A Review of Leafy Spurge, Euphorbia esula (Euphorbiaceae), the Most Aggressive Invasive Alien in North America

2011·0.84 MB·

by  Ma Jinshuang

云 南 植 物 研 究 , :
暋2010 Suppl灡桗桏 19~45
ActaBotanicaYunnanica
暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋 暋暋暋暋暋暋
AReviewofLeafySpurge Euphorbiaesula Euphorbiaceae
, ( ),
theMostAggressiveInvasiveAlieninNorthAmerica*
**
MAJin灢Shuang
(ShanghaiChenshanPlantScienceResearchCenter,ChineseAcademyofSciences,Shanghai201602,China)
Abstract
:Leafyspurge(EuphorbiaesulaL.,s.lato.)nativetoEurasiaisoneofthemostnotoriousinvasive
plantinNorthAmerica.Inordertofullyunderstandthecurrentsituationwell,detailsoftaxonomy,biology,
physiology,invasion,damageandloss,aswellasvariouscontrolsofleafyspurgehavebeenreviewedhere,
andconciseprospectsandsummaryarealsodiscussed,withmorethan200referencescitedaswell.
Keywords
:Euphorbiaesula;InvasivePlant;NorthAmerica;Review
CLCnumber DocumentCode ArticleID
:Q948暋暋暋暋 :A暋暋暋 暋暋 :0253灢2700(2010)Suppl灡桗桏灢019灢27
Introduction
glespecies(EuphorbiaesulaL.,sensu.lato.),
Leafyspurge(EuphorbiaesulaL.,s.la灢 oranaggregateoftwoormorespecies,notonly
to.),anativeperennialherbfromEurasia,acci灢 inEurasia (Geltman,1998;Ma,1997;Rad灢
dentintroducednearly180yearsagofromEu灢 cliffe灢Smithand Tudin,1968),butalsoin
rope,hasbecomingaseriousandaggressivein灢 North America (Dunn and Radcliffe灢Smith,
vasivealienintheNorth America,andcosts 1980;BiesboerandKoukkari,1992).
millionsandmillionsofloss,especiallyinthe Croizat(1945)treated“Euphorbiaesula暠
NorthernGreatPlainsofNorthAmerica. inNorthAmericawithfourtofivespecies(such
Inordertofullyunderstandthecurrentsi灢 asE灡virgataandmanyothers).RecentlyGelt灢
tuationin dealing withthis mostaggressive man (1998)discussedthetaxonomy,ecology
plantinNorthAmerica,detailsoftaxonomy, andgeographyofEuphorbiaesulaL.andEu灢
biology,physiology,invasion,damageandloss, phorbiavirgataWaldst.,& Kit.fromEurope,
aswellasvariouscontrolsofleafyspurgehave andadvocatedtoseparatethemasdifferentspe灢
beenreviewedinthispaper,especiallyinthe ciessincethedifferenceofecologicalelements.
pastmorethantwentyyears,andconcisepros灢 暋暋DunnandRadcliffe灢Smith(1980)usedtwenty灢
pectsandsummaryarealsodiscussed,with eightherbariasheetsofleafyspurgefrom12states
morethan200referencescitedaswell. wereexaminedandcomparedwithEuropeanspeci灢
mensmaintainedastheRoyalBotanicalGardens,
Taxonomyandclassification
Kew,England,andtreatedfivemorphologically
Leafyspurge,Euphorbiaesula L.(Eu灢 separabletaxa:E灡esulas.str.,ors.lato(incl.
phorbiaceae),anativeperennialherbtoEura灢 E灡androsaemifoliaWilld.),E灡virgata(withva灢
sia,isveryvariablespeciesinvegetativeandflo灢 rieties:uralensis&orientalis)andE灡xpseudo灢
ralmorphology,andthishascausedsomeprob灢 virgata.Radcliffe灢Smith (1985)madeataxo灢
lemsinthetaxonomicfield.Taxonomistsdisa灢 nomiclistof78taxaunderthebroad ‘leafy
greeastowhetherleafyspurgeshouldbeasin灢 spurge暞inNorthAmerica,withmanyhybrids,
* Foundationitems:TheprojectwaspartlysupportedbythePBIofNSF(2007灢2010,ledbyDr.PaulBerry,ANN)andbyNYMF
(2001灢2009,ledbyBrooklynBotanicGarden,BKL)
** Authorforcorrespondence;E灢mail:jinshuangma@gmail灡com
云 南 植 物 研 究 增刊
2暋0暋暋暋暋暋暋暋暋暋暋暋 暋暋暋暋暋暋暋 暋 暋 暋 暋 暋 暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋 桗桏
especiallyfromeastandcentralEurope.Hiskey them.However,otherplantnamesarestill
waswithonlylengthdifferencebutnothingreality usedtodayinthetaxonomicfieldandinvasive
tobefollowedorusedinpractice,evenhemade works.
fulllistofmostoftheminNorthAmerica.
