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2.  Root Growth of Susceptible and Resistant Potato Cultivars and Population Dynamics of Globodera rostochiensis in the Field 
Journal of Nematology  1986;18(4):501-504.
Globodera rostochiensis population densities and potato root growth were measured in field plots of one susceptible and two resistant potato cultivars. Root growth and nematode densities were estimated from soil samples taken at three depths between plants within the rows, three depths 22.5 cm from the rows, and at two depths midway between rows (furrows). Four weeks after plant emergence (AE), nematode densities in the rows had declined 68% in plots of the susceptible cultivar and up to 75% in plots of both resistant cultivars. Significant decline in nematode densities in the furrows 4 weeks AE occurred only in plots of the susceptible cultivar. Total decline in nematode density in fallow soil was 50%, whereas in plots of the resistant cultivars, decline was more than 70% in the rows and more than 50% in the furrows. Nematode densities increased in the rows of the susceptible cultivar but declined in the furrows. We conclude that G. rostochiensis decline or increase is correlated with host resistance and the amount of roots present at any particular site.
PMCID: PMC2618597  PMID: 19294219
potato root growth; population decline; Globodera rostochiensis; root diffusate; Solanum tuberosum
3.  Soybean and Maize Cropping Models for the Management of Meloidogyne incognita in the Coastal Plain 
Journal of Nematology  1986;18(4):451-458.
Models are presented to describe the influence of rotations of Meloidogyne incognita-susceptible cultivars, resistant cultivars, and maize on postharvest abundance of M. incognita juveniles in the soil. Depending on initial densities of juveniles, monocultured regimes reached equilibrium densities after a few years of 287, 40, and 10 juveniles per 10 cm³ soil for susceptible soybean, resistant soybean, and maize, respectively. Yearly changes in the population density of juveniles due to rotation of these crops were simulated by iterative substitution of the model equations for each crop. A maximum density of 319 per 10 cm³ soil was reached following a susceptible cultivar in a susceptible-resistant soybean rotation. Soybean yield loss estimates are presented for monocultured regimes and for various rotations with maize.
PMCID: PMC2618596  PMID: 19294210
crop rotation; Glycine max; Meloidogyne incognita; southern root-knot nematode; population dynamics; resistance; Zea mays
4.  Soybean Yield as Related to Rates of 1,3-Dichloropropene Applied at Planting for Management of Root-Knot Disease 
Journal of Nematology  1986;18(4):464-467.
1,3-Dichloropropene (1,3-D) at rates of 17.2 to 51.6 liters/ha applied 3 days preplant or at planting significantly (P < 0.05) reduced the amount of galling on roots of soybean grown in sites infested with Meloidogyne incognita or M. arenaria. Populations of M. incognita second-stage juveniles at harvest were significantly (P < 0.05) reduced by all treatments. Only the 51.6-liters/ ha treatments and a 3-day preplant 34.4-liters/ha application significantly reduced at-harvest juvenile infestations of M. arenaria. Equations (P < 0.001) relating soybean yield and 1,3-D dosage indicated soybean phytotoxicity at the upper range of the nematicide rates. The maximum yield response was predicted at 40 liters/ha applied 3 days preplant at both infestation sites. Maximum yield response was predicted with 30 liters/ha applied at planting to M. incognita-infested soil and from 25 liters/ha applied at planting to M. arenaria-infested soil. Application of economic factors suggested that management of M. incognita may be cost effective with at-plant treatments of low rates of 1,3-D. Yield responses of M. arenaria-infected soybean exposed to similar treatments were insufficient to justify their use at prevailing prices.
PMCID: PMC2618595  PMID: 19294212
Meloidogyne incognita; Meloidogyne arenaria; nematicide; Glycine max
5.  Meloidogyne hispanica n. sp. (Nematoda: Meloidogynidae), the 'Seville Root-Knot Nematode' 
Journal of Nematology  1986;18(4):520-532.
