Showing papers in "Nematologica in 1969"
TL;DR: The distribution of Meloidogyne spp.
Abstract: The distribution of Meloidogyne spp. in tropical Africa is influenced by host plants and by locality. In East Africa M. javanica and M. incognita are the commonest species on food plants; M. hapla commonly attacks pyrethrum; several other species are found in coffee roots.
60 citations
TL;DR: Cultures of Mononchoides potohikus have been maintained on agar plates with a bacterium and the predation rate of the apparently non-functional males is significantly greater than that of females.
Abstract: Cultures of Mononchoides potohikus have been maintained on agar plates with a bacterium (Bacillus cereus var. mycoides). Also M. potohikus has been found to be a facultative predator, preying on a wide range of nematode species. The predation rate of females is independent of the prey species, the presence of old tracks of the prey species, and the presence of a bacterial film. Predation rate is not affected by satiation but is dependent on prey density and is affected by the presence of water on the agar plate. The predation rate of the apparently non-functional males is significantly greater than that of females.
45 citations
TL;DR: Heterodera latipons n.
Abstract: Heterodera latipons n. sp., which was found on the roots of wheat and barley in Israel and Tripoli, can also infest oats and rye. The cysts resemble those of H. turcomanica Kirjanova & Shagalina, 1965, but lack the gland-like structures on the cyst wall and the eggs are larger, 112 X 48 μ, instead of 77 × 40 μ. Eggs and larvae are smaller than those of H. avenae and the fenestration of the cyst cone is different.
42 citations
TL;DR: Dorylaimoidea comprising 65 valid genera is re-classified and Six new families and six new sub-families are proposed and five sub- families are upgraded.
Abstract: Crateronematidae n. fam. is proposed for the new genus Crateronema which is characterized by having a wide stoma and sclerotized anterior part of pharynx. Poronemella n. gen. is proposed for P, porifer (Loof, 1964) and P. amini n. sp. and is close to Lordelloyzema. Chrysonemoides n. gen. differs from Chrysonema in the arrangement of the labial papillae and the two genera constitute the new family Chrysonematidae. Dorylaimoidea comprising 65 valid genera is re-classified. Six new families and six new sub-families are proposed and five sub-families are upgraded.
40 citations
TL;DR: X. mediterraneum, the smallest species identified, was predominant in clayey and poorly aerated soils; most other species prevailed in lighter soils, their relative population sizes increasing in these soils in an almost direct relationship to their volumes.
Abstract: Ten species of Xiphinema (X. brevicolle, X. diversicaudatum, X. elongatum, X. index, X. ingens, X. insigne, X. italiae, X. mediterraneum, X. pini and X. turcicum) and six species of Longidorus (L. africanus, L. brevicaudatus, L. laevicapitatus, L. taniwha, L. vineacola and Longidorus sp.), their regional distribution, nature habitats and relative frequency of occurrence in cultivated fields, are reported from Israel. Males of X. brevicolle and X. insigne, hitherto unknown, are described and additional data on the male of X. mediterraneum are presented. Vertical distribution studies on seven species of Xiphinema and two species of Longidorus revealed maximum population levels of all species in the 0-30 cm layer, with a decrease in numbers with increasing depth. Proportions of adult females in relation to larval stages, studied on three ubiquitous species of Xiphinema, were found to increase with increasing depth. No consistent or characteristic pattern in seasonal fluctuations could be discerned in total field populations of any of the species studied; however, a peak in the proportion of adults was observed in most species during the summer months of May-July. A constant relationship was found between the occurrence of the ubiquitous and apparently polyphagous nematode species and soil type. X. mediterraneum, the smallest species identified, was predominant in clayey and poorly aerated soils; most other species prevailed in lighter soils, their relative population sizes increasing in these soils in an almost direct relationship to their volumes.
38 citations
TL;DR: Aseptic Beta vulgaris root explants were penetrated by 35-45 percent of axenized Heterodera ichachtii larvae added to agar culture media.
Abstract: Aseptic Beta vulgaris root explants were penetrated by 35-45 percent of axenized Heterodera ichachtii larvae added to agar culture media. Maximum penetration occurred at 25°C within 5 days of inoculation. Higher levels of inoculum did not increase percentage penetration. Concentration of constituents in the medium influenced penetration. When concentrations of vitamin stock and sucrose were increased percentage penetration increased. This response did not occur with the macronutrient salts stock. Monoxenic excised roots of the three Beta species B. patellaris, B. procumbens and B. webbiana demonstrated different degrees of resistance to penetration.
