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root extracts of pangola digitgrass affect egg hatch and larval survival of meloidogyne incognita. 198319295861
reproduction of two races of meloidogyne incognita in tomato plants grown at high temperature. 198319295858
use of avermectins for the control of meloidogyne incognita on tomatoes.the efficacy of avermectins b and b for control of meloidogyne incognita on tomato was studied in pots and field plots for two seasons. avermectins were applied as granules and liquid in furrows or by low pressure drip irrigation systems, at rates ranging from 0.093 to 0.34 kg a.i./ha, as single or multiple applications. levels of control comparable to those obtained by oxamyl and aldicarb at 3.36 kg a.i./ha were achieved by the avermectin with only 1/10 the volume of chemicals applied to the en ...198319295838
interaction of vesicular-arbuscular mycorrhizal fungi and phosphorus with meloidogyne incognita on tomato.the influence of two vesicular-arbuscular mycorrhizal fungi and phosphorus (p) nutrition on penetration, development, and reproduction by meloidogyne incognita on walter tomato was studied in the greenhouse. inoculation with either gigaspora margarita or glomus mosseae 2 wk prior to nematode inoculation did not alter infection by m. incognita compared with nonmycorrhizal plants, regardless of soil p level (either 3 mug [low p] or 30 mug [high p] available p/g soil). at a given soil p level, nema ...198319295826
influence of maize rotations on the yield of soybean grown in meloidogyne incognita infested soil.a replicated field study was conducted from 1972 to 1980 involving soybeans grown in 2-, 3-, and 4-year rotations with maize in soil infested with meloidogyne incognita. monocultured soybeans were maintained as controls. cropping regimes involved root-knot nematode susceptible and resistant soybean cultivars and soybeans treated and not treated with nematicides. yields of susceptible cultivars declined with reduced length of rotation. nematicide treatment significantly increased yields of suscep ...198319295824
parasitic variability of meloidogyne incognita populations on susceptible and resistant cotton.root gall induction and egg production by the four recognized host races and two cytological races of meloidogyne incognita were compared on cotton gossypium hirsutum cvs. deltapine 16 (root-knot susceptible) and auburn 634 (highly resistant). the 12 nematode populations included in the study were from various parts of the world. no population increases occurred on the highly resistant cultivar. after 45 days, populations of host races 1 and 2 induced slight root galling on both cuhivars with on ...198319295806
validation of a model for prediction of host damage by two nematode species.plant roots were mechanically injured or subjected to nematode parasitism to test the model of host damage by two nematode species: y = m' + (l - m')c'z(p)z(p) for y </= 1.0 and y = 1.0 for y > 1.0, where m' = m + (m - m) (1 - y)/[(1 - y) + (l - y)] and c' = (z(-t) + z(-t))/2. damage functions for greenhouse-grown radish plants (cv. cherry belle) mechanically injured with small or large steel needles were used to predict growth of plants injured by both needles. growth predictions accounted for ...198319295796
effects of concomitant development on reproduction of meloidogyne incognita and rotylenchulus reniformis on sweet potato.the influence of various factors on reproduction of concomitant meloidogyne incognita (mi) and rotylenchulus reniformis (rr) on sweet potato were studied in the greenhouse. reproduction of rr was reduced by mi at all inoculum levels and experiment durations used, while mi reproduction was not inhibited. both species failed to affect each other when inoculated simultaneously onto root systems developed in separate pots from different nodes of the same plant. reproduction of each species was not s ...198319295794
population dynamics of meloidogyne incognita and rotylenchulus reniformis alone and in combination, and their effects on sweet potato.meloidogyne incognita (mi) and rotylenchulus reniformis (rr) interactions on sweet potato were studied in naturally and artificially infested field plots for 3 years. in a naturally infested field, early season counts of mi or rr were positively correlated with later counts of the same nematode, but negative correlations were found between early mi and subsequent rr, and early rr and subsequent mi counts. in field plots fumigated with methyl bromide and then infested with low levels of rr, mi, a ...198319295792
development of meloidogyne incognita inhibited by digtaria decumbens cv. pangola.population densities of the root-knot nematode, meloidogyne incognita, were lower after 90 days in soil planted to digitgrass (digitaria decumbens cv. pangola) than in soil left fallow or planted to tomato. roots of tomato seedlings interplanted with pangola digitgrass were less galled than were roots of tomato seedlings planted alone. fewer second stage larvae invaded roots of pangola digitgrass than tomato and those that entered the grass roots failed to develop beyond the late second stage.198319295772
sex differentiation in meloidogyne incognita and anatomical evidence of sex reversal.sex differentiation was studied by examining the cellular structure of gonad primordia extracted from second-stage juveniles developing under different environmental conditions. in female jnveniles, divisions of the two somatic cells of the primordium occurred in mid-sccond stage and resulted in 12 cells. two of them were differentiated as cap cells, two occupied the anterior central and eight the posterior central part of the v-shaped primordium. the two germinal cells divided at the 6-8 somati ...198219295752
genetic basis of the epidemiologic effects of resistance to meloidogyne incognita in the tomato cultivar small fry.the genetic nature of resistance and its epidemiologic effects on two meloidogyne incognita populations were assessed in the f hybrid tomato cv. small fry. the progeny of a small fry x small fry cross segregated in a 3:1 resistant:susceptible ratio, indicating the presence of a single, completely dominant resistance gene (lmir) in small fry. in a subsequent experiment, infection frequency and the rate of development of primary infection on resistant small fry x small fry segregates were compared ...198219295750
