四川省茂县花椒根结线虫病病原鉴定

为明确四川省茂县花椒根结线虫的种类,通过根结线虫雌虫和2龄幼虫的形态特征及雌成虫的会阴花纹、雌虫酯酶同工酶及分子生物学检测（rDNA-ITS区和rRNA-IGS区）,对花椒根结线虫进行了种类鉴定。三种方法的结果均表明在茂县地区花椒上发现的根结线虫为北方根结线虫（Meloidogynehapla）,这是我国首次报道在花椒上发现北方根结线虫病,四川省是北方根结线虫新的分布区。     

Yield Responses in Relation to the Chemical Control of Root-knot Nematodes in Southern Italy

Nematicide trials have been conducted in Southern Italy to determine the yield response of tobacco, tomato and egg-plant. The nematode species involved were mainly Meloidogyne incognita (Kofoid & White) Chitwood and M. arenaria (Neal) Chitwood. Many nematicides have an impact also on other soil pathogens or even on insects, so that the yied increase observed in the field has to be considered as a combined effect. On tobacco, most of the nematicides gave positive results, but it appeared that there might be important differences according to the variety considered. In certain tomato fields, which had not been specially attacked by Meloidogyne, the positive effects seemed to be also due to the insecticidal or fungicidal effect of the chemicals. No statistically significant yield increases were, however, obtained on treated egg-plant fields.     

九叶青花椒根结线虫病的病原鉴定

为确定四川省蓬溪县九叶青花椒种植区发病植株花椒根结线虫的种类, 进而为九叶青花椒根结线虫病防治提供依据, 本文根据根结线虫雌虫与2龄幼虫的形态特征及雌成虫的会阴花纹、雌虫酯酶同工酶图谱, 并结合特异性扩增及rDNA-ITS扩增, 根据ITS序列构建系统发育树, 对该地区九叶青花椒根结线虫病的病原进行了种类鉴定。结果表明该病原为南方根结线虫Meloidogyne incognita (Kofold & White) Chitwood。这是我国首次在九叶青花椒上发现南方根结线虫。     

Rôle économique et importance des Meloidogyne en Europe et dans le bassin Méditerranéen

Les nématodes appartenant au genre Meloidogyne peuvent être considérés à I'échelle mondiale comme le groupe le plus important de ces parasites. Les « anguillules des racines noueuses >>, ou « rootknot nematode « des auteurs anglosaxons, ont été longtemps jugées comme étant graves seulement dans les pays tropicaux ou méditerranéens chauds. Les différentes espèces sont souvent difficiles à distinguer on les a confondues jusqu'à une date récente et nombre d'entre elles restent encore à décrire — neuf ont été signalées en Europe.
La fréquence et la gravité des attaques semblent augmenter dans les régions méditerranéennes, surtout sur cultures maraîchères, florales, fruitières et sur coton ( M. arenaria [Neal] Chitwood, M. incognita [Kofoid et White] Chitwood, M. javanica [Treub] Chitwood). Ces espèces posent aussi de graves problèmes dans toutes les serres européennes. En Europe occidentale, M. hapla Chitwood attaque de multiples cultures légumières: M. naasi Franklin, découvert et décrit récemment, devient un ennemi grave des céréales. Les pertes dues à ces nématodes représentent plusieurs pour cent du produit brut des cultures intéressées dans les aires géogra-phiques infestées.     

Screening of common bean (Phaseolus vulgaris) for resistance against temperate root-knot nematodes (Meloidogyne spp.)

BACKGROUND: An important part of the production area of common bean (Phaseolus vulgaris L.) in Belgium is located on the sandy soils of the provinces of Antwerp and Limburg where Meloidogyne chitwoodi (Golden), M. fallax (Karssen) and M. hapla (Chitwood) are present. The host plant status of ten bean cultivars for root‐knot nematodes was determined by evaluating penetration, development and egg mass formation after inoculation with second‐stage juveniles. RESULTS: The tested cultivars were poor to good hosts for M. chitwoodi, non‐hosts or bad hosts for M. fallax and excellent hosts for M. hapla. Significantly fewer M. fallax were found in the roots, and their development was delayed. Penetration of M. hapla took place over a longer period than that of M. chitwoodi and M. fallax. The number of mature females of M. chitwoodi in cv. Polder 6 weeks after inoculation was no different from that in other cultivars, although fewer egg masses were found on this cultivar in the screening test. There was no influence of M. chitwoodi on vegetative growth of cv. Polder. CONCLUSION: The differences found in host plant status of bean cultivars stress the importance of a correct diagnosis of the Meloidogyne species in agricultural fields. Cultivar Polder showed potential as a trap crop for M. chitwoodi. Copyright © 2011 Society of Chemical Industry     

