HALT, AMERICAN BEETLE (Anonymous, DDR, 1950s).
The Colorado beetle devastated potato crops across the Warsaw Pact during the Cold War. A Soviet conspiracy was that it had been spread deliberately by the Americans as a method of warfare. Mass pesticide campaigns were initiated, including the mobilisation of school children to kill as many as possible. It even eventually became resistant to DDT.
In reality, the beetle had been present in Europe since the 19th century. It had been eradicated, but was then reintroduced with the arrival of American troops in WWI. Lingering in France, it eventually spread to Germany and by the 1930s was being spread by German expansion. Source
