TIL: Back in the 1900s, the U.S. federal government banned growing black currants (!), because they believed that as a carrier of rust fungi, it could potentially cause serious damage to forestry (aka logging).

In 1966, the ban stopped being federal, and each state got the ability to decide the ban question independently. But nobody even thought to lift it.

For example, in New York, after years of effort by farmers, the ban was only lifted in 2003. However, in many states, growing black currants is still prohibited.