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?     

Effect of benomyl on the potato cyst nematode,Heterodera rostochiensis

Benomyl is a strong fungistat against certain groups of fungi and it does not have much effect on most plant-parasitic nematodes.Heterodera spp., however, are affected, and the literature indicated a strong effect onHeterodera rostochiensis in the field. Laboratory tests demonstrated that hatching of larvae fromH. rostochiensis cysts is strongly inhibited by benomyl in vitro. In a pot trial, benomyl effectively suppressed formation of new cysts on the roots of potatoes grown in sand, clay soil or lightsandy loam. There was no such effect in soil rich in organic matter probably because of strong adsorption of benomyl. Control ofH. rostochiensis by benomyl in soil could be due to suppressed hatch or to other mechanisms, such as inhibition of larval penetration of roots. In view of its long persistence in the soil and of its various side-effects, benomyl does not seem very promising for practical control ofHeterodera rostochiensis.Samenvatting Benomyl is bekend als een middel met sterk fungistatische eigenschappen ten aanzien van bepaalde groepen schimmels. Het heeft in het algemeen weinig effect op planteparasitaire aaltjes. Cystevormende aaltjes echter, en in het bijzonderHeterodera rostochiensis, zijn, volgens aanwijzingen uit de literatuur gevoeliger voor benomyl.Onder laboratoriumomstandigheden bleek het uitkomen van de larven vanH. rostochiensis uit de cysten sterk door benomyl te worden geremd (Tabel 1 en 2). In een potproef werd door een grondbehandeling met benomyl de vorming van nieuwe cysten op aardappelwortels onderdrukt, afhankelik van de grondsoort (Tabel 3). Naarmate de grond meer organische stof of klei bevat, is het effect minder groot. Bijgebruik van rivierzand trad reeds bij een dosering van ongeveer 1 ppm benomyl een volledige on derdrukking van cystevorming op. Maar bij potgrond (59% organische stof) was er, ook bij een tien maal hogere dosering, geen effect. Verder onderzoek zal moeten uitwijzen of het effect in grond, berust op de remming van het uitkomen van larven uit de cysten, of (ook) op de beïnvloeding van andere aspecten van het parasitair gedrag van dit aaltje, zoals de penetratie in de wortels.Gezien de grote persistentie van benomyl in de grond, en de nevenwerkingen, lijkt het middel minder geschikt voor toepassing in de praktijk.Guest worker of TNO, Netherlands Organization of Applied Scientific Research.     

Detection of viable potato cyst nematodes (Globodera rostochiensis and G. pallida) by reverse transcription PCR

Journal of Plant Diseases and Protection - Currently plant infectivity assays (bioassays) seem most reliable to determine viability of potato cyst nematodes (Globodera rostochiensis and G....     

Decline of potato cyst nematodes, Globodera rostochiensis and G. pallida, in spring barley microplots

In microplots of nine soils freed from volunteer potatoes and sown for four consecutive years with spring barley, the eggs of five populations of Globodera pallida and four populations of G. rostochiensis declined at annual rates of 12-8-40-5%. One population of G. rostochiensis declined faster than other populations of either species, although average rates of decline did not differ significantly between the two species of Globodera. These results are compared with earlier research and their relevance to control of the nematodes by crop rotation is discussed.     

The use of plastic bags as closed containers in screening for resistance to potato cyst nematode (Globodera rostochiensis and G. pallida)1

The use of a plastic bag as a closed container to screen for resistance in potatoes to potato cyst nematode in a controlled environment is described. Procedures to standardize the material tested and the inoculum used are outlined and the advantages of the system are discussed.     

The effect of organophosphorus compounds and oxime carbamates on the potato cyst nematode Heterodera rostochiensis woll

The effect of organophosphate and oxime carbamates on the potato cyst nematode, Heterodera rostochiensis was investigated. Although aldicarb slightly delayed emergence of second stage larvae, none of the chemicals decreased total hatch. Aldicarb had a marked effect on second stage larvae in soil which was subsequently reflected in root invasion counts. Comparisons between the initial and final populations (multiplication rate) of the potato cyst nematode are very useful for determining the efficacy of treatment. The evidence from these experiments suggests that organophosphoros compounds and oxime carbamates, although “systemic”, act against plant parasitic nematodes in the soil phase of the life cycle and not in the plant.     

