甜菜孢囊线虫在我国的寄主范围及生活史研究

甜菜孢囊线虫Heterodera schachtii是严重危害甜菜生产的主要病原物,每年造成严重的经济损失,该线虫是我国对外重要的检疫性有害生物。本研究通过对十字花科、茄科、葫芦科、锦葵科、豆科、苋科和禾本科等16种作物29个品种进行人工接种,对其主要的寄主范围和生活史进行了测定。结果表明,甜菜孢囊线虫2龄幼虫能够侵染除小麦和玉米以外的其他14种作物25个品种,在苋科的甜菜和菠菜、茄科的番茄及十字花科等16个品种的根系能够完成生活史,形成白雌虫和孢囊。生活史调查发现,甜菜孢囊线虫接种到甜菜和油菜15 d和12 d后即可发育形成白雌虫,30 d后形成孢囊;而接种到西瓜根系后,不能正常发育,一直保持2龄幼虫虫态,无法完成生活史。上述结果表明甜菜孢囊线虫能够在甜菜、菠菜、番茄和十字花科作物上寄生,但是在不同寄主上的生活史存在一定的差异,其结果将为非寄主轮作防控甜菜孢囊线虫提供理论基础。     

警惕检疫性有害生物马铃薯孢囊线虫(Globodera rostochiensis和G. pallida)入侵我国

马铃薯孢囊线虫包括马铃薯金线虫Globodera rostochiensis和马铃薯白线虫G. pallida, 是马铃薯生产上危害最为严重的植物寄生线虫, 一般造成30%的产量损失, 在热带发病严重地区, 产量损失高达80%~90%, 甚至绝收?由于其危害严重性, 包括我国在内的100多个国家将其列为重要检疫性有害生物?我国目前尚无马铃薯金线虫和白线虫的发生报道, 但随着贸易全球化, 马铃薯孢囊线虫传入我国的风险日趋增高?本文主要对马铃薯孢囊线虫的发生分布?危害症状?经济损失?生物学特性?传入我国的潜在风险和预防控制措施进行综述, 旨在为防止马铃薯孢囊线虫入侵我国提供参考?     

马铃薯孢囊线虫分子检测技术研究进展

马铃薯孢囊线虫是世界级重要的检疫性有害生物,可危害马铃薯并造成重大的经济损失。早发现早防控,对保护马铃薯产业的健康发展极其重要。本文对马铃薯孢囊线虫的现有分子检测技术进行了综述,分析了各种检测技术在马铃薯孢囊线虫检测中的优缺点,为开发适合于田间快速检测的新技术提供参考。     

南通狼山风景区针叶树线虫疫情调查

前言松材线虫Bursaphelenchus xylophilus是我国禁止入境的植物二类危险性有害生物,在我国江苏等地区局部分布.因其对以松属为主的针叶树木造成的毁灭性危害,为防止松材线虫从境外传入,近年来我国检验检疫机关对来自松材线虫疫区的进境木质包装材料加强了检疫工作,并多次截获松材线虫.     

菊花滑刃线虫及其检测和防疫方法

菊花滑刃线虫（Aphelenchoides ritzemabosi）是一种重要的植物寄生线虫,可寄生为害数百种植物,导致植物降低或失去经济价值,严重时导致植物落叶枯死.该线虫随着寄主植物繁殖材料和鲜切花进行远距离传播,被许多国家和地区列为检疫性植物有害生物,我国于2006年将其列为全国农业植物检疫性有害生物.本文描述了该线虫的形态鉴定特征、在国内外发生危害情况及其生物学和病理学特性,并介绍了该线虫的检测和防疫方法及措施.     

