EUROPEAN AND MEDITERRANEAN PLANT PROTECTION ORGANIZATION
11-17010
Phytophthora ramorum
Extracts of reports of EPPO Meetings
As mentioned on the introductory section of the Web page on PRA documents, PRA documents are working documents which have usually been produced by an assessor whose opinion may have been commented during Panel meetings and comments have usually not been included in the PRA documents but are found in Panel meeting reports. This document consists of extracts of EPPO Meetings’ discussions on Pest Risk Analysis documents on the relevant pest. Discussions on Pest Specific Phytosanitary Requirements (PSPR)[1], have also been reported when relevant as they include elements on possible risk management options.
34th Meeting of the Panel on Phytosanitary Measures (Paris, 2002-01-22/25)
6. EPPO Alert List: annual review
6.3 PRAs proposed in support of retention on the Alert List
Phytophthora ramorum
The Panel was presented with a data sheet and a CSL summary pest risk assessment prepared by Mr Jones (GB). There was a very serious outbreak of the disease in California (US) on North American Quercus spp. (not known in Europe). Pathogenicity tests were being conducted on other species. Mr Horn explained that a fungus found on several occasions on rhododendron in the Netherlands was identical to the one attacking oak in the USA. It had also been found in 2001 in Germany on Viburnum, and surveys carried out on this genus in the Netherlands had detected infected plants. Action had been taken. Only one cultivar of Viburnum ´ bodnantense had been found infected. P. ramorum had probably occurred on rhododendron for several years in the Netherlands, but it had never been found on oak, or on any other species surrounding rhododendrons in public gardens. The situation was further complicated by the existence of mating types. Only the A1 mating type had been found in Europe, while all US isolates examined in Europe were A2 Though it was not sure that only A2 was present in the US, since A1 had not been searched for, such a situation would create an additional hazard for European oaks. He noted that climatic conditions in places where the pest occurred in the US were more humid than in Europe. Mr Bartlett said that surveys had been carried out in UK but the fungus had not been found. Mr Unger observed that the situation of P. ramorum in Europe still needed to be clarified. Surveys had been carried out in Germany on suspect plants, but results were not yet available. It was noted that the fungus had not been recorded as causing any significant damage in Europe and that, on the basis of European information, there would be little justification in taking measures against it as an A2 pest. Mr McNamara stressed that there was no doubt that the same fungus caused a very serious disease in USA, which could justify taking measures against it as an A1 pest. More information was clearly needed to reconcile these contradictory interpretations. Mr Horn said that a PRA was being done in the Netherlands, and a full pest risk assessment could probably be presented at the next meeting.
A full pest risk assessment report and a data sheet might be presented by the Netherlands at the next meeting.
35th meeting of the Panel on Phytosanitary Measures (Paris, 2003-01-21/24)
7. Candidates for the EPPO lists
7.11 Already considered at the last meeting
Phytophthora ramorum: The Panel was presented with a PRA and data sheet prepared by Mr Jones (GB) and a report of PRA prepared by Mr de Hoop (NL). Mr Horn reported that, in Europe, this pest had only be found in natural conditions on viburnum and rhododendron. There was currently no evidence that the European isolate could attack oak. Commission Decision no. 2002/757/EC stated provisional emergency phytosanitary measures. They aimed at preventing the spread and eradicating the European isolate, targeting plants for planting of rhododendron and viburnum, and at preventing the introduction of the non-European isolate. There were concerns that crosses between the non-European and the European isolate would result in further variability and damage. He reported that the EU intended to organize a workshop on P. ramorum to update the situation in Europe. Mr Bartlett noted that much research was being carried out on this pest, and especially on its possible other host plants. Surveys outside nurseries had begun and should give a clearer idea of the pest's distribution. One concern in UK was that it might attack Vaccinium. Mr Pfeilstetter reported that P. ramorum had been found during a survey in Germany in 2002 (38 cases on rhododendron and viburnum, and 2 findings in gardens). Inspections had mostly targeted nurseries (and not parks and gardens) and the pest might be present in other places. It had not been found on oak trees around nurseries. Mrs Perez noted that, in the absence of sufficient information on host plants, decision was not yet possible. Mrs Petter (Chairman) noted that, since the results of EU surveys would not be known before 2003-11, the current situation could be reported to the Working Party, and would be studied again at the next meeting. The Secretariat would write to countries to ask for further information. Mr Bartlett reported that detection of the pest during surveys might be influenced by many factors and Mrs Petter (Chairman) thought that this could be stressed at the Working Party. If instructions for surveys were available in some countries, it would be useful to provide guidance to the Working Party. In the meantime, the Secretariat would ensure that all EPPO members are well informed of the emergency measures of the EU for P. ramorum, as a possible basis for measures to be taken in other countries.
