friendships apart, families apart.

Soybeans are a $40 billion business in the US.

My daddy always tell me when you're back a man in the corner and kind of get on his livelihood,

dangerous and bad things can happen on both sides.

Since last year, soybean prices have taken a beating because of the US trade war with China.

China was one of our biggest soybean customers, but now it's turning to Brazil and other countries.

American farmers are desperate for anything that can help them keep their profits up,

which is why a weed killer like dicamba is attractive.

But here's the problem.

dicamba is blamed for drifting to other fields and damaging crops on nearby farms.

State Departments of Agriculture report that dicamba hurt some 3.5 million acres in 2017.

There have been petitions, lawsuits, even a death blamed on an argument over dicamba

and some pretty heated rhetoric.

So the question is, the dicamba farmer, his dream, his American dream,

...