Silicon fertilization reduced rice yellow stem borer scirpophaga incertulas (walker) and brown planthopper nilaparvata lugens (Stål) infestations but limited effects on plant traits

Rice yellow stem borer-RYSB (Scirpophaga incertulas Walker, Lepidoptera: Pyralidae) and brown planthopper-BPH (Nilaparvata lugens Stål, Hemiptera: Delphacidae) are two major insect pests in rice. However, to control these insects, silicon (Si) supplementation could be an alternative and sustainable methods than chemical intervention. We aim to investigate the role of silicon on the reduction of BPH abundance and % white ear head (WEH) by RYSB infestation in semi-field pot experiment with two rice varieties (BRRI dhan74 and BRRI dhan92) and three foliar silicon levels (0, 120 and 240 mg SiO₂ L⁻¹). We estimated BPH number and % WEH with key plant physical traits, chlorophyll contents and yield parameters. The number of BPH and % WEH was significantly reduced with high foliar silicon dose than control. The number of panicles per plant increased with high silicon dose but no effects in other plant traits. The total chlorophyll (mg/L) and carotenoids (mg/L) content was increased significantly with high silicon treatment than control. Yield parameters such as 1000 dry grain weight (g) and root biomass (g) were increased in high silicon dose. The foliar silicon content (ppm) was found higher in leaf when treated with higher dose. The % leaf silicon content showed significant negative correlation with BPH number and % WEH, respectively suggested that silicon was negatively associated with RYSB and BPH infestation. Our study suggested alternative management of RYSB and BPH through silicon additionally improving plant traits, chlorophyll content and yield parameters.