FOREWARD

The formal conferences of the Thessaloniki symposia were followed by a four-day post conference tour, June 19–21, to Peloponnesus, Southern Greece, which was attended by 33 foreign and 2 Greek participants. There, apricot orchards were visited in Argolis and Corinthia, and the plum pox virus (PPV) problem was observed. During the conference week, there was another tour, on June 15, in the peach growing area of West Macedonia, where the Naoussa Pomology Institute was visited. PPV is a problem in this area, too.

More than 150 scientists attended the conferences, coming from Australia, Austria, Belgium, Bulgaria, Canada, Chile, Czechoslovakia, W. Germany, Finland, France, Greece, Israel, Italy, Japan, Netherlands, Norway, Poland, Spain, Switzerland, United Kingdom, U.S.A., and Yugoslavia. Colleagues from Egypt, Romania, and U.S.S.R., also, submitted their summaries.

The 14th International Symposium on Fruit Tree Virus Diseases included one opening, six oral and three poster sessions, one round table discussion, and part of the Business Meeting. Two oral and half poster sessions, and the round table discussion were devoted to PPV, underlining its phytopathological importance.

The present volume, Acta Horticulturae No.235, contains 48 formal papers, the minutes of round table discussion, written by F. Dosba, and the second ammendment to Acta Horticulturae 130, 319–326, on detection of virus and virus-like diseases of fruit trees, decided at the Business Meeting and written by L. Kunze. The volume adds information on several aspects of Fruit Tree Virology, including disease occurrence, host range, new pathogens and diseases, new strains, strain interaction, cultivar reactions, molecular biology, new techniques, diagnostic and detection methods, indexing, cleaning propagation material, and certification schemes. Use of modern detection techniques, as ELISA, complementary DNA probes, and complementary RNA probes, are of paramount importance for massive, quick, and reliable detection and diagnosis. A great part of molecular biology work presented in the Symposium was on PPV; comparison with other potyviruses on coat protein and nucleic acid basis, coat protein structure, expression of coat protein region in E. coli; the last is a significant attainment towards the goal to create resistance in susceptible species by genetic engineering. In the round table discussion, in which participated a large number of scientists, future collaborative actions were taken for the efficient confrontation of PPV.

The importance of an international fruit tree virus and small fruit virus symposium for the progress of scientific knowledge in these fields of science, for solution of practical phytopathological problems, for fertile meetings and discussions, and for development of friendship and collaboration among scientists from all over the world is well known and cannot be overemphasized. The benefit of Greece, the hosting country, should also be recognized, and I am sure that by saying this I express the feelings of my Greek colleagues and the people involved in the production and protection of fruit tree and small fruit industry in Greece who appreciate our benefit from this opportunity.

Review editing of the papers submitted for this volume involved mainly uniformity of style, and did not interfere with the scientific subject itself which remains the responsibility of the authors. The authors are to be thanked for their prompt response to submit their contributions, and for their soft collaboration in the reviewing and retyping.

The Proceedings of the co-symposium on small fruit virus diseases are published as a separate volume of Acta Horticulturae (No. 236). Copies of both volumes, 235 and 236, will be mailed to the participants. Other copies may be ordered from the ISHS Secretariat, Dreijenplein 4, 6703 HB Wageningen, Netherlands.
P.E. Kyriakopoulou
Review Editor