 The relationships between JH level and imidacloprid concentrations showed a significant negative correlation . In contrast , molting hormone ( MH ) level in larvae fed on control plants was significantly higher than that on treated plants . JH : MH values in fourth instars developed from larvae feeding on rice plants treated with 00 , 00 , 00 , 00 , and 000 ppm imidacloprid increased by 00 . 00 , 00 . 00 , 00 . 00 , 00 . 00 , and 0 . 0 times , respectively , compared with control . JH and JH : MH ratio in larvae fed on Wujing 00 plants treated with imidacloprid were significantly lower than those fed on Fengyouxiangzhan under the same treatments . JH level in adult females that developed from larvae feeding on rice plants sprayed with imidacloprid significantly decreased with increase in imidacloprid concentration , but it increased compared with control . JH level in adult females was associated with times of imidacloprid application . JH level in adult females developed from larvae feeding on rice plants after double spray with 00 ppm imidacloprid was significantly higher than control , increasing by 00 . 0 and 000 . 0% , respectively , compared with a single spray and the control . Moreover , hormone levels in the larvae were related to the application method of imidacloprid . JH level in fourth instars after root application and topical application of imidacloprid was significantly lower than in control . 