Seed dressing with triflumezopyrim controls brown planthopper populations by inhibiting feeding behavior, fecundity and enhancing rice plant resistance

Background Triflumezopyrim (TFM) is a novel mesoionic insecticide that has the characteristics of high efficiency with a low dosage, which is mainly controlled hopper species. A previous study demonstrated that seed dressing with TFM effectively controlled rice planthoppers population in mechanically-transplanted rice fields; however, the mechanistic basis for control was unclear. Results The study shows that seed dressing with TFM resulted in elevated levels of oxalic acid, flavonoids, phenolic substances, callose, and other compounds associated with Nilaparvata lugens resistance in rice plant; and low TFM residue content of rice plants stem and gain. Host choice behavioral experiments showed that N. lugens females prefer feeding on untreated rice plants. Electrical penetration graph (EPG) data showed that seed dressing with TFM at medium and high doses significantly prolonged the non-probing period and inhibited phloem ingestion in N. lugens females. These changes caused a significant decrease in the female secretion of honeydew, expression of genes encoding vitellogenin and juvenile hormone acid methyltransferase, body weight and longevity, and significantly influenced several physiological parameters and resulted in impaired oocyte growth, fecundity, and population. Field survey data showed that seed dressing with TFM was efficacious and relatively durable in protecting rice plants from planthoppers' infestation. Conclusion In summary, the study revealed seed dressing with TFM enhances rice plant resistance to N. lugens by limiting phloem ingestion and increasing the N. lugens non-probing period; this leads to reduced fecundity of females and lowers N. lugens numbers in the field. This article is protected by copyright. All rights reserved.