Showing papers on "Meloidogyne incognita published in 1987"

Biological Control of Meloidogyne incognita by Paecilomyces lilacinus and Pasteuria penetrans.

Abstract: The root-knot nematode Meloidogyne incognita was controlled more effectively and yields of host plants were greater when Paecilomyces lilacinus and Pasteuria penetrans were applied together in field microplots than when either was applied alone. Yields of winter vetch from microplots inoculated with the nematode and with both organisms were not statistically different from yields from uninoculated control plots. Key words: Bacillus penetrans, bacterial spore parasite, biocontrol, fungus parasite, southern root-knot nematode, Meloidogyne incognita, Paecilomyces lilacinus, Pasteuria penetrans.

Geographical Distributions of Rotylenchulus reniformis, Meloidogyne incognita, and Tylenchulus semipenetrans in the Lower Rio Grande Valley as Related to Soil Texture and Land Use.

Abstract: 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 moderately well-drained silts of modern flood terraces of the Rio Grande river. Rotylenchulus reniformis occurred predominantly in clay silts and clays of ancient flood terraces. Clay loams and sandy clay loams of the central, irrigated portion of the lower Rio Grande valley appeared favorable for M. incognita and R. reniformis. Differences between the geographical distributions of these two species could not be attributed to host crops. Key words: citrus, geographical distribution, Meloidogyne incognita, population ecology, Rotylenchulus reniformis, survey, TylenchuIus semipenetrans.

Effect of Meloidogyne incognita on Plant Nutrient Concentration and Its Influence on the Physiology of Beans.

Abstract: Phaseolus vulgaris plants, 3, 8, 11, and 13 days old, were inoculated with 0, 2,000, 4,000, or 8,000 second-stage Meloidogyne incognita larvae and maintained under controlled conditions. The photosynthetic rate and the shoot and root concentration of K, Ca, Mn, Fe, Cu, and Zn were determined by destructive assay at 1-27-day intervals and by nondestructive assay of leaves, stems, and roots at 27 or 28 days after inoculation. In the destructive assay, the concentration of the elements in the plant tissues did not change until 1 week after inoculation. Thereafter, the trend was mostly decreasing for shoot K and Fe and increasing in the root, whereas Ca had the opposite trend in the shoots. Manganese, Cu, and Fe showed variable trends. Generally, the concentration of K and Mn increased, whereas Ca and Fe decreased, with duration of infection in all treatments. Zinc and Cu decreased in the highest nematode treatments. The overall elemental content generally decreased with level of infection from 1 week after inoculation. Photosynthetic rate based on shoot K concentration significantly decreased with level of infection. In most of the nondestructive assays, the concentrations of shoot K, Zn, and Mn decreased, whereas Ca increased with increasing nematode treatment. One of the first effects of the nematode on host physiology appears to be a change in concentration of nutrient elements in the host plant.

The Influence of Planting Date of Carrot On Meloidogyne Incognita Reproduction and Injury To Roots

Abstract: Carrot cv. Emperator was direct seeded into Meloidogyne incognita infested sandy loam field plots at Tustin, southern California, on five dates each two weeks apart starting in mid-October. Harvest dates were similarly staggered in the following spring. Significant differences in plant weights at harvest were not found. Percentages of tap roots rendered unmarketable due to galling and forking symptoms were 50.3, 30.8, 19.3, 8.9 and 11.2 respectively on the five plantings. Root injury was related to the level of infection in early season, as influenced by soil temperatures that fluctuated near the M. incognita activity threshold of 18°C. Accumulated temperature, particularly from mid-season onward, determined final nematode numbers, which were significantly (P = 0.05) more on the fourth and fifth plantings. The importance of changing planting dates of winter vegetables for suppressing root-knot nematodes was demonstrated.

Effective use of marine algal products in the management of plant-parasitic nematodes.