Meloidogyne hispanica n. sp. is described and illustrated from specimens obtained from peach rootstock, Prunus persica silvestris Batsch, from the Seville district of Spain. The perineal pattern of the female is oval shaped to rectangular with low dorsal arch and often widely spaced lateral lines with fringe-like striae. The stylet, 14.1 μm long, has broad, distinctly set off knobs. Males have a high, rounded head cap that slopes posteriorly. Labial disc and medial lips are fused to form elongate lip structures. The robust styler, 23.5 μm long, has large, rounded knobs that are slightly set off from the shaft. Mean second-stage juveniles length is 392.6 μm. The truncate head region is generally not annulated. The distinctly rounded and raised labial disc and the crescent-shaped medial lips form dumbbell-shaped lip structures. The stylet, 11.1 μm long, has rounded, posteriorly sloping knobs. The slender tail, 46.4 μm long, has large irregular-sized annules in the posterior region and ends in a bluntly rounded tip. Tomato was a good host; tobacco, pepper, and watermelon were poor hosts; cotton and peanut were nonhosts. Meloidogyne hispanica n. sp. reproduces by mitotic parthenogenesis and has a somatic chromosome number of 2n = 33-36. The esterase pattern is unique among Meloidogyne species.
PMCID: PMC2618593  PMID: 19294222
taxonomy; morphology; new Meloidogyne species; host range; scanning electron microscopy; Prunus persica silvestris
6.  A Simulation Model of Heterodera schachtii Infecting Beta vulgaris 
Journal of Nematology  1986;18(4):512-519.
A simulation model of a single sugarbeet, Beta vulgaris L., plant infected by the sugarbeet cyst nematode, Heterodera schachtii Schmidt, was developed using published information. The model is an interactive computer simulation programmed in FORTRAN. Given initial population densities of the nematode at planting, the model simulates nematode population dynamics and the growth of plant tap and fibrous roots. The driving variable for nematode development and plant growth is temperature.
PMCID: PMC2618592  PMID: 19294221
sugarbeet; sugarbeet cyst nematode; simulation modeling; Beta vulgaris; Heterodera schachtii
7.  Retention of Resistance to Meloidogyne incognita in Lycopersicon Genotypes at High Soil Temperature 
Journal of Nematology  1986;18(4):491-495.
Lycopersicon glandulosum and L. peruvianum clones and L. esculentum cultivars 'VFN8' (resistant) and 'Rutgers' (susceptible) were tested for their resistance to Meloidogyne incognita (race l) at soil temperatures of 25 and 32 C. L. esculentum cv. VFN8 and L. peruvianum Acc. No. 128657, both of which possess the Mi gene, were resistant at 25 C but were susceptible at 32 C. L. glandulosum Acc. No. 126443 and L. peruvianum Acc. No. 270435, with combined resistance to M. hapla and M. incognita, and L. peruvianum Acc. Nos. 129152 and LA2157, with resistance to M. incognita, were highly resistant at both temperatures. In a second experiment three of these accessions under heat stress simulated by 32 C ambient and soil temperature retained a high level of resistance. Two clones of L. glandulosum Acc. No. 126440, with resistance to M. hapla, were moderately susceptible to M. incognita at 25 and highly susceptible at 32 C. M. incognita produced significantly (P = 0.01) more eggs on L. esculentum cv. Rutgers at 32 than at 25 C. This study supports the existence of genes other than the Mi gene that confer resistance to M. incognita and are functional at high soil temperatures.
PMCID: PMC2618591  PMID: 19294217
root-knot nematodes; resistance; Lycopersicon; soil temperature; tomato
8.  Effects of Interactions among Heterodera glycines, Meloidogyne incognita, and Host Genotype on Soybean Yield and Nematode Population Densities 
Journal of Nematology  1986;18(4):436-443.
