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1.  Nematode Population and Community Dynamics in Soybean-Wheat Cropping and Tillage Regimes 
Journal of Nematology  1984;16(4):379-386.
The nematode community structures of various soybean-wheat regimes and of a single-cropped, conventionally tilled soybean regime were studied at two sites in Tennessee. Each of the 100 nematode species identified in the study was placed in one of five trophic groups, the most diverse being plant parasites (31 species), followed by Dorylaimida (26 species), bacterivores (23 species), fungivores (15 species), and predators (5 species). No significant differences in overall diversity and dominance among treatments and trophic groups were found. Densities of Heterodera glycines Ichinohe infective juveniles were significantly higher in single-cropped, conventionally tilled soybeans in July. When data were subjected to ordination analysis, it was shown that plant-parasitic nematode communities produced an aggregation of conventionally tilled, single-cropped soybean plots when compared to all double-cropped treatments. Ordination of overall nematode communities yielded similar results.
PMCID: PMC2618411  PMID: 19294042
community ordination techniques; ecology; Filenchus species; Glycine max; Heterodera glycines; soybean cyst nematode; no-till; Triticum aestivum; trophic groups
2.  Heydenius dominicus n. sp. (Nematoda: Mermithidae), a Fossil Parasite from the Dominican Republic 
Journal of Nematology  1984;16(4):371-375.
Heydenius dominicus n. sp. is described as a new species of fossil mermithid nematode from Dominican Republic amber. The species is represented by two specimens of parasitic juveniles that left their insect host and became embedded in the resin. The nematodes are associated with an adult male limoniid (Diptera: Limoniidae) and an adult female mosquito (Diptera: Culicidae). The parasites are thought to have emerged from the mosquito host. This is the first report of a fossil mermithid from a Neotropical area.
PMCID: PMC2618410  PMID: 19294040
culicid host; parasitic nematode; fossil
3.  Expression of Resistance in Peanuts to Pratylenchus brachyurus: Impact on Screening for Resistance 
Journal of Nematology  1984;16(4):404-406.
PMCID: PMC2618409  PMID: 19294049
plant resistance; lesion nematodes; Arachis hypogaea
4.  Effect of Temperature on the Development of Thelastoma bulhoesi (Oxyurata, Thelastomatida) and Other Nematodes 
Journal of Nematology  1984;16(4):355-360.
Embryonation of Thelastoma bulhoesi was monitored at eight temperatures between 0 and 35 C. Cell division did not occur below 15 C or at 35 C. Development was most rapid at 25 and 36 C. The effect of temperature on the rate of embryological development of T. bulhoesi at different stages was measured using the temperature coefficient, Q₁₀. The developmental temperature response curve obtained for T. bulhoesi was similar to enzyme temperature response curves. Our evidence supports the thesis that nematode embryonation, as affected by temperature, varies between species and between stages of development.
PMCID: PMC2618408  PMID: 19294037
temperature coefficient; Q₁₀
5.  Rangeland Grasses as Hosts of Meloidogyne chitwoodi 
Journal of Nematology  1984;16(4):399-402.
PMCID: PMC2618407  PMID: 19294047
Columbia root-knot nematode; histopathology; host response; reproduction; orchardgrass; wild ryegrass; wheatgrasses
6.  Flowering Delay in Flue-cured Tobacco Infected with Meloidogyne Species 
Journal of Nematology  1984;16(4):402-404.
PMCID: PMC2618406  PMID: 19294048
flowering; root-knot nematodes; M. incognita; M. arenaria; M. javanica; Nicotiana tabacum L.; microplots; nematicides; ethoprop (Mocap); D-D (Shell D-D)
7.  New and Known Species of Pratylenchus Filipjev, 1936 (Nematoda: Pratylenchidae) from Haryana, India, with Remarks on Intraspecific Variations 
Journal of Nematology  1984;16(4):360-367.
