“It would be very easy to disrupt/eliminate a city’s food supply.”
Those big city filth will do it to themselves and otherwise be too busy killing each other to range in the country.
The dirt roads in my area are 500x cleaner and less contaminated than any big city streets.
When it rains in places like the LA area, the water runoff alone is so nasty and full of crawling cooties, they have to shut down the beaches.
Blap!