Abstract: Algal extracts were ineffective against Meloidogyne spp., Panagrellus redivivus, and Neoaplectana carpocapsae at 1.0% aqueous concentrations, with the exception of Spatoglossum schroederi. S. schroederi killed Meloidogyne incognita, M. javanica, M. acrita, and Hoplolaimus galeatus at concentrations of 1.0, 0.75, and 0.50%. Extracts from S. schroederi at a concentration of 1.0% were ineffective against Hirschmanniella caudacrena and Belonolaimus longicaudatus. Spatoglossum schroederi, Botryocladia occidentalis, and Bryothamnion triquestrum when used as soil amendments at 0.5-1.0% concentrations (by weight) produced significant reduction of root gall development in tomato plants infected with M. incognita. Tomato plant growth was significantly improved by these algae, as well as by Caulerpa prolifera. Soil amendments of S. schroederi at concentrations of 0.5 and 1.0% significantly reduced root galling of tomato infected with M. incognita, M. arenaria, and M. javanica. Tomatoes grown in algal-soil mixture produced significantly heavier shoots and roots than plants raised in autoclaved soil. No significant differences in root-knot indices, nor in fresh and dry weights of tomato, were noted between the two concentrations of algal-soil mixture.

Sterol Composition and Ecdysteroid Content of Eggs of the Root-knot Nematodes Meloidogyne incognita and M. arenaria.

Abstract: Free and esterified sterols of eggs of the root-knot nematodes Meloidogyne incognita races 2 and 3 and M. arenaria race 1 were isolated and identified by gas-liquid chromatography-mass spectrometry. The major sterols of eggs of each race were 24-ethylcholesterol (33.4-38.8% of total sterol), 24-ethylcholestanol (18.3-25.3%), 24-methylcholesterol (8.6-11.7%), 24-methylcholestanol (7.7-12.5%), and cholesterol (4.6-11.6%). Consequently, the major metabolic transformation performed by Meloidogyne females or eggs upon host sterols appeared to be saturation of the sterol nucleus. The free and esterified sterols of the same race did not differ appreciably, except for a slight enrichment of the steryl esters in cholesterol. Although the sterol composition of Meloidogyne eggs differed from that of other life stages of other genera of plant-parasitic nematodes, the three Meloidogyne races could not be distinguished from each other by their egg sterols. Ecdysteroids, compounds with hormonal function in insects, were not detected by radioimmunoassay in the Meloidogyne eggs either as free ecdysteroids or as polar conjugates. Key words: ecdysteroid, mass spectrometry, Meloidogyne arenaria, M. incognita, root-knot nematode, steroid, sterol.

Control of plant parasitic nematodes by intercropping with Tagetes minuta

Abstract: Marigold, Tagetes minuta, in mix-culture, significantly inhibited the root-knot development caused by Meloidogyne incognita on tomato and eggplant and reduced the multiplication of Rotylenchulus reniformis and Tylenchorhynchus brassicae on tomato, eggplant, cabbage and cauliflower. The growth of all the test plants was improved when marigolds were present. The root-exudates of T. minuta also exhibited strong nematicidal action.

Production and Partial Characterization of Stylet Exudate from Adult Females of Meloidogyne incognita.

Abstract: Adult females of Meloidogyne incognita were excised from tomato roots and incubated in 0.04 M phosphate buffered saline, pH 7.4 for 18-72 hours to allow accumulation of stylet exudate. Twenty-four percent of the females produced exudate during the initial 18-hour incubation period; 70% of those females producing exudate initially produced additional exudate during the subsequent 54-hour incubation period. Analysis of exudate by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of at least nine major protein bands. Differential staining with silver and Coomassie Brilliant Blue G-250 stains indicated that three of the bands were glycoproteins. Upon acid hydrolysis, 14 amino acids were detected in the stylet exudate. The basic amino acids lysine, histidine, and arginine comprised 21.8% of the total amino acids detected. No peroxidase activity was detected in the stylet exudates. Data presented extend and generally confirm prior work on the chemical composition of stylet exudate. Key words: root-knot nematode, biochemistry, peroxidase, amino acid, protein, stylet exudate, Meloidogyne incognita, giant cell.

Density-dependence and host-specificity of the nematode-trapping fungus Monacrosporium ellipsosporum

