Turfgrass IPM Workshop
November 11, 2011
Sarah J. Wilhelm
Colorado State University
Fort Collins CO

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Planting poor quality seed or sod
Weak, non-competitive turf
 Improper species or cultivar selection
 Poor management practices
 Damaged by traffic, stress, pests

Poa trivialis
Roughstalk bluegrass
Creeping bentgrass

Underfertilized turf
Adequately fertilized turf

Integrated Weed Management
Program for Turf
 Prevent weed introduction
 Properly maintain turfgrasses
 Identify weeds and learn life cycles
 Utilize and evaluate control practices
 Cultural
 Mechanical
 Biological
 Herbicide Use

Good Cultural Practices

Weeds Associated With Compacted Soils
 Annual bluegrass
 Goosegrass
 Knotweed
 Prostrate Spurge

Weeds Associated With Moist or Poorly
Drained Soils
 Annual bluegrass
 Roughstalk bluegrass
 Barnyardgrass
 Bentgrasses

Weeds Associated With Infertile
(Low Nitrogen) Soils
 Black medic
 Plantain
 White Clover

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Learn life cycle and growth preferences
Best ways to manage with cultural practices
Effective and LEGAL herbicide use

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Most are annuals
Crabgrass, foxtails, goosegrass, sandbur, barnyardgrass
Purslane, spurge, knotweed, puncturevine
Aggressive competitors with cool-season (C-3) grasses during the summer months

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Bluegrasses, ryegrass, fescues, bentgrasses are cool-season turf species
Dandelion, thistle, bindweed are cool-season broadleaf weeds
Quackgrass, bromegrass, annual bluegrass are perennial weedy grasses
Grow best (and are easiest to control) during spring and fall

North Carolina State University http://www.turffiles.ncsu.edu/turfid/
Michigan State University http://www.msuturfweeds.net/

 Color Atlas of Turf Weeds. 2008. John Wiley and sons.
 Weeds of the West. 1991. The University of
Wyoming.
 Identifying Turf and Weedy Grasses of the
Northern United States. http://pubsplus.uiuc.edu/C1393.html

 Annual grassy weeds
 Perennial grassy weeds
 Sedges
 Broadleaf (dicot) weeds

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Infestation often goes unnoticed until it has become a major problem
Selective control can be difficult
 Species often related – sometimes same genus
 Limited chemistry/number of herbicides

Summer Annuals
 crabgrass
 goosegrass
 foxtails
 barnyardgrass
 annual (?) bluegrass
 winter annual bromes

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 benefin (Balan) benefin + trifluralin (Team) bensulide (Betasan) corn gluten meal (Amaizing Lawn, WOW, many others) dithiopyr (Dimension) isoxaben (Gallery) – broadleaf weeds only oxadiazon (Ronstar) pendimethalin (Pre-M, Pendulum, Scotts home products) prodiamine (Barricade) siduron (Tupersan) – for use at time of seeding mesotrione (Tenacity) – both pre- and postemergence for annual grasses

DON’T kill weeds seeds
DON’T sterilize the soil
DON’T control weeds you can already see
(except for dithiopyr/Dimension)
DON’T harm trees and other landscape plants whose roots are growing in the lawn
CAN harm the roots of desirable turf

Herbicide
Benefin (Balan)
Benefin + oryzalin
Benefin + trifluralin (Team)
Bensulide (Betasan)
Dithiopyr (Dimension)
Oryzalin (Surflan)
Oxadiazon (Ronstar)
Pendimethalin (Pendulum)
Prodiamine (Barricade)
Crabgrass
Foxtails
G
G-E
F-G
E
G-E
G-E
G
G-E
G-E
Goosegrass
F
F-G
F
P
F-G
F-G
G-E
F-G
F-G
Annual
Bluegrass
G-E
G-E
G-E
P-F
G-E
G-E
G-E
G-E
G-E

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Preemergence herbicide activity ONLY
Excellent N source (10% N)
Cost is about $1.00/pound
Use rate of 20 pounds/1000 sq. ft. provides 2 lbs.
N/1000
Processed CGM provides moderate control of crabgrass and other annual weeds
Will not provide long-term control of perennial weeds
Raw corn meal is NOT effective
Must use licensed sources of GGM to apply legally!

Causes of Unsatisfactory Preemergence
Herbicide Performance
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Applied after weed emergence
Rate applied was too low
Non-uniform application
Insufficient (at application) rainfall or irrigation
Excessive rain immediately after application
High rainfall year
Poor site drainage
Drought
Excessive/prolonged summer heat
Clippings collected before preemergent incorporated

Preemergent herbicide skip

Preemergence Herbicide Efficacy
 Loss of activity may occur if not watered in within 7 to 10 days.
 Losses from photodecomposition and volatilization can be important, especially with sprayable formulations
 Avoid clipping collection

Split Preemergent Herbicide
Applications
Single application at higher rate
Phytotoxicity level
Effective control level
Herbicide
Concentration
1 st
Application
2 nd
Application
Time

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Tall fescue
Quackgrass
Bromegrass
Bentgrass
Zoysiagrass
Bermudagrass
Poa annua
Poa trivialis

Sources of Perennial Grassy Weeds
 Contaminated seed or sod
 Propagules present in soil at establishment
 Introduced in topsoil, organics, topdressing, nursery materials (tree balls)
 Encroachment from adjacent landscape (neighbor lawns, golf courses, farmland, rangeland)
 Tracking by equipment, people, animals
 Intentionally planted

Zoysiagrass patches in Kentucky bluegrass lawn

Managing Perennial Grassy Weeds
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Glyphosate (Roundup), followed by reseeding or sodding
Learn to tolerate the different grass species
There are new herbicides available for application by lawn care professionals that can be used to SELECTIVELY remove tall fescue, creeping bentgrass, rough bluegrass, quackgrass, windmillgrass, nimblewill and bermudagrass from
Kentucky bluegrass lawns. PROPER IDENTIFICATION IS ESSENTIAL!!!

Rough bluegrass (
)

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Coarse, blue-green leaves
Aggressive rhizome former
Rolled vernation
Early spring green-up
Common ag and ditchbank weed
Can be selectively controlled in bluegrass turf with Certainty herbicide (sulfosulfuron)

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Has a novel mode of action based on a naturally produced compound from the bottlebrush plant ( Callistemon citrinis )
Absorbed by leaves, shoots, and roots and rapidly translocated in the xylem and phloem of susceptible plants
Prevents carotenoid production in leaves, leading to destruction of chlorophyll and cell membranes
Highly active at low use rates as a pre- and post-emergence herbicide
Provides selective broad-spectrum dicot and monocot weed control in a number of turf species
Can use at or prior to seeding of proposed labeled turfgrass species
Low toxicity to wildlife and aquatic organisms and short persistence in the environment

Mesotrione (Tenacity) for Bentgrass Control in
Ryegrass and Kentucky Bluegrass
Syngenta Company
 2 applications 0.25 lb ai/A, at 10-14 interval
 3 applications 0.17 lb ai/A, at 10-14 day interval
 80-90% control at 15 weeks after treatment
 Preemergent and postemergent activity on crabgrass, some broadleaf weeds

Grasses and Sedges Controlled by Tenacity
Barnyardgrass (pre and post)
Creeping bentgrass (post)
Crabgrass species (pre and post)
Foxtail, Yellow (pre and post)
Goosegrass (pre and post)
Nimblewill (post)
Yellow nutsedge (post)
Windmillgrass (post)

 Kentucky bluegrass (including Texas x
KBG hybrids) 0.16-0.25 lb. ai/a
 Perennial ryegrass – 0.16 lb. ai/a
 Tall fescue 0.16-0.25 lb. ai/a
 Fine fescues (red, Chewings, hard)
0.16 lb. ai/a

Perennials
 Dandelion, clover, bindweed, thistle, plantain, violet
Annuals
 Spurge, puncturevine, oxalis, purslane
Prevention
 Proper establishment
 Ongoing maintenance
Herbicides
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Gallery (good), grass preemergents (fair)
Many postemergent options

Dicot Weeds Can Be Difficult to Control
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Control is contingent upon herbicide uptake and translocation
Death of the weed may be slow
Mature weeds may not be controlled completely

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Weeds curl and discolor, but don’t die
Weeds appear to have died, but come back
Reasons...
 Weed species
 Weed age
 Weed health/vigor

Seedlings are easier to control than are mature weeds

Actively growing weeds
 good herbicide uptake
 rapid translocation
 more easily killed
Drought-stressed weeds
 poor herbicide uptake
 poor translocation
 difficult to kill

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2,4-D (many names, often with other herbicides) dicamba (Banvel)
MCPP, mecoprop (many brands)
MCPA (many) dichlorprop triclopyr (Turflon Amine, Turflon Ester) clopyralid + triclopyr (Confront) quinclorac (Drive) clopyralid (Lontrel) chlorsulfuron (Corsair) metsulfuron methyl (Manor) carfentrazone-ethyl (Quicksilver; component of Speed Zone, Power Zone) sulfentrazone (Dismiss) (component of Surge and Q4) mesotrione (Tenacity) Golf and sod only; residential label expected late 2009 sulfosulfuron (Certainty)

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2,4-D (many names, often with other herbicides) dicamba (Banvel)
MCPP, mecoprop (many brands)
MCPA (many) dichlorprop triclopyr (Turflon Amine, Turflon Ester) clopyralid + triclopyr (Confront) quinclorac (Drive) clopyralid (Lontrel) chlorsulfuron (Corsair) metsulfuron methyl (Manor) carfentrazone-ethyl (Quicksilver; component of Speed Zone, Power Zone) sulfentrazone (Dismiss) (component of Surge and Q4) sulfosulfuron (Certainty) mesotrione (Tenacity) Golf courses and sod only; residential label expected 2010

Dicot Weeds Controlled by Tenacity
Buttercup/Ranunculus (post)
Chickweeds (pre and post)
Clover (pre and post)
Dandelion (post)
Oxalis (post)
Speedwell species (post)
Canada thistle (post)
Sowthistle (post)

 Sulfentrazone
 Safe on most cool- and warm-season turf species
 Excellent for sedge control
 Good for annual broadleaf weeds
 Rapid activity
 Shoot and root uptake

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Sulfentrazone, with 2,4-D, MCPP, dicamba
Cool-season grasses and buffalograss
Water-based amine, low odor
For weed control when >90 F
Fast-acting (24-48 hrs)
Photosynthetic inhibitor
Dandelion, clover, oxalis, spurge, knotweed, plantain

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Quinclorac
Sulfentrazone
2,4-D (amine salt)
Dicamba (amine salt)
Excellent cool-season turf safety
Controls annual grassy weeds and long list of annual and perennial broadleaf weeds

 For use on Kentucky bluegrass, fine fescue and buffalograss lawns
 Will damage perennial ryegrass
 Low use rates: 0.125 to 0.5 oz. product/acre
 Controls ryegrass, thistle, spurge, oxalis, filaree, yarrow, kochia, knotweed, dandelion, most legumes
 Nufarm Turf and Specialty http://www.turf.us.nufarm.com/

Black medic (Medicago lupulina)
 Healthy turf
 Increase N fertility
 Preemergent control
 Gallery
 Postemergent control
 MCPP, MCPA
 Drive
 Clopyralid products

Yarrow (Achillea)
 Healthy turf
 Increase N fertility
 Preemergent control
 none
 Postemergent control
 3- and 4-way products
 Clopyralid products
VERY DIFFICULT WEED!

Bindweed (Convolvulus)
 Healthy turf suppresses it
 Increase N fertility
 Preemergent control
 none
 Postemergent control
 3- and 4-way products
 Clopyralid products
 Drive, Q4 VERY good!

 Establishes quickly
 Deep Rooted
 Resistant to conventional herbicides

http://csuturf.colostate.edu