栀子根结线虫病的病原鉴定

为明确广西贺州市栀子根结线虫病病原种类,采集根部有明显根结的栀子根系进行根结线虫分离鉴定,通过观察根结线虫2龄幼虫、雌成虫、会阴花纹特征对其进行形态学鉴定,并利用核糖体ITS区和28S rDNA D2D3区序列比对和系统发育树分析方法对其进行分子生物学鉴定。结果表明,该病原线虫2龄幼虫和雌成虫形态特征及形态测量值与象耳豆根结线虫（Meloidogyne enterolobii Yang & Eisenback, 1983）相似;该病原线虫核糖体ITS区与NCBI数据库中象耳豆根结线虫相应序列的相似度为100%,28S rDNA D2D3区与NCBI数据库中象耳豆根结线虫相应序列的相似度为99%以上;该病原线虫核糖体ITS序列以99%的支持率与象耳豆根结线虫聚为同一分支。综合形态学和分子生物学鉴定结果将广西贺州市栀子根结线虫病病原种类鉴定为象耳豆根结线虫,栀子（Gardenia jasminoides Eills）是该线虫的新寄主纪录。     

福建省香蕉根结线虫病调查与病原鉴定

2008~2013年,在福建省漳州市进行香蕉根结线虫病害的分布和危害性调查,结果表明：香蕉根结线虫病发生普遍,田间香蕉的株发病率达79.3％,苗圃香蕉假植苗株发病率达94.8％,带病香蕉苗成为香蕉根结线虫病的重要侵染源。香蕉根结线虫病的病原种类鉴定结果为南方根结线虫（Meloidogyne incognita）、爪哇根结线虫（M. javanica）和花生根结线虫（M. arenaria）,南方根结线虫为优势种,且存在根结线虫的混合种群。     

水稻根结线虫病的病原鉴定及其侵染源的研究

 在福建省政和县稻田发现大面积的严重水稻根结线虫病,沟渠内禾本科杂草油芒(Eccoilopus sp.)也遭受根结线虫（Meloidogyne   sp.）的严重侵染。这两种寄主的根结线虫形态特征与拟禾本科根结线虫(Meloidogyne graminicola,Golden and Birchfield,1965)原始描述相符;对根结线虫的rDNA ITS区、28S rDNA D2/D3区进行了扩增、克隆与测序,其序列与GenBank中拟禾本科根结线虫的相似性达99%以上,据此将水稻和油芒上的根结线虫鉴定为拟禾本科根结线虫。通过交叉接种试验和田间调查,证实油芒是水稻根结线虫的重要寄主,为田间水稻根结线虫病的重要侵染源。      

寄生于根结线虫卵囊的绮丽小克银汉霉

从发生根结线虫病害的丝瓜、柑桔、水蜜桃等作物的根上的根结线虫卵囊上分离获得6株绮丽小克银汉霉（Cunning-hamella elegansLendner）。接种试验证实这些分离物可寄生南方根结线虫的卵。     

麦类作物线虫病的研究现状及对策

本文阐述了麦类作物主要线虫病及其有关症状、发生规律等新的研究进展。研究指出小麦粒瘿线虫对寄主有特异性识别作用.侵染后寄主的新陈代谢受到干扰。粒瘿线虫、燕麦孢囊、根结、根腐等线虫.可与细菌、真菌造成复合侵染加重为害。它们大都存在生理分化现象,轮作与抗病育种时应予以注意。穿刺巴氏芽孢杆菌、厚垣孢轮枝菌、嗜雌线疫霉菌对燕麦孢囊和根结线虫的雌虫和卵有一定生防作用.可进一步研究应用。     

旱稻孢囊线虫生活史及侵染特性

 以2龄幼虫人工接种水稻幼苗和田间定点调查的方法,研究了旱稻孢囊线虫的生活史和侵染特性。结果表明,在30℃下接种后24 h内,2龄幼虫大多聚集在根尖分生区或伸长区,接种后24 h可侵入根系,侵入后虫体在中柱建立取食点;接种后6 d,2 龄幼虫发育成白雌虫,8 d发育成雄虫,12 d雌虫从阴门处产生胶状物质,雌虫的一部分卵产于胶质卵囊中。接种后18 d,胶质卵囊中的2龄幼虫开始孵化。在30℃下,旱稻孢囊线虫从卵到卵的最短生活周期为22 d;从接种到2龄幼虫从胶质卵囊中孵出,最短生活周期为18 d。20℃下线虫发育缓慢。较高温度如28℃~35℃有利于2龄幼虫的侵染和发育。淹水条件不利于2龄幼虫的侵染,但对孢囊的发育无显著影响。     

