Abstract: 【Aim】 This study aims to ascertain the effect of drought during the root nourishing period of Chinese chives on the population dynamics of the chive gnat, Bradysia odoriphaga. 【Methods】 The number of adults of the F₁ generation of B. odoriphaga occurring in Chinese chives cultured in sandy soil and loamy soil under drought stress for 15, 20, 25 and 30 d was investigated by controlled irrigation to control the soil moisture, and the effect of drought stress on the population parameters of F₁ generation of B. odoriphaga was analyzed by two-sex life table method. 【Results】 The results showed that the occurrence of the adults of F₁ generation of B. odoriphaga fed on Chinese chives cultured in sandy soil and loamy soil were both restrained by drought. As the duration of drought stress increased, the number of B. odoriphaga adults obviously decreased. The number of B. odoriphaga adults was the lowest at 30 d after exposure to drought stress, and the number of B. odoriphaga adults emerged in loamy soil or sandy soil was only one and significantly different from those for other stress duration (15, 20 and 25 d). The duration of the 1st, 2nd, 3rd and 4th instar larva, the duration of immature stage, the preoviposition period and the total preoviposition period of adult female of the F₁ generation of B. odoriphaga exposed to drought stress for 30 d were significantly prolonged as compared with those in the control group, being prolonged by 0.82, 2.53, 2.82, 0.68, 6.32, 1.36 and 8.69 d, respectively, while the net reproductive rate (R₀), intrinsic rate of increase (r_m) and finite rate of increase (λ) were all significantly lower than those of the control, dropping by 32.38%, 37.50% and 5.13%, respectively, as compared with the control. 【Conclusion】 Drought treatment applied to Chinese chives during the root nourishing period can effectively alleviate the occurrence of B. odoriphaga.

Key words: Bradysia odoriphaga, drought, sandy soil, loamy soil, soil moisture content, population dynamics