EPA Fast-Tracking of Gene-Altering Pesticide Sparks Concerns

By reporter Shannon Kelleher. Originally published at The New Lede. 

US regulators are fast-tracking a novel, gene-altering insecticide in an unusual move that would greenlight the product for three years of commercial use before a standard testing period is completed.

Calantha, a product of the company GreenLight Biosciences, contains the active ingredient ledprona, which uses a mechanism called RNA interference (RNAi) to kill the Colorado potato beetle, a notorious pest, by turning off genes it needs to survive. Calantha would be the first pesticide spray using RNAi, though the technology has been genetically engineered into some corn plants to protect them from the corn rootworms, and RNAi has a history of use in medical therapeutics and vaccines.

The EPA just granted GreenLight Biosciences an Experimental Use Permit (EUP) in May, giving the company two years to gather and assess data from use of the new product in limited test plots. But now the new pesticide could be widely sprayed on potato crops around the country as early as this spring.

Critics fear that the new pesticide is being rushed to market without sufficient data to demonstrate that it is safe for human health and the environment. They also question whether it will be effective.

“It’s a huge precedent-setter,” said Michael Hansen, a senior scientist at Consumer Reports. “This is a new form of pesticide which has never been on the market before. When this is a new class [of pesticide], you shouldn’t be cutting corners.”

The Environmental Protection Agency (EPA) said Friday that it is extending the public comment period for ledprona following a request from the environmental group Friends of the Earth. The deadline for the comment period, which was scheduled to end October 13, has been moved to October 30.

Unintended Consequences

Agrichemical companies applaud gene-silencing pesticides as a promising solution to the problem of pest resistance and an answer to consumers’ call for pesticide residue-free products.

In 2021, the US Department of Agriculture wrote a letter to the EPA strongly encouraging the agency to authorize ledprona for experimental use, writing that it “could displace some broad-spectrum insecticide usage” and could help potato growers manage the invasive insect.

Multiple studies have “confirmed” that the product has no harmful effect on “people, pollinators, birds, fish or other non-target organisms,” said a spokesperson for GreenLight Biosciences. “Additionally, unlike the commercial chemical pesticides commonly used to control Colorado Potato Beetle, Calantha leaves no detectable residues on food, soil, water or in the atmosphere,” the spokesperson said.

Still, opponents fear embracing this biotech alternative to chemical pesticides without carefully assessing risks could simply create new problems. Gene-silencing pesticides, which large companies including Bayer, BASF, and Syngenta are also developing, could potentially harm off-target species and jeopardize farmers’ health, critics argue.

“We can’t assume that because a technology is biological and not chemical that it is necessarily going to be safe,” said Kendra Klein, deputy director for science at Friends of the Earth and an author of a 2020 report that calls gene-silencing pesticides “a vast, open-air genetic experiment”. “We are considering releasing a material into the environment that will genetically engineer organisms in real time. We have such a long history of unintended consequences of technologies in agriculture – it would be foolish to not assume that there will be unintended consequences to this technology.”

The gene-silencing mechanism used by such pesticides can be triggered whenever they encounter a matching or similar genetic sequence, noted Klein.

“We’re talking about potentially thousands of other species that would have related genetic sequences,” she said.

The EPA said in a press release that EUP experimental testing will continue during the initial commercial registration period and data from it “may be used in a future application for this product to amend its directions for use.”

But critics said that is not sufficient. The EPA should know, for instance, how spraying the pesticide might affect species other than the intended target, including endangered beetles and the birds and amphibians that prey on the potato pest, said Jaydee Hanson, the policy director at the Center for Food Safety.

“The EPA had done a pretty good job leading up to their abrupt notice that they wanted to approve this as a pesticide,” said Hanson. “It’s not a bad job for the start of a field trial. But it’s a grossly incomplete job for turning this into an approval of the pesticide.”

Immune Response and Efficacy Concerns

Consumer Reports’ Hansen said he commends the EPA for having the company consider effects on endangered species and for looking at both the active ingredient and the formulated product when conducting tests. “Those are big steps forward,” he said.

However, Hansen remains concerned about the possibility that the new pesticide could trigger an immune system response in humans. An analysis by GreenLight Biosciences previously identified two human transcripts that could potentially be affected by ledprona, although the final EPA human health risk assessment states that “there is a reasonable expectation that ledprona is unlikely to affect these genes in vivo.”

“But they don’t present enough data for us to see whether that’s true,” said Hansen.

The EPA notes in the assessment that double-stranded RNA molecules that are on the longer side, such as ledprona, “are generally considered candidates to induce innate immune responses.” As a result, the agency concludes that farmers and others working with the pesticide should wear respirators to avoid any risks from inhaling the pesticide.

However, the agency is not requiring “any kind of verification that everyone’s going to be wearing [personal protective equipment] or even monitoring any of those folks to see if anything is happening,” Hansen said. “It seems to me almost like a ‘don’t look, don’t find’ strategy.”

Hansen also wonders about the pesticide’s efficacy – and the efficacy of RNAi pesticides more generally. A 2021 Scientific Reports study assessed a similar double-stranded RNA, which was being developed for a spray to combat the same potato pest. It found that within nine generations, 11,100 times the original quantity of pesticide was needed to get the same effect – an “extremely high” level of resistance, according to the study itself.

