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.

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 Trichodorid Species 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.