34 citations
TL;DR: Hand-picked nematodes of five species of Xiphinema and one species of Longidorus were reared in laboratory cultures for 9 months on young seedlings of some woody and herbaceous plant varieties to find the minimum time required for completion of the life cycle on a suitable host at a permanent temperature range of 20-23°C.
Abstract: Hand-picked nematodes of five species of Xiphinema and one species of Longidorus were reared in laboratory cultures for 9 months on young seedlings of some woody and herbaceous plant varieties. X. index completed its life cycle on sour orange (Citrus aurantium), grapevine (Vitis vinifera) and dwarf nettle (Urtica urens), and multiplied on strawberry (Fragaria X ananassa) and bur marigold (Bidens tripartita). X. brevicolle completed its life cycle on sour orange, grapevine and dwarf nettle, and multiplied on strawberry. L. africanus completed its life cycle on bur marigold and grapevine, and failed to multiply on any of the other plants tested. X. italiae and X. diversicaudatum multiplied slightly on sour orange and grapevine, while X. mediterraneum failed to multiply on any of the plants tested. The minimum time required for completion of the life cycle on a suitable host at a permanent temperature range of 20-23°C was found to be between 7 and 9 months for X. index, between 4 and 7 months for X. brevicolle and less than 4 months for L. africanus.
34 citations
TL;DR: An analysis of previously published and fresh data emphasises the possible significance of movement patterns in orientation and in sampling the environment by nematodes and comparison is made of the asymmetry of lateral undulation in several Nematodes.
Abstract: An analysis of previously published and fresh data emphasises the possible significance of movement patterns in orientation and in sampling the environment by nematodes. A comparison is made of the asymmetry of lateral undulation in several nematodes and examples are given from P. redivivus which suggest that such asymmetries may be influenced by temperature and electrical currents. Vertical and horizontal movement patterns in P. redivivus are also related to orientation mechanisms.
31 citations
TL;DR: Measurements of the wave characteristics of M. javanica on different concentrations of agar suggest that the nematode increases its muscular effort to overcome increased resistance to locomotion while conserving its energy reserves for infectivity and maintaining an efficient means of orienting to exudates released by the host plant root.
Abstract: Measurements of the wave characteristics of M. javanica on different concentrations of agar suggest that the nematode increases its muscular effort to overcome increased resistance to locomotion while conserving its energy reserves for infectivity and maintaining an efficient means of orienting to exudates released by the host plant root.
30 citations
TL;DR: A new order, Mononchida is proposed to contain the Bathyodontoidea (Clark, 1961) n.
Abstract: This is the first paper of the series on mononchs of India; it takes into account species of Hadronchus, Iotonchus, and Miconchus and it also deals with a revised classification of the group. Hadronchus andamanicus n. sp., has an apex of its dorsal tooth in posterior half of buccal cavity, mono-prodelphic gonad with a large posterior uterine sac, vulval papillae, caudal glands with terminal opening and a long filiform tail 6-10 anal body-widths long. Hadronchus shakili n. sp., is quite similar to H. andamanicus but has two ovaries. Iotonchus baqrii n. sp., is mono-prodelphic and unique in having large cuticularized pieces in the vagina at 9-12 μ from vulva. Iotonchus indicus n. sp., has two ovaries, basal dorsal-tooth, elongate-conoid tail 6-9 anal body-widths long and a subterminal opening to caudal glands. Miconchus dalhousiensis n. sp., has two ovaries, three equal sized basal teeth and tail about 4 anal body-widths long without caudal glands. Two known species, Iotonchus trichurus and Miconchus digiturus have also been recorded. A new order, Mononchida is proposed to contain the Bathyodontoidea (Clark, 1961) n. rank. and Mononchoidea (Chitwood, 1937) Clark, 1961. The superfamily Bathyodontoidea includes two families: Bathyodontidae Clark, 1961 and Mononchulidae (De Coninck, 1965) n. rank. The superfamily Mononchoidea includes the family Mononchidae Chitwood, 1937 and the following 4 new families and 2 new subfamilies: Mylonchulidae (Mylonchulinae and Sporonchulinae), Cobbonchidae, Anatonchidae and Iotonchidae.
30 citations
TL;DR: It is suggested that plant growth and the nematode population density and reproductive rate are the end result of numerous interactions in this ecological situation and that environmental stress, by lowering the tolerance of the plant to the Nematode, may be the basis for some of the more serious plant failures due to nematodes.
