SEM and TEM studies have been undertaken to unravel the cuticle structure of Criconema paradoxiger (Orton Williams, 1982) Raski & Luc, 1985 and to demonstrate the taxonomic status of this species. The peculiar structure of the lip region and the taxonomic value generally assigned to this character within the Criconematidae are arguments to consider Amphisbaenema as a separate genus, restricting it to the type species.
{"title":"Criconema Paradoxiger (Orton Williams, 1982) Raski & Luc, 1985: Cuticle Ultrastructure and Revalidation of the Genus Amphisbaenema","authors":"W. Decraemer, J. Baldwin, C. Eddleman, E. Geraert","doi":"10.1163/004525996X00028","DOIUrl":"https://doi.org/10.1163/004525996X00028","url":null,"abstract":"SEM and TEM studies have been undertaken to unravel the cuticle structure of Criconema paradoxiger (Orton Williams, 1982) Raski & Luc, 1985 and to demonstrate the taxonomic status of this species. The peculiar structure of the lip region and the taxonomic value generally assigned to this character within the Criconematidae are arguments to consider Amphisbaenema as a separate genus, restricting it to the type species.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88293214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Five species belonging to the genus Filenchus, including a new species and one species of Coslenchus were found in soil samples collected from natural grassland in Argentina. Other samples were collected from a fallow field previously cultivated with potatoes. Scanning electron micrographs are presented for F. dittisimus, F. facultativus, F. baloghi, F. balcarceanus sp. n. and Coslenchus rhombus. Filenchus balcarceanus sp. n. is distinguished by its lateral field with two lincs setting off a single band which bears 2-4 irregular lines seen only by SEM, the variable head shape and annulation. The five species are first records from Argentina.
{"title":"Tylenchidae from Buenos Aires, Argentina.","authors":"M. Torres, E. Geraert","doi":"10.1163/187529296X00058","DOIUrl":"https://doi.org/10.1163/187529296X00058","url":null,"abstract":"Five species belonging to the genus Filenchus, including a new species and one species of Coslenchus were found in soil samples collected from natural grassland in Argentina. Other samples were collected from a fallow field previously cultivated with potatoes. Scanning electron micrographs are presented for F. dittisimus, F. facultativus, F. baloghi, F. balcarceanus sp. n. and Coslenchus rhombus. Filenchus balcarceanus sp. n. is distinguished by its lateral field with two lincs setting off a single band which bears 2-4 irregular lines seen only by SEM, the variable head shape and annulation. The five species are first records from Argentina.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85363838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
General aspects of the morphology and taxonomy of the genus Tylencholaimus de Man, 1876 are described and discussed. The variability and taxonomic importance of several morphological features are evaluated. Intrageneric relationships are also analyzed but no division is proposed due to the impossibility of distinguishing clear natural groups; a list of the species included in the genus and a key to their identification are given. Relationships with other close genera are briefly discussed; Pseudotylencholaimus (Jairajpuri & Ahmad, 1992) n. grad. is proposed and P. viduus (Jairajpuri, 1965) Jairajpuri & Ahmad, 1992 is described and illustrated.
{"title":"Revision of the Genus Tylencholaimus De Man, 1876. General Discussion and Key To the Species","authors":"R. P. Santiago, A. Coomans","doi":"10.1163/004525996X00046","DOIUrl":"https://doi.org/10.1163/004525996X00046","url":null,"abstract":"General aspects of the morphology and taxonomy of the genus Tylencholaimus de Man, 1876 are described and discussed. The variability and taxonomic importance of several morphological features are evaluated. Intrageneric relationships are also analyzed but no division is proposed due to the impossibility of distinguishing clear natural groups; a list of the species included in the genus and a key to their identification are given. Relationships with other close genera are briefly discussed; Pseudotylencholaimus (Jairajpuri & Ahmad, 1992) n. grad. is proposed and P. viduus (Jairajpuri, 1965) Jairajpuri & Ahmad, 1992 is described and illustrated.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75654042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In a 40-week pot experiment, population development and reproduction of Pratylenchus bolivianus on Alstroemeria cv. Jubilee were investigated. Thirty-two weeks after planting in soil initially infested with 24 P. bolivianus/ 100 cm 3 soil, nematode populations in subterranean plant parts and soil reached maxima of 3,350/10 g and 266/ 100 cm 3 , respectively, giving an overall reproduction factor of x59. In a 2-year pot experiment, population development, reproduction and crop damage were investigated in relation to four initial inoculum levels (Pi): 0, 24, 1 19 and 468 nematodcs/ 100 cm 3 soil. After two years the lateral roots of the infested treatments contained about 20,000 P. bolivianus/10 g and the soils of Pi=24, 119 and 468 were infested with 299, 485 and 1,284 P. bolivianus/ 100 cm 3 and resulted in reproduction factors of ×97.1, ×23.8 and ×3.4, respectively. All infested treatments affected root growth and flower production, with reductions in root weight, number of flowers, weight/flower, length of flower stem and weight/cm of flower stem ranging from 18-75%, 8-17%, 16-22%, 10-13% and 10-17%, respectively. The greatest reductions were found in the treatment with the highest Pi. Although P. bolivianus caused modcrate yield losses, the damage threshold density is less than 24 P. bolivianus/100 cm 3 soil at planting. No specific leaf symptoms were noticed, but lesions on subterrancan stem parts were related to infection with P. bolivianus.
