Seed Coating with Triflumezopyrim Induces the Rice Plant’s Defense and Inhibits the Brown Planthopper’s Feeding Behavior

Abstract

Triflumezopyrim (TFM), a novel mesoionic insecticide, has been effective in controlling sucking insect pests such as the brown planthopper (BPH). However, the mechanism of TFM as a seed coating agent in paddy fields remains unclear. Here, we investigate the seed germination rates (>80%) and seedling emergence rates (>85%) of rice treated with TFM at 0, 22.5, 45.0, 67.5, and 90.0 g a.i. ha−1 with no significant effect on germination rates. In addition, the low TFM residue concentration (0.04 mg. kg−1) is maintained in the rice stem. Meanwhile, the TFM seeds’ treatments lead to increased oxalic acid, flavonoids, total phenol, callose contents, and elevated C/N ratio in rice plants at 60 and 90 days after sowing (DAS). The electrical penetration graph (EPG) results indicate that TFM as a seed coating treatment prolongs the non-probing period and inhibits phloem sap ingestion at 90 DAS. Furthermore, the mechanically transplanted rice treated with TFM provides long-term prevention against the BPH infestation. This study demonstrates that seeds treated with TFM play a vital role in controlling the BPH population up to >90%. These results provide a novel valuable control strategy for BPH in the rice fields.