GMOs have a bad reputation , but 20 years after they were first planted in farm fields, they are having an unintended side effect: helping non-GMO crops.

Many genetically modified organisms were engineered with insect-killing proteins to eliminate or reduce the use of pesticides. The most widely used insect-killing protein comes from a microbe called Bacillus thuringiensis (often abbreviated “Bt”), and the hazards associated with seem largely limited to insects . Since the first Bt crop was planted in 1996, GMOs have been immune to the corn borer and earworm pests-nicknamed the “scourges of corn.”

To prevent Bt-resistance in these pests and to confine GMO genes to their intended crops, the EPA mandates farmers plant non-GMO plants around the periphery of GMO fields- a moat of sorts.