Assessing reproduction of potato cyst nematodes (Globodera rostochiensis and G. pallida) on potato cultivars for National Listing1

To investigate testing procedures for assessing the reproduction of potato cyst nematodes (PCN) on potato cultivars, and to minimize variation in results, trials were done jointly for 3 years at two UK National Listing test centres (DANI in Northern Ireland, DAFS in Scotland). Test clones comprised susceptible, resistant and ‘partially resistant’ cultivars. The factors under investigation included the effect of season, site, location, temperature, PCN population, inoculation method, pot size, hatch rates and methods of assessment of reproduction. Standard procedures are recommended for testing potato cultivars for resistance to PCN.     

Resistance of potato varieties to field populations of the potato cyst nematode Globodera pallida in the northeastern part of the Netherlands

In the northeastern part of the Netherlands starch potatoes are grown intensively. From 392 fields in that area, soil samples that contained the potato cyst nematodeGlobodera pallida were used to analyze the resistance of 7 varieties of starch potatoes.Differences and similarities in resistance of the varieties to the field populations ofG. pallida could well be explained by their descent from distinct sources of resistance.TheG. pallida-populations that showed a relatively high virulence to the varieties Producent, Elles, and Darwina were not equally distributed over the area, but were confined to a small number of regions.     

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。     

Population dynamics of the potato cyst nematode,Globodera pallida,in relation to temperature,potato cultivar and nematicide application

The impact of increasing temperatures on the population dynamics of the soil-dwelling nematode Globodera pallida, a persistent and economically important pest of potatoes, was investigated. The reproductive factor (final population⁄initial population) and length of life cycle were found to be temperature sensitive. Pot experiments performed over 4 months allowed comparison of the effect on development of G. pallida of two temperature regimes: an average temperature comparable to current field conditions (14.3 °C) and an average temperature above current field conditions (17.3 °C). A larger second generation of juveniles was observed at 17.3 °C compared to 14.3 °C. Multiplication of G. pallida at field sites in Shropshire and East Lothian (average soil temperatures of 15.5 and 14.1 °C, respectively, during potato cropping) was also examined. A quantitative PCR assay and visual examination of roots were used to monitor the dynamics of the G. pallida populations in both field sites at 4-weekly intervals. Four cultivars, Desirée, Cara, Maris Piper and Estima, were grown with and without nematicide treatments. Nematicide treatments suppressed population increases at both sites. Females were observed on the roots of cvs Cara and Desirée at the end of the growing season in Shropshire, but not at East Lothian, and are likely to represent a second generation.     

Differential hatching of the potato cyst nematodes Globodera rostochiensis and G. pallida in root diffusates and water of differing ionic composition

The hatching differences ofGlobodera rostochiensis andG. pallida were assessed in potato root diffusate (PRD) of cv. Bintje, cv. Elkana and clone ZB35-29.G. pallida hatched better in the PRDs thanG. rostochiensis. It was shown that the experimental test conditions strongly influenced the hatching results. The water type used in the hatching tests had a significant discriminating effect on the species;G. rostochiensis reached hatch percentages of 60 to 90% in demineralized and tap water, whereasG. pallida never exceeded the 15%. These differences were independent of the various batches that were used or the different years the tests were carried out. Silver sand percolate had a inhibiting effect on the hatching of both nematode species. Boron and a high electrical conductivity may be responsible for this. The results are discussed from an ecological point of view as well as for research consequences.     