Abstract: The influence of nematode numbers on reproduction and invasion of M. javanica and on the root growth of the host, tomato, are described for different environmental conditions of soil particle size, nutrient and temperature. Under the particular experimental conditions, the environmental factors influenced the plant and the nematode in its soil and parasitic phases. The rate of root growth probably affected the reproduction of the nematode and in turn the nematode probably influenced root growth. Invasion, reproduction and development were also influenced by population density of nematodes. It is suggested that plant growth and the nematode population density and reproductive rate are the end result of numerous interactions in this ecological situation and that environmental stress, by lowering the tolerance of the plant to the nematode, may be the basis for some of the more serious plant failures due to nematodes.
TL;DR: The data suggest that shorter nematodes with smaller "a" ratios, a wider range of "c" ratios and stylet lengths, and lower vulva percentages are correlated with localities closer to the equator that have high amounts of precipitation and high mean temperatures.
Abstract: The influence of geographic location, latitude, mean annual precipitation, and temperature, on 75 populations of Xiphinema americanum sensu lato was studied. Twenty-one populations were from Florida, 17 from 9 other states and Canada, 20 from 8 European countries, 8 from Central and South America, 8 from Africa, and 1 from Asia. Criteria for comparison were as follows: female body length, vulva position (expressed as percentage of body length), de Manian "a" and "c" ratios (body length divided by body width or tail length), stylet length, tail shape, and the ratio between tail length and body width at the anus (T/BWA Ratio). European populations mainly from Mediterranean countries were distinct from other populations primarily in "a" ratio, vulva position, and tail shape, criteria which could be considered adequate for regarding these populations as a discrete species. The data further suggest that shorter nematodes with smaller "a" ratios, a wider range of "c" ratios and stylet lengths, and lower vulva percentages are correlated with localities closer to the equator that have high amounts of precipitation and high mean temperatures.
TL;DR: A linear relationship was shown to exist between increasing numbers of zoospores and the incidence of the fungus disease in nematodes in vitro, and this fungus isolate was not a very effective biological control agent.
Abstract: A phycomycetous fungus, Catenaria anguillulae, a parasite of phytonematodes, was isolated from greenhouse soil and cultured. Zoospores of the fungus were tested for virulence to the nematodes, Panagrellus redivivus and Ditylenchus dipsaci. A linear relationship was shown to exist between increasing numbers of zoospores and the incidence of the fungus disease in nematodes in vitro. The fungus developed more rapidly at 28° C than at the lower temperatures. D. dipsaci was less susceptible to attack from the fungus than P. redivivus. A pH of 9 and a low salt concentration favored the rapid development of the fungus in nematodes. Many more zoospores were required in sand and soil to achieve the same incidence of the disease than in liquid cultures. The tests indicated that this fungus isolate was not a very effective biological control agent.
TL;DR: Individual females laid more eggs when there were 4 in a petri dish than when they were alone, and the different hosts tested did not affect the average number of eggs laid per female but did affect the rate eggs were laid.
Abstract: Aphelerachus avenae feeding on fungal cultures in petri dishes responded to adverse conditions by slowing egg laying not by laying fewer eggs. The females required a continuous supply of food to produce eggs; after starving they resumed egg laying when given food and laid at the same rate as nonstarved individuals and for the same length of time. The different hosts tested did not affect the average number of eggs laid per female but did affect the rate eggs were laid. Individual females laid more eggs when there were 4 in a petri dish than when they were alone.
TL;DR: A key is given separating 36 species in the genus Pratylenchus by having three head annules, no males, a long narrow oesophageal overlap and a broadly rounded smooth tail tip.
Abstract: Pratylenchus pinguicaudatus n. sp., associated with wheat at Rothamsted, is distinguished from other Pratylenchus species by having three head annules, no males, a long narrow oesophageal overlap and a broadly rounded smooth tail tip. A key is given separating 36 species in the genus.
