韭菜养根期干旱处理对韭菜迟眼蕈蚊种群动态的影响

【目的】本研究旨在明确韭菜养根期干旱处理对韭菜迟眼蕈蚊Bradysia odoriphaga种群动态的影响。【方法】通过控制浇水调控土壤含水量，调查15, 20, 25和30 d干旱胁迫下砂土和壤土栽培的韭菜中韭菜迟眼蕈蚊F1代成虫的发生量，并通过两性生命表方法分析干旱胁迫30 d对韭菜迟眼蕈蚊F₁代种群参数的影响。【结果】研究结果表明，不论砂土还是壤土，干旱胁迫均抑制了韭菜迟眼蕈蚊F1代成虫的发生: 随干旱胁迫时间的增加，韭菜迟眼蕈蚊成虫的数量显著下降；其中干旱胁迫30 d时，韭菜迟眼蕈蚊成虫的发生量最低，壤土或砂土中的F₁代成虫羽化量仅为1头，与其他干旱胁迫时间(15, 20和25 d)相比发生量差异显著。经历30 d干旱胁迫的韭菜迟眼蕈蚊F₁代1, 2, 3和4龄幼虫发育历期、未成熟期、雌成虫产卵前期和总产卵前期较对照组显著延长，分别延长0.82, 253, 2.82, 0.68, 6.32, 1.36和8.69 d，而净生殖率(R₀)、内禀增长率(r_m)以及周限增长率(λ)则显著低于对照组，分别较对照组下降32.38%, 37.50%和5.13%。【结论】在韭菜养根期进行干旱处理可有效抑制韭菜迟眼蕈蚊的发生。

Effect of drought during the root nourishing period of Chinese chives on the population dynamics of the chive gnat,Bradysia odoriphaga (Diptera: Sciaridae)

【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.