TURF (3B): TURF PEST IDENTIFICATION
AND BIOLOGY - TEST YOUR
KNOWLEDGE
True6or6False:6Wild6violets6are6a6weed.6-6--
The6right6answers6depends6on6the6situation.6The6usual6definition6of6a6weed6is6a6plant6out
6of6place.6Wild6violets6are6woodland6wildflowers,6and6many6people6enjoy6and6propagate6
them.6However,6they6can6invade6turf6stands.6Many6turf6managers6consider6them6to6be6a6
particularly6troublesome6weed.
List6three6characteristics6of6a6weed.6-6--
Most6of6the6plants6we6consider6weeds6are6very6hardy.6Many6can6tolerate6a6wide6range6o
f6environmental6conditions.6They6are6also6good6competitors.6In6fact,6some6plants,6includi
ng6certain6weeds,6produce6chemicals6that6inhibit6the6growth6of6other6plants.6(This6"chemi
cal6warfare"6is6called6allelopathy.)6Many6weeds6produce6a6large6number6of6seeds.6The6s
eeds6of6a6some6species6may6remain6viable6for6long6periods.6Many6weeds6have6very6effe
ctive6ways6to6spread6their6seeds.6Some6weeds6invade6new6areas6by6vegetative6means.6
For6example,6some6plants6send6out6"runners"6(stolons6or6rhizomes)6above6or6below6grou
nd.6In6addition,6many6turf6weeds6grow6low6and6close6to6the6ground,6so6they6can6tolerate6
mowing.
Why,6in6many6settings,6do6turfgrass6managers6want6-6or6need6-6to6control6weeds?6-6--
They6compete6with6desirable6grasses6for6water,6nutrients,6light,6and6space.6Weeds6in6tur
f6reduce6the6uniformity6of6color6and6texture6in6a6stand.6This,6in6turn,6can6reduce6both6the6
aesthetic6and6the6functional6value6of6the6turf6stand.6In6some6situations,6weeds6detract6fro
m6the6appearance6of6a6landscape.6More6importantly,6a6weed6invasion6in6some6sites6wou
ld6make6them6less6serviceable6(ex.6golf6greens)6or6pose6a6safety6hazard6(ex.6profession
al6sports6turf).6Some6weed6species6harbor6insects6and6diseases6that6can6move6to6and6in
fest6ornamental6turf.6Certain6weeds6can6produce6chemicals6that6people6find6irritating6or6
allergenic.
What6characteristics6separate6broadleaf6plants6(dicots)6from6monocots?6-6--
Broadleaf6plants6have6a6network6of6leaf6veins;6flower6parts6in6twos,6fours,6or6fives;6a6tapr
oot,6and6two6seed6leaves.6Grasses6have6parallel6leaf6veins,6flower6parts6in6threes,6a6fibr
ous6root6system,6and6one6seed6leaf.
What6characteristics6can6be6used6to6separate6grasses6from6sedges?6-6--
Grasses6have6round6or6flattened6stems.6Sedges6generally6have6triangular6stems.6When6
looking6down6a6stem,6grass6leaves6come6off6in6two6directions,6Sedge6leaves6emerge6in6t
hree6directions.
, When6do6summer6annuals6germinate?6When6do6winter6annuals6germinate?6-6--
Summer6annuals6germinate6in6spring6or6summer.6Winter6annuals6germinate6in6late6sum
mer,6fall,6or6winter.
A6biennial6plant6completes6its6life6cycle6in...6-6--26years.
Which6types6of6plant6does6not6die6after6flowering6-
6winter6annual,6summer6annual,6biennial,6or6perennial?6-6--Perennial
To6identify6a6grass6or6a6grassy6weed,6you6should6examine6the6bud,6collar,6and6ligule.6Ex
plain6where6to6look6to6see6these6structures6and6what6to6look6for6when6examining6them.6-
6--Bud6-
6Look6for6a6new6shoot.6Cut6through6the6stem6to6see6if6the6leaf6is6rolled6or6folded6in6the6bu
d.
Collar6-
6The6collar6is6the6area6on6the6outer6side6of6the6leaf6where6the6blade6and6sheath6join.6To6
examine6it,6lay6the6leaf6flat,6underside6up.6Use6a6hand6lens6to6check6the6size,6shape,6and
6top6and6bottom6edges6of6the6collar.
Ligule6-
6The6ligule6is6a6structure6that6clasps6the6stem6at6the6junction6of6the6blade6and6the6sheath
.6Remove6a6leaf6from6its6stem6and6look6at6the6upper6surface6where6the6blade6and6sheath
6join.6If6there6is6a6ligule,6examine6it6with6a6hand6lens6to6see6its6size,6shape,6and6texture.
What6is6an6auricle?
6Why6might6examining6it6be6useful6when6identifying6a6grass6or6grassy6weed?6-6--
Auricles6are6appendages6that6project6from6either6side6of6the6collar.6Some6grasses6have6t
hem6and6others6do6not.6The6presence6or6absence6of6auricles6-
6and6their6shape6if6present6-
6can6help6to6identify6grasses6and6grassy6weeds.6Auricles6may6be6slender6or6clawlike,6lon
g6or6short.
You6notice6a6weed6in6a6shady6area6of6your6lawn.6It6has6small,6shiny,6smooth,6bright6gree
n6leaves6and6star-shaped6white6blossoms.6What6do6you6suspect6it6is?6-6--
Common6chickweed,6Stellaria6media
What6are6some6key6features6you6can6use6to6identify6henbit?6-6--
This6broadleaf6weed6is6in6the6mint6family6and6has6a6square6stem.6Its6sturdy,6smooth6ste
m6is6green6to6purple6in6color.6In6spring,6henbit6produces6small,6trumpet-
shaped,6pink6to6purple6flowers6grouped6in6clusters6of66-
106in6whorls6in6the6axils6of6upper6leaves.
AND BIOLOGY - TEST YOUR
KNOWLEDGE
True6or6False:6Wild6violets6are6a6weed.6-6--
The6right6answers6depends6on6the6situation.6The6usual6definition6of6a6weed6is6a6plant6out
6of6place.6Wild6violets6are6woodland6wildflowers,6and6many6people6enjoy6and6propagate6
them.6However,6they6can6invade6turf6stands.6Many6turf6managers6consider6them6to6be6a6
particularly6troublesome6weed.
List6three6characteristics6of6a6weed.6-6--
Most6of6the6plants6we6consider6weeds6are6very6hardy.6Many6can6tolerate6a6wide6range6o
f6environmental6conditions.6They6are6also6good6competitors.6In6fact,6some6plants,6includi
ng6certain6weeds,6produce6chemicals6that6inhibit6the6growth6of6other6plants.6(This6"chemi
cal6warfare"6is6called6allelopathy.)6Many6weeds6produce6a6large6number6of6seeds.6The6s
eeds6of6a6some6species6may6remain6viable6for6long6periods.6Many6weeds6have6very6effe
ctive6ways6to6spread6their6seeds.6Some6weeds6invade6new6areas6by6vegetative6means.6
For6example,6some6plants6send6out6"runners"6(stolons6or6rhizomes)6above6or6below6grou
nd.6In6addition,6many6turf6weeds6grow6low6and6close6to6the6ground,6so6they6can6tolerate6
mowing.
Why,6in6many6settings,6do6turfgrass6managers6want6-6or6need6-6to6control6weeds?6-6--
They6compete6with6desirable6grasses6for6water,6nutrients,6light,6and6space.6Weeds6in6tur
f6reduce6the6uniformity6of6color6and6texture6in6a6stand.6This,6in6turn,6can6reduce6both6the6
aesthetic6and6the6functional6value6of6the6turf6stand.6In6some6situations,6weeds6detract6fro
m6the6appearance6of6a6landscape.6More6importantly,6a6weed6invasion6in6some6sites6wou
ld6make6them6less6serviceable6(ex.6golf6greens)6or6pose6a6safety6hazard6(ex.6profession
al6sports6turf).6Some6weed6species6harbor6insects6and6diseases6that6can6move6to6and6in
fest6ornamental6turf.6Certain6weeds6can6produce6chemicals6that6people6find6irritating6or6
allergenic.
What6characteristics6separate6broadleaf6plants6(dicots)6from6monocots?6-6--
Broadleaf6plants6have6a6network6of6leaf6veins;6flower6parts6in6twos,6fours,6or6fives;6a6tapr
oot,6and6two6seed6leaves.6Grasses6have6parallel6leaf6veins,6flower6parts6in6threes,6a6fibr
ous6root6system,6and6one6seed6leaf.
What6characteristics6can6be6used6to6separate6grasses6from6sedges?6-6--
Grasses6have6round6or6flattened6stems.6Sedges6generally6have6triangular6stems.6When6
looking6down6a6stem,6grass6leaves6come6off6in6two6directions,6Sedge6leaves6emerge6in6t
hree6directions.
, When6do6summer6annuals6germinate?6When6do6winter6annuals6germinate?6-6--
Summer6annuals6germinate6in6spring6or6summer.6Winter6annuals6germinate6in6late6sum
mer,6fall,6or6winter.
A6biennial6plant6completes6its6life6cycle6in...6-6--26years.
Which6types6of6plant6does6not6die6after6flowering6-
6winter6annual,6summer6annual,6biennial,6or6perennial?6-6--Perennial
To6identify6a6grass6or6a6grassy6weed,6you6should6examine6the6bud,6collar,6and6ligule.6Ex
plain6where6to6look6to6see6these6structures6and6what6to6look6for6when6examining6them.6-
6--Bud6-
6Look6for6a6new6shoot.6Cut6through6the6stem6to6see6if6the6leaf6is6rolled6or6folded6in6the6bu
d.
Collar6-
6The6collar6is6the6area6on6the6outer6side6of6the6leaf6where6the6blade6and6sheath6join.6To6
examine6it,6lay6the6leaf6flat,6underside6up.6Use6a6hand6lens6to6check6the6size,6shape,6and
6top6and6bottom6edges6of6the6collar.
Ligule6-
6The6ligule6is6a6structure6that6clasps6the6stem6at6the6junction6of6the6blade6and6the6sheath
.6Remove6a6leaf6from6its6stem6and6look6at6the6upper6surface6where6the6blade6and6sheath
6join.6If6there6is6a6ligule,6examine6it6with6a6hand6lens6to6see6its6size,6shape,6and6texture.
What6is6an6auricle?
6Why6might6examining6it6be6useful6when6identifying6a6grass6or6grassy6weed?6-6--
Auricles6are6appendages6that6project6from6either6side6of6the6collar.6Some6grasses6have6t
hem6and6others6do6not.6The6presence6or6absence6of6auricles6-
6and6their6shape6if6present6-
6can6help6to6identify6grasses6and6grassy6weeds.6Auricles6may6be6slender6or6clawlike,6lon
g6or6short.
You6notice6a6weed6in6a6shady6area6of6your6lawn.6It6has6small,6shiny,6smooth,6bright6gree
n6leaves6and6star-shaped6white6blossoms.6What6do6you6suspect6it6is?6-6--
Common6chickweed,6Stellaria6media
What6are6some6key6features6you6can6use6to6identify6henbit?6-6--
This6broadleaf6weed6is6in6the6mint6family6and6has6a6square6stem.6Its6sturdy,6smooth6ste
m6is6green6to6purple6in6color.6In6spring,6henbit6produces6small,6trumpet-
shaped,6pink6to6purple6flowers6grouped6in6clusters6of66-
106in6whorls6in6the6axils6of6upper6leaves.