TL;DR: Die Dichte des Befalles der Wirtspflanzen und die Wurzeldicke sind die wesentlichen Faktoren, die das Geschlechterverhaltnis von Heterodera schachtii beeinflussen, und scheint die geschlechtliche Determination selbst nicht unter dem direkten Einflus der Umgebung zu stehen
Abstract: Die Dichte des Befalles der Wirtspflanzen und die Wurzeldicke sind die wesentlichen Faktoren, die das Geschlechterverhaltnis von Heterodera schachtii beeinflussen. Dabei scheint die geschlechtliche Determination selbst nicht unter dem direkten Einflus der Umgebung zu stehen. Zwar nimmt unter Mangelbedingungen die Zahl der Mannchen entsprechend dem Geschlechterverhaltnis scheinbar zu. Tatsachlich aber sinkt der absolute Anteil der zur Entwicklung kommenden Weibchen ab. Diese Abnahme der Weibchenmenge ist immer korreliert mit einer typischen Zunahme des Anteiles stagnierender und toter Larven aller Stadien. Als deren Ursache kann gelten, das das Weibchen fur eine normale Entwicklung ein Minimalvolumen von 0,070 mm 3 Wurzelmaterial bzw. 0,0037 mm 3 Riesenzellmaterial, das Mannchen dagegen nur 0,0011 mm 3 Wurzelmaterial benotigt. Darum sind pro Einheit Wurzelgewicht (1 mg) maximal nur 3,6 Weibchen, dagegen aber 30 Mannchen entwicklungsfahig. Trotz dieser groseren Entwicklungsmoglichkeiten fur die Mannchen nehmen bei uber 6 Nematoden/mg Wurzel ansteigenden Befallsdichten lediglich die Anteile an stagnierenden und toten Larven zu und die Zahl der Weibchen im Verhaltnis zur Menge der eingewanderten Larven kontinuierlich ab. Es werden weitere Beobachtungen uber die Lange der Mannchen (n = 586. 0,54-1,70 mm) und das Riesenzellsystem besprochen und eine Methode zur Kultivierung der infizierten Wirtspflanzen in Losungen angegeben.
TL;DR: The effect of the growth-regulating agent ethrel - a synthetic precursor of ethylene in plant tissue - was examined on tomato seedlings infected with the root knot nematode Meloidogyne javanica and it was suggested that ethylene is related to the pathogenic processes induced by the root Knot Nematode.
Abstract: The effect of the growth-regulating agent ethrel - a synthetic precursor of ethylene in plant tissue - was examined on tomato seedlings infected with the root knot nematode Meloidogyne javanica. The chemical was found to increase the fresh weight of plant galls induced by the nematode in a linear correlation with its dosage levels. The effect of ethrel on root knot nematode pathogenicity was most manifest at a soil temperature of 20° C and during maturation of the female within the gall. It is suggested that ethylene is related to the pathogenic processes induced by the root knot nematode.
TL;DR: Untersuchungen auf einem schwachsauren Sandboden zeigten, das Nematoden der Gattung Trichodorus im Vergleich zu Tylenchorhynchur and Pratylenchur sowie zur Nem atodenfauna auch tieferer Bodenschichten angesehen werden konnen.
Abstract: Untersuchungen auf einem schwachsauren Sandboden zeigten, das Nematoden der Gattung Trichodorus im Vergleich zu Tylenchorhynchur und Pratylenchur sowie zur Nematodenfauna insgesamt als ausgesprochene Bewohner auch tieferer Bodenschichten angesehen werden konnen. Fur die Mannchen der beiden erfasten Trichodorur-Arten wurde eine unterschiedliche Verteilung im Bodenprofil festgestellt. Die absolut hochsten Dichten wurden fur T. viruliferus zwischen 10 und 40 cm ermittelt, fur T. pachydermus dagegen zwischen 30 und 60 cm. Der prozentuale Anteil von T. pachydermn.r an der gesamten Anzahl von Mannchen steigt mit zunehmender Bodentiefe sichtlich an. Nach dem Anteil der Mannchen zu urteilen, ergeben sich also deutliche Unterschiede in der vertikalen Besiedlung des Bodens zwischen beiden Arten. Vertikalwanderungen konnten mit Hilfe der angewandten Methoden nicht nachgewiesen werden.
TL;DR: The sex ratio of Heterodera rostochiensis on tomato was increased not only by high larval population density, but also by the presence of the three plant pathogenic fungi: Rhizoctonia solani, Verticillium alboatrum and grey sterile fungus.
Abstract: The sex ratio of Heterodera rostochiensis on tomato was increased not only by high larval population density, but also by the presence of the three plant pathogenic fungi: Rhizoctonia solani, Verticillium alboatrum and grey sterile fungus. The sex ratio of H. rostochiensis increased with an increase in the fungus inoculum.
TL;DR: Mumtazium n.