通过盆栽试验，研究了玻利维亚小叶蝉在桤木上的种群发育和繁殖情况。朱比利被调查了。种植32周后，地下植物部分和土壤线虫种群数量分别达到最大值3350 /10 g和266/ 100 cm 3，总体繁殖系数为x59。在2年盆栽试验中，研究了线虫种群发展、繁殖和作物危害与4个初始接种水平(Pi)的关系:0、24、1 19和468只线虫/ 100 cm 3土壤。2年后，侵染处理侧根侵染量约为20000只/10 g, Pi=24、119和468土壤侵染量为299只、485只和1284只/ 100 cm 3，繁殖因子分别为×97.1、×23.8和×3.4。所有侵染处理均影响了根的生长和花的产量，根重、花数、花重/花、花柄长和花柄重/厘米的降幅分别为18-75%、8-17%、16-22%、10-13%和10-17%。在Pi最高的处理中发现最大的降低。虽然造成了中度产量损失，但种植时的危害阈值密度小于24只/100 cm 3土壤。没有发现特定的叶片症状，但地下茎部的病变与玻利维亚葡萄球菌感染有关。
{"title":"Population dynamics and damage potential of the root-lesion nematode, Pratylenchus bolivianus, on Alstroemeria","authors":"J. Amsing","doi":"10.1163/187529296X00076","DOIUrl":"https://doi.org/10.1163/187529296X00076","url":null,"abstract":"In a 40-week pot experiment, population development and reproduction of Pratylenchus bolivianus on Alstroemeria cv. Jubilee were investigated. Thirty-two weeks after planting in soil initially infested with 24 P. bolivianus/ 100 cm 3 soil, nematode populations in subterranean plant parts and soil reached maxima of 3,350/10 g and 266/ 100 cm 3 , respectively, giving an overall reproduction factor of x59. In a 2-year pot experiment, population development, reproduction and crop damage were investigated in relation to four initial inoculum levels (Pi): 0, 24, 1 19 and 468 nematodcs/ 100 cm 3 soil. After two years the lateral roots of the infested treatments contained about 20,000 P. bolivianus/10 g and the soils of Pi=24, 119 and 468 were infested with 299, 485 and 1,284 P. bolivianus/ 100 cm 3 and resulted in reproduction factors of ×97.1, ×23.8 and ×3.4, respectively. All infested treatments affected root growth and flower production, with reductions in root weight, number of flowers, weight/flower, length of flower stem and weight/cm of flower stem ranging from 18-75%, 8-17%, 16-22%, 10-13% and 10-17%, respectively. The greatest reductions were found in the treatment with the highest Pi. Although P. bolivianus caused modcrate yield losses, the damage threshold density is less than 24 P. bolivianus/100 cm 3 soil at planting. No specific leaf symptoms were noticed, but lesions on subterrancan stem parts were related to infection with P. bolivianus.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73518993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To enhance the control of sedentary, subterranean insect pest species like Otiorhynchus sulcatus, 19 new alpine isolates of entomopathogenic nematodes were screened for infectivity at 9°C. For this purpose, nematode dispersal was studied in the presence of late instar Galleria mellonella and O. sulcatus, using a T-tube choice system filled with moist sand. For each isolate five characteristics were recorded: migration rate, average distance travelled, host-finding ability, parasitisation rate, and invasion rate. As expected, most isolates accumulated in the host compartments. The rank sum of the isolates, calculated according to the ranks attained for each of the five characteristics, classified seven Steinernema kraussei before the first S. feltiae. However, no single isolate was clearly the most infective. Steinernema sp. 1, Heterorhabditis CH-H-FLU91, and the commercially available S. feltiae OBS III yielded lowest scores. They are considered unsuitable control agents at low temperatures. The locomotory activity of the nematodes in dispersal assays with G. mellonella was significantly correlated with their efficacy at 8.5± 1°C against O. sulcatus in pot experiments. This indicates that T-tube choice experiments as performed in this study represent a meaningful tool for selecting cold-active nematodes. In supplementary dispersal experiments with larvae of Melolontha melolontha, biological control-performance of the four nematode species tested was meagre.
