[US EPA. December 22, 2023]. The U.S. Environmental Protection Agency (EPA) has registered biopesticide products containing the new active ingredient Ledprona for three years, a timeframe that is consistent with EPA’s approach to other novel biopesticide products. Ledprona is a new type of pesticide that relies on a natural mechanism–called RNA interference (RNAi)–used by plants and animals to protect against disease. EPA supports advancements in novel pesticide technology because this technology replaces more toxic chemical-based pesticides, provide an additional tool for farmers to address challenges of climate change, and aids in resistance management.
Ledprona is a sprayable double-stranded ribonucleic acid (dsRNA) product that targets the Colorado potato beetle (CPB), a major pest of potato crops grown in the United States, including in the potato-growing states of Colorado, Idaho, Maine, Michigan, Minnesota, North Dakota, Oregon, Washington, and Wisconsin. The CPB feeds heavily on potato plant foliage. If left uncontrolled, CPB will eat and destroy the leaves of the plant. If this occurs around the time of flowering, the plant may not produce potatoes. The CPB is also known to rapidly develop resistance to chemical-based insecticides. This sprayable dsRNA product kills the pest by “silencing” the CPB gene needed to produce the PSMB5 protein, whose role is essential to keeping the CPB alive, without resulting in a genetically modified organism. This RNAi-based pesticide is the first sprayable dsRNA pesticide in the world allowed to be used commercially and sprayed on plants.
Novel pesticide technology can offer alternatives to chemical-based pesticides that may pose higher potential risks to human health or the environment or have reduced effectiveness because of resistance issues. Registered and recommended conventional active ingredients for foliar use against immature and adult CPB currently include the neonicotinoids (e.g., thiamethoxam), the spinosyns, abamectin, novaluron (an insect growth regulator), the diamides (e.g., cyantraniliprole), and some pre-mixes of these (e.g., abamectin and cyantraniliprole).
In May 2023, EPA approved an experimental use permit under the Federal Insecticide, Fungicide, and Rodenticide Act for testing in 10 states (Idaho, Maine, Michigan, Minnesota, New York, North Dakota, Oregon, Virginia, Wisconsin, Washington). In September 2023, EPA opened a public comment period for this proposed registration. EPA considered the comments received and believes it has all the information needed to support its decision to register this novel biopesticide technology. Consistent with its obligation to ensure that the product does not pose unreasonable adverse effects on the environment, including that residues of the product are safe for consumption, EPA has conducted a robust evaluation and determined there is no risk of concern to human health and the environment, including no effects to listed species under the Endangered Species Act. In considering the risk for RNAi technology, such as Ledprona, EPA engaged with international partners and experts in the field via its leadership in the Organisation for Economic Co-operation and Development.