The situation of P. ramorum will be presented to the Working Party and will be further studied at the next meeting.
41st Meeting of the Working Party on Phytosanitary Regulations (Ukraine, 2003-06-25/30)
10. New pest situations
10.1 Phytophthora ramorum
Ms Petter (Chairman) explained that surveys on P. ramorum had been carried out in all EU countries, and that the pathogen had been found to be present in several EU countries, on ornamental shrubs but never on oak. The risk from European strains was not clearly established for the moment. Ms Vicinenza (USDA) said that the latest information on the situation in the USA could be found on the USDA web site. Mr Klag (NAPPO) noted that the list of hosts was frequently being extended. Ms Kunac (HR) reported that P. ramorum was considered to be absent in Croatia (no record). Mr Szabo (HU) said that surveys were carried out in Hungary following the EU protocol, and that no infections were found. Mr Husak (CZ) said that no survey had been carried out in Czechia but no finding was reported. Ms Romanova (LV) said that a survey was done some months ago in Latvia and nothing had been found.
Mr Unger (DE) informed the Working Party that the measures taken at EU level were under review. Surveys to detect the pest should be carried out in parks and gardens, and not only in nurseries. Mr Giltrap (GB) emphasized that P. ramorum was a major concern in the UK, where intensive surveys and research were in progress. The list of host-plants was increasing but no natural infection has been found on oak. There was concern that Rhododendron ponticum, which is widely naturalized in woodlands, could act as reservoir of infection for forest trees. However, though P. ramorum was detected in rhododendrons in parks near oaks, the oaks were not attacked. Inoculation of American and European strains to oak logs showed that European strains can be pathogenic to oak.
Mr Kroeker (SE) thought that it was not clear whether P. ramorum is really a new pest. The disease was highlighted when it was reported in California causing oak death, but had already been reported in Germany in 1997. He wondered whether climatic conditions in California were comparable with those in Europe. Mr van Opstal (NL) reported that the disease was now found in Canada where climatic conditions are different from those in California. Mr Kroeker (SE) thought it would be interesting to know if irrigation increased risk. Mr Unger (DE) stressed that specific surveys were needed to detect the pest, which is difficult to find. He thought that P. ramorum could be considered as a new pest, because no symptoms appeared before the 90’s. Mr van Opstal (NL) explained that Dutch nurseries had been surveyed since 1997. He stressed the importance of making surveys also in public parks because this would help to know more about the host species. Mr Sletten (NO) said that P. ramorum can readily be differentiated from other Phytophthora spp. and Mr Giltrap (GB) agreed that the distinctive morphology is new. It was difficult to evaluate the threat for the environment.
Ms Petter (Chairman) recalled that the pest was in any case on the EPPO Alert List and that the situation would be reviewed at the next Panel on Phytosanitary Measures.
