bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction of intrinsic and extrinsic chemical cues in the behaviour of Bursaphelenchus xylophilus (Aphelenchida: Aphelenchoididae) in relation to its beetle vectors
Authors: Linit Marc , Stamps W. Terrell 
Published: January 2003

AbstractBursaphelenchus xylophilus, its host trees and beetle vectors represent an unusual ecological system. The fourth stage, dispersal juvenile (JIV) of B. xylophilus is a specialised life stage that must alter its response to a variety of chemical cues over time to properly enter and exit its beetle vector. Neutral storage (NS) lipid content is proposed as a modifier of nematode response to beetleand tree-produced volatiles. The chemotactic response of JIV to a variety of chemicals was tested and the lipid contents of JIV attracted to particular chemicals were quantified. Nematodes with the lowest NS lipid content were attracted to β-myrcene, a pine volatile, while nematodes with the highest NS lipid content were attracted to toluene, a beetle cuticular hydrocarbon. A rolling fulcrum model of the integration of intrinsic (NS lipid) and extrinsic (volatiles) cues is proposed to explain the behavioural ontogeny of JIV in relation to the beetle vector.
Additional notes on the morphology of Meloidogyne spartinae (Nematoda: Meloidogynidae)
Authors: Hirschmann Hedwig , Eisenback Jonathan 
Published: January 2003

AbstractFemales, males and second-stage juveniles of Meloidogyne spartinae were examined by light and scanning electron microscopy. The morphology of M. spartinae is very typical of the genus for most characters in general. However, as expected, some minor differences occur, particularly in the shape of the head, stylet and tail, and morphometrics of several characters. It is not clear at present how the karyotype of seven chromosomes in M. spartinae is related to the 13-18 chromosomes of other apparently related Meloidogyne species. The M. spartinae karyotype may represent an ancestral form from which the other species have evolved, possibly as polyploid-aneuploids. More studies are needed to clarify this point. However, M. spartinae is remarkably similar in morphology to other species and is justly placed within the genus Meloidogyne.
Descriptions of Prodesmodora zullinii n. sp., P.nigra n. sp. and Chiloplectus loricatus Andrássy, 1985 (Nematoda) from Spanish fir woodlands
Authors: Abolafia Joaquin , Abebe Eyualem , Ocaña Amelia 
Published: January 2003

AbstractThree species of nematodes from the nematofauna found in Spanish fir woodlands (pinsapo forests) are described: Prodesmodora zullinii n. sp., Prodesmodora nigra n. sp. and Chiloplectus loricatus Andrássy, 1985. P. zullinii n. sp. is a relatively small species of this genus, has a variable body length (0.25-0.41 mm), only two denticles on the stoma wall, amphid diam. 25-40% of the corresponding body diam., located at 12.1± 1.2 μm of the anterior end, vulva-anus distance 2-2.3 times the tail length, vaginal wall lightly sclerotised and tail tip pointed. P.nigra n. sp., also a relatively small species (0.53-0.55 mm), is characterised by three denticles on the stoma wall, amphid diam. 30-34% of the corresponding body diam. situated at 17.6 ± 0.9 μm of the anterior end, and vulva-anus distance 2.7-2.9 times the tail length, vaginal sclerotisation wall prominent and tail tip pointed. Two additional differential characters for C. loricatus are the seven to ten rows of denticles of the pharynx valve and two small projections on both sides of the spinneret base. Data are presented on some ecological features of the habitat where these three species were found, as well as taxonomic data comparing the different species of Prodesmodora smaller than 0.55 mm.
Utriculimermis microcaudata n. gen., n. sp., a new genus and species of Mermithidae (Nematoda) of the rivers Lafnitz and Teigitsch in the southeastern Austrian Alps
Authors: Deixelberger Peter , Kaiser Helmut 
Published: January 2003

AbstractUtriculimermis microcaudata n. gen., n. sp. (Nematoda: Mermithidae) is described from the hyporheic biotope of two running waters in southeastern Austria. The mermithids were sampled by pumping and with a modified 'Hess'-sampler. The characteristics of this new genus are: long body length, a very long pharynx which attains about 95% of the body length, six head papillae, mouth opening terminal, six hypodermal chords at midbody level, excretory pore present near the nerve ring, small cupshaped amphids, cuticula lacking cross fibres under light microscope, males with long slightly curved spiculum, very large number of genital papillae, vulva slightly curved to barrel-shaped with vulval flap, postparasitic juveniles with very short tail appendage often only present as a button-like nipple.
Population dynamics of Paratylenchus nanus in soil under pasture: 2. Biotic factors and population modelling
Authors: Watson Richard , Bell Nigel 
Published: January 2003