香蕉穿孔线虫及其检测和防疫控制

香蕉穿孔线虫（Radopholus similis）是国际公认的重大植物检疫性有害生物，寄主范围广，对多种经济植物造成严重危害。其主要侵染植物的根部和球茎等地下组织，具有很强的适生能力，极易随着寄主植物苗木及其粘附的土壤传播，目前已传播扩散到全世界90多个国家或地区，给当地的种植业生产和贸易造成严重危害和损失。近几年，该线虫随着观赏植物的引进传入中国，在温室和大棚的观赏植物上发生危害，造成重大经济损失。因此，加强对该线虫的检测和防疫控制，阻止其进一步传入、扩散和危害，是防止该线虫疫病在我国爆发成灾的重要举措。     

玉米孢囊线虫发生危害和生物学研究进展

玉米孢囊线虫Heterodera zeae Koshy,SwarupSethi,1971年在印度的拉贾斯坦邦第一次被发现并报道。虽然该病在我国未见相关报道,但我国是世界上玉米生产大国,种植面积已达到世界第二位,分布范围广。因此,对该病害的了解具有重要意义。本文主要介绍国外有关玉米孢囊线虫的研究进展,包括玉米孢囊线虫病的症状、病原形态特征、危害情况、寄主范围及其生物学特性等方面。为防止玉米孢囊线虫在我国发生危害和扩散提供参考信息。     

潜在外来入侵甜菜孢囊线虫在中国的适生性风险分析

本文应用MAXENT与GARP两种生态位模型对甜菜孢囊线虫在中国的适生性进行了风险分析和预测。结果表明甜菜孢囊线虫可在中国17个省市生存,适生范围为26°N～48°N,77.6°E～136°E。甜菜孢囊线虫入侵的高风险区:内蒙古南部、新疆西部、河北中南部、山西东北部、宁夏、甘肃北部;中风险区:北京、天津、陕西、山西大部、内蒙古西部和东南部、吉林西部、新疆北部;低风险区:河南、陕西南部、山东、内蒙古中东部、新疆中部、辽宁、吉林大部、黑龙江南部、江苏、安徽、湖北、湖南、江西、浙江北部;而青海、新疆南部、西藏、四川、重庆、云南、贵州、广西、广东、福建、海南、内蒙古少数地区和黑龙江部分地区属于基本不发生区。我国内蒙古、新疆、辽宁等省市甜菜种植区均适合甜菜孢囊线虫发生,对上述地区的进出口岸应加强甜菜孢囊线虫的检疫工作。     

潜在外来入侵甜菜孢囊线虫在中国的适生阵风险分析

本文应用MAXENT与GARP两种生态位模型对甜菜孢囊线虫在中国的适生性进行了风险分析和预测。结果表明甜菜孢囊线虫可在中国17个省市生存,适生范围为26°N～48°N,77．6°E～136°E。甜菜孢囊线虫入侵的高风险区：内蒙古南部、新疆西部、河北中南部、山西东北部、宁夏、甘肃北部;中风险区：北京、天津、陕西、山西大部、内蒙古西部和东南部、吉林西部、新疆北部;低风险区：河南、陕西南部、山东、内蒙古中东部、新疆中部、辽宁、吉林大部、黑龙江南部、江苏、安徽、湖北、湖南、江西、浙江北部;而青海、新疆南部、西藏、四川、重庆、云南、贵州、广西、广东、福建、海南、内蒙古少数地区和黑龙江部分地区属于基本不发生区。我国内蒙古、新疆、辽宁等省市甜菜种植区均适合甜菜孢囊线虫发生,对上述地区的进出口岸应加强甜菜孢囊线虫的检疫工作。     

应用TaqMan探针进行马铃薯金线虫实时荧光PCR检测技术研究

马铃薯孢囊线虫是全球性的植物检疫性线虫,亦是我国重点关注的有害生物。针对马铃薯金线虫ITS序列,设计了引物和TaqMan 探针,使用15个马铃薯孢囊线虫群体和4个其他孢囊线虫样品进行验证,可高度灵敏地检测单个马铃薯金线虫的孢囊或幼虫,并可进行定量;最高检测灵敏度达到10fg;同时开展了混合样品和未知样品的检测,证明了引物的专化性和TaqMan探针的特异性。该检测方法可自动化检测马铃薯金线虫并进行定量,适合进行标准化的常规检测。     