Abstract: Mumtazium n. gen. belongs in Utahnematinae Siddiqi, 1969 and is characterized by having small amphids with oval apertures; large, asymmetrical spear bearing dorylaimid extension; muscular oesophagus; opisthodelphic gonad and a long, filiform tail. M. mumtazae n. sp. is described from soil in Papyrus Swamp, Namulonge, Uganda, and is the only species in the genus. Laimydorus n. gen. is proposed to accommodate those species of Dorylaimus sensu lato which lack longitudinal ridges over the body. It differs from Mesodorylaimus in having a double spear-guiding ring, longitudinal vulva; elongate, multicellular ovaries; and males having numerous contiguous, supplementary papillae and pre-rectum extending well beyond the region of the supplements.
TL;DR: The type locality for the three species is Himatangi Beach, Manawatu, New Zealand, in dune sand under Ammophila arenaria (L.) Link.
Abstract: Mononchoider potohikus n. sp. (Diplogasteridae) is distinguished from other species of the genus by its short tail (c' ≃ 0.9 in mature specimens); the first stage juveniles are rhabditoid (in that oesophagus lacks distinct tri-radiate valve in median bulb), subsequent stages diplogasteroid; prerectum present; tuboid supplements present in males. Allometric growth coefficients are given for post-embryonic development, based on a culture population. Mesorhabditis littoralis n. sp. (Rhabditidae) females are morphologically similar to those of M labiata (Volk, 1950) but may be distinguished by the possession of oesophageal bulbs of similar size; males have an apparently leptoderan bursa. Panagrolaimus australis n. sp. (Panagrolaimidae) is closest to P. rigidus (Schneider, 1866) but is readily distinguished by the location of phasmids near the cloaca. The type locality for the three species is Himatangi Beach, Manawatu, New Zealand, in dune sand under Ammophila arenaria (L.) Link.
TL;DR: From the results a treatment has been devised for separating Rhabditis spp.
Abstract: Ditylenchus dipsaci, Hemicycliophora arenaria, Meloidogyne hapla, 'Pratylenchu.r vulnus, Rhab. ditis spp. and Tylenchulus semipenetrans have been compared with respect to osmotic stress. After 24 hr in various concentrations of hypertonic electrolyte (NaCl) or non-electrolyte (urea), they were transferred to distilled water and their percentage mobility calculated. Their physiological responses varied considerably and from the results a treatment has been devised for separating Rhabditis spp. from D. dipsaci. The data are discussed with reference to possible mechanisms of osmotic tolerance and control and to differences in the biology of the nematodes.
TL;DR: The body cuticle, epidermis and epidermal body pores, body musculature, stomatal wall, odontostyle, Stylet protractor muscles, stylet retractor muscles, four spherical structures and the oesophagus are described from and illustrated with electron micrographs of ultrathin sections.
Abstract: The body cuticle, epidermis and epidermal body pores, body musculature, stomatal wall, odontostyle, stylet protractor muscles, stylet retractor muscles, four spherical structures and the oesophagus are described from and illustrated with electron micrographs of ultrathin sections. The oesophago-intestinal junction is described from paraffin sections. Seven layers of the cuticle are described and micrographed. An infracuticular layer exists in the anterior part of the body which intermingles directly with layer 6 of the cuticle. The body of each lateral epidermal organ is completely embedded in one of the lateral chords, leading to a duct that opens exteriorly through a cuticular pore. The body musculature is of the polymyarian and coelomyarian type. A system of electron-dense structures is present in the contractile part of each muscle cell. The stomatal wall and the odontostyle do not differ much from those of X. index. The stylet protractor muscles do not merge with the tissue surrounding the stoma at any level. Four spherical bodies exist outside the protractor muscles at the base of the odontostyle. Five glands open into the lumen of the basal part of the oesophagus through cuticularized outlets. No nuclei were traced for the last pair of laterosubventral glands.
TL;DR: The numbers of larvae that invaded and of adult males and females produced in the roots of three hybrid potato varieties incorporating resistant genes from Solanum tuberosum s.sp.
Abstract: The numbers of larvae that invaded and of adult males and females produced in the roots of three hybrid potato varieties incorporating resistant genes from Solanum tuberosum s.sp. andigena, or S. multidissectum, or both were compared with those for a susceptible variety, Arran Banner, using inocula of larvae from nine populations of Heterodera rostochiensis. The numbers of larvae becoming adult were influenced by both the resistant host and the population used. Either (1) most larvae survived and many males and females were produced, (2) most larvae survived, but most became male and few became female, or (3) many larvae died, almost all the survivors became male and only a very few became female. These differences were probably determined by the size of the giant-cell groups the larvae were able to induce in the potato roots.
