Gene-specific double-stranded RNAs induce mortality in the South African mealybug Delottococcus aberiae

The South African mealybug Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is an invasive pest in Mediterranean citrus orchards, leading to fruit deformation and economic losses. Following the withdrawal of key insecticides, novel and species-specific control strategies are urgently needed. RNA interference (RNAi) is a promising biotechnological tool for targeted pest management, offering minimal impact on non-target organisms.

In this study, we developed and validated an RNAi-based approach to silence essential genes in D. aberiae using both microinjection and oral delivery of double-stranded RNA (dsRNA). Six conserved genes, Actin-α, ATP synthase-β, V-ATPase subunit A, Ribosomal protein like S13, Krüppel homologue-1, and ADP/ATP translocase, were selected for silencing. Real-time quantitative polymerase chain reaction (RT-qPCR) assays confirmed effective downregulation of five of them, particularly V-ATPase subunit A and ATPsynthase-β. Both delivery methods significantly reduced survival in insects targeted with most dsRNAs. Feeding assays demonstrated that ingestion of recombinant dsRNA produced in Escherichia coli also triggers gene silencing and lethal effects.

This study demonstrates effective RNAi-mediated gene silencing in D. aberiae, highlighting its potential as a species-specific and sustainable control strategy. These findings pave the way for the development of RNAi-based biopesticides for the integrated management of invasive citrus mealybugs. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.