Pflanzenparasitäre Nematoden im Ökologischen Landbau – Probleme und Lösungsansätze (Workshop)

Ziel dieses Workshops ist es, umfassende Informationen zur Bedeutung pflanzenparasitärer Nematoden im Ökologischen Landbau bzw. Bioanbau in der Schweiz und Deutschland vorzustellen, die Ursachen der Problematik und Lösungsansätze aufzuzeigen und zu diskutieren, sowie weiteren Forschungsbedarf zu identifizieren. In diesem Workshop sollen pflanzenparasitäre Nematoden hinsichtlich ihrer Biologie und der durch sie verursachten Symptome kurz vorgestellt werden. Des Weiteren werden die Verbreitung und wirtschaftliche Schäden, Lösungsansätze für den Gemüsebau und den Ackerbau vorgestellt und diskutiert. Dieser Workshop bietet die Möglichkeit den Erfahrungsaustausch zwischen Produzenten, Wissenschaftlern und Beratern zu fördern und Informationen zur Bedeutung pflanzenparasitärer Nematoden im ökologischen Landbau zu vermitteln. Folgende Punkte sollen im Rahmen dieses Workshop behandelt werden: Kulturen bzw. Anbausysteme in denen bevorzugt Schäden durch Nematoden auftreten. Einfluss von Standorteigenschaften wie Bodenart, Humusgehalt und pH-Wert. Gibt es Unterschiede zwischen Ökolandbau und konventionellen Landbau? Möglichkeiten Nematodenschäden im Ökolandbau zu verhindern

Effect of plant resistance and BioAct WG (Purpureocillium lilacinum strain 251) on Meloidogyne incognita in a tomato-cucumber rotation in a greenhouse

BACKGROUND The effectiveness of combining resistant tomato with BioAct WG (Purpureocillium lilacinum strain 251, Pl251) against Meloidogyne incognita was assessed in a tomato-cucumber rotation in a greenhouse over 2 years. Additionally, the enzymatic activity of the fungus, the percentage of fungal egg and juvenile parasitism, cardinal temperatures and the effect of water potential on mycelial growth and the soil receptivity to Pl251 were determined in vitro. RESULTS Plant resistance was the only factor that suppressed nematode and crop yield losses. Percentage of egg parasitism in plots treated with BioAct WG was less than 2.6%. However, under in vitro conditions, Pl251 showed protease, lipase and chitinase activities and parasitised 94.5% of eggs, but no juveniles. Cardinal temperatures were 14.2, 24–26 and 35.4¿°C. The maximum Pl251 mycelial growth was at -0.25 MPa and 25¿°C. Soil temperatures and water potential in the greenhouse were in the range of the fungus. However, soil receptivity was lower in greenhouse soil, irrespective of sterilisation, than in sterilised sand. CONCLUSION Plant resistance was the only factor able to suppress nematode densities, disease severity and yield losses, and to protect the following cucumber crop. Environmental factors involved in soil receptivity could have negatively affected fungus effectiveness.Postprint (updated version

Screening of sugar beet pre-breeding populations and breeding lines for resistance to Ditylenchus dipsaci penetration and reproduction

Ditylenchus dipsaci is an economically important plant-parasitic nematode affecting European sugar beets. To date, no sugar beet cultivars carrying resistance against D. dipsaci are available to farmers. To find potentially resistant sugar beet lines restricting reproduction and penetration of D. dipsaci, three consecutive in vivo bioassays were carried out. The first experiment determined the penetration rate of D. dipsaci in 79 breeding lines and 14 pre-breeding populations. Based on these results, D. dipsaci penetration and reproduction resistance of eight genotypes was intensively investigated. It could be demonstrated that none of the genotypes showed resistance towards D. dipsaci. However, a high variation of the penetration rate by D. dipsaci was observed among the genotypes. The breeding line ‘DIT_119’ effectively reduced D. dipsaci penetration (34.4 ± 8.8 nematodes/plant at 22 days post-planting) compared to the susceptible control (109.0 ± 16.9) while ensuring a yield comparable to non-inoculated plants. However, the breeding line ‘DIT_119’ did not reduce D. dipsaci reproduction. The paternal line of the cultivar BERETTA KWS, demonstrating a high tolerance to D. dipsaci crown rot symptoms, did not reduce penetration and reproduction. Thus, no correlation can be established between reduced penetration rates, reproduction, and tolerance to D. dipsaci. This study provides an essential basis for the development of resistant sugar beet cultivars to D. dipsaci. The variations observed among genotypes now need to be confirmed with larger-scale screenings

A time travel through nematology in Germany – From the beginnings to the use of artificial intelligence

