The Pinewood Nematode, Bursaphelenchus xylophilus

Proceedings of an International Workshop, University of Évora, Portugal, August 20-22, 2001

Edited by Manuel Mota and Paulo Vieira

According to the European Plant Protection Organization, the pinewood nematode (PWN), Bursaphelenchus xylophilus is a quarantine organism at the top of the list of the pathogenic species. PWN may be found in North America (Canada, USA and Mexico) and in East Asia (Japan, Korea, China and Taiwan) and has a highly destructive capability towards conifers, in a relatively short time, causing serious economic damage in Japan, China and Korea. This nematode surveying is extremely important and a correct identification of nematode species associated with conifers is essential. Several conifers species are very susceptible (Pinus sylvestris, Pinus nigra and Pinus pinaster), the last one (maritime pine) is a particulary important economic specie in Portugal, and in southern Europe.
In 1999, this nematode was found and identified for the first time in Portugal and in Europe. During 1999 and 2000, the Portuguese government, following an alert provided to European Community officials initiated an extensive national survey. During 2000 and 2001, research has been carried out regarding the morphobiometric as well as molecular (DNA: ITS-RFLP) characterization of the collected populations, as well as closely related species of Bursaphelenchus.
The book details the Proceedings of an international workshop held at the University of Évora in 2001, covering all major aspects of the bioecology of the pinewood nematode (PWN), Bursaphelenchus xylophilus, its insect vectors and effects on the tree.
Topics covered are: global issues and national surveys; morphology and molecular methods of identification of PWN; ecology and epidemiology; quarantine issues; tree physiology, resistance and histopathology; biology of PWN and relationships to its cerambycid vectors; control methods. General quarantine and political views are also presented.

Ana Rita Santos, Alexander Ryss, Manuel Mota and Paulo Vieira

Abstract

The vulval pattern of six species of the genus Bursaphelenchus (B. abruptus, B. conicaudatus, B. fraudulentus, B. luxuriosae, B. mucronatus and B. xylophilus) was studied using scanning electron microscopy. A terminology for the vulval region structures observed is proposed herein and illustrated by micrographs and line drawings. It was shown that, of the studied species, only B. mucronatus and B. xylophilus share an identical morphology of the vulval region, all other species differing significantly from each other and from both B. mucronatus and B. xylophilus. This study indicates the diagnostic potential for variation in vulval morphology within Bursaphelenchus and it is recommended that such features are recorded in all future descriptions.

Oleg Kulinich, Manuel Mota, Paulo Vieira and Alexander Ryss

Abstract

The 75 valid species of the genus Bursaphelenchus are listed together with their synonyms. Diagnostic characters and their states are discussed and illustrated. Tabular and traditional text keys are provided for the genus. Two new subspecies are proposed to distinguish populations of B. piniperdae and B. poligraphi, as described by Rühm (1956), from the original descriptions of these species published by Fuchs (1937). Known records of Bursaphelenchus species with their associated natural vectors, plants and plant families are given. Dendrograms of species relationships (UPGMA, standard distance: mean character difference) based on combined taxonomic characters and also on spicule characters only, are provided. Discussion as to whether the species groups are natural or artificial (and therefore purely diagnostic) is based on their relationships in the dendrogram and the vector and associated plant ranges of the species. Of the six species groups distinguished, two appear to represent natural assemblages, these being the xylophilus-group (with ten species) and the hunti-group (seven species), of which two, B. cocophilus and B. dongguanensis, form the cocophilus-cluster which is separated on the dendrogram from the main clusters. The remaining four species groups appear to be artificial and purely diagnostic in function, namely the aberrans-group (four species); the eidmanni-group (six species); the borealis-group (five species), and the piniperdae-group (43 species). Two new subspecies, both in the piniperdae-group, viz. B. piniperdae ruehmpiniperdae n. subsp. and B. poligraphi ruehmpoligraphi n. subsp., are proposed and diagnosed from B. piniperdae piniperdae and B. poligraphi poligraphi the respective type subspecies. Bursaphelenchus dongguanensis is regarded as being a valid member of the genus and its transfer to Parasitaphelenchus is rejected.

