Bulletin OEPP/EPPO Bulletin (2018) 48 (3), 503–515 ISSN 0250-8052. DOI: 10.1111/epp.12505 European and Mediterranean Plant Protection Organization Organisation Europe´enne et Me´diterrane´enne pour la Protection des Plantes PM 9/1 (6) Systemes de lutte nationaux reglementaires National regulatory control systems PM 9/1 (6) Bursaphelenchus xylophilus and its vectors: procedures for official control Specific scope First revision approved in 2009-09. This Standard describes the procedures for official control with the aim of eradicating or containing Bursaphelenchus Second revision approved in 2010-09. xylophilus. Third revision approved in 2011-09. Fourth revision (editorial changes only) approved in 2012-09. Specific approval and amendment Fifth revision approved in 2018-09 First approved in 2002-09. situated in storm- or fire-affected areas, depending on the 1. Introduction Monochamus species involved (Schroder€ et al., 2009). This Standard presents the basis of a national regulatory Transmission of B. xylophilus to live trees during feeding control system for the eradication of Bursaphelenchus by adult beetles can result in the development of wilt dis- xylophilus and associated surveillance to enable early detec- ease in the tree, but only in susceptible species of Pinus tion. It also provides guidance on containment measures to under suitable climatic and growth conditions. prevent further spread, whether from an outbreak during Transmission of B. xylophilus to other tree genera by eradication or from an area of established infestation where maturation feeding may also occur, but does not result in eradication is no longer achievable. the development of wilt. Transmission during oviposition Eradication and containment are defined in ISPM 5 as, can occur on most if not all coniferous species provided the respectively, ‘The application of phytosanitary measures to trees are weakened, dying from any cause or have recently eliminate a pest from an area’ and ‘The application of phy- died, thus making them suitable for Monochamus oviposi- tosanitary measures in and around an infested area to pre- tion. Transmission at oviposition can also occur on timber vent spread of a pest’. Unless it can be achieved quickly, a and cutting residues. Known exceptions are Thuja and strategy of eradication has to be accompanied by imple- Taxus, which are not known to be used for maturation feed- mentation of measures for containment to avoid spread ing and egg-laying of Monochamus species or to be hosts while the outbreak is eliminated. of the nematode. Thus, B. xylophilus can be found in the Bursaphelenchus xylophilus, the pine wood nematode, is wood of trees of any coniferous species (except Thuja and an EPPO A2 pest. Details about its biology, distribution Taxus) that has been weakened enough to allow and economic importance can be found in EPPO/CABI Monochamus species to oviposit and transmit the nematode (1997). Its natural means of transmission from tree to tree and not only in wood of Pinus species expressing wilt dis- is by transfer through activity of the adult stages of wood- ease. The nematode is very easily carried by the movement inhabiting longhorn beetles of the genus Monochamus of infested, untreated wood. There are known to be differ- (Coleoptera: Cerambycidae). During the feeding of the ences in susceptibility between different genera of conifers adult insects (maturation feeding by either sex) the nema- and between species of Pinus (Evans et al., 1996; EFSA, tode can be transmitted to the shoots of living trees, and 2013), but given the associated uncertainties these have not during oviposition by the females it can be transmitted to been considered further in this revision of the Standard. the trunks or larger branches, cutting residues or debris, or This Standard addresses the situation when infestation of weakened trees or trees that have recently died or those host trees with B. xylophilus leads to expression of pine ª 2018 OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 48, 503–515 503 504 National regulatory control systems wilt disease as well as the situation when infestation does 2. Outline of the system not lead to expression of pine wilt disease. Data from North America, Asia and Europe (Gruffudd et al., 2016) indicates A national regulatory control system is recommended to all that tree mortality arising from expression of pine wilt dis- EPPO countries for the early detection, containment and ease is determined largely by whether or not mean summer eradication of B. xylophilus. Elements of this Standard are isotherms are above 20°C. Other factors, including soil also relevant to a long-term containment strategy when moisture, host species, tree condition and the level of the eradication is no longer a feasible objective. The system nematode population within the tree, also have an impact described provides sufficient guarantees to allow export of on symptom expression. The lack of wilt symptoms in host commodities within and out of infested and regulated cooler conditions or during the latent period before