Elevated Soil Silicon Supplementation Enhances Silicon Accumulation in Rice Plants and Suppresses Brown Planthopper Population by Altering Physiological Fitness

Background and aims Silicon (Si) application is increasingly recognized as an important component of integrated pest management, as it enhances plant resistance against herbivorous insects. This study aimed to evaluate the effects of different soil silicon levels on Si accumulation in rice plants and to determine the subsequent impacts on the performance of the brown planthopper (BPH), Nilaparvata lugens Stål. Methods Rice plants were grown in soil amended with four silicon levels: 0, 100, 200, and 300 kg SiO₂ ha⁻¹. Silicon uptake and accumulation in rice plants were measured, along with total soluble protein content. The performance of BPH on Si treated rice plants, including phloem feeding, nymphal growth, survival, and population establishment, was evaluated. Correlation analyses were conducted to assess relationships between soil Si levels, plant Si content, and BPH population size. Results Increased silicon application significantly enhanced Si uptake and accumulation in rice plants, while reducing total soluble protein content. Silicon-treated rice plants negatively affected BPH feeding, reduced nymphal growth and survival, and suppressed population establishment. Soil Si amendment was strongly and positively correlated with plant Si content and strongly and negatively correlated with BPH population size at significant levels. Conclusions Silicon application enhanced rice resistance to BPH by altering plant chemical composition and impairing insect performance and population growth. These findings highlight the potential of silicon fertilization as a sustainable strategy within integrated pest management programs.