In 1950, a newly independent India was running low on food. India requested the US for help.
It wasn't provided immediately. After much debate in the US congress on why they should help India, Truman signed the India food relief act to provide India with $190 million of assistance to help it buy US wheat.
But that US wheat came with a weed. The weed known as Parthenium or also called "Congress grass." This weed destroyed any plant around it. Till today, India has not been able to get rid of this weed.
Some 35 million hectares of arable Indian farmland has been laid waste by this weed. Including, and as far as, Andaman & Nicobar Islands.
This weed is one of the biggest causes of losses for Indian agriculture and productivity. American experts still say it came into India "accidentally."