{"title":"Dispersal and host-finding ability of entomopathogenic nematodes at low temperatures","authors":"W. Steiner","doi":"10.1163/004325996X00084","DOIUrl":"https://doi.org/10.1163/004325996X00084","url":null,"abstract":"To enhance the control of sedentary, subterranean insect pest species like Otiorhynchus sulcatus, 19 new alpine isolates of entomopathogenic nematodes were screened for infectivity at 9°C. For this purpose, nematode dispersal was studied in the presence of late instar Galleria mellonella and O. sulcatus, using a T-tube choice system filled with moist sand. For each isolate five characteristics were recorded: migration rate, average distance travelled, host-finding ability, parasitisation rate, and invasion rate. As expected, most isolates accumulated in the host compartments. The rank sum of the isolates, calculated according to the ranks attained for each of the five characteristics, classified seven Steinernema kraussei before the first S. feltiae. However, no single isolate was clearly the most infective. Steinernema sp. 1, Heterorhabditis CH-H-FLU91, and the commercially available S. feltiae OBS III yielded lowest scores. They are considered unsuitable control agents at low temperatures. The locomotory activity of the nematodes in dispersal assays with G. mellonella was significantly correlated with their efficacy at 8.5± 1°C against O. sulcatus in pot experiments. This indicates that T-tube choice experiments as performed in this study represent a meaningful tool for selecting cold-active nematodes. In supplementary dispersal experiments with larvae of Melolontha melolontha, biological control-performance of the four nematode species tested was meagre.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88462587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Genhui Chen, P. Maxwell, G. B. Dunyhy, J. M. Webster
{"title":"Culture conditions for Xenorhabdus and Photorhabdus symbionts of entomopathogenic nematodes","authors":"Genhui Chen, P. Maxwell, G. B. Dunyhy, J. M. Webster","doi":"10.1163/187529296X00139","DOIUrl":"https://doi.org/10.1163/187529296X00139","url":null,"abstract":"","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90483542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three new species of Hemicycliophora are described and illustrated. Hemicycliophora altapadii sp.n. is characterized by its relatively large body size; conoid lip region with three annules, indented dorsovcntrally; a rectangular oral disc; elongated vulval lips; absence of longitudinal lines and R>370. H. meghalayaensis sp.n. also has a relatively large body; low flat lip region with three annules, first lip annule dorsoventrally indented; oral disc rectangular with central oval part surrounded by narrow collar; elongated vulval lips; absence of longitudinal lines and R=295-340. H. postamphidia sp.n. has a moderately large body; a conoid lip region with three lip annulcs, amphidial apertures covered by lateral shields and located away from oral disc; vulval lips three annules long; tail elongate conoid, then spicate with finely rounded terminus, R=340-372.
