Development of silicon-augmented resistance in rice against brown planthopper (Nilaparvata lugens (Stål))

The brown planthopper (Nilaparvata lugens (Stål)) is a major pest of rice, causing severe yield losses and overcoming many conventional resistance sources. Silicon has emerged as a promising supplementary defense factor that strengthens plant tissues and activates biochemical defense mechanisms. Exploring silicon-augmented resistance offers an eco-friendly strategy to enhance rice resilience and reduce reliance on chemical pesticides. A replicated field trial was conducted at the Research Farm, College of Agriculture, Bhawanipatna, Odisha University of Agriculture and Technology (OUAT), Odisha, to study the impact of varietal resistance and the foliar application of silicon (Si), as well as their interaction effects on brown planthopper (BPH) during the kharif crop season of 2023. Ten treatment combinations were used during the trial, including 2 rice cultivars (Lalat and TN1) and 4 Si doses: sodium silicate (2 g mL-1), calcium silicate (2 g mL-1), nano sodium silicate (200 m gL-1) and an untreated check. When compared to the susceptible check, TN1, the resistant rice cultivar Lalat consistently showed a lower number of BPH and nano-Si formulations outperformed non-nano Si compounds in reducing the BPH population. Si-treated Lalat cultivars consistently showed lower BPH population, regardless of the Si formulations used. This suggests that Si application and host plant resistance are compatible. The additive effect of Si further increases resistance in tested rice cultivars and the 2 can be successfully combined for long-term pest management in the rice ecosystem. Plots treated with Si and the Lalat cultivar showed a favorable prey-predator ratio, indicating that the Lalat variety is less detrimental to predators and supports their abundance. Grain yields were higher in the Lalat rice cultivars treated with nano-sodium silicate (4883 kg ha-1) and nano-calcium silicate (4617 kg ha-1).