The effect of different amounts of nitrogen applied on rapeseed cultivars on nutrient reaction and protein metabolism of Helicoverpa armigera

The physiological feeding reactions of cotton bollworm were investigated by evaluation of nutritional indices and enzyme activity of larvae reared on different rapeseed cultivars including, Sarigol, Rgs003 and Slm046. The experimental plants were treated by amounts of urea fertilizer equivalent to 120, 240 and 360 kg per hectare, in three development stages of plants. The nutritional indices of Helicoverpa armigera on different rapeseed cultivars were calculated by Waldbauer's formula. The total leaf protein in three rapeseed cultivars were significantly increased with increase of nitrogen level. The lowest and highest values of measured nutritional indices were observed in larvae reared on control and treated plants with 360 kg/hec of nitrogen, respectively. Also results indicated that there was not significant difference between larval nutritional indices which reared on plants treated with 120 and 240 (kg/hec). Similar results were obtained for larval digestive enzyme activity.