The effects of host genotype and initial nematode population densities (Pi) on yield of soybean and soil population densities of Heterodera glycines (Hg) race 3 and Meloidogyne incognita (Mi) race 3 were studied in a greenhouse and field microplots in 1983 and 1984. Centennial (resistant to Hg and Mi), Braxton (resistant to Mi, susceptible to Hg), and Coker 237 (susceptible to Hg and Mi) were planted in soil infested with 0, 31, or 124 eggs of Hg and Mi, individually and in all combinations, per 100 cm³ soil. Yield responses of the soybean cultivars to individual and combined infestations of Hg and Mi were primarily dependent on soybean resistance or susceptibility to each species separately. Yield of Centennial was stimulated or unaffected by nematode treatments, yield of Braxton was suppressed by Hg only, and yield suppressions caused by Hg and Mi were additive and dependent on Pi for Coker 237. Other plant responses to nematodes were also dependent on host resistance or susceptibility. Population densities of Mi second-stage juveniles (J2) in soil were related to Mi Pi and remained constant in the presence of Hg for all three cultivars. Population densities of Hg J2 on the two Hg-susceptible Cultivars, Braxton and Coker 237, were suppressed in the presence of Mi at low Hg Pi.
PMCID: PMC2618590  PMID: 19294208
soybean cyst nematode; root-knot nematode; Glycine max; interaction; microplot; Heterodera glycines; Meloidogyne incognita
9.  Penetration and Postinfection Development of Meloidogyne incognita on Cotton as Affected by Glomus intraradices and Phosphorus 
Journal of Nematology  1986;18(4):429-435.
The influence of the vesicular-arbuscular mycorrhizal fungus Glomus intraradices (Gi) and superphosphate (P) on penetration, development, and reproduction of Meloidogyne incognita (Mi) was studied on the Mi-susceptible cotton cultivar Stoneville 213 in an environmental chamber at 28 C. Plants were inoculated with Mi eggs at planting or after 28 days and destructively sampled 7, 14, 21, and 28 days after nematode inoculation. Mi penetration after 7 days was similar in all treatments at either inoculation interval. At 28 days, however, nematode numbers were least in mycorrhizal root systems and greatest in root systems grown with supplemental P. The rate of development of second-stage juveniles to ovipositing females was unaffected by Gi or P when Mi was added at planting, but was delayed in mycorrhizal root systems when Mi was added 28 days after planting. Nematode reproduction was lower in mycorrhizal than in nonmycorrhizal root systems at both Mi inoculation intervals. Nematode reproduction was stimulated by P when Mi was added at planting, but was similar to reproduction in the low P nonmycorrhizal treatment when Mi was added 28 days after planting. Eggs per female were increased by P fertility when Mi was added at planting.
PMCID: PMC2618589  PMID: 19294207
endomycorrhizae; Gossypium hirsutum; Meloidogyne incognita; root-knot nematode; phosphorus; cotton
10.  A Comparison of Techniques Useful for Preparing Nematodes for Scanning Electron Microscopy 
Journal of Nematology  1986;18(4):479-487.
Second-stage juveniles of Meloidogyne incognita were prepared by several different techniques for scanning electron microscopy (SEM). Sequential fixation in the cold (4-8 C) was superior to rapid fixation at room temperature, glutaraldehyde and glutaraldehyde-formalin were better fixatives than formalin alone, and critical point drying with carbon dioxide or Freon gave similar results that were only slightly better than air drying with Freon. Freeze drying sequentially fixed nematodes from 100% ethanol in liquid propane produced the best preserved specimens with the fewest artifacts. Specimens of various free-living and plant-parasitic nematodes were prepared for SEM by freeze drying. This technique was adequate for most genera but unsatisfactory for a few. Although each genus may require a different procedure for optimum preservation of detail, sequential fixation with glutaraldehyde and freeze drying are comparable and often superior to commonly used techniques for preparing nematodes for SEM.
PMCID: PMC2618588  PMID: 19294215
critical point drying; fixation; fixatives; freeze drying; methods; morphology; Acrobeles sp.; Belonolaimus longicaudatus; Criconemella sp.; Hemicycliophora sp.; Heterodera glycines; Hoplolaimus sp.; Meloidogyne incognita; M. pini; Mononchus sp.
11.  Reproduction of Pratylenchus brachyurus on Soybean Callus Tissue: Effects of Culture Age and Observations on Anhydrobiosis 
Journal of Nematology  1986;18(4):581-582.
