"Americans may think of the disease that destroyed Ireland’s potato crops, late blight, as a European phenomenon, but its devastations actually started with them. The origin of the fungal organism responsible, Phytophthora infestans, has been traced to a valley in the highlands of central Mexico, and the first recorded instances of the disease are in the United States, with the sudden and mysterious destruction of potato crops around Philadelphia and New York in early 1843. Within months, winds spread the rapidly reproducing airborne spores of the disease, and by 1845 it had destroyed potato crops from Illinois east to Nova Scotia, and from Virginia north to Ontario.
Not since the 1840s have we seen anything like this, they declared as the Bank of England stepped in last year to save the Northern Rock bank from a collapse caused by the subprime mortgage debacle — another American-born infection. At least our potatoes are safe." (Thanks D.)
The potato famine and subprime mortgages. Read all about it.