The aim of this review was to undertake a survey of researchers working with plant-parasitic nematodes in order to determine a ‘top 10’ list of these pathogens based on scientific and economic importance. Any such list will not be definitive as economic importance will vary depending on the region of the world in which a researcher is based. However, care was taken to include researchers from as many parts of the world as possible when carrying out the survey. The top 10 list emerging from the survey is composed of: (1) root-knot nematodes (Meloidogyne spp.); (2) cyst nematodes (Heterodera and Globodera spp.); (3) root lesion nematodes (Pratylenchus spp.); (4) the burrowing nematode Radopholus similis; (5) Ditylenchus dipsaci; (6) the pine wilt nematode Bursaphelenchus xylophilus; (7) the reniform nematode Rotylenchulus reniformis; (8) Xiphinema index (the only virus vector nematode to make the list); (9) Nacobbus aberrans; and (10) Aphelenchoides besseyi. The biology of each nematode (or nematode group) is reviewed briefly.

/pdf/top-10-plant-parasitic-nematodes-in-molecular-plant-22vrx0hc6m.pdf

Top 10 plant-parasitic nematodes in molecular plant pathology

Top 10 plant parasitic nematodes in molecular plant pathology in (Abstracts from the 6th International Congress of Nematology, Cape Town, South Africa, 4-9 May 2014)

Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens which threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant-pathogenic oomycete species based on scientific and economic importance. In total, we received 263 votes from 62 scientists in 15 countries for a total of 33 species. The Top 10 species and their ranking are: (1) Phytophthora infestans; (2, tied) Hyaloperonospora arabidopsidis; (2, tied) Phytophthora ramorum; (4) Phytophthora sojae; (5) Phytophthora capsici; (6) Plasmopara viticola; (7) Phytophthora cinnamomi; (8, tied) Phytophthora parasitica; (8, tied) Pythium ultimum; and (10) Albugo candida. This article provides an introduction to these 10 taxa and a snapshot of current research. We hope that the list will serve as a benchmark for future trends in oomycete research.

/pdf/the-top-10-oomycete-pathogens-in-molecular-plant-pathology-3gxpkolrjj.pdf

The Top 10 oomycete pathogens in molecular plant pathology

Meloidogyne species: a diverse group of novel and important plant parasites

https://espace.library.uq.edu.au/view/UQ:705404/UQ705404_OA.pdf

Emerging microbial biocontrol strategies for plant pathogens.

Plant-parasitic nematodes devastate crops worldwide, in turn impacting international trade, social and economic development. Effective control of nematodes is essential for crop protection, and requires an understanding of nematode biology, taxonomy, population dynamics and sampling methods. Providing a broad introduction to nematodes as plant parasites, this book begins by describing nematodes by genera, and builds on this foundation to detail nematode biology and pest management, including biological and chemical control. Chapters are authored by international experts and enhanced by extensive illustrations and focus boxes. Fully updated throughout, this new edition is an essential resource for postgraduate students, extension officers, researchers and crop protection scientists

Root-knot nematodes

In Europe, root-knot nematodes are increasingly important. Out of more than 90 Meloidogyne species currently described, 23 have been found on the continent. In the cooler climates, Meloidogyne hapla , M. naasi , M. chitwoodi and M. fallax are prevalent. Meloidogyne arenaria , M. javanica and M. incognita are the most common species in warmer conditions of southern Europe, but also in glasshouses in northern Europe. Morphological identification of root-knot nematodes is difficult and time consuming; therefore, many research groups have been developing molecular techniques for identification of Meloidogyne species. Meloidogyne chitwoodi and M. fallax are quarantine organisms and subject to regulations, and the highly aggressive M. enterolobii has been added to the EPPO alert list. Differences between temperate and tropical Meloidogyne species and their prevalence in Europe imply the need for different management strategies in south and north Europe. Possible crop rotations for the control of root-knot nematodes are limited due to the wide host range of several important species. The banning of methyl bromide and restrictions on other fumigant pesticides in the EU have increased the application of biofumigation significantly in south Europe. The egg-parasitising fungus Paecilomyces lilacinus is commercialised in Germany and applied as dispersible granules for application in water. Intensive research is conducted on the egg-parasitising fungus Pochonia chlamydosporia , and the obligate parasitic bacterium Pasteuria penetrans. European research has paid much attention to resistance breeding and selection. The Mi gene of tomato is widely used but resistance-breaking populations of M. incognita and M. javanica have been reported in different countries.

Root-knot nematodes ( Meloidogyne spp.) in Europe

The encounter between Meloidogyne species and tomato is many centuries old. Meloidogyne species are known to cause high levels of economic loss worldwide in a multitude of agricultural crops, including tomato. This review was initiated to provide an overview of the damage potential of Meloidogyne spp. on cultivars of tomato ( Solanum lycopersicum ), and to compile the different studies done on the management of Meloidogyne spp. on tomato with particular emphasis on the Mi resistance gene. Numerous studies have been conducted to assess the damage potential of root-knot nematode on various tomato cultivars; its yield loss potential ranges from 25 to 100%. A range of management options from using synthetic nematicides to soilless cultures have been tried and are available for managing Meloidogyne spp. Resistant commercial cultivars and rootstocks carrying the Mi gene have been used successfully to manage Meloidogyne incognita , M. javanica and M. arenaria . However, virulent populations have been detected. Relying on a single root-knot nematode management strategy is an outdated concept and different management options should be used in an integrated management context by considering the whole system of disease management. In future management of Meloidogyne species, care must be taken in directly extrapolating the tolerance limit determined elsewhere, since it is affected by many factors such as the type of initial inoculum and physiological races of Meloidogyne spp., environmental conditions, types of cultivars and experimental approaches used.

Wim Wesemael

Papers

Top 10 plant-parasitic nematodes in molecular plant pathology

Top 10 plant parasitic nematodes in molecular plant pathology in (Abstracts from the 6th International Congress of Nematology, Cape Town, South Africa, 4-9 May 2014)

Root-knot nematodes

Root-knot nematodes ( Meloidogyne spp.) in Europe

Tomato (Solanum lycopersicum) and root-knot nematodes (Meloidogyne spp.) – a century-old battle