玉米线虫矮化病病原鉴定

为明确东华北春玉米区暴发的一种危害严重、引起玉米植株矮化的新病害病原,从病区采集大量病株及其根际土壤,采用室内人工接种的方法对分离频率最高的3种镰孢菌,即亚粘团镰孢菌Fusarium subglutinans、拟轮枝镰孢菌F.verticillioides和层出镰孢菌F.proliferatum及线虫(群体)进行致病性测定。结果表明:有线虫(群体)的处理能够引起该病害典型症状,即植株矮化,叶片上有沿叶脉方向的黄色或白色失绿条纹,茎基部组织从内向外呈纵向或横向开裂,推断该病的发生和线虫有关。将回接发病植株病土中分离的矮化线虫属Tylenchorhynchus sp.、短体线虫属Pratylenchus sp.、发垫刃线虫属Trichotylenchus sp.、拟盘旋线虫属Pararotylenchus sp.、小环线虫属Criconemella sp.、垫刃线虫属Tylenchus sp.、丝尾垫刃线虫属Filenchus sp.、螺旋线虫属Helicotylenchus sp.和真滑刃线虫属Aphelenchus sp.进行分属后再回接,只有发垫刃属线虫的处理出现与田间发病症状一致的植株。综合形态特征、致病力和分子序列分析结果,确定该病病原为长岭发垫刃线虫T.changlingensis,并将该病害称为玉米线虫矮化病(maize nematode stunt disease)。

Identification of the pathogen causing maize nematode stunt disease

To identify the pathogen causing stunt on maize, a newly found serious disease in northern and northeastern China maize spring-sowing areas, the infected plants and their rhizosphere soil were collected from the disease regions. The pathogenicity of three species with higher isolation frequency, including Fusarium subglutinans, F. verticillioides and F. proliferatum, and nematodes from infected tissues and soil were tested with the inoculation method. The results showed that the treatments with nematodes induced typical symptoms, and dwarf plants grew; the diseased leaves had yellow or white stripes along the veins of leaf, and the stems cracked from inside to outside. All these findings indicated that there existed some relationships among the disease and nematodes. Tylenchorhynchus sp., Pratylenchus sp., Trichotylenchus sp., Pararotylenchus sp., Criconemella sp., Tylenchus sp., Filenchus sp., Helicotylenchus sp. and Aphelenchus sp. re-isolated from soils collected from plants with typical symptoms in pathogenicity tests were inoculated independently. The results showed that only the treatments of Trichotylenchus sp. induced typical symptoms. Based on the morphological, morphometric, molecular characteristics and pathogenicity test, the nematode reported here was identified as T. changlingensis. The disease was named maize nematode stunt disease.