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Le Rheu, France

Gamel S.,Nematology Unit | Huchet E.,FN3PT RD3PT French Federation of Seed Potato Growers | Huchet E.,French National Institute for Agricultural Research | Le Roux-Nio A.-C.,FN3PT RD3PT French Federation of Seed Potato Growers | And 2 more authors.
European Journal of Plant Pathology

Several conventional PCR tests have been developed for the identification of the European quarantine root-knot nematodes Meloidogyne chitwoodi and M. fallax but data are lacking for the evaluation of their performance in terms of sensitivity, repeatability, reproducibility and specificity against a large range of populations. This study evaluated the performance criteria of three conventional PCR tests recommended by the consensus diagnostic protocol for Meloidogyne chitwoodi and Meloidogyne fallax published by the European and Mediterranean Plant Protection Organization (EPPO): a species-specific PCR (IGS target), a SCAR PCR, and a rDNA ITS PCR-RFLP. Evaluation was carried out with DNA extracts from juveniles, males and females according to EPPO recommendations for test validation. A minimum of 34 populations of target and non target nematode species were tested to check the specificity of these three PCR assays. The three PCR tests were ranked according to their specificity (with regard to cross reaction with other nematodes species or genus) and their sensitivity (detection of a single juvenile or mixed with other species). The species-specific PCR proved to be more sensitive but less specific than the SCAR PCR. The PCR-RFLP enables the identification of several Meloidogyne species but profile analysis can be difficult when several species are present in the mixture. Specific PCR products and RFLP profiles were also observed for M. arenaria and M. enterolobii, and described for M. minor and M. artiellia. © 2013 KNPV. Source

Grenier E.,French National Institute for Agricultural Research | Fournet S.,French National Institute for Agricultural Research | Petit E.,French National Institute for Agricultural Research | Anthoine G.,Nematology Unit

The cyst nematode, Globodera pallida, is a major pest of potato, a plant native to South America. To investigate its phylogeography, an extensive sampling survey was conducted in 2002 in Peru and has laid the foundations of the ancient evolutionary history of this nematode species. We argue that the uplift of the Andes Mountains has triggered a variety of adaptive biotic radiations for Solanaceous plant-parasitic nematodes and has represented a key factor for the evolution and specialisation of Globodera species. We discuss the consequences of the wide genetic diversity observed in South American populations on the efficiency and durability of potato resistance and also the reliability of current molecular identification tools for quarantine purposes. Finally, we emphasise the need to get a more in-depth taxonomic characterisation of some of these nematode populations, and to conduct more extensive sampling in South America, especially south of Lake Titicaca, in order to understand fully potato cyst nematode evolution and their adaptation to their host plants. © 2010 Brill Academic Publishers. Source

Application of organic soil amendments is a traditional control method for plant-parasitic nematodes and it is considered a part of nematode-management programs. A variety of organic amendments, such as animal and green manures, compost, nematicidal plants and proteinous wastes, are used for this purpose, but nematode control efficacy is not always satisfactory. Elucidation of nematode-control mechanisms in amended soil may lead to improved efficacy or the development of more effective control techniques, although the effects of organic amendments on nematodes, microbial communities, plants and soil environments are very complex. Possible mechanisms involved in nematode suppression are: (1) release of pre-existing nematicidal compounds in soil amendments, (2) generation of nematicidal compounds, such as ammonia and fatty acids, during degradation, (3) enhancement and/or introduction of antagonistic microorganisms, (4) increase in plant tolerance and resistance, and (5) changes in soil physiology that are unsuitable for nematode behavior. Combinations of these mechanisms, rather than a single one, appear to produce nematode suppression in amended soils. © 2009 Elsevier B.V. All rights reserved. Source

Edelstein M.,Newe Yaar Research Center | Oka Y.,Nematology Unit | Burger Y.,Newe Yaar Research Center | Eizenberg H.,Newe Yaar Research Center | Cohen R.,Newe Yaar Research Center
Israel Journal of Plant Sciences

The responses of diverse cucurbit accessions, including cucumber, melon, watermelon, pumpkin, and Momordica spp., to Meloidogyne javanica and M. incognita, were evaluated.For melons and cucumbers, severity of galling was significantly affected by nematode species, but no significant effects of cultivars or cultivar x nematode species interactions on the level of galling were observed. Severity of galling was always higher for M. incognita than for M. javanica in any cultivar tested. Galling indices in melons were 0.3 and 1.6, and in cucumber 2.8 and 3.7, for M. javanica and M. incognita, respectively. Watermelon did not did show root galling when inoculated with M. javanica and showed a very low index (0-0.3) with M. incognita. Cucurbita accessions evaluated were the most susceptible. Galling index in pumpkin inoculated with M. javanica was significantly lower than that caused by M. incognita. Cucurbita moschata and the intraspecific hybrids of C. moschata were more resistant than commercial cultivars of melon, cucumber, and watermelon used as susceptible controls. Two Momordica charantia accessions out of 12 tested exhibited no or very low root galling in response to M. incognita and M. javanica. These findings indicate high resistance but not immunity to the nematodes. ©2010 Science From Israel / LPPLtd. Source

The fluoroalkenyl fluensulfone, known to have strong nematicidal activity against Meloidogyne spp. (root-knot nematodes), was evaluated in vitro and in soil against the migratory nematodes Bursaphelenchus xylophilus, Aphelenchoides besseyi, Aphelenchoides fragariae, Ditylenchus dipsaci, Pratylenchus penetrans, Pratylenchus thornei and Xiphinema index. RESULTS: B. xylophilus and D. dipsaci were not immobilised by 48 h in vitro exposure to up to 16 mg L-1 of fluensulfone. A. besseyi and A. fragariae were affected by 8 mg L-1, the highest concentration used for these nematodes. More than 60% of P. penetrans and P. thornei were immobilised by 4 mg L-1 of fluensulfone; however, exposure of P. penetrans to the compound prior to inoculation did not affect their root penetration ability. The immobilisation rate of X. index was increased by 48 h exposure to even 1.0 mg L-1 of fluensulfone. Incorporation of over 2 mg L-1 of fluensulfone into the soil reduced populations of P. penetrans and P. thornei before and after planting lettuce and chickpea respectively. The efficacy of fluensulfone against the tested nematodes was the same or higher than that of fenamiphos in most cases. CONCLUSION: A. besseyi, A. fragariae, B. xylophilus and D. dipsaci were tolerant to fluensulfone and fenamiphos. P. penetrans, P. thornei and X. index were affected by fluensulfone, but nematicidal activity was much lower than that reported for root-knot nematodes. © 2014 Society of Chemical Industry. Source

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