optimum initial inoculum levels for evaluation of resistance in tomato to meloidogyne spp. at two different soil temperatures.the effects of meloidogyne incognita or m. javanica at five initial inoculum levels of 20, 100, 200, 1,000, and 2,000 eggs and infective juveniles per seedling on 'floradade,' 'nemarex,' 'patriot,' and 'pi 129149-2(sib)-5' tomatoes maintained at 25 or 32.5 c were studied. the number of egg masses on roots of the susceptible cultivar floradade was similar for both species of root-knot nematodes at either 2.5 or 32.5 c soil temperatures. at 25 c, very low numbers of egg masses were produced by bot ...198219295749
estimating relative error in nematode numbers from single soil samples composed of multiple cores.spatial distributions of several species of plant-parasitic nematodes were determined in each of three fallow vegetable fields and in smaller subunits of those fields. goodness of fit to each of several theoretical distributions was tested hy means of a x(2) test. distributions for most species showed good agreement with a negative binomial model. an exception occurred with crictmemella sp., which showed a better fit to the neyman type a distribution. for nematodes distributed according to the n ...198219295747
simulated sampling strategies for nematodes distributed according to a negative binomial model.a fortran computer program was developed to simulate nematode soil sampling strategies consisting of various numbers of samples per field, with each sample consisting of various numbers of soil cores. the program assumes that the nematode species involved fit a negative binomial distribution. required input data are estimates of the mean and k values, the number of samples per field and cores per sample in the strategy to be investigated, and the number of times the simulation is to be replicate ...198219295746
effects of the temperature and duration of the initial incubation period on resistance to meloidogyne incognita in tomato. 198219295733
influence of initial population densities of meloidogyne incognita on three chile cultivars.the effects of meloidogyne incognita on the big jim, jalapeno, and new mexico no. 6 chile (capsicum annuum) cultivars were investigated in microplots for two growing seasons. all three cultivars were susceptible to m. incognita and reacted similarly to different initial populations of this nematode. severe stunting and yield suppressions occurred at all initial m. incognita densities tested ranging from 385 to 4,230 eggs and larvae/500 cm(3) soil. regression analysis of the microplot data from a ...198219295720
influence of soil temperature on meloidogyne incognita resistant and susceptible cotton, gossypium hirsutum.the degree of resistance by a cotton plant to meloidogyne incognita is affected by soil temperature, particularly in moderately resistant cultivars, the total number of nematodes in the resistant and moderately resistant rools at 35 c was equal to, or greater than, the number in susceptible roots at 20, 25, or 30 c. a shift in numbers to developing and egg-bearing forms of nematodes in the susceptible cultivar as tentperature increased indicates development was affected by temperature rather tha ...198219295718
morphological comparison of head shape and stylet morphology of second-stage juveniles of meloidogyne species.head shape and stylet morphology of second-stage juveniles of one population each of m. incognita, m. javanica, m. arenaria, and m. hapla were compared by light microscopy. excised stylets of each species were also compared by scanning electron microscopy (sem). differences in head morphology were observed only between m. hapla and the other three species. in sem, differences in stylet size, shape, and relative distance of the dorsal esophageal gland orifice to the base of the stylet were eviden ...198219295717
meloidogyne cruciani n. sp. a root-knot nematode from st. croix (u.s. virgin islands) with observations on morphology of this and two other species of the genus.meloidogyne cruciani n. sp. infecting tomato (lycopersicon esculentum mill.) in the u.s. virgin islands is described and illustrated. m. cruciani is distinguished from other species of the genus by having punctations around the anus of the female and by the second-stage juveniles possessing tri-lobed esophageal glands which are longer than most other species, with their posterier end at about 46.4% of the body length. the esophageal glands of the immature and adult females are contained in five ...198219295712
fine structure of the esophagus of males of sarisodera hydrophila (heteroderoidea).the fine structure of the esophagus, including procorpus, metacorpus, isthmus, gland lobe, and esophago-intestinal junction, is examined in males of sarisodera hydrophila. a cuticle-lined lumen extends most of the length of the esophagus, broadens to form a pump chamber in the metacorpus, and posteriorly is continuous with junctional complexes among four esophago-intestinal cells. these four cells are partially enveloped by the gland lobe which basically consists of three gland cells, one dorsal ...198219295711
the effect of arthrobotrys conoides on meloidogyne incognita population densities in corn as influenced by temperature, fungus inoculum density, and time of fungus introduction in the soil.in greenhouse experiments, the effect of arthrobotrys conoides on meloidogyne incognita population densities as affected by soil temperature, inoculum density, and green alfalfa was determined. the effect on m. incognita population densities was greater at a soil temperature of 25 c than at 18 or 32 c. nematode control by a. conoides was most effective when the fungus was introduced into the soil 2 wk prior to nematode inoculation and planting of corn. inoculum density of a. conoides was positiv ...198219295692
the relationship between soil populations of meloidogyne incognita and yield reduction of soybean in the coastal plain.in a replicated field plot experiment, the population density of meloidogyne incognita was monitored biweekly through the overwintering period (december through april) between soybean crops. the population survived as second-stage juveniles whose numbers remained stable through the winter months and did not decline until february. the yields of plots planted with a m. incognita susceptible cultivar were negatively correlated with the numbers of juveniles recovered at all preplanting sampling dat ...198219295691
development of meloidogyne incognita in stored potato tubers. 198219295688
nematicidal principles from two species of lamiaceae.aqueous extracts of ocimum sanctum and o. basilicum leaves contained compounds that killed meloidogyne incognita larvae in 160 min. thin layer and gas-liquid chromatography, and infrared spectrophotometry indicated that the essential oils eugenol and linalool were the active nematicidal compounds.198219295684