Two new monosexual and one bisexual species Pratylenchus Filipjev, 1936 collected from Haryana state of India are described and illustrated. The primary distinguishing features of these species are Pratylenchus microstylus n. sp.: L = 331-458 μm, spear = 11 or 12 μm; Pratylenchus cruciferus n. sp.: L = 648-793 μm, central core of lateral fields with oblique lines, hemizonid 2-8 annules anterior to excretory pore; Pratylenchus ekrami n. sp.: spear = 11-13 μm, spermatheca oblong, post vulval uterine sac with differentiated cells, tail with 26-40 annules, males abundant. Studies on intraspecific variations of P. cruciferus, P. ekrami, and P. coffeae (Zimmermann, 1898) Goodey, 1951 revealed that spear length and value of 'V' are the least variable characters. Body length and size of post vulval uterine sac varies to varying degrees in different species. Shape of median bulb in P. ekrami, number of incisures in P. coffeae, and tail shape in P. ekrami and P. coffeae exhibit the greatest amount of intraspecific variations. P. zeae Graham, 1936 and P. thornei Sher & Allen, 1953 are the other species collected during the present studies.
PMCID: PMC2618405  PMID: 19294038
taxonomy; morphology; Pratylenchus microstylus; P. cruciferus; P. ekrami
8.  Pararotylenchus hopperi nomen novum 
Journal of Nematology  1984;16(4):398-399.
PMCID: PMC2618404  PMID: 19294046
junior primary homonym; Tylenchorhynchus
9.  Pathogenicity and Reproduction of Hoplolaimus columbus and Meloidogyne incognita on 'Davis' Soybean 
Journal of Nematology  1984;16(4):349-355.
The effects of initial populations of Hoplolaimus columbus and Meloidogyne incognita on growth and yield of Davis soybean were determined for 1980 and 1981 in microplots and H. columbus in field tests in 1981. M. incognita suppressed yield in microplots both years and H. columbus in 1980. Maximum suppression of dry pod weight by M. incognita was 45% and by H. columbus 35%. The relationship of yield vs. nematode population at planting time was described by a declining exponential model. Maximum reproductive rates for M. incognita and H. columbus were 67.0 and 4.7, respectively, and were inversely proportional to initial population level. Nematode reproductive rates, survival ability, and feeding habits suggest species specific life strategies in the ecological community.
PMCID: PMC2618403  PMID: 19294036
ecology; Glycine max; lance nematode; root-knot nematode; reproduction threshold
10.  A New Gall-Forming Species of Anguina Scopoli, 1777 (Nemata: Anguinidae) on Bluegrass, Poa annua L., from the Coast of California 
Journal of Nematology  1984;16(4):386-392.
Anguina pacificae n. sp. is described and illustrated from stem galls on bluegrass, Poa annua L., from golf courses along coastal California. The females are characterized by constrictions in the anterior and posterior connections of the isthmus with the respective parts of the esophagus, the long multicellular columella, and the sharply pointed tail tip. Males are dorsally curved after death; body width is increased markedly after 13 annuli in both sexes, and the tail is conical and with an acute terminus.
PMCID: PMC2618402  PMID: 19294043
taxonomy; columella; galls; scanning electron microscopy
11.  Influence of Nacobbus aberrans Densities on Growth of Sugarbeet and Kochia in Pots 
Journal of Nematology  1984;16(4):393-395.
PMCID: PMC2618401  PMID: 19294044
false root-knot nematode; Beta vulgaris; Kochia scoparia; modeling; tolerance; reproduction
12.  Cropping Effects of Marigolds, Corn, and Okra on Population Levels of Meloidogyne javanica and on Carrot Yields 
Journal of Nematology  1984;16(4):396-398.
PMCID: PMC2618400  PMID: 19294045
root-knot nematode; Tagetes patula; Zea mays; Abelmoschus esculentus; Daucus carota; rotation
13.  Reproductive Isolation and Taxonomic Differentiation of Romanomermis culicivorax Ross and Smith, 1976 and R. communensis Galloway and Brust, 1979 
Journal of Nematology  1984;16(4):375-379.