DistributionandInvasion
暋暋Ebkeand McCarty (1983)collectedlive
rootmaterialofleafyspurges(Euphorbiaspp.) ThenativedistributioninEurasiaisvery
from38locationsacrossnorthernUnitedStates, wideandalsoverycommonforthemostcoun灢
southernCanadaandfromonelocationinAus灢 triesinAsiaandEurope,fromJapantoPortu灢
tria.Thesematerialswereestablishedinanurs灢 gal,fromPakistantoSweden,from Russiato
eryatLincoln,NebraskaalongwithE灡agrarian ArabianPeninsula.However,itisnotaggres灢
andE灡cyparissias.Compared with A.Rad灢 siveintheirhomelandsincevariousnaturalene灢
cliffe灢Smithwork,andgotfivemorphologically miesandbalancedecosysteminthenature.It
separabletaxa:E灡xpseudovirgata,E灡esula, couldgrowinmostofconditionbothfromnative
E灡uralensis,E灡agrarianandE灡cyparissias. andinvasiveareasinAsia,EuropeandNorthA灢
Morphometrictechniqueswereusedtoana灢 merica,especiallyin mixedprairie,cropland,
lyzerelationshipsinleafyspurgeanditsallies rangeland,pastures,wildland,open woods,
(Cromptonetal灡,1990).Onthebasisofstud灢 marginofforests,roadside,evenun灢grazednat灢
ying26morphologicalcharactersfoundin200 uralareas,fromelevationfromsealevelto2500
collectionsrepresenting32putativetaxa,theau灢 to3000m.
thorsconcludedthatinNorthAmericaonlyfour InNorthAmerica,thefirstspecimencol灢
speciesshouldberecognized,namely,E灡agrar灢 lectedfromNewbury,Massachusetts,USA,in
ianBied.,E灡cyparissiasL.,E灡esulaL.,and 1827,anditwasfoundfrom New Yorkasa
E灡pseudoesulaSchur. “rareplant暠in1876,from Michiganin1881,
Inordertosolvethedifficultintaxonomic from Huron County,Ontarioin1889,from
problem (Harveyetal灡,1988),thewithin灢 Minnesotain1890,fromIowain1899,from
plant,within灢clone,among灢clone,andamong灢 NorthDakotain1909,from Manitobain1911,
sitevariationinleafymorphologyandtriterpe灢 fromCaliforniain1916,Saskatchewanin1928,
noidcontentofthelatexofleafyspurgewere Albertain1933,andBritishColumbiain1939
demonstratedqualitativelyand quantitatively, (Bestetal灡,1980).Leafyspurgerecognizedin
andtheresultshowsthatlatextriterpenoidpro灢 atleastfourstatesandCanadianprovincesin
fileswereusefulindistinguishingE灡lucidax 1913.However,itfirstlabeledasa“weed暠ina
salicifoliaandE灡salicifoliafromEuropeanE灡es灢 NewYorkHeraldEditorialin1921,andithas
ula,E灡waldsteinii,and E灡sequieriana spp灡 occupied19statesandseveralCanadianprov灢
seguieriana,andallMontanaaccessionsprevi灢 incesin North Americaaround1933.During
ouslydescribedfrommorphologicalstudies,and 1949-1950,ithasoccurredinallofsouthprov灢
concludesthatMontanaleafyspurgeandtheEu灢 incesinCanadaexceptNewfoundland.In1970,
ropeanE灡esula,E灡waldsteinii,andE灡sequier灢 itoccupies26statesinUSA;in1979,itoccu灢
ianabelongtoasingletaxon:E灡esula. pies30states;in1997,itoccupies35statesand
Inshort,mostscientistsfrominvasivebiol灢 southCanadianprovinces.
ogyfieldtreatedandusedleafyspurgeinNorth Severalfurthersurveyshavebeenmadefor
AmericaasEuphorbiaesula(sensu.lato.),i. leafyspurgeinNorthAmericatodeterminethe
e.broadsense,notonlyfromtheorybutalso extentoftheinfestations,suchas1930s(Han灢
frompracticesinceitisveryhardtoseparate sonandRudd,1933).In1970s,itisfoundin
增刊
桗桏暋 暋MAJin灢Shuang:AReviewofLeafySpurge,Euphorbiaesula(Euphorbiaceae),theMost...暋 暋21
458countiesin26statesfromcoasttocoast Groton,NY,i.e.CayugaFlora.(Source:In灢
(Reed,1970;Dunn,1979),especiallyitdis灢 vasiveExoticPlantsofCanadaFactSheetNo.
ruptsnaturalandagroecosystemsacrossmuchof 9,June28,2007)
theNorthern GreatPlains (Barkoskyetal灡, Bysearchedtheliteratures,andthroughthe
2000).In1992and1993,thesurveyshowsthat correspondence,Dunn (1985)concludedthe
theleafyspurgehasbeenexpandedintoIowa曚s fourmostprobablewaysleafyspurgewasintro灢
26of99counties,andthepopulationsarerapidly ducedintoNorthAmerica:1)asseedspresent
expandingespeciallyintheLoessHillsandinthe inthesoiloftheballastofcargoshipsfromEu灢
northeasternIowa(HuerdandTaylor,1998). ropeinthe1700sand1800s;2)intheseed
Sofar,thisinvasivealienhasbeenreported stocksofMennoniteimmigrantstotheprairie
from643countiesin35StatesinUSA (except statesfrom Russiainthedecadeof1870to
southeastUSA,northfromOklahomaandTex灢 1880;3)insmoothbromegrassseed (Bromis
astoNorthCarolina,southtoFlorida,accord灢 inermisL.)thatseedsmenintroducedtoCanada
ingtotheUSDAPlantDatabase,searchedat andthenorthernUnitedStatesfromRussianand
July102007),morethan192countiesand10 Hungaryforagecrops;and4)probablybyMen灢
stateshavebeenaddedsincethelastsurveyin nonitessettlinginMinnesotatoimportedmany
1979.InCanada,itisoneoftennationalprinci灢 bushelsofoatsfromRussiathatwereprobably
palinvasivealiens(Whiteetal灡,1993),and contaminatedwithleafyspurgeseeds(Biesboer
widelyspreadinBritishColombia(ntoQuesnel,c. &Koukkari,1992).Andtwomostprobablear灢
53N),Alberta(ntoFortSaskatchewan,nesub灢 easofitsorigin (theUkraineandthePenza
urbofEdmonton;Moss,1974),Saskatchewan ProvinceintheVolgaValleyofRussia)andthe
(nto Maidstone,53灡06N),Manitoba (nto twogeneralareasoforigin(RussiaandEurope)
Gimli,about45minofWinnipeg),Ontario(n havebeendetermined.