AbstractSeasonal and monthly sampling of a Paratylenchus nanus population showed that trends in biomass were similar to those for abundance. A Population Age Index (proportional contribution of each life stage multiplied by stage biomass) showed population age increased from a minimum in spring to maximum in winter. From mid-spring to mid-summer, population age was greater in 0-10 than 10-20 cm depth; this may have been due to a greater proportion of juveniles developing over this period at the deeper depth. The populations at 10-20 cm deep included a greater proportion of fourth stage juveniles than those at 0-10 cm. This may reflect the smaller root resource at 10-20 cm depth limiting population development. Monthly sampling of patches of high vs low P.nanus density indicated that such patches retain their densities relative to each other in most months. Evidence is presented for density-dependence in the P. nanus population at 0-10 cm and density-independence at 10-20 cm depth. Multiple regression models were fitted, taking into account all factors (abiotic and biotic) which were significantly associated with P.nanus abundance, and results are discussed to highlight areas still requiring investigation before a complete model of the population dynamics of this nematode can be achieved.
Dynamics of sympatric Paratylenchus nanus and Paratrichodorus minor populations in soil under pasture
Authors: Watson Richard , Bell Nigel 
Published: January 2003

AbstractPopulations of both Paratrichodorus minor and Paratylenchus nanus in a grazed pasture in Waikato, New Zealand were assessed in single 2.5 cm diam. core samples over six successive seasons. Neither seasonal periodicity nor a consistent vertical distribution pattern was observed in the P.minor population. P.nanus had distinct spring and summer population maxima and was more abundant at 0-10 than 10-20 cm depth. P.minor but not P.nanus abundance was significantly correlated with rainfall and an activity index combining rainfall and soil temperature for the week before sampling. Significant correlations among P.minor, P.nanus and concentrations of some soil nutrients seemed to reflect soil nutrient interactions with other biotic factors such as plant growth. There was no evidence for competition between these two nematodes. Host root resource, spatial aggregation and differences in morphology that indicate niche differences are discussed as possible reasons for the observed lack of competition.
Trichodoridae (Nematoda: Triplonchida) in Spain
Authors: Arias María , López-Pérez Antonio , Bello Antonio 
Published: January 2003

AbstractA revision has been made of the Trichodoridae family in Spain. Seventy records were determined or confirmed. Reports of Paratrichodorus cf. acutus (one record) and 24 of Trichodorus species were not confirmed and those of eight species were regarded as erroneous. Thirteen species have been found in Spain, five belonging to the genus Paratrichodorus (P.anemones, P.hispanus, P.minor, P.pachydermus, P.teres) and eight to Trichodorus (T. beirensis, T. cylindricus, T. giennensis, T. lusitanicus, T. primitivus, T. similis, T. sparsus, T. viruliferus). P.minor and P.teres appeared in the Canary Islands. No trichodorids have been reported on the Balearic Islands. T.lusitanicus is a new species for Spain and 33 records are new.
Laboratory culture of two Xiphinema americanum-group species (Nematoda: Longidoridae) from Senegal
Authors: Baujard Pierre , Diop Mamadou , Mounport Danamou , Diémé Jacques-Hubert 
Published: January 2003

AbstractTwo Xiphinema americanum-group species from Senegal were successfully cultured on plants in the laboratory and the effects of host plant, temperature and soil moisture were evaluated. Soil temperature had most effect while soil moisture had no effect on multiplication. Greatest reproduction rates were observed for one species on Pennisetum typhoides (millet) and for the other species on Sorghum vulgare. These two gramineous species were better hosts than the legumes Vigna unguiculata (cowpea) and Arachis hypogaea (peanut). Multiplication was greater when plants were inoculated with freshly extracted nematodes.
Cryopreservation and low temperature storage of the pre-parasitic juveniles of Romanomermis culicivorax
Authors: Platzer Edward , Peng Yufang , Song Jinzhang , Song Yi 
Published: January 2003

