 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 . 