Václav Čermák, Václav Čermák, Paulo Vieira, Václav Čermák, Paulo Vieira, Mária Čudejková, Václav Čermák, Paulo Vieira, Mária Čudejková, Vladimir Gaar, Václav Čermák, Paulo Vieira, Mária Čudejková, Vladimir Gaar, Kateřina Tománková, Václav Čermák, Paulo Vieira, Mária Čudejková, Vladimir Gaar, Kateřina Tománková, Kateřina Mikušková, Václav Čermák, Paulo Vieira, Mária Čudejková, Vladimir Gaar, Kateřina Tománková, Kateřina Mikušková, Jonathan D. Eisenback, Václav Čermák, Paulo Vieira, Mária Čudejková, Vladimir Gaar, Kateřina Tománková, Kateřina Mikušková, Jonathan D. Eisenback and Manuel Mota

Science Stand

Crossing Borders between Sciences, Arts, and Humanities in a Decentralized Science Dissemination Program

Series:

Luís Paulo de Carvalho Piassi, Rui Manoel de Bastos Vieira and Emerson Izidoro dos Santos

Mehmet Dayi, Monica Calin, Süleyman Akbulut, Jianfeng Gu, Thomas Schröder, Paulo Vieira and Helen Braasch

Bursaphelenchus andrassyi sp. n., found in conifer wood samples from Romania and Turkey, is characterised morphologically and genetically. Bursaphelenchus andrassyi sp. n. clearly belongs to the sexdentati group, having a terminal bursa, four lateral lines, a very small female ‘vulval flap’, strongly arcuate spicules and the typical position of caudal papillae of males. It is morphologically most similar to B. vallesianus and B. sexdentati. It can be differentiated from B. vallesianus by the usually subcylindrical female tail with rounded or wedge-shaped terminus vs conical female tail with a more or less rounded terminus, slightly different shape of spicules (low square condylus, lacking a distinct cucullus, pointed rostrum) and from B. sexdentati by lacking a distinct post-vulval constriction, shorter stylet and shorter spicules. The species status is supported by ITS-RFLP patterns and sequencing results of both partial 18S and 28S rDNA regions.

Rony R. R. Vieira, Paulo J. Rieger, Viviane Cichowski and Marcelo A. A. Pinheiro

The juvenile development of the freshwater crab Dilocarcinus pagei Stimpson, 1861 was studied under laboratory conditions, focusing on setae morphology. The ovigerous females were collected manually associated with water hyacinth at the Municipal Dam of São José do Rio Preto (São Paulo, Brazil). The specimens were raised in the laboratory under constant aeration, photoperiod (12 : 12 h) and temperature (27 ± 1°C). Twelve juvenile stages were obtained with descriptions of the main morphological characters that allow their identification are presented. Fourteen types of setae were discovered: dentate, denticulate, serrulate, papposerrate, cuspidate, plumose, plumodenticulate, plumoserrulate, simple, pappose, brush, curved, nail and setules. The greatest diversity of setae was found on the mouth appendages, especially the maxillule. The gill ontogeny and sexual dimorphism becomes apparent from the second juvenile stage onwards. At the third juvenile stage, the carapace begins to exhibit a wider shape, becoming similar to that of the adults.

Dijalma Silva, Paulo Pereira, Guy de Capdeville, Roberto Vieira, Michel Nicole, Antônio Moita, Ana Cristina Gomes, Regina Carneiro, Sarazete Izidia Vaz Pereira and Jean Kleber Mattos

Abstract

Pfaffia glomerata is a medicinal plant widely distributed in Brazil, which is considered the world's greatest supplier of P. glomerata roots. Among active ingredients contained in this plant, the steroid β-ecydisone (20E) is the most important compound extracted from roots. This steroid presents therapeutic properties for the treatment of diabetes and haemorrhoids, besides having bioenergy, tonic and aphrodisiac effects. The root-knot nematode Meloidogyne spp. is a major limiting factor in root production. Recent studies showed resistance of accessions of P. glomerata to Meloidogyne incognita. The aims of this work were: i) to correlate the concentration of 20E with resistance and susceptibility of P. glomerata accessions to M. incognita in inoculated and non-inoculated plants; ii) to study the effect of the parasitism of M. incognita on the concentration of the steroid 20E in the roots; and iii) to clarify resistance mechanisms by comparing the response of a highly resistant UFV with a highly susceptible accession (Farm) to nematode infection. The concentration of 20E in the healthy susceptible Farm accession was significantly higher than in the healthy resistant UFV accession, showing that the resistance mechanism was not related to 20E concentrations. Plants of the Farm accession infected with M. incognita showed higher levels of 20E than the non-infected control. A positive and significant Pearson correlation coefficient was observed between 20E concentrations and gall indexes. Resistance of UFV to the root-knot nematode M. incognita was associated with unidentified factors that limited nematode penetration or emigration of second-stage juveniles and with post-penetration responses, including the hypersensitive response. Giant cells were sometimes found in the resistant cultivar, but displayed a highly vacuolated and degraded cytoplasm with thinner cell walls than those induced in the susceptible accession. Microscope observations under UV light showed a strong autofluorescence, suggesting that phenolic compounds may be involved in ginseng UFV resistance.