{"title":"Three New Species of Hemicycliophora De Man, 1921 From India","authors":"P. F. Rahaman, I. Ahmad, M. S. Jairajpuri","doi":"10.1163/187529296X00030","DOIUrl":"https://doi.org/10.1163/187529296X00030","url":null,"abstract":"Three new species of Hemicycliophora are described and illustrated. Hemicycliophora altapadii sp.n. is characterized by its relatively large body size; conoid lip region with three annules, indented dorsovcntrally; a rectangular oral disc; elongated vulval lips; absence of longitudinal lines and R>370. H. meghalayaensis sp.n. also has a relatively large body; low flat lip region with three annules, first lip annule dorsoventrally indented; oral disc rectangular with central oval part surrounded by narrow collar; elongated vulval lips; absence of longitudinal lines and R=295-340. H. postamphidia sp.n. has a moderately large body; a conoid lip region with three lip annulcs, amphidial apertures covered by lateral shields and located away from oral disc; vulval lips three annules long; tail elongate conoid, then spicate with finely rounded terminus, R=340-372.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86563685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amphimictic populations of lesion nematodes with two lip annuli were detected from pasture grasses, Paspalum notatum and Panicum hemitomon, in central Florida. When cultured on carrot disks, these Pratylenchus species differed (P = 0.05) from P. coffeae cultures with respect to posterior uterine sac length (28 and 34.5 μm vs 53.5 μm), vulva % (77.5 and 77.4 vs 79.7), b (5.4 and 6.01 vs 6.4) and c (17 and 17.3 vs 21.3) ratios and shape of tail (narrowly rounded vs bluntly rounded, truncate or indented). Morphometric differences between these lesion nematode populations and P. coffeae tended to be greater when collected directly from their original hosts (grasses and citrus) than from carrot cultures. Morphological characters of Pratylenchus species from grasses were similar to those of P. loosi. The lesion nematodes from grasses, however, had females with more anterior vulva (76-79) than P. loosi paratypes (79-85) from Sri Lanka.
在美国佛罗里达州中部的牧草雀稗(Paspalum notatum)和半芒雀稗(Panicum hemitomon)中检测到2个唇环的病变线虫两性居群。当在胡萝卜圆盘上培养时，这些Pratylenchus物种在子宫后囊长度(28和34.5 μm vs 53.5 μm)，外阴%(77.5和77.4 vs 79.7)， b(5.4和6.01 vs 6.4)和c(17和17.3 vs 21.3)比率以及尾巴形状(窄圆vs直圆，截形或凹形)方面与咖啡P (P = 0.05)不同。这些病变线虫种群与咖啡线虫之间的形态差异往往在直接从其原始寄主(草和柑橘)收集时比从胡萝卜培养物收集时更大。禾草中Pratylenchus种的形态特征与松茸相似。然而，来自禾草的病变线虫的雌性前外阴(76-79)多于来自斯里兰卡的松散线虫副型(79-85)。
{"title":"Pratylenchus loosi from pasture grasses in central Florida","authors":"R. Inserra, L. Duncan, N. Vovlas, P. Loof","doi":"10.1163/004325996X00020","DOIUrl":"https://doi.org/10.1163/004325996X00020","url":null,"abstract":"Amphimictic populations of lesion nematodes with two lip annuli were detected from pasture grasses, Paspalum notatum and Panicum hemitomon, in central Florida. When cultured on carrot disks, these Pratylenchus species differed (P = 0.05) from P. coffeae cultures with respect to posterior uterine sac length (28 and 34.5 μm vs 53.5 μm), vulva % (77.5 and 77.4 vs 79.7), b (5.4 and 6.01 vs 6.4) and c (17 and 17.3 vs 21.3) ratios and shape of tail (narrowly rounded vs bluntly rounded, truncate or indented). Morphometric differences between these lesion nematode populations and P. coffeae tended to be greater when collected directly from their original hosts (grasses and citrus) than from carrot cultures. Morphological characters of Pratylenchus species from grasses were similar to those of P. loosi. The lesion nematodes from grasses, however, had females with more anterior vulva (76-79) than P. loosi paratypes (79-85) from Sri Lanka.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76426905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Six free-living marine nematode species (Diplolaimella ocellata, Diplolaimelloides deconincki, Geomonhystera disjuncta, Daptonema riemanni, Sabatieria pulchra and Enoplus communis) have been isolated from different localities and microhabitats. They all make sinusoidal burrows when moving in agar. In laboratory experiments, at normal and low (ca. 5% atm. sat.) oxygen tensions, bacteria and the ciliate Uronema subsequently colonized the burrows. The addition of nematodes to a patch of agar with bacteria stimulated bacterial growth and burrows made by nematodes expanded the available space for a microbial colonization in an otherwise sterile agar. The observations are discussed in relation to bioturbative effects caused by interstitial nematodes affecting pore water chemistry and decomposition of organic matter in the sea bed.
