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The History of the European Whitefly Studies Network Dr Ian D. Bedford (EWSN coordinator 1999 – 2007) In order to relate the story of EWSN, the European Whitefly Studies Network, we need to go back twenty five years to 1988. At that time, I had just started a new job at the John Innes Centre, as manager of the Insectary. The insectary comprised of a quarantined building that housed a number of different Hemipteran species that had been collected from around the world. These species were all important plant pests as they were the vectors of specific plant viruses, in particular the Geminiviridae family, and were the focus of many research projects within JIC’s department of Virology. Besides maintaining the insect colonies under a government Plant Health license, my work involved designing and undertaking the bioassays for the various research programmes. One insect species in the collection was of particular interest to me. It was a small colony of the Tobacco Whitefly Bemisia tabaci, that had been brought back from Turkey by a colleague in 1981 and was being maintained on cotton plants. Despite B. tabaci being recognised as the vector of most dicotyledonous-infecting geminiviruses, no one at JIC was working with the whitefly and, to my disappointment, no one had any of the viruses it was associated with. However, in 1990 I was contacted by Dr Phil Jones from Rothamsted Research Institute, who had just returned from the Republic of Yemen. Phil had brought back samples of three crops that were being decimated by what was assumed to be whitefly-transmitted geminiviruses; tomato, tobacco and watermelon, and I was asked if I could try and transmit the viruses with my B. tabaci colony. To cut a long story short, I devised a simple in vitro system for enabling the whitefly to acquire and transmit all three of the viruses and a collaborative research project to characterise the viruses was started. I was also lucky enough to find a few whitefly larvae on the plant material that Phil had given me and so I was able to start a colony of Yemen B. tabaci. Having now got a reliable system in place at JIC for whitefly transmission of geminiviruses a number of whitefly-related projects were started at JIC and viruses and B. tabaci were acquired from many different locations worldwide. Around this time, B. tabaci had starting to become a serious problem in a number of places around the world. For example, the Californian winter vegetable crops in 1991 suffered huge losses whilst crops throughout the Mediterranean basin began to succumb to whitefly-transmitted viruses. Even the UK had become concerned about the potential threat from B. tabaci to the horticultural industry as increasing numbers of whitefly were being found on ornamental plants such as gerbera and poinsettia.


In the US, the whitefly-related crop losses had triggered research into addressing the new whitefly problems. Historically, B. tabaci had been known in the New World for many years but was only a sporadic and controllable plant pest, so it was important to understand why this species had so rapidly increased in pest status. Before long, biological and biochemical differences were being found between different populations of B. tabaci in the US. Populations where problems were occurring were also found to be causing phytotoxic responses in certain plant species such as ‘Silverleaf’ in cucurbits and ‘White Streak’ of cole crops. This was not the case for the B. tabaci populations where crop problems were not occurring. Further investigations compared non-specific esterase banding patterns between the different populations and revealed that two distinct whitefly groups were present. These were named B. tabaci Biotype A and B. tabaci Biotype B. The latter being the whitefly from the problematic populations. Prof. Judy Brown from the University of Arizona was leading many of the early US studies, so I and colleagues at Rothamsted Research were able to collaborate with Judy on the biological studies and the esterase analysis respectively. Whilst all this work progressed, JIC’s insectary had been steadily expanding its collection of different whitefly populations from around the world. Eighteen different colonies were now being maintained which provided a great opportunity to expand our collaborative projects and investigate the much wider global situation with B. tabaci. Consequently, B. tabaci Biotype B, was identified in locations on all continents and was confirmed as being the ‘biotype’ linked to the global trade in certain ornamental plants. The work also revealed that distinct, non-B biotype populations were present in different geographic locations. These were subsequently allocated a specific biotype identification based initially on a distinct non-specific esterase banding pattern. By 1995, whitefly-transmitted viruses were present in crops throughout the Mediterranean countries and had spread to all tomato growing regions of southern and eastern Spain. In addition, both B biotype and Q biotypes (assumed to be the native Mediterranean strain), were being found. To try and direct our research capabilities on the European issues, I set up a small whitefly team within the UK. The team comprised of Dr Michael de Courcy Williams (HRI), Drs Matt Cahill & Ian Denholm (Rothamsted), Dr Derek Morgan (CSL), Dr Jon Martin (NHM) and myself (JIC) and provided expertise in the key areas of whitefly research; virus epidemiology; virus & vector characterisation; insecticide resistance; biological control; modelling & risk assessment and decision support. With grants from the British Council and Royal Society we were able to fund the UK team to visit southern Spain and establish links with researchers throughout the region. This resulted in the formation of the UK – Spanish Whitefly Network and involved Researchers from CIDH, La Mojonera, Almeria (Dr Isabel-Maria Cuardado Gomez, Dr Jose Enrique Gonzales, Dr Dirk Janssen & Dr Maria Dolores Rodriquez), University of Malaga (Dr Eduardo Bejarano, Dr Enrique Moriones & Dr Jesus Nevas) and CIDA, La Alberca, Murcia (Dr Jose Luis Cenis Anadon). Soon after, the UK-Spanish Whitefly Network, expanded into the Canary Islands when whitefly transmitted viruses started to appear in their tomato crops. This involved researchers at the ICIA La Laguna, Tenerife (Dr Estrella Hernandez-Suarez and Dr Aurelio Carnero).


