Spray-Induced Gene Silencing for Postharvest Protection: dsRNA Stability and Insecticidal Efficacy

Sprayable double-stranded RNA (dsRNA) pesticides, based on RNA interference (RNAi), have shown promise in preharvest crop protection, yet their use for postharvest grain storage remains underexplored. In this study, we evaluated the efficacy and stability of sprayable dsRNA in protecting stored rice grains from the lesser grain borer (Rhyzopertha dominica). Results showed significant insecticidal activity, with 72% mortality observed after ingestion of grains stored for 60 days post-treatment, compared to 90% mortality in freshly treated grains. To assess dsRNA persistence, we developed a sensitive detection method for low-input samples. Approximately 73% of the initial dsRNA remained detectable after 60 days of storage, with increased absorption into the rice hull over time. These findings demonstrate the durability and effectiveness of sprayable dsRNA in stored grain protection and underscore its potential as a sustainable alternative to chemical pesticides for postharvest pest management.