Mao Zedong controlled China with an iron fist for more than three decades, and is widely believed to have caused the death of roughly 50 million people during his reign. His two main political campaigns — the Great Leap Forward and the Cultural Revolution — are considered terrible failures in large part because of the death toll and suppression of human rights. One of the reasons for the massive death toll? A fickle, half-baked idea of Mao’s called the Four Pests Campaign.

The Four Pests Campaign began in 1958. It was one of Mao’s first acts as part of the Great Leap Forward, aimed at eliminating four creatures which Mao believed put the health and hygiene of the average Chinese citizen at risk. Three of them — mosquitoes, flies, and rats — may make some sense, but rendering them extinct, even locally, is a fool’s errand. The fourth pest, the sparrow, does not seem to belong on this list. But Mao observed that sparrows would eat the grains planted by Chinese workers and, therefore, reduce the value of the people’s labor. So they made the list, too, and were more effectively targeted than the other three “pests.” Mao’s government began a large-scale propaganda campaign to get peasants to shoo or kill sparrows on sight. The poster above is one example: it shows a child armed with a slingshot and the text below, translated, means “Everyone come and fight sparrows.”

The campaign was successful on its face, as the sparrow was nearly rendered extinct in China. But it turns out that sparrows did not just eat grains. They also ate insects — specifically, locusts. The locust population, left unchecked, ate a lot more grain than the sparrows ever could.

By the time Mao’s government noticed and could react, two years had passed, and the damage was already done. The ecological imbalance caused by the Four Pests Campaign helped spur on massive food shortages and, in turn, the death of hundreds of thousands if not millions of people.

Bonus fact : In Uganda, fried grasshoppers are a delicacy, served with onions (and with their wings removed). Grasshopper collectors use bright lights to attract large amounts of the insects to gather in a small area, and then quickly gas and capture them. Unfortunately for the grasshopper sellers, though, Uganda had power outages in December, as reported by the AFP — meaning no lights, and therefore, a grasshopper shortage.

From the Archives: Flies Fear Ugly Bags of Mostly Water: More about pest control.

Related: “The Private Life of Chairman Mao” by Li Zhi-Sui. 98 reviews averaging 4.5 stars. Available on Kindle.