红麻根结线虫病综合防治研究

在湖南、湖北、广东、广西、浙江和河南等省(区)主产区调查和鉴定,红麻根结线虫病病原线虫有南方根结线虫(Meloidogyne incognita)1号和2号小种,爪哇根结线虫(M.javanica)和花生根结线虫(M.arenaria)2号小种。南方根结线虫为优势种,其在湖南沅江麻田一年可完成四代。它们都不为害棉花、小麦、花生、芝麻、苎麻、高粱和玉米。幼虫主要分布在0～40厘米土层内。0～10厘米土层内幼虫数的波动在红麻生长季节有4个高峰,收获后还出现一个高峰。病原线虫以幼虫和卵主要在病残中越冬,清除病残可压低初次侵染。实行轮作可减轻病害和增产。重病田用D—D混剂,涕灭威或棉虫灵处理土壤效果良好。文中对抗线虫育种工作作了讨论。     

胞囊线虫侵染不同抗性大豆品种根系的组织病理学差异研究

为明确对大豆胞囊线虫病具有不同抗性的小黑豆品种的抗性机制,利用石蜡切片技术对线虫侵染不同抗性大豆品种根系的组织病理学差异进行了研究。结果表明:在侵染初期,抗感品种侵入根内的线虫数量没有明显差异,抗病品种形成合胞体的时间要早于感病品种辽豆15,哈尔滨小黑豆较早地在中柱内形成了合胞体,抗侵入能力较弱。随着线虫的侵染,抗病品种逐渐形成过敏性坏死反应,阻止线虫发育使根内形成非常少量的雌虫,其中灰皮支黑豆根内几乎没有雌虫形成,抗发育能力最强。感病品种辽豆15根内没有发生过敏性坏死反应形成了大量雌虫。在寄主维管束中,侵染后期中柱内形成的合胞体会使感病品种辽豆15木质部外移,根内导管数量减少,不利于水分运输的安全性。而3个抗病品种小黑豆的木质部组织结构没有发生病变,利于大豆的正常生长。     

穿刺巴斯德芽菌PPh01菌株鉴定及其对根结线虫的寄生性测定

从海南定安胡椒根部根结线虫体上分离到一株细菌PPh01,其形态特征与穿刺巴斯德芽菌相似。16S rDNA序列分析结果表明：该菌株与穿刺巴斯德芽菌的同源性达到99.3％,在发育树上聚为同一分支,亲缘关系最近,鉴定该菌株为穿刺巴斯德芽菌（Pasteuria penetrans）。寄生性试验结果表明：该菌株对南方根结线虫、爪哇根结线虫、花生根结线虫的2龄幼虫均具有寄生性和侵染能力。     

中国大豆根结线虫病(Meloidogyne incognita;M.arenaria;M.hapla)病原鉴定及地区分布

本研究鉴定出在中国大豆上又一类重要病原线虫——根结线虫。黄淮海豆区为其主要发生危害地带,并且,其主要病原种和小种为南方根结线虫寄主小种1号和花生根结线虫寄主小种2号。经用光学显微镜和扫描电子显微镜形态学观察,测量及鉴别寄主试验鉴定,结果表明其区系分布大体为:在开封为南方根结线虫[Meloidogyne incognita (Kofoid and White,1919) Chitwood,1949]寄主小种1号和花生根结线虫[M.arenaria (Neal,1889) Chitwood,1949]寄主小种2号;在宁陵为花生根结线虫寄主小种2号;在崂山为南方根结线虫寄主小种1号,在栖霞为北方根结线虫(M.hapla Chitwood,1949),其中南方根结线虫的开封群体和崂山群体雌虫会阴花纹和排孔位置略有不同,但仍属于其种内群体及个体之间的差异。     

出口盆栽榕树根结线虫病的发生与防控药剂选择

以出口盆栽榕树种植示范基地为观测点,剖析检测根结线虫病的病原种类、为害症状、发病规律和传播控制,选择测定阿维菌素、毒死蜱、益舒宝和克百威对基质和根系根结线虫的防控效果,评价根结线虫对这4种药剂的敏感性。结果表明:对出口盆栽榕树造成为害的主要是南方根结线虫。阿维菌素原浆、毒死蜱乳油对盆栽榕树基质和根系根结线虫的防控效果均较理想,极显著优于两颗粒剂益舒宝和克百威。基质根结线虫对阿维菌素和毒死蜱敏感,LD50分别为0.215 4 mg/L和0.215 5 mg/L,无明显差异。根系根结线虫对阿维菌素的LD50为8.64 80 mg/L,是毒死蜱的3.10倍;克百威的LD50为2.127 9 g/盆,是益舒宝的1.35倍;各处理抗性个体出现频率会有不同,要尽可能轮换或交替使用。     

Response of selected cucumber cultivars to Meloidogyne incognita

Root-knot nematodes (Meloidogyne spp.) are one of the most destructive pathogens of vegetables. The cultivars resistant to root-knot nematodes have comparatively better crop yield than susceptible varieties and can be employed as a component of integrated nematode management. In the present study, 15 cultivars of cucumber (Cucumis sativus) were tested for their response to Meloidogyne incognita by inoculating with 3000 2nd stage juveniles of the nematode. All cultivars varied significantly in causing reductions in growth parameters over their controls. Likewise, all cultivars behaved differently regarding formation of galls and egg masses and reproductive factor. It was found that none of the tested cultivars was found immune or highly resistant. Long Green was the only cultivar which was found resistant against M. incognita as it showed minimum galls (8.2) and reductions in growth parameters. On the other hand, cultivars Mehran, Mirage, Thamin-II, and Royal Sluis were highly susceptible as evident by maximum galls (>100) on their roots and reductions in growth parameters. Similarly, the cultivars Green Wonder, Cucumber Citriolo and Poinsett were moderately susceptible (31–70 galls) while Babylon, Cobra and Falcon-560 (71–100 galls) were susceptible and reductions in growth parameters of these cultivars were less than those in highly susceptible cultivars. Four cultivars, Marketmore, Dynasty, Pioneer-II, and Summer Green, were rated as moderately resistant (11–30 galls) as these cultivars showed less damage by the nematode than moderately susceptible, susceptible and highly susceptible cultivars.     

