Number2‐May4,2015
NoxiousWeeds
TheStateofIllinoishastwo“legal”lists
ofproblematicplantsthatrequireatten‐
tion–NoxiousWeedsandExoticPlants.
TheIllinoisNoxiousWeedLaw,setinto
IllinoisAdministrativeCode,lists10
weedsthatmustbecontrolledonprop‐
ertyownedormanaged.Theseweeds
havedetrimentaleffectsonpublichealth,
agriculturalcropproduction,oranimal
production.Thislawisunderthedirec‐
tionoftheDirectoroftheILDepartment
ofAgriculture.MostcountiesinIllinois
haveadesignatedWeedCommissioner
forlocalcontrolauthority.
WeedsonthislistincludeCommon
Ragweed(Ambrosiaartemisiifolia),Gi‐
antRagweed(Ambrosiatrifida),Mariju‐
ana(Cannabissativa),MuskThistle
(Carduusnutans),CanadaThistle
(Cirsiumarvense),Kudzu(Puerariamon‐
tana,P.lobata),PerennialSowthistle
(Sonchusarvensis),andvarioussor‐
ghumsincludingJohnsongrass(Sorghum
halepense)andColumbusgrass(Sor‐
ghumalmum).
Thetworagweedsneedonlytobecon‐
trolledwithinthecorporatelimitsofcit‐
ies,townsandmunicipalities.Allother
weedsonthelistmustbecontrolledan‐
ywhereinIllinois.
Noxiousweedsmustbecontrolledso
theydon’tproduceseedsoranyother
meansforpropagating,ortotallyeradi‐
catedusinglegalmeans.
Itshouldbenotedtheseareoutdoor‐
grownweeds.That’simportantnow
withoneoftheweeds.
MoreinformationontheILNoxious
WeedLawcanbefoundat:
http://www.agr.state.il.us/Laws/Regs/
8iac220.pdf(DavidRobson)
ExoticWeedAct
TheIllinoisExoticWeedAct,alsosetin‐
toIllinoisAdministrativeCode,isman‐
agedbytheILDepartmentofNatural
Resources.Thesenon‐nativeplants,
whenplanted,willspreadbyseedsor
vegetativepropagules(rhizomes,bulbs,
tubers,corms,etc.)andnaturalize,de‐
gradingnaturalcommunities,reducing
thevalueoffishorwildlifehabitat,and
threateningIllinoisendangeredor
threatenedspecies.
Formostoftheseplants,it’stheseeds
thathavecausedtheseplantstospread,
particularlyinforestedandwooded
areas.
Thislawdoesn’trequiretheowneror
managerofpropertytoremovethese
plantsliketheILNoxiousWeedLaw.
However,doeverythingtopreventthem
fromspreading,includingremoving
flowersbeforetheysetseed.TheAct
doesstateyoucannotsellorplantthese
withoutpermissionfromIDNR.
Thefollowingspeciesareonthelist.
Additionally,andthisiscrucial,ALL
theircultivarsareincluded,nomatter
whoorwhatsaysthecultivarsarester‐
ile.AnycultivaroftheseplantsCAN‐
NOTbelegallysoldorplantedinIllinois
withoutapermitfromIDNR.Thisin‐
cludesalltheso‐calledsterilepurple
loosestrifecultivarsaswellastheFine‐
Line®buckthorns.
IncludedplantsincludeJapanesehoney‐
suckle(Lonicerajaponica),multiflorarose
(Rosamultiflora),purpleloosestrife(Lyth‐
rumsalicaria),commonbuckthorn(Rham‐
nuscathartica),glossybuckthorn(Rhamnus
frangula),saw‐toothedbuckthorn(Rhamnus
arguta),dahurianbuckthorn(Rhamnusda‐
vurica),Japanesebuckthorn(Rhamnusja‐
ponica),Chinesebuckthorn(Rhamnusuti‐
lis),andkudzu(Puerarialobata).Kudzuis
theonlyplantalsoontheNoxiousWeedlist.
