大豆根内胞囊线虫发育进程及分布

 【目的】明确山东大豆胞囊线虫在大豆根系内的发育进程和动态分布为该病的防治提供最佳防控区域和最佳防治时期,于2007年和2008年对大豆根内胞囊线虫(4号生理小种)进行发育进程及动态分布的监测。【方法】采用网袋法收集根系,酸性品红-次氯酸钠法对根染色,体视显微镜下统计根内各龄期线虫数量。【结果】两年大豆根内胞囊线虫密度呈相同趋势,均为“S”型变化。二龄幼虫(J2)、三龄幼虫(J3)和四龄幼虫(J4)的动态发育规律一致,出苗后4～5周出现峰值,各龄期幼虫在不同土层均有分布,主要集中在5～15 cm土层根系内,均以J2为优势虫态。【结论】在山东省土壤平均温度为20～22.2℃的条件下,大豆胞囊线虫第1个世代需22～35 d的时间,完成1个生活史最短需22 d。防治该病的药效持续期为出苗后1个月左右,作用范围集中于5～15 cm土层。

Distribution and Developmental Process of Heterodera glycines in Soybean Root

【Objective】 Dynamic distribution and developmental process of race 4 of Heterodera glycines (soybean cyst nematode, SCN) in the soybean root were monitored under field conditions in Shandong province during 2007 and 2008 in order to determine the developmental process and distribution of nematodes in soybean root, and provide information for effectively controlling the disease. 【Method】 The root systems were collected with mesh bag method and nematodes in root were stained by the method of fuchsin acid–NaCIO. The nematodes (including different stage juveniles) were counted under stereo microscope. 【Result】 The results of two years indicated that Np (nematodes per cm root) showed the similar sigmoid curve during 37 days of seedling age. The dynamic of development of the second-stage juveniles (J2), the third-stage juveniles (J3) and the fourth-stage juveniles (J4) were similar during the period of the experiment. The highest value of nematode density appeared at 4-5 weeks after soybean seedling emergence. All stage juveniles were distributed at different soil layers but mainly at 5-15 cm soil layer and J2 was the dominant population in each soil layer. 【Conclusion】 Under the average soil temperature around 20-22.2℃ in Shandong province, the first generation of SCN was finished at 22-35 days after soybean seedling emergence and the mature female was found at 22 days. From the results, the chemicals were suggested to be applied on the soil depths of 5-15 cm and lasted for 1 month after soybean seedling emergence and therefore to obtain the effective control of the nematodes..