The discovery of this process—called RNA interference (RNAi)—earned two scientists the 2006 Nobel Prize in Physiology or Medicine. It also sparked a race to develop new tools based on it. Scientists soon realized that if you could introduce dsRNA into a pesky pathogen—a particularly irritating fungus, for example—you could instruct that pathogen’s cells to destroy its own mRNA and stop it from making crucial proteins. In essence, they could switch off genes within pathogens at will. “We’re just going in there and looking at the orchestra of genes and proteins out there and we’re silencing the violins. That’s all we’re doing,” says Michael Helmstetter, chair of RNAissance Ag, another startup vying to bring RNA crop sprays to the market.

A handful of RNA sprays are already in the works. RNAissance Ag is working on a spray that targets the diamondback moth, which has an insatiable appetite for cabbages and has already evolved some resistance to common pesticides. GreenLight Biosciences has an RNA spray targeting the Colorado potato beetle that’s currently being evaluated by the Environmental Protection Agency. The company is expecting a decision on that spray by the middle of 2022. It’s also working on a spray for Botrytis, as well as one that combats the Varroa mite, a widespread pest that infects honey bees. After initial laboratory trials, GreenLight is now field testing its Botrytis spray on grapes in California and strawberries in Italy. Singleton says they’re looking to find out how long the spray sticks to plants and how it compares to chemical fungicides.