Download Weed Management

Weed Management:
A Basic Approach
Ken Hutto, Ph.D.
West Florida Research and Ed. Center
University of Florida-IFAS
Developing a Weed Management
Program
• Prevent weed introduction
• Properly maintain turfgrasses
• Identify weeds and learn life cycle
• Application timing is crucial!!
• Initiate control practices
– Cultural
– Mechanical
– Herbicides
Back to Basics Approach
• Cultural Practices
– Fertility
– Water management
• Irrigation
• Drainage
– Mowing
• Height
• Frequency
– Control other pests
Fertility
– 1 lb/yr
– 2 lb/yr
– 3 lb/yr
Crabgrass
Relative Density
• Avg density (%)
weeds
• N applied at:
Dandelion
100
75
50
25
0
1
2
LB N/YR
Coats et al. Mississippi State University
Photo: turf.ufl.edu
3
Weed Management –
Putting It All Together
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Fertility
Irrigation
Mowing
Cultivation
Insects
Diseases
Weed cycles
Key is --Competition
Competition
Competition
Weeds can be indicators of other
problems…
Low pH
High pH
Compacted Soil
Poorly Drained Soils
Low N
Nematodes
Addressing the Problem
• Presence of a weed does not
necessarily mean there is a secondary
problem
– Spurge and nematodes
• Killing the weed does not necessarily
cure the problem
– Nutsedge and poor drainage
Types of Weeds
Broadleaf Weeds
• Dicot
• Netted veins
• Wide leaf blade
– Opposite
– Alternate
– Whorled
• Generally erect
growth
• Can have showy
flowers
Grass Weeds
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Monocot
Parallel veins
Thin leaves
Fibrous root system
Round, oval or flat
stem
• Seed head
Grass-Like Weeds
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Monocot
Parallel veins
Thin leaves
Round, hollow
stems
• Triangular stems
• 3-ranked leaves
• Can produce above
ground fruit
– Bulbils on wild onion
Weed Management Strategy
• Diagnose problem
– Weed ID
– Is the problem something else?
• Evaluate control methods
– What are your options?
– Is problem worthy of investing time and money?
• Select program
• Execute program
• Evaluate
– Did program work?
Winter Weeds
Annual bluegrass
• Winter annual
• Pale green color
• Boat-shaped leaf
tip
• Bunch-type growth
habit
• Produces many
seedheads
– Can flower
throughout life
cycle
Perennial ryegrass
• Can become a
weed during spring
transition
• Round stem
• Glossy appearance
• Bunch-type growth
• Red/maroon color
at base
Wild garlic
• Winter grass-like
perennial
• Emerges fall/early
winter
• Round, hollow
stem
• Parallel veins
• Garlic odor
• Underground
bulbs
Annual blueeyed-grass
• Winter annual
• Leaves flat,
clustered at base
• Pale purple/white
flower
• Found in moist
areas
Common chickweed
• Winter annual
• Can form dense
mats
– Many branches
• Leaves opposite;
entire (smooth
margins); ovalshaped
• Small white
flowers in clusters
at end of stems
Mouseear chickweed
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Winter annual
Leaves opposite
Oval shape
Densely hairy
– Leaves and stems
• White flowers at end
of stem
Henbit
• Winter annual
• Square, purple stem
– Mint family
• Leaves opposite
– Toothed margins
• Purple flower with
distinct lower petal
– “Lip-like” petal
White clover
• Winter perennial
broadleaf
• Trifoliate leaves
– Three leaflets make up
one leaf
– White band at base
– Margins slightly toothed
• White flowers
• Can persist into
summer if conditions
are suitable
Lawn burweed
spurweed or stickerweed
• Winter annual
• Leaves opposite
– Highly lobed (divided)
– Looks like many tiny
leaves
• Mat-forming
• Produces spines in
spring
Dandelion
• Perennial
• Reproduces by seed;
can form new plants
from taproot segments
• Leaves basal, deeply
lobed pointing back
• White, plume seed
head
• Yellow flower
Summer Annual Grass Weeds
Southern crabgrass
• Ligule: tall, membranous
• Sheath: oval
• Pubescence: dense
– On top and bottom of leaf
blade
– On leaf sheath
– Longer pubescence around
collar region
• Produces short, fat 1st true
leaf parallel to soil surface
Pictures copied from www.ppdl.purdue.edu
Goosegrass
• Ligule: short,
membranous
• Sheath: flat
– White longitudinal lines
• Pubescence: long
