DPG Reports © Eugen Ulmer KG, Stuttgart
J.Plant Dis.Protect. 3/2013
Report on the 41
stmeeting of the DPG-Working Group “Nematology”
The annual meeting was held on March 12 and 13 at Syn- genta breeding station in Bad Salzuflen. Like in previous years about 70 participants from Germany, Switzerland, Netherlands and Sweden with scientific background, related to industry and extension joint the meeting. The main topic of the meeting was related to plant parasitic nematodes exclusively, due to the fact that the joint meetings together with the working group “free living nematodes” will be held every second year since 2012. This was decided aiming to meet deviating interests of participants. A broad variety of themes was discussed throughout four sessions covering the topics: Breeding and use of tolerant cultivars, estimation of field populations and control, interactions between micro- organisms and nematodes and finally new topics on diag- nostics and epidemiology of quarantine nematodes. Prior to the meeting participants could take opportunity to visit the breeding station. Excess to all abstracts is provided at the DPG homepage (www.phytomedizin.org). Abstracts of au- thorized contributions are given below.
The working group acknowledges the broad endorsement and the excellent organization of the meeting with special thanks to Dr. Enno Blumenberg, Mrs. Prüssner and the many helpers around. The next meeting together with the working group “free living nematodes” will take place at the Senckenberg Museum in Görlitz.
Matthias Daub & Ulrike Hakl, DPG Working Group
“Nematology”
Nematicidal potential of plant extracts against the root-knot nematodes, Meloidogyne hapla and M. incognita
Beira Hailu Meressa1, Heinz-Wilhelm Dehne2 &
Johannes Hallmann1
1 Julius Kühn-Institut, Institut for Epidemiology and Pathogen Diagnostics, Toppheideweg 88, 48161 Münster
2 Institute for Crop Science and Resource Conservation (INRES), Department of Phytomedicine, University of Bonn, Nußallee 9, 53115 Bonn, Germany
e-mail: beira-hailu.meressa@jki.bund.de
Environmental concerns and high costs of synthetic nemati- cides have increased interest in searching for alternative control measures such as plant products. Within this respect, the nematicidal potential of both aqueous and ethanol extracts from corm of Rumex abyssinicus Jacq, roots of Plumbago dawei Rolfe and inflorescence of Maesa lanceolata Forssk was evaluated. Each extract was tested at five con- centrations and seven exposure periods for inhibition of Meloidogyne hapla and M. incognita. In addition, ethanol
extracts of each plant species were tested in the greenhouse at three different concentrations on tomato (Solanum lyco- persicum cv. Moneymaker) inoculated with 100 juveniles of M. incognita and M. hapla per 100 ml soil, respectively. Re- sults of the in vitro test revealed that extracts of all three plant species significantly inhibited M. hapla and M. incog- nita compared with the control. At the highest concentra- tions and longest exposure periods, ethanol extracts of all three plant species achieved 100% mortalitiy of both nema- tode species. The LC50 of M. lanceolata varied significantly with time of exposure and extraction procedure (p< 0.001).
In general, the LC50 was lower for the ethanol extract than the aqueous extracts. For P. dawei the LC50 of the ethanol extract was significantly lower (p< 0.05) than that of the aqueous extract within the first one hour of exposure; for R. abyssinicus this was the case for the first 30 min of expo- sure time. In the greenhouse experiment root and shoot fresh weight of tomatoes treated with the highest extract concentration of P. dawei and M. lanceolata were signifi- cantly higher when compared with the untreated plants (p< 0.001). In contrast, shoot and root fresh weight of tomatoes treated with R. abyssinicus did not differ from the untreated control plants, most likely because of phytotoxic effects observed immediately after application. Moreover, nematode densities were significantly reduced following application of the highest concentration of all three plant extracts (p< 0.001). The application of these plant species as botanical nematicides against Meloidogyne is highly promising as these plants are abundantly available in the reach of every grower in Ethiopia.
Distribution of Pine Wood Nematodes, Bursaphelenchus xylophilus, in a batch of wood packaging material Anne Sophie van Bruggen, AM de Heij, C Cornelisse &
Loes JMF den Nijs
NVWA, department NRC, Geertjesweg 15, 6706 EA Wageningen, The Netherlands e-mail: l.j.m.f.den.nijs@minlnv.nl
Wood packaging material (pallets, crates, dunnages etc) should be treated according to ISPM 15 to prevent the inter- national transport and spread of diseases, nematodes and insects. International Standards for Phytosanitary Measures No. 15 (ISPM 15) is an International phytosanitary measure developed by the International Plant Protection Convention (IPPC). ISPM 15 describes that the wood should be heated (56C° for 30 min, HT) or methybromide should be used (MB). After proper treatment the nematodes, Bursaphelen- chus xylophilus (PWN), should be killed. To check whether the treatments are performed properly the NPPO of the
142 XXX: XXX
J.Plant Dis.Protect. 3/2013
Netherlands takes samples of wood packaging material. In a sample from a pallet from Portugal carrying natural stone B. xylophilus was detected. All the pallets of the batch were traced and transferred to the NPPO. The batch consisted of 29 pallets. Samples were taken and analyzed for the pres- ence of nematodes. In 10 pallets B. xylophilus was found, 9 of these pallets were marked (HT), the other showed no mark of treatment. In 2 of the contaminated pallets B. xylo- philus was found together with B. fungivorus. One pallet was analyzed further, to find out where B. xylophilus was located in the pallet, in the planks or in the blocks that separate the planks. From each item (block or plank) a sample was taken for further analysis. Preliminary results show that the nem- atodes were only found in the planks. Additional research will be carried out to include more pallets and to study the distribution of B. xylophilus within the plank.
