Mao's Four Pests Campaign was particularly disastrous and ended killing millions in famine. He decided that sparrows, which ate some fruits and seeds, should b

Mao's Four Pests Campaign was particularly disastrous and ended killing millions in famine. He decided that sparrows, which ate some fruits and seeds, should be destroyed. He didn't realize that they also eat locust larva and other pests, which exploded in population without sparrows. Those pests ended up killing massive amounts of crops after the people were ordered to eliminate all sparrows and their eggs -- it ended in widespread starvation.