Sugarcane Weed Identification and Control with Herbicides
Transcript of Sugarcane Weed Identification and Control with Herbicides
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Sugarcane Weed Identification and Control with Herbicides
Les Baucum
Calvin Odero
Ron Rice
North Florida Research & Education Center
Quincy, FL
November 7, 2011
What is a weed?
• Plant growing where is not wanted
• Plant out of place
• Plant that is a nuisance
• Plant that is undesirable
Weed classification
• Weeds come in all growth forms
• May be classified as
– Grass
– Grass-like (sedge)
– Broadleaf
• Forbs
• Succulents
• Shrubs
Monocots
Dicots
Helpful ID characteristics
• Morphology - structure, shape, and
orientation
– Is it a broadleaf, grass, or sedge?
– Ligule characteristics for grasses
– Inflorescence - if present can make things
easier!!
Leaf type, shape, and texture
Leaf arrangement
Alternate
Opposite
Basal Whorl
Whorled
Root type
Tap Fibrous
Inflorescence
Panicle
Spike
Umbel
Head
Vegetative reproductive structures
Tubers Stolon
Rhizome Plantlets
Monocots: grasses and sedges
Grasses Sedges (Grass-like)
Stems • Hollow or flattened
• Occasionally solid
• Nodes (jointed)
• Solid
• Triangular (3-sided)
• Without nodes
Leaves • Parallel veins
• 2 sides
• Parallel veins
• 3 sides
Flowers • Small
• Inconspicuous
• Small
• Inconspicuous
Example • Goosegrass • Yellow nutsedge
Auricles
Dicots: broadleaf plants
• Two cotyledons
• Primary root often
becomes a strong tap
root with smaller
secondary roots
• Leaves are usually
net veined and broad
at the base with a
petiole or stalk
Dicots: broadleaf plants
Forbs
Shrubs Succulents
Stems • Solid
• Pithy
• Solid
• Growth rings
• Fleshy, thick
• Sharp spines
Leaves • Net-veined • Net-veined • Small, fleshy
• Seldom present
Flowers • Small or large
• Colored
• Showy
• Small
• Showy
• Showy
Example • Common
lambsquarters
• Lantana • Cacti
Sugarcane weed control methods
• Crop competition
– Good stand, rapid & uniform growth, close-in • Shade soils and small weeds
• Mechanical
– Manual i.e. pulling, hand hoeing
– Plowing, disking
• Chemical control
– Herbicides • Soil (PRE) & foliar (POST) applied
Weeds often found in sugarcane and their
control
Crabgrass (Digitaria spp.)
• Very wide first leaf
• Initial clumping growth progressing to
prostrate, tillering
• Visible membranous ligule
• Can be very hairy, or hairless, depending
on species
Crabgrass (Digitaria spp.)
Control
• PRE – Prowl, Atrazine, Metribuzin
• POST – Asulox, Envoke or Asulox + Envoke
• Easier to control when small
Torpedograss (Panicum repens L.)
• Perennial with robust, creeping, sharply pointed rhizomes
• Leaf blade stiff and erect
• Hairs on upper and lower leaf surface
• Seedheads with stiff, ascending branches
• Occurs in wet areas
Torpedograss (Panicum repens L.)
Control
• Rhizome, buds must be destroyed for good control
• Mechanical operations that fracture rhizomes can actually result in increased populations
• Glyphosate (multiple applications) or Arsenal in noncrop areas
Fall panicum (Panicum dichotomiflorum)
• Most common grass in the area
• Relatively easy to identify
– Stem can be hairy or smooth
– Hairy when young
– Ligule fringe of hairs
– Round stem
– Widely dispersed seedhead
Control
• PRE – Prowl, Atrazine, Metribuzin
• POST – Asulox, Envoke or Asulox + Envoke
• Easier to control when small
Fall panicum (Panicum dichotomiflorum)
Wild oat (Sorghum almum)
• Not really an oat
• Closely related to
johnsongrass
– No rhizomes
– Large, membranous
ligule
– Robust plant
Wild oat (Sorghum almum)
Control
• PRE – Prowl, Atrazine, Metribuzin
• POST – Asulox, Envoke or Asulox + Envoke
• Limited experience with S. almum as a specific target
Alexandergrass & Broadleaf panicum
Broadleaf panicum (Urochloa adspersa)
• Relatively prostrate growth – Wide leaves with wavy
margins
– Round stems
– Usually dark green in color
– Very similar to alexandergrass
Broadleaf panicum (Urochloa adspersa)
Control
• PRE - Prowl, Atrazine, Metribuzin
• POST - Asulox or Envoke + Asulam
• Can be difficult
• Much easier to control when small
Alexandergrass (Brachiaria plantaginea)
• Relatively prostrate growth
• Somewhat wide leaves with straight
margins
• Round stems
• Usually light green in color
• Very similar to broadleaf panicum
– Leaves narrower (usually)
– Margins straight rather than wavy (usually)
Alexandergrass (Brachiaria plantaginea)
Control
• PRE - Prowl, Atrazine, Metribuzin
• POST - Asulox or Envoke + Asulox
• Can be difficult to control
• Much easier to control when small
Guineagrass (Panicum maximum)
• Some plants are extremely hairy, while
others are hairless
• Small plants have narrow leaves
• Becomes very large
• Highly branched seedhead
• Round stem
• Can look similar to Sorghum almum
– Sorghum almum shouldn’t be hairy
Guineagrass (Panicum maximum)
Control
• PRE - Prowl, Atrazine, Metribuzin
• POST - Asulox or Envoke + Asulox
• Need a quality surfactant to penetrate hairs
• Can be difficult to control
• Much easier to control when small
Bermudagrass (Cynodon dactylon)
• Easy to identify • Small leaves
• Rhizomes and stolons
• Mat forming
• Ligule fringe of short hairs (hard to see)
• Produces seed and spreads vegetatively
Bermudagrass (Cynodon dactylon)
Control
• PRE - Prowl can suppress from seed
• No selective POST control
• Must be controlled during fallow with multiple applications of glyphosate
Goosegrass (Eleusine indica)
• Found in many fields
• Low growing
– Very white, flattened
stems
– Looks like it has been
stepped on
– Probably not
competitive
Goosegrass (Eleusine indica)
Control
• PRE - Prowl, Atrazine, Metribuzin
• POST - Asulox or Envoke + Asulox
• Much easier to control when small
Pigweeds
(Amaranthus spp.) • Spiny amaranth is most
common – Large, upright growth
habit, entire leaves
– Very evident spines located at nodes
• Livid amaranth – Can be prostrate or erect
– Notched leaf tips
Alligatorweed (Alternanthera philoxeroides)
• Common in wet areas
of the EAA
– Often spread by
cultivation
– Low growing
• Hollow stems when
growing in wet spots
• Opposite leaves
• Small white blooms
Common lambsquarters (Chenopodium album)
• Common during the
cooler months
– Dec, Jan
• Can be difficult to
control due to waxy
leaf surface that
leaves a white-gray
color
Common purslane (Portulaca oleracea)
• Probably not competitive
• Prostrate, succulent
• Leaves small, smooth, opposite or alternate
• Red stems
• Small, yellow flowers
Common ragweed (Ambrosia artemisiifolia)
• Deeply dissected leaves
• Many hairs on upper and
lower surfaces
• Long seedhead at top of
plant
• Yellow/white flowers in
multiples
Ragweed parthenium
(Parthenium hysterophorus)
• Less common than common ragweed
– Common along canals, ditch-banks, noncrop areas
• Leaves less deeply dissected
– Divisions don’t go all the way to the stem
• White flowers
– Single, not multiples
Ragweed parthenium
(Parthenium hysterophorus)
Dayflower (Commelina spp.)
• Common in open
areas, field edges
– Small, probably not
competitive
– Prostrate growth habit
– Parallel veins on
leaves
– Actually a monocot
– Blue flowers
American black nightshade
(Solanum americanum)
• Becoming more
common in EAA
– Alternate leaves
• Usually entire
to somewhat
lobed
– Purple fruit
– Seems quite
competitive
Control of broadleaf weeds
• PRE- most can be controlled with Atrazine,
Metribuzin, and Evik
• POST - 2,4-D or Dicamba work well for most
• POST – Atrazine + Callisto works well too
• Envoke can be used for control of most
pigweeds, ragweed, and lambsquarters
• Sandea can suppress dayflower and control
spiny amaranth and common lambsquarters
Purple vs. yellow nutsedge
Purple vs. yellow nutsedge
Nutsedge control
• Can be suppressed (burned down) with
2,4-D or 2,4-D in combination with Evik
• Envoke, Sandea, and Yukon provide
excellent systemic control
Herbicide program: plant cane
• Fallow
– Start with clean, weed free field – 2 to 3
applications of glyphosate during the fallow
period
– Prior to planting, disk until soil is well worked
• Successive
– Multiple diskings until soil is well worked
Herbicide program: plant cane
• PRE
– Prowl + Atrazine
• Prowl = Prowl H20 : muck soils = up to 8.4 pts/acre;
otherwise 6.2 pts/acre)
– No POST activity; apply shortly after planting
– Will need to be incorporated into the soil (preferably by
rain or irrigation
• Atrazine 4L = 4-8 pts/acre/application
• Atrazine 90DF = 2.2-4.4 lbs/acre/application)
• POST
– Atrazine + 2,4-D (or Dicamba, or 2,4-D Dicamba mix)
Herbicide program: stubble cane
• PRE
– Prowl + Atrazine
• Prowl = Prowl H20 : muck soils = up to 8.4 pts/acre;
otherwise 6.2 pts/acre)
– No POST activity; apply shortly after harvest
– Will need to be incorporated into the soil (preferably by
rain or irrigation
• Atrazine 4L = 4-8 pts/acre/application
• Atrazine 90DF = 2.2-4.4 lbs/acre/application)
• POST
– Atrazine + 2,4-D (or Dicamba, or 2,4-D Dicamba mix)
Thank you