甘肃省党参根结线虫病发生、分布及病原种类鉴定

为明确甘肃省党参根结线虫病的发生、分布及病原种类,在甘肃省党参主产区调查、统计田间根结线虫病发生情况,并通过形态学和分子生物学方法进行种类鉴定。结果表明,甘肃省6个党参主产区均有根结线虫病发生,病田率、病株率分别为40.7%、13.2%,病情指数为10.4。依据根结线虫各虫态的形态测量值和雌虫会阴花纹等特征,将危害党参的根结线虫初步鉴定为北方根结线虫Meloidogyne hapla Chitwood, 1949。rDNA-ITS区段和28S rDNA D2D3区段序列比对和系统发育树显示,6个根结线虫群体无核苷酸差异,与多个北方根结线虫聚为一支且有较高的置信度。利用特异性引物Mh-F/Mh-R扩增得到北方根结线虫的特异性片段,大小为462 bp。故综合形态学和分子生物学特征,将危害甘肃省党参的根结线虫鉴定为北方根结线虫。     

Nematicidal activity of anion transport blockers against Meloidogyne incognita, Caenorhabditis elegans and Heterorhabditis bacteriophora

BACKGROUND: Because methyl bromide has been phased out as a soil sterilant, new nematicides are urgently needed. Four different chemical classes of organic acids acting as anion transport (AT) blockers were tested against a free-living nematode, Caenorhabditis elegans Maupas, a plant-parasitic nematode, Meloidogyne incognita (Kofoid and White) Chitwood, and an entomopathogenic nematode, Heterorhabditis bacteriophora Poinar, in toxicity bioassays. The materials tested were DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid), 9-AC (anthracene-9-carboxylic acid), NPPB [5-nitro-2-(3-phenylpropylamino)benzoic acid] and IAA-94 (indanyloxyacetic acid). RESULTS: All the compounds showed slowly developing nematicidal activity against second-stage juveniles of M. incognita and adults of C. elegans, but not against H. bacteriophora infective-stage juveniles. The LC(50) values of these compounds were < 50 mg L(-1) after 48 and 72 h incubation, while at 168 h incubation the LC(50) values were < 10 mg L(-1) for both sensitive species. Across both species and time, the LC(50) values generally differed no more than twofold among the four compounds tested in this study. In contrast, none of the compounds (200 mg L(-1)) caused more than control mortality to H. bacteriophora, even after 168 h of incubation. CONCLUSION: These compounds are potential leads for commercial nematicides. The insensitivity to H. bacteriophora is consistent with the natural exposure of this nematode to DST (3,5-dihydroxy-4-isopropylstilbene), a stilbene produced by its symbiotic bacterium. Based on the known activity of the compounds used in this study, it is suggested that anion transporters form the probable target sites for DIDS, 9-AC, NPPB and IAA-94 in nematodes.     

Dose-response effects of clove oil from Syzygium aromaticum on the root-knot nematode Meloidogyne incognita

BACKGROUND: Clove oil, derived from the plant Syzygium aromaticum (L.) Merr. & Perry, is active against various organisms, and was prepared in a soy lecithin/detergent formulation to determine concentrations active against the root-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood. RESULTS: In microwell assays, the mean effective clove oil concentration that reduced egg hatch by 50% (EC(50)) was 0.097% (v/v) clove oil; the EC(50) for second-stage juvenile (J2) viability was 0.145% clove oil (compared with carrier control treatments). Volatiles from 5.0% clove oil reduced nematode egg hatch in water by 30%, and decreased viability of hatched J2 by as much as 100%. Reductions were not as large with nematodes in carrier. In soil trials with J2 recovered from Baermann funnels, the EC(50) = 0.192% clove oil (compared with water controls). CONCLUSION: The results demonstrated that the tested formulation is active against M. incognita eggs and J2, that the EC(50) values for J2 in the microwell studies and the soil recovery tests were similar to each other and that direct contact with the clove oil is needed for optimal management results with this natural product.     