Abstract: SUMMARY The infection rate of Meloidogyne incognita juveniles was reduced by more than 90 O/o following migration through soil infested with the nematode-trapping fungus, Monacrosporium ellipsosporum to tomato roots. M. ellipsosporum reduced the number of juveniles penetrating tomato roots and the number of juveniles remaining in the soil twelve days post-treatment. The number of M. incognita juveniles entering roots decreased with increased M. ellipsosporum inoculum density. M. ellipsosporum sticky knob traps were tested for adhesion specificity to fiiteen different species of nematodes. Acrobeloides sp., Aphelenchoides sp., Aphelenchus avenae, Criconemella xenoplax, Meloidogyne incognita, Pratylenchus scribneri, Seinura oxuris, and Tylenchulus semipenetrans, adhered to the sticky knobs while Longidorus aji-icanus, Mesodo ylaimus sp., Paratrichodorus minor, Xiphinema anzericanunz, and Diplenteron sp. adults did not. Zotonchus brachyzaimus anly rarely adhered. Fifteen sugars were tested for suppression of adhesion of Panagrellus redivivus to the sticky knobs of M. ellipsosponim. Fucose, D-fructose and lactose suppressed adhesion of P. redivivus to the knobs at 20 mM, but some nematodes adhered even at 200 mM concentrations. Alpha-methyl-D-mannoside, L-sorbose, Darabinose, alpha-D-mellibiose, D (+) trehalose, and sucrose suppressed adhesion of P. redivivus at 200 mM but not at 20 mM Concentrations. N-acetyl-galactosamine and L-xylose did not suppress adhesion at 20 mM or 200 mM concentrations.

Interaction of root-knot nematode, Meloidogyne incognita with Fusarium oxysporum f. sp. Ciceri and F. solani on chickpea1

Abstract: The effect of the combined inocula of Meloidogyne incognita, Fusarium oxysporum and F. solani on growth of chickpea var. JG 62 was additive in nature. However, when nematode was established earlier than the two fungi, the resultant effect was more than simple additive. All the three organisms affected the rhizobial nodulation considerably. Occurrence of M. incognita in combination with F. oxysporum f. sp. ciceri and F. soloni, not only increased the severity of disease but also shortend the incubation period for disease expression. Further, when nematode preceded the fungi, plant drying due to infection by F. Solani appoared early. Rootrot index was also high when the nematode preceded F. solani. The nematode development and multiplication was adversely affected by F. solani irrespective of the time and level of inoculum. F. oxysporum f. sp. ciceri did not affect the nematode population significantly.

Nicotine Content of Tobacco Roots and Toxicity to Meloidogyne incognita

Abstract: The motility of Meloidogyne incognita second-stage juveniles (J2) and their ability to induce root galls in tomato were progressively decreased upon exposure to nicotine at concentrations of 1-100 μg/ml. EC₅₀ values ranged from 14.5 to 22.3 μg/ml, but J2 motility and root-gall induction were not eliminated at 100 μg/ml nicotine. Nicotine in both resistant NC 89 and susceptible NC 2326 tobacco roots was increased significantly 4 days after exposure to M. incognita. The increase was greater in resistant than in susceptible tobacco. Root nicotine concentrations were estimated to be 661.1-979.1 μg/g fresh weight. More M. incognita were detected in roots of susceptible than in roots of resistant tobacco. Numbers of nematodes within resistant roots decreased as duration of exposure to M. incognita was increased from 4 to 16 days. Concentrations of nicotine were apparently sufficient to affect M. incognita in both susceptible and resistant tobacco roots. Localization of nicotine at infection sites must be determined to ascertain its association with resistance.

Effect of combining soil solarization with certain nematicides on target and nontarget organisms and plant growth.

Abstract: 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 obtained by all of the treatments; however, none of the chemicals or combinations of chemicals and solarization controlled nematodes or P. ultimum significantly better than solarization alone. Numbers of cotton (Gossypium hirsutum cv. Acala SJ-2) seed-applied Trichoderma viride and Bacillus subtilis which colonized the plant rhizosphere were not affected. Yield of carrot and survival of cotton seedlings was sometimes increased by solarization and (or) chemical treatments. No significant phytotoxicity from soil treatments was found on cotton or carrot.

Use of Detached Leaves to Evaluate Tobacco Haploids and Doubled Haploids for Resistance to Tobacco Mosaic Virus, Meloidogyne incognita, and Pseudomonas syringae pv. tabaci