{"title":"Burrows of Marine Nematodes as Centres for Microbial Growth","authors":"P. Jensen","doi":"10.1163/004425996X00056","DOIUrl":"https://doi.org/10.1163/004425996X00056","url":null,"abstract":"Six free-living marine nematode species (Diplolaimella ocellata, Diplolaimelloides deconincki, Geomonhystera disjuncta, Daptonema riemanni, Sabatieria pulchra and Enoplus communis) have been isolated from different localities and microhabitats. They all make sinusoidal burrows when moving in agar. In laboratory experiments, at normal and low (ca. 5% atm. sat.) oxygen tensions, bacteria and the ciliate Uronema subsequently colonized the burrows. The addition of nematodes to a patch of agar with bacteria stimulated bacterial growth and burrows made by nematodes expanded the available space for a microbial colonization in an otherwise sterile agar. The observations are discussed in relation to bioturbative effects caused by interstitial nematodes affecting pore water chemistry and decomposition of organic matter in the sea bed.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73626926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The virulence spectrum of the potato cyst nematodes (PCN), Globodera pallida and G. rostochiensis, from the Island of Tenerife was assessed and compared with that found in Europe. Within the G. rostochiensis populations, all the Canarian populations, with the exception of one (R2), were avirulent to the H1 resistance gene and therefore belong to the virulence group Ro1/Ro4. Within the G. pallida populations from Tenerife it was apparent that the virulence gene which overcomes the H2 resistance gene is present only at a low frequency. Four populations, P4, P7, P8 and P13, would be classified as pathotype Pa1. A wide range of variation in virulence against clones derived from S. vernei was observed, indicating a continuum of virulence, rather than discrete pathotypes. There was some correlation between the fitness of the populations on the hosts derived from S. vernei and those with no resistance, but less correlation between virulence on the ex-S. vernei clones and one derived from ex-S. tuberosum ssp. andigena CPC 2802. The reproduction of the G. pallida populations on three ex-S. vernei clones also indicated that increasing resistance is predominantly additive and that the nature of virulence towards the three ex-S. vernei clones tested is similar. The differences in the multiplication of the populations on a particular clone may reflect the number of resistance genes present in the clone. A clone derived from ex-S. tuberosum ssp. andigena CPC 2802 was comparatively uniformly resistant to all the populations. Its resistance appears to be different from that in the ex-S. vernei clones and to interact with at least in part, different genes in G. pallida for virulence. The nature of resistance in the different clones tested and aspects concerning the epidemiology of potato cyst nematodes are discussed.
{"title":"Virulence of Canarian Populations of Potato Cyst Nematodes (Globodera Spp.)","authors":"J. A. González, M. Phillips, D. Trudgill","doi":"10.1163/004325996X00048","DOIUrl":"https://doi.org/10.1163/004325996X00048","url":null,"abstract":"The virulence spectrum of the potato cyst nematodes (PCN), Globodera pallida and G. rostochiensis, from the Island of Tenerife was assessed and compared with that found in Europe. Within the G. rostochiensis populations, all the Canarian populations, with the exception of one (R2), were avirulent to the H1 resistance gene and therefore belong to the virulence group Ro1/Ro4. Within the G. pallida populations from Tenerife it was apparent that the virulence gene which overcomes the H2 resistance gene is present only at a low frequency. Four populations, P4, P7, P8 and P13, would be classified as pathotype Pa1. A wide range of variation in virulence against clones derived from S. vernei was observed, indicating a continuum of virulence, rather than discrete pathotypes. There was some correlation between the fitness of the populations on the hosts derived from S. vernei and those with no resistance, but less correlation between virulence on the ex-S. vernei clones and one derived from ex-S. tuberosum ssp. andigena CPC 2802. The reproduction of the G. pallida populations on three ex-S. vernei clones also indicated that increasing resistance is predominantly additive and that the nature of virulence towards the three ex-S. vernei clones tested is similar. The differences in the multiplication of the populations on a particular clone may reflect the number of resistance genes present in the clone. A clone derived from ex-S. tuberosum ssp. andigena CPC 2802 was comparatively uniformly resistant to all the populations. Its resistance appears to be different from that in the ex-S. vernei clones and to interact with at least in part, different genes in G. pallida for virulence. The nature of resistance in the different clones tested and aspects concerning the epidemiology of potato cyst nematodes are discussed.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77607445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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