The influence of the nematode Meloidogyne incognita on competition between Solanum nigrum and tomato

The effect of Meloidogyne incognita (Kofoid & White) Chitwood, 1949, on the competitive relationship between tomato (Lycopersicon esculentum Mill.) and black nightshade (Solanum nigrum L.) was investigated under glasshouse conditions. Two intraspecific competition treatments were set up for the crop and the weed, and five interspecific treatments where the emergence of S. nigrum plants was progressively delayed in relation to tomato. Nematodes reproduced in all inoculated plants, their multiplication rates being much higher in tomato than in S. nigrum plants. Under nematode-free conditions, intraspecific competition of tomato was more severe than the interspecific competition shown by the weed S. nigrum. Tomato was as tronger competition with S. nigrum than the weed was with itself. However, when infested by M. incognita, both species displayed a similar competitive ability. Tomato yield losses increased with prolonged weed competition but were greater under nematode-infested conditions.     

花生根结线虫病产量损失估计与防治指标的研究

1990—1992年采用池栽与田间考查相结合的方法,研究了花生根结线虫的为害与产量损失率之间的关系及其防治指标。结果表明,土壤中线虫初始密度的对数值与花生荚果产量损失率及病情指数之间的关系均符合logistic曲线;而病情指数、收获前土壤中的线虫密度与花生产量呈显著负相关。得出防治指标为:中等产量水平的田块中播种前每kg土壤中含有侵染期幼虫和卵31.14条(粒)。     

海南岛南药根结线虫种类鉴定

运用比较形态学、同工酶和mtDNA-PCR对采自海南岛9个市县的南药根结线虫进行种类鉴定,结果发现有南方根结线虫、象耳豆根结线虫、爪哇根结线虫、花生根结线虫和西班牙根结线虫等5种根结线虫危害海南岛南药。5种根结线虫均能在海巴戟上寄生与危害,而南方根结线虫寄主非常广泛,可危害大多数调查的药用植物。     

Chemical Root-Dips for Control of Root-knot Nematode Attacking Tomato

Abstract

Dimethoate 0.5% for 6 h was the most effective dip for suppressing the root-knot nematode, Meloidogyne incognita (Kofoid and White, 1919) (Chitwood, 1949). It was better than all the other treatments except 0.025% dimethoate for 6 h. Dimethoate at 0.1 and 0.2% and 0.2% parathion and diazinon as 6 h root-dips were phytotoxic. Diazinon controlled the nematode poorly and malathion was ineffective.     

Use of crop residues for the control of Meloidogyne incognita under laboratory conditions

This laboratory study evaluates the biofumigant effect of different organic materials with the aim of developing non-chemical alternatives for the management of Meloidogyne incognita (Kofoid & White) Chitwood populations. Sources of organic material from the production system were selected with the aim of reducing agricultural residue accumulation problems as well as decreasing the costs due to the use of chemical fertilizers and pesticides. The selected materials were residues from pepper, strawberry, tomato and cucumber crops, orange juice industry residues, commercial manure and sheep manure, applied at different dosages. Two biofumigation assays were performed under laboratory conditions, using alkaline soils from the Torreblanca area (Murcia, Spain) and acidic soils from the Villa del Prado area (Madrid, Spain). The assays evaluated the effect of the treatments on M. incognita juveniles and other soil organisms, the nematode galling index on tomato roots (susceptible cv. Marmande) grown in the biofumigated soil and soil fertility parameters. The results showed that all biofumigant materials significantly decreased M. incognita populations and galling indices in tomato cv. Marmande. A greater effect was observed on galling indices when applying crop residues together with manure than with the residues alone. Biofumigation had a general beneficial effect on soil fertility, generally increasing nitrogen, organic carbon, pH and potassium levels, and also calcium levels when crop residues of pepper and strawberry were applied. There were no important variations in the number of saprophagous nematodes, dorylaimids and enchytraeids.     

Differences in Feeding Sites Induced by Root-Knot Nematodes, Meloidogyne spp., in Chickpea

ABSTRACT Root-knot nematodes (Meloidogyne spp.) are sedentary, obligate endoparasites in plants, where they induce specialized feeding sites. The feeding sites act as strong metabolic sinks to which photosynthates are mobilized. The histopathological modifications in the nematode-induced feeding sites of artificially inoculated chickpea cv. UC 27 were qualitatively and quantitatively compared using five isolates of M. artiellia and one isolate each of M. arenaria, M. incognita, and M. javanica. All Meloidogyne isolates infected chickpea plants, but root gall thickening was significantly less for M. artiellia isolates than for the other Meloidogyne species. Nevertheless, neither the number of giant cells in the feeding site (averaging four to six) nor the area of individual giant cells was influenced by nematode species or isolate. However, the number of nuclei per giant cell was significantly smaller, and the maximum diameters of nuclei and nucleoli were significantly greater, in giant cells induced by M. artiellia isolates than in those induced by M. arenaria, M. incognita, or M. javanica. In a second experiment, M. artiellia-induced giant cells in faba bean and rapeseed also contained a small number of large nuclei.     