The infertility of hybrid progeny of Romanomermis communensis and R. culicivorax supports their retention as distinct species. Their taxonomic separation on the basis of morphometric data and possession of a cone-shaped spicule guide is rejected. However, differences in the enzyme patterns of peptidase and phosphoglucomutase and the restriction fragment length differences in repetitive genomic DNA provide sensitive diagnostic characters that confirm the differentiation into two species.
PMCID: PMC2618399  PMID: 19294041
reproductive isolation; Romanomermis communensis; R. culicivorax; taxonomy
14.  Variability in Reproduction of Four Races of Meloidogyne incognita on Two Cultivars of Soybean 
Journal of Nematology  1984;16(4):368-371.
Variability in the reproduction of the four races ofMeloidogyne incognita on the soybean cuhivars Pickett 71 and Centennial was studied in growth chamber experiments. Analysis of variance in the number of eggs produced by the races 6 weeks after the plants had been inoculated with 5,000 eggs of each race revealed that the nematode race by soybean cultivar interaction was highly significant (P = 0.001). Races 1, 3, and 4 produced from about 5,000 to 15,000 eggs per root system on Pickett 71 and only from about 300 to 600 eggs per root system on Centennial. In contrast, race 2 produced about 8,000 eggs per root system on Centennial and about 1,200 eggs per root system on Pickett 71. In a second experiment, in which the plants were inoculated with 2,000 second-stage juveniles, race 1 and race 2 produced about 13,000 and 3,000 eggs per root system, respectively, on Pickett 71 and about 600 and 10,000 eggs per root system, respectively, on Centennial. The results suggest that M. incognita resistance in soybean is race-specific.
PMCID: PMC2618398  PMID: 19294039
Meloidogyne incognita; root-knot nematodes; resistance; Glycine max
15.  Effect of Phytotoxin from Nematode-induced Pinewilt on Bursaphelenchus xylophilus and Ceratocystis ips 
Journal of Nematology  1984;16(3):297-303.
A phytotoxic extract from Pinus sylvestris infected with Bursaphelenchus xylophilus inhibited growth of the blue-strain fungus Ceratocystis ips and caused temporary paralysis in vitro of B. xylophilus. Although the nematodes recovered from paralysis, final population size of B. xylophilus was suppressed by the toxin. Extracts from noninfected P. sylvestris affected neither the fungus nor the nematode.
PMCID: PMC2618397  PMID: 19294025
phytoalexin; nematode; terpenoids
16.  Effect of Soil Temperature on Reproduction of Meloidogyne chitwoodi and M. hapla Alone and in Combination on Potato and M. chitwoodi on Rotation Plants 
Journal of Nematology  1984;16(3):309-312.
Meloidogyne chitwoodi developed and reproduced more rapidly than M. hapla in potato roots at 15, 20, or 25 C when both species of nematodes were inoculated simultaneously at 250 or 1,000 juveniles of each. At 30 C significantly more M. hapla than M. chitwoodi females were found at the lower inoculum level after 41 days. More M. chitwoodi than M. hapla juveniles were extracted from soil at 15, 20, and 25 C, but only at the lower inoculum level at 30 C. Potato was considered a more suitable host for M. chitwoodi than M. hapla because of M. chitwoodi's greater reproduction at 15, 20, and 25 C. Corn and wheat cultivars tested supported M. chitwoodi reproduction at temperatures of 10, 15, 20, and 25 C, but fewest eggs were produced on these plants at 20 C. Temperatures of 10 to 25 C had little influence on the low reproduction of M. chitwoodi on four alfalfa cultivars. M. chitwoodi reproduced on the alfalfa entry Mn PL9HF.
PMCID: PMC2618396  PMID: 19294027
Columbia root-knot nematode; northern root-knot nematode; alfalfa; wheat; corn
17.  Gastromermis kolleonis n. sp. (Nematoda: Mermithidae), a Parasite of Midges (Chironomus sp. Chironomidae) from Argentina 
Journal of Nematology  1984;16(3):252-255.