PMCID: PMC2618587  PMID: 19294230
anhydrobiosis; callus tissue; culturing; Glycine max; lesion nematode; Pratylenchus brachyurus; soybean
12.  Effects of Heterodera glycines and Meloidogyne incognita on Early Growth of Soybean 
Journal of Nematology  1986;18(4):444-450.
Greenhouse and field microplot studies were conducted to compare soybean shoot and root growth responses to root penetration by Heterodera glycines (Hg) and Meloidogyne incognita (Mi) individually and in combination. Soybean cultivars Centennial (resistant to Hg and Mi), Braxton (resistant to Mi, susceptible to Hg), and Coker 237 (susceptible to Hg and Mi) were selected for study. In the greenhouse, pot size and number of plants per pot had no effect on Hg or Mi penetration of Coker 237 roots; root weight was higher in the presence of either nematode species compared with the noninoculated controls. In greenhouse studies using a sand or soil medium, and in field microplot studies, each cultivar was grown with increasing initial population densities (Pi) of Hg or Mi. Interactions between Hg and Mi did not affect early plant growth or number of nematodes penetrating roots. Root penetration was the only response related to Pi. Mi penetration was higher in sand than in soil, and higher in the greenhouse than in the field, whereas Hg penetration was similar under all conditions. At 14 days after planting, more second-stage juveniles were present in roots of susceptible than in roots of resistant plants. Roots continued to lengthen in the greenhouse in the presence of either Mi or Hg regardless of host genotype, but only in the presence of Mi in microplots; otherwise, responses in field and greenhouse studies were similar and differed only in magnitude and variability.
PMCID: PMC2618586  PMID: 19294209
soybean cyst nematode; root-knot nematode; Glycine max; root penetration; root length; microplots; Heterodera glycines; Meloidogyne incognita
13.  Description of Dolichodorus cobbi n. sp. (Nematoda: Dolichodoridae) with Description of Dolichodorus cobbi n. sp. (Nematoda: Dolichodoridae) with Morphometrics and Lectotype Designation of D. heterocephalus Cobb, 1914 
Journal of Nematology  1986;18(4):556-562.
Dolichodorus cobbi n. sp. is described and illustrated from soil around roots of "woods" on the Stanley Farm, Scott County, Arkansas. This species is distinguishable from others of the genus by its short tail projection. It is most closely related to D. marylandicus but differs in having a short tail projection, longer stylet, greater body length, larger c value, and also in position of excretory pore. A limited number of Cobb's original specimens and drawings of D. heterocephalus were examined. A lectotype and paralectotype were designated to establish the taxonomic base for the genus. Cobb's original modified labeled drawing of D. heterocephalus is also included. Morphometric data on D. heterocephalus from the type locality and several other populations are given. Some variations in female tail shape, body length, and stylet length were noted.
PMCID: PMC2618585  PMID: 19294226
taxonomy; morphology; new species; Dolichodorus; woods
14.  Varietal Response and Estimates of Heritability of Resistance to Meloidogyne javanica in Carrots 
Journal of Nematology  1986;18(4):496-501.
With methods developed in this study, varietal responses to M. javanica were evaluated and heritability of resistance of two promising carrot cultivars was estimated. More egg masses were found on root systems inoculated with eggs added to the soil in three holes in 250 cm³ cups than by mixing the inoculum with soil in the cups. A resistant breeding line, CNPH 1437, was discriminated from susceptible cultivar Nova Kuroda with inoculum levels higher than 2,000 eggs per cup. Greenhouse and field results suggested that cultivars Nantes Superior and Shin Kuroda were susceptible, Kuronan was somewhat tolerant, and Brasilia and Tropical were resistant to M. javanica. Nantes Superior or Shin Kuroda yielded less in carbofuran-treated soil (3 kg a.i./ha) than Kuronan, Brasilia, and Tropical did in nontreated soil. However, incorporation of the nematicide greatly increased yields of Kuronan (32%), Brasilia (62%), and Tropical (91%). Primary root galling at the seedling stage was an adequate parameter for resistance evaluation. Estimated heritability were 0.48 ± 0.07 for primary root galling and 0.35 ± 0.08 for egg mass production in Brasilia, and 0.16 ± 0.11 for primary root galling and 0.31 ± 0.09 for egg mass production in Kuronan.
