turfgrass weed biology and identification
DESCRIPTION
Turfgrass Weed Biology and Identification. Tim R. Murphy The University of Georgia. Why do we control weeds in turfgrasses?. Weeds. Compete with desirable plants for sunlight, moisture and nutrients Reduce yields or quality of harvested product. Turfgrass Weeds. Reduce quality - PowerPoint PPT PresentationTRANSCRIPT
Turfgrass Weed Biology Turfgrass Weed Biology and Identificationand Identification
Tim R. MurphyTim R. Murphy
The University of GeorgiaThe University of Georgia
Why dowe control
weeds inturfgrasses?
WeedsWeeds
Compete with desirable plants for sunlight, Compete with desirable plants for sunlight, moisture and nutrientsmoisture and nutrients
Reduce yields or quality of harvested productReduce yields or quality of harvested product
Turfgrass WeedsTurfgrass Weeds
Reduce qualityReduce quality
- - leaf width, shape, color differencesleaf width, shape, color differences
Reduce densityReduce density- out-compete turfgrasses, can lead to - out-compete turfgrasses, can lead to
erosionerosion
Decrease aesthetic value or utility of the Decrease aesthetic value or utility of the turfgrass.turfgrass.
- difficult to mow, disrupt uniformity of playing - difficult to mow, disrupt uniformity of playing surfaces, safety considerations, attract insectssurfaces, safety considerations, attract insects
Control Control vs.vs. EradicationEradication
Control
Process of limiting a weed infestation to a level that is beneficial (economics, aesthetics, safety, etc.).
Eradication
Elimination of all plants and plant parts of weed species from an area.
Developing a Weed Management Developing a Weed Management ProgramProgram
Prevent weed introductionPrevent weed introductionProperly maintain turfgrassesProperly maintain turfgrassesIdentify weeds and learn life cycleIdentify weeds and learn life cycleInitiate control practicesInitiate control practices PreventivePreventive CulturalCultural MechanicalMechanical HerbicidesHerbicides
Why are weeds an annual problem?Why are weeds an annual problem?
Seed and vegetative structure dormancySeed and vegetative structure dormancy
Prolific seed producersProlific seed producers
Spread of seed (wind, birds, humans, etc.)Spread of seed (wind, birds, humans, etc.)
Turfgrass culture selects tolerant speciesTurfgrass culture selects tolerant species MonocultureMonoculture MowingMowing
Characteristics of Most WeedsCharacteristics of Most Weeds High reproductive outputHigh reproductive output
Some weeds produce 1000’s of seeds per plantSome weeds produce 1000’s of seeds per plant
Bimodal reproductionBimodal reproduction (more than one way to (more than one way to reproduce)reproduce)Dandelion – seeds and taproot fragmentsDandelion – seeds and taproot fragmentsVirginia buttonweed – seeds, stem fragments, Virginia buttonweed – seeds, stem fragments, rootsroots
Characteristics of Most WeedsCharacteristics of Most Weeds
Discontinuous germination or sproutingDiscontinuous germination or sprouting
Weed seeds can remain dormant in the soil for Weed seeds can remain dormant in the soil for many years and germinate sporadically. many years and germinate sporadically.
Crop and turf species are bred to NOT have Crop and turf species are bred to NOT have dormancy – hence all seeds germinate at the dormancy – hence all seeds germinate at the same time.same time.
Characteristics of Most WeedsCharacteristics of Most Weeds
Highly dispersibleHighly dispersibleWeeds must be able to colonize and invade.Weeds must be able to colonize and invade.
Ability to Withstand Environmental ExtremesAbility to Withstand Environmental Extremes
Ability to survive unexpected events. Ability to survive unexpected events.
Annual bluegrass and smooth crabgrass are Annual bluegrass and smooth crabgrass are found throughout the entire United States. found throughout the entire United States. (tremendous genetic diversity)(tremendous genetic diversity)
Characteristics of Most WeedsCharacteristics of Most Weeds
EarlinessEarliness
Many weeds germinate early and grow faster Many weeds germinate early and grow faster and taller than desired turf. Thus they are and taller than desired turf. Thus they are capturing resources (light, moisture, nutrients) capturing resources (light, moisture, nutrients) also needed by the turf. Various weed species also needed by the turf. Various weed species found at any time of the year.found at any time of the year.
Weed CompetitionWeed CompetitionCompetition will occur if there is one limiting Competition will occur if there is one limiting
resource needed by two or more plants.resource needed by two or more plants.
Weeds compete for the following resources.Weeds compete for the following resources.
LightLight
WaterWater
NutrientsNutrients
SpaceSpace
Weed CompetitionWeed Competition
Weeds efficiently compete because of:Weeds efficiently compete because of:
Early germinationEarly germination
Rapid seedling growthRapid seedling growth
Large leaf areaLarge leaf area
Extensive root systemsExtensive root systems
Tubers
Thickened portions of rhizomes or roots, serving for food storage and also for propagation (yellow nutsedge example)
Rhizomes
Underground stems that can emit roots from the lower side and leafy stems from the upper side (green kyllinga ex.)
Tubers and RhizomesTubers and Rhizomes
Weeds that produce tubers include purple Weeds that produce tubers include purple nutsedge, yellow nutsedge and Florida betony.nutsedge, yellow nutsedge and Florida betony.
Rhizomatous turfgrasses include bahiagrass, Rhizomatous turfgrasses include bahiagrass, bermudagrass, Kentucky bluegrass, tall fescue bermudagrass, Kentucky bluegrass, tall fescue and zoysiagrass.and zoysiagrass.
Rhizomatous weeds include dallisgrass, Rhizomatous weeds include dallisgrass, nimblewill and kyllinga species.nimblewill and kyllinga species.
Bulbs
Short, vertical, underground organs for food storage or reproduction on which specialized leaves prominently develop (wild garlic)
Weed Life CyclesWeed Life CyclesWeeds are classified as…Weeds are classified as…
Annuals (summer and winter)Annuals (summer and winter)
BiennialsBiennials
Perennials (warm-season and cool-Perennials (warm-season and cool-season)season)
Summer AnnualsSummer Annuals
Germinate in spring or early summerGerminate in spring or early summer Produce seed in the summerProduce seed in the summer Die with cold weather or frostDie with cold weather or frost
Live for only ONE growing season!Live for only ONE growing season!
Summer AnnualsSummer Annuals
GrassGrass BroadleafBroadleaf
Crabgrass speciesCrabgrass species Spotted spurgeSpotted spurge
Foxtail speciesFoxtail species Common lespedezaCommon lespedeza
GoosegrassGoosegrass Prostrate knotweedProstrate knotweed
SandburSandbur
Sedges:Sedges: annual sedge annual sedge
Southern crabgrass
Smooth crabgrass
GoosegrassGoosegrass
Common lespedeza
Prostrate knotweed
Prostrate spurge Milky sap
Chamberbitter, cannonball weed, gripeweed
Winter Annuals Winter Annuals
Germinate in fall or early winterGerminate in fall or early winter Over-winter (very slow growth) during coldest Over-winter (very slow growth) during coldest
monthsmonths Actively grow and produce seed in the springActively grow and produce seed in the spring Die in summer as temperatures riseDie in summer as temperatures rise
Live for only ONE growing season!Live for only ONE growing season!
Winter AnnualsWinter AnnualsGrassGrass BroadleafBroadleaf
Annual bluegrassAnnual bluegrass Chickweed speciesChickweed species
HenbitHenbit
Lawn burweedLawn burweed
Speedwell speciesSpeedwell species
KnawelKnawel
Hop cloverHop clover
Annual bluegrass Annual bluegrass Poa annua Poa annua L.L.
Boat shaped leaf tip
Common chickweed
Lawn burweed (spurweed)
henbithenbit
Henbit
Hairy bittercress
BiennialsBiennials
Germinate in fall or spring when conditions are Germinate in fall or spring when conditions are favorablefavorable
Usually found in rosette stage in 1st YrUsually found in rosette stage in 1st Yr
Produce seed and die in the 2nd growing seasonProduce seed and die in the 2nd growing season
Shiny cudweed
Purple cudweed
Warm-Season PerennialsWarm-Season Perennials
Germinate in spring or summerGerminate in spring or summer Can produce seed in the first summerCan produce seed in the first summer Can produce seed or reproduce by vegetative Can produce seed or reproduce by vegetative
means indefinitely (survive for many years due means indefinitely (survive for many years due to underground structures such as taproots, to underground structures such as taproots, rhizomes, tubers, bulbs and aboveground rhizomes, tubers, bulbs and aboveground structures such as stolons)structures such as stolons)
Warm-Season PerennialsWarm-Season Perennials
GrassGrass BroadleafBroadleaf
DallisgrassDallisgrass Virginia Virginia buttonweedbuttonweed
BahiagrassBahiagrass
SmutgrassSmutgrass
Sedge / kyllinga species:Sedge / kyllinga species: green and false-green green and false-green kyllinga, purple and yellow nutsedgekyllinga, purple and yellow nutsedge
DallisgrassDallisgrass
KyllingaSedge spp.
Virginia buttonweed
Purple Nutsedge – Purple Nutsedge – Cyperus rotundusCyperus rotundus
Introduced, native to Introduced, native to EurasiaEurasiaS. East U.S., CA and AZS. East U.S., CA and AZRanked world’s worst weedRanked world’s worst weedForms chains of Forms chains of interconnected tubersinterconnected tubersPrefers medium to fine-Prefers medium to fine-textured soilstextured soilsHighly adapted to Highly adapted to compacted soilscompacted soils
Yellow Nutsedge – Yellow Nutsedge – Cyperus esculentusCyperus esculentus
Native to North Native to North AmericaAmericaFound in all of U.S.Found in all of U.S.Ranked 16Ranked 16thth worst weed worst weed in worldin worldForms tubersForms tubersCommonly found in Commonly found in sandy soilssandy soilsThrives in non-Thrives in non-compacted soilscompacted soils
Cool-Season PerennialsCool-Season Perennials
Germinate in fall or winterGerminate in fall or winter Can produce seed in the first springCan produce seed in the first spring Can produce seed or reproduce by vegetative Can produce seed or reproduce by vegetative
means indefinitely (survive for many years due means indefinitely (survive for many years due to underground structures such as taproots, to underground structures such as taproots, rhizomes, tubers, bulbs and aboveground rhizomes, tubers, bulbs and aboveground structures such as stolons)structures such as stolons)
Cool-Season PerennialsCool-Season PerennialsGrassGrass BroadleafBroadleaf
Perennial ryegrassPerennial ryegrass Ground ivyGround ivy
Tall fescueTall fescue In. mock strawberryIn. mock strawberry
DandelionDandelion
Wild violetWild violet
Yellow woodsorrelYellow woodsorrel
White cloverWhite clover
Grass-Like:Grass-Like: Wild garlic Wild garlic
Perennial ryegrass clumps
Wild garlic
Wild garlicbulbs and bulblets
DandelionDandelion
Dandelion
Wild violet
Ground ivy
Identify the Weed ProblemIdentify the Weed ProblemREAD textbooks and periodicalsREAD textbooks and periodicals
Keep a diagnostic tool kit - hand lens, etc.Keep a diagnostic tool kit - hand lens, etc.
Know the life cycle of the pest (What temp. does a Know the life cycle of the pest (What temp. does a specific weed seed germinate?) specific weed seed germinate?)
Is the weed the cause or effect of the problem?Is the weed the cause or effect of the problem?
Confirm your diagnosisConfirm your diagnosis
ACES - ANR-616 UGA-CES
$14.00
www.amazon.com
* 214 weed species*575 color photos*Control info for each weed
$88.00
Turfgrass Web PagesTurfgrass Web Pages
www.georgiaturf.comwww.georgiaturf.com or .org or .org
437 photographs of 193 weeds437 photographs of 193 weeds
Control recommendationsControl recommendations
Popular articlesPopular articles
Links to turfgrass organizations, GA Links to turfgrass organizations, GA automated weather networkautomated weather network