Rice Weed Identification

Rice Weed
Identification
Louisiana Agricultural
Technology and
Management Conference
February 8, 2007
Johnny Saichuk
Keying Out vs Recognizing Plants
• Taxonomists use floral parts
– Least affected by environment
– Lots of differences
• Agriculturists use vegetative parts
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Cannot wait until reproductive state
Fewer and more subtle differences
May be affected by environment
Restricted to fewer plants
Typical Grass Spikelet
awn of lemma
anthers
stamen
filament
palea
stigmas (2) of pistil
Lemma (fertile)
ovary of pistil
inner glume
outer glume
Typical Dicot Flower (1)
stamens
filaments
anthers
stigmas and styles
of pistil
Typical dicot flower (2)
c
o
r
o
l
l
a
petals
perianth
sepals
calyx
Diagnostic Grass Parts
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Ligules
Auricles
Leaf tips
Appearance of youngest leaf
Stolons and/or rhizomes
Seeds
Examples of Grass Ligules
none
row of
hairs
membrane
fringed
with hairs
short
membrane
long
membrane
auricles
blunt leaf tip
tapered leaf tip
Appearance of Youngest Leaf
Rolled in bud
Folded in bud
Stolon of Rice Cutgrass
(Leersia oryzoides)
Rhizomes of Torpedograss
(Panicum repens)
Crown buds of Creeping Rivergrass
(perennial barnyardgrass) – Echinochloa
polystachya
Echinochloa sp.
Panicum sp.
Barnyardgrass
Echinochloa crus-galli
Mannagrass
Glyceria declinata
Rice Cutgrass
Leersia oryzoides
Neally Sprangletop
Leptochloa nealleyi
Amazon or Tighthead Sprangletop
Leptochloa panicoides
Red Sprangletop
Leptochloa filiformis
Mexican Sprangletop
Leptochloa uninerva
Fall Panicum
Panicum dichotomiflorum
Torpedograss
Panicum repens
Brook Paspalum or Canoegrass
Paspalum acuminatum
Knotgrass
Paspalum distichum
Water Paspalum
Paspalum hydrophilum
Diagnostic Broadleaf Parts
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Leaf margins
Leaf arrangement
Leaf attachment
Leaf shape
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Leaf types
Stem properties
Flower arrangement
Specialized parts
Texasweed
Copperleaf
Caperonia palustris
Acalypha ostryifolia
serrate leaf margins
Alligatorweed
Toothcup
Alternanthera
philoxeroides
Rotala ramosior
Purple Ammania
Toothcup
Ammania coccinea
Rotala ramosior
Arrowhead
Sagittaria sp.
Burhead
Echinodorus cordifolius
Ducksalad
Heteranthera limnosa
Roundleaf Mud
Plantain
Heteranthera reniformis
Eclipta
Creeping Spotflower
Eclipta prostrata
Spilanthes americana
antrose pubescence
sparse pubescence
septate stem
ocrea
septae
stipule
pinnately
compound
leaf
1st true
leaf
cotyledons
2nd true
leaf
Hedge Hyssop
Gratiola neglecta
peduncles
G. virginiana
spatulate floating leaves
filiform submersed leaves
Water Starwort Callitriche heterophylla
Ducksalad, Heteranthera limnosa
Smartweed
Polygonum sp.
Jungle Rice,
Echinochloa colonum
anthocyanin pigment
A Schematic Diagram for Seedling Weed Identification in Rice
Pickerelweed
Round-leaf
Mud plantain
Characteristics of Grasses
Long petiole
& ovate leaf
Ligules
Long petiole
& linear leaf
Ducksalad
A triad of 3
fleshy leaves
Common
arrowhead
Straplike leaves
& milky juice
Spreading
dayflower
Long slim leaves (8-26 cm)
Peruvian watergrass
Short leaves (2-3 cm)
Southern watergrass
Hollow stem with prominent leaf midvein
Water paspalum
Solid stem with hair at collar region
Knotgrass
Solid stem without hair at collar region
Brook paspalum
Long membranous ligule
Grass-like
wide leaves
Membranous ligule
Aquatic spp. etc
Short membranous ligule
Rhizomes present
Auricles
Monocots
Cotyledons absent or
parallel veins on leaves
perennial
grasses
Wide or thick
fleshy leaves
Hairy ligule (yellow)
Creeping river grass (perennial barnyardgrass)
Grass-like
Purple bands on leaves
Junglerice
No purple bands on leaves
Barnyardgrass
Ligules absent
Annual
grasses
Rhizomes absent
Ligules present
Leaves grow in
3 directions
Mid veins
Seedling Weeds in rice
Green leaf 3-6 mm wide
Mid-vein prominent
leaf surface glabrous
Rice flatsedge
Dark green leaf 1-2 mm wide
Annual sedge
Sedges
Characteristics of Sedges
Leaf tip abruptly tapering
Purple nutsedge
Leaf tip gradually tapering
Yellow nutsedge
Fall panicum
Narrow membrane
fringed with hairs
Tuber absent
Tuber present
Mid-vein not prominent
leaf surface pubescent
Broadleaf signalgrass
Mid-vein prominent
Amazon sprangletop
Long membrane
Large clasping auricles
Red rice
Mid-vein not prominent
No auricles
Leaves 3-ranked
Cotyledons present or
leaves with net-like veins
Dicots
Triangular stem
Perennial
broadleaves
From vegetative parts
Hollow stems
Bearded sprangletop
Alligatorweed
Cotyledons linear to lanceolate
Seedling reddish and glabrous
Purple ammannia
Cotyledons lance-shaped
Cotyledon tip acute
Pale smartweed
No purple mark on leaves
Ladysthumb
Purple marks on leaves
Pennsylvania smartweed
Cotyledon tip obtuse
Characteristics of Broadleaves
Cotyledon shapes
Annual
broadleaves
From seeds
Stems and petioles coarsely hairy
Texasweed
Leaf serrate with long petiole
Redweed
Cotyledons orbicular
Leaf types
Cotyledons lanceolate
Stems smooth with indented leaves
Cotyledons spatulate
Cotyledons oblong
Leaves alternate & pinnate
Leaf remotely toothed w/o petiole
Eclipta
1st true leaf entire
Hemp sesbania
1st true leaf pinnate compound
Created by: Wei Zhang and Eric P. Webster
Characteristics drawn by:
Cutleaf groundcherry
Indian or rough jointvetch
Johnny Saichuk
1373 Caffey Rd.
Rayne, LA 70578
[email protected]
Office: 337-788-7547
Cell: 337-849-6253
Fax: 337-788-7568