Computer mapping of records of beet cyst nematode (Heterodera schachtii), 1928–77

Early records of beet cyst nematode ( Heterodera schachtii Schmidt) in Britain and the history of regulatory measures to control it are summarized. Data collected between 1928 and 1976 were computer mapped on a 10 km grid scale to illustrate the cumulative distribution of beet cyst nematode in Britain. The distribution of the nematode was compared with that of its principal host, sugar beet. Data collected between 1962 and 1977 in East Anglia were computer mapped on a 1 km grid scale to show the detailed distribution of beet cyst nematode in that area. The advantages of computer-generated distribution maps over manually produced maps are discussed.     

Assessment of Host-Induced Selection on Three Geographic Isolates of Heterodera schachtii Using RAPD and AFLP Markers

ABSTRACT The hypothesis that host plants exert selection pressure on Heterodera schachtii populations was tested. Host selection of genotypes from three genetically distinct isolates of H. schachtii was assessed using cabbage, sugar beet, oilseed radish (Raphanus sativus), and white mustard (Sinapis alba). The plants represent a range of susceptibility to H. schachtii and included R. sativus and S. alba, because cultivars of those species have been used as trap crops for H. schachtii in Europe. Genotypic differences in amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) markers were detected among the isolates after they reproduced on the different hosts. The poorest host plant, R. sativus, resulted in the greatest number of changes in both AFLP and RAPD markers. Oilseed radish selected nematode genotypes in less than four nematode generations. The nematode population genotypes detected by RAPD analyses after selection on oilseed radish were observed even after nematode populations were transferred back to the other three hosts. The genetic markers that were detected after selection were influenced by the genotypes of the original nematode isolates. The results indicate the utility of RAPDs and AFLPs for identifying and monitoring intraspecific genetic variability in nematodes and for understanding nematode population responses to host plants. Nematode management practices such as using resistant cultivars may alter gene frequencies, thereby reducing the efficacy of the tactic and exacerbating the nematode's potential to damage subsequent crops.     

Induction of Beet-Cyst Nematode Suppressiveness by the Fungi Dactylella oviparasitica and Fusarium oxysporum in Field Microplots

ABSTRACT The ability of Dactylella oviparasitica and Fusarium oxysporum to suppress Heterodera schachtii numbers was examined in field microplots. Fungi were individually added to fumigated field soil that was seeded with sugar beet. Four weeks later, soils were infested with H. schachtii second-stage juveniles (J2). At two harvests, 11 weeks and 19 weeks (1,469 and 2,547 degree days (base 8 degrees C), respectively) after nematode-infestation, H. schachtii cyst and egg numbers were assessed. At both time points, D. oviparasitica reduced H. schachtii population densities to those in the naturally suppressive soil, even when additional H. schachtii J2 were added to the microplots after the first harvest. Although F. oxy-sporum did not alter H. schachtii population densities after 11 weeks, significant reductions were detected after 19 weeks. The sustainability of the H. schachtii suppressiveness created by single applications of the fungi at the beginning of the microplot trials was further examined in a greenhouse study. Soil collected at the completion of the microplot trials was potted and seeded with sugar beet. Four weeks later, each pot was infested with H. schachtii J2. Approximately 16 weeks (1,389 degree days) after seeding, the D. oviparasitica-amended soil produced greater fresh root weights and considerably smaller nematode population densities than the nonamended control.     