Das Nachrichtenblatt für den Deutschen Pflanzenschutzdienst, unser heutiges Journal für Kulturpflanzen, feiert seinen 100. Geburtstag. Seinem Ziel, „den im praktischen Pflanzenschutzdienst Tätigen Belehrung und Informationen (zu) übermitteln“, wie Otto Appel zur Einführung schrieb, ist es bis heute treu geblieben. Dies gilt auch für den Bereich der Nematologie. Die Themen haben sich dabei über die Zeit weiterentwickelt. Standen früher Biologie und Wirtspflanzenspektrum einzelner Arten pflanzenparasitärer Nematoden im Fokus des Interesses, so sind es heute Wirt-Parasit Interaktionen, Resistenz und Toleranz von Kulturpflanzen oder der Einfluss von Klimawandel und Globalisierung auf die Verbreitung und das Schadpotenzial der Nematoden. Der vorliegende Beitrag blickt zurück auf die Themen vor 100 Jahren, stellt am Beispiel laufender Arbeiten am Julius Kühn-Institut aktuelle Forschungsthemen vor und gibt einen Ausblick auf die Themen der Zukunft.The Nachrichtenblatt für den Deutschen Pflanzenschutzdienst, today's Journal of Cultivated Plants, celebrates its 100th birthday. It has remained true to its goal of “providing instruc­tion and information to those involved in the practical plant protection service” to this day as stated in its first issue by Otto Appel. This also applies to the field of nematology. The topics have expanded over time and developed further on an international level. While the main focus was initially on the biology and host plant spectrum of the various nematode species, today it is on host-parasite interactions, resistance and tolerance of cultivated plants and the influence of climate change and globalization on the distribution and harmful effects of nematodes. The present article looks back at the topics 100 years ago, presents current research topics using the example of ongoing work at the Julius Kühn Institute and provides an outlook on the topics of the future

Isolation of Bacteria with Antifungal Activity against the Phytopathogenic Fungi Stenocarpella maydis and Stenocarpella macrospora

Stenocarpella maydis and Stenocarpella macrospora are the causal agents of ear rot in corn, which is one of the most destructive diseases in this crop worldwide. These fungi are important mycotoxin producers that cause different pathologies in farmed animals and represent an important risk for humans. In this work, 160 strains were isolated from soil of corn crops of which 10 showed antifungal activity against these phytopathogens, which, were identified as: Bacillus subtilis, Pseudomonas spp., Pseudomonas fluorescens, and Pantoea agglomerans by sequencing of 16S rRNA gene and the phylogenetic analysis. From cultures of each strain, extracellular filtrates were obtained and assayed to determine antifungal activity. The best filtrates were obtained in the stationary phase of B. subtilis cultures that were stable to the temperature and extreme pH values; in addition they did not show a cytotoxicity effect against brine shrimp and inhibited germination of conidia. The bacteria described in this work have the potential to be used in the control of white ear rot disease

Lateral flow immunoassay for on-site detection of Xanthomonas arboricola pv. Pruni in symptomatic field samples

[EN] Xanthomonas arboricola pv. pruni is a quarantine pathogen and the causal agent of the bacterial spot disease of stone fruits and almond, a major threat to Prunus species. Rapid and specific detection methods are essential to improve disease management, and therefore a prototype of a lateral flow immunoassay (LFIA) was designed for the detection of X. arboricola pv. pruni in symptomatic field samples. It was developed by producing polyclonal antibodies which were then combined with carbon nanoparticles and assembled on nitrocellulose strips. The specificity of the LFIA was tested against 87 X. arboricola pv. pruni strains from different countries worldwide, 47 strains of other Xanthomonas species and 14 strains representing other bacterial genera. All X. arboricola pv. pruni strains were detected and cross-reactions were observed only with four strains of X. arboricola pv. corylina, a hazelnut pathogen that does not share habitat with X. arboricola pv. pruni. The sensitivity of the LFIA was assessed with suspensions from pure cultures of three X. arboricola pv. pruni strains and with spiked leaf extracts prepared from four hosts inoculated with this pathogen (almond, apricot, Japanese plum and peach). The limit of detection observed with both pure cultures and spiked samples was 10(4) CFU ml(-1). To demonstrate the accuracy of the test, 205 samples naturally infected with X. arboricola pv. pruni and 113 samples collected from healthy plants of several different Prunus species were analyzed with the LFIA. Results were compared with those obtained by plate isolation and real time PCR and a high correlation was found among techniques. Therefore, we propose this LFIA as a screening tool that allows a rapid and reliable diagnosis of X. arboricola pv. pruni in symptomatic plants.The work was supported by the following: Instituto Nacional de Tecnologia Agraria y Alimentaria, Project RTA-2011-00140-C03-01 (http://www.inia.es), PLS MTG EMN MML; Instituto Nacional de Tecnologia Agraria y Alimentaria, FPI-INIA grant (http://www.inia.es), PLS; Generalitat Valenciana (Prometeo II 2014/040) (http://www.gva.es), PN RP AM; Ministerio de Economia y Competitividad (MINECO) (CTQ2013-45875R) (http://www.mineco.gob.es), PN RP AM; European Social Fund, PLS MTG EMN MML; and European Regional Development Fund, PLS MTG EMN MML.López-Soriano, P.; Noguera Murray, PS.; Gorris, MT.; Puchades, R.; Maquieira Catala, A.; Marco-Noales, E.; López, M. (2017). Lateral flow immunoassay for on-site detection of Xanthomonas arboricola pv. Pruni in symptomatic field samples. 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