Nematode Vectors of Plant Viruses

Although nematodes had long been suspected as vectors of soil borne plant diseases, unequivocal proof of their implication was not forthcoming until 1958 when Professor William Hewitt and his colleagues in California demonstrated experimentally that Xiphinema ~ was the vector of grapevine fanleaf virus. This opened up a new and exciting field in plant pathology and discoveries quickly followed of other nematode species associated with soil-borne diseases of many different crops and in several countries. After the initial enthusiasm of discovering new vectors and new viruses there followed a period of consolidation in which research workers sought answers to tantalising questions about the location of the virus within the nematode, the factors governing the close speci ficity between virus and vector; and more mundane but equally important and compelling questions about life cycles, geographical distribution, host relations, morphology and taxonomy. No other group of nematodes has attracted such a concentrated effort involv ing many different scientific specialisations and yielding so much progress in a relatively short time. The NATO Advanced Study Institute held at Riva dei Tessali, Italy, during 19 May to 2 June, 1974, provided the forum for a critical discussion of all aspects of biology of virus vector nema todes.

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Although nematodes had long been suspected as vectors of soil­ borne plant diseases, unequivocal proof of their implication was not forthcoming until 1958 when Professor William Hewitt and his colleagues in California demonstrated experimentally that Xiphinema ~ was the vector of grapevine fanleaf virus. This opened up a new and exciting field in plant pathology and discoveries quickly followed of other nematode species associated with soil-borne diseases of many different crops and in several countries. After the initial enthusiasm of discovering new vectors and new viruses there followed a period of consolidation in which research workers sought answers to tantalising questions about the location of the virus within the nematode, the factors governing the close speci­ ficity between virus and vector; and more mundane but equally important and compelling questions about life cycles, geographical distribution, host relations, morphology and taxonomy. No other group of nematodes has attracted such a concentrated effort involv­ ing many different scientific specialisations and yielding so much progress in a relatively short time. The NATO Advanced Study Institute held at Riva dei Tessali, Italy, during 19 May to 2 June, 1974, provided the forum for a critical discussion of all aspects of biology of virus vector nema­ todes.

Contenu
Virus Vector Nematode Taxonomy and General Introduction.- Morphology of Longidoridae.- Taxonomy of Xiphinema Cobb, 1913.- A Lattice for the Identification of Species of Xiphinema Cobb, 1913.- Taxonomy of Longidorus (Micoletzky) Filipjev and Paralongidorus Siddiqi, Hooper and Khan.- Morphology of Trichodorid Nematodes.- Taxonomy of Trichodoridae.- Functional Morphology of Dorylaimida.- Cytogenetics and Reproduction in Xiphinema and Longidorus.- Short Report: Embryology and hatching of Trichodorus similis and Longidorus elongates.- Cell Structure and Function An Introduction to Ultrastructure.- Ultrastructure of Dorylaimidae.- The Structure and Musculature of the Feeding Apparatus in Longidorus and Xiphinema.- The Ultrastructure of the Feeding Apparatus in Trichodorids.- Feeding of Trichodorus, Longidorus and Xiphinema.- Some Features of Nematode-borne Viruses and their Relationship with the Host Plants.- Acquisition, Retention and Transmission of Viruses by Nematodes.- Short Reports: Some Non-rosaceous Trees and Shrubs as Hosts to Nematodeborne Viruses.- Distribution of Artichoke Italian Latent Virus and its Nematode Vector in Apulia.- Nettlehead and Related Hop Diseases associated with the Hop Strain of Arabis Mosaic Virus and its Vector Xiphinema diversicaudatum.- Virus Vector Species of Xiphinema and Longidorus in relation to Certification Schemes for Fruit and Hops in England.- Nematode transmitted Virus in British Columbia, Canada.- Transmission of Cowpea Mosaic by Xiphinema basiri in Western Nigeria.- Ecology of Xiphinema and Longidorus.- The Ecology of Trichodorus.- Short Reports: A Preliminary Note on the Geographical Distribution of Trichodorids in the British Isles.- A Preliminary Study of the Factors influencing the Distribution of TrichodoridSpecies in the British Isles.- Geographical Distribution of Xiphinema and Longidorus in the British Isles.- Known Distribution of Species of Longidorus and Xiphinema in Norway.- Longidorus and Xiphinema in Sweden.- Nematodes of the Family Longidoridae in Bulgaria.- Geographical Distribution of Xiphinema in Spain.- The Distribution of Virus-transmitting Nematodes in Undisturbed Biotopes of Lower Saxony.- Longidorus and Xiphinema in the Sudan.- Distribution of Xiphinema spp. in South African Vineyards.- Relation between Xiphinema and Longidorus and their, Host Plants.- Short Report: The Effect of Longidorus elongatus on Seedling Fruit Tree Rootstocks in Poland.- Factors influencing the Movement of Nematodes in Soil.- Dynamics of the Plant Nematode System.- Chemical Control of Nematode Vectors of Plant Viruses.- Short Reports: Chemical Control of Trichodorids and of Transmission of Tobacco Rattle Virus.- Chemical Control of Corky Ringspot Disease on Potatoes in Florida, USA.- Nematode Control in Established Red Raspberry Planting.- Chemical and Cultural Control of Nettlehead and Related Virus Diseases of Hop.- Control of Xiphinema in South Africa.- List of Lecturers.- List of Participants.