A targeted, gene-silencing approach that could transform pest control and reduce our reliance on chemical pesticides
In the endless battle to protect crops from devastating pests, farmers have long relied on chemical pesticides. These solutions, however, are a double-edged sword—they can harm beneficial insects, pollute the environment, and leave dangerous residues on our food.
What if we could stop pests not with a potent poison, but by turning off a critical gene inside them, with a level of precision that leaves other creatures completely unharmed? This is the promise of RNA interference (RNAi), a revolutionary biotechnology that is set to transform agricultural pest control into a more sustainable and targeted endeavor 1 .
Global RNAi pesticides market value in 2024 4
Year first topical RNAi pesticide was approved by EPA
Higher efficacy of SARNs vs conventional dsRNA
RNA interference (RNAi) is a naturally occurring cellular process, a kind of universal immune system that plants and animals use to defend against viruses and control gene expression. Scientists have learned to harness this mechanism to silence specific genes in pest insects and plant pathogens 5 6 .
Scientists design and introduce a double-stranded RNA (dsRNA) molecule that matches a target gene in the pest.
Inside the pest's cells, an enzyme called Dicer chops the dsRNA into small interfering RNAs (siRNAs).
siRNAs are loaded into RISC, which seeks out and binds to complementary mRNA from the pest's essential gene.
RISC cleaves the target mRNA, preventing production of vital proteins and leading to the pest's death or incapacitation.
By targeting genes unique to specific pests, RNAi can eliminate harmful insects while leaving beneficial ones, humans, and other wildlife completely unaffected.
RNAi breaks down naturally in the environment, unlike persistent chemical pesticides that can accumulate in soil and water systems.
There are two primary strategies for deploying this gene-silencing technology in the field, each with distinct mechanisms and advantages.
This approach involves genetically engineering crop plants to produce the pest-killing dsRNA themselves. When a pest attacks the plant and starts feeding, it ingests the dsRNA, triggering the RNAi process within the pest's body 1 .
Successful examples include transgenic corn targeting the western corn rootworm and virus-resistant papaya and common beans 1 .
This non-transgenic approach is like a spray-on pesticide, but made of RNA. Farmers can spray dsRNA formulations directly onto crops. When pests consume the treated plant surface, they take in the dsRNA, which silences their essential genes 1 .
The first topical RNAi pesticide, 'Calantha' targeting Colorado potato beetle, was approved by the US EPA in 2024 8 .
| Feature | In Planta RNAi (HIGS) | Topical RNAi (SIGS) |
|---|---|---|
| Method | Genetically modified crops produce dsRNA | Direct application of dsRNA sprays |
| Duration | Long-term, built-in protection | Short-term, applied as needed |
| Regulatory Hurdles | Higher (involves GMOs) | Lower (non-transgenic) |
| Flexibility | Low (fixed after planting) | High (can be used flexibly) |
| Key Challenge | Ensuring stable gene expression and public acceptance of GMOs | Improving environmental stability and delivery efficiency |
A key challenge with topical RNAi, especially against sucking insects, is that dsRNA is a large, fragile molecule. A 2025 study introduced a groundbreaking solution: Self-Assembled RNA Nanostructures (SARNs) 8 .
The research team set out to create a more stable and efficient form of dsRNA for delivery:
Instead of using long, straight dsRNA, they designed single-stranded RNA sequences that could self-fold into compact, 3D nanostructures inspired by naturally stable RNA motifs.
SARNs were programmed to contain pools of multiple siRNAs targeting essential pest genes like the ecdysone receptor (EcR) and chitinase 10 (Cht10).
SARNs were produced cost-effectively using an E. coli system and tested against red flour beetle and brown planthopper pests.
The SARN platform demonstrated significant advantages over conventional dsRNA:
This experiment underscores that the future of topical RNAi lies not just in the RNA sequence, but in its physical formulation and delivery, with nano-engineering offering a path to overcome major biological barriers.
| Pest Species | Target Gene | Treatment | Mortality/Deformity Rate | Key Finding |
|---|---|---|---|---|
| Red Flour Beetle | TcEcR | Conventional dsRNA | ~40% | SARNs showed significantly higher efficacy and stability |
| Red Flour Beetle | TcEcR | SARN | ~80% | |
| Brown Planthopper | NlEcR | Conventional dsRNA | Low (Highly degraded) | SARNs successfully overcome the degradation barrier in sucking insects |
| Brown Planthopper | NlEcR | SARN | ~65% |
The SARN experiment demonstrates that nano-engineering of RNA structures can dramatically improve the stability and efficacy of RNAi pesticides, particularly against challenging pests like sucking insects that are traditionally difficult to control with conventional dsRNA.
Bringing an RNAi-based pesticide from concept to field trial requires a sophisticated set of tools and reagents.
| Research Reagent | Function in RNAi R&D |
|---|---|
| dsRNA/siRNA Synthesis Kits | For producing the initial RNA triggers; used for small-scale testing and proof-of-concept studies. |
| In Vivo siRNA | Specially designed siRNAs with chemical modifications to resist degradation in living organisms, crucial for testing in live insects. |
| Nanoparticle Materials (e.g., Chitosan, Lipids) | Used to create protective capsules that shield dsRNA from environmental degradation and enhance its uptake by pest insects. |
| E. coli HT115 (DE3) Strain | A workhorse for large-scale, cost-effective production of dsRNA through microbial fermentation. |
| T7 RiboMAX Express System | A cell-free transcription system for rapid production of large amounts of RNA in a test tube. |
| RNA Ligases and Gel Extraction Kits | Essential for molecular biology workflows, such as constructing and purifying complex RNA nanostructures (e.g., SARNs). |
| Nuclease Assay Kits | Used to measure the degradation of dsRNA in insect guts or the environment, helping researchers screen for more stable formulations. |
Large-scale production of dsRNA is becoming more feasible through:
These approaches are driving down costs and making sprayable RNA pesticides a practical reality 8 .
Key advancements in delivery systems include:
These innovations are critical for overcoming biological barriers to RNAi efficacy .
The global RNAi pesticides market, valued at USD 1.2 billion in 2024, is predicted to grow rapidly, reflecting the immense confidence in this technology 4 . This growth is fueled by the pressing need for sustainable agriculture solutions.
Research will continue to focus on smarter nanoparticles and formulations that improve the protection, uptake, and movement of RNA within both the plant and the pest .
Using genomics and bioinformatics to identify unique, essential genes in pests that, when silenced, yield the most effective control with zero off-target effects.
RNAi technology represents a paradigm shift in pest control. By moving away from broad-spectrum chemicals to a targeted, gene-silencing approach, it offers a path to productive agriculture that exists in harmony with the environment. Whether engineered into the plant itself or applied as a spray, RNAi is a powerful tool born from understanding nature's own language. As research overcomes the final hurdles of delivery and stability, the quiet revolution of RNAi is poised to speak loudly in the fields of the future.
References will be listed here in the final publication.