The UK-Spanish whitefly network was highly successful in providing all of its members with opportunities to set up collaborative projects and to monitor the distribution and impact of the associated viruses. However, the problems continued to spread into other countries at an alarming rate. Virus outbreaks were becoming more severe and insecticide resistance was occurring. Reports of whitefly-transmitted viruses appearing in southern France in 1998 demonstrated that crops within the more temperate European regions were also at risk.

Members of the UK - Spanish whitefly network discuss the whitefly issues amongst greenhouses in Almeria Spain.

It became clear that we needed to expand our whitefly network so that it included researchers from the other affected countries within Europe and also involved crop protection companies. So, late one evening in a favourite tapas bar in Almeria called ‘the Casa Puga’, we decided that we should try for an EC Concerted Action grant through the FAIR 6 programme. The cerveza must have been particularly strong that night, since I apparently volunteered to write the proposal with only one month to submit! Over the following weeks, with invaluable help from Michael de Courcy Williams, the proposal was written, submitted and then successfully awarded as a 2 year EC-funded concerted action (FAIRCT98-4303), to begin on March 1st 1999.

The concerted action enabled us to set up ‘The European Whitefly Studies Network’ (EWSN) , an interactive network of researchers from across Europe, encompassing a wide range of skills and experiences with whiteflies and their associated viruses. Our main objectives were to gain a better understanding of the current whitefly problems within Europe and to identify research priorities by establishing and formalising links between European whitefly researchers, collating information on European whitefly related problems and current research, and improving the exchange of information between researchers.


EWSN’s official partners were:

Annie Enkegaard (Danish Institute of Plant and Soil Sciences. Denmark) Francois Bertaux (Laboratoire National de la Protection des Végétaux. France) Jean-Claude Onillion (Laboratoire de Biologie des Invertébrés. France) Thomas Frischmuth (Biologisches Institut Universitaet Stuttgart. Germany) Stephan Winter (DSMZ Germany) Kostas Bourtzis (F.O.R.TH. Greece) Nikos Katis (Aristotle Faculty of Agriculture. Greece) Dan Gerling (Tel Aviv University. Israel) Gian Paolo Accotto (Istituto di Fitovirologia Applicata del CNR. Italy) Maurizio Calvitti (ENEA Italy) Marco Mosti (Bioplanet Cesena. Italy) Antonio M.F. Aguiar (Laboratorio Agricola da Madeira. Madeira) Nina Svae Johansen (Norwegian Crop Protection Institute. Norway) Diamantina Louro (DGPC. Portugal Nigel Dungey (Hazlewood VHB. Portugal) Carmelo Rapisada (Scienze e Teconologie fitosanitarie Università degli Studi. Sicily) Vicente Medina Piles (IRTA. Spain) Francisco J. Beitia Crespo (CIT-INIA. Spain) Christina Castane (EAIRTA Spain) Federico Garcia Jimenez (Syngenta Bioline. Spain) Elisabeth Gripwall (Swedish University of Agricultural Sciencies. Sweden) Peter Wyss (Novartis Basle. Switzerland) Aurelio Carnero-Hernandez (ICIA Tenerife) Joanne FRANSEN (Research Station for Floriculture. The Netherlands) Ian Bedford (JIC. UK) Michael De Courcy Williams (HRI. UK) Ian Denholm (Rothamstead. UK) Derek Morgan (Central Science Laboratories. UK)

In addition to the primary objectives, EWSN also aimed to improve the transfer of technology across Europe, provide training in the various disciplines and work towards a standardisation of all the major techniques involved in whitefly research. It was hoped that information and knowledge exchange through EWSN would then underpin development of effective whitefly control methods that in turn would help address the whitefly-related crop problems and reduce insecticide inputs. By establishing links between researchers and the technical advisors for the growers, EWSN was also able to deal with the fundamental problems of implementing changes within long established growing practices. Information gained through the network would also help to risk assess the potentials of whitefly pest species and associated plant viruses that were already within southern Europe, spreading into northern Europe and into countries that were maintaining whitefly exclusion zones.


