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Lookup NU author(s): Dr Feras Afifi, Dr Martin EdwardsORCiD, Professor Angharad MR GatehouseORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.BACKGROUND: Cotton bollworm, Helicoverpa armigera, is a major global pest of cotton. Delivery of double-stranded RNA (dsRNA) shows promise as a biopesticide for controlling this insect pest. However, employing RNA interference (RNAi) technology in the field requires enhancing its stability and demonstrating biosafety. RESULTS: Two genes, chitin synthase II and cytochrome p450 protein 6b6, were simultaneously targeted to disrupt the gut physiology of the cotton bollworm. Long dsRNA molecules (≈ 400 bp) encapsulated with a cationic polymer (chitosan) and a cross-linker (tripolyphosphate, TPP) were synthesized to produce nanoparticles ranging from 150 to 300 nm in size, with a positive charge ~40 mV. Encapsulation resulted in a 100% increase in the knockdown effect on larvae that were fed with a diet containing dsRNA–nanoparticle complex compared to those fed with naked dsRNA. Additionally, nanoparticles produced substantially higher mortality than naked dsRNA, even at 100-fold lower concentration. Overall, our findings suggest that chitosan/TPP/dsRNA nanoparticles at low doses (0.1–1 μg g−1) effectively enhance the RNAi effect in H. armigera larvae via oral delivery. In addition, acute oral toxicity tests were conducted on two relevant beneficial bees, Scaptotrigona postica and Bombus terrestris. Consistent with predictions from bioinformatic analyses, no significant lethality or signs of toxicity were observed in these non-target organisms. CONCLUSION: Delivery of dsRNA molecules via nanoparticles was demonstrated to be a promising approach to enhance RNAi activity against H. armigera. Thus, this technology represents an efficient and safe strategy for managing lepidopteran pests. However, further research to optimize these molecules for field application is crucial. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Author(s): Vasquez DDN, Teixeira LA, Alves RF, Cavalcante R, Macedo LLP, Pires CSS, Silva LP, Silva MCM, Afifi FM, Morgante CV, Edwards MG, Gatehouse AMR, Grossi-de-Sa MF
Publication type: Article
Publication status: Published
Journal: Pest Management Science
Year: 2026
Pages: Epub ahead of print
Online publication date: 26/04/2026
Acceptance date: 04/04/2026
Date deposited: 12/05/2026
ISSN (print): 1526-498X
ISSN (electronic): 1526-4998
Publisher: John Wiley and Sons Ltd
URL: https://doi.org/10.1002/ps.70837
DOI: 10.1002/ps.70837
Data Access Statement: The data that supports the findings of this study are available in the supplementary material of this article.
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