The effect of different dosages of aldicarb on the multiplication at small population densities of Globodera rostochiensis on potato in rotavated and non-rotavated plots

The effect of 0.35, 0.5, 0.7, 1, 1.4 and 2 g aldicarb/m², applied at planting time, on the multiplication of small densities ofGlobodera rostochiensis on potato was investigated in an experiment on sandy loam. The chemical was applied broadcast to the soil and rotavated into the top 15 cm on half the plots of each treatment. The plots were ridged three times, the first time immediately after the planting of the potatoes. Nematodes multiplied at the same rate in the top 20 cm of the soil on rotavated and non-rotavated plots treated with the same dosage of the chemical. The relation between log dosage and probit reduction of the multiplication rate in the top 20 cm after the plots had been levelled was linear between 0.35 g and 1.4 g aldicarb/m². The dosage-increase efficiency was 0.3 probit units per doubling of the dosage and the reduction of the multiplication rate at 0.5 g aldicarb/m² 76%, whereas 2 g aldicarb/m² was not more effective than 1.4 g. However, multiplication rates in the centre of the ridges of rotavated plots were reduced by 96.5% at 1 to 2 g aldicarb/m² but only by about 60% below the furrows and by 60% to 80% below the ridges. The latter reduction was the greater the larger the dosage of the chemical.The observations were in accordance with the supposition that multiplication of nematodes was totally inhibited in the top 20 cm of plots treated with 1.4 g and 2 g aldicarb/m² and that postharvest populations there consisted entirely of non-hatched eggs of the pre-plant population. The poor performance of the chemical in the deeper layers of the soil makes application less effective in reducing population build-up than in preventing yield losses.Samenvatting Het effect van 0,35, 0,5, 0,7, 1, 1,4 en 2 g aldicarb/m², toegediend vlak voor het poten, op de vermenigvuldiging vanGlobodera rostochiensis op aardappel werd onderzocht in een veldproef op zavel. Het middel werd breedwerpig over de oppervlakte van de grond verdeeld. Daarna werd de helft van de met elke dosis behandelde en van de onbehandelde veldjes gefreesd tot 15 cm diepte. Er werd drie maal aangeaard. Er was geen verschil in de vermenigvuldiging van de aaltjes in de bovenste 20 cm van de grond tussen wel en van het middel van probit vermindering van het vermenigvuldigingsgetal van het aaltje ten opzichte van onbehandeld in de bovenste 20 cm van de grond was rechtlijnig tussen 0,35 g en 1,4 g aldicarb/m². Het effect van dosisvergroting was 0,3 probit eenheid per verdubbeling van de dosis en de vermindering van het vermenigvuldigingsgetal bij 0,5 g aldicarb/m² 77%. Het effect van 1,4 g en 2 g aldicarb/m² was gelijk. De resultaten zijn in overeenstemming met de veronderstelling, dat in de met 1,4 en 2 g aldicarb/m² behandelde veldjes de vermenigvuldiging van de aaltjes in de bovenste 20 cm van de grond geheel was verhinderd. Met een voor praktische toepassing aanvaardbare dosis aldicarb kon een sterke vermeerdering van aardappelcystenaaltijes beneden 20 cm onder de oppervlakte van de grond niet worden voorkómen. Daardoor is de bruikbaarheid van dit systemische nematicide (en van overeenkomstige middelen) in een bestrijdingssysteem, dat streeft naar het (zeer) laag houden van dichtheden van aardappelcystenaaltjes, problematisch.     

Experimentally evolved populations of the potato cyst nematode Globodera pallida allow the targeting of genomic footprints of selection due to host adaptation

In the current agronomical context of pesticide use reduction, deciphering the genetic bases of pathogen adaptation to plant defences is of major importance to improve durability of resistance. Indeed, knowledge of virulence gene frequencies in pathogen populations could allow the prediction of resistance durability before deployment. Globodera pallida is a major pest of potato crops for which a promising resistance QTL, GpaV_vrn, has been identified in Solanum vernei. An experimental evolution study, in which G. pallida lineages evolved on resistant or susceptible potato genotypes for up to eight generations, previously showed that G. pallida was able to rapidly overcome GpaV_vrn resistance. However, it was not known if enough genetic mixing occurred in these lineages to be able to detect islands of differentiation in a genome scan approach. Here, this question was investigated using 53 polymorphic microsatellite markers distributed along the genome and three different tests based on genetic differentiation and heterozygosity. Eight outlier loci were identified, indicative of genomic regions putatively involved in host adaptation. Several loci were identified by multiple detection methods and/or in two independent adapted lineages. Some candidate genomic regions identified also seemed to be involved in overcoming resistance to nematodes in a plant genotype harbouring the same resistance QTL in a different genetic background. These results validate the feasibility of a genome scan approach on biological material coming from short experimental evolution, and encourage the use of a high coverage genome scan by whole genome resequencing.     