EWSN encompassed five key disciplines of whitefly research; Virology, Epidemiology, Faunistics & Systematics, Natural Enemies and Pest Management. A working group was set up for each discipline and EWSN participants were allocated to the group(s) that most matched their particular skills, experiences and interests. Over the two years of the concerted action, working group meetings were planned so participants could review and standardise the techniques that were being used within the particular areas of whitefly research. Two major workshops were also planned during the programme. One of the key tasks of EWSN was to collate and disseminate information on European whitefly issues, and this was to be achieved through regular newsletters and a website. For this task, we employed Mr David Oliver as EWSN’s Research Facilitator where his skills in graphic design and website management were to be instrumental in promoting and reporting EWSN’s activities. EWSN’s first workshop for its 28 official members, was planned for May 3rd-7th 1999, at the John Innes Centre in Norwich UK. However, the event had also attracted interest from crop protection companies that were involved in whitefly control. Offers of commercial sponsorship in exchange for participation in the workshop were gratefully accepted as it enabled us to increase the number of participants in EWSN and expand its activities.

Delegates at EWSN's first workshop held at the John Innes Centre, Norwich UK

During EWSN’s first year, the number of participants in EWSN increased to over 70! We were also able to organise a new workshop in the Canary Islands (November 14th -21st 1999), to review the escalation of whitefly and virus problems within crops across the islands. Hosted by Dr Estrella Hernandez-Suarez and Dr Aurelio Carnero-Hernandez, a delegation of 18 EWSN members visited the affected sites on Tenerife, Gran Canaria, La Palma and La Gomera, held question and answer sessions with growers and collected samples of whiteflies and infected crops. These were taken back for study within the participant’s respective labs across Europe. Pest and pathogens were characterised and their locations mapped. The results and advice on how to reduce the problems were then published in a booklet that was distributed to the Canary Island growers.


The Canary Island workshop delegates

EWSN’s three working group meetings proved to be a great success, enabling participants to present and discuss their current research and to determine how methodologies could be improved and standardised for the different disciplines . EWSN’s virologists met in Stuttgart University (March 14th-15th 2000), to review the whiteflytransmitted viruses that were now present in Europe and related research.

The Virology & Epidemiology working group

The second working group meeting ‘Characterisation and Identification of Whitefly Species, Biotypes and Natural Enemies’ was held at the John Innes Centre (May 18 – 21st 2000) for EWSN’s taxonomists and those involved in Faunistics and Systematics. This meeting successfully established collaborative links between traditional taxonomists and the researchers who were using the relatively new molecular techniques.

The Faunistics & Systematics Working Group


EWSN’s third working group meeting was held at Koppert’s facilities in Aguilas Spain (7th – 9th December 2000) to review whitefly-related Plant Protection and IPM within Europe. Over 40 participants were able to attend and also partake in field trips to see the affected crops within the region.

The Plant Protection & IPM working group

From all of the working group meetings, information sheets, identification guides and technical protocol were produced for a resource pack that was later distributed to all EWSN members. EWSN held its final workshop as an EC-funded concerted action, at the University of Catania, Sicily (February 26th 2001), hosted by Professor Carmelo Rapisarda.