Gastromermis kolleonis n. sp. (Nematoda: Mermithidae) is described from the Arroyo Saldan River in Córdoba, Argentina. This species parasitizes midges of the genus Chironomus (Chironomidae: Diptera). It is distinguished from other members of the genus by the presence of six longitudinal chords, vulval flaps, degree of ventral displacement of the mouth, and size and shape of the spicule and amphids.
PMCID: PMC2618395  PMID: 19294020
mermithid nematode; chironomid host; taxonomy
18.  Comparison of Five Methods for Measuring Nematode Volume 
Journal of Nematology  1984;16(3):343-347.
PMCID: PMC2618394  PMID: 19294034
nematode volume measurement; nematode morphometrics; digital morphometrics; nematode water content
19.  Description of Meloidoderita polygoni n. sp. (Nematoda: Meloidoderitidae) from USA and Observations on M. kirjanovae from Israel and USSR 
Journal of Nematology  1984;16(3):265-282.
Meloidoderita polygoni n. sp. is described and illustrated from roots of smartweed (Polygonum hydropiperoides) from Beltsville, Maryland. This new species is similar to M. kirjanovae but differs especially in having larger spines on the cystoid bodies, females with the anus much closer to the vulva, and more posterior excretory pore. M. polygoni differs from M. safrica particularly in having females with a shorter stylet, a DGO much closer to base of stylet, greater distance between vulva and anus, and larger cystoid bodies. LM and SEM observations showed only three incisures in lateral fields of juveniles and males and no bursa in males. Morphometric data and illustrations are given for M. kirjanovae from mint (Mentha longifolia) in Israel and some details on a limited number of specimens from Armenian SSR. LM examination of juveniles from both these areas indicated only three incisures in lateral fields. Males from Israel had no detectable bursa and appeared to have only three incisures in lateral fields. (Males from Armenian SSR not observed.)
PMCID: PMC2618393  PMID: 19294022
taxonomy; morphology; new species; SEM ultrastructure; smartweed; Polygonum hydropiperoides; mint; Mentha Iongifolia; hosts; distribution
20.  Technique for Axenizing Nematodes 
Journal of Nematology  1984;16(3):348.
PMCID: PMC2618392  PMID: 19294035
culturing; method
21.  Heterodera raskii n. sp. (Heteroderidae: Tylenchina), a Cyst Nematode on Grass, from Hyderabad, India 
Journal of Nematology  1984;16(3):213-216.
Heterodera raskii n. sp. is described and illustrated from specimens collected from roots of bulb grass, Cyperus bulbosus, in Hyderabad, India. The new species belongs to the 'goettingiana' group and differs from closely related H. cyperi by the elongate ovoid shaped cysts and females, greater fenestral length, width, vulval slit, and absence of egg sac. The stylet knob shape was round in second-stage juveniles and posteriorly sloping in females and males of H. raskii n. sp., while it was anteriorly directed in second-stage juveniles and spherical in females and males of H. cyperi.
PMCID: PMC2618391  PMID: 19294013
taxonomy; morphology; bulb grass; Cyperus bulbosus
22.  Response of Peach Seedlings to Infection by the Root Lesion Nematode Pratylenchus penetrans under Controlled Conditions 
Journal of Nematology  1984;16(3):317-322.
Twenty-one open pollinated populations of peach rootstock seedlings were evaluated for their response to infection by the root lesion nematode, Pratylenchus penetrans, over a period of 98 days. Nematode-infected peach seedling populations were shorter in plant height and had less shoot weight but more dry root weight than nematode-free controls. Rootstock differences were demonstrated for nematode increase over the 98-day period, and average total numbers of nematodes in soil and roots. Rootstocks were classified into three groups differing in total nematode population levels, ratio of nematode increase, and the number of nematodes per root. The heritable nature of rootstock response to nematodes was evident. Rootstocks showing the lowest response to nematode infection included Tzim Pee Tao, Rutgers Red Leaf, and two progenies of a cross of these two rootstocks.