chloroplast differentiation in tomato root galls induced by the root knot nematode meloidogyne incognita.primary roots of tomato, lycopersicon esculentum cv. marglobe, were cultured aseptically on agar containing a standard nutrient formulation with or without kinetin. when secondary roots developed, cultures were inoculated with the root-knot nematode, meloidogyne incognita. following inoculation, the cultures were divided into two groups which were incubated either in total darkness or in 16-h light-8-h dark cycles. at 24 h, 1, 2, 3, and 4 wk after incubation, roots from all cultures were process ...198219295678
effects of management practices on meloidogyne incognita and snap bean yield.phenamiphos applied at 6.7 kg ai/ha through a solid set or a center pivot irrigation system with 28 mm of water effectively controlled root-knot nematodes, meloidogyne incognita, and resulted in greater snap bean growth and yields irrespective of growing season, tillage method, or cover crop system. the percentage yield increases attributed to this method of m. incognita control over nontreated controls were 45% in the spring crop, and 90% and 409% in the fall crops following winter rye and fall ...198219295676
varietal response of tomato to the interaction of salinity and meloidogyne incognita infection.response of tomato (lycopersicon esculentum) cultivars to a range of conductivity levels was tested in the presence and absence of meloidogyne incognita. the conductivity levels were produced by appropriate adjustment of a 1:1 solution of sodium chloride and calcium chloride. the growth of m. incognita resistant ('beefmaster' and 'atkinson') and susceptible ('hunts 2580' and 'ronita') tomato plants was inversely related to soil salinity between ec(e) 0 and 5 mmhos/cm. nematode inoculation of sal ...198219295675
population dynamics of meloidogyne incognita on corn grown in soil in fested with arthrobotrys conoides.microplot and greenhouse experiments were conducted to evaluate the effects of soil incorporation of the nematophagous fungus arthrobotrys conoides and green alfalfa mulch on the population dynamics of meloidogyne incognita on corn. reproduction of m. incognita and the incidence of root galling were reduced by the addition of a. conoides and/or green alfalfa in all tests. numbers of juveniles were reduced by as much as 84%, and eggs were fewest in early to mid-season soil samples from microplots ...198219295673
localization of cuticular binding sites of concanavalin a on caenorhabditis elegans and meloidogyne incognita.utilizing a concanavalin a (con a)-hemocyanin conjugate, the majority of cuticular con a binding sites were shown to be localized on the head region of caenorhabclitis elegans and meloidogyne incognita. secretions which apparently emanated from the amphids and inner labial papillae did not label.198219295672
potential of tissue culture for breeding root-knot nematode resistance into vegetables.plant protoplast technology is being investigated as a means of transferring root-knot nematode resistance factors from solanum sisymbriifolium into the susceptible s. melongena. solanum sisymbriifolium plants regenerated from callus lost resistance to meloidogyne javanica but retained resistance to m. incognita. tomato plants cloned from leaf discs of the root-knot nematode resistant 'patriot' were completely susceptible to m. incognita, while sections of stems and leaves rooted in sand in the ...198219295668
phytoalexins and their role in the resistance of plants to nematodes.phytoalexins are antibiotic compounds synthesized in an infected plant in response to infection. nematodes are capable of eliciting phytoalexins in resistant plants. resistant lima bean (phaseolus lunatus) infected by pratylenchus penetrans produces the phytoalexin coumestrol; soybean (glycine max) infected by meloidogyne incognita produces glyceollin; cotton (gossypium hirsuturn) infected by m. incognita produces terpenoid aldehydes.198219295667
effects of cyanide ion and hypoxia on the volumes of second-stage juveniles of meloidogyne incognita in polyethylene glycol solutions.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 dors ...198619294227
retention of resistance to meloidogyne incognita in lycopersicon genotypes at high soil temperature.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 ...198619294217
effect of meloidogyne incognita and importance of the inoculum on the yield of eggplant.the relationship between population densities of race 1 of meloidogyne incognita and yield of eggplant was studied. microplots were infested with finely chopped nematode-infected pepper roots to give population densities of 0, 0.062, 0.125, 0.25, 0.50, 1, 2, 4, 8, 16, 32, 64, and 128 eggs and juveniles/cm(3) soil. both plant growth and yield were suppressed by the nematode. a tolerance limit of 0.054 eggs and juveniles/cm(3) soil and a minimum relative yield of 0.05 at four or more eggs and juve ...198619294216
a comparison of techniques useful for preparing nematodes for scanning electron microscopy.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% ...198619294215
soybean yield as related to rates of 1,3-dichloropropene applied at planting for management of root-knot disease.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 infestation ...198619294212
soybean and maize cropping models for the management of meloidogyne incognita in the coastal plain.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 cm(3) soil for susceptible soybean, resistant soybean, and maize, respectively. yearly changes in the population density of juveniles due to rotati ...198619294210
effects of heterodera glycines and meloidogyne incognita on early growth of soybean.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; r ...198619294209
effects of interactions among heterodera glycines, meloidogyne incognita, and host genotype on soybean yield and nematode population densities.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 ...198619294208
penetration and postinfection development of meloidogyne incognita on cotton as affected by glomus intraradices and phosphorus.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 ino ...198619294207
comparison of development, reproduction, and aggressiveness of meloidogyne incognita races 3 and 4 on cotton. 198619294201