tonearThunderBay),Quebec(ntoSt.Nicho灢 Leafyspurge曚sspreadanddispersalwere
las,Levis Co.),New Brunswick (St.An灢 mainlycausedbyhumanactivities (including
drews,CharlotteCo.,NBM;Hinds,1986), farming,logging,husbandry,livestock,travel,
PrinceEdwardIsland (York,York Co;Er灢 lodging,eventrade,import,seedexchange,as
skine,1960),andNovaScotia(NorthSydney, wellasimmigration),sincetheseedofleafy
CapeBretonCo.;Scoggan,1978).Therecord spurgecan曚tbecarriedbywind,anditalsovery
in Henderson Corner,Dawson,from Yukon hardforanimalstobringawayfrom parent
TerritoryofCanada,isalsoreportedrecently plantstoafardistance,andtheycouldbeonly
(Cody,1996). reachedverylimitedareaafterdehiscencefrom
However,no definitetimeoftheleafy capsuleatautumn.Thepotentialcarrier,such
spurgewasintroducedintoNorthAmericainthe as mourning doves (Zenaida macroura L.;
history.Britton (1921)statedthataboutone Bakke,1936),andotheranimalsareverylimi灢
hundredyearsago,possiblyevenearlier,the ted(Blocksteinetal灡,1987;Waldetal灡,2005),
leafyspurge,nativeofEurope,obtainedafoot灢 evensomereportedthatbirds,animalsandeven
holdinEssexCounty,MA;theactualdateof watercouldspreadtheseeds(Messersmithet
itsintroductionisnotdefinitelyknown,buta al灡,1985).
specimenpreservedintheTorreyHerbariumof
InfectionandDamage
ColumbiaUniversity,depositedatNYBG,was
collectedatNewbury,MA,byWilliamOakesin Leafyspurgebecomesaseriouseconomic
1827.Andin1875,itwasantherrecordfrom andecologicaltreattotheproductivityofagri灢
云 南 植 物 研 究 增刊
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culturalandnaturalareas,especiallythecattle, timatetheeconomicimpactsofleafyspurgeon
thepredominantlivestockspeciesontheGreat grazinglandandwildlandinafourstatesregions
Plainof North America (Halaweishetal灡, (Montana,NorthDakota,SouthDakota,and
2002,2003),andreducesrangelandcarryingca灢 Wyoming;Leistritzetal灡,2005).Leafyspurge
pacitybycompetingwithdesirableforagesand infestationongrazinglandwasestimatedtore灢
causinginfestedareastobeundesirabletocattle sultinalossinregionalgrazingcapacitysuffi灢
andwildlife(MasterandNissen,1998).Itises灢 cienttosupportaherdof90000cows.Directe灢
timatedtheleafyspurgehasinfestedabout1606 conomicimpactsonstockgrowers,landowners,
2
185acres(650000hm )inNorthandSouthDa灢 andagribusinessfirmswereestimatedtoexceed
kota,Montana,and Wyoming,andestimated $37millionsannually,whereassecondaryim灢
annualeconomiceffectofinfestationsinthe pactsthroughouttheregionaleconomytotaled
four灢stateareaisabout$130million (Sellet almost$83millions.Impactsonwildlandwere
al灡,1999). smallerbutstillsubstantial.Studyresultsindi灢
Potentialeconomicbenefits (i.e.gross catedtheseriousnatureoftheleafyspurgeprob灢
benefits,notincludingthecostofbiologicalcon灢 leminthenorthern GreatPlainsregionand
trol)frombiologicalcontrolofleafyspurgein helpedtojustifyenhancedcontrolefforts.
thefourstatesregionofMontana,NorthDako灢 Forageproductionanddisappearancewere
ta,SouthDakotaand Wyomingareestimated estimatedinfourdensityclassesofleafyspurge
(Bangsundetal灡,1999).Biologicalagentswere early(LymandKirby,1987).Useofcool灢and
predictedtocontrolabout65% oftheregion曚s warm灢season graminoids,forbs, and leafy
leafyspurgeinfestations,about1灡2millionsa灢 spurgewasestimatedduringthemiddleandthe
2
cres(497000hm )bytheyear2025.Directe灢 endofeachgrazingseason.Cattleuse20%and
conomicimpactsfromcontrolwereestimatedto 2%oftheherbageinthezeroandlowdensity
totalabout$19灡1millionannually,andsecond灢 infestations,respectively,bymid灢season.Mo灢
aryimpactswereestimatedat$39灡3millions, derateandhighdensityinfestationwereavoided
foratotalannualeconomicimpactof $58灡4 untilthemilkylatexinleafyspurgedisappeared
millions. inearlyfall,andherbageavailabilityinzeroand
Arangelandeconomics modelwasdevel灢 lowdensityinfestationdeclined.Herbageusein
opedtoestimatetheeconomicimpactsofleafy moderateandhighdensityinfestationsincreased
spurgeinfestationonbothranchersandregional toanaverageof46%bytheendofthegrazing
economicsin North Dakota (Leistritzetal灡, seasoncomparedto61%inzeroandlowdensity
1992).Leafyspurgeinducedcarryingcapacity infestations.Anannualherbagelossofatleast
reductionofabout580000animalunitmonths, 35%occurredinpastureinfestedwith50%den灢
orenoughfor77000cows,reducedranchers暞 sityormoreofleafyspurge.
annualnetincomenearly$9million.Ranchers Thetestshows (Kronbergand Walker,
didnotspendanother $14 millionininput 1993;Kronbergetal灡,2006)thatsinceleafy
costs,whichreducedregionalbusinessactivity. spurgeisnotgenerallytoxictotheruminalbac灢
Theregionalimpactsareabout$75millionin teria,butthatmicrobialactivityintherumen
reducedbusinessactivityforallsectors.These mayberesponsibleforenhancingleafyspurge
impactsonrancherincomesandregionaleco灢 toxicitytocattle.Sheepgrazingisanexcellent
nomicssuggestthepotentialeconomicreturnsof methodforcontrollinglargeinfestationsofleafy
leafyspurgecontrolcouldbesubstantial. spurge (Laceyetal灡,1984).Althoughthe
Abio灢economicmodelwasdevelopedtoes灢 sheepwillnoeradicatetheweed,withagood
增刊
桗桏暋 暋MAJin灢Shuang:AReviewofLeafySpurge,Euphorbiaesula(Euphorbiaceae),theMost...暋 暋23
managementsystem,they willkeepitfrom NorthDakotalegislatureemphasizedleafy
spreading.Sheepgrazingasaspurgecontrol spurgecontrolinthe1981-1983bienniumby
toolalsohasadvantagesoverherbicides:ranch灢 appropriating $500000foracost灢sharepro灢
ersreceiveahighreturnfortheirinvestment; gram.Also,eachcountywasallowedtoincrea灢
environmentalhazardsarereduced;andspurge sestaxesby1milltobeusedexclusivelyfor
canbecontrolledininaccessibleareas. leafyspurgecontrol.Thefunding wasdivided
LeafyspurgewasfirstobservedinNorth 33暶47暶20betweenthestates,countyandland灢
Dakotain1909,andhasspreadrapidlysince.It owner,respectively.The1983and1985legisla灢
isfoundinall53countiesofNorthDakotainthe turesprovidedadditionalbiennialappropriations
mid1980s,andispresentonnearly7percentof of$500000and $600000,respectively,to
theuntilledlandinthestate(LymandMesser灢 continuethecost灢shareprogramthroughthe1986-
smith,1985a).Lossofhayandbeetcattlepro灢 1987fiscalyear(LymandMessersmith,1985a).
ductionisestimatedat$7millionannuallydue InManitoba,leafyspurgeisaninvasiveweed
bothtoreducedforageproductionfromleafy speciesthatthreatensanestimated340000acres
2
spurgescompetitionandtocattleavoidinggraz灢 (137593hm ).Thestudyestimatesthatthenete灢
inginleafyspurgeinfestedarea. conomicimpactsassociatedwiththeleafyspurgein灢
TheinfectionofleafyspurgeinManitobaof festationinManitobamaybeapproaching$20mil灢
2
Canadawasjustabout7413acres(3000hm ) lionperyear(http://www灡brandonu灡ca/rdi/LSSG/
2
in1952,c.113669acres(46000hm )in1982, issues—and—impact灡htm,searchedatJuly13,
2
and133436acres(54000hm )in1995(Har灢 2007).Thetotalannualeconomicimpacton
ris,2005). pasturelandisestimatedat$16million.Anes灢
2
Aplantpestascomplexandtenaciousas timated225000acres(91054hm )ofgrazing
leafyspurge,infestingnearly2灡5millionacres landisinfestedinManitobawithapotentialim灢
2
(1011714hm )inNorthAmerica,withacon灢 pactofareducedherdsizeof16540head.Leafy
servative1978economicimpactintheUSof spurgecostsManitobansmorethan$5millionper
$10灡5million,hasreachedaserious,ifnot yearinreducedproducerincome($1940040
criticallevel(Nobleetal灡,1979).Theproblem peryear)andreducedproductionexpenditures
ismostsevereonrangelands,pastures,tree ($3104044).Potentialsecondaryeconomic
belts,parks,waterwaysandroadsides.Evenon impactsonotherbusinesssectorsareestimated
cultivatedcropland,whereleafyspurgehasbeen at$11millionperyear.Additionally,landval灢
controlled,itcanreducecropyields10% to uesarepotentiallyreducedbyover$30million.
100%.Amongthem,Minnesotahashighestin灢 Thisbringspotentialpropertytaximplications
2
festationat800000acres(c.323748hm )fol灢 forownersofcroplands.Whiletaxesoninfested
lowedbyNorthDakotaandMontanawith600000 acresmayreduce,otherlandswillhavetomake
2
and543000acres(242811&219744hm ),re灢 upthelostrevenue.
spectively.TheCanadianproblemisestimated InBritishColombia,isolatedpocketsoccur
tobecomparableto Nebraska,whereleafy inthe Thompson,Cariboo,Boundary,East
spurgecurrentlyinfectsatleast321000aces Kootenay,Nechako,andNorthOkanaganareas
(129904hm2),76of93counties,thedirect (Powelletal灡,1994).
lossinforagevalueattributedtoleafyspurgehas InSaskatchewan,theleafyspurgeinfectsap灢
2
beenestimatedatmorethan$2millionannual灢 proximately20000acres(c.8094hm )ofpasture
ly,andestimatesofdirectandindirectlossesex灢 andnativeprairieinadiagonalbeltfromNorthBat灢
ceed$16millionperyear(Masters,2003). tlefordtoEstevan (http://www灡agr灡gov灡sk灡ca/
云 南 植 物 研 究 增刊
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docs/environment/Biocon灡asp,BiologicalControlof turbed,such asthe moundsaround badger
LeafySpurge,AgricultureandFood,Saskatche灢 holes.Thisisespeciallytrueofearthmounds
wan,Canada,searchedonJuly13,2007). nearrocksonwhichbirdsmightperch.
Grasslandbirdpopulationsaredeclining,
Biology
andinvasiveplantspecies,suchasleafyspurge,
maybecontributingtothesedeclinesbyalter Leafyspurge,aperennialherb,oneofthe
habitatquality(Scheimanetal灡,2003). firstplantsemergesintheearlyspring,asearly
Preventionisbestcontrol,especiallyfor asMarchinmostpartsofNorthAmerica.It
leafyspurge!Infestationsofleafyspurgeshould growsallofseasons,fromfloweringtofruiting,
beeradicatedwhentheproblemissmall.Itisa untildeepautumn.Themulti灢branchedinflores灢
mistaketowaituntilthousandsofhectaresare cenceisfromtoppartofthestems,andflowe灢
infestedunderthemisconceptionthattheweed ringfrom MaytoSeptember,andfruitingfrom
canbeeliminatedeconomicallylaterwithherbi灢 JunetolateOctoberorearlyNovember.Polli灢
cides,grazingmanagementorbiologicalcontrol nationis mainlybyinsects,suchasbumble
methods.Seedproductionandseedlingsestab灢 bees,honeybeesandants (Fowler,1983).
lishmentcanbepreventedwithavailablecon灢 Eachindividualplantcouldproduce10-50cap灢
trolsatreasonableapplicationratesandex灢 sules,eachwith3seeds,whichwilldehiscence
pense,butcontrol,onceinfested,willrequires aftercapsuleopenedatmature.
repeatedtreatmentsand/oruseofexpensivea灢 Reproductionofleafyspurgeismainlyfrom
gents(AlleyandMessersmith,1985). seedsandrootsystems(Morrow,1979).How灢
Theseedsaredispersedafewfeetbydehis灢 ever,theaggressiveandcolonizingabilityfor
cenceofthecapsuleandforlongerdistancesby themostpartcanbeattributedtothevigorous
birds,butmanisprobablythechiefagentfor andextensivegrowthoflongroots,whichare
seeddispersal.Theseedsalongwiththefollow灢 alsocapableofregeneration(Raju,1985),and
ingissuesshouldbeconsidered:inthecrop containingabundantorganicreserveswhichthe
seeds,inthehaysandotherfeedfedtothelive灢 nitrogenplaysintheover灢winteringstrategyand
stock,withintheculturaltools,machineriesand regenerativecapacity(CyrandBewley,1989).
otherequipments.Oneleafyspurgeinfestation Thedevelopmentofanextensiverootsystem
inSouthDakotastartedatthespotwhereagrain andtheabilityofrootstoproducebudsenable
threshingmachine,obtainedinIndiana,wasun灢 leafyspurgetoexplorenewhabitatsefficiently
loadedin1918.Thirtyyearslatertheinfesta灢 andtocompletewithotherplants.Asingleleafy
2
tion,coveredover600acres(c.243hm ).Suc灢 spurgeplant,onceestablished,willinhabitan
cessfulestablishmentoflargenumbersofleafy acreinapproximately65years(Strohetal灡,
spurgeseedlingsinclosedgrasslandsisunlikely; 1990).
butwhenthehabitatisdisturbedoropenedin Cytologicalandcytogeneticstudies were
someway,seedlingsemergeandsurvive.Nu灢 carriedoutonpopulationsofleafyspurgeandits
merousrangelandssitesthathavebeen main灢 alliesprimarilyfrom North Americabutalso
tainedingoodorexcellentconditionhavenot fromEurope (Stahevitchetal灡,1988).The
beeninvadedbyleafyspurge,eventhoughthe chromosomenumbersweredeterminedfor126
weedinfestedadjacentcultivatedlandorgrass灢 samplesofE灡esula,11ofE灡cyparissias,1of
landthatwasabusedbyovergrazing.Frequent灢 thehybrid (E灡xpseudoesulaSchur)between
ly,thefirstareasofnativegrasslandtobeinva灢 thesetwospecies,and1ofE灡agrarianBieb.All
dedbyleafyspurgearethosethathavebeendis灢 plantsofE灡esulawerehexaploid.Ofthetotal,
增刊
桗桏暋 暋MAJin灢Shuang:AReviewofLeafySpurge,Euphorbiaesula(Euphorbiaceae),theMost...暋 暋25
125leafyspurgeaccessionshadachromosomenum灢 Galitz(1994)andMessersmithetal灡(1985).
berofn=30;1ofn=25++.E灡cyparissias
Physiology
wasprimarilytetraploid(2n=20),althoughoc灢
casionaldiploids (n=10)wereencountered. Thephysiologicaltestshowsthattheleafy
Tetraploidswerefertile;diploidsweresterile. spurgedominanceinagrazedplantcommunity
Thehybridbetweentwoforegoingspecieshada bytoleratingherbivoremorethanneighboring
chromosomenumberofn=25,indicatingthat plants,notbyavoidingherbivore (Olsonand
theE灡cyparissiasparentwasatetraploid;meio灢 Wallander,1999).Theroleofmatureleavesof
sisinthehybridwasabnormal.E灡agrariawas leafyspurgeininhibitionofrootbudgrowthis
foundtohaveagameticnumberofn=20, alsoreported(Horvath,1999).Mostlargeher灢
whichisthefirstchromosomenumberdetermi灢 bivoresavoidtheinvasiveweedleafyspurge,
nationforthespecies;meiosiswasnormal.Ar灢 however,ithashighnutritivevaluebasedon
tificialcrossesweremadesuccessfullybetween traditionalmeasuressuchascrudeprotein,fi灢
31accessionsofleafyspurge.Seedgermination ber,anddrymatterdisappearanceandiscon灢
oftheF1progenyslightlyexceededthatrepor灢 sumedbysheepandgoats(RobertsandOlson,
tedfornaturalpopulations,and meiosiswas 1999b)becausethematerialfromun灢defoliated
normal.Pollenstainabilitystudiescarriedouton andpreviouslydefoliatedleafyspurgeshoots,
herbarium material.Stainabilitywas100%for mixedindifferentproportionswithgrasshay,
mostofthesamplesstudied.Extensivepollen adverselyaffectssheeprumenmicrobialactivity
sizepolymorphism wasfound.Itissuggested andmassinvitro.Variousstudieshavebeen
thatthisphenomenonsupportsthehypothesis conductedtodeterminethebehaviorofleafy
thatE灡esulaisofallopolyploidorigin. spurgeinaninvasiveconditioninNorthAmerica
Chromosomenumbervariabilityandchro灢 (Horvath,1998).Toxicityinfoliar灢andsoil灢
mosomemosaicism wererevealedthroughcyto灢 treatedleafyspurgeisalsoreported(Rusnesset
taxonomicstudies(Schultz灢SchaefferandGer灢 al灡,1998).Polyamines,austinsandorganogen灢
hardt,1987,1989).Evidencefromthelitera灢 esisinleafyspurgeisalsoreported (Davis,
ture for introgressive hybridization between 1997).Therelationshipbetweenunderground
E灡esulaandE灡cyparissiasaswellas between adventitiousbudsofleafyspurgeandsugars,
E灡virgataandE灡esulawassubstantiated.Chro灢 hormones,andenvironmentisreported(Chao
mosomenumbersinE灡esulawere2n=48to etal灡,2006).Theseasonexpressionpatterns
60,inE灡xpseudovirgata2n=40to64,andin andcharacterizationofleafyspurgerootstorage
E灡cyparissias2n=36-41.Compositeideograms proteinwasstudiedinordertofindpotentialtar灢
ofE灡cyparissias(2n=4x=40),E灡esula(2n= getsforchemicalorbiologicalweedcontrola灢
6x=60)andE灡xpseudovirgata(2n=6x=60) gents(LusterandFarrell,1996).
seemtoindicatesegmentalallopolyploidyatthe Seasonalvariationinnitrogenstoragere灢
tetraploidand hexaploid chromosomelevels. servesintherootsofleafyspurgeandresponses
Basedontheirusefulnessasgenome marker todecapitationanddefoliation(CyrandBewley,
chromosomestheyindicateacloserelationship 1990).Seasonalfluctuationsofcarbohydrates
betweenE灡esulaandE灡xpseudovirgataaswell andnitrogenouscomponentsintherootsofthe
asapossiblecontributionofE灡cyparissiastothe noxiousperennialleafyspurgearestronglyasso灢
hybridnatureofE灡xpseudovirgata. ciated with over灢wintering strategy. Amino
Detailreviewsaboutthebiologyofleafyspurge acidsanddistinctsolubleproteinsaccumulate
couldbefoundinBakke(1936),Bestetal灡 (1980), during fall and remain at elevated levels
云 南 植 物 研 究 增刊
2暋6暋暋暋暋暋暋暋暋暋暋暋 暋暋暋暋暋暋暋 暋 暋 暋 暋 暋 暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋 桗桏
throughoutwinter.Theformationofcarbohy灢 defoliationtreatmentdidnotreducetotalleafy
dratereservesinrootswasnotsignificantlyaf灢 spurgestem densities.Defoliationtwiceina
fectedbydecapitationofselectivedefoliation; growingseasonfor4consecutiveyearreduced
however,maximumaminoacidandsolublepro灢 totalleafyspurgestemdensitiesby55% over
teincontentsweremarkedlyreduced.Studieson non灢defoliatedcontrols.However,cattleuse
organogenesisofleafyspurgeshowsthatall wouldlikelybelimitedinthesetreatmentsdue
partsofleafyseedlingscanberegeneratedwhen tothehighdensityofleafyspurgestems.
isolated(DavisandOlson,1993).Theseeddor灢 Reduced灢tillagepracticeshaveallowedleafy
mancyisalsoreported(Foley,2004),andthe spurgetofestcropland.Thereductioninleafy
resultsshowthattheseedcoat灢imposedseed spurgeinfestationandwinter灢hardinessbyfall
dormancy.Variousfieldsaboutleafyspurgein tillage,orherbicidetreatment wasevaluated
NorthAmericawerealsotestedandreported (LayandMessersmith,1993).Cultivationre灢
(HoganandManners,1992). ducedtheleafyspurgerootsystemfasterthan
Aknownlathyraneesterandanewjatro灢 herbicidetreatmentespeciallyatthe15灢to30cm
phaneesterhavebeenisolatedfromseedsoftwo depth,andcultivatingleafyspurgetwiceeach
differentstandsofNorthAmericanleafyspurge fallfor3yearsprovidedcompetecontrol.
(OnwukaemeandRowan,1992).New macro灢 Severalgrassesarecompetitivewithleafy
cyclicditerpenoidswasalsoisolated(Liuetal灡, spurgeincluding ‘Rebound暞smooth brome,
2002).Fournewjatrophanediterpenoids,esula灢 ‘Rodan暞westernwheatgrass,‘Pryor暞slender
tinA&B(MannersandWong,1985),DandE wheatgrass,and ‘Manska暞pubescentwheat灢
(Guentheretal灡,1998)havebeenisolatedfrom grass.Cultivatingtwiceeachfallafterharvest
theroots,andthedichloromethaneextractof forthreeyearsincroplandcompletelycontrol
thewhole,undriedplant,respectively.Another leafyspurge.Asuccessfullong灢term manage灢
jatrophanediterpene,esuloneCwasalsoisola灢 mentprogramshouldbedesignedforspeciessit灢
tedandreported(MannersandDavis,1987). uationandshouldincludecombinationsofherbi灢
cides,insects,grazing,and/orseedingcompeti灢
Culturalcontrol
tivespecies(Lym,1998).Anothertestwith
Thestrictestdefinitionoftheterm“cultural twelve grass genotypesfrom North Dakota
control暠includespracticesthatcanbeusedon showsthatthe‘Rebound暞smoothbrome,‘Ro灢
cultivatedland.Thislimitsthecontrolpractices dan暞westernwheatgrass,‘Bozoisky暞Russian
topreventive measures,intensivecultivation, wildrye,and ‘Arthur暞Dahurianwildryewith
competitivecrops,oracombination ofthe betterresults(LymandTober,1998),andthey
three.Abroaddefinitionallowsuseofallnon灢 reducedleafyspurgestemdensityanaverageof
chemicalcontrolpracticesincludinggrazinglive灢 63%after3yearsinasiltyclaysoilatFargo.
stockandmowing.However,themostpractical ‘Reliant暞intermediatewheatgrassreducedleafy
controlmeasuresforuseonlargeinfestationson spurgestemdensityeveryyearfor3years,in灢
cultivatedlandincludecombinationsofcultiva灢 cludingan85%reductionthesecondyearafter
tion,competitivecropsandchemicals(Dersc灢 planting,andconsistentlyproducedhighherb灢
heidetal灡,1985). ageyields.‘Rebound暞and‘Reliant暞intermedi灢
Artificialdefoliationwasconductedonceor atewheatgrassaveraged72%leafyspurgere灢
twiceannuallyatvariousphonologicalgrowth duction3yearsafterseedlinginaloamysand
statesofleafyspurgetosimulategrazingbyher灢 soil at Jamestown. ‘Reliant暞intermediate
dedAngoragoats(Kirbyetal灡,1997).Single wheatgrassand‘Manska暞pubescentwheatgrass
增刊
桗桏暋 暋MAJin灢Shuang:AReviewofLeafySpurge,Euphorbiaesula(Euphorbiaceae),theMost...暋 暋27
Pathogen Fungiandothers
providedthe mostconsistentherbageproduc灢 :
2
tion,whichaveragedabout2000kg/hm annu灢 FungirecordedonEuphorbiaspecieshasa
allyfor3years. lot,butverylittleefforthasbeendirectedto灢
wardtheiruse(Harrisetal灡,1985).Thecom灢
BiologicalControl
parisonofmethodsforselectingfungipathogen灢
Biologicalcontrolofweedsisthedeliberate ictoleafyspurgewasreviewed(Yangetal灡,
useofnaturalenemiestoreducethedensityofa 1991).
targetweedtobelowaneconomicthreshold.In ThehostrangeofMyrotheciumerrucaria
classicalbiologicalcontroloneormoreorgan灢 (Hypocreales:Incertaesedis)isolatedfromleaf灢
isms,usuallyinsectsorpathogens,fromanoth灢 yspurgecollectedfromChina,haspotentialasa
erpartoftheworldareestablishedontheweed mycoherbicide against annual herb (Yang,
(Harrisetal灡,1985).Thetestingrepresentsis 1995).LeafyspurgeinoculatedwithMyrotheci灢
veryexpensive,especiallyintheinitialstage. umverrucariahaddeadtopsorshoots with
However,itcontrasttoothermethodsofweed blackenedstemsandblackened,curled,orwil灢
control,oncetheagentisestablishedanddis灢 tedleaves(YangandJong,1995).Myrotheci灢
tributed,thereislittleornocontinuingcost. umverrucaria did notspreadfrom diseased
Theconflictofinterestshouldbeconsideredand plantstohealthyplants,evenwhenthehealthy
evaluatedfirst,eventested,beforeanybiologi灢 plantstouchedthediseasedplantsinthedew
calagentisclearedandreleased.Sofar,thelist tentfor7days.Fourweekoldoryoungerseed灢
ofnon灢Americaninsectsthatattachleafyspurge lingsofleafyspurgegrownfromseedswerekill灢
includes131specieshavebeencollected,anda灢 edwithoneinoculation,butrepeatedinocula灢
boutthree灢fourthsofthemthatfeedonrestrict灢 tionswererequiredtokillolderplants.Pathoge灢
edtothegenusofleafyspurge,includingAph灢 nicitytestson89collectionsofninespeciesof
thonaspp.(Coleoptera:Chrysomelidae).The Euphorbiaandonreedcanarygrass (Phalaris
prospectsareexcellentthatbiologicalcontrol arundinacea)showedthatthepathogenseverely
canreducetheaggressivenessoftheweedon infectedallcollectionstested.
thesesitesbyestablishingspurgeinsectsand Sixmultinucleateandtwobinucleatestrains
pathogensfromEuropeandAsia. ofRhizoctoniaspp.pathogenictotheweedleafy
Effortstomanageleafyspurgewithbiologi灢 spurgewerecomparedinaggressiveness(Caesar
calcontrolbeginin1960s.Andfirstleafyspurge etal灡,1993;Caeser,1994).Pathogenicitywas
bio灢controlagentin U灡S.(the Hyleshawk testedbyinoculatingstemsofleafyspurgeor
moth)isreleasedin1964.In1978,Entomolo灢 plantingrootsorseedsinsoilinfestedwithRhi灢
gistsinitiateasearchforhost灢specificAphthona zoctoniastrains.Theresultsindicatevariationin
spp.inEurope.Thesearchidentifiesfourflea aggressivenesstoleafyspurgeandinhostrange
beetles:A灡cyparissiae,czwalinae,flavaand amongstrainsofRhizoctoniaspp.from which
nigriscutusforfurtherstudy;allareultimately optimumbio灢controlstrainsmaybeselectedfor
importedandreleased.In1985,firstfleabeetle appropriateuse.R230,anisolateofRhizoctonia
(A灡flava)released.In1988,USDA灢APHIS solanianastomosisgroup5fromleafyspurge,
beginsleafyspurgebiologicalcontrolprogram. causedrootandcrownrotsonleafyspurgewhen
In1989,A灡nigriscutiswasapprovedandre灢 inoculatedviasoilingreenhouseexperiments
leased,andA灡lacertosawasapprovedandre灢 (YuenandMasers,1995).Rhizobacteriahave
leasedin1993. beenshowntobephytotoxictoleafyspurgein
Followingbio灢controlsaredetailedinthisreview: laboratoryassays.ThefieldshowsthatPseud灢
云 南 植 物 研 究 增刊
2暋8暋暋暋暋暋暋暋暋暋暋暋 暋暋暋暋暋暋暋 暋 暋 暋 暋 暋 暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋暋 桗桏
omanasfluorescens,deleteriousrhozobacteria, groupandarefoundinanumberofsiteswhere
couldreducerootweightandrootcarbohydrate thistroublesomeperennialweedoccurs(Caesar,
contentby20% from testin North Dakota 1996).Furtherstudiesonthehostrangewere
(Brinkmanetal灡,1999).Toevaluatethepo灢 conductedingreenhouseusingbothEuropean
tentialofRhizobacteriaasbio灢controlagent,the andUSstrainsofFusariumspp.pathogenicto
cellculturesandcallustissuesofleafyspurge Euphorbiaspp.(Caesaretal灡,1999).
weretested(SouissiandKremer,1994).Arap灢 Previousfieldinvestigationsrevealedpatho灢
idmicroplatecallusbioassayforassessmentof gen灢insectinteractionsontherootsofleafy
rhizobacteriaforbio灢controlofleafyspurgehas spurgeleasingtomortality.Thestudyshows
beenreported(SouissiandKremer,1998).Its thatthe mosteffectiveconditionforinducing
rootcolonizationofseedlingsbyrhizobacteriais diseaseandsubsequentmortalityofleafyspurge
alsoreported(Souissietal灡,1997a).Andinter灢 includesasynergism betweenplant灢associated
actionofrhizobacteriawithleafyspurgecallus microorganismsandroot灢damaginginsects(Kre灢
tissuecellsisalsoreported (Souissietal灡, meretal灡,2006).Furthermore,theresultsare
1997b).Itisconcludedthatcallustissuemay valuableforidentifyingsitesforcollectingsoil灢
provideanexcellentworkingmodeltoinvesti灢 bornemicroorganismsonweedsintheirnative
gatethemodeand/ormechanismofactionofpo灢 rangeforevaluationasbio灢controlagentsintheir
tentialbio灢controlagentsontheirhostplants. invasiverange.
LeafyspurgestandsinthePrairieProvinces
InsectsControl
inCanadaweresurveyedforplantpathogens
duringthegrowingseasonsof1981,1982and GassmannandSchroeder(1995)reviewed
1983 (Mortensen,1984).In mostsitessur灢 thehistoryandlessensfromleafyspurgeandal灢
veyed,leafyspurgewasdisease灢free.Themost liedspeciesinsearchingthebiologicalagentsin
frequentdiseasesobservedwereleafspotandtop Europeinthepast40yearswithsolidcomments
diebackcausedbyAlternariaspp.(Dothideo灢 andresults.Moreinsectspecieswerefoundon
mycetes:Pleosporales),andaleafspotcaused themostcommonandthegeographicallymost
bySeptoriaguepini(Mycosphaerellaceae).A widespreadspurgespeciesandonthoseoccur灢
potentialagent,A灡tenuissima was obtained ringinawiderangeofhabitattypes.Theinsect
fromdiseasedplantoftheleafyspurge(Krupin灢 familiesmostfrequentlyassociatedwithperenni灢
skyandLorenz,1983),andtheexperimentsfor alspurgesinEuropearethechrysomelids,sesi灢
A灡anguistiovoideawerealsomade(Yangetal灡, ids,cecidomyidsandanthomyiids.
1990).SeveralfungiwereisolatedofwhichFu灢 Biology,ecology,andhostspecificityof
sarium spp.(Sordariomycetes:Hypocreales) fiveAphthonaspeciesfrom Europehasbeen
werethemostfrequent.StrainsofFusarium studied,andallofthemareunivoltineandover灢
spp.causingrootdiseaseandcrownrotonleafy winteraslarvae(Gassmannetal灡,1996).The
spurgeinnaturalepidemicsandinassociationwith hostrangeofthesespeciesisrestrictedtospecies
standdeclineswereidentifiedasF灡oxysporum, inthesubgenusEsula.Fewthan19of113Eu灢
F灡solani,and F灡proliferate. These species phorbiaspeciesnativetotheUSappeartobepo灢
predominated amongFusarium spp.isolated tentialhost plansfor A灡flava.Release of
from stunted and diseasedfeederrootsand A灡flavaweremadeinMontana(1985-1987),
crowns.TheresultindicatesthatFusarium NorthDakota(1985)andIdaho (1986).The
spp.capableofcausingdiseaseonleafyspurge potentialhostplantrangeoftheEuropeanflea
varyastospecies,virulence,andcompatibility beetle,A灡flava,acandidatebiologicalcontrol