AbstractThe effects of low temperature storage and cryopreservation on the survival and infectivity of Romanomermis culicivorax were studied in the laboratory. When pre-parasitic juveniles of R. culicivorax were stored at-2 to 2°C, more than 90% survived for 9 days and 50% were motile for 13 days. The infective ability of the pre-parasitic juveniles for mosquitoes remained high (85%) after 5 days of cold storage and the infectivity was reduced only moderately (50 to 78%) after storage for 6 to 10 days. Various cryoprotectants were investigated to develop a cryopreservation procedure for the infectious pre-parasitic juveniles of R. culicivorax. After suspension in 1, 2.5 or 5% dimethylsulphoxide (DMSO), and cryopreservation with a two-step cooling sequence prior to storage in liquid nitrogen, approximately half of the pre-parasitic juveniles of R. culicivorax, cryopreserved in 2.5 and 5% DMSO, regained motility when thawed quickly after storage for 7 and 125 days. However, revived pre-parasitic juveniles were unable to infect mosquito larvae. Pre-parasitic juveniles treated with ethanediol, hydroxyethyl starch, and polyvinylpyrrolidone as cryoprotectants did not survive the cryopreservation procedure. Similar results were obtained with the pre-parasitic juveniles (PPJ) of Romanomermis yunanensis.
Plant parasitic nematodes associated with plantain (Musa spp., AAB-group) in southern Nigeria and their relative importance compared to other biotic constraints
Authors: Rotimi M. Omolara , De Waele Dirk , Speijer Paul R. 
Published: January 2003

AbstractThe predominant nematode species found on plantain in southern Nigeria was Helicotylenchus multicinctus which occurred at all 68 sites sampled. Hoplolaimus pararobustus, Pratylenchus coffeae and Radopholus similis were found at 64, 50 and 46% of the sites, respectively, while Meloidogyne spp. second stage juveniles were found at 68% of the sites. Other nematode species occurred at less than 5% of the sites and included Helicotylenchus dihystera, P. zeae, P. brachyurus, Rotylenchulus reniformis, Scutellonema and Criconemoides spp. H. multicinctus and P.coffeae occurred at high densities (on average about 10 500 and 3500 nematodes/100 g fresh root weight, respectively), compared to the other species. P.coffeae was more common in the west and mid-west of southern Nigeria, while R. similis was more common in the east. Factors, derived from a principal component analysis of observations of damage caused by nematodes, the banana weevil Cosmopolites sordidus and the fungus Mycosphaerella fijiensis, the cause of Black Sigatoka, were related to plant growth observations. The results suggest that P.coffeae followed by R. similis are the major biotic constraints of plantain production in southern Nigeria. Higher losses are anticipated by these plant parasitic nematodes than by either M. fijienis or C. sordidus.
Plant-parasitic nematodes in field crops in South Africa. 6. Soybean
Authors: McDonald Alexander , Fourie Hendrika , Loots Gideon 
Published: January 2003

AbstractTwelve plant-parasitic nematode genera and 25 species were identified in soil and root samples collected from 17 localities in the soybean production areas of South Africa during the 1995/96 season. Predominant endoparasites found included Meloidogyne incognita, M. javanica, M. hapla, M. ethiopica, Pratylenchus zeae and P. brachyurus. Meloidogyne species occurred in 91% of all root samples, P. zeae in 87% and P. brachyurus in 33%. The occurrence of the three predominant endoparasites was not restricted to sandy soil, but they were also prevalent in soils with high clay contents. Other endoparasitic nematode species were Pratylenchus crenatus, P. teres, P. neglectus, P. thornei, Rotylenchulus parvus and Ditylenchus africanus. Nematodes found in soil included Helicotylenchus dihystera and Scutellonema brachyurus, which occurred in 78 and 71%, respectively, of all soil samples. Other nematodes found in soil samples were Helicotylenchus pseudorobustus, H. digonicus, H. microcephalus, Scutellonema truncatum, Rotylenchus unisexus, Mesocriconema sphaerocephalum, Paratrichodorus minor, Longidorus pisi, Xiphinema vanderlindei, X. elongatum and Tylenchorhynchus goffarti. Highest prominence values (PV) for Meloidogyne species were recorded on cultivars Prima, Bakgat, Tamboti, Hutcheson and Knap and the lowest on cultivars PAN812, SCS1, Nyala, Gazelle and A7119. Eight nematode genera and 19 species extracted during this study are reported for the first time in association with soybean in South Africa.
Presence of the cerambycid beetles Psacothea hilaris and Monochamus alternatus affecting the life cycle strategy of Bursaphelenchus xylophilus
Authors: Maehara Noritoshi , Futai Kazuyoshi 
Published: January 2003

AbstractAlthough fourth-stage dispersal juveniles (JIV) of Bursaphelenchus xylophilus, the pinewood nematode (PWN), developed in the presence of both Monochamus alternatus and Psacothea hilaris, the numbers and the percentage of JIV were far higher in the presence of the former than of the latter. JIV first appeared 7 days after pupation of M. alternatus and the number increased from the day of beetle eclosion to the third day thereafter, then remained stable. We conclude that the presence of specific vectors affects both the life history of the PWN and the numbers of nematodes carried by vectors emerging from killed pine trees.
Invasion, development, growth and egg laying by Meloidogyne javanica in Brassicaceae crops
Authors: Kirkegaard John , McLeod Rod , Steel Christopher 
Published: January 2003

