关键词: 石家庄, 石家庄, 园林绿地, PM₁₀, PM_2.5, 滞尘, 健康效益

Abstract: We aim to solve the problem of slow breeding rate due to the low temperature in Nanxiong tobacco area in spring, using tobacco seedling floating system to breedMyzus persicae andAphidius gifuensis . In this study, floating seedling system was used to breed white radish, andM. persicae was simultaneously inoculated withA. gifuensis . The results showed that white radish seedlings needed 24.5 days to reach the five-leaf stage, while the tobacco floating seedlings needed 49.5 days. When the white radish seedlings reached the three-leaf stage, inoculation with 15-20 heads ofM. persicae for each seedling resulted in the best breeding effect forA. gifuensis , with the total number ofM. persicae per plant up to 125.5 heads after 20 days, and 145.5 heads after 25 days. When inoculated with 30 heads ofM. persicae per plant, yield ofA. gifuensis was the maximum (152.5 heads) after 20 days, but decreased obviously on day 25. In conclusion, when the white radish floating seedlings were at three- or four-leaf stage, inoculating 15-20 heads ofM. persicae with 40%A. gifuensis parasitism rate per seedling would result in high yield ofA. gifuensis . Moreover, the whole breeding period ofA. gifuensis would be shortened by 20-25 days. This method simplifies the breeding process and reduces the breeding cost.