Transcript IPM for Weeds - San Diego Master Gardeners

IPM for Weeds
University of California
Statewide IPM Program
In this presentation….
• Definition of IPM
• Tips on ID and biology
Cultivation
• Trouble
weeds
• Management
• Prevention
Competitive plants
Mulches
IPM for Weeds
Why manage weeds?
People don’t like the way weeds look
• Crowd out desirable plants
• Provide hiding places for
pests
Bee stings
Burclover
Tripping or
fire hazards
IPM for Weeds
What is IPM?
• Science-based
• Combines several pest
management methods
• Focuses on long-term
prevention
• Pesticides used as a last
resort
• Keeps weeds at a level
you can live with
• You set your own goals
Weed management
with IPM
Didn’t plan ahead
IPM for Weeds
How do you identify weeds?
Broadleaves
Wide
leaves
Branching veins
Dallisgrass
Sedges
Yellow
Leaves
nutsedge
in sets
of 3
Triangular
stems
Oxalis
Grasses
Narrow
leaves
Large
crabgrass
Arranged
in sets of 2
Parallel
veins
Round or
flat stems
IPM for Weeds
Want more information
on weed ID?
• ID weed to species for most effective
management approach
Weed
photo
gallery
www.ipm.ucdavis.edu
Pest
notes
Key to
weeds
in lawn
IPM for Weeds
What makes some plants
successful as weeds?
• Competitive and invasive
• Reproduce quickly
Tubers
Seeds
Rhizomes
Stolons
IPM for Weeds
Why are weeds invading?
• Poorly maintained areas
• Underlying problem
IPM for Weeds
Why are weeds invading?
Maintenance problem
Overwatered or
Nutsedge
waterlogged
flower
areas
Annual
bluegrass
Crabgrass
Nutsedge
IPM for Weeds
Why are weeds invading?
Knotweed
Maintenance problem
Compacted
soils or bare
areas
Spotted spurge
IPM for Weeds
Why are weeds invading?
Maintenance problem
Lawns low in
nitrogen
fertilizer
White clover
Black medic
Burclover
IPM for Weeds
Why are weeds invading?
Dandelion
Maintenance problem
Thin areas in
lawns
IPM for Weeds
Why are weeds invading?
Maintenance problem
Lawns mowed
too short
Bermudagrass
flower head
Invading
Bermudagrass
IPM for Weeds
Know the life cycle of your weed
Control weeds before they spread
Annual
bluegrass
Annual weeds
Crabgrass
Die
Sprout
Sowthistle
Grow
Flower
Spotted spurge
IPM for Weeds
Know the life cycle of your weed
Control before vegetative parts or seeds form
Perennial weeds
Bermudagrass
Grow
Overwinter
Oxalis
Mature
Die
back
IPM for Weeds
When should weeds be
managed?
• Before you plant, before weeds emerge,
and before weeds mature
Before planting
Seed dispersal
• Prepare site
Don’t let
Seed
Before emergence
weeds go
• Plant competitive
to seed or
species
develop
• Apply mulch
vegetative
Seedling
parts!
Emergence
• Cultivate
Flower
Maturing
development
• Mow
weed
IPM for Weeds
Get weeds out before
you plant
• Dig out existing vegetation
• Cultivate, irrigate, cultivate
• Solarize
the soil
• Apply a
nonselective
herbicide for
serious weed
problems
IPM for Weeds
Give your plants a head start
Soils
• Must hold water and nutrients
• Must have good drainage
• Amend soil before planting
Plants
• Establish quickly
• Choose vigorous plants
adapted to local conditions
• Plant ground covers to cover
bare areas
IPM for Weeds
Prevent weeds with mulches
Mulch: layer of material
put on the soil surface
around plants to prevent
weed growth
• Block light and
suppress weed
growth
• Hold moisture in;
reduce soil
compaction and
erosion
• Improve soil
Organic mulch
Fabric mulch
Rock mulch
IPM for Weeds
Organic mulches
Before applying
mulch, make sure the
soil is weed-free
• Apply to adequate
depth and keep away
from base of trees
and shrubs
• Break down and need
to be replenished
• More effective if
applied over fabric
Large or medium-sized
mulches:
apply 3 to 4 inches
deep
Fine mulches:
apply 2 inches
deep
IPM for Weeds
Rock mulches
Advantages
• More permanent than
organic mulches
• Do not need to be
replenished much
Disadvantages
• Difficult to keep clean
• Don’t add anything to
improve soil
• Make it hard to
remove weeds
Rock is most
effective if placed
over synthetic mulch
or fabric barrier
IPM for Weeds
Synthetic mulches
• Used under organic
or rock mulches
• Use landscape
fabric; avoid plastic
mulches
• Landscape fabrics
allow water and air to
pass through and
last a long time
• Avoid sun exposure
IPM for Weeds
Synthetic mulches
Put fabric down
with U-shaped
Cut X in fabric
nails and overlap
edges
Dig
planting
hole
Cover with
Place plant in hole mulch
IPM for Weeds
Maintaining mulch
• Replenish mulch as
needed
• Keep mulch at the
proper depth
• Remove weeds
by hand
• Avoid disrupting
the mulch
Some weeds may grow
on top of mulches
IPM for Weeds
Pull them out
• Remove weeds as
you see them
• Remove weeds
before they set
seed
• Remove entire
plant
• Irrigate before
hand-weeding
• Grasp the weed by
its base and roll it
back and forth to
loosen its roots
IPM for Weeds
Tools make weeding easier
Perennial weeds
Dig up and destroy roots,
stems, tubers
Dandelion
knife
Annual weeds
Control with various hoes
Hula hoe
Hand tine
Garden hoe
IPM for Weeds
Tools make weeding easier
Adaptive gardening tool
IPM for Weeds
Control with hot water
and flaming
Hot water
• Effective against
annuals or young
perennials
• Treat foliage and
stems
Flaming
• Effective against
young annual weeds
• Pass the flame over
the leaves
IPM for Weeds
Weed-eating animals
• Be careful not to use
them around desirable
plants
• Protect them from dogs
or other predators
• Provide other food
sources and water
• Remove from areas
where pesticides are
applied
• Dispose of animal waste
Weed-eating geese
IPM for Weeds
Do you need herbicides?
Herbicides are pesticides that control weeds
• Hand-weeding and
mulching usually provide
adequate control
• Use for special situations
• Figure out the underlying
cause
• Use preventive methods
• Choose one labeled for
the weed and safe around
desirable plants
IPM for Weeds
Herbicides can injure
garden plants
Preemergent
• Before seedlings
emerge
Postemergent
• After weeds
emerge
Selective
• Kills specific types of weeds
Nonselective
• Kills most vegetation
IPM for Weeds
Herbicides can injure
garden plants
• When labels
are not
followed
• When drift
occurs
• When roots
are buried
beneath
treated areas
Glyphosate
injury
Dicamba
injury
Special problem herbicides
Glyphosate
Dicamba
2,4-D
2,4-D
injury
IPM for Weeds
Follow the label
• Follow all directions
• Use only the amount needed
• Don’t overirrigate
Wear proper
clothing
Make sure the product is
labeled for your weed
and is registered for the
area where it will be used
IPM for Weeds
Applying glyphosate
• Most common herbicide
• Kills most weeds, but can
damage desirable plants
• Pre-mixed solutions may
be too weak to control
Place a funnel over
perennials
the spray nozzle to
avoid drift
Mix up your own solution
• Use hand-held applicator or • Treat when weeds are
actively growing
low-pressure pump sprayer
• Measure product and water • Small areas: dig up
• Rinse the measuring
propagules, irrigate, treat
container
• Large areas: treat,
• If necessary, add surfactant
irrigate, treat again
IPM for Weeds
Is your approach working?
Weeds will decrease
• Manage the area
properly
 Competitive
plantings
 Barriers
 Well-maintained
mulches
 Drip irrigation or
other low-output
irrigation system
• Remove weeds regularly
 As you see them
 Before they set seed
IPM for Weeds
Where can you get more
information?
www.ipm.ucdavis.edu
County UC
Cooperative
Extension
Offices
www.ucanr.org
IPM for Weeds
Managing weeds in lawns
New lawns
• Prepare planting site properly
• Select an adaptable grass plant
www.ipm.ucdavis.edu
Established lawns
• Water, fertilize, and
mow properly
• Monitor and remove
weeds by hand
• Use herbicides as a
last resort
IPM for Weeds
Managing weeds
in annual beds
Before planting
• Cultivate, irrigate,
cultivate
• Solarize the soil
Maintenance
• Hand-weed
• Mulch around plants
• Plant cover crops on
empty beds
IPM for Weeds
Managing weeds in
landscape beds
• Remove all weeds
before planting
• Plant competitive
plants, eliminate
bare ground
• Put down a fabric
barrier with mulch
• Remove weeds by
hand
• Provide proper water
• Use physical barriers
Ground
covers
Fabric
barrier with
rock mulch
Mowing
strip
IPM for Weeds
Managing weeds around trees
• Keep weeds and
other plants away
from the base of
trees
• Consider mulches
Newspaper mulch
1. Wet newspaper and
layer around tree
2. Place compost on top
Remove weeds
before mulching
Use organic mulch
with or without fabric
barriers
IPM for Weeds
Managing weeds
in hardscapes
Sidewalk or driveway cracks
• Use screwdriver or weed knife
Weed knife
• Apply less-toxic materials
• Seal with crack filler or foam
• Flame or treat with hot water Fence lines
• Fences supported
by concrete are
best
• In landscaped
areas, mulch
along fence lines
IPM for Weeds
IPM for Weeds
Cheryl A. Reynolds, Mary Louise Flint, and Joyce F. Strand
University of California Statewide IPM Program
Funding of this project was provided by the Elvenia J. Slosson Endowment Fund
and Cooperative State Research, Education, and Extension Service, USDA
Advisory Committee:
Bethallyn Black – UC Cooperative Extension Contra Costa County
Pamela Geisel – UC Statewide Master Gardener Academic Coordinator
Judy McClure – UC Cooperative Extension Sacramento County
Cheryl Wilen - UC Cooperative Extension UC Statewide IPM Program
Photography: Jack Kelly Clark, Cheryl Reynolds, Statewide IPM Collection
Illustrations: Chris O’Connor
Special thanks: Anita Clevenger, Susan Poirier, Bill Pierce, Ruth Ann Weber