Rapeseed-Mustard is an important Rabi season oilseed and vegetable crop of the Punjab state. The present study was carried out to know the yield gap between recommended practices and farmer’s practices of rapeseed-mustard crop. Therefore, efforts have been made through frontline demonstrations (FLD) on insect-pest management to demonstrate improved plant protection technologies to increase productivity of rapeseed-mustard crop in the district. Fifty frontline demonstrations were conducted on rapeseed-mustard covering an area of 20 hectares and the latest mustard aphid, Lipaphis erysimi management technologies were exhibited. Farmers were randomly selected from adopted villages for conducting frontline demonstration. The average percent increase in yield of rapeseed-mustard under the demonstration fields over farmer’s practices were recorded as 8.11 per cent. Improved insect-pest management practices in rapeseed-mustard Var. GSC-7 gave the highest yield 21.35 q/ha and 21.48 q/ha as compared to the farmers’ practice through the average yield was recorded as 19.29 q/ha and 19.75 q/ha in the year 2017 and 2018, respectively. The mean technology gap, extension gap and technology index were found 0.84 q/ha, 1.89 q/ha and 3.75 percent, respectively. The improved plant protection technologies gave higher mean net return of₹ 67537 per hectare with a benefit cost ratio 5.85 as compared to farmers practice having the mean net return of₹ 60980 per hectare with a benefit cost ratio 5.48. The study on the efficacy of new insecticide Thiamethoxam 25 WG@ 100 gm per hectare against mustard aphid, Lipaphis erysimi revealed that 7 days after spray gave maximum mortality of this pest (88.98% and 90.77%) as compared to Dimethoate 30 EC@ 1.0 ltr gave (78.33% and 77.77%) mortality during the year 2017 and 2018, respectively.