Biologische Bek?mpfung des R��benzystennematoden Heterodera schachtii

The beet cyst nematode Heterodera schachtii is widely spread among sugar beet habitats with narrow crop rotation (especially in the warmer region of the Rhine Gorge). Without a consistent control management the economic efficiency of sugar beet cultivation under the current framework requirements is threatened. This problem is solved by the biological control using nematode-resistant oil radish or mustard which has been established during the last 25 years. Population of nematodes can be reduced up to 70% while maintaining the sugar beet yield on a high level. Big plot studies achieved a yield increase of 10?C15% thereby confirming the economic efficiency of nematode control measures using resistant undersown crops. Another starting point for problem solving lies within the cultivation of nematode-resistant sugar beet varieties. Currently, the sugar content and sugar yield of these varieties lie below the level of the standard varieties. Without nematode infection reduction in grain yield of approximately 10% must be accepted. Thus, cultivation is only economically reasonable in the infection areas. Heterodera schachtii is decreased by 60?C70%. Breeding of nematode-resistant sugar beet varieties has been the last step up to now. Already with low latent nematode infection these varieties clearly outbalance previous grain yields. A study series in 2009 showed an increase in sugar yield by an average of 10?C18% compared to the normal variety by cultivation of tolerant beet with latent nematode infection. Despite further developments in control management of tolerant/resistant beet, the culturing of resistant undersown crops remains up to date as these varieties, although only to a small degree, suffer from Heterodera schachtii.     

Surveys of beet cyst nematode in England 1977–80

Surveys of sugar beet crops for beet cyst nematode ( Heterodera schachtii Schmidt) in seven selected areas of England have provided data on distribution of the pest and on some factors affecting its occurrence. These data were mapped by CAMGRID computer program.
Infestations occurred mostly on the East Anglian fenland (14% of fields infested) and in this area were more frequent nearer the sugar beet processing factory. In the remaining areas the few infested fields (5% or less) were generally scattered but a small concentration of infestation occurred in the West Midlands in an area of intensive horticulture with frequent brassica crops. The survey data did not support the view that beet cyst nematode infestations occur more frequently near access points to the crop. In the surveyed areas frequency of host crops appears to be more important than soil type in determining the likelihood of infestation.     

PCR zum halbquantitativen Nachweis von Rübenzystennematoden

Increased crop yield of nematode resistant sugar beet varieties compared to non-resistant varieties is dependent upon density of the sugar beet nematode, Heterodera schachtii, being below a certain threshold level. Therefore there is a requirement for an inexpensive quantitative laboratory test for H. schachtii. Currently the standard method to determine nematode densities relies on extraction of cysts from soil samples and their subsequent enumeration which is time-consuming. The method described in this article involves the extraction of nematodes obtained by a technique inducing the hatching of juveniles. Hatching of larvae is induced by incubation of the soil sample with “Acetox” followed by a Baermann funnel extraction. Instead of a visual estimation of nematode densities using a microscope, H. schachtii larvae are identified by a molecular diagnostic. The aim of this study is to distinguish between the three threshold infestation levels by comparing the intensities of PCR products derived from samples containing known numbers of target H. schachtii.     

Rice nematode problems in Nigeria: Their occurrence,distribution and pathogenesis

Abstract

In a survey of plant parasitic nematodes associated with or affecting rice throughout Nigeria, some important nematode pests, especially the white tip disease nematode, Aphelenchoides besseyi and the rice root nematodes Hirschmanniella spinicaudata and H. oryzae were identified from seed, soil and root samples from swamp rice fields respectively. The sugarcane cyst nematode, Heterodera sacchari occurred in swamp rice fields only around the major sugarcane estates in Nigeria. The root‐knot Meloidogyne incognita and the root lesion nematode, Pratylenchus brachyurus were also encountered in upland (rainfed) rice fields. The white tip disease nematode, A. besseyi occurred at low levels in soils and rice seeds throughout the country. High population levels of H. spinicaudata and H. oryzae were encountered especially in areas where monoculture of rice is practised. General chlorosis, poor tillering and significantly reduced yield have been observed due to H. spinicaudata. Rice plants attacked by H. sacchari also showed intense chlorosis, delayed and reduced tillering and reduced grain yield. The roots of attacked plants were twiggy, very necrotic and blackened. The root‐knot M. incognita and the root lesion nematodes P. brachyurus have both been observed to reduce rice yields. Rice cultivars screened for reactions to the nematodes showed varying degrees of susceptibilities. Some varieties were however resistant to the root‐knot nematode, M. incognita.