Atthemoment,ILSenateBill681seeksto
amendtheExoticWeedact,addingbush
honeysuckles(Loniceramaackii,Lonicera
tatarica,Loniceramorrowii,andLonicera
fragrantissima),exoticolives(Elaeagnus
umbellata,Elaeagnuspungens,Elaeagnus
angustifolia),saltcedar(allmembersof
theTamarixgenus),poisonhemlock(Co‐
niummaculatum),gianthogweed(Hera‐
cleummantegazzianum),Orientalbitter‐
sweet(Celastrusorbiculatus),lesser
celandine(Ficariaverna),teasel(all
membersoftheDipsacusgenus),and
Japanese,giant,andBohemianknotweed
(Fallopiajaponica,syn.Polygonumcuspi‐
datum;Fallopiasachalinensis;andFallo‐
piaxbohemica,resp.)tobedesignatedas
exoticweeds.
Interestingly,someoftheaboveareob‐
viousweeds(poisonhemlock,giant
hogweed,teasels)butaresoldforvari‐
ousunsubstantiatedherbalormedicinal
usesontheInternet.
Itshouldbestressedthattheseplants
areNOTcurrentlyillegaltoplantorsell
inIL.Ultimately,itdependsonwhatthe
ILlegislatureandgovernordoesinthe
nextmonth.
Ontheotherhand,weknowthepro‐
posedplantsareterriblyinvasive;a
wisegardener/landscaperwouldre‐
movetheseplantsfromtheirdesignpal‐
ette,andseriouslyconsiderremoving
theseandthedesignatedexoticsfrom
thelandscape.
Formoreinformation,referto:
http://www.ilga.gov/legislation/ilcs/ilc
s3.asp?ActID=1735&ChapterID=44
(DavidRobson)
What’sThatYellowWeedinBloom?
Noteverythingyouseethat’syellowthis
timeofyearisdandelion,ordaffodilsor
forsythiaforthatmatter.Someother
speciesfeaturingvibrantshadesofyel‐
lowsarecurrentlyorsoonwillbepreva‐
lentinroadsides,fields,andgardens
particularlyinruralsettings.
Butterweed,alsoknownascressleaf
groundsel,isadditionallyknownasSe‐
neciobymany.ThelatinnamewasSene‐
cioglabellusformanyyearsbutwas
changedinthelastfewyearstoPackera
glabella.Othercommonnamesinclude
ragwortandsquawweed.Regardlessof
whatyoumaycallit,thisisaweedwe
havebeenseeingmuchmorefrequently
inrecentyearsalthoughitisnativeto
NorthAmerica.Ittendstoprefercool,
wetconditionsandiscommoninfields
androadsides.Ithasbeenknowntofind
itswayintonearbylandscapebeds.
Butterweedisawinterannualthatgrows
erectonahollow,succulent,smooth
stemfromabasalrosette.Stemsaretypi‐
callygreenbutcanhaveareddishcolor‐
ingaswell,ofteninverticalstripes.
Stemscanreach3ft.inheight.Leaves
alongthestemaredeeplylobed,smooth,
andoftenglossy.Theflowersofthisaster
aresomewhatdistinct.Appearinginclus‐
tersattheendofthestems,theyare
brightyelloworgolden.Unopenedflow‐
ersaresomewhatroundedinshape.
Slightlylightercoloredouterraypetals
number5to15andsurroundtheslightly
darkercoloreddiskflorets.Thenumber
ofpetalsisusefulindifferentiatingbe‐
tweenthisspeciesandotheryellow
weedsinbloomatthistime.Theseed
headsaredandelion‐likepuffballswhich
aredisseminatedbythewind.
Commongroundsel(Seneciovulgaris)is
similarbutmuchsmalleratonly4‐12
inchestall.Thiswinterorsummerannu‐
alweediserectandmuchbranched.The
leavesofcommongroundselaredark
green,lobed,and2to6incheslong.The
flowersmakethisplantfairlyeasyto
identify:theyareyellow,about1/2inch
wide,andareborneincorymbsnearly3
incheswide.Flowerheadsarecomposed
ofseveralyellowdiskflowers.Thisweed
isoftenfoundinfields,nurseries,and
landscapes.Thisspecies,likebutterweed,
isalsoknownasRagwort.
Yellowrocket(Barbareavulgaris)isa
winterannual,biennial,orsometimes
short‐livedperennialmustard,also
knownaswintercress,bittercress,and
rocketcress.Thebasalrosetteleavesare
darkgreen,thick,andglossy.Young
leavesarerounded,sometimeswitha
heart‐shapedbase.Matureleaveshavea
distinctlobepatternwiththeterminal
lobebeingheart‐shaped.Thesecond
year,3to8floweringstemsareproduced
andaremuchlikethatofbroccoli,which
isarelatedspecies.Thestemsarevery
branchedatthetop.Theflowersare
brightyellowwithonlyfourpetals.The
flowersappearonspike‐likeracemes.
Theyformpyramidalclustersattheends
ofbranches.Plantscanreach2‐3ft.in
heightbutcantoleratemowing.There
aremanysimilarweedsinthemustard
familybuttheybloomlaterintheyear.
Theseweedscanbecontrolledbyhand
removalusingadandelionfork.Besure
tobaguppulledweedsfordisposalso
thatflowersdonotcontinuetodevelop,
producingviableseed.Mowingcanbe
properlytimedsuchthatflowerand
seedproductionisprevented.
Postemergentherbicidessuchascarfen‐
trazone,MCPA,MCPP,dicamba,2,4‐D,
canbeapplied.Treatingplantswhen
theyareyoungandactivelygrowing(in
thefall)wouldbebest.
Sources:
WeedsoftheNortheast.(1997).RichardH.
Uva,JosephC.Neal,andJosephM.DiTo‐
maso.Ithaca,NY:CornellUniversityPress.
http://ipm.missouri.edu/IPCM/2010/4
/Weed‐of‐the‐Month‐Cressleaf‐
Groundsel‐or‐Butterweed/
http://www.msuturfweeds.net/details/
_/yellow_rocket_35/
http://www.weedalert.com/details.php
?id=123
http://extension.psu.edu/pests/weeds/
weed‐id/yellow‐rocket
(MichelleWiesbrook)
ModifiedGrowingDegreeDays(Base
50°F,March1throughApril29)
plants.Formoreinformationseethe
attachedannouncement.Theeventis
freeandopentothepublic,butregistra‐
Station
Actual
HistoricalAvg.
One‐Week
Two‐Week
tionisrequired(seebelowfordetails).
Location
Total
(11year)
Projection
Projection
Freeport
189
151
248
316
Pleaseforwardtothisanyonethatmight
St.Charles
179
148
234
298
DeKalb
178
170
241
314
beinterested.
Monmouth
240
203
307
388
Peoria
255
227
327
412
Champaign
252
227
327
412
Springfield
329
258
399
495
ISAMIllinoisInvasiveSpecies
Brownstown
303
301
387
487
Belleville
367
321
453
556
Symposium
RendLake
403
352
496
607
May28,2015
Carbondale
390
339
477
579
Dixon
410
373
503
611
UniversityofIllinoisExtensionOffice
Springs
801NCountryFairDrive
Insectdevelopmentistemperaturede‐
Champaign,IL61821(ChampaignCounty)
pendent.Wecanusedegreedaystohelp predictinsectemergenceandactivity.
TheIllinoisInvasiveSpeciesSymposium
Home,Yard,andGardenreaderscanuse isaone‐day,all‐taxasymposiumthat
thelinksbelowwiththedegreedayac‐
featurestalksoncurrentandemerging
cumulationsabovetodeterminewhat
issuessurroundinginvasiveplants,dis‐
insectpestscouldbeactiveintheirarea. eases,insects,andanimalsinIllinois.
Featuredastheculminationofthe2015
GDDofLandscapePests
IllinoisInvasiveSpeciesAwareness
GDDofConiferPests
Month,theeventalsoincludesthecer‐
emonyforthisyear’sInvasiveSpecies
Degreedayaccumulationscalculated
AwarenessMonthAwards.
usingtheIllinoisIPMDegree‐DayCalcu‐
lator(aprojectbytheDepartmentof
Registration:
CropSciencesattheUniversityofIlli‐
Thiseventisfreetothepublic,butspace
noisandtheIllinoisWaterSurvey).
islimited.Registrationispreferred.Save
(KellyEstes) yourseatat:
http://web.extension.illinois.edu/units/
event.cfm?UnitID=480&EventID=68615
IllinoisInvasiveAwarenessMonth
Symposium
Directions:
Detaileddirectionscanbefoundonthe
JoinusforthesecondannualIllinoisIn‐
UniversityofIllinoisUnit13website:
vasiveSpeciesAwarenessMonth(ISAM) http://web.extension.illinois.edu/cfiv/fi
SymposiumattheUniversityofIllinois
ndus.html
Extensionoffice,inChampaign,ILon
Thursday,May28thfrom9:30amto4
Agenda
pm.Itwillbeagreatopportunityto
(KellyEstes)
learnmoreaboutwhatishappeningon
theinvasivespeciesfrontthroughout
Illinois.Theeventwillfeaturetalks
PhomopsisCankers
aboutinvasivespeciesrangingfrom
snakefungaldiseaseandwhite‐nose
ThereareanumberofspeciesofPho‐
syndromeinbatstoaquaticinvasive
mopsisfungiwhichcausecankersona
widevarietyofhosts.Themostcommon
ornamentalhostsincludejuniper,red
cedar,Russianolive,andholly.Thecan‐
kersusuallybeginassmall,deadareas
onthebranchesandshoots.Asthedis‐
easeprogresses,thecankerscoalesce
untiltheygirdlethebranch.Alltissue
pastthatpointwilldie,leadingtotip
blightanddieback.
Thefungusoverwintersincankerson
infectedplants.Infectionresumesin
springduetothewetenvironmental
conditionswhichfavortheproduction
andspreadofspores.Wounds,including
pruningcuts,areaneffectivepointof
entryforthefungus.Reinfectioncanoc‐
currepeatedlyduringthegrowingsea‐
soniffavorableconditionscontinue.
Phomopsiscankersareoftenassociated
withstressedplantsandarerarelyfatal
ontheirown.However,theydamagethe
aestheticsofthehostandfurtherin‐
creasetheamountofstressonthehost.
Stressedplantsaremoresusceptibleto
pathogensandpests,andlessableto
repairdamagecausedbybioticandabi‐
oticfactors.
AlreadythisyearthePlantClinichasre‐
ceivedsamplesofjuniper,holly,and
kerriaplantswithPhomopsiscankers.
Onherbaceousstemsthecankersoften
appearasroundoroblongdarkbrown
toblacklesions.Thecenterofthele‐
sionsmaybealightercolor,darkening
asthesurroundingplanttissuedies.
Onwoodyplants,thecankersmaybe
moredifficulttosee.Lookforsunken
areaswithadarkermargin.Youmaybe
abletofindcankersbylookingatthe
areaofthebranchbetweenthehealthy
andtheaffectedleavesorneedles.The
sapwoodunderthebarkisusuallydark
brownorblack,indicatingtissuedeath.
Onjunipersandredcedars,themost
commonsymptomofPhomopsisistip
dieback.
ManagementforPhomopsiscankersfo‐
cusesonculturaltechniques.Because
thefungusdoesnotoverwinterinthe
soil,pruninganddestroyinginfected
shootsorbranchesisaneffectivewayto
reducetheamountofthefungusinthe
landscape.Wheninstallingplants,space
themappropriatelytoallowforgoodair
movement.Largerplantscanbepruned
toincreaseairmovementandallowfor
morethoroughdryingofplanttissue.
Fungicideswiththeactiveingredient
thiophanate‐methylarerecommended
foruseagainstthisdisease.Ensurethat
anyfungicideyouplantouseislabeled
foruseonthehostplantsyouaretreat‐
ing.(DianePlewa)
InsecticidesinBeddingPlants
Therehavebeenconcernsabouttheuse
ofneonicotinoidinsecticides,particular‐
lyimidacloprid,clothianidin,thiameth‐
oxam,anddinotefuran,inbedding
plantspurchasedatgardencenters,and
theireffectsonhoneybeesandother
pollinatinginsects.Muchofthisinterest
wasgeneratedbyareportbyFriendsof
theEarthofanalysesconductedonbed‐
dingplantsbeingsoldingardencenters
inspring2013andpublishedlaterthat
year.AreviewarticleIwroteisat
http://web.extension.illinois.edu/ipr/i8
739_829.html#124754.Thiswasfol‐
lowedbyamoreextensivestudy,Gar‐
denersBeware2014,Bee‐ToxicPesticides
Foundin“Bee‐Friendly”Plantssoldat
GardenCentersAcrosstheU.S.andCana‐
dathatcanbeaccessedat
http://libcloud.s3.amazonaws.com/93/
3a/3/4738/GardenersBewareReport_2
014.pdf.
Earlierthisyear,Lowe’sannouncedthat
theywillphaseoutsalesofneonico‐
tinoidinsecticidesby2019astheyiden‐
tifyreplacementinsecticides.Manygar‐
dencentersarerequiringthatgrowers
labelbeddingplantsastowhetherneon‐
icotinoidsinsecticideshavebeenused
onthem.
AmericanHort,SocietyofAmerican
Florists,HorticulturalResearchInsti‐
tute,andAmericanFloralEndowment
issuedastatementinresponseto
Lowe'spositiononneonicotinoidin‐
secticidesasfollows:
April9,2015(Washington,D.C.)‐As
professionalhorticulturists,wegrow
trees,plantsandflowers,andhealthy
trees,plantsandflowersarecritically
importanttohealthybeesandhealthy
beehabitats.Pollinatorhealthisahighly
complexissue,andwerecognizethat
theremanyfactorsthatcanaffectbee
health.Althoughtheimproperuseof
pesticidescanharmbees,agrowing
numberofcredibleindependentstudies
indicatethatneonicotinoids,whenused
asdirected,arenotthecauseofwide‐
spreadbeehealthissues.
Consumerswantplantsthatarehealthy,
beautifulandpest‐free,andneonico‐
tinoidshaveproventobeamongthe
mosteffectivepestmanagementtools
available.Neonicotinoidsalsoareamong
thesafestproductswehaveforbothour
employeesandtheenvironment.
Lowe'spositionissurprising,considering
themostrecentandpositivereportson
thestateofhoneybeehealth(NASShon‐
eyreport)andrecentpeerreviewedre‐
search.Thisisanissueforwhichsound
sciencemusttakepriority.Plantgrowers
areexpertsonhowtoproducehealthy
plants.Weembracethechallengeofpro‐
tectingbeeandpollinatorhealthandthe
opportunitytobepartofthesolution.We
willcontinuetofundimportantresearch
onthehealthofbees,andguidehorticul‐
tureonsafeandresponsiblepestman‐
agement.Horticulturewilllooktothe
bestsciencetoguideourefforts.Forad‐
ditionalinformationonwhathorticulture
needstoknowaboutpollinatorhealth,
viewourvideoat
http://bit.ly/ProtectingPollinatorsVideo.
Thefullstatementisat
http://files.ctctcdn.com/cfdf4ef7001/3f
2a086b‐d1bc‐417e‐89c7‐
e6f0d79e4ea3.pdf.
Therearenumerousresearchstudies
thatshowlinksbetweenneonicotinoid
insecticidesandotherpesticideswith
honeybeeandotherpollinatordeclines.
Therearealsonumerousstudiesthat
showlinksofotherfactorswiththese
declines.PerhapsthejointEPAandUSDA
reportonpollinatordeclineissuedin
May2013isthemostcomprehensive.My
reviewarticleofthatreportisat
http://web.extension.illinois.edu/ipr/i8
627_829.html#123485.
Itisnotpossibletoprovethatneonico‐
tinoidinsecticidesinbeddingplantsand
thoseusedonhomegardensandland‐
scapesarenotmajorfactorsinhoney
beeandotherpollinatordeclines.Itis
impossibletoproveanynegative.How‐
ever,variousstudiesandreportsindi‐
catethattheseinsecticidesprobably
playonlyaminorroleinthesedeclines.
Manyexpertsfeelthatbesidesrelatively
lowlevelsofinsecticidesinthepollen
andnectaroftreatedplants,thereisa
dilutioneffectbynon‐treatedplantsthat
arevisitedinthelandscape.Thisistem‐
peredbyrecentresearchshowinga
preferenceinhoneybeesandbumble‐
beestoneonicotinoid‐treatedplants
(http://www.nature.com/nature/journ
al/vaop/ncurrent/full/nature14414.ht
ml#close).Honeybeesandbumblebees
havepreviouslybeenshowntohavea
preferencefornicotine,sothisprefer‐
enceforneonicotinoidsisnotacom‐
pletesurprise.
TheEuropeanCommission’stwo‐year
moratoriumonneonicotinoidinsecti‐
cideuseonfloweringcropsendsatthe
endof2015.Theresultinganalysesand
reportshouldbeusefulinunderstand‐
ingthesituation.Francestoppedtheuse
ofneonicotinoidinsecticidesin1999
andstillhashoneybeecolonycollapse
disorder.Arecentreportstatesthat
Australiadoesnothavecolonycollapse
disorderandusesneonicotinoidinsecti‐
cides,butdoesnothavevarroamite.
Varroamiteisadebilitatingpestofhon‐
eybeesthatalsotransmitsseveralviral
diseasestohoneybees.
UniversityofIllinoisExtensioncontin‐
uestorecommendtheuseofneonico‐
tinoidinsecticidesincontrollinginsect
pests.Wewillcontinuetodosoaslong
astheiruseissupportedbyresearch
showingtheyareeffectiveincontrolling
pestswhilepresentingacceptablerisks
tohumanhealthandtheenvironment,
includingpollinators.TheIllinoisCom‐
mercialLandscapeandTurfgrassPest
ManagementHandbookalsorecom‐
mendsotherinsecticidesforcontrolfor
thosepestswhereneonicotinoidsare
recommendedexceptfortwoinsects.
Wenowalsorecommendtheuseof
emamectinbenzoatetocontrolthose
twopests,bronzebirchborerandflat‐
headedappletreeborer.Werecommend
theapplicationofimidaclopridanddi‐
notefurantocontrolemeraldashborer
afterthree‐quarterleafexpansionto
avoidpotentialashpollencontamina‐
tion.(PhilNixon)
EasternTentCaterpillar
Easterntentcaterpillarhashatched
throughoutIllinois.Theyareparticular‐
lynumerousinsouthernIllinois,partic‐
ularlyalongI‐70.Removalofthetentsat
nightoroncloudydays,ortheapplica‐
tionofaninsecticidesuchasBacillus
thuringiensiskurstaki(Dipel,Thuricide),
isrecommendedatthistimetoprevent
heavydefoliation.
Thelarvaehatchatbudbreakoftheir
hosts,whichareprimarilytreesinthe
rosefamily.Theseincludecrabapple,
wildblackcherry,hawthorn,serviceber‐
ry,mountainash,floweringplum,and
floweringcherry.Fruittrees,including
apple,peach,apricot,pear,andplumare
alsoattacked.Whennewlyhatched,the
larvaeareblackbutdevelopyellowish
whitestripesdowntheirbackwithina
fewdays.Aftersittingontheeggmass
onthetwigforacoupleofdays,thelar‐
vaemigratetoatwigcrotchwherethey
spinawhite,communalsilktent.
Thecaterpillarsleavethesilktentat
varioustimesthroughoutthedaytofeed
ontheleaves.Leavesareeatenfromthe
margininward,sometimesleavingonly
themidvein,whichsoondries,curls,and
fallsoffofthetree.Heavilyinfestedtrees
canbetotallydefoliated.Defoliated
treestypicallysurvivethisfeedingdam‐
ageandreleaflaterinthespringwith
few,ifany,noticeableeffects.
Fullygrownlarvaereachabout2inches
inlengthandareblack,withanobvious
yellowishwhitestripedowntheback.
Closeexaminationrevealsgoldstripes,
bluespots,andothersmallmarkings.As
thecaterpillarsbecomelarger,theyin‐
creasethesizeoftheirtenttoaccom‐
modatethem.
Whenfullygrown,thelarvaeleavethe
treeandmigrateacrossthegrounduntil
theyfindaprotectedareatopupate
withinasilkcocoon.Adultmoths
emergeinabout2weeksandarebrown,
withwhitebandsacrossthewings.They
areabout1inchlongwith1‐1/2‐inch
wingspans.Aftermating,femalemoths
laytheireggsinreddishbrownclusters
thatwraparoundpencil‐size‐diameter
branches.Eacheggmassisabout1/2
inchlongandcontains100to300eggs.
Theseeggsdonothatchuntilthefollow‐
ingspringwhenbudbreakoccurs.
(PhilNixon)