PMCID: PMC2618584  PMID: 19294218
carbofuran; Daucus carota; root-knot nematode; host response; tolerance
15.  Description of Thecavermiculatus carolynae n. sp. (Nematoda: Ataloderinae) 
Journal of Nematology  1986;18(4):548-555.
Thecavermiculatus carolynae n. sp. from the Pacific coastal area of California is described from female, male, and juvenile (J2) specimens reared on Festuca megalura Nutt. in the greenhouse. Differences between females of T. carolynae and those of its closest relative, T. gracililancea Robbins, 1978, include shorter stylet, shorter length, and lesser length of the vulval slit. Of these two species, males have been found only for T. carolynae. The habitats of the two species are vastly different: T. gracililancea has been found only in shallow clay soil near hilltops in an area subject to high summer temperatures where the soil becomes brick-like during the summer; T. carolynae has been found only in deep sandy soil of a creek bottom subject to cool summer temperatures where the soil remains moist.
PMCID: PMC2618583  PMID: 19294225
Festuca megalura; foxtail rescue; habitat; morphology; new species; scanning electron microscopy; taxonomy; Thecavermiculatus carolynae n. sp.
16.  Distribution of Ditylenchus dipsaci in Daffodil Bulbs 
Journal of Nematology  1986;18(4):586-588.
PMCID: PMC2618582  PMID: 19294232
nematode distribution; Ditylenchus dipsaci; daffodil
17.  Population Changes of Heterodera glycines and Soybean Yields Resulting from Soil Treatment with Alachlor, Fenamiphos, and Ethoprop 
Journal of Nematology  1986;18(4):458-463.
The population dynamics of Heterodera glycines as influenced by alachlor, fenamiphos, and ethoprop alone and in herbicide-nematicide combinations were studied in the field. Numbers of H. glycines juveniles and eggs were higher at midseason and harvest where nematicides were applied. Fenamiphos alone or in combination with alachlor provided better control of H. glycines and greater seed yields than treatments with ethoprop. Numbers of H. glycines eggs at harvest in 1980 were positively correlated with numbers of juveniles at planting in 1981 and negatively related to seed yield in 1981.
PMCID: PMC2618581  PMID: 19294211
chemical control; Glycine max; herbicide; soybean cyst nematode; organophosphate nematicide; pesticide interaction; population dynamics
18.  Effects of Cyanide Ion and Hypoxia on the Volumes of Second-Stage Juveniles of Meloidogyne incognita in Polyethylene Glycol Solutions 
Journal of Nematology  1986;18(4):563-570.
Changes in the volumes of second-stage juveniles of Meloidogyne incognita were monitored in aqueous solutions of polyethylene glycol supplemented with dilute balanced salts. At key points within a 48-hour cycle of fluctuating water potential, nematodes were placed under hypoxic conditions or exposed to the respiratory inhibitor, sodium cyanide, to detect any respiration-dependent process that regulates volume. Aerobic respiratory arrest at -500 kPa induced pronounced water loss, lateral and dorsoventral collapse of the body wall, and abnormal failure to shorten longitudinally. Durations of hypoxia that were innocuous in dilute solutions were lethal during 500 kPa increases and decreases in water potential; the same water potential changes under aerobic conditions had no effect on viability. Data are consistent with the hypothesis that respiration is essential to survive water potential changes.
PMCID: PMC2618580  PMID: 19294227
cyanide; hypoxia; Meloidogyne incognita; osmoregulation; oxygen; polyethylene glycol; respiratory inhibitors; volume regulation; water potential
19.  Pinewood Nematode, Bursaphelenchus xylophilus, Associated with Red Pine, Pinus resinosa, in Western Maryland 
Journal of Nematology  1986;18(4):575-580.
