A University of Maryland study shows predators are unlikely to be affected by eating pests treated with RNA-based genetic technologies.
Milkweed bugs like this one are very susceptible to RNA interference, making them good model insects for testing its effects.
Image Credit: Rhododendrites - Wikicommons
Researchers at the University of Maryland showed that RNA interference (RNAi), a relatively new alternative to chemical pest control in agriculture, can be transmitted from target insects to predators, but the effect is small even under extremely limited “ideal” lab conditions. Their results suggest that RNAi-based pest control could safely help farmers manage pests while reducing some of the environmental concerns associated with traditional insecticides, but caution must be taken to monitor risks. The study was published in June, 2026, in Scientific Reports.
“Very unexpectedly, we found that if RNA interference is used to target a particular insect, other insects that feed on it can also be impacted by the treatment,” said Leslie Pick, a professor of entomology and co-lead author of the study along with Associate Professor Kelly Hamby. “Our quantitative analysis showed it is very unlikely to be an issue in the field, and that this approach is still more species-specific than many chemical pesticides. Nevertheless, since it can occur, it is something people using this method should be aware of and consider for risk assessment.”
RNAi-based pest control works by silencing or turning down important genes in a target insect that are necessary for survival. The technology is currently being used against the Colorado potato beetle and corn rootworm, and it is being developed against certain termites, ticks and other pests. Because it is designed based on a gene or genome sequence, RNAi can be made to target genes that are specific to an individual species.
But some genes are similar among different species, and it is important to ensure that genetic silencing in pests doesn’t find its way into other non-target organisms. To better understand the risks of non-target transfer through the food chain, Pick, Hamby and their team set up a “worst case scenario” that made it as easy as possible for genetic silencing made through RNAi technology to transfer from one insect to another.
They used the large milkweed bug, Oncopeltus fasciatus, a non-pest species that was known to be highly susceptible to RNAi. They injected female milkweed bugs with the gene-silencing agent (dsRNA) and then fed their eggs to other milkweed bugs that had never been exposed to dsRNA. The results showed that RNAi effects were passed on through the food chain in this lab model. The researchers say that to their knowledge, this “trophic effect” (as food chain transfer is known) has never been demonstrated before now.
Because large milkweed bugs are very susceptible to RNAi, the results demonstrate that RNAi transfer through the food chain is low, even within the same species under ideal laboratory conditions. Transfer to a different species would be even less likely, according to Pick and her colleagues.
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This study resulted from a collaboration between the applied research lab of Associate Professor Kelly Hamby and the basic research lab of Professor Leslie Pick in the Entomology Department at the University of Maryland.
Additional authors from the Pick lab include: previous MS student Ebony Michelle Argaez (now a PhD student at UCSD), previous lab technician James B. Digel, previous PhD student Katie Reding (now a Postdoc at GW), and previous postdoctoral student Muhammad Salim Hakeemi.