PMCID: PMC2618390  PMID: 19294029
Prunus persica; Pratylenchus penetrans; nematode populations; rootstock variability
23.  Distribution of Tylenchulus semipenetrans in a Texas Grapefruit Orchard 
Journal of Nematology  1984;16(3):313-317.
Distribution of the citrus nematode (Tylenchulus semipenetrans) was studied over 18 months in a 6-year-old orchard of grapefruit (Citrus paradisi cv. Ruby Red) on sour orange (C. aurantium) rootstock. The 1.8-ha orchard was under chemical weed control, no tillage, and flood irrigation. Highest numbers of nematodes were found in the top 15 cm of the soil profile. The nematode population peaked in April and declined to lowest levels in August and September. Numbers of nematodes were negatively correlated (r = -0.95) with soil temperatures above 29 C. Soil populations of nematodes were not correlated with soil moisture. The distribution of the nematode in the field was highly skewed and was described by a negative binomial. In this 1.8-ha block, five soil samples of 12 cores each would provide an estimate within 20% of the true nematode population mean with 95% confidence.
PMCID: PMC2618389  PMID: 19294028
citrus nematode; population dynamics; sampling; sour orange
24.  Changes in the Reproduction of Heterodera glycines on Different Lines of Glycine max 
Journal of Nematology  1984;16(3):304-309.
Selection for ability of soybean cyst nematode (SCN), Heterodera glycines, to reproduce on soybeans with different sources of resistance divides some SCN race 4 field populations into two distinct subpopulations. These subpopulations reproduce well on 'Bedford' and plant introduction (PI) 88788 or PI 89772 and PI 90763 but not on both pairs of soybean lines. The ability of these subpopulations to reproduce on the four soybean lines was reversed by changing the soybean line used as a host during a second cycle of selection. When SCN populations previously selected for reproduction on Bedford and PI 88788 were selected for their ability to reproduce on D72-8927 and J74-88, the ability of these populations to reproduce on Bedford and PI 88788 decreased significantly and their ability to reproduce on PI 89772 and PI 90763 increased significantly. Conversely, when SCN populations, previously selected for reproduction on P189772 and P190763, were selected for their ability to reproduce on Bedford, the reproduction of these populations on Bedford increased significantly and reproduction on PI 89772 and PI 90763 decreased significantly. Selection for ability of a SCN race 4 field population to reproduce on soybean lines derived from SCN race 4 resistant PIs resulted in the same division of the field population into two distinct subpopulations. These data substantiate earlier proposals to rotate cultivars with different genes for SCN resistance as a means of managing SCN populations.
PMCID: PMC2618388  PMID: 19294026
races; resistance; soybean; soybean cyst nematode
25.  Comparative Electrophoretic Analyses of Soluble Proteins from Heterodera glycines Races 1-4 and Three Other Heterodera Species 
Journal of Nematology  1984;16(3):332-340.
Modified polyacrylamide gel and SDS-polyacrylamide gel electrophoretic systems using a low molarity tris-HCl buffer and equal pH of homogenizing buffer and stacking gel provided improved stacking for separation of soluble proteins from Heterodera schachtii, H. trifolii, H. lespedezae, and H. glycines races 1, 2, 3, and 4, compared with previous studies with cyst nematodes, The four Heterodera species were easily distinguished using the polyacrylamide gel system, but H. trifolii and H. lespedezae had similar protein patterns. H. glycines races were not separable by that system. The SDS-polyacrylamide gel system produced different protein patterns for all four Heterodera species although H. trifolii and H. lespedezae differed by only a single band, suggesting that these two may be subspecifically related. A protein band unique to H. glycines races 3 and 4 was not detected in SDS-polyacrylamide gel profiles from races 1 and 2. Molecular weight determinations were 55,000 for distinctive proteins in profiles of H. trifolii and 75,000 for H. glycines races 3 and 4.
PMCID: PMC2618387  PMID: 19294032
electrophoresis; soybean cyst nematode; Heterodera lespedezae; Heterodera schachtii; Heterodera trifolii

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