Prof. Carmelo Rapisarda

Over 70 members attended and reviewed the network’s activities over the previous 2 years. Members also voted to continue with EWSN for as long as possible after assurances were received for continued financial support from its commercial associates and sponsors. The continuation of EWSN after the EC concerted action grant ended in March 2001, would not have been possible without the support of Syngenta, Biobest, Bayer, Koppert, PlanProtect, EcoSpray, CertisBCP, Bioplanet, Cal Agri Products, IRAC, Pocket Diagnostics, Oecos, Stan Brouard Ltd., and the John & Pamela Salter Charitable Trust. As already mentioned, the success of EWSN in acquiring additional funding had meant that further meetings and activities could be planned and undertaken. So, during the planning meeting for


EWSN’s second and final workshop in Sicily, Prof. Rapisarda made the unexpected suggestion that we should consider adding on a European whitefly symposium! Through determination and the phenomenal efforts of Prof. Rapisarda to gain support from his local government, the 1st European Whitefly Symposium (EWS1) became a reality and went ahead in Ragusa (February 27th – March 3rd 2001). The astonishing baroque architecture of this UNESCO World Heritage town created a truly unforgettable location for EWSN’s inaugural European whitefly symposium. Over 200 delegates from across the world attended the four day event at which 113 presentations were made. Prof. Rapisarda and his team of local organisers had also arranged a magnificent itinerary of technical excursions and social events that helped to forge many new friendships within the whitefly fraternity. Over the following years, EWSN membership continued to grow. By 2003, around 150 members across the world were actively exchanging information on whitefly-related issues which was being disseminated by EWSN through its newsletters and website. Notifications of new problems, new products and new research were rapidly made available to the EWSN members. In 2004, EWSN’s 6th year, it was decided that a second European Whitefly Symposium (EWS2) should be arranged. Whitefly outbreaks were now regularly occurring within the more temperate European countries, so Croatia was suggested as a suitable host country. Following discussions with Dr Katja Zanic and Mrs Helenka Aras from the Institute for Adriatic Crops and Karst Reclamation, the venue was chosen at the Hotel Croatia, Cavtat (October 5th – 9th 2004). This stunningly beautiful location provided an ideal opportunity for the 170 delegates to review the current global whitefly issues and also learn of those starting to emerge in new areas such as Croatia and along the Adriatic Coast.

Mrs Helenka Aras (left) and Dr Katja Zanic (right)

Dr Zanic and her organising team ensured that the symposium was an extraordinary success and that all of the delegates experienced the generous hospitality of their Croatian hosts. One of the social highlights was when a flotilla of traditional boats took the delegates across the Neretva river valley.


Delegates travel along the Neretva river during an EWS2 technical excursion

The success of both EWS1 & EWS2 clearly demonstrated the international importance of whiteflies as plant pests and that there remained a need to continue providing a platform for collating and disseminating information on related research, management and control throughout the world. EWSN had demonstrated how this could be achieved on a European-wide level and had already started to work on an International Whitefly Studies Network that involved groups within the Americas, Asia, Africa and Australasia. However, for EWSN to continue being coordinated from the John Innes Centre, it had to remain financially independent by acquiring external funds to cover all costs. This included the employment costs of its Research Facilitator, Mr David Oliver and the Events Organiser, Mrs Liz Robertson. By 2007 and with recessions looming, we unfortunately failed to meet the financial requirements and the EWSN office was closed. The closure of EWSN also meant that we could no longer be involved in helping to organise the third European Whitefly Symposium (EWS3), Almeria Spain (October 20th – 24th 2008) which was to be hosted by Dr Dirk Janssen (IFAPA). Thankfully, Dr Janssen and his colleagues were able to continue with their plans and they successfully organised and held EWS3 as originally planned. Having had to end the coordination of EWSN from the John Innes Centre after 8 successful years, was deeply regretful. Since its initiation in March 1999, EWSN had succeeded in delivering all of its original objectives and had continued providing a forum for anyone involved in whitefly study and control to share and disseminate their research and information. In addition, one of the most important achievements of EWSN was to demonstrate just how valuable it was to build collaborations and friendships into science programmes. The people I met and worked with through EWSN over my eight years of coordinating the network, are beyond doubt some of the most wonderful people I have ever had the pleasure of knowing. I am very proud to have made friends with so many truly great people and to have shared such memorable experiences.


I am also immensely happy to see that EWSN’s past achievements have helped to sustain a proactive whitefly fraternity through to the present day and that the first International Whitefly Symposium has now been organised for Kolymbari Crete (May 20th – 24th 2013). I congratulate the organisers, Dr Emmanouil Roditakis, Dr Anastasia Tsagkarakou and Dr John Vontas and wish every success for the event. I am sure that the location for this first international event would have met with approval from Gennadius! With kindest regards to one and all. Ian

The History of the European Whitefly Studies Network  

Dr Ian D. Bedford (EWSN coordinator 1999 – 2007)

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