symp- areas. tom expression may make it difficult to detect B. xylophilus Annual surveys should be carried out for early detection infestation(s) in time for successful eradication. of new outbreaks and for monitoring spread using appropri- This revision of the Standard takes into account new infor- ate methods depending on whether or not wilt symptoms mation on the flight capacity of the vector, the availability of are likely to be seen. an effective pheromone/kairomone attractant for trapping it, Countries are encouraged to develop and test a contin- the possibility of remote sensing for early detection of symp- gency plan for outbreaks of the pest, drawing on guidance toms and the efficacy of emamectin benzoate as a treatment in this Standard and in EPPO Standards PM 9/10 (1) in certain situations. Some demarcated areas were increased Generic elements for contingency plans (EPPO, 2009b) and on account of evidence presented about the flight potential of PM 9/18 (1) Decision-support scheme for prioritizing the vector. Conversely, the size of the clear-cut area was action during outbreaks (EPPO, 2014a). The contingency reduced on account of evidence presented about the lack of plan should take account of climate, host plant distribution infestation found, in practice, in asymptomatic trees felled in (likelihood of symptoms or of latency), vectors present in clear-cut areas. The overall intention of the revision was to the country and the silvicultural practices and socio-eco- rebalance efforts to increase the intensity of surveillance over nomic structure of the forestry sector. In larger countries, a wider area while reducing resources going into felling of different contingency plans may be needed for different probably uninfested trees. regions and circumstances. Key uncertainties remain: firstly, the probability distribu- Publicity should be prepared and disseminated to explain tion of actual flight distances of the vector under different the risks posed by B. xylophilus to landowners, forestry field and physiological conditions (e.g. whether through operators and members of the public who may be affected continuous or fragmented pine stands and whether or not it by measures taken. In particular operators of transport and is bearing eggs and carrying nematodes) and, secondly, the wood handling facilities near the boundary of infested and significance of asymptomatic presence of the nematode. uninfested areas should be encouraged to take simple Asymptomatic presence can occur where temperatures are hygiene precautions to avoid inadvertently moving vectors, high enough for symptom expression, in more tolerant host as well as complying with any measures in place against species and during early, latent, stages of infestation. There moving the nematode on specified commodities. is some evidence that infested trees can be attractive to For containment and eradication of B. xylophilus, in the vectors even in the absence of symptoms (Futai & Takeu- case of new outbreaks, a minimum regulated area around chi, 2008) The mechanism for this attraction is thought to the infested tree(s) with a radius of at least 20 km should be a change in the volatiles emitted from an asymptomatic be established, and measures should be taken in the tree (Futai & Takeuchi, 2008), However, since these sequence recommended by this Standard. This radius is jus- changes in the spectra of volatiles are not known, early tified by recent data on the flight capacities of Monochamus detection of asymptomatic trees remains a challenge. galloprovincialis (Etxebeste et al., 2016). EPPO Standard PM 8/2 (1) on commodity-specific phy- No findings of B. xylophilus over at least the duration of tosanitary measures for Coniferae (EPPO, 2009a) specifies two vector life cycles, with a minimum of 3 years of requirements for commodities with respect to B. xylophilus. annual monitoring and sampling in the regulated area, can It covers plants for planting, cut branches, isolated bark and be considered as evidence of its successful eradication. various types of wood (such as sawn wood, round wood, wood packaging material, wood chips, hogwood and wood 3. Surveillance residues) of coniferous species. It recognizes that the risk associated with commodities from countries where Early detection of new outbreaks is a very important factor B. xylophilus is widespread is significantly greater than that in determining the likelihood of eradication. from countries where the pest is of limited distribution and Detection surveys should be carried out annually on sus- under official control with the prospect of eradication. Offi- ceptible plants, susceptible wood and bark and on the vec- cial application of this system should enable a country to tor to determine the presence of B. xylophilus. Surveys qualify for less stringent measures required by other coun- should also be partly pathway-based, concentrating on tries to which it exports. potential points of introduction of B. xylophilus. Surveys ª 2018 OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 48, 503–515 PM 9/1 (6) B.