PREFACE

PREFACE
This volume of Acta Horticulturae is the Proceedings of the Ninth International Workshop on Fire Blight. Invited and keynote speakers and selected authors of offered oral papers and posters had the opportunity to submit their manuscripts for publication in this volume of the series Acta Horticulturae.
Submitted manuscripts were reviewed by the Editors and amended according to the referee suggestions prior to acceptance.
The ISHS acknowledges the cooperation received from the Editors on reviewing the manuscripts which was a significant contribution to the overall quality of the publication.

The ISHS Board of Directors

CHAIRMAN’S REPORT
The IX International Workshop on Fire Blight was held at the War Memorial Conference Centre, Napier, Hawke’s Bay, New Zealand from 8 – 12 October 2001. The workshop was organised by The Horticulture and Food Research Institute of New Zealand (HortResearch) and The New Zealand Society for Horticultural Science.
About 120 participants from 22 countries attended the workshop. A total of 103 papers were presented of which 40 were oral presentations and 63 were posters. There were five main sessions and an open forum.

SPREAD AND ECONOMICS
The session was chaired by Jean-Pierre Paulin (INRA – France) who introduced presentations on the present world-wide distribution of fire blight followed by updates on the disease on a number of hosts in various countries around the world including Spain, Iran, Israel, The Netherlands and the Republic of Moldova. Also in the session were papers discussing the role of honey bees in spreading Erwinia amylovora and a re-examination of fire blight spread and incidence in England providing new evidence on the mode of entry into that country. The standardisation of diagnostic protocols for the pathogen in the European Union was also discussed.

Epidemiology and Prediction
This session was chaired by Gary Lightner (USA) who paid tribute to the life of the late Paul Steiner who played such an important role in developing forecasting systems such as Maryblyt^TM for the prediction of fire blight as an aid to growers in their battle against the disease.
Papers in this session dealt with the detailed epidemiology of the disease and examined a number of interesting new tools such as fluorescence imaging and quantitative PCR methods for investigation of the population dynamics and monitoring the pathogen in association with plant material. The use of epidemiological information was discussed in relation to the development of forecasting models for optimisation of both chemical and biological control strategies.
Immediately after this session Gary Lightner facilitated a discussion on technical issues associated with the export of fruit to countries without fire blight. This sensitive topic generated much discussion on whether or not exported fruit pose a threat and whether or not fruit are in fact a vector of the pathogen and if so, are fruit part of the pathway for the possible introduction and establishment of the disease in fire blight-free countries. Although viewpoints of workshop participants differed fruit has never been proven to cause outbreaks of the disease.

Fire Blight Management
The session chaired by Ken Johnson (Oregon State University) included papers on biological and chemical control of fire blight. Results on the development, commercialisation and performance of biological control agents were presented from Italy, US, Germany, and New Zealand, involving gibberellin inhibitors, systemic acquired resistance, bacteriocins, non-pathogenic bacteria, and plant extracts. Environmental factors affecting the interrelationships between plant growth and the biological control strategies were also discussed. Other papers in the session dealt with mechanisms of action of biological control agents in the control of fire blight, the design of experimental protocols for testing of control agents under near natural conditions, and integrated disease management involving a range of biological and chemical control agents.

Plant-Based Strategies for Control
The session chaired by Jay Norelli (Appalachian Fruit Research Station, US) focused on host responses to infection and their manipulation for enhanced resistance, conventional plant breeding for enhanced resistance, and enhancing resistance by transgenic expression of anti-microbial gene products. The session included two discussion periods looking at future potential in these areas and the advantages and disadvantages of the various approaches to manipulation of host response and to enhancing plant resistance.

Biochemistry and Molecular Advances
The session chaired by Joel Vanneste (HortResearch, New Zealand) included papers on the use of molecular tools for the differentiation of Erwinia amylovora strains. Of particular note was the molecular comparison and differentiation of Erwinia strains causing fire blight and Asian pear blight. Other papers in the session focused on pathogen biochemistry and the expression proteins in the bacterium. In papers focusing on the plant, the mechanisms underlying the disease and resistance responses in fire blight host plants, and the role of the pathogenicity factors in the induction of defence mechanisms in susceptible hosts were discussed.