Abstract: Rufty, R. C., Wernsman, E. A., and Gooding, G. V., Jr. 1987. Use of detached leaves to evaluate tobacco haploids and doubled haploids for resistance to tobacco mosaic virus, Meloidogyne incognita, and Pseudomonas syringae pv. tabaci. Phytopathology 77:60-62. Development of disease-resistant cultivars in self-pollinated crops like virus Y. Detached leaves were maintained by immersing their petioles in tobacco (Nicotiana tabacum) can be greatly accelerated by evaluating water until symptoms appeared. Symptoms in detached leaves were similar populations of haploid plants derived from F1 hybrids resistant to various to those in intact plants, and disease reactions corresponded with wholediseases. A limitation of haploid breeding is the need to assess reactions to plant determinations. The technique can also be used with doubled haploid multiple pathogens on single plants. To avoid confounding systemic or or diploid populations segregating for disease resistance. The original lethal effects from inoculations with multiple pathogens, detached leaves intact plants with identified resistance may be evaluated for other traits, were inoculated separately with tobacco mosaic virus and Pseudomonas and susceptible genotypes may be discarded. Field evaluations for syringae pv. tabaci. Resistance to Meloidogyne incognita was identified by agronomic characteristics can then be performed on a population fixed for the associated reactions of detached leaves to the MsN R strain of potato disease resistance genes.

Elimination of nematodes from ginger (Zingiber officinale Roscoe) by tissue culture

Abstract: The rootknot nematode species Meloidogyne incognita and M. javanica pose a serious threat to the cultivation of ginger in South Africa. Tissue culture was investigated as a method of obtaining prop...

Field resistance to nonfumigant nematicides in Xiphinema index and Meloidogyne incognita

Abstract: Populations of Xiphinema index and Mebidogyne incognita were sampled from three vineyard plots. Two had been treated with either carbofuran or phenamiphos. The third was an untreated control. In the fourth year al1 three plots were treated with carbofuran. Assessments in the first year of treatment indicated that carbofuran applications had reduced the X. index population to one, half of the control levels. In the fourth year, however, the X. index population levels from the carbofuran and phenamiphos-treated vines were significantly higher than numbers taken from the control plot. Nematode numbers from the carbofuran-treated vines were more than three times the levels from the control plot. In vitro bioassays indicated that nematodes from the carbofuran and phenamiphos-treated plots had a higher tolerance to nonfumigant nematicides.

Evaluation of nematicidal properties in some latex bearing plants

Abstract: Incorporation of chopped shoots of latex bearing plants significantly suppressed the population build-up of Rotylenchulus reniformis and Tylenchorhynchus brassicae and reduced the root-knot development caused by Meloidogyne incognita. Chopped shoots of Ficus elastica gave greatest reduction in nematode population and root-knot development. These amendments also showed significant improvement in plant growth highest being in the treatment with chopped shoots of F. elastica.

Ce11 lysis activity of Meloidogyne gelatinous matrix

Abstract: M. i. a ete eleve sur racines excisees de tomate. 15 a 30 j. apres inoculation, les galles ont ete prelevees a trois jours d'intervalle, fixees puis traitees a la paraffine pour les observations histologiques

Comparative efficacy of neem and groundnut oil-cakes with aldicarb against meloidogyne incognita in tomato

Abstract: Investigations were carried out on tomato plants to evaluate the efficacy of neem and groundnut cakes in comparison with aldicarb on plant growth parameters, penetration, development and population build up of M. incognita juveniles. Growth response of plants to neem and aldicarb was better than groundnut cake and unamended control. In the early period of plant growth, neem and aldicarb treatments were at par but at the later phase, neem superseded aldicarb. Similarly, groundnut showed improvement over control which were earlier at par. In root and soil populations, least nematode number was recorded in aldicarb followed by neem, groundnut and control. Different treatments showed differential rates of development with fastest in control followed by groundnut, aldicarb and neem. Treatments also affected fecundity of the females and hatching of eggs.

Relationship between root respiration and seedling age in tomato cultivars infested by Meloidogyne incognita

Abstract: SUMMARY Measurements were made of respiration in the roots of tomato cultivars susceptible and resistant to Meloidogyne incognita. Nematode infestation of the susceptible cv. Roma VF caused an initial stimulation of the total respiration with an increase in the CN-sensitivity; the effect decreased and then disappeared as the seedlings aged. In the resistant cv. Rossol nematode infestation initially caused an inhibition of total respiration and a decrease in the CN-sensitivity; respiration and CN-sensitivity increased with seedling age. The activity of the alternative respiration pathway (m-chlorobenzhydroxamic acid-sensitive) was unchanged by nematode infestation in the resistant cultivar and increased markedly in the susceptible cultivar during the early stages of infestation.

Root-knot Nematode Management and Yield of Soybean as Affected by Winter Cover Crops, Tillage Systems, and Nematicides.

