A native of the Rocky Mountains, the beetle now occurs across the Northern Hemisphere, causing more than half a billion dollars of crop losses each year. It’s a master of resistance, making it hard to control. The pest was an early driver of research into chemical pesticides starting in the 1930s. Ever since, it has evolved immunity to one compound after another—now more than 50 pesticides, representing all major types of active ingredients.

“They were chewing through treated plants like it was nothing,” Andrei Alyokhin, an entomologist at the University of Maine, says of the moment, in 2001, when farmers in Maine noticed that a still-new class of pesticides, neonicotinoids, were no longer controlling the beetle. Finding additional tools has been “increasingly difficult,” he adds.

This year, however, U.S. farmers will have a new weapon against the pest, one that works in an entirely different way from traditional pesticides and that proponents say should be safer for people and the environment. Based on a mechanism called RNA interference (RNAi), the spray targets a vital gene in the Colorado potato beetle. The gene target is unique to the pest and its close relatives, which should prevent damage to pollinators and other species. “You can … hit the insect you want to kill with precision,” says Subba Reddy Palli, an entomologist at the University of Kentucky who published a review last year in Frontiers in Insect Science describing the development of RNA-based pesticides. “You cannot get anything better than this.”