不同茬口条件下的作物根渗出物对大豆胞囊线虫(Heterodera glycines)卵孵化影响

 取北方5种作物轮作茬口和休闲土壤种植火豆、玉米、小麦、亚麻和甜菜,出苗后22 d制备作物的根渗出物,观察其对大豆胞囊线虫卯孵化的影响。试验表明,麦豆麦迎茬的甜菜根渗出物在后期大豆胞囊线虫(SCN)的卵孵化率最高,豆麦米轮作茬的大豆根渗出物9 d后SCN的卵孵化率明显高于其它作物,米豆米茬口的玉米根渗出物SCN的卵孵化率较高,豆麦豆迎茬甜菜根渗出物SCN的卵孵化率明显高于所有供试作物,12年大豆连作茬甜菜从一开始卵孵化率就高于对照和其它4种作物,休闲区的5种作物根渗出物也有对SCN卵孵化的刺激作用。     

马铃薯内生细菌的分离及环腐病拮抗菌的筛选鉴定

 本研究从大同、太原和内蒙古等地采集马铃薯块茎,分离到240株内生细菌,通过离体抑菌作用测定,共得到55株对环腐病菌有拮抗作用的菌株,占菌株总数的22.9%,抑菌圈半径最大的可达13 mm。按抑菌圈半径大小将拮抗菌分为强、中、弱三类。从中筛选出9个对环腐病等病菌具有较强拮抗作用的内生菌株进行了细菌学鉴定,结果表明:118为荧光假单胞生物型V (Pseudomonas fluorescens biovar V);110为短小芽孢杆菌(Bacillus pumilus);085为嗜热脂肪芽孢杆菌(Bacillus stearothermophilus);069为草生欧文氏菌(Erwinia herbicola);043为草莓黄单胞菌(Xanthomonas fragariae);A-10'、T3为芽孢杆菌属(Bacillus);H1-6为荧光假单胞菌(Pseudomonas fluorescens);116为短小杆菌属(Curtobacterium)。     

Suppression of potato cyst nematode root penetration by the endoparasitic nematophagous fungusHirsutella rhossiliensis

The endoparasitic nematophagous fungusHirsutella rhossiliensis was tested for its ability to suppress root penetration and cyst formation by the potato cyst nematode speciesGlobodera pallida. Isolates ofH. rhossiliensis were obtained from infected potato cyst nematode juveniles from different starch potato fields in The Netherlands. The isolates showed no difference in spore adhesion to juveniles on agar plates (adhesion rate: ±90%). The most rapid growing isolate, CBS 108.94, was used for experiments. Vegetative mycelial colonies ofH. rhossiliensis CBS 108.94, grown in potato dextrose broth, were used as soil inoculum. During submerged cultivation the mycelial colonies produced phialides (spore-bearing cells) but no spores. Exposed to the air, however, spores were rapidly formed. The effect of different soil inoculum densities of mycelial colonies on root penetration byGlobodera pallida was examined in an experiment in 250-ml pots. Up to a mycelial colony concentration representing a potential spore density of 10⁴ g^–1 soil no suppression occurred. At approximated densities of 2.5×10⁴ and 10⁵ spores g^–1 soil the numbers of juveniles which penetrated roots were reduced by 30% and 34%, respectively. The distribution of the inoculum could be improved by fragmentation of the mycelial colonies before soil inoculation. Using mycelial fragments, again no suppression of root penetration was observed up to a potential spore density of 10⁴ g^–1 soil, but at densities of 10⁵ and 10⁶ g^–1 a suppression of 54% and 88%, respectively, was measured. In a greenhouse experiment, soil inoculation with mycelial colonies with a potential spore production of 2.5×10⁵ g^–1 soil resulted in a suppression of root penetration of 37% and 51% after 5 and 6 weeks, respectively, but the number of newly formed cysts after 18 weeks in soil was not different for control and inoculated pots. It is concluded thatH. rhossiliensis may be useful for the reduction of root damage caused by juveniles of potato cyst nematodes, but the usefulness for population control is doubtful.