PREFACE

This time we had only two general papers by invited speakers: one at the opening and one at the closing of the symposium. All other formal papers dealt with various aspects of virus identification, serology, electron microscopy, heat treatment and tissue culture and control of virus spread. Most papers were on applied virology; a few were of a more fundamental nature.

The meeting was attended by forty participants from Belgium, Denmark, Federal Republic of Germany, France, Italy, New Zealand, South Africa, United Kingdom, United States and the Netherlands.

The advantages and disadvantages were debated of different systems of publishing the proceedings and it was decided to publish the papers presented, either in detail or as an abstract, according to the recently adopted publishing policy of the ISHS. The author is thereby personally responsible for the final form of his text, and time-consuming editing is avoided. This procedure guarantees speedy publication, which is an important asset.

We hope, and trust, that the Fourth Symposium provided participants with opportunity for fruitful discussions and with suggestions and ideas for future work in this fascinating field.

F.A. Hakkaart


OPENING ADDRESS

Ladies and Gentlemen,

It is a pleasure to me to welcome you and especially the visitors from other countries on this symposium on behalf of Dr.De Bakker, Secretary General of the International Society for Horticultural Science.

Vous savez certainement que notre Société Internationale de la Science Horticole est une organisation bilingue et c'est pour cela et aussi pour les participants de l'expression française que je vous souhaite la bienvenue à ce symposium au nom de notre Secrétaire Général, Dr.De Bakker. Etant donné que le comité d'organisation a indiqué que la langue du symposium sera l'anglais je me confirmerai à cette indication et continuerai donc maintenant en anglais continental.

I have to apologize our secretary general for being absent as he returns today from a visit to South America. That is the reason why he requested me to replace him in his function of chairman of the organizing committee and to open your fourth symposium on Virus Diseases of Ornamental Plants.

Although I am a close collaborator to Dr.De Bakker, as well in the Ministry of Agriculture and Fisheries as in the secretariat of the ISHS, we had no contacts about this opening. I will take this opportunity to tell you something about the ISHS and about some activities of this organization.

At this time 45 countries are member of ISHS and represented in the Council, which meets once in two years. About 225 institutions, institutes, research stations or other bodies are affiliated member and finally we have about 1600 individual members in the world. I suppose that all participants of this symposium are member of ISHS. If unfortunately not so, you will certainly have the possibility to join the ISHS this week! The ISHS will welcome you heartily as a new member.

One of the activities of the Society is stimulating the organizing of symposia and publishing the proceedings of them.

We appreciate that the Commission for Plant Protection has agreed with the Working Group Virus Diseases of Ornamental Plants to plan this fourth symposium in the Netherlands. I can assure you that the executive committee of this symposium has prepared a programme which will give you the opportunity to combine lectures, discussions, meals and visits to some Research Stations with certainly healthy and I hope for you also virus diseased ornamentals.

As my formation at Wageningen made me a tropical agriculturist my original knowledge about virus diseases was limited to Tobacco Mosaic Virus and Pseudo Mosaic Virus. I have just seen in my old textbook the names of the research workers as Stanley 1935, Isolation of a cristalline protein possessing the properties of tobacco mosaic virus, and Thung 1937, Infective principle and plantcell in some virus diseases of the tobaccoplant. I have understood that these diseases provoked big losses of products in that time, like other virus diseases still do now.

Like in all fields of agricultural and horticultural research the research of viruses in plants has made big progress since the Thirties and especially since the work with the electron microscope has started.

In the proceedings of your third symposium of 1972 Dr.Lawson has asked between other questions how research workers recognize and anticipate the problems of tomorrow as we are trained for solving problems of today and not yet for finding problems of the future. I hope he has received some answers to his questions, but if not so, I will suggest him to repeat his question here which he mentioned in the very good looking Acta Horticulturae, number 36, or your 1972-symposium, of which Dr.Lawson was the organizer.

The publishing of proceedings of symposia is considered by us as the most important activity of the ISHS. From the start with Acta in 1963 to the end of 1972 the ISHS has published 26 numbers of Acta Horticulturae. Since 1973 up to now we have reached number 56 which will be published at the end of this month.

A more rapid publication is yet possible by using a new publishing system which is also used for your symposium. The main reason for this system is to obtain a considerable gain of time. Last year we have realised 3 Acta's following this system and I can assure you that if the papers and other needed information from the convener arrive at the secretariat in good shape, the Acta will be published in 2 or 3 months' time from the date of receiving the papers, made following the instructions of the writing-kit.

I am glad that your executive committee has agreed to publish the proceedings of your symposium and I am also happy that the lecturers have accepted to use the new publishing system by which final editing can be eliminated.

I am glad while the first idea was not to publish proceedings like the colleagues of the Working Group Virus Diseases of Vegetables have done. The ISHS prefers that you publish proceedings of a scientific meeting. The more important is publication in case of working groups like yours on Virus Diseases, while the subject is of real international importance and while different groups of research workers (vegetables, ornamentals, fruit trees) use the same or nearby the same techniques and have to solve identical problems. I came to this conclusion after reading the paper of Prof.Ronde Kristensen in Acta 36 and the paper of Dr.Bos in the last Chronica 15 of December 1975.

May I suggest you to think about a proposition to organize a meeting, conference, symposium or even congress for all the research workers concerned with virus diseases, and resistance breeding, for agricultural and horticultural crops from temperate, subtropical and tropical regions? I have heard that once earlier a Virus Congress has been organized in 1966. If the Plant Protection Commission takes over my suggestion they will certainly find a good date for such a meeting if the Working Groups of Fruit Tree Virus Diseases (since 1973), Vegetable Virus Diseases (since 1971) and Virus Diseases of Ornamental Plants (since 1964) agree on this idea.

As you know the ISHS has a free structure and it is not necessary to be a member of ISHS for being a member of a Working Group. But I think that being a member of a Working Group for some time it will be logically to become also a member of the ISHS. Unfortunately it does not always happen as expected and than we meet the situation that non-members have sometimes a decisive influence on the activities of a ISHS Working Group.

I will invite you to make every member of a Working Group a member of ISHS!

Prof.Ronde Kristensen has given some suggestions to improve international collaboration in the field of the study of virus diseases. I will remember you the following topics: list of indicator plants, list of antisera, list of identified viruses, list of distribution of virus diseases and some other items.

I can tell you that the secretariat is prepared to assist you in publishing the above mentioned lists, but it is also clear that the work has to be done by the research workers themselves. We need your assistance for such work, otherwise international cooperation will not lead to any results.

Ladies and Gentlemen, I know that you have today still 7 other persons on the programme, so I will now end with the hope that you will have good meetings and nice excursions. As the farmers urgently need rain it is difficult to wish you good weather. But with the wish for a good working and discussion climate I open this Fourth Symposium.