management of root-knot nematodes by phenamiphos applied through an irrigation simulator with various amounts of water.phenamiphos (6.7 kg a.i./ha) was applied via an irrigation simulator to squash at planting (ap) and 2 weeks after planting (pp), and to corn ap and 1 week pp to manage root-knot nematodes (meloidogyne incognita). the nematicide was applied with 0.25, 0.64, 1.27, and 1.91 cm surface water/ ha to a lakeland sand in which the soil moisture was at or near field capacity. based on efficacy and crop response, no additional benefits resulted when phenamiphos was applied in volumes of water greater than ...198619294192
meloidogyne incognita resistance characteristics in tomato genotypes developed for processing.nine resistant processing tomato (lycopersicon esculentum) cultivars and advanced lines were compared with four susceptible cultivars in 1,3-dichloropropene-fumigated and nontreated plots on meloidogyne incognita-infested sites over 3 years. yield of all resistant genotypes grown in nontreated and nematicide-treated plots did not differ and was greater than yield of susceptible genotypes. m. incognita initial soil population densities caused 39.3-56.5% significant (p = 0.05) yield suppressions o ...198619294190
effects of environments, meloidogyne incognita inoculum levels, and glycine max genotype on root-knot nematode-soybean interactions in field microplots.five soybean cultivars (braxton, gordon, jeff, bragg, and wright) resistant to meloidogyne incognita (mi) and three susceptible cultivars (coker 156, gasoy 17, and coker 237) were grown at two locations for four seasons in microplots with increasing initial soil population densities (pi) of mi. the resistant cultivars and coker 156 yielded better than gasoy 17 and coker 237 at all pi. yield response was dependent on environmental conditions and at one location was stimulated on braxton, gordon, ...198619294188
effects of soil type on the damage potential of meloidogyne incognita on soybean.effects of soil type on the reproduction and damage potential of meloidogyne incognita on soybean, glycine max (l.) merr., were determined at five locations in north carolina, including one site where plots with six soil types were established. m. incognita reproduced readily on a susceptible soybean cultivar in most soil types, with somewhat limited reproduction in muck soils. the relationship between initial population densities and yield varied among soil types and nematode populations. yield ...198619294187
relative virulence of meloidogyne incognita host races on soybean.sensitivity and host efficiency of susceptible ('lee 68', 'coker 156') and resistant ('bragg', 'centennial', 'forrest', 'lee 74') soybean (glycine max (l.) merr.) cultivars for races of meloidogyne incognita (mi) were determined in greenhouse experiments. eight mi populations collected from the southeastern united states were utilized. all mi races reproduced readily on lee 68 and lee 74 and moderately on forrest and bragg. coker 156 exhibited resistance to races 1 and 2, and some race 3 populat ...198619294186
effects of temperature, plant age, soil texture, and meloidogyne incognita on early growth of soybean.a digitizer-microcomputer combination was utilized to determine soybean seedling response to population densities of m. incognita (mi) under varied environmental conditions. plant age, temperature, soil texture, and initial mi inoculum (pi) influenced the pattern of shoot and root growth. effects of mi on plant top growth were evident on plants inoculated 2 days after seeding, but generally were not noticeable on those receiving mi after 4, 6, or 8 days (observations limited to 6 days after inoc ...198619294185
cuticular collagenous proteins of second-stage juveniles and adult females of meloidogyne incognita: isolation and partial characterization.cuticles isolated from second-stage juveniles and adult females of meloidogyne incognita were purified by treatment with 1% sodium dodecyl sulfate (sds). the juvenile cuticle was composed of three zones differing in their solubility in beta-mercaptoethanol (bme). proteins in the cortical and median zones were partially soluble in bme, whereas the basal zone was the least soluble. the bme-soluble proteins from the juvenile cuticle were separated into 12 bands by sds-polyacrylamide gel electrophor ...198619294181
interaction of endomycorrhizal fungi, superphosphate, and meloidogyne incognita on cotton in microplot and field studies.microplot and field experiments were conducted to determine the effects of two vesicular-arbuscular mycorrhizal (vam) fungi, glomus intraradices (gi) and gigaspora margarita (gm), and dicalcium phosphate (p) on meloidogyne incognita (mi) reproduction and seed cotton yield of the mi-susceptible cotton cultivar, stoneville 213. in 1983 population densities of mi juveniles were significantly lower 60 and 90 days after planting in microplots receiving gi. mycorrhizal fungi reduced the severity of yi ...198619294168
distribution of field corn roots and parasitic nematodes in subsoiled and nonsubsoiled soil.a field trial was conducted for 2 years in an arredondo fine sand containing a tillage pan at 15-20 cm deep to determine the influence of subsoiling on the distribution of corn roots and plant-parasitic nematodes. soil samples were taken at various depths and row positions at 30, 60, and 90 days after planting in field corn subsoiled under the row with two chisels and in non-subsoiled corn. at 30 and 60 days, in-row nematode population densities to 60 cm deep were not affected by subsoiling comp ...198619294167
interrelationships of meloidogyne arenaria and m. incognita on tolerant soybean.reproduction of meloidogyne arenaria race 2 was excellent on centennial, govan, and kirby soybeans, the latter two of which have tolerance to this species. the m. incognita race 1 isolate reproduced poorly on centennial, especially at the higher of two temperature regimes. numbers of galls and egg masses of m. arenaria plus m. incognita in simultaneous equivalent infestations on centennial did not differ from sequential infestations in which m. arenaria was added first and m. incognita was added ...198619294149
genotypic differentiation of meloidogyne populations by detection of restriction fragment length difference in total dna.detection of ecori restriction fragment length differences in repetitive dna sequences permitted the rapid diagnosis, by genotype, of randomly selected populations of meloidogyne incognita, races 1, 2, 3, and 4; m. javanica; m. arenaria, races 1 and 2; and m. hapla, races a and b.198619294145
influence of meloidogyne incognita on resistant and susceptible sweet potato cultivars.effects of several population densities ofmeloidogyne incognita on the sweet potato cultivars centennial (susceptible) and jasper (moderately resistant) were studied. field plots were infested with initial levels (pi) of 0, 10, 100, 1,000, 5,000, and 10,000 eggs and juveniles/500 cm(3) soil in 1980 and 0, 100, 1,000, 2,000, 3,000, 4,000, and 5,000 in 1981. m. incognita population development trends were similar on both cultivars; however, at high pi, more eggs and juveniles were recovered from c ...198619294141
