烟草苗移栽后室内与田间根结线虫幼虫侵染动态检测

Determination of Infection Dynamics of Root-knot Nematode Juveniles after Tobacco Seedling Transplantation in Laboratory and Field

【目的】根结线虫是烟草栽培中引发严重损失的重要病原,移栽初期易受多种根结线虫的侵染。检测植烟土壤中病原种群、侵染动态、二龄幼虫(J2)的数量,便于有效防控该病害。【方法】2013年秋采烤烟叶结束后采集病株根系和根际土壤,通过烟株根结中雌虫会阴花纹显微观察分析花生根结线虫、爪哇根结线虫和南方根结线虫的种群比例;利用采集的病圃土用于室内烟苗移栽,从移栽后第6天开始至21 d检测幼虫侵染入根系的动态。进一步将室内检测结果与2014年在病圃烟田移栽后检测的侵染动态结果进行比较。【结果】病株根结内检测到根结线虫3个种群:花生根结线虫(52.6%),爪哇根结线虫(31.6%)和南方根结线虫(15.8%)。移栽烟苗前田间土壤50 m L中的平均J2数量为8.4条。检测了室内和田间移栽烟苗后的6~21 d根组织内J2,室内侵染高峰期所需的时间较短,且侵染率显著高于田间试验。【结论】烟田病圃中存在3种根结线虫,移栽烟苗前病圃土壤中仍检测到J2平均8.4条/50 m L,室内与田间移栽烟苗后J2侵入根组织内的时间较早。

[ Objective] Root-knot nematodes are important patbogens causing serious yield losses in tobacco. The early stage after transplanta- tion is especially sensitive for infection with Meloidogyne species. In order to control effectively the nematode disease, it is necessal7 to deter- mine tbe population structure and dynamic as well as to calculate tbe titer of second stage juveniles （J2） over time. [ Metbod] After barvest of tbe tobacco leaves in autmnn 2013 infected plants and their rhizospere soil were sampled. The percentage of the three Meloidogyne species M. arenaria, M. javanica and M. incognita was determined by observing the perineal pattern of the female tail. Soil from the provocation field was used for lab-cultivation of young tobacco seedlings. Infection dynamic was followed from 6th to 21 st day after transplantation of to- bacco seedlings and the results were compared with the infection dynamic of the root-knot nematodes in 2014 in the original tobacco field. [ Result] Tbree populations of root-knot nematode species were detected in tbe plant root galls： M. arenaria （52.6 % ） , M. javanica （31.6 % ） and M. incognita （ 15.8 % ）. J2 in tobacco root tissue was counted from 6th＇ to 21st day after transplantation in lab and field. The infec- ted crest-time in lab test was shorter and the infection rate was higher than in the field trial. [ Conclusion ] Three different Meloidogyne species were found in a nematode provocation tobacco field. The average of 8.4 J2/50mL soil was still detected in the soil before transplanting tobacco seedlings. The infection of J2 larvae into tobacco root tissue happened very early in field trial and lab test.