Development and validation of a real-time PCR assay for the detection and identification of the root-knot nematode Meloidogyne enterolobii, a new EPPO A2 list quarantine organism
Sebastian Kiewnick, Andrea Braun-Kiewnick & Jürg E Frey Agroscope, Schloss 1, 8820 Wädenswil, CH
e-mail: sebastian.kiewnick@acw.admin.ch
Root-knot nematodes (Meloidogyne spp.) pose a significant risk to agricultural production systems all over Europe.
Meloidogyne enterolobii is a polyphagous species and has been found on many host plants including ornamentals and important agricultural crops. Meloidogyne enterolobii is con- sidered to be a very pathogenic species, and shows a high re- production potential on root-knot nematode-resistant plants which makes it extremely difficult to manage. Interceptions of ornamental plants infested with M. enterolobii by Euro- pean NPPOs, lead to the addition of this species to the EPPO (European Plant Protection Organization) A2 list in 2010.
The presence of M. enterolobii in greenhouses in Switzer- land and France clearly demonstrated that pathways for introduction do exist. To identify these pathways and to ensure that appropriate phytosanitary measures and man- agement strategies are available to protect European agri- culture against quarantine nematodes, reliable detection and identification tools are needed. Real-time PCR assays demonstrated their usefulness for detection and identifica- tion of quarantine nematodes in the past. Therefore, Lock Nucleic Acid Probe based assays (LNA) were designed on the basis of the second intergenic spacer (IGS2) region of the ribosomal DNA cistron and the cytochrome oxidase c subunit I (COI) and tested using different platforms and chemistry. Specificity of assays was confirmed with 14 M. enterolobii, 17 other Meloidogyne populations (8 species)
and three other species. Testing the assays on 2 platforms with different chemistry revealed a sensitivity of one juve- nile in a background of 1000 nematodes or one juvenile per 100 ml soil. Currently, a test performance study under the EUPHRESCO framework is underway to validate the per- formance of the COI based assay with 7 partners all over Europe.
Population density suppression of Globodera pallida in a multi-year microplot trial with potato monoculture Caroline Eberlein1, Stefan Vidal2, J Ole Becker3 &
Andreas Westphal1
1 Julius Kühn-Institut, Institute for Plant Protection in field crops and grassland, Messeweg 11/12, 38104 Braunschweig
2 Georg-August-University, Department of Crop Sciences/
Agricultural Entomology, Grisebachstrasse 6, Göttingen, Germany
3 Department of Nematology, University of California, 3401 Watkins Drive, Riverside, CA 92521, U.S.A e-mail: andreas.westphal@jki.bund.de
Potato cyst nematodes have quarantine status in Europe to contain these important pests. The decline of population densities of plant-parasitic nematodes in monocultures of susceptible hosts and otherwise disease-conducive condi- tions is an example of soil suppressiveness. The presence of a plant-parasitic nematode can lead to an increase of nema- tode antagonists, e. g. fungi, that parasitize females, and eggs of endoparasitic nematodes have been implicated in such suppressiveness. The objectives of this study were to determine a) if soil under a potato monoculture becomes suppressive to Globodera pallida Pa3, and b) if Dactylella oviparasitica, a known fungal parasite of cyst and root-knot nematodes, can suppress population densities of G. pallida.
From 2009 to 2012, G. pallida-infested microplots were cropped with susceptible potatoes. At each planting and harvest, cysts were extracted, the eggs counted and cate- gorized into healthy and diseased. In the first season, the number of healthy eggs of G. pallida increased. In 2010, the plots were divided into two groups with either non-treated or receiving D. oviparasitica-amendment treatments. Based on the total number of extracted eggs, the percentage of diseased eggs increased from about 2% in 2009 to almost 70% in 2012. Although D. oviparasitica parasitized eggs of G. pallida in vitro, its efficacy in vivo remains unknown. The fungus did not additionally increase the number of diseased nematode eggs in the amended microplots. Apparently, the potato cyst nematode population was compromised under the potato monoculture. Further studies will focus on causes leading to such high proportions of diseased eggs.