isolation of subcellular granules from second-stage juveniles of meloidogyne incognita.subcellular granules from the second-stage (preparasitic) juveniles of root-knot nematode meloidogyne incognita were isolated by isopycnic centrifugation on percoll. the granules had an apparent density of 1.13 g/cm(3). the relative specific activity of acid phosphatase in the granule extract was 8.4. acid phosphatase activity was also detected histochemically in the subventral gland granules. electron microscopy and malate dehydrogenase activity indicated that contamination of granules by mitoc ...198519294128
behavior of tethered meloidogyne incognita.the tethered-nematode technique was adapted for use with second-stage juveniles of meloidogyne incognita. the data demonstrate that m. incognita exhibits the same patterns of behavior as adults of the free-living nematode, caenorhabditis elegans. the principal differences are that m. incognita is slower and less regular in its behavior than c. elegans. the frequency of normal waves is about 0.2 hz; that of reversal waves is about 0.06 hz. reversal bouts last about 1 minute. in response to a chan ...198519294124
interactions between six warm-season legumes and three species of root-knot nematodes. 198519294109
control of root-knot nematodes on tomato by the endoparasitic fungus meria coniospora.the endoparasitic nematophagous fungus meria coniospora reduced root-knot nematode galling on tomatoes in greenhouse pot trials. the fungus was introduced to pots by addition of conidia at several inoculum levels directly to the soil or addition of nematodes infected with m. coniospora to the soil; both methods reduced root galling by root-knot nematodes. these studies represent a part of a recently initiated effort to evaluate the potential of endoparasitic nematophagous fungi for biocontrol of ...198519294101
nematode control related to fusarium wilt in soybean and root rot and zinc deficiency in corn.nematode and disease problems of irrigated, double-cropped soybean and corn, and zinc deficiency of corn were investigated. ethylene dibromide, phenamiphos, and aldicarb were equally effective for controlling nematodes and increasing yields of corn planted minimum-till and soybean planted in a moldboard plow prepared seedbed. the residual effects on yields of nematicides applied to the preceeding crop occurred during 3 years for soybean and 1 year for corn. fusarium wilt symptoms of soybean that ...198519294099
dynamics of winter survival of eggs and juveniles of meloidogyne incognita and m. arenaria.winter survival dynamics of meloidogyne incognita and m. arenaria were studied at nine sites in texas for 2 years. population survival from october until april was variable among sites, ranging from 0.1% to 33%. a negative correlation (r = -0.86, p = 0.01) was observed between initial population, densities in october and survival percentage until the following april. total population (eggs + j2) and population of eggs declined continuously during the survival period. populations of juveniles (j2 ...198519294090
overestimation of yield loss of tobacco caused by the aggregated spatial pattern of meloidogyne incognita.overestimation of yield loss caused by meloidogyne incognita on tobacco was calculated as a function of the statistical frequency distribution of sample counts. sampling frequency distributions were described by a negative binomial model, with parameter k, and the resulting probability generating function was used to calculate discrete damage probabilities. negative binomial damage predictions were compared to mean-density estimates of damage. predictions based on mean density alone overestimate ...198519294089
root penetration by meloidogyne incognita juveniles infected with bacillus penetrans.bacillus penetrans inhibited penetration by meloidogyne incognita second-stage juveniles (j2) into tomato roots in the laboratory and greenhouse. spores from this florida population of b. penetrans attached to j2 of m. javanica, m. incognita, and m. arenaria. a greater proportion of j2 of m. javanica were infected than were j2 of either m. incognita or m. arenaria, and a greater number of spores attached to m. incognita than to m. arenaria.198519294069
density-dependent nematode seasonal multiplication rates and overwinter survivorship: a critical point model.nematode multiplication rates pf/pi and overwinter survivorship (pi2/pfl) for meloidogyne incognita were both adequately described by negative exponential models, indicating density dependence in each case. density dependence of the multiplication rates is mediated by resource limitation and host damage; in survivorship rates it may be mediated by limitation of stored reserves or prevalence of antagonists. parameters of multiplication rate models were crop specific and varied with host status an ...198519294065
spatial pattern analysis of plant-parasitic nematodes.spatial patterns of meloidogyne incognita, tylenchorhynchus claytoni, helicotylenchus dihystera, and criconemella ornata were analyzed using hill's two-term local quadrat variance method (ttlqv), spectral analysis, and spatial correlation. data were collected according to a systematic grid sampling plan from seven tobacco fields in north carolina. different estimates of nematode cluster size were obtained through ttlqv and spectral analysis. no relationship was observed between either estimate a ...198519294064
population densities of meloidogyne incognita and yield of capsicum annuum.two microplot experiments in 1981 and 1983 provided information on the effect of different population densities of meloidogyne incognita race 1 and yield of sweet pepper. microplots were square concrete pipes (30 x 30 cm and 50 cm long) filled with 40 liters of soil infested with 0, 0.062, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512 eggs and juveniles/cm(3) soil. tolerance limits of 2.2 and 0.165 eggs and juveniles/cm(3) soil and minimum yields of 58% and 20% of the controls were ...198519294056
effect of tillage system and irrigation on population densities of plant nematodes in field corn.soil populations of plant-parasitic nematodes were monitored bimonthly for 18 months in irrigated and nonirrigated corn plantings using four production systems: conventional and minimum tillage with crop residue returned and minimum tillage with 60% or 90% of previous corn crop residue removed. populations of meloidogyne incognita, scutellonema brachyurum, pratylenchus scribneri, and paratrichodorus christiei varied among the tillage, nematicide, and irrigation treatments. meloidogyne incognita ...198519294053
variability in reproduction of four races of meloidogyne incognita on two cultivars of soybean.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 o ...198419294039
pathogenicity and reproduction of hoplolaimus columbus and meloidogyne incognita on 'davis' soybean.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 r ...198419294036
nematostatic activity of oxamyl and n,n-dimethyl-1-cyanoformamide (dmcf) on meloidogyne incognita juveniles.the nematostatic activity of oxamyl, methyl-n',n'-dimethy]-n-hydroxy-l-thiooxamimidate (oxamyl-oxime) and n,n-dimethyl-l-cyanoformamide (dmcf) was studied by immersing 10 meloidogyne incognita second-stage juveniles into aqueous solutions of various concentrations of each chemical. at concentrations of 500 to 8,000 mug/ml, oxamyl quickly immobilized immersed juveniles. in all other concentrations studied (down to 4 mug/ml), oxamyl stopped or reduced movement of juveniles within 24 hours. dmcf al ...198419294031
crop rotation and races of meloidogyne incognita in cotton root-knot management.the influence o f various crop rotations and nematode inoculum levels on subsequent population densities of meloidogyne incognita races 1 and 3 were studied in microplots. ten different 3-year sequences o f cotton, corn, peanut, or soybean, all with cotton as the 3rd-year crop, were grown in microplots infested with each race. cotton monoculture, two seasons o f corn, or cotton followed by corn resulted in high race 3 population densities and severe root galling on cotton the 3rd year. peanut fo ...198419294030
potential of crops uncommon to alabama for management of root-knot and soybean cyst nematodes.vigna unguiculata, cassia fasiculata, and sesamum indicum did not support meloidogyne arenaria, m. incognita, or heterodera glycines race 4 in greenhouse studies with soils from peanut and soybean fields. fagopyron eseulentum, cyamopsis tetragonoloba, and cucurbita pepo were hosts to the two meloidogyne spp. but were nonhosts to h. glycines. meloidogyne arenaria and m. incognita galled but reproduced poorly in the roots of three types of amaranthus cruentus, and low densities of these two meloid ...198819290317
bahiagrass for the management of meloidogyne arenaria in peanut.bahiagrass (paspalum notatum) cultivars argentine, pensacola, and tifton-9 were non-hosts for meloidogyne arenaria, m. incognita, and heterodera glycines in a greenhouse experiment using field soil infested with these nematodes. the effect of pensacola bahiagrass in rotation with peanut (arachis hypogaea) on m. arenaria was studied in 1986 and 1987 in a field at the wiregrass substation near headland, alabama. each year soil densities of second-stage juveniles of m. arenaria, determined near pea ...198819290315
tillage and multiple cropping systems and population dynamics of phytoparasitic nematodes.the effect of two cropping and tillage systems on the population dynamics of four nematode species was evaluated on a loamy sand. hairy vetch succeeded by corn or grain sorghum was seeded in split plots randomized within whole plots of no-tillage versus conventional tillage over four growing seasons (1980-83). the vetch-corn cropping system increased the density of meloidogyne incognita 2.9 x more than the vetch-grain sorghum cropping system. in contrast, the vetch-grain sorghum cropping system ...198819290311
response of cotton to infection by hoplolaimus columbus.three field experiments were established in 1987 to determine the reaction of five cotton cultivars to infection by hoplolaimus columbus and the efficacy of selected nematicides against this nematode. at two sites in calhoun county, south carolina, early season plant growth and subsequent yields were greater in plots treated with aldicarb, fenamiphos, and 1,3-dichloropropene. hoplolaimus columbus suppressed yields approximately 10% at site 1 and 25% at site 2; however, greater yield suppression ...198819290310
resistance in commercial soybean cultivars to six races of heterodera glycines and to meloidogyne incognita.soybean cultivars grown in pots in the greenhouse were tested for resistance by inoculation with meloidogyne incognita or one of six races of heterodera glycines. selected cultivars were tested against each nematode isolate. the numbers of cultivars tested against each h. glycines race and the numbers resistant and (or) moderately resistant were as follows: race 2 - 114 tested, 1 resistant and 9 moderately resistant; race 3 - 170 tested, 56 resistant and 17 moderately resistant; race 4 - 89 test ...198819290307
host suitability of grain sorghum cultivars to meloidogyne spp.grain sorghum cultivars (funk g-499gbr, funk g-611, funk g-522a, funk g-522dr, coker 7723, coker 7675, coker 7623, pioneer b815, pioneer 8222, pioneer 8272) were evaluated in the greenhouse for resistance to populations of meloidogyne incognita race 3, m. arenaria race 2, and m. javanica from south carolina, and m. arenaria race 1 from georgia. all the sorghum cultivars were poor hosts or nonhosts of meloidogyne spp. with fewer than 1 or 2 egg masses per root system in all cultivar x nematode co ...198819290305
transport of the nematicide oxamyl in roots transformed with agrobacterium rhizogenes.infection of roots transformed with agrobacterium rhizogenes by meloidogyne incognita and heterodera schachtii second-stage juveniles was established in bicompartmental petri dishes. one compartment contained the murashige and skoog agar medium and the nematicide oxamyl, and the other compartment contained water agar. transformed roots of carrot, tomato, alfalfa, cowpea, rape, and sugarbeet were placed in the nutrient compartment and grew over the barrier that divided the petri dishes and into t ...198819290298
effects of several phytoparasitic nematodes on the growth of basil, ocimum basilicum.greenhouse experiments were conducted in 15-cm-d pots of steamed myakka fine sand to determine the host status and tolerance of common basil (ocimum basilicum) to several important phytoparasitic nematodes in florida. populations of meloidogyne incognita, belonolaimus longicaudatus, and pratylenchus scribneri increased and caused significant suppression of foliage and root growth during a 10-month period. the population of paratrichodorus christiei increased and caused a significant reduction in ...198819290296
nematode population densities and yield of sweet potato and onion as affected by nematicides and time of application.nematode population densities and yield of sweet potato and onion as affected by nematicides and time of application were determined in a 3-year test. population densities of meloidogyne incognita race 1 in untreated plots of sweet potato increased each year, but helicotylenchus dihystera and criconemella ornata did not. ethoprop (6.8 kg a.i./ha) incorporated broadcast in the top 15-cm soil layer each spring before planting sweet potato reduced population densities of nematodes in the soil and i ...198819290295
screening of a granular chelate of metham-zinc for nematicidal activity using citrus and root-knot nematodes.a granular formulation of a chelate of metham-zinc (cmz) which liberates the biocidal methyl isothiocyanate was tested for nematicidal activity on tylenchulus semipenetrans in a jar soil screening and on meloidogyne javanica (greenhouse test) and m. incognita (field test) infecting tomato. comparisons were made with 1,3-d in the jar and pot experiments. the cmz caused only 3.9% mortality of citrus nematode juveniles at 1.0 mug a.i./g soil, but 95.4% mortality at 10.0 mug a.i./g and 100.0% at 100 ...198819290294
nematode response to cool season annual graminaceous species and cultivars.the response of 29 rye, oat, triticale, and wheat cultivars to selected nematode species was determined in the greenhouse. variability in nematode root galling and final nematode population densities in root and soil in response to cool season annual graminaceous crops occurred for spiral (helicotylenchus dihystera), stubby root (paratrichodorus minor), and root-knot (meloidogyne incognita) nematodes. although none of the graminaceous crops supported m. incognita at levels as high as the suscept ...198719290289
comparative resistance of selected acala 1517 cotton cultivars to meloidogyne incognita race 3.little information is available regarding the levels of meloidogyne incognita race 3 resistance in acala 1517 cotton cultivars compared with cultivars grown outside the southwestern united states. levels of m. incognita egg production were compared among commercial acala cultivars 1517-e2, 1517-sr1, 1517-75, 1517-77br, and sj-5, resistant and susceptible standards auburn 634 and m-8 and breeding lines acala 5701-w and n6072 grown for 45 days in the greenhouse. the acala 1517 cultivars all perfor ...198719290288
effect of combining soil solarization with certain nematicides on target and nontarget organisms and plant growth.field experiments compared pesticidal and plant growth effects of soil solarization, alone and in combination, with overall applications of several nematicides. nematodes, including meloidogyne incognita j2, that were targeted for control were significantly reduced (p < 0.05) by solarization, 1,3-dichloropropene (44 and 132 liter/ha), ethoprop (13.5 kg/ha), metham sodium (64 liter/ha), formaldehyde (111 liter/ha), and by solarization-nematicide combinations. control of pythium ultimum also was o ...198719290287
effects of aldicarb on nematodes, early season insect pests, and yield of soybean.the effects of aldicarb on soybean cyst (heterodera glycines) and root-knot (meloidogyne incognita and m. arenaria) nematode populations, early season insect pests and soybean (glycine max) yield were evaluated in five field experiments in northern and southern alabama. aldicarb significantly (p = 0.05) reduced nematode populations in only two cases: m. arenaria in centennial soybean in the wiregrass site and m. incognita in bedford soybean in a tennessee valley site. no significant difference ( ...198719290282
effects of nematicides and herbicides alone or combined on meloidogyne incognita egg hatch and development.the effects of nematicides carbofuran (c) and fenamiphos (f) and herbicides metribuzin (m) and trifluralin (t), alone and in combination, on hatching, penetration, development, and reproduction of meloidogyne incognita race 3 were determined under laboratory conditions. to study hatching, entire egg masses were exposed to nematicides (6 mug/ml), herbicides (0.5 mug/ml), and their combinations over a period of 16 days; the hatched juveniles were extracted and counted every 48 hours. second-stage ...198719290279
soybean response to a planting-time application of ethylene dibromide in a soil infested with meloidogyne incognita, m. arenaria, and heterodera glycines.a field study was conducted to evaluate one susceptible and six nematode-resistant soybean cultivars for their effects on seed yield, nematode populations, and response to a fumigant nematicide, ethylene dibromide. the soil was a sandy loam, and the field was infested with a mixture of meloidogyne incognita, m. arenaria, and heterodera glycines. soybean cultivars significantly affected yield and juvenile numbers of meloidogyne spp. but did not affect the h. glycinesjuvenile population. fumigatio ...198719290278
response of cowpea breeding lines and cultivars to meloidogyne incognita and m. arenaria.twenty-four cowpea breeding lines and four cultivars were tested for resistance to meloidogyne incognita in the greenhouse. gall and egg mass ratings indicated a range of responses from susceptible to highly resistant. five breeding lines - vs84-2, vs84-8, vs84-12, vs84-14, and vs84-22 - and the cultivar erectset had gall and egg mass ratings comparable to the m. incognita-resistant cultivar mississippi silver. all of these were also resistant to m. arenaria. significantly fewer m. incognita juv ...198719290274
evaluation of soybean cultivars for production in meloidogyne incognita-infested soil.significant (p < 0.05) differences among galling and yields of 41 soybean cultivars and breeding lines were found when they were produced at a site infested with meloidogyne incognita during 3 years of investigation. over a period of 6 years of testing, 13 cultivars were identified as having a suitably low susceptibility to warrant their production in m. incognita infested soil.198719290271
geographical distributions of rotylenchulus reniformis, meloidogyne incognita, and tylenchulus semipenetrans in the lower rio grande valley as related to soil texture and land use.a survey was conducted over a 22-year period to evaluate the influence of soil texture and land use on the geographical distributions of rotylenchulus reniformis, meloidogyne incognita, and tylenchulus semipenetrans in the lower rio grande valley. the distributions of r. reniformis and m. incognita were related to soil texture, whereas t. semipenetrans occurred wherever host plants were present regardless of soil texture. the incidence of m. incognita was greatest in elevated sandy loams and mod ...198719290268
host suitability of commercial corn hybrids to meloidogyne arenaria and m. incognita.the host suitability of 64 commercial corn hybrids for a meloidogyne arenaria race 2 population and a m. incognita race 4 population was determined in greenhouse experiments. 'northrup king 508' and 'pioneer brand 3147' maintained m. arenaria below and at the initial population level, respectively, indicating that these hybrids are relatively poor hosts for this species. rf values (final egg number/initial egg number) of the hybrids for m. arenaria ranged from 0.8 for northrup king 508 to 42.3 f ...198719290266
characterization of carbohydrates on the surface of second-stage juveniles of meloidogyne spp.fluorescent conjugates of the lectins soybean agglutinin (sba), concanavalin a (con a), wheat germ agglutinin (wga), lotus tetragonolobus agglutinin (lot), and limulus polyphemus agglutinin (lpa) bound primarily to amphidial openings and amphidial secretions of viable, preinfective second-stage juveniles (j2) of meloidogyne incognita races 1 and 3 (mil, mi3) and m. javanica (mj). no substantial difference in fluorescent lectin binding was observed among the populations examined. binding of only ...198819290262
extremely sensitive thermotaxis of the nematode meloidogyne incognita.eggs of the root-knot nematode meloidogyne incognita were acclimated to 23 c. newly hatched second-stage juveniles migrated toward higher temperatures when placed in shallow thermal gradients averaging 23 c. the threshold gradient for this response was below 0.001 c/cm, with a best estimate of 4 x 10 c/cm. calculations of physical limitations on thermotaxis indicate that this sensitivity is well within the limits of what is physically possible.198819290261
growth and energy demand of meloidogyne incognita on susceptible and resistant vitis vinifera cultivars.food (energy) consumption rates ofmeloidogyne incognita were calculated on vitis vinifera cv. french colombard (highly susceptible) and cv. thompson seedless (moderately resistant). one-month-old grape seedlings in styrofoam cups were inoculated with 2,000 or 8,000 m. incognita second-stage juveniles (j2) and maintained at 17.5 degree days (dd - base 10 c)/day until maximum adult female growth and (or) the end of oviposition. at 70 dd intervals, nematode fresh biomass was calculated on the basis ...198819290253
effect of meloidogyne incognita and m. javanica on leaf water potential and water use of tobacco.greenhouse lysimeter and field microplot tests were conducted to evaluate the effects of meloidogyne incognita and m. javanica on plant water relations and growth performance of nc 2326 flue-cured tobacco. in the greenhouse, afternoon leaf water potential values at 8-11 weeks after transplanting were lower by as much as 0.22 mpa in plants infected with either nematode than in the control plants. from 11 to 22 weeks, leaf water potential values were similar in all treatments. over the course of t ...198819290249
relationship between egg viability and population densities of meloidogyne incognita on cotton.cotton seedlings were inoculated with a range of initial populations (pi) of meloidogyne incognita in greenhouse experiments to test the relationship between nematode population densities and egg viability. in two of three experiments, a significant (p < 0.05) negative linear relationship was detected between percentage of hatch of first generation eggs and log pi. a similar relationship between hatch and root-gall index was observed. in two experiments numbers of eggs judged to be nonviable bas ...198819290248
meloidogyne incognita and tomato response to thiamine, ascorbic acid, l-arginine, and l-glutamic acid.the influence of solutions of ascorbic acid, thiamine, l-arginine, and l-gtutamic acid on egg hatch, juvenile survival, and development and reproduction of meloidogyne incognita in susceptible and resistant tomatoes was studied. maximum inhibition of egg hatch occurred at 2,000, 4,000, and 2,000 ppm for ascorbic acid, l-arginine, and l-glutamic acid, respectively. larval survival was significantly reduced by concentrations of 2,000 ppm ascorbic acid and 1,000 ppm of l-arginine. maximum inhibitio ...198819290237
histology of the interactions of paecilomyces lilacinus with meloidogyne incognita on tomato.excised tomato roots were examined histologically for interactions of the fungus paecilomyces lilacinus and meloidogyne incognita race 1. root galling and giant-cell formation were absent in tomato roots inoculated with nematode eggs infected with p. lilacinus. few to no galls and no giant-cell formation were found in roots dipped in a spore suspension of p. lilacinus and inoculated with m. incognita. numerous large galls and giant cells were present in roots inoculated only with m. incognita. p ...198819290224
behavioral responses of meloidogyne incognita to small temperature changes.small, rapid temperature changes were generated by incandescent radiation, and behavioral responses of meloidogyne incognita juveniles were recorded with high time resolution by computer tracking. temperature changes away from the preferred temperature resulted in decreases in the rate of movement and increases in the rate of change of direction, whether the changes were toward warmer or cooler temperatures. these behavioral changes lasted about 30 seconds. temperature changes toward the preferr ...198819290222
lectin binding sites on the amphidial exudates of meloidogyne.lectin binding sites on the surface of meloidogyne incognita races 1, 2, 3, and 4; m. javanica; m. arenaria races 1 and 2; and m. hapla races a and b were determined with lectins conjugated to fluorescein isothiocyanate or colloidal gold. the amphidial exudate, which was demonstrated histochemically to contain carbohydrate, was the principal binding site. some lectins also bound to the external cuticular surface. species and race specific binding patterns were observed for both amphidial and cut ...198819290216
ultrastructural cytochemistry of secretory granules of esophageal glands of meloidogyne incognita.ultrastructural cytochemical tests for several enzymes, proteins, carbohydrates, and nucleic acids were conducted on secretory granules o pound dorsal and subventral esophageal glands of preparasitic second-stage juveniles and the dorsal gland of adult females of meloidogyne incognita. secretory granules in the subventral glands of juveniles stained positive for acid phosphatase. peroxidase, dnase, rnase, cellulase, and nucleic acids were not detected in these granules. secretory granules in the ...198819290195
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