36th meeting of the Panel on Phytosanitary Measures (Paris, EPPO headquarters, 2004-03-9/12)
8. Candidate Pests for EPPO listing
8.6 Update on the situation of Phytophthora ramorum
Mrs Petter (Chairman) reported that a questionnaire was sent in 2003 to gather information on the situation of this pest in member countries. Since then, many new host plants have been identified in the UK, including Quercus sp. and Fagus sylvatica. Mr Bartlett informed the Panel that a new PRA was available on the website of the Central Science Laboratory of the British NPPO, and that intensive surveys were being conducted in the UK. Mrs Petter (Chairman) asked if permanent measures were planned or if they were still emergency measures. Mr Horn stressed the necessity to know more on the presence of the pest in the natural environment. Mrs Petter (Chairman) concluded that it was too early to add P. ramorum to the EPPO list. She noted that a diagnostic protocol had been prepared and sent for country consultation, and hoped that it would be approved at the Working Party in 2004.
Mr Bartlett informed the Panel that a new species of Phytophthora was discovered during surveys and seemed more worrying than P. ramorum. It affects European beech (Fagus sylvatica) and rhododendron, and causes severe damage on beech. No scientific name has yet been published, but a description is available on the website of the Central Science Laboratory of the British NPPO.
The new species of Phytophthora attacking beech will be added to the Alert List.
42nd Meeting of the Working Party on Phytosanitary Regulations (Amman, 2004-06-22/25)
11. New pest situation
11.1 Phytophthora ramorum
Mrs Petter (Assistant Director) explained that P. ramorum had been added in the EPPO Alert List in 2001-01 after significant tree mortality had been observed on several oak species in California (US). Since then, the pest had been detected in Europe, but on other hosts (mainly Rhododendron and Viburnum). Mr Smith (Chairman) explained that the Secretariat had taken the decision to provide a more comprehensive reporting system on this disease, targeted at non-EU EPPO members, informing them of current EU measures and new information on the pathogen (similar to that provided on Diabrotica). Mr Giltrap (GB) commented that the situation on P. ramorum in the UK was rapidly developing. Updated information was available on the DEFRA website. He reported that a new damaging Phytophthora species had been detected on beech. He explained that Rhododendron plays a major role in dissemination of the pest. There is a programme in the UK to remove Rhododendron plants to protect other trees. Mr Unger (DE) informed the Working Party that there was an EU project on PRA for Phytophthora ramorum. He considered that there was no need for EPPO to duplicate this work. The Working Party considered that information on surveillance procedures would be interesting for EPPO members.
37th meeting of the Panel on Phytosanitary Measures (Paris, 2005-03-08/11)
8 Candidate Pests for EPPO listing
8.3 Specific case
8.3.1 Phytophthora ramorum
No new information was available for the Panel meeting but it was stressed that the EPPO Conference on Conference on Phytophthora ramorum and other forest pests will provide the opportunity for further exchange on the status of this pest in the region .
38th meeting of the Panel on Phytosanitary Measures
Paris, 2006-03-06/08
5. Candidate pests to be recommended for regulation by EPPO member countries
5.2 Review of PRA prepared by the Panel for PRA: Phytophthora lateralis
· Measures identified for plants for planting of susceptible plants (i.e. Pest-free place of production and buffer zone): The Panel did not understood why a buffer zone was required and that such buffer zone was not required for Phytophthora ramorum in the current EU requirements. The EPPO Secretariat explained that it resulted from the capacity of the pest to be spread by running water (which is different from P. ramorum). If the place of production is in a contaminated area, the risk of contamination with water is important. Some Panel members considered that a pest-free place of production without a buffer zone may be established provided that contamination through running water is prevented by exclusion measures.
40th meeting of the Panel on Phytosanitary Measures
6. Alert List
6.1 Annual review
· Phytophthora ramorum. Ms Pacheco reported that the EU PRA is to be finished in 2008-10. The Panel agreed to maintain P. ramorum on the Alert List for an extra year.
41st meeting of the Panel on Phytosanitary Measures (Paris, 2009-02-16/20)