Transcript Mechanical Weed Control

Weeds
What
is a weed?
–A weed is a plant out of place
Neal and Carrawan 2004 NC State Univ
What Do Weeds Do?
 Compete with crops for
resources
 Interfere with crop quality and
quantity
 Reduce aesthetics of landscape
 Affect function of turfgrass
 Displace native flora
Neal and Carrawan 2004 NC State Univ
What Do Weeds Do?
Cause
allergies
Harm people
Harbor insects and
plant pathogens
Neal and Carrawan 2004 NC State Univ
Ragweed
pollen causes
hay fever
Weeds -- How Did They Get There?
 Every
shovel full of soil contains
thousands of weed seeds -waiting for an opportunity
 Often we just provide the weeds
with the opportunity and
environment to flourish
Neal and Carrawan 2004 NC State Univ
Weed Seed Are Spread By:
 Wind
 People
 Rain
runoff
 Birds and
other animals
Neal and Carrawan 2004 NC State Univ
 Garden
cultivation
 Mowing
 Topsoil or
compost
addition
 Purchased
plants
Invaders - weed dispersal
Wind
Surface
water
Birds & animals
Activities of man
–site prep, cultivation, planting
Neal and Carrawan 2004 NC State Univ
How we introduce
and move weeds
–top soil
–organic amendments
–equipment
–plants
Neal and Carrawan 2004 NC State Univ
And, sometimes we
intentionally introduce
weeds
Multiflora
rose
Crabgrass
Kudzu
Neal and Carrawan 2004 NC State Univ
More Plants (weeds) Intentionally
Introduced
Water
hyacinth
Bamboo
Japanese knotweed
Neal and Carrawan 2004 NC State Univ
The First Step in Weed
Management is Identification!
Weed Identification – Its More
Than Knowing a Name!
Neal and Carrawan 2004 NC State Univ
Why is it Important to Identify
Weeds?
 So you know
–when it germinates,
–how it spreads,
 And,
so you can determine
the most appropriate control
measure(s) -- herbicides,
cultivation, mulches, etc.
Neal and Carrawan 2004 NC State Univ
How do you correctly identify a weed?
 Compare
to a photo
– Remember weeds can appear
different due to site conditions
– Easiest to do when plant is
flowering
 Keys
to Identification
 Send a sample to the local
Cooperative Extension
office
Neal and Carrawan 2004 NC State Univ
Identification Resources
 For Piedmont and Coastal
Plains
–Identifying Seedling and Mature
Weeds in the Southeastern US
–Weeds of Southern Turfgrass
 Mountains
–Weeds of the Northeast
–Weeds of Southern Turfgrass
Neal and Carrawan 2004 NC State Univ
How to order:
 Identifying
Seedling and Mature
Weeds in the Southeastern US
(AG-208)
– Publications Office, Box 7603
NCSU, Raleigh, NC 27695-7603
$10.00
Neal and Carrawan 2004 NC State Univ
How to order:
 Weeds
of Southern
Turfgrass
– Publication Distributions
Center
IFAS Building 664
P. O. Box 110011
University of Florida
Gainesville, FL 32611
(352-392-1764) $8.00 + $3.00
shipping
Neal and Carrawan 2004 NC State Univ
How to order:
 Weeds
of the Northeast
– Cornell University Press
P. O. Box 6525
Ithaca, NY 14851-6525
607-277-2211
$29.95 plus $5 shipping
Neal and Carrawan 2004 NC State Univ
Some Web-Based Weed ID Resources
www.ces.ncsu.edu/depts/hort/weeds
 www.ppws.vt.edu/weedindex.htm
 www.rce.rutgers.edu/weeds/
 axp.ipm.ucdavis.edu/PMG/weeds_common.
html
 www.psu.missouri.edu/fishel/
 www.ppws.vt.edu/newss/weedid.htm
 www.griffin.peachnet.edu/cssci/TURF/turf.
htm

Neal and Carrawan 2004 NC State Univ
How to send a sample for ID
Fresh
samples: moisten
sample; wrap in DRY paper
towel; put in a zip-lock bag
and mail on Monday or
Tuesday to the appropriate
specialist
Neal and Carrawan 2004 NC State Univ
How to send a sample for ID
 If
you cannot send it right away
(or if you get the sample on
Thursday or Friday: Lay flat on
between newspaper; press.
 Mail the dried, pressed sample
to the appropriate specialist
Neal and Carrawan 2004 NC State Univ
Use the Sample Submission Form
 http://intra.ces.ncsu.edu/depts/cs
/weedforms/2weedide.pdf or
 http://www.cropsci.ncsu.edu/turff
iles/weedid/weedid.htm
 http://www.cropsci.ncsu.edu/aqu
aticweeds/weed_id/aquatic.htm
Neal and Carrawan 2004 NC State Univ
Classification of Weeds
Neal and Carrawan 2004 NC State Univ
Weed Classification
Ways
weeds are classified
–Lifecycle
–Seed leaves
–Growth habit
–Susceptibility to herbicides
Neal and Carrawan 2004 NC State Univ
Lifecycles
Annual
Biennial
Perennial
Neal and Carrawan 2004 NC State Univ
Life cycle of an annual weed
Plant
dies
Seed
Plant
sets
seed
Neal and Carrawan 2004 NC State Univ
Seedling
Plant
flowers
Life cycle of a winter annual weed
Plant
dies
Summer
Fall
Seed
Plant
sets
seed
Neal and Carrawan 2004 NC State Univ
Seedling
Plant
flowers
Common
winter
annual
weeds
Neal and Carrawan 2004 NC State Univ
Life cycle of a summer annual weed
Plant
dies
Spring
Fall
Seed
Plant
sets
seed
Neal and Carrawan 2004 NC State Univ
Seedling
Plant
flowers
J. Derr
Common Summer Annual Weeds
Neal and Carrawan 2004 NC State Univ
Life cycle of a biennial weed
Plant
dies
Plant
sets
seed
Seedling
Seed
Second
Season
Plant
flowers
Neal and Carrawan 2004 NC State Univ
First
Season
Overwinters as
a rosette
Common Biennials
Neal and Carrawan 2004 NC State Univ
J. DiTomaso
R. Uva
Thistle
Queens Ann’s Lace
Mullein
J. Neal
Bull
Life cycle of a perennial weed
Roots/
rhizomes
spread
Seed
Seedling
Plant
Over-winters
New plant
Neal and Carrawan 2004 NC State Univ
Plant
Flowers
Plant
sets
Seed
Some common perennial weeds
Neal and Carrawan 2004 NC State Univ
Perennial Weeds
Reproduce By:
Seeds
Tubers
Bulbs
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Stolons
Rhizomes
Types of Perennial Weeds
 Simple perennials
 Creeping perennials
–Rhizomes
–Stolons
–Creeping roots that produce
shoots
 Tuberous
perennials
 Bulbous perennials
Neal and Carrawan 2004 NC State Univ
Simple Perennials
 Spread
by seed
 Tap root or hardy
fibrous root system
 Examples:
dandelion, plantain,
dogfennel,
pokeweed
Neal and Carrawan 2004 NC State Univ
Tap root
Creeping Perennials
 Reproduce
Stolon
and spread by
– Underground stems (rhizomes)
– Above-ground stems (stolons)
– Creeping fleshy roots that Rhizome
produce new shoots
 Many
also reproduce by
seeds or other means.
Neal and Carrawan 2004 NC State Univ
Tuberous
Perennials
 Tubers
are swollen,
modified stems that are
often resilient to controls,
spread by cultivation,
and may persist in the
soil for years.
 Tubers form on rhizomes
Neal and Carrawan 2004 NC State Univ
Tubers
Bulbous Perennials
 Persist
through the
dormant season as a
bulb
 Wild garlic and
wild onion produce
bulblets, aerial bulblets,
and seeds
Neal and Carrawan 2004 NC State Univ
Weeds Are Also Classified By:
Cotyledons
Monocot
(one seed leaf)
Neal and Carrawan 2004 NC State Univ
(Seed leaves)
Dicot
(two seed leaves)
Monocots
 One
seed leaf when
plant emerges
 Long narrow leaves
 Parallel veins
Neal and Carrawan 2004 NC State Univ
Monocots -- Examples
 Grasses
 Sedges
 Onions
 Rushes
 Garlic
 Lilies
 Dayflower
Neal and Carrawan 2004 NC State Univ
Grasses
 Rounded
or flattened stems and
nodes
 Have fibrous root systems
 Some have fibrous roots,
rhizomes or stolons for
reproduction
 Growing point is below surface
Neal and Carrawan 2004 NC State Univ
seedhead
blade
Grasses are
identified
by:
sheath
ligule
auricles
midrib
stolon
collar
bud leaf
crown
rhizome
Neal and Carrawan 2004 NC State Univ
Vernation or Leaf Bud
Rolled in the bud
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Folded in the bud
Ligules
Absent
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Membranous
Hairy
Ligules
Absent
Neal and Carrawan 2004 NC State Univ
Membranous
Hairy
Auricle
Absent
Neal and Carrawan 2004 NC State Univ
Present
Clasping
Panicle
Neal and Carrawan 2004 NC State Univ
Branched spike
The Scotts Co.
The Scotts Co.
The Scotts Co.
Seedheads
Spike
Seedheads
Panicle
Neal and Carrawan 2004 NC State Univ
Branched spike
Spike
Grass-Like Weeds
 Sedges:
Sedges have triangular
“stems”. Grasses have flat or rounded
“stems”.
– Annual and perennial species
– Most common and difficult to control
are yellow and purple nutsedge
 Wild
Garlic and wild onion: hollow
leaves have a pungent onion-like or
garlic-like aroma
– Wild garlic is the most common
Neal and Carrawan 2004 NC State Univ
Grass-like, but “Sedges
have edges” – triangular
“stems”
 Leaves emerge 3-ranked
 Spread by rhizomes and
over-winter as tubers
 Tubers often introduced
in top soil

Neal and Carrawan 2004 NC State Univ
A. Senesac
Yellow and Purple
Nutsedges (Cyperus spp.)
Yellow Nutsedge
(Cyperus esculentus)
Perennial with
rhizomes and tubers
 Emerge in late spring;
die in the fall
 “Daughter” plants
and tubers formed at
tips of rhizomes
 One plant can form as
many as 6000 tubers

Neal and Carrawan 2004 NC State Univ
PurpleNutsedge
(Cyperus rotundus)
Rhizomatous and
tuberous perennial
 Emerge in midspring; die in the fall
 Forms tubers within
6 weeks of
emergence
 Very hard to control
 The “world’s worst
weed”

Neal and Carrawan 2004 NC State Univ
Forms tubers in
“chains”
Yellow vs. Purple – Leaf tips
Yellow
nutsedge
leaf tips
taper to a
long,
narrow
point
Neal and Carrawan 2004 NC State Univ
Yellow
Purple
Purple
nutsedge
leaf tips
are
pointed
but not
tapered
Yellow vs. Purple -- Flowers
Purple Nutsedge
Yellow
Nutsedge
Purple or reddish
brown turning black
Yellow fading to tan
Neal and Carrawan 2004 NC State Univ
Wild Garlic (Allium vineale)
Bulbous
perennial
 Strong scent
 Reproduces by
bulblets, rarely
by seed
 Emerges in the
winter and dies
back in late
spring or early
summer

Neal and Carrawan 2004 NC State Univ
Aerial
bulblets
Dicots or Broadleaf weeds
 Two
seed leaves (cotyledons)
 Leaves have netted veins
 Largest group of weeds
 Often with bright showy
flowers
 Exposed growing points
Neal and Carrawan 2004 NC State Univ
How to ID Dicots
Flowers
Unique
Characteristics
Growth Habit
Leaf Orientation, Shape, Etc.
Neal and Carrawan 2004 NC State Univ
Unique Characteristics
 Look
for:
–Thorns or spines
–Square or winged stems
–Compound leaves
–Whorled leaves
–Milky sap
Neal and Carrawan 2004 NC State Univ
J. Neal
J. Neal
Growth Habits
Upright
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Spreading
Leaf Orientation
Opposite
Whorled
Alternate
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Rosette
Simple Verses Compound Leaves
Pinnate
Simple
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Palmate
Compound
Other Ways to Identify Cont.
 Leaf
shape
 Leaf margin
–Toothed,entire,lobed, or deeply
cut
 Petiole
length
 Hair on leaves or other parts
Neal and Carrawan 2004 NC State Univ
Leaf Shapes, tips & bases
Neal and Carrawan 2004 NC State Univ
Leaf Margins
Shallow
lobes or
toothed
J. Ditomaso
Entire
Deeply
lobed
Neal and Carrawan 2004 NC State Univ
Hairs –
present or absent, & where?
Mouseear chickweed -Hairs on stem & leaves
Neal and Carrawan 2004 NC State Univ
Common chickweed -Hairs absent
Tell Me What You See?
Neal and Carrawan 2004 NC State Univ
Tell Me What You See?
 Rosette
 Broad,
nearly
entire leaves
 5 veins
 Flowers on
spikes
Broadleaf plantain
Neal and Carrawan 2004 NC State Univ
L. Clark
Tell Me What You See?
Neal and Carrawan 2004 NC State Univ
Tell Me What You See?
L. Clark
 Alternate
Neal and Carrawan 2004 NC State Univ
leaves
 Deeply divided
(dissected)
leaves. Twice
lobed.