For. Snow Landsc. Res. 76, 3: 402–404 (2001)
Plant health and quarantine regulations of the European Union for Cryphonectria parasitica
Dieter Seemann
Forest Research Institute of Baden-Wuerttemberg, Departement of Forest Protection, Wonnhaldestr. 4, D 79100 Freiburg, Germany
seemann@fva.bwl.de
Abstract [Review article]
The quarantine regulations for Cryphonectria parasiticaas prescribed by the European Union are listed and discussed. Special emphasis is given to the diversity of vegetative compatibility (vc) types of the pathogen within Europe. An increase in vc types in a region may potentially hinder the success ful spread of hypovirulence.
Keywords: chestnut blight, quarantine regulations, Castanea sativa
1 Introduction
Cryphonectria parasitica(Murr.) Barr is a quarantine disease. Quarantine regulations are meant to prevent the dangerous pathogen from further spreading. These regulations make it an obligation for any country to eradicate harmful organisms and, where this is not possible, to prevent their further spread.
C. parasiticawas first reported in Italy in 1938. Since then the pathogen has affected nearly every area with Castanea Mill. in Europe. The only areas it has not yet reached are the outer chestnut areas like the United Kingdom. In recently affected regions like the southwest of Germany the infected areas are comparably small. In areas infected for a longer time there are only a few chestnut stands that are free from the disease. The fungus has numerous veg- etative compatibility (vc) types. The types are unevenly distributed in Europe. In a newly- infected area, only one type appears first. Later other types appear. The spread of the fungus may be delayed by the occurence of hypovirulence, especially in regions with older infection.
Hypovirulence occurs mostly with the vc type that appeared first in the region. Reduced viru lence retards the spreading of the pathogen. However, any newly-established vc type starts another phase of aggressive spread. As hypovirulence is transmitted only within the same vc type, spread of the fungus slows down only when the new vc type shows hypo - virulence. The distribution of C. parasiticavc types and hypvirulence in Europe is sum- marised by ROBINand HEINIGER(this volume).
2 Plant protection organizations
To prevent the introduction and spread of pests and diseases of plants and plant products, the International Plant Protection Convention (IPPC) was established under the Food and Agricultural Organization (FAO) in 1951. The IPPC has been ratified by 113 governments to date. When the World Trade Organization (WTO) was established, the Agreement on Sanitary and Phytosanitary Measures (SPS Agreement) also entered into force. In general, this agreement specifies that any plant health measures must be based on scientific risk assessment so that they do not result in unnecessary barriers to international trade. The FAO/IPPC standards exert an influence on the regulations established in Europe. According to the IPPC, the European and Mediterranean Plant Protection Organization (EPPO) is the regional plant protection organization of Europe. Today the EPPO has 43 member states. Its
403 For. Snow Landsc. Res. 76, 3 (2001)
objectives are to develop an international strategy for preventing the introduction and spread of harmful organisms, to harmonise plant protection action and to promote new pest control methods. Its members within the various organizational structures are government representatives, plant health experts and scientists. The experts are appointed to panels of working parties and develop regional (European) standards of phytosanitary measures. The member governments are obliged to keep to the standards within their countries. They put this obligation into practice through their national plant protection services. Furthermore, all member governments have to notify the EPPO about the occurrence of harmful quaran- tine organisms.
Quarantine organisms are listed in EPPO A1 and A2 quarantine lists. The organisms specified in the A1 list are not present in Europe. The organisms specified in the A2 list occur in some European countries. C. parasiticais an A2 pest. For each of the pests, EPPO elaborates specific plant health measures. The EPPO Standard PM 2 “Specific Quarantine Requirements” (SQR’s) for C. parasitica is available from the electronic documentation service of the EPPO (UNGERet al.1998).
3 Legal regulations of the European Union
Quarantine regulations for the European Union are based on the EC Council Directive 2000/29/EC of 8thMay 2000 (former 77/93/EEC). It has to be transposed into national law. In Germany, the corresponding law is the Plant Health Order in the revised version as announced on 3rdApril 2000. Supervision of this and other orders is assigned to the national plant protection organizations. Annex V of Directive 2000/29/EC specifies the plants, plant products and other objects which require inspection and a certificate or plant passport.