scraggly hairs near
sheath
– Can be variable
• White-gray base
Pictures copied from www.agronomy.lsu.edu and www.agriculture.org
Crowfootgrass
• Ligule: short, ciliate
membranous
• Sheath: flat
• Pubescence: evenly
spaced hairs on leaf
margin (when small)
Pictures copied from www.agronomy.lsu.edu
Southern sandbur
• Ligule: short, ciliate
• Sheath: flat
• Leaf blade: scabrous
margins
– Leaf blade can turn purple
– Compressed near sheath
• Pubescence: may have
short, stiff hairs near
sheath
Pictures copied from www.clemson.edu and www.agriculture.org
Yellow foxtail
• Ligule: short, ciliate
• Sheath: flat
• Pubescence: long,
scraggly hairs on bottom
third of leaf
• Can produce red color at
base of plant
Pictures copied from www.ppws.vt.edu
Perennial Grass Weeds
Torpedograss
• Ligule: ciliate
• Sheath: round
• Leaf blade:
– Very stiff erect growth
• Pubescence:
– top of leaf
– margins
– Collar region
• Produces massive rhizome
system
Pictures copied from www.lsuagcenter.com
Dallisgrass
• Ligule: tall,
membranous
• Sheath: Oval to flat
• Pubescence: variable
– Dense when small
– Mature plants: around
collar region
Bahiagrass
• Ligule: tall, membranous
• Sheath: round
• Leaf blade: flat or folded
• Pubescence: glabrous
– May have few hairs around
collar region
Summer Grass-Like Weeds
Purple nutsedge
• Tuber forming
– Tubers connected by
chains
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Triangular stem
Three-ranked leaves
Blunt leaf tip
Pepper smell
– Bitter taste
Yellow nutsedge
• Tuber forming
– Tubers not connected by
chains
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Triangular stem
Three-ranked leaves
Tapered leaf tip
Camphor smell
– Sweet taste
Purple vs. Yellow Nutsedge
Kyllinga sp.
• Annual sedge
reproducing seed
– No tubers
– High density
• Triangular stem
• Three-ranked leaves
– Have distinct midvein
• Globular seedhead
– Three distinct leaves
below seedhead
Summer Broadleaf Weeds
Virginia buttonweed
• Summer perennial
broadleaf
• Elliptical shaped leaves
– Opposite
• Leaf margins scabrous
• Vegetative reproduction
- fleshy root
• Seeds look like small
pumpkins
Florida pusley
• Prostrate and spreading
summer annual
• Has branched, hairy
stems
• Leaves opposite, oval
shaped
• Tubular, white flowers
clustered in the
terminal of plant
• Reproduces by seed
Old World Diamond-flower
• Summer annual with
branched stems
• Leaves opposite
and narrow
• Flowers white
– Usually two or more
on one long stalk
• Reproduces by seed
Florida betony
• Erect growth
• Leaves:
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Opposite
Lance-shaped
Margins lobed
Flat base
• Stem:
– Square
• Large, white tubers
– Rattlesnake weed
Chamberbitter
• Erect growth
• Leaves:
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Alternate
Thin
Smooth margins
Oblong
Compound
• Stem:
– Erect, angled
• Produces fruit and flowers
on underside of leaf
Dollarweed
• Perennial
• Established from
rhizomes
• Leaves round with
long petioles
• Reproduces by
seed, rhizomes and
tubers
• Thrives in wet areas
Dichondra
• Creeping perennial
• Roots at nodes
• Leaves alternate,
kidney-shaped
• Reproduces by seed
and stolons
Yellow woodsorrel
• Herbaceous
perennial with hairy
stems
• Alternate leaves
– Divided into three
heart-shaped lobes
• Has a narrow “okralike” seed capsule
• Small, yellow flower
• Can be mistaken for
clover
Prostrate spurge
• Summer annual
– Prostrate growth habit
• Leaves opposite
• Hairs on stems lay flat
– Stems have milky sap
– Roots at nodes
• Three-lobed fruit
• Reproduces by seed
Current Weed Control Options
for St. Augustinegrass and
Centipedegrass
Certainty - Monsanto
• Sulfosulfuron, 75 WDG
• Sulfonylurea herbicide
• Rate: 0.75 to 1.25 oz/ac (max of 2.66 oz
per year)
Certainty - Monsanto
• Tolerant species:
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Bermudagrass
St. Augustinegrass
Centipedegrass
Zoysiagrass
Seashore Paspalum
Certainty - Monsanto
• Weeds on label:
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yellow and purple nutsedge
kyllinga
Poa annua
chamberbitter
chickweed
white clover
henbit
Certainty- Monsanto
• Spring transition aid
– may require 2 applications
QuickSilver - FMC
• Carfentrazone – 1.9 SC
• Postemergence broadleaf control
• For use on golf courses, commercial,
residential turf
• 0.55 to 2.1 fl oz/A
• Rapid activity
• No grass control
QuickSilver
• Safe on turf species
– Bermudagrass
– St. Augustinegrass
– Centipedegrass
– Zoysiagrass
– Bahiagrass
– Seashore Paspalum
– Perennial Ryegrass
QuickSilver
• Newly seeded, sodded, or sprigged turfgrass
– 7 days after emergence
• Bermudagrass
• St. Augustinegrass
– 14 days after emergence
• Zoysiagrass
QuickSilver
• Weeds on label:
– Virginia buttonweed
– Lawn burweed
– Florida pusley
– Chickweed
– White clover
– Spurge
– Henbit
– Purslane
– Thistle
Aim - FMC
• Carfentrazone – 1.9 SC (same active
ingredient as QuickSilver)
• Postemergence broadleaf control
• For use in warm-season sod
production
• 0.55 to 2.1 fl oz/A
• Rapid activity
• No grass control
New Herbicides
• Dismiss
• Octane SC
Dismiss - FMC
• Sulfentrazone – 4F
• Postemergence
• Sod production, commercial,
residential, athletic fields, golf
course fairways and roughs
• Very rapid activity
• No grass control
Dismiss
• Tolerant Turf Species:
– Application Rate = 8 oz/A
• Bahiagrass
• Centipedegrass
• Seashore Paspalum
• Zoysiagrass
Dismiss
• Tolerant Turf Species:
– Application Rate = 12 oz/A
• Bermudagrass
Dismiss
• Weed listed on label:
– Sedge Species including –
• Kyllinga species
• Purple nutsedge
• Yellow nutsedge
Dismiss
• Weed listed on label:
– Broadleaf Species including –
• Black medic
• Carolina geranium
• Chickweed
• Clover
• Cudweed
• Henbit
• Florida pusley
• Spurge
• Wild garlic
• Yellow woodsorrel
Octane SC
• New herbicide from SePRO Corporation
Octane SC
(pyraflufen ethyl)
• Labeled for:
– Bermudagrass
– Centipedegrass
– St. Augustinegrass
– Zoysiagrass
Octane SC
(pyraflufen ethyl)
• Weeds Listed on Label:
– Hairy beggartick
– Carpetweed
– Chickweed
– White clover
– Curly dock
– Cutleaf eveningprimrose
– Knotweed
– Common purslane
“New” (Old) Herbicide
• Sedgehammer
Gowan Company
• Sedgehammer (halosulfuron)
– Formerly Manage
– Nutsedge control in golf courses,
residential, commercial turf and
ornamentals
– Same formulation, uses, rates as Manage
“New” (Old) Herbicide
• Sandea
–Gowan Company
Gowan Company
• Sandea (halosulfuron)
– Formerly Permit/Manage
– Nutsedge control in turf for sod
– Same formulation, uses, rates as
Permit/Manage
“New” Herbicides
• Generic PREs
– Proclipse (NuFarm)
– Resolute (Syngenta)
– Cavalcade (Sipcam)
– Stonewall (Lesco)
– Quali-Pro products
– Etc.
“New” Herbicide
• Vantage – sethoxydim
– Now sold as:
• Southern Ag Grass Killer contains
VANTAGE
• Sethoxydim G-PRO from Gro-Pro LLC
Other Options
• Manor
– POST broadleaf
– Bahiagrass
• Spotlight
– POST broadleaf
• Image
– Some POST broadleaf
– Sedge
Products on the Shelf
Preemergence
• Green Light Amaze®
– benefin + oryzalin
• Scotts Halts ®
– pendimethalin
Non-Selective
• Roundup®
• Many products
containing:
• Sta-Green Crab-Ex™
– glyphosate
– diquat
– fluazifop
– dithiopyr
• Many others
– PRE weed and feed
Products on the Shelf
POST Broadleaf
• Many products
containing**:
– 2,4-D
– mecoprop (MCPP)
– dicamba
– dicloprop
• sulfentrazone
• Image
– imazaquin
• Many products
containing atrazine
POST Grass (Sidewalks)
• Products containing:
– fluazifop
– imazapic
• Ortho® Season Long
Grass and Weed Killer
– oxyfluorfen + glyphosate
POST Sedge
• Image
**Most products containing these active ingredients are not labeled for
St. Augustinegrass or centipedegrass.
Things to Watch Out For…
• Timing of weed-and-feed products.
• “Do not apply to any improved variety…”
– Not every product stating “for St.
Augustinegrass” can be used on widely used
varieties.
• Some products are not what they seem.
– Image (imazaquin)
– Image with Atrazine (atrazine…no imazaquin!!)
Message for End Users…
• Always read the label, AND APPLY
CORRECTLY!
• Always obey safety precautions
– Personal protective equipment
• Be aware of environmental conditions
• Promote managing turfgrass first
• Offer your services!
Questions?