AbstractInvasion, development and egg laying by Meloidogyne javanica in 11 Brassicaceae and four non-Brassicaceae crop species/subspecies was investigated. At 10 to15 and 15 to 20°C, fodder rape cv. Rangi was invaded less than the good hosts tomato cv. Grosse Lisse and field pea cv. Dun but more than the poor host oat cv. Cooba. With an inoculum of 50 second stage juveniles (J2), invasion of Rangi, and the intermediate host subterranean clover cv. Trikkala, were similarly invaded when inoculated with 50 and 100 J2, cv. Rangi was invaded less than tomato. The intermediate host subterranean clover cv. Trikkala and Rangi were similarly invaded when inoculated with 50 and 100 J2 but cv. Trikkala was less invaded with 200 J2. Oat cv. Cooba was always less invaded than the other hosts. Invasion of 3-week-old seedlings of cv. Rangi and 12 cultivars of seven other Brassicaceae crop species/subspecies were similar. Three weeks after inoculation, more M. javanica had developed to the mature female stage in tomato than in the eight Brassicaceae species/subspecies. Females growing in tomato and field pea were always larger than those in rape cv. Rangi. Females in Rangi were larger but those in oilseed radish cv. Adagio were smaller than in 11 other cultivars of seven Brassicaceae, except in plants grown in winter. Egg masses from four Brassicaceae species contained fewer eggs than egg masses from tomato at 6 weeks after inoculation, but at 7 and 8 weeks only those from fodder rape cv. Korina had consistently fewer than tomato. Results are discussed in relation to host status, glucosinolates and potential use of Brassicaceae for control of Meloidogyne.
Life history of Bursaphelenchus conicaudatus (Nematoda: Aphelenchoididae) in relation to the yellow-spotted longicorn beetle, Psacothea hilaris (Coleoptera: Cerambycidae)
Authors: Kanzaki Natsumi , Futai Kazuyoshi 
Published: January 2003

AbstractThe life history of the nematode Bursaphelenchus conicaudatus and its phoretic relationship to the yellow-spotted longicorn beetle, Psacothea hilaris, were studied, and are discussed by comparison with those of the pinewood nematode B. xylophilus, the pathogen of the pine wilt disease, and its vectors Monochamus species. The life history of B. conicaudatus was found to be very similar to that of B. xylophilus in dispersal pattern, vector selection and feeding preference, although the average number of B. conicaudatus carried by the yellow-spotted longicorn beetle, the proportion of beetles infested with the nematodes, and the nematode release pattern differed from those of B. xylophilus. These findings indicate a close relationship between the two species of Bursaphelenchus and the cerambycid beetles, as well as the adaptability of these two nematode species to the life cycles of their vectors.
Present status and future of nematode systematics
Authors: Coomans August 
Published: January 2003

AbstractSince phylogenetic systematics became generally accepted and especially since informatics and molecular techniques for phylogenetic analysis were developed, systematics has undergone a conceptual and methodological revolution. Taxonomy, on the contrary, suffered a decline. Poor descriptions, too much routine work and low citation rates hampered it. As a result, the discipline became less attractive to young scientists. With only a small fraction of the biodiversity known, this situation will lead to serious problems in the future in all those fields of nematology depending on a correct identification of species. Phylogenetic analyses of nematodes have been mainly based on morphology, supplemented with developmental characters, but in recent years molecular methods have provided entirely new data sets. Phylogenetic estimates derived from independent data may provide new insights in character homologies through reciprocal illumination. Classifications of nematodes were often biased according to the expertise of the author and were only recently based on the principles of phylogenetic systematics. Recently, molecular and morphological data have been used to support a new overall classification with only (presumably) monophyletic taxa. In this classification plant, as well as animal, parasitic taxa are hierarchically downgraded in accordance with their phylogenetic history. Species occupy an important position in all aspects of biology, therefore the species concept matters. It determines, for example, the outcome of biodiversity assessments, distribution patterns, etc. However, several problems remain to be solved before a consensus will be reached about the choice of a concept. Future research in nematode systematics should comprise well-focused taxonomy based on a combination of classical and modern methods in a way that can raise the interest of young scientists as well as of funding agencies. It should be realised that, with the dwindling present taxonomic expertise, this is a very urgent matter.
Meloidogyne brasilensis n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitising tomato cv. Rossol in Brazil
Authors: Eisenback Jonathan , Charchar João 
Published: January 2003

