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

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.

In: Nematology

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.

In: Nematology

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.

In: Crustaceana

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.

In: Nematology

Summary

Bark beetles (Curculionidae: Scolytinae) have a significant economic impact on forest stands and agricultural settings in Israel. We focus on nematodes associated with bark beetles collected from different host plants attacked by Scolytinae. The sampling was conducted in forest plantations and fruit tree orchards in several areas in Israel. A total of 430 beetle specimens of eight species were examined for the presence of nematodes. Fifteen nematode species were detected and identified based on molecular and morphological characteristics. Among the examined scolytids, the pine bark beetle, Orthotomicus erosus, the most widely distributed and frequently occurring species in Israel, was accompanied by the highest nematode diversity, with 11 species recovered. Nematode associations with the almond bark beetle (Scolytus amygdali), the olive bark beetle (Phloeotribus scarabaeoides) and the fig bark beetle (Hypoborus ficus) were recorded for the first time. Our study thus supplies novel information on scolytid-associated nematodes in Israel.

In: Nematology