Effects of DL-methionine on hatching and activity of Meloidogyne incognita eggs and juveniles

Several concentrations of DL-methionine were tested in the laboratory for their effects on Meloidogyne incognita (Kofoid & White) Chitwood egg hatching and juvenile activity in aqueous suspensions and infested soil. After 7 days in methionine solutions, the proportions of hatched eggs were reduced by 23.3% at 0.25 mg litre(-1) methionine and by 76.4% at 25 g litre(-1) when compared with controls in tap water. An effect of methionine solutions on juvenile activity was also apparent after 24 h in the 25 g litre(-1) treatment, where the percentage of active M incognita juveniles was reduced by 16.3%. Further reductions in nematode mobility were observed as the time of exposure increased, and at lower methionine concentrations over longer exposure times. When methionine solutions were applied to soil infested with M incognita, reductions in egg hatching and juvenile activity were observed at 0.1 and 1 mg methionine g(-1) soil in both sand and clay-loam soils. The percentage of hatched eggs one week after methionine application at rates of 1 mg g(-1) was lower in sand (5.6%) and clay-loam soil (20.8%) than in controls where egg hatch was 52.0% and 48.0% in sand and soil, respectively. Non-active juveniles were found at 1 mg methionine g(-1) soil one week after its application to soil.     

Virulence development and genetic polymorphism in Meloidogyne incognita (Kofoid & White) Chitwood after prolonged exposure to sublethal concentrations of nematicides and continuous growing of resistant tomato cultivars

BACKGROUND: The root‐knot nematode, Meloidogyne incognita (Kofoid & White) Chitwood, is an important plant pathogen damaging to tomato. Continuous use of resistant tomato cultivars and nematicides for its effective management might lead to resistance break‐up or nematicide failure. Genetic variability and virulence in M. incognita on susceptible Pusa Ruby tomato were analysed by bioassay, esterase and DNA polymorphism after a 5 year weekly exposure to carbofuran, carbosulfan, cadusafos and triazophos at 0.0125, 0.0250 and 0.0500 µg g^?1. Virulence in M. incognita after a 5 year multiplication on resistant tomatoes was assessed. RESULTS: The nematicidal treatments resulted in the development of virulent M. incognita populations. Their invasion potential increased significantly after continuous exposure to low concentrations of the nematicides. Also, growing resistant tomato cultivars for ten successive seasons resulted in a 6.6% increase in the invasion potential. These virulent populations exhibited 1–3 additional esterase and DNA bands compared with untreated populations. CONCLUSION: A 5 year exposure of M. incognita to sublethal concentrations of nematicides or resistant tomato cultivars exerted enough selection pressure to cause genomic alterations for virulence development. Isozyme markers can be used for rapid and precise diagnostics of field populations by advisory services, enabling judicious remedial management decisions. Copyright © 2009 Society of Chemical Industry     

Two new species of Myliocotyle (Monogenea: Monocotylidae) from the gills of Aetomylaeus maculatus and A. nichofii (Elasmobranchii: Myliobatidae) from Sarawak, Borneo, Malaysia

Myliocotyle borneoensis sp. n. and M. multicrista sp. n. (Monocotylidae: Heterocotylinae) are described from the gills of the mottled eagle ray, Aetomylaeus maculatus (Gray), and the banded eagle ray A. nichofii (Bloch et Schneider) (Myliobatidae), respectively, collected from the northern coast of Malaysian Borneo. These are the first monogeneans to be described on elasmobranchs from Borneo. The formerly monotypic Myliocotyle (for M. pteromylaei) was distinguished from other monocotylids by the distribution and morphology of the eight sclerotised dorsal haptoral accessory structures and the morphology of the male copulatory organ. However, we have determined that M. pteromylaei has ten structures on the dorsal surface of the haptor. Myliocotyle borneoensis is distinguished from M. pteromylaei by the morphology of the male copulatory organ and its accessory piece. Myliocotyle multicrista has 12 sclerotised dorsal haptoral accessory structures and a male copulatory organ with two accessory pieces. Additional sclerotised ridges across the ventral surfaces of each loculus (except the posterior-most pair) are also present in M. multicrista. The diagnosis for Myliocotyle is revised given our discovery of additional dorsal haptoral accessory structures in the type species and to accommodate other new characters of the two new species. Anterior secretions of Myliocotyle are discussed.     

