Graphene oxide as a pesticide carrier for enhancing fungicide activity against Magnaporthe oryzae

Abstract

The fungus Magnaporthe oryzae causes disastrous consequences for rice growth. Carbendazim (CBZ) has been extensively used for disease management. However, because of the heavy use of traditional CBZ, a majority of CBZ is wasted, resulting in an extremely low utilization rate and severe pollution problems. In this work, carbendazim–graphene oxide (CBZ–GO) and carbendazim–ultrasonic graphene oxide (CBZ–UGO) were synthesized for use against rice blast. The EC₅₀ of CBZ–GO and CBZ–UGO on the mycelium of Magnaporthe oryzae was 0.28 and 0.41 μg mL⁻¹, which showed 2.29- and 1.56-fold higher antifungal activity than the EC₅₀ (0.64 μg mL⁻¹) of CBZ, respectively. GO can destroy mycelia and compromise cell integrity as confirmed from the SEM images of mycelia. Nanocomposites can damage glutathione on the cell membrane through an electron transfer to weaken the fungus cell activity. Moreover, the application of nanocomposites on rice seedlings significantly reduced the severity of rice blast compared to other processing groups in a greenhouse experiment. Therefore, GO as a high-efficiency carrier would offer an important opportunity for managing fungal diseases.