Field experiments were conducted at Sakha, Kafr El-Sheikh, Egypt; to investigate the effect silica combined with mineral nitrogen on rice yield, and stem borer Chilo agamemnon Bles. Applying potassium ore combined with 92 kg N/fed. Produced the highest panicles/m² (814.31) compared to other silica applications or lower nitrogen levels. The same trend was observed with panicle weight. One-thousand grain weight was higher in Egyptian hybrid 1 than in Giza 178. The grain yields were also highest with potassium ore for both cultivars at the rate of 92 kg N/fed. Rice stem borer infestation was higher in hybrid than in inbred cultivar. Both dead hearts and white heads gradually increased by the increase of nitrogenous applications; from 2.65 to 4.14 % dead hearts, and from 3.77 to 5.59 % white heads due to nitrogenous increase from 23 to 92 kg/fed., respectively. The highest dead hearts (4.92 & 5.28) and white heads (9.42 & 7.06 %) were detected in plots without silica. From the data of this experiment, it could be concluded that Egyptian hybrid 1 yielded more than Giza 178, particularly with using 92 kg N/fed., combined with potassium ore at 500 kg/fed.. It was found that silica applications reduced the stem borer infestation, regardless of the cultivar and nitrogen rates.