 Volatiles into their air once the beetle chews on the plant, a scent meant to attract enemies. The problem? Minnesota has none. So even though the plants are releasing these green volatiles and pleading that some predator of Japanese beetle come kill it, nobody gets the message because they're an invasive exotic. Gristick says the pests munch on the leaves of over 300 plants as adults, and the babies chew up the roots of those plants.