AbstractMeloidogyne brasilensis n. sp., Londrina and Brasilia populations, is described and illustrated from specimens from tomato cv. Rossol and pea cv. Mikado, respectively, in Brazil. Characteristically, the perineal pattern is elongated to ovoid with a flattened to very high, squarish dorsal arch with widely spaced, coarse striae. The lateral fields may have wing-like striae on one or both sides. The female stylet is 14 μm long with narrow and elongated knobs that are distinctly set-off from the shaft. The excretory pore is variable in location, but generally opens near the anterior portion of the median bulb about 50 μm from the head end. The male is 1.89 mm long and has a high head cap that slopes posteriorly. The labial disc is separated from the medial lips by a deep, rounded groove. The delicate stylet of the male is 23 μm long and has small, rounded knobs that are distinctly set-off from the shaft which has numerous small, rounded projections. Mean second-stage juvenile length is 434 μm. The juvenile head cap is highly elevated, the medial lips are crescent-shaped and unequal in size, and the head region is not annulated. The stylet is 11 μm long and has small, rounded, posteriorly sloping knobs. The tail is 53 μm long; it is marked with large, irregular annules and ends in a bluntly rounded tip. The hyaline tail terminus is short (13 μm). Reproduction occurred on NC95 tobacco, tomato, pea, and bean, whereas pepper, watermelon, peanut, cotton, corn, and soybean were not hosts.
Free-living nematodes from nature reserves in Costa Rica. 2. Mononchina
Authors: Bongers Tom , Zullini Aldo , Loof Pieter 
Published: January 2003

AbstractIn soil, moss and freshwater habitats of tropical forests in Costa Rica, 20 mononch species were found. Two are described as new species. Mononchus laminatus n. sp. (L = 1.5-1.9 mm, buccal capsule 29-31 × 11-14 μm, c′ = 3.6-4.9, similar to M. aquaticus but with a subventral lamina present in anterior part of buccal cavity, and amphid aperture posterior to the dorsal tooth) and Miconchus gomezi n. sp. (similar to M. digiturus, but with slender body, vulva cuticularised and with a reduced posterior genital branch). The known species are redescribed, the well-known ones briefly, the less known more extensively. Brazilian and Costa Rican specimens of Paracrassibucca paucidentata Lordello, 1970 were studied and a lectotype has been designated. The other species found are: Mononchus truncatus Bastian, 1865; M. aquaticus Coetzee, 1968; M. tunbridgensis Bastian, 1865; Coomansus parvus (de Man, 1880); Coomansus sp. (C. zschokkei-group); Prionchulus muscorum (Dujardin, 1845); P.punctatus Cobb, 1917; Cobbonchus coetzeeae Andrássy, 1970; Mylonchulus contractus Jairajpuri, 1970; M. hawaiiensis (Cassidy, 1931); M. obtusicaudatus (von Daday, 1899); M. parabrachyuris (Thorne, 1924); M. sigmaturus Cobb, 1917; Mulveyellus monhystera (Cobb, 1917); Iotonchus tenuidentatus (Kreis, 1924); I. trichurus Cobb, 1917 and Miconchus digiturus (Cobb, 1893).
A PCR primer set for determination of phylogenetic relationships of Bursaphelenchus species within the xylophilus group
Authors: Kanzaki Natsumi , Futai Kazuyoshi 
Published: January 2003

AbstractThe phylogenetic relationships of Bursaphelenchus conicaudatus with B. abruptus, B. fraudulentus, B. mucronatus and B. xylophilus species were analysed based on the DNA base sequences of 18S, 5.8S, ITS1 and ITS2 of rDNA and the partial code of mitochondrial cytochrome oxidase subunit I (COI) gene. The monophyly of B. abruptus and the other species in the xylophilus group was not supported, and B. abruptus could be excluded from the xylophilus group. The other species, i.e ., B. conicaudatus, B. fraudulentus, B. mucronatus and B. xylophilus were assumed to be monophyletic. The ancestor of these four species is assumed to have originated in the eastern part of the Eurasian continent as a free-living nematode inhabiting broad-leaved trees. First, B. conicaudatus branched from the ancestor in eastern Asia. Then B. fraudulentus and B. mucronatus separated from the ancestor. B. mucronatus changed its host from broad-leaved trees to conifers and spread throughout the coniferous forest over the Eurasian continent and North America. B. xylophilus might originate from a population of B. mucronatus remaining in North America after B. mucronatus had diversified.