Abstract: To understand the effects of sublethal dosage of imidacloprid on the experimental population parameter of Aphis craccivora Koch,and to investigate the relationship between the development,reproduction of A. craccivora Koch and sublethal dosage,which can provide a theoretical basis for comprehensive control of A. craccivora Koch. Sublethal dosage of imidacloprid on A. craccivora Koch was examined by leaf with insect dipping method and disc leaf dipped method respectively under constant temperature（25±1） ℃,a 16∶8（L∶D） hours photoperiod and relative humidity（70%~80%）. The developmental duration,fecundity of aphids and life time were recorded. The results showed that mean longevity and fecundity of the adults treated by LC₃₀ were significantly lower than the control,but the mean longevity and fecundity of the adults treated by LC₂₀ and LC₁₀ showed no significant difference than the control. No significant regulations were found on the durations of different developmental stages of F₁ generation nymphs and adults,but the survival rate of F₁ generation nymphs were significantly lower than the control treated by three concentrations（LC₁₀,LC₂₀ and LC₃₀）. The results indicated that the lifetime and fecundity of A. craccivora Koch treated by different concentrations of imidacloprid were inhibited.

Key words: Aphis craccivora Koch, imidacloprid, sublethal effect, growth and development