Plants, plant products and other objects that are moved within an EU Member State or to another Member State require a plant passport and have to satisfy certain plant health requirements.
Requirements for C. parasiticarefer to the following plants and plant products:
– wood with bark of Castanea sativa(Mill.);
– isolated bark of Castanea sativa(Mill.);
– plants of Castanea sativa(Mill.) and Quercusspp.
A plant passport allowing plants to be moved will be issued:
– for plants or plant products originating in areas known to be free from the pest.
– for chestnut wood originating in areas not known to be free from the pest, only on con - dition that it is stripped of its bark, even if the wood is free from infection. Infected wood must not leave the area, even without bark.
– for isolated bark of Castanea sativaonly if it originates from areas known to be free from infection or, if it originates in an infected area, it may only leave the area after producing evidence of disinfection. As there is no method of disinfection yet known, this means bark must not leave an infected area.
– for plants of Castaneaand Quercusthat originate in an infected area only if the plant pro- tection service guarantees that no C. parasiticahas been found at the place of production and in its immediate vicinity since the beginning of the last complete cycle of vegetation.
Relevant plants and plant products from EU third countries require plant health certificates and inspection and have to satisfy further special requirements equivalent to the require- ments for EU products.
404 Dieter Seemann
4 Infected areas
In regions where C. parasiticainfection has been found, it is necessary to identify affected areas or stands. Identification requires monitoring. This is the only way to satisfy the above mentioned requirements. However, it is difficult to find clear rules for identifying affected areas as affected since the distribution of sweet chestnut within the EU varies greatly as does the occurence of C. parasitica. In newly infected areas and infected areas far apart from each other as in Germany, it is possible to identify 20 ha areas (SEEMANNet al.2001). In countries where entire landscapes are infected, accordingly larger areas have to be identified.
Identification is carried out by the national plant protection organizations.
5 Recommendations
Quarantine regulations apply to the entire EU region. As C. parasiticahas a specific patho- genicity, it is not enough to prevent the spread to areas free from it. It is as well important to prevent the spread of the various vc types within an area and to stop further vc types entering.
This is all the more important because the introduction of new vc types ruins the very cost- intensive efforts to establish artificial hypovirulence in infected stands. The various vc types are very unevenly distributed over Europe and hypovirulence has not yet been found for all vc types. Heavy infection within an area with new vc types may prevent the spread of natural or artificial hypovirulence. Therefore, to prevent the introduction of new vc types that may jeopardise the effect of hypovirulence, the above-mentioned quarantine measures should also be applied to larger infected areas.
Acknowledgement
The author wishes to express his appreciation for assistance given by R. Voigt and S. von Norsinski, Federal Biological Research Center for Agricultural and Forestry (BBA), Braun - schweig, Germany.
6 References
ROBIN, C.; HEINIGER, U., 2001: Chestnut blight in Europe: Diversity of Cryphonectria parasitica, hypovirulence and biocontrol. For. Snow Landsc. Res. 76, 3: 361–367.
SEEMANN, D.; BOUFFIER, V.; KEHR, R.; WULF, A.; SCHRÖDER, T.; UNGER; J., 2001: Die Ess - kastanie (Castanea sativa Mill.) in Deutschland und ihre Gefährdung durch den Kastanien - rindenkrebs (Cryphonectria parasitica [Murrill] Barr). Nachr.bl. Dtsch. Pflanzen schutzd. 53:
49–60.
UNGER, J.G.; MOTTE, G.; VOIGT, R., 1998: Entwicklung von Pflanzenquarantäne und Regelungen zur Pflanzengesundheit und deren staatliche Organisation in Deutschland. Mitt. Biol.
Bundesanst. Land- Forstwirtsch., Berl.-Dahl. 348: 89–114.
Further information:
EPPO Summaries of Phytosanitary regulations of 1.1. 2001
EPPO electronic documentation service: Cryphonectria parasitica PM 2/69(3) Council directive 2000/29 EG, 3. Apr. 2000 and other specific control directives BBA: http://www.bba.de
EPPO: http://www.eppo.org IPPC: http://www.fao.org
Accepted 25.2.02