Red pines Pinus resinosa in Garrett and Allegany counties, Maryland, were examined during 1982-84 to determine distribution of the pinewood nematode, Bursaphelenchus xylophilus, within and among trees. Approximately 25-year-old (younger) and 47-year-old (older) trees were subdivided into the following categories: 1) trees with mostly green needles; 2) trees with mostly reddish-brown needles; 3) trees lacking needles but with bark intact; 4) trees lacking both needles and bark; and 5) trees with chlorotic, bleached-green needles. Bursaphelenchus xylophilus was found infecting 68% of younger red pines and 77% of older red pines. Nematodes were not evenly distributed in trees within any given tree decadence category or in trees of the same age. Nematodes were recovered from 20% of wood samples from trunks and primary and secondary branches in younger pines and from 15 % of older red pines. On the basis of tree decadence category, the highest incidence of infection in younger trees (31%) was in bleached-green needled trees (category 5), whereas in older trees the highest infection (25%) occurred in green needled trees (category 1). At both sites trunks were infected more often than branches.
PMCID: PMC2618579  PMID: 19294229
Bursaphelenchus xylophilus; pinewood nematode; pinewih disease; Pinus resinosa; red pine
20.  Effects of Temperature on Development of Heterodera glycines on Glycine max and Phaseolus vulgaris 
Journal of Nematology  1986;18(4):468-474.
Soybean cyst nematode resistant 'Fayette' and susceptible 'Williams 79' soybeans (Glycine max) and resistant 'WIS (RRR) 36' and susceptible 'Eagle' snap beans (Phaseolus vulgaris) were used in determining the effects of host and temperature on the development, female production, sex ratios, and host response to Heterodera glycines. Temperatures were maintained constant at 16, 20, 24, 28, and 32 C using water-filled tanks. The most rapid development and greatest female production occurred between 20 and 28 C. The equation DS = 5(10⁻⁶)x²y² - 3(10⁻⁴)x²y - 2.8(10⁻³)x² - 1.94(10⁻²)y² + 0.4288x + 1.0220y - 12.7185, where DS = developmental stage, X = time, and Y = temperature, predicted the developmental stage of the nematode and accounted for 84% of the variation. Male : female ratios did not differ within this range and were generally less than one. At all temperatures the resistant soybean produced the greatest number of necrotic responses to H. glycines infection, followed by the resistant snap bean. The susceptible soybean and snap bean produced the fewest necrotic responses.
PMCID: PMC2618578  PMID: 19294213
Glycine max; soybean; Heterodera glycines; soybean cyst nematode; hypersensitivity; modeling; Phaseolus vulgaris; snap bean; sex ratios; temperature
21.  Scanning Electron Microscopy of Second-Stage Juvenile Cephalic Morphology in Heterodera glycines Races 
Journal of Nematology  1986;18(4):475-478.
Scanning electron microscopy (SEM) was used to compare juvenile cephalic morphology of the five described races of Heterodera glycines. Races 1, 2, 3, and 4 were obtained in the United States and race 5 was obtained from Japan. Differences in the gross morphology o f labial discs; ventral, dorsal and lateral lips; amphidial apertures; and fissures on the labial disc o f some specimens were observed. There was considerable interracial and intraracial variation which precluded separation o f juveniles of H. glycines races by SEM.
PMCID: PMC2618577  PMID: 19294214
Heterodera glycines; soybean cyst nematode; morphology; races; SEM
22.  New Species of Cyst Nematode Heterodera pakistanensis (Nematoda: Heteroderidae) Attacking Wheat in Pakistan 
Journal of Nematology  1986;18(4):541-548.
Heterodera pakistanensis n. sp., described and illustrated from roots of common wheat (Triticum aestivum) from Sukkur, Sind, Pakistan, belongs to the goettingiana group. It is most closely related to H. cyperi Golden, Rau &Cobb, 1962, H. raskii Basnet & Jayaprakash, 1984, and H. mothi Khan &Husain, 1965. Second-stage juveniles (J2) can be distinguished from H. cyperi J2 by an areolated lateral field with four incisures and shorter stylet, whereas cysts are separated by a more elongated vulva slit and the conspicuous structure of the underbridge. It differs from H. raskii by having four areolated lateral lines in J2, smaller female lemon-shaped cyst, shorter fenestra length and width, conspicuous underbridge, and distinct anus with a high cuticular pattern 40-45 μm from posterior end. It also differs from H. mothi by the presence of four areolated lateral lines in J2 and absence of vulva denticles and bullae.