Open Forum
The research programme concluded with an open forum and panel discussion facilitated by Herb Aldwinckle (Cornell University, United States). The development of a research and management strategy for fire blight to the year 2010 was the initial topic. However, emphasis was put on research advances and issues as integrated control measures for the disease are sought. The panel discussion, which included each of the session chairpersons, was a departure from the format of previous fire blight workshops and it proved to make a valuable contribution to this the IX International Workshop on Fire Blight.
The workshop participants and partners were offered a pre-workshop tour from Auckland to Napier visiting a rootstock nursery and a kiwifruit research station in the Bay of Plenty. The mid-workshop tour included a visit to a state-of-the-art packhouse, orchards, and the Hawke’s Bay Research Centre where research is focussed on pipfruit, stonefruit, and grapes.

Business Meeting
An ISHS business meeting was held towards the end of the workshop. Dr. Chris Hale from HortResearch, New Zealand, was elected as the new Chairman of the ISHS Fire Blight Working Group. Dr Carlo Bazzi, University of Bologna, Italy will host the next workshop in 2004.
In summary the workshop was very successful and allowed the participants to exchange knowledge and experiences in the intriguing area of fire blight research, to maintain old and make new acquaintances, and to visit the Southern Hemisphere for the first time in the Fire Blight Workshop series. The organising committee would like to thank those who contributed to the success of the workshop, particularly those involved in administration and sponsorship.

OPENING ADDRESS
It is an honour and great pleasure to welcome you to the 9^th International Workshop on Fire Blight. This workshop was organised under the auspices of the Fire Blight Working Group of the International Society for Horticultural Sciences (ISHS), the New Zealand Society for Horticultural Science (NZSHS) and HortResearch (The Horticulture and Food Research Institute of New Zealand Ltd).
First of all, we would like to express our sincere thanks to Dr. Chris Hale and his Colleagues who have planned and worked diligently over the last three years for the organisation of this Workshop here in Napier, New Zealand.
We also extend our thanks to ISHS, NZSHS, HortResearch, GroChem, McGrath’s Nurseries, OnCall Conference Management and War Memorial Centre, Napier for their helpful support and cooperation in organising the Workshop.
In 2000, Erwinia amylovora caused severe fire blight outbreaks on apple, pear and ornamental plants in many different parts of the world. The challenge to manage fire blight effectively at the local and international levels still continues. Risk assessment studies addressing the importation of apples and pears into fire blight free countries have gained importance. Studying fire blight biology as separate phases, such as blossom blight, shoot blight, rootstock blight and trauma blight has resulted in a better understanding of fire blight epidemiology, and the understanding of the interactions among those phases will lead to new knowledge on this very complicated disease. Much progress has been made in the three years since our last workshop in Kusadasi, Turkey. We are confident that the presentations to be made at this workshop on plant breeding, biotechnology, molecular biology and integrated disease management will ultimately lead to the more effective management of fire blight and reduced economic losses of the fruit and ornamental industries worldwide. This 9^th International Workshop continues the tradition that began 23 years ago in The Netherlands to provide a forum for all fire blight workers a chance to learn and discuss the latest developments in all aspects of fire blight research.
Keeping with the tradition of our group, we will discuss the location of the next Workshop in 2004 at our business meeting on Thursday. There is already one proposal to organise the next workshop in the USA by USDA/ARS Appalachian Fruit Research Station.

We wish you all a very successful 9^th Workshop and pleasant stay in New Zealand.

M. Timur Momol and Hikmet Saygili, Co-Chairmen
Fire Blight Working Group of ISHS

REPORT OF THE BUSINESS MEETING
The Business Meeting of the ISHS Working Group on Fire Blight was held on 11 October 2001 in conjunction with the 9^th International Workshop on Fire Blight (IWFB) at the War Memorial Conference Centre, Napier, New Zealand.
The meeting began with opening remarks by the Co-Chairman, Professor Hikmet Saygili, and minutes were recorded by the Secretary, Dr Chris Hale.
Delegations from the United States, Italy and Switzerland offered to host the next Workshop in 2004. Dr Robin Mitchell, Dr Joel Vanneste and Mr Robert Taylor were appointed as vote counters. Delegates attending the Business Meeting then voted for the site of the next workshop. Following the vote count, the results were announced that Italy would be the venue for the 10^th International Workshop on Fire Blight.
The Chairman and Secretary of the ISHS Working Group on Fire Blight were elected for the next three-year period. Dr Chris Hale would serve as Chairman and Dr Carlo Bazzi of Italy as Secretary of the Working Group on Fire Blight.
Dr Bazzi will organise the next workshop in Italy in 2004. The decision on the venue for the 2007 workshop will be determined at the 10^th International Workshop on Fire Blight.
Dr. Chris Hale
Secretary of the ISHS Working Group on Fire Blight