Nematicidal efficacy of MCW‐2, a new nematicide of the fluoroalkenyl group,against the root‐knot nematode Meloidogyne javanica

BACKGROUND: The small number of available nematicides and restrictions on the use of non‐fumigant nematicides owing to high toxicity to human and non‐target organisms hinder effective nematode control. The nematicidal efficacy of MCW‐2, a new nematicide of the fluoroalkenyl group, was evaluated against the root‐knot nematode Meloidogyne javanica (Treub.) Chitwood. RESULTS: MCW‐2 showed irreversible nematicidal activity against second‐stage juveniles of M. javanica in vitro, following exposure for 48 h at concentrations as low as 0.5 mg L^?1, in contrast to fenamiphos or cadusafos. When exposed to MCW‐2 for shorter periods, motile juveniles became immobile with time after rinsing in water. MCW‐2 at 8 mg L^?1 inhibited nematode hatching, which, however, recovered after rinsing in water. In pot and plot experiments, 0.5 mg MCW‐2 L^?1 soil and 2 kg MCW‐2 ha^?1, respectively, controlled M. javanica similarly to or better than fenamiphos or cadusafos at the same concentrations or at their recommended doses. In the soil, the nematicidal activity of MCW‐2 was less persistent than that of fenamiphos. CONCLUSION: MCW‐2 has potential to be used as a new non‐fumigant nematicide that probably has a novel mode of action. Copyright © 2009 Society of Chemical Industry     

Management of root-knot nematode,Meloidogyne incognita,infesting Egyptian henbane,Hyoscyamus muticus L., by the use of nematicides and oilcakes

Studies were carried out to evaluate the efficacy of various nematicides: aldicarb (Temik 10G), and carbofuran (Furadan 3G) at 3 kg a.i./ha, mocap (Ethoprop 10G) at 5 kg a.i./ha and oilcakes ofcastor ( Ricinus communis L., 4.2% N), groundnut ( Arachis hypogea L., 7% N), linseed ( Linum usitassimum L., 4.7% N), neem ( Azadirchta indica Juss, 5.4% N) and mustard ( Brassica compestris L., 4.8% N) at 1 g N/kg of soil in the form of soil amendments for the management of Meloidogyne incognita (Kofoid & White) Chitwood infesting Egyptian henbane ( Hyoscyamus muticus L.). All the treatments resulted in a significant increase in length, fresh and dry weights ofhenbane plants as compared with untreated inoculated plants. The maximum improvement in plant growth parameters was observed in plants treated with mocap followed by neem cake, aldicarb, carbofuran, castor, mustard, groundnut and linseed cakes respectively. Application of nematicides and oilcakes suppressed the pathogenic effect of M. incognita on Hyoscyamus muticus and resulted in significant reduction in gall intensity and population density ofroot-knotnematode in roots and soil. In comparison to untreated inoculated plants the highest reduction in root-knot index was noted in plants treated with mocap, whereas the lowest reduction was observed in plants treated with linseed cake.     

Molecular diagnostics for the sigatoka disease complex of banana

ABSTRACT The Sigatoka disease complex of banana involves three related ascomycetous fungi, Mycosphaerella fijiensis, M. musicola, and M. eumusae. The exact distribution of these three species and their disease epidemiology remain unclear, because their symptoms and life cycles are rather similar. Disease diagnosis in the Mycosphaerella complex of banana is based on the presence of host symptoms and fungal fruiting structures, which hamper preventive management strategies. In the present study, we have developed rapid and robust species-specific molecular-based diagnostic tools for detection and quantification of M. fijiensis, M. musicola, and M. eumusae. Conventional species-specific polymerase chain reaction (PCR) primers were developed based on the actin gene that detected DNA at as little as 100, 1, and 10 pg/mul from M. fijiensis, M. musicola, and M. eumusae, respectively. Furthermore, TaqMan real-time quantitative PCR assays were developed based on the beta-tubulin gene and detected quantities of DNA as low as 1 pg/mul for each Mycosphaerella sp. from pure cultures and DNA at 1.6 pg/mul per milligram of dry leaf tissue for M. fijiensis that was validated using naturally infected banana leaves.