“I would want to see the same thing on this product [ledprona] before it was ever approved, because if it does select for resistance very rapidly, that’s not useful,” said Hansen. “With most chemical pesticides you don’t see something like that,” he added. “That caused me to wonder if this whole field will just collapse.”

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  1. tegnost

    What is wrong with these people?
    As for not studying the impacts, everyone must have a smartphone so google/apple data mine everyones phone (the mrna eua led me to this conspiritorial conclusion, for better or worse) and the side effects will show up in the data models (private data models, you know, trade secrets…) and “partner” with big ag/big pharm, they find the negative impacts but are not liable for them. Liability being the only impact they give two f’s about…

  2. Kurtismayfield

    Although I agree with the sentiment that the EPA is rushing this into the wild without proper testing, I have to quibble with the title. RNA silencing is not “gene altering”, it is making sure the protein is not translated and hence kills the pest, but the DNA is never changed.

    I would also like the company to test this like you would a drug; go though the four stages of clinical trials to make sure it will not have adverse effects on humans. Although the odds of the RNA being stable by the time a human eats the crop is slim, I would rather have anything being used on our food to be tested.

    1. JBird4049

      This does not strictly have to do with this latest bug killer, but I under that this might not actively change the DNA, but it will monkey around with the expression of the RNA. It is another way of killing out in the wild without being sure of the parameters. Remember DDT and neonicotinoids?

      Honestly, I am worried fricking terrified about Big Ag, like Big Oil, Big Pharma, FIRE sector, the railroads, and the Military-Industrial-Congressional Complex keeps looking for new ways to make money while actively avoiding even the appearance of being responsible. It is just one thing after another with Congress and the various agencies being the Three Monkeys.

  3. Mikel

    Consumer Reports’ Hansen said he “commends the EPA for having the company consider effects on endangered species…”

    With these fools in the world, all species are endangered (yes, including humans).

  4. playon

    I assume that as with the FDA, our EPA also allows the testing of these things to be carried out by the companies themselves, without government oversight. This allows companies to rig the trials (as has been done by the pharmaceutical industry). What could go wrong, indeed…

      1. ambrit

        Back in the ’60s, the mantra was “Plastics!” By Timbuk3s time in the ’80s it was “Nuclear!” By the Zeros it was “Finance!” Today, it’s “Bio!”
        Better ad a full body isolation suit to those shades!
        I knew there was a reason that Saint Elon and the Musketeers want to move off planet.

        1. divadab

          “Saint Elon and the Musketeers” are delusional – this is our planet, there is no Planet “B”.

          It seems to me that this focus on living on Mars or whatever is avoidance behavior.

          Evolution just keeps on rocking…..whatever rich hubristic fools believe. The same iron laws apply to this RNA pesticide – once it’s loose, it’s part of the living web.

    1. ambrit

      Does the “seriousness” of the comment matter?
      I would imagine that histrionic comments would be dismissed out of hand. The eternal search for “Symbolic Capital” must influence the weighting of comments.
      Short form; are we to tailor comments to appeal to PMCs? [Not an insignificant concern.]
      Or, will sheer number of comments have a “quality all it’s own?”

  5. Piotr Berman

    I do not see how RNAi molecule could be more dangerous than a chemical poison, and perhaps it is more efficiently eliminated from environment. Triggering innate immune system means that the molecule has general properties of a virus — in the opinion of innate immune system, and kudos to that system if it destroys copies of that RNAi as a result.

    That said, I can imagine why resistance may develop faster than for a chemical poison. A selective poison typically binds selectively to proteins, selectivity varies. Gene for that protein may mutate, or dependency on that protein may mutate (e.g. protein perform the necessary task etc..) But RNAi can be disabled with an additional way, somewhat perversely, RNAi themselves can be silenced by decoys. Gene for the target protein can have a part of it copied, creating a pseudogene, and trancripts of that pseudogene does not do much except binding to RNAi’s (that is one of many types of regulation of “gene expression”, making gene transcripts. For each major type of regulatory mechanisms there is a mechanism, perhaps rare, that disables it) And this is a type of mutation that can form a dose dependent resistance. If our beetle is lucky, the copy conferring resistance is repeated many times, thus increasing the new necessary dose.

    But if pesticide is harmless, than it would solve the problem for potato growers for few years, potato prices would go up again and we will have to eat more of something else, e.g. buckwheat (cheap these days because Russian buckwheat is still not under sanctions, and rubble went down).

    1. divadab

      Yes! The same iron laws of evolution apply to these created RNA viruses as to all living entities. Mother nature bats last, she’s been around for a lot longer than we supposed brains of the outfit.

  6. GC54

    This should ultimately increase the yield of French Fry precursors. Celebrate! I wonder what the epigenetic effect of a deep fryer will have.

  7. steppenwolf fetchit

    I gather there have been Organic and then Certified Organic potato growers growing potatoes for years in the teeth of Colorado potato beetles. How have they done it all these years without this new RNAi technology?

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