PMCID: PMC2618576  PMID: 19294224
taxonomy; morphology; wheat; Triticum aestivum
23.  Description of Meloidogyne christiei n. sp. (Nematoda: Meloidogynidae) from Oak with SEM and Host-Range Observations 
Journal of Nematology  1986;18(4):533-540.
Meloidogyne christiei n. sp. is described and illustrated from turkey oak (Quercus laevis) in Sanlando Park, Altamonte Springs, Florida. This new nematode species has a distinctive perineal pattern commonly with a high, squarish arch and coarse broken striae which tend to diverge at various angles, especially in and above the anal area. Female labial disc is indented, forming four points or prongs, unlike other species. Eggs are deposited inside the gall in a tubular, coiled manner. Vaginal muscles are exceptionally prominent and dense. SEM observations provided further detail of the perineal pattern and details of the head of females, males, and second-stage juveniles. Galls on the root commonly occur singly, but sometimes in small clusters, and appear as discrete nodules on the side of the root and without adjacent swelling. In general, only one female is found in each gall but occasionally two are present. In greenhouse tests, citrus, tobacco, cotton, pepper, watermelon, peanut, and tomato were not hosts. This nematode occurs throughout central Florida commonly on Q. laevis, the only known host.
PMCID: PMC2618575  PMID: 19294223
taxonomy; morphology; root-knot nematode; new species; SEM ultrastructure; Quercus laevis
24.  Influence of Alfalfa Plant Growth on the Multiplication Rates and Ceiling Population Density of Meloidogyne hapla 
Journal of Nematology  1986;18(4):505-511.
The rates of reproduction and multiplication of Meloidogyne hapla decreased as a result of self-regulatory, density-dependent processes with time and nematode population increase in the soil and roots of Medicago sativa cv. Cuf 101. Juvenile, egg, and mature female population densities increased at a maximum rate until damage to the host resulted in alfalfa yield reductions. Temporal differences in multiplication and reproduction rates of M. hapla were observed to be a function of initial population density (Pi), host damage, and root biomass, indicating increased levels of competition for a constant but limited number of feeding sites. Over time, a log linear relationship emerged between multiplication rate of M. hapla and Pi. Slopes of -0.90953 for combined eggs and juveniles and -0.71349 for mature females indicated a gradual approach to ceiling densities. Reproductive rates decreased exponentially from an initial maximal value of 200 to a relatively constant rate of 53 eggs per female.
PMCID: PMC2618574  PMID: 19294220
density dependence; intraspecific competition; reproduction; population dynamics; root-knot nematode; Medicago sativa
25.  Fluorescent and Ferritin Labelling of Cuticle Surface Carbohydrates of Caenorhabditis elegans and Panagrellus redivivus 
Journal of Nematology  1986;18(4):570-574.
Caenorhabditis elegans and Panagrellus redivivus were investigated for surface carbohydrates using fluorescent-labelled and ferritin-labelled lectins. Rhodamine-labelled Concanavalin A was specifically located in the cephalic region of both species. Rhodamine-labelled wheat germ agglutinin was located over the entire cuticle of P. redivivus but was absent on C. elegans. Rhodamine-labelled peanut agglutinin and Limax flavus agglutinin did not label nematodes of either species. Galactose and sialic acid were not detected on either species, whereas mannose-glucose residues were specifically localized in the head areas of both species. No detectable N-acetylglucosamine occurred on C. elegans, but it was evenly distributed over the cuticle surface of P. redivivus.
PMCID: PMC2618573  PMID: 19294228
Caenorhabditis elegans; cuticle; fluorescence; microscopy; lectin; Panagrellus redivivus; surface carbohydrate; transmission electron microscopy

Results 1-25 (105)