t NC-4502 VMPR Prblem 1 1.712 Onl ine... R sks Extc F'est Pests ard t-er Im _act n --r_de An Internatinal Online Wrkshp t Reduce Mvement f Frest Pests with a Minimal Impact n Trade Iin us fr a glbal wrkshp and nline Sympsium. Links t the discussin sessins and papers will be "live" in April. ' April 16-29,2001 Industry, s(:ience, regulatry, and _.her indinduals cncerned with trade in.- wd and wd prducts are innted t read abut and discuss the risk f extic pests t glbal frest resurces, and their impact n trade. Included are discussins n current This sympsium made financially and prpsed regulatins t reduce pssible by: :r _ pest f safeguards. entry and the implementatin The American SciedadEspanlade Phytpathlgical Fitpatlgia Sciety _! The prduct scpe f the wrkshp SciedadePrtuguesade The SPC-PlantPrtectinService,Suva, Fitpatlgia _ includes slid wd packing material, Fiji Islands lgs, wd chips, unseasned lumber, The USDA Frest Service._ nursery and prpagative material. t Endrsed by:. " ; The AmericanPhytpathlgicalSciety ọg.. '-. The Asian_sdatin f Scietiesfr Plant Pathlgy The CanadianPhytpathlgicalSciety TheChinese Sciety frplant Pathlgy The EntmlgicalScietyf America ""_' i ' _ The Entmlgical Sciety f China. _._. The MyclgicalScietyf America. The Sdety f American Fresters. The Scietyf Nematlgists ' m _., _,,,,,,,,,, Visit --- http://extic pests, apsnet, rg fr a sneak preview and list f presentatins
Risks f Extic Frest Pests and Their Impact n Trade IV. Hazards assciated with pest pathways and ecnmic impacts E. Seeds, prpagative materials and nursery stck. Michael E. Ostry. Mike has been a research plant pathlgist with the USDA Frest ServiCe, Nrth Central Research Statin in St. Paul, MN fr 32 years. (mstry@fs.fed.us) Intrductin. The arrival, establishment, and spread f extic frest pests have had prfund effects n frest ecsystems and cntinue t have significant ecnmic effects lng after their arrival. Nearly 400 extic insect pests had diseases, many riginating n planting stck, are established in Nrth America. A review f several f the damaging pathgens that : entered Nrth America as hitchhikers n plant material reminds us f the serius cnsequences that accidental intrductins f extic rganisms have n the envirnment. Althugh the mst serius intrductins ccurred befre the enactment f quarantines, the dramatic increase in wrld trade has made the likelihd f new invasins even greater than befre. Mvement f infected plant material In Nrth America the majrity f frest tree diseases that have had the largest impacts resulted frm the accidental imprtatin, prpagatin, shipment and planting f infected nursery stck. Pathgens, even well knwn rganisms, are tten difficult t detect in nurseries. Diseased seedlings r ther frms f plant materials are ften asymptmatic when they are shipped and planted resulting in the rapid and widespread utbreaks f extic rganisms. In additin, hitchhiking rganisms nt damaging t the plant material that harbr them can be mved int new areas and spread t nearby susceptible hst plants resulting in new pest prblems f unrelated plant species. Frtunately the establishment and spread f damaging extic rganisms are prbably rare events. We have n idea hw many accidental intrductins have ccurred in the past and cntinue t ccur but fr ne reasn r anther d nt becme pest prblems. Hwever, several past intrductins have resulted in impacts f such magnitude they underscre the imprtance f minimizing the likelihd f future accidental arrivals. The fllwing classical examples f the establishment f extic frest tree pathgens illustrate the cnsequences f the accidental mvement f pathgens n prpagative materials. Destructin f the American chestnut N greater eclgical impact in recent histry has resulted frm an intrduced rganism than ccurred with the arrival f Cryphnectria parasitica, the pathgen causing chestnut blight. Since its discvery in New Yrk in 1904 the disease has frever changed the eastern frests, rapidly destrying the eclgically and ecnmically valuable American chestnut (Castanea dentata) resurce... 1.:
, Chestnuts and related species frm many cuntries were being brught int the United States in the frm f nuts, rt cuttings and grafting wd in the late 1800's fr rchard establishment and breeding wrk. After the identity f the fungus causing this disease was discvered it was determined t be the same the fungus fund in China and mst likely was accidentally brught int Nrth America n prpagative material. Intrductin f white pine blister rust White pine blister rust caused by Crnartium ribicla is cnsidered t be the mst damaging disease f eastern white pine (Pinus strbus) western white pine (P. mnticla) and sugar pine (P. lambertiana). The fungus was intrduced first t Eurpe frm Asia an d then frm Eurpe t Nrth America n infected plant material as the result f _ imprtatin f pine seedlings t supprt the early refrestatin activities in Canada and the United States. R C. ribicla prduces five types f spres and requires tw hsts, altemating between the pines and currants r gseberries (Ribes spp.). First discvc_'ed in the early 1900's n Ribes in New Yrk, attempts t cntrl this disease were the mst extensive in time, labr and mney in the histry f frestry in the United States. The pathgen cntinues t spread in western Nrth America pssibly frm a shipment f infected seedlings frm Eurpe t Vancuver, British Clumbia. Develpment f Beech Bark Disease Beech bark disease is a damaging disease f American beech (Fagus grandiflia) caused by a scale insect and Nectria fungi. The beech scale insect (Cryptcccusfagisuga) was accidentally imprted int Nva Sctia n rnamental beech frm Eurpe smetime in the late 1800's. The insect is wingless but is easily disseminated by wind, birds, and ther animals. The feeding wunds made by the scale are entry curts fr the native Nectria galligena resulting in large areas f killed bark tissue and eventually the death f severely diseased "'11_. trees. A secnd species, N. cccmea var.faginata, als native t Eurpe and perhaps a third speciesn, chrleuca are als part f this disease cmplex. This illustrates hw the accidental intrductin f an insect that itself is nt a serius pest can interact with a. native fungus that previusly was nt damaging and result in a new disease with serius eclgical and ecnmical impacts. The disease has recently been fund in Michigan near the nrthwestern limit f the natural range f beech. There are numerus ther examples f extic rganisms that have been mved n nursery stck and als f rganisms that have mved t new lcatins within Nrth America. The rle f infected nursery stck in utbreaks f diseases f red pine (P. resinsa) and jack. pine (P. banksiana) is well established. Diseases such as S lerderris canker caused by Gremeniella abietina and sht blights caused by Sircecus cnigenus and Sphaerpsis " sapinea were directly linked t the mvement f infected seedlings frm nurseries. Mre recently, evidence, strngly indicates that anthracnse f dgwd (Crnusflrida and C. nuttallii) caused by Discula destructive and canker f butternut (Juglans cinerea) caused, 2
.. by Sircccus clavigignenti-juglandaceanlm are diseases that may als have been intrduced int Nrth America n nursery stck, r seed. These examples f inadvertent mvement f damanng frest pests and their cnsequences are ample evidence fr the necessity f increasing ur effrts t minimize future prblems nt nly frm knwn pathgens and insect pests, but mre imprtantly frm unknwn pests r new races f pathgens. The risk f the spread f extic insect pests and pathgens thrughut the wrld is high, especially in light f the increasing internatinal mvement f wdy plant material fr frestry and hrticultural uses. _ References Campbell, F.T..and S.E. Schlarbaum. 1994. Fading Frests Nrth American Trees and the Threat f Extic Pests.. Natural Resurces Defense Cuncil, New Yrk, NY. 47p. Gibbs, J,N. and D. Wainhuse. 1986. Spread f frest pests and pathgens in the nrthern. hemisphere. Frestry 59:141-153. Liebhld, A.M., W.L. MacDnald, D. Bergdahl, and V.C. Mastr. 1995. Invasin by Extic Frest Pests: A Threat t Frest Ecsystems. Frest Science Mngraph 30 Vl. 41, 49p. Figure Captins Fig. 1. Manyinsect pests and pathgens are difficult t detect in nurseries resulting in the accidental shipment f damaging rganisms.. Fig. 2. Chestnut blight has resulted in the death f the nce majestic chestnut, reducing them t multiple-stemmed stump spruts. Fig. 3. White pine blister rust kills trees f all ages and makes restratin f the species difficult in many parts f its ff,hal range, Fig. 4. American beech affected by beech bark disease illustrating the white waxy ' materialsecreted by the scale and the rughened bark f trees severely affected by this insect-fungus cmplex. Fig. 5. Butternut killed by a canker caused by what is believed t be an extic pathgen., 3
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