Before pesticides go from the laboratory to the farm field, they have to first be vetted by the Environmental Protection Agency. But they’re commonly mixed—sometimes by the pesticide manufacturers, sometimes by the farmers themselves—with substances called adjuvants that boost their effectiveness (to spread more evenly on a plant’s leaf in the case of insecticides, or to penetrate a plant’s outer layer, allowing herbicides to effectively kill weeds). Despite their ubiquity, adjuvants aren’t vetted by the EPA at all; they’re considered “inert” ingredients.
Despite their ubiquity, adjuvants aren’t vetted by the EPA at all; they’re considered “inert” ingredients.
I first wrote about them last year, when adjuvants mixed with fungicides came under suspicion of triggering a large bee die-off during California’s almond bloom. Recently, an eye-popping article by Purdue weed scientists in the trade journal Ag Professional brought them to my attention again. The piece illustrates the unregulated, Wild West nature of these additives.