Evaluation of resistance to root-knot nematode (Meloidogyne incognita) in okra cultivars

The root-knot nematode, Meloidogyne incognita, is one of the major limiting factors affecting plant growth and yield causing an estimated $100 billion loss per year worldwide. Synthetic pesticides, though instantaneously effective, are usually prohibitively expensive, not readily available, may cause hazards to both man and livestock, and inflict injury to the environment. Notable among the alternatives to nematicides is the use of resistant cultivars which are inexpensive and eco-friendly. In the present studies, twelve okra (Abelmoschus esculentus L) cultivars were evaluated for their resistance against M. incognita under field conditions. Ten-day old okra plants of test cultivars were inoculated with 3000 freshly hatched second stage juveniles of M. incognita. The nematode caused reductions in various growth parameters of all the cultivars to varying levels over their respective controls. None of the cultivars was found completely resistant. The cultivar ‘Sharmeeli’ was highly susceptible as >100 galls were recorded on the roots. Sharmeeli also showed maximum reductions in growth among the cultivars evaluated. The cultivars Anmol and Sindha were susceptible with 71–100 galls. The cultivars Sabz Pari, Super Star, PMS-55 and PMS Beauty were moderately susceptible with 31–70 galls and comparatively less reductions in growth. Cultivars Sanam, Dikshah, Arka Anamika, Ikra-1 and Ikra-2 with 11–30 galls were rated as moderately resistant and showed less damage by the nematode as compared to susceptible cultivars and their planting could provide a useful tool to control root-knot nematodes.     

福建省蔬菜根结线虫卵囊寄生真菌鉴定

调查了福建省部分地区的蔬菜根结线虫卵囊寄生真菌。从8种蔬菜病根上采集根结线虫卵囊样品624份,分离到真菌401株,除34株不产孢及疑难种未鉴定外,已鉴定的真菌有18个属：镰孢菌、拟青霉、根霉、曲霉、厚垣孢普可尼亚菌、丝核菌、弯孢、毛霉、刚毛孢、木霉、链格孢、拟盘多毛孢、青霉、炭疽菌、黑孢霉、小克银汉霉、枝孢霉、横隔霉。镰刀菌属、曲霉属、木霉属为优势真菌,分别占总分离数的31.2%、10.2%、12.7%;淡紫拟青霉和厚垣孢普可尼亚菌分别占8.1%和4.5%。     

Evaluation of bacterial biological control agents for control of root-knot nematode disease on tomato

Among 19 bacterial strains isolated in Yunnan from rhizosphere soils and plant tissues, Bacillus methylotrophicus strain R2-2 and Lysobacter antibioticus strain 13-6 exhibited the highest antagonistic activity against the tomato root-knot nematode Meloidogyne incognita in plate and greenhouse pot experiments. The two strains, when applied as soil drenches or seed treatments in greenhouse experiments, reduced root-knot severity and incidence on tomato compared to no-bacteria controls. In tomato field trials conducted in separate years, soil drench treatment with either strain reduced root-knot disease levels and increased yields compared to the control. Levels of disease control and yield enhancement provided by the strains were higher than those using the chemicals abamectin and carbofuran. This is the first report of B. methylotrophicus being used as a biocontrol agent against a plant parasitic nematode and the first demonstration that B. methylotrophicus and L. antibioticus can suppress disease caused by root-knot nematodes in the field.     

Histopathological changes induced by Meloidogyne incognita in some ornamental plants

Histopathological changes induced by the root-knot nematode (Meloidogyne incognita) in five ornamental plants, specifically, Calendula (Calendula officinalis), Centaurea (Centaurea montana), Papaver (Papaver somniferum), Chrysanthemum (Chrysanthemum morifolium) and Dianthus (Dianthus caryophyllus), were investigated. Based on the galling index (GI), Centaurea was classified as susceptible, Calendula as moderately susceptible, and Papaver as moderately resistant, while Chrysanthemum and Dianthus were highly resistant to M. incognita infection. The histopathology of the galled roots of Centaurea, Calendula, and Papaver during later stages of infection showed that nematodes were localized entirely within the cortex and generally oriented horizontally to the vascular cylinder. Most of the females were mature, and a few of them were associated with egg masses. Giant cells with a variation in cell sizes were observed in the galled roots of all three of the plant species and exhibited a granular cytoplasm and hypertrophied nuclei as a typical reaction to nematode feeding.