New federal regulations would make it harder for hemp growers to prove their plants are not marijuana, in what could be a major setback to a promising industry legalized just two years ago, farmers and state officials say.

The U.S. Department of Agriculture in October unveiled stricter standards for hemp testing than many states had allowed under pilot programs that date to 2014. Now states are scrambling to adapt, and farmers are worrying they’ll face a higher risk of having to destroy crops that test “hot” as marijuana.

“Once again, Washington, D.C., is out of touch with rural America,” said Democratic Vermont state Sen. John Rodgers, who is also a hemp farmer.

Hemp and marijuana are separated by a fine legal line: Federal law defines cannabis plants with a concentration greater than 0.3% of the psychoactive compound tetrahydrocannabinol, or THC, as illegal marijuana. Plants with a lower concentration are defined as hemp, which can be legally sold anywhere.

The interim USDA rule that states must adopt by November requires more rigorous testing within a shorter time frame than many states have required so far. It also gives farmers less wiggle room to salvage crops that grow hot, or above the 0.3% THC mark.

Last year in the 16 states that shared their data with Stateline, 4,309 acres of hemp out of more than 179,000 acres planted were destroyed because plants tested over the 0.3% limit.  [Read More @ Pew Charitable Trust]