TL;DR: Although L. elongatus reproduced relatively slowly, reproduction was found to be continuous and females were still reproducing at the end of the experiments, so that the total reproduction appears comparable to that in other plant parasitic nematodes.
Abstract: Thirty-one plant species belonging to eleven botanical families were tested as possible hosts of L. elongatus. They included plants suspected as favourable for reproduction of the nematode, those which are known to be mainly infected with tomato black ring or raspberry ringspot viruses, or those immune to infection, and those used as virus assay plants or 'bait' plants to detect the presence of virus in the soil. There was, however, little connection between ability to support L. elongatus and susceptibility to the viruses it transmits. Strawberry, Fragaria vesca, was among the best hosts. F. vesca was subsequently used to study the life cycle of the nematode. The hatching time of L. elongatus eggs reported here (9-12 days) agrees closely with that in most other plant parasitic nematodes reported by various investigators. On the other hand, the rate of multiplication of L. elongatus found in this investigation was low compared with that in the closely related species, Xiphinema index, studied by other investigators. Thus, while L. elongatus on F. vesca increased about 20-fold over 4-6 months, X. index on fig (Ficus carica) increased more than 1,000 times over a comparable period. This low rate of multiplication of L. elongatus is the product of both a low rate of reproduction (about 1 egg/week) and a slow life cycle (about 19 weeks from female to female), as also found here. Although L. elongatus reproduced relatively slowly, reproduction was found to be continuous and females were still reproducing at the end of the experiments (16-23 weeks), so that the total reproduction appears comparable to that in other plant parasitic nematodes. This is because L. elongatus persists for a long time in the soil.
TL;DR: In this paper, a comparison of the feeding mechanisms of A. bicaudatus was made on the fungi, Pyrenochaeta terrestris, Sporobolomyces sp., Hansenula saturnus, and the alga, Stichococcus bacillaris.
Abstract: A comparison of the feeding mechanisms of A. bicaudatus was made on the fungi, Pyrenochaeta terrestris, Sporobolomyces sp., Hansenula saturnus, and the alga, Stichococcus bacillaris. The nematode fed briefly and the feeding mechanism, involving an exploration and penetration phase and an ingestion phase, was similar on all four microorganisms. A. bicaudatus removed the host cell contents mechanically and no injection of glandular secretions into the cell by the nematode was observed. The nematode oriented its stylet against the cell wall at a right angle to the cell surface and only a minimal lip contact with the cell surface was necessary for penetration. Metacorporal pulsations were associated with stylet protrusion and resulted from action of its radial muscles. Duration of feeding, number of thrusts required for penetration and rate of metacorporal pulsations varied with the organism used as food. Feeding on P. terrestris, Sporobolomyces sp., H. saturnus and S. bacillaris on an average lasted for 21, 28, 4 and 5 sec, respectively. A recurrent contraction and re-elongation of the tail region caused a back and forth movement of intestinal lumen contents.
TL;DR: Seedlings of nine pine species native to the Southeast were grown in 20-cm pots in the greenhouse and inoculated with eight species of endoparasitic nematodes, indicating a positive host-parasite relationship for a given nematode-pine combination.
Abstract: Seedlings of nine pine species native to the Southeast were grown in 20-cm pots in the greenhouse and inoculated with eight species of endoparasitic nematodes. Completion of life cycles after 6 to 9 months indicated a positive host-parasite relationship for a given nematode-pine combination. Lance (Hoplolaimus galeattts), pine cystoid (Meloidodera floridensis), and root-lesion (Pratylenchus brachyurus) nematodes reproduced on most of the pines tested. None of the pines were hosts for the remaining five nematode species tested: Meloidogyne arenaria, M. hapla, M. incognita, M. javanica, and Pratylenchus zeae.
TL;DR: Une etude cytologique d'Heterodera oryzae et HeterodERA sacchari a demontre qu' H, oryzAE etait une espece diploide possedant 18 chromosomes et H. saccharl' une esPEce triploides a 27 chromosomes.
Abstract: Une etude cytologique d'Heterodera oryzae et Heterodera sacchari a demontre qu' H, oryzae etait une espece diploide possedant 18 chromosomes et H. saccharl' une espece triploide a 27 chromosomes. Pendant l'ovogenese d'H. oryzae le nombre de chromosomes est reduit a neuf alors qu'H. racchuri a une maturation d'un type mitotique et le nombre de chromosomes n'est pas reduit. Des inoculations monolarves ont demontre qu'H. oryzae etait une espece amphimictique et H. sacchari' une espece parthenogenetique.