Abstract: Management of Meloidogyne incognita on soybean as affected by winter small grain crops or fallow, two tillage systems, and nematicides was studied. Numbers of M. incognita did not differ in plots planted to wheat and rye. Yields of soybean planted after these crops also did not differ. Numbers of M. incognita were greater in fallow than in rye plots, but soybean yield was not affected by the two treatments. Soybean yields were greater in subsoil-plant than in moldboard plowed plots. Ethylene dibromide reduced nematode population densities more consistently than aldicarb and phenamiphos. Also, ethylene dibromide increased yields the most and phenamiphos the least. There was a positive correlation (P = 0.001) of seed size (weight of 100 seeds) with yield (r = 0.79), indicating that factors affecting yield also affected seed size.

Usefulness of egg assays in nematode population-density determinations.

Abstract: Key words: Heterodera glycines, Meloidogyne arenaria, Meloidogyne hapla, Meloidogyne incognita, methods, population dynamics, root-knot nematodes, soybean cyst nematode.

Comparison of Compatible and Incompatible Response of Potato to Meloidogyne incognita.

Abstract: One susceptible (D6) and two resistant (E2 and N4) clones of Solanum sparsipilum × (S. phureja × haploid of S. tuberosum) were used to study the responses of potato roots and tubers to race 1 of Meloidogyne incognita (Kofoid & White) Chitwood. The compatible response was characterized by rapid penetration of large numbers of second-stage juveniles (J2) into roots, cessation of root growth, and occasional curving of root tips. The life cycle of M. incognita in the susceptible clone was completed in 25 days at 23-28 C. The incompatible response was characterized by penetration of fewer J2 into roots, necrosis of feeding sites within 2-7 days, and lack of nematode development. There were no differences in response of tubers from resistant and susceptible clones to nematode infection. Small numbers of J2 were detected in tubers, but they did not develop. Key words: Meloidogyne incognita, Solanum sparsipilum, Solanum phureja, Solanum tuberosum, potato, root-knot, resistance, susceptibility, compatibility.

Interaction between Meloidogyne incognita and Pseudomonas solanacearum on brinjal

Abstract: The combined pathogenic effects of Meloidogyne incognita and Pseudomonas solanacearum on a resistant brinjal cultivar (Pusa purple cluster) provided synergistic effect towards the development of wilt symptoms and influenced different plant growth parameters such as shoot length. shoot weight, root length and root weight. production of 2.8 per cent wilt in plants occurred at tooo larvae + 47 per cent transmittance and the other at 2000 larvae + 85 per cent transmittance (bacterial sespension) levels of inoculum. Although the results of nematode and bacteria on shoot length showed a significant trend, their combined insignificant differences emphasised the inhibitory effect of one on the other in affecting the host or may be the infection of nematode rendered the plant unsuitable for bacterial infection. A significant difference in shoot weight, reduction in root length and a decrease in root weight over control was observed. Population of nematodes present inside the soil after the harvesting of plants increased at different levels of initial nematode inoculum with three different levels of bacterial inoculum.

Effects of Nematicides and Herbicides Alone or Combined on Meloidogyne incognita Egg Hatch and Development.

Abstract: 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 juveniles that hatched from day 6 to day 8 were used as inoculum to determine the effects of the chemicals on penetration, development, and reproduction of M. incognita on tomato 4, 16, and 32 days after inoculation. F, F + T, and F + M inhibited hatching; whereas, C, T, M, C + T, and C + M did not affect hatching, penetration, development of females, or reproduction. Since so few juveniles hatched from the fenamiphos treatments, we were not able to use them for the postinfection development study. There was no apparent reduction in the effect of the nematicides by the herbicides.

Plant parasitic nematodes associated with black pepper (Piper nigrum L.) in Kerala

Abstract: Fourteen genera of plant parasitic nematodes are associated with black pepper (Piper nigrum.), in nine major pepper growing districts of Kerala. Meloidogyne incognita, Radopholus similis, Trophotylenchulus piperis, Rotylenchulus reniformis and Helicotylenchus sp. are the major nematode species associated with the crop. M. incognita is widely distributed in Calicut, Cannanore and Wynad districts. R. similis is a major problem in Calicut, Cannanore and Idukki districts. In Quilon, Trivandrum and Wynad districts, the incidence of R. similis is low. T. piperisis also widely distributed in all the pepper growing areas in Kerala and its occurrence is high in Idukki district. The concomitant infestation of M. incognita, R. similis and T. piperis in the roots of black pepper is high compared to their solitary infestation.