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May 13, 2025
By Nate Birt
A new spray-based biopesticide for potatoes could drive future innovation targeting soybean pests while mitigating negative effects for beneficial insects and the environment.
“This really is the dream from a pesticide perspective,” says Dr. Mark Singleton, Chief Commercial Officer & General Manager, Plant Health at GreenLight Biosciences, which developed the product and the bioreactor-based manufacturing technology behind it.
GreenLight Biosciences’ first product, Calantha, a biopesticide, controls Colorado potato beetles like the one pictured here, and could drive future innovation targeting soybean pests while mitigating negative effects for beneficial insects and the environment. Photo Credit: GreenLight Biosciences
The active ingredient, Ledprona, uses a naturally occurring process called RNA interference (RNAi) to silence specific pest genes, ideally when they first emerge as larvae. Ledprona underpins a product from GreenLight Biosciences called Calantha, which became commercially available for potatoes in spring 2024. It’s been studied extensively for the past six years in partnership with the University of Wisconsin Extension.
The product targets a major threat to U.S. potatoes: the Colorado potato beetle. The insect also serves as a proof of concept, paving the way for novel modes of action addressing increasingly challenging pests and groups of pests.
“The new Calantha product is a formulated, double-stranded RNA (dsRNA) that works to reduce the expression of an important gene in the Colorado potato beetle,” explains Dr. Russell Groves, a professor, Extension specialist and chair of the university’s entomology department. “Silencing of this gene results in a cessation of feeding, and this insect dies as a result of starvation or desiccation.”
Singleton acknowledges the term RNA can make people nervous, which is why he describes the technology’s biological basis in relatable terms. Biological creatures including insects and humans are naturally “designed to recycle RNA,” Singleton says.
“Did you have breakfast this morning?” he asks. “If so, you’ve had a dose of RNA.”
The solution offers several advantages compared to other solutions. It only kills a single pest, compared to other pesticides that kill multiple insects, including helpful ones. It disappears from the environment after two to three days compared to pesticides that can linger and filter into soil and water. And it’s safer for human health.
“Stewardship of these technologies will remain critically important, and resistance management of RNAi-based tools will remain a focus of our integrated pest management strategies to conserve these important tools,” Groves says.
Studying the benefits of these technologies could yield new solutions for the soybean production toolbox.
Similar approaches already are in the field and are familiar to many row-crop farmers. SmartStax Pro corn hybrids, which Bayer CropScience introduced for commercial use during the 2021-22 season, similarly silence a key gene in corn rootworm. The pest then dies.
Yet for soybean production, a few technical challenges must be overcome. While Calantha for potatoes is applied to the surface of plant leaves, soybeans struggle to fight against pests such as stinkbugs and Lygus spp., which drill their stylets into the phloem inside leaves, where current products don’t yet reach.
After more than 700 trials of the current technology conducted with farmers, and an extra year of EPA regulatory review prompted because of its lack of nontarget side effects, Singleton sees a bright future. GreenLight’s second product is expected to gain EPA approval soon and will target varroa mites in honeybees. Its third and fourth products will undergo EPA review starting later this year.
Bees and other beneficial insects aren’t harmed by new foliar-applied biopesticides that use formulated, double-stranded RNA (dsRNA) technology found in nature. Photo Credit: Dr. Russ Groves, University of Wisconsin
“If we steward this technology, it’s got a good life ahead of it,” Singleton says. He’s actively exploring opportunities to partner with soy and other farmers to cost-share research and development into new RNA solutions for crop-specific pests.
Agronomists who’ve used the RNAi technology are optimistic that further use and research will illustrate its many benefits.
“If we can improve our beneficial insect population, I think we will be able to reduce insecticide use in the future on other insects such as aphids,” says Wes Meddaugh, senior agronomist at Hancock, Wisconsin-based Heartland Farms. The fifth-generation farm is the largest storage grower in the state and partnered with Groves to study the new technology.
The potential to expand the pest-control toolbox even further also is exciting, adds Dr. Nick David, senior agronomist at RD Offutt Farms. His team also works with Grove and provides agronomic expertise on their potato farms across Minnesota, Nebraska, North Dakota and Wisconsin.
“We hope to see the number of pests controlled through this type of technology increase,” David says.
To better understand RNAi, check out these online resources, says Dr. Russ Groves, a University of Wisconsin entomologist:
