Vol. 51â1997 - NorthEastern Weed Science Society
Vol. 51â1997 - NorthEastern Weed Science Society
Vol. 51â1997 - NorthEastern Weed Science Society
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82<br />
WEED AFFINITY GROUPS AS A TOOL<br />
IN IPM<br />
M.J.Else'<br />
ABSTRACT<br />
weed classificationsystemproposedinthispaperisdesignedto assistgrowersandthose<br />
involvedi IPMdeliveryin movingtoward ecologically-based weed managementstrategies.<br />
Ecologicall-basedstrategiesaredefinedasthosein whichit isrecognizedthatweed speciesdifferin<br />
their impa on cropsandintheir responsesto crop managementpractices.In ecologicalweed<br />
manage nt, growersandcrop advisorsplanfor weed managementover morethanone cropping<br />
season.In addition,growersconsiderweedspeciesandweed seedbanksizewhen planningtillage,<br />
covercro ping,andcrop andherbiciderotations.<br />
em of classifyingweedsintogroupsmaybe usefulin providinga meansof delivering<br />
neededto implementtheseecologically-based strategies.Inthe "affinitygroup"approach,<br />
eedsof Massachusetts vegetableandsmallfruitfarmshavebeenplacedin sixgroups<br />
basedon cological,biological,andmanagementconsiderations. The groupsare:summerannuals,<br />
winter an uals,low-thresholdweeds,simpleperennials,rhizomatousperennials,andhigh-threshold<br />
weeds. mplesof summerannualsarecommonlambsquarters(ChenopodiumalbumL.),redroot<br />
pigweed ranthusretroHexusL.),andyellowfoxtail(SetanaglaucaL.).Winter annualsinclude<br />
common ickweed(Stel/ariamediaL.)andshepherdspurse(Capsellabursa-pastoris(L.)Medic.).<br />
Low-thre holdweedsin Massachusetts includeyellownutsedge(CyperusesculentusL.),hairy<br />
galinsogaGalinsogaCiliata(Raf.)Blake),andvelvetleaf(AbutilontheophrastiMedic.).Examplesof<br />
simplepe nnialsandrhizomatousperennials,respectively,aredandelion(TaraxacumoIfidnaleL.)<br />
andquac s (Elytrigiarepens(L.)Nevski).High-thresholdweedsareshort-lived,low-growing<br />
weeds . simple,shallowroot system suchascommonpurslane(PortulacaoIeraceaL.),<br />
carpetwe d (MollugovertiCillataL.),andcommonchickweed.<strong>Weed</strong>scanbelongto morethanone<br />
group.<br />
ch affinitygroupisassociatedwithspecificmanagementrecommendations.Rotationto<br />
on crops,for example,canbe awayto reducepopulationsof winter annualweedson a<br />
classifyingweedsas"low-threshold"weedscanbe helpfulin alertinggrowersto the need<br />
e or containthesetroublesomeweedsastheyfirstinvadefarms.<br />
T e affinitygroupapproachisintendedto supplementraditionalherbiciderecommendation<br />
approachs usedby Extensionandothercropadvisorswith culturalandecologicalinformation.It is<br />
designed0 be implementablebytrainedscouts.Thissystemmayserveasa vehiclefor<br />
communi ting informationaboutweed ecologyasit relatesto management,aswell asa meansof<br />
providingspecificproductionrecommendations.<br />
I Extensin Educator,<strong>Weed</strong> IPM,Dept.of PlantandSoil<strong>Science</strong>s,Universityof Massachusetts,<br />
Amherst,MA 0 I035