Evaluating Oryza sativa (Poales: Poaceae) as a host for Diuraphis noxia (Hemiptera: Aphididae): implications for pest management.

Russian wheat aphid (Diuraphis noxia, Mordvilko ex Kurdjumov) (RWA) is a major pest of wheat and barley. Although rice (Oryza sativa L.) is not considered a primary host, RWA has been found on drill-sown rice in Australia prior to the application of permanent water. This study investigates the persistence of RWA on rice and evaluates plant responses to infestation, with the aim of determining whether pest management interventions are justified in Australian rice-growing systems. A series of replicated glasshouse trials was conducted using single and repeated aphid infestation pressures. Results demonstrate that rice is an unsuitable host for RWA, with aphid populations declining over time in all treatments, suggesting that rice does not support self-sustaining populations. A single infestation caused no measurable injury to rice, while repeated infestations led to only minor physiological effects, with plants recovering rapidly after aphid removal. These findings indicate that RWA does not pose a direct threat to